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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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.
Hien Nguyenb94cce92005-06-23 00:09:19 -070028 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/list.h>
33#include <linux/notifier.h>
34#include <linux/smp.h>
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -080035#include <linux/percpu.h>
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -080036#include <linux/spinlock.h>
37#include <linux/rcupdate.h>
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -080038#include <linux/mutex.h>
Hien Nguyenb94cce92005-06-23 00:09:19 -070039
Keshavamurthy Anil S00d7c052005-12-12 00:37:33 -080040#ifdef CONFIG_KPROBES
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <asm/kprobes.h>
42
Prasanna S Panchamukhiea32c652005-06-23 00:09:36 -070043/* kprobe_status settings */
44#define KPROBE_HIT_ACTIVE 0x00000001
45#define KPROBE_HIT_SS 0x00000002
46#define KPROBE_REENTER 0x00000004
47#define KPROBE_HIT_SSDONE 0x00000008
48
Prasanna S Panchamukhid0aaff92005-09-06 15:19:26 -070049/* Attach to insert probes on any functions which should be ignored*/
50#define __kprobes __attribute__((__section__(".kprobes.text")))
51
Linus Torvalds1da177e2005-04-16 15:20:36 -070052struct kprobe;
53struct pt_regs;
Hien Nguyenb94cce92005-06-23 00:09:19 -070054struct kretprobe;
55struct kretprobe_instance;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
57typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
58typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
59 unsigned long flags);
60typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
61 int trapnr);
Hien Nguyenb94cce92005-06-23 00:09:19 -070062typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
63 struct pt_regs *);
64
Linus Torvalds1da177e2005-04-16 15:20:36 -070065struct kprobe {
66 struct hlist_node hlist;
67
Ananth N Mavinakayanahalli64f562c2005-05-05 16:15:42 -070068 /* list of kprobes for multi-handler support */
69 struct list_head list;
70
Keshavamurthy Anil Sdf019b12006-01-11 12:17:41 -080071 /* Indicates that the corresponding module has been ref counted */
72 unsigned int mod_refcounted;
73
Prasanna S Panchamukhiea32c652005-06-23 00:09:36 -070074 /*count the number of times this probe was temporarily disarmed */
75 unsigned long nmissed;
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 /* location of the probe point */
78 kprobe_opcode_t *addr;
79
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -070080 /* Allow user to indicate symbol name of the probe point */
Ananth N Mavinakayanahalli9b3af292007-05-08 00:26:23 -070081 const char *symbol_name;
Ananth N Mavinakayanahalli3a872d82006-10-02 02:17:30 -070082
83 /* Offset into the symbol */
84 unsigned int offset;
85
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 /* Called before addr is executed. */
87 kprobe_pre_handler_t pre_handler;
88
89 /* Called after addr is executed, unless... */
90 kprobe_post_handler_t post_handler;
91
92 /* ... called if executing addr causes a fault (eg. page fault).
93 * Return 1 if it handled fault, otherwise kernel will see it. */
94 kprobe_fault_handler_t fault_handler;
95
96 /* ... called if breakpoint trap occurs in probe handler.
97 * Return 1 if it handled break, otherwise kernel will see it. */
98 kprobe_break_handler_t break_handler;
99
100 /* Saved opcode (which has been replaced with breakpoint) */
101 kprobe_opcode_t opcode;
102
103 /* copy of the original instruction */
104 struct arch_specific_insn ainsn;
105};
106
107/*
108 * Special probe type that uses setjmp-longjmp type tricks to resume
109 * execution at a specified entry with a matching prototype corresponding
110 * to the probed function - a trick to enable arguments to become
111 * accessible seamlessly by probe handling logic.
112 * Note:
113 * Because of the way compilers allocate stack space for local variables
114 * etc upfront, regardless of sub-scopes within a function, this mirroring
115 * principle currently works only for probes placed on function entry points.
116 */
117struct jprobe {
118 struct kprobe kp;
Michael Ellerman81eae372007-07-19 01:48:09 -0700119 void *entry; /* probe handling code to jump to */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120};
121
Michael Ellerman9e367d82007-07-19 01:48:10 -0700122/* For backward compatibility with old code using JPROBE_ENTRY() */
123#define JPROBE_ENTRY(handler) (handler)
124
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800125DECLARE_PER_CPU(struct kprobe *, current_kprobe);
126DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
127
Hien Nguyenb94cce92005-06-23 00:09:19 -0700128#ifdef ARCH_SUPPORTS_KRETPROBES
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700129extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
130 struct pt_regs *regs);
Ananth N Mavinakayanahallibf8f6e52007-05-08 00:34:16 -0700131extern int arch_trampoline_kprobe(struct kprobe *p);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700132#else /* ARCH_SUPPORTS_KRETPROBES */
Hien Nguyenb94cce92005-06-23 00:09:19 -0700133static inline void arch_prepare_kretprobe(struct kretprobe *rp,
134 struct pt_regs *regs)
135{
136}
Ananth N Mavinakayanahallibf8f6e52007-05-08 00:34:16 -0700137static inline int arch_trampoline_kprobe(struct kprobe *p)
138{
139 return 0;
140}
Hien Nguyenb94cce92005-06-23 00:09:19 -0700141#endif /* ARCH_SUPPORTS_KRETPROBES */
142/*
143 * Function-return probe -
144 * Note:
145 * User needs to provide a handler function, and initialize maxactive.
146 * maxactive - The maximum number of instances of the probed function that
147 * can be active concurrently.
148 * nmissed - tracks the number of times the probed function's return was
149 * ignored, due to maxactive being too low.
150 *
151 */
152struct kretprobe {
153 struct kprobe kp;
154 kretprobe_handler_t handler;
155 int maxactive;
156 int nmissed;
157 struct hlist_head free_instances;
158 struct hlist_head used_instances;
159};
160
161struct kretprobe_instance {
162 struct hlist_node uflist; /* either on free list or used list */
163 struct hlist_node hlist;
164 struct kretprobe *rp;
Rusty Lynch802eae72005-06-27 15:17:08 -0700165 kprobe_opcode_t *ret_addr;
166 struct task_struct *task;
Hien Nguyenb94cce92005-06-23 00:09:19 -0700167};
168
Ananth N Mavinakayanahalli0f95b7f2007-05-08 00:28:27 -0700169static inline void kretprobe_assert(struct kretprobe_instance *ri,
170 unsigned long orig_ret_address, unsigned long trampoline_address)
171{
172 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
173 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
174 ri->rp, ri->rp->kp.addr);
175 BUG();
176 }
177}
178
Ananth N Mavinakayanahalli3516a462005-11-07 01:00:13 -0800179extern spinlock_t kretprobe_lock;
Ingo Molnar7a7d1cf2006-03-23 03:00:35 -0800180extern struct mutex kprobe_mutex;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181extern int arch_prepare_kprobe(struct kprobe *p);
Rusty Lynch7e1048b2005-06-23 00:09:25 -0700182extern void arch_arm_kprobe(struct kprobe *p);
183extern void arch_disarm_kprobe(struct kprobe *p);
Rusty Lynch67729262005-07-05 18:54:50 -0700184extern int arch_init_kprobes(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185extern void show_registers(struct pt_regs *regs);
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -0700186extern kprobe_opcode_t *get_insn_slot(void);
Masami Hiramatsub4c6c342006-12-06 20:38:11 -0800187extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
Keshavamurthy Anil Sbf8d5c52005-12-12 00:37:34 -0800188extern void kprobes_inc_nmissed_count(struct kprobe *p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800190/* Get the kprobe at this addr (if any) - called with preemption disabled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191struct kprobe *get_kprobe(void *addr);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700192struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800194/* kprobe_running() will just return the current_kprobe on this CPU */
195static inline struct kprobe *kprobe_running(void)
196{
197 return (__get_cpu_var(current_kprobe));
198}
199
200static inline void reset_current_kprobe(void)
201{
202 __get_cpu_var(current_kprobe) = NULL;
203}
204
205static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
206{
207 return (&__get_cpu_var(kprobe_ctlblk));
208}
209
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210int register_kprobe(struct kprobe *p);
211void unregister_kprobe(struct kprobe *p);
212int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
213int longjmp_break_handler(struct kprobe *, struct pt_regs *);
214int register_jprobe(struct jprobe *p);
215void unregister_jprobe(struct jprobe *p);
216void jprobe_return(void);
Michael Ellerman3d7e3382007-07-19 01:48:11 -0700217unsigned long arch_deref_entry_point(void *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
Hien Nguyenb94cce92005-06-23 00:09:19 -0700219int register_kretprobe(struct kretprobe *rp);
220void unregister_kretprobe(struct kretprobe *rp);
221
Hien Nguyenb94cce92005-06-23 00:09:19 -0700222void kprobe_flush_task(struct task_struct *tk);
bibo,mao99219a32006-10-02 02:17:35 -0700223void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
Hien Nguyenb94cce92005-06-23 00:09:19 -0700224#else /* CONFIG_KPROBES */
Keshavamurthy Anil S00d7c052005-12-12 00:37:33 -0800225
226#define __kprobes /**/
227struct jprobe;
228struct kretprobe;
229
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800230static inline struct kprobe *kprobe_running(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231{
Ananth N Mavinakayanahallie6584522005-11-07 01:00:07 -0800232 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233}
234static inline int register_kprobe(struct kprobe *p)
235{
236 return -ENOSYS;
237}
238static inline void unregister_kprobe(struct kprobe *p)
239{
240}
241static inline int register_jprobe(struct jprobe *p)
242{
243 return -ENOSYS;
244}
245static inline void unregister_jprobe(struct jprobe *p)
246{
247}
248static inline void jprobe_return(void)
249{
250}
Hien Nguyenb94cce92005-06-23 00:09:19 -0700251static inline int register_kretprobe(struct kretprobe *rp)
252{
253 return -ENOSYS;
254}
255static inline void unregister_kretprobe(struct kretprobe *rp)
256{
257}
258static inline void kprobe_flush_task(struct task_struct *tk)
259{
260}
261#endif /* CONFIG_KPROBES */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262#endif /* _LINUX_KPROBES_H */