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1da177e4
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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.
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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.
1da177e4 31 */
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32#include <linux/list.h>
33#include <linux/notifier.h>
34#include <linux/smp.h>
e6584523 35#include <linux/percpu.h>
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36#include <linux/spinlock.h>
37#include <linux/rcupdate.h>
7a7d1cf9 38#include <linux/mutex.h>
b94cce92 39
00d7c05a 40#ifdef CONFIG_KPROBES
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41#include <asm/kprobes.h>
42
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43/* 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
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49/* Attach to insert probes on any functions which should be ignored*/
50#define __kprobes __attribute__((__section__(".kprobes.text")))
51
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52struct kprobe;
53struct pt_regs;
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54struct kretprobe;
55struct kretprobe_instance;
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56typedef 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);
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62typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
63 struct pt_regs *);
64
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65struct kprobe {
66 struct hlist_node hlist;
67
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68 /* list of kprobes for multi-handler support */
69 struct list_head list;
70
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71 /* Indicates that the corresponding module has been ref counted */
72 unsigned int mod_refcounted;
73
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74 /*count the number of times this probe was temporarily disarmed */
75 unsigned long nmissed;
76
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77 /* location of the probe point */
78 kprobe_opcode_t *addr;
79
3a872d89 80 /* Allow user to indicate symbol name of the probe point */
9b3af29b 81 const char *symbol_name;
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82
83 /* Offset into the symbol */
84 unsigned int offset;
85
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86 /* 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;
81eae375 119 void *entry; /* probe handling code to jump to */
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120};
121
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122/* For backward compatibility with old code using JPROBE_ENTRY() */
123#define JPROBE_ENTRY(handler) (handler)
124
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125DECLARE_PER_CPU(struct kprobe *, current_kprobe);
126DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
127
9edddaa2 128#ifdef CONFIG_KRETPROBES
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129extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
130 struct pt_regs *regs);
bf8f6e5b 131extern int arch_trampoline_kprobe(struct kprobe *p);
9edddaa2 132#else /* CONFIG_KRETPROBES */
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133static inline void arch_prepare_kretprobe(struct kretprobe *rp,
134 struct pt_regs *regs)
135{
136}
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137static inline int arch_trampoline_kprobe(struct kprobe *p)
138{
139 return 0;
140}
9edddaa2 141#endif /* CONFIG_KRETPROBES */
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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;
f47cd9b5 155 kretprobe_handler_t entry_handler;
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156 int maxactive;
157 int nmissed;
f47cd9b5 158 size_t data_size;
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159 struct hlist_head free_instances;
160 struct hlist_head used_instances;
161};
162
163struct kretprobe_instance {
164 struct hlist_node uflist; /* either on free list or used list */
165 struct hlist_node hlist;
166 struct kretprobe *rp;
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167 kprobe_opcode_t *ret_addr;
168 struct task_struct *task;
f47cd9b5 169 char data[0];
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170};
171
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172struct kretprobe_blackpoint {
173 const char *name;
174 void *addr;
175};
176extern struct kretprobe_blackpoint kretprobe_blacklist[];
177
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178static inline void kretprobe_assert(struct kretprobe_instance *ri,
179 unsigned long orig_ret_address, unsigned long trampoline_address)
180{
181 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
182 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
183 ri->rp, ri->rp->kp.addr);
184 BUG();
185 }
186}
187
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188#ifdef CONFIG_KPROBES_SANITY_TEST
189extern int init_test_probes(void);
190#else
191static inline int init_test_probes(void)
192{
193 return 0;
194}
195#endif /* CONFIG_KPROBES_SANITY_TEST */
196
3516a460 197extern spinlock_t kretprobe_lock;
7a7d1cf9 198extern struct mutex kprobe_mutex;
1da177e4 199extern int arch_prepare_kprobe(struct kprobe *p);
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200extern void arch_arm_kprobe(struct kprobe *p);
201extern void arch_disarm_kprobe(struct kprobe *p);
6772926b 202extern int arch_init_kprobes(void);
1da177e4 203extern void show_registers(struct pt_regs *regs);
9ec4b1f3 204extern kprobe_opcode_t *get_insn_slot(void);
b4c6c34a 205extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
bf8d5c52 206extern void kprobes_inc_nmissed_count(struct kprobe *p);
1da177e4 207
d217d545 208/* Get the kprobe at this addr (if any) - called with preemption disabled */
1da177e4 209struct kprobe *get_kprobe(void *addr);
b94cce92 210struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
1da177e4 211
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212/* kprobe_running() will just return the current_kprobe on this CPU */
213static inline struct kprobe *kprobe_running(void)
214{
215 return (__get_cpu_var(current_kprobe));
216}
217
218static inline void reset_current_kprobe(void)
219{
220 __get_cpu_var(current_kprobe) = NULL;
221}
222
223static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
224{
225 return (&__get_cpu_var(kprobe_ctlblk));
226}
227
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228int register_kprobe(struct kprobe *p);
229void unregister_kprobe(struct kprobe *p);
230int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
231int longjmp_break_handler(struct kprobe *, struct pt_regs *);
232int register_jprobe(struct jprobe *p);
233void unregister_jprobe(struct jprobe *p);
234void jprobe_return(void);
3d7e3382 235unsigned long arch_deref_entry_point(void *);
1da177e4 236
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237int register_kretprobe(struct kretprobe *rp);
238void unregister_kretprobe(struct kretprobe *rp);
239
b94cce92 240void kprobe_flush_task(struct task_struct *tk);
99219a3f 241void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
8c1c9356 242
b94cce92 243#else /* CONFIG_KPROBES */
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244
245#define __kprobes /**/
246struct jprobe;
247struct kretprobe;
248
e6584523 249static inline struct kprobe *kprobe_running(void)
1da177e4 250{
e6584523 251 return NULL;
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252}
253static inline int register_kprobe(struct kprobe *p)
254{
255 return -ENOSYS;
256}
257static inline void unregister_kprobe(struct kprobe *p)
258{
259}
260static inline int register_jprobe(struct jprobe *p)
261{
262 return -ENOSYS;
263}
264static inline void unregister_jprobe(struct jprobe *p)
265{
266}
267static inline void jprobe_return(void)
268{
269}
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270static inline int register_kretprobe(struct kretprobe *rp)
271{
272 return -ENOSYS;
273}
274static inline void unregister_kretprobe(struct kretprobe *rp)
275{
276}
277static inline void kprobe_flush_task(struct task_struct *tk)
278{
279}
280#endif /* CONFIG_KPROBES */
1da177e4 281#endif /* _LINUX_KPROBES_H */