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1 | /* | |
2 | * Kernel Probes (KProbes) | |
3 | * kernel/kprobes.c | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
18 | * | |
19 | * Copyright (C) IBM Corporation, 2002, 2004 | |
20 | * | |
21 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel | |
22 | * Probes initial implementation (includes suggestions from | |
23 | * Rusty Russell). | |
24 | * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with | |
25 | * hlists and exceptions notifier as suggested by Andi Kleen. | |
26 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes | |
27 | * interface to access function arguments. | |
28 | * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes | |
29 | * exceptions notifier to be first on the priority list. | |
30 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston | |
31 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi | |
32 | * <prasanna@in.ibm.com> added function-return probes. | |
33 | */ | |
34 | #include <linux/kprobes.h> | |
35 | #include <linux/hash.h> | |
36 | #include <linux/init.h> | |
37 | #include <linux/slab.h> | |
38 | #include <linux/stddef.h> | |
39 | #include <linux/module.h> | |
40 | #include <linux/moduleloader.h> | |
41 | #include <linux/kallsyms.h> | |
42 | #include <linux/freezer.h> | |
43 | #include <linux/seq_file.h> | |
44 | #include <linux/debugfs.h> | |
45 | #include <linux/kdebug.h> | |
46 | #include <linux/memory.h> | |
47 | ||
48 | #include <asm-generic/sections.h> | |
49 | #include <asm/cacheflush.h> | |
50 | #include <asm/errno.h> | |
51 | #include <asm/uaccess.h> | |
52 | ||
53 | #define KPROBE_HASH_BITS 6 | |
54 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
55 | ||
56 | ||
57 | /* | |
58 | * Some oddball architectures like 64bit powerpc have function descriptors | |
59 | * so this must be overridable. | |
60 | */ | |
61 | #ifndef kprobe_lookup_name | |
62 | #define kprobe_lookup_name(name, addr) \ | |
63 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) | |
64 | #endif | |
65 | ||
66 | static int kprobes_initialized; | |
67 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; | |
68 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; | |
69 | ||
70 | /* NOTE: change this value only with kprobe_mutex held */ | |
71 | static bool kprobe_enabled; | |
72 | ||
73 | static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ | |
74 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; | |
75 | static struct { | |
76 | spinlock_t lock ____cacheline_aligned_in_smp; | |
77 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; | |
78 | ||
79 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) | |
80 | { | |
81 | return &(kretprobe_table_locks[hash].lock); | |
82 | } | |
83 | ||
84 | /* | |
85 | * Normally, functions that we'd want to prohibit kprobes in, are marked | |
86 | * __kprobes. But, there are cases where such functions already belong to | |
87 | * a different section (__sched for preempt_schedule) | |
88 | * | |
89 | * For such cases, we now have a blacklist | |
90 | */ | |
91 | static struct kprobe_blackpoint kprobe_blacklist[] = { | |
92 | {"preempt_schedule",}, | |
93 | {NULL} /* Terminator */ | |
94 | }; | |
95 | ||
96 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT | |
97 | /* | |
98 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
99 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
100 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
101 | * is a recipe for disaster | |
102 | */ | |
103 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) | |
104 | ||
105 | struct kprobe_insn_page { | |
106 | struct hlist_node hlist; | |
107 | kprobe_opcode_t *insns; /* Page of instruction slots */ | |
108 | char slot_used[INSNS_PER_PAGE]; | |
109 | int nused; | |
110 | int ngarbage; | |
111 | }; | |
112 | ||
113 | enum kprobe_slot_state { | |
114 | SLOT_CLEAN = 0, | |
115 | SLOT_DIRTY = 1, | |
116 | SLOT_USED = 2, | |
117 | }; | |
118 | ||
119 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */ | |
120 | static struct hlist_head kprobe_insn_pages; | |
121 | static int kprobe_garbage_slots; | |
122 | static int collect_garbage_slots(void); | |
123 | ||
124 | static int __kprobes check_safety(void) | |
125 | { | |
126 | int ret = 0; | |
127 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_FREEZER) | |
128 | ret = freeze_processes(); | |
129 | if (ret == 0) { | |
130 | struct task_struct *p, *q; | |
131 | do_each_thread(p, q) { | |
132 | if (p != current && p->state == TASK_RUNNING && | |
133 | p->pid != 0) { | |
134 | printk("Check failed: %s is running\n",p->comm); | |
135 | ret = -1; | |
136 | goto loop_end; | |
137 | } | |
138 | } while_each_thread(p, q); | |
139 | } | |
140 | loop_end: | |
141 | thaw_processes(); | |
142 | #else | |
143 | synchronize_sched(); | |
144 | #endif | |
145 | return ret; | |
146 | } | |
147 | ||
148 | /** | |
149 | * __get_insn_slot() - Find a slot on an executable page for an instruction. | |
150 | * We allocate an executable page if there's no room on existing ones. | |
151 | */ | |
152 | static kprobe_opcode_t __kprobes *__get_insn_slot(void) | |
153 | { | |
154 | struct kprobe_insn_page *kip; | |
155 | struct hlist_node *pos; | |
156 | ||
157 | retry: | |
158 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { | |
159 | if (kip->nused < INSNS_PER_PAGE) { | |
160 | int i; | |
161 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
162 | if (kip->slot_used[i] == SLOT_CLEAN) { | |
163 | kip->slot_used[i] = SLOT_USED; | |
164 | kip->nused++; | |
165 | return kip->insns + (i * MAX_INSN_SIZE); | |
166 | } | |
167 | } | |
168 | /* Surprise! No unused slots. Fix kip->nused. */ | |
169 | kip->nused = INSNS_PER_PAGE; | |
170 | } | |
171 | } | |
172 | ||
173 | /* If there are any garbage slots, collect it and try again. */ | |
174 | if (kprobe_garbage_slots && collect_garbage_slots() == 0) { | |
175 | goto retry; | |
176 | } | |
177 | /* All out of space. Need to allocate a new page. Use slot 0. */ | |
178 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); | |
179 | if (!kip) | |
180 | return NULL; | |
181 | ||
182 | /* | |
183 | * Use module_alloc so this page is within +/- 2GB of where the | |
184 | * kernel image and loaded module images reside. This is required | |
185 | * so x86_64 can correctly handle the %rip-relative fixups. | |
186 | */ | |
187 | kip->insns = module_alloc(PAGE_SIZE); | |
188 | if (!kip->insns) { | |
189 | kfree(kip); | |
190 | return NULL; | |
191 | } | |
192 | INIT_HLIST_NODE(&kip->hlist); | |
193 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); | |
194 | memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE); | |
195 | kip->slot_used[0] = SLOT_USED; | |
196 | kip->nused = 1; | |
197 | kip->ngarbage = 0; | |
198 | return kip->insns; | |
199 | } | |
200 | ||
201 | kprobe_opcode_t __kprobes *get_insn_slot(void) | |
202 | { | |
203 | kprobe_opcode_t *ret; | |
204 | mutex_lock(&kprobe_insn_mutex); | |
205 | ret = __get_insn_slot(); | |
206 | mutex_unlock(&kprobe_insn_mutex); | |
207 | return ret; | |
208 | } | |
209 | ||
210 | /* Return 1 if all garbages are collected, otherwise 0. */ | |
211 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
212 | { | |
213 | kip->slot_used[idx] = SLOT_CLEAN; | |
214 | kip->nused--; | |
215 | if (kip->nused == 0) { | |
216 | /* | |
217 | * Page is no longer in use. Free it unless | |
218 | * it's the last one. We keep the last one | |
219 | * so as not to have to set it up again the | |
220 | * next time somebody inserts a probe. | |
221 | */ | |
222 | hlist_del(&kip->hlist); | |
223 | if (hlist_empty(&kprobe_insn_pages)) { | |
224 | INIT_HLIST_NODE(&kip->hlist); | |
225 | hlist_add_head(&kip->hlist, | |
226 | &kprobe_insn_pages); | |
227 | } else { | |
228 | module_free(NULL, kip->insns); | |
229 | kfree(kip); | |
230 | } | |
231 | return 1; | |
232 | } | |
233 | return 0; | |
234 | } | |
235 | ||
236 | static int __kprobes collect_garbage_slots(void) | |
237 | { | |
238 | struct kprobe_insn_page *kip; | |
239 | struct hlist_node *pos, *next; | |
240 | int safety; | |
241 | ||
242 | /* Ensure no-one is preepmted on the garbages */ | |
243 | mutex_unlock(&kprobe_insn_mutex); | |
244 | safety = check_safety(); | |
245 | mutex_lock(&kprobe_insn_mutex); | |
246 | if (safety != 0) | |
247 | return -EAGAIN; | |
248 | ||
249 | hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { | |
250 | int i; | |
251 | if (kip->ngarbage == 0) | |
252 | continue; | |
253 | kip->ngarbage = 0; /* we will collect all garbages */ | |
254 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
255 | if (kip->slot_used[i] == SLOT_DIRTY && | |
256 | collect_one_slot(kip, i)) | |
257 | break; | |
258 | } | |
259 | } | |
260 | kprobe_garbage_slots = 0; | |
261 | return 0; | |
262 | } | |
263 | ||
264 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) | |
265 | { | |
266 | struct kprobe_insn_page *kip; | |
267 | struct hlist_node *pos; | |
268 | ||
269 | mutex_lock(&kprobe_insn_mutex); | |
270 | hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { | |
271 | if (kip->insns <= slot && | |
272 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
273 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
274 | if (dirty) { | |
275 | kip->slot_used[i] = SLOT_DIRTY; | |
276 | kip->ngarbage++; | |
277 | } else { | |
278 | collect_one_slot(kip, i); | |
279 | } | |
280 | break; | |
281 | } | |
282 | } | |
283 | ||
284 | if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) | |
285 | collect_garbage_slots(); | |
286 | ||
287 | mutex_unlock(&kprobe_insn_mutex); | |
288 | } | |
289 | #endif | |
290 | ||
291 | /* We have preemption disabled.. so it is safe to use __ versions */ | |
292 | static inline void set_kprobe_instance(struct kprobe *kp) | |
293 | { | |
294 | __get_cpu_var(kprobe_instance) = kp; | |
295 | } | |
296 | ||
297 | static inline void reset_kprobe_instance(void) | |
298 | { | |
299 | __get_cpu_var(kprobe_instance) = NULL; | |
300 | } | |
301 | ||
302 | /* | |
303 | * This routine is called either: | |
304 | * - under the kprobe_mutex - during kprobe_[un]register() | |
305 | * OR | |
306 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c | |
307 | */ | |
308 | struct kprobe __kprobes *get_kprobe(void *addr) | |
309 | { | |
310 | struct hlist_head *head; | |
311 | struct hlist_node *node; | |
312 | struct kprobe *p; | |
313 | ||
314 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
315 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
316 | if (p->addr == addr) | |
317 | return p; | |
318 | } | |
319 | return NULL; | |
320 | } | |
321 | ||
322 | /* | |
323 | * Aggregate handlers for multiple kprobes support - these handlers | |
324 | * take care of invoking the individual kprobe handlers on p->list | |
325 | */ | |
326 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
327 | { | |
328 | struct kprobe *kp; | |
329 | ||
330 | list_for_each_entry_rcu(kp, &p->list, list) { | |
331 | if (kp->pre_handler && !kprobe_gone(kp)) { | |
332 | set_kprobe_instance(kp); | |
333 | if (kp->pre_handler(kp, regs)) | |
334 | return 1; | |
335 | } | |
336 | reset_kprobe_instance(); | |
337 | } | |
338 | return 0; | |
339 | } | |
340 | ||
341 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, | |
342 | unsigned long flags) | |
343 | { | |
344 | struct kprobe *kp; | |
345 | ||
346 | list_for_each_entry_rcu(kp, &p->list, list) { | |
347 | if (kp->post_handler && !kprobe_gone(kp)) { | |
348 | set_kprobe_instance(kp); | |
349 | kp->post_handler(kp, regs, flags); | |
350 | reset_kprobe_instance(); | |
351 | } | |
352 | } | |
353 | } | |
354 | ||
355 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, | |
356 | int trapnr) | |
357 | { | |
358 | struct kprobe *cur = __get_cpu_var(kprobe_instance); | |
359 | ||
360 | /* | |
361 | * if we faulted "during" the execution of a user specified | |
362 | * probe handler, invoke just that probe's fault handler | |
363 | */ | |
364 | if (cur && cur->fault_handler) { | |
365 | if (cur->fault_handler(cur, regs, trapnr)) | |
366 | return 1; | |
367 | } | |
368 | return 0; | |
369 | } | |
370 | ||
371 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) | |
372 | { | |
373 | struct kprobe *cur = __get_cpu_var(kprobe_instance); | |
374 | int ret = 0; | |
375 | ||
376 | if (cur && cur->break_handler) { | |
377 | if (cur->break_handler(cur, regs)) | |
378 | ret = 1; | |
379 | } | |
380 | reset_kprobe_instance(); | |
381 | return ret; | |
382 | } | |
383 | ||
384 | /* Walks the list and increments nmissed count for multiprobe case */ | |
385 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
386 | { | |
387 | struct kprobe *kp; | |
388 | if (p->pre_handler != aggr_pre_handler) { | |
389 | p->nmissed++; | |
390 | } else { | |
391 | list_for_each_entry_rcu(kp, &p->list, list) | |
392 | kp->nmissed++; | |
393 | } | |
394 | return; | |
395 | } | |
396 | ||
397 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, | |
398 | struct hlist_head *head) | |
399 | { | |
400 | struct kretprobe *rp = ri->rp; | |
401 | ||
402 | /* remove rp inst off the rprobe_inst_table */ | |
403 | hlist_del(&ri->hlist); | |
404 | INIT_HLIST_NODE(&ri->hlist); | |
405 | if (likely(rp)) { | |
406 | spin_lock(&rp->lock); | |
407 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
408 | spin_unlock(&rp->lock); | |
409 | } else | |
410 | /* Unregistering */ | |
411 | hlist_add_head(&ri->hlist, head); | |
412 | } | |
413 | ||
414 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, | |
415 | struct hlist_head **head, unsigned long *flags) | |
416 | { | |
417 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
418 | spinlock_t *hlist_lock; | |
419 | ||
420 | *head = &kretprobe_inst_table[hash]; | |
421 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
422 | spin_lock_irqsave(hlist_lock, *flags); | |
423 | } | |
424 | ||
425 | static void __kprobes kretprobe_table_lock(unsigned long hash, | |
426 | unsigned long *flags) | |
427 | { | |
428 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
429 | spin_lock_irqsave(hlist_lock, *flags); | |
430 | } | |
431 | ||
432 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, | |
433 | unsigned long *flags) | |
434 | { | |
435 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
436 | spinlock_t *hlist_lock; | |
437 | ||
438 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
439 | spin_unlock_irqrestore(hlist_lock, *flags); | |
440 | } | |
441 | ||
442 | void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags) | |
443 | { | |
444 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
445 | spin_unlock_irqrestore(hlist_lock, *flags); | |
446 | } | |
447 | ||
448 | /* | |
449 | * This function is called from finish_task_switch when task tk becomes dead, | |
450 | * so that we can recycle any function-return probe instances associated | |
451 | * with this task. These left over instances represent probed functions | |
452 | * that have been called but will never return. | |
453 | */ | |
454 | void __kprobes kprobe_flush_task(struct task_struct *tk) | |
455 | { | |
456 | struct kretprobe_instance *ri; | |
457 | struct hlist_head *head, empty_rp; | |
458 | struct hlist_node *node, *tmp; | |
459 | unsigned long hash, flags = 0; | |
460 | ||
461 | if (unlikely(!kprobes_initialized)) | |
462 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
463 | return; | |
464 | ||
465 | hash = hash_ptr(tk, KPROBE_HASH_BITS); | |
466 | head = &kretprobe_inst_table[hash]; | |
467 | kretprobe_table_lock(hash, &flags); | |
468 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
469 | if (ri->task == tk) | |
470 | recycle_rp_inst(ri, &empty_rp); | |
471 | } | |
472 | kretprobe_table_unlock(hash, &flags); | |
473 | INIT_HLIST_HEAD(&empty_rp); | |
474 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { | |
475 | hlist_del(&ri->hlist); | |
476 | kfree(ri); | |
477 | } | |
478 | } | |
479 | ||
480 | static inline void free_rp_inst(struct kretprobe *rp) | |
481 | { | |
482 | struct kretprobe_instance *ri; | |
483 | struct hlist_node *pos, *next; | |
484 | ||
485 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { | |
486 | hlist_del(&ri->hlist); | |
487 | kfree(ri); | |
488 | } | |
489 | } | |
490 | ||
491 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) | |
492 | { | |
493 | unsigned long flags, hash; | |
494 | struct kretprobe_instance *ri; | |
495 | struct hlist_node *pos, *next; | |
496 | struct hlist_head *head; | |
497 | ||
498 | /* No race here */ | |
499 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { | |
500 | kretprobe_table_lock(hash, &flags); | |
501 | head = &kretprobe_inst_table[hash]; | |
502 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
503 | if (ri->rp == rp) | |
504 | ri->rp = NULL; | |
505 | } | |
506 | kretprobe_table_unlock(hash, &flags); | |
507 | } | |
508 | free_rp_inst(rp); | |
509 | } | |
510 | ||
511 | /* | |
512 | * Keep all fields in the kprobe consistent | |
513 | */ | |
514 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
515 | { | |
516 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
517 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
518 | } | |
519 | ||
520 | /* | |
521 | * Add the new probe to old_p->list. Fail if this is the | |
522 | * second jprobe at the address - two jprobes can't coexist | |
523 | */ | |
524 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) | |
525 | { | |
526 | if (p->break_handler) { | |
527 | if (old_p->break_handler) | |
528 | return -EEXIST; | |
529 | list_add_tail_rcu(&p->list, &old_p->list); | |
530 | old_p->break_handler = aggr_break_handler; | |
531 | } else | |
532 | list_add_rcu(&p->list, &old_p->list); | |
533 | if (p->post_handler && !old_p->post_handler) | |
534 | old_p->post_handler = aggr_post_handler; | |
535 | return 0; | |
536 | } | |
537 | ||
538 | /* | |
539 | * Fill in the required fields of the "manager kprobe". Replace the | |
540 | * earlier kprobe in the hlist with the manager kprobe | |
541 | */ | |
542 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
543 | { | |
544 | copy_kprobe(p, ap); | |
545 | flush_insn_slot(ap); | |
546 | ap->addr = p->addr; | |
547 | ap->pre_handler = aggr_pre_handler; | |
548 | ap->fault_handler = aggr_fault_handler; | |
549 | /* We don't care the kprobe which has gone. */ | |
550 | if (p->post_handler && !kprobe_gone(p)) | |
551 | ap->post_handler = aggr_post_handler; | |
552 | if (p->break_handler && !kprobe_gone(p)) | |
553 | ap->break_handler = aggr_break_handler; | |
554 | ||
555 | INIT_LIST_HEAD(&ap->list); | |
556 | list_add_rcu(&p->list, &ap->list); | |
557 | ||
558 | hlist_replace_rcu(&p->hlist, &ap->hlist); | |
559 | } | |
560 | ||
561 | /* | |
562 | * This is the second or subsequent kprobe at the address - handle | |
563 | * the intricacies | |
564 | */ | |
565 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, | |
566 | struct kprobe *p) | |
567 | { | |
568 | int ret = 0; | |
569 | struct kprobe *ap; | |
570 | ||
571 | if (kprobe_gone(old_p)) { | |
572 | /* | |
573 | * Attempting to insert new probe at the same location that | |
574 | * had a probe in the module vaddr area which already | |
575 | * freed. So, the instruction slot has already been | |
576 | * released. We need a new slot for the new probe. | |
577 | */ | |
578 | ret = arch_prepare_kprobe(old_p); | |
579 | if (ret) | |
580 | return ret; | |
581 | } | |
582 | if (old_p->pre_handler == aggr_pre_handler) { | |
583 | copy_kprobe(old_p, p); | |
584 | ret = add_new_kprobe(old_p, p); | |
585 | ap = old_p; | |
586 | } else { | |
587 | ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
588 | if (!ap) { | |
589 | if (kprobe_gone(old_p)) | |
590 | arch_remove_kprobe(old_p); | |
591 | return -ENOMEM; | |
592 | } | |
593 | add_aggr_kprobe(ap, old_p); | |
594 | copy_kprobe(ap, p); | |
595 | ret = add_new_kprobe(ap, p); | |
596 | } | |
597 | if (kprobe_gone(old_p)) { | |
598 | /* | |
599 | * If the old_p has gone, its breakpoint has been disarmed. | |
600 | * We have to arm it again after preparing real kprobes. | |
601 | */ | |
602 | ap->flags &= ~KPROBE_FLAG_GONE; | |
603 | if (kprobe_enabled) | |
604 | arch_arm_kprobe(ap); | |
605 | } | |
606 | return ret; | |
607 | } | |
608 | ||
609 | static int __kprobes in_kprobes_functions(unsigned long addr) | |
610 | { | |
611 | struct kprobe_blackpoint *kb; | |
612 | ||
613 | if (addr >= (unsigned long)__kprobes_text_start && | |
614 | addr < (unsigned long)__kprobes_text_end) | |
615 | return -EINVAL; | |
616 | /* | |
617 | * If there exists a kprobe_blacklist, verify and | |
618 | * fail any probe registration in the prohibited area | |
619 | */ | |
620 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
621 | if (kb->start_addr) { | |
622 | if (addr >= kb->start_addr && | |
623 | addr < (kb->start_addr + kb->range)) | |
624 | return -EINVAL; | |
625 | } | |
626 | } | |
627 | return 0; | |
628 | } | |
629 | ||
630 | /* | |
631 | * If we have a symbol_name argument, look it up and add the offset field | |
632 | * to it. This way, we can specify a relative address to a symbol. | |
633 | */ | |
634 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
635 | { | |
636 | kprobe_opcode_t *addr = p->addr; | |
637 | if (p->symbol_name) { | |
638 | if (addr) | |
639 | return NULL; | |
640 | kprobe_lookup_name(p->symbol_name, addr); | |
641 | } | |
642 | ||
643 | if (!addr) | |
644 | return NULL; | |
645 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
646 | } | |
647 | ||
648 | int __kprobes register_kprobe(struct kprobe *p) | |
649 | { | |
650 | int ret = 0; | |
651 | struct kprobe *old_p; | |
652 | struct module *probed_mod; | |
653 | kprobe_opcode_t *addr; | |
654 | ||
655 | addr = kprobe_addr(p); | |
656 | if (!addr) | |
657 | return -EINVAL; | |
658 | p->addr = addr; | |
659 | ||
660 | preempt_disable(); | |
661 | if (!__kernel_text_address((unsigned long) p->addr) || | |
662 | in_kprobes_functions((unsigned long) p->addr)) { | |
663 | preempt_enable(); | |
664 | return -EINVAL; | |
665 | } | |
666 | ||
667 | p->flags = 0; | |
668 | /* | |
669 | * Check if are we probing a module. | |
670 | */ | |
671 | probed_mod = __module_text_address((unsigned long) p->addr); | |
672 | if (probed_mod) { | |
673 | /* | |
674 | * We must hold a refcount of the probed module while updating | |
675 | * its code to prohibit unexpected unloading. | |
676 | */ | |
677 | if (unlikely(!try_module_get(probed_mod))) { | |
678 | preempt_enable(); | |
679 | return -EINVAL; | |
680 | } | |
681 | /* | |
682 | * If the module freed .init.text, we couldn't insert | |
683 | * kprobes in there. | |
684 | */ | |
685 | if (within_module_init((unsigned long)p->addr, probed_mod) && | |
686 | probed_mod->state != MODULE_STATE_COMING) { | |
687 | module_put(probed_mod); | |
688 | preempt_enable(); | |
689 | return -EINVAL; | |
690 | } | |
691 | } | |
692 | preempt_enable(); | |
693 | ||
694 | p->nmissed = 0; | |
695 | INIT_LIST_HEAD(&p->list); | |
696 | mutex_lock(&kprobe_mutex); | |
697 | old_p = get_kprobe(p->addr); | |
698 | if (old_p) { | |
699 | ret = register_aggr_kprobe(old_p, p); | |
700 | goto out; | |
701 | } | |
702 | ||
703 | mutex_lock(&text_mutex); | |
704 | ret = arch_prepare_kprobe(p); | |
705 | if (ret) | |
706 | goto out_unlock_text; | |
707 | ||
708 | INIT_HLIST_NODE(&p->hlist); | |
709 | hlist_add_head_rcu(&p->hlist, | |
710 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); | |
711 | ||
712 | if (kprobe_enabled) | |
713 | arch_arm_kprobe(p); | |
714 | ||
715 | out_unlock_text: | |
716 | mutex_unlock(&text_mutex); | |
717 | out: | |
718 | mutex_unlock(&kprobe_mutex); | |
719 | ||
720 | if (probed_mod) | |
721 | module_put(probed_mod); | |
722 | ||
723 | return ret; | |
724 | } | |
725 | ||
726 | /* | |
727 | * Unregister a kprobe without a scheduler synchronization. | |
728 | */ | |
729 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
730 | { | |
731 | struct kprobe *old_p, *list_p; | |
732 | ||
733 | old_p = get_kprobe(p->addr); | |
734 | if (unlikely(!old_p)) | |
735 | return -EINVAL; | |
736 | ||
737 | if (p != old_p) { | |
738 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
739 | if (list_p == p) | |
740 | /* kprobe p is a valid probe */ | |
741 | goto valid_p; | |
742 | return -EINVAL; | |
743 | } | |
744 | valid_p: | |
745 | if (old_p == p || | |
746 | (old_p->pre_handler == aggr_pre_handler && | |
747 | list_is_singular(&old_p->list))) { | |
748 | /* | |
749 | * Only probe on the hash list. Disarm only if kprobes are | |
750 | * enabled and not gone - otherwise, the breakpoint would | |
751 | * already have been removed. We save on flushing icache. | |
752 | */ | |
753 | if (kprobe_enabled && !kprobe_gone(old_p)) { | |
754 | mutex_lock(&text_mutex); | |
755 | arch_disarm_kprobe(p); | |
756 | mutex_unlock(&text_mutex); | |
757 | } | |
758 | hlist_del_rcu(&old_p->hlist); | |
759 | } else { | |
760 | if (p->break_handler && !kprobe_gone(p)) | |
761 | old_p->break_handler = NULL; | |
762 | if (p->post_handler && !kprobe_gone(p)) { | |
763 | list_for_each_entry_rcu(list_p, &old_p->list, list) { | |
764 | if ((list_p != p) && (list_p->post_handler)) | |
765 | goto noclean; | |
766 | } | |
767 | old_p->post_handler = NULL; | |
768 | } | |
769 | noclean: | |
770 | list_del_rcu(&p->list); | |
771 | } | |
772 | return 0; | |
773 | } | |
774 | ||
775 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) | |
776 | { | |
777 | struct kprobe *old_p; | |
778 | ||
779 | if (list_empty(&p->list)) | |
780 | arch_remove_kprobe(p); | |
781 | else if (list_is_singular(&p->list)) { | |
782 | /* "p" is the last child of an aggr_kprobe */ | |
783 | old_p = list_entry(p->list.next, struct kprobe, list); | |
784 | list_del(&p->list); | |
785 | arch_remove_kprobe(old_p); | |
786 | kfree(old_p); | |
787 | } | |
788 | } | |
789 | ||
790 | int __kprobes register_kprobes(struct kprobe **kps, int num) | |
791 | { | |
792 | int i, ret = 0; | |
793 | ||
794 | if (num <= 0) | |
795 | return -EINVAL; | |
796 | for (i = 0; i < num; i++) { | |
797 | ret = register_kprobe(kps[i]); | |
798 | if (ret < 0) { | |
799 | if (i > 0) | |
800 | unregister_kprobes(kps, i); | |
801 | break; | |
802 | } | |
803 | } | |
804 | return ret; | |
805 | } | |
806 | ||
807 | void __kprobes unregister_kprobe(struct kprobe *p) | |
808 | { | |
809 | unregister_kprobes(&p, 1); | |
810 | } | |
811 | ||
812 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) | |
813 | { | |
814 | int i; | |
815 | ||
816 | if (num <= 0) | |
817 | return; | |
818 | mutex_lock(&kprobe_mutex); | |
819 | for (i = 0; i < num; i++) | |
820 | if (__unregister_kprobe_top(kps[i]) < 0) | |
821 | kps[i]->addr = NULL; | |
822 | mutex_unlock(&kprobe_mutex); | |
823 | ||
824 | synchronize_sched(); | |
825 | for (i = 0; i < num; i++) | |
826 | if (kps[i]->addr) | |
827 | __unregister_kprobe_bottom(kps[i]); | |
828 | } | |
829 | ||
830 | static struct notifier_block kprobe_exceptions_nb = { | |
831 | .notifier_call = kprobe_exceptions_notify, | |
832 | .priority = 0x7fffffff /* we need to be notified first */ | |
833 | }; | |
834 | ||
835 | unsigned long __weak arch_deref_entry_point(void *entry) | |
836 | { | |
837 | return (unsigned long)entry; | |
838 | } | |
839 | ||
840 | int __kprobes register_jprobes(struct jprobe **jps, int num) | |
841 | { | |
842 | struct jprobe *jp; | |
843 | int ret = 0, i; | |
844 | ||
845 | if (num <= 0) | |
846 | return -EINVAL; | |
847 | for (i = 0; i < num; i++) { | |
848 | unsigned long addr; | |
849 | jp = jps[i]; | |
850 | addr = arch_deref_entry_point(jp->entry); | |
851 | ||
852 | if (!kernel_text_address(addr)) | |
853 | ret = -EINVAL; | |
854 | else { | |
855 | /* Todo: Verify probepoint is a function entry point */ | |
856 | jp->kp.pre_handler = setjmp_pre_handler; | |
857 | jp->kp.break_handler = longjmp_break_handler; | |
858 | ret = register_kprobe(&jp->kp); | |
859 | } | |
860 | if (ret < 0) { | |
861 | if (i > 0) | |
862 | unregister_jprobes(jps, i); | |
863 | break; | |
864 | } | |
865 | } | |
866 | return ret; | |
867 | } | |
868 | ||
869 | int __kprobes register_jprobe(struct jprobe *jp) | |
870 | { | |
871 | return register_jprobes(&jp, 1); | |
872 | } | |
873 | ||
874 | void __kprobes unregister_jprobe(struct jprobe *jp) | |
875 | { | |
876 | unregister_jprobes(&jp, 1); | |
877 | } | |
878 | ||
879 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) | |
880 | { | |
881 | int i; | |
882 | ||
883 | if (num <= 0) | |
884 | return; | |
885 | mutex_lock(&kprobe_mutex); | |
886 | for (i = 0; i < num; i++) | |
887 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
888 | jps[i]->kp.addr = NULL; | |
889 | mutex_unlock(&kprobe_mutex); | |
890 | ||
891 | synchronize_sched(); | |
892 | for (i = 0; i < num; i++) { | |
893 | if (jps[i]->kp.addr) | |
894 | __unregister_kprobe_bottom(&jps[i]->kp); | |
895 | } | |
896 | } | |
897 | ||
898 | #ifdef CONFIG_KRETPROBES | |
899 | /* | |
900 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
901 | * hits it will set up the return probe. | |
902 | */ | |
903 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
904 | struct pt_regs *regs) | |
905 | { | |
906 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
907 | unsigned long hash, flags = 0; | |
908 | struct kretprobe_instance *ri; | |
909 | ||
910 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
911 | hash = hash_ptr(current, KPROBE_HASH_BITS); | |
912 | spin_lock_irqsave(&rp->lock, flags); | |
913 | if (!hlist_empty(&rp->free_instances)) { | |
914 | ri = hlist_entry(rp->free_instances.first, | |
915 | struct kretprobe_instance, hlist); | |
916 | hlist_del(&ri->hlist); | |
917 | spin_unlock_irqrestore(&rp->lock, flags); | |
918 | ||
919 | ri->rp = rp; | |
920 | ri->task = current; | |
921 | ||
922 | if (rp->entry_handler && rp->entry_handler(ri, regs)) | |
923 | return 0; | |
924 | ||
925 | arch_prepare_kretprobe(ri, regs); | |
926 | ||
927 | /* XXX(hch): why is there no hlist_move_head? */ | |
928 | INIT_HLIST_NODE(&ri->hlist); | |
929 | kretprobe_table_lock(hash, &flags); | |
930 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
931 | kretprobe_table_unlock(hash, &flags); | |
932 | } else { | |
933 | rp->nmissed++; | |
934 | spin_unlock_irqrestore(&rp->lock, flags); | |
935 | } | |
936 | return 0; | |
937 | } | |
938 | ||
939 | int __kprobes register_kretprobe(struct kretprobe *rp) | |
940 | { | |
941 | int ret = 0; | |
942 | struct kretprobe_instance *inst; | |
943 | int i; | |
944 | void *addr; | |
945 | ||
946 | if (kretprobe_blacklist_size) { | |
947 | addr = kprobe_addr(&rp->kp); | |
948 | if (!addr) | |
949 | return -EINVAL; | |
950 | ||
951 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
952 | if (kretprobe_blacklist[i].addr == addr) | |
953 | return -EINVAL; | |
954 | } | |
955 | } | |
956 | ||
957 | rp->kp.pre_handler = pre_handler_kretprobe; | |
958 | rp->kp.post_handler = NULL; | |
959 | rp->kp.fault_handler = NULL; | |
960 | rp->kp.break_handler = NULL; | |
961 | ||
962 | /* Pre-allocate memory for max kretprobe instances */ | |
963 | if (rp->maxactive <= 0) { | |
964 | #ifdef CONFIG_PREEMPT | |
965 | rp->maxactive = max(10, 2 * NR_CPUS); | |
966 | #else | |
967 | rp->maxactive = NR_CPUS; | |
968 | #endif | |
969 | } | |
970 | spin_lock_init(&rp->lock); | |
971 | INIT_HLIST_HEAD(&rp->free_instances); | |
972 | for (i = 0; i < rp->maxactive; i++) { | |
973 | inst = kmalloc(sizeof(struct kretprobe_instance) + | |
974 | rp->data_size, GFP_KERNEL); | |
975 | if (inst == NULL) { | |
976 | free_rp_inst(rp); | |
977 | return -ENOMEM; | |
978 | } | |
979 | INIT_HLIST_NODE(&inst->hlist); | |
980 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
981 | } | |
982 | ||
983 | rp->nmissed = 0; | |
984 | /* Establish function entry probe point */ | |
985 | ret = register_kprobe(&rp->kp); | |
986 | if (ret != 0) | |
987 | free_rp_inst(rp); | |
988 | return ret; | |
989 | } | |
990 | ||
991 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) | |
992 | { | |
993 | int ret = 0, i; | |
994 | ||
995 | if (num <= 0) | |
996 | return -EINVAL; | |
997 | for (i = 0; i < num; i++) { | |
998 | ret = register_kretprobe(rps[i]); | |
999 | if (ret < 0) { | |
1000 | if (i > 0) | |
1001 | unregister_kretprobes(rps, i); | |
1002 | break; | |
1003 | } | |
1004 | } | |
1005 | return ret; | |
1006 | } | |
1007 | ||
1008 | void __kprobes unregister_kretprobe(struct kretprobe *rp) | |
1009 | { | |
1010 | unregister_kretprobes(&rp, 1); | |
1011 | } | |
1012 | ||
1013 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) | |
1014 | { | |
1015 | int i; | |
1016 | ||
1017 | if (num <= 0) | |
1018 | return; | |
1019 | mutex_lock(&kprobe_mutex); | |
1020 | for (i = 0; i < num; i++) | |
1021 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1022 | rps[i]->kp.addr = NULL; | |
1023 | mutex_unlock(&kprobe_mutex); | |
1024 | ||
1025 | synchronize_sched(); | |
1026 | for (i = 0; i < num; i++) { | |
1027 | if (rps[i]->kp.addr) { | |
1028 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1029 | cleanup_rp_inst(rps[i]); | |
1030 | } | |
1031 | } | |
1032 | } | |
1033 | ||
1034 | #else /* CONFIG_KRETPROBES */ | |
1035 | int __kprobes register_kretprobe(struct kretprobe *rp) | |
1036 | { | |
1037 | return -ENOSYS; | |
1038 | } | |
1039 | ||
1040 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) | |
1041 | { | |
1042 | return -ENOSYS; | |
1043 | } | |
1044 | void __kprobes unregister_kretprobe(struct kretprobe *rp) | |
1045 | { | |
1046 | } | |
1047 | ||
1048 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) | |
1049 | { | |
1050 | } | |
1051 | ||
1052 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
1053 | struct pt_regs *regs) | |
1054 | { | |
1055 | return 0; | |
1056 | } | |
1057 | ||
1058 | #endif /* CONFIG_KRETPROBES */ | |
1059 | ||
1060 | /* Set the kprobe gone and remove its instruction buffer. */ | |
1061 | static void __kprobes kill_kprobe(struct kprobe *p) | |
1062 | { | |
1063 | struct kprobe *kp; | |
1064 | p->flags |= KPROBE_FLAG_GONE; | |
1065 | if (p->pre_handler == aggr_pre_handler) { | |
1066 | /* | |
1067 | * If this is an aggr_kprobe, we have to list all the | |
1068 | * chained probes and mark them GONE. | |
1069 | */ | |
1070 | list_for_each_entry_rcu(kp, &p->list, list) | |
1071 | kp->flags |= KPROBE_FLAG_GONE; | |
1072 | p->post_handler = NULL; | |
1073 | p->break_handler = NULL; | |
1074 | } | |
1075 | /* | |
1076 | * Here, we can remove insn_slot safely, because no thread calls | |
1077 | * the original probed function (which will be freed soon) any more. | |
1078 | */ | |
1079 | arch_remove_kprobe(p); | |
1080 | } | |
1081 | ||
1082 | /* Module notifier call back, checking kprobes on the module */ | |
1083 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, | |
1084 | unsigned long val, void *data) | |
1085 | { | |
1086 | struct module *mod = data; | |
1087 | struct hlist_head *head; | |
1088 | struct hlist_node *node; | |
1089 | struct kprobe *p; | |
1090 | unsigned int i; | |
1091 | int checkcore = (val == MODULE_STATE_GOING); | |
1092 | ||
1093 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) | |
1094 | return NOTIFY_DONE; | |
1095 | ||
1096 | /* | |
1097 | * When MODULE_STATE_GOING was notified, both of module .text and | |
1098 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
1099 | * notified, only .init.text section would be freed. We need to | |
1100 | * disable kprobes which have been inserted in the sections. | |
1101 | */ | |
1102 | mutex_lock(&kprobe_mutex); | |
1103 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1104 | head = &kprobe_table[i]; | |
1105 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
1106 | if (within_module_init((unsigned long)p->addr, mod) || | |
1107 | (checkcore && | |
1108 | within_module_core((unsigned long)p->addr, mod))) { | |
1109 | /* | |
1110 | * The vaddr this probe is installed will soon | |
1111 | * be vfreed buy not synced to disk. Hence, | |
1112 | * disarming the breakpoint isn't needed. | |
1113 | */ | |
1114 | kill_kprobe(p); | |
1115 | } | |
1116 | } | |
1117 | mutex_unlock(&kprobe_mutex); | |
1118 | return NOTIFY_DONE; | |
1119 | } | |
1120 | ||
1121 | static struct notifier_block kprobe_module_nb = { | |
1122 | .notifier_call = kprobes_module_callback, | |
1123 | .priority = 0 | |
1124 | }; | |
1125 | ||
1126 | static int __init init_kprobes(void) | |
1127 | { | |
1128 | int i, err = 0; | |
1129 | unsigned long offset = 0, size = 0; | |
1130 | char *modname, namebuf[128]; | |
1131 | const char *symbol_name; | |
1132 | void *addr; | |
1133 | struct kprobe_blackpoint *kb; | |
1134 | ||
1135 | /* FIXME allocate the probe table, currently defined statically */ | |
1136 | /* initialize all list heads */ | |
1137 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1138 | INIT_HLIST_HEAD(&kprobe_table[i]); | |
1139 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); | |
1140 | spin_lock_init(&(kretprobe_table_locks[i].lock)); | |
1141 | } | |
1142 | ||
1143 | /* | |
1144 | * Lookup and populate the kprobe_blacklist. | |
1145 | * | |
1146 | * Unlike the kretprobe blacklist, we'll need to determine | |
1147 | * the range of addresses that belong to the said functions, | |
1148 | * since a kprobe need not necessarily be at the beginning | |
1149 | * of a function. | |
1150 | */ | |
1151 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1152 | kprobe_lookup_name(kb->name, addr); | |
1153 | if (!addr) | |
1154 | continue; | |
1155 | ||
1156 | kb->start_addr = (unsigned long)addr; | |
1157 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1158 | &size, &offset, &modname, namebuf); | |
1159 | if (!symbol_name) | |
1160 | kb->range = 0; | |
1161 | else | |
1162 | kb->range = size; | |
1163 | } | |
1164 | ||
1165 | if (kretprobe_blacklist_size) { | |
1166 | /* lookup the function address from its name */ | |
1167 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1168 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1169 | kretprobe_blacklist[i].addr); | |
1170 | if (!kretprobe_blacklist[i].addr) | |
1171 | printk("kretprobe: lookup failed: %s\n", | |
1172 | kretprobe_blacklist[i].name); | |
1173 | } | |
1174 | } | |
1175 | ||
1176 | /* By default, kprobes are enabled */ | |
1177 | kprobe_enabled = true; | |
1178 | ||
1179 | err = arch_init_kprobes(); | |
1180 | if (!err) | |
1181 | err = register_die_notifier(&kprobe_exceptions_nb); | |
1182 | if (!err) | |
1183 | err = register_module_notifier(&kprobe_module_nb); | |
1184 | ||
1185 | kprobes_initialized = (err == 0); | |
1186 | ||
1187 | if (!err) | |
1188 | init_test_probes(); | |
1189 | return err; | |
1190 | } | |
1191 | ||
1192 | #ifdef CONFIG_DEBUG_FS | |
1193 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
1194 | const char *sym, int offset,char *modname) | |
1195 | { | |
1196 | char *kprobe_type; | |
1197 | ||
1198 | if (p->pre_handler == pre_handler_kretprobe) | |
1199 | kprobe_type = "r"; | |
1200 | else if (p->pre_handler == setjmp_pre_handler) | |
1201 | kprobe_type = "j"; | |
1202 | else | |
1203 | kprobe_type = "k"; | |
1204 | if (sym) | |
1205 | seq_printf(pi, "%p %s %s+0x%x %s %s\n", p->addr, kprobe_type, | |
1206 | sym, offset, (modname ? modname : " "), | |
1207 | (kprobe_gone(p) ? "[GONE]" : "")); | |
1208 | else | |
1209 | seq_printf(pi, "%p %s %p %s\n", p->addr, kprobe_type, p->addr, | |
1210 | (kprobe_gone(p) ? "[GONE]" : "")); | |
1211 | } | |
1212 | ||
1213 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1214 | { | |
1215 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1216 | } | |
1217 | ||
1218 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1219 | { | |
1220 | (*pos)++; | |
1221 | if (*pos >= KPROBE_TABLE_SIZE) | |
1222 | return NULL; | |
1223 | return pos; | |
1224 | } | |
1225 | ||
1226 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1227 | { | |
1228 | /* Nothing to do */ | |
1229 | } | |
1230 | ||
1231 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1232 | { | |
1233 | struct hlist_head *head; | |
1234 | struct hlist_node *node; | |
1235 | struct kprobe *p, *kp; | |
1236 | const char *sym = NULL; | |
1237 | unsigned int i = *(loff_t *) v; | |
1238 | unsigned long offset = 0; | |
1239 | char *modname, namebuf[128]; | |
1240 | ||
1241 | head = &kprobe_table[i]; | |
1242 | preempt_disable(); | |
1243 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
1244 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, | |
1245 | &offset, &modname, namebuf); | |
1246 | if (p->pre_handler == aggr_pre_handler) { | |
1247 | list_for_each_entry_rcu(kp, &p->list, list) | |
1248 | report_probe(pi, kp, sym, offset, modname); | |
1249 | } else | |
1250 | report_probe(pi, p, sym, offset, modname); | |
1251 | } | |
1252 | preempt_enable(); | |
1253 | return 0; | |
1254 | } | |
1255 | ||
1256 | static struct seq_operations kprobes_seq_ops = { | |
1257 | .start = kprobe_seq_start, | |
1258 | .next = kprobe_seq_next, | |
1259 | .stop = kprobe_seq_stop, | |
1260 | .show = show_kprobe_addr | |
1261 | }; | |
1262 | ||
1263 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1264 | { | |
1265 | return seq_open(filp, &kprobes_seq_ops); | |
1266 | } | |
1267 | ||
1268 | static struct file_operations debugfs_kprobes_operations = { | |
1269 | .open = kprobes_open, | |
1270 | .read = seq_read, | |
1271 | .llseek = seq_lseek, | |
1272 | .release = seq_release, | |
1273 | }; | |
1274 | ||
1275 | static void __kprobes enable_all_kprobes(void) | |
1276 | { | |
1277 | struct hlist_head *head; | |
1278 | struct hlist_node *node; | |
1279 | struct kprobe *p; | |
1280 | unsigned int i; | |
1281 | ||
1282 | mutex_lock(&kprobe_mutex); | |
1283 | ||
1284 | /* If kprobes are already enabled, just return */ | |
1285 | if (kprobe_enabled) | |
1286 | goto already_enabled; | |
1287 | ||
1288 | mutex_lock(&text_mutex); | |
1289 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1290 | head = &kprobe_table[i]; | |
1291 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
1292 | if (!kprobe_gone(p)) | |
1293 | arch_arm_kprobe(p); | |
1294 | } | |
1295 | mutex_unlock(&text_mutex); | |
1296 | ||
1297 | kprobe_enabled = true; | |
1298 | printk(KERN_INFO "Kprobes globally enabled\n"); | |
1299 | ||
1300 | already_enabled: | |
1301 | mutex_unlock(&kprobe_mutex); | |
1302 | return; | |
1303 | } | |
1304 | ||
1305 | static void __kprobes disable_all_kprobes(void) | |
1306 | { | |
1307 | struct hlist_head *head; | |
1308 | struct hlist_node *node; | |
1309 | struct kprobe *p; | |
1310 | unsigned int i; | |
1311 | ||
1312 | mutex_lock(&kprobe_mutex); | |
1313 | ||
1314 | /* If kprobes are already disabled, just return */ | |
1315 | if (!kprobe_enabled) | |
1316 | goto already_disabled; | |
1317 | ||
1318 | kprobe_enabled = false; | |
1319 | printk(KERN_INFO "Kprobes globally disabled\n"); | |
1320 | mutex_lock(&text_mutex); | |
1321 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1322 | head = &kprobe_table[i]; | |
1323 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
1324 | if (!arch_trampoline_kprobe(p) && !kprobe_gone(p)) | |
1325 | arch_disarm_kprobe(p); | |
1326 | } | |
1327 | } | |
1328 | ||
1329 | mutex_unlock(&text_mutex); | |
1330 | mutex_unlock(&kprobe_mutex); | |
1331 | /* Allow all currently running kprobes to complete */ | |
1332 | synchronize_sched(); | |
1333 | return; | |
1334 | ||
1335 | already_disabled: | |
1336 | mutex_unlock(&kprobe_mutex); | |
1337 | return; | |
1338 | } | |
1339 | ||
1340 | /* | |
1341 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1342 | * when the bool state is switched. We can reuse that facility when | |
1343 | * available | |
1344 | */ | |
1345 | static ssize_t read_enabled_file_bool(struct file *file, | |
1346 | char __user *user_buf, size_t count, loff_t *ppos) | |
1347 | { | |
1348 | char buf[3]; | |
1349 | ||
1350 | if (kprobe_enabled) | |
1351 | buf[0] = '1'; | |
1352 | else | |
1353 | buf[0] = '0'; | |
1354 | buf[1] = '\n'; | |
1355 | buf[2] = 0x00; | |
1356 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1357 | } | |
1358 | ||
1359 | static ssize_t write_enabled_file_bool(struct file *file, | |
1360 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1361 | { | |
1362 | char buf[32]; | |
1363 | int buf_size; | |
1364 | ||
1365 | buf_size = min(count, (sizeof(buf)-1)); | |
1366 | if (copy_from_user(buf, user_buf, buf_size)) | |
1367 | return -EFAULT; | |
1368 | ||
1369 | switch (buf[0]) { | |
1370 | case 'y': | |
1371 | case 'Y': | |
1372 | case '1': | |
1373 | enable_all_kprobes(); | |
1374 | break; | |
1375 | case 'n': | |
1376 | case 'N': | |
1377 | case '0': | |
1378 | disable_all_kprobes(); | |
1379 | break; | |
1380 | } | |
1381 | ||
1382 | return count; | |
1383 | } | |
1384 | ||
1385 | static struct file_operations fops_kp = { | |
1386 | .read = read_enabled_file_bool, | |
1387 | .write = write_enabled_file_bool, | |
1388 | }; | |
1389 | ||
1390 | static int __kprobes debugfs_kprobe_init(void) | |
1391 | { | |
1392 | struct dentry *dir, *file; | |
1393 | unsigned int value = 1; | |
1394 | ||
1395 | dir = debugfs_create_dir("kprobes", NULL); | |
1396 | if (!dir) | |
1397 | return -ENOMEM; | |
1398 | ||
1399 | file = debugfs_create_file("list", 0444, dir, NULL, | |
1400 | &debugfs_kprobes_operations); | |
1401 | if (!file) { | |
1402 | debugfs_remove(dir); | |
1403 | return -ENOMEM; | |
1404 | } | |
1405 | ||
1406 | file = debugfs_create_file("enabled", 0600, dir, | |
1407 | &value, &fops_kp); | |
1408 | if (!file) { | |
1409 | debugfs_remove(dir); | |
1410 | return -ENOMEM; | |
1411 | } | |
1412 | ||
1413 | return 0; | |
1414 | } | |
1415 | ||
1416 | late_initcall(debugfs_kprobe_init); | |
1417 | #endif /* CONFIG_DEBUG_FS */ | |
1418 | ||
1419 | module_init(init_kprobes); | |
1420 | ||
1421 | EXPORT_SYMBOL_GPL(register_kprobe); | |
1422 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
1423 | EXPORT_SYMBOL_GPL(register_kprobes); | |
1424 | EXPORT_SYMBOL_GPL(unregister_kprobes); | |
1425 | EXPORT_SYMBOL_GPL(register_jprobe); | |
1426 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
1427 | EXPORT_SYMBOL_GPL(register_jprobes); | |
1428 | EXPORT_SYMBOL_GPL(unregister_jprobes); | |
1429 | EXPORT_SYMBOL_GPL(jprobe_return); | |
1430 | EXPORT_SYMBOL_GPL(register_kretprobe); | |
1431 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
1432 | EXPORT_SYMBOL_GPL(register_kretprobes); | |
1433 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |