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 */
53 typedef int kprobe_opcode_t;
54 struct arch_specific_insn {
55 int dummy;
56 };
57 #define __kprobes notrace
58 #endif /* CONFIG_KPROBES */
59
60 struct kprobe;
61 struct pt_regs;
62 struct kretprobe;
63 struct kretprobe_instance;
64 typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
65 typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
66 typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
67 unsigned long flags);
68 typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
69 int trapnr);
70 typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
71 struct pt_regs *);
72
73 struct 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
kprobe_gone(struct kprobe * p)118 static 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 */
133 struct 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 */
151 struct 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
162 struct 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
170 struct kretprobe_blackpoint {
171 const char *name;
172 void *addr;
173 };
174
175 struct kprobe_blackpoint {
176 const char *name;
177 unsigned long start_addr;
178 unsigned long range;
179 };
180
181 #ifdef CONFIG_KPROBES
182 DECLARE_PER_CPU(struct kprobe *, current_kprobe);
183 DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
184
185 #ifdef CONFIG_KRETPROBES
186 extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
187 struct pt_regs *regs);
188 extern int arch_trampoline_kprobe(struct kprobe *p);
189 #else /* CONFIG_KRETPROBES */
arch_prepare_kretprobe(struct kretprobe * rp,struct pt_regs * regs)190 static inline void arch_prepare_kretprobe(struct kretprobe *rp,
191 struct pt_regs *regs)
192 {
193 }
arch_trampoline_kprobe(struct kprobe * p)194 static inline int arch_trampoline_kprobe(struct kprobe *p)
195 {
196 return 0;
197 }
198 #endif /* CONFIG_KRETPROBES */
199
200 extern struct kretprobe_blackpoint kretprobe_blacklist[];
201
kretprobe_assert(struct kretprobe_instance * ri,unsigned long orig_ret_address,unsigned long trampoline_address)202 static inline void kretprobe_assert(struct kretprobe_instance *ri,
203 unsigned long orig_ret_address, unsigned long trampoline_address)
204 {
205 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
206 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
207 ri->rp, ri->rp->kp.addr);
208 BUG();
209 }
210 }
211
212 #ifdef CONFIG_KPROBES_SANITY_TEST
213 extern int init_test_probes(void);
214 #else
init_test_probes(void)215 static inline int init_test_probes(void)
216 {
217 return 0;
218 }
219 #endif /* CONFIG_KPROBES_SANITY_TEST */
220
221 extern int arch_prepare_kprobe(struct kprobe *p);
222 extern void arch_arm_kprobe(struct kprobe *p);
223 extern void arch_disarm_kprobe(struct kprobe *p);
224 extern int arch_init_kprobes(void);
225 extern void show_registers(struct pt_regs *regs);
226 extern kprobe_opcode_t *get_insn_slot(void);
227 extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
228 extern void kprobes_inc_nmissed_count(struct kprobe *p);
229
230 /* Get the kprobe at this addr (if any) - called with preemption disabled */
231 struct kprobe *get_kprobe(void *addr);
232 void kretprobe_hash_lock(struct task_struct *tsk,
233 struct hlist_head **head, unsigned long *flags);
234 void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
235 struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
236
237 /* kprobe_running() will just return the current_kprobe on this CPU */
kprobe_running(void)238 static inline struct kprobe *kprobe_running(void)
239 {
240 return (__get_cpu_var(current_kprobe));
241 }
242
reset_current_kprobe(void)243 static inline void reset_current_kprobe(void)
244 {
245 __get_cpu_var(current_kprobe) = NULL;
246 }
247
get_kprobe_ctlblk(void)248 static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
249 {
250 return (&__get_cpu_var(kprobe_ctlblk));
251 }
252
253 int register_kprobe(struct kprobe *p);
254 void unregister_kprobe(struct kprobe *p);
255 int register_kprobes(struct kprobe **kps, int num);
256 void unregister_kprobes(struct kprobe **kps, int num);
257 int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
258 int longjmp_break_handler(struct kprobe *, struct pt_regs *);
259 int register_jprobe(struct jprobe *p);
260 void unregister_jprobe(struct jprobe *p);
261 int register_jprobes(struct jprobe **jps, int num);
262 void unregister_jprobes(struct jprobe **jps, int num);
263 void jprobe_return(void);
264 unsigned long arch_deref_entry_point(void *);
265
266 int register_kretprobe(struct kretprobe *rp);
267 void unregister_kretprobe(struct kretprobe *rp);
268 int register_kretprobes(struct kretprobe **rps, int num);
269 void unregister_kretprobes(struct kretprobe **rps, int num);
270
271 void kprobe_flush_task(struct task_struct *tk);
272 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
273
274 #else /* CONFIG_KPROBES */
275
get_kprobe(void * addr)276 static inline struct kprobe *get_kprobe(void *addr)
277 {
278 return NULL;
279 }
kprobe_running(void)280 static inline struct kprobe *kprobe_running(void)
281 {
282 return NULL;
283 }
register_kprobe(struct kprobe * p)284 static inline int register_kprobe(struct kprobe *p)
285 {
286 return -ENOSYS;
287 }
register_kprobes(struct kprobe ** kps,int num)288 static inline int register_kprobes(struct kprobe **kps, int num)
289 {
290 return -ENOSYS;
291 }
unregister_kprobe(struct kprobe * p)292 static inline void unregister_kprobe(struct kprobe *p)
293 {
294 }
unregister_kprobes(struct kprobe ** kps,int num)295 static inline void unregister_kprobes(struct kprobe **kps, int num)
296 {
297 }
register_jprobe(struct jprobe * p)298 static inline int register_jprobe(struct jprobe *p)
299 {
300 return -ENOSYS;
301 }
register_jprobes(struct jprobe ** jps,int num)302 static inline int register_jprobes(struct jprobe **jps, int num)
303 {
304 return -ENOSYS;
305 }
unregister_jprobe(struct jprobe * p)306 static inline void unregister_jprobe(struct jprobe *p)
307 {
308 }
unregister_jprobes(struct jprobe ** jps,int num)309 static inline void unregister_jprobes(struct jprobe **jps, int num)
310 {
311 }
jprobe_return(void)312 static inline void jprobe_return(void)
313 {
314 }
register_kretprobe(struct kretprobe * rp)315 static inline int register_kretprobe(struct kretprobe *rp)
316 {
317 return -ENOSYS;
318 }
register_kretprobes(struct kretprobe ** rps,int num)319 static inline int register_kretprobes(struct kretprobe **rps, int num)
320 {
321 return -ENOSYS;
322 }
unregister_kretprobe(struct kretprobe * rp)323 static inline void unregister_kretprobe(struct kretprobe *rp)
324 {
325 }
unregister_kretprobes(struct kretprobe ** rps,int num)326 static inline void unregister_kretprobes(struct kretprobe **rps, int num)
327 {
328 }
kprobe_flush_task(struct task_struct * tk)329 static inline void kprobe_flush_task(struct task_struct *tk)
330 {
331 }
332 #endif /* CONFIG_KPROBES */
333 #endif /* _LINUX_KPROBES_H */
334