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