1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 #ifndef _LINUX_KPROBES_H
3 #define _LINUX_KPROBES_H
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
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/refcount.h>
30 #include <linux/freelist.h>
31 #include <linux/rethook.h>
32 #include <asm/kprobes.h>
36 /* kprobe_status settings */
37 #define KPROBE_HIT_ACTIVE 0x00000001
38 #define KPROBE_HIT_SS 0x00000002
39 #define KPROBE_REENTER 0x00000004
40 #define KPROBE_HIT_SSDONE 0x00000008
42 #else /* !CONFIG_KPROBES */
43 #include <asm-generic/kprobes.h>
44 typedef int kprobe_opcode_t;
45 struct arch_specific_insn {
48 #endif /* CONFIG_KPROBES */
53 struct kretprobe_instance;
54 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
55 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
57 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
61 struct hlist_node hlist;
63 /* list of kprobes for multi-handler support */
64 struct list_head list;
66 /*count the number of times this probe was temporarily disarmed */
67 unsigned long nmissed;
69 /* location of the probe point */
70 kprobe_opcode_t *addr;
72 /* Allow user to indicate symbol name of the probe point */
73 const char *symbol_name;
75 /* Offset into the symbol */
78 /* Called before addr is executed. */
79 kprobe_pre_handler_t pre_handler;
81 /* Called after addr is executed, unless... */
82 kprobe_post_handler_t post_handler;
84 /* Saved opcode (which has been replaced with breakpoint) */
85 kprobe_opcode_t opcode;
87 /* copy of the original instruction */
88 struct arch_specific_insn ainsn;
91 * Indicates various status flags.
92 * Protected by kprobe_mutex after this kprobe is registered.
97 /* Kprobe status flags */
98 #define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
99 #define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
100 #define KPROBE_FLAG_OPTIMIZED 4 /*
101 * probe is really optimized.
103 * this flag is only for optimized_kprobe.
105 #define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
106 #define KPROBE_FLAG_ON_FUNC_ENTRY 16 /* probe is on the function entry */
108 /* Has this kprobe gone ? */
109 static inline bool kprobe_gone(struct kprobe *p)
111 return p->flags & KPROBE_FLAG_GONE;
114 /* Is this kprobe disabled ? */
115 static inline bool kprobe_disabled(struct kprobe *p)
117 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
120 /* Is this kprobe really running optimized path ? */
121 static inline bool kprobe_optimized(struct kprobe *p)
123 return p->flags & KPROBE_FLAG_OPTIMIZED;
126 /* Is this kprobe uses ftrace ? */
127 static inline bool kprobe_ftrace(struct kprobe *p)
129 return p->flags & KPROBE_FLAG_FTRACE;
133 * Function-return probe -
135 * User needs to provide a handler function, and initialize maxactive.
136 * maxactive - The maximum number of instances of the probed function that
137 * can be active concurrently.
138 * nmissed - tracks the number of times the probed function's return was
139 * ignored, due to maxactive being too low.
142 struct kretprobe_holder {
143 struct kretprobe __rcu *rp;
149 kretprobe_handler_t handler;
150 kretprobe_handler_t entry_handler;
154 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
157 struct freelist_head freelist;
158 struct kretprobe_holder *rph;
162 #define KRETPROBE_MAX_DATA_SIZE 4096
164 struct kretprobe_instance {
165 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
166 struct rethook_node node;
169 struct freelist_node freelist;
172 struct llist_node llist;
173 struct kretprobe_holder *rph;
174 kprobe_opcode_t *ret_addr;
180 struct kretprobe_blackpoint {
185 struct kprobe_blacklist_entry {
186 struct list_head list;
187 unsigned long start_addr;
188 unsigned long end_addr;
191 #ifdef CONFIG_KPROBES
192 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
193 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
195 extern void kprobe_busy_begin(void);
196 extern void kprobe_busy_end(void);
198 #ifdef CONFIG_KRETPROBES
199 /* Check whether @p is used for implementing a trampoline. */
200 extern int arch_trampoline_kprobe(struct kprobe *p);
202 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
203 static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
205 /* rethook::data is non-changed field, so that you can access it freely. */
206 return (struct kretprobe *)ri->node.rethook->data;
208 static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
210 return ri->node.ret_addr;
213 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
214 struct pt_regs *regs);
215 void arch_kretprobe_fixup_return(struct pt_regs *regs,
216 kprobe_opcode_t *correct_ret_addr);
218 void __kretprobe_trampoline(void);
220 * Since some architecture uses structured function pointer,
221 * use dereference_function_descriptor() to get real function address.
223 static nokprobe_inline void *kretprobe_trampoline_addr(void)
225 return dereference_kernel_function_descriptor(__kretprobe_trampoline);
228 /* If the trampoline handler called from a kprobe, use this version */
229 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
230 void *frame_pointer);
232 static nokprobe_inline
233 unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
238 * Set a dummy kprobe for avoiding kretprobe recursion.
239 * Since kretprobe never runs in kprobe handler, no kprobe must
240 * be running at this point.
243 ret = __kretprobe_trampoline_handler(regs, frame_pointer);
249 static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
251 return rcu_dereference_check(ri->rph->rp, rcu_read_lock_any_held());
254 static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
256 return (unsigned long)ri->ret_addr;
258 #endif /* CONFIG_KRETPROBE_ON_RETHOOK */
260 #else /* !CONFIG_KRETPROBES */
261 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
262 struct pt_regs *regs)
265 static inline int arch_trampoline_kprobe(struct kprobe *p)
269 #endif /* CONFIG_KRETPROBES */
271 /* Markers of '_kprobe_blacklist' section */
272 extern unsigned long __start_kprobe_blacklist[];
273 extern unsigned long __stop_kprobe_blacklist[];
275 extern struct kretprobe_blackpoint kretprobe_blacklist[];
277 #ifdef CONFIG_KPROBES_SANITY_TEST
278 extern int init_test_probes(void);
279 #else /* !CONFIG_KPROBES_SANITY_TEST */
280 static inline int init_test_probes(void)
284 #endif /* CONFIG_KPROBES_SANITY_TEST */
286 extern int arch_prepare_kprobe(struct kprobe *p);
287 extern void arch_arm_kprobe(struct kprobe *p);
288 extern void arch_disarm_kprobe(struct kprobe *p);
289 extern int arch_init_kprobes(void);
290 extern void kprobes_inc_nmissed_count(struct kprobe *p);
291 extern bool arch_within_kprobe_blacklist(unsigned long addr);
292 extern int arch_populate_kprobe_blacklist(void);
293 extern int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
295 extern bool within_kprobe_blacklist(unsigned long addr);
296 extern int kprobe_add_ksym_blacklist(unsigned long entry);
297 extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
299 struct kprobe_insn_cache {
301 void *(*alloc)(void); /* allocate insn page */
302 void (*free)(void *); /* free insn page */
303 const char *sym; /* symbol for insn pages */
304 struct list_head pages; /* list of kprobe_insn_page */
305 size_t insn_size; /* size of instruction slot */
309 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
310 extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
311 extern void __free_insn_slot(struct kprobe_insn_cache *c,
312 kprobe_opcode_t *slot, int dirty);
313 /* sleep-less address checking routine */
314 extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
317 #define DEFINE_INSN_CACHE_OPS(__name) \
318 extern struct kprobe_insn_cache kprobe_##__name##_slots; \
320 static inline kprobe_opcode_t *get_##__name##_slot(void) \
322 return __get_insn_slot(&kprobe_##__name##_slots); \
325 static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
327 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
330 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
332 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
334 #define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
335 #define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
336 int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
337 unsigned long *value, char *type, char *sym);
338 #else /* !__ARCH_WANT_KPROBES_INSN_SLOT */
339 #define DEFINE_INSN_CACHE_OPS(__name) \
340 static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
346 DEFINE_INSN_CACHE_OPS(insn);
348 #ifdef CONFIG_OPTPROBES
350 * Internal structure for direct jump optimized probe
352 struct optimized_kprobe {
354 struct list_head list; /* list for optimizing queue */
355 struct arch_optimized_insn optinsn;
358 /* Architecture dependent functions for direct jump optimization */
359 extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
360 extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
361 extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
362 struct kprobe *orig);
363 extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
364 extern void arch_optimize_kprobes(struct list_head *oplist);
365 extern void arch_unoptimize_kprobes(struct list_head *oplist,
366 struct list_head *done_list);
367 extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
368 extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
369 kprobe_opcode_t *addr);
371 extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
373 DEFINE_INSN_CACHE_OPS(optinsn);
375 extern void wait_for_kprobe_optimizer(void);
376 bool optprobe_queued_unopt(struct optimized_kprobe *op);
377 bool kprobe_disarmed(struct kprobe *p);
378 #else /* !CONFIG_OPTPROBES */
379 static inline void wait_for_kprobe_optimizer(void) { }
380 #endif /* CONFIG_OPTPROBES */
382 #ifdef CONFIG_KPROBES_ON_FTRACE
383 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
384 struct ftrace_ops *ops, struct ftrace_regs *fregs);
385 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
387 static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
391 #endif /* CONFIG_KPROBES_ON_FTRACE */
393 /* Get the kprobe at this addr (if any) - called with preemption disabled */
394 struct kprobe *get_kprobe(void *addr);
396 /* kprobe_running() will just return the current_kprobe on this CPU */
397 static inline struct kprobe *kprobe_running(void)
399 return __this_cpu_read(current_kprobe);
402 static inline void reset_current_kprobe(void)
404 __this_cpu_write(current_kprobe, NULL);
407 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
409 return this_cpu_ptr(&kprobe_ctlblk);
412 kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
413 kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry);
415 int register_kprobe(struct kprobe *p);
416 void unregister_kprobe(struct kprobe *p);
417 int register_kprobes(struct kprobe **kps, int num);
418 void unregister_kprobes(struct kprobe **kps, int num);
420 int register_kretprobe(struct kretprobe *rp);
421 void unregister_kretprobe(struct kretprobe *rp);
422 int register_kretprobes(struct kretprobe **rps, int num);
423 void unregister_kretprobes(struct kretprobe **rps, int num);
425 #if defined(CONFIG_KRETPROBE_ON_RETHOOK) || !defined(CONFIG_KRETPROBES)
426 #define kprobe_flush_task(tk) do {} while (0)
428 void kprobe_flush_task(struct task_struct *tk);
431 void kprobe_free_init_mem(void);
433 int disable_kprobe(struct kprobe *kp);
434 int enable_kprobe(struct kprobe *kp);
436 void dump_kprobe(struct kprobe *kp);
438 void *alloc_insn_page(void);
440 void *alloc_optinsn_page(void);
441 void free_optinsn_page(void *page);
443 int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
446 int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
447 char *type, char *sym);
448 #else /* !CONFIG_KPROBES: */
450 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
454 static inline struct kprobe *get_kprobe(void *addr)
458 static inline struct kprobe *kprobe_running(void)
462 #define kprobe_busy_begin() do {} while (0)
463 #define kprobe_busy_end() do {} while (0)
465 static inline int register_kprobe(struct kprobe *p)
469 static inline int register_kprobes(struct kprobe **kps, int num)
473 static inline void unregister_kprobe(struct kprobe *p)
476 static inline void unregister_kprobes(struct kprobe **kps, int num)
479 static inline int register_kretprobe(struct kretprobe *rp)
483 static inline int register_kretprobes(struct kretprobe **rps, int num)
487 static inline void unregister_kretprobe(struct kretprobe *rp)
490 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
493 static inline void kprobe_flush_task(struct task_struct *tk)
496 static inline void kprobe_free_init_mem(void)
499 static inline int disable_kprobe(struct kprobe *kp)
503 static inline int enable_kprobe(struct kprobe *kp)
508 static inline bool within_kprobe_blacklist(unsigned long addr)
512 static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
513 char *type, char *sym)
517 #endif /* CONFIG_KPROBES */
519 static inline int disable_kretprobe(struct kretprobe *rp)
521 return disable_kprobe(&rp->kp);
523 static inline int enable_kretprobe(struct kretprobe *rp)
525 return enable_kprobe(&rp->kp);
528 #ifndef CONFIG_KPROBES
529 static inline bool is_kprobe_insn_slot(unsigned long addr)
533 #endif /* !CONFIG_KPROBES */
535 #ifndef CONFIG_OPTPROBES
536 static inline bool is_kprobe_optinsn_slot(unsigned long addr)
540 #endif /* !CONFIG_OPTPROBES */
542 #ifdef CONFIG_KRETPROBES
543 #ifdef CONFIG_KRETPROBE_ON_RETHOOK
544 static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
546 return is_rethook_trampoline(addr);
549 static nokprobe_inline
550 unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
551 struct llist_node **cur)
553 return rethook_find_ret_addr(tsk, (unsigned long)fp, cur);
556 static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
558 return (void *)addr == kretprobe_trampoline_addr();
561 unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
562 struct llist_node **cur);
565 static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
570 static nokprobe_inline
571 unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
572 struct llist_node **cur)
578 /* Returns true if kprobes handled the fault */
579 static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
582 if (!IS_ENABLED(CONFIG_KPROBES))
587 * To be potentially processing a kprobe fault and to be allowed
588 * to call kprobe_running(), we have to be non-preemptible.
592 if (!kprobe_running())
594 return kprobe_fault_handler(regs, trap);
597 #endif /* _LINUX_KPROBES_H */