1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 #ifndef _LINUX_KPROBES_H
3 #define _LINUX_KPROBES_H
4 /*
5 * Kernel Probes (KProbes)
6 * include/linux/kprobes.h
7 *
8 * Copyright (C) IBM Corporation, 2002, 2004
9 *
10 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
11 * Probes initial implementation ( includes suggestions from
12 * Rusty Russell).
13 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
14 * interface to access function arguments.
15 * 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston
16 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
17 * <prasanna@in.ibm.com> added function-return probes.
18 */
19 #include <linux/compiler.h>
20 #include <linux/linkage.h>
21 #include <linux/list.h>
22 #include <linux/notifier.h>
23 #include <linux/smp.h>
24 #include <linux/bug.h>
25 #include <linux/percpu.h>
26 #include <linux/spinlock.h>
27 #include <linux/rcupdate.h>
28 #include <linux/mutex.h>
29 #include <linux/ftrace.h>
30 #include <asm/kprobes.h>
31
32 #ifdef CONFIG_KPROBES
33
34 /* kprobe_status settings */
35 #define KPROBE_HIT_ACTIVE 0x00000001
36 #define KPROBE_HIT_SS 0x00000002
37 #define KPROBE_REENTER 0x00000004
38 #define KPROBE_HIT_SSDONE 0x00000008
39
40 #else /* CONFIG_KPROBES */
41 #include <asm-generic/kprobes.h>
42 typedef int kprobe_opcode_t;
43 struct arch_specific_insn {
44 int dummy;
45 };
46 #endif /* CONFIG_KPROBES */
47
48 struct kprobe;
49 struct pt_regs;
50 struct kretprobe;
51 struct kretprobe_instance;
52 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
53 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
54 unsigned long flags);
55 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
56 int trapnr);
57 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
58 struct pt_regs *);
59
60 struct kprobe {
61 struct hlist_node hlist;
62
63 /* list of kprobes for multi-handler support */
64 struct list_head list;
65
66 /*count the number of times this probe was temporarily disarmed */
67 unsigned long nmissed;
68
69 /* location of the probe point */
70 kprobe_opcode_t *addr;
71
72 /* Allow user to indicate symbol name of the probe point */
73 const char *symbol_name;
74
75 /* Offset into the symbol */
76 unsigned int offset;
77
78 /* Called before addr is executed. */
79 kprobe_pre_handler_t pre_handler;
80
81 /* Called after addr is executed, unless... */
82 kprobe_post_handler_t post_handler;
83
84 /*
85 * ... called if executing addr causes a fault (eg. page fault).
86 * Return 1 if it handled fault, otherwise kernel will see it.
87 */
88 kprobe_fault_handler_t fault_handler;
89
90 /* Saved opcode (which has been replaced with breakpoint) */
91 kprobe_opcode_t opcode;
92
93 /* copy of the original instruction */
94 struct arch_specific_insn ainsn;
95
96 /*
97 * Indicates various status flags.
98 * Protected by kprobe_mutex after this kprobe is registered.
99 */
100 u32 flags;
101 };
102
103 /* Kprobe status flags */
104 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
105 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
106 #define KPROBE_FLAG_OPTIMIZED 4 /*
107 * probe is really optimized.
108 * NOTE:
109 * this flag is only for optimized_kprobe.
110 */
111 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
112
113 /* Has this kprobe gone ? */
kprobe_gone(struct kprobe * p)114 static inline int kprobe_gone(struct kprobe *p)
115 {
116 return p->flags & KPROBE_FLAG_GONE;
117 }
118
119 /* Is this kprobe disabled ? */
kprobe_disabled(struct kprobe * p)120 static inline int kprobe_disabled(struct kprobe *p)
121 {
122 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
123 }
124
125 /* Is this kprobe really running optimized path ? */
kprobe_optimized(struct kprobe * p)126 static inline int kprobe_optimized(struct kprobe *p)
127 {
128 return p->flags & KPROBE_FLAG_OPTIMIZED;
129 }
130
131 /* Is this kprobe uses ftrace ? */
kprobe_ftrace(struct kprobe * p)132 static inline int kprobe_ftrace(struct kprobe *p)
133 {
134 return p->flags & KPROBE_FLAG_FTRACE;
135 }
136
137 /*
138 * Function-return probe -
139 * Note:
140 * User needs to provide a handler function, and initialize maxactive.
141 * maxactive - The maximum number of instances of the probed function that
142 * can be active concurrently.
143 * nmissed - tracks the number of times the probed function's return was
144 * ignored, due to maxactive being too low.
145 *
146 */
147 struct kretprobe {
148 struct kprobe kp;
149 kretprobe_handler_t handler;
150 kretprobe_handler_t entry_handler;
151 int maxactive;
152 int nmissed;
153 size_t data_size;
154 struct hlist_head free_instances;
155 raw_spinlock_t lock;
156 };
157
158 struct kretprobe_instance {
159 union {
160 struct hlist_node hlist;
161 struct rcu_head rcu;
162 };
163 struct kretprobe *rp;
164 kprobe_opcode_t *ret_addr;
165 struct task_struct *task;
166 void *fp;
167 char data[];
168 };
169
170 struct kretprobe_blackpoint {
171 const char *name;
172 void *addr;
173 };
174
175 struct kprobe_blacklist_entry {
176 struct list_head list;
177 unsigned long start_addr;
178 unsigned long end_addr;
179 };
180
181 #ifdef CONFIG_KPROBES
182 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
183 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
184
185 /*
186 * For #ifdef avoidance:
187 */
kprobes_built_in(void)188 static inline int kprobes_built_in(void)
189 {
190 return 1;
191 }
192
193 extern void kprobe_busy_begin(void);
194 extern void kprobe_busy_end(void);
195
196 #ifdef CONFIG_KRETPROBES
197 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
198 struct pt_regs *regs);
199 extern int arch_trampoline_kprobe(struct kprobe *p);
200
201 /* If the trampoline handler called from a kprobe, use this version */
202 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
203 void *trampoline_address,
204 void *frame_pointer);
205
206 static nokprobe_inline
kretprobe_trampoline_handler(struct pt_regs * regs,void * trampoline_address,void * frame_pointer)207 unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
208 void *trampoline_address,
209 void *frame_pointer)
210 {
211 unsigned long ret;
212 /*
213 * Set a dummy kprobe for avoiding kretprobe recursion.
214 * Since kretprobe never runs in kprobe handler, no kprobe must
215 * be running at this point.
216 */
217 kprobe_busy_begin();
218 ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer);
219 kprobe_busy_end();
220
221 return ret;
222 }
223
224 #else /* CONFIG_KRETPROBES */
arch_prepare_kretprobe(struct kretprobe * rp,struct pt_regs * regs)225 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
226 struct pt_regs *regs)
227 {
228 }
arch_trampoline_kprobe(struct kprobe * p)229 static inline int arch_trampoline_kprobe(struct kprobe *p)
230 {
231 return 0;
232 }
233 #endif /* CONFIG_KRETPROBES */
234
235 extern struct kretprobe_blackpoint kretprobe_blacklist[];
236
237 #ifdef CONFIG_KPROBES_SANITY_TEST
238 extern int init_test_probes(void);
239 #else
init_test_probes(void)240 static inline int init_test_probes(void)
241 {
242 return 0;
243 }
244 #endif /* CONFIG_KPROBES_SANITY_TEST */
245
246 extern int arch_prepare_kprobe(struct kprobe *p);
247 extern void arch_arm_kprobe(struct kprobe *p);
248 extern void arch_disarm_kprobe(struct kprobe *p);
249 extern int arch_init_kprobes(void);
250 extern void kprobes_inc_nmissed_count(struct kprobe *p);
251 extern bool arch_within_kprobe_blacklist(unsigned long addr);
252 extern int arch_populate_kprobe_blacklist(void);
253 extern bool arch_kprobe_on_func_entry(unsigned long offset);
254 extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
255
256 extern bool within_kprobe_blacklist(unsigned long addr);
257 extern int kprobe_add_ksym_blacklist(unsigned long entry);
258 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
259
260 struct kprobe_insn_cache {
261 struct mutex mutex;
262 void *(*alloc)(void); /* allocate insn page */
263 void (*free)(void *); /* free insn page */
264 const char *sym; /* symbol for insn pages */
265 struct list_head pages; /* list of kprobe_insn_page */
266 size_t insn_size; /* size of instruction slot */
267 int nr_garbage;
268 };
269
270 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
271 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
272 extern void __free_insn_slot(struct kprobe_insn_cache *c,
273 kprobe_opcode_t *slot, int dirty);
274 /* sleep-less address checking routine */
275 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
276 unsigned long addr);
277
278 #define DEFINE_INSN_CACHE_OPS(__name) \
279 extern struct kprobe_insn_cache kprobe_##__name##_slots; \
280 \
281 static inline kprobe_opcode_t *get_##__name##_slot(void) \
282 { \
283 return __get_insn_slot(&kprobe_##__name##_slots); \
284 } \
285 \
286 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
287 { \
288 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
289 } \
290 \
291 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
292 { \
293 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
294 }
295 #define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
296 #define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
297 int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
298 unsigned long *value, char *type, char *sym);
299 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */
300 #define DEFINE_INSN_CACHE_OPS(__name) \
301 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
302 { \
303 return 0; \
304 }
305 #endif
306
307 DEFINE_INSN_CACHE_OPS(insn);
308
309 #ifdef CONFIG_OPTPROBES
310 /*
311 * Internal structure for direct jump optimized probe
312 */
313 struct optimized_kprobe {
314 struct kprobe kp;
315 struct list_head list; /* list for optimizing queue */
316 struct arch_optimized_insn optinsn;
317 };
318
319 /* Architecture dependent functions for direct jump optimization */
320 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
321 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
322 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
323 struct kprobe *orig);
324 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
325 extern void arch_optimize_kprobes(struct list_head *oplist);
326 extern void arch_unoptimize_kprobes(struct list_head *oplist,
327 struct list_head *done_list);
328 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
329 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
330 unsigned long addr);
331
332 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
333
334 DEFINE_INSN_CACHE_OPS(optinsn);
335
336 #ifdef CONFIG_SYSCTL
337 extern int sysctl_kprobes_optimization;
338 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
339 int write, void *buffer,
340 size_t *length, loff_t *ppos);
341 #endif
342 extern void wait_for_kprobe_optimizer(void);
343 #else
wait_for_kprobe_optimizer(void)344 static inline void wait_for_kprobe_optimizer(void) { }
345 #endif /* CONFIG_OPTPROBES */
346 #ifdef CONFIG_KPROBES_ON_FTRACE
347 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
348 struct ftrace_ops *ops, struct pt_regs *regs);
349 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
350 #endif
351
352 int arch_check_ftrace_location(struct kprobe *p);
353
354 /* Get the kprobe at this addr (if any) - called with preemption disabled */
355 struct kprobe *get_kprobe(void *addr);
356
357 /* kprobe_running() will just return the current_kprobe on this CPU */
kprobe_running(void)358 static inline struct kprobe *kprobe_running(void)
359 {
360 return (__this_cpu_read(current_kprobe));
361 }
362
reset_current_kprobe(void)363 static inline void reset_current_kprobe(void)
364 {
365 __this_cpu_write(current_kprobe, NULL);
366 }
367
get_kprobe_ctlblk(void)368 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
369 {
370 return this_cpu_ptr(&kprobe_ctlblk);
371 }
372
373 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
374 int register_kprobe(struct kprobe *p);
375 void unregister_kprobe(struct kprobe *p);
376 int register_kprobes(struct kprobe **kps, int num);
377 void unregister_kprobes(struct kprobe **kps, int num);
378 unsigned long arch_deref_entry_point(void *);
379
380 int register_kretprobe(struct kretprobe *rp);
381 void unregister_kretprobe(struct kretprobe *rp);
382 int register_kretprobes(struct kretprobe **rps, int num);
383 void unregister_kretprobes(struct kretprobe **rps, int num);
384
385 void kprobe_flush_task(struct task_struct *tk);
386
387 void kprobe_free_init_mem(void);
388
389 int disable_kprobe(struct kprobe *kp);
390 int enable_kprobe(struct kprobe *kp);
391
392 void dump_kprobe(struct kprobe *kp);
393
394 void *alloc_insn_page(void);
395 void free_insn_page(void *page);
396
397 int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
398 char *sym);
399
400 int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
401 char *type, char *sym);
402 #else /* !CONFIG_KPROBES: */
403
kprobes_built_in(void)404 static inline int kprobes_built_in(void)
405 {
406 return 0;
407 }
kprobe_fault_handler(struct pt_regs * regs,int trapnr)408 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
409 {
410 return 0;
411 }
get_kprobe(void * addr)412 static inline struct kprobe *get_kprobe(void *addr)
413 {
414 return NULL;
415 }
kprobe_running(void)416 static inline struct kprobe *kprobe_running(void)
417 {
418 return NULL;
419 }
register_kprobe(struct kprobe * p)420 static inline int register_kprobe(struct kprobe *p)
421 {
422 return -ENOSYS;
423 }
register_kprobes(struct kprobe ** kps,int num)424 static inline int register_kprobes(struct kprobe **kps, int num)
425 {
426 return -ENOSYS;
427 }
unregister_kprobe(struct kprobe * p)428 static inline void unregister_kprobe(struct kprobe *p)
429 {
430 }
unregister_kprobes(struct kprobe ** kps,int num)431 static inline void unregister_kprobes(struct kprobe **kps, int num)
432 {
433 }
register_kretprobe(struct kretprobe * rp)434 static inline int register_kretprobe(struct kretprobe *rp)
435 {
436 return -ENOSYS;
437 }
register_kretprobes(struct kretprobe ** rps,int num)438 static inline int register_kretprobes(struct kretprobe **rps, int num)
439 {
440 return -ENOSYS;
441 }
unregister_kretprobe(struct kretprobe * rp)442 static inline void unregister_kretprobe(struct kretprobe *rp)
443 {
444 }
unregister_kretprobes(struct kretprobe ** rps,int num)445 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
446 {
447 }
kprobe_flush_task(struct task_struct * tk)448 static inline void kprobe_flush_task(struct task_struct *tk)
449 {
450 }
kprobe_free_init_mem(void)451 static inline void kprobe_free_init_mem(void)
452 {
453 }
disable_kprobe(struct kprobe * kp)454 static inline int disable_kprobe(struct kprobe *kp)
455 {
456 return -ENOSYS;
457 }
enable_kprobe(struct kprobe * kp)458 static inline int enable_kprobe(struct kprobe *kp)
459 {
460 return -ENOSYS;
461 }
462
within_kprobe_blacklist(unsigned long addr)463 static inline bool within_kprobe_blacklist(unsigned long addr)
464 {
465 return true;
466 }
kprobe_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * sym)467 static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
468 char *type, char *sym)
469 {
470 return -ERANGE;
471 }
472 #endif /* CONFIG_KPROBES */
disable_kretprobe(struct kretprobe * rp)473 static inline int disable_kretprobe(struct kretprobe *rp)
474 {
475 return disable_kprobe(&rp->kp);
476 }
enable_kretprobe(struct kretprobe * rp)477 static inline int enable_kretprobe(struct kretprobe *rp)
478 {
479 return enable_kprobe(&rp->kp);
480 }
481
482 #ifndef CONFIG_KPROBES
is_kprobe_insn_slot(unsigned long addr)483 static inline bool is_kprobe_insn_slot(unsigned long addr)
484 {
485 return false;
486 }
487 #endif
488 #ifndef CONFIG_OPTPROBES
is_kprobe_optinsn_slot(unsigned long addr)489 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
490 {
491 return false;
492 }
493 #endif
494
495 /* Returns true if kprobes handled the fault */
kprobe_page_fault(struct pt_regs * regs,unsigned int trap)496 static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
497 unsigned int trap)
498 {
499 if (!kprobes_built_in())
500 return false;
501 if (user_mode(regs))
502 return false;
503 /*
504 * To be potentially processing a kprobe fault and to be allowed
505 * to call kprobe_running(), we have to be non-preemptible.
506 */
507 if (preemptible())
508 return false;
509 if (!kprobe_running())
510 return false;
511 return kprobe_fault_handler(regs, trap);
512 }
513
514 #endif /* _LINUX_KPROBES_H */
515
