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Source at commit fbf123cd4cc0c097fe9a99c90109ebb2a5e94a50 created 10 years 3 months ago. By Lars-Peter Clausen, dma: jz4740: Dequeue descriptor from active list before completing it | |
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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/export.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 | #include <linux/jump_label.h> |
51 | |
52 | #include <asm-generic/sections.h> |
53 | #include <asm/cacheflush.h> |
54 | #include <asm/errno.h> |
55 | #include <asm/uaccess.h> |
56 | |
57 | #define KPROBE_HASH_BITS 6 |
58 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
59 | |
60 | |
61 | /* |
62 | * Some oddball architectures like 64bit powerpc have function descriptors |
63 | * so this must be overridable. |
64 | */ |
65 | #ifndef kprobe_lookup_name |
66 | #define kprobe_lookup_name(name, addr) \ |
67 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) |
68 | #endif |
69 | |
70 | static int kprobes_initialized; |
71 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
72 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
73 | |
74 | /* NOTE: change this value only with kprobe_mutex held */ |
75 | static bool kprobes_all_disarmed; |
76 | |
77 | /* This protects kprobe_table and optimizing_list */ |
78 | static DEFINE_MUTEX(kprobe_mutex); |
79 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
80 | static struct { |
81 | raw_spinlock_t lock ____cacheline_aligned_in_smp; |
82 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
83 | |
84 | static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
85 | { |
86 | return &(kretprobe_table_locks[hash].lock); |
87 | } |
88 | |
89 | /* Blacklist -- list of struct kprobe_blacklist_entry */ |
90 | static LIST_HEAD(kprobe_blacklist); |
91 | |
92 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
93 | /* |
94 | * kprobe->ainsn.insn points to the copy of the instruction to be |
95 | * single-stepped. x86_64, POWER4 and above have no-exec support and |
96 | * stepping on the instruction on a vmalloced/kmalloced/data page |
97 | * is a recipe for disaster |
98 | */ |
99 | struct kprobe_insn_page { |
100 | struct list_head list; |
101 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
102 | struct kprobe_insn_cache *cache; |
103 | int nused; |
104 | int ngarbage; |
105 | char slot_used[]; |
106 | }; |
107 | |
108 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
109 | (offsetof(struct kprobe_insn_page, slot_used) + \ |
110 | (sizeof(char) * (slots))) |
111 | |
112 | static int slots_per_page(struct kprobe_insn_cache *c) |
113 | { |
114 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); |
115 | } |
116 | |
117 | enum kprobe_slot_state { |
118 | SLOT_CLEAN = 0, |
119 | SLOT_DIRTY = 1, |
120 | SLOT_USED = 2, |
121 | }; |
122 | |
123 | static void *alloc_insn_page(void) |
124 | { |
125 | return module_alloc(PAGE_SIZE); |
126 | } |
127 | |
128 | static void free_insn_page(void *page) |
129 | { |
130 | module_free(NULL, page); |
131 | } |
132 | |
133 | struct kprobe_insn_cache kprobe_insn_slots = { |
134 | .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), |
135 | .alloc = alloc_insn_page, |
136 | .free = free_insn_page, |
137 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
138 | .insn_size = MAX_INSN_SIZE, |
139 | .nr_garbage = 0, |
140 | }; |
141 | static int collect_garbage_slots(struct kprobe_insn_cache *c); |
142 | |
143 | /** |
144 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
145 | * We allocate an executable page if there's no room on existing ones. |
146 | */ |
147 | kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
148 | { |
149 | struct kprobe_insn_page *kip; |
150 | kprobe_opcode_t *slot = NULL; |
151 | |
152 | mutex_lock(&c->mutex); |
153 | retry: |
154 | list_for_each_entry(kip, &c->pages, list) { |
155 | if (kip->nused < slots_per_page(c)) { |
156 | int i; |
157 | for (i = 0; i < slots_per_page(c); i++) { |
158 | if (kip->slot_used[i] == SLOT_CLEAN) { |
159 | kip->slot_used[i] = SLOT_USED; |
160 | kip->nused++; |
161 | slot = kip->insns + (i * c->insn_size); |
162 | goto out; |
163 | } |
164 | } |
165 | /* kip->nused is broken. Fix it. */ |
166 | kip->nused = slots_per_page(c); |
167 | WARN_ON(1); |
168 | } |
169 | } |
170 | |
171 | /* If there are any garbage slots, collect it and try again. */ |
172 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
173 | goto retry; |
174 | |
175 | /* All out of space. Need to allocate a new page. */ |
176 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); |
177 | if (!kip) |
178 | goto out; |
179 | |
180 | /* |
181 | * Use module_alloc so this page is within +/- 2GB of where the |
182 | * kernel image and loaded module images reside. This is required |
183 | * so x86_64 can correctly handle the %rip-relative fixups. |
184 | */ |
185 | kip->insns = c->alloc(); |
186 | if (!kip->insns) { |
187 | kfree(kip); |
188 | goto out; |
189 | } |
190 | INIT_LIST_HEAD(&kip->list); |
191 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
192 | kip->slot_used[0] = SLOT_USED; |
193 | kip->nused = 1; |
194 | kip->ngarbage = 0; |
195 | kip->cache = c; |
196 | list_add(&kip->list, &c->pages); |
197 | slot = kip->insns; |
198 | out: |
199 | mutex_unlock(&c->mutex); |
200 | return slot; |
201 | } |
202 | |
203 | /* Return 1 if all garbages are collected, otherwise 0. */ |
204 | static int collect_one_slot(struct kprobe_insn_page *kip, int idx) |
205 | { |
206 | kip->slot_used[idx] = SLOT_CLEAN; |
207 | kip->nused--; |
208 | if (kip->nused == 0) { |
209 | /* |
210 | * Page is no longer in use. Free it unless |
211 | * it's the last one. We keep the last one |
212 | * so as not to have to set it up again the |
213 | * next time somebody inserts a probe. |
214 | */ |
215 | if (!list_is_singular(&kip->list)) { |
216 | list_del(&kip->list); |
217 | kip->cache->free(kip->insns); |
218 | kfree(kip); |
219 | } |
220 | return 1; |
221 | } |
222 | return 0; |
223 | } |
224 | |
225 | static int collect_garbage_slots(struct kprobe_insn_cache *c) |
226 | { |
227 | struct kprobe_insn_page *kip, *next; |
228 | |
229 | /* Ensure no-one is interrupted on the garbages */ |
230 | synchronize_sched(); |
231 | |
232 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
233 | int i; |
234 | if (kip->ngarbage == 0) |
235 | continue; |
236 | kip->ngarbage = 0; /* we will collect all garbages */ |
237 | for (i = 0; i < slots_per_page(c); i++) { |
238 | if (kip->slot_used[i] == SLOT_DIRTY && |
239 | collect_one_slot(kip, i)) |
240 | break; |
241 | } |
242 | } |
243 | c->nr_garbage = 0; |
244 | return 0; |
245 | } |
246 | |
247 | void __free_insn_slot(struct kprobe_insn_cache *c, |
248 | kprobe_opcode_t *slot, int dirty) |
249 | { |
250 | struct kprobe_insn_page *kip; |
251 | |
252 | mutex_lock(&c->mutex); |
253 | list_for_each_entry(kip, &c->pages, list) { |
254 | long idx = ((long)slot - (long)kip->insns) / |
255 | (c->insn_size * sizeof(kprobe_opcode_t)); |
256 | if (idx >= 0 && idx < slots_per_page(c)) { |
257 | WARN_ON(kip->slot_used[idx] != SLOT_USED); |
258 | if (dirty) { |
259 | kip->slot_used[idx] = SLOT_DIRTY; |
260 | kip->ngarbage++; |
261 | if (++c->nr_garbage > slots_per_page(c)) |
262 | collect_garbage_slots(c); |
263 | } else |
264 | collect_one_slot(kip, idx); |
265 | goto out; |
266 | } |
267 | } |
268 | /* Could not free this slot. */ |
269 | WARN_ON(1); |
270 | out: |
271 | mutex_unlock(&c->mutex); |
272 | } |
273 | |
274 | #ifdef CONFIG_OPTPROBES |
275 | /* For optimized_kprobe buffer */ |
276 | struct kprobe_insn_cache kprobe_optinsn_slots = { |
277 | .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), |
278 | .alloc = alloc_insn_page, |
279 | .free = free_insn_page, |
280 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
281 | /* .insn_size is initialized later */ |
282 | .nr_garbage = 0, |
283 | }; |
284 | #endif |
285 | #endif |
286 | |
287 | /* We have preemption disabled.. so it is safe to use __ versions */ |
288 | static inline void set_kprobe_instance(struct kprobe *kp) |
289 | { |
290 | __this_cpu_write(kprobe_instance, kp); |
291 | } |
292 | |
293 | static inline void reset_kprobe_instance(void) |
294 | { |
295 | __this_cpu_write(kprobe_instance, NULL); |
296 | } |
297 | |
298 | /* |
299 | * This routine is called either: |
300 | * - under the kprobe_mutex - during kprobe_[un]register() |
301 | * OR |
302 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
303 | */ |
304 | struct kprobe *get_kprobe(void *addr) |
305 | { |
306 | struct hlist_head *head; |
307 | struct kprobe *p; |
308 | |
309 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
310 | hlist_for_each_entry_rcu(p, head, hlist) { |
311 | if (p->addr == addr) |
312 | return p; |
313 | } |
314 | |
315 | return NULL; |
316 | } |
317 | NOKPROBE_SYMBOL(get_kprobe); |
318 | |
319 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
320 | |
321 | /* Return true if the kprobe is an aggregator */ |
322 | static inline int kprobe_aggrprobe(struct kprobe *p) |
323 | { |
324 | return p->pre_handler == aggr_pre_handler; |
325 | } |
326 | |
327 | /* Return true(!0) if the kprobe is unused */ |
328 | static inline int kprobe_unused(struct kprobe *p) |
329 | { |
330 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && |
331 | list_empty(&p->list); |
332 | } |
333 | |
334 | /* |
335 | * Keep all fields in the kprobe consistent |
336 | */ |
337 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
338 | { |
339 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
340 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); |
341 | } |
342 | |
343 | #ifdef CONFIG_OPTPROBES |
344 | /* NOTE: change this value only with kprobe_mutex held */ |
345 | static bool kprobes_allow_optimization; |
346 | |
347 | /* |
348 | * Call all pre_handler on the list, but ignores its return value. |
349 | * This must be called from arch-dep optimized caller. |
350 | */ |
351 | void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
352 | { |
353 | struct kprobe *kp; |
354 | |
355 | list_for_each_entry_rcu(kp, &p->list, list) { |
356 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
357 | set_kprobe_instance(kp); |
358 | kp->pre_handler(kp, regs); |
359 | } |
360 | reset_kprobe_instance(); |
361 | } |
362 | } |
363 | NOKPROBE_SYMBOL(opt_pre_handler); |
364 | |
365 | /* Free optimized instructions and optimized_kprobe */ |
366 | static void free_aggr_kprobe(struct kprobe *p) |
367 | { |
368 | struct optimized_kprobe *op; |
369 | |
370 | op = container_of(p, struct optimized_kprobe, kp); |
371 | arch_remove_optimized_kprobe(op); |
372 | arch_remove_kprobe(p); |
373 | kfree(op); |
374 | } |
375 | |
376 | /* Return true(!0) if the kprobe is ready for optimization. */ |
377 | static inline int kprobe_optready(struct kprobe *p) |
378 | { |
379 | struct optimized_kprobe *op; |
380 | |
381 | if (kprobe_aggrprobe(p)) { |
382 | op = container_of(p, struct optimized_kprobe, kp); |
383 | return arch_prepared_optinsn(&op->optinsn); |
384 | } |
385 | |
386 | return 0; |
387 | } |
388 | |
389 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
390 | static inline int kprobe_disarmed(struct kprobe *p) |
391 | { |
392 | struct optimized_kprobe *op; |
393 | |
394 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ |
395 | if (!kprobe_aggrprobe(p)) |
396 | return kprobe_disabled(p); |
397 | |
398 | op = container_of(p, struct optimized_kprobe, kp); |
399 | |
400 | return kprobe_disabled(p) && list_empty(&op->list); |
401 | } |
402 | |
403 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ |
404 | static int kprobe_queued(struct kprobe *p) |
405 | { |
406 | struct optimized_kprobe *op; |
407 | |
408 | if (kprobe_aggrprobe(p)) { |
409 | op = container_of(p, struct optimized_kprobe, kp); |
410 | if (!list_empty(&op->list)) |
411 | return 1; |
412 | } |
413 | return 0; |
414 | } |
415 | |
416 | /* |
417 | * Return an optimized kprobe whose optimizing code replaces |
418 | * instructions including addr (exclude breakpoint). |
419 | */ |
420 | static struct kprobe *get_optimized_kprobe(unsigned long addr) |
421 | { |
422 | int i; |
423 | struct kprobe *p = NULL; |
424 | struct optimized_kprobe *op; |
425 | |
426 | /* Don't check i == 0, since that is a breakpoint case. */ |
427 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) |
428 | p = get_kprobe((void *)(addr - i)); |
429 | |
430 | if (p && kprobe_optready(p)) { |
431 | op = container_of(p, struct optimized_kprobe, kp); |
432 | if (arch_within_optimized_kprobe(op, addr)) |
433 | return p; |
434 | } |
435 | |
436 | return NULL; |
437 | } |
438 | |
439 | /* Optimization staging list, protected by kprobe_mutex */ |
440 | static LIST_HEAD(optimizing_list); |
441 | static LIST_HEAD(unoptimizing_list); |
442 | static LIST_HEAD(freeing_list); |
443 | |
444 | static void kprobe_optimizer(struct work_struct *work); |
445 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); |
446 | #define OPTIMIZE_DELAY 5 |
447 | |
448 | /* |
449 | * Optimize (replace a breakpoint with a jump) kprobes listed on |
450 | * optimizing_list. |
451 | */ |
452 | static void do_optimize_kprobes(void) |
453 | { |
454 | /* Optimization never be done when disarmed */ |
455 | if (kprobes_all_disarmed || !kprobes_allow_optimization || |
456 | list_empty(&optimizing_list)) |
457 | return; |
458 | |
459 | /* |
460 | * The optimization/unoptimization refers online_cpus via |
461 | * stop_machine() and cpu-hotplug modifies online_cpus. |
462 | * And same time, text_mutex will be held in cpu-hotplug and here. |
463 | * This combination can cause a deadlock (cpu-hotplug try to lock |
464 | * text_mutex but stop_machine can not be done because online_cpus |
465 | * has been changed) |
466 | * To avoid this deadlock, we need to call get_online_cpus() |
467 | * for preventing cpu-hotplug outside of text_mutex locking. |
468 | */ |
469 | get_online_cpus(); |
470 | mutex_lock(&text_mutex); |
471 | arch_optimize_kprobes(&optimizing_list); |
472 | mutex_unlock(&text_mutex); |
473 | put_online_cpus(); |
474 | } |
475 | |
476 | /* |
477 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint |
478 | * if need) kprobes listed on unoptimizing_list. |
479 | */ |
480 | static void do_unoptimize_kprobes(void) |
481 | { |
482 | struct optimized_kprobe *op, *tmp; |
483 | |
484 | /* Unoptimization must be done anytime */ |
485 | if (list_empty(&unoptimizing_list)) |
486 | return; |
487 | |
488 | /* Ditto to do_optimize_kprobes */ |
489 | get_online_cpus(); |
490 | mutex_lock(&text_mutex); |
491 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
492 | /* Loop free_list for disarming */ |
493 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
494 | /* Disarm probes if marked disabled */ |
495 | if (kprobe_disabled(&op->kp)) |
496 | arch_disarm_kprobe(&op->kp); |
497 | if (kprobe_unused(&op->kp)) { |
498 | /* |
499 | * Remove unused probes from hash list. After waiting |
500 | * for synchronization, these probes are reclaimed. |
501 | * (reclaiming is done by do_free_cleaned_kprobes.) |
502 | */ |
503 | hlist_del_rcu(&op->kp.hlist); |
504 | } else |
505 | list_del_init(&op->list); |
506 | } |
507 | mutex_unlock(&text_mutex); |
508 | put_online_cpus(); |
509 | } |
510 | |
511 | /* Reclaim all kprobes on the free_list */ |
512 | static void do_free_cleaned_kprobes(void) |
513 | { |
514 | struct optimized_kprobe *op, *tmp; |
515 | |
516 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
517 | BUG_ON(!kprobe_unused(&op->kp)); |
518 | list_del_init(&op->list); |
519 | free_aggr_kprobe(&op->kp); |
520 | } |
521 | } |
522 | |
523 | /* Start optimizer after OPTIMIZE_DELAY passed */ |
524 | static void kick_kprobe_optimizer(void) |
525 | { |
526 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
527 | } |
528 | |
529 | /* Kprobe jump optimizer */ |
530 | static void kprobe_optimizer(struct work_struct *work) |
531 | { |
532 | mutex_lock(&kprobe_mutex); |
533 | /* Lock modules while optimizing kprobes */ |
534 | mutex_lock(&module_mutex); |
535 | |
536 | /* |
537 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
538 | * kprobes before waiting for quiesence period. |
539 | */ |
540 | do_unoptimize_kprobes(); |
541 | |
542 | /* |
543 | * Step 2: Wait for quiesence period to ensure all running interrupts |
544 | * are done. Because optprobe may modify multiple instructions |
545 | * there is a chance that Nth instruction is interrupted. In that |
546 | * case, running interrupt can return to 2nd-Nth byte of jump |
547 | * instruction. This wait is for avoiding it. |
548 | */ |
549 | synchronize_sched(); |
550 | |
551 | /* Step 3: Optimize kprobes after quiesence period */ |
552 | do_optimize_kprobes(); |
553 | |
554 | /* Step 4: Free cleaned kprobes after quiesence period */ |
555 | do_free_cleaned_kprobes(); |
556 | |
557 | mutex_unlock(&module_mutex); |
558 | mutex_unlock(&kprobe_mutex); |
559 | |
560 | /* Step 5: Kick optimizer again if needed */ |
561 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
562 | kick_kprobe_optimizer(); |
563 | } |
564 | |
565 | /* Wait for completing optimization and unoptimization */ |
566 | static void wait_for_kprobe_optimizer(void) |
567 | { |
568 | mutex_lock(&kprobe_mutex); |
569 | |
570 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { |
571 | mutex_unlock(&kprobe_mutex); |
572 | |
573 | /* this will also make optimizing_work execute immmediately */ |
574 | flush_delayed_work(&optimizing_work); |
575 | /* @optimizing_work might not have been queued yet, relax */ |
576 | cpu_relax(); |
577 | |
578 | mutex_lock(&kprobe_mutex); |
579 | } |
580 | |
581 | mutex_unlock(&kprobe_mutex); |
582 | } |
583 | |
584 | /* Optimize kprobe if p is ready to be optimized */ |
585 | static void optimize_kprobe(struct kprobe *p) |
586 | { |
587 | struct optimized_kprobe *op; |
588 | |
589 | /* Check if the kprobe is disabled or not ready for optimization. */ |
590 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
591 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
592 | return; |
593 | |
594 | /* Both of break_handler and post_handler are not supported. */ |
595 | if (p->break_handler || p->post_handler) |
596 | return; |
597 | |
598 | op = container_of(p, struct optimized_kprobe, kp); |
599 | |
600 | /* Check there is no other kprobes at the optimized instructions */ |
601 | if (arch_check_optimized_kprobe(op) < 0) |
602 | return; |
603 | |
604 | /* Check if it is already optimized. */ |
605 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) |
606 | return; |
607 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
608 | |
609 | if (!list_empty(&op->list)) |
610 | /* This is under unoptimizing. Just dequeue the probe */ |
611 | list_del_init(&op->list); |
612 | else { |
613 | list_add(&op->list, &optimizing_list); |
614 | kick_kprobe_optimizer(); |
615 | } |
616 | } |
617 | |
618 | /* Short cut to direct unoptimizing */ |
619 | static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
620 | { |
621 | get_online_cpus(); |
622 | arch_unoptimize_kprobe(op); |
623 | put_online_cpus(); |
624 | if (kprobe_disabled(&op->kp)) |
625 | arch_disarm_kprobe(&op->kp); |
626 | } |
627 | |
628 | /* Unoptimize a kprobe if p is optimized */ |
629 | static void unoptimize_kprobe(struct kprobe *p, bool force) |
630 | { |
631 | struct optimized_kprobe *op; |
632 | |
633 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
634 | return; /* This is not an optprobe nor optimized */ |
635 | |
636 | op = container_of(p, struct optimized_kprobe, kp); |
637 | if (!kprobe_optimized(p)) { |
638 | /* Unoptimized or unoptimizing case */ |
639 | if (force && !list_empty(&op->list)) { |
640 | /* |
641 | * Only if this is unoptimizing kprobe and forced, |
642 | * forcibly unoptimize it. (No need to unoptimize |
643 | * unoptimized kprobe again :) |
644 | */ |
645 | list_del_init(&op->list); |
646 | force_unoptimize_kprobe(op); |
647 | } |
648 | return; |
649 | } |
650 | |
651 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
652 | if (!list_empty(&op->list)) { |
653 | /* Dequeue from the optimization queue */ |
654 | list_del_init(&op->list); |
655 | return; |
656 | } |
657 | /* Optimized kprobe case */ |
658 | if (force) |
659 | /* Forcibly update the code: this is a special case */ |
660 | force_unoptimize_kprobe(op); |
661 | else { |
662 | list_add(&op->list, &unoptimizing_list); |
663 | kick_kprobe_optimizer(); |
664 | } |
665 | } |
666 | |
667 | /* Cancel unoptimizing for reusing */ |
668 | static void reuse_unused_kprobe(struct kprobe *ap) |
669 | { |
670 | struct optimized_kprobe *op; |
671 | |
672 | BUG_ON(!kprobe_unused(ap)); |
673 | /* |
674 | * Unused kprobe MUST be on the way of delayed unoptimizing (means |
675 | * there is still a relative jump) and disabled. |
676 | */ |
677 | op = container_of(ap, struct optimized_kprobe, kp); |
678 | if (unlikely(list_empty(&op->list))) |
679 | printk(KERN_WARNING "Warning: found a stray unused " |
680 | "aggrprobe@%p\n", ap->addr); |
681 | /* Enable the probe again */ |
682 | ap->flags &= ~KPROBE_FLAG_DISABLED; |
683 | /* Optimize it again (remove from op->list) */ |
684 | BUG_ON(!kprobe_optready(ap)); |
685 | optimize_kprobe(ap); |
686 | } |
687 | |
688 | /* Remove optimized instructions */ |
689 | static void kill_optimized_kprobe(struct kprobe *p) |
690 | { |
691 | struct optimized_kprobe *op; |
692 | |
693 | op = container_of(p, struct optimized_kprobe, kp); |
694 | if (!list_empty(&op->list)) |
695 | /* Dequeue from the (un)optimization queue */ |
696 | list_del_init(&op->list); |
697 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
698 | |
699 | if (kprobe_unused(p)) { |
700 | /* Enqueue if it is unused */ |
701 | list_add(&op->list, &freeing_list); |
702 | /* |
703 | * Remove unused probes from the hash list. After waiting |
704 | * for synchronization, this probe is reclaimed. |
705 | * (reclaiming is done by do_free_cleaned_kprobes().) |
706 | */ |
707 | hlist_del_rcu(&op->kp.hlist); |
708 | } |
709 | |
710 | /* Don't touch the code, because it is already freed. */ |
711 | arch_remove_optimized_kprobe(op); |
712 | } |
713 | |
714 | /* Try to prepare optimized instructions */ |
715 | static void prepare_optimized_kprobe(struct kprobe *p) |
716 | { |
717 | struct optimized_kprobe *op; |
718 | |
719 | op = container_of(p, struct optimized_kprobe, kp); |
720 | arch_prepare_optimized_kprobe(op); |
721 | } |
722 | |
723 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
724 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
725 | { |
726 | struct optimized_kprobe *op; |
727 | |
728 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); |
729 | if (!op) |
730 | return NULL; |
731 | |
732 | INIT_LIST_HEAD(&op->list); |
733 | op->kp.addr = p->addr; |
734 | arch_prepare_optimized_kprobe(op); |
735 | |
736 | return &op->kp; |
737 | } |
738 | |
739 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
740 | |
741 | /* |
742 | * Prepare an optimized_kprobe and optimize it |
743 | * NOTE: p must be a normal registered kprobe |
744 | */ |
745 | static void try_to_optimize_kprobe(struct kprobe *p) |
746 | { |
747 | struct kprobe *ap; |
748 | struct optimized_kprobe *op; |
749 | |
750 | /* Impossible to optimize ftrace-based kprobe */ |
751 | if (kprobe_ftrace(p)) |
752 | return; |
753 | |
754 | /* For preparing optimization, jump_label_text_reserved() is called */ |
755 | jump_label_lock(); |
756 | mutex_lock(&text_mutex); |
757 | |
758 | ap = alloc_aggr_kprobe(p); |
759 | if (!ap) |
760 | goto out; |
761 | |
762 | op = container_of(ap, struct optimized_kprobe, kp); |
763 | if (!arch_prepared_optinsn(&op->optinsn)) { |
764 | /* If failed to setup optimizing, fallback to kprobe */ |
765 | arch_remove_optimized_kprobe(op); |
766 | kfree(op); |
767 | goto out; |
768 | } |
769 | |
770 | init_aggr_kprobe(ap, p); |
771 | optimize_kprobe(ap); /* This just kicks optimizer thread */ |
772 | |
773 | out: |
774 | mutex_unlock(&text_mutex); |
775 | jump_label_unlock(); |
776 | } |
777 | |
778 | #ifdef CONFIG_SYSCTL |
779 | static void optimize_all_kprobes(void) |
780 | { |
781 | struct hlist_head *head; |
782 | struct kprobe *p; |
783 | unsigned int i; |
784 | |
785 | mutex_lock(&kprobe_mutex); |
786 | /* If optimization is already allowed, just return */ |
787 | if (kprobes_allow_optimization) |
788 | goto out; |
789 | |
790 | kprobes_allow_optimization = true; |
791 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
792 | head = &kprobe_table[i]; |
793 | hlist_for_each_entry_rcu(p, head, hlist) |
794 | if (!kprobe_disabled(p)) |
795 | optimize_kprobe(p); |
796 | } |
797 | printk(KERN_INFO "Kprobes globally optimized\n"); |
798 | out: |
799 | mutex_unlock(&kprobe_mutex); |
800 | } |
801 | |
802 | static void unoptimize_all_kprobes(void) |
803 | { |
804 | struct hlist_head *head; |
805 | struct kprobe *p; |
806 | unsigned int i; |
807 | |
808 | mutex_lock(&kprobe_mutex); |
809 | /* If optimization is already prohibited, just return */ |
810 | if (!kprobes_allow_optimization) { |
811 | mutex_unlock(&kprobe_mutex); |
812 | return; |
813 | } |
814 | |
815 | kprobes_allow_optimization = false; |
816 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
817 | head = &kprobe_table[i]; |
818 | hlist_for_each_entry_rcu(p, head, hlist) { |
819 | if (!kprobe_disabled(p)) |
820 | unoptimize_kprobe(p, false); |
821 | } |
822 | } |
823 | mutex_unlock(&kprobe_mutex); |
824 | |
825 | /* Wait for unoptimizing completion */ |
826 | wait_for_kprobe_optimizer(); |
827 | printk(KERN_INFO "Kprobes globally unoptimized\n"); |
828 | } |
829 | |
830 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
831 | int sysctl_kprobes_optimization; |
832 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, |
833 | void __user *buffer, size_t *length, |
834 | loff_t *ppos) |
835 | { |
836 | int ret; |
837 | |
838 | mutex_lock(&kprobe_sysctl_mutex); |
839 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
840 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); |
841 | |
842 | if (sysctl_kprobes_optimization) |
843 | optimize_all_kprobes(); |
844 | else |
845 | unoptimize_all_kprobes(); |
846 | mutex_unlock(&kprobe_sysctl_mutex); |
847 | |
848 | return ret; |
849 | } |
850 | #endif /* CONFIG_SYSCTL */ |
851 | |
852 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
853 | static void __arm_kprobe(struct kprobe *p) |
854 | { |
855 | struct kprobe *_p; |
856 | |
857 | /* Check collision with other optimized kprobes */ |
858 | _p = get_optimized_kprobe((unsigned long)p->addr); |
859 | if (unlikely(_p)) |
860 | /* Fallback to unoptimized kprobe */ |
861 | unoptimize_kprobe(_p, true); |
862 | |
863 | arch_arm_kprobe(p); |
864 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ |
865 | } |
866 | |
867 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
868 | static void __disarm_kprobe(struct kprobe *p, bool reopt) |
869 | { |
870 | struct kprobe *_p; |
871 | |
872 | unoptimize_kprobe(p, false); /* Try to unoptimize */ |
873 | |
874 | if (!kprobe_queued(p)) { |
875 | arch_disarm_kprobe(p); |
876 | /* If another kprobe was blocked, optimize it. */ |
877 | _p = get_optimized_kprobe((unsigned long)p->addr); |
878 | if (unlikely(_p) && reopt) |
879 | optimize_kprobe(_p); |
880 | } |
881 | /* TODO: reoptimize others after unoptimized this probe */ |
882 | } |
883 | |
884 | #else /* !CONFIG_OPTPROBES */ |
885 | |
886 | #define optimize_kprobe(p) do {} while (0) |
887 | #define unoptimize_kprobe(p, f) do {} while (0) |
888 | #define kill_optimized_kprobe(p) do {} while (0) |
889 | #define prepare_optimized_kprobe(p) do {} while (0) |
890 | #define try_to_optimize_kprobe(p) do {} while (0) |
891 | #define __arm_kprobe(p) arch_arm_kprobe(p) |
892 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
893 | #define kprobe_disarmed(p) kprobe_disabled(p) |
894 | #define wait_for_kprobe_optimizer() do {} while (0) |
895 | |
896 | /* There should be no unused kprobes can be reused without optimization */ |
897 | static void reuse_unused_kprobe(struct kprobe *ap) |
898 | { |
899 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); |
900 | BUG_ON(kprobe_unused(ap)); |
901 | } |
902 | |
903 | static void free_aggr_kprobe(struct kprobe *p) |
904 | { |
905 | arch_remove_kprobe(p); |
906 | kfree(p); |
907 | } |
908 | |
909 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
910 | { |
911 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
912 | } |
913 | #endif /* CONFIG_OPTPROBES */ |
914 | |
915 | #ifdef CONFIG_KPROBES_ON_FTRACE |
916 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
917 | .func = kprobe_ftrace_handler, |
918 | .flags = FTRACE_OPS_FL_SAVE_REGS, |
919 | }; |
920 | static int kprobe_ftrace_enabled; |
921 | |
922 | /* Must ensure p->addr is really on ftrace */ |
923 | static int prepare_kprobe(struct kprobe *p) |
924 | { |
925 | if (!kprobe_ftrace(p)) |
926 | return arch_prepare_kprobe(p); |
927 | |
928 | return arch_prepare_kprobe_ftrace(p); |
929 | } |
930 | |
931 | /* Caller must lock kprobe_mutex */ |
932 | static void arm_kprobe_ftrace(struct kprobe *p) |
933 | { |
934 | int ret; |
935 | |
936 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, |
937 | (unsigned long)p->addr, 0, 0); |
938 | WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret); |
939 | kprobe_ftrace_enabled++; |
940 | if (kprobe_ftrace_enabled == 1) { |
941 | ret = register_ftrace_function(&kprobe_ftrace_ops); |
942 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); |
943 | } |
944 | } |
945 | |
946 | /* Caller must lock kprobe_mutex */ |
947 | static void disarm_kprobe_ftrace(struct kprobe *p) |
948 | { |
949 | int ret; |
950 | |
951 | kprobe_ftrace_enabled--; |
952 | if (kprobe_ftrace_enabled == 0) { |
953 | ret = unregister_ftrace_function(&kprobe_ftrace_ops); |
954 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); |
955 | } |
956 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, |
957 | (unsigned long)p->addr, 1, 0); |
958 | WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret); |
959 | } |
960 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
961 | #define prepare_kprobe(p) arch_prepare_kprobe(p) |
962 | #define arm_kprobe_ftrace(p) do {} while (0) |
963 | #define disarm_kprobe_ftrace(p) do {} while (0) |
964 | #endif |
965 | |
966 | /* Arm a kprobe with text_mutex */ |
967 | static void arm_kprobe(struct kprobe *kp) |
968 | { |
969 | if (unlikely(kprobe_ftrace(kp))) { |
970 | arm_kprobe_ftrace(kp); |
971 | return; |
972 | } |
973 | /* |
974 | * Here, since __arm_kprobe() doesn't use stop_machine(), |
975 | * this doesn't cause deadlock on text_mutex. So, we don't |
976 | * need get_online_cpus(). |
977 | */ |
978 | mutex_lock(&text_mutex); |
979 | __arm_kprobe(kp); |
980 | mutex_unlock(&text_mutex); |
981 | } |
982 | |
983 | /* Disarm a kprobe with text_mutex */ |
984 | static void disarm_kprobe(struct kprobe *kp, bool reopt) |
985 | { |
986 | if (unlikely(kprobe_ftrace(kp))) { |
987 | disarm_kprobe_ftrace(kp); |
988 | return; |
989 | } |
990 | /* Ditto */ |
991 | mutex_lock(&text_mutex); |
992 | __disarm_kprobe(kp, reopt); |
993 | mutex_unlock(&text_mutex); |
994 | } |
995 | |
996 | /* |
997 | * Aggregate handlers for multiple kprobes support - these handlers |
998 | * take care of invoking the individual kprobe handlers on p->list |
999 | */ |
1000 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
1001 | { |
1002 | struct kprobe *kp; |
1003 | |
1004 | list_for_each_entry_rcu(kp, &p->list, list) { |
1005 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
1006 | set_kprobe_instance(kp); |
1007 | if (kp->pre_handler(kp, regs)) |
1008 | return 1; |
1009 | } |
1010 | reset_kprobe_instance(); |
1011 | } |
1012 | return 0; |
1013 | } |
1014 | NOKPROBE_SYMBOL(aggr_pre_handler); |
1015 | |
1016 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1017 | unsigned long flags) |
1018 | { |
1019 | struct kprobe *kp; |
1020 | |
1021 | list_for_each_entry_rcu(kp, &p->list, list) { |
1022 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
1023 | set_kprobe_instance(kp); |
1024 | kp->post_handler(kp, regs, flags); |
1025 | reset_kprobe_instance(); |
1026 | } |
1027 | } |
1028 | } |
1029 | NOKPROBE_SYMBOL(aggr_post_handler); |
1030 | |
1031 | static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
1032 | int trapnr) |
1033 | { |
1034 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
1035 | |
1036 | /* |
1037 | * if we faulted "during" the execution of a user specified |
1038 | * probe handler, invoke just that probe's fault handler |
1039 | */ |
1040 | if (cur && cur->fault_handler) { |
1041 | if (cur->fault_handler(cur, regs, trapnr)) |
1042 | return 1; |
1043 | } |
1044 | return 0; |
1045 | } |
1046 | NOKPROBE_SYMBOL(aggr_fault_handler); |
1047 | |
1048 | static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
1049 | { |
1050 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
1051 | int ret = 0; |
1052 | |
1053 | if (cur && cur->break_handler) { |
1054 | if (cur->break_handler(cur, regs)) |
1055 | ret = 1; |
1056 | } |
1057 | reset_kprobe_instance(); |
1058 | return ret; |
1059 | } |
1060 | NOKPROBE_SYMBOL(aggr_break_handler); |
1061 | |
1062 | /* Walks the list and increments nmissed count for multiprobe case */ |
1063 | void kprobes_inc_nmissed_count(struct kprobe *p) |
1064 | { |
1065 | struct kprobe *kp; |
1066 | if (!kprobe_aggrprobe(p)) { |
1067 | p->nmissed++; |
1068 | } else { |
1069 | list_for_each_entry_rcu(kp, &p->list, list) |
1070 | kp->nmissed++; |
1071 | } |
1072 | return; |
1073 | } |
1074 | NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
1075 | |
1076 | void recycle_rp_inst(struct kretprobe_instance *ri, |
1077 | struct hlist_head *head) |
1078 | { |
1079 | struct kretprobe *rp = ri->rp; |
1080 | |
1081 | /* remove rp inst off the rprobe_inst_table */ |
1082 | hlist_del(&ri->hlist); |
1083 | INIT_HLIST_NODE(&ri->hlist); |
1084 | if (likely(rp)) { |
1085 | raw_spin_lock(&rp->lock); |
1086 | hlist_add_head(&ri->hlist, &rp->free_instances); |
1087 | raw_spin_unlock(&rp->lock); |
1088 | } else |
1089 | /* Unregistering */ |
1090 | hlist_add_head(&ri->hlist, head); |
1091 | } |
1092 | NOKPROBE_SYMBOL(recycle_rp_inst); |
1093 | |
1094 | void kretprobe_hash_lock(struct task_struct *tsk, |
1095 | struct hlist_head **head, unsigned long *flags) |
1096 | __acquires(hlist_lock) |
1097 | { |
1098 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
1099 | raw_spinlock_t *hlist_lock; |
1100 | |
1101 | *head = &kretprobe_inst_table[hash]; |
1102 | hlist_lock = kretprobe_table_lock_ptr(hash); |
1103 | raw_spin_lock_irqsave(hlist_lock, *flags); |
1104 | } |
1105 | NOKPROBE_SYMBOL(kretprobe_hash_lock); |
1106 | |
1107 | static void kretprobe_table_lock(unsigned long hash, |
1108 | unsigned long *flags) |
1109 | __acquires(hlist_lock) |
1110 | { |
1111 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1112 | raw_spin_lock_irqsave(hlist_lock, *flags); |
1113 | } |
1114 | NOKPROBE_SYMBOL(kretprobe_table_lock); |
1115 | |
1116 | void kretprobe_hash_unlock(struct task_struct *tsk, |
1117 | unsigned long *flags) |
1118 | __releases(hlist_lock) |
1119 | { |
1120 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
1121 | raw_spinlock_t *hlist_lock; |
1122 | |
1123 | hlist_lock = kretprobe_table_lock_ptr(hash); |
1124 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
1125 | } |
1126 | NOKPROBE_SYMBOL(kretprobe_hash_unlock); |
1127 | |
1128 | static void kretprobe_table_unlock(unsigned long hash, |
1129 | unsigned long *flags) |
1130 | __releases(hlist_lock) |
1131 | { |
1132 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1133 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
1134 | } |
1135 | NOKPROBE_SYMBOL(kretprobe_table_unlock); |
1136 | |
1137 | /* |
1138 | * This function is called from finish_task_switch when task tk becomes dead, |
1139 | * so that we can recycle any function-return probe instances associated |
1140 | * with this task. These left over instances represent probed functions |
1141 | * that have been called but will never return. |
1142 | */ |
1143 | void kprobe_flush_task(struct task_struct *tk) |
1144 | { |
1145 | struct kretprobe_instance *ri; |
1146 | struct hlist_head *head, empty_rp; |
1147 | struct hlist_node *tmp; |
1148 | unsigned long hash, flags = 0; |
1149 | |
1150 | if (unlikely(!kprobes_initialized)) |
1151 | /* Early boot. kretprobe_table_locks not yet initialized. */ |
1152 | return; |
1153 | |
1154 | INIT_HLIST_HEAD(&empty_rp); |
1155 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1156 | head = &kretprobe_inst_table[hash]; |
1157 | kretprobe_table_lock(hash, &flags); |
1158 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
1159 | if (ri->task == tk) |
1160 | recycle_rp_inst(ri, &empty_rp); |
1161 | } |
1162 | kretprobe_table_unlock(hash, &flags); |
1163 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
1164 | hlist_del(&ri->hlist); |
1165 | kfree(ri); |
1166 | } |
1167 | } |
1168 | NOKPROBE_SYMBOL(kprobe_flush_task); |
1169 | |
1170 | static inline void free_rp_inst(struct kretprobe *rp) |
1171 | { |
1172 | struct kretprobe_instance *ri; |
1173 | struct hlist_node *next; |
1174 | |
1175 | hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) { |
1176 | hlist_del(&ri->hlist); |
1177 | kfree(ri); |
1178 | } |
1179 | } |
1180 | |
1181 | static void cleanup_rp_inst(struct kretprobe *rp) |
1182 | { |
1183 | unsigned long flags, hash; |
1184 | struct kretprobe_instance *ri; |
1185 | struct hlist_node *next; |
1186 | struct hlist_head *head; |
1187 | |
1188 | /* No race here */ |
1189 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1190 | kretprobe_table_lock(hash, &flags); |
1191 | head = &kretprobe_inst_table[hash]; |
1192 | hlist_for_each_entry_safe(ri, next, head, hlist) { |
1193 | if (ri->rp == rp) |
1194 | ri->rp = NULL; |
1195 | } |
1196 | kretprobe_table_unlock(hash, &flags); |
1197 | } |
1198 | free_rp_inst(rp); |
1199 | } |
1200 | NOKPROBE_SYMBOL(cleanup_rp_inst); |
1201 | |
1202 | /* |
1203 | * Add the new probe to ap->list. Fail if this is the |
1204 | * second jprobe at the address - two jprobes can't coexist |
1205 | */ |
1206 | static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
1207 | { |
1208 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
1209 | |
1210 | if (p->break_handler || p->post_handler) |
1211 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
1212 | |
1213 | if (p->break_handler) { |
1214 | if (ap->break_handler) |
1215 | return -EEXIST; |
1216 | list_add_tail_rcu(&p->list, &ap->list); |
1217 | ap->break_handler = aggr_break_handler; |
1218 | } else |
1219 | list_add_rcu(&p->list, &ap->list); |
1220 | if (p->post_handler && !ap->post_handler) |
1221 | ap->post_handler = aggr_post_handler; |
1222 | |
1223 | return 0; |
1224 | } |
1225 | |
1226 | /* |
1227 | * Fill in the required fields of the "manager kprobe". Replace the |
1228 | * earlier kprobe in the hlist with the manager kprobe |
1229 | */ |
1230 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
1231 | { |
1232 | /* Copy p's insn slot to ap */ |
1233 | copy_kprobe(p, ap); |
1234 | flush_insn_slot(ap); |
1235 | ap->addr = p->addr; |
1236 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
1237 | ap->pre_handler = aggr_pre_handler; |
1238 | ap->fault_handler = aggr_fault_handler; |
1239 | /* We don't care the kprobe which has gone. */ |
1240 | if (p->post_handler && !kprobe_gone(p)) |
1241 | ap->post_handler = aggr_post_handler; |
1242 | if (p->break_handler && !kprobe_gone(p)) |
1243 | ap->break_handler = aggr_break_handler; |
1244 | |
1245 | INIT_LIST_HEAD(&ap->list); |
1246 | INIT_HLIST_NODE(&ap->hlist); |
1247 | |
1248 | list_add_rcu(&p->list, &ap->list); |
1249 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
1250 | } |
1251 | |
1252 | /* |
1253 | * This is the second or subsequent kprobe at the address - handle |
1254 | * the intricacies |
1255 | */ |
1256 | static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
1257 | { |
1258 | int ret = 0; |
1259 | struct kprobe *ap = orig_p; |
1260 | |
1261 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1262 | jump_label_lock(); |
1263 | /* |
1264 | * Get online CPUs to avoid text_mutex deadlock.with stop machine, |
1265 | * which is invoked by unoptimize_kprobe() in add_new_kprobe() |
1266 | */ |
1267 | get_online_cpus(); |
1268 | mutex_lock(&text_mutex); |
1269 | |
1270 | if (!kprobe_aggrprobe(orig_p)) { |
1271 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ |
1272 | ap = alloc_aggr_kprobe(orig_p); |
1273 | if (!ap) { |
1274 | ret = -ENOMEM; |
1275 | goto out; |
1276 | } |
1277 | init_aggr_kprobe(ap, orig_p); |
1278 | } else if (kprobe_unused(ap)) |
1279 | /* This probe is going to die. Rescue it */ |
1280 | reuse_unused_kprobe(ap); |
1281 | |
1282 | if (kprobe_gone(ap)) { |
1283 | /* |
1284 | * Attempting to insert new probe at the same location that |
1285 | * had a probe in the module vaddr area which already |
1286 | * freed. So, the instruction slot has already been |
1287 | * released. We need a new slot for the new probe. |
1288 | */ |
1289 | ret = arch_prepare_kprobe(ap); |
1290 | if (ret) |
1291 | /* |
1292 | * Even if fail to allocate new slot, don't need to |
1293 | * free aggr_probe. It will be used next time, or |
1294 | * freed by unregister_kprobe. |
1295 | */ |
1296 | goto out; |
1297 | |
1298 | /* Prepare optimized instructions if possible. */ |
1299 | prepare_optimized_kprobe(ap); |
1300 | |
1301 | /* |
1302 | * Clear gone flag to prevent allocating new slot again, and |
1303 | * set disabled flag because it is not armed yet. |
1304 | */ |
1305 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1306 | | KPROBE_FLAG_DISABLED; |
1307 | } |
1308 | |
1309 | /* Copy ap's insn slot to p */ |
1310 | copy_kprobe(ap, p); |
1311 | ret = add_new_kprobe(ap, p); |
1312 | |
1313 | out: |
1314 | mutex_unlock(&text_mutex); |
1315 | put_online_cpus(); |
1316 | jump_label_unlock(); |
1317 | |
1318 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { |
1319 | ap->flags &= ~KPROBE_FLAG_DISABLED; |
1320 | if (!kprobes_all_disarmed) |
1321 | /* Arm the breakpoint again. */ |
1322 | arm_kprobe(ap); |
1323 | } |
1324 | return ret; |
1325 | } |
1326 | |
1327 | bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
1328 | { |
1329 | /* The __kprobes marked functions and entry code must not be probed */ |
1330 | return addr >= (unsigned long)__kprobes_text_start && |
1331 | addr < (unsigned long)__kprobes_text_end; |
1332 | } |
1333 | |
1334 | static bool within_kprobe_blacklist(unsigned long addr) |
1335 | { |
1336 | struct kprobe_blacklist_entry *ent; |
1337 | |
1338 | if (arch_within_kprobe_blacklist(addr)) |
1339 | return true; |
1340 | /* |
1341 | * If there exists a kprobe_blacklist, verify and |
1342 | * fail any probe registration in the prohibited area |
1343 | */ |
1344 | list_for_each_entry(ent, &kprobe_blacklist, list) { |
1345 | if (addr >= ent->start_addr && addr < ent->end_addr) |
1346 | return true; |
1347 | } |
1348 | |
1349 | return false; |
1350 | } |
1351 | |
1352 | /* |
1353 | * If we have a symbol_name argument, look it up and add the offset field |
1354 | * to it. This way, we can specify a relative address to a symbol. |
1355 | * This returns encoded errors if it fails to look up symbol or invalid |
1356 | * combination of parameters. |
1357 | */ |
1358 | static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
1359 | { |
1360 | kprobe_opcode_t *addr = p->addr; |
1361 | |
1362 | if ((p->symbol_name && p->addr) || |
1363 | (!p->symbol_name && !p->addr)) |
1364 | goto invalid; |
1365 | |
1366 | if (p->symbol_name) { |
1367 | kprobe_lookup_name(p->symbol_name, addr); |
1368 | if (!addr) |
1369 | return ERR_PTR(-ENOENT); |
1370 | } |
1371 | |
1372 | addr = (kprobe_opcode_t *)(((char *)addr) + p->offset); |
1373 | if (addr) |
1374 | return addr; |
1375 | |
1376 | invalid: |
1377 | return ERR_PTR(-EINVAL); |
1378 | } |
1379 | |
1380 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1381 | static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
1382 | { |
1383 | struct kprobe *ap, *list_p; |
1384 | |
1385 | ap = get_kprobe(p->addr); |
1386 | if (unlikely(!ap)) |
1387 | return NULL; |
1388 | |
1389 | if (p != ap) { |
1390 | list_for_each_entry_rcu(list_p, &ap->list, list) |
1391 | if (list_p == p) |
1392 | /* kprobe p is a valid probe */ |
1393 | goto valid; |
1394 | return NULL; |
1395 | } |
1396 | valid: |
1397 | return ap; |
1398 | } |
1399 | |
1400 | /* Return error if the kprobe is being re-registered */ |
1401 | static inline int check_kprobe_rereg(struct kprobe *p) |
1402 | { |
1403 | int ret = 0; |
1404 | |
1405 | mutex_lock(&kprobe_mutex); |
1406 | if (__get_valid_kprobe(p)) |
1407 | ret = -EINVAL; |
1408 | mutex_unlock(&kprobe_mutex); |
1409 | |
1410 | return ret; |
1411 | } |
1412 | |
1413 | static int check_kprobe_address_safe(struct kprobe *p, |
1414 | struct module **probed_mod) |
1415 | { |
1416 | int ret = 0; |
1417 | unsigned long ftrace_addr; |
1418 | |
1419 | /* |
1420 | * If the address is located on a ftrace nop, set the |
1421 | * breakpoint to the following instruction. |
1422 | */ |
1423 | ftrace_addr = ftrace_location((unsigned long)p->addr); |
1424 | if (ftrace_addr) { |
1425 | #ifdef CONFIG_KPROBES_ON_FTRACE |
1426 | /* Given address is not on the instruction boundary */ |
1427 | if ((unsigned long)p->addr != ftrace_addr) |
1428 | return -EILSEQ; |
1429 | p->flags |= KPROBE_FLAG_FTRACE; |
1430 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
1431 | return -EINVAL; |
1432 | #endif |
1433 | } |
1434 | |
1435 | jump_label_lock(); |
1436 | preempt_disable(); |
1437 | |
1438 | /* Ensure it is not in reserved area nor out of text */ |
1439 | if (!kernel_text_address((unsigned long) p->addr) || |
1440 | within_kprobe_blacklist((unsigned long) p->addr) || |
1441 | jump_label_text_reserved(p->addr, p->addr)) { |
1442 | ret = -EINVAL; |
1443 | goto out; |
1444 | } |
1445 | |
1446 | /* Check if are we probing a module */ |
1447 | *probed_mod = __module_text_address((unsigned long) p->addr); |
1448 | if (*probed_mod) { |
1449 | /* |
1450 | * We must hold a refcount of the probed module while updating |
1451 | * its code to prohibit unexpected unloading. |
1452 | */ |
1453 | if (unlikely(!try_module_get(*probed_mod))) { |
1454 | ret = -ENOENT; |
1455 | goto out; |
1456 | } |
1457 | |
1458 | /* |
1459 | * If the module freed .init.text, we couldn't insert |
1460 | * kprobes in there. |
1461 | */ |
1462 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
1463 | (*probed_mod)->state != MODULE_STATE_COMING) { |
1464 | module_put(*probed_mod); |
1465 | *probed_mod = NULL; |
1466 | ret = -ENOENT; |
1467 | } |
1468 | } |
1469 | out: |
1470 | preempt_enable(); |
1471 | jump_label_unlock(); |
1472 | |
1473 | return ret; |
1474 | } |
1475 | |
1476 | int register_kprobe(struct kprobe *p) |
1477 | { |
1478 | int ret; |
1479 | struct kprobe *old_p; |
1480 | struct module *probed_mod; |
1481 | kprobe_opcode_t *addr; |
1482 | |
1483 | /* Adjust probe address from symbol */ |
1484 | addr = kprobe_addr(p); |
1485 | if (IS_ERR(addr)) |
1486 | return PTR_ERR(addr); |
1487 | p->addr = addr; |
1488 | |
1489 | ret = check_kprobe_rereg(p); |
1490 | if (ret) |
1491 | return ret; |
1492 | |
1493 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
1494 | p->flags &= KPROBE_FLAG_DISABLED; |
1495 | p->nmissed = 0; |
1496 | INIT_LIST_HEAD(&p->list); |
1497 | |
1498 | ret = check_kprobe_address_safe(p, &probed_mod); |
1499 | if (ret) |
1500 | return ret; |
1501 | |
1502 | mutex_lock(&kprobe_mutex); |
1503 | |
1504 | old_p = get_kprobe(p->addr); |
1505 | if (old_p) { |
1506 | /* Since this may unoptimize old_p, locking text_mutex. */ |
1507 | ret = register_aggr_kprobe(old_p, p); |
1508 | goto out; |
1509 | } |
1510 | |
1511 | mutex_lock(&text_mutex); /* Avoiding text modification */ |
1512 | ret = prepare_kprobe(p); |
1513 | mutex_unlock(&text_mutex); |
1514 | if (ret) |
1515 | goto out; |
1516 | |
1517 | INIT_HLIST_NODE(&p->hlist); |
1518 | hlist_add_head_rcu(&p->hlist, |
1519 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1520 | |
1521 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
1522 | arm_kprobe(p); |
1523 | |
1524 | /* Try to optimize kprobe */ |
1525 | try_to_optimize_kprobe(p); |
1526 | |
1527 | out: |
1528 | mutex_unlock(&kprobe_mutex); |
1529 | |
1530 | if (probed_mod) |
1531 | module_put(probed_mod); |
1532 | |
1533 | return ret; |
1534 | } |
1535 | EXPORT_SYMBOL_GPL(register_kprobe); |
1536 | |
1537 | /* Check if all probes on the aggrprobe are disabled */ |
1538 | static int aggr_kprobe_disabled(struct kprobe *ap) |
1539 | { |
1540 | struct kprobe *kp; |
1541 | |
1542 | list_for_each_entry_rcu(kp, &ap->list, list) |
1543 | if (!kprobe_disabled(kp)) |
1544 | /* |
1545 | * There is an active probe on the list. |
1546 | * We can't disable this ap. |
1547 | */ |
1548 | return 0; |
1549 | |
1550 | return 1; |
1551 | } |
1552 | |
1553 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ |
1554 | static struct kprobe *__disable_kprobe(struct kprobe *p) |
1555 | { |
1556 | struct kprobe *orig_p; |
1557 | |
1558 | /* Get an original kprobe for return */ |
1559 | orig_p = __get_valid_kprobe(p); |
1560 | if (unlikely(orig_p == NULL)) |
1561 | return NULL; |
1562 | |
1563 | if (!kprobe_disabled(p)) { |
1564 | /* Disable probe if it is a child probe */ |
1565 | if (p != orig_p) |
1566 | p->flags |= KPROBE_FLAG_DISABLED; |
1567 | |
1568 | /* Try to disarm and disable this/parent probe */ |
1569 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { |
1570 | disarm_kprobe(orig_p, true); |
1571 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1572 | } |
1573 | } |
1574 | |
1575 | return orig_p; |
1576 | } |
1577 | |
1578 | /* |
1579 | * Unregister a kprobe without a scheduler synchronization. |
1580 | */ |
1581 | static int __unregister_kprobe_top(struct kprobe *p) |
1582 | { |
1583 | struct kprobe *ap, *list_p; |
1584 | |
1585 | /* Disable kprobe. This will disarm it if needed. */ |
1586 | ap = __disable_kprobe(p); |
1587 | if (ap == NULL) |
1588 | return -EINVAL; |
1589 | |
1590 | if (ap == p) |
1591 | /* |
1592 | * This probe is an independent(and non-optimized) kprobe |
1593 | * (not an aggrprobe). Remove from the hash list. |
1594 | */ |
1595 | goto disarmed; |
1596 | |
1597 | /* Following process expects this probe is an aggrprobe */ |
1598 | WARN_ON(!kprobe_aggrprobe(ap)); |
1599 | |
1600 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1601 | /* |
1602 | * !disarmed could be happen if the probe is under delayed |
1603 | * unoptimizing. |
1604 | */ |
1605 | goto disarmed; |
1606 | else { |
1607 | /* If disabling probe has special handlers, update aggrprobe */ |
1608 | if (p->break_handler && !kprobe_gone(p)) |
1609 | ap->break_handler = NULL; |
1610 | if (p->post_handler && !kprobe_gone(p)) { |
1611 | list_for_each_entry_rcu(list_p, &ap->list, list) { |
1612 | if ((list_p != p) && (list_p->post_handler)) |
1613 | goto noclean; |
1614 | } |
1615 | ap->post_handler = NULL; |
1616 | } |
1617 | noclean: |
1618 | /* |
1619 | * Remove from the aggrprobe: this path will do nothing in |
1620 | * __unregister_kprobe_bottom(). |
1621 | */ |
1622 | list_del_rcu(&p->list); |
1623 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1624 | /* |
1625 | * Try to optimize this probe again, because post |
1626 | * handler may have been changed. |
1627 | */ |
1628 | optimize_kprobe(ap); |
1629 | } |
1630 | return 0; |
1631 | |
1632 | disarmed: |
1633 | BUG_ON(!kprobe_disarmed(ap)); |
1634 | hlist_del_rcu(&ap->hlist); |
1635 | return 0; |
1636 | } |
1637 | |
1638 | static void __unregister_kprobe_bottom(struct kprobe *p) |
1639 | { |
1640 | struct kprobe *ap; |
1641 | |
1642 | if (list_empty(&p->list)) |
1643 | /* This is an independent kprobe */ |
1644 | arch_remove_kprobe(p); |
1645 | else if (list_is_singular(&p->list)) { |
1646 | /* This is the last child of an aggrprobe */ |
1647 | ap = list_entry(p->list.next, struct kprobe, list); |
1648 | list_del(&p->list); |
1649 | free_aggr_kprobe(ap); |
1650 | } |
1651 | /* Otherwise, do nothing. */ |
1652 | } |
1653 | |
1654 | int register_kprobes(struct kprobe **kps, int num) |
1655 | { |
1656 | int i, ret = 0; |
1657 | |
1658 | if (num <= 0) |
1659 | return -EINVAL; |
1660 | for (i = 0; i < num; i++) { |
1661 | ret = register_kprobe(kps[i]); |
1662 | if (ret < 0) { |
1663 | if (i > 0) |
1664 | unregister_kprobes(kps, i); |
1665 | break; |
1666 | } |
1667 | } |
1668 | return ret; |
1669 | } |
1670 | EXPORT_SYMBOL_GPL(register_kprobes); |
1671 | |
1672 | void unregister_kprobe(struct kprobe *p) |
1673 | { |
1674 | unregister_kprobes(&p, 1); |
1675 | } |
1676 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
1677 | |
1678 | void unregister_kprobes(struct kprobe **kps, int num) |
1679 | { |
1680 | int i; |
1681 | |
1682 | if (num <= 0) |
1683 | return; |
1684 | mutex_lock(&kprobe_mutex); |
1685 | for (i = 0; i < num; i++) |
1686 | if (__unregister_kprobe_top(kps[i]) < 0) |
1687 | kps[i]->addr = NULL; |
1688 | mutex_unlock(&kprobe_mutex); |
1689 | |
1690 | synchronize_sched(); |
1691 | for (i = 0; i < num; i++) |
1692 | if (kps[i]->addr) |
1693 | __unregister_kprobe_bottom(kps[i]); |
1694 | } |
1695 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1696 | |
1697 | static struct notifier_block kprobe_exceptions_nb = { |
1698 | .notifier_call = kprobe_exceptions_notify, |
1699 | .priority = 0x7fffffff /* we need to be notified first */ |
1700 | }; |
1701 | |
1702 | unsigned long __weak arch_deref_entry_point(void *entry) |
1703 | { |
1704 | return (unsigned long)entry; |
1705 | } |
1706 | |
1707 | int register_jprobes(struct jprobe **jps, int num) |
1708 | { |
1709 | struct jprobe *jp; |
1710 | int ret = 0, i; |
1711 | |
1712 | if (num <= 0) |
1713 | return -EINVAL; |
1714 | for (i = 0; i < num; i++) { |
1715 | unsigned long addr, offset; |
1716 | jp = jps[i]; |
1717 | addr = arch_deref_entry_point(jp->entry); |
1718 | |
1719 | /* Verify probepoint is a function entry point */ |
1720 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && |
1721 | offset == 0) { |
1722 | jp->kp.pre_handler = setjmp_pre_handler; |
1723 | jp->kp.break_handler = longjmp_break_handler; |
1724 | ret = register_kprobe(&jp->kp); |
1725 | } else |
1726 | ret = -EINVAL; |
1727 | |
1728 | if (ret < 0) { |
1729 | if (i > 0) |
1730 | unregister_jprobes(jps, i); |
1731 | break; |
1732 | } |
1733 | } |
1734 | return ret; |
1735 | } |
1736 | EXPORT_SYMBOL_GPL(register_jprobes); |
1737 | |
1738 | int register_jprobe(struct jprobe *jp) |
1739 | { |
1740 | return register_jprobes(&jp, 1); |
1741 | } |
1742 | EXPORT_SYMBOL_GPL(register_jprobe); |
1743 | |
1744 | void unregister_jprobe(struct jprobe *jp) |
1745 | { |
1746 | unregister_jprobes(&jp, 1); |
1747 | } |
1748 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
1749 | |
1750 | void unregister_jprobes(struct jprobe **jps, int num) |
1751 | { |
1752 | int i; |
1753 | |
1754 | if (num <= 0) |
1755 | return; |
1756 | mutex_lock(&kprobe_mutex); |
1757 | for (i = 0; i < num; i++) |
1758 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) |
1759 | jps[i]->kp.addr = NULL; |
1760 | mutex_unlock(&kprobe_mutex); |
1761 | |
1762 | synchronize_sched(); |
1763 | for (i = 0; i < num; i++) { |
1764 | if (jps[i]->kp.addr) |
1765 | __unregister_kprobe_bottom(&jps[i]->kp); |
1766 | } |
1767 | } |
1768 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1769 | |
1770 | #ifdef CONFIG_KRETPROBES |
1771 | /* |
1772 | * This kprobe pre_handler is registered with every kretprobe. When probe |
1773 | * hits it will set up the return probe. |
1774 | */ |
1775 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
1776 | { |
1777 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
1778 | unsigned long hash, flags = 0; |
1779 | struct kretprobe_instance *ri; |
1780 | |
1781 | /*TODO: consider to only swap the RA after the last pre_handler fired */ |
1782 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
1783 | raw_spin_lock_irqsave(&rp->lock, flags); |
1784 | if (!hlist_empty(&rp->free_instances)) { |
1785 | ri = hlist_entry(rp->free_instances.first, |
1786 | struct kretprobe_instance, hlist); |
1787 | hlist_del(&ri->hlist); |
1788 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
1789 | |
1790 | ri->rp = rp; |
1791 | ri->task = current; |
1792 | |
1793 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1794 | raw_spin_lock_irqsave(&rp->lock, flags); |
1795 | hlist_add_head(&ri->hlist, &rp->free_instances); |
1796 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
1797 | return 0; |
1798 | } |
1799 | |
1800 | arch_prepare_kretprobe(ri, regs); |
1801 | |
1802 | /* XXX(hch): why is there no hlist_move_head? */ |
1803 | INIT_HLIST_NODE(&ri->hlist); |
1804 | kretprobe_table_lock(hash, &flags); |
1805 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); |
1806 | kretprobe_table_unlock(hash, &flags); |
1807 | } else { |
1808 | rp->nmissed++; |
1809 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
1810 | } |
1811 | return 0; |
1812 | } |
1813 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
1814 | |
1815 | int register_kretprobe(struct kretprobe *rp) |
1816 | { |
1817 | int ret = 0; |
1818 | struct kretprobe_instance *inst; |
1819 | int i; |
1820 | void *addr; |
1821 | |
1822 | if (kretprobe_blacklist_size) { |
1823 | addr = kprobe_addr(&rp->kp); |
1824 | if (IS_ERR(addr)) |
1825 | return PTR_ERR(addr); |
1826 | |
1827 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1828 | if (kretprobe_blacklist[i].addr == addr) |
1829 | return -EINVAL; |
1830 | } |
1831 | } |
1832 | |
1833 | rp->kp.pre_handler = pre_handler_kretprobe; |
1834 | rp->kp.post_handler = NULL; |
1835 | rp->kp.fault_handler = NULL; |
1836 | rp->kp.break_handler = NULL; |
1837 | |
1838 | /* Pre-allocate memory for max kretprobe instances */ |
1839 | if (rp->maxactive <= 0) { |
1840 | #ifdef CONFIG_PREEMPT |
1841 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
1842 | #else |
1843 | rp->maxactive = num_possible_cpus(); |
1844 | #endif |
1845 | } |
1846 | raw_spin_lock_init(&rp->lock); |
1847 | INIT_HLIST_HEAD(&rp->free_instances); |
1848 | for (i = 0; i < rp->maxactive; i++) { |
1849 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1850 | rp->data_size, GFP_KERNEL); |
1851 | if (inst == NULL) { |
1852 | free_rp_inst(rp); |
1853 | return -ENOMEM; |
1854 | } |
1855 | INIT_HLIST_NODE(&inst->hlist); |
1856 | hlist_add_head(&inst->hlist, &rp->free_instances); |
1857 | } |
1858 | |
1859 | rp->nmissed = 0; |
1860 | /* Establish function entry probe point */ |
1861 | ret = register_kprobe(&rp->kp); |
1862 | if (ret != 0) |
1863 | free_rp_inst(rp); |
1864 | return ret; |
1865 | } |
1866 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1867 | |
1868 | int register_kretprobes(struct kretprobe **rps, int num) |
1869 | { |
1870 | int ret = 0, i; |
1871 | |
1872 | if (num <= 0) |
1873 | return -EINVAL; |
1874 | for (i = 0; i < num; i++) { |
1875 | ret = register_kretprobe(rps[i]); |
1876 | if (ret < 0) { |
1877 | if (i > 0) |
1878 | unregister_kretprobes(rps, i); |
1879 | break; |
1880 | } |
1881 | } |
1882 | return ret; |
1883 | } |
1884 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1885 | |
1886 | void unregister_kretprobe(struct kretprobe *rp) |
1887 | { |
1888 | unregister_kretprobes(&rp, 1); |
1889 | } |
1890 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1891 | |
1892 | void unregister_kretprobes(struct kretprobe **rps, int num) |
1893 | { |
1894 | int i; |
1895 | |
1896 | if (num <= 0) |
1897 | return; |
1898 | mutex_lock(&kprobe_mutex); |
1899 | for (i = 0; i < num; i++) |
1900 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
1901 | rps[i]->kp.addr = NULL; |
1902 | mutex_unlock(&kprobe_mutex); |
1903 | |
1904 | synchronize_sched(); |
1905 | for (i = 0; i < num; i++) { |
1906 | if (rps[i]->kp.addr) { |
1907 | __unregister_kprobe_bottom(&rps[i]->kp); |
1908 | cleanup_rp_inst(rps[i]); |
1909 | } |
1910 | } |
1911 | } |
1912 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1913 | |
1914 | #else /* CONFIG_KRETPROBES */ |
1915 | int register_kretprobe(struct kretprobe *rp) |
1916 | { |
1917 | return -ENOSYS; |
1918 | } |
1919 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1920 | |
1921 | int register_kretprobes(struct kretprobe **rps, int num) |
1922 | { |
1923 | return -ENOSYS; |
1924 | } |
1925 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1926 | |
1927 | void unregister_kretprobe(struct kretprobe *rp) |
1928 | { |
1929 | } |
1930 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1931 | |
1932 | void unregister_kretprobes(struct kretprobe **rps, int num) |
1933 | { |
1934 | } |
1935 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1936 | |
1937 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
1938 | { |
1939 | return 0; |
1940 | } |
1941 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
1942 | |
1943 | #endif /* CONFIG_KRETPROBES */ |
1944 | |
1945 | /* Set the kprobe gone and remove its instruction buffer. */ |
1946 | static void kill_kprobe(struct kprobe *p) |
1947 | { |
1948 | struct kprobe *kp; |
1949 | |
1950 | p->flags |= KPROBE_FLAG_GONE; |
1951 | if (kprobe_aggrprobe(p)) { |
1952 | /* |
1953 | * If this is an aggr_kprobe, we have to list all the |
1954 | * chained probes and mark them GONE. |
1955 | */ |
1956 | list_for_each_entry_rcu(kp, &p->list, list) |
1957 | kp->flags |= KPROBE_FLAG_GONE; |
1958 | p->post_handler = NULL; |
1959 | p->break_handler = NULL; |
1960 | kill_optimized_kprobe(p); |
1961 | } |
1962 | /* |
1963 | * Here, we can remove insn_slot safely, because no thread calls |
1964 | * the original probed function (which will be freed soon) any more. |
1965 | */ |
1966 | arch_remove_kprobe(p); |
1967 | } |
1968 | |
1969 | /* Disable one kprobe */ |
1970 | int disable_kprobe(struct kprobe *kp) |
1971 | { |
1972 | int ret = 0; |
1973 | |
1974 | mutex_lock(&kprobe_mutex); |
1975 | |
1976 | /* Disable this kprobe */ |
1977 | if (__disable_kprobe(kp) == NULL) |
1978 | ret = -EINVAL; |
1979 | |
1980 | mutex_unlock(&kprobe_mutex); |
1981 | return ret; |
1982 | } |
1983 | EXPORT_SYMBOL_GPL(disable_kprobe); |
1984 | |
1985 | /* Enable one kprobe */ |
1986 | int enable_kprobe(struct kprobe *kp) |
1987 | { |
1988 | int ret = 0; |
1989 | struct kprobe *p; |
1990 | |
1991 | mutex_lock(&kprobe_mutex); |
1992 | |
1993 | /* Check whether specified probe is valid. */ |
1994 | p = __get_valid_kprobe(kp); |
1995 | if (unlikely(p == NULL)) { |
1996 | ret = -EINVAL; |
1997 | goto out; |
1998 | } |
1999 | |
2000 | if (kprobe_gone(kp)) { |
2001 | /* This kprobe has gone, we couldn't enable it. */ |
2002 | ret = -EINVAL; |
2003 | goto out; |
2004 | } |
2005 | |
2006 | if (p != kp) |
2007 | kp->flags &= ~KPROBE_FLAG_DISABLED; |
2008 | |
2009 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { |
2010 | p->flags &= ~KPROBE_FLAG_DISABLED; |
2011 | arm_kprobe(p); |
2012 | } |
2013 | out: |
2014 | mutex_unlock(&kprobe_mutex); |
2015 | return ret; |
2016 | } |
2017 | EXPORT_SYMBOL_GPL(enable_kprobe); |
2018 | |
2019 | void dump_kprobe(struct kprobe *kp) |
2020 | { |
2021 | printk(KERN_WARNING "Dumping kprobe:\n"); |
2022 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", |
2023 | kp->symbol_name, kp->addr, kp->offset); |
2024 | } |
2025 | NOKPROBE_SYMBOL(dump_kprobe); |
2026 | |
2027 | /* |
2028 | * Lookup and populate the kprobe_blacklist. |
2029 | * |
2030 | * Unlike the kretprobe blacklist, we'll need to determine |
2031 | * the range of addresses that belong to the said functions, |
2032 | * since a kprobe need not necessarily be at the beginning |
2033 | * of a function. |
2034 | */ |
2035 | static int __init populate_kprobe_blacklist(unsigned long *start, |
2036 | unsigned long *end) |
2037 | { |
2038 | unsigned long *iter; |
2039 | struct kprobe_blacklist_entry *ent; |
2040 | unsigned long entry, offset = 0, size = 0; |
2041 | |
2042 | for (iter = start; iter < end; iter++) { |
2043 | entry = arch_deref_entry_point((void *)*iter); |
2044 | |
2045 | if (!kernel_text_address(entry) || |
2046 | !kallsyms_lookup_size_offset(entry, &size, &offset)) { |
2047 | pr_err("Failed to find blacklist at %p\n", |
2048 | (void *)entry); |
2049 | continue; |
2050 | } |
2051 | |
2052 | ent = kmalloc(sizeof(*ent), GFP_KERNEL); |
2053 | if (!ent) |
2054 | return -ENOMEM; |
2055 | ent->start_addr = entry; |
2056 | ent->end_addr = entry + size; |
2057 | INIT_LIST_HEAD(&ent->list); |
2058 | list_add_tail(&ent->list, &kprobe_blacklist); |
2059 | } |
2060 | return 0; |
2061 | } |
2062 | |
2063 | /* Module notifier call back, checking kprobes on the module */ |
2064 | static int kprobes_module_callback(struct notifier_block *nb, |
2065 | unsigned long val, void *data) |
2066 | { |
2067 | struct module *mod = data; |
2068 | struct hlist_head *head; |
2069 | struct kprobe *p; |
2070 | unsigned int i; |
2071 | int checkcore = (val == MODULE_STATE_GOING); |
2072 | |
2073 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
2074 | return NOTIFY_DONE; |
2075 | |
2076 | /* |
2077 | * When MODULE_STATE_GOING was notified, both of module .text and |
2078 | * .init.text sections would be freed. When MODULE_STATE_LIVE was |
2079 | * notified, only .init.text section would be freed. We need to |
2080 | * disable kprobes which have been inserted in the sections. |
2081 | */ |
2082 | mutex_lock(&kprobe_mutex); |
2083 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2084 | head = &kprobe_table[i]; |
2085 | hlist_for_each_entry_rcu(p, head, hlist) |
2086 | if (within_module_init((unsigned long)p->addr, mod) || |
2087 | (checkcore && |
2088 | within_module_core((unsigned long)p->addr, mod))) { |
2089 | /* |
2090 | * The vaddr this probe is installed will soon |
2091 | * be vfreed buy not synced to disk. Hence, |
2092 | * disarming the breakpoint isn't needed. |
2093 | */ |
2094 | kill_kprobe(p); |
2095 | } |
2096 | } |
2097 | mutex_unlock(&kprobe_mutex); |
2098 | return NOTIFY_DONE; |
2099 | } |
2100 | |
2101 | static struct notifier_block kprobe_module_nb = { |
2102 | .notifier_call = kprobes_module_callback, |
2103 | .priority = 0 |
2104 | }; |
2105 | |
2106 | /* Markers of _kprobe_blacklist section */ |
2107 | extern unsigned long __start_kprobe_blacklist[]; |
2108 | extern unsigned long __stop_kprobe_blacklist[]; |
2109 | |
2110 | static int __init init_kprobes(void) |
2111 | { |
2112 | int i, err = 0; |
2113 | |
2114 | /* FIXME allocate the probe table, currently defined statically */ |
2115 | /* initialize all list heads */ |
2116 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2117 | INIT_HLIST_HEAD(&kprobe_table[i]); |
2118 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
2119 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
2120 | } |
2121 | |
2122 | err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
2123 | __stop_kprobe_blacklist); |
2124 | if (err) { |
2125 | pr_err("kprobes: failed to populate blacklist: %d\n", err); |
2126 | pr_err("Please take care of using kprobes.\n"); |
2127 | } |
2128 | |
2129 | if (kretprobe_blacklist_size) { |
2130 | /* lookup the function address from its name */ |
2131 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
2132 | kprobe_lookup_name(kretprobe_blacklist[i].name, |
2133 | kretprobe_blacklist[i].addr); |
2134 | if (!kretprobe_blacklist[i].addr) |
2135 | printk("kretprobe: lookup failed: %s\n", |
2136 | kretprobe_blacklist[i].name); |
2137 | } |
2138 | } |
2139 | |
2140 | #if defined(CONFIG_OPTPROBES) |
2141 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
2142 | /* Init kprobe_optinsn_slots */ |
2143 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
2144 | #endif |
2145 | /* By default, kprobes can be optimized */ |
2146 | kprobes_allow_optimization = true; |
2147 | #endif |
2148 | |
2149 | /* By default, kprobes are armed */ |
2150 | kprobes_all_disarmed = false; |
2151 | |
2152 | err = arch_init_kprobes(); |
2153 | if (!err) |
2154 | err = register_die_notifier(&kprobe_exceptions_nb); |
2155 | if (!err) |
2156 | err = register_module_notifier(&kprobe_module_nb); |
2157 | |
2158 | kprobes_initialized = (err == 0); |
2159 | |
2160 | if (!err) |
2161 | init_test_probes(); |
2162 | return err; |
2163 | } |
2164 | |
2165 | #ifdef CONFIG_DEBUG_FS |
2166 | static void report_probe(struct seq_file *pi, struct kprobe *p, |
2167 | const char *sym, int offset, char *modname, struct kprobe *pp) |
2168 | { |
2169 | char *kprobe_type; |
2170 | |
2171 | if (p->pre_handler == pre_handler_kretprobe) |
2172 | kprobe_type = "r"; |
2173 | else if (p->pre_handler == setjmp_pre_handler) |
2174 | kprobe_type = "j"; |
2175 | else |
2176 | kprobe_type = "k"; |
2177 | |
2178 | if (sym) |
2179 | seq_printf(pi, "%p %s %s+0x%x %s ", |
2180 | p->addr, kprobe_type, sym, offset, |
2181 | (modname ? modname : " ")); |
2182 | else |
2183 | seq_printf(pi, "%p %s %p ", |
2184 | p->addr, kprobe_type, p->addr); |
2185 | |
2186 | if (!pp) |
2187 | pp = p; |
2188 | seq_printf(pi, "%s%s%s%s\n", |
2189 | (kprobe_gone(p) ? "[GONE]" : ""), |
2190 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), |
2191 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2192 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); |
2193 | } |
2194 | |
2195 | static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
2196 | { |
2197 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; |
2198 | } |
2199 | |
2200 | static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
2201 | { |
2202 | (*pos)++; |
2203 | if (*pos >= KPROBE_TABLE_SIZE) |
2204 | return NULL; |
2205 | return pos; |
2206 | } |
2207 | |
2208 | static void kprobe_seq_stop(struct seq_file *f, void *v) |
2209 | { |
2210 | /* Nothing to do */ |
2211 | } |
2212 | |
2213 | static int show_kprobe_addr(struct seq_file *pi, void *v) |
2214 | { |
2215 | struct hlist_head *head; |
2216 | struct kprobe *p, *kp; |
2217 | const char *sym = NULL; |
2218 | unsigned int i = *(loff_t *) v; |
2219 | unsigned long offset = 0; |
2220 | char *modname, namebuf[KSYM_NAME_LEN]; |
2221 | |
2222 | head = &kprobe_table[i]; |
2223 | preempt_disable(); |
2224 | hlist_for_each_entry_rcu(p, head, hlist) { |
2225 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
2226 | &offset, &modname, namebuf); |
2227 | if (kprobe_aggrprobe(p)) { |
2228 | list_for_each_entry_rcu(kp, &p->list, list) |
2229 | report_probe(pi, kp, sym, offset, modname, p); |
2230 | } else |
2231 | report_probe(pi, p, sym, offset, modname, NULL); |
2232 | } |
2233 | preempt_enable(); |
2234 | return 0; |
2235 | } |
2236 | |
2237 | static const struct seq_operations kprobes_seq_ops = { |
2238 | .start = kprobe_seq_start, |
2239 | .next = kprobe_seq_next, |
2240 | .stop = kprobe_seq_stop, |
2241 | .show = show_kprobe_addr |
2242 | }; |
2243 | |
2244 | static int kprobes_open(struct inode *inode, struct file *filp) |
2245 | { |
2246 | return seq_open(filp, &kprobes_seq_ops); |
2247 | } |
2248 | |
2249 | static const struct file_operations debugfs_kprobes_operations = { |
2250 | .open = kprobes_open, |
2251 | .read = seq_read, |
2252 | .llseek = seq_lseek, |
2253 | .release = seq_release, |
2254 | }; |
2255 | |
2256 | /* kprobes/blacklist -- shows which functions can not be probed */ |
2257 | static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) |
2258 | { |
2259 | return seq_list_start(&kprobe_blacklist, *pos); |
2260 | } |
2261 | |
2262 | static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) |
2263 | { |
2264 | return seq_list_next(v, &kprobe_blacklist, pos); |
2265 | } |
2266 | |
2267 | static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) |
2268 | { |
2269 | struct kprobe_blacklist_entry *ent = |
2270 | list_entry(v, struct kprobe_blacklist_entry, list); |
2271 | |
2272 | seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr, |
2273 | (void *)ent->end_addr, (void *)ent->start_addr); |
2274 | return 0; |
2275 | } |
2276 | |
2277 | static const struct seq_operations kprobe_blacklist_seq_ops = { |
2278 | .start = kprobe_blacklist_seq_start, |
2279 | .next = kprobe_blacklist_seq_next, |
2280 | .stop = kprobe_seq_stop, /* Reuse void function */ |
2281 | .show = kprobe_blacklist_seq_show, |
2282 | }; |
2283 | |
2284 | static int kprobe_blacklist_open(struct inode *inode, struct file *filp) |
2285 | { |
2286 | return seq_open(filp, &kprobe_blacklist_seq_ops); |
2287 | } |
2288 | |
2289 | static const struct file_operations debugfs_kprobe_blacklist_ops = { |
2290 | .open = kprobe_blacklist_open, |
2291 | .read = seq_read, |
2292 | .llseek = seq_lseek, |
2293 | .release = seq_release, |
2294 | }; |
2295 | |
2296 | static void arm_all_kprobes(void) |
2297 | { |
2298 | struct hlist_head *head; |
2299 | struct kprobe *p; |
2300 | unsigned int i; |
2301 | |
2302 | mutex_lock(&kprobe_mutex); |
2303 | |
2304 | /* If kprobes are armed, just return */ |
2305 | if (!kprobes_all_disarmed) |
2306 | goto already_enabled; |
2307 | |
2308 | /* Arming kprobes doesn't optimize kprobe itself */ |
2309 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2310 | head = &kprobe_table[i]; |
2311 | hlist_for_each_entry_rcu(p, head, hlist) |
2312 | if (!kprobe_disabled(p)) |
2313 | arm_kprobe(p); |
2314 | } |
2315 | |
2316 | kprobes_all_disarmed = false; |
2317 | printk(KERN_INFO "Kprobes globally enabled\n"); |
2318 | |
2319 | already_enabled: |
2320 | mutex_unlock(&kprobe_mutex); |
2321 | return; |
2322 | } |
2323 | |
2324 | static void disarm_all_kprobes(void) |
2325 | { |
2326 | struct hlist_head *head; |
2327 | struct kprobe *p; |
2328 | unsigned int i; |
2329 | |
2330 | mutex_lock(&kprobe_mutex); |
2331 | |
2332 | /* If kprobes are already disarmed, just return */ |
2333 | if (kprobes_all_disarmed) { |
2334 | mutex_unlock(&kprobe_mutex); |
2335 | return; |
2336 | } |
2337 | |
2338 | kprobes_all_disarmed = true; |
2339 | printk(KERN_INFO "Kprobes globally disabled\n"); |
2340 | |
2341 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2342 | head = &kprobe_table[i]; |
2343 | hlist_for_each_entry_rcu(p, head, hlist) { |
2344 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
2345 | disarm_kprobe(p, false); |
2346 | } |
2347 | } |
2348 | mutex_unlock(&kprobe_mutex); |
2349 | |
2350 | /* Wait for disarming all kprobes by optimizer */ |
2351 | wait_for_kprobe_optimizer(); |
2352 | } |
2353 | |
2354 | /* |
2355 | * XXX: The debugfs bool file interface doesn't allow for callbacks |
2356 | * when the bool state is switched. We can reuse that facility when |
2357 | * available |
2358 | */ |
2359 | static ssize_t read_enabled_file_bool(struct file *file, |
2360 | char __user *user_buf, size_t count, loff_t *ppos) |
2361 | { |
2362 | char buf[3]; |
2363 | |
2364 | if (!kprobes_all_disarmed) |
2365 | buf[0] = '1'; |
2366 | else |
2367 | buf[0] = '0'; |
2368 | buf[1] = '\n'; |
2369 | buf[2] = 0x00; |
2370 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); |
2371 | } |
2372 | |
2373 | static ssize_t write_enabled_file_bool(struct file *file, |
2374 | const char __user *user_buf, size_t count, loff_t *ppos) |
2375 | { |
2376 | char buf[32]; |
2377 | size_t buf_size; |
2378 | |
2379 | buf_size = min(count, (sizeof(buf)-1)); |
2380 | if (copy_from_user(buf, user_buf, buf_size)) |
2381 | return -EFAULT; |
2382 | |
2383 | buf[buf_size] = '\0'; |
2384 | switch (buf[0]) { |
2385 | case 'y': |
2386 | case 'Y': |
2387 | case '1': |
2388 | arm_all_kprobes(); |
2389 | break; |
2390 | case 'n': |
2391 | case 'N': |
2392 | case '0': |
2393 | disarm_all_kprobes(); |
2394 | break; |
2395 | default: |
2396 | return -EINVAL; |
2397 | } |
2398 | |
2399 | return count; |
2400 | } |
2401 | |
2402 | static const struct file_operations fops_kp = { |
2403 | .read = read_enabled_file_bool, |
2404 | .write = write_enabled_file_bool, |
2405 | .llseek = default_llseek, |
2406 | }; |
2407 | |
2408 | static int __init debugfs_kprobe_init(void) |
2409 | { |
2410 | struct dentry *dir, *file; |
2411 | unsigned int value = 1; |
2412 | |
2413 | dir = debugfs_create_dir("kprobes", NULL); |
2414 | if (!dir) |
2415 | return -ENOMEM; |
2416 | |
2417 | file = debugfs_create_file("list", 0444, dir, NULL, |
2418 | &debugfs_kprobes_operations); |
2419 | if (!file) |
2420 | goto error; |
2421 | |
2422 | file = debugfs_create_file("enabled", 0600, dir, |
2423 | &value, &fops_kp); |
2424 | if (!file) |
2425 | goto error; |
2426 | |
2427 | file = debugfs_create_file("blacklist", 0444, dir, NULL, |
2428 | &debugfs_kprobe_blacklist_ops); |
2429 | if (!file) |
2430 | goto error; |
2431 | |
2432 | return 0; |
2433 | |
2434 | error: |
2435 | debugfs_remove(dir); |
2436 | return -ENOMEM; |
2437 | } |
2438 | |
2439 | late_initcall(debugfs_kprobe_init); |
2440 | #endif /* CONFIG_DEBUG_FS */ |
2441 | |
2442 | module_init(init_kprobes); |
2443 | |
2444 | /* defined in arch/.../kernel/kprobes.c */ |
2445 | EXPORT_SYMBOL_GPL(jprobe_return); |
2446 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
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master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9