Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...
[drm/drm-misc.git] / include / linux / kprobes.h
blob8c4f3bb2442950d77875b6262409a92569549ca8
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 #ifndef _LINUX_KPROBES_H
3 #define _LINUX_KPROBES_H
4 /*
5 * Kernel Probes (KProbes)
7 * Copyright (C) IBM Corporation, 2002, 2004
9 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
10 * Probes initial implementation ( includes suggestions from
11 * Rusty Russell).
12 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
13 * interface to access function arguments.
14 * 2005-May Hien Nguyen <hien@us.ibm.com> and Jim Keniston
15 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
16 * <prasanna@in.ibm.com> added function-return probes.
18 #include <linux/compiler.h>
19 #include <linux/linkage.h>
20 #include <linux/list.h>
21 #include <linux/notifier.h>
22 #include <linux/smp.h>
23 #include <linux/bug.h>
24 #include <linux/percpu.h>
25 #include <linux/spinlock.h>
26 #include <linux/rcupdate.h>
27 #include <linux/mutex.h>
28 #include <linux/ftrace.h>
29 #include <linux/objpool.h>
30 #include <linux/rethook.h>
31 #include <asm/kprobes.h>
33 #ifdef CONFIG_KPROBES
35 /* kprobe_status settings */
36 #define KPROBE_HIT_ACTIVE 0x00000001
37 #define KPROBE_HIT_SS 0x00000002
38 #define KPROBE_REENTER 0x00000004
39 #define KPROBE_HIT_SSDONE 0x00000008
41 #else /* !CONFIG_KPROBES */
42 #include <asm-generic/kprobes.h>
43 typedef int kprobe_opcode_t;
44 struct arch_specific_insn {
45 int dummy;
47 #endif /* CONFIG_KPROBES */
49 struct kprobe;
50 struct pt_regs;
51 struct kretprobe;
52 struct kretprobe_instance;
53 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
54 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
55 unsigned long flags);
56 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
57 struct pt_regs *);
59 struct kprobe {
60 struct hlist_node hlist;
62 /* list of kprobes for multi-handler support */
63 struct list_head list;
65 /*count the number of times this probe was temporarily disarmed */
66 unsigned long nmissed;
68 /* location of the probe point */
69 kprobe_opcode_t *addr;
71 /* Allow user to indicate symbol name of the probe point */
72 const char *symbol_name;
74 /* Offset into the symbol */
75 unsigned int offset;
77 /* Called before addr is executed. */
78 kprobe_pre_handler_t pre_handler;
80 /* Called after addr is executed, unless... */
81 kprobe_post_handler_t post_handler;
83 /* Saved opcode (which has been replaced with breakpoint) */
84 kprobe_opcode_t opcode;
86 /* copy of the original instruction */
87 struct arch_specific_insn ainsn;
90 * Indicates various status flags.
91 * Protected by kprobe_mutex after this kprobe is registered.
93 u32 flags;
96 /* Kprobe status flags */
97 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
98 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
99 #define KPROBE_FLAG_OPTIMIZED 4 /*
100 * probe is really optimized.
101 * NOTE:
102 * this flag is only for optimized_kprobe.
104 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
105 #define KPROBE_FLAG_ON_FUNC_ENTRY 16 /* probe is on the function entry */
107 /* Has this kprobe gone ? */
108 static inline bool kprobe_gone(struct kprobe *p)
110 return p->flags & KPROBE_FLAG_GONE;
113 /* Is this kprobe disabled ? */
114 static inline bool kprobe_disabled(struct kprobe *p)
116 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
119 /* Is this kprobe really running optimized path ? */
120 static inline bool kprobe_optimized(struct kprobe *p)
122 return p->flags & KPROBE_FLAG_OPTIMIZED;
125 /* Is this kprobe uses ftrace ? */
126 static inline bool kprobe_ftrace(struct kprobe *p)
128 return p->flags & KPROBE_FLAG_FTRACE;
132 * Function-return probe -
133 * Note:
134 * User needs to provide a handler function, and initialize maxactive.
135 * maxactive - The maximum number of instances of the probed function that
136 * can be active concurrently.
137 * nmissed - tracks the number of times the probed function's return was
138 * ignored, due to maxactive being too low.
141 struct kretprobe_holder {
142 struct kretprobe __rcu *rp;
143 struct objpool_head pool;
146 struct kretprobe {
147 struct kprobe kp;
148 kretprobe_handler_t handler;
149 kretprobe_handler_t entry_handler;
150 int maxactive;
151 int nmissed;
152 size_t data_size;
153 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
154 struct rethook *rh;
155 #else
156 struct kretprobe_holder *rph;
157 #endif
160 #define KRETPROBE_MAX_DATA_SIZE 4096
162 struct kretprobe_instance {
163 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
164 struct rethook_node node;
165 #else
166 struct rcu_head rcu;
167 struct llist_node llist;
168 struct kretprobe_holder *rph;
169 kprobe_opcode_t *ret_addr;
170 void *fp;
171 #endif
172 char data[];
175 struct kretprobe_blackpoint {
176 const char *name;
177 void *addr;
180 struct kprobe_blacklist_entry {
181 struct list_head list;
182 unsigned long start_addr;
183 unsigned long end_addr;
186 #ifdef CONFIG_KPROBES
187 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
188 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
190 extern void kprobe_busy_begin(void);
191 extern void kprobe_busy_end(void);
193 #ifdef CONFIG_KRETPROBES
194 /* Check whether @p is used for implementing a trampoline. */
195 extern int arch_trampoline_kprobe(struct kprobe *p);
197 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
198 static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
200 /* rethook::data is non-changed field, so that you can access it freely. */
201 return (struct kretprobe *)ri->node.rethook->data;
203 static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
205 return ri->node.ret_addr;
207 #else
208 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
209 struct pt_regs *regs);
210 void arch_kretprobe_fixup_return(struct pt_regs *regs,
211 kprobe_opcode_t *correct_ret_addr);
213 void __kretprobe_trampoline(void);
215 * Since some architecture uses structured function pointer,
216 * use dereference_function_descriptor() to get real function address.
218 static nokprobe_inline void *kretprobe_trampoline_addr(void)
220 return dereference_kernel_function_descriptor(__kretprobe_trampoline);
223 /* If the trampoline handler called from a kprobe, use this version */
224 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
225 void *frame_pointer);
227 static nokprobe_inline
228 unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
229 void *frame_pointer)
231 unsigned long ret;
233 * Set a dummy kprobe for avoiding kretprobe recursion.
234 * Since kretprobe never runs in kprobe handler, no kprobe must
235 * be running at this point.
237 kprobe_busy_begin();
238 ret = __kretprobe_trampoline_handler(regs, frame_pointer);
239 kprobe_busy_end();
241 return ret;
244 static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
246 return rcu_dereference_check(ri->rph->rp, rcu_read_lock_any_held());
249 static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
251 return (unsigned long)ri->ret_addr;
253 #endif /* CONFIG_KRETPROBE_ON_RETHOOK */
255 #else /* !CONFIG_KRETPROBES */
256 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
257 struct pt_regs *regs)
260 static inline int arch_trampoline_kprobe(struct kprobe *p)
262 return 0;
264 #endif /* CONFIG_KRETPROBES */
266 /* Markers of '_kprobe_blacklist' section */
267 extern unsigned long __start_kprobe_blacklist[];
268 extern unsigned long __stop_kprobe_blacklist[];
270 extern struct kretprobe_blackpoint kretprobe_blacklist[];
272 extern int arch_prepare_kprobe(struct kprobe *p);
273 extern void arch_arm_kprobe(struct kprobe *p);
274 extern void arch_disarm_kprobe(struct kprobe *p);
275 extern int arch_init_kprobes(void);
276 extern void kprobes_inc_nmissed_count(struct kprobe *p);
277 extern bool arch_within_kprobe_blacklist(unsigned long addr);
278 extern int arch_populate_kprobe_blacklist(void);
279 extern int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
281 extern bool within_kprobe_blacklist(unsigned long addr);
282 extern int kprobe_add_ksym_blacklist(unsigned long entry);
283 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
285 struct kprobe_insn_cache {
286 struct mutex mutex;
287 void *(*alloc)(void); /* allocate insn page */
288 void (*free)(void *); /* free insn page */
289 const char *sym; /* symbol for insn pages */
290 struct list_head pages; /* list of kprobe_insn_page */
291 size_t insn_size; /* size of instruction slot */
292 int nr_garbage;
295 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
296 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
297 extern void __free_insn_slot(struct kprobe_insn_cache *c,
298 kprobe_opcode_t *slot, int dirty);
299 /* sleep-less address checking routine */
300 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
301 unsigned long addr);
303 #define DEFINE_INSN_CACHE_OPS(__name) \
304 extern struct kprobe_insn_cache kprobe_##__name##_slots; \
306 static inline kprobe_opcode_t *get_##__name##_slot(void) \
308 return __get_insn_slot(&kprobe_##__name##_slots); \
311 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
313 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
316 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
318 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
320 #define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
321 #define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
322 int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
323 unsigned long *value, char *type, char *sym);
324 #else /* !__ARCH_WANT_KPROBES_INSN_SLOT */
325 #define DEFINE_INSN_CACHE_OPS(__name) \
326 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
328 return 0; \
330 #endif
332 DEFINE_INSN_CACHE_OPS(insn);
334 #ifdef CONFIG_OPTPROBES
336 * Internal structure for direct jump optimized probe
338 struct optimized_kprobe {
339 struct kprobe kp;
340 struct list_head list; /* list for optimizing queue */
341 struct arch_optimized_insn optinsn;
344 /* Architecture dependent functions for direct jump optimization */
345 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
346 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
347 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
348 struct kprobe *orig);
349 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
350 extern void arch_optimize_kprobes(struct list_head *oplist);
351 extern void arch_unoptimize_kprobes(struct list_head *oplist,
352 struct list_head *done_list);
353 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
354 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
355 kprobe_opcode_t *addr);
357 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
359 DEFINE_INSN_CACHE_OPS(optinsn);
361 extern void wait_for_kprobe_optimizer(void);
362 bool optprobe_queued_unopt(struct optimized_kprobe *op);
363 bool kprobe_disarmed(struct kprobe *p);
364 #else /* !CONFIG_OPTPROBES */
365 static inline void wait_for_kprobe_optimizer(void) { }
366 #endif /* CONFIG_OPTPROBES */
368 #ifdef CONFIG_KPROBES_ON_FTRACE
369 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
370 struct ftrace_ops *ops, struct ftrace_regs *fregs);
371 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
372 /* Set when ftrace has been killed: kprobes on ftrace must be disabled for safety */
373 extern bool kprobe_ftrace_disabled __read_mostly;
374 extern void kprobe_ftrace_kill(void);
375 #else
376 static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
378 return -EINVAL;
380 static inline void kprobe_ftrace_kill(void) {}
381 #endif /* CONFIG_KPROBES_ON_FTRACE */
383 /* Get the kprobe at this addr (if any) - called with preemption disabled */
384 struct kprobe *get_kprobe(void *addr);
386 /* kprobe_running() will just return the current_kprobe on this CPU */
387 static inline struct kprobe *kprobe_running(void)
389 return __this_cpu_read(current_kprobe);
392 static inline void reset_current_kprobe(void)
394 __this_cpu_write(current_kprobe, NULL);
397 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
399 return this_cpu_ptr(&kprobe_ctlblk);
402 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
403 kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry);
405 int register_kprobe(struct kprobe *p);
406 void unregister_kprobe(struct kprobe *p);
407 int register_kprobes(struct kprobe **kps, int num);
408 void unregister_kprobes(struct kprobe **kps, int num);
410 int register_kretprobe(struct kretprobe *rp);
411 void unregister_kretprobe(struct kretprobe *rp);
412 int register_kretprobes(struct kretprobe **rps, int num);
413 void unregister_kretprobes(struct kretprobe **rps, int num);
415 #if defined(CONFIG_KRETPROBE_ON_RETHOOK) || !defined(CONFIG_KRETPROBES)
416 #define kprobe_flush_task(tk) do {} while (0)
417 #else
418 void kprobe_flush_task(struct task_struct *tk);
419 #endif
421 void kprobe_free_init_mem(void);
423 int disable_kprobe(struct kprobe *kp);
424 int enable_kprobe(struct kprobe *kp);
426 void dump_kprobe(struct kprobe *kp);
428 void *alloc_insn_page(void);
430 void *alloc_optinsn_page(void);
431 void free_optinsn_page(void *page);
433 int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
434 char *sym);
436 int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
437 char *type, char *sym);
439 int kprobe_exceptions_notify(struct notifier_block *self,
440 unsigned long val, void *data);
442 #else /* !CONFIG_KPROBES: */
444 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
446 return 0;
448 static inline struct kprobe *get_kprobe(void *addr)
450 return NULL;
452 static inline struct kprobe *kprobe_running(void)
454 return NULL;
456 #define kprobe_busy_begin() do {} while (0)
457 #define kprobe_busy_end() do {} while (0)
459 static inline int register_kprobe(struct kprobe *p)
461 return -EOPNOTSUPP;
463 static inline int register_kprobes(struct kprobe **kps, int num)
465 return -EOPNOTSUPP;
467 static inline void unregister_kprobe(struct kprobe *p)
470 static inline void unregister_kprobes(struct kprobe **kps, int num)
473 static inline int register_kretprobe(struct kretprobe *rp)
475 return -EOPNOTSUPP;
477 static inline int register_kretprobes(struct kretprobe **rps, int num)
479 return -EOPNOTSUPP;
481 static inline void unregister_kretprobe(struct kretprobe *rp)
484 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
487 static inline void kprobe_flush_task(struct task_struct *tk)
490 static inline void kprobe_free_init_mem(void)
493 static inline void kprobe_ftrace_kill(void)
496 static inline int disable_kprobe(struct kprobe *kp)
498 return -EOPNOTSUPP;
500 static inline int enable_kprobe(struct kprobe *kp)
502 return -EOPNOTSUPP;
505 static inline bool within_kprobe_blacklist(unsigned long addr)
507 return true;
509 static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
510 char *type, char *sym)
512 return -ERANGE;
514 #endif /* CONFIG_KPROBES */
516 static inline int disable_kretprobe(struct kretprobe *rp)
518 return disable_kprobe(&rp->kp);
520 static inline int enable_kretprobe(struct kretprobe *rp)
522 return enable_kprobe(&rp->kp);
525 #ifndef CONFIG_KPROBES
526 static inline bool is_kprobe_insn_slot(unsigned long addr)
528 return false;
530 #endif /* !CONFIG_KPROBES */
532 #ifndef CONFIG_OPTPROBES
533 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
535 return false;
537 #endif /* !CONFIG_OPTPROBES */
539 #ifdef CONFIG_KRETPROBES
540 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
541 static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
543 return is_rethook_trampoline(addr);
546 static nokprobe_inline
547 unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
548 struct llist_node **cur)
550 return rethook_find_ret_addr(tsk, (unsigned long)fp, cur);
552 #else
553 static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
555 return (void *)addr == kretprobe_trampoline_addr();
558 unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
559 struct llist_node **cur);
560 #endif
561 #else
562 static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
564 return false;
567 static nokprobe_inline
568 unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
569 struct llist_node **cur)
571 return 0;
573 #endif
575 /* Returns true if kprobes handled the fault */
576 static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
577 unsigned int trap)
579 if (!IS_ENABLED(CONFIG_KPROBES))
580 return false;
581 if (user_mode(regs))
582 return false;
584 * To be potentially processing a kprobe fault and to be allowed
585 * to call kprobe_running(), we have to be non-preemptible.
587 if (preemptible())
588 return false;
589 if (!kprobe_running())
590 return false;
591 return kprobe_fault_handler(regs, trap);
594 #endif /* _LINUX_KPROBES_H */