kprobes.h revision b18018126f422f5b706fd750373425e10e84b486 
1#ifndef _LINUX_KPROBES_H
2#define _LINUX_KPROBES_H
3/*
4 *  Kernel Probes (KProbes)
5 *  include/linux/kprobes.h
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 *
21 * Copyright (C) IBM Corporation, 2002, 2004
22 *
23 * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
24 *		Probes initial implementation ( includes suggestions from
25 *		Rusty Russell).
26 * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 *		interface to access function arguments.
28 * 2005-May	Hien Nguyen <hien@us.ibm.com> and Jim Keniston
29 *		<jkenisto@us.ibm.com>  and Prasanna S Panchamukhi
30 *		<prasanna@in.ibm.com> added function-return probes.
31 */
32#include <linux/linkage.h>
33#include <linux/list.h>
34#include <linux/notifier.h>
35#include <linux/smp.h>
36#include <linux/percpu.h>
37#include <linux/spinlock.h>
38#include <linux/rcupdate.h>
39#include <linux/mutex.h>
40
41#ifdef CONFIG_KPROBES
42#include <asm/kprobes.h>
43
44/* kprobe_status settings */
45#define KPROBE_HIT_ACTIVE	0x00000001
46#define KPROBE_HIT_SS		0x00000002
47#define KPROBE_REENTER		0x00000004
48#define KPROBE_HIT_SSDONE	0x00000008
49
50/* Attach to insert probes on any functions which should be ignored*/
51#define __kprobes	__attribute__((__section__(".kprobes.text"))) notrace
52#else /* CONFIG_KPROBES */
53typedef int kprobe_opcode_t;
54struct arch_specific_insn {
55	int dummy;
56};
57#define __kprobes	notrace
58#endif /* CONFIG_KPROBES */
59
60struct kprobe;
61struct pt_regs;
62struct kretprobe;
63struct kretprobe_instance;
64typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
65typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
66typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
67				       unsigned long flags);
68typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
69				       int trapnr);
70typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
71				    struct pt_regs *);
72
73struct kprobe {
74	struct hlist_node hlist;
75
76	/* list of kprobes for multi-handler support */
77	struct list_head list;
78
79	/*count the number of times this probe was temporarily disarmed */
80	unsigned long nmissed;
81
82	/* location of the probe point */
83	kprobe_opcode_t *addr;
84
85	/* Allow user to indicate symbol name of the probe point */
86	const char *symbol_name;
87
88	/* Offset into the symbol */
89	unsigned int offset;
90
91	/* Called before addr is executed. */
92	kprobe_pre_handler_t pre_handler;
93
94	/* Called after addr is executed, unless... */
95	kprobe_post_handler_t post_handler;
96
97	/* ... called if executing addr causes a fault (eg. page fault).
98	 * Return 1 if it handled fault, otherwise kernel will see it. */
99	kprobe_fault_handler_t fault_handler;
100
101	/* ... called if breakpoint trap occurs in probe handler.
102	 * Return 1 if it handled break, otherwise kernel will see it. */
103	kprobe_break_handler_t break_handler;
104
105	/* Saved opcode (which has been replaced with breakpoint) */
106	kprobe_opcode_t opcode;
107
108	/* copy of the original instruction */
109	struct arch_specific_insn ainsn;
110
111	/* Indicates various status flags.  Protected by kprobe_mutex. */
112	u32 flags;
113};
114
115/* Kprobe status flags */
116#define KPROBE_FLAG_GONE	1 /* breakpoint has already gone */
117
118static inline int kprobe_gone(struct kprobe *p)
119{
120	return p->flags & KPROBE_FLAG_GONE;
121}
122
123/*
124 * Special probe type that uses setjmp-longjmp type tricks to resume
125 * execution at a specified entry with a matching prototype corresponding
126 * to the probed function - a trick to enable arguments to become
127 * accessible seamlessly by probe handling logic.
128 * Note:
129 * Because of the way compilers allocate stack space for local variables
130 * etc upfront, regardless of sub-scopes within a function, this mirroring
131 * principle currently works only for probes placed on function entry points.
132 */
133struct jprobe {
134	struct kprobe kp;
135	void *entry;	/* probe handling code to jump to */
136};
137
138/* For backward compatibility with old code using JPROBE_ENTRY() */
139#define JPROBE_ENTRY(handler)	(handler)
140
141/*
142 * Function-return probe -
143 * Note:
144 * User needs to provide a handler function, and initialize maxactive.
145 * maxactive - The maximum number of instances of the probed function that
146 * can be active concurrently.
147 * nmissed - tracks the number of times the probed function's return was
148 * ignored, due to maxactive being too low.
149 *
150 */
151struct kretprobe {
152	struct kprobe kp;
153	kretprobe_handler_t handler;
154	kretprobe_handler_t entry_handler;
155	int maxactive;
156	int nmissed;
157	size_t data_size;
158	struct hlist_head free_instances;
159	spinlock_t lock;
160};
161
162struct kretprobe_instance {
163	struct hlist_node hlist;
164	struct kretprobe *rp;
165	kprobe_opcode_t *ret_addr;
166	struct task_struct *task;
167	char data[0];
168};
169
170struct kretprobe_blackpoint {
171	const char *name;
172	void *addr;
173};
174
175struct kprobe_blackpoint {
176	const char *name;
177	unsigned long start_addr;
178	unsigned long range;
179};
180
181#ifdef CONFIG_KPROBES
182DECLARE_PER_CPU(struct kprobe *, current_kprobe);
183DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
184
185/*
186 * For #ifdef avoidance:
187 */
188static inline int kprobes_built_in(void)
189{
190	return 1;
191}
192
193#ifdef CONFIG_KRETPROBES
194extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
195				   struct pt_regs *regs);
196extern int arch_trampoline_kprobe(struct kprobe *p);
197#else /* CONFIG_KRETPROBES */
198static inline void arch_prepare_kretprobe(struct kretprobe *rp,
199					struct pt_regs *regs)
200{
201}
202static inline int arch_trampoline_kprobe(struct kprobe *p)
203{
204	return 0;
205}
206#endif /* CONFIG_KRETPROBES */
207
208extern struct kretprobe_blackpoint kretprobe_blacklist[];
209
210static inline void kretprobe_assert(struct kretprobe_instance *ri,
211	unsigned long orig_ret_address, unsigned long trampoline_address)
212{
213	if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
214		printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
215				ri->rp, ri->rp->kp.addr);
216		BUG();
217	}
218}
219
220#ifdef CONFIG_KPROBES_SANITY_TEST
221extern int init_test_probes(void);
222#else
223static inline int init_test_probes(void)
224{
225	return 0;
226}
227#endif /* CONFIG_KPROBES_SANITY_TEST */
228
229extern int arch_prepare_kprobe(struct kprobe *p);
230extern void arch_arm_kprobe(struct kprobe *p);
231extern void arch_disarm_kprobe(struct kprobe *p);
232extern int arch_init_kprobes(void);
233extern void show_registers(struct pt_regs *regs);
234extern kprobe_opcode_t *get_insn_slot(void);
235extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
236extern void kprobes_inc_nmissed_count(struct kprobe *p);
237
238/* Get the kprobe at this addr (if any) - called with preemption disabled */
239struct kprobe *get_kprobe(void *addr);
240void kretprobe_hash_lock(struct task_struct *tsk,
241			 struct hlist_head **head, unsigned long *flags);
242void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
243struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
244
245/* kprobe_running() will just return the current_kprobe on this CPU */
246static inline struct kprobe *kprobe_running(void)
247{
248	return (__get_cpu_var(current_kprobe));
249}
250
251static inline void reset_current_kprobe(void)
252{
253	__get_cpu_var(current_kprobe) = NULL;
254}
255
256static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
257{
258	return (&__get_cpu_var(kprobe_ctlblk));
259}
260
261int register_kprobe(struct kprobe *p);
262void unregister_kprobe(struct kprobe *p);
263int register_kprobes(struct kprobe **kps, int num);
264void unregister_kprobes(struct kprobe **kps, int num);
265int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
266int longjmp_break_handler(struct kprobe *, struct pt_regs *);
267int register_jprobe(struct jprobe *p);
268void unregister_jprobe(struct jprobe *p);
269int register_jprobes(struct jprobe **jps, int num);
270void unregister_jprobes(struct jprobe **jps, int num);
271void jprobe_return(void);
272unsigned long arch_deref_entry_point(void *);
273
274int register_kretprobe(struct kretprobe *rp);
275void unregister_kretprobe(struct kretprobe *rp);
276int register_kretprobes(struct kretprobe **rps, int num);
277void unregister_kretprobes(struct kretprobe **rps, int num);
278
279void kprobe_flush_task(struct task_struct *tk);
280void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
281
282#else /* !CONFIG_KPROBES: */
283
284static inline int kprobes_built_in(void)
285{
286	return 0;
287}
288static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
289{
290	return 0;
291}
292static inline struct kprobe *get_kprobe(void *addr)
293{
294	return NULL;
295}
296static inline struct kprobe *kprobe_running(void)
297{
298	return NULL;
299}
300static inline int register_kprobe(struct kprobe *p)
301{
302	return -ENOSYS;
303}
304static inline int register_kprobes(struct kprobe **kps, int num)
305{
306	return -ENOSYS;
307}
308static inline void unregister_kprobe(struct kprobe *p)
309{
310}
311static inline void unregister_kprobes(struct kprobe **kps, int num)
312{
313}
314static inline int register_jprobe(struct jprobe *p)
315{
316	return -ENOSYS;
317}
318static inline int register_jprobes(struct jprobe **jps, int num)
319{
320	return -ENOSYS;
321}
322static inline void unregister_jprobe(struct jprobe *p)
323{
324}
325static inline void unregister_jprobes(struct jprobe **jps, int num)
326{
327}
328static inline void jprobe_return(void)
329{
330}
331static inline int register_kretprobe(struct kretprobe *rp)
332{
333	return -ENOSYS;
334}
335static inline int register_kretprobes(struct kretprobe **rps, int num)
336{
337	return -ENOSYS;
338}
339static inline void unregister_kretprobe(struct kretprobe *rp)
340{
341}
342static inline void unregister_kretprobes(struct kretprobe **rps, int num)
343{
344}
345static inline void kprobe_flush_task(struct task_struct *tk)
346{
347}
348#endif /* CONFIG_KPROBES */
349#endif /* _LINUX_KPROBES_H */
350