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 *
7 * Copyright (C) IBM Corporation, 2002, 2004
8 *
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.
17 */
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>
32
33#ifdef CONFIG_KPROBES
34
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
40
41#else /* !CONFIG_KPROBES */
42#include <asm-generic/kprobes.h>
43typedef int kprobe_opcode_t;
44struct arch_specific_insn {
45 int dummy;
46};
47#endif /* CONFIG_KPROBES */
48
49struct kprobe;
50struct pt_regs;
51struct kretprobe;
52struct kretprobe_instance;
53typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
54typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
55 unsigned long flags);
56typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
57 struct pt_regs *);
58
59struct kprobe {
60 struct hlist_node hlist;
61
62 /* list of kprobes for multi-handler support */
63 struct list_head list;
64
65 /*count the number of times this probe was temporarily disarmed */
66 unsigned long nmissed;
67
68 /* location of the probe point */
69 kprobe_opcode_t *addr;
70
71 /* Allow user to indicate symbol name of the probe point */
72 const char *symbol_name;
73
74 /* Offset into the symbol */
75 unsigned int offset;
76
77 /* Called before addr is executed. */
78 kprobe_pre_handler_t pre_handler;
79
80 /* Called after addr is executed, unless... */
81 kprobe_post_handler_t post_handler;
82
83 /* Saved opcode (which has been replaced with breakpoint) */
84 kprobe_opcode_t opcode;
85
86 /* copy of the original instruction */
87 struct arch_specific_insn ainsn;
88
89 /*
90 * Indicates various status flags.
91 * Protected by kprobe_mutex after this kprobe is registered.
92 */
93 u32 flags;
94};
95
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.
103 */
104#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
105#define KPROBE_FLAG_ON_FUNC_ENTRY 16 /* probe is on the function entry */
106
107/* Has this kprobe gone ? */
108static inline bool kprobe_gone(struct kprobe *p)
109{
110 return p->flags & KPROBE_FLAG_GONE;
111}
112
113/* Is this kprobe disabled ? */
114static inline bool kprobe_disabled(struct kprobe *p)
115{
116 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
117}
118
119/* Is this kprobe really running optimized path ? */
120static inline bool kprobe_optimized(struct kprobe *p)
121{
122 return p->flags & KPROBE_FLAG_OPTIMIZED;
123}
124
125/* Is this kprobe uses ftrace ? */
126static inline bool kprobe_ftrace(struct kprobe *p)
127{
128 return p->flags & KPROBE_FLAG_FTRACE;
129}
130
131/*
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.
139 *
140 */
141struct kretprobe_holder {
142 struct kretprobe __rcu *rp;
143 struct objpool_head pool;
144};
145
146struct 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
158};
159
160#define KRETPROBE_MAX_DATA_SIZE 4096
161
162struct 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[];
173};
174
175struct kretprobe_blackpoint {
176 const char *name;
177 void *addr;
178};
179
180struct kprobe_blacklist_entry {
181 struct list_head list;
182 unsigned long start_addr;
183 unsigned long end_addr;
184};
185
186#ifdef CONFIG_KPROBES
187DECLARE_PER_CPU(struct kprobe *, current_kprobe);
188DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
189
190extern void kprobe_busy_begin(void);
191extern void kprobe_busy_end(void);
192
193#ifdef CONFIG_KRETPROBES
194/* Check whether @p is used for implementing a trampoline. */
195extern int arch_trampoline_kprobe(struct kprobe *p);
196
197#ifdef CONFIG_KRETPROBE_ON_RETHOOK
198static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
199{
200 /* rethook::data is non-changed field, so that you can access it freely. */
201 return (struct kretprobe *)ri->node.rethook->data;
202}
203static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
204{
205 return ri->node.ret_addr;
206}
207#else
208extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
209 struct pt_regs *regs);
210void arch_kretprobe_fixup_return(struct pt_regs *regs,
211 kprobe_opcode_t *correct_ret_addr);
212
213void __kretprobe_trampoline(void);
214/*
215 * Since some architecture uses structured function pointer,
216 * use dereference_function_descriptor() to get real function address.
217 */
218static nokprobe_inline void *kretprobe_trampoline_addr(void)
219{
220 return dereference_kernel_function_descriptor(__kretprobe_trampoline);
221}
222
223/* If the trampoline handler called from a kprobe, use this version */
224unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
225 void *frame_pointer);
226
227static nokprobe_inline
228unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
229 void *frame_pointer)
230{
231 unsigned long ret;
232 /*
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.
236 */
237 kprobe_busy_begin();
238 ret = __kretprobe_trampoline_handler(regs, frame_pointer);
239 kprobe_busy_end();
240
241 return ret;
242}
243
244static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance *ri)
245{
246 return rcu_dereference_check(ri->rph->rp, rcu_read_lock_any_held());
247}
248
249static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_instance *ri)
250{
251 return (unsigned long)ri->ret_addr;
252}
253#endif /* CONFIG_KRETPROBE_ON_RETHOOK */
254
255#else /* !CONFIG_KRETPROBES */
256static inline void arch_prepare_kretprobe(struct kretprobe *rp,
257 struct pt_regs *regs)
258{
259}
260static inline int arch_trampoline_kprobe(struct kprobe *p)
261{
262 return 0;
263}
264#endif /* CONFIG_KRETPROBES */
265
266/* Markers of '_kprobe_blacklist' section */
267extern unsigned long __start_kprobe_blacklist[];
268extern unsigned long __stop_kprobe_blacklist[];
269
270extern struct kretprobe_blackpoint kretprobe_blacklist[];
271
272extern int arch_prepare_kprobe(struct kprobe *p);
273extern void arch_arm_kprobe(struct kprobe *p);
274extern void arch_disarm_kprobe(struct kprobe *p);
275extern int arch_init_kprobes(void);
276extern void kprobes_inc_nmissed_count(struct kprobe *p);
277extern bool arch_within_kprobe_blacklist(unsigned long addr);
278extern int arch_populate_kprobe_blacklist(void);
279extern int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
280
281extern bool within_kprobe_blacklist(unsigned long addr);
282extern int kprobe_add_ksym_blacklist(unsigned long entry);
283extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
284
285struct 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;
293};
294
295#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
296extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
297extern void __free_insn_slot(struct kprobe_insn_cache *c,
298 kprobe_opcode_t *slot, int dirty);
299/* sleep-less address checking routine */
300extern bool __is_insn_slot_addr(struct kprobe_insn_cache *c,
301 unsigned long addr);
302
303#define DEFINE_INSN_CACHE_OPS(__name) \
304extern struct kprobe_insn_cache kprobe_##__name##_slots; \
305 \
306static inline kprobe_opcode_t *get_##__name##_slot(void) \
307{ \
308 return __get_insn_slot(&kprobe_##__name##_slots); \
309} \
310 \
311static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
312{ \
313 __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
314} \
315 \
316static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
317{ \
318 return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \
319}
320#define KPROBE_INSN_PAGE_SYM "kprobe_insn_page"
321#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
322int 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) \
326static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
327{ \
328 return 0; \
329}
330#endif
331
332DEFINE_INSN_CACHE_OPS(insn);
333
334#ifdef CONFIG_OPTPROBES
335/*
336 * Internal structure for direct jump optimized probe
337 */
338struct optimized_kprobe {
339 struct kprobe kp;
340 struct list_head list; /* list for optimizing queue */
341 struct arch_optimized_insn optinsn;
342};
343
344/* Architecture dependent functions for direct jump optimization */
345extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
346extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
347extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
348 struct kprobe *orig);
349extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
350extern void arch_optimize_kprobes(struct list_head *oplist);
351extern void arch_unoptimize_kprobes(struct list_head *oplist,
352 struct list_head *done_list);
353extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
354extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
355 kprobe_opcode_t *addr);
356
357extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
358
359DEFINE_INSN_CACHE_OPS(optinsn);
360
361extern void wait_for_kprobe_optimizer(void);
362bool optprobe_queued_unopt(struct optimized_kprobe *op);
363bool kprobe_disarmed(struct kprobe *p);
364#else /* !CONFIG_OPTPROBES */
365static inline void wait_for_kprobe_optimizer(void) { }
366#endif /* CONFIG_OPTPROBES */
367
368#ifdef CONFIG_KPROBES_ON_FTRACE
369extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
370 struct ftrace_ops *ops, struct ftrace_regs *fregs);
371extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
372/* Set when ftrace has been killed: kprobes on ftrace must be disabled for safety */
373extern bool kprobe_ftrace_disabled __read_mostly;
374extern void kprobe_ftrace_kill(void);
375#else
376static inline int arch_prepare_kprobe_ftrace(struct kprobe *p)
377{
378 return -EINVAL;
379}
380static inline void kprobe_ftrace_kill(void) {}
381#endif /* CONFIG_KPROBES_ON_FTRACE */
382
383/* Get the kprobe at this addr (if any) - called with preemption disabled */
384struct kprobe *get_kprobe(void *addr);
385
386/* kprobe_running() will just return the current_kprobe on this CPU */
387static inline struct kprobe *kprobe_running(void)
388{
389 return __this_cpu_read(current_kprobe);
390}
391
392static inline void reset_current_kprobe(void)
393{
394 __this_cpu_write(current_kprobe, NULL);
395}
396
397static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
398{
399 return this_cpu_ptr(&kprobe_ctlblk);
400}
401
402kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset);
403kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry);
404
405int register_kprobe(struct kprobe *p);
406void unregister_kprobe(struct kprobe *p);
407int register_kprobes(struct kprobe **kps, int num);
408void unregister_kprobes(struct kprobe **kps, int num);
409
410int register_kretprobe(struct kretprobe *rp);
411void unregister_kretprobe(struct kretprobe *rp);
412int register_kretprobes(struct kretprobe **rps, int num);
413void unregister_kretprobes(struct kretprobe **rps, int num);
414
415#if defined(CONFIG_KRETPROBE_ON_RETHOOK) || !defined(CONFIG_KRETPROBES)
416#define kprobe_flush_task(tk) do {} while (0)
417#else
418void kprobe_flush_task(struct task_struct *tk);
419#endif
420
421void kprobe_free_init_mem(void);
422
423int disable_kprobe(struct kprobe *kp);
424int enable_kprobe(struct kprobe *kp);
425
426void dump_kprobe(struct kprobe *kp);
427
428void *alloc_insn_page(void);
429
430void *alloc_optinsn_page(void);
431void free_optinsn_page(void *page);
432
433int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
434 char *sym);
435
436int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
437 char *type, char *sym);
438
439int kprobe_exceptions_notify(struct notifier_block *self,
440 unsigned long val, void *data);
441
442#else /* !CONFIG_KPROBES: */
443
444static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
445{
446 return 0;
447}
448static inline struct kprobe *get_kprobe(void *addr)
449{
450 return NULL;
451}
452static inline struct kprobe *kprobe_running(void)
453{
454 return NULL;
455}
456#define kprobe_busy_begin() do {} while (0)
457#define kprobe_busy_end() do {} while (0)
458
459static inline int register_kprobe(struct kprobe *p)
460{
461 return -EOPNOTSUPP;
462}
463static inline int register_kprobes(struct kprobe **kps, int num)
464{
465 return -EOPNOTSUPP;
466}
467static inline void unregister_kprobe(struct kprobe *p)
468{
469}
470static inline void unregister_kprobes(struct kprobe **kps, int num)
471{
472}
473static inline int register_kretprobe(struct kretprobe *rp)
474{
475 return -EOPNOTSUPP;
476}
477static inline int register_kretprobes(struct kretprobe **rps, int num)
478{
479 return -EOPNOTSUPP;
480}
481static inline void unregister_kretprobe(struct kretprobe *rp)
482{
483}
484static inline void unregister_kretprobes(struct kretprobe **rps, int num)
485{
486}
487static inline void kprobe_flush_task(struct task_struct *tk)
488{
489}
490static inline void kprobe_free_init_mem(void)
491{
492}
493static inline void kprobe_ftrace_kill(void)
494{
495}
496static inline int disable_kprobe(struct kprobe *kp)
497{
498 return -EOPNOTSUPP;
499}
500static inline int enable_kprobe(struct kprobe *kp)
501{
502 return -EOPNOTSUPP;
503}
504
505static inline bool within_kprobe_blacklist(unsigned long addr)
506{
507 return true;
508}
509static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
510 char *type, char *sym)
511{
512 return -ERANGE;
513}
514#endif /* CONFIG_KPROBES */
515
516static inline int disable_kretprobe(struct kretprobe *rp)
517{
518 return disable_kprobe(kp: &rp->kp);
519}
520static inline int enable_kretprobe(struct kretprobe *rp)
521{
522 return enable_kprobe(kp: &rp->kp);
523}
524
525#ifndef CONFIG_KPROBES
526static inline bool is_kprobe_insn_slot(unsigned long addr)
527{
528 return false;
529}
530#endif /* !CONFIG_KPROBES */
531
532#ifndef CONFIG_OPTPROBES
533static inline bool is_kprobe_optinsn_slot(unsigned long addr)
534{
535 return false;
536}
537#endif /* !CONFIG_OPTPROBES */
538
539#ifdef CONFIG_KRETPROBES
540#ifdef CONFIG_KRETPROBE_ON_RETHOOK
541static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
542{
543 return is_rethook_trampoline(addr);
544}
545
546static nokprobe_inline
547unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
548 struct llist_node **cur)
549{
550 return rethook_find_ret_addr(tsk, frame: (unsigned long)fp, cur);
551}
552#else
553static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
554{
555 return (void *)addr == kretprobe_trampoline_addr();
556}
557
558unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
559 struct llist_node **cur);
560#endif
561#else
562static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr)
563{
564 return false;
565}
566
567static nokprobe_inline
568unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
569 struct llist_node **cur)
570{
571 return 0;
572}
573#endif
574
575/* Returns true if kprobes handled the fault */
576static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
577 unsigned int trap)
578{
579 if (!IS_ENABLED(CONFIG_KPROBES))
580 return false;
581 if (user_mode(regs))
582 return false;
583 /*
584 * To be potentially processing a kprobe fault and to be allowed
585 * to call kprobe_running(), we have to be non-preemptible.
586 */
587 if (preemptible())
588 return false;
589 if (!kprobe_running())
590 return false;
591 return kprobe_fault_handler(regs, trapnr: trap);
592}
593
594#endif /* _LINUX_KPROBES_H */
595