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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#include <linux/ftrace.h>
42
43#ifdef CONFIG_KPROBES
44#include <asm/kprobes.h>
45
46/* kprobe_status settings */
47#define KPROBE_HIT_ACTIVE 0x00000001
48#define KPROBE_HIT_SS 0x00000002
49#define KPROBE_REENTER 0x00000004
50#define KPROBE_HIT_SSDONE 0x00000008
51
52/*
53 * If function tracer is enabled and the arch supports full
54 * passing of pt_regs to function tracing, then kprobes can
55 * optimize on top of function tracing.
56 */
57#if defined(CONFIG_FUNCTION_TRACER) && defined(ARCH_SUPPORTS_FTRACE_SAVE_REGS) \
58 && defined(ARCH_SUPPORTS_KPROBES_ON_FTRACE)
59# define KPROBES_CAN_USE_FTRACE
60#endif
61
62/* Attach to insert probes on any functions which should be ignored*/
63#define __kprobes __attribute__((__section__(".kprobes.text")))
64
65#else /* CONFIG_KPROBES */
66typedef int kprobe_opcode_t;
67struct arch_specific_insn {
68 int dummy;
69};
70#define __kprobes
71
72#endif /* CONFIG_KPROBES */
73
74struct kprobe;
75struct pt_regs;
76struct kretprobe;
77struct kretprobe_instance;
78typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *);
79typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *);
80typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *,
81 unsigned long flags);
82typedef int (*kprobe_fault_handler_t) (struct kprobe *, struct pt_regs *,
83 int trapnr);
84typedef int (*kretprobe_handler_t) (struct kretprobe_instance *,
85 struct pt_regs *);
86
87struct kprobe {
88 struct hlist_node hlist;
89
90 /* list of kprobes for multi-handler support */
91 struct list_head list;
92
93 /*count the number of times this probe was temporarily disarmed */
94 unsigned long nmissed;
95
96 /* location of the probe point */
97 kprobe_opcode_t *addr;
98
99 /* Allow user to indicate symbol name of the probe point */
100 const char *symbol_name;
101
102 /* Offset into the symbol */
103 unsigned int offset;
104
105 /* Called before addr is executed. */
106 kprobe_pre_handler_t pre_handler;
107
108 /* Called after addr is executed, unless... */
109 kprobe_post_handler_t post_handler;
110
111 /*
112 * ... called if executing addr causes a fault (eg. page fault).
113 * Return 1 if it handled fault, otherwise kernel will see it.
114 */
115 kprobe_fault_handler_t fault_handler;
116
117 /*
118 * ... called if breakpoint trap occurs in probe handler.
119 * Return 1 if it handled break, otherwise kernel will see it.
120 */
121 kprobe_break_handler_t break_handler;
122
123 /* Saved opcode (which has been replaced with breakpoint) */
124 kprobe_opcode_t opcode;
125
126 /* copy of the original instruction */
127 struct arch_specific_insn ainsn;
128
129 /*
130 * Indicates various status flags.
131 * Protected by kprobe_mutex after this kprobe is registered.
132 */
133 u32 flags;
134};
135
136/* Kprobe status flags */
137#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
138#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
139#define KPROBE_FLAG_OPTIMIZED 4 /*
140 * probe is really optimized.
141 * NOTE:
142 * this flag is only for optimized_kprobe.
143 */
144#define KPROBE_FLAG_FTRACE 8 /* probe is using ftrace */
145
146/* Has this kprobe gone ? */
147static inline int kprobe_gone(struct kprobe *p)
148{
149 return p->flags & KPROBE_FLAG_GONE;
150}
151
152/* Is this kprobe disabled ? */
153static inline int kprobe_disabled(struct kprobe *p)
154{
155 return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
156}
157
158/* Is this kprobe really running optimized path ? */
159static inline int kprobe_optimized(struct kprobe *p)
160{
161 return p->flags & KPROBE_FLAG_OPTIMIZED;
162}
163
164/* Is this kprobe uses ftrace ? */
165static inline int kprobe_ftrace(struct kprobe *p)
166{
167 return p->flags & KPROBE_FLAG_FTRACE;
168}
169
170/*
171 * Special probe type that uses setjmp-longjmp type tricks to resume
172 * execution at a specified entry with a matching prototype corresponding
173 * to the probed function - a trick to enable arguments to become
174 * accessible seamlessly by probe handling logic.
175 * Note:
176 * Because of the way compilers allocate stack space for local variables
177 * etc upfront, regardless of sub-scopes within a function, this mirroring
178 * principle currently works only for probes placed on function entry points.
179 */
180struct jprobe {
181 struct kprobe kp;
182 void *entry; /* probe handling code to jump to */
183};
184
185/* For backward compatibility with old code using JPROBE_ENTRY() */
186#define JPROBE_ENTRY(handler) (handler)
187
188/*
189 * Function-return probe -
190 * Note:
191 * User needs to provide a handler function, and initialize maxactive.
192 * maxactive - The maximum number of instances of the probed function that
193 * can be active concurrently.
194 * nmissed - tracks the number of times the probed function's return was
195 * ignored, due to maxactive being too low.
196 *
197 */
198struct kretprobe {
199 struct kprobe kp;
200 kretprobe_handler_t handler;
201 kretprobe_handler_t entry_handler;
202 int maxactive;
203 int nmissed;
204 size_t data_size;
205 struct hlist_head free_instances;
206 raw_spinlock_t lock;
207};
208
209struct kretprobe_instance {
210 struct hlist_node hlist;
211 struct kretprobe *rp;
212 kprobe_opcode_t *ret_addr;
213 struct task_struct *task;
214 char data[0];
215};
216
217struct kretprobe_blackpoint {
218 const char *name;
219 void *addr;
220};
221
222struct kprobe_blackpoint {
223 const char *name;
224 unsigned long start_addr;
225 unsigned long range;
226};
227
228#ifdef CONFIG_KPROBES
229DECLARE_PER_CPU(struct kprobe *, current_kprobe);
230DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
231
232/*
233 * For #ifdef avoidance:
234 */
235static inline int kprobes_built_in(void)
236{
237 return 1;
238}
239
240#ifdef CONFIG_KRETPROBES
241extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
242 struct pt_regs *regs);
243extern int arch_trampoline_kprobe(struct kprobe *p);
244#else /* CONFIG_KRETPROBES */
245static inline void arch_prepare_kretprobe(struct kretprobe *rp,
246 struct pt_regs *regs)
247{
248}
249static inline int arch_trampoline_kprobe(struct kprobe *p)
250{
251 return 0;
252}
253#endif /* CONFIG_KRETPROBES */
254
255extern struct kretprobe_blackpoint kretprobe_blacklist[];
256
257static inline void kretprobe_assert(struct kretprobe_instance *ri,
258 unsigned long orig_ret_address, unsigned long trampoline_address)
259{
260 if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
261 printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
262 ri->rp, ri->rp->kp.addr);
263 BUG();
264 }
265}
266
267#ifdef CONFIG_KPROBES_SANITY_TEST
268extern int init_test_probes(void);
269#else
270static inline int init_test_probes(void)
271{
272 return 0;
273}
274#endif /* CONFIG_KPROBES_SANITY_TEST */
275
276extern int arch_prepare_kprobe(struct kprobe *p);
277extern void arch_arm_kprobe(struct kprobe *p);
278extern void arch_disarm_kprobe(struct kprobe *p);
279extern int arch_init_kprobes(void);
280extern void show_registers(struct pt_regs *regs);
281extern kprobe_opcode_t *get_insn_slot(void);
282extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
283extern void kprobes_inc_nmissed_count(struct kprobe *p);
284
285#ifdef CONFIG_OPTPROBES
286/*
287 * Internal structure for direct jump optimized probe
288 */
289struct optimized_kprobe {
290 struct kprobe kp;
291 struct list_head list; /* list for optimizing queue */
292 struct arch_optimized_insn optinsn;
293};
294
295/* Architecture dependent functions for direct jump optimization */
296extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
297extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
298extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
299extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
300extern void arch_optimize_kprobes(struct list_head *oplist);
301extern void arch_unoptimize_kprobes(struct list_head *oplist,
302 struct list_head *done_list);
303extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
304extern kprobe_opcode_t *get_optinsn_slot(void);
305extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
306extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
307 unsigned long addr);
308
309extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
310
311#ifdef CONFIG_SYSCTL
312extern int sysctl_kprobes_optimization;
313extern int proc_kprobes_optimization_handler(struct ctl_table *table,
314 int write, void __user *buffer,
315 size_t *length, loff_t *ppos);
316#endif
317
318#endif /* CONFIG_OPTPROBES */
319#ifdef KPROBES_CAN_USE_FTRACE
320extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
321 struct ftrace_ops *ops, struct pt_regs *regs);
322extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
323#endif
324
325
326/* Get the kprobe at this addr (if any) - called with preemption disabled */
327struct kprobe *get_kprobe(void *addr);
328void kretprobe_hash_lock(struct task_struct *tsk,
329 struct hlist_head **head, unsigned long *flags);
330void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags);
331struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk);
332
333/* kprobe_running() will just return the current_kprobe on this CPU */
334static inline struct kprobe *kprobe_running(void)
335{
336 return (__this_cpu_read(current_kprobe));
337}
338
339static inline void reset_current_kprobe(void)
340{
341 __this_cpu_write(current_kprobe, NULL);
342}
343
344static inline struct kprobe_ctlblk *get_kprobe_ctlblk(void)
345{
346 return (&__get_cpu_var(kprobe_ctlblk));
347}
348
349int register_kprobe(struct kprobe *p);
350void unregister_kprobe(struct kprobe *p);
351int register_kprobes(struct kprobe **kps, int num);
352void unregister_kprobes(struct kprobe **kps, int num);
353int setjmp_pre_handler(struct kprobe *, struct pt_regs *);
354int longjmp_break_handler(struct kprobe *, struct pt_regs *);
355int register_jprobe(struct jprobe *p);
356void unregister_jprobe(struct jprobe *p);
357int register_jprobes(struct jprobe **jps, int num);
358void unregister_jprobes(struct jprobe **jps, int num);
359void jprobe_return(void);
360unsigned long arch_deref_entry_point(void *);
361
362int register_kretprobe(struct kretprobe *rp);
363void unregister_kretprobe(struct kretprobe *rp);
364int register_kretprobes(struct kretprobe **rps, int num);
365void unregister_kretprobes(struct kretprobe **rps, int num);
366
367void kprobe_flush_task(struct task_struct *tk);
368void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
369
370int disable_kprobe(struct kprobe *kp);
371int enable_kprobe(struct kprobe *kp);
372
373void dump_kprobe(struct kprobe *kp);
374
375#else /* !CONFIG_KPROBES: */
376
377static inline int kprobes_built_in(void)
378{
379 return 0;
380}
381static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
382{
383 return 0;
384}
385static inline struct kprobe *get_kprobe(void *addr)
386{
387 return NULL;
388}
389static inline struct kprobe *kprobe_running(void)
390{
391 return NULL;
392}
393static inline int register_kprobe(struct kprobe *p)
394{
395 return -ENOSYS;
396}
397static inline int register_kprobes(struct kprobe **kps, int num)
398{
399 return -ENOSYS;
400}
401static inline void unregister_kprobe(struct kprobe *p)
402{
403}
404static inline void unregister_kprobes(struct kprobe **kps, int num)
405{
406}
407static inline int register_jprobe(struct jprobe *p)
408{
409 return -ENOSYS;
410}
411static inline int register_jprobes(struct jprobe **jps, int num)
412{
413 return -ENOSYS;
414}
415static inline void unregister_jprobe(struct jprobe *p)
416{
417}
418static inline void unregister_jprobes(struct jprobe **jps, int num)
419{
420}
421static inline void jprobe_return(void)
422{
423}
424static inline int register_kretprobe(struct kretprobe *rp)
425{
426 return -ENOSYS;
427}
428static inline int register_kretprobes(struct kretprobe **rps, int num)
429{
430 return -ENOSYS;
431}
432static inline void unregister_kretprobe(struct kretprobe *rp)
433{
434}
435static inline void unregister_kretprobes(struct kretprobe **rps, int num)
436{
437}
438static inline void kprobe_flush_task(struct task_struct *tk)
439{
440}
441static inline int disable_kprobe(struct kprobe *kp)
442{
443 return -ENOSYS;
444}
445static inline int enable_kprobe(struct kprobe *kp)
446{
447 return -ENOSYS;
448}
449#endif /* CONFIG_KPROBES */
450static inline int disable_kretprobe(struct kretprobe *rp)
451{
452 return disable_kprobe(&rp->kp);
453}
454static inline int enable_kretprobe(struct kretprobe *rp)
455{
456 return enable_kprobe(&rp->kp);
457}
458static inline int disable_jprobe(struct jprobe *jp)
459{
460 return disable_kprobe(&jp->kp);
461}
462static inline int enable_jprobe(struct jprobe *jp)
463{
464 return enable_kprobe(&jp->kp);
465}
466
467#endif /* _LINUX_KPROBES_H */