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 struct hlist_node hlist;
160 struct kretprobe *rp;
161 kprobe_opcode_t *ret_addr;
162 struct task_struct *task;
163 void *fp;
164 char data[0];
165 };
166
167 struct kretprobe_blackpoint {
168 const char *name;
169 void *addr;
170 };
171
172 struct kprobe_blacklist_entry {
173 struct list_head list;
174 unsigned long start_addr;
175 unsigned long end_addr;
176 };
177
178 #ifdef CONFIG_KPROBES
179 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
180 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
181
182 /*
183 * For #ifdef avoidance:
184 */
kprobes_built_in(void)185 static inline int kprobes_built_in(void)
186 {
187 return 1;
188 }
189
190 #ifdef CONFIG_KRETPROBES
191 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
192 struct pt_regs *regs);
193 extern int arch_trampoline_kprobe(struct kprobe *p);
194 #else /* CONFIG_KRETPROBES */
arch_prepare_kretprobe(struct kretprobe * rp,struct pt_regs * regs)195 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
196 struct pt_regs *regs)
197 {
198 }
arch_trampoline_kprobe(struct kprobe * p)199 static inline int arch_trampoline_kprobe(struct kprobe *p)
200 {
201 return 0;
202 }
203 #endif /* CONFIG_KRETPROBES */
204
205 extern struct kretprobe_blackpoint kretprobe_blacklist[];
206
kretprobe_assert(struct kretprobe_instance * ri,unsigned long orig_ret_address,unsigned long trampoline_address)207 static inline void kretprobe_assert(struct kretprobe_instance *ri,
208 unsigned long orig_ret_address, unsigned long trampoline_address)
209 {
210 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
211 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
212 ri->rp, ri->rp->kp.addr);
213 BUG();
214 }
215 }
216
217 #ifdef CONFIG_KPROBES_SANITY_TEST
218 extern int init_test_probes(void);
219 #else
init_test_probes(void)220 static inline int init_test_probes(void)
221 {
222 return 0;
223 }
224 #endif /* CONFIG_KPROBES_SANITY_TEST */
225
226 extern int arch_prepare_kprobe(struct kprobe *p);
227 extern void arch_arm_kprobe(struct kprobe *p);
228 extern void arch_disarm_kprobe(struct kprobe *p);
229 extern int arch_init_kprobes(void);
230 extern void show_registers(struct pt_regs *regs);
231 extern void kprobes_inc_nmissed_count(struct kprobe *p);
232 extern bool arch_within_kprobe_blacklist(unsigned long addr);
233 extern int arch_populate_kprobe_blacklist(void);
234 extern bool arch_kprobe_on_func_entry(unsigned long offset);
235 extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
236
237 extern bool within_kprobe_blacklist(unsigned long addr);
238 extern int kprobe_add_ksym_blacklist(unsigned long entry);
239 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
240
241 struct kprobe_insn_cache {
242 struct mutex mutex;
243 void *(*alloc)(void); /* allocate insn page */
244 void (*free)(void *); /* free insn page */
245 struct list_head pages; /* list of kprobe_insn_page */
246 size_t insn_size; /* size of instruction slot */
247 int nr_garbage;
248 };
249
250 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
251 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
252 extern void __free_insn_slot(struct kprobe_insn_cache *c,
253 kprobe_opcode_t *slot, int dirty);
254 /* sleep-less address checking routine */
255 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
256 unsigned long addr);
257
258 #define DEFINE_INSN_CACHE_OPS(__name) \
259 extern struct kprobe_insn_cache kprobe_##__name##_slots; \
260 \
261 static inline kprobe_opcode_t *get_##__name##_slot(void) \
262 { \
263 return __get_insn_slot(&kprobe_##__name##_slots); \
264 } \
265 \
266 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
267 { \
268 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
269 } \
270 \
271 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
272 { \
273 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
274 }
275 #else /* __ARCH_WANT_KPROBES_INSN_SLOT */
276 #define DEFINE_INSN_CACHE_OPS(__name) \
277 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
278 { \
279 return 0; \
280 }
281 #endif
282
283 DEFINE_INSN_CACHE_OPS(insn);
284
285 #ifdef CONFIG_OPTPROBES
286 /*
287 * Internal structure for direct jump optimized probe
288 */
289 struct optimized_kprobe {
290 struct kprobe kp;
291 struct list_head list; /* list for optimizing queue */
292 struct arch_optimized_insn optinsn;
293 };
294
295 /* Architecture dependent functions for direct jump optimization */
296 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
297 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
298 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
299 struct kprobe *orig);
300 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
301 extern void arch_optimize_kprobes(struct list_head *oplist);
302 extern void arch_unoptimize_kprobes(struct list_head *oplist,
303 struct list_head *done_list);
304 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
305 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
306 unsigned long addr);
307
308 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
309
310 DEFINE_INSN_CACHE_OPS(optinsn);
311
312 #ifdef CONFIG_SYSCTL
313 extern int sysctl_kprobes_optimization;
314 extern int proc_kprobes_optimization_handler(struct ctl_table *table,
315 int write, void __user *buffer,
316 size_t *length, loff_t *ppos);
317 #endif
318 extern void wait_for_kprobe_optimizer(void);
319 #else
wait_for_kprobe_optimizer(void)320 static inline void wait_for_kprobe_optimizer(void) { }
321 #endif /* CONFIG_OPTPROBES */
322 #ifdef CONFIG_KPROBES_ON_FTRACE
323 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
324 struct ftrace_ops *ops, struct pt_regs *regs);
325 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
326 #endif
327
328 int arch_check_ftrace_location(struct kprobe *p);
329
330 /* Get the kprobe at this addr (if any) - called with preemption disabled */
331 struct kprobe *get_kprobe(void *addr);
332 void kretprobe_hash_lock(struct task_struct *tsk,
333 struct hlist_head **head, unsigned long *flags);
334 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
335 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
336
337 /* kprobe_running() will just return the current_kprobe on this CPU */
kprobe_running(void)338 static inline struct kprobe *kprobe_running(void)
339 {
340 return (__this_cpu_read(current_kprobe));
341 }
342
reset_current_kprobe(void)343 static inline void reset_current_kprobe(void)
344 {
345 __this_cpu_write(current_kprobe, NULL);
346 }
347
get_kprobe_ctlblk(void)348 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
349 {
350 return this_cpu_ptr(&kprobe_ctlblk);
351 }
352
353 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
354 int register_kprobe(struct kprobe *p);
355 void unregister_kprobe(struct kprobe *p);
356 int register_kprobes(struct kprobe **kps, int num);
357 void unregister_kprobes(struct kprobe **kps, int num);
358 unsigned long arch_deref_entry_point(void *);
359
360 int register_kretprobe(struct kretprobe *rp);
361 void unregister_kretprobe(struct kretprobe *rp);
362 int register_kretprobes(struct kretprobe **rps, int num);
363 void unregister_kretprobes(struct kretprobe **rps, int num);
364
365 void kprobe_flush_task(struct task_struct *tk);
366 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
367
368 int disable_kprobe(struct kprobe *kp);
369 int enable_kprobe(struct kprobe *kp);
370
371 void dump_kprobe(struct kprobe *kp);
372
373 void *alloc_insn_page(void);
374 void free_insn_page(void *page);
375
376 #else /* !CONFIG_KPROBES: */
377
kprobes_built_in(void)378 static inline int kprobes_built_in(void)
379 {
380 return 0;
381 }
kprobe_fault_handler(struct pt_regs * regs,int trapnr)382 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
383 {
384 return 0;
385 }
get_kprobe(void * addr)386 static inline struct kprobe *get_kprobe(void *addr)
387 {
388 return NULL;
389 }
kprobe_running(void)390 static inline struct kprobe *kprobe_running(void)
391 {
392 return NULL;
393 }
register_kprobe(struct kprobe * p)394 static inline int register_kprobe(struct kprobe *p)
395 {
396 return -ENOSYS;
397 }
register_kprobes(struct kprobe ** kps,int num)398 static inline int register_kprobes(struct kprobe **kps, int num)
399 {
400 return -ENOSYS;
401 }
unregister_kprobe(struct kprobe * p)402 static inline void unregister_kprobe(struct kprobe *p)
403 {
404 }
unregister_kprobes(struct kprobe ** kps,int num)405 static inline void unregister_kprobes(struct kprobe **kps, int num)
406 {
407 }
register_kretprobe(struct kretprobe * rp)408 static inline int register_kretprobe(struct kretprobe *rp)
409 {
410 return -ENOSYS;
411 }
register_kretprobes(struct kretprobe ** rps,int num)412 static inline int register_kretprobes(struct kretprobe **rps, int num)
413 {
414 return -ENOSYS;
415 }
unregister_kretprobe(struct kretprobe * rp)416 static inline void unregister_kretprobe(struct kretprobe *rp)
417 {
418 }
unregister_kretprobes(struct kretprobe ** rps,int num)419 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
420 {
421 }
kprobe_flush_task(struct task_struct * tk)422 static inline void kprobe_flush_task(struct task_struct *tk)
423 {
424 }
disable_kprobe(struct kprobe * kp)425 static inline int disable_kprobe(struct kprobe *kp)
426 {
427 return -ENOSYS;
428 }
enable_kprobe(struct kprobe * kp)429 static inline int enable_kprobe(struct kprobe *kp)
430 {
431 return -ENOSYS;
432 }
433
within_kprobe_blacklist(unsigned long addr)434 static inline bool within_kprobe_blacklist(unsigned long addr)
435 {
436 return true;
437 }
438 #endif /* CONFIG_KPROBES */
disable_kretprobe(struct kretprobe * rp)439 static inline int disable_kretprobe(struct kretprobe *rp)
440 {
441 return disable_kprobe(&rp->kp);
442 }
enable_kretprobe(struct kretprobe * rp)443 static inline int enable_kretprobe(struct kretprobe *rp)
444 {
445 return enable_kprobe(&rp->kp);
446 }
447
448 #ifndef CONFIG_KPROBES
is_kprobe_insn_slot(unsigned long addr)449 static inline bool is_kprobe_insn_slot(unsigned long addr)
450 {
451 return false;
452 }
453 #endif
454 #ifndef CONFIG_OPTPROBES
is_kprobe_optinsn_slot(unsigned long addr)455 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
456 {
457 return false;
458 }
459 #endif
460
461 /* Returns true if kprobes handled the fault */
kprobe_page_fault(struct pt_regs * regs,unsigned int trap)462 static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
463 unsigned int trap)
464 {
465 if (!kprobes_built_in())
466 return false;
467 if (user_mode(regs))
468 return false;
469 /*
470 * To be potentially processing a kprobe fault and to be allowed
471 * to call kprobe_running(), we have to be non-preemptible.
472 */
473 if (preemptible())
474 return false;
475 if (!kprobe_running())
476 return false;
477 return kprobe_fault_handler(regs, trap);
478 }
479
480 #endif /* _LINUX_KPROBES_H */
481