summaryrefslogtreecommitdiffstats
path: root/include/linux/kprobes.h
blob: 8f68490842481286446efc92a835ff38db1f1aac (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
#ifndef _LINUX_KPROBES_H
#define _LINUX_KPROBES_H
/*
 *  Kernel Probes (KProbes)
 *  include/linux/kprobes.h
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2002, 2004
 *
 * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
 *		Probes initial implementation ( includes suggestions from
 *		Rusty Russell).
 * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
 *		interface to access function arguments.
 * 2005-May	Hien Nguyen <hien@us.ibm.com> and Jim Keniston
 *		<jkenisto@us.ibm.com>  and Prasanna S Panchamukhi
 *		<prasanna@in.ibm.com> added function-return probes.
 */
#include <linux/compiler.h>	/* for __kprobes */
#include <linux/linkage.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#include <linux/bug.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>

#ifdef CONFIG_KPROBES
#include <asm/kprobes.h>

/* kprobe_status settings */
#define KPROBE_HIT_ACTIVE	0x00000001
#define KPROBE_HIT_SS		0x00000002
#define KPROBE_REENTER		0x00000004
#define KPROBE_HIT_SSDONE	0x00000008

#else /* CONFIG_KPROBES */
typedef int kprobe_opcode_t;
struct arch_specific_insn {
	int dummy;
};
#endif /* CONFIG_KPROBES */

struct kprobe;
struct pt_regs;
struct kretprobe;
struct kretprobe_instance;
typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
				       unsigned long flags);
typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
				       int trapnr);
typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
				    struct pt_regs *);

struct kprobe {
	struct hlist_node hlist;

	/* list of kprobes for multi-handler support */
	struct list_head list;

	/*count the number of times this probe was temporarily disarmed */
	unsigned long nmissed;

	/* location of the probe point */
	kprobe_opcode_t *addr;

	/* Allow user to indicate symbol name of the probe point */
	const char *symbol_name;

	/* Offset into the symbol */
	unsigned int offset;

	/* Called before addr is executed. */
	kprobe_pre_handler_t pre_handler;

	/* Called after addr is executed, unless... */
	kprobe_post_handler_t post_handler;

	/*
	 * ... called if executing addr causes a fault (eg. page fault).
	 * Return 1 if it handled fault, otherwise kernel will see it.
	 */
	kprobe_fault_handler_t fault_handler;

	/*
	 * ... called if breakpoint trap occurs in probe handler.
	 * Return 1 if it handled break, otherwise kernel will see it.
	 */
	kprobe_break_handler_t break_handler;

	/* Saved opcode (which has been replaced with breakpoint) */
	kprobe_opcode_t opcode;

	/* copy of the original instruction */
	struct arch_specific_insn ainsn;

	/*
	 * Indicates various status flags.
	 * Protected by kprobe_mutex after this kprobe is registered.
	 */
	u32 flags;
};

/* Kprobe status flags */
#define KPROBE_FLAG_GONE	1 /* breakpoint has already gone */
#define KPROBE_FLAG_DISABLED	2 /* probe is temporarily disabled */
#define KPROBE_FLAG_OPTIMIZED	4 /*
				   * probe is really optimized.
				   * NOTE:
				   * this flag is only for optimized_kprobe.
				   */
#define KPROBE_FLAG_FTRACE	8 /* probe is using ftrace */

/* Has this kprobe gone ? */
static inline int kprobe_gone(struct kprobe *p)
{
	return p->flags & KPROBE_FLAG_GONE;
}

/* Is this kprobe disabled ? */
static inline int kprobe_disabled(struct kprobe *p)
{
	return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
}

/* Is this kprobe really running optimized path ? */
static inline int kprobe_optimized(struct kprobe *p)
{
	return p->flags & KPROBE_FLAG_OPTIMIZED;
}

/* Is this kprobe uses ftrace ? */
static inline int kprobe_ftrace(struct kprobe *p)
{
	return p->flags & KPROBE_FLAG_FTRACE;
}

/*
 * Special probe type that uses setjmp-longjmp type tricks to resume
 * execution at a specified entry with a matching prototype corresponding
 * to the probed function - a trick to enable arguments to become
 * accessible seamlessly by probe handling logic.
 * Note:
 * Because of the way compilers allocate stack space for local variables
 * etc upfront, regardless of sub-scopes within a function, this mirroring
 * principle currently works only for probes placed on function entry points.
 */
struct jprobe {
	struct kprobe kp;
	void *entry;	/* probe handling code to jump to */
};

/* For backward compatibility with old code using JPROBE_ENTRY() */
#define JPROBE_ENTRY(handler)	(handler)

/*
 * Function-return probe -
 * Note:
 * User needs to provide a handler function, and initialize maxactive.
 * maxactive - The maximum number of instances of the probed function that
 * can be active concurrently.
 * nmissed - tracks the number of times the probed function's return was
 * ignored, due to maxactive being too low.
 *
 */
struct kretprobe {
	struct kprobe kp;
	kretprobe_handler_t handler;
	kretprobe_handler_t entry_handler;
	int maxactive;
	int nmissed;
	size_t data_size;
	struct hlist_head free_instances;
	raw_spinlock_t lock;
};

struct kretprobe_instance {
	struct hlist_node hlist;
	struct kretprobe *rp;
	kprobe_opcode_t *ret_addr;
	struct task_struct *task;
	char data[0];
};

struct kretprobe_blackpoint {
	const char *name;
	void *addr;
};

struct kprobe_blacklist_entry {
	struct list_head list;
	unsigned long start_addr;
	unsigned long end_addr;
};

#ifdef CONFIG_KPROBES
DECLARE_PER_CPU(struct kprobe *, current_kprobe);
DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

/*
 * For #ifdef avoidance:
 */
static inline int kprobes_built_in(void)
{
	return 1;
}

#ifdef CONFIG_KRETPROBES
extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
				   struct pt_regs *regs);
extern int arch_trampoline_kprobe(struct kprobe *p);
#else /* CONFIG_KRETPROBES */
static inline void arch_prepare_kretprobe(struct kretprobe *rp,
					struct pt_regs *regs)
{
}
static inline int arch_trampoline_kprobe(struct kprobe *p)
{
	return 0;
}
#endif /* CONFIG_KRETPROBES */

extern struct kretprobe_blackpoint kretprobe_blacklist[];

static inline void kretprobe_assert(struct kretprobe_instance *ri,
	unsigned long orig_ret_address, unsigned long trampoline_address)
{
	if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
		printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
				ri->rp, ri->rp->kp.addr);
		BUG();
	}
}

#ifdef CONFIG_KPROBES_SANITY_TEST
extern int init_test_probes(void);
#else
static inline int init_test_probes(void)
{
	return 0;
}
#endif /* CONFIG_KPROBES_SANITY_TEST */

extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
extern void show_registers(struct pt_regs *regs);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
extern bool arch_within_kprobe_blacklist(unsigned long addr);

extern bool within_kprobe_blacklist(unsigned long addr);

struct kprobe_insn_cache {
	struct mutex mutex;
	void *(*alloc)(void);	/* allocate insn page */
	void (*free)(void *);	/* free insn page */
	struct list_head pages; /* list of kprobe_insn_page */
	size_t insn_size;	/* size of instruction slot */
	int nr_garbage;
};

extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
extern void __free_insn_slot(struct kprobe_insn_cache *c,
			     kprobe_opcode_t *slot, int dirty);

#define DEFINE_INSN_CACHE_OPS(__name)					\
extern struct kprobe_insn_cache kprobe_##__name##_slots;		\
									\
static inline kprobe_opcode_t *get_##__name##_slot(void)		\
{									\
	return __get_insn_slot(&kprobe_##__name##_slots);		\
}									\
									\
static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
{									\
	__free_insn_slot(&kprobe_##__name##_slots, slot, dirty);	\
}									\

DEFINE_INSN_CACHE_OPS(insn);

#ifdef CONFIG_OPTPROBES
/*
 * Internal structure for direct jump optimized probe
 */
struct optimized_kprobe {
	struct kprobe kp;
	struct list_head list;	/* list for optimizing queue */
	struct arch_optimized_insn optinsn;
};

/* Architecture dependent functions for direct jump optimization */
extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op,
					 struct kprobe *orig);
extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
extern void arch_optimize_kprobes(struct list_head *oplist);
extern void arch_unoptimize_kprobes(struct list_head *oplist,
				    struct list_head *done_list);
extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
					unsigned long addr);

extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);

DEFINE_INSN_CACHE_OPS(optinsn);

#ifdef CONFIG_SYSCTL
extern int sysctl_kprobes_optimization;
extern int proc_kprobes_optimization_handler(struct ctl_table *table,
					     int write, void __user *buffer,
					     size_t *length, loff_t *ppos);
#endif

#endif /* CONFIG_OPTPROBES */
#ifdef CONFIG_KPROBES_ON_FTRACE
extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
				  struct ftrace_ops *ops, struct pt_regs *regs);
extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
#endif

int arch_check_ftrace_location(struct kprobe *p);

/* Get the kprobe at this addr (if any) - called with preemption disabled */
struct kprobe *get_kprobe(void *addr);
void kretprobe_hash_lock(struct task_struct *tsk,
			 struct hlist_head **head, unsigned long *flags);
void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);

/* kprobe_running() will just return the current_kprobe on this CPU */
static inline struct kprobe *kprobe_running(void)
{
	return (__this_cpu_read(current_kprobe));
}

static inline void reset_current_kprobe(void)
{
	__this_cpu_write(current_kprobe, NULL);
}

static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
{
	return this_cpu_ptr(&kprobe_ctlblk);
}

int register_kprobe(struct kprobe *p);
void unregister_kprobe(struct kprobe *p);
int register_kprobes(struct kprobe **kps, int num);
void unregister_kprobes(struct kprobe **kps, int num);
int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
int longjmp_break_handler(struct kprobe *, struct pt_regs *);
int register_jprobe(struct jprobe *p);
void unregister_jprobe(struct jprobe *p);
int register_jprobes(struct jprobe **jps, int num);
void unregister_jprobes(struct jprobe **jps, int num);
void jprobe_return(void);
unsigned long arch_deref_entry_point(void *);

int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
int register_kretprobes(struct kretprobe **rps, int num);
void unregister_kretprobes(struct kretprobe **rps, int num);

void kprobe_flush_task(struct task_struct *tk);
void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);

int disable_kprobe(struct kprobe *kp);
int enable_kprobe(struct kprobe *kp);

void dump_kprobe(struct kprobe *kp);

#else /* !CONFIG_KPROBES: */

static inline int kprobes_built_in(void)
{
	return 0;
}
static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
	return 0;
}
static inline struct kprobe *get_kprobe(void *addr)
{
	return NULL;
}
static inline struct kprobe *kprobe_running(void)
{
	return NULL;
}
static inline int register_kprobe(struct kprobe *p)
{
	return -ENOSYS;
}
static inline int register_kprobes(struct kprobe **kps, int num)
{
	return -ENOSYS;
}
static inline void unregister_kprobe(struct kprobe *p)
{
}
static inline void unregister_kprobes(struct kprobe **kps, int num)
{
}
static inline int register_jprobe(struct jprobe *p)
{
	return -ENOSYS;
}
static inline int register_jprobes(struct jprobe **jps, int num)
{
	return -ENOSYS;
}
static inline void unregister_jprobe(struct jprobe *p)
{
}
static inline void unregister_jprobes(struct jprobe **jps, int num)
{
}
static inline void jprobe_return(void)
{
}
static inline int register_kretprobe(struct kretprobe *rp)
{
	return -ENOSYS;
}
static inline int register_kretprobes(struct kretprobe **rps, int num)
{
	return -ENOSYS;
}
static inline void unregister_kretprobe(struct kretprobe *rp)
{
}
static inline void unregister_kretprobes(struct kretprobe **rps, int num)
{
}
static inline void kprobe_flush_task(struct task_struct *tk)
{
}
static inline int disable_kprobe(struct kprobe *kp)
{
	return -ENOSYS;
}
static inline int enable_kprobe(struct kprobe *kp)
{
	return -ENOSYS;
}
#endif /* CONFIG_KPROBES */
static inline int disable_kretprobe(struct kretprobe *rp)
{
	return disable_kprobe(&rp->kp);
}
static inline int enable_kretprobe(struct kretprobe *rp)
{
	return enable_kprobe(&rp->kp);
}
static inline int disable_jprobe(struct jprobe *jp)
{
	return disable_kprobe(&jp->kp);
}
static inline int enable_jprobe(struct jprobe *jp)
{
	return enable_kprobe(&jp->kp);
}

#ifdef CONFIG_KPROBES
/*
 * Blacklist ganerating macro. Specify functions which is not probed
 * by using this macro.
 */
#define __NOKPROBE_SYMBOL(fname)			\
static unsigned long __used				\
	__attribute__((section("_kprobe_blacklist")))	\
	_kbl_addr_##fname = (unsigned long)fname;
#define NOKPROBE_SYMBOL(fname)	__NOKPROBE_SYMBOL(fname)
#else
#define NOKPROBE_SYMBOL(fname)
#endif

#endif /* _LINUX_KPROBES_H */