1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Infrastructure for profiling code inserted by 'gcc -pg'.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally ported from the -rt patch by:
9 * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code in the latency_tracer, that is:
12 *
13 * Copyright (C) 2004-2006 Ingo Molnar
14 * Copyright (C) 2004 Nadia Yvette Chambers
15 */
16
17 #include <linux/stop_machine.h>
18 #include <linux/clocksource.h>
19 #include <linux/sched/task.h>
20 #include <linux/kallsyms.h>
21 #include <linux/security.h>
22 #include <linux/seq_file.h>
23 #include <linux/tracefs.h>
24 #include <linux/hardirq.h>
25 #include <linux/kthread.h>
26 #include <linux/uaccess.h>
27 #include <linux/bsearch.h>
28 #include <linux/module.h>
29 #include <linux/ftrace.h>
30 #include <linux/sysctl.h>
31 #include <linux/slab.h>
32 #include <linux/ctype.h>
33 #include <linux/sort.h>
34 #include <linux/list.h>
35 #include <linux/hash.h>
36 #include <linux/rcupdate.h>
37 #include <linux/kprobes.h>
38
39 #include <trace/events/sched.h>
40
41 #include <asm/sections.h>
42 #include <asm/setup.h>
43
44 #include "ftrace_internal.h"
45 #include "trace_output.h"
46 #include "trace_stat.h"
47
48 #define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
49
50 #define FTRACE_WARN_ON(cond) \
51 ({ \
52 int ___r = cond; \
53 if (WARN_ON(___r)) \
54 ftrace_kill(); \
55 ___r; \
56 })
57
58 #define FTRACE_WARN_ON_ONCE(cond) \
59 ({ \
60 int ___r = cond; \
61 if (WARN_ON_ONCE(___r)) \
62 ftrace_kill(); \
63 ___r; \
64 })
65
66 /* hash bits for specific function selection */
67 #define FTRACE_HASH_DEFAULT_BITS 10
68 #define FTRACE_HASH_MAX_BITS 12
69
70 #ifdef CONFIG_DYNAMIC_FTRACE
71 #define INIT_OPS_HASH(opsname) \
72 .func_hash = &opsname.local_hash, \
73 .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
74 #else
75 #define INIT_OPS_HASH(opsname)
76 #endif
77
78 enum {
79 FTRACE_MODIFY_ENABLE_FL = (1 << 0),
80 FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
81 };
82
83 struct ftrace_ops ftrace_list_end __read_mostly = {
84 .func = ftrace_stub,
85 .flags = FTRACE_OPS_FL_STUB,
86 INIT_OPS_HASH(ftrace_list_end)
87 };
88
89 /* ftrace_enabled is a method to turn ftrace on or off */
90 int ftrace_enabled __read_mostly;
91 static int __maybe_unused last_ftrace_enabled;
92
93 /* Current function tracing op */
94 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
95 /* What to set function_trace_op to */
96 static struct ftrace_ops *set_function_trace_op;
97
ftrace_pids_enabled(struct ftrace_ops * ops)98 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
99 {
100 struct trace_array *tr;
101
102 if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
103 return false;
104
105 tr = ops->private;
106
107 return tr->function_pids != NULL || tr->function_no_pids != NULL;
108 }
109
110 static void ftrace_update_trampoline(struct ftrace_ops *ops);
111
112 /*
113 * ftrace_disabled is set when an anomaly is discovered.
114 * ftrace_disabled is much stronger than ftrace_enabled.
115 */
116 static int ftrace_disabled __read_mostly;
117
118 DEFINE_MUTEX(ftrace_lock);
119
120 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
121 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
122 struct ftrace_ops global_ops;
123
124 /* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
125 void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
126 struct ftrace_ops *op, struct ftrace_regs *fregs);
127
ftrace_ops_init(struct ftrace_ops * ops)128 static inline void ftrace_ops_init(struct ftrace_ops *ops)
129 {
130 #ifdef CONFIG_DYNAMIC_FTRACE
131 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
132 mutex_init(&ops->local_hash.regex_lock);
133 ops->func_hash = &ops->local_hash;
134 ops->flags |= FTRACE_OPS_FL_INITIALIZED;
135 }
136 #endif
137 }
138
ftrace_pid_func(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)139 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
140 struct ftrace_ops *op, struct ftrace_regs *fregs)
141 {
142 struct trace_array *tr = op->private;
143 int pid;
144
145 if (tr) {
146 pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
147 if (pid == FTRACE_PID_IGNORE)
148 return;
149 if (pid != FTRACE_PID_TRACE &&
150 pid != current->pid)
151 return;
152 }
153
154 op->saved_func(ip, parent_ip, op, fregs);
155 }
156
ftrace_sync_ipi(void * data)157 static void ftrace_sync_ipi(void *data)
158 {
159 /* Probably not needed, but do it anyway */
160 smp_rmb();
161 }
162
ftrace_ops_get_list_func(struct ftrace_ops * ops)163 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
164 {
165 /*
166 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
167 * then it needs to call the list anyway.
168 */
169 if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
170 FTRACE_FORCE_LIST_FUNC)
171 return ftrace_ops_list_func;
172
173 return ftrace_ops_get_func(ops);
174 }
175
update_ftrace_function(void)176 static void update_ftrace_function(void)
177 {
178 ftrace_func_t func;
179
180 /*
181 * Prepare the ftrace_ops that the arch callback will use.
182 * If there's only one ftrace_ops registered, the ftrace_ops_list
183 * will point to the ops we want.
184 */
185 set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
186 lockdep_is_held(&ftrace_lock));
187
188 /* If there's no ftrace_ops registered, just call the stub function */
189 if (set_function_trace_op == &ftrace_list_end) {
190 func = ftrace_stub;
191
192 /*
193 * If we are at the end of the list and this ops is
194 * recursion safe and not dynamic and the arch supports passing ops,
195 * then have the mcount trampoline call the function directly.
196 */
197 } else if (rcu_dereference_protected(ftrace_ops_list->next,
198 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
199 func = ftrace_ops_get_list_func(ftrace_ops_list);
200
201 } else {
202 /* Just use the default ftrace_ops */
203 set_function_trace_op = &ftrace_list_end;
204 func = ftrace_ops_list_func;
205 }
206
207 update_function_graph_func();
208
209 /* If there's no change, then do nothing more here */
210 if (ftrace_trace_function == func)
211 return;
212
213 /*
214 * If we are using the list function, it doesn't care
215 * about the function_trace_ops.
216 */
217 if (func == ftrace_ops_list_func) {
218 ftrace_trace_function = func;
219 /*
220 * Don't even bother setting function_trace_ops,
221 * it would be racy to do so anyway.
222 */
223 return;
224 }
225
226 #ifndef CONFIG_DYNAMIC_FTRACE
227 /*
228 * For static tracing, we need to be a bit more careful.
229 * The function change takes affect immediately. Thus,
230 * we need to coordinate the setting of the function_trace_ops
231 * with the setting of the ftrace_trace_function.
232 *
233 * Set the function to the list ops, which will call the
234 * function we want, albeit indirectly, but it handles the
235 * ftrace_ops and doesn't depend on function_trace_op.
236 */
237 ftrace_trace_function = ftrace_ops_list_func;
238 /*
239 * Make sure all CPUs see this. Yes this is slow, but static
240 * tracing is slow and nasty to have enabled.
241 */
242 synchronize_rcu_tasks_rude();
243 /* Now all cpus are using the list ops. */
244 function_trace_op = set_function_trace_op;
245 /* Make sure the function_trace_op is visible on all CPUs */
246 smp_wmb();
247 /* Nasty way to force a rmb on all cpus */
248 smp_call_function(ftrace_sync_ipi, NULL, 1);
249 /* OK, we are all set to update the ftrace_trace_function now! */
250 #endif /* !CONFIG_DYNAMIC_FTRACE */
251
252 ftrace_trace_function = func;
253 }
254
add_ftrace_ops(struct ftrace_ops __rcu ** list,struct ftrace_ops * ops)255 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
256 struct ftrace_ops *ops)
257 {
258 rcu_assign_pointer(ops->next, *list);
259
260 /*
261 * We are entering ops into the list but another
262 * CPU might be walking that list. We need to make sure
263 * the ops->next pointer is valid before another CPU sees
264 * the ops pointer included into the list.
265 */
266 rcu_assign_pointer(*list, ops);
267 }
268
remove_ftrace_ops(struct ftrace_ops __rcu ** list,struct ftrace_ops * ops)269 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
270 struct ftrace_ops *ops)
271 {
272 struct ftrace_ops **p;
273
274 /*
275 * If we are removing the last function, then simply point
276 * to the ftrace_stub.
277 */
278 if (rcu_dereference_protected(*list,
279 lockdep_is_held(&ftrace_lock)) == ops &&
280 rcu_dereference_protected(ops->next,
281 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
282 *list = &ftrace_list_end;
283 return 0;
284 }
285
286 for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
287 if (*p == ops)
288 break;
289
290 if (*p != ops)
291 return -1;
292
293 *p = (*p)->next;
294 return 0;
295 }
296
297 static void ftrace_update_trampoline(struct ftrace_ops *ops);
298
__register_ftrace_function(struct ftrace_ops * ops)299 int __register_ftrace_function(struct ftrace_ops *ops)
300 {
301 if (ops->flags & FTRACE_OPS_FL_DELETED)
302 return -EINVAL;
303
304 if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
305 return -EBUSY;
306
307 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
308 /*
309 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
310 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
311 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
312 */
313 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
314 !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
315 return -EINVAL;
316
317 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
318 ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
319 #endif
320 if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
321 return -EBUSY;
322
323 if (!is_kernel_core_data((unsigned long)ops))
324 ops->flags |= FTRACE_OPS_FL_DYNAMIC;
325
326 add_ftrace_ops(&ftrace_ops_list, ops);
327
328 /* Always save the function, and reset at unregistering */
329 ops->saved_func = ops->func;
330
331 if (ftrace_pids_enabled(ops))
332 ops->func = ftrace_pid_func;
333
334 ftrace_update_trampoline(ops);
335
336 if (ftrace_enabled)
337 update_ftrace_function();
338
339 return 0;
340 }
341
__unregister_ftrace_function(struct ftrace_ops * ops)342 int __unregister_ftrace_function(struct ftrace_ops *ops)
343 {
344 int ret;
345
346 if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
347 return -EBUSY;
348
349 ret = remove_ftrace_ops(&ftrace_ops_list, ops);
350
351 if (ret < 0)
352 return ret;
353
354 if (ftrace_enabled)
355 update_ftrace_function();
356
357 ops->func = ops->saved_func;
358
359 return 0;
360 }
361
ftrace_update_pid_func(void)362 static void ftrace_update_pid_func(void)
363 {
364 struct ftrace_ops *op;
365
366 /* Only do something if we are tracing something */
367 if (ftrace_trace_function == ftrace_stub)
368 return;
369
370 do_for_each_ftrace_op(op, ftrace_ops_list) {
371 if (op->flags & FTRACE_OPS_FL_PID) {
372 op->func = ftrace_pids_enabled(op) ?
373 ftrace_pid_func : op->saved_func;
374 ftrace_update_trampoline(op);
375 }
376 } while_for_each_ftrace_op(op);
377
378 update_ftrace_function();
379 }
380
381 #ifdef CONFIG_FUNCTION_PROFILER
382 struct ftrace_profile {
383 struct hlist_node node;
384 unsigned long ip;
385 unsigned long counter;
386 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
387 unsigned long long time;
388 unsigned long long time_squared;
389 #endif
390 };
391
392 struct ftrace_profile_page {
393 struct ftrace_profile_page *next;
394 unsigned long index;
395 struct ftrace_profile records[];
396 };
397
398 struct ftrace_profile_stat {
399 atomic_t disabled;
400 struct hlist_head *hash;
401 struct ftrace_profile_page *pages;
402 struct ftrace_profile_page *start;
403 struct tracer_stat stat;
404 };
405
406 #define PROFILE_RECORDS_SIZE \
407 (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
408
409 #define PROFILES_PER_PAGE \
410 (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
411
412 static int ftrace_profile_enabled __read_mostly;
413
414 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
415 static DEFINE_MUTEX(ftrace_profile_lock);
416
417 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
418
419 #define FTRACE_PROFILE_HASH_BITS 10
420 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
421
422 static void *
function_stat_next(void * v,int idx)423 function_stat_next(void *v, int idx)
424 {
425 struct ftrace_profile *rec = v;
426 struct ftrace_profile_page *pg;
427
428 pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
429
430 again:
431 if (idx != 0)
432 rec++;
433
434 if ((void *)rec >= (void *)&pg->records[pg->index]) {
435 pg = pg->next;
436 if (!pg)
437 return NULL;
438 rec = &pg->records[0];
439 if (!rec->counter)
440 goto again;
441 }
442
443 return rec;
444 }
445
function_stat_start(struct tracer_stat * trace)446 static void *function_stat_start(struct tracer_stat *trace)
447 {
448 struct ftrace_profile_stat *stat =
449 container_of(trace, struct ftrace_profile_stat, stat);
450
451 if (!stat || !stat->start)
452 return NULL;
453
454 return function_stat_next(&stat->start->records[0], 0);
455 }
456
457 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
458 /* function graph compares on total time */
function_stat_cmp(const void * p1,const void * p2)459 static int function_stat_cmp(const void *p1, const void *p2)
460 {
461 const struct ftrace_profile *a = p1;
462 const struct ftrace_profile *b = p2;
463
464 if (a->time < b->time)
465 return -1;
466 if (a->time > b->time)
467 return 1;
468 else
469 return 0;
470 }
471 #else
472 /* not function graph compares against hits */
function_stat_cmp(const void * p1,const void * p2)473 static int function_stat_cmp(const void *p1, const void *p2)
474 {
475 const struct ftrace_profile *a = p1;
476 const struct ftrace_profile *b = p2;
477
478 if (a->counter < b->counter)
479 return -1;
480 if (a->counter > b->counter)
481 return 1;
482 else
483 return 0;
484 }
485 #endif
486
function_stat_headers(struct seq_file * m)487 static int function_stat_headers(struct seq_file *m)
488 {
489 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
490 seq_puts(m, " Function "
491 "Hit Time Avg s^2\n"
492 " -------- "
493 "--- ---- --- ---\n");
494 #else
495 seq_puts(m, " Function Hit\n"
496 " -------- ---\n");
497 #endif
498 return 0;
499 }
500
function_stat_show(struct seq_file * m,void * v)501 static int function_stat_show(struct seq_file *m, void *v)
502 {
503 struct ftrace_profile *rec = v;
504 char str[KSYM_SYMBOL_LEN];
505 int ret = 0;
506 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
507 static struct trace_seq s;
508 unsigned long long avg;
509 unsigned long long stddev;
510 #endif
511 mutex_lock(&ftrace_profile_lock);
512
513 /* we raced with function_profile_reset() */
514 if (unlikely(rec->counter == 0)) {
515 ret = -EBUSY;
516 goto out;
517 }
518
519 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
520 avg = div64_ul(rec->time, rec->counter);
521 if (tracing_thresh && (avg < tracing_thresh))
522 goto out;
523 #endif
524
525 kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
526 seq_printf(m, " %-30.30s %10lu", str, rec->counter);
527
528 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
529 seq_puts(m, " ");
530
531 /* Sample standard deviation (s^2) */
532 if (rec->counter <= 1)
533 stddev = 0;
534 else {
535 /*
536 * Apply Welford's method:
537 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
538 */
539 stddev = rec->counter * rec->time_squared -
540 rec->time * rec->time;
541
542 /*
543 * Divide only 1000 for ns^2 -> us^2 conversion.
544 * trace_print_graph_duration will divide 1000 again.
545 */
546 stddev = div64_ul(stddev,
547 rec->counter * (rec->counter - 1) * 1000);
548 }
549
550 trace_seq_init(&s);
551 trace_print_graph_duration(rec->time, &s);
552 trace_seq_puts(&s, " ");
553 trace_print_graph_duration(avg, &s);
554 trace_seq_puts(&s, " ");
555 trace_print_graph_duration(stddev, &s);
556 trace_print_seq(m, &s);
557 #endif
558 seq_putc(m, '\n');
559 out:
560 mutex_unlock(&ftrace_profile_lock);
561
562 return ret;
563 }
564
ftrace_profile_reset(struct ftrace_profile_stat * stat)565 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
566 {
567 struct ftrace_profile_page *pg;
568
569 pg = stat->pages = stat->start;
570
571 while (pg) {
572 memset(pg->records, 0, PROFILE_RECORDS_SIZE);
573 pg->index = 0;
574 pg = pg->next;
575 }
576
577 memset(stat->hash, 0,
578 FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
579 }
580
ftrace_profile_pages_init(struct ftrace_profile_stat * stat)581 static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
582 {
583 struct ftrace_profile_page *pg;
584 int functions;
585 int pages;
586 int i;
587
588 /* If we already allocated, do nothing */
589 if (stat->pages)
590 return 0;
591
592 stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
593 if (!stat->pages)
594 return -ENOMEM;
595
596 #ifdef CONFIG_DYNAMIC_FTRACE
597 functions = ftrace_update_tot_cnt;
598 #else
599 /*
600 * We do not know the number of functions that exist because
601 * dynamic tracing is what counts them. With past experience
602 * we have around 20K functions. That should be more than enough.
603 * It is highly unlikely we will execute every function in
604 * the kernel.
605 */
606 functions = 20000;
607 #endif
608
609 pg = stat->start = stat->pages;
610
611 pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
612
613 for (i = 1; i < pages; i++) {
614 pg->next = (void *)get_zeroed_page(GFP_KERNEL);
615 if (!pg->next)
616 goto out_free;
617 pg = pg->next;
618 }
619
620 return 0;
621
622 out_free:
623 pg = stat->start;
624 while (pg) {
625 unsigned long tmp = (unsigned long)pg;
626
627 pg = pg->next;
628 free_page(tmp);
629 }
630
631 stat->pages = NULL;
632 stat->start = NULL;
633
634 return -ENOMEM;
635 }
636
ftrace_profile_init_cpu(int cpu)637 static int ftrace_profile_init_cpu(int cpu)
638 {
639 struct ftrace_profile_stat *stat;
640 int size;
641
642 stat = &per_cpu(ftrace_profile_stats, cpu);
643
644 if (stat->hash) {
645 /* If the profile is already created, simply reset it */
646 ftrace_profile_reset(stat);
647 return 0;
648 }
649
650 /*
651 * We are profiling all functions, but usually only a few thousand
652 * functions are hit. We'll make a hash of 1024 items.
653 */
654 size = FTRACE_PROFILE_HASH_SIZE;
655
656 stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
657
658 if (!stat->hash)
659 return -ENOMEM;
660
661 /* Preallocate the function profiling pages */
662 if (ftrace_profile_pages_init(stat) < 0) {
663 kfree(stat->hash);
664 stat->hash = NULL;
665 return -ENOMEM;
666 }
667
668 return 0;
669 }
670
ftrace_profile_init(void)671 static int ftrace_profile_init(void)
672 {
673 int cpu;
674 int ret = 0;
675
676 for_each_possible_cpu(cpu) {
677 ret = ftrace_profile_init_cpu(cpu);
678 if (ret)
679 break;
680 }
681
682 return ret;
683 }
684
685 /* interrupts must be disabled */
686 static struct ftrace_profile *
ftrace_find_profiled_func(struct ftrace_profile_stat * stat,unsigned long ip)687 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
688 {
689 struct ftrace_profile *rec;
690 struct hlist_head *hhd;
691 unsigned long key;
692
693 key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
694 hhd = &stat->hash[key];
695
696 if (hlist_empty(hhd))
697 return NULL;
698
699 hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
700 if (rec->ip == ip)
701 return rec;
702 }
703
704 return NULL;
705 }
706
ftrace_add_profile(struct ftrace_profile_stat * stat,struct ftrace_profile * rec)707 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
708 struct ftrace_profile *rec)
709 {
710 unsigned long key;
711
712 key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
713 hlist_add_head_rcu(&rec->node, &stat->hash[key]);
714 }
715
716 /*
717 * The memory is already allocated, this simply finds a new record to use.
718 */
719 static struct ftrace_profile *
ftrace_profile_alloc(struct ftrace_profile_stat * stat,unsigned long ip)720 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
721 {
722 struct ftrace_profile *rec = NULL;
723
724 /* prevent recursion (from NMIs) */
725 if (atomic_inc_return(&stat->disabled) != 1)
726 goto out;
727
728 /*
729 * Try to find the function again since an NMI
730 * could have added it
731 */
732 rec = ftrace_find_profiled_func(stat, ip);
733 if (rec)
734 goto out;
735
736 if (stat->pages->index == PROFILES_PER_PAGE) {
737 if (!stat->pages->next)
738 goto out;
739 stat->pages = stat->pages->next;
740 }
741
742 rec = &stat->pages->records[stat->pages->index++];
743 rec->ip = ip;
744 ftrace_add_profile(stat, rec);
745
746 out:
747 atomic_dec(&stat->disabled);
748
749 return rec;
750 }
751
752 static void
function_profile_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * ops,struct ftrace_regs * fregs)753 function_profile_call(unsigned long ip, unsigned long parent_ip,
754 struct ftrace_ops *ops, struct ftrace_regs *fregs)
755 {
756 struct ftrace_profile_stat *stat;
757 struct ftrace_profile *rec;
758 unsigned long flags;
759
760 if (!ftrace_profile_enabled)
761 return;
762
763 local_irq_save(flags);
764
765 stat = this_cpu_ptr(&ftrace_profile_stats);
766 if (!stat->hash || !ftrace_profile_enabled)
767 goto out;
768
769 rec = ftrace_find_profiled_func(stat, ip);
770 if (!rec) {
771 rec = ftrace_profile_alloc(stat, ip);
772 if (!rec)
773 goto out;
774 }
775
776 rec->counter++;
777 out:
778 local_irq_restore(flags);
779 }
780
781 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
782 static bool fgraph_graph_time = true;
783
ftrace_graph_graph_time_control(bool enable)784 void ftrace_graph_graph_time_control(bool enable)
785 {
786 fgraph_graph_time = enable;
787 }
788
profile_graph_entry(struct ftrace_graph_ent * trace)789 static int profile_graph_entry(struct ftrace_graph_ent *trace)
790 {
791 struct ftrace_ret_stack *ret_stack;
792
793 function_profile_call(trace->func, 0, NULL, NULL);
794
795 /* If function graph is shutting down, ret_stack can be NULL */
796 if (!current->ret_stack)
797 return 0;
798
799 ret_stack = ftrace_graph_get_ret_stack(current, 0);
800 if (ret_stack)
801 ret_stack->subtime = 0;
802
803 return 1;
804 }
805
profile_graph_return(struct ftrace_graph_ret * trace)806 static void profile_graph_return(struct ftrace_graph_ret *trace)
807 {
808 struct ftrace_ret_stack *ret_stack;
809 struct ftrace_profile_stat *stat;
810 unsigned long long calltime;
811 struct ftrace_profile *rec;
812 unsigned long flags;
813
814 local_irq_save(flags);
815 stat = this_cpu_ptr(&ftrace_profile_stats);
816 if (!stat->hash || !ftrace_profile_enabled)
817 goto out;
818
819 /* If the calltime was zero'd ignore it */
820 if (!trace->calltime)
821 goto out;
822
823 calltime = trace->rettime - trace->calltime;
824
825 if (!fgraph_graph_time) {
826
827 /* Append this call time to the parent time to subtract */
828 ret_stack = ftrace_graph_get_ret_stack(current, 1);
829 if (ret_stack)
830 ret_stack->subtime += calltime;
831
832 ret_stack = ftrace_graph_get_ret_stack(current, 0);
833 if (ret_stack && ret_stack->subtime < calltime)
834 calltime -= ret_stack->subtime;
835 else
836 calltime = 0;
837 }
838
839 rec = ftrace_find_profiled_func(stat, trace->func);
840 if (rec) {
841 rec->time += calltime;
842 rec->time_squared += calltime * calltime;
843 }
844
845 out:
846 local_irq_restore(flags);
847 }
848
849 static struct fgraph_ops fprofiler_ops = {
850 .entryfunc = &profile_graph_entry,
851 .retfunc = &profile_graph_return,
852 };
853
register_ftrace_profiler(void)854 static int register_ftrace_profiler(void)
855 {
856 return register_ftrace_graph(&fprofiler_ops);
857 }
858
unregister_ftrace_profiler(void)859 static void unregister_ftrace_profiler(void)
860 {
861 unregister_ftrace_graph(&fprofiler_ops);
862 }
863 #else
864 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
865 .func = function_profile_call,
866 .flags = FTRACE_OPS_FL_INITIALIZED,
867 INIT_OPS_HASH(ftrace_profile_ops)
868 };
869
register_ftrace_profiler(void)870 static int register_ftrace_profiler(void)
871 {
872 return register_ftrace_function(&ftrace_profile_ops);
873 }
874
unregister_ftrace_profiler(void)875 static void unregister_ftrace_profiler(void)
876 {
877 unregister_ftrace_function(&ftrace_profile_ops);
878 }
879 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
880
881 static ssize_t
ftrace_profile_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)882 ftrace_profile_write(struct file *filp, const char __user *ubuf,
883 size_t cnt, loff_t *ppos)
884 {
885 unsigned long val;
886 int ret;
887
888 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
889 if (ret)
890 return ret;
891
892 val = !!val;
893
894 mutex_lock(&ftrace_profile_lock);
895 if (ftrace_profile_enabled ^ val) {
896 if (val) {
897 ret = ftrace_profile_init();
898 if (ret < 0) {
899 cnt = ret;
900 goto out;
901 }
902
903 ret = register_ftrace_profiler();
904 if (ret < 0) {
905 cnt = ret;
906 goto out;
907 }
908 ftrace_profile_enabled = 1;
909 } else {
910 ftrace_profile_enabled = 0;
911 /*
912 * unregister_ftrace_profiler calls stop_machine
913 * so this acts like an synchronize_rcu.
914 */
915 unregister_ftrace_profiler();
916 }
917 }
918 out:
919 mutex_unlock(&ftrace_profile_lock);
920
921 *ppos += cnt;
922
923 return cnt;
924 }
925
926 static ssize_t
ftrace_profile_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)927 ftrace_profile_read(struct file *filp, char __user *ubuf,
928 size_t cnt, loff_t *ppos)
929 {
930 char buf[64]; /* big enough to hold a number */
931 int r;
932
933 r = sprintf(buf, "%u\n", ftrace_profile_enabled);
934 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
935 }
936
937 static const struct file_operations ftrace_profile_fops = {
938 .open = tracing_open_generic,
939 .read = ftrace_profile_read,
940 .write = ftrace_profile_write,
941 .llseek = default_llseek,
942 };
943
944 /* used to initialize the real stat files */
945 static struct tracer_stat function_stats __initdata = {
946 .name = "functions",
947 .stat_start = function_stat_start,
948 .stat_next = function_stat_next,
949 .stat_cmp = function_stat_cmp,
950 .stat_headers = function_stat_headers,
951 .stat_show = function_stat_show
952 };
953
ftrace_profile_tracefs(struct dentry * d_tracer)954 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
955 {
956 struct ftrace_profile_stat *stat;
957 char *name;
958 int ret;
959 int cpu;
960
961 for_each_possible_cpu(cpu) {
962 stat = &per_cpu(ftrace_profile_stats, cpu);
963
964 name = kasprintf(GFP_KERNEL, "function%d", cpu);
965 if (!name) {
966 /*
967 * The files created are permanent, if something happens
968 * we still do not free memory.
969 */
970 WARN(1,
971 "Could not allocate stat file for cpu %d\n",
972 cpu);
973 return;
974 }
975 stat->stat = function_stats;
976 stat->stat.name = name;
977 ret = register_stat_tracer(&stat->stat);
978 if (ret) {
979 WARN(1,
980 "Could not register function stat for cpu %d\n",
981 cpu);
982 kfree(name);
983 return;
984 }
985 }
986
987 trace_create_file("function_profile_enabled",
988 TRACE_MODE_WRITE, d_tracer, NULL,
989 &ftrace_profile_fops);
990 }
991
992 #else /* CONFIG_FUNCTION_PROFILER */
ftrace_profile_tracefs(struct dentry * d_tracer)993 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
994 {
995 }
996 #endif /* CONFIG_FUNCTION_PROFILER */
997
998 #ifdef CONFIG_DYNAMIC_FTRACE
999
1000 static struct ftrace_ops *removed_ops;
1001
1002 /*
1003 * Set when doing a global update, like enabling all recs or disabling them.
1004 * It is not set when just updating a single ftrace_ops.
1005 */
1006 static bool update_all_ops;
1007
1008 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
1009 # error Dynamic ftrace depends on MCOUNT_RECORD
1010 #endif
1011
1012 struct ftrace_func_probe {
1013 struct ftrace_probe_ops *probe_ops;
1014 struct ftrace_ops ops;
1015 struct trace_array *tr;
1016 struct list_head list;
1017 void *data;
1018 int ref;
1019 };
1020
1021 /*
1022 * We make these constant because no one should touch them,
1023 * but they are used as the default "empty hash", to avoid allocating
1024 * it all the time. These are in a read only section such that if
1025 * anyone does try to modify it, it will cause an exception.
1026 */
1027 static const struct hlist_head empty_buckets[1];
1028 static const struct ftrace_hash empty_hash = {
1029 .buckets = (struct hlist_head *)empty_buckets,
1030 };
1031 #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
1032
1033 struct ftrace_ops global_ops = {
1034 .func = ftrace_stub,
1035 .local_hash.notrace_hash = EMPTY_HASH,
1036 .local_hash.filter_hash = EMPTY_HASH,
1037 INIT_OPS_HASH(global_ops)
1038 .flags = FTRACE_OPS_FL_INITIALIZED |
1039 FTRACE_OPS_FL_PID,
1040 };
1041
1042 /*
1043 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1044 */
ftrace_ops_trampoline(unsigned long addr)1045 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1046 {
1047 struct ftrace_ops *op = NULL;
1048
1049 /*
1050 * Some of the ops may be dynamically allocated,
1051 * they are freed after a synchronize_rcu().
1052 */
1053 preempt_disable_notrace();
1054
1055 do_for_each_ftrace_op(op, ftrace_ops_list) {
1056 /*
1057 * This is to check for dynamically allocated trampolines.
1058 * Trampolines that are in kernel text will have
1059 * core_kernel_text() return true.
1060 */
1061 if (op->trampoline && op->trampoline_size)
1062 if (addr >= op->trampoline &&
1063 addr < op->trampoline + op->trampoline_size) {
1064 preempt_enable_notrace();
1065 return op;
1066 }
1067 } while_for_each_ftrace_op(op);
1068 preempt_enable_notrace();
1069
1070 return NULL;
1071 }
1072
1073 /*
1074 * This is used by __kernel_text_address() to return true if the
1075 * address is on a dynamically allocated trampoline that would
1076 * not return true for either core_kernel_text() or
1077 * is_module_text_address().
1078 */
is_ftrace_trampoline(unsigned long addr)1079 bool is_ftrace_trampoline(unsigned long addr)
1080 {
1081 return ftrace_ops_trampoline(addr) != NULL;
1082 }
1083
1084 struct ftrace_page {
1085 struct ftrace_page *next;
1086 struct dyn_ftrace *records;
1087 int index;
1088 int order;
1089 };
1090
1091 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
1092 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1093
1094 static struct ftrace_page *ftrace_pages_start;
1095 static struct ftrace_page *ftrace_pages;
1096
1097 static __always_inline unsigned long
ftrace_hash_key(struct ftrace_hash * hash,unsigned long ip)1098 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1099 {
1100 if (hash->size_bits > 0)
1101 return hash_long(ip, hash->size_bits);
1102
1103 return 0;
1104 }
1105
1106 /* Only use this function if ftrace_hash_empty() has already been tested */
1107 static __always_inline struct ftrace_func_entry *
__ftrace_lookup_ip(struct ftrace_hash * hash,unsigned long ip)1108 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1109 {
1110 unsigned long key;
1111 struct ftrace_func_entry *entry;
1112 struct hlist_head *hhd;
1113
1114 key = ftrace_hash_key(hash, ip);
1115 hhd = &hash->buckets[key];
1116
1117 hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1118 if (entry->ip == ip)
1119 return entry;
1120 }
1121 return NULL;
1122 }
1123
1124 /**
1125 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1126 * @hash: The hash to look at
1127 * @ip: The instruction pointer to test
1128 *
1129 * Search a given @hash to see if a given instruction pointer (@ip)
1130 * exists in it.
1131 *
1132 * Returns the entry that holds the @ip if found. NULL otherwise.
1133 */
1134 struct ftrace_func_entry *
ftrace_lookup_ip(struct ftrace_hash * hash,unsigned long ip)1135 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1136 {
1137 if (ftrace_hash_empty(hash))
1138 return NULL;
1139
1140 return __ftrace_lookup_ip(hash, ip);
1141 }
1142
__add_hash_entry(struct ftrace_hash * hash,struct ftrace_func_entry * entry)1143 static void __add_hash_entry(struct ftrace_hash *hash,
1144 struct ftrace_func_entry *entry)
1145 {
1146 struct hlist_head *hhd;
1147 unsigned long key;
1148
1149 key = ftrace_hash_key(hash, entry->ip);
1150 hhd = &hash->buckets[key];
1151 hlist_add_head(&entry->hlist, hhd);
1152 hash->count++;
1153 }
1154
add_hash_entry(struct ftrace_hash * hash,unsigned long ip)1155 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1156 {
1157 struct ftrace_func_entry *entry;
1158
1159 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1160 if (!entry)
1161 return -ENOMEM;
1162
1163 entry->ip = ip;
1164 __add_hash_entry(hash, entry);
1165
1166 return 0;
1167 }
1168
1169 static void
free_hash_entry(struct ftrace_hash * hash,struct ftrace_func_entry * entry)1170 free_hash_entry(struct ftrace_hash *hash,
1171 struct ftrace_func_entry *entry)
1172 {
1173 hlist_del(&entry->hlist);
1174 kfree(entry);
1175 hash->count--;
1176 }
1177
1178 static void
remove_hash_entry(struct ftrace_hash * hash,struct ftrace_func_entry * entry)1179 remove_hash_entry(struct ftrace_hash *hash,
1180 struct ftrace_func_entry *entry)
1181 {
1182 hlist_del_rcu(&entry->hlist);
1183 hash->count--;
1184 }
1185
ftrace_hash_clear(struct ftrace_hash * hash)1186 static void ftrace_hash_clear(struct ftrace_hash *hash)
1187 {
1188 struct hlist_head *hhd;
1189 struct hlist_node *tn;
1190 struct ftrace_func_entry *entry;
1191 int size = 1 << hash->size_bits;
1192 int i;
1193
1194 if (!hash->count)
1195 return;
1196
1197 for (i = 0; i < size; i++) {
1198 hhd = &hash->buckets[i];
1199 hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1200 free_hash_entry(hash, entry);
1201 }
1202 FTRACE_WARN_ON(hash->count);
1203 }
1204
free_ftrace_mod(struct ftrace_mod_load * ftrace_mod)1205 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1206 {
1207 list_del(&ftrace_mod->list);
1208 kfree(ftrace_mod->module);
1209 kfree(ftrace_mod->func);
1210 kfree(ftrace_mod);
1211 }
1212
clear_ftrace_mod_list(struct list_head * head)1213 static void clear_ftrace_mod_list(struct list_head *head)
1214 {
1215 struct ftrace_mod_load *p, *n;
1216
1217 /* stack tracer isn't supported yet */
1218 if (!head)
1219 return;
1220
1221 mutex_lock(&ftrace_lock);
1222 list_for_each_entry_safe(p, n, head, list)
1223 free_ftrace_mod(p);
1224 mutex_unlock(&ftrace_lock);
1225 }
1226
free_ftrace_hash(struct ftrace_hash * hash)1227 static void free_ftrace_hash(struct ftrace_hash *hash)
1228 {
1229 if (!hash || hash == EMPTY_HASH)
1230 return;
1231 ftrace_hash_clear(hash);
1232 kfree(hash->buckets);
1233 kfree(hash);
1234 }
1235
__free_ftrace_hash_rcu(struct rcu_head * rcu)1236 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1237 {
1238 struct ftrace_hash *hash;
1239
1240 hash = container_of(rcu, struct ftrace_hash, rcu);
1241 free_ftrace_hash(hash);
1242 }
1243
free_ftrace_hash_rcu(struct ftrace_hash * hash)1244 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1245 {
1246 if (!hash || hash == EMPTY_HASH)
1247 return;
1248 call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1249 }
1250
ftrace_free_filter(struct ftrace_ops * ops)1251 void ftrace_free_filter(struct ftrace_ops *ops)
1252 {
1253 ftrace_ops_init(ops);
1254 free_ftrace_hash(ops->func_hash->filter_hash);
1255 free_ftrace_hash(ops->func_hash->notrace_hash);
1256 }
1257
alloc_ftrace_hash(int size_bits)1258 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1259 {
1260 struct ftrace_hash *hash;
1261 int size;
1262
1263 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1264 if (!hash)
1265 return NULL;
1266
1267 size = 1 << size_bits;
1268 hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1269
1270 if (!hash->buckets) {
1271 kfree(hash);
1272 return NULL;
1273 }
1274
1275 hash->size_bits = size_bits;
1276
1277 return hash;
1278 }
1279
1280
ftrace_add_mod(struct trace_array * tr,const char * func,const char * module,int enable)1281 static int ftrace_add_mod(struct trace_array *tr,
1282 const char *func, const char *module,
1283 int enable)
1284 {
1285 struct ftrace_mod_load *ftrace_mod;
1286 struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1287
1288 ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1289 if (!ftrace_mod)
1290 return -ENOMEM;
1291
1292 INIT_LIST_HEAD(&ftrace_mod->list);
1293 ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1294 ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1295 ftrace_mod->enable = enable;
1296
1297 if (!ftrace_mod->func || !ftrace_mod->module)
1298 goto out_free;
1299
1300 list_add(&ftrace_mod->list, mod_head);
1301
1302 return 0;
1303
1304 out_free:
1305 free_ftrace_mod(ftrace_mod);
1306
1307 return -ENOMEM;
1308 }
1309
1310 static struct ftrace_hash *
alloc_and_copy_ftrace_hash(int size_bits,struct ftrace_hash * hash)1311 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1312 {
1313 struct ftrace_func_entry *entry;
1314 struct ftrace_hash *new_hash;
1315 int size;
1316 int ret;
1317 int i;
1318
1319 new_hash = alloc_ftrace_hash(size_bits);
1320 if (!new_hash)
1321 return NULL;
1322
1323 if (hash)
1324 new_hash->flags = hash->flags;
1325
1326 /* Empty hash? */
1327 if (ftrace_hash_empty(hash))
1328 return new_hash;
1329
1330 size = 1 << hash->size_bits;
1331 for (i = 0; i < size; i++) {
1332 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1333 ret = add_hash_entry(new_hash, entry->ip);
1334 if (ret < 0)
1335 goto free_hash;
1336 }
1337 }
1338
1339 FTRACE_WARN_ON(new_hash->count != hash->count);
1340
1341 return new_hash;
1342
1343 free_hash:
1344 free_ftrace_hash(new_hash);
1345 return NULL;
1346 }
1347
1348 static void
1349 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1350 static void
1351 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1352
1353 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1354 struct ftrace_hash *new_hash);
1355
dup_hash(struct ftrace_hash * src,int size)1356 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1357 {
1358 struct ftrace_func_entry *entry;
1359 struct ftrace_hash *new_hash;
1360 struct hlist_head *hhd;
1361 struct hlist_node *tn;
1362 int bits = 0;
1363 int i;
1364
1365 /*
1366 * Use around half the size (max bit of it), but
1367 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1368 */
1369 bits = fls(size / 2);
1370
1371 /* Don't allocate too much */
1372 if (bits > FTRACE_HASH_MAX_BITS)
1373 bits = FTRACE_HASH_MAX_BITS;
1374
1375 new_hash = alloc_ftrace_hash(bits);
1376 if (!new_hash)
1377 return NULL;
1378
1379 new_hash->flags = src->flags;
1380
1381 size = 1 << src->size_bits;
1382 for (i = 0; i < size; i++) {
1383 hhd = &src->buckets[i];
1384 hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1385 remove_hash_entry(src, entry);
1386 __add_hash_entry(new_hash, entry);
1387 }
1388 }
1389 return new_hash;
1390 }
1391
1392 static struct ftrace_hash *
__ftrace_hash_move(struct ftrace_hash * src)1393 __ftrace_hash_move(struct ftrace_hash *src)
1394 {
1395 int size = src->count;
1396
1397 /*
1398 * If the new source is empty, just return the empty_hash.
1399 */
1400 if (ftrace_hash_empty(src))
1401 return EMPTY_HASH;
1402
1403 return dup_hash(src, size);
1404 }
1405
1406 static int
ftrace_hash_move(struct ftrace_ops * ops,int enable,struct ftrace_hash ** dst,struct ftrace_hash * src)1407 ftrace_hash_move(struct ftrace_ops *ops, int enable,
1408 struct ftrace_hash **dst, struct ftrace_hash *src)
1409 {
1410 struct ftrace_hash *new_hash;
1411 int ret;
1412
1413 /* Reject setting notrace hash on IPMODIFY ftrace_ops */
1414 if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1415 return -EINVAL;
1416
1417 new_hash = __ftrace_hash_move(src);
1418 if (!new_hash)
1419 return -ENOMEM;
1420
1421 /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1422 if (enable) {
1423 /* IPMODIFY should be updated only when filter_hash updating */
1424 ret = ftrace_hash_ipmodify_update(ops, new_hash);
1425 if (ret < 0) {
1426 free_ftrace_hash(new_hash);
1427 return ret;
1428 }
1429 }
1430
1431 /*
1432 * Remove the current set, update the hash and add
1433 * them back.
1434 */
1435 ftrace_hash_rec_disable_modify(ops, enable);
1436
1437 rcu_assign_pointer(*dst, new_hash);
1438
1439 ftrace_hash_rec_enable_modify(ops, enable);
1440
1441 return 0;
1442 }
1443
hash_contains_ip(unsigned long ip,struct ftrace_ops_hash * hash)1444 static bool hash_contains_ip(unsigned long ip,
1445 struct ftrace_ops_hash *hash)
1446 {
1447 /*
1448 * The function record is a match if it exists in the filter
1449 * hash and not in the notrace hash. Note, an empty hash is
1450 * considered a match for the filter hash, but an empty
1451 * notrace hash is considered not in the notrace hash.
1452 */
1453 return (ftrace_hash_empty(hash->filter_hash) ||
1454 __ftrace_lookup_ip(hash->filter_hash, ip)) &&
1455 (ftrace_hash_empty(hash->notrace_hash) ||
1456 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1457 }
1458
1459 /*
1460 * Test the hashes for this ops to see if we want to call
1461 * the ops->func or not.
1462 *
1463 * It's a match if the ip is in the ops->filter_hash or
1464 * the filter_hash does not exist or is empty,
1465 * AND
1466 * the ip is not in the ops->notrace_hash.
1467 *
1468 * This needs to be called with preemption disabled as
1469 * the hashes are freed with call_rcu().
1470 */
1471 int
ftrace_ops_test(struct ftrace_ops * ops,unsigned long ip,void * regs)1472 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1473 {
1474 struct ftrace_ops_hash hash;
1475 int ret;
1476
1477 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1478 /*
1479 * There's a small race when adding ops that the ftrace handler
1480 * that wants regs, may be called without them. We can not
1481 * allow that handler to be called if regs is NULL.
1482 */
1483 if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1484 return 0;
1485 #endif
1486
1487 rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1488 rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1489
1490 if (hash_contains_ip(ip, &hash))
1491 ret = 1;
1492 else
1493 ret = 0;
1494
1495 return ret;
1496 }
1497
1498 /*
1499 * This is a double for. Do not use 'break' to break out of the loop,
1500 * you must use a goto.
1501 */
1502 #define do_for_each_ftrace_rec(pg, rec) \
1503 for (pg = ftrace_pages_start; pg; pg = pg->next) { \
1504 int _____i; \
1505 for (_____i = 0; _____i < pg->index; _____i++) { \
1506 rec = &pg->records[_____i];
1507
1508 #define while_for_each_ftrace_rec() \
1509 } \
1510 }
1511
1512
ftrace_cmp_recs(const void * a,const void * b)1513 static int ftrace_cmp_recs(const void *a, const void *b)
1514 {
1515 const struct dyn_ftrace *key = a;
1516 const struct dyn_ftrace *rec = b;
1517
1518 if (key->flags < rec->ip)
1519 return -1;
1520 if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1521 return 1;
1522 return 0;
1523 }
1524
lookup_rec(unsigned long start,unsigned long end)1525 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1526 {
1527 struct ftrace_page *pg;
1528 struct dyn_ftrace *rec = NULL;
1529 struct dyn_ftrace key;
1530
1531 key.ip = start;
1532 key.flags = end; /* overload flags, as it is unsigned long */
1533
1534 for (pg = ftrace_pages_start; pg; pg = pg->next) {
1535 if (end < pg->records[0].ip ||
1536 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1537 continue;
1538 rec = bsearch(&key, pg->records, pg->index,
1539 sizeof(struct dyn_ftrace),
1540 ftrace_cmp_recs);
1541 if (rec)
1542 break;
1543 }
1544 return rec;
1545 }
1546
1547 /**
1548 * ftrace_location_range - return the first address of a traced location
1549 * if it touches the given ip range
1550 * @start: start of range to search.
1551 * @end: end of range to search (inclusive). @end points to the last byte
1552 * to check.
1553 *
1554 * Returns rec->ip if the related ftrace location is a least partly within
1555 * the given address range. That is, the first address of the instruction
1556 * that is either a NOP or call to the function tracer. It checks the ftrace
1557 * internal tables to determine if the address belongs or not.
1558 */
ftrace_location_range(unsigned long start,unsigned long end)1559 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1560 {
1561 struct dyn_ftrace *rec;
1562
1563 rec = lookup_rec(start, end);
1564 if (rec)
1565 return rec->ip;
1566
1567 return 0;
1568 }
1569
1570 /**
1571 * ftrace_location - return the ftrace location
1572 * @ip: the instruction pointer to check
1573 *
1574 * If @ip matches the ftrace location, return @ip.
1575 * If @ip matches sym+0, return sym's ftrace location.
1576 * Otherwise, return 0.
1577 */
ftrace_location(unsigned long ip)1578 unsigned long ftrace_location(unsigned long ip)
1579 {
1580 struct dyn_ftrace *rec;
1581 unsigned long offset;
1582 unsigned long size;
1583
1584 rec = lookup_rec(ip, ip);
1585 if (!rec) {
1586 if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1587 goto out;
1588
1589 /* map sym+0 to __fentry__ */
1590 if (!offset)
1591 rec = lookup_rec(ip, ip + size - 1);
1592 }
1593
1594 if (rec)
1595 return rec->ip;
1596
1597 out:
1598 return 0;
1599 }
1600
1601 /**
1602 * ftrace_text_reserved - return true if range contains an ftrace location
1603 * @start: start of range to search
1604 * @end: end of range to search (inclusive). @end points to the last byte to check.
1605 *
1606 * Returns 1 if @start and @end contains a ftrace location.
1607 * That is, the instruction that is either a NOP or call to
1608 * the function tracer. It checks the ftrace internal tables to
1609 * determine if the address belongs or not.
1610 */
ftrace_text_reserved(const void * start,const void * end)1611 int ftrace_text_reserved(const void *start, const void *end)
1612 {
1613 unsigned long ret;
1614
1615 ret = ftrace_location_range((unsigned long)start,
1616 (unsigned long)end);
1617
1618 return (int)!!ret;
1619 }
1620
1621 /* Test if ops registered to this rec needs regs */
test_rec_ops_needs_regs(struct dyn_ftrace * rec)1622 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1623 {
1624 struct ftrace_ops *ops;
1625 bool keep_regs = false;
1626
1627 for (ops = ftrace_ops_list;
1628 ops != &ftrace_list_end; ops = ops->next) {
1629 /* pass rec in as regs to have non-NULL val */
1630 if (ftrace_ops_test(ops, rec->ip, rec)) {
1631 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1632 keep_regs = true;
1633 break;
1634 }
1635 }
1636 }
1637
1638 return keep_regs;
1639 }
1640
1641 static struct ftrace_ops *
1642 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1643 static struct ftrace_ops *
1644 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1645 static struct ftrace_ops *
1646 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1647
skip_record(struct dyn_ftrace * rec)1648 static bool skip_record(struct dyn_ftrace *rec)
1649 {
1650 /*
1651 * At boot up, weak functions are set to disable. Function tracing
1652 * can be enabled before they are, and they still need to be disabled now.
1653 * If the record is disabled, still continue if it is marked as already
1654 * enabled (this is needed to keep the accounting working).
1655 */
1656 return rec->flags & FTRACE_FL_DISABLED &&
1657 !(rec->flags & FTRACE_FL_ENABLED);
1658 }
1659
__ftrace_hash_rec_update(struct ftrace_ops * ops,int filter_hash,bool inc)1660 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1661 int filter_hash,
1662 bool inc)
1663 {
1664 struct ftrace_hash *hash;
1665 struct ftrace_hash *other_hash;
1666 struct ftrace_page *pg;
1667 struct dyn_ftrace *rec;
1668 bool update = false;
1669 int count = 0;
1670 int all = false;
1671
1672 /* Only update if the ops has been registered */
1673 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1674 return false;
1675
1676 /*
1677 * In the filter_hash case:
1678 * If the count is zero, we update all records.
1679 * Otherwise we just update the items in the hash.
1680 *
1681 * In the notrace_hash case:
1682 * We enable the update in the hash.
1683 * As disabling notrace means enabling the tracing,
1684 * and enabling notrace means disabling, the inc variable
1685 * gets inversed.
1686 */
1687 if (filter_hash) {
1688 hash = ops->func_hash->filter_hash;
1689 other_hash = ops->func_hash->notrace_hash;
1690 if (ftrace_hash_empty(hash))
1691 all = true;
1692 } else {
1693 inc = !inc;
1694 hash = ops->func_hash->notrace_hash;
1695 other_hash = ops->func_hash->filter_hash;
1696 /*
1697 * If the notrace hash has no items,
1698 * then there's nothing to do.
1699 */
1700 if (ftrace_hash_empty(hash))
1701 return false;
1702 }
1703
1704 do_for_each_ftrace_rec(pg, rec) {
1705 int in_other_hash = 0;
1706 int in_hash = 0;
1707 int match = 0;
1708
1709 if (skip_record(rec))
1710 continue;
1711
1712 if (all) {
1713 /*
1714 * Only the filter_hash affects all records.
1715 * Update if the record is not in the notrace hash.
1716 */
1717 if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1718 match = 1;
1719 } else {
1720 in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1721 in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1722
1723 /*
1724 * If filter_hash is set, we want to match all functions
1725 * that are in the hash but not in the other hash.
1726 *
1727 * If filter_hash is not set, then we are decrementing.
1728 * That means we match anything that is in the hash
1729 * and also in the other_hash. That is, we need to turn
1730 * off functions in the other hash because they are disabled
1731 * by this hash.
1732 */
1733 if (filter_hash && in_hash && !in_other_hash)
1734 match = 1;
1735 else if (!filter_hash && in_hash &&
1736 (in_other_hash || ftrace_hash_empty(other_hash)))
1737 match = 1;
1738 }
1739 if (!match)
1740 continue;
1741
1742 if (inc) {
1743 rec->flags++;
1744 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1745 return false;
1746
1747 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1748 rec->flags |= FTRACE_FL_DIRECT;
1749
1750 /*
1751 * If there's only a single callback registered to a
1752 * function, and the ops has a trampoline registered
1753 * for it, then we can call it directly.
1754 */
1755 if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1756 rec->flags |= FTRACE_FL_TRAMP;
1757 else
1758 /*
1759 * If we are adding another function callback
1760 * to this function, and the previous had a
1761 * custom trampoline in use, then we need to go
1762 * back to the default trampoline.
1763 */
1764 rec->flags &= ~FTRACE_FL_TRAMP;
1765
1766 /*
1767 * If any ops wants regs saved for this function
1768 * then all ops will get saved regs.
1769 */
1770 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1771 rec->flags |= FTRACE_FL_REGS;
1772 } else {
1773 if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1774 return false;
1775 rec->flags--;
1776
1777 /*
1778 * Only the internal direct_ops should have the
1779 * DIRECT flag set. Thus, if it is removing a
1780 * function, then that function should no longer
1781 * be direct.
1782 */
1783 if (ops->flags & FTRACE_OPS_FL_DIRECT)
1784 rec->flags &= ~FTRACE_FL_DIRECT;
1785
1786 /*
1787 * If the rec had REGS enabled and the ops that is
1788 * being removed had REGS set, then see if there is
1789 * still any ops for this record that wants regs.
1790 * If not, we can stop recording them.
1791 */
1792 if (ftrace_rec_count(rec) > 0 &&
1793 rec->flags & FTRACE_FL_REGS &&
1794 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1795 if (!test_rec_ops_needs_regs(rec))
1796 rec->flags &= ~FTRACE_FL_REGS;
1797 }
1798
1799 /*
1800 * The TRAMP needs to be set only if rec count
1801 * is decremented to one, and the ops that is
1802 * left has a trampoline. As TRAMP can only be
1803 * enabled if there is only a single ops attached
1804 * to it.
1805 */
1806 if (ftrace_rec_count(rec) == 1 &&
1807 ftrace_find_tramp_ops_any_other(rec, ops))
1808 rec->flags |= FTRACE_FL_TRAMP;
1809 else
1810 rec->flags &= ~FTRACE_FL_TRAMP;
1811
1812 /*
1813 * flags will be cleared in ftrace_check_record()
1814 * if rec count is zero.
1815 */
1816 }
1817 count++;
1818
1819 /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1820 update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1821
1822 /* Shortcut, if we handled all records, we are done. */
1823 if (!all && count == hash->count)
1824 return update;
1825 } while_for_each_ftrace_rec();
1826
1827 return update;
1828 }
1829
ftrace_hash_rec_disable(struct ftrace_ops * ops,int filter_hash)1830 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1831 int filter_hash)
1832 {
1833 return __ftrace_hash_rec_update(ops, filter_hash, 0);
1834 }
1835
ftrace_hash_rec_enable(struct ftrace_ops * ops,int filter_hash)1836 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1837 int filter_hash)
1838 {
1839 return __ftrace_hash_rec_update(ops, filter_hash, 1);
1840 }
1841
ftrace_hash_rec_update_modify(struct ftrace_ops * ops,int filter_hash,int inc)1842 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1843 int filter_hash, int inc)
1844 {
1845 struct ftrace_ops *op;
1846
1847 __ftrace_hash_rec_update(ops, filter_hash, inc);
1848
1849 if (ops->func_hash != &global_ops.local_hash)
1850 return;
1851
1852 /*
1853 * If the ops shares the global_ops hash, then we need to update
1854 * all ops that are enabled and use this hash.
1855 */
1856 do_for_each_ftrace_op(op, ftrace_ops_list) {
1857 /* Already done */
1858 if (op == ops)
1859 continue;
1860 if (op->func_hash == &global_ops.local_hash)
1861 __ftrace_hash_rec_update(op, filter_hash, inc);
1862 } while_for_each_ftrace_op(op);
1863 }
1864
ftrace_hash_rec_disable_modify(struct ftrace_ops * ops,int filter_hash)1865 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1866 int filter_hash)
1867 {
1868 ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1869 }
1870
ftrace_hash_rec_enable_modify(struct ftrace_ops * ops,int filter_hash)1871 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1872 int filter_hash)
1873 {
1874 ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1875 }
1876
1877 /*
1878 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1879 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1880 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1881 * Note that old_hash and new_hash has below meanings
1882 * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1883 * - If the hash is EMPTY_HASH, it hits nothing
1884 * - Anything else hits the recs which match the hash entries.
1885 *
1886 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1887 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1888 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1889 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1890 * the return value to the caller and eventually to the owner of the DIRECT
1891 * ops.
1892 */
__ftrace_hash_update_ipmodify(struct ftrace_ops * ops,struct ftrace_hash * old_hash,struct ftrace_hash * new_hash)1893 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1894 struct ftrace_hash *old_hash,
1895 struct ftrace_hash *new_hash)
1896 {
1897 struct ftrace_page *pg;
1898 struct dyn_ftrace *rec, *end = NULL;
1899 int in_old, in_new;
1900 bool is_ipmodify, is_direct;
1901
1902 /* Only update if the ops has been registered */
1903 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1904 return 0;
1905
1906 is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1907 is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1908
1909 /* neither IPMODIFY nor DIRECT, skip */
1910 if (!is_ipmodify && !is_direct)
1911 return 0;
1912
1913 if (WARN_ON_ONCE(is_ipmodify && is_direct))
1914 return 0;
1915
1916 /*
1917 * Since the IPMODIFY and DIRECT are very address sensitive
1918 * actions, we do not allow ftrace_ops to set all functions to new
1919 * hash.
1920 */
1921 if (!new_hash || !old_hash)
1922 return -EINVAL;
1923
1924 /* Update rec->flags */
1925 do_for_each_ftrace_rec(pg, rec) {
1926
1927 if (rec->flags & FTRACE_FL_DISABLED)
1928 continue;
1929
1930 /* We need to update only differences of filter_hash */
1931 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1932 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1933 if (in_old == in_new)
1934 continue;
1935
1936 if (in_new) {
1937 if (rec->flags & FTRACE_FL_IPMODIFY) {
1938 int ret;
1939
1940 /* Cannot have two ipmodify on same rec */
1941 if (is_ipmodify)
1942 goto rollback;
1943
1944 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1945
1946 /*
1947 * Another ops with IPMODIFY is already
1948 * attached. We are now attaching a direct
1949 * ops. Run SHARE_IPMODIFY_SELF, to check
1950 * whether sharing is supported.
1951 */
1952 if (!ops->ops_func)
1953 return -EBUSY;
1954 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
1955 if (ret)
1956 return ret;
1957 } else if (is_ipmodify) {
1958 rec->flags |= FTRACE_FL_IPMODIFY;
1959 }
1960 } else if (is_ipmodify) {
1961 rec->flags &= ~FTRACE_FL_IPMODIFY;
1962 }
1963 } while_for_each_ftrace_rec();
1964
1965 return 0;
1966
1967 rollback:
1968 end = rec;
1969
1970 /* Roll back what we did above */
1971 do_for_each_ftrace_rec(pg, rec) {
1972
1973 if (rec->flags & FTRACE_FL_DISABLED)
1974 continue;
1975
1976 if (rec == end)
1977 goto err_out;
1978
1979 in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1980 in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1981 if (in_old == in_new)
1982 continue;
1983
1984 if (in_new)
1985 rec->flags &= ~FTRACE_FL_IPMODIFY;
1986 else
1987 rec->flags |= FTRACE_FL_IPMODIFY;
1988 } while_for_each_ftrace_rec();
1989
1990 err_out:
1991 return -EBUSY;
1992 }
1993
ftrace_hash_ipmodify_enable(struct ftrace_ops * ops)1994 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1995 {
1996 struct ftrace_hash *hash = ops->func_hash->filter_hash;
1997
1998 if (ftrace_hash_empty(hash))
1999 hash = NULL;
2000
2001 return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2002 }
2003
2004 /* Disabling always succeeds */
ftrace_hash_ipmodify_disable(struct ftrace_ops * ops)2005 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2006 {
2007 struct ftrace_hash *hash = ops->func_hash->filter_hash;
2008
2009 if (ftrace_hash_empty(hash))
2010 hash = NULL;
2011
2012 __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2013 }
2014
ftrace_hash_ipmodify_update(struct ftrace_ops * ops,struct ftrace_hash * new_hash)2015 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2016 struct ftrace_hash *new_hash)
2017 {
2018 struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2019
2020 if (ftrace_hash_empty(old_hash))
2021 old_hash = NULL;
2022
2023 if (ftrace_hash_empty(new_hash))
2024 new_hash = NULL;
2025
2026 return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2027 }
2028
print_ip_ins(const char * fmt,const unsigned char * p)2029 static void print_ip_ins(const char *fmt, const unsigned char *p)
2030 {
2031 char ins[MCOUNT_INSN_SIZE];
2032
2033 if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2034 printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2035 return;
2036 }
2037
2038 printk(KERN_CONT "%s", fmt);
2039 pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2040 }
2041
2042 enum ftrace_bug_type ftrace_bug_type;
2043 const void *ftrace_expected;
2044
print_bug_type(void)2045 static void print_bug_type(void)
2046 {
2047 switch (ftrace_bug_type) {
2048 case FTRACE_BUG_UNKNOWN:
2049 break;
2050 case FTRACE_BUG_INIT:
2051 pr_info("Initializing ftrace call sites\n");
2052 break;
2053 case FTRACE_BUG_NOP:
2054 pr_info("Setting ftrace call site to NOP\n");
2055 break;
2056 case FTRACE_BUG_CALL:
2057 pr_info("Setting ftrace call site to call ftrace function\n");
2058 break;
2059 case FTRACE_BUG_UPDATE:
2060 pr_info("Updating ftrace call site to call a different ftrace function\n");
2061 break;
2062 }
2063 }
2064
2065 /**
2066 * ftrace_bug - report and shutdown function tracer
2067 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2068 * @rec: The record that failed
2069 *
2070 * The arch code that enables or disables the function tracing
2071 * can call ftrace_bug() when it has detected a problem in
2072 * modifying the code. @failed should be one of either:
2073 * EFAULT - if the problem happens on reading the @ip address
2074 * EINVAL - if what is read at @ip is not what was expected
2075 * EPERM - if the problem happens on writing to the @ip address
2076 */
ftrace_bug(int failed,struct dyn_ftrace * rec)2077 void ftrace_bug(int failed, struct dyn_ftrace *rec)
2078 {
2079 unsigned long ip = rec ? rec->ip : 0;
2080
2081 pr_info("------------[ ftrace bug ]------------\n");
2082
2083 switch (failed) {
2084 case -EFAULT:
2085 pr_info("ftrace faulted on modifying ");
2086 print_ip_sym(KERN_INFO, ip);
2087 break;
2088 case -EINVAL:
2089 pr_info("ftrace failed to modify ");
2090 print_ip_sym(KERN_INFO, ip);
2091 print_ip_ins(" actual: ", (unsigned char *)ip);
2092 pr_cont("\n");
2093 if (ftrace_expected) {
2094 print_ip_ins(" expected: ", ftrace_expected);
2095 pr_cont("\n");
2096 }
2097 break;
2098 case -EPERM:
2099 pr_info("ftrace faulted on writing ");
2100 print_ip_sym(KERN_INFO, ip);
2101 break;
2102 default:
2103 pr_info("ftrace faulted on unknown error ");
2104 print_ip_sym(KERN_INFO, ip);
2105 }
2106 print_bug_type();
2107 if (rec) {
2108 struct ftrace_ops *ops = NULL;
2109
2110 pr_info("ftrace record flags: %lx\n", rec->flags);
2111 pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2112 rec->flags & FTRACE_FL_REGS ? " R" : " ");
2113 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2114 ops = ftrace_find_tramp_ops_any(rec);
2115 if (ops) {
2116 do {
2117 pr_cont("\ttramp: %pS (%pS)",
2118 (void *)ops->trampoline,
2119 (void *)ops->func);
2120 ops = ftrace_find_tramp_ops_next(rec, ops);
2121 } while (ops);
2122 } else
2123 pr_cont("\ttramp: ERROR!");
2124
2125 }
2126 ip = ftrace_get_addr_curr(rec);
2127 pr_cont("\n expected tramp: %lx\n", ip);
2128 }
2129
2130 FTRACE_WARN_ON_ONCE(1);
2131 }
2132
ftrace_check_record(struct dyn_ftrace * rec,bool enable,bool update)2133 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2134 {
2135 unsigned long flag = 0UL;
2136
2137 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2138
2139 if (skip_record(rec))
2140 return FTRACE_UPDATE_IGNORE;
2141
2142 /*
2143 * If we are updating calls:
2144 *
2145 * If the record has a ref count, then we need to enable it
2146 * because someone is using it.
2147 *
2148 * Otherwise we make sure its disabled.
2149 *
2150 * If we are disabling calls, then disable all records that
2151 * are enabled.
2152 */
2153 if (enable && ftrace_rec_count(rec))
2154 flag = FTRACE_FL_ENABLED;
2155
2156 /*
2157 * If enabling and the REGS flag does not match the REGS_EN, or
2158 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2159 * this record. Set flags to fail the compare against ENABLED.
2160 * Same for direct calls.
2161 */
2162 if (flag) {
2163 if (!(rec->flags & FTRACE_FL_REGS) !=
2164 !(rec->flags & FTRACE_FL_REGS_EN))
2165 flag |= FTRACE_FL_REGS;
2166
2167 if (!(rec->flags & FTRACE_FL_TRAMP) !=
2168 !(rec->flags & FTRACE_FL_TRAMP_EN))
2169 flag |= FTRACE_FL_TRAMP;
2170
2171 /*
2172 * Direct calls are special, as count matters.
2173 * We must test the record for direct, if the
2174 * DIRECT and DIRECT_EN do not match, but only
2175 * if the count is 1. That's because, if the
2176 * count is something other than one, we do not
2177 * want the direct enabled (it will be done via the
2178 * direct helper). But if DIRECT_EN is set, and
2179 * the count is not one, we need to clear it.
2180 */
2181 if (ftrace_rec_count(rec) == 1) {
2182 if (!(rec->flags & FTRACE_FL_DIRECT) !=
2183 !(rec->flags & FTRACE_FL_DIRECT_EN))
2184 flag |= FTRACE_FL_DIRECT;
2185 } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2186 flag |= FTRACE_FL_DIRECT;
2187 }
2188 }
2189
2190 /* If the state of this record hasn't changed, then do nothing */
2191 if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2192 return FTRACE_UPDATE_IGNORE;
2193
2194 if (flag) {
2195 /* Save off if rec is being enabled (for return value) */
2196 flag ^= rec->flags & FTRACE_FL_ENABLED;
2197
2198 if (update) {
2199 rec->flags |= FTRACE_FL_ENABLED;
2200 if (flag & FTRACE_FL_REGS) {
2201 if (rec->flags & FTRACE_FL_REGS)
2202 rec->flags |= FTRACE_FL_REGS_EN;
2203 else
2204 rec->flags &= ~FTRACE_FL_REGS_EN;
2205 }
2206 if (flag & FTRACE_FL_TRAMP) {
2207 if (rec->flags & FTRACE_FL_TRAMP)
2208 rec->flags |= FTRACE_FL_TRAMP_EN;
2209 else
2210 rec->flags &= ~FTRACE_FL_TRAMP_EN;
2211 }
2212
2213 if (flag & FTRACE_FL_DIRECT) {
2214 /*
2215 * If there's only one user (direct_ops helper)
2216 * then we can call the direct function
2217 * directly (no ftrace trampoline).
2218 */
2219 if (ftrace_rec_count(rec) == 1) {
2220 if (rec->flags & FTRACE_FL_DIRECT)
2221 rec->flags |= FTRACE_FL_DIRECT_EN;
2222 else
2223 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2224 } else {
2225 /*
2226 * Can only call directly if there's
2227 * only one callback to the function.
2228 */
2229 rec->flags &= ~FTRACE_FL_DIRECT_EN;
2230 }
2231 }
2232 }
2233
2234 /*
2235 * If this record is being updated from a nop, then
2236 * return UPDATE_MAKE_CALL.
2237 * Otherwise,
2238 * return UPDATE_MODIFY_CALL to tell the caller to convert
2239 * from the save regs, to a non-save regs function or
2240 * vice versa, or from a trampoline call.
2241 */
2242 if (flag & FTRACE_FL_ENABLED) {
2243 ftrace_bug_type = FTRACE_BUG_CALL;
2244 return FTRACE_UPDATE_MAKE_CALL;
2245 }
2246
2247 ftrace_bug_type = FTRACE_BUG_UPDATE;
2248 return FTRACE_UPDATE_MODIFY_CALL;
2249 }
2250
2251 if (update) {
2252 /* If there's no more users, clear all flags */
2253 if (!ftrace_rec_count(rec))
2254 rec->flags &= FTRACE_FL_DISABLED;
2255 else
2256 /*
2257 * Just disable the record, but keep the ops TRAMP
2258 * and REGS states. The _EN flags must be disabled though.
2259 */
2260 rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2261 FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2262 }
2263
2264 ftrace_bug_type = FTRACE_BUG_NOP;
2265 return FTRACE_UPDATE_MAKE_NOP;
2266 }
2267
2268 /**
2269 * ftrace_update_record - set a record that now is tracing or not
2270 * @rec: the record to update
2271 * @enable: set to true if the record is tracing, false to force disable
2272 *
2273 * The records that represent all functions that can be traced need
2274 * to be updated when tracing has been enabled.
2275 */
ftrace_update_record(struct dyn_ftrace * rec,bool enable)2276 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2277 {
2278 return ftrace_check_record(rec, enable, true);
2279 }
2280
2281 /**
2282 * ftrace_test_record - check if the record has been enabled or not
2283 * @rec: the record to test
2284 * @enable: set to true to check if enabled, false if it is disabled
2285 *
2286 * The arch code may need to test if a record is already set to
2287 * tracing to determine how to modify the function code that it
2288 * represents.
2289 */
ftrace_test_record(struct dyn_ftrace * rec,bool enable)2290 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2291 {
2292 return ftrace_check_record(rec, enable, false);
2293 }
2294
2295 static struct ftrace_ops *
ftrace_find_tramp_ops_any(struct dyn_ftrace * rec)2296 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2297 {
2298 struct ftrace_ops *op;
2299 unsigned long ip = rec->ip;
2300
2301 do_for_each_ftrace_op(op, ftrace_ops_list) {
2302
2303 if (!op->trampoline)
2304 continue;
2305
2306 if (hash_contains_ip(ip, op->func_hash))
2307 return op;
2308 } while_for_each_ftrace_op(op);
2309
2310 return NULL;
2311 }
2312
2313 static struct ftrace_ops *
ftrace_find_tramp_ops_any_other(struct dyn_ftrace * rec,struct ftrace_ops * op_exclude)2314 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2315 {
2316 struct ftrace_ops *op;
2317 unsigned long ip = rec->ip;
2318
2319 do_for_each_ftrace_op(op, ftrace_ops_list) {
2320
2321 if (op == op_exclude || !op->trampoline)
2322 continue;
2323
2324 if (hash_contains_ip(ip, op->func_hash))
2325 return op;
2326 } while_for_each_ftrace_op(op);
2327
2328 return NULL;
2329 }
2330
2331 static struct ftrace_ops *
ftrace_find_tramp_ops_next(struct dyn_ftrace * rec,struct ftrace_ops * op)2332 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2333 struct ftrace_ops *op)
2334 {
2335 unsigned long ip = rec->ip;
2336
2337 while_for_each_ftrace_op(op) {
2338
2339 if (!op->trampoline)
2340 continue;
2341
2342 if (hash_contains_ip(ip, op->func_hash))
2343 return op;
2344 }
2345
2346 return NULL;
2347 }
2348
2349 static struct ftrace_ops *
ftrace_find_tramp_ops_curr(struct dyn_ftrace * rec)2350 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2351 {
2352 struct ftrace_ops *op;
2353 unsigned long ip = rec->ip;
2354
2355 /*
2356 * Need to check removed ops first.
2357 * If they are being removed, and this rec has a tramp,
2358 * and this rec is in the ops list, then it would be the
2359 * one with the tramp.
2360 */
2361 if (removed_ops) {
2362 if (hash_contains_ip(ip, &removed_ops->old_hash))
2363 return removed_ops;
2364 }
2365
2366 /*
2367 * Need to find the current trampoline for a rec.
2368 * Now, a trampoline is only attached to a rec if there
2369 * was a single 'ops' attached to it. But this can be called
2370 * when we are adding another op to the rec or removing the
2371 * current one. Thus, if the op is being added, we can
2372 * ignore it because it hasn't attached itself to the rec
2373 * yet.
2374 *
2375 * If an ops is being modified (hooking to different functions)
2376 * then we don't care about the new functions that are being
2377 * added, just the old ones (that are probably being removed).
2378 *
2379 * If we are adding an ops to a function that already is using
2380 * a trampoline, it needs to be removed (trampolines are only
2381 * for single ops connected), then an ops that is not being
2382 * modified also needs to be checked.
2383 */
2384 do_for_each_ftrace_op(op, ftrace_ops_list) {
2385
2386 if (!op->trampoline)
2387 continue;
2388
2389 /*
2390 * If the ops is being added, it hasn't gotten to
2391 * the point to be removed from this tree yet.
2392 */
2393 if (op->flags & FTRACE_OPS_FL_ADDING)
2394 continue;
2395
2396
2397 /*
2398 * If the ops is being modified and is in the old
2399 * hash, then it is probably being removed from this
2400 * function.
2401 */
2402 if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2403 hash_contains_ip(ip, &op->old_hash))
2404 return op;
2405 /*
2406 * If the ops is not being added or modified, and it's
2407 * in its normal filter hash, then this must be the one
2408 * we want!
2409 */
2410 if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2411 hash_contains_ip(ip, op->func_hash))
2412 return op;
2413
2414 } while_for_each_ftrace_op(op);
2415
2416 return NULL;
2417 }
2418
2419 static struct ftrace_ops *
ftrace_find_tramp_ops_new(struct dyn_ftrace * rec)2420 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2421 {
2422 struct ftrace_ops *op;
2423 unsigned long ip = rec->ip;
2424
2425 do_for_each_ftrace_op(op, ftrace_ops_list) {
2426 /* pass rec in as regs to have non-NULL val */
2427 if (hash_contains_ip(ip, op->func_hash))
2428 return op;
2429 } while_for_each_ftrace_op(op);
2430
2431 return NULL;
2432 }
2433
2434 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2435 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
2436 static struct ftrace_hash *direct_functions = EMPTY_HASH;
2437 static DEFINE_MUTEX(direct_mutex);
2438 int ftrace_direct_func_count;
2439
2440 /*
2441 * Search the direct_functions hash to see if the given instruction pointer
2442 * has a direct caller attached to it.
2443 */
ftrace_find_rec_direct(unsigned long ip)2444 unsigned long ftrace_find_rec_direct(unsigned long ip)
2445 {
2446 struct ftrace_func_entry *entry;
2447
2448 entry = __ftrace_lookup_ip(direct_functions, ip);
2449 if (!entry)
2450 return 0;
2451
2452 return entry->direct;
2453 }
2454
2455 static struct ftrace_func_entry*
ftrace_add_rec_direct(unsigned long ip,unsigned long addr,struct ftrace_hash ** free_hash)2456 ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
2457 struct ftrace_hash **free_hash)
2458 {
2459 struct ftrace_func_entry *entry;
2460
2461 if (ftrace_hash_empty(direct_functions) ||
2462 direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
2463 struct ftrace_hash *new_hash;
2464 int size = ftrace_hash_empty(direct_functions) ? 0 :
2465 direct_functions->count + 1;
2466
2467 if (size < 32)
2468 size = 32;
2469
2470 new_hash = dup_hash(direct_functions, size);
2471 if (!new_hash)
2472 return NULL;
2473
2474 *free_hash = direct_functions;
2475 direct_functions = new_hash;
2476 }
2477
2478 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2479 if (!entry)
2480 return NULL;
2481
2482 entry->ip = ip;
2483 entry->direct = addr;
2484 __add_hash_entry(direct_functions, entry);
2485 return entry;
2486 }
2487
call_direct_funcs(unsigned long ip,unsigned long pip,struct ftrace_ops * ops,struct ftrace_regs * fregs)2488 static void call_direct_funcs(unsigned long ip, unsigned long pip,
2489 struct ftrace_ops *ops, struct ftrace_regs *fregs)
2490 {
2491 struct pt_regs *regs = ftrace_get_regs(fregs);
2492 unsigned long addr;
2493
2494 addr = ftrace_find_rec_direct(ip);
2495 if (!addr)
2496 return;
2497
2498 arch_ftrace_set_direct_caller(regs, addr);
2499 }
2500
2501 struct ftrace_ops direct_ops = {
2502 .func = call_direct_funcs,
2503 .flags = FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
2504 | FTRACE_OPS_FL_PERMANENT,
2505 /*
2506 * By declaring the main trampoline as this trampoline
2507 * it will never have one allocated for it. Allocated
2508 * trampolines should not call direct functions.
2509 * The direct_ops should only be called by the builtin
2510 * ftrace_regs_caller trampoline.
2511 */
2512 .trampoline = FTRACE_REGS_ADDR,
2513 };
2514 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2515
2516 /**
2517 * ftrace_get_addr_new - Get the call address to set to
2518 * @rec: The ftrace record descriptor
2519 *
2520 * If the record has the FTRACE_FL_REGS set, that means that it
2521 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2522 * is not set, then it wants to convert to the normal callback.
2523 *
2524 * Returns the address of the trampoline to set to
2525 */
ftrace_get_addr_new(struct dyn_ftrace * rec)2526 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2527 {
2528 struct ftrace_ops *ops;
2529 unsigned long addr;
2530
2531 if ((rec->flags & FTRACE_FL_DIRECT) &&
2532 (ftrace_rec_count(rec) == 1)) {
2533 addr = ftrace_find_rec_direct(rec->ip);
2534 if (addr)
2535 return addr;
2536 WARN_ON_ONCE(1);
2537 }
2538
2539 /* Trampolines take precedence over regs */
2540 if (rec->flags & FTRACE_FL_TRAMP) {
2541 ops = ftrace_find_tramp_ops_new(rec);
2542 if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2543 pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2544 (void *)rec->ip, (void *)rec->ip, rec->flags);
2545 /* Ftrace is shutting down, return anything */
2546 return (unsigned long)FTRACE_ADDR;
2547 }
2548 return ops->trampoline;
2549 }
2550
2551 if (rec->flags & FTRACE_FL_REGS)
2552 return (unsigned long)FTRACE_REGS_ADDR;
2553 else
2554 return (unsigned long)FTRACE_ADDR;
2555 }
2556
2557 /**
2558 * ftrace_get_addr_curr - Get the call address that is already there
2559 * @rec: The ftrace record descriptor
2560 *
2561 * The FTRACE_FL_REGS_EN is set when the record already points to
2562 * a function that saves all the regs. Basically the '_EN' version
2563 * represents the current state of the function.
2564 *
2565 * Returns the address of the trampoline that is currently being called
2566 */
ftrace_get_addr_curr(struct dyn_ftrace * rec)2567 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2568 {
2569 struct ftrace_ops *ops;
2570 unsigned long addr;
2571
2572 /* Direct calls take precedence over trampolines */
2573 if (rec->flags & FTRACE_FL_DIRECT_EN) {
2574 addr = ftrace_find_rec_direct(rec->ip);
2575 if (addr)
2576 return addr;
2577 WARN_ON_ONCE(1);
2578 }
2579
2580 /* Trampolines take precedence over regs */
2581 if (rec->flags & FTRACE_FL_TRAMP_EN) {
2582 ops = ftrace_find_tramp_ops_curr(rec);
2583 if (FTRACE_WARN_ON(!ops)) {
2584 pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2585 (void *)rec->ip, (void *)rec->ip);
2586 /* Ftrace is shutting down, return anything */
2587 return (unsigned long)FTRACE_ADDR;
2588 }
2589 return ops->trampoline;
2590 }
2591
2592 if (rec->flags & FTRACE_FL_REGS_EN)
2593 return (unsigned long)FTRACE_REGS_ADDR;
2594 else
2595 return (unsigned long)FTRACE_ADDR;
2596 }
2597
2598 static int
__ftrace_replace_code(struct dyn_ftrace * rec,bool enable)2599 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2600 {
2601 unsigned long ftrace_old_addr;
2602 unsigned long ftrace_addr;
2603 int ret;
2604
2605 ftrace_addr = ftrace_get_addr_new(rec);
2606
2607 /* This needs to be done before we call ftrace_update_record */
2608 ftrace_old_addr = ftrace_get_addr_curr(rec);
2609
2610 ret = ftrace_update_record(rec, enable);
2611
2612 ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2613
2614 switch (ret) {
2615 case FTRACE_UPDATE_IGNORE:
2616 return 0;
2617
2618 case FTRACE_UPDATE_MAKE_CALL:
2619 ftrace_bug_type = FTRACE_BUG_CALL;
2620 return ftrace_make_call(rec, ftrace_addr);
2621
2622 case FTRACE_UPDATE_MAKE_NOP:
2623 ftrace_bug_type = FTRACE_BUG_NOP;
2624 return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2625
2626 case FTRACE_UPDATE_MODIFY_CALL:
2627 ftrace_bug_type = FTRACE_BUG_UPDATE;
2628 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2629 }
2630
2631 return -1; /* unknown ftrace bug */
2632 }
2633
ftrace_replace_code(int mod_flags)2634 void __weak ftrace_replace_code(int mod_flags)
2635 {
2636 struct dyn_ftrace *rec;
2637 struct ftrace_page *pg;
2638 bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2639 int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2640 int failed;
2641
2642 if (unlikely(ftrace_disabled))
2643 return;
2644
2645 do_for_each_ftrace_rec(pg, rec) {
2646
2647 if (skip_record(rec))
2648 continue;
2649
2650 failed = __ftrace_replace_code(rec, enable);
2651 if (failed) {
2652 ftrace_bug(failed, rec);
2653 /* Stop processing */
2654 return;
2655 }
2656 if (schedulable)
2657 cond_resched();
2658 } while_for_each_ftrace_rec();
2659 }
2660
2661 struct ftrace_rec_iter {
2662 struct ftrace_page *pg;
2663 int index;
2664 };
2665
2666 /**
2667 * ftrace_rec_iter_start - start up iterating over traced functions
2668 *
2669 * Returns an iterator handle that is used to iterate over all
2670 * the records that represent address locations where functions
2671 * are traced.
2672 *
2673 * May return NULL if no records are available.
2674 */
ftrace_rec_iter_start(void)2675 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2676 {
2677 /*
2678 * We only use a single iterator.
2679 * Protected by the ftrace_lock mutex.
2680 */
2681 static struct ftrace_rec_iter ftrace_rec_iter;
2682 struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2683
2684 iter->pg = ftrace_pages_start;
2685 iter->index = 0;
2686
2687 /* Could have empty pages */
2688 while (iter->pg && !iter->pg->index)
2689 iter->pg = iter->pg->next;
2690
2691 if (!iter->pg)
2692 return NULL;
2693
2694 return iter;
2695 }
2696
2697 /**
2698 * ftrace_rec_iter_next - get the next record to process.
2699 * @iter: The handle to the iterator.
2700 *
2701 * Returns the next iterator after the given iterator @iter.
2702 */
ftrace_rec_iter_next(struct ftrace_rec_iter * iter)2703 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2704 {
2705 iter->index++;
2706
2707 if (iter->index >= iter->pg->index) {
2708 iter->pg = iter->pg->next;
2709 iter->index = 0;
2710
2711 /* Could have empty pages */
2712 while (iter->pg && !iter->pg->index)
2713 iter->pg = iter->pg->next;
2714 }
2715
2716 if (!iter->pg)
2717 return NULL;
2718
2719 return iter;
2720 }
2721
2722 /**
2723 * ftrace_rec_iter_record - get the record at the iterator location
2724 * @iter: The current iterator location
2725 *
2726 * Returns the record that the current @iter is at.
2727 */
ftrace_rec_iter_record(struct ftrace_rec_iter * iter)2728 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2729 {
2730 return &iter->pg->records[iter->index];
2731 }
2732
2733 static int
ftrace_nop_initialize(struct module * mod,struct dyn_ftrace * rec)2734 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2735 {
2736 int ret;
2737
2738 if (unlikely(ftrace_disabled))
2739 return 0;
2740
2741 ret = ftrace_init_nop(mod, rec);
2742 if (ret) {
2743 ftrace_bug_type = FTRACE_BUG_INIT;
2744 ftrace_bug(ret, rec);
2745 return 0;
2746 }
2747 return 1;
2748 }
2749
2750 /*
2751 * archs can override this function if they must do something
2752 * before the modifying code is performed.
2753 */
ftrace_arch_code_modify_prepare(void)2754 void __weak ftrace_arch_code_modify_prepare(void)
2755 {
2756 }
2757
2758 /*
2759 * archs can override this function if they must do something
2760 * after the modifying code is performed.
2761 */
ftrace_arch_code_modify_post_process(void)2762 void __weak ftrace_arch_code_modify_post_process(void)
2763 {
2764 }
2765
ftrace_modify_all_code(int command)2766 void ftrace_modify_all_code(int command)
2767 {
2768 int update = command & FTRACE_UPDATE_TRACE_FUNC;
2769 int mod_flags = 0;
2770 int err = 0;
2771
2772 if (command & FTRACE_MAY_SLEEP)
2773 mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2774
2775 /*
2776 * If the ftrace_caller calls a ftrace_ops func directly,
2777 * we need to make sure that it only traces functions it
2778 * expects to trace. When doing the switch of functions,
2779 * we need to update to the ftrace_ops_list_func first
2780 * before the transition between old and new calls are set,
2781 * as the ftrace_ops_list_func will check the ops hashes
2782 * to make sure the ops are having the right functions
2783 * traced.
2784 */
2785 if (update) {
2786 err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2787 if (FTRACE_WARN_ON(err))
2788 return;
2789 }
2790
2791 if (command & FTRACE_UPDATE_CALLS)
2792 ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2793 else if (command & FTRACE_DISABLE_CALLS)
2794 ftrace_replace_code(mod_flags);
2795
2796 if (update && ftrace_trace_function != ftrace_ops_list_func) {
2797 function_trace_op = set_function_trace_op;
2798 smp_wmb();
2799 /* If irqs are disabled, we are in stop machine */
2800 if (!irqs_disabled())
2801 smp_call_function(ftrace_sync_ipi, NULL, 1);
2802 err = ftrace_update_ftrace_func(ftrace_trace_function);
2803 if (FTRACE_WARN_ON(err))
2804 return;
2805 }
2806
2807 if (command & FTRACE_START_FUNC_RET)
2808 err = ftrace_enable_ftrace_graph_caller();
2809 else if (command & FTRACE_STOP_FUNC_RET)
2810 err = ftrace_disable_ftrace_graph_caller();
2811 FTRACE_WARN_ON(err);
2812 }
2813
__ftrace_modify_code(void * data)2814 static int __ftrace_modify_code(void *data)
2815 {
2816 int *command = data;
2817
2818 ftrace_modify_all_code(*command);
2819
2820 return 0;
2821 }
2822
2823 /**
2824 * ftrace_run_stop_machine - go back to the stop machine method
2825 * @command: The command to tell ftrace what to do
2826 *
2827 * If an arch needs to fall back to the stop machine method, the
2828 * it can call this function.
2829 */
ftrace_run_stop_machine(int command)2830 void ftrace_run_stop_machine(int command)
2831 {
2832 stop_machine(__ftrace_modify_code, &command, NULL);
2833 }
2834
2835 /**
2836 * arch_ftrace_update_code - modify the code to trace or not trace
2837 * @command: The command that needs to be done
2838 *
2839 * Archs can override this function if it does not need to
2840 * run stop_machine() to modify code.
2841 */
arch_ftrace_update_code(int command)2842 void __weak arch_ftrace_update_code(int command)
2843 {
2844 ftrace_run_stop_machine(command);
2845 }
2846
ftrace_run_update_code(int command)2847 static void ftrace_run_update_code(int command)
2848 {
2849 ftrace_arch_code_modify_prepare();
2850
2851 /*
2852 * By default we use stop_machine() to modify the code.
2853 * But archs can do what ever they want as long as it
2854 * is safe. The stop_machine() is the safest, but also
2855 * produces the most overhead.
2856 */
2857 arch_ftrace_update_code(command);
2858
2859 ftrace_arch_code_modify_post_process();
2860 }
2861
ftrace_run_modify_code(struct ftrace_ops * ops,int command,struct ftrace_ops_hash * old_hash)2862 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2863 struct ftrace_ops_hash *old_hash)
2864 {
2865 ops->flags |= FTRACE_OPS_FL_MODIFYING;
2866 ops->old_hash.filter_hash = old_hash->filter_hash;
2867 ops->old_hash.notrace_hash = old_hash->notrace_hash;
2868 ftrace_run_update_code(command);
2869 ops->old_hash.filter_hash = NULL;
2870 ops->old_hash.notrace_hash = NULL;
2871 ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2872 }
2873
2874 static ftrace_func_t saved_ftrace_func;
2875 static int ftrace_start_up;
2876
arch_ftrace_trampoline_free(struct ftrace_ops * ops)2877 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2878 {
2879 }
2880
2881 /* List of trace_ops that have allocated trampolines */
2882 static LIST_HEAD(ftrace_ops_trampoline_list);
2883
ftrace_add_trampoline_to_kallsyms(struct ftrace_ops * ops)2884 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2885 {
2886 lockdep_assert_held(&ftrace_lock);
2887 list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2888 }
2889
ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops * ops)2890 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2891 {
2892 lockdep_assert_held(&ftrace_lock);
2893 list_del_rcu(&ops->list);
2894 synchronize_rcu();
2895 }
2896
2897 /*
2898 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2899 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2900 * not a module.
2901 */
2902 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2903 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2904
ftrace_trampoline_free(struct ftrace_ops * ops)2905 static void ftrace_trampoline_free(struct ftrace_ops *ops)
2906 {
2907 if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2908 ops->trampoline) {
2909 /*
2910 * Record the text poke event before the ksymbol unregister
2911 * event.
2912 */
2913 perf_event_text_poke((void *)ops->trampoline,
2914 (void *)ops->trampoline,
2915 ops->trampoline_size, NULL, 0);
2916 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2917 ops->trampoline, ops->trampoline_size,
2918 true, FTRACE_TRAMPOLINE_SYM);
2919 /* Remove from kallsyms after the perf events */
2920 ftrace_remove_trampoline_from_kallsyms(ops);
2921 }
2922
2923 arch_ftrace_trampoline_free(ops);
2924 }
2925
ftrace_startup_enable(int command)2926 static void ftrace_startup_enable(int command)
2927 {
2928 if (saved_ftrace_func != ftrace_trace_function) {
2929 saved_ftrace_func = ftrace_trace_function;
2930 command |= FTRACE_UPDATE_TRACE_FUNC;
2931 }
2932
2933 if (!command || !ftrace_enabled)
2934 return;
2935
2936 ftrace_run_update_code(command);
2937 }
2938
ftrace_startup_all(int command)2939 static void ftrace_startup_all(int command)
2940 {
2941 update_all_ops = true;
2942 ftrace_startup_enable(command);
2943 update_all_ops = false;
2944 }
2945
ftrace_startup(struct ftrace_ops * ops,int command)2946 int ftrace_startup(struct ftrace_ops *ops, int command)
2947 {
2948 int ret;
2949
2950 if (unlikely(ftrace_disabled))
2951 return -ENODEV;
2952
2953 ret = __register_ftrace_function(ops);
2954 if (ret)
2955 return ret;
2956
2957 ftrace_start_up++;
2958
2959 /*
2960 * Note that ftrace probes uses this to start up
2961 * and modify functions it will probe. But we still
2962 * set the ADDING flag for modification, as probes
2963 * do not have trampolines. If they add them in the
2964 * future, then the probes will need to distinguish
2965 * between adding and updating probes.
2966 */
2967 ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2968
2969 ret = ftrace_hash_ipmodify_enable(ops);
2970 if (ret < 0) {
2971 /* Rollback registration process */
2972 __unregister_ftrace_function(ops);
2973 ftrace_start_up--;
2974 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2975 if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2976 ftrace_trampoline_free(ops);
2977 return ret;
2978 }
2979
2980 if (ftrace_hash_rec_enable(ops, 1))
2981 command |= FTRACE_UPDATE_CALLS;
2982
2983 ftrace_startup_enable(command);
2984
2985 /*
2986 * If ftrace is in an undefined state, we just remove ops from list
2987 * to prevent the NULL pointer, instead of totally rolling it back and
2988 * free trampoline, because those actions could cause further damage.
2989 */
2990 if (unlikely(ftrace_disabled)) {
2991 __unregister_ftrace_function(ops);
2992 return -ENODEV;
2993 }
2994
2995 ops->flags &= ~FTRACE_OPS_FL_ADDING;
2996
2997 return 0;
2998 }
2999
ftrace_shutdown(struct ftrace_ops * ops,int command)3000 int ftrace_shutdown(struct ftrace_ops *ops, int command)
3001 {
3002 int ret;
3003
3004 if (unlikely(ftrace_disabled))
3005 return -ENODEV;
3006
3007 ret = __unregister_ftrace_function(ops);
3008 if (ret)
3009 return ret;
3010
3011 ftrace_start_up--;
3012 /*
3013 * Just warn in case of unbalance, no need to kill ftrace, it's not
3014 * critical but the ftrace_call callers may be never nopped again after
3015 * further ftrace uses.
3016 */
3017 WARN_ON_ONCE(ftrace_start_up < 0);
3018
3019 /* Disabling ipmodify never fails */
3020 ftrace_hash_ipmodify_disable(ops);
3021
3022 if (ftrace_hash_rec_disable(ops, 1))
3023 command |= FTRACE_UPDATE_CALLS;
3024
3025 ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3026
3027 if (saved_ftrace_func != ftrace_trace_function) {
3028 saved_ftrace_func = ftrace_trace_function;
3029 command |= FTRACE_UPDATE_TRACE_FUNC;
3030 }
3031
3032 if (!command || !ftrace_enabled)
3033 goto out;
3034
3035 /*
3036 * If the ops uses a trampoline, then it needs to be
3037 * tested first on update.
3038 */
3039 ops->flags |= FTRACE_OPS_FL_REMOVING;
3040 removed_ops = ops;
3041
3042 /* The trampoline logic checks the old hashes */
3043 ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3044 ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3045
3046 ftrace_run_update_code(command);
3047
3048 /*
3049 * If there's no more ops registered with ftrace, run a
3050 * sanity check to make sure all rec flags are cleared.
3051 */
3052 if (rcu_dereference_protected(ftrace_ops_list,
3053 lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3054 struct ftrace_page *pg;
3055 struct dyn_ftrace *rec;
3056
3057 do_for_each_ftrace_rec(pg, rec) {
3058 if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
3059 pr_warn(" %pS flags:%lx\n",
3060 (void *)rec->ip, rec->flags);
3061 } while_for_each_ftrace_rec();
3062 }
3063
3064 ops->old_hash.filter_hash = NULL;
3065 ops->old_hash.notrace_hash = NULL;
3066
3067 removed_ops = NULL;
3068 ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3069
3070 out:
3071 /*
3072 * Dynamic ops may be freed, we must make sure that all
3073 * callers are done before leaving this function.
3074 * The same goes for freeing the per_cpu data of the per_cpu
3075 * ops.
3076 */
3077 if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3078 /*
3079 * We need to do a hard force of sched synchronization.
3080 * This is because we use preempt_disable() to do RCU, but
3081 * the function tracers can be called where RCU is not watching
3082 * (like before user_exit()). We can not rely on the RCU
3083 * infrastructure to do the synchronization, thus we must do it
3084 * ourselves.
3085 */
3086 synchronize_rcu_tasks_rude();
3087
3088 /*
3089 * When the kernel is preemptive, tasks can be preempted
3090 * while on a ftrace trampoline. Just scheduling a task on
3091 * a CPU is not good enough to flush them. Calling
3092 * synchronize_rcu_tasks() will wait for those tasks to
3093 * execute and either schedule voluntarily or enter user space.
3094 */
3095 if (IS_ENABLED(CONFIG_PREEMPTION))
3096 synchronize_rcu_tasks();
3097
3098 ftrace_trampoline_free(ops);
3099 }
3100
3101 return 0;
3102 }
3103
3104 static u64 ftrace_update_time;
3105 unsigned long ftrace_update_tot_cnt;
3106 unsigned long ftrace_number_of_pages;
3107 unsigned long ftrace_number_of_groups;
3108
ops_traces_mod(struct ftrace_ops * ops)3109 static inline int ops_traces_mod(struct ftrace_ops *ops)
3110 {
3111 /*
3112 * Filter_hash being empty will default to trace module.
3113 * But notrace hash requires a test of individual module functions.
3114 */
3115 return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3116 ftrace_hash_empty(ops->func_hash->notrace_hash);
3117 }
3118
ftrace_update_code(struct module * mod,struct ftrace_page * new_pgs)3119 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3120 {
3121 bool init_nop = ftrace_need_init_nop();
3122 struct ftrace_page *pg;
3123 struct dyn_ftrace *p;
3124 u64 start, stop;
3125 unsigned long update_cnt = 0;
3126 unsigned long rec_flags = 0;
3127 int i;
3128
3129 start = ftrace_now(raw_smp_processor_id());
3130
3131 /*
3132 * When a module is loaded, this function is called to convert
3133 * the calls to mcount in its text to nops, and also to create
3134 * an entry in the ftrace data. Now, if ftrace is activated
3135 * after this call, but before the module sets its text to
3136 * read-only, the modification of enabling ftrace can fail if
3137 * the read-only is done while ftrace is converting the calls.
3138 * To prevent this, the module's records are set as disabled
3139 * and will be enabled after the call to set the module's text
3140 * to read-only.
3141 */
3142 if (mod)
3143 rec_flags |= FTRACE_FL_DISABLED;
3144
3145 for (pg = new_pgs; pg; pg = pg->next) {
3146
3147 for (i = 0; i < pg->index; i++) {
3148
3149 /* If something went wrong, bail without enabling anything */
3150 if (unlikely(ftrace_disabled))
3151 return -1;
3152
3153 p = &pg->records[i];
3154 p->flags = rec_flags;
3155
3156 /*
3157 * Do the initial record conversion from mcount jump
3158 * to the NOP instructions.
3159 */
3160 if (init_nop && !ftrace_nop_initialize(mod, p))
3161 break;
3162
3163 update_cnt++;
3164 }
3165 }
3166
3167 stop = ftrace_now(raw_smp_processor_id());
3168 ftrace_update_time = stop - start;
3169 ftrace_update_tot_cnt += update_cnt;
3170
3171 return 0;
3172 }
3173
ftrace_allocate_records(struct ftrace_page * pg,int count)3174 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3175 {
3176 int order;
3177 int pages;
3178 int cnt;
3179
3180 if (WARN_ON(!count))
3181 return -EINVAL;
3182
3183 /* We want to fill as much as possible, with no empty pages */
3184 pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3185 order = fls(pages) - 1;
3186
3187 again:
3188 pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3189
3190 if (!pg->records) {
3191 /* if we can't allocate this size, try something smaller */
3192 if (!order)
3193 return -ENOMEM;
3194 order--;
3195 goto again;
3196 }
3197
3198 ftrace_number_of_pages += 1 << order;
3199 ftrace_number_of_groups++;
3200
3201 cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3202 pg->order = order;
3203
3204 if (cnt > count)
3205 cnt = count;
3206
3207 return cnt;
3208 }
3209
3210 static struct ftrace_page *
ftrace_allocate_pages(unsigned long num_to_init)3211 ftrace_allocate_pages(unsigned long num_to_init)
3212 {
3213 struct ftrace_page *start_pg;
3214 struct ftrace_page *pg;
3215 int cnt;
3216
3217 if (!num_to_init)
3218 return NULL;
3219
3220 start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3221 if (!pg)
3222 return NULL;
3223
3224 /*
3225 * Try to allocate as much as possible in one continues
3226 * location that fills in all of the space. We want to
3227 * waste as little space as possible.
3228 */
3229 for (;;) {
3230 cnt = ftrace_allocate_records(pg, num_to_init);
3231 if (cnt < 0)
3232 goto free_pages;
3233
3234 num_to_init -= cnt;
3235 if (!num_to_init)
3236 break;
3237
3238 pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3239 if (!pg->next)
3240 goto free_pages;
3241
3242 pg = pg->next;
3243 }
3244
3245 return start_pg;
3246
3247 free_pages:
3248 pg = start_pg;
3249 while (pg) {
3250 if (pg->records) {
3251 free_pages((unsigned long)pg->records, pg->order);
3252 ftrace_number_of_pages -= 1 << pg->order;
3253 }
3254 start_pg = pg->next;
3255 kfree(pg);
3256 pg = start_pg;
3257 ftrace_number_of_groups--;
3258 }
3259 pr_info("ftrace: FAILED to allocate memory for functions\n");
3260 return NULL;
3261 }
3262
3263 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3264
3265 struct ftrace_iterator {
3266 loff_t pos;
3267 loff_t func_pos;
3268 loff_t mod_pos;
3269 struct ftrace_page *pg;
3270 struct dyn_ftrace *func;
3271 struct ftrace_func_probe *probe;
3272 struct ftrace_func_entry *probe_entry;
3273 struct trace_parser parser;
3274 struct ftrace_hash *hash;
3275 struct ftrace_ops *ops;
3276 struct trace_array *tr;
3277 struct list_head *mod_list;
3278 int pidx;
3279 int idx;
3280 unsigned flags;
3281 };
3282
3283 static void *
t_probe_next(struct seq_file * m,loff_t * pos)3284 t_probe_next(struct seq_file *m, loff_t *pos)
3285 {
3286 struct ftrace_iterator *iter = m->private;
3287 struct trace_array *tr = iter->ops->private;
3288 struct list_head *func_probes;
3289 struct ftrace_hash *hash;
3290 struct list_head *next;
3291 struct hlist_node *hnd = NULL;
3292 struct hlist_head *hhd;
3293 int size;
3294
3295 (*pos)++;
3296 iter->pos = *pos;
3297
3298 if (!tr)
3299 return NULL;
3300
3301 func_probes = &tr->func_probes;
3302 if (list_empty(func_probes))
3303 return NULL;
3304
3305 if (!iter->probe) {
3306 next = func_probes->next;
3307 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3308 }
3309
3310 if (iter->probe_entry)
3311 hnd = &iter->probe_entry->hlist;
3312
3313 hash = iter->probe->ops.func_hash->filter_hash;
3314
3315 /*
3316 * A probe being registered may temporarily have an empty hash
3317 * and it's at the end of the func_probes list.
3318 */
3319 if (!hash || hash == EMPTY_HASH)
3320 return NULL;
3321
3322 size = 1 << hash->size_bits;
3323
3324 retry:
3325 if (iter->pidx >= size) {
3326 if (iter->probe->list.next == func_probes)
3327 return NULL;
3328 next = iter->probe->list.next;
3329 iter->probe = list_entry(next, struct ftrace_func_probe, list);
3330 hash = iter->probe->ops.func_hash->filter_hash;
3331 size = 1 << hash->size_bits;
3332 iter->pidx = 0;
3333 }
3334
3335 hhd = &hash->buckets[iter->pidx];
3336
3337 if (hlist_empty(hhd)) {
3338 iter->pidx++;
3339 hnd = NULL;
3340 goto retry;
3341 }
3342
3343 if (!hnd)
3344 hnd = hhd->first;
3345 else {
3346 hnd = hnd->next;
3347 if (!hnd) {
3348 iter->pidx++;
3349 goto retry;
3350 }
3351 }
3352
3353 if (WARN_ON_ONCE(!hnd))
3354 return NULL;
3355
3356 iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3357
3358 return iter;
3359 }
3360
t_probe_start(struct seq_file * m,loff_t * pos)3361 static void *t_probe_start(struct seq_file *m, loff_t *pos)
3362 {
3363 struct ftrace_iterator *iter = m->private;
3364 void *p = NULL;
3365 loff_t l;
3366
3367 if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3368 return NULL;
3369
3370 if (iter->mod_pos > *pos)
3371 return NULL;
3372
3373 iter->probe = NULL;
3374 iter->probe_entry = NULL;
3375 iter->pidx = 0;
3376 for (l = 0; l <= (*pos - iter->mod_pos); ) {
3377 p = t_probe_next(m, &l);
3378 if (!p)
3379 break;
3380 }
3381 if (!p)
3382 return NULL;
3383
3384 /* Only set this if we have an item */
3385 iter->flags |= FTRACE_ITER_PROBE;
3386
3387 return iter;
3388 }
3389
3390 static int
t_probe_show(struct seq_file * m,struct ftrace_iterator * iter)3391 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3392 {
3393 struct ftrace_func_entry *probe_entry;
3394 struct ftrace_probe_ops *probe_ops;
3395 struct ftrace_func_probe *probe;
3396
3397 probe = iter->probe;
3398 probe_entry = iter->probe_entry;
3399
3400 if (WARN_ON_ONCE(!probe || !probe_entry))
3401 return -EIO;
3402
3403 probe_ops = probe->probe_ops;
3404
3405 if (probe_ops->print)
3406 return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3407
3408 seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3409 (void *)probe_ops->func);
3410
3411 return 0;
3412 }
3413
3414 static void *
t_mod_next(struct seq_file * m,loff_t * pos)3415 t_mod_next(struct seq_file *m, loff_t *pos)
3416 {
3417 struct ftrace_iterator *iter = m->private;
3418 struct trace_array *tr = iter->tr;
3419
3420 (*pos)++;
3421 iter->pos = *pos;
3422
3423 iter->mod_list = iter->mod_list->next;
3424
3425 if (iter->mod_list == &tr->mod_trace ||
3426 iter->mod_list == &tr->mod_notrace) {
3427 iter->flags &= ~FTRACE_ITER_MOD;
3428 return NULL;
3429 }
3430
3431 iter->mod_pos = *pos;
3432
3433 return iter;
3434 }
3435
t_mod_start(struct seq_file * m,loff_t * pos)3436 static void *t_mod_start(struct seq_file *m, loff_t *pos)
3437 {
3438 struct ftrace_iterator *iter = m->private;
3439 void *p = NULL;
3440 loff_t l;
3441
3442 if (iter->func_pos > *pos)
3443 return NULL;
3444
3445 iter->mod_pos = iter->func_pos;
3446
3447 /* probes are only available if tr is set */
3448 if (!iter->tr)
3449 return NULL;
3450
3451 for (l = 0; l <= (*pos - iter->func_pos); ) {
3452 p = t_mod_next(m, &l);
3453 if (!p)
3454 break;
3455 }
3456 if (!p) {
3457 iter->flags &= ~FTRACE_ITER_MOD;
3458 return t_probe_start(m, pos);
3459 }
3460
3461 /* Only set this if we have an item */
3462 iter->flags |= FTRACE_ITER_MOD;
3463
3464 return iter;
3465 }
3466
3467 static int
t_mod_show(struct seq_file * m,struct ftrace_iterator * iter)3468 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3469 {
3470 struct ftrace_mod_load *ftrace_mod;
3471 struct trace_array *tr = iter->tr;
3472
3473 if (WARN_ON_ONCE(!iter->mod_list) ||
3474 iter->mod_list == &tr->mod_trace ||
3475 iter->mod_list == &tr->mod_notrace)
3476 return -EIO;
3477
3478 ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3479
3480 if (ftrace_mod->func)
3481 seq_printf(m, "%s", ftrace_mod->func);
3482 else
3483 seq_putc(m, '*');
3484
3485 seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3486
3487 return 0;
3488 }
3489
3490 static void *
t_func_next(struct seq_file * m,loff_t * pos)3491 t_func_next(struct seq_file *m, loff_t *pos)
3492 {
3493 struct ftrace_iterator *iter = m->private;
3494 struct dyn_ftrace *rec = NULL;
3495
3496 (*pos)++;
3497
3498 retry:
3499 if (iter->idx >= iter->pg->index) {
3500 if (iter->pg->next) {
3501 iter->pg = iter->pg->next;
3502 iter->idx = 0;
3503 goto retry;
3504 }
3505 } else {
3506 rec = &iter->pg->records[iter->idx++];
3507 if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3508 !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3509
3510 ((iter->flags & FTRACE_ITER_ENABLED) &&
3511 !(rec->flags & FTRACE_FL_ENABLED))) {
3512
3513 rec = NULL;
3514 goto retry;
3515 }
3516 }
3517
3518 if (!rec)
3519 return NULL;
3520
3521 iter->pos = iter->func_pos = *pos;
3522 iter->func = rec;
3523
3524 return iter;
3525 }
3526
3527 static void *
t_next(struct seq_file * m,void * v,loff_t * pos)3528 t_next(struct seq_file *m, void *v, loff_t *pos)
3529 {
3530 struct ftrace_iterator *iter = m->private;
3531 loff_t l = *pos; /* t_probe_start() must use original pos */
3532 void *ret;
3533
3534 if (unlikely(ftrace_disabled))
3535 return NULL;
3536
3537 if (iter->flags & FTRACE_ITER_PROBE)
3538 return t_probe_next(m, pos);
3539
3540 if (iter->flags & FTRACE_ITER_MOD)
3541 return t_mod_next(m, pos);
3542
3543 if (iter->flags & FTRACE_ITER_PRINTALL) {
3544 /* next must increment pos, and t_probe_start does not */
3545 (*pos)++;
3546 return t_mod_start(m, &l);
3547 }
3548
3549 ret = t_func_next(m, pos);
3550
3551 if (!ret)
3552 return t_mod_start(m, &l);
3553
3554 return ret;
3555 }
3556
reset_iter_read(struct ftrace_iterator * iter)3557 static void reset_iter_read(struct ftrace_iterator *iter)
3558 {
3559 iter->pos = 0;
3560 iter->func_pos = 0;
3561 iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3562 }
3563
t_start(struct seq_file * m,loff_t * pos)3564 static void *t_start(struct seq_file *m, loff_t *pos)
3565 {
3566 struct ftrace_iterator *iter = m->private;
3567 void *p = NULL;
3568 loff_t l;
3569
3570 mutex_lock(&ftrace_lock);
3571
3572 if (unlikely(ftrace_disabled))
3573 return NULL;
3574
3575 /*
3576 * If an lseek was done, then reset and start from beginning.
3577 */
3578 if (*pos < iter->pos)
3579 reset_iter_read(iter);
3580
3581 /*
3582 * For set_ftrace_filter reading, if we have the filter
3583 * off, we can short cut and just print out that all
3584 * functions are enabled.
3585 */
3586 if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3587 ftrace_hash_empty(iter->hash)) {
3588 iter->func_pos = 1; /* Account for the message */
3589 if (*pos > 0)
3590 return t_mod_start(m, pos);
3591 iter->flags |= FTRACE_ITER_PRINTALL;
3592 /* reset in case of seek/pread */
3593 iter->flags &= ~FTRACE_ITER_PROBE;
3594 return iter;
3595 }
3596
3597 if (iter->flags & FTRACE_ITER_MOD)
3598 return t_mod_start(m, pos);
3599
3600 /*
3601 * Unfortunately, we need to restart at ftrace_pages_start
3602 * every time we let go of the ftrace_mutex. This is because
3603 * those pointers can change without the lock.
3604 */
3605 iter->pg = ftrace_pages_start;
3606 iter->idx = 0;
3607 for (l = 0; l <= *pos; ) {
3608 p = t_func_next(m, &l);
3609 if (!p)
3610 break;
3611 }
3612
3613 if (!p)
3614 return t_mod_start(m, pos);
3615
3616 return iter;
3617 }
3618
t_stop(struct seq_file * m,void * p)3619 static void t_stop(struct seq_file *m, void *p)
3620 {
3621 mutex_unlock(&ftrace_lock);
3622 }
3623
3624 void * __weak
arch_ftrace_trampoline_func(struct ftrace_ops * ops,struct dyn_ftrace * rec)3625 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3626 {
3627 return NULL;
3628 }
3629
add_trampoline_func(struct seq_file * m,struct ftrace_ops * ops,struct dyn_ftrace * rec)3630 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3631 struct dyn_ftrace *rec)
3632 {
3633 void *ptr;
3634
3635 ptr = arch_ftrace_trampoline_func(ops, rec);
3636 if (ptr)
3637 seq_printf(m, " ->%pS", ptr);
3638 }
3639
3640 #ifdef FTRACE_MCOUNT_MAX_OFFSET
3641 /*
3642 * Weak functions can still have an mcount/fentry that is saved in
3643 * the __mcount_loc section. These can be detected by having a
3644 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3645 * symbol found by kallsyms is not the function that the mcount/fentry
3646 * is part of. The offset is much greater in these cases.
3647 *
3648 * Test the record to make sure that the ip points to a valid kallsyms
3649 * and if not, mark it disabled.
3650 */
test_for_valid_rec(struct dyn_ftrace * rec)3651 static int test_for_valid_rec(struct dyn_ftrace *rec)
3652 {
3653 char str[KSYM_SYMBOL_LEN];
3654 unsigned long offset;
3655 const char *ret;
3656
3657 ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3658
3659 /* Weak functions can cause invalid addresses */
3660 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3661 rec->flags |= FTRACE_FL_DISABLED;
3662 return 0;
3663 }
3664 return 1;
3665 }
3666
3667 static struct workqueue_struct *ftrace_check_wq __initdata;
3668 static struct work_struct ftrace_check_work __initdata;
3669
3670 /*
3671 * Scan all the mcount/fentry entries to make sure they are valid.
3672 */
ftrace_check_work_func(struct work_struct * work)3673 static __init void ftrace_check_work_func(struct work_struct *work)
3674 {
3675 struct ftrace_page *pg;
3676 struct dyn_ftrace *rec;
3677
3678 mutex_lock(&ftrace_lock);
3679 do_for_each_ftrace_rec(pg, rec) {
3680 test_for_valid_rec(rec);
3681 } while_for_each_ftrace_rec();
3682 mutex_unlock(&ftrace_lock);
3683 }
3684
ftrace_check_for_weak_functions(void)3685 static int __init ftrace_check_for_weak_functions(void)
3686 {
3687 INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3688
3689 ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3690
3691 queue_work(ftrace_check_wq, &ftrace_check_work);
3692 return 0;
3693 }
3694
ftrace_check_sync(void)3695 static int __init ftrace_check_sync(void)
3696 {
3697 /* Make sure the ftrace_check updates are finished */
3698 if (ftrace_check_wq)
3699 destroy_workqueue(ftrace_check_wq);
3700 return 0;
3701 }
3702
3703 late_initcall_sync(ftrace_check_sync);
3704 subsys_initcall(ftrace_check_for_weak_functions);
3705
print_rec(struct seq_file * m,unsigned long ip)3706 static int print_rec(struct seq_file *m, unsigned long ip)
3707 {
3708 unsigned long offset;
3709 char str[KSYM_SYMBOL_LEN];
3710 char *modname;
3711 const char *ret;
3712
3713 ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3714 /* Weak functions can cause invalid addresses */
3715 if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3716 snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3717 FTRACE_INVALID_FUNCTION, offset);
3718 ret = NULL;
3719 }
3720
3721 seq_puts(m, str);
3722 if (modname)
3723 seq_printf(m, " [%s]", modname);
3724 return ret == NULL ? -1 : 0;
3725 }
3726 #else
test_for_valid_rec(struct dyn_ftrace * rec)3727 static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3728 {
3729 return 1;
3730 }
3731
print_rec(struct seq_file * m,unsigned long ip)3732 static inline int print_rec(struct seq_file *m, unsigned long ip)
3733 {
3734 seq_printf(m, "%ps", (void *)ip);
3735 return 0;
3736 }
3737 #endif
3738
t_show(struct seq_file * m,void * v)3739 static int t_show(struct seq_file *m, void *v)
3740 {
3741 struct ftrace_iterator *iter = m->private;
3742 struct dyn_ftrace *rec;
3743
3744 if (iter->flags & FTRACE_ITER_PROBE)
3745 return t_probe_show(m, iter);
3746
3747 if (iter->flags & FTRACE_ITER_MOD)
3748 return t_mod_show(m, iter);
3749
3750 if (iter->flags & FTRACE_ITER_PRINTALL) {
3751 if (iter->flags & FTRACE_ITER_NOTRACE)
3752 seq_puts(m, "#### no functions disabled ####\n");
3753 else
3754 seq_puts(m, "#### all functions enabled ####\n");
3755 return 0;
3756 }
3757
3758 rec = iter->func;
3759
3760 if (!rec)
3761 return 0;
3762
3763 if (print_rec(m, rec->ip)) {
3764 /* This should only happen when a rec is disabled */
3765 WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3766 seq_putc(m, '\n');
3767 return 0;
3768 }
3769
3770 if (iter->flags & FTRACE_ITER_ENABLED) {
3771 struct ftrace_ops *ops;
3772
3773 seq_printf(m, " (%ld)%s%s%s",
3774 ftrace_rec_count(rec),
3775 rec->flags & FTRACE_FL_REGS ? " R" : " ",
3776 rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
3777 rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
3778 if (rec->flags & FTRACE_FL_TRAMP_EN) {
3779 ops = ftrace_find_tramp_ops_any(rec);
3780 if (ops) {
3781 do {
3782 seq_printf(m, "\ttramp: %pS (%pS)",
3783 (void *)ops->trampoline,
3784 (void *)ops->func);
3785 add_trampoline_func(m, ops, rec);
3786 ops = ftrace_find_tramp_ops_next(rec, ops);
3787 } while (ops);
3788 } else
3789 seq_puts(m, "\ttramp: ERROR!");
3790 } else {
3791 add_trampoline_func(m, NULL, rec);
3792 }
3793 if (rec->flags & FTRACE_FL_DIRECT) {
3794 unsigned long direct;
3795
3796 direct = ftrace_find_rec_direct(rec->ip);
3797 if (direct)
3798 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3799 }
3800 }
3801
3802 seq_putc(m, '\n');
3803
3804 return 0;
3805 }
3806
3807 static const struct seq_operations show_ftrace_seq_ops = {
3808 .start = t_start,
3809 .next = t_next,
3810 .stop = t_stop,
3811 .show = t_show,
3812 };
3813
3814 static int
ftrace_avail_open(struct inode * inode,struct file * file)3815 ftrace_avail_open(struct inode *inode, struct file *file)
3816 {
3817 struct ftrace_iterator *iter;
3818 int ret;
3819
3820 ret = security_locked_down(LOCKDOWN_TRACEFS);
3821 if (ret)
3822 return ret;
3823
3824 if (unlikely(ftrace_disabled))
3825 return -ENODEV;
3826
3827 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3828 if (!iter)
3829 return -ENOMEM;
3830
3831 iter->pg = ftrace_pages_start;
3832 iter->ops = &global_ops;
3833
3834 return 0;
3835 }
3836
3837 static int
ftrace_enabled_open(struct inode * inode,struct file * file)3838 ftrace_enabled_open(struct inode *inode, struct file *file)
3839 {
3840 struct ftrace_iterator *iter;
3841
3842 /*
3843 * This shows us what functions are currently being
3844 * traced and by what. Not sure if we want lockdown
3845 * to hide such critical information for an admin.
3846 * Although, perhaps it can show information we don't
3847 * want people to see, but if something is tracing
3848 * something, we probably want to know about it.
3849 */
3850
3851 iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3852 if (!iter)
3853 return -ENOMEM;
3854
3855 iter->pg = ftrace_pages_start;
3856 iter->flags = FTRACE_ITER_ENABLED;
3857 iter->ops = &global_ops;
3858
3859 return 0;
3860 }
3861
3862 /**
3863 * ftrace_regex_open - initialize function tracer filter files
3864 * @ops: The ftrace_ops that hold the hash filters
3865 * @flag: The type of filter to process
3866 * @inode: The inode, usually passed in to your open routine
3867 * @file: The file, usually passed in to your open routine
3868 *
3869 * ftrace_regex_open() initializes the filter files for the
3870 * @ops. Depending on @flag it may process the filter hash or
3871 * the notrace hash of @ops. With this called from the open
3872 * routine, you can use ftrace_filter_write() for the write
3873 * routine if @flag has FTRACE_ITER_FILTER set, or
3874 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3875 * tracing_lseek() should be used as the lseek routine, and
3876 * release must call ftrace_regex_release().
3877 */
3878 int
ftrace_regex_open(struct ftrace_ops * ops,int flag,struct inode * inode,struct file * file)3879 ftrace_regex_open(struct ftrace_ops *ops, int flag,
3880 struct inode *inode, struct file *file)
3881 {
3882 struct ftrace_iterator *iter;
3883 struct ftrace_hash *hash;
3884 struct list_head *mod_head;
3885 struct trace_array *tr = ops->private;
3886 int ret = -ENOMEM;
3887
3888 ftrace_ops_init(ops);
3889
3890 if (unlikely(ftrace_disabled))
3891 return -ENODEV;
3892
3893 if (tracing_check_open_get_tr(tr))
3894 return -ENODEV;
3895
3896 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3897 if (!iter)
3898 goto out;
3899
3900 if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3901 goto out;
3902
3903 iter->ops = ops;
3904 iter->flags = flag;
3905 iter->tr = tr;
3906
3907 mutex_lock(&ops->func_hash->regex_lock);
3908
3909 if (flag & FTRACE_ITER_NOTRACE) {
3910 hash = ops->func_hash->notrace_hash;
3911 mod_head = tr ? &tr->mod_notrace : NULL;
3912 } else {
3913 hash = ops->func_hash->filter_hash;
3914 mod_head = tr ? &tr->mod_trace : NULL;
3915 }
3916
3917 iter->mod_list = mod_head;
3918
3919 if (file->f_mode & FMODE_WRITE) {
3920 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3921
3922 if (file->f_flags & O_TRUNC) {
3923 iter->hash = alloc_ftrace_hash(size_bits);
3924 clear_ftrace_mod_list(mod_head);
3925 } else {
3926 iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3927 }
3928
3929 if (!iter->hash) {
3930 trace_parser_put(&iter->parser);
3931 goto out_unlock;
3932 }
3933 } else
3934 iter->hash = hash;
3935
3936 ret = 0;
3937
3938 if (file->f_mode & FMODE_READ) {
3939 iter->pg = ftrace_pages_start;
3940
3941 ret = seq_open(file, &show_ftrace_seq_ops);
3942 if (!ret) {
3943 struct seq_file *m = file->private_data;
3944 m->private = iter;
3945 } else {
3946 /* Failed */
3947 free_ftrace_hash(iter->hash);
3948 trace_parser_put(&iter->parser);
3949 }
3950 } else
3951 file->private_data = iter;
3952
3953 out_unlock:
3954 mutex_unlock(&ops->func_hash->regex_lock);
3955
3956 out:
3957 if (ret) {
3958 kfree(iter);
3959 if (tr)
3960 trace_array_put(tr);
3961 }
3962
3963 return ret;
3964 }
3965
3966 static int
ftrace_filter_open(struct inode * inode,struct file * file)3967 ftrace_filter_open(struct inode *inode, struct file *file)
3968 {
3969 struct ftrace_ops *ops = inode->i_private;
3970
3971 /* Checks for tracefs lockdown */
3972 return ftrace_regex_open(ops,
3973 FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3974 inode, file);
3975 }
3976
3977 static int
ftrace_notrace_open(struct inode * inode,struct file * file)3978 ftrace_notrace_open(struct inode *inode, struct file *file)
3979 {
3980 struct ftrace_ops *ops = inode->i_private;
3981
3982 /* Checks for tracefs lockdown */
3983 return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3984 inode, file);
3985 }
3986
3987 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3988 struct ftrace_glob {
3989 char *search;
3990 unsigned len;
3991 int type;
3992 };
3993
3994 /*
3995 * If symbols in an architecture don't correspond exactly to the user-visible
3996 * name of what they represent, it is possible to define this function to
3997 * perform the necessary adjustments.
3998 */
arch_ftrace_match_adjust(char * str,const char * search)3999 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4000 {
4001 return str;
4002 }
4003
ftrace_match(char * str,struct ftrace_glob * g)4004 static int ftrace_match(char *str, struct ftrace_glob *g)
4005 {
4006 int matched = 0;
4007 int slen;
4008
4009 str = arch_ftrace_match_adjust(str, g->search);
4010
4011 switch (g->type) {
4012 case MATCH_FULL:
4013 if (strcmp(str, g->search) == 0)
4014 matched = 1;
4015 break;
4016 case MATCH_FRONT_ONLY:
4017 if (strncmp(str, g->search, g->len) == 0)
4018 matched = 1;
4019 break;
4020 case MATCH_MIDDLE_ONLY:
4021 if (strstr(str, g->search))
4022 matched = 1;
4023 break;
4024 case MATCH_END_ONLY:
4025 slen = strlen(str);
4026 if (slen >= g->len &&
4027 memcmp(str + slen - g->len, g->search, g->len) == 0)
4028 matched = 1;
4029 break;
4030 case MATCH_GLOB:
4031 if (glob_match(g->search, str))
4032 matched = 1;
4033 break;
4034 }
4035
4036 return matched;
4037 }
4038
4039 static int
enter_record(struct ftrace_hash * hash,struct dyn_ftrace * rec,int clear_filter)4040 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4041 {
4042 struct ftrace_func_entry *entry;
4043 int ret = 0;
4044
4045 entry = ftrace_lookup_ip(hash, rec->ip);
4046 if (clear_filter) {
4047 /* Do nothing if it doesn't exist */
4048 if (!entry)
4049 return 0;
4050
4051 free_hash_entry(hash, entry);
4052 } else {
4053 /* Do nothing if it exists */
4054 if (entry)
4055 return 0;
4056
4057 ret = add_hash_entry(hash, rec->ip);
4058 }
4059 return ret;
4060 }
4061
4062 static int
add_rec_by_index(struct ftrace_hash * hash,struct ftrace_glob * func_g,int clear_filter)4063 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4064 int clear_filter)
4065 {
4066 long index = simple_strtoul(func_g->search, NULL, 0);
4067 struct ftrace_page *pg;
4068 struct dyn_ftrace *rec;
4069
4070 /* The index starts at 1 */
4071 if (--index < 0)
4072 return 0;
4073
4074 do_for_each_ftrace_rec(pg, rec) {
4075 if (pg->index <= index) {
4076 index -= pg->index;
4077 /* this is a double loop, break goes to the next page */
4078 break;
4079 }
4080 rec = &pg->records[index];
4081 enter_record(hash, rec, clear_filter);
4082 return 1;
4083 } while_for_each_ftrace_rec();
4084 return 0;
4085 }
4086
4087 #ifdef FTRACE_MCOUNT_MAX_OFFSET
lookup_ip(unsigned long ip,char ** modname,char * str)4088 static int lookup_ip(unsigned long ip, char **modname, char *str)
4089 {
4090 unsigned long offset;
4091
4092 kallsyms_lookup(ip, NULL, &offset, modname, str);
4093 if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4094 return -1;
4095 return 0;
4096 }
4097 #else
lookup_ip(unsigned long ip,char ** modname,char * str)4098 static int lookup_ip(unsigned long ip, char **modname, char *str)
4099 {
4100 kallsyms_lookup(ip, NULL, NULL, modname, str);
4101 return 0;
4102 }
4103 #endif
4104
4105 static int
ftrace_match_record(struct dyn_ftrace * rec,struct ftrace_glob * func_g,struct ftrace_glob * mod_g,int exclude_mod)4106 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4107 struct ftrace_glob *mod_g, int exclude_mod)
4108 {
4109 char str[KSYM_SYMBOL_LEN];
4110 char *modname;
4111
4112 if (lookup_ip(rec->ip, &modname, str)) {
4113 /* This should only happen when a rec is disabled */
4114 WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4115 !(rec->flags & FTRACE_FL_DISABLED));
4116 return 0;
4117 }
4118
4119 if (mod_g) {
4120 int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4121
4122 /* blank module name to match all modules */
4123 if (!mod_g->len) {
4124 /* blank module globbing: modname xor exclude_mod */
4125 if (!exclude_mod != !modname)
4126 goto func_match;
4127 return 0;
4128 }
4129
4130 /*
4131 * exclude_mod is set to trace everything but the given
4132 * module. If it is set and the module matches, then
4133 * return 0. If it is not set, and the module doesn't match
4134 * also return 0. Otherwise, check the function to see if
4135 * that matches.
4136 */
4137 if (!mod_matches == !exclude_mod)
4138 return 0;
4139 func_match:
4140 /* blank search means to match all funcs in the mod */
4141 if (!func_g->len)
4142 return 1;
4143 }
4144
4145 return ftrace_match(str, func_g);
4146 }
4147
4148 static int
match_records(struct ftrace_hash * hash,char * func,int len,char * mod)4149 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4150 {
4151 struct ftrace_page *pg;
4152 struct dyn_ftrace *rec;
4153 struct ftrace_glob func_g = { .type = MATCH_FULL };
4154 struct ftrace_glob mod_g = { .type = MATCH_FULL };
4155 struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4156 int exclude_mod = 0;
4157 int found = 0;
4158 int ret;
4159 int clear_filter = 0;
4160
4161 if (func) {
4162 func_g.type = filter_parse_regex(func, len, &func_g.search,
4163 &clear_filter);
4164 func_g.len = strlen(func_g.search);
4165 }
4166
4167 if (mod) {
4168 mod_g.type = filter_parse_regex(mod, strlen(mod),
4169 &mod_g.search, &exclude_mod);
4170 mod_g.len = strlen(mod_g.search);
4171 }
4172
4173 mutex_lock(&ftrace_lock);
4174
4175 if (unlikely(ftrace_disabled))
4176 goto out_unlock;
4177
4178 if (func_g.type == MATCH_INDEX) {
4179 found = add_rec_by_index(hash, &func_g, clear_filter);
4180 goto out_unlock;
4181 }
4182
4183 do_for_each_ftrace_rec(pg, rec) {
4184
4185 if (rec->flags & FTRACE_FL_DISABLED)
4186 continue;
4187
4188 if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4189 ret = enter_record(hash, rec, clear_filter);
4190 if (ret < 0) {
4191 found = ret;
4192 goto out_unlock;
4193 }
4194 found = 1;
4195 }
4196 } while_for_each_ftrace_rec();
4197 out_unlock:
4198 mutex_unlock(&ftrace_lock);
4199
4200 return found;
4201 }
4202
4203 static int
ftrace_match_records(struct ftrace_hash * hash,char * buff,int len)4204 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4205 {
4206 return match_records(hash, buff, len, NULL);
4207 }
4208
ftrace_ops_update_code(struct ftrace_ops * ops,struct ftrace_ops_hash * old_hash)4209 static void ftrace_ops_update_code(struct ftrace_ops *ops,
4210 struct ftrace_ops_hash *old_hash)
4211 {
4212 struct ftrace_ops *op;
4213
4214 if (!ftrace_enabled)
4215 return;
4216
4217 if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4218 ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4219 return;
4220 }
4221
4222 /*
4223 * If this is the shared global_ops filter, then we need to
4224 * check if there is another ops that shares it, is enabled.
4225 * If so, we still need to run the modify code.
4226 */
4227 if (ops->func_hash != &global_ops.local_hash)
4228 return;
4229
4230 do_for_each_ftrace_op(op, ftrace_ops_list) {
4231 if (op->func_hash == &global_ops.local_hash &&
4232 op->flags & FTRACE_OPS_FL_ENABLED) {
4233 ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4234 /* Only need to do this once */
4235 return;
4236 }
4237 } while_for_each_ftrace_op(op);
4238 }
4239
ftrace_hash_move_and_update_ops(struct ftrace_ops * ops,struct ftrace_hash ** orig_hash,struct ftrace_hash * hash,int enable)4240 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4241 struct ftrace_hash **orig_hash,
4242 struct ftrace_hash *hash,
4243 int enable)
4244 {
4245 struct ftrace_ops_hash old_hash_ops;
4246 struct ftrace_hash *old_hash;
4247 int ret;
4248
4249 old_hash = *orig_hash;
4250 old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4251 old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4252 ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4253 if (!ret) {
4254 ftrace_ops_update_code(ops, &old_hash_ops);
4255 free_ftrace_hash_rcu(old_hash);
4256 }
4257 return ret;
4258 }
4259
module_exists(const char * module)4260 static bool module_exists(const char *module)
4261 {
4262 /* All modules have the symbol __this_module */
4263 static const char this_mod[] = "__this_module";
4264 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4265 unsigned long val;
4266 int n;
4267
4268 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4269
4270 if (n > sizeof(modname) - 1)
4271 return false;
4272
4273 val = module_kallsyms_lookup_name(modname);
4274 return val != 0;
4275 }
4276
cache_mod(struct trace_array * tr,const char * func,char * module,int enable)4277 static int cache_mod(struct trace_array *tr,
4278 const char *func, char *module, int enable)
4279 {
4280 struct ftrace_mod_load *ftrace_mod, *n;
4281 struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4282 int ret;
4283
4284 mutex_lock(&ftrace_lock);
4285
4286 /* We do not cache inverse filters */
4287 if (func[0] == '!') {
4288 func++;
4289 ret = -EINVAL;
4290
4291 /* Look to remove this hash */
4292 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4293 if (strcmp(ftrace_mod->module, module) != 0)
4294 continue;
4295
4296 /* no func matches all */
4297 if (strcmp(func, "*") == 0 ||
4298 (ftrace_mod->func &&
4299 strcmp(ftrace_mod->func, func) == 0)) {
4300 ret = 0;
4301 free_ftrace_mod(ftrace_mod);
4302 continue;
4303 }
4304 }
4305 goto out;
4306 }
4307
4308 ret = -EINVAL;
4309 /* We only care about modules that have not been loaded yet */
4310 if (module_exists(module))
4311 goto out;
4312
4313 /* Save this string off, and execute it when the module is loaded */
4314 ret = ftrace_add_mod(tr, func, module, enable);
4315 out:
4316 mutex_unlock(&ftrace_lock);
4317
4318 return ret;
4319 }
4320
4321 static int
4322 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4323 int reset, int enable);
4324
4325 #ifdef CONFIG_MODULES
process_mod_list(struct list_head * head,struct ftrace_ops * ops,char * mod,bool enable)4326 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4327 char *mod, bool enable)
4328 {
4329 struct ftrace_mod_load *ftrace_mod, *n;
4330 struct ftrace_hash **orig_hash, *new_hash;
4331 LIST_HEAD(process_mods);
4332 char *func;
4333
4334 mutex_lock(&ops->func_hash->regex_lock);
4335
4336 if (enable)
4337 orig_hash = &ops->func_hash->filter_hash;
4338 else
4339 orig_hash = &ops->func_hash->notrace_hash;
4340
4341 new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4342 *orig_hash);
4343 if (!new_hash)
4344 goto out; /* warn? */
4345
4346 mutex_lock(&ftrace_lock);
4347
4348 list_for_each_entry_safe(ftrace_mod, n, head, list) {
4349
4350 if (strcmp(ftrace_mod->module, mod) != 0)
4351 continue;
4352
4353 if (ftrace_mod->func)
4354 func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4355 else
4356 func = kstrdup("*", GFP_KERNEL);
4357
4358 if (!func) /* warn? */
4359 continue;
4360
4361 list_move(&ftrace_mod->list, &process_mods);
4362
4363 /* Use the newly allocated func, as it may be "*" */
4364 kfree(ftrace_mod->func);
4365 ftrace_mod->func = func;
4366 }
4367
4368 mutex_unlock(&ftrace_lock);
4369
4370 list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4371
4372 func = ftrace_mod->func;
4373
4374 /* Grabs ftrace_lock, which is why we have this extra step */
4375 match_records(new_hash, func, strlen(func), mod);
4376 free_ftrace_mod(ftrace_mod);
4377 }
4378
4379 if (enable && list_empty(head))
4380 new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4381
4382 mutex_lock(&ftrace_lock);
4383
4384 ftrace_hash_move_and_update_ops(ops, orig_hash,
4385 new_hash, enable);
4386 mutex_unlock(&ftrace_lock);
4387
4388 out:
4389 mutex_unlock(&ops->func_hash->regex_lock);
4390
4391 free_ftrace_hash(new_hash);
4392 }
4393
process_cached_mods(const char * mod_name)4394 static void process_cached_mods(const char *mod_name)
4395 {
4396 struct trace_array *tr;
4397 char *mod;
4398
4399 mod = kstrdup(mod_name, GFP_KERNEL);
4400 if (!mod)
4401 return;
4402
4403 mutex_lock(&trace_types_lock);
4404 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4405 if (!list_empty(&tr->mod_trace))
4406 process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4407 if (!list_empty(&tr->mod_notrace))
4408 process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4409 }
4410 mutex_unlock(&trace_types_lock);
4411
4412 kfree(mod);
4413 }
4414 #endif
4415
4416 /*
4417 * We register the module command as a template to show others how
4418 * to register the a command as well.
4419 */
4420
4421 static int
ftrace_mod_callback(struct trace_array * tr,struct ftrace_hash * hash,char * func_orig,char * cmd,char * module,int enable)4422 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4423 char *func_orig, char *cmd, char *module, int enable)
4424 {
4425 char *func;
4426 int ret;
4427
4428 /* match_records() modifies func, and we need the original */
4429 func = kstrdup(func_orig, GFP_KERNEL);
4430 if (!func)
4431 return -ENOMEM;
4432
4433 /*
4434 * cmd == 'mod' because we only registered this func
4435 * for the 'mod' ftrace_func_command.
4436 * But if you register one func with multiple commands,
4437 * you can tell which command was used by the cmd
4438 * parameter.
4439 */
4440 ret = match_records(hash, func, strlen(func), module);
4441 kfree(func);
4442
4443 if (!ret)
4444 return cache_mod(tr, func_orig, module, enable);
4445 if (ret < 0)
4446 return ret;
4447 return 0;
4448 }
4449
4450 static struct ftrace_func_command ftrace_mod_cmd = {
4451 .name = "mod",
4452 .func = ftrace_mod_callback,
4453 };
4454
ftrace_mod_cmd_init(void)4455 static int __init ftrace_mod_cmd_init(void)
4456 {
4457 return register_ftrace_command(&ftrace_mod_cmd);
4458 }
4459 core_initcall(ftrace_mod_cmd_init);
4460
function_trace_probe_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)4461 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4462 struct ftrace_ops *op, struct ftrace_regs *fregs)
4463 {
4464 struct ftrace_probe_ops *probe_ops;
4465 struct ftrace_func_probe *probe;
4466
4467 probe = container_of(op, struct ftrace_func_probe, ops);
4468 probe_ops = probe->probe_ops;
4469
4470 /*
4471 * Disable preemption for these calls to prevent a RCU grace
4472 * period. This syncs the hash iteration and freeing of items
4473 * on the hash. rcu_read_lock is too dangerous here.
4474 */
4475 preempt_disable_notrace();
4476 probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4477 preempt_enable_notrace();
4478 }
4479
4480 struct ftrace_func_map {
4481 struct ftrace_func_entry entry;
4482 void *data;
4483 };
4484
4485 struct ftrace_func_mapper {
4486 struct ftrace_hash hash;
4487 };
4488
4489 /**
4490 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4491 *
4492 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4493 */
allocate_ftrace_func_mapper(void)4494 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4495 {
4496 struct ftrace_hash *hash;
4497
4498 /*
4499 * The mapper is simply a ftrace_hash, but since the entries
4500 * in the hash are not ftrace_func_entry type, we define it
4501 * as a separate structure.
4502 */
4503 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4504 return (struct ftrace_func_mapper *)hash;
4505 }
4506
4507 /**
4508 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4509 * @mapper: The mapper that has the ip maps
4510 * @ip: the instruction pointer to find the data for
4511 *
4512 * Returns the data mapped to @ip if found otherwise NULL. The return
4513 * is actually the address of the mapper data pointer. The address is
4514 * returned for use cases where the data is no bigger than a long, and
4515 * the user can use the data pointer as its data instead of having to
4516 * allocate more memory for the reference.
4517 */
ftrace_func_mapper_find_ip(struct ftrace_func_mapper * mapper,unsigned long ip)4518 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4519 unsigned long ip)
4520 {
4521 struct ftrace_func_entry *entry;
4522 struct ftrace_func_map *map;
4523
4524 entry = ftrace_lookup_ip(&mapper->hash, ip);
4525 if (!entry)
4526 return NULL;
4527
4528 map = (struct ftrace_func_map *)entry;
4529 return &map->data;
4530 }
4531
4532 /**
4533 * ftrace_func_mapper_add_ip - Map some data to an ip
4534 * @mapper: The mapper that has the ip maps
4535 * @ip: The instruction pointer address to map @data to
4536 * @data: The data to map to @ip
4537 *
4538 * Returns 0 on success otherwise an error.
4539 */
ftrace_func_mapper_add_ip(struct ftrace_func_mapper * mapper,unsigned long ip,void * data)4540 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4541 unsigned long ip, void *data)
4542 {
4543 struct ftrace_func_entry *entry;
4544 struct ftrace_func_map *map;
4545
4546 entry = ftrace_lookup_ip(&mapper->hash, ip);
4547 if (entry)
4548 return -EBUSY;
4549
4550 map = kmalloc(sizeof(*map), GFP_KERNEL);
4551 if (!map)
4552 return -ENOMEM;
4553
4554 map->entry.ip = ip;
4555 map->data = data;
4556
4557 __add_hash_entry(&mapper->hash, &map->entry);
4558
4559 return 0;
4560 }
4561
4562 /**
4563 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4564 * @mapper: The mapper that has the ip maps
4565 * @ip: The instruction pointer address to remove the data from
4566 *
4567 * Returns the data if it is found, otherwise NULL.
4568 * Note, if the data pointer is used as the data itself, (see
4569 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4570 * if the data pointer was set to zero.
4571 */
ftrace_func_mapper_remove_ip(struct ftrace_func_mapper * mapper,unsigned long ip)4572 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4573 unsigned long ip)
4574 {
4575 struct ftrace_func_entry *entry;
4576 struct ftrace_func_map *map;
4577 void *data;
4578
4579 entry = ftrace_lookup_ip(&mapper->hash, ip);
4580 if (!entry)
4581 return NULL;
4582
4583 map = (struct ftrace_func_map *)entry;
4584 data = map->data;
4585
4586 remove_hash_entry(&mapper->hash, entry);
4587 kfree(entry);
4588
4589 return data;
4590 }
4591
4592 /**
4593 * free_ftrace_func_mapper - free a mapping of ips and data
4594 * @mapper: The mapper that has the ip maps
4595 * @free_func: A function to be called on each data item.
4596 *
4597 * This is used to free the function mapper. The @free_func is optional
4598 * and can be used if the data needs to be freed as well.
4599 */
free_ftrace_func_mapper(struct ftrace_func_mapper * mapper,ftrace_mapper_func free_func)4600 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4601 ftrace_mapper_func free_func)
4602 {
4603 struct ftrace_func_entry *entry;
4604 struct ftrace_func_map *map;
4605 struct hlist_head *hhd;
4606 int size, i;
4607
4608 if (!mapper)
4609 return;
4610
4611 if (free_func && mapper->hash.count) {
4612 size = 1 << mapper->hash.size_bits;
4613 for (i = 0; i < size; i++) {
4614 hhd = &mapper->hash.buckets[i];
4615 hlist_for_each_entry(entry, hhd, hlist) {
4616 map = (struct ftrace_func_map *)entry;
4617 free_func(map);
4618 }
4619 }
4620 }
4621 free_ftrace_hash(&mapper->hash);
4622 }
4623
release_probe(struct ftrace_func_probe * probe)4624 static void release_probe(struct ftrace_func_probe *probe)
4625 {
4626 struct ftrace_probe_ops *probe_ops;
4627
4628 mutex_lock(&ftrace_lock);
4629
4630 WARN_ON(probe->ref <= 0);
4631
4632 /* Subtract the ref that was used to protect this instance */
4633 probe->ref--;
4634
4635 if (!probe->ref) {
4636 probe_ops = probe->probe_ops;
4637 /*
4638 * Sending zero as ip tells probe_ops to free
4639 * the probe->data itself
4640 */
4641 if (probe_ops->free)
4642 probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4643 list_del(&probe->list);
4644 kfree(probe);
4645 }
4646 mutex_unlock(&ftrace_lock);
4647 }
4648
acquire_probe_locked(struct ftrace_func_probe * probe)4649 static void acquire_probe_locked(struct ftrace_func_probe *probe)
4650 {
4651 /*
4652 * Add one ref to keep it from being freed when releasing the
4653 * ftrace_lock mutex.
4654 */
4655 probe->ref++;
4656 }
4657
4658 int
register_ftrace_function_probe(char * glob,struct trace_array * tr,struct ftrace_probe_ops * probe_ops,void * data)4659 register_ftrace_function_probe(char *glob, struct trace_array *tr,
4660 struct ftrace_probe_ops *probe_ops,
4661 void *data)
4662 {
4663 struct ftrace_func_probe *probe = NULL, *iter;
4664 struct ftrace_func_entry *entry;
4665 struct ftrace_hash **orig_hash;
4666 struct ftrace_hash *old_hash;
4667 struct ftrace_hash *hash;
4668 int count = 0;
4669 int size;
4670 int ret;
4671 int i;
4672
4673 if (WARN_ON(!tr))
4674 return -EINVAL;
4675
4676 /* We do not support '!' for function probes */
4677 if (WARN_ON(glob[0] == '!'))
4678 return -EINVAL;
4679
4680
4681 mutex_lock(&ftrace_lock);
4682 /* Check if the probe_ops is already registered */
4683 list_for_each_entry(iter, &tr->func_probes, list) {
4684 if (iter->probe_ops == probe_ops) {
4685 probe = iter;
4686 break;
4687 }
4688 }
4689 if (!probe) {
4690 probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4691 if (!probe) {
4692 mutex_unlock(&ftrace_lock);
4693 return -ENOMEM;
4694 }
4695 probe->probe_ops = probe_ops;
4696 probe->ops.func = function_trace_probe_call;
4697 probe->tr = tr;
4698 ftrace_ops_init(&probe->ops);
4699 list_add(&probe->list, &tr->func_probes);
4700 }
4701
4702 acquire_probe_locked(probe);
4703
4704 mutex_unlock(&ftrace_lock);
4705
4706 /*
4707 * Note, there's a small window here that the func_hash->filter_hash
4708 * may be NULL or empty. Need to be careful when reading the loop.
4709 */
4710 mutex_lock(&probe->ops.func_hash->regex_lock);
4711
4712 orig_hash = &probe->ops.func_hash->filter_hash;
4713 old_hash = *orig_hash;
4714 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4715
4716 if (!hash) {
4717 ret = -ENOMEM;
4718 goto out;
4719 }
4720
4721 ret = ftrace_match_records(hash, glob, strlen(glob));
4722
4723 /* Nothing found? */
4724 if (!ret)
4725 ret = -EINVAL;
4726
4727 if (ret < 0)
4728 goto out;
4729
4730 size = 1 << hash->size_bits;
4731 for (i = 0; i < size; i++) {
4732 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4733 if (ftrace_lookup_ip(old_hash, entry->ip))
4734 continue;
4735 /*
4736 * The caller might want to do something special
4737 * for each function we find. We call the callback
4738 * to give the caller an opportunity to do so.
4739 */
4740 if (probe_ops->init) {
4741 ret = probe_ops->init(probe_ops, tr,
4742 entry->ip, data,
4743 &probe->data);
4744 if (ret < 0) {
4745 if (probe_ops->free && count)
4746 probe_ops->free(probe_ops, tr,
4747 0, probe->data);
4748 probe->data = NULL;
4749 goto out;
4750 }
4751 }
4752 count++;
4753 }
4754 }
4755
4756 mutex_lock(&ftrace_lock);
4757
4758 if (!count) {
4759 /* Nothing was added? */
4760 ret = -EINVAL;
4761 goto out_unlock;
4762 }
4763
4764 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4765 hash, 1);
4766 if (ret < 0)
4767 goto err_unlock;
4768
4769 /* One ref for each new function traced */
4770 probe->ref += count;
4771
4772 if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4773 ret = ftrace_startup(&probe->ops, 0);
4774
4775 out_unlock:
4776 mutex_unlock(&ftrace_lock);
4777
4778 if (!ret)
4779 ret = count;
4780 out:
4781 mutex_unlock(&probe->ops.func_hash->regex_lock);
4782 free_ftrace_hash(hash);
4783
4784 release_probe(probe);
4785
4786 return ret;
4787
4788 err_unlock:
4789 if (!probe_ops->free || !count)
4790 goto out_unlock;
4791
4792 /* Failed to do the move, need to call the free functions */
4793 for (i = 0; i < size; i++) {
4794 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4795 if (ftrace_lookup_ip(old_hash, entry->ip))
4796 continue;
4797 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4798 }
4799 }
4800 goto out_unlock;
4801 }
4802
4803 int
unregister_ftrace_function_probe_func(char * glob,struct trace_array * tr,struct ftrace_probe_ops * probe_ops)4804 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4805 struct ftrace_probe_ops *probe_ops)
4806 {
4807 struct ftrace_func_probe *probe = NULL, *iter;
4808 struct ftrace_ops_hash old_hash_ops;
4809 struct ftrace_func_entry *entry;
4810 struct ftrace_glob func_g;
4811 struct ftrace_hash **orig_hash;
4812 struct ftrace_hash *old_hash;
4813 struct ftrace_hash *hash = NULL;
4814 struct hlist_node *tmp;
4815 struct hlist_head hhd;
4816 char str[KSYM_SYMBOL_LEN];
4817 int count = 0;
4818 int i, ret = -ENODEV;
4819 int size;
4820
4821 if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4822 func_g.search = NULL;
4823 else {
4824 int not;
4825
4826 func_g.type = filter_parse_regex(glob, strlen(glob),
4827 &func_g.search, ¬);
4828 func_g.len = strlen(func_g.search);
4829
4830 /* we do not support '!' for function probes */
4831 if (WARN_ON(not))
4832 return -EINVAL;
4833 }
4834
4835 mutex_lock(&ftrace_lock);
4836 /* Check if the probe_ops is already registered */
4837 list_for_each_entry(iter, &tr->func_probes, list) {
4838 if (iter->probe_ops == probe_ops) {
4839 probe = iter;
4840 break;
4841 }
4842 }
4843 if (!probe)
4844 goto err_unlock_ftrace;
4845
4846 ret = -EINVAL;
4847 if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4848 goto err_unlock_ftrace;
4849
4850 acquire_probe_locked(probe);
4851
4852 mutex_unlock(&ftrace_lock);
4853
4854 mutex_lock(&probe->ops.func_hash->regex_lock);
4855
4856 orig_hash = &probe->ops.func_hash->filter_hash;
4857 old_hash = *orig_hash;
4858
4859 if (ftrace_hash_empty(old_hash))
4860 goto out_unlock;
4861
4862 old_hash_ops.filter_hash = old_hash;
4863 /* Probes only have filters */
4864 old_hash_ops.notrace_hash = NULL;
4865
4866 ret = -ENOMEM;
4867 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4868 if (!hash)
4869 goto out_unlock;
4870
4871 INIT_HLIST_HEAD(&hhd);
4872
4873 size = 1 << hash->size_bits;
4874 for (i = 0; i < size; i++) {
4875 hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4876
4877 if (func_g.search) {
4878 kallsyms_lookup(entry->ip, NULL, NULL,
4879 NULL, str);
4880 if (!ftrace_match(str, &func_g))
4881 continue;
4882 }
4883 count++;
4884 remove_hash_entry(hash, entry);
4885 hlist_add_head(&entry->hlist, &hhd);
4886 }
4887 }
4888
4889 /* Nothing found? */
4890 if (!count) {
4891 ret = -EINVAL;
4892 goto out_unlock;
4893 }
4894
4895 mutex_lock(&ftrace_lock);
4896
4897 WARN_ON(probe->ref < count);
4898
4899 probe->ref -= count;
4900
4901 if (ftrace_hash_empty(hash))
4902 ftrace_shutdown(&probe->ops, 0);
4903
4904 ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4905 hash, 1);
4906
4907 /* still need to update the function call sites */
4908 if (ftrace_enabled && !ftrace_hash_empty(hash))
4909 ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4910 &old_hash_ops);
4911 synchronize_rcu();
4912
4913 hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4914 hlist_del(&entry->hlist);
4915 if (probe_ops->free)
4916 probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4917 kfree(entry);
4918 }
4919 mutex_unlock(&ftrace_lock);
4920
4921 out_unlock:
4922 mutex_unlock(&probe->ops.func_hash->regex_lock);
4923 free_ftrace_hash(hash);
4924
4925 release_probe(probe);
4926
4927 return ret;
4928
4929 err_unlock_ftrace:
4930 mutex_unlock(&ftrace_lock);
4931 return ret;
4932 }
4933
clear_ftrace_function_probes(struct trace_array * tr)4934 void clear_ftrace_function_probes(struct trace_array *tr)
4935 {
4936 struct ftrace_func_probe *probe, *n;
4937
4938 list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4939 unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4940 }
4941
4942 static LIST_HEAD(ftrace_commands);
4943 static DEFINE_MUTEX(ftrace_cmd_mutex);
4944
4945 /*
4946 * Currently we only register ftrace commands from __init, so mark this
4947 * __init too.
4948 */
register_ftrace_command(struct ftrace_func_command * cmd)4949 __init int register_ftrace_command(struct ftrace_func_command *cmd)
4950 {
4951 struct ftrace_func_command *p;
4952 int ret = 0;
4953
4954 mutex_lock(&ftrace_cmd_mutex);
4955 list_for_each_entry(p, &ftrace_commands, list) {
4956 if (strcmp(cmd->name, p->name) == 0) {
4957 ret = -EBUSY;
4958 goto out_unlock;
4959 }
4960 }
4961 list_add(&cmd->list, &ftrace_commands);
4962 out_unlock:
4963 mutex_unlock(&ftrace_cmd_mutex);
4964
4965 return ret;
4966 }
4967
4968 /*
4969 * Currently we only unregister ftrace commands from __init, so mark
4970 * this __init too.
4971 */
unregister_ftrace_command(struct ftrace_func_command * cmd)4972 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4973 {
4974 struct ftrace_func_command *p, *n;
4975 int ret = -ENODEV;
4976
4977 mutex_lock(&ftrace_cmd_mutex);
4978 list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4979 if (strcmp(cmd->name, p->name) == 0) {
4980 ret = 0;
4981 list_del_init(&p->list);
4982 goto out_unlock;
4983 }
4984 }
4985 out_unlock:
4986 mutex_unlock(&ftrace_cmd_mutex);
4987
4988 return ret;
4989 }
4990
ftrace_process_regex(struct ftrace_iterator * iter,char * buff,int len,int enable)4991 static int ftrace_process_regex(struct ftrace_iterator *iter,
4992 char *buff, int len, int enable)
4993 {
4994 struct ftrace_hash *hash = iter->hash;
4995 struct trace_array *tr = iter->ops->private;
4996 char *func, *command, *next = buff;
4997 struct ftrace_func_command *p;
4998 int ret = -EINVAL;
4999
5000 func = strsep(&next, ":");
5001
5002 if (!next) {
5003 ret = ftrace_match_records(hash, func, len);
5004 if (!ret)
5005 ret = -EINVAL;
5006 if (ret < 0)
5007 return ret;
5008 return 0;
5009 }
5010
5011 /* command found */
5012
5013 command = strsep(&next, ":");
5014
5015 mutex_lock(&ftrace_cmd_mutex);
5016 list_for_each_entry(p, &ftrace_commands, list) {
5017 if (strcmp(p->name, command) == 0) {
5018 ret = p->func(tr, hash, func, command, next, enable);
5019 goto out_unlock;
5020 }
5021 }
5022 out_unlock:
5023 mutex_unlock(&ftrace_cmd_mutex);
5024
5025 return ret;
5026 }
5027
5028 static ssize_t
ftrace_regex_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos,int enable)5029 ftrace_regex_write(struct file *file, const char __user *ubuf,
5030 size_t cnt, loff_t *ppos, int enable)
5031 {
5032 struct ftrace_iterator *iter;
5033 struct trace_parser *parser;
5034 ssize_t ret, read;
5035
5036 if (!cnt)
5037 return 0;
5038
5039 if (file->f_mode & FMODE_READ) {
5040 struct seq_file *m = file->private_data;
5041 iter = m->private;
5042 } else
5043 iter = file->private_data;
5044
5045 if (unlikely(ftrace_disabled))
5046 return -ENODEV;
5047
5048 /* iter->hash is a local copy, so we don't need regex_lock */
5049
5050 parser = &iter->parser;
5051 read = trace_get_user(parser, ubuf, cnt, ppos);
5052
5053 if (read >= 0 && trace_parser_loaded(parser) &&
5054 !trace_parser_cont(parser)) {
5055 ret = ftrace_process_regex(iter, parser->buffer,
5056 parser->idx, enable);
5057 trace_parser_clear(parser);
5058 if (ret < 0)
5059 goto out;
5060 }
5061
5062 ret = read;
5063 out:
5064 return ret;
5065 }
5066
5067 ssize_t
ftrace_filter_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)5068 ftrace_filter_write(struct file *file, const char __user *ubuf,
5069 size_t cnt, loff_t *ppos)
5070 {
5071 return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5072 }
5073
5074 ssize_t
ftrace_notrace_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)5075 ftrace_notrace_write(struct file *file, const char __user *ubuf,
5076 size_t cnt, loff_t *ppos)
5077 {
5078 return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5079 }
5080
5081 static int
__ftrace_match_addr(struct ftrace_hash * hash,unsigned long ip,int remove)5082 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5083 {
5084 struct ftrace_func_entry *entry;
5085
5086 ip = ftrace_location(ip);
5087 if (!ip)
5088 return -EINVAL;
5089
5090 if (remove) {
5091 entry = ftrace_lookup_ip(hash, ip);
5092 if (!entry)
5093 return -ENOENT;
5094 free_hash_entry(hash, entry);
5095 return 0;
5096 }
5097
5098 return add_hash_entry(hash, ip);
5099 }
5100
5101 static int
ftrace_match_addr(struct ftrace_hash * hash,unsigned long * ips,unsigned int cnt,int remove)5102 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5103 unsigned int cnt, int remove)
5104 {
5105 unsigned int i;
5106 int err;
5107
5108 for (i = 0; i < cnt; i++) {
5109 err = __ftrace_match_addr(hash, ips[i], remove);
5110 if (err) {
5111 /*
5112 * This expects the @hash is a temporary hash and if this
5113 * fails the caller must free the @hash.
5114 */
5115 return err;
5116 }
5117 }
5118 return 0;
5119 }
5120
5121 static int
ftrace_set_hash(struct ftrace_ops * ops,unsigned char * buf,int len,unsigned long * ips,unsigned int cnt,int remove,int reset,int enable)5122 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5123 unsigned long *ips, unsigned int cnt,
5124 int remove, int reset, int enable)
5125 {
5126 struct ftrace_hash **orig_hash;
5127 struct ftrace_hash *hash;
5128 int ret;
5129
5130 if (unlikely(ftrace_disabled))
5131 return -ENODEV;
5132
5133 mutex_lock(&ops->func_hash->regex_lock);
5134
5135 if (enable)
5136 orig_hash = &ops->func_hash->filter_hash;
5137 else
5138 orig_hash = &ops->func_hash->notrace_hash;
5139
5140 if (reset)
5141 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5142 else
5143 hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5144
5145 if (!hash) {
5146 ret = -ENOMEM;
5147 goto out_regex_unlock;
5148 }
5149
5150 if (buf && !ftrace_match_records(hash, buf, len)) {
5151 ret = -EINVAL;
5152 goto out_regex_unlock;
5153 }
5154 if (ips) {
5155 ret = ftrace_match_addr(hash, ips, cnt, remove);
5156 if (ret < 0)
5157 goto out_regex_unlock;
5158 }
5159
5160 mutex_lock(&ftrace_lock);
5161 ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5162 mutex_unlock(&ftrace_lock);
5163
5164 out_regex_unlock:
5165 mutex_unlock(&ops->func_hash->regex_lock);
5166
5167 free_ftrace_hash(hash);
5168 return ret;
5169 }
5170
5171 static int
ftrace_set_addr(struct ftrace_ops * ops,unsigned long * ips,unsigned int cnt,int remove,int reset,int enable)5172 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5173 int remove, int reset, int enable)
5174 {
5175 return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5176 }
5177
5178 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5179
5180 struct ftrace_direct_func {
5181 struct list_head next;
5182 unsigned long addr;
5183 int count;
5184 };
5185
5186 static LIST_HEAD(ftrace_direct_funcs);
5187
5188 /**
5189 * ftrace_find_direct_func - test an address if it is a registered direct caller
5190 * @addr: The address of a registered direct caller
5191 *
5192 * This searches to see if a ftrace direct caller has been registered
5193 * at a specific address, and if so, it returns a descriptor for it.
5194 *
5195 * This can be used by architecture code to see if an address is
5196 * a direct caller (trampoline) attached to a fentry/mcount location.
5197 * This is useful for the function_graph tracer, as it may need to
5198 * do adjustments if it traced a location that also has a direct
5199 * trampoline attached to it.
5200 */
ftrace_find_direct_func(unsigned long addr)5201 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5202 {
5203 struct ftrace_direct_func *entry;
5204 bool found = false;
5205
5206 /* May be called by fgraph trampoline (protected by rcu tasks) */
5207 list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5208 if (entry->addr == addr) {
5209 found = true;
5210 break;
5211 }
5212 }
5213 if (found)
5214 return entry;
5215
5216 return NULL;
5217 }
5218
ftrace_alloc_direct_func(unsigned long addr)5219 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5220 {
5221 struct ftrace_direct_func *direct;
5222
5223 direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5224 if (!direct)
5225 return NULL;
5226 direct->addr = addr;
5227 direct->count = 0;
5228 list_add_rcu(&direct->next, &ftrace_direct_funcs);
5229 ftrace_direct_func_count++;
5230 return direct;
5231 }
5232
5233 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5234
5235 /**
5236 * register_ftrace_direct - Call a custom trampoline directly
5237 * @ip: The address of the nop at the beginning of a function
5238 * @addr: The address of the trampoline to call at @ip
5239 *
5240 * This is used to connect a direct call from the nop location (@ip)
5241 * at the start of ftrace traced functions. The location that it calls
5242 * (@addr) must be able to handle a direct call, and save the parameters
5243 * of the function being traced, and restore them (or inject new ones
5244 * if needed), before returning.
5245 *
5246 * Returns:
5247 * 0 on success
5248 * -EBUSY - Another direct function is already attached (there can be only one)
5249 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5250 * -ENOMEM - There was an allocation failure.
5251 */
register_ftrace_direct(unsigned long ip,unsigned long addr)5252 int register_ftrace_direct(unsigned long ip, unsigned long addr)
5253 {
5254 struct ftrace_direct_func *direct;
5255 struct ftrace_func_entry *entry;
5256 struct ftrace_hash *free_hash = NULL;
5257 struct dyn_ftrace *rec;
5258 int ret = -ENODEV;
5259
5260 mutex_lock(&direct_mutex);
5261
5262 ip = ftrace_location(ip);
5263 if (!ip)
5264 goto out_unlock;
5265
5266 /* See if there's a direct function at @ip already */
5267 ret = -EBUSY;
5268 if (ftrace_find_rec_direct(ip))
5269 goto out_unlock;
5270
5271 ret = -ENODEV;
5272 rec = lookup_rec(ip, ip);
5273 if (!rec)
5274 goto out_unlock;
5275
5276 /*
5277 * Check if the rec says it has a direct call but we didn't
5278 * find one earlier?
5279 */
5280 if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5281 goto out_unlock;
5282
5283 /* Make sure the ip points to the exact record */
5284 if (ip != rec->ip) {
5285 ip = rec->ip;
5286 /* Need to check this ip for a direct. */
5287 if (ftrace_find_rec_direct(ip))
5288 goto out_unlock;
5289 }
5290
5291 ret = -ENOMEM;
5292 direct = ftrace_find_direct_func(addr);
5293 if (!direct) {
5294 direct = ftrace_alloc_direct_func(addr);
5295 if (!direct)
5296 goto out_unlock;
5297 }
5298
5299 entry = ftrace_add_rec_direct(ip, addr, &free_hash);
5300 if (!entry)
5301 goto out_unlock;
5302
5303 ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
5304
5305 if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5306 ret = register_ftrace_function_nolock(&direct_ops);
5307 if (ret)
5308 ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5309 }
5310
5311 if (ret) {
5312 remove_hash_entry(direct_functions, entry);
5313 kfree(entry);
5314 if (!direct->count) {
5315 list_del_rcu(&direct->next);
5316 synchronize_rcu_tasks();
5317 kfree(direct);
5318 if (free_hash)
5319 free_ftrace_hash(free_hash);
5320 free_hash = NULL;
5321 ftrace_direct_func_count--;
5322 }
5323 } else {
5324 direct->count++;
5325 }
5326 out_unlock:
5327 mutex_unlock(&direct_mutex);
5328
5329 if (free_hash) {
5330 synchronize_rcu_tasks();
5331 free_ftrace_hash(free_hash);
5332 }
5333
5334 return ret;
5335 }
5336 EXPORT_SYMBOL_GPL(register_ftrace_direct);
5337
find_direct_entry(unsigned long * ip,struct dyn_ftrace ** recp)5338 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5339 struct dyn_ftrace **recp)
5340 {
5341 struct ftrace_func_entry *entry;
5342 struct dyn_ftrace *rec;
5343
5344 rec = lookup_rec(*ip, *ip);
5345 if (!rec)
5346 return NULL;
5347
5348 entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5349 if (!entry) {
5350 WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5351 return NULL;
5352 }
5353
5354 WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5355
5356 /* Passed in ip just needs to be on the call site */
5357 *ip = rec->ip;
5358
5359 if (recp)
5360 *recp = rec;
5361
5362 return entry;
5363 }
5364
unregister_ftrace_direct(unsigned long ip,unsigned long addr)5365 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5366 {
5367 struct ftrace_direct_func *direct;
5368 struct ftrace_func_entry *entry;
5369 struct ftrace_hash *hash;
5370 int ret = -ENODEV;
5371
5372 mutex_lock(&direct_mutex);
5373
5374 ip = ftrace_location(ip);
5375 if (!ip)
5376 goto out_unlock;
5377
5378 entry = find_direct_entry(&ip, NULL);
5379 if (!entry)
5380 goto out_unlock;
5381
5382 hash = direct_ops.func_hash->filter_hash;
5383 if (hash->count == 1)
5384 unregister_ftrace_function(&direct_ops);
5385
5386 ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5387
5388 WARN_ON(ret);
5389
5390 remove_hash_entry(direct_functions, entry);
5391
5392 direct = ftrace_find_direct_func(addr);
5393 if (!WARN_ON(!direct)) {
5394 /* This is the good path (see the ! before WARN) */
5395 direct->count--;
5396 WARN_ON(direct->count < 0);
5397 if (!direct->count) {
5398 list_del_rcu(&direct->next);
5399 synchronize_rcu_tasks();
5400 kfree(direct);
5401 kfree(entry);
5402 ftrace_direct_func_count--;
5403 }
5404 }
5405 out_unlock:
5406 mutex_unlock(&direct_mutex);
5407
5408 return ret;
5409 }
5410 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5411
5412 static struct ftrace_ops stub_ops = {
5413 .func = ftrace_stub,
5414 };
5415
5416 /**
5417 * ftrace_modify_direct_caller - modify ftrace nop directly
5418 * @entry: The ftrace hash entry of the direct helper for @rec
5419 * @rec: The record representing the function site to patch
5420 * @old_addr: The location that the site at @rec->ip currently calls
5421 * @new_addr: The location that the site at @rec->ip should call
5422 *
5423 * An architecture may overwrite this function to optimize the
5424 * changing of the direct callback on an ftrace nop location.
5425 * This is called with the ftrace_lock mutex held, and no other
5426 * ftrace callbacks are on the associated record (@rec). Thus,
5427 * it is safe to modify the ftrace record, where it should be
5428 * currently calling @old_addr directly, to call @new_addr.
5429 *
5430 * This is called with direct_mutex locked.
5431 *
5432 * Safety checks should be made to make sure that the code at
5433 * @rec->ip is currently calling @old_addr. And this must
5434 * also update entry->direct to @new_addr.
5435 */
ftrace_modify_direct_caller(struct ftrace_func_entry * entry,struct dyn_ftrace * rec,unsigned long old_addr,unsigned long new_addr)5436 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5437 struct dyn_ftrace *rec,
5438 unsigned long old_addr,
5439 unsigned long new_addr)
5440 {
5441 unsigned long ip = rec->ip;
5442 int ret;
5443
5444 lockdep_assert_held(&direct_mutex);
5445
5446 /*
5447 * The ftrace_lock was used to determine if the record
5448 * had more than one registered user to it. If it did,
5449 * we needed to prevent that from changing to do the quick
5450 * switch. But if it did not (only a direct caller was attached)
5451 * then this function is called. But this function can deal
5452 * with attached callers to the rec that we care about, and
5453 * since this function uses standard ftrace calls that take
5454 * the ftrace_lock mutex, we need to release it.
5455 */
5456 mutex_unlock(&ftrace_lock);
5457
5458 /*
5459 * By setting a stub function at the same address, we force
5460 * the code to call the iterator and the direct_ops helper.
5461 * This means that @ip does not call the direct call, and
5462 * we can simply modify it.
5463 */
5464 ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5465 if (ret)
5466 goto out_lock;
5467
5468 ret = register_ftrace_function_nolock(&stub_ops);
5469 if (ret) {
5470 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5471 goto out_lock;
5472 }
5473
5474 entry->direct = new_addr;
5475
5476 /*
5477 * By removing the stub, we put back the direct call, calling
5478 * the @new_addr.
5479 */
5480 unregister_ftrace_function(&stub_ops);
5481 ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5482
5483 out_lock:
5484 mutex_lock(&ftrace_lock);
5485
5486 return ret;
5487 }
5488
5489 /**
5490 * modify_ftrace_direct - Modify an existing direct call to call something else
5491 * @ip: The instruction pointer to modify
5492 * @old_addr: The address that the current @ip calls directly
5493 * @new_addr: The address that the @ip should call
5494 *
5495 * This modifies a ftrace direct caller at an instruction pointer without
5496 * having to disable it first. The direct call will switch over to the
5497 * @new_addr without missing anything.
5498 *
5499 * Returns: zero on success. Non zero on error, which includes:
5500 * -ENODEV : the @ip given has no direct caller attached
5501 * -EINVAL : the @old_addr does not match the current direct caller
5502 */
modify_ftrace_direct(unsigned long ip,unsigned long old_addr,unsigned long new_addr)5503 int modify_ftrace_direct(unsigned long ip,
5504 unsigned long old_addr, unsigned long new_addr)
5505 {
5506 struct ftrace_direct_func *direct, *new_direct = NULL;
5507 struct ftrace_func_entry *entry;
5508 struct dyn_ftrace *rec;
5509 int ret = -ENODEV;
5510
5511 mutex_lock(&direct_mutex);
5512
5513 mutex_lock(&ftrace_lock);
5514
5515 ip = ftrace_location(ip);
5516 if (!ip)
5517 goto out_unlock;
5518
5519 entry = find_direct_entry(&ip, &rec);
5520 if (!entry)
5521 goto out_unlock;
5522
5523 ret = -EINVAL;
5524 if (entry->direct != old_addr)
5525 goto out_unlock;
5526
5527 direct = ftrace_find_direct_func(old_addr);
5528 if (WARN_ON(!direct))
5529 goto out_unlock;
5530 if (direct->count > 1) {
5531 ret = -ENOMEM;
5532 new_direct = ftrace_alloc_direct_func(new_addr);
5533 if (!new_direct)
5534 goto out_unlock;
5535 direct->count--;
5536 new_direct->count++;
5537 } else {
5538 direct->addr = new_addr;
5539 }
5540
5541 /*
5542 * If there's no other ftrace callback on the rec->ip location,
5543 * then it can be changed directly by the architecture.
5544 * If there is another caller, then we just need to change the
5545 * direct caller helper to point to @new_addr.
5546 */
5547 if (ftrace_rec_count(rec) == 1) {
5548 ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5549 } else {
5550 entry->direct = new_addr;
5551 ret = 0;
5552 }
5553
5554 if (unlikely(ret && new_direct)) {
5555 direct->count++;
5556 list_del_rcu(&new_direct->next);
5557 synchronize_rcu_tasks();
5558 kfree(new_direct);
5559 ftrace_direct_func_count--;
5560 }
5561
5562 out_unlock:
5563 mutex_unlock(&ftrace_lock);
5564 mutex_unlock(&direct_mutex);
5565 return ret;
5566 }
5567 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5568
5569 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5570
check_direct_multi(struct ftrace_ops * ops)5571 static int check_direct_multi(struct ftrace_ops *ops)
5572 {
5573 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5574 return -EINVAL;
5575 if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5576 return -EINVAL;
5577 return 0;
5578 }
5579
remove_direct_functions_hash(struct ftrace_hash * hash,unsigned long addr)5580 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5581 {
5582 struct ftrace_func_entry *entry, *del;
5583 int size, i;
5584
5585 size = 1 << hash->size_bits;
5586 for (i = 0; i < size; i++) {
5587 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5588 del = __ftrace_lookup_ip(direct_functions, entry->ip);
5589 if (del && del->direct == addr) {
5590 remove_hash_entry(direct_functions, del);
5591 kfree(del);
5592 }
5593 }
5594 }
5595 }
5596
5597 /**
5598 * register_ftrace_direct_multi - Call a custom trampoline directly
5599 * for multiple functions registered in @ops
5600 * @ops: The address of the struct ftrace_ops object
5601 * @addr: The address of the trampoline to call at @ops functions
5602 *
5603 * This is used to connect a direct calls to @addr from the nop locations
5604 * of the functions registered in @ops (with by ftrace_set_filter_ip
5605 * function).
5606 *
5607 * The location that it calls (@addr) must be able to handle a direct call,
5608 * and save the parameters of the function being traced, and restore them
5609 * (or inject new ones if needed), before returning.
5610 *
5611 * Returns:
5612 * 0 on success
5613 * -EINVAL - The @ops object was already registered with this call or
5614 * when there are no functions in @ops object.
5615 * -EBUSY - Another direct function is already attached (there can be only one)
5616 * -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5617 * -ENOMEM - There was an allocation failure.
5618 */
register_ftrace_direct_multi(struct ftrace_ops * ops,unsigned long addr)5619 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5620 {
5621 struct ftrace_hash *hash, *free_hash = NULL;
5622 struct ftrace_func_entry *entry, *new;
5623 int err = -EBUSY, size, i;
5624
5625 if (ops->func || ops->trampoline)
5626 return -EINVAL;
5627 if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5628 return -EINVAL;
5629 if (ops->flags & FTRACE_OPS_FL_ENABLED)
5630 return -EINVAL;
5631
5632 hash = ops->func_hash->filter_hash;
5633 if (ftrace_hash_empty(hash))
5634 return -EINVAL;
5635
5636 mutex_lock(&direct_mutex);
5637
5638 /* Make sure requested entries are not already registered.. */
5639 size = 1 << hash->size_bits;
5640 for (i = 0; i < size; i++) {
5641 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5642 if (ftrace_find_rec_direct(entry->ip))
5643 goto out_unlock;
5644 }
5645 }
5646
5647 /* ... and insert them to direct_functions hash. */
5648 err = -ENOMEM;
5649 for (i = 0; i < size; i++) {
5650 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5651 new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5652 if (!new)
5653 goto out_remove;
5654 entry->direct = addr;
5655 }
5656 }
5657
5658 ops->func = call_direct_funcs;
5659 ops->flags = MULTI_FLAGS;
5660 ops->trampoline = FTRACE_REGS_ADDR;
5661
5662 err = register_ftrace_function_nolock(ops);
5663
5664 out_remove:
5665 if (err)
5666 remove_direct_functions_hash(hash, addr);
5667
5668 out_unlock:
5669 mutex_unlock(&direct_mutex);
5670
5671 if (free_hash) {
5672 synchronize_rcu_tasks();
5673 free_ftrace_hash(free_hash);
5674 }
5675 return err;
5676 }
5677 EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
5678
5679 /**
5680 * unregister_ftrace_direct_multi - Remove calls to custom trampoline
5681 * previously registered by register_ftrace_direct_multi for @ops object.
5682 * @ops: The address of the struct ftrace_ops object
5683 *
5684 * This is used to remove a direct calls to @addr from the nop locations
5685 * of the functions registered in @ops (with by ftrace_set_filter_ip
5686 * function).
5687 *
5688 * Returns:
5689 * 0 on success
5690 * -EINVAL - The @ops object was not properly registered.
5691 */
unregister_ftrace_direct_multi(struct ftrace_ops * ops,unsigned long addr)5692 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5693 {
5694 struct ftrace_hash *hash = ops->func_hash->filter_hash;
5695 int err;
5696
5697 if (check_direct_multi(ops))
5698 return -EINVAL;
5699 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5700 return -EINVAL;
5701
5702 mutex_lock(&direct_mutex);
5703 err = unregister_ftrace_function(ops);
5704 remove_direct_functions_hash(hash, addr);
5705 mutex_unlock(&direct_mutex);
5706
5707 /* cleanup for possible another register call */
5708 ops->func = NULL;
5709 ops->trampoline = 0;
5710 return err;
5711 }
5712 EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
5713
5714 static int
__modify_ftrace_direct_multi(struct ftrace_ops * ops,unsigned long addr)5715 __modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5716 {
5717 struct ftrace_hash *hash;
5718 struct ftrace_func_entry *entry, *iter;
5719 static struct ftrace_ops tmp_ops = {
5720 .func = ftrace_stub,
5721 .flags = FTRACE_OPS_FL_STUB,
5722 };
5723 int i, size;
5724 int err;
5725
5726 lockdep_assert_held_once(&direct_mutex);
5727
5728 /* Enable the tmp_ops to have the same functions as the direct ops */
5729 ftrace_ops_init(&tmp_ops);
5730 tmp_ops.func_hash = ops->func_hash;
5731
5732 err = register_ftrace_function_nolock(&tmp_ops);
5733 if (err)
5734 return err;
5735
5736 /*
5737 * Now the ftrace_ops_list_func() is called to do the direct callers.
5738 * We can safely change the direct functions attached to each entry.
5739 */
5740 mutex_lock(&ftrace_lock);
5741
5742 hash = ops->func_hash->filter_hash;
5743 size = 1 << hash->size_bits;
5744 for (i = 0; i < size; i++) {
5745 hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5746 entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5747 if (!entry)
5748 continue;
5749 entry->direct = addr;
5750 }
5751 }
5752
5753 mutex_unlock(&ftrace_lock);
5754
5755 /* Removing the tmp_ops will add the updated direct callers to the functions */
5756 unregister_ftrace_function(&tmp_ops);
5757
5758 return err;
5759 }
5760
5761 /**
5762 * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
5763 * to call something else
5764 * @ops: The address of the struct ftrace_ops object
5765 * @addr: The address of the new trampoline to call at @ops functions
5766 *
5767 * This is used to unregister currently registered direct caller and
5768 * register new one @addr on functions registered in @ops object.
5769 *
5770 * Note there's window between ftrace_shutdown and ftrace_startup calls
5771 * where there will be no callbacks called.
5772 *
5773 * Caller should already have direct_mutex locked, so we don't lock
5774 * direct_mutex here.
5775 *
5776 * Returns: zero on success. Non zero on error, which includes:
5777 * -EINVAL - The @ops object was not properly registered.
5778 */
modify_ftrace_direct_multi_nolock(struct ftrace_ops * ops,unsigned long addr)5779 int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
5780 {
5781 if (check_direct_multi(ops))
5782 return -EINVAL;
5783 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5784 return -EINVAL;
5785
5786 return __modify_ftrace_direct_multi(ops, addr);
5787 }
5788 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
5789
5790 /**
5791 * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
5792 * to call something else
5793 * @ops: The address of the struct ftrace_ops object
5794 * @addr: The address of the new trampoline to call at @ops functions
5795 *
5796 * This is used to unregister currently registered direct caller and
5797 * register new one @addr on functions registered in @ops object.
5798 *
5799 * Note there's window between ftrace_shutdown and ftrace_startup calls
5800 * where there will be no callbacks called.
5801 *
5802 * Returns: zero on success. Non zero on error, which includes:
5803 * -EINVAL - The @ops object was not properly registered.
5804 */
modify_ftrace_direct_multi(struct ftrace_ops * ops,unsigned long addr)5805 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5806 {
5807 int err;
5808
5809 if (check_direct_multi(ops))
5810 return -EINVAL;
5811 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5812 return -EINVAL;
5813
5814 mutex_lock(&direct_mutex);
5815 err = __modify_ftrace_direct_multi(ops, addr);
5816 mutex_unlock(&direct_mutex);
5817 return err;
5818 }
5819 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
5820 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5821
5822 /**
5823 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5824 * @ops - the ops to set the filter with
5825 * @ip - the address to add to or remove from the filter.
5826 * @remove - non zero to remove the ip from the filter
5827 * @reset - non zero to reset all filters before applying this filter.
5828 *
5829 * Filters denote which functions should be enabled when tracing is enabled
5830 * If @ip is NULL, it fails to update filter.
5831 */
ftrace_set_filter_ip(struct ftrace_ops * ops,unsigned long ip,int remove,int reset)5832 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5833 int remove, int reset)
5834 {
5835 ftrace_ops_init(ops);
5836 return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5837 }
5838 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5839
5840 /**
5841 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5842 * @ops - the ops to set the filter with
5843 * @ips - the array of addresses to add to or remove from the filter.
5844 * @cnt - the number of addresses in @ips
5845 * @remove - non zero to remove ips from the filter
5846 * @reset - non zero to reset all filters before applying this filter.
5847 *
5848 * Filters denote which functions should be enabled when tracing is enabled
5849 * If @ips array or any ip specified within is NULL , it fails to update filter.
5850 */
ftrace_set_filter_ips(struct ftrace_ops * ops,unsigned long * ips,unsigned int cnt,int remove,int reset)5851 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5852 unsigned int cnt, int remove, int reset)
5853 {
5854 ftrace_ops_init(ops);
5855 return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5856 }
5857 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5858
5859 /**
5860 * ftrace_ops_set_global_filter - setup ops to use global filters
5861 * @ops - the ops which will use the global filters
5862 *
5863 * ftrace users who need global function trace filtering should call this.
5864 * It can set the global filter only if ops were not initialized before.
5865 */
ftrace_ops_set_global_filter(struct ftrace_ops * ops)5866 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5867 {
5868 if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5869 return;
5870
5871 ftrace_ops_init(ops);
5872 ops->func_hash = &global_ops.local_hash;
5873 }
5874 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5875
5876 static int
ftrace_set_regex(struct ftrace_ops * ops,unsigned char * buf,int len,int reset,int enable)5877 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5878 int reset, int enable)
5879 {
5880 return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5881 }
5882
5883 /**
5884 * ftrace_set_filter - set a function to filter on in ftrace
5885 * @ops - the ops to set the filter with
5886 * @buf - the string that holds the function filter text.
5887 * @len - the length of the string.
5888 * @reset - non zero to reset all filters before applying this filter.
5889 *
5890 * Filters denote which functions should be enabled when tracing is enabled.
5891 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5892 */
ftrace_set_filter(struct ftrace_ops * ops,unsigned char * buf,int len,int reset)5893 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5894 int len, int reset)
5895 {
5896 ftrace_ops_init(ops);
5897 return ftrace_set_regex(ops, buf, len, reset, 1);
5898 }
5899 EXPORT_SYMBOL_GPL(ftrace_set_filter);
5900
5901 /**
5902 * ftrace_set_notrace - set a function to not trace in ftrace
5903 * @ops - the ops to set the notrace filter with
5904 * @buf - the string that holds the function notrace text.
5905 * @len - the length of the string.
5906 * @reset - non zero to reset all filters before applying this filter.
5907 *
5908 * Notrace Filters denote which functions should not be enabled when tracing
5909 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5910 * for tracing.
5911 */
ftrace_set_notrace(struct ftrace_ops * ops,unsigned char * buf,int len,int reset)5912 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5913 int len, int reset)
5914 {
5915 ftrace_ops_init(ops);
5916 return ftrace_set_regex(ops, buf, len, reset, 0);
5917 }
5918 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5919 /**
5920 * ftrace_set_global_filter - set a function to filter on with global tracers
5921 * @buf - the string that holds the function filter text.
5922 * @len - the length of the string.
5923 * @reset - non zero to reset all filters before applying this filter.
5924 *
5925 * Filters denote which functions should be enabled when tracing is enabled.
5926 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5927 */
ftrace_set_global_filter(unsigned char * buf,int len,int reset)5928 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5929 {
5930 ftrace_set_regex(&global_ops, buf, len, reset, 1);
5931 }
5932 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5933
5934 /**
5935 * ftrace_set_global_notrace - set a function to not trace with global tracers
5936 * @buf - the string that holds the function notrace text.
5937 * @len - the length of the string.
5938 * @reset - non zero to reset all filters before applying this filter.
5939 *
5940 * Notrace Filters denote which functions should not be enabled when tracing
5941 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5942 * for tracing.
5943 */
ftrace_set_global_notrace(unsigned char * buf,int len,int reset)5944 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5945 {
5946 ftrace_set_regex(&global_ops, buf, len, reset, 0);
5947 }
5948 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5949
5950 /*
5951 * command line interface to allow users to set filters on boot up.
5952 */
5953 #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
5954 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5955 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5956
5957 /* Used by function selftest to not test if filter is set */
5958 bool ftrace_filter_param __initdata;
5959
set_ftrace_notrace(char * str)5960 static int __init set_ftrace_notrace(char *str)
5961 {
5962 ftrace_filter_param = true;
5963 strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5964 return 1;
5965 }
5966 __setup("ftrace_notrace=", set_ftrace_notrace);
5967
set_ftrace_filter(char * str)5968 static int __init set_ftrace_filter(char *str)
5969 {
5970 ftrace_filter_param = true;
5971 strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5972 return 1;
5973 }
5974 __setup("ftrace_filter=", set_ftrace_filter);
5975
5976 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5977 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5978 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5979 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5980
set_graph_function(char * str)5981 static int __init set_graph_function(char *str)
5982 {
5983 strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5984 return 1;
5985 }
5986 __setup("ftrace_graph_filter=", set_graph_function);
5987
set_graph_notrace_function(char * str)5988 static int __init set_graph_notrace_function(char *str)
5989 {
5990 strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5991 return 1;
5992 }
5993 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
5994
set_graph_max_depth_function(char * str)5995 static int __init set_graph_max_depth_function(char *str)
5996 {
5997 if (!str)
5998 return 0;
5999 fgraph_max_depth = simple_strtoul(str, NULL, 0);
6000 return 1;
6001 }
6002 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
6003
set_ftrace_early_graph(char * buf,int enable)6004 static void __init set_ftrace_early_graph(char *buf, int enable)
6005 {
6006 int ret;
6007 char *func;
6008 struct ftrace_hash *hash;
6009
6010 hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
6011 if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
6012 return;
6013
6014 while (buf) {
6015 func = strsep(&buf, ",");
6016 /* we allow only one expression at a time */
6017 ret = ftrace_graph_set_hash(hash, func);
6018 if (ret)
6019 printk(KERN_DEBUG "ftrace: function %s not "
6020 "traceable\n", func);
6021 }
6022
6023 if (enable)
6024 ftrace_graph_hash = hash;
6025 else
6026 ftrace_graph_notrace_hash = hash;
6027 }
6028 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6029
6030 void __init
ftrace_set_early_filter(struct ftrace_ops * ops,char * buf,int enable)6031 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
6032 {
6033 char *func;
6034
6035 ftrace_ops_init(ops);
6036
6037 while (buf) {
6038 func = strsep(&buf, ",");
6039 ftrace_set_regex(ops, func, strlen(func), 0, enable);
6040 }
6041 }
6042
set_ftrace_early_filters(void)6043 static void __init set_ftrace_early_filters(void)
6044 {
6045 if (ftrace_filter_buf[0])
6046 ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
6047 if (ftrace_notrace_buf[0])
6048 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
6049 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6050 if (ftrace_graph_buf[0])
6051 set_ftrace_early_graph(ftrace_graph_buf, 1);
6052 if (ftrace_graph_notrace_buf[0])
6053 set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
6054 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6055 }
6056
ftrace_regex_release(struct inode * inode,struct file * file)6057 int ftrace_regex_release(struct inode *inode, struct file *file)
6058 {
6059 struct seq_file *m = (struct seq_file *)file->private_data;
6060 struct ftrace_iterator *iter;
6061 struct ftrace_hash **orig_hash;
6062 struct trace_parser *parser;
6063 int filter_hash;
6064
6065 if (file->f_mode & FMODE_READ) {
6066 iter = m->private;
6067 seq_release(inode, file);
6068 } else
6069 iter = file->private_data;
6070
6071 parser = &iter->parser;
6072 if (trace_parser_loaded(parser)) {
6073 int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
6074
6075 ftrace_process_regex(iter, parser->buffer,
6076 parser->idx, enable);
6077 }
6078
6079 trace_parser_put(parser);
6080
6081 mutex_lock(&iter->ops->func_hash->regex_lock);
6082
6083 if (file->f_mode & FMODE_WRITE) {
6084 filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
6085
6086 if (filter_hash) {
6087 orig_hash = &iter->ops->func_hash->filter_hash;
6088 if (iter->tr) {
6089 if (list_empty(&iter->tr->mod_trace))
6090 iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
6091 else
6092 iter->hash->flags |= FTRACE_HASH_FL_MOD;
6093 }
6094 } else
6095 orig_hash = &iter->ops->func_hash->notrace_hash;
6096
6097 mutex_lock(&ftrace_lock);
6098 ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
6099 iter->hash, filter_hash);
6100 mutex_unlock(&ftrace_lock);
6101 } else {
6102 /* For read only, the hash is the ops hash */
6103 iter->hash = NULL;
6104 }
6105
6106 mutex_unlock(&iter->ops->func_hash->regex_lock);
6107 free_ftrace_hash(iter->hash);
6108 if (iter->tr)
6109 trace_array_put(iter->tr);
6110 kfree(iter);
6111
6112 return 0;
6113 }
6114
6115 static const struct file_operations ftrace_avail_fops = {
6116 .open = ftrace_avail_open,
6117 .read = seq_read,
6118 .llseek = seq_lseek,
6119 .release = seq_release_private,
6120 };
6121
6122 static const struct file_operations ftrace_enabled_fops = {
6123 .open = ftrace_enabled_open,
6124 .read = seq_read,
6125 .llseek = seq_lseek,
6126 .release = seq_release_private,
6127 };
6128
6129 static const struct file_operations ftrace_filter_fops = {
6130 .open = ftrace_filter_open,
6131 .read = seq_read,
6132 .write = ftrace_filter_write,
6133 .llseek = tracing_lseek,
6134 .release = ftrace_regex_release,
6135 };
6136
6137 static const struct file_operations ftrace_notrace_fops = {
6138 .open = ftrace_notrace_open,
6139 .read = seq_read,
6140 .write = ftrace_notrace_write,
6141 .llseek = tracing_lseek,
6142 .release = ftrace_regex_release,
6143 };
6144
6145 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6146
6147 static DEFINE_MUTEX(graph_lock);
6148
6149 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
6150 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
6151
6152 enum graph_filter_type {
6153 GRAPH_FILTER_NOTRACE = 0,
6154 GRAPH_FILTER_FUNCTION,
6155 };
6156
6157 #define FTRACE_GRAPH_EMPTY ((void *)1)
6158
6159 struct ftrace_graph_data {
6160 struct ftrace_hash *hash;
6161 struct ftrace_func_entry *entry;
6162 int idx; /* for hash table iteration */
6163 enum graph_filter_type type;
6164 struct ftrace_hash *new_hash;
6165 const struct seq_operations *seq_ops;
6166 struct trace_parser parser;
6167 };
6168
6169 static void *
__g_next(struct seq_file * m,loff_t * pos)6170 __g_next(struct seq_file *m, loff_t *pos)
6171 {
6172 struct ftrace_graph_data *fgd = m->private;
6173 struct ftrace_func_entry *entry = fgd->entry;
6174 struct hlist_head *head;
6175 int i, idx = fgd->idx;
6176
6177 if (*pos >= fgd->hash->count)
6178 return NULL;
6179
6180 if (entry) {
6181 hlist_for_each_entry_continue(entry, hlist) {
6182 fgd->entry = entry;
6183 return entry;
6184 }
6185
6186 idx++;
6187 }
6188
6189 for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6190 head = &fgd->hash->buckets[i];
6191 hlist_for_each_entry(entry, head, hlist) {
6192 fgd->entry = entry;
6193 fgd->idx = i;
6194 return entry;
6195 }
6196 }
6197 return NULL;
6198 }
6199
6200 static void *
g_next(struct seq_file * m,void * v,loff_t * pos)6201 g_next(struct seq_file *m, void *v, loff_t *pos)
6202 {
6203 (*pos)++;
6204 return __g_next(m, pos);
6205 }
6206
g_start(struct seq_file * m,loff_t * pos)6207 static void *g_start(struct seq_file *m, loff_t *pos)
6208 {
6209 struct ftrace_graph_data *fgd = m->private;
6210
6211 mutex_lock(&graph_lock);
6212
6213 if (fgd->type == GRAPH_FILTER_FUNCTION)
6214 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6215 lockdep_is_held(&graph_lock));
6216 else
6217 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6218 lockdep_is_held(&graph_lock));
6219
6220 /* Nothing, tell g_show to print all functions are enabled */
6221 if (ftrace_hash_empty(fgd->hash) && !*pos)
6222 return FTRACE_GRAPH_EMPTY;
6223
6224 fgd->idx = 0;
6225 fgd->entry = NULL;
6226 return __g_next(m, pos);
6227 }
6228
g_stop(struct seq_file * m,void * p)6229 static void g_stop(struct seq_file *m, void *p)
6230 {
6231 mutex_unlock(&graph_lock);
6232 }
6233
g_show(struct seq_file * m,void * v)6234 static int g_show(struct seq_file *m, void *v)
6235 {
6236 struct ftrace_func_entry *entry = v;
6237
6238 if (!entry)
6239 return 0;
6240
6241 if (entry == FTRACE_GRAPH_EMPTY) {
6242 struct ftrace_graph_data *fgd = m->private;
6243
6244 if (fgd->type == GRAPH_FILTER_FUNCTION)
6245 seq_puts(m, "#### all functions enabled ####\n");
6246 else
6247 seq_puts(m, "#### no functions disabled ####\n");
6248 return 0;
6249 }
6250
6251 seq_printf(m, "%ps\n", (void *)entry->ip);
6252
6253 return 0;
6254 }
6255
6256 static const struct seq_operations ftrace_graph_seq_ops = {
6257 .start = g_start,
6258 .next = g_next,
6259 .stop = g_stop,
6260 .show = g_show,
6261 };
6262
6263 static int
__ftrace_graph_open(struct inode * inode,struct file * file,struct ftrace_graph_data * fgd)6264 __ftrace_graph_open(struct inode *inode, struct file *file,
6265 struct ftrace_graph_data *fgd)
6266 {
6267 int ret;
6268 struct ftrace_hash *new_hash = NULL;
6269
6270 ret = security_locked_down(LOCKDOWN_TRACEFS);
6271 if (ret)
6272 return ret;
6273
6274 if (file->f_mode & FMODE_WRITE) {
6275 const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6276
6277 if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6278 return -ENOMEM;
6279
6280 if (file->f_flags & O_TRUNC)
6281 new_hash = alloc_ftrace_hash(size_bits);
6282 else
6283 new_hash = alloc_and_copy_ftrace_hash(size_bits,
6284 fgd->hash);
6285 if (!new_hash) {
6286 ret = -ENOMEM;
6287 goto out;
6288 }
6289 }
6290
6291 if (file->f_mode & FMODE_READ) {
6292 ret = seq_open(file, &ftrace_graph_seq_ops);
6293 if (!ret) {
6294 struct seq_file *m = file->private_data;
6295 m->private = fgd;
6296 } else {
6297 /* Failed */
6298 free_ftrace_hash(new_hash);
6299 new_hash = NULL;
6300 }
6301 } else
6302 file->private_data = fgd;
6303
6304 out:
6305 if (ret < 0 && file->f_mode & FMODE_WRITE)
6306 trace_parser_put(&fgd->parser);
6307
6308 fgd->new_hash = new_hash;
6309
6310 /*
6311 * All uses of fgd->hash must be taken with the graph_lock
6312 * held. The graph_lock is going to be released, so force
6313 * fgd->hash to be reinitialized when it is taken again.
6314 */
6315 fgd->hash = NULL;
6316
6317 return ret;
6318 }
6319
6320 static int
ftrace_graph_open(struct inode * inode,struct file * file)6321 ftrace_graph_open(struct inode *inode, struct file *file)
6322 {
6323 struct ftrace_graph_data *fgd;
6324 int ret;
6325
6326 if (unlikely(ftrace_disabled))
6327 return -ENODEV;
6328
6329 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6330 if (fgd == NULL)
6331 return -ENOMEM;
6332
6333 mutex_lock(&graph_lock);
6334
6335 fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6336 lockdep_is_held(&graph_lock));
6337 fgd->type = GRAPH_FILTER_FUNCTION;
6338 fgd->seq_ops = &ftrace_graph_seq_ops;
6339
6340 ret = __ftrace_graph_open(inode, file, fgd);
6341 if (ret < 0)
6342 kfree(fgd);
6343
6344 mutex_unlock(&graph_lock);
6345 return ret;
6346 }
6347
6348 static int
ftrace_graph_notrace_open(struct inode * inode,struct file * file)6349 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6350 {
6351 struct ftrace_graph_data *fgd;
6352 int ret;
6353
6354 if (unlikely(ftrace_disabled))
6355 return -ENODEV;
6356
6357 fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6358 if (fgd == NULL)
6359 return -ENOMEM;
6360
6361 mutex_lock(&graph_lock);
6362
6363 fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6364 lockdep_is_held(&graph_lock));
6365 fgd->type = GRAPH_FILTER_NOTRACE;
6366 fgd->seq_ops = &ftrace_graph_seq_ops;
6367
6368 ret = __ftrace_graph_open(inode, file, fgd);
6369 if (ret < 0)
6370 kfree(fgd);
6371
6372 mutex_unlock(&graph_lock);
6373 return ret;
6374 }
6375
6376 static int
ftrace_graph_release(struct inode * inode,struct file * file)6377 ftrace_graph_release(struct inode *inode, struct file *file)
6378 {
6379 struct ftrace_graph_data *fgd;
6380 struct ftrace_hash *old_hash, *new_hash;
6381 struct trace_parser *parser;
6382 int ret = 0;
6383
6384 if (file->f_mode & FMODE_READ) {
6385 struct seq_file *m = file->private_data;
6386
6387 fgd = m->private;
6388 seq_release(inode, file);
6389 } else {
6390 fgd = file->private_data;
6391 }
6392
6393
6394 if (file->f_mode & FMODE_WRITE) {
6395
6396 parser = &fgd->parser;
6397
6398 if (trace_parser_loaded((parser))) {
6399 ret = ftrace_graph_set_hash(fgd->new_hash,
6400 parser->buffer);
6401 }
6402
6403 trace_parser_put(parser);
6404
6405 new_hash = __ftrace_hash_move(fgd->new_hash);
6406 if (!new_hash) {
6407 ret = -ENOMEM;
6408 goto out;
6409 }
6410
6411 mutex_lock(&graph_lock);
6412
6413 if (fgd->type == GRAPH_FILTER_FUNCTION) {
6414 old_hash = rcu_dereference_protected(ftrace_graph_hash,
6415 lockdep_is_held(&graph_lock));
6416 rcu_assign_pointer(ftrace_graph_hash, new_hash);
6417 } else {
6418 old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6419 lockdep_is_held(&graph_lock));
6420 rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6421 }
6422
6423 mutex_unlock(&graph_lock);
6424
6425 /*
6426 * We need to do a hard force of sched synchronization.
6427 * This is because we use preempt_disable() to do RCU, but
6428 * the function tracers can be called where RCU is not watching
6429 * (like before user_exit()). We can not rely on the RCU
6430 * infrastructure to do the synchronization, thus we must do it
6431 * ourselves.
6432 */
6433 if (old_hash != EMPTY_HASH)
6434 synchronize_rcu_tasks_rude();
6435
6436 free_ftrace_hash(old_hash);
6437 }
6438
6439 out:
6440 free_ftrace_hash(fgd->new_hash);
6441 kfree(fgd);
6442
6443 return ret;
6444 }
6445
6446 static int
ftrace_graph_set_hash(struct ftrace_hash * hash,char * buffer)6447 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6448 {
6449 struct ftrace_glob func_g;
6450 struct dyn_ftrace *rec;
6451 struct ftrace_page *pg;
6452 struct ftrace_func_entry *entry;
6453 int fail = 1;
6454 int not;
6455
6456 /* decode regex */
6457 func_g.type = filter_parse_regex(buffer, strlen(buffer),
6458 &func_g.search, ¬);
6459
6460 func_g.len = strlen(func_g.search);
6461
6462 mutex_lock(&ftrace_lock);
6463
6464 if (unlikely(ftrace_disabled)) {
6465 mutex_unlock(&ftrace_lock);
6466 return -ENODEV;
6467 }
6468
6469 do_for_each_ftrace_rec(pg, rec) {
6470
6471 if (rec->flags & FTRACE_FL_DISABLED)
6472 continue;
6473
6474 if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6475 entry = ftrace_lookup_ip(hash, rec->ip);
6476
6477 if (!not) {
6478 fail = 0;
6479
6480 if (entry)
6481 continue;
6482 if (add_hash_entry(hash, rec->ip) < 0)
6483 goto out;
6484 } else {
6485 if (entry) {
6486 free_hash_entry(hash, entry);
6487 fail = 0;
6488 }
6489 }
6490 }
6491 } while_for_each_ftrace_rec();
6492 out:
6493 mutex_unlock(&ftrace_lock);
6494
6495 if (fail)
6496 return -EINVAL;
6497
6498 return 0;
6499 }
6500
6501 static ssize_t
ftrace_graph_write(struct file * file,const char __user * ubuf,size_t cnt,loff_t * ppos)6502 ftrace_graph_write(struct file *file, const char __user *ubuf,
6503 size_t cnt, loff_t *ppos)
6504 {
6505 ssize_t read, ret = 0;
6506 struct ftrace_graph_data *fgd = file->private_data;
6507 struct trace_parser *parser;
6508
6509 if (!cnt)
6510 return 0;
6511
6512 /* Read mode uses seq functions */
6513 if (file->f_mode & FMODE_READ) {
6514 struct seq_file *m = file->private_data;
6515 fgd = m->private;
6516 }
6517
6518 parser = &fgd->parser;
6519
6520 read = trace_get_user(parser, ubuf, cnt, ppos);
6521
6522 if (read >= 0 && trace_parser_loaded(parser) &&
6523 !trace_parser_cont(parser)) {
6524
6525 ret = ftrace_graph_set_hash(fgd->new_hash,
6526 parser->buffer);
6527 trace_parser_clear(parser);
6528 }
6529
6530 if (!ret)
6531 ret = read;
6532
6533 return ret;
6534 }
6535
6536 static const struct file_operations ftrace_graph_fops = {
6537 .open = ftrace_graph_open,
6538 .read = seq_read,
6539 .write = ftrace_graph_write,
6540 .llseek = tracing_lseek,
6541 .release = ftrace_graph_release,
6542 };
6543
6544 static const struct file_operations ftrace_graph_notrace_fops = {
6545 .open = ftrace_graph_notrace_open,
6546 .read = seq_read,
6547 .write = ftrace_graph_write,
6548 .llseek = tracing_lseek,
6549 .release = ftrace_graph_release,
6550 };
6551 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6552
ftrace_create_filter_files(struct ftrace_ops * ops,struct dentry * parent)6553 void ftrace_create_filter_files(struct ftrace_ops *ops,
6554 struct dentry *parent)
6555 {
6556
6557 trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6558 ops, &ftrace_filter_fops);
6559
6560 trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6561 ops, &ftrace_notrace_fops);
6562 }
6563
6564 /*
6565 * The name "destroy_filter_files" is really a misnomer. Although
6566 * in the future, it may actually delete the files, but this is
6567 * really intended to make sure the ops passed in are disabled
6568 * and that when this function returns, the caller is free to
6569 * free the ops.
6570 *
6571 * The "destroy" name is only to match the "create" name that this
6572 * should be paired with.
6573 */
ftrace_destroy_filter_files(struct ftrace_ops * ops)6574 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6575 {
6576 mutex_lock(&ftrace_lock);
6577 if (ops->flags & FTRACE_OPS_FL_ENABLED)
6578 ftrace_shutdown(ops, 0);
6579 ops->flags |= FTRACE_OPS_FL_DELETED;
6580 ftrace_free_filter(ops);
6581 mutex_unlock(&ftrace_lock);
6582 }
6583
ftrace_init_dyn_tracefs(struct dentry * d_tracer)6584 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6585 {
6586
6587 trace_create_file("available_filter_functions", TRACE_MODE_READ,
6588 d_tracer, NULL, &ftrace_avail_fops);
6589
6590 trace_create_file("enabled_functions", TRACE_MODE_READ,
6591 d_tracer, NULL, &ftrace_enabled_fops);
6592
6593 ftrace_create_filter_files(&global_ops, d_tracer);
6594
6595 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
6596 trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6597 NULL,
6598 &ftrace_graph_fops);
6599 trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6600 NULL,
6601 &ftrace_graph_notrace_fops);
6602 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6603
6604 return 0;
6605 }
6606
ftrace_cmp_ips(const void * a,const void * b)6607 static int ftrace_cmp_ips(const void *a, const void *b)
6608 {
6609 const unsigned long *ipa = a;
6610 const unsigned long *ipb = b;
6611
6612 if (*ipa > *ipb)
6613 return 1;
6614 if (*ipa < *ipb)
6615 return -1;
6616 return 0;
6617 }
6618
6619 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
test_is_sorted(unsigned long * start,unsigned long count)6620 static void test_is_sorted(unsigned long *start, unsigned long count)
6621 {
6622 int i;
6623
6624 for (i = 1; i < count; i++) {
6625 if (WARN(start[i - 1] > start[i],
6626 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6627 (void *)start[i - 1], start[i - 1],
6628 (void *)start[i], start[i]))
6629 break;
6630 }
6631 if (i == count)
6632 pr_info("ftrace section at %px sorted properly\n", start);
6633 }
6634 #else
test_is_sorted(unsigned long * start,unsigned long count)6635 static void test_is_sorted(unsigned long *start, unsigned long count)
6636 {
6637 }
6638 #endif
6639
ftrace_process_locs(struct module * mod,unsigned long * start,unsigned long * end)6640 static int ftrace_process_locs(struct module *mod,
6641 unsigned long *start,
6642 unsigned long *end)
6643 {
6644 struct ftrace_page *start_pg;
6645 struct ftrace_page *pg;
6646 struct dyn_ftrace *rec;
6647 unsigned long count;
6648 unsigned long *p;
6649 unsigned long addr;
6650 unsigned long flags = 0; /* Shut up gcc */
6651 int ret = -ENOMEM;
6652
6653 count = end - start;
6654
6655 if (!count)
6656 return 0;
6657
6658 /*
6659 * Sorting mcount in vmlinux at build time depend on
6660 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6661 * modules can not be sorted at build time.
6662 */
6663 if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6664 sort(start, count, sizeof(*start),
6665 ftrace_cmp_ips, NULL);
6666 } else {
6667 test_is_sorted(start, count);
6668 }
6669
6670 start_pg = ftrace_allocate_pages(count);
6671 if (!start_pg)
6672 return -ENOMEM;
6673
6674 mutex_lock(&ftrace_lock);
6675
6676 /*
6677 * Core and each module needs their own pages, as
6678 * modules will free them when they are removed.
6679 * Force a new page to be allocated for modules.
6680 */
6681 if (!mod) {
6682 WARN_ON(ftrace_pages || ftrace_pages_start);
6683 /* First initialization */
6684 ftrace_pages = ftrace_pages_start = start_pg;
6685 } else {
6686 if (!ftrace_pages)
6687 goto out;
6688
6689 if (WARN_ON(ftrace_pages->next)) {
6690 /* Hmm, we have free pages? */
6691 while (ftrace_pages->next)
6692 ftrace_pages = ftrace_pages->next;
6693 }
6694
6695 ftrace_pages->next = start_pg;
6696 }
6697
6698 p = start;
6699 pg = start_pg;
6700 while (p < end) {
6701 unsigned long end_offset;
6702 addr = ftrace_call_adjust(*p++);
6703 /*
6704 * Some architecture linkers will pad between
6705 * the different mcount_loc sections of different
6706 * object files to satisfy alignments.
6707 * Skip any NULL pointers.
6708 */
6709 if (!addr)
6710 continue;
6711
6712 end_offset = (pg->index+1) * sizeof(pg->records[0]);
6713 if (end_offset > PAGE_SIZE << pg->order) {
6714 /* We should have allocated enough */
6715 if (WARN_ON(!pg->next))
6716 break;
6717 pg = pg->next;
6718 }
6719
6720 rec = &pg->records[pg->index++];
6721 rec->ip = addr;
6722 }
6723
6724 /* We should have used all pages */
6725 WARN_ON(pg->next);
6726
6727 /* Assign the last page to ftrace_pages */
6728 ftrace_pages = pg;
6729
6730 /*
6731 * We only need to disable interrupts on start up
6732 * because we are modifying code that an interrupt
6733 * may execute, and the modification is not atomic.
6734 * But for modules, nothing runs the code we modify
6735 * until we are finished with it, and there's no
6736 * reason to cause large interrupt latencies while we do it.
6737 */
6738 if (!mod)
6739 local_irq_save(flags);
6740 ftrace_update_code(mod, start_pg);
6741 if (!mod)
6742 local_irq_restore(flags);
6743 ret = 0;
6744 out:
6745 mutex_unlock(&ftrace_lock);
6746
6747 return ret;
6748 }
6749
6750 struct ftrace_mod_func {
6751 struct list_head list;
6752 char *name;
6753 unsigned long ip;
6754 unsigned int size;
6755 };
6756
6757 struct ftrace_mod_map {
6758 struct rcu_head rcu;
6759 struct list_head list;
6760 struct module *mod;
6761 unsigned long start_addr;
6762 unsigned long end_addr;
6763 struct list_head funcs;
6764 unsigned int num_funcs;
6765 };
6766
ftrace_get_trampoline_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)6767 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6768 unsigned long *value, char *type,
6769 char *name, char *module_name,
6770 int *exported)
6771 {
6772 struct ftrace_ops *op;
6773
6774 list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6775 if (!op->trampoline || symnum--)
6776 continue;
6777 *value = op->trampoline;
6778 *type = 't';
6779 strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6780 strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6781 *exported = 0;
6782 return 0;
6783 }
6784
6785 return -ERANGE;
6786 }
6787
6788 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6789 /*
6790 * Check if the current ops references the given ip.
6791 *
6792 * If the ops traces all functions, then it was already accounted for.
6793 * If the ops does not trace the current record function, skip it.
6794 * If the ops ignores the function via notrace filter, skip it.
6795 */
6796 static bool
ops_references_ip(struct ftrace_ops * ops,unsigned long ip)6797 ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6798 {
6799 /* If ops isn't enabled, ignore it */
6800 if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6801 return false;
6802
6803 /* If ops traces all then it includes this function */
6804 if (ops_traces_mod(ops))
6805 return true;
6806
6807 /* The function must be in the filter */
6808 if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6809 !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6810 return false;
6811
6812 /* If in notrace hash, we ignore it too */
6813 if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6814 return false;
6815
6816 return true;
6817 }
6818 #endif
6819
6820 #ifdef CONFIG_MODULES
6821
6822 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6823
6824 static LIST_HEAD(ftrace_mod_maps);
6825
referenced_filters(struct dyn_ftrace * rec)6826 static int referenced_filters(struct dyn_ftrace *rec)
6827 {
6828 struct ftrace_ops *ops;
6829 int cnt = 0;
6830
6831 for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6832 if (ops_references_ip(ops, rec->ip)) {
6833 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6834 continue;
6835 if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6836 continue;
6837 cnt++;
6838 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6839 rec->flags |= FTRACE_FL_REGS;
6840 if (cnt == 1 && ops->trampoline)
6841 rec->flags |= FTRACE_FL_TRAMP;
6842 else
6843 rec->flags &= ~FTRACE_FL_TRAMP;
6844 }
6845 }
6846
6847 return cnt;
6848 }
6849
6850 static void
clear_mod_from_hash(struct ftrace_page * pg,struct ftrace_hash * hash)6851 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6852 {
6853 struct ftrace_func_entry *entry;
6854 struct dyn_ftrace *rec;
6855 int i;
6856
6857 if (ftrace_hash_empty(hash))
6858 return;
6859
6860 for (i = 0; i < pg->index; i++) {
6861 rec = &pg->records[i];
6862 entry = __ftrace_lookup_ip(hash, rec->ip);
6863 /*
6864 * Do not allow this rec to match again.
6865 * Yeah, it may waste some memory, but will be removed
6866 * if/when the hash is modified again.
6867 */
6868 if (entry)
6869 entry->ip = 0;
6870 }
6871 }
6872
6873 /* Clear any records from hashes */
clear_mod_from_hashes(struct ftrace_page * pg)6874 static void clear_mod_from_hashes(struct ftrace_page *pg)
6875 {
6876 struct trace_array *tr;
6877
6878 mutex_lock(&trace_types_lock);
6879 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6880 if (!tr->ops || !tr->ops->func_hash)
6881 continue;
6882 mutex_lock(&tr->ops->func_hash->regex_lock);
6883 clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6884 clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6885 mutex_unlock(&tr->ops->func_hash->regex_lock);
6886 }
6887 mutex_unlock(&trace_types_lock);
6888 }
6889
ftrace_free_mod_map(struct rcu_head * rcu)6890 static void ftrace_free_mod_map(struct rcu_head *rcu)
6891 {
6892 struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6893 struct ftrace_mod_func *mod_func;
6894 struct ftrace_mod_func *n;
6895
6896 /* All the contents of mod_map are now not visible to readers */
6897 list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6898 kfree(mod_func->name);
6899 list_del(&mod_func->list);
6900 kfree(mod_func);
6901 }
6902
6903 kfree(mod_map);
6904 }
6905
ftrace_release_mod(struct module * mod)6906 void ftrace_release_mod(struct module *mod)
6907 {
6908 struct ftrace_mod_map *mod_map;
6909 struct ftrace_mod_map *n;
6910 struct dyn_ftrace *rec;
6911 struct ftrace_page **last_pg;
6912 struct ftrace_page *tmp_page = NULL;
6913 struct ftrace_page *pg;
6914
6915 mutex_lock(&ftrace_lock);
6916
6917 if (ftrace_disabled)
6918 goto out_unlock;
6919
6920 list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6921 if (mod_map->mod == mod) {
6922 list_del_rcu(&mod_map->list);
6923 call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6924 break;
6925 }
6926 }
6927
6928 /*
6929 * Each module has its own ftrace_pages, remove
6930 * them from the list.
6931 */
6932 last_pg = &ftrace_pages_start;
6933 for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6934 rec = &pg->records[0];
6935 if (within_module_core(rec->ip, mod) ||
6936 within_module_init(rec->ip, mod)) {
6937 /*
6938 * As core pages are first, the first
6939 * page should never be a module page.
6940 */
6941 if (WARN_ON(pg == ftrace_pages_start))
6942 goto out_unlock;
6943
6944 /* Check if we are deleting the last page */
6945 if (pg == ftrace_pages)
6946 ftrace_pages = next_to_ftrace_page(last_pg);
6947
6948 ftrace_update_tot_cnt -= pg->index;
6949 *last_pg = pg->next;
6950
6951 pg->next = tmp_page;
6952 tmp_page = pg;
6953 } else
6954 last_pg = &pg->next;
6955 }
6956 out_unlock:
6957 mutex_unlock(&ftrace_lock);
6958
6959 for (pg = tmp_page; pg; pg = tmp_page) {
6960
6961 /* Needs to be called outside of ftrace_lock */
6962 clear_mod_from_hashes(pg);
6963
6964 if (pg->records) {
6965 free_pages((unsigned long)pg->records, pg->order);
6966 ftrace_number_of_pages -= 1 << pg->order;
6967 }
6968 tmp_page = pg->next;
6969 kfree(pg);
6970 ftrace_number_of_groups--;
6971 }
6972 }
6973
ftrace_module_enable(struct module * mod)6974 void ftrace_module_enable(struct module *mod)
6975 {
6976 struct dyn_ftrace *rec;
6977 struct ftrace_page *pg;
6978
6979 mutex_lock(&ftrace_lock);
6980
6981 if (ftrace_disabled)
6982 goto out_unlock;
6983
6984 /*
6985 * If the tracing is enabled, go ahead and enable the record.
6986 *
6987 * The reason not to enable the record immediately is the
6988 * inherent check of ftrace_make_nop/ftrace_make_call for
6989 * correct previous instructions. Making first the NOP
6990 * conversion puts the module to the correct state, thus
6991 * passing the ftrace_make_call check.
6992 *
6993 * We also delay this to after the module code already set the
6994 * text to read-only, as we now need to set it back to read-write
6995 * so that we can modify the text.
6996 */
6997 if (ftrace_start_up)
6998 ftrace_arch_code_modify_prepare();
6999
7000 do_for_each_ftrace_rec(pg, rec) {
7001 int cnt;
7002 /*
7003 * do_for_each_ftrace_rec() is a double loop.
7004 * module text shares the pg. If a record is
7005 * not part of this module, then skip this pg,
7006 * which the "break" will do.
7007 */
7008 if (!within_module_core(rec->ip, mod) &&
7009 !within_module_init(rec->ip, mod))
7010 break;
7011
7012 /* Weak functions should still be ignored */
7013 if (!test_for_valid_rec(rec)) {
7014 /* Clear all other flags. Should not be enabled anyway */
7015 rec->flags = FTRACE_FL_DISABLED;
7016 continue;
7017 }
7018
7019 cnt = 0;
7020
7021 /*
7022 * When adding a module, we need to check if tracers are
7023 * currently enabled and if they are, and can trace this record,
7024 * we need to enable the module functions as well as update the
7025 * reference counts for those function records.
7026 */
7027 if (ftrace_start_up)
7028 cnt += referenced_filters(rec);
7029
7030 rec->flags &= ~FTRACE_FL_DISABLED;
7031 rec->flags += cnt;
7032
7033 if (ftrace_start_up && cnt) {
7034 int failed = __ftrace_replace_code(rec, 1);
7035 if (failed) {
7036 ftrace_bug(failed, rec);
7037 goto out_loop;
7038 }
7039 }
7040
7041 } while_for_each_ftrace_rec();
7042
7043 out_loop:
7044 if (ftrace_start_up)
7045 ftrace_arch_code_modify_post_process();
7046
7047 out_unlock:
7048 mutex_unlock(&ftrace_lock);
7049
7050 process_cached_mods(mod->name);
7051 }
7052
ftrace_module_init(struct module * mod)7053 void ftrace_module_init(struct module *mod)
7054 {
7055 int ret;
7056
7057 if (ftrace_disabled || !mod->num_ftrace_callsites)
7058 return;
7059
7060 ret = ftrace_process_locs(mod, mod->ftrace_callsites,
7061 mod->ftrace_callsites + mod->num_ftrace_callsites);
7062 if (ret)
7063 pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
7064 mod->name);
7065 }
7066
save_ftrace_mod_rec(struct ftrace_mod_map * mod_map,struct dyn_ftrace * rec)7067 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7068 struct dyn_ftrace *rec)
7069 {
7070 struct ftrace_mod_func *mod_func;
7071 unsigned long symsize;
7072 unsigned long offset;
7073 char str[KSYM_SYMBOL_LEN];
7074 char *modname;
7075 const char *ret;
7076
7077 ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
7078 if (!ret)
7079 return;
7080
7081 mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
7082 if (!mod_func)
7083 return;
7084
7085 mod_func->name = kstrdup(str, GFP_KERNEL);
7086 if (!mod_func->name) {
7087 kfree(mod_func);
7088 return;
7089 }
7090
7091 mod_func->ip = rec->ip - offset;
7092 mod_func->size = symsize;
7093
7094 mod_map->num_funcs++;
7095
7096 list_add_rcu(&mod_func->list, &mod_map->funcs);
7097 }
7098
7099 static struct ftrace_mod_map *
allocate_ftrace_mod_map(struct module * mod,unsigned long start,unsigned long end)7100 allocate_ftrace_mod_map(struct module *mod,
7101 unsigned long start, unsigned long end)
7102 {
7103 struct ftrace_mod_map *mod_map;
7104
7105 mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
7106 if (!mod_map)
7107 return NULL;
7108
7109 mod_map->mod = mod;
7110 mod_map->start_addr = start;
7111 mod_map->end_addr = end;
7112 mod_map->num_funcs = 0;
7113
7114 INIT_LIST_HEAD_RCU(&mod_map->funcs);
7115
7116 list_add_rcu(&mod_map->list, &ftrace_mod_maps);
7117
7118 return mod_map;
7119 }
7120
7121 static const char *
ftrace_func_address_lookup(struct ftrace_mod_map * mod_map,unsigned long addr,unsigned long * size,unsigned long * off,char * sym)7122 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
7123 unsigned long addr, unsigned long *size,
7124 unsigned long *off, char *sym)
7125 {
7126 struct ftrace_mod_func *found_func = NULL;
7127 struct ftrace_mod_func *mod_func;
7128
7129 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7130 if (addr >= mod_func->ip &&
7131 addr < mod_func->ip + mod_func->size) {
7132 found_func = mod_func;
7133 break;
7134 }
7135 }
7136
7137 if (found_func) {
7138 if (size)
7139 *size = found_func->size;
7140 if (off)
7141 *off = addr - found_func->ip;
7142 if (sym)
7143 strlcpy(sym, found_func->name, KSYM_NAME_LEN);
7144
7145 return found_func->name;
7146 }
7147
7148 return NULL;
7149 }
7150
7151 const char *
ftrace_mod_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char ** modname,char * sym)7152 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7153 unsigned long *off, char **modname, char *sym)
7154 {
7155 struct ftrace_mod_map *mod_map;
7156 const char *ret = NULL;
7157
7158 /* mod_map is freed via call_rcu() */
7159 preempt_disable();
7160 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7161 ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7162 if (ret) {
7163 if (modname)
7164 *modname = mod_map->mod->name;
7165 break;
7166 }
7167 }
7168 preempt_enable();
7169
7170 return ret;
7171 }
7172
ftrace_mod_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)7173 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7174 char *type, char *name,
7175 char *module_name, int *exported)
7176 {
7177 struct ftrace_mod_map *mod_map;
7178 struct ftrace_mod_func *mod_func;
7179 int ret;
7180
7181 preempt_disable();
7182 list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7183
7184 if (symnum >= mod_map->num_funcs) {
7185 symnum -= mod_map->num_funcs;
7186 continue;
7187 }
7188
7189 list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7190 if (symnum > 1) {
7191 symnum--;
7192 continue;
7193 }
7194
7195 *value = mod_func->ip;
7196 *type = 'T';
7197 strlcpy(name, mod_func->name, KSYM_NAME_LEN);
7198 strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7199 *exported = 1;
7200 preempt_enable();
7201 return 0;
7202 }
7203 WARN_ON(1);
7204 break;
7205 }
7206 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7207 module_name, exported);
7208 preempt_enable();
7209 return ret;
7210 }
7211
7212 #else
save_ftrace_mod_rec(struct ftrace_mod_map * mod_map,struct dyn_ftrace * rec)7213 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7214 struct dyn_ftrace *rec) { }
7215 static inline struct ftrace_mod_map *
allocate_ftrace_mod_map(struct module * mod,unsigned long start,unsigned long end)7216 allocate_ftrace_mod_map(struct module *mod,
7217 unsigned long start, unsigned long end)
7218 {
7219 return NULL;
7220 }
ftrace_mod_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)7221 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7222 char *type, char *name, char *module_name,
7223 int *exported)
7224 {
7225 int ret;
7226
7227 preempt_disable();
7228 ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7229 module_name, exported);
7230 preempt_enable();
7231 return ret;
7232 }
7233 #endif /* CONFIG_MODULES */
7234
7235 struct ftrace_init_func {
7236 struct list_head list;
7237 unsigned long ip;
7238 };
7239
7240 /* Clear any init ips from hashes */
7241 static void
clear_func_from_hash(struct ftrace_init_func * func,struct ftrace_hash * hash)7242 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7243 {
7244 struct ftrace_func_entry *entry;
7245
7246 entry = ftrace_lookup_ip(hash, func->ip);
7247 /*
7248 * Do not allow this rec to match again.
7249 * Yeah, it may waste some memory, but will be removed
7250 * if/when the hash is modified again.
7251 */
7252 if (entry)
7253 entry->ip = 0;
7254 }
7255
7256 static void
clear_func_from_hashes(struct ftrace_init_func * func)7257 clear_func_from_hashes(struct ftrace_init_func *func)
7258 {
7259 struct trace_array *tr;
7260
7261 mutex_lock(&trace_types_lock);
7262 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7263 if (!tr->ops || !tr->ops->func_hash)
7264 continue;
7265 mutex_lock(&tr->ops->func_hash->regex_lock);
7266 clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7267 clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7268 mutex_unlock(&tr->ops->func_hash->regex_lock);
7269 }
7270 mutex_unlock(&trace_types_lock);
7271 }
7272
add_to_clear_hash_list(struct list_head * clear_list,struct dyn_ftrace * rec)7273 static void add_to_clear_hash_list(struct list_head *clear_list,
7274 struct dyn_ftrace *rec)
7275 {
7276 struct ftrace_init_func *func;
7277
7278 func = kmalloc(sizeof(*func), GFP_KERNEL);
7279 if (!func) {
7280 MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7281 return;
7282 }
7283
7284 func->ip = rec->ip;
7285 list_add(&func->list, clear_list);
7286 }
7287
ftrace_free_mem(struct module * mod,void * start_ptr,void * end_ptr)7288 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7289 {
7290 unsigned long start = (unsigned long)(start_ptr);
7291 unsigned long end = (unsigned long)(end_ptr);
7292 struct ftrace_page **last_pg = &ftrace_pages_start;
7293 struct ftrace_page *pg;
7294 struct dyn_ftrace *rec;
7295 struct dyn_ftrace key;
7296 struct ftrace_mod_map *mod_map = NULL;
7297 struct ftrace_init_func *func, *func_next;
7298 struct list_head clear_hash;
7299
7300 INIT_LIST_HEAD(&clear_hash);
7301
7302 key.ip = start;
7303 key.flags = end; /* overload flags, as it is unsigned long */
7304
7305 mutex_lock(&ftrace_lock);
7306
7307 /*
7308 * If we are freeing module init memory, then check if
7309 * any tracer is active. If so, we need to save a mapping of
7310 * the module functions being freed with the address.
7311 */
7312 if (mod && ftrace_ops_list != &ftrace_list_end)
7313 mod_map = allocate_ftrace_mod_map(mod, start, end);
7314
7315 for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7316 if (end < pg->records[0].ip ||
7317 start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7318 continue;
7319 again:
7320 rec = bsearch(&key, pg->records, pg->index,
7321 sizeof(struct dyn_ftrace),
7322 ftrace_cmp_recs);
7323 if (!rec)
7324 continue;
7325
7326 /* rec will be cleared from hashes after ftrace_lock unlock */
7327 add_to_clear_hash_list(&clear_hash, rec);
7328
7329 if (mod_map)
7330 save_ftrace_mod_rec(mod_map, rec);
7331
7332 pg->index--;
7333 ftrace_update_tot_cnt--;
7334 if (!pg->index) {
7335 *last_pg = pg->next;
7336 if (pg->records) {
7337 free_pages((unsigned long)pg->records, pg->order);
7338 ftrace_number_of_pages -= 1 << pg->order;
7339 }
7340 ftrace_number_of_groups--;
7341 kfree(pg);
7342 pg = container_of(last_pg, struct ftrace_page, next);
7343 if (!(*last_pg))
7344 ftrace_pages = pg;
7345 continue;
7346 }
7347 memmove(rec, rec + 1,
7348 (pg->index - (rec - pg->records)) * sizeof(*rec));
7349 /* More than one function may be in this block */
7350 goto again;
7351 }
7352 mutex_unlock(&ftrace_lock);
7353
7354 list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7355 clear_func_from_hashes(func);
7356 kfree(func);
7357 }
7358 }
7359
ftrace_free_init_mem(void)7360 void __init ftrace_free_init_mem(void)
7361 {
7362 void *start = (void *)(&__init_begin);
7363 void *end = (void *)(&__init_end);
7364
7365 ftrace_boot_snapshot();
7366
7367 ftrace_free_mem(NULL, start, end);
7368 }
7369
ftrace_dyn_arch_init(void)7370 int __init __weak ftrace_dyn_arch_init(void)
7371 {
7372 return 0;
7373 }
7374
ftrace_init(void)7375 void __init ftrace_init(void)
7376 {
7377 extern unsigned long __start_mcount_loc[];
7378 extern unsigned long __stop_mcount_loc[];
7379 unsigned long count, flags;
7380 int ret;
7381
7382 local_irq_save(flags);
7383 ret = ftrace_dyn_arch_init();
7384 local_irq_restore(flags);
7385 if (ret)
7386 goto failed;
7387
7388 count = __stop_mcount_loc - __start_mcount_loc;
7389 if (!count) {
7390 pr_info("ftrace: No functions to be traced?\n");
7391 goto failed;
7392 }
7393
7394 pr_info("ftrace: allocating %ld entries in %ld pages\n",
7395 count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7396
7397 ret = ftrace_process_locs(NULL,
7398 __start_mcount_loc,
7399 __stop_mcount_loc);
7400 if (ret) {
7401 pr_warn("ftrace: failed to allocate entries for functions\n");
7402 goto failed;
7403 }
7404
7405 pr_info("ftrace: allocated %ld pages with %ld groups\n",
7406 ftrace_number_of_pages, ftrace_number_of_groups);
7407
7408 last_ftrace_enabled = ftrace_enabled = 1;
7409
7410 set_ftrace_early_filters();
7411
7412 return;
7413 failed:
7414 ftrace_disabled = 1;
7415 }
7416
7417 /* Do nothing if arch does not support this */
arch_ftrace_update_trampoline(struct ftrace_ops * ops)7418 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7419 {
7420 }
7421
ftrace_update_trampoline(struct ftrace_ops * ops)7422 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7423 {
7424 unsigned long trampoline = ops->trampoline;
7425
7426 arch_ftrace_update_trampoline(ops);
7427 if (ops->trampoline && ops->trampoline != trampoline &&
7428 (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7429 /* Add to kallsyms before the perf events */
7430 ftrace_add_trampoline_to_kallsyms(ops);
7431 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7432 ops->trampoline, ops->trampoline_size, false,
7433 FTRACE_TRAMPOLINE_SYM);
7434 /*
7435 * Record the perf text poke event after the ksymbol register
7436 * event.
7437 */
7438 perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7439 (void *)ops->trampoline,
7440 ops->trampoline_size);
7441 }
7442 }
7443
ftrace_init_trace_array(struct trace_array * tr)7444 void ftrace_init_trace_array(struct trace_array *tr)
7445 {
7446 INIT_LIST_HEAD(&tr->func_probes);
7447 INIT_LIST_HEAD(&tr->mod_trace);
7448 INIT_LIST_HEAD(&tr->mod_notrace);
7449 }
7450 #else
7451
7452 struct ftrace_ops global_ops = {
7453 .func = ftrace_stub,
7454 .flags = FTRACE_OPS_FL_INITIALIZED |
7455 FTRACE_OPS_FL_PID,
7456 };
7457
ftrace_nodyn_init(void)7458 static int __init ftrace_nodyn_init(void)
7459 {
7460 ftrace_enabled = 1;
7461 return 0;
7462 }
7463 core_initcall(ftrace_nodyn_init);
7464
ftrace_init_dyn_tracefs(struct dentry * d_tracer)7465 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
ftrace_startup_all(int command)7466 static inline void ftrace_startup_all(int command) { }
7467
ftrace_update_trampoline(struct ftrace_ops * ops)7468 static void ftrace_update_trampoline(struct ftrace_ops *ops)
7469 {
7470 }
7471
7472 #endif /* CONFIG_DYNAMIC_FTRACE */
7473
ftrace_init_global_array_ops(struct trace_array * tr)7474 __init void ftrace_init_global_array_ops(struct trace_array *tr)
7475 {
7476 tr->ops = &global_ops;
7477 tr->ops->private = tr;
7478 ftrace_init_trace_array(tr);
7479 }
7480
ftrace_init_array_ops(struct trace_array * tr,ftrace_func_t func)7481 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7482 {
7483 /* If we filter on pids, update to use the pid function */
7484 if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7485 if (WARN_ON(tr->ops->func != ftrace_stub))
7486 printk("ftrace ops had %pS for function\n",
7487 tr->ops->func);
7488 }
7489 tr->ops->func = func;
7490 tr->ops->private = tr;
7491 }
7492
ftrace_reset_array_ops(struct trace_array * tr)7493 void ftrace_reset_array_ops(struct trace_array *tr)
7494 {
7495 tr->ops->func = ftrace_stub;
7496 }
7497
7498 static nokprobe_inline void
__ftrace_ops_list_func(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * ignored,struct ftrace_regs * fregs)7499 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7500 struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7501 {
7502 struct pt_regs *regs = ftrace_get_regs(fregs);
7503 struct ftrace_ops *op;
7504 int bit;
7505
7506 /*
7507 * The ftrace_test_and_set_recursion() will disable preemption,
7508 * which is required since some of the ops may be dynamically
7509 * allocated, they must be freed after a synchronize_rcu().
7510 */
7511 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7512 if (bit < 0)
7513 return;
7514
7515 do_for_each_ftrace_op(op, ftrace_ops_list) {
7516 /* Stub functions don't need to be called nor tested */
7517 if (op->flags & FTRACE_OPS_FL_STUB)
7518 continue;
7519 /*
7520 * Check the following for each ops before calling their func:
7521 * if RCU flag is set, then rcu_is_watching() must be true
7522 * if PER_CPU is set, then ftrace_function_local_disable()
7523 * must be false
7524 * Otherwise test if the ip matches the ops filter
7525 *
7526 * If any of the above fails then the op->func() is not executed.
7527 */
7528 if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7529 ftrace_ops_test(op, ip, regs)) {
7530 if (FTRACE_WARN_ON(!op->func)) {
7531 pr_warn("op=%p %pS\n", op, op);
7532 goto out;
7533 }
7534 op->func(ip, parent_ip, op, fregs);
7535 }
7536 } while_for_each_ftrace_op(op);
7537 out:
7538 trace_clear_recursion(bit);
7539 }
7540
7541 /*
7542 * Some archs only support passing ip and parent_ip. Even though
7543 * the list function ignores the op parameter, we do not want any
7544 * C side effects, where a function is called without the caller
7545 * sending a third parameter.
7546 * Archs are to support both the regs and ftrace_ops at the same time.
7547 * If they support ftrace_ops, it is assumed they support regs.
7548 * If call backs want to use regs, they must either check for regs
7549 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7550 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7551 * An architecture can pass partial regs with ftrace_ops and still
7552 * set the ARCH_SUPPORTS_FTRACE_OPS.
7553 *
7554 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7555 * arch_ftrace_ops_list_func.
7556 */
7557 #if ARCH_SUPPORTS_FTRACE_OPS
arch_ftrace_ops_list_func(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)7558 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7559 struct ftrace_ops *op, struct ftrace_regs *fregs)
7560 {
7561 __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7562 }
7563 #else
arch_ftrace_ops_list_func(unsigned long ip,unsigned long parent_ip)7564 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7565 {
7566 __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7567 }
7568 #endif
7569 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7570
7571 /*
7572 * If there's only one function registered but it does not support
7573 * recursion, needs RCU protection and/or requires per cpu handling, then
7574 * this function will be called by the mcount trampoline.
7575 */
ftrace_ops_assist_func(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)7576 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7577 struct ftrace_ops *op, struct ftrace_regs *fregs)
7578 {
7579 int bit;
7580
7581 bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7582 if (bit < 0)
7583 return;
7584
7585 if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7586 op->func(ip, parent_ip, op, fregs);
7587
7588 trace_clear_recursion(bit);
7589 }
7590 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7591
7592 /**
7593 * ftrace_ops_get_func - get the function a trampoline should call
7594 * @ops: the ops to get the function for
7595 *
7596 * Normally the mcount trampoline will call the ops->func, but there
7597 * are times that it should not. For example, if the ops does not
7598 * have its own recursion protection, then it should call the
7599 * ftrace_ops_assist_func() instead.
7600 *
7601 * Returns the function that the trampoline should call for @ops.
7602 */
ftrace_ops_get_func(struct ftrace_ops * ops)7603 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7604 {
7605 /*
7606 * If the function does not handle recursion or needs to be RCU safe,
7607 * then we need to call the assist handler.
7608 */
7609 if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7610 FTRACE_OPS_FL_RCU))
7611 return ftrace_ops_assist_func;
7612
7613 return ops->func;
7614 }
7615
7616 static void
ftrace_filter_pid_sched_switch_probe(void * data,bool preempt,struct task_struct * prev,struct task_struct * next,unsigned int prev_state)7617 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7618 struct task_struct *prev,
7619 struct task_struct *next,
7620 unsigned int prev_state)
7621 {
7622 struct trace_array *tr = data;
7623 struct trace_pid_list *pid_list;
7624 struct trace_pid_list *no_pid_list;
7625
7626 pid_list = rcu_dereference_sched(tr->function_pids);
7627 no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7628
7629 if (trace_ignore_this_task(pid_list, no_pid_list, next))
7630 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7631 FTRACE_PID_IGNORE);
7632 else
7633 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7634 next->pid);
7635 }
7636
7637 static void
ftrace_pid_follow_sched_process_fork(void * data,struct task_struct * self,struct task_struct * task)7638 ftrace_pid_follow_sched_process_fork(void *data,
7639 struct task_struct *self,
7640 struct task_struct *task)
7641 {
7642 struct trace_pid_list *pid_list;
7643 struct trace_array *tr = data;
7644
7645 pid_list = rcu_dereference_sched(tr->function_pids);
7646 trace_filter_add_remove_task(pid_list, self, task);
7647
7648 pid_list = rcu_dereference_sched(tr->function_no_pids);
7649 trace_filter_add_remove_task(pid_list, self, task);
7650 }
7651
7652 static void
ftrace_pid_follow_sched_process_exit(void * data,struct task_struct * task)7653 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7654 {
7655 struct trace_pid_list *pid_list;
7656 struct trace_array *tr = data;
7657
7658 pid_list = rcu_dereference_sched(tr->function_pids);
7659 trace_filter_add_remove_task(pid_list, NULL, task);
7660
7661 pid_list = rcu_dereference_sched(tr->function_no_pids);
7662 trace_filter_add_remove_task(pid_list, NULL, task);
7663 }
7664
ftrace_pid_follow_fork(struct trace_array * tr,bool enable)7665 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7666 {
7667 if (enable) {
7668 register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7669 tr);
7670 register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7671 tr);
7672 } else {
7673 unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7674 tr);
7675 unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7676 tr);
7677 }
7678 }
7679
clear_ftrace_pids(struct trace_array * tr,int type)7680 static void clear_ftrace_pids(struct trace_array *tr, int type)
7681 {
7682 struct trace_pid_list *pid_list;
7683 struct trace_pid_list *no_pid_list;
7684 int cpu;
7685
7686 pid_list = rcu_dereference_protected(tr->function_pids,
7687 lockdep_is_held(&ftrace_lock));
7688 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7689 lockdep_is_held(&ftrace_lock));
7690
7691 /* Make sure there's something to do */
7692 if (!pid_type_enabled(type, pid_list, no_pid_list))
7693 return;
7694
7695 /* See if the pids still need to be checked after this */
7696 if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7697 unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7698 for_each_possible_cpu(cpu)
7699 per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7700 }
7701
7702 if (type & TRACE_PIDS)
7703 rcu_assign_pointer(tr->function_pids, NULL);
7704
7705 if (type & TRACE_NO_PIDS)
7706 rcu_assign_pointer(tr->function_no_pids, NULL);
7707
7708 /* Wait till all users are no longer using pid filtering */
7709 synchronize_rcu();
7710
7711 if ((type & TRACE_PIDS) && pid_list)
7712 trace_pid_list_free(pid_list);
7713
7714 if ((type & TRACE_NO_PIDS) && no_pid_list)
7715 trace_pid_list_free(no_pid_list);
7716 }
7717
ftrace_clear_pids(struct trace_array * tr)7718 void ftrace_clear_pids(struct trace_array *tr)
7719 {
7720 mutex_lock(&ftrace_lock);
7721
7722 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7723
7724 mutex_unlock(&ftrace_lock);
7725 }
7726
ftrace_pid_reset(struct trace_array * tr,int type)7727 static void ftrace_pid_reset(struct trace_array *tr, int type)
7728 {
7729 mutex_lock(&ftrace_lock);
7730 clear_ftrace_pids(tr, type);
7731
7732 ftrace_update_pid_func();
7733 ftrace_startup_all(0);
7734
7735 mutex_unlock(&ftrace_lock);
7736 }
7737
7738 /* Greater than any max PID */
7739 #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
7740
fpid_start(struct seq_file * m,loff_t * pos)7741 static void *fpid_start(struct seq_file *m, loff_t *pos)
7742 __acquires(RCU)
7743 {
7744 struct trace_pid_list *pid_list;
7745 struct trace_array *tr = m->private;
7746
7747 mutex_lock(&ftrace_lock);
7748 rcu_read_lock_sched();
7749
7750 pid_list = rcu_dereference_sched(tr->function_pids);
7751
7752 if (!pid_list)
7753 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7754
7755 return trace_pid_start(pid_list, pos);
7756 }
7757
fpid_next(struct seq_file * m,void * v,loff_t * pos)7758 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7759 {
7760 struct trace_array *tr = m->private;
7761 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7762
7763 if (v == FTRACE_NO_PIDS) {
7764 (*pos)++;
7765 return NULL;
7766 }
7767 return trace_pid_next(pid_list, v, pos);
7768 }
7769
fpid_stop(struct seq_file * m,void * p)7770 static void fpid_stop(struct seq_file *m, void *p)
7771 __releases(RCU)
7772 {
7773 rcu_read_unlock_sched();
7774 mutex_unlock(&ftrace_lock);
7775 }
7776
fpid_show(struct seq_file * m,void * v)7777 static int fpid_show(struct seq_file *m, void *v)
7778 {
7779 if (v == FTRACE_NO_PIDS) {
7780 seq_puts(m, "no pid\n");
7781 return 0;
7782 }
7783
7784 return trace_pid_show(m, v);
7785 }
7786
7787 static const struct seq_operations ftrace_pid_sops = {
7788 .start = fpid_start,
7789 .next = fpid_next,
7790 .stop = fpid_stop,
7791 .show = fpid_show,
7792 };
7793
fnpid_start(struct seq_file * m,loff_t * pos)7794 static void *fnpid_start(struct seq_file *m, loff_t *pos)
7795 __acquires(RCU)
7796 {
7797 struct trace_pid_list *pid_list;
7798 struct trace_array *tr = m->private;
7799
7800 mutex_lock(&ftrace_lock);
7801 rcu_read_lock_sched();
7802
7803 pid_list = rcu_dereference_sched(tr->function_no_pids);
7804
7805 if (!pid_list)
7806 return !(*pos) ? FTRACE_NO_PIDS : NULL;
7807
7808 return trace_pid_start(pid_list, pos);
7809 }
7810
fnpid_next(struct seq_file * m,void * v,loff_t * pos)7811 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7812 {
7813 struct trace_array *tr = m->private;
7814 struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7815
7816 if (v == FTRACE_NO_PIDS) {
7817 (*pos)++;
7818 return NULL;
7819 }
7820 return trace_pid_next(pid_list, v, pos);
7821 }
7822
7823 static const struct seq_operations ftrace_no_pid_sops = {
7824 .start = fnpid_start,
7825 .next = fnpid_next,
7826 .stop = fpid_stop,
7827 .show = fpid_show,
7828 };
7829
pid_open(struct inode * inode,struct file * file,int type)7830 static int pid_open(struct inode *inode, struct file *file, int type)
7831 {
7832 const struct seq_operations *seq_ops;
7833 struct trace_array *tr = inode->i_private;
7834 struct seq_file *m;
7835 int ret = 0;
7836
7837 ret = tracing_check_open_get_tr(tr);
7838 if (ret)
7839 return ret;
7840
7841 if ((file->f_mode & FMODE_WRITE) &&
7842 (file->f_flags & O_TRUNC))
7843 ftrace_pid_reset(tr, type);
7844
7845 switch (type) {
7846 case TRACE_PIDS:
7847 seq_ops = &ftrace_pid_sops;
7848 break;
7849 case TRACE_NO_PIDS:
7850 seq_ops = &ftrace_no_pid_sops;
7851 break;
7852 default:
7853 trace_array_put(tr);
7854 WARN_ON_ONCE(1);
7855 return -EINVAL;
7856 }
7857
7858 ret = seq_open(file, seq_ops);
7859 if (ret < 0) {
7860 trace_array_put(tr);
7861 } else {
7862 m = file->private_data;
7863 /* copy tr over to seq ops */
7864 m->private = tr;
7865 }
7866
7867 return ret;
7868 }
7869
7870 static int
ftrace_pid_open(struct inode * inode,struct file * file)7871 ftrace_pid_open(struct inode *inode, struct file *file)
7872 {
7873 return pid_open(inode, file, TRACE_PIDS);
7874 }
7875
7876 static int
ftrace_no_pid_open(struct inode * inode,struct file * file)7877 ftrace_no_pid_open(struct inode *inode, struct file *file)
7878 {
7879 return pid_open(inode, file, TRACE_NO_PIDS);
7880 }
7881
ignore_task_cpu(void * data)7882 static void ignore_task_cpu(void *data)
7883 {
7884 struct trace_array *tr = data;
7885 struct trace_pid_list *pid_list;
7886 struct trace_pid_list *no_pid_list;
7887
7888 /*
7889 * This function is called by on_each_cpu() while the
7890 * event_mutex is held.
7891 */
7892 pid_list = rcu_dereference_protected(tr->function_pids,
7893 mutex_is_locked(&ftrace_lock));
7894 no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7895 mutex_is_locked(&ftrace_lock));
7896
7897 if (trace_ignore_this_task(pid_list, no_pid_list, current))
7898 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7899 FTRACE_PID_IGNORE);
7900 else
7901 this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7902 current->pid);
7903 }
7904
7905 static ssize_t
pid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos,int type)7906 pid_write(struct file *filp, const char __user *ubuf,
7907 size_t cnt, loff_t *ppos, int type)
7908 {
7909 struct seq_file *m = filp->private_data;
7910 struct trace_array *tr = m->private;
7911 struct trace_pid_list *filtered_pids;
7912 struct trace_pid_list *other_pids;
7913 struct trace_pid_list *pid_list;
7914 ssize_t ret;
7915
7916 if (!cnt)
7917 return 0;
7918
7919 mutex_lock(&ftrace_lock);
7920
7921 switch (type) {
7922 case TRACE_PIDS:
7923 filtered_pids = rcu_dereference_protected(tr->function_pids,
7924 lockdep_is_held(&ftrace_lock));
7925 other_pids = rcu_dereference_protected(tr->function_no_pids,
7926 lockdep_is_held(&ftrace_lock));
7927 break;
7928 case TRACE_NO_PIDS:
7929 filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7930 lockdep_is_held(&ftrace_lock));
7931 other_pids = rcu_dereference_protected(tr->function_pids,
7932 lockdep_is_held(&ftrace_lock));
7933 break;
7934 default:
7935 ret = -EINVAL;
7936 WARN_ON_ONCE(1);
7937 goto out;
7938 }
7939
7940 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7941 if (ret < 0)
7942 goto out;
7943
7944 switch (type) {
7945 case TRACE_PIDS:
7946 rcu_assign_pointer(tr->function_pids, pid_list);
7947 break;
7948 case TRACE_NO_PIDS:
7949 rcu_assign_pointer(tr->function_no_pids, pid_list);
7950 break;
7951 }
7952
7953
7954 if (filtered_pids) {
7955 synchronize_rcu();
7956 trace_pid_list_free(filtered_pids);
7957 } else if (pid_list && !other_pids) {
7958 /* Register a probe to set whether to ignore the tracing of a task */
7959 register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7960 }
7961
7962 /*
7963 * Ignoring of pids is done at task switch. But we have to
7964 * check for those tasks that are currently running.
7965 * Always do this in case a pid was appended or removed.
7966 */
7967 on_each_cpu(ignore_task_cpu, tr, 1);
7968
7969 ftrace_update_pid_func();
7970 ftrace_startup_all(0);
7971 out:
7972 mutex_unlock(&ftrace_lock);
7973
7974 if (ret > 0)
7975 *ppos += ret;
7976
7977 return ret;
7978 }
7979
7980 static ssize_t
ftrace_pid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)7981 ftrace_pid_write(struct file *filp, const char __user *ubuf,
7982 size_t cnt, loff_t *ppos)
7983 {
7984 return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7985 }
7986
7987 static ssize_t
ftrace_no_pid_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)7988 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7989 size_t cnt, loff_t *ppos)
7990 {
7991 return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7992 }
7993
7994 static int
ftrace_pid_release(struct inode * inode,struct file * file)7995 ftrace_pid_release(struct inode *inode, struct file *file)
7996 {
7997 struct trace_array *tr = inode->i_private;
7998
7999 trace_array_put(tr);
8000
8001 return seq_release(inode, file);
8002 }
8003
8004 static const struct file_operations ftrace_pid_fops = {
8005 .open = ftrace_pid_open,
8006 .write = ftrace_pid_write,
8007 .read = seq_read,
8008 .llseek = tracing_lseek,
8009 .release = ftrace_pid_release,
8010 };
8011
8012 static const struct file_operations ftrace_no_pid_fops = {
8013 .open = ftrace_no_pid_open,
8014 .write = ftrace_no_pid_write,
8015 .read = seq_read,
8016 .llseek = tracing_lseek,
8017 .release = ftrace_pid_release,
8018 };
8019
ftrace_init_tracefs(struct trace_array * tr,struct dentry * d_tracer)8020 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8021 {
8022 trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
8023 tr, &ftrace_pid_fops);
8024 trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
8025 d_tracer, tr, &ftrace_no_pid_fops);
8026 }
8027
ftrace_init_tracefs_toplevel(struct trace_array * tr,struct dentry * d_tracer)8028 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
8029 struct dentry *d_tracer)
8030 {
8031 /* Only the top level directory has the dyn_tracefs and profile */
8032 WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
8033
8034 ftrace_init_dyn_tracefs(d_tracer);
8035 ftrace_profile_tracefs(d_tracer);
8036 }
8037
8038 /**
8039 * ftrace_kill - kill ftrace
8040 *
8041 * This function should be used by panic code. It stops ftrace
8042 * but in a not so nice way. If you need to simply kill ftrace
8043 * from a non-atomic section, use ftrace_kill.
8044 */
ftrace_kill(void)8045 void ftrace_kill(void)
8046 {
8047 ftrace_disabled = 1;
8048 ftrace_enabled = 0;
8049 ftrace_trace_function = ftrace_stub;
8050 }
8051
8052 /**
8053 * ftrace_is_dead - Test if ftrace is dead or not.
8054 *
8055 * Returns 1 if ftrace is "dead", zero otherwise.
8056 */
ftrace_is_dead(void)8057 int ftrace_is_dead(void)
8058 {
8059 return ftrace_disabled;
8060 }
8061
8062 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
8063 /*
8064 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
8065 * it doesn't conflict with any direct ftrace_ops. If there is existing
8066 * direct ftrace_ops on a kernel function being patched, call
8067 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
8068 *
8069 * @ops: ftrace_ops being registered.
8070 *
8071 * Returns:
8072 * 0 on success;
8073 * Negative on failure.
8074 */
prepare_direct_functions_for_ipmodify(struct ftrace_ops * ops)8075 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8076 {
8077 struct ftrace_func_entry *entry;
8078 struct ftrace_hash *hash;
8079 struct ftrace_ops *op;
8080 int size, i, ret;
8081
8082 lockdep_assert_held_once(&direct_mutex);
8083
8084 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8085 return 0;
8086
8087 hash = ops->func_hash->filter_hash;
8088 size = 1 << hash->size_bits;
8089 for (i = 0; i < size; i++) {
8090 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8091 unsigned long ip = entry->ip;
8092 bool found_op = false;
8093
8094 mutex_lock(&ftrace_lock);
8095 do_for_each_ftrace_op(op, ftrace_ops_list) {
8096 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8097 continue;
8098 if (ops_references_ip(op, ip)) {
8099 found_op = true;
8100 break;
8101 }
8102 } while_for_each_ftrace_op(op);
8103 mutex_unlock(&ftrace_lock);
8104
8105 if (found_op) {
8106 if (!op->ops_func)
8107 return -EBUSY;
8108
8109 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
8110 if (ret)
8111 return ret;
8112 }
8113 }
8114 }
8115
8116 return 0;
8117 }
8118
8119 /*
8120 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
8121 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
8122 * ops.
8123 */
cleanup_direct_functions_after_ipmodify(struct ftrace_ops * ops)8124 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8125 {
8126 struct ftrace_func_entry *entry;
8127 struct ftrace_hash *hash;
8128 struct ftrace_ops *op;
8129 int size, i;
8130
8131 if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8132 return;
8133
8134 mutex_lock(&direct_mutex);
8135
8136 hash = ops->func_hash->filter_hash;
8137 size = 1 << hash->size_bits;
8138 for (i = 0; i < size; i++) {
8139 hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8140 unsigned long ip = entry->ip;
8141 bool found_op = false;
8142
8143 mutex_lock(&ftrace_lock);
8144 do_for_each_ftrace_op(op, ftrace_ops_list) {
8145 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8146 continue;
8147 if (ops_references_ip(op, ip)) {
8148 found_op = true;
8149 break;
8150 }
8151 } while_for_each_ftrace_op(op);
8152 mutex_unlock(&ftrace_lock);
8153
8154 /* The cleanup is optional, ignore any errors */
8155 if (found_op && op->ops_func)
8156 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8157 }
8158 }
8159 mutex_unlock(&direct_mutex);
8160 }
8161
8162 #define lock_direct_mutex() mutex_lock(&direct_mutex)
8163 #define unlock_direct_mutex() mutex_unlock(&direct_mutex)
8164
8165 #else /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8166
prepare_direct_functions_for_ipmodify(struct ftrace_ops * ops)8167 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8168 {
8169 return 0;
8170 }
8171
cleanup_direct_functions_after_ipmodify(struct ftrace_ops * ops)8172 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8173 {
8174 }
8175
8176 #define lock_direct_mutex() do { } while (0)
8177 #define unlock_direct_mutex() do { } while (0)
8178
8179 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8180
8181 /*
8182 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8183 */
register_ftrace_function_nolock(struct ftrace_ops * ops)8184 static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8185 {
8186 int ret;
8187
8188 ftrace_ops_init(ops);
8189
8190 mutex_lock(&ftrace_lock);
8191
8192 ret = ftrace_startup(ops, 0);
8193
8194 mutex_unlock(&ftrace_lock);
8195
8196 return ret;
8197 }
8198
8199 /**
8200 * register_ftrace_function - register a function for profiling
8201 * @ops: ops structure that holds the function for profiling.
8202 *
8203 * Register a function to be called by all functions in the
8204 * kernel.
8205 *
8206 * Note: @ops->func and all the functions it calls must be labeled
8207 * with "notrace", otherwise it will go into a
8208 * recursive loop.
8209 */
register_ftrace_function(struct ftrace_ops * ops)8210 int register_ftrace_function(struct ftrace_ops *ops)
8211 {
8212 int ret;
8213
8214 lock_direct_mutex();
8215 ret = prepare_direct_functions_for_ipmodify(ops);
8216 if (ret < 0)
8217 goto out_unlock;
8218
8219 ret = register_ftrace_function_nolock(ops);
8220
8221 out_unlock:
8222 unlock_direct_mutex();
8223 return ret;
8224 }
8225 EXPORT_SYMBOL_GPL(register_ftrace_function);
8226
8227 /**
8228 * unregister_ftrace_function - unregister a function for profiling.
8229 * @ops: ops structure that holds the function to unregister
8230 *
8231 * Unregister a function that was added to be called by ftrace profiling.
8232 */
unregister_ftrace_function(struct ftrace_ops * ops)8233 int unregister_ftrace_function(struct ftrace_ops *ops)
8234 {
8235 int ret;
8236
8237 mutex_lock(&ftrace_lock);
8238 ret = ftrace_shutdown(ops, 0);
8239 mutex_unlock(&ftrace_lock);
8240
8241 cleanup_direct_functions_after_ipmodify(ops);
8242 return ret;
8243 }
8244 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8245
symbols_cmp(const void * a,const void * b)8246 static int symbols_cmp(const void *a, const void *b)
8247 {
8248 const char **str_a = (const char **) a;
8249 const char **str_b = (const char **) b;
8250
8251 return strcmp(*str_a, *str_b);
8252 }
8253
8254 struct kallsyms_data {
8255 unsigned long *addrs;
8256 const char **syms;
8257 size_t cnt;
8258 size_t found;
8259 };
8260
kallsyms_callback(void * data,const char * name,struct module * mod,unsigned long addr)8261 static int kallsyms_callback(void *data, const char *name,
8262 struct module *mod, unsigned long addr)
8263 {
8264 struct kallsyms_data *args = data;
8265 const char **sym;
8266 int idx;
8267
8268 sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8269 if (!sym)
8270 return 0;
8271
8272 idx = sym - args->syms;
8273 if (args->addrs[idx])
8274 return 0;
8275
8276 if (!ftrace_location(addr))
8277 return 0;
8278
8279 args->addrs[idx] = addr;
8280 args->found++;
8281 return args->found == args->cnt ? 1 : 0;
8282 }
8283
8284 /**
8285 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8286 *
8287 * @sorted_syms: array of symbols pointers symbols to resolve,
8288 * must be alphabetically sorted
8289 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8290 * @addrs: array for storing resulting addresses
8291 *
8292 * This function looks up addresses for array of symbols provided in
8293 * @syms array (must be alphabetically sorted) and stores them in
8294 * @addrs array, which needs to be big enough to store at least @cnt
8295 * addresses.
8296 *
8297 * This function returns 0 if all provided symbols are found,
8298 * -ESRCH otherwise.
8299 */
ftrace_lookup_symbols(const char ** sorted_syms,size_t cnt,unsigned long * addrs)8300 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8301 {
8302 struct kallsyms_data args;
8303 int err;
8304
8305 memset(addrs, 0, sizeof(*addrs) * cnt);
8306 args.addrs = addrs;
8307 args.syms = sorted_syms;
8308 args.cnt = cnt;
8309 args.found = 0;
8310 err = kallsyms_on_each_symbol(kallsyms_callback, &args);
8311 if (err < 0)
8312 return err;
8313 return args.found == args.cnt ? 0 : -ESRCH;
8314 }
8315
8316 #ifdef CONFIG_SYSCTL
8317
8318 #ifdef CONFIG_DYNAMIC_FTRACE
ftrace_startup_sysctl(void)8319 static void ftrace_startup_sysctl(void)
8320 {
8321 int command;
8322
8323 if (unlikely(ftrace_disabled))
8324 return;
8325
8326 /* Force update next time */
8327 saved_ftrace_func = NULL;
8328 /* ftrace_start_up is true if we want ftrace running */
8329 if (ftrace_start_up) {
8330 command = FTRACE_UPDATE_CALLS;
8331 if (ftrace_graph_active)
8332 command |= FTRACE_START_FUNC_RET;
8333 ftrace_startup_enable(command);
8334 }
8335 }
8336
ftrace_shutdown_sysctl(void)8337 static void ftrace_shutdown_sysctl(void)
8338 {
8339 int command;
8340
8341 if (unlikely(ftrace_disabled))
8342 return;
8343
8344 /* ftrace_start_up is true if ftrace is running */
8345 if (ftrace_start_up) {
8346 command = FTRACE_DISABLE_CALLS;
8347 if (ftrace_graph_active)
8348 command |= FTRACE_STOP_FUNC_RET;
8349 ftrace_run_update_code(command);
8350 }
8351 }
8352 #else
8353 # define ftrace_startup_sysctl() do { } while (0)
8354 # define ftrace_shutdown_sysctl() do { } while (0)
8355 #endif /* CONFIG_DYNAMIC_FTRACE */
8356
is_permanent_ops_registered(void)8357 static bool is_permanent_ops_registered(void)
8358 {
8359 struct ftrace_ops *op;
8360
8361 do_for_each_ftrace_op(op, ftrace_ops_list) {
8362 if (op->flags & FTRACE_OPS_FL_PERMANENT)
8363 return true;
8364 } while_for_each_ftrace_op(op);
8365
8366 return false;
8367 }
8368
8369 static int
ftrace_enable_sysctl(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)8370 ftrace_enable_sysctl(struct ctl_table *table, int write,
8371 void *buffer, size_t *lenp, loff_t *ppos)
8372 {
8373 int ret = -ENODEV;
8374
8375 mutex_lock(&ftrace_lock);
8376
8377 if (unlikely(ftrace_disabled))
8378 goto out;
8379
8380 ret = proc_dointvec(table, write, buffer, lenp, ppos);
8381
8382 if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8383 goto out;
8384
8385 if (ftrace_enabled) {
8386
8387 /* we are starting ftrace again */
8388 if (rcu_dereference_protected(ftrace_ops_list,
8389 lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8390 update_ftrace_function();
8391
8392 ftrace_startup_sysctl();
8393
8394 } else {
8395 if (is_permanent_ops_registered()) {
8396 ftrace_enabled = true;
8397 ret = -EBUSY;
8398 goto out;
8399 }
8400
8401 /* stopping ftrace calls (just send to ftrace_stub) */
8402 ftrace_trace_function = ftrace_stub;
8403
8404 ftrace_shutdown_sysctl();
8405 }
8406
8407 last_ftrace_enabled = !!ftrace_enabled;
8408 out:
8409 mutex_unlock(&ftrace_lock);
8410 return ret;
8411 }
8412
8413 static struct ctl_table ftrace_sysctls[] = {
8414 {
8415 .procname = "ftrace_enabled",
8416 .data = &ftrace_enabled,
8417 .maxlen = sizeof(int),
8418 .mode = 0644,
8419 .proc_handler = ftrace_enable_sysctl,
8420 },
8421 {}
8422 };
8423
ftrace_sysctl_init(void)8424 static int __init ftrace_sysctl_init(void)
8425 {
8426 register_sysctl_init("kernel", ftrace_sysctls);
8427 return 0;
8428 }
8429 late_initcall(ftrace_sysctl_init);
8430 #endif
8431