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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/sysctl.h> |
46 | #include <linux/kdebug.h> |
47 | #include <linux/memory.h> |
48 | #include <linux/ftrace.h> |
49 | #include <linux/cpu.h> |
50 | |
51 | #include <asm-generic/sections.h> |
52 | #include <asm/cacheflush.h> |
53 | #include <asm/errno.h> |
54 | #include <asm/uaccess.h> |
55 | |
56 | #define KPROBE_HASH_BITS 6 |
57 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
58 | |
59 | |
60 | /* |
61 | * Some oddball architectures like 64bit powerpc have function descriptors |
62 | * so this must be overridable. |
63 | */ |
64 | #ifndef kprobe_lookup_name |
65 | #define kprobe_lookup_name(name, addr) \ |
66 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) |
67 | #endif |
68 | |
69 | static int kprobes_initialized; |
70 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
71 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
72 | |
73 | /* NOTE: change this value only with kprobe_mutex held */ |
74 | static bool kprobes_all_disarmed; |
75 | |
76 | static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
77 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
78 | static struct { |
79 | spinlock_t lock ____cacheline_aligned_in_smp; |
80 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
81 | |
82 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
83 | { |
84 | return &(kretprobe_table_locks[hash].lock); |
85 | } |
86 | |
87 | /* |
88 | * Normally, functions that we'd want to prohibit kprobes in, are marked |
89 | * __kprobes. But, there are cases where such functions already belong to |
90 | * a different section (__sched for preempt_schedule) |
91 | * |
92 | * For such cases, we now have a blacklist |
93 | */ |
94 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
95 | {"preempt_schedule",}, |
96 | {"native_get_debugreg",}, |
97 | {"irq_entries_start",}, |
98 | {"common_interrupt",}, |
99 | {"mcount",}, /* mcount can be called from everywhere */ |
100 | {NULL} /* Terminator */ |
101 | }; |
102 | |
103 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
104 | /* |
105 | * kprobe->ainsn.insn points to the copy of the instruction to be |
106 | * single-stepped. x86_64, POWER4 and above have no-exec support and |
107 | * stepping on the instruction on a vmalloced/kmalloced/data page |
108 | * is a recipe for disaster |
109 | */ |
110 | struct kprobe_insn_page { |
111 | struct list_head list; |
112 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
113 | int nused; |
114 | int ngarbage; |
115 | char slot_used[]; |
116 | }; |
117 | |
118 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
119 | (offsetof(struct kprobe_insn_page, slot_used) + \ |
120 | (sizeof(char) * (slots))) |
121 | |
122 | struct kprobe_insn_cache { |
123 | struct list_head pages; /* list of kprobe_insn_page */ |
124 | size_t insn_size; /* size of instruction slot */ |
125 | int nr_garbage; |
126 | }; |
127 | |
128 | static int slots_per_page(struct kprobe_insn_cache *c) |
129 | { |
130 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); |
131 | } |
132 | |
133 | enum kprobe_slot_state { |
134 | SLOT_CLEAN = 0, |
135 | SLOT_DIRTY = 1, |
136 | SLOT_USED = 2, |
137 | }; |
138 | |
139 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ |
140 | static struct kprobe_insn_cache kprobe_insn_slots = { |
141 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
142 | .insn_size = MAX_INSN_SIZE, |
143 | .nr_garbage = 0, |
144 | }; |
145 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); |
146 | |
147 | /** |
148 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
149 | * We allocate an executable page if there's no room on existing ones. |
150 | */ |
151 | static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
152 | { |
153 | struct kprobe_insn_page *kip; |
154 | |
155 | retry: |
156 | list_for_each_entry(kip, &c->pages, list) { |
157 | if (kip->nused < slots_per_page(c)) { |
158 | int i; |
159 | for (i = 0; i < slots_per_page(c); i++) { |
160 | if (kip->slot_used[i] == SLOT_CLEAN) { |
161 | kip->slot_used[i] = SLOT_USED; |
162 | kip->nused++; |
163 | return kip->insns + (i * c->insn_size); |
164 | } |
165 | } |
166 | /* kip->nused is broken. Fix it. */ |
167 | kip->nused = slots_per_page(c); |
168 | WARN_ON(1); |
169 | } |
170 | } |
171 | |
172 | /* If there are any garbage slots, collect it and try again. */ |
173 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
174 | goto retry; |
175 | |
176 | /* All out of space. Need to allocate a new page. */ |
177 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); |
178 | if (!kip) |
179 | return NULL; |
180 | |
181 | /* |
182 | * Use module_alloc so this page is within +/- 2GB of where the |
183 | * kernel image and loaded module images reside. This is required |
184 | * so x86_64 can correctly handle the %rip-relative fixups. |
185 | */ |
186 | kip->insns = module_alloc(PAGE_SIZE); |
187 | if (!kip->insns) { |
188 | kfree(kip); |
189 | return NULL; |
190 | } |
191 | INIT_LIST_HEAD(&kip->list); |
192 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
193 | kip->slot_used[0] = SLOT_USED; |
194 | kip->nused = 1; |
195 | kip->ngarbage = 0; |
196 | list_add(&kip->list, &c->pages); |
197 | return kip->insns; |
198 | } |
199 | |
200 | |
201 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
202 | { |
203 | kprobe_opcode_t *ret = NULL; |
204 | |
205 | mutex_lock(&kprobe_insn_mutex); |
206 | ret = __get_insn_slot(&kprobe_insn_slots); |
207 | mutex_unlock(&kprobe_insn_mutex); |
208 | |
209 | return ret; |
210 | } |
211 | |
212 | /* Return 1 if all garbages are collected, otherwise 0. */ |
213 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) |
214 | { |
215 | kip->slot_used[idx] = SLOT_CLEAN; |
216 | kip->nused--; |
217 | if (kip->nused == 0) { |
218 | /* |
219 | * Page is no longer in use. Free it unless |
220 | * it's the last one. We keep the last one |
221 | * so as not to have to set it up again the |
222 | * next time somebody inserts a probe. |
223 | */ |
224 | if (!list_is_singular(&kip->list)) { |
225 | list_del(&kip->list); |
226 | module_free(NULL, kip->insns); |
227 | kfree(kip); |
228 | } |
229 | return 1; |
230 | } |
231 | return 0; |
232 | } |
233 | |
234 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
235 | { |
236 | struct kprobe_insn_page *kip, *next; |
237 | |
238 | /* Ensure no-one is interrupted on the garbages */ |
239 | synchronize_sched(); |
240 | |
241 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
242 | int i; |
243 | if (kip->ngarbage == 0) |
244 | continue; |
245 | kip->ngarbage = 0; /* we will collect all garbages */ |
246 | for (i = 0; i < slots_per_page(c); i++) { |
247 | if (kip->slot_used[i] == SLOT_DIRTY && |
248 | collect_one_slot(kip, i)) |
249 | break; |
250 | } |
251 | } |
252 | c->nr_garbage = 0; |
253 | return 0; |
254 | } |
255 | |
256 | static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
257 | kprobe_opcode_t *slot, int dirty) |
258 | { |
259 | struct kprobe_insn_page *kip; |
260 | |
261 | list_for_each_entry(kip, &c->pages, list) { |
262 | long idx = ((long)slot - (long)kip->insns) / |
263 | (c->insn_size * sizeof(kprobe_opcode_t)); |
264 | if (idx >= 0 && idx < slots_per_page(c)) { |
265 | WARN_ON(kip->slot_used[idx] != SLOT_USED); |
266 | if (dirty) { |
267 | kip->slot_used[idx] = SLOT_DIRTY; |
268 | kip->ngarbage++; |
269 | if (++c->nr_garbage > slots_per_page(c)) |
270 | collect_garbage_slots(c); |
271 | } else |
272 | collect_one_slot(kip, idx); |
273 | return; |
274 | } |
275 | } |
276 | /* Could not free this slot. */ |
277 | WARN_ON(1); |
278 | } |
279 | |
280 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
281 | { |
282 | mutex_lock(&kprobe_insn_mutex); |
283 | __free_insn_slot(&kprobe_insn_slots, slot, dirty); |
284 | mutex_unlock(&kprobe_insn_mutex); |
285 | } |
286 | #ifdef CONFIG_OPTPROBES |
287 | /* For optimized_kprobe buffer */ |
288 | static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ |
289 | static struct kprobe_insn_cache kprobe_optinsn_slots = { |
290 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
291 | /* .insn_size is initialized later */ |
292 | .nr_garbage = 0, |
293 | }; |
294 | /* Get a slot for optimized_kprobe buffer */ |
295 | kprobe_opcode_t __kprobes *get_optinsn_slot(void) |
296 | { |
297 | kprobe_opcode_t *ret = NULL; |
298 | |
299 | mutex_lock(&kprobe_optinsn_mutex); |
300 | ret = __get_insn_slot(&kprobe_optinsn_slots); |
301 | mutex_unlock(&kprobe_optinsn_mutex); |
302 | |
303 | return ret; |
304 | } |
305 | |
306 | void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) |
307 | { |
308 | mutex_lock(&kprobe_optinsn_mutex); |
309 | __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); |
310 | mutex_unlock(&kprobe_optinsn_mutex); |
311 | } |
312 | #endif |
313 | #endif |
314 | |
315 | /* We have preemption disabled.. so it is safe to use __ versions */ |
316 | static inline void set_kprobe_instance(struct kprobe *kp) |
317 | { |
318 | __get_cpu_var(kprobe_instance) = kp; |
319 | } |
320 | |
321 | static inline void reset_kprobe_instance(void) |
322 | { |
323 | __get_cpu_var(kprobe_instance) = NULL; |
324 | } |
325 | |
326 | /* |
327 | * This routine is called either: |
328 | * - under the kprobe_mutex - during kprobe_[un]register() |
329 | * OR |
330 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
331 | */ |
332 | struct kprobe __kprobes *get_kprobe(void *addr) |
333 | { |
334 | struct hlist_head *head; |
335 | struct hlist_node *node; |
336 | struct kprobe *p; |
337 | |
338 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
339 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
340 | if (p->addr == addr) |
341 | return p; |
342 | } |
343 | |
344 | return NULL; |
345 | } |
346 | |
347 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
348 | |
349 | /* Return true if the kprobe is an aggregator */ |
350 | static inline int kprobe_aggrprobe(struct kprobe *p) |
351 | { |
352 | return p->pre_handler == aggr_pre_handler; |
353 | } |
354 | |
355 | /* |
356 | * Keep all fields in the kprobe consistent |
357 | */ |
358 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) |
359 | { |
360 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); |
361 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); |
362 | } |
363 | |
364 | #ifdef CONFIG_OPTPROBES |
365 | /* NOTE: change this value only with kprobe_mutex held */ |
366 | static bool kprobes_allow_optimization; |
367 | |
368 | /* |
369 | * Call all pre_handler on the list, but ignores its return value. |
370 | * This must be called from arch-dep optimized caller. |
371 | */ |
372 | void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
373 | { |
374 | struct kprobe *kp; |
375 | |
376 | list_for_each_entry_rcu(kp, &p->list, list) { |
377 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
378 | set_kprobe_instance(kp); |
379 | kp->pre_handler(kp, regs); |
380 | } |
381 | reset_kprobe_instance(); |
382 | } |
383 | } |
384 | |
385 | /* Return true(!0) if the kprobe is ready for optimization. */ |
386 | static inline int kprobe_optready(struct kprobe *p) |
387 | { |
388 | struct optimized_kprobe *op; |
389 | |
390 | if (kprobe_aggrprobe(p)) { |
391 | op = container_of(p, struct optimized_kprobe, kp); |
392 | return arch_prepared_optinsn(&op->optinsn); |
393 | } |
394 | |
395 | return 0; |
396 | } |
397 | |
398 | /* |
399 | * Return an optimized kprobe whose optimizing code replaces |
400 | * instructions including addr (exclude breakpoint). |
401 | */ |
402 | struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) |
403 | { |
404 | int i; |
405 | struct kprobe *p = NULL; |
406 | struct optimized_kprobe *op; |
407 | |
408 | /* Don't check i == 0, since that is a breakpoint case. */ |
409 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) |
410 | p = get_kprobe((void *)(addr - i)); |
411 | |
412 | if (p && kprobe_optready(p)) { |
413 | op = container_of(p, struct optimized_kprobe, kp); |
414 | if (arch_within_optimized_kprobe(op, addr)) |
415 | return p; |
416 | } |
417 | |
418 | return NULL; |
419 | } |
420 | |
421 | /* Optimization staging list, protected by kprobe_mutex */ |
422 | static LIST_HEAD(optimizing_list); |
423 | |
424 | static void kprobe_optimizer(struct work_struct *work); |
425 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); |
426 | #define OPTIMIZE_DELAY 5 |
427 | |
428 | /* Kprobe jump optimizer */ |
429 | static __kprobes void kprobe_optimizer(struct work_struct *work) |
430 | { |
431 | struct optimized_kprobe *op, *tmp; |
432 | |
433 | /* Lock modules while optimizing kprobes */ |
434 | mutex_lock(&module_mutex); |
435 | mutex_lock(&kprobe_mutex); |
436 | if (kprobes_all_disarmed || !kprobes_allow_optimization) |
437 | goto end; |
438 | |
439 | /* |
440 | * Wait for quiesence period to ensure all running interrupts |
441 | * are done. Because optprobe may modify multiple instructions |
442 | * there is a chance that Nth instruction is interrupted. In that |
443 | * case, running interrupt can return to 2nd-Nth byte of jump |
444 | * instruction. This wait is for avoiding it. |
445 | */ |
446 | synchronize_sched(); |
447 | |
448 | /* |
449 | * The optimization/unoptimization refers online_cpus via |
450 | * stop_machine() and cpu-hotplug modifies online_cpus. |
451 | * And same time, text_mutex will be held in cpu-hotplug and here. |
452 | * This combination can cause a deadlock (cpu-hotplug try to lock |
453 | * text_mutex but stop_machine can not be done because online_cpus |
454 | * has been changed) |
455 | * To avoid this deadlock, we need to call get_online_cpus() |
456 | * for preventing cpu-hotplug outside of text_mutex locking. |
457 | */ |
458 | get_online_cpus(); |
459 | mutex_lock(&text_mutex); |
460 | list_for_each_entry_safe(op, tmp, &optimizing_list, list) { |
461 | WARN_ON(kprobe_disabled(&op->kp)); |
462 | if (arch_optimize_kprobe(op) < 0) |
463 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
464 | list_del_init(&op->list); |
465 | } |
466 | mutex_unlock(&text_mutex); |
467 | put_online_cpus(); |
468 | end: |
469 | mutex_unlock(&kprobe_mutex); |
470 | mutex_unlock(&module_mutex); |
471 | } |
472 | |
473 | /* Optimize kprobe if p is ready to be optimized */ |
474 | static __kprobes void optimize_kprobe(struct kprobe *p) |
475 | { |
476 | struct optimized_kprobe *op; |
477 | |
478 | /* Check if the kprobe is disabled or not ready for optimization. */ |
479 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
480 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
481 | return; |
482 | |
483 | /* Both of break_handler and post_handler are not supported. */ |
484 | if (p->break_handler || p->post_handler) |
485 | return; |
486 | |
487 | op = container_of(p, struct optimized_kprobe, kp); |
488 | |
489 | /* Check there is no other kprobes at the optimized instructions */ |
490 | if (arch_check_optimized_kprobe(op) < 0) |
491 | return; |
492 | |
493 | /* Check if it is already optimized. */ |
494 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) |
495 | return; |
496 | |
497 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
498 | list_add(&op->list, &optimizing_list); |
499 | if (!delayed_work_pending(&optimizing_work)) |
500 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
501 | } |
502 | |
503 | /* Unoptimize a kprobe if p is optimized */ |
504 | static __kprobes void unoptimize_kprobe(struct kprobe *p) |
505 | { |
506 | struct optimized_kprobe *op; |
507 | |
508 | if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) { |
509 | op = container_of(p, struct optimized_kprobe, kp); |
510 | if (!list_empty(&op->list)) |
511 | /* Dequeue from the optimization queue */ |
512 | list_del_init(&op->list); |
513 | else |
514 | /* Replace jump with break */ |
515 | arch_unoptimize_kprobe(op); |
516 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
517 | } |
518 | } |
519 | |
520 | /* Remove optimized instructions */ |
521 | static void __kprobes kill_optimized_kprobe(struct kprobe *p) |
522 | { |
523 | struct optimized_kprobe *op; |
524 | |
525 | op = container_of(p, struct optimized_kprobe, kp); |
526 | if (!list_empty(&op->list)) { |
527 | /* Dequeue from the optimization queue */ |
528 | list_del_init(&op->list); |
529 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
530 | } |
531 | /* Don't unoptimize, because the target code will be freed. */ |
532 | arch_remove_optimized_kprobe(op); |
533 | } |
534 | |
535 | /* Try to prepare optimized instructions */ |
536 | static __kprobes void prepare_optimized_kprobe(struct kprobe *p) |
537 | { |
538 | struct optimized_kprobe *op; |
539 | |
540 | op = container_of(p, struct optimized_kprobe, kp); |
541 | arch_prepare_optimized_kprobe(op); |
542 | } |
543 | |
544 | /* Free optimized instructions and optimized_kprobe */ |
545 | static __kprobes void free_aggr_kprobe(struct kprobe *p) |
546 | { |
547 | struct optimized_kprobe *op; |
548 | |
549 | op = container_of(p, struct optimized_kprobe, kp); |
550 | arch_remove_optimized_kprobe(op); |
551 | kfree(op); |
552 | } |
553 | |
554 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
555 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
556 | { |
557 | struct optimized_kprobe *op; |
558 | |
559 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); |
560 | if (!op) |
561 | return NULL; |
562 | |
563 | INIT_LIST_HEAD(&op->list); |
564 | op->kp.addr = p->addr; |
565 | arch_prepare_optimized_kprobe(op); |
566 | |
567 | return &op->kp; |
568 | } |
569 | |
570 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
571 | |
572 | /* |
573 | * Prepare an optimized_kprobe and optimize it |
574 | * NOTE: p must be a normal registered kprobe |
575 | */ |
576 | static __kprobes void try_to_optimize_kprobe(struct kprobe *p) |
577 | { |
578 | struct kprobe *ap; |
579 | struct optimized_kprobe *op; |
580 | |
581 | ap = alloc_aggr_kprobe(p); |
582 | if (!ap) |
583 | return; |
584 | |
585 | op = container_of(ap, struct optimized_kprobe, kp); |
586 | if (!arch_prepared_optinsn(&op->optinsn)) { |
587 | /* If failed to setup optimizing, fallback to kprobe */ |
588 | free_aggr_kprobe(ap); |
589 | return; |
590 | } |
591 | |
592 | init_aggr_kprobe(ap, p); |
593 | optimize_kprobe(ap); |
594 | } |
595 | |
596 | #ifdef CONFIG_SYSCTL |
597 | static void __kprobes optimize_all_kprobes(void) |
598 | { |
599 | struct hlist_head *head; |
600 | struct hlist_node *node; |
601 | struct kprobe *p; |
602 | unsigned int i; |
603 | |
604 | /* If optimization is already allowed, just return */ |
605 | if (kprobes_allow_optimization) |
606 | return; |
607 | |
608 | kprobes_allow_optimization = true; |
609 | mutex_lock(&text_mutex); |
610 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
611 | head = &kprobe_table[i]; |
612 | hlist_for_each_entry_rcu(p, node, head, hlist) |
613 | if (!kprobe_disabled(p)) |
614 | optimize_kprobe(p); |
615 | } |
616 | mutex_unlock(&text_mutex); |
617 | printk(KERN_INFO "Kprobes globally optimized\n"); |
618 | } |
619 | |
620 | static void __kprobes unoptimize_all_kprobes(void) |
621 | { |
622 | struct hlist_head *head; |
623 | struct hlist_node *node; |
624 | struct kprobe *p; |
625 | unsigned int i; |
626 | |
627 | /* If optimization is already prohibited, just return */ |
628 | if (!kprobes_allow_optimization) |
629 | return; |
630 | |
631 | kprobes_allow_optimization = false; |
632 | printk(KERN_INFO "Kprobes globally unoptimized\n"); |
633 | get_online_cpus(); /* For avoiding text_mutex deadlock */ |
634 | mutex_lock(&text_mutex); |
635 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
636 | head = &kprobe_table[i]; |
637 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
638 | if (!kprobe_disabled(p)) |
639 | unoptimize_kprobe(p); |
640 | } |
641 | } |
642 | |
643 | mutex_unlock(&text_mutex); |
644 | put_online_cpus(); |
645 | /* Allow all currently running kprobes to complete */ |
646 | synchronize_sched(); |
647 | } |
648 | |
649 | int sysctl_kprobes_optimization; |
650 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, |
651 | void __user *buffer, size_t *length, |
652 | loff_t *ppos) |
653 | { |
654 | int ret; |
655 | |
656 | mutex_lock(&kprobe_mutex); |
657 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
658 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); |
659 | |
660 | if (sysctl_kprobes_optimization) |
661 | optimize_all_kprobes(); |
662 | else |
663 | unoptimize_all_kprobes(); |
664 | mutex_unlock(&kprobe_mutex); |
665 | |
666 | return ret; |
667 | } |
668 | #endif /* CONFIG_SYSCTL */ |
669 | |
670 | static void __kprobes __arm_kprobe(struct kprobe *p) |
671 | { |
672 | struct kprobe *old_p; |
673 | |
674 | /* Check collision with other optimized kprobes */ |
675 | old_p = get_optimized_kprobe((unsigned long)p->addr); |
676 | if (unlikely(old_p)) |
677 | unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */ |
678 | |
679 | arch_arm_kprobe(p); |
680 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ |
681 | } |
682 | |
683 | static void __kprobes __disarm_kprobe(struct kprobe *p) |
684 | { |
685 | struct kprobe *old_p; |
686 | |
687 | unoptimize_kprobe(p); /* Try to unoptimize */ |
688 | arch_disarm_kprobe(p); |
689 | |
690 | /* If another kprobe was blocked, optimize it. */ |
691 | old_p = get_optimized_kprobe((unsigned long)p->addr); |
692 | if (unlikely(old_p)) |
693 | optimize_kprobe(old_p); |
694 | } |
695 | |
696 | #else /* !CONFIG_OPTPROBES */ |
697 | |
698 | #define optimize_kprobe(p) do {} while (0) |
699 | #define unoptimize_kprobe(p) do {} while (0) |
700 | #define kill_optimized_kprobe(p) do {} while (0) |
701 | #define prepare_optimized_kprobe(p) do {} while (0) |
702 | #define try_to_optimize_kprobe(p) do {} while (0) |
703 | #define __arm_kprobe(p) arch_arm_kprobe(p) |
704 | #define __disarm_kprobe(p) arch_disarm_kprobe(p) |
705 | |
706 | static __kprobes void free_aggr_kprobe(struct kprobe *p) |
707 | { |
708 | kfree(p); |
709 | } |
710 | |
711 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
712 | { |
713 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
714 | } |
715 | #endif /* CONFIG_OPTPROBES */ |
716 | |
717 | /* Arm a kprobe with text_mutex */ |
718 | static void __kprobes arm_kprobe(struct kprobe *kp) |
719 | { |
720 | /* |
721 | * Here, since __arm_kprobe() doesn't use stop_machine(), |
722 | * this doesn't cause deadlock on text_mutex. So, we don't |
723 | * need get_online_cpus(). |
724 | */ |
725 | mutex_lock(&text_mutex); |
726 | __arm_kprobe(kp); |
727 | mutex_unlock(&text_mutex); |
728 | } |
729 | |
730 | /* Disarm a kprobe with text_mutex */ |
731 | static void __kprobes disarm_kprobe(struct kprobe *kp) |
732 | { |
733 | get_online_cpus(); /* For avoiding text_mutex deadlock */ |
734 | mutex_lock(&text_mutex); |
735 | __disarm_kprobe(kp); |
736 | mutex_unlock(&text_mutex); |
737 | put_online_cpus(); |
738 | } |
739 | |
740 | /* |
741 | * Aggregate handlers for multiple kprobes support - these handlers |
742 | * take care of invoking the individual kprobe handlers on p->list |
743 | */ |
744 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
745 | { |
746 | struct kprobe *kp; |
747 | |
748 | list_for_each_entry_rcu(kp, &p->list, list) { |
749 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
750 | set_kprobe_instance(kp); |
751 | if (kp->pre_handler(kp, regs)) |
752 | return 1; |
753 | } |
754 | reset_kprobe_instance(); |
755 | } |
756 | return 0; |
757 | } |
758 | |
759 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
760 | unsigned long flags) |
761 | { |
762 | struct kprobe *kp; |
763 | |
764 | list_for_each_entry_rcu(kp, &p->list, list) { |
765 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
766 | set_kprobe_instance(kp); |
767 | kp->post_handler(kp, regs, flags); |
768 | reset_kprobe_instance(); |
769 | } |
770 | } |
771 | } |
772 | |
773 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
774 | int trapnr) |
775 | { |
776 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
777 | |
778 | /* |
779 | * if we faulted "during" the execution of a user specified |
780 | * probe handler, invoke just that probe's fault handler |
781 | */ |
782 | if (cur && cur->fault_handler) { |
783 | if (cur->fault_handler(cur, regs, trapnr)) |
784 | return 1; |
785 | } |
786 | return 0; |
787 | } |
788 | |
789 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
790 | { |
791 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
792 | int ret = 0; |
793 | |
794 | if (cur && cur->break_handler) { |
795 | if (cur->break_handler(cur, regs)) |
796 | ret = 1; |
797 | } |
798 | reset_kprobe_instance(); |
799 | return ret; |
800 | } |
801 | |
802 | /* Walks the list and increments nmissed count for multiprobe case */ |
803 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) |
804 | { |
805 | struct kprobe *kp; |
806 | if (!kprobe_aggrprobe(p)) { |
807 | p->nmissed++; |
808 | } else { |
809 | list_for_each_entry_rcu(kp, &p->list, list) |
810 | kp->nmissed++; |
811 | } |
812 | return; |
813 | } |
814 | |
815 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
816 | struct hlist_head *head) |
817 | { |
818 | struct kretprobe *rp = ri->rp; |
819 | |
820 | /* remove rp inst off the rprobe_inst_table */ |
821 | hlist_del(&ri->hlist); |
822 | INIT_HLIST_NODE(&ri->hlist); |
823 | if (likely(rp)) { |
824 | spin_lock(&rp->lock); |
825 | hlist_add_head(&ri->hlist, &rp->free_instances); |
826 | spin_unlock(&rp->lock); |
827 | } else |
828 | /* Unregistering */ |
829 | hlist_add_head(&ri->hlist, head); |
830 | } |
831 | |
832 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
833 | struct hlist_head **head, unsigned long *flags) |
834 | { |
835 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
836 | spinlock_t *hlist_lock; |
837 | |
838 | *head = &kretprobe_inst_table[hash]; |
839 | hlist_lock = kretprobe_table_lock_ptr(hash); |
840 | spin_lock_irqsave(hlist_lock, *flags); |
841 | } |
842 | |
843 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
844 | unsigned long *flags) |
845 | { |
846 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
847 | spin_lock_irqsave(hlist_lock, *flags); |
848 | } |
849 | |
850 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
851 | unsigned long *flags) |
852 | { |
853 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
854 | spinlock_t *hlist_lock; |
855 | |
856 | hlist_lock = kretprobe_table_lock_ptr(hash); |
857 | spin_unlock_irqrestore(hlist_lock, *flags); |
858 | } |
859 | |
860 | void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags) |
861 | { |
862 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
863 | spin_unlock_irqrestore(hlist_lock, *flags); |
864 | } |
865 | |
866 | /* |
867 | * This function is called from finish_task_switch when task tk becomes dead, |
868 | * so that we can recycle any function-return probe instances associated |
869 | * with this task. These left over instances represent probed functions |
870 | * that have been called but will never return. |
871 | */ |
872 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
873 | { |
874 | struct kretprobe_instance *ri; |
875 | struct hlist_head *head, empty_rp; |
876 | struct hlist_node *node, *tmp; |
877 | unsigned long hash, flags = 0; |
878 | |
879 | if (unlikely(!kprobes_initialized)) |
880 | /* Early boot. kretprobe_table_locks not yet initialized. */ |
881 | return; |
882 | |
883 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
884 | head = &kretprobe_inst_table[hash]; |
885 | kretprobe_table_lock(hash, &flags); |
886 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
887 | if (ri->task == tk) |
888 | recycle_rp_inst(ri, &empty_rp); |
889 | } |
890 | kretprobe_table_unlock(hash, &flags); |
891 | INIT_HLIST_HEAD(&empty_rp); |
892 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
893 | hlist_del(&ri->hlist); |
894 | kfree(ri); |
895 | } |
896 | } |
897 | |
898 | static inline void free_rp_inst(struct kretprobe *rp) |
899 | { |
900 | struct kretprobe_instance *ri; |
901 | struct hlist_node *pos, *next; |
902 | |
903 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
904 | hlist_del(&ri->hlist); |
905 | kfree(ri); |
906 | } |
907 | } |
908 | |
909 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
910 | { |
911 | unsigned long flags, hash; |
912 | struct kretprobe_instance *ri; |
913 | struct hlist_node *pos, *next; |
914 | struct hlist_head *head; |
915 | |
916 | /* No race here */ |
917 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
918 | kretprobe_table_lock(hash, &flags); |
919 | head = &kretprobe_inst_table[hash]; |
920 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { |
921 | if (ri->rp == rp) |
922 | ri->rp = NULL; |
923 | } |
924 | kretprobe_table_unlock(hash, &flags); |
925 | } |
926 | free_rp_inst(rp); |
927 | } |
928 | |
929 | /* |
930 | * Add the new probe to ap->list. Fail if this is the |
931 | * second jprobe at the address - two jprobes can't coexist |
932 | */ |
933 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
934 | { |
935 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
936 | |
937 | if (p->break_handler || p->post_handler) |
938 | unoptimize_kprobe(ap); /* Fall back to normal kprobe */ |
939 | |
940 | if (p->break_handler) { |
941 | if (ap->break_handler) |
942 | return -EEXIST; |
943 | list_add_tail_rcu(&p->list, &ap->list); |
944 | ap->break_handler = aggr_break_handler; |
945 | } else |
946 | list_add_rcu(&p->list, &ap->list); |
947 | if (p->post_handler && !ap->post_handler) |
948 | ap->post_handler = aggr_post_handler; |
949 | |
950 | if (kprobe_disabled(ap) && !kprobe_disabled(p)) { |
951 | ap->flags &= ~KPROBE_FLAG_DISABLED; |
952 | if (!kprobes_all_disarmed) |
953 | /* Arm the breakpoint again. */ |
954 | __arm_kprobe(ap); |
955 | } |
956 | return 0; |
957 | } |
958 | |
959 | /* |
960 | * Fill in the required fields of the "manager kprobe". Replace the |
961 | * earlier kprobe in the hlist with the manager kprobe |
962 | */ |
963 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
964 | { |
965 | /* Copy p's insn slot to ap */ |
966 | copy_kprobe(p, ap); |
967 | flush_insn_slot(ap); |
968 | ap->addr = p->addr; |
969 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
970 | ap->pre_handler = aggr_pre_handler; |
971 | ap->fault_handler = aggr_fault_handler; |
972 | /* We don't care the kprobe which has gone. */ |
973 | if (p->post_handler && !kprobe_gone(p)) |
974 | ap->post_handler = aggr_post_handler; |
975 | if (p->break_handler && !kprobe_gone(p)) |
976 | ap->break_handler = aggr_break_handler; |
977 | |
978 | INIT_LIST_HEAD(&ap->list); |
979 | INIT_HLIST_NODE(&ap->hlist); |
980 | |
981 | list_add_rcu(&p->list, &ap->list); |
982 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
983 | } |
984 | |
985 | /* |
986 | * This is the second or subsequent kprobe at the address - handle |
987 | * the intricacies |
988 | */ |
989 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
990 | struct kprobe *p) |
991 | { |
992 | int ret = 0; |
993 | struct kprobe *ap = old_p; |
994 | |
995 | if (!kprobe_aggrprobe(old_p)) { |
996 | /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */ |
997 | ap = alloc_aggr_kprobe(old_p); |
998 | if (!ap) |
999 | return -ENOMEM; |
1000 | init_aggr_kprobe(ap, old_p); |
1001 | } |
1002 | |
1003 | if (kprobe_gone(ap)) { |
1004 | /* |
1005 | * Attempting to insert new probe at the same location that |
1006 | * had a probe in the module vaddr area which already |
1007 | * freed. So, the instruction slot has already been |
1008 | * released. We need a new slot for the new probe. |
1009 | */ |
1010 | ret = arch_prepare_kprobe(ap); |
1011 | if (ret) |
1012 | /* |
1013 | * Even if fail to allocate new slot, don't need to |
1014 | * free aggr_probe. It will be used next time, or |
1015 | * freed by unregister_kprobe. |
1016 | */ |
1017 | return ret; |
1018 | |
1019 | /* Prepare optimized instructions if possible. */ |
1020 | prepare_optimized_kprobe(ap); |
1021 | |
1022 | /* |
1023 | * Clear gone flag to prevent allocating new slot again, and |
1024 | * set disabled flag because it is not armed yet. |
1025 | */ |
1026 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1027 | | KPROBE_FLAG_DISABLED; |
1028 | } |
1029 | |
1030 | /* Copy ap's insn slot to p */ |
1031 | copy_kprobe(ap, p); |
1032 | return add_new_kprobe(ap, p); |
1033 | } |
1034 | |
1035 | /* Try to disable aggr_kprobe, and return 1 if succeeded.*/ |
1036 | static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p) |
1037 | { |
1038 | struct kprobe *kp; |
1039 | |
1040 | list_for_each_entry_rcu(kp, &p->list, list) { |
1041 | if (!kprobe_disabled(kp)) |
1042 | /* |
1043 | * There is an active probe on the list. |
1044 | * We can't disable aggr_kprobe. |
1045 | */ |
1046 | return 0; |
1047 | } |
1048 | p->flags |= KPROBE_FLAG_DISABLED; |
1049 | return 1; |
1050 | } |
1051 | |
1052 | static int __kprobes in_kprobes_functions(unsigned long addr) |
1053 | { |
1054 | struct kprobe_blackpoint *kb; |
1055 | |
1056 | if (addr >= (unsigned long)__kprobes_text_start && |
1057 | addr < (unsigned long)__kprobes_text_end) |
1058 | return -EINVAL; |
1059 | /* |
1060 | * If there exists a kprobe_blacklist, verify and |
1061 | * fail any probe registration in the prohibited area |
1062 | */ |
1063 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
1064 | if (kb->start_addr) { |
1065 | if (addr >= kb->start_addr && |
1066 | addr < (kb->start_addr + kb->range)) |
1067 | return -EINVAL; |
1068 | } |
1069 | } |
1070 | return 0; |
1071 | } |
1072 | |
1073 | /* |
1074 | * If we have a symbol_name argument, look it up and add the offset field |
1075 | * to it. This way, we can specify a relative address to a symbol. |
1076 | */ |
1077 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) |
1078 | { |
1079 | kprobe_opcode_t *addr = p->addr; |
1080 | if (p->symbol_name) { |
1081 | if (addr) |
1082 | return NULL; |
1083 | kprobe_lookup_name(p->symbol_name, addr); |
1084 | } |
1085 | |
1086 | if (!addr) |
1087 | return NULL; |
1088 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); |
1089 | } |
1090 | |
1091 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1092 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) |
1093 | { |
1094 | struct kprobe *old_p, *list_p; |
1095 | |
1096 | old_p = get_kprobe(p->addr); |
1097 | if (unlikely(!old_p)) |
1098 | return NULL; |
1099 | |
1100 | if (p != old_p) { |
1101 | list_for_each_entry_rcu(list_p, &old_p->list, list) |
1102 | if (list_p == p) |
1103 | /* kprobe p is a valid probe */ |
1104 | goto valid; |
1105 | return NULL; |
1106 | } |
1107 | valid: |
1108 | return old_p; |
1109 | } |
1110 | |
1111 | /* Return error if the kprobe is being re-registered */ |
1112 | static inline int check_kprobe_rereg(struct kprobe *p) |
1113 | { |
1114 | int ret = 0; |
1115 | struct kprobe *old_p; |
1116 | |
1117 | mutex_lock(&kprobe_mutex); |
1118 | old_p = __get_valid_kprobe(p); |
1119 | if (old_p) |
1120 | ret = -EINVAL; |
1121 | mutex_unlock(&kprobe_mutex); |
1122 | return ret; |
1123 | } |
1124 | |
1125 | int __kprobes register_kprobe(struct kprobe *p) |
1126 | { |
1127 | int ret = 0; |
1128 | struct kprobe *old_p; |
1129 | struct module *probed_mod; |
1130 | kprobe_opcode_t *addr; |
1131 | |
1132 | addr = kprobe_addr(p); |
1133 | if (!addr) |
1134 | return -EINVAL; |
1135 | p->addr = addr; |
1136 | |
1137 | ret = check_kprobe_rereg(p); |
1138 | if (ret) |
1139 | return ret; |
1140 | |
1141 | preempt_disable(); |
1142 | if (!kernel_text_address((unsigned long) p->addr) || |
1143 | in_kprobes_functions((unsigned long) p->addr) || |
1144 | ftrace_text_reserved(p->addr, p->addr)) { |
1145 | preempt_enable(); |
1146 | return -EINVAL; |
1147 | } |
1148 | |
1149 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
1150 | p->flags &= KPROBE_FLAG_DISABLED; |
1151 | |
1152 | /* |
1153 | * Check if are we probing a module. |
1154 | */ |
1155 | probed_mod = __module_text_address((unsigned long) p->addr); |
1156 | if (probed_mod) { |
1157 | /* |
1158 | * We must hold a refcount of the probed module while updating |
1159 | * its code to prohibit unexpected unloading. |
1160 | */ |
1161 | if (unlikely(!try_module_get(probed_mod))) { |
1162 | preempt_enable(); |
1163 | return -EINVAL; |
1164 | } |
1165 | /* |
1166 | * If the module freed .init.text, we couldn't insert |
1167 | * kprobes in there. |
1168 | */ |
1169 | if (within_module_init((unsigned long)p->addr, probed_mod) && |
1170 | probed_mod->state != MODULE_STATE_COMING) { |
1171 | module_put(probed_mod); |
1172 | preempt_enable(); |
1173 | return -EINVAL; |
1174 | } |
1175 | } |
1176 | preempt_enable(); |
1177 | |
1178 | p->nmissed = 0; |
1179 | INIT_LIST_HEAD(&p->list); |
1180 | mutex_lock(&kprobe_mutex); |
1181 | |
1182 | get_online_cpus(); /* For avoiding text_mutex deadlock. */ |
1183 | mutex_lock(&text_mutex); |
1184 | |
1185 | old_p = get_kprobe(p->addr); |
1186 | if (old_p) { |
1187 | /* Since this may unoptimize old_p, locking text_mutex. */ |
1188 | ret = register_aggr_kprobe(old_p, p); |
1189 | goto out; |
1190 | } |
1191 | |
1192 | ret = arch_prepare_kprobe(p); |
1193 | if (ret) |
1194 | goto out; |
1195 | |
1196 | INIT_HLIST_NODE(&p->hlist); |
1197 | hlist_add_head_rcu(&p->hlist, |
1198 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1199 | |
1200 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
1201 | __arm_kprobe(p); |
1202 | |
1203 | /* Try to optimize kprobe */ |
1204 | try_to_optimize_kprobe(p); |
1205 | |
1206 | out: |
1207 | mutex_unlock(&text_mutex); |
1208 | put_online_cpus(); |
1209 | mutex_unlock(&kprobe_mutex); |
1210 | |
1211 | if (probed_mod) |
1212 | module_put(probed_mod); |
1213 | |
1214 | return ret; |
1215 | } |
1216 | EXPORT_SYMBOL_GPL(register_kprobe); |
1217 | |
1218 | /* |
1219 | * Unregister a kprobe without a scheduler synchronization. |
1220 | */ |
1221 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) |
1222 | { |
1223 | struct kprobe *old_p, *list_p; |
1224 | |
1225 | old_p = __get_valid_kprobe(p); |
1226 | if (old_p == NULL) |
1227 | return -EINVAL; |
1228 | |
1229 | if (old_p == p || |
1230 | (kprobe_aggrprobe(old_p) && |
1231 | list_is_singular(&old_p->list))) { |
1232 | /* |
1233 | * Only probe on the hash list. Disarm only if kprobes are |
1234 | * enabled and not gone - otherwise, the breakpoint would |
1235 | * already have been removed. We save on flushing icache. |
1236 | */ |
1237 | if (!kprobes_all_disarmed && !kprobe_disabled(old_p)) |
1238 | disarm_kprobe(old_p); |
1239 | hlist_del_rcu(&old_p->hlist); |
1240 | } else { |
1241 | if (p->break_handler && !kprobe_gone(p)) |
1242 | old_p->break_handler = NULL; |
1243 | if (p->post_handler && !kprobe_gone(p)) { |
1244 | list_for_each_entry_rcu(list_p, &old_p->list, list) { |
1245 | if ((list_p != p) && (list_p->post_handler)) |
1246 | goto noclean; |
1247 | } |
1248 | old_p->post_handler = NULL; |
1249 | } |
1250 | noclean: |
1251 | list_del_rcu(&p->list); |
1252 | if (!kprobe_disabled(old_p)) { |
1253 | try_to_disable_aggr_kprobe(old_p); |
1254 | if (!kprobes_all_disarmed) { |
1255 | if (kprobe_disabled(old_p)) |
1256 | disarm_kprobe(old_p); |
1257 | else |
1258 | /* Try to optimize this probe again */ |
1259 | optimize_kprobe(old_p); |
1260 | } |
1261 | } |
1262 | } |
1263 | return 0; |
1264 | } |
1265 | |
1266 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
1267 | { |
1268 | struct kprobe *old_p; |
1269 | |
1270 | if (list_empty(&p->list)) |
1271 | arch_remove_kprobe(p); |
1272 | else if (list_is_singular(&p->list)) { |
1273 | /* "p" is the last child of an aggr_kprobe */ |
1274 | old_p = list_entry(p->list.next, struct kprobe, list); |
1275 | list_del(&p->list); |
1276 | arch_remove_kprobe(old_p); |
1277 | free_aggr_kprobe(old_p); |
1278 | } |
1279 | } |
1280 | |
1281 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
1282 | { |
1283 | int i, ret = 0; |
1284 | |
1285 | if (num <= 0) |
1286 | return -EINVAL; |
1287 | for (i = 0; i < num; i++) { |
1288 | ret = register_kprobe(kps[i]); |
1289 | if (ret < 0) { |
1290 | if (i > 0) |
1291 | unregister_kprobes(kps, i); |
1292 | break; |
1293 | } |
1294 | } |
1295 | return ret; |
1296 | } |
1297 | EXPORT_SYMBOL_GPL(register_kprobes); |
1298 | |
1299 | void __kprobes unregister_kprobe(struct kprobe *p) |
1300 | { |
1301 | unregister_kprobes(&p, 1); |
1302 | } |
1303 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
1304 | |
1305 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
1306 | { |
1307 | int i; |
1308 | |
1309 | if (num <= 0) |
1310 | return; |
1311 | mutex_lock(&kprobe_mutex); |
1312 | for (i = 0; i < num; i++) |
1313 | if (__unregister_kprobe_top(kps[i]) < 0) |
1314 | kps[i]->addr = NULL; |
1315 | mutex_unlock(&kprobe_mutex); |
1316 | |
1317 | synchronize_sched(); |
1318 | for (i = 0; i < num; i++) |
1319 | if (kps[i]->addr) |
1320 | __unregister_kprobe_bottom(kps[i]); |
1321 | } |
1322 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1323 | |
1324 | static struct notifier_block kprobe_exceptions_nb = { |
1325 | .notifier_call = kprobe_exceptions_notify, |
1326 | .priority = 0x7fffffff /* we need to be notified first */ |
1327 | }; |
1328 | |
1329 | unsigned long __weak arch_deref_entry_point(void *entry) |
1330 | { |
1331 | return (unsigned long)entry; |
1332 | } |
1333 | |
1334 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1335 | { |
1336 | struct jprobe *jp; |
1337 | int ret = 0, i; |
1338 | |
1339 | if (num <= 0) |
1340 | return -EINVAL; |
1341 | for (i = 0; i < num; i++) { |
1342 | unsigned long addr; |
1343 | jp = jps[i]; |
1344 | addr = arch_deref_entry_point(jp->entry); |
1345 | |
1346 | if (!kernel_text_address(addr)) |
1347 | ret = -EINVAL; |
1348 | else { |
1349 | /* Todo: Verify probepoint is a function entry point */ |
1350 | jp->kp.pre_handler = setjmp_pre_handler; |
1351 | jp->kp.break_handler = longjmp_break_handler; |
1352 | ret = register_kprobe(&jp->kp); |
1353 | } |
1354 | if (ret < 0) { |
1355 | if (i > 0) |
1356 | unregister_jprobes(jps, i); |
1357 | break; |
1358 | } |
1359 | } |
1360 | return ret; |
1361 | } |
1362 | EXPORT_SYMBOL_GPL(register_jprobes); |
1363 | |
1364 | int __kprobes register_jprobe(struct jprobe *jp) |
1365 | { |
1366 | return register_jprobes(&jp, 1); |
1367 | } |
1368 | EXPORT_SYMBOL_GPL(register_jprobe); |
1369 | |
1370 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1371 | { |
1372 | unregister_jprobes(&jp, 1); |
1373 | } |
1374 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
1375 | |
1376 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
1377 | { |
1378 | int i; |
1379 | |
1380 | if (num <= 0) |
1381 | return; |
1382 | mutex_lock(&kprobe_mutex); |
1383 | for (i = 0; i < num; i++) |
1384 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) |
1385 | jps[i]->kp.addr = NULL; |
1386 | mutex_unlock(&kprobe_mutex); |
1387 | |
1388 | synchronize_sched(); |
1389 | for (i = 0; i < num; i++) { |
1390 | if (jps[i]->kp.addr) |
1391 | __unregister_kprobe_bottom(&jps[i]->kp); |
1392 | } |
1393 | } |
1394 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1395 | |
1396 | #ifdef CONFIG_KRETPROBES |
1397 | /* |
1398 | * This kprobe pre_handler is registered with every kretprobe. When probe |
1399 | * hits it will set up the return probe. |
1400 | */ |
1401 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1402 | struct pt_regs *regs) |
1403 | { |
1404 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
1405 | unsigned long hash, flags = 0; |
1406 | struct kretprobe_instance *ri; |
1407 | |
1408 | /*TODO: consider to only swap the RA after the last pre_handler fired */ |
1409 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
1410 | spin_lock_irqsave(&rp->lock, flags); |
1411 | if (!hlist_empty(&rp->free_instances)) { |
1412 | ri = hlist_entry(rp->free_instances.first, |
1413 | struct kretprobe_instance, hlist); |
1414 | hlist_del(&ri->hlist); |
1415 | spin_unlock_irqrestore(&rp->lock, flags); |
1416 | |
1417 | ri->rp = rp; |
1418 | ri->task = current; |
1419 | |
1420 | if (rp->entry_handler && rp->entry_handler(ri, regs)) |
1421 | return 0; |
1422 | |
1423 | arch_prepare_kretprobe(ri, regs); |
1424 | |
1425 | /* XXX(hch): why is there no hlist_move_head? */ |
1426 | INIT_HLIST_NODE(&ri->hlist); |
1427 | kretprobe_table_lock(hash, &flags); |
1428 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); |
1429 | kretprobe_table_unlock(hash, &flags); |
1430 | } else { |
1431 | rp->nmissed++; |
1432 | spin_unlock_irqrestore(&rp->lock, flags); |
1433 | } |
1434 | return 0; |
1435 | } |
1436 | |
1437 | int __kprobes register_kretprobe(struct kretprobe *rp) |
1438 | { |
1439 | int ret = 0; |
1440 | struct kretprobe_instance *inst; |
1441 | int i; |
1442 | void *addr; |
1443 | |
1444 | if (kretprobe_blacklist_size) { |
1445 | addr = kprobe_addr(&rp->kp); |
1446 | if (!addr) |
1447 | return -EINVAL; |
1448 | |
1449 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1450 | if (kretprobe_blacklist[i].addr == addr) |
1451 | return -EINVAL; |
1452 | } |
1453 | } |
1454 | |
1455 | rp->kp.pre_handler = pre_handler_kretprobe; |
1456 | rp->kp.post_handler = NULL; |
1457 | rp->kp.fault_handler = NULL; |
1458 | rp->kp.break_handler = NULL; |
1459 | |
1460 | /* Pre-allocate memory for max kretprobe instances */ |
1461 | if (rp->maxactive <= 0) { |
1462 | #ifdef CONFIG_PREEMPT |
1463 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
1464 | #else |
1465 | rp->maxactive = num_possible_cpus(); |
1466 | #endif |
1467 | } |
1468 | spin_lock_init(&rp->lock); |
1469 | INIT_HLIST_HEAD(&rp->free_instances); |
1470 | for (i = 0; i < rp->maxactive; i++) { |
1471 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1472 | rp->data_size, GFP_KERNEL); |
1473 | if (inst == NULL) { |
1474 | free_rp_inst(rp); |
1475 | return -ENOMEM; |
1476 | } |
1477 | INIT_HLIST_NODE(&inst->hlist); |
1478 | hlist_add_head(&inst->hlist, &rp->free_instances); |
1479 | } |
1480 | |
1481 | rp->nmissed = 0; |
1482 | /* Establish function entry probe point */ |
1483 | ret = register_kprobe(&rp->kp); |
1484 | if (ret != 0) |
1485 | free_rp_inst(rp); |
1486 | return ret; |
1487 | } |
1488 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1489 | |
1490 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
1491 | { |
1492 | int ret = 0, i; |
1493 | |
1494 | if (num <= 0) |
1495 | return -EINVAL; |
1496 | for (i = 0; i < num; i++) { |
1497 | ret = register_kretprobe(rps[i]); |
1498 | if (ret < 0) { |
1499 | if (i > 0) |
1500 | unregister_kretprobes(rps, i); |
1501 | break; |
1502 | } |
1503 | } |
1504 | return ret; |
1505 | } |
1506 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1507 | |
1508 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1509 | { |
1510 | unregister_kretprobes(&rp, 1); |
1511 | } |
1512 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1513 | |
1514 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1515 | { |
1516 | int i; |
1517 | |
1518 | if (num <= 0) |
1519 | return; |
1520 | mutex_lock(&kprobe_mutex); |
1521 | for (i = 0; i < num; i++) |
1522 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
1523 | rps[i]->kp.addr = NULL; |
1524 | mutex_unlock(&kprobe_mutex); |
1525 | |
1526 | synchronize_sched(); |
1527 | for (i = 0; i < num; i++) { |
1528 | if (rps[i]->kp.addr) { |
1529 | __unregister_kprobe_bottom(&rps[i]->kp); |
1530 | cleanup_rp_inst(rps[i]); |
1531 | } |
1532 | } |
1533 | } |
1534 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1535 | |
1536 | #else /* CONFIG_KRETPROBES */ |
1537 | int __kprobes register_kretprobe(struct kretprobe *rp) |
1538 | { |
1539 | return -ENOSYS; |
1540 | } |
1541 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1542 | |
1543 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
1544 | { |
1545 | return -ENOSYS; |
1546 | } |
1547 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1548 | |
1549 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1550 | { |
1551 | } |
1552 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1553 | |
1554 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1555 | { |
1556 | } |
1557 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1558 | |
1559 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1560 | struct pt_regs *regs) |
1561 | { |
1562 | return 0; |
1563 | } |
1564 | |
1565 | #endif /* CONFIG_KRETPROBES */ |
1566 | |
1567 | /* Set the kprobe gone and remove its instruction buffer. */ |
1568 | static void __kprobes kill_kprobe(struct kprobe *p) |
1569 | { |
1570 | struct kprobe *kp; |
1571 | |
1572 | p->flags |= KPROBE_FLAG_GONE; |
1573 | if (kprobe_aggrprobe(p)) { |
1574 | /* |
1575 | * If this is an aggr_kprobe, we have to list all the |
1576 | * chained probes and mark them GONE. |
1577 | */ |
1578 | list_for_each_entry_rcu(kp, &p->list, list) |
1579 | kp->flags |= KPROBE_FLAG_GONE; |
1580 | p->post_handler = NULL; |
1581 | p->break_handler = NULL; |
1582 | kill_optimized_kprobe(p); |
1583 | } |
1584 | /* |
1585 | * Here, we can remove insn_slot safely, because no thread calls |
1586 | * the original probed function (which will be freed soon) any more. |
1587 | */ |
1588 | arch_remove_kprobe(p); |
1589 | } |
1590 | |
1591 | void __kprobes dump_kprobe(struct kprobe *kp) |
1592 | { |
1593 | printk(KERN_WARNING "Dumping kprobe:\n"); |
1594 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", |
1595 | kp->symbol_name, kp->addr, kp->offset); |
1596 | } |
1597 | |
1598 | /* Module notifier call back, checking kprobes on the module */ |
1599 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, |
1600 | unsigned long val, void *data) |
1601 | { |
1602 | struct module *mod = data; |
1603 | struct hlist_head *head; |
1604 | struct hlist_node *node; |
1605 | struct kprobe *p; |
1606 | unsigned int i; |
1607 | int checkcore = (val == MODULE_STATE_GOING); |
1608 | |
1609 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
1610 | return NOTIFY_DONE; |
1611 | |
1612 | /* |
1613 | * When MODULE_STATE_GOING was notified, both of module .text and |
1614 | * .init.text sections would be freed. When MODULE_STATE_LIVE was |
1615 | * notified, only .init.text section would be freed. We need to |
1616 | * disable kprobes which have been inserted in the sections. |
1617 | */ |
1618 | mutex_lock(&kprobe_mutex); |
1619 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1620 | head = &kprobe_table[i]; |
1621 | hlist_for_each_entry_rcu(p, node, head, hlist) |
1622 | if (within_module_init((unsigned long)p->addr, mod) || |
1623 | (checkcore && |
1624 | within_module_core((unsigned long)p->addr, mod))) { |
1625 | /* |
1626 | * The vaddr this probe is installed will soon |
1627 | * be vfreed buy not synced to disk. Hence, |
1628 | * disarming the breakpoint isn't needed. |
1629 | */ |
1630 | kill_kprobe(p); |
1631 | } |
1632 | } |
1633 | mutex_unlock(&kprobe_mutex); |
1634 | return NOTIFY_DONE; |
1635 | } |
1636 | |
1637 | static struct notifier_block kprobe_module_nb = { |
1638 | .notifier_call = kprobes_module_callback, |
1639 | .priority = 0 |
1640 | }; |
1641 | |
1642 | static int __init init_kprobes(void) |
1643 | { |
1644 | int i, err = 0; |
1645 | unsigned long offset = 0, size = 0; |
1646 | char *modname, namebuf[128]; |
1647 | const char *symbol_name; |
1648 | void *addr; |
1649 | struct kprobe_blackpoint *kb; |
1650 | |
1651 | /* FIXME allocate the probe table, currently defined statically */ |
1652 | /* initialize all list heads */ |
1653 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1654 | INIT_HLIST_HEAD(&kprobe_table[i]); |
1655 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
1656 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
1657 | } |
1658 | |
1659 | /* |
1660 | * Lookup and populate the kprobe_blacklist. |
1661 | * |
1662 | * Unlike the kretprobe blacklist, we'll need to determine |
1663 | * the range of addresses that belong to the said functions, |
1664 | * since a kprobe need not necessarily be at the beginning |
1665 | * of a function. |
1666 | */ |
1667 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
1668 | kprobe_lookup_name(kb->name, addr); |
1669 | if (!addr) |
1670 | continue; |
1671 | |
1672 | kb->start_addr = (unsigned long)addr; |
1673 | symbol_name = kallsyms_lookup(kb->start_addr, |
1674 | &size, &offset, &modname, namebuf); |
1675 | if (!symbol_name) |
1676 | kb->range = 0; |
1677 | else |
1678 | kb->range = size; |
1679 | } |
1680 | |
1681 | if (kretprobe_blacklist_size) { |
1682 | /* lookup the function address from its name */ |
1683 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1684 | kprobe_lookup_name(kretprobe_blacklist[i].name, |
1685 | kretprobe_blacklist[i].addr); |
1686 | if (!kretprobe_blacklist[i].addr) |
1687 | printk("kretprobe: lookup failed: %s\n", |
1688 | kretprobe_blacklist[i].name); |
1689 | } |
1690 | } |
1691 | |
1692 | #if defined(CONFIG_OPTPROBES) |
1693 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
1694 | /* Init kprobe_optinsn_slots */ |
1695 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
1696 | #endif |
1697 | /* By default, kprobes can be optimized */ |
1698 | kprobes_allow_optimization = true; |
1699 | #endif |
1700 | |
1701 | /* By default, kprobes are armed */ |
1702 | kprobes_all_disarmed = false; |
1703 | |
1704 | err = arch_init_kprobes(); |
1705 | if (!err) |
1706 | err = register_die_notifier(&kprobe_exceptions_nb); |
1707 | if (!err) |
1708 | err = register_module_notifier(&kprobe_module_nb); |
1709 | |
1710 | kprobes_initialized = (err == 0); |
1711 | |
1712 | if (!err) |
1713 | init_test_probes(); |
1714 | return err; |
1715 | } |
1716 | |
1717 | #ifdef CONFIG_DEBUG_FS |
1718 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, |
1719 | const char *sym, int offset, char *modname, struct kprobe *pp) |
1720 | { |
1721 | char *kprobe_type; |
1722 | |
1723 | if (p->pre_handler == pre_handler_kretprobe) |
1724 | kprobe_type = "r"; |
1725 | else if (p->pre_handler == setjmp_pre_handler) |
1726 | kprobe_type = "j"; |
1727 | else |
1728 | kprobe_type = "k"; |
1729 | |
1730 | if (sym) |
1731 | seq_printf(pi, "%p %s %s+0x%x %s ", |
1732 | p->addr, kprobe_type, sym, offset, |
1733 | (modname ? modname : " ")); |
1734 | else |
1735 | seq_printf(pi, "%p %s %p ", |
1736 | p->addr, kprobe_type, p->addr); |
1737 | |
1738 | if (!pp) |
1739 | pp = p; |
1740 | seq_printf(pi, "%s%s%s\n", |
1741 | (kprobe_gone(p) ? "[GONE]" : ""), |
1742 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), |
1743 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : "")); |
1744 | } |
1745 | |
1746 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
1747 | { |
1748 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; |
1749 | } |
1750 | |
1751 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
1752 | { |
1753 | (*pos)++; |
1754 | if (*pos >= KPROBE_TABLE_SIZE) |
1755 | return NULL; |
1756 | return pos; |
1757 | } |
1758 | |
1759 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) |
1760 | { |
1761 | /* Nothing to do */ |
1762 | } |
1763 | |
1764 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) |
1765 | { |
1766 | struct hlist_head *head; |
1767 | struct hlist_node *node; |
1768 | struct kprobe *p, *kp; |
1769 | const char *sym = NULL; |
1770 | unsigned int i = *(loff_t *) v; |
1771 | unsigned long offset = 0; |
1772 | char *modname, namebuf[128]; |
1773 | |
1774 | head = &kprobe_table[i]; |
1775 | preempt_disable(); |
1776 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1777 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
1778 | &offset, &modname, namebuf); |
1779 | if (kprobe_aggrprobe(p)) { |
1780 | list_for_each_entry_rcu(kp, &p->list, list) |
1781 | report_probe(pi, kp, sym, offset, modname, p); |
1782 | } else |
1783 | report_probe(pi, p, sym, offset, modname, NULL); |
1784 | } |
1785 | preempt_enable(); |
1786 | return 0; |
1787 | } |
1788 | |
1789 | static const struct seq_operations kprobes_seq_ops = { |
1790 | .start = kprobe_seq_start, |
1791 | .next = kprobe_seq_next, |
1792 | .stop = kprobe_seq_stop, |
1793 | .show = show_kprobe_addr |
1794 | }; |
1795 | |
1796 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) |
1797 | { |
1798 | return seq_open(filp, &kprobes_seq_ops); |
1799 | } |
1800 | |
1801 | static const struct file_operations debugfs_kprobes_operations = { |
1802 | .open = kprobes_open, |
1803 | .read = seq_read, |
1804 | .llseek = seq_lseek, |
1805 | .release = seq_release, |
1806 | }; |
1807 | |
1808 | /* Disable one kprobe */ |
1809 | int __kprobes disable_kprobe(struct kprobe *kp) |
1810 | { |
1811 | int ret = 0; |
1812 | struct kprobe *p; |
1813 | |
1814 | mutex_lock(&kprobe_mutex); |
1815 | |
1816 | /* Check whether specified probe is valid. */ |
1817 | p = __get_valid_kprobe(kp); |
1818 | if (unlikely(p == NULL)) { |
1819 | ret = -EINVAL; |
1820 | goto out; |
1821 | } |
1822 | |
1823 | /* If the probe is already disabled (or gone), just return */ |
1824 | if (kprobe_disabled(kp)) |
1825 | goto out; |
1826 | |
1827 | kp->flags |= KPROBE_FLAG_DISABLED; |
1828 | if (p != kp) |
1829 | /* When kp != p, p is always enabled. */ |
1830 | try_to_disable_aggr_kprobe(p); |
1831 | |
1832 | if (!kprobes_all_disarmed && kprobe_disabled(p)) |
1833 | disarm_kprobe(p); |
1834 | out: |
1835 | mutex_unlock(&kprobe_mutex); |
1836 | return ret; |
1837 | } |
1838 | EXPORT_SYMBOL_GPL(disable_kprobe); |
1839 | |
1840 | /* Enable one kprobe */ |
1841 | int __kprobes enable_kprobe(struct kprobe *kp) |
1842 | { |
1843 | int ret = 0; |
1844 | struct kprobe *p; |
1845 | |
1846 | mutex_lock(&kprobe_mutex); |
1847 | |
1848 | /* Check whether specified probe is valid. */ |
1849 | p = __get_valid_kprobe(kp); |
1850 | if (unlikely(p == NULL)) { |
1851 | ret = -EINVAL; |
1852 | goto out; |
1853 | } |
1854 | |
1855 | if (kprobe_gone(kp)) { |
1856 | /* This kprobe has gone, we couldn't enable it. */ |
1857 | ret = -EINVAL; |
1858 | goto out; |
1859 | } |
1860 | |
1861 | if (p != kp) |
1862 | kp->flags &= ~KPROBE_FLAG_DISABLED; |
1863 | |
1864 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { |
1865 | p->flags &= ~KPROBE_FLAG_DISABLED; |
1866 | arm_kprobe(p); |
1867 | } |
1868 | out: |
1869 | mutex_unlock(&kprobe_mutex); |
1870 | return ret; |
1871 | } |
1872 | EXPORT_SYMBOL_GPL(enable_kprobe); |
1873 | |
1874 | static void __kprobes arm_all_kprobes(void) |
1875 | { |
1876 | struct hlist_head *head; |
1877 | struct hlist_node *node; |
1878 | struct kprobe *p; |
1879 | unsigned int i; |
1880 | |
1881 | mutex_lock(&kprobe_mutex); |
1882 | |
1883 | /* If kprobes are armed, just return */ |
1884 | if (!kprobes_all_disarmed) |
1885 | goto already_enabled; |
1886 | |
1887 | /* Arming kprobes doesn't optimize kprobe itself */ |
1888 | mutex_lock(&text_mutex); |
1889 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1890 | head = &kprobe_table[i]; |
1891 | hlist_for_each_entry_rcu(p, node, head, hlist) |
1892 | if (!kprobe_disabled(p)) |
1893 | __arm_kprobe(p); |
1894 | } |
1895 | mutex_unlock(&text_mutex); |
1896 | |
1897 | kprobes_all_disarmed = false; |
1898 | printk(KERN_INFO "Kprobes globally enabled\n"); |
1899 | |
1900 | already_enabled: |
1901 | mutex_unlock(&kprobe_mutex); |
1902 | return; |
1903 | } |
1904 | |
1905 | static void __kprobes disarm_all_kprobes(void) |
1906 | { |
1907 | struct hlist_head *head; |
1908 | struct hlist_node *node; |
1909 | struct kprobe *p; |
1910 | unsigned int i; |
1911 | |
1912 | mutex_lock(&kprobe_mutex); |
1913 | |
1914 | /* If kprobes are already disarmed, just return */ |
1915 | if (kprobes_all_disarmed) |
1916 | goto already_disabled; |
1917 | |
1918 | kprobes_all_disarmed = true; |
1919 | printk(KERN_INFO "Kprobes globally disabled\n"); |
1920 | |
1921 | /* |
1922 | * Here we call get_online_cpus() for avoiding text_mutex deadlock, |
1923 | * because disarming may also unoptimize kprobes. |
1924 | */ |
1925 | get_online_cpus(); |
1926 | mutex_lock(&text_mutex); |
1927 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1928 | head = &kprobe_table[i]; |
1929 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1930 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
1931 | __disarm_kprobe(p); |
1932 | } |
1933 | } |
1934 | |
1935 | mutex_unlock(&text_mutex); |
1936 | put_online_cpus(); |
1937 | mutex_unlock(&kprobe_mutex); |
1938 | /* Allow all currently running kprobes to complete */ |
1939 | synchronize_sched(); |
1940 | return; |
1941 | |
1942 | already_disabled: |
1943 | mutex_unlock(&kprobe_mutex); |
1944 | return; |
1945 | } |
1946 | |
1947 | /* |
1948 | * XXX: The debugfs bool file interface doesn't allow for callbacks |
1949 | * when the bool state is switched. We can reuse that facility when |
1950 | * available |
1951 | */ |
1952 | static ssize_t read_enabled_file_bool(struct file *file, |
1953 | char __user *user_buf, size_t count, loff_t *ppos) |
1954 | { |
1955 | char buf[3]; |
1956 | |
1957 | if (!kprobes_all_disarmed) |
1958 | buf[0] = '1'; |
1959 | else |
1960 | buf[0] = '0'; |
1961 | buf[1] = '\n'; |
1962 | buf[2] = 0x00; |
1963 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); |
1964 | } |
1965 | |
1966 | static ssize_t write_enabled_file_bool(struct file *file, |
1967 | const char __user *user_buf, size_t count, loff_t *ppos) |
1968 | { |
1969 | char buf[32]; |
1970 | int buf_size; |
1971 | |
1972 | buf_size = min(count, (sizeof(buf)-1)); |
1973 | if (copy_from_user(buf, user_buf, buf_size)) |
1974 | return -EFAULT; |
1975 | |
1976 | switch (buf[0]) { |
1977 | case 'y': |
1978 | case 'Y': |
1979 | case '1': |
1980 | arm_all_kprobes(); |
1981 | break; |
1982 | case 'n': |
1983 | case 'N': |
1984 | case '0': |
1985 | disarm_all_kprobes(); |
1986 | break; |
1987 | } |
1988 | |
1989 | return count; |
1990 | } |
1991 | |
1992 | static const struct file_operations fops_kp = { |
1993 | .read = read_enabled_file_bool, |
1994 | .write = write_enabled_file_bool, |
1995 | }; |
1996 | |
1997 | static int __kprobes debugfs_kprobe_init(void) |
1998 | { |
1999 | struct dentry *dir, *file; |
2000 | unsigned int value = 1; |
2001 | |
2002 | dir = debugfs_create_dir("kprobes", NULL); |
2003 | if (!dir) |
2004 | return -ENOMEM; |
2005 | |
2006 | file = debugfs_create_file("list", 0444, dir, NULL, |
2007 | &debugfs_kprobes_operations); |
2008 | if (!file) { |
2009 | debugfs_remove(dir); |
2010 | return -ENOMEM; |
2011 | } |
2012 | |
2013 | file = debugfs_create_file("enabled", 0600, dir, |
2014 | &value, &fops_kp); |
2015 | if (!file) { |
2016 | debugfs_remove(dir); |
2017 | return -ENOMEM; |
2018 | } |
2019 | |
2020 | return 0; |
2021 | } |
2022 | |
2023 | late_initcall(debugfs_kprobe_init); |
2024 | #endif /* CONFIG_DEBUG_FS */ |
2025 | |
2026 | module_init(init_kprobes); |
2027 | |
2028 | /* defined in arch/.../kernel/kprobes.c */ |
2029 | EXPORT_SYMBOL_GPL(jprobe_return); |
2030 |
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