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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.
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/bug.h>
37#include <linux/percpu.h>
38#include <linux/spinlock.h>
39#include <linux/rcupdate.h>
40#include <linux/mutex.h>
41
42#ifdef CONFIG_KPROBES
43#include <asm/kprobes.h>
44
45/* kprobe_status settings */
46#define KPROBE_HIT_ACTIVE 0x00000001
47#define KPROBE_HIT_SS 0x00000002
48#define KPROBE_REENTER 0x00000004
49#define KPROBE_HIT_SSDONE 0x00000008
50
51/* Attach to insert probes on any functions which should be ignored*/
52#define __kprobes __attribute__((__section__(".kprobes.text")))
53#else /* CONFIG_KPROBES */
54typedef int kprobe_opcode_t;
55struct arch_specific_insn {
56 int dummy;
57};
58#define __kprobes
59#endif /* CONFIG_KPROBES */
60
61struct kprobe;
62struct pt_regs;
63struct kretprobe;
64struct kretprobe_instance;
65typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
66typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
67typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
68 unsigned long flags);
69typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
70 int trapnr);
71typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
72 struct pt_regs *);
73
74struct kprobe {
75 struct hlist_node hlist;
76
77 /* list of kprobes for multi-handler support */
78 struct list_head list;
79
80 /*count the number of times this probe was temporarily disarmed */
81 unsigned long nmissed;
82
83 /* location of the probe point */
84 kprobe_opcode_t *addr;
85
86 /* Allow user to indicate symbol name of the probe point */
87 const char *symbol_name;
88
89 /* Offset into the symbol */
90 unsigned int offset;
91
92 /* Called before addr is executed. */
93 kprobe_pre_handler_t pre_handler;
94
95 /* Called after addr is executed, unless... */
96 kprobe_post_handler_t post_handler;
97
98 /*
99 * ... called if executing addr causes a fault (eg. page fault).
100 * Return 1 if it handled fault, otherwise kernel will see it.
101 */
102 kprobe_fault_handler_t fault_handler;
103
104 /*
105 * ... called if breakpoint trap occurs in probe handler.
106 * Return 1 if it handled break, otherwise kernel will see it.
107 */
108 kprobe_break_handler_t break_handler;
109
110 /* Saved opcode (which has been replaced with breakpoint) */
111 kprobe_opcode_t opcode;
112
113 /* copy of the original instruction */
114 struct arch_specific_insn ainsn;
115
116 /*
117 * Indicates various status flags.
118 * Protected by kprobe_mutex after this kprobe is registered.
119 */
120 u32 flags;
121};
122
123/* Kprobe status flags */
124#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
125#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
126#define KPROBE_FLAG_OPTIMIZED 4 /*
127 * probe is really optimized.
128 * NOTE:
129 * this flag is only for optimized_kprobe.
130 */
131
132/* Has this kprobe gone ? */
133static inline int kprobe_gone(struct kprobe *p)
134{
135 return p->flags & KPROBE_FLAG_GONE;
136}
137
138/* Is this kprobe disabled ? */
139static inline int kprobe_disabled(struct kprobe *p)
140{
141 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
142}
143
144/* Is this kprobe really running optimized path ? */
145static inline int kprobe_optimized(struct kprobe *p)
146{
147 return p->flags & KPROBE_FLAG_OPTIMIZED;
148}
149/*
150 * Special probe type that uses setjmp-longjmp type tricks to resume
151 * execution at a specified entry with a matching prototype corresponding
152 * to the probed function - a trick to enable arguments to become
153 * accessible seamlessly by probe handling logic.
154 * Note:
155 * Because of the way compilers allocate stack space for local variables
156 * etc upfront, regardless of sub-scopes within a function, this mirroring
157 * principle currently works only for probes placed on function entry points.
158 */
159struct jprobe {
160 struct kprobe kp;
161 void *entry; /* probe handling code to jump to */
162};
163
164/* For backward compatibility with old code using JPROBE_ENTRY() */
165#define JPROBE_ENTRY(handler) (handler)
166
167/*
168 * Function-return probe -
169 * Note:
170 * User needs to provide a handler function, and initialize maxactive.
171 * maxactive - The maximum number of instances of the probed function that
172 * can be active concurrently.
173 * nmissed - tracks the number of times the probed function's return was
174 * ignored, due to maxactive being too low.
175 *
176 */
177struct kretprobe {
178 struct kprobe kp;
179 kretprobe_handler_t handler;
180 kretprobe_handler_t entry_handler;
181 int maxactive;
182 int nmissed;
183 size_t data_size;
184 struct hlist_head free_instances;
185 raw_spinlock_t lock;
186};
187
188struct kretprobe_instance {
189 struct hlist_node hlist;
190 struct kretprobe *rp;
191 kprobe_opcode_t *ret_addr;
192 struct task_struct *task;
193 char data[0];
194};
195
196struct kretprobe_blackpoint {
197 const char *name;
198 void *addr;
199};
200
201struct kprobe_blackpoint {
202 const char *name;
203 unsigned long start_addr;
204 unsigned long range;
205};
206
207#ifdef CONFIG_KPROBES
208DECLARE_PER_CPU(struct kprobe *, current_kprobe);
209DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
210
211/*
212 * For #ifdef avoidance:
213 */
214static inline int kprobes_built_in(void)
215{
216 return 1;
217}
218
219#ifdef CONFIG_KRETPROBES
220extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
221 struct pt_regs *regs);
222extern int arch_trampoline_kprobe(struct kprobe *p);
223#else /* CONFIG_KRETPROBES */
224static inline void arch_prepare_kretprobe(struct kretprobe *rp,
225 struct pt_regs *regs)
226{
227}
228static inline int arch_trampoline_kprobe(struct kprobe *p)
229{
230 return 0;
231}
232#endif /* CONFIG_KRETPROBES */
233
234extern struct kretprobe_blackpoint kretprobe_blacklist[];
235
236static inline void kretprobe_assert(struct kretprobe_instance *ri,
237 unsigned long orig_ret_address, unsigned long trampoline_address)
238{
239 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
240 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
241 ri->rp, ri->rp->kp.addr);
242 BUG();
243 }
244}
245
246#ifdef CONFIG_KPROBES_SANITY_TEST
247extern int init_test_probes(void);
248#else
249static inline int init_test_probes(void)
250{
251 return 0;
252}
253#endif /* CONFIG_KPROBES_SANITY_TEST */
254
255extern int arch_prepare_kprobe(struct kprobe *p);
256extern void arch_arm_kprobe(struct kprobe *p);
257extern void arch_disarm_kprobe(struct kprobe *p);
258extern int arch_init_kprobes(void);
259extern void show_registers(struct pt_regs *regs);
260extern kprobe_opcode_t *get_insn_slot(void);
261extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
262extern void kprobes_inc_nmissed_count(struct kprobe *p);
263
264#ifdef CONFIG_OPTPROBES
265/*
266 * Internal structure for direct jump optimized probe
267 */
268struct optimized_kprobe {
269 struct kprobe kp;
270 struct list_head list; /* list for optimizing queue */
271 struct arch_optimized_insn optinsn;
272};
273
274/* Architecture dependent functions for direct jump optimization */
275extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
276extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
277extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
278extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
279extern void arch_optimize_kprobes(struct list_head *oplist);
280extern void arch_unoptimize_kprobes(struct list_head *oplist,
281 struct list_head *done_list);
282extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
283extern kprobe_opcode_t *get_optinsn_slot(void);
284extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
285extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
286 unsigned long addr);
287
288extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
289
290#ifdef CONFIG_SYSCTL
291extern int sysctl_kprobes_optimization;
292extern int proc_kprobes_optimization_handler(struct ctl_table *table,
293 int write, void __user *buffer,
294 size_t *length, loff_t *ppos);
295#endif
296
297#endif /* CONFIG_OPTPROBES */
298
299/* Get the kprobe at this addr (if any) - called with preemption disabled */
300struct kprobe *get_kprobe(void *addr);
301void kretprobe_hash_lock(struct task_struct *tsk,
302 struct hlist_head **head, unsigned long *flags);
303void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
304struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
305
306/* kprobe_running() will just return the current_kprobe on this CPU */
307static inline struct kprobe *kprobe_running(void)
308{
309 return (__this_cpu_read(current_kprobe));
310}
311
312static inline void reset_current_kprobe(void)
313{
314 __this_cpu_write(current_kprobe, NULL);
315}
316
317static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
318{
319 return (&__get_cpu_var(kprobe_ctlblk));
320}
321
322int register_kprobe(struct kprobe *p);
323void unregister_kprobe(struct kprobe *p);
324int register_kprobes(struct kprobe **kps, int num);
325void unregister_kprobes(struct kprobe **kps, int num);
326int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
327int longjmp_break_handler(struct kprobe *, struct pt_regs *);
328int register_jprobe(struct jprobe *p);
329void unregister_jprobe(struct jprobe *p);
330int register_jprobes(struct jprobe **jps, int num);
331void unregister_jprobes(struct jprobe **jps, int num);
332void jprobe_return(void);
333unsigned long arch_deref_entry_point(void *);
334
335int register_kretprobe(struct kretprobe *rp);
336void unregister_kretprobe(struct kretprobe *rp);
337int register_kretprobes(struct kretprobe **rps, int num);
338void unregister_kretprobes(struct kretprobe **rps, int num);
339
340void kprobe_flush_task(struct task_struct *tk);
341void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
342
343int disable_kprobe(struct kprobe *kp);
344int enable_kprobe(struct kprobe *kp);
345
346void dump_kprobe(struct kprobe *kp);
347
348#else /* !CONFIG_KPROBES: */
349
350static inline int kprobes_built_in(void)
351{
352 return 0;
353}
354static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
355{
356 return 0;
357}
358static inline struct kprobe *get_kprobe(void *addr)
359{
360 return NULL;
361}
362static inline struct kprobe *kprobe_running(void)
363{
364 return NULL;
365}
366static inline int register_kprobe(struct kprobe *p)
367{
368 return -ENOSYS;
369}
370static inline int register_kprobes(struct kprobe **kps, int num)
371{
372 return -ENOSYS;
373}
374static inline void unregister_kprobe(struct kprobe *p)
375{
376}
377static inline void unregister_kprobes(struct kprobe **kps, int num)
378{
379}
380static inline int register_jprobe(struct jprobe *p)
381{
382 return -ENOSYS;
383}
384static inline int register_jprobes(struct jprobe **jps, int num)
385{
386 return -ENOSYS;
387}
388static inline void unregister_jprobe(struct jprobe *p)
389{
390}
391static inline void unregister_jprobes(struct jprobe **jps, int num)
392{
393}
394static inline void jprobe_return(void)
395{
396}
397static inline int register_kretprobe(struct kretprobe *rp)
398{
399 return -ENOSYS;
400}
401static inline int register_kretprobes(struct kretprobe **rps, int num)
402{
403 return -ENOSYS;
404}
405static inline void unregister_kretprobe(struct kretprobe *rp)
406{
407}
408static inline void unregister_kretprobes(struct kretprobe **rps, int num)
409{
410}
411static inline void kprobe_flush_task(struct task_struct *tk)
412{
413}
414static inline int disable_kprobe(struct kprobe *kp)
415{
416 return -ENOSYS;
417}
418static inline int enable_kprobe(struct kprobe *kp)
419{
420 return -ENOSYS;
421}
422#endif /* CONFIG_KPROBES */
423static inline int disable_kretprobe(struct kretprobe *rp)
424{
425 return disable_kprobe(&rp->kp);
426}
427static inline int enable_kretprobe(struct kretprobe *rp)
428{
429 return enable_kprobe(&rp->kp);
430}
431static inline int disable_jprobe(struct jprobe *jp)
432{
433 return disable_kprobe(&jp->kp);
434}
435static inline int enable_jprobe(struct jprobe *jp)
436{
437 return enable_kprobe(&jp->kp);
438}
439
440#endif /* _LINUX_KPROBES_H */