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Source at commit cdde9cf73945d547acd3e96f9508c79e84ad0bf1 created 12 years 9 months ago. By Maarten ter Huurne, MMC: JZ4740: Added support for CPU frequency changing | |
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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 | /* |
90 | * Normally, functions that we'd want to prohibit kprobes in, are marked |
91 | * __kprobes. But, there are cases where such functions already belong to |
92 | * a different section (__sched for preempt_schedule) |
93 | * |
94 | * For such cases, we now have a blacklist |
95 | */ |
96 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
97 | {"preempt_schedule",}, |
98 | {"native_get_debugreg",}, |
99 | {"irq_entries_start",}, |
100 | {"common_interrupt",}, |
101 | {"mcount",}, /* mcount can be called from everywhere */ |
102 | {NULL} /* Terminator */ |
103 | }; |
104 | |
105 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
106 | /* |
107 | * kprobe->ainsn.insn points to the copy of the instruction to be |
108 | * single-stepped. x86_64, POWER4 and above have no-exec support and |
109 | * stepping on the instruction on a vmalloced/kmalloced/data page |
110 | * is a recipe for disaster |
111 | */ |
112 | struct kprobe_insn_page { |
113 | struct list_head list; |
114 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
115 | int nused; |
116 | int ngarbage; |
117 | char slot_used[]; |
118 | }; |
119 | |
120 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
121 | (offsetof(struct kprobe_insn_page, slot_used) + \ |
122 | (sizeof(char) * (slots))) |
123 | |
124 | struct kprobe_insn_cache { |
125 | struct list_head pages; /* list of kprobe_insn_page */ |
126 | size_t insn_size; /* size of instruction slot */ |
127 | int nr_garbage; |
128 | }; |
129 | |
130 | static int slots_per_page(struct kprobe_insn_cache *c) |
131 | { |
132 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); |
133 | } |
134 | |
135 | enum kprobe_slot_state { |
136 | SLOT_CLEAN = 0, |
137 | SLOT_DIRTY = 1, |
138 | SLOT_USED = 2, |
139 | }; |
140 | |
141 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ |
142 | static struct kprobe_insn_cache kprobe_insn_slots = { |
143 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
144 | .insn_size = MAX_INSN_SIZE, |
145 | .nr_garbage = 0, |
146 | }; |
147 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); |
148 | |
149 | /** |
150 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
151 | * We allocate an executable page if there's no room on existing ones. |
152 | */ |
153 | static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
154 | { |
155 | struct kprobe_insn_page *kip; |
156 | |
157 | retry: |
158 | list_for_each_entry(kip, &c->pages, list) { |
159 | if (kip->nused < slots_per_page(c)) { |
160 | int i; |
161 | for (i = 0; i < slots_per_page(c); i++) { |
162 | if (kip->slot_used[i] == SLOT_CLEAN) { |
163 | kip->slot_used[i] = SLOT_USED; |
164 | kip->nused++; |
165 | return kip->insns + (i * c->insn_size); |
166 | } |
167 | } |
168 | /* kip->nused is broken. Fix it. */ |
169 | kip->nused = slots_per_page(c); |
170 | WARN_ON(1); |
171 | } |
172 | } |
173 | |
174 | /* If there are any garbage slots, collect it and try again. */ |
175 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
176 | goto retry; |
177 | |
178 | /* All out of space. Need to allocate a new page. */ |
179 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); |
180 | if (!kip) |
181 | return NULL; |
182 | |
183 | /* |
184 | * Use module_alloc so this page is within +/- 2GB of where the |
185 | * kernel image and loaded module images reside. This is required |
186 | * so x86_64 can correctly handle the %rip-relative fixups. |
187 | */ |
188 | kip->insns = module_alloc(PAGE_SIZE); |
189 | if (!kip->insns) { |
190 | kfree(kip); |
191 | return NULL; |
192 | } |
193 | INIT_LIST_HEAD(&kip->list); |
194 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
195 | kip->slot_used[0] = SLOT_USED; |
196 | kip->nused = 1; |
197 | kip->ngarbage = 0; |
198 | list_add(&kip->list, &c->pages); |
199 | return kip->insns; |
200 | } |
201 | |
202 | |
203 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
204 | { |
205 | kprobe_opcode_t *ret = NULL; |
206 | |
207 | mutex_lock(&kprobe_insn_mutex); |
208 | ret = __get_insn_slot(&kprobe_insn_slots); |
209 | mutex_unlock(&kprobe_insn_mutex); |
210 | |
211 | return ret; |
212 | } |
213 | |
214 | /* Return 1 if all garbages are collected, otherwise 0. */ |
215 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) |
216 | { |
217 | kip->slot_used[idx] = SLOT_CLEAN; |
218 | kip->nused--; |
219 | if (kip->nused == 0) { |
220 | /* |
221 | * Page is no longer in use. Free it unless |
222 | * it's the last one. We keep the last one |
223 | * so as not to have to set it up again the |
224 | * next time somebody inserts a probe. |
225 | */ |
226 | if (!list_is_singular(&kip->list)) { |
227 | list_del(&kip->list); |
228 | module_free(NULL, kip->insns); |
229 | kfree(kip); |
230 | } |
231 | return 1; |
232 | } |
233 | return 0; |
234 | } |
235 | |
236 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
237 | { |
238 | struct kprobe_insn_page *kip, *next; |
239 | |
240 | /* Ensure no-one is interrupted on the garbages */ |
241 | synchronize_sched(); |
242 | |
243 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
244 | int i; |
245 | if (kip->ngarbage == 0) |
246 | continue; |
247 | kip->ngarbage = 0; /* we will collect all garbages */ |
248 | for (i = 0; i < slots_per_page(c); i++) { |
249 | if (kip->slot_used[i] == SLOT_DIRTY && |
250 | collect_one_slot(kip, i)) |
251 | break; |
252 | } |
253 | } |
254 | c->nr_garbage = 0; |
255 | return 0; |
256 | } |
257 | |
258 | static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
259 | kprobe_opcode_t *slot, int dirty) |
260 | { |
261 | struct kprobe_insn_page *kip; |
262 | |
263 | list_for_each_entry(kip, &c->pages, list) { |
264 | long idx = ((long)slot - (long)kip->insns) / |
265 | (c->insn_size * sizeof(kprobe_opcode_t)); |
266 | if (idx >= 0 && idx < slots_per_page(c)) { |
267 | WARN_ON(kip->slot_used[idx] != SLOT_USED); |
268 | if (dirty) { |
269 | kip->slot_used[idx] = SLOT_DIRTY; |
270 | kip->ngarbage++; |
271 | if (++c->nr_garbage > slots_per_page(c)) |
272 | collect_garbage_slots(c); |
273 | } else |
274 | collect_one_slot(kip, idx); |
275 | return; |
276 | } |
277 | } |
278 | /* Could not free this slot. */ |
279 | WARN_ON(1); |
280 | } |
281 | |
282 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
283 | { |
284 | mutex_lock(&kprobe_insn_mutex); |
285 | __free_insn_slot(&kprobe_insn_slots, slot, dirty); |
286 | mutex_unlock(&kprobe_insn_mutex); |
287 | } |
288 | #ifdef CONFIG_OPTPROBES |
289 | /* For optimized_kprobe buffer */ |
290 | static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ |
291 | static struct kprobe_insn_cache kprobe_optinsn_slots = { |
292 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
293 | /* .insn_size is initialized later */ |
294 | .nr_garbage = 0, |
295 | }; |
296 | /* Get a slot for optimized_kprobe buffer */ |
297 | kprobe_opcode_t __kprobes *get_optinsn_slot(void) |
298 | { |
299 | kprobe_opcode_t *ret = NULL; |
300 | |
301 | mutex_lock(&kprobe_optinsn_mutex); |
302 | ret = __get_insn_slot(&kprobe_optinsn_slots); |
303 | mutex_unlock(&kprobe_optinsn_mutex); |
304 | |
305 | return ret; |
306 | } |
307 | |
308 | void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) |
309 | { |
310 | mutex_lock(&kprobe_optinsn_mutex); |
311 | __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); |
312 | mutex_unlock(&kprobe_optinsn_mutex); |
313 | } |
314 | #endif |
315 | #endif |
316 | |
317 | /* We have preemption disabled.. so it is safe to use __ versions */ |
318 | static inline void set_kprobe_instance(struct kprobe *kp) |
319 | { |
320 | __this_cpu_write(kprobe_instance, kp); |
321 | } |
322 | |
323 | static inline void reset_kprobe_instance(void) |
324 | { |
325 | __this_cpu_write(kprobe_instance, NULL); |
326 | } |
327 | |
328 | /* |
329 | * This routine is called either: |
330 | * - under the kprobe_mutex - during kprobe_[un]register() |
331 | * OR |
332 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
333 | */ |
334 | struct kprobe __kprobes *get_kprobe(void *addr) |
335 | { |
336 | struct hlist_head *head; |
337 | struct hlist_node *node; |
338 | struct kprobe *p; |
339 | |
340 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
341 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
342 | if (p->addr == addr) |
343 | return p; |
344 | } |
345 | |
346 | return NULL; |
347 | } |
348 | |
349 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
350 | |
351 | /* Return true if the kprobe is an aggregator */ |
352 | static inline int kprobe_aggrprobe(struct kprobe *p) |
353 | { |
354 | return p->pre_handler == aggr_pre_handler; |
355 | } |
356 | |
357 | /* Return true(!0) if the kprobe is unused */ |
358 | static inline int kprobe_unused(struct kprobe *p) |
359 | { |
360 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && |
361 | list_empty(&p->list); |
362 | } |
363 | |
364 | /* |
365 | * Keep all fields in the kprobe consistent |
366 | */ |
367 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
368 | { |
369 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
370 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); |
371 | } |
372 | |
373 | #ifdef CONFIG_OPTPROBES |
374 | /* NOTE: change this value only with kprobe_mutex held */ |
375 | static bool kprobes_allow_optimization; |
376 | |
377 | /* |
378 | * Call all pre_handler on the list, but ignores its return value. |
379 | * This must be called from arch-dep optimized caller. |
380 | */ |
381 | void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
382 | { |
383 | struct kprobe *kp; |
384 | |
385 | list_for_each_entry_rcu(kp, &p->list, list) { |
386 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
387 | set_kprobe_instance(kp); |
388 | kp->pre_handler(kp, regs); |
389 | } |
390 | reset_kprobe_instance(); |
391 | } |
392 | } |
393 | |
394 | /* Free optimized instructions and optimized_kprobe */ |
395 | static __kprobes void free_aggr_kprobe(struct kprobe *p) |
396 | { |
397 | struct optimized_kprobe *op; |
398 | |
399 | op = container_of(p, struct optimized_kprobe, kp); |
400 | arch_remove_optimized_kprobe(op); |
401 | arch_remove_kprobe(p); |
402 | kfree(op); |
403 | } |
404 | |
405 | /* Return true(!0) if the kprobe is ready for optimization. */ |
406 | static inline int kprobe_optready(struct kprobe *p) |
407 | { |
408 | struct optimized_kprobe *op; |
409 | |
410 | if (kprobe_aggrprobe(p)) { |
411 | op = container_of(p, struct optimized_kprobe, kp); |
412 | return arch_prepared_optinsn(&op->optinsn); |
413 | } |
414 | |
415 | return 0; |
416 | } |
417 | |
418 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
419 | static inline int kprobe_disarmed(struct kprobe *p) |
420 | { |
421 | struct optimized_kprobe *op; |
422 | |
423 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ |
424 | if (!kprobe_aggrprobe(p)) |
425 | return kprobe_disabled(p); |
426 | |
427 | op = container_of(p, struct optimized_kprobe, kp); |
428 | |
429 | return kprobe_disabled(p) && list_empty(&op->list); |
430 | } |
431 | |
432 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ |
433 | static int __kprobes kprobe_queued(struct kprobe *p) |
434 | { |
435 | struct optimized_kprobe *op; |
436 | |
437 | if (kprobe_aggrprobe(p)) { |
438 | op = container_of(p, struct optimized_kprobe, kp); |
439 | if (!list_empty(&op->list)) |
440 | return 1; |
441 | } |
442 | return 0; |
443 | } |
444 | |
445 | /* |
446 | * Return an optimized kprobe whose optimizing code replaces |
447 | * instructions including addr (exclude breakpoint). |
448 | */ |
449 | static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) |
450 | { |
451 | int i; |
452 | struct kprobe *p = NULL; |
453 | struct optimized_kprobe *op; |
454 | |
455 | /* Don't check i == 0, since that is a breakpoint case. */ |
456 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) |
457 | p = get_kprobe((void *)(addr - i)); |
458 | |
459 | if (p && kprobe_optready(p)) { |
460 | op = container_of(p, struct optimized_kprobe, kp); |
461 | if (arch_within_optimized_kprobe(op, addr)) |
462 | return p; |
463 | } |
464 | |
465 | return NULL; |
466 | } |
467 | |
468 | /* Optimization staging list, protected by kprobe_mutex */ |
469 | static LIST_HEAD(optimizing_list); |
470 | static LIST_HEAD(unoptimizing_list); |
471 | |
472 | static void kprobe_optimizer(struct work_struct *work); |
473 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); |
474 | static DECLARE_COMPLETION(optimizer_comp); |
475 | #define OPTIMIZE_DELAY 5 |
476 | |
477 | /* |
478 | * Optimize (replace a breakpoint with a jump) kprobes listed on |
479 | * optimizing_list. |
480 | */ |
481 | static __kprobes void do_optimize_kprobes(void) |
482 | { |
483 | /* Optimization never be done when disarmed */ |
484 | if (kprobes_all_disarmed || !kprobes_allow_optimization || |
485 | list_empty(&optimizing_list)) |
486 | return; |
487 | |
488 | /* |
489 | * The optimization/unoptimization refers online_cpus via |
490 | * stop_machine() and cpu-hotplug modifies online_cpus. |
491 | * And same time, text_mutex will be held in cpu-hotplug and here. |
492 | * This combination can cause a deadlock (cpu-hotplug try to lock |
493 | * text_mutex but stop_machine can not be done because online_cpus |
494 | * has been changed) |
495 | * To avoid this deadlock, we need to call get_online_cpus() |
496 | * for preventing cpu-hotplug outside of text_mutex locking. |
497 | */ |
498 | get_online_cpus(); |
499 | mutex_lock(&text_mutex); |
500 | arch_optimize_kprobes(&optimizing_list); |
501 | mutex_unlock(&text_mutex); |
502 | put_online_cpus(); |
503 | } |
504 | |
505 | /* |
506 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint |
507 | * if need) kprobes listed on unoptimizing_list. |
508 | */ |
509 | static __kprobes void do_unoptimize_kprobes(struct list_head *free_list) |
510 | { |
511 | struct optimized_kprobe *op, *tmp; |
512 | |
513 | /* Unoptimization must be done anytime */ |
514 | if (list_empty(&unoptimizing_list)) |
515 | return; |
516 | |
517 | /* Ditto to do_optimize_kprobes */ |
518 | get_online_cpus(); |
519 | mutex_lock(&text_mutex); |
520 | arch_unoptimize_kprobes(&unoptimizing_list, free_list); |
521 | /* Loop free_list for disarming */ |
522 | list_for_each_entry_safe(op, tmp, free_list, list) { |
523 | /* Disarm probes if marked disabled */ |
524 | if (kprobe_disabled(&op->kp)) |
525 | arch_disarm_kprobe(&op->kp); |
526 | if (kprobe_unused(&op->kp)) { |
527 | /* |
528 | * Remove unused probes from hash list. After waiting |
529 | * for synchronization, these probes are reclaimed. |
530 | * (reclaiming is done by do_free_cleaned_kprobes.) |
531 | */ |
532 | hlist_del_rcu(&op->kp.hlist); |
533 | } else |
534 | list_del_init(&op->list); |
535 | } |
536 | mutex_unlock(&text_mutex); |
537 | put_online_cpus(); |
538 | } |
539 | |
540 | /* Reclaim all kprobes on the free_list */ |
541 | static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list) |
542 | { |
543 | struct optimized_kprobe *op, *tmp; |
544 | |
545 | list_for_each_entry_safe(op, tmp, free_list, list) { |
546 | BUG_ON(!kprobe_unused(&op->kp)); |
547 | list_del_init(&op->list); |
548 | free_aggr_kprobe(&op->kp); |
549 | } |
550 | } |
551 | |
552 | /* Start optimizer after OPTIMIZE_DELAY passed */ |
553 | static __kprobes void kick_kprobe_optimizer(void) |
554 | { |
555 | if (!delayed_work_pending(&optimizing_work)) |
556 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
557 | } |
558 | |
559 | /* Kprobe jump optimizer */ |
560 | static __kprobes void kprobe_optimizer(struct work_struct *work) |
561 | { |
562 | LIST_HEAD(free_list); |
563 | |
564 | /* Lock modules while optimizing kprobes */ |
565 | mutex_lock(&module_mutex); |
566 | mutex_lock(&kprobe_mutex); |
567 | |
568 | /* |
569 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
570 | * kprobes before waiting for quiesence period. |
571 | */ |
572 | do_unoptimize_kprobes(&free_list); |
573 | |
574 | /* |
575 | * Step 2: Wait for quiesence period to ensure all running interrupts |
576 | * are done. Because optprobe may modify multiple instructions |
577 | * there is a chance that Nth instruction is interrupted. In that |
578 | * case, running interrupt can return to 2nd-Nth byte of jump |
579 | * instruction. This wait is for avoiding it. |
580 | */ |
581 | synchronize_sched(); |
582 | |
583 | /* Step 3: Optimize kprobes after quiesence period */ |
584 | do_optimize_kprobes(); |
585 | |
586 | /* Step 4: Free cleaned kprobes after quiesence period */ |
587 | do_free_cleaned_kprobes(&free_list); |
588 | |
589 | mutex_unlock(&kprobe_mutex); |
590 | mutex_unlock(&module_mutex); |
591 | |
592 | /* Step 5: Kick optimizer again if needed */ |
593 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
594 | kick_kprobe_optimizer(); |
595 | else |
596 | /* Wake up all waiters */ |
597 | complete_all(&optimizer_comp); |
598 | } |
599 | |
600 | /* Wait for completing optimization and unoptimization */ |
601 | static __kprobes void wait_for_kprobe_optimizer(void) |
602 | { |
603 | if (delayed_work_pending(&optimizing_work)) |
604 | wait_for_completion(&optimizer_comp); |
605 | } |
606 | |
607 | /* Optimize kprobe if p is ready to be optimized */ |
608 | static __kprobes void optimize_kprobe(struct kprobe *p) |
609 | { |
610 | struct optimized_kprobe *op; |
611 | |
612 | /* Check if the kprobe is disabled or not ready for optimization. */ |
613 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
614 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
615 | return; |
616 | |
617 | /* Both of break_handler and post_handler are not supported. */ |
618 | if (p->break_handler || p->post_handler) |
619 | return; |
620 | |
621 | op = container_of(p, struct optimized_kprobe, kp); |
622 | |
623 | /* Check there is no other kprobes at the optimized instructions */ |
624 | if (arch_check_optimized_kprobe(op) < 0) |
625 | return; |
626 | |
627 | /* Check if it is already optimized. */ |
628 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) |
629 | return; |
630 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
631 | |
632 | if (!list_empty(&op->list)) |
633 | /* This is under unoptimizing. Just dequeue the probe */ |
634 | list_del_init(&op->list); |
635 | else { |
636 | list_add(&op->list, &optimizing_list); |
637 | kick_kprobe_optimizer(); |
638 | } |
639 | } |
640 | |
641 | /* Short cut to direct unoptimizing */ |
642 | static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op) |
643 | { |
644 | get_online_cpus(); |
645 | arch_unoptimize_kprobe(op); |
646 | put_online_cpus(); |
647 | if (kprobe_disabled(&op->kp)) |
648 | arch_disarm_kprobe(&op->kp); |
649 | } |
650 | |
651 | /* Unoptimize a kprobe if p is optimized */ |
652 | static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force) |
653 | { |
654 | struct optimized_kprobe *op; |
655 | |
656 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
657 | return; /* This is not an optprobe nor optimized */ |
658 | |
659 | op = container_of(p, struct optimized_kprobe, kp); |
660 | if (!kprobe_optimized(p)) { |
661 | /* Unoptimized or unoptimizing case */ |
662 | if (force && !list_empty(&op->list)) { |
663 | /* |
664 | * Only if this is unoptimizing kprobe and forced, |
665 | * forcibly unoptimize it. (No need to unoptimize |
666 | * unoptimized kprobe again :) |
667 | */ |
668 | list_del_init(&op->list); |
669 | force_unoptimize_kprobe(op); |
670 | } |
671 | return; |
672 | } |
673 | |
674 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
675 | if (!list_empty(&op->list)) { |
676 | /* Dequeue from the optimization queue */ |
677 | list_del_init(&op->list); |
678 | return; |
679 | } |
680 | /* Optimized kprobe case */ |
681 | if (force) |
682 | /* Forcibly update the code: this is a special case */ |
683 | force_unoptimize_kprobe(op); |
684 | else { |
685 | list_add(&op->list, &unoptimizing_list); |
686 | kick_kprobe_optimizer(); |
687 | } |
688 | } |
689 | |
690 | /* Cancel unoptimizing for reusing */ |
691 | static void reuse_unused_kprobe(struct kprobe *ap) |
692 | { |
693 | struct optimized_kprobe *op; |
694 | |
695 | BUG_ON(!kprobe_unused(ap)); |
696 | /* |
697 | * Unused kprobe MUST be on the way of delayed unoptimizing (means |
698 | * there is still a relative jump) and disabled. |
699 | */ |
700 | op = container_of(ap, struct optimized_kprobe, kp); |
701 | if (unlikely(list_empty(&op->list))) |
702 | printk(KERN_WARNING "Warning: found a stray unused " |
703 | "aggrprobe@%p\n", ap->addr); |
704 | /* Enable the probe again */ |
705 | ap->flags &= ~KPROBE_FLAG_DISABLED; |
706 | /* Optimize it again (remove from op->list) */ |
707 | BUG_ON(!kprobe_optready(ap)); |
708 | optimize_kprobe(ap); |
709 | } |
710 | |
711 | /* Remove optimized instructions */ |
712 | static void __kprobes kill_optimized_kprobe(struct kprobe *p) |
713 | { |
714 | struct optimized_kprobe *op; |
715 | |
716 | op = container_of(p, struct optimized_kprobe, kp); |
717 | if (!list_empty(&op->list)) |
718 | /* Dequeue from the (un)optimization queue */ |
719 | list_del_init(&op->list); |
720 | |
721 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
722 | /* Don't touch the code, because it is already freed. */ |
723 | arch_remove_optimized_kprobe(op); |
724 | } |
725 | |
726 | /* Try to prepare optimized instructions */ |
727 | static __kprobes void prepare_optimized_kprobe(struct kprobe *p) |
728 | { |
729 | struct optimized_kprobe *op; |
730 | |
731 | op = container_of(p, struct optimized_kprobe, kp); |
732 | arch_prepare_optimized_kprobe(op); |
733 | } |
734 | |
735 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
736 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
737 | { |
738 | struct optimized_kprobe *op; |
739 | |
740 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); |
741 | if (!op) |
742 | return NULL; |
743 | |
744 | INIT_LIST_HEAD(&op->list); |
745 | op->kp.addr = p->addr; |
746 | arch_prepare_optimized_kprobe(op); |
747 | |
748 | return &op->kp; |
749 | } |
750 | |
751 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
752 | |
753 | /* |
754 | * Prepare an optimized_kprobe and optimize it |
755 | * NOTE: p must be a normal registered kprobe |
756 | */ |
757 | static __kprobes void try_to_optimize_kprobe(struct kprobe *p) |
758 | { |
759 | struct kprobe *ap; |
760 | struct optimized_kprobe *op; |
761 | |
762 | ap = alloc_aggr_kprobe(p); |
763 | if (!ap) |
764 | return; |
765 | |
766 | op = container_of(ap, struct optimized_kprobe, kp); |
767 | if (!arch_prepared_optinsn(&op->optinsn)) { |
768 | /* If failed to setup optimizing, fallback to kprobe */ |
769 | arch_remove_optimized_kprobe(op); |
770 | kfree(op); |
771 | return; |
772 | } |
773 | |
774 | init_aggr_kprobe(ap, p); |
775 | optimize_kprobe(ap); |
776 | } |
777 | |
778 | #ifdef CONFIG_SYSCTL |
779 | /* This should be called with kprobe_mutex locked */ |
780 | static void __kprobes optimize_all_kprobes(void) |
781 | { |
782 | struct hlist_head *head; |
783 | struct hlist_node *node; |
784 | struct kprobe *p; |
785 | unsigned int i; |
786 | |
787 | /* If optimization is already allowed, just return */ |
788 | if (kprobes_allow_optimization) |
789 | return; |
790 | |
791 | kprobes_allow_optimization = true; |
792 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
793 | head = &kprobe_table[i]; |
794 | hlist_for_each_entry_rcu(p, node, head, hlist) |
795 | if (!kprobe_disabled(p)) |
796 | optimize_kprobe(p); |
797 | } |
798 | printk(KERN_INFO "Kprobes globally optimized\n"); |
799 | } |
800 | |
801 | /* This should be called with kprobe_mutex locked */ |
802 | static void __kprobes unoptimize_all_kprobes(void) |
803 | { |
804 | struct hlist_head *head; |
805 | struct hlist_node *node; |
806 | struct kprobe *p; |
807 | unsigned int i; |
808 | |
809 | /* If optimization is already prohibited, just return */ |
810 | if (!kprobes_allow_optimization) |
811 | return; |
812 | |
813 | kprobes_allow_optimization = false; |
814 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
815 | head = &kprobe_table[i]; |
816 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
817 | if (!kprobe_disabled(p)) |
818 | unoptimize_kprobe(p, false); |
819 | } |
820 | } |
821 | /* Wait for unoptimizing completion */ |
822 | wait_for_kprobe_optimizer(); |
823 | printk(KERN_INFO "Kprobes globally unoptimized\n"); |
824 | } |
825 | |
826 | int sysctl_kprobes_optimization; |
827 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, |
828 | void __user *buffer, size_t *length, |
829 | loff_t *ppos) |
830 | { |
831 | int ret; |
832 | |
833 | mutex_lock(&kprobe_mutex); |
834 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
835 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); |
836 | |
837 | if (sysctl_kprobes_optimization) |
838 | optimize_all_kprobes(); |
839 | else |
840 | unoptimize_all_kprobes(); |
841 | mutex_unlock(&kprobe_mutex); |
842 | |
843 | return ret; |
844 | } |
845 | #endif /* CONFIG_SYSCTL */ |
846 | |
847 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
848 | static void __kprobes __arm_kprobe(struct kprobe *p) |
849 | { |
850 | struct kprobe *_p; |
851 | |
852 | /* Check collision with other optimized kprobes */ |
853 | _p = get_optimized_kprobe((unsigned long)p->addr); |
854 | if (unlikely(_p)) |
855 | /* Fallback to unoptimized kprobe */ |
856 | unoptimize_kprobe(_p, true); |
857 | |
858 | arch_arm_kprobe(p); |
859 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ |
860 | } |
861 | |
862 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
863 | static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt) |
864 | { |
865 | struct kprobe *_p; |
866 | |
867 | unoptimize_kprobe(p, false); /* Try to unoptimize */ |
868 | |
869 | if (!kprobe_queued(p)) { |
870 | arch_disarm_kprobe(p); |
871 | /* If another kprobe was blocked, optimize it. */ |
872 | _p = get_optimized_kprobe((unsigned long)p->addr); |
873 | if (unlikely(_p) && reopt) |
874 | optimize_kprobe(_p); |
875 | } |
876 | /* TODO: reoptimize others after unoptimized this probe */ |
877 | } |
878 | |
879 | #else /* !CONFIG_OPTPROBES */ |
880 | |
881 | #define optimize_kprobe(p) do {} while (0) |
882 | #define unoptimize_kprobe(p, f) do {} while (0) |
883 | #define kill_optimized_kprobe(p) do {} while (0) |
884 | #define prepare_optimized_kprobe(p) do {} while (0) |
885 | #define try_to_optimize_kprobe(p) do {} while (0) |
886 | #define __arm_kprobe(p) arch_arm_kprobe(p) |
887 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
888 | #define kprobe_disarmed(p) kprobe_disabled(p) |
889 | #define wait_for_kprobe_optimizer() do {} while (0) |
890 | |
891 | /* There should be no unused kprobes can be reused without optimization */ |
892 | static void reuse_unused_kprobe(struct kprobe *ap) |
893 | { |
894 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); |
895 | BUG_ON(kprobe_unused(ap)); |
896 | } |
897 | |
898 | static __kprobes void free_aggr_kprobe(struct kprobe *p) |
899 | { |
900 | arch_remove_kprobe(p); |
901 | kfree(p); |
902 | } |
903 | |
904 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
905 | { |
906 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); |
907 | } |
908 | #endif /* CONFIG_OPTPROBES */ |
909 | |
910 | /* Arm a kprobe with text_mutex */ |
911 | static void __kprobes arm_kprobe(struct kprobe *kp) |
912 | { |
913 | /* |
914 | * Here, since __arm_kprobe() doesn't use stop_machine(), |
915 | * this doesn't cause deadlock on text_mutex. So, we don't |
916 | * need get_online_cpus(). |
917 | */ |
918 | mutex_lock(&text_mutex); |
919 | __arm_kprobe(kp); |
920 | mutex_unlock(&text_mutex); |
921 | } |
922 | |
923 | /* Disarm a kprobe with text_mutex */ |
924 | static void __kprobes disarm_kprobe(struct kprobe *kp) |
925 | { |
926 | /* Ditto */ |
927 | mutex_lock(&text_mutex); |
928 | __disarm_kprobe(kp, true); |
929 | mutex_unlock(&text_mutex); |
930 | } |
931 | |
932 | /* |
933 | * Aggregate handlers for multiple kprobes support - these handlers |
934 | * take care of invoking the individual kprobe handlers on p->list |
935 | */ |
936 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
937 | { |
938 | struct kprobe *kp; |
939 | |
940 | list_for_each_entry_rcu(kp, &p->list, list) { |
941 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
942 | set_kprobe_instance(kp); |
943 | if (kp->pre_handler(kp, regs)) |
944 | return 1; |
945 | } |
946 | reset_kprobe_instance(); |
947 | } |
948 | return 0; |
949 | } |
950 | |
951 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
952 | unsigned long flags) |
953 | { |
954 | struct kprobe *kp; |
955 | |
956 | list_for_each_entry_rcu(kp, &p->list, list) { |
957 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
958 | set_kprobe_instance(kp); |
959 | kp->post_handler(kp, regs, flags); |
960 | reset_kprobe_instance(); |
961 | } |
962 | } |
963 | } |
964 | |
965 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
966 | int trapnr) |
967 | { |
968 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
969 | |
970 | /* |
971 | * if we faulted "during" the execution of a user specified |
972 | * probe handler, invoke just that probe's fault handler |
973 | */ |
974 | if (cur && cur->fault_handler) { |
975 | if (cur->fault_handler(cur, regs, trapnr)) |
976 | return 1; |
977 | } |
978 | return 0; |
979 | } |
980 | |
981 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
982 | { |
983 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
984 | int ret = 0; |
985 | |
986 | if (cur && cur->break_handler) { |
987 | if (cur->break_handler(cur, regs)) |
988 | ret = 1; |
989 | } |
990 | reset_kprobe_instance(); |
991 | return ret; |
992 | } |
993 | |
994 | /* Walks the list and increments nmissed count for multiprobe case */ |
995 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) |
996 | { |
997 | struct kprobe *kp; |
998 | if (!kprobe_aggrprobe(p)) { |
999 | p->nmissed++; |
1000 | } else { |
1001 | list_for_each_entry_rcu(kp, &p->list, list) |
1002 | kp->nmissed++; |
1003 | } |
1004 | return; |
1005 | } |
1006 | |
1007 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
1008 | struct hlist_head *head) |
1009 | { |
1010 | struct kretprobe *rp = ri->rp; |
1011 | |
1012 | /* remove rp inst off the rprobe_inst_table */ |
1013 | hlist_del(&ri->hlist); |
1014 | INIT_HLIST_NODE(&ri->hlist); |
1015 | if (likely(rp)) { |
1016 | raw_spin_lock(&rp->lock); |
1017 | hlist_add_head(&ri->hlist, &rp->free_instances); |
1018 | raw_spin_unlock(&rp->lock); |
1019 | } else |
1020 | /* Unregistering */ |
1021 | hlist_add_head(&ri->hlist, head); |
1022 | } |
1023 | |
1024 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
1025 | struct hlist_head **head, unsigned long *flags) |
1026 | __acquires(hlist_lock) |
1027 | { |
1028 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
1029 | raw_spinlock_t *hlist_lock; |
1030 | |
1031 | *head = &kretprobe_inst_table[hash]; |
1032 | hlist_lock = kretprobe_table_lock_ptr(hash); |
1033 | raw_spin_lock_irqsave(hlist_lock, *flags); |
1034 | } |
1035 | |
1036 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
1037 | unsigned long *flags) |
1038 | __acquires(hlist_lock) |
1039 | { |
1040 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1041 | raw_spin_lock_irqsave(hlist_lock, *flags); |
1042 | } |
1043 | |
1044 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
1045 | unsigned long *flags) |
1046 | __releases(hlist_lock) |
1047 | { |
1048 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
1049 | raw_spinlock_t *hlist_lock; |
1050 | |
1051 | hlist_lock = kretprobe_table_lock_ptr(hash); |
1052 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
1053 | } |
1054 | |
1055 | static void __kprobes kretprobe_table_unlock(unsigned long hash, |
1056 | unsigned long *flags) |
1057 | __releases(hlist_lock) |
1058 | { |
1059 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1060 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
1061 | } |
1062 | |
1063 | /* |
1064 | * This function is called from finish_task_switch when task tk becomes dead, |
1065 | * so that we can recycle any function-return probe instances associated |
1066 | * with this task. These left over instances represent probed functions |
1067 | * that have been called but will never return. |
1068 | */ |
1069 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
1070 | { |
1071 | struct kretprobe_instance *ri; |
1072 | struct hlist_head *head, empty_rp; |
1073 | struct hlist_node *node, *tmp; |
1074 | unsigned long hash, flags = 0; |
1075 | |
1076 | if (unlikely(!kprobes_initialized)) |
1077 | /* Early boot. kretprobe_table_locks not yet initialized. */ |
1078 | return; |
1079 | |
1080 | INIT_HLIST_HEAD(&empty_rp); |
1081 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1082 | head = &kretprobe_inst_table[hash]; |
1083 | kretprobe_table_lock(hash, &flags); |
1084 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
1085 | if (ri->task == tk) |
1086 | recycle_rp_inst(ri, &empty_rp); |
1087 | } |
1088 | kretprobe_table_unlock(hash, &flags); |
1089 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
1090 | hlist_del(&ri->hlist); |
1091 | kfree(ri); |
1092 | } |
1093 | } |
1094 | |
1095 | static inline void free_rp_inst(struct kretprobe *rp) |
1096 | { |
1097 | struct kretprobe_instance *ri; |
1098 | struct hlist_node *pos, *next; |
1099 | |
1100 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
1101 | hlist_del(&ri->hlist); |
1102 | kfree(ri); |
1103 | } |
1104 | } |
1105 | |
1106 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
1107 | { |
1108 | unsigned long flags, hash; |
1109 | struct kretprobe_instance *ri; |
1110 | struct hlist_node *pos, *next; |
1111 | struct hlist_head *head; |
1112 | |
1113 | /* No race here */ |
1114 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1115 | kretprobe_table_lock(hash, &flags); |
1116 | head = &kretprobe_inst_table[hash]; |
1117 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { |
1118 | if (ri->rp == rp) |
1119 | ri->rp = NULL; |
1120 | } |
1121 | kretprobe_table_unlock(hash, &flags); |
1122 | } |
1123 | free_rp_inst(rp); |
1124 | } |
1125 | |
1126 | /* |
1127 | * Add the new probe to ap->list. Fail if this is the |
1128 | * second jprobe at the address - two jprobes can't coexist |
1129 | */ |
1130 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
1131 | { |
1132 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
1133 | |
1134 | if (p->break_handler || p->post_handler) |
1135 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
1136 | |
1137 | if (p->break_handler) { |
1138 | if (ap->break_handler) |
1139 | return -EEXIST; |
1140 | list_add_tail_rcu(&p->list, &ap->list); |
1141 | ap->break_handler = aggr_break_handler; |
1142 | } else |
1143 | list_add_rcu(&p->list, &ap->list); |
1144 | if (p->post_handler && !ap->post_handler) |
1145 | ap->post_handler = aggr_post_handler; |
1146 | |
1147 | if (kprobe_disabled(ap) && !kprobe_disabled(p)) { |
1148 | ap->flags &= ~KPROBE_FLAG_DISABLED; |
1149 | if (!kprobes_all_disarmed) |
1150 | /* Arm the breakpoint again. */ |
1151 | __arm_kprobe(ap); |
1152 | } |
1153 | return 0; |
1154 | } |
1155 | |
1156 | /* |
1157 | * Fill in the required fields of the "manager kprobe". Replace the |
1158 | * earlier kprobe in the hlist with the manager kprobe |
1159 | */ |
1160 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
1161 | { |
1162 | /* Copy p's insn slot to ap */ |
1163 | copy_kprobe(p, ap); |
1164 | flush_insn_slot(ap); |
1165 | ap->addr = p->addr; |
1166 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
1167 | ap->pre_handler = aggr_pre_handler; |
1168 | ap->fault_handler = aggr_fault_handler; |
1169 | /* We don't care the kprobe which has gone. */ |
1170 | if (p->post_handler && !kprobe_gone(p)) |
1171 | ap->post_handler = aggr_post_handler; |
1172 | if (p->break_handler && !kprobe_gone(p)) |
1173 | ap->break_handler = aggr_break_handler; |
1174 | |
1175 | INIT_LIST_HEAD(&ap->list); |
1176 | INIT_HLIST_NODE(&ap->hlist); |
1177 | |
1178 | list_add_rcu(&p->list, &ap->list); |
1179 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
1180 | } |
1181 | |
1182 | /* |
1183 | * This is the second or subsequent kprobe at the address - handle |
1184 | * the intricacies |
1185 | */ |
1186 | static int __kprobes register_aggr_kprobe(struct kprobe *orig_p, |
1187 | struct kprobe *p) |
1188 | { |
1189 | int ret = 0; |
1190 | struct kprobe *ap = orig_p; |
1191 | |
1192 | if (!kprobe_aggrprobe(orig_p)) { |
1193 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ |
1194 | ap = alloc_aggr_kprobe(orig_p); |
1195 | if (!ap) |
1196 | return -ENOMEM; |
1197 | init_aggr_kprobe(ap, orig_p); |
1198 | } else if (kprobe_unused(ap)) |
1199 | /* This probe is going to die. Rescue it */ |
1200 | reuse_unused_kprobe(ap); |
1201 | |
1202 | if (kprobe_gone(ap)) { |
1203 | /* |
1204 | * Attempting to insert new probe at the same location that |
1205 | * had a probe in the module vaddr area which already |
1206 | * freed. So, the instruction slot has already been |
1207 | * released. We need a new slot for the new probe. |
1208 | */ |
1209 | ret = arch_prepare_kprobe(ap); |
1210 | if (ret) |
1211 | /* |
1212 | * Even if fail to allocate new slot, don't need to |
1213 | * free aggr_probe. It will be used next time, or |
1214 | * freed by unregister_kprobe. |
1215 | */ |
1216 | return ret; |
1217 | |
1218 | /* Prepare optimized instructions if possible. */ |
1219 | prepare_optimized_kprobe(ap); |
1220 | |
1221 | /* |
1222 | * Clear gone flag to prevent allocating new slot again, and |
1223 | * set disabled flag because it is not armed yet. |
1224 | */ |
1225 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1226 | | KPROBE_FLAG_DISABLED; |
1227 | } |
1228 | |
1229 | /* Copy ap's insn slot to p */ |
1230 | copy_kprobe(ap, p); |
1231 | return add_new_kprobe(ap, p); |
1232 | } |
1233 | |
1234 | static int __kprobes in_kprobes_functions(unsigned long addr) |
1235 | { |
1236 | struct kprobe_blackpoint *kb; |
1237 | |
1238 | if (addr >= (unsigned long)__kprobes_text_start && |
1239 | addr < (unsigned long)__kprobes_text_end) |
1240 | return -EINVAL; |
1241 | /* |
1242 | * If there exists a kprobe_blacklist, verify and |
1243 | * fail any probe registration in the prohibited area |
1244 | */ |
1245 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
1246 | if (kb->start_addr) { |
1247 | if (addr >= kb->start_addr && |
1248 | addr < (kb->start_addr + kb->range)) |
1249 | return -EINVAL; |
1250 | } |
1251 | } |
1252 | return 0; |
1253 | } |
1254 | |
1255 | /* |
1256 | * If we have a symbol_name argument, look it up and add the offset field |
1257 | * to it. This way, we can specify a relative address to a symbol. |
1258 | * This returns encoded errors if it fails to look up symbol or invalid |
1259 | * combination of parameters. |
1260 | */ |
1261 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) |
1262 | { |
1263 | kprobe_opcode_t *addr = p->addr; |
1264 | |
1265 | if ((p->symbol_name && p->addr) || |
1266 | (!p->symbol_name && !p->addr)) |
1267 | goto invalid; |
1268 | |
1269 | if (p->symbol_name) { |
1270 | kprobe_lookup_name(p->symbol_name, addr); |
1271 | if (!addr) |
1272 | return ERR_PTR(-ENOENT); |
1273 | } |
1274 | |
1275 | addr = (kprobe_opcode_t *)(((char *)addr) + p->offset); |
1276 | if (addr) |
1277 | return addr; |
1278 | |
1279 | invalid: |
1280 | return ERR_PTR(-EINVAL); |
1281 | } |
1282 | |
1283 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1284 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) |
1285 | { |
1286 | struct kprobe *ap, *list_p; |
1287 | |
1288 | ap = get_kprobe(p->addr); |
1289 | if (unlikely(!ap)) |
1290 | return NULL; |
1291 | |
1292 | if (p != ap) { |
1293 | list_for_each_entry_rcu(list_p, &ap->list, list) |
1294 | if (list_p == p) |
1295 | /* kprobe p is a valid probe */ |
1296 | goto valid; |
1297 | return NULL; |
1298 | } |
1299 | valid: |
1300 | return ap; |
1301 | } |
1302 | |
1303 | /* Return error if the kprobe is being re-registered */ |
1304 | static inline int check_kprobe_rereg(struct kprobe *p) |
1305 | { |
1306 | int ret = 0; |
1307 | |
1308 | mutex_lock(&kprobe_mutex); |
1309 | if (__get_valid_kprobe(p)) |
1310 | ret = -EINVAL; |
1311 | mutex_unlock(&kprobe_mutex); |
1312 | |
1313 | return ret; |
1314 | } |
1315 | |
1316 | int __kprobes register_kprobe(struct kprobe *p) |
1317 | { |
1318 | int ret = 0; |
1319 | struct kprobe *old_p; |
1320 | struct module *probed_mod; |
1321 | kprobe_opcode_t *addr; |
1322 | |
1323 | addr = kprobe_addr(p); |
1324 | if (IS_ERR(addr)) |
1325 | return PTR_ERR(addr); |
1326 | p->addr = addr; |
1327 | |
1328 | ret = check_kprobe_rereg(p); |
1329 | if (ret) |
1330 | return ret; |
1331 | |
1332 | jump_label_lock(); |
1333 | preempt_disable(); |
1334 | if (!kernel_text_address((unsigned long) p->addr) || |
1335 | in_kprobes_functions((unsigned long) p->addr) || |
1336 | ftrace_text_reserved(p->addr, p->addr) || |
1337 | jump_label_text_reserved(p->addr, p->addr)) { |
1338 | ret = -EINVAL; |
1339 | goto cannot_probe; |
1340 | } |
1341 | |
1342 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
1343 | p->flags &= KPROBE_FLAG_DISABLED; |
1344 | |
1345 | /* |
1346 | * Check if are we probing a module. |
1347 | */ |
1348 | probed_mod = __module_text_address((unsigned long) p->addr); |
1349 | if (probed_mod) { |
1350 | /* Return -ENOENT if fail. */ |
1351 | ret = -ENOENT; |
1352 | /* |
1353 | * We must hold a refcount of the probed module while updating |
1354 | * its code to prohibit unexpected unloading. |
1355 | */ |
1356 | if (unlikely(!try_module_get(probed_mod))) |
1357 | goto cannot_probe; |
1358 | |
1359 | /* |
1360 | * If the module freed .init.text, we couldn't insert |
1361 | * kprobes in there. |
1362 | */ |
1363 | if (within_module_init((unsigned long)p->addr, probed_mod) && |
1364 | probed_mod->state != MODULE_STATE_COMING) { |
1365 | module_put(probed_mod); |
1366 | goto cannot_probe; |
1367 | } |
1368 | /* ret will be updated by following code */ |
1369 | } |
1370 | preempt_enable(); |
1371 | jump_label_unlock(); |
1372 | |
1373 | p->nmissed = 0; |
1374 | INIT_LIST_HEAD(&p->list); |
1375 | mutex_lock(&kprobe_mutex); |
1376 | |
1377 | jump_label_lock(); /* needed to call jump_label_text_reserved() */ |
1378 | |
1379 | get_online_cpus(); /* For avoiding text_mutex deadlock. */ |
1380 | mutex_lock(&text_mutex); |
1381 | |
1382 | old_p = get_kprobe(p->addr); |
1383 | if (old_p) { |
1384 | /* Since this may unoptimize old_p, locking text_mutex. */ |
1385 | ret = register_aggr_kprobe(old_p, p); |
1386 | goto out; |
1387 | } |
1388 | |
1389 | ret = arch_prepare_kprobe(p); |
1390 | if (ret) |
1391 | goto out; |
1392 | |
1393 | INIT_HLIST_NODE(&p->hlist); |
1394 | hlist_add_head_rcu(&p->hlist, |
1395 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1396 | |
1397 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
1398 | __arm_kprobe(p); |
1399 | |
1400 | /* Try to optimize kprobe */ |
1401 | try_to_optimize_kprobe(p); |
1402 | |
1403 | out: |
1404 | mutex_unlock(&text_mutex); |
1405 | put_online_cpus(); |
1406 | jump_label_unlock(); |
1407 | mutex_unlock(&kprobe_mutex); |
1408 | |
1409 | if (probed_mod) |
1410 | module_put(probed_mod); |
1411 | |
1412 | return ret; |
1413 | |
1414 | cannot_probe: |
1415 | preempt_enable(); |
1416 | jump_label_unlock(); |
1417 | return ret; |
1418 | } |
1419 | EXPORT_SYMBOL_GPL(register_kprobe); |
1420 | |
1421 | /* Check if all probes on the aggrprobe are disabled */ |
1422 | static int __kprobes aggr_kprobe_disabled(struct kprobe *ap) |
1423 | { |
1424 | struct kprobe *kp; |
1425 | |
1426 | list_for_each_entry_rcu(kp, &ap->list, list) |
1427 | if (!kprobe_disabled(kp)) |
1428 | /* |
1429 | * There is an active probe on the list. |
1430 | * We can't disable this ap. |
1431 | */ |
1432 | return 0; |
1433 | |
1434 | return 1; |
1435 | } |
1436 | |
1437 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ |
1438 | static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p) |
1439 | { |
1440 | struct kprobe *orig_p; |
1441 | |
1442 | /* Get an original kprobe for return */ |
1443 | orig_p = __get_valid_kprobe(p); |
1444 | if (unlikely(orig_p == NULL)) |
1445 | return NULL; |
1446 | |
1447 | if (!kprobe_disabled(p)) { |
1448 | /* Disable probe if it is a child probe */ |
1449 | if (p != orig_p) |
1450 | p->flags |= KPROBE_FLAG_DISABLED; |
1451 | |
1452 | /* Try to disarm and disable this/parent probe */ |
1453 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { |
1454 | disarm_kprobe(orig_p); |
1455 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1456 | } |
1457 | } |
1458 | |
1459 | return orig_p; |
1460 | } |
1461 | |
1462 | /* |
1463 | * Unregister a kprobe without a scheduler synchronization. |
1464 | */ |
1465 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) |
1466 | { |
1467 | struct kprobe *ap, *list_p; |
1468 | |
1469 | /* Disable kprobe. This will disarm it if needed. */ |
1470 | ap = __disable_kprobe(p); |
1471 | if (ap == NULL) |
1472 | return -EINVAL; |
1473 | |
1474 | if (ap == p) |
1475 | /* |
1476 | * This probe is an independent(and non-optimized) kprobe |
1477 | * (not an aggrprobe). Remove from the hash list. |
1478 | */ |
1479 | goto disarmed; |
1480 | |
1481 | /* Following process expects this probe is an aggrprobe */ |
1482 | WARN_ON(!kprobe_aggrprobe(ap)); |
1483 | |
1484 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1485 | /* |
1486 | * !disarmed could be happen if the probe is under delayed |
1487 | * unoptimizing. |
1488 | */ |
1489 | goto disarmed; |
1490 | else { |
1491 | /* If disabling probe has special handlers, update aggrprobe */ |
1492 | if (p->break_handler && !kprobe_gone(p)) |
1493 | ap->break_handler = NULL; |
1494 | if (p->post_handler && !kprobe_gone(p)) { |
1495 | list_for_each_entry_rcu(list_p, &ap->list, list) { |
1496 | if ((list_p != p) && (list_p->post_handler)) |
1497 | goto noclean; |
1498 | } |
1499 | ap->post_handler = NULL; |
1500 | } |
1501 | noclean: |
1502 | /* |
1503 | * Remove from the aggrprobe: this path will do nothing in |
1504 | * __unregister_kprobe_bottom(). |
1505 | */ |
1506 | list_del_rcu(&p->list); |
1507 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1508 | /* |
1509 | * Try to optimize this probe again, because post |
1510 | * handler may have been changed. |
1511 | */ |
1512 | optimize_kprobe(ap); |
1513 | } |
1514 | return 0; |
1515 | |
1516 | disarmed: |
1517 | BUG_ON(!kprobe_disarmed(ap)); |
1518 | hlist_del_rcu(&ap->hlist); |
1519 | return 0; |
1520 | } |
1521 | |
1522 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
1523 | { |
1524 | struct kprobe *ap; |
1525 | |
1526 | if (list_empty(&p->list)) |
1527 | /* This is an independent kprobe */ |
1528 | arch_remove_kprobe(p); |
1529 | else if (list_is_singular(&p->list)) { |
1530 | /* This is the last child of an aggrprobe */ |
1531 | ap = list_entry(p->list.next, struct kprobe, list); |
1532 | list_del(&p->list); |
1533 | free_aggr_kprobe(ap); |
1534 | } |
1535 | /* Otherwise, do nothing. */ |
1536 | } |
1537 | |
1538 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
1539 | { |
1540 | int i, ret = 0; |
1541 | |
1542 | if (num <= 0) |
1543 | return -EINVAL; |
1544 | for (i = 0; i < num; i++) { |
1545 | ret = register_kprobe(kps[i]); |
1546 | if (ret < 0) { |
1547 | if (i > 0) |
1548 | unregister_kprobes(kps, i); |
1549 | break; |
1550 | } |
1551 | } |
1552 | return ret; |
1553 | } |
1554 | EXPORT_SYMBOL_GPL(register_kprobes); |
1555 | |
1556 | void __kprobes unregister_kprobe(struct kprobe *p) |
1557 | { |
1558 | unregister_kprobes(&p, 1); |
1559 | } |
1560 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
1561 | |
1562 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
1563 | { |
1564 | int i; |
1565 | |
1566 | if (num <= 0) |
1567 | return; |
1568 | mutex_lock(&kprobe_mutex); |
1569 | for (i = 0; i < num; i++) |
1570 | if (__unregister_kprobe_top(kps[i]) < 0) |
1571 | kps[i]->addr = NULL; |
1572 | mutex_unlock(&kprobe_mutex); |
1573 | |
1574 | synchronize_sched(); |
1575 | for (i = 0; i < num; i++) |
1576 | if (kps[i]->addr) |
1577 | __unregister_kprobe_bottom(kps[i]); |
1578 | } |
1579 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1580 | |
1581 | static struct notifier_block kprobe_exceptions_nb = { |
1582 | .notifier_call = kprobe_exceptions_notify, |
1583 | .priority = 0x7fffffff /* we need to be notified first */ |
1584 | }; |
1585 | |
1586 | unsigned long __weak arch_deref_entry_point(void *entry) |
1587 | { |
1588 | return (unsigned long)entry; |
1589 | } |
1590 | |
1591 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1592 | { |
1593 | struct jprobe *jp; |
1594 | int ret = 0, i; |
1595 | |
1596 | if (num <= 0) |
1597 | return -EINVAL; |
1598 | for (i = 0; i < num; i++) { |
1599 | unsigned long addr, offset; |
1600 | jp = jps[i]; |
1601 | addr = arch_deref_entry_point(jp->entry); |
1602 | |
1603 | /* Verify probepoint is a function entry point */ |
1604 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && |
1605 | offset == 0) { |
1606 | jp->kp.pre_handler = setjmp_pre_handler; |
1607 | jp->kp.break_handler = longjmp_break_handler; |
1608 | ret = register_kprobe(&jp->kp); |
1609 | } else |
1610 | ret = -EINVAL; |
1611 | |
1612 | if (ret < 0) { |
1613 | if (i > 0) |
1614 | unregister_jprobes(jps, i); |
1615 | break; |
1616 | } |
1617 | } |
1618 | return ret; |
1619 | } |
1620 | EXPORT_SYMBOL_GPL(register_jprobes); |
1621 | |
1622 | int __kprobes register_jprobe(struct jprobe *jp) |
1623 | { |
1624 | return register_jprobes(&jp, 1); |
1625 | } |
1626 | EXPORT_SYMBOL_GPL(register_jprobe); |
1627 | |
1628 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1629 | { |
1630 | unregister_jprobes(&jp, 1); |
1631 | } |
1632 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
1633 | |
1634 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
1635 | { |
1636 | int i; |
1637 | |
1638 | if (num <= 0) |
1639 | return; |
1640 | mutex_lock(&kprobe_mutex); |
1641 | for (i = 0; i < num; i++) |
1642 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) |
1643 | jps[i]->kp.addr = NULL; |
1644 | mutex_unlock(&kprobe_mutex); |
1645 | |
1646 | synchronize_sched(); |
1647 | for (i = 0; i < num; i++) { |
1648 | if (jps[i]->kp.addr) |
1649 | __unregister_kprobe_bottom(&jps[i]->kp); |
1650 | } |
1651 | } |
1652 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1653 | |
1654 | #ifdef CONFIG_KRETPROBES |
1655 | /* |
1656 | * This kprobe pre_handler is registered with every kretprobe. When probe |
1657 | * hits it will set up the return probe. |
1658 | */ |
1659 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1660 | struct pt_regs *regs) |
1661 | { |
1662 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
1663 | unsigned long hash, flags = 0; |
1664 | struct kretprobe_instance *ri; |
1665 | |
1666 | /*TODO: consider to only swap the RA after the last pre_handler fired */ |
1667 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
1668 | raw_spin_lock_irqsave(&rp->lock, flags); |
1669 | if (!hlist_empty(&rp->free_instances)) { |
1670 | ri = hlist_entry(rp->free_instances.first, |
1671 | struct kretprobe_instance, hlist); |
1672 | hlist_del(&ri->hlist); |
1673 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
1674 | |
1675 | ri->rp = rp; |
1676 | ri->task = current; |
1677 | |
1678 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1679 | raw_spin_lock_irqsave(&rp->lock, flags); |
1680 | hlist_add_head(&ri->hlist, &rp->free_instances); |
1681 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
1682 | return 0; |
1683 | } |
1684 | |
1685 | arch_prepare_kretprobe(ri, regs); |
1686 | |
1687 | /* XXX(hch): why is there no hlist_move_head? */ |
1688 | INIT_HLIST_NODE(&ri->hlist); |
1689 | kretprobe_table_lock(hash, &flags); |
1690 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); |
1691 | kretprobe_table_unlock(hash, &flags); |
1692 | } else { |
1693 | rp->nmissed++; |
1694 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
1695 | } |
1696 | return 0; |
1697 | } |
1698 | |
1699 | int __kprobes register_kretprobe(struct kretprobe *rp) |
1700 | { |
1701 | int ret = 0; |
1702 | struct kretprobe_instance *inst; |
1703 | int i; |
1704 | void *addr; |
1705 | |
1706 | if (kretprobe_blacklist_size) { |
1707 | addr = kprobe_addr(&rp->kp); |
1708 | if (IS_ERR(addr)) |
1709 | return PTR_ERR(addr); |
1710 | |
1711 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1712 | if (kretprobe_blacklist[i].addr == addr) |
1713 | return -EINVAL; |
1714 | } |
1715 | } |
1716 | |
1717 | rp->kp.pre_handler = pre_handler_kretprobe; |
1718 | rp->kp.post_handler = NULL; |
1719 | rp->kp.fault_handler = NULL; |
1720 | rp->kp.break_handler = NULL; |
1721 | |
1722 | /* Pre-allocate memory for max kretprobe instances */ |
1723 | if (rp->maxactive <= 0) { |
1724 | #ifdef CONFIG_PREEMPT |
1725 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
1726 | #else |
1727 | rp->maxactive = num_possible_cpus(); |
1728 | #endif |
1729 | } |
1730 | raw_spin_lock_init(&rp->lock); |
1731 | INIT_HLIST_HEAD(&rp->free_instances); |
1732 | for (i = 0; i < rp->maxactive; i++) { |
1733 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1734 | rp->data_size, GFP_KERNEL); |
1735 | if (inst == NULL) { |
1736 | free_rp_inst(rp); |
1737 | return -ENOMEM; |
1738 | } |
1739 | INIT_HLIST_NODE(&inst->hlist); |
1740 | hlist_add_head(&inst->hlist, &rp->free_instances); |
1741 | } |
1742 | |
1743 | rp->nmissed = 0; |
1744 | /* Establish function entry probe point */ |
1745 | ret = register_kprobe(&rp->kp); |
1746 | if (ret != 0) |
1747 | free_rp_inst(rp); |
1748 | return ret; |
1749 | } |
1750 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1751 | |
1752 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
1753 | { |
1754 | int ret = 0, i; |
1755 | |
1756 | if (num <= 0) |
1757 | return -EINVAL; |
1758 | for (i = 0; i < num; i++) { |
1759 | ret = register_kretprobe(rps[i]); |
1760 | if (ret < 0) { |
1761 | if (i > 0) |
1762 | unregister_kretprobes(rps, i); |
1763 | break; |
1764 | } |
1765 | } |
1766 | return ret; |
1767 | } |
1768 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1769 | |
1770 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1771 | { |
1772 | unregister_kretprobes(&rp, 1); |
1773 | } |
1774 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1775 | |
1776 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1777 | { |
1778 | int i; |
1779 | |
1780 | if (num <= 0) |
1781 | return; |
1782 | mutex_lock(&kprobe_mutex); |
1783 | for (i = 0; i < num; i++) |
1784 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
1785 | rps[i]->kp.addr = NULL; |
1786 | mutex_unlock(&kprobe_mutex); |
1787 | |
1788 | synchronize_sched(); |
1789 | for (i = 0; i < num; i++) { |
1790 | if (rps[i]->kp.addr) { |
1791 | __unregister_kprobe_bottom(&rps[i]->kp); |
1792 | cleanup_rp_inst(rps[i]); |
1793 | } |
1794 | } |
1795 | } |
1796 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1797 | |
1798 | #else /* CONFIG_KRETPROBES */ |
1799 | int __kprobes register_kretprobe(struct kretprobe *rp) |
1800 | { |
1801 | return -ENOSYS; |
1802 | } |
1803 | EXPORT_SYMBOL_GPL(register_kretprobe); |
1804 | |
1805 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
1806 | { |
1807 | return -ENOSYS; |
1808 | } |
1809 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1810 | |
1811 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1812 | { |
1813 | } |
1814 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
1815 | |
1816 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1817 | { |
1818 | } |
1819 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
1820 | |
1821 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1822 | struct pt_regs *regs) |
1823 | { |
1824 | return 0; |
1825 | } |
1826 | |
1827 | #endif /* CONFIG_KRETPROBES */ |
1828 | |
1829 | /* Set the kprobe gone and remove its instruction buffer. */ |
1830 | static void __kprobes kill_kprobe(struct kprobe *p) |
1831 | { |
1832 | struct kprobe *kp; |
1833 | |
1834 | p->flags |= KPROBE_FLAG_GONE; |
1835 | if (kprobe_aggrprobe(p)) { |
1836 | /* |
1837 | * If this is an aggr_kprobe, we have to list all the |
1838 | * chained probes and mark them GONE. |
1839 | */ |
1840 | list_for_each_entry_rcu(kp, &p->list, list) |
1841 | kp->flags |= KPROBE_FLAG_GONE; |
1842 | p->post_handler = NULL; |
1843 | p->break_handler = NULL; |
1844 | kill_optimized_kprobe(p); |
1845 | } |
1846 | /* |
1847 | * Here, we can remove insn_slot safely, because no thread calls |
1848 | * the original probed function (which will be freed soon) any more. |
1849 | */ |
1850 | arch_remove_kprobe(p); |
1851 | } |
1852 | |
1853 | /* Disable one kprobe */ |
1854 | int __kprobes disable_kprobe(struct kprobe *kp) |
1855 | { |
1856 | int ret = 0; |
1857 | |
1858 | mutex_lock(&kprobe_mutex); |
1859 | |
1860 | /* Disable this kprobe */ |
1861 | if (__disable_kprobe(kp) == NULL) |
1862 | ret = -EINVAL; |
1863 | |
1864 | mutex_unlock(&kprobe_mutex); |
1865 | return ret; |
1866 | } |
1867 | EXPORT_SYMBOL_GPL(disable_kprobe); |
1868 | |
1869 | /* Enable one kprobe */ |
1870 | int __kprobes enable_kprobe(struct kprobe *kp) |
1871 | { |
1872 | int ret = 0; |
1873 | struct kprobe *p; |
1874 | |
1875 | mutex_lock(&kprobe_mutex); |
1876 | |
1877 | /* Check whether specified probe is valid. */ |
1878 | p = __get_valid_kprobe(kp); |
1879 | if (unlikely(p == NULL)) { |
1880 | ret = -EINVAL; |
1881 | goto out; |
1882 | } |
1883 | |
1884 | if (kprobe_gone(kp)) { |
1885 | /* This kprobe has gone, we couldn't enable it. */ |
1886 | ret = -EINVAL; |
1887 | goto out; |
1888 | } |
1889 | |
1890 | if (p != kp) |
1891 | kp->flags &= ~KPROBE_FLAG_DISABLED; |
1892 | |
1893 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { |
1894 | p->flags &= ~KPROBE_FLAG_DISABLED; |
1895 | arm_kprobe(p); |
1896 | } |
1897 | out: |
1898 | mutex_unlock(&kprobe_mutex); |
1899 | return ret; |
1900 | } |
1901 | EXPORT_SYMBOL_GPL(enable_kprobe); |
1902 | |
1903 | void __kprobes dump_kprobe(struct kprobe *kp) |
1904 | { |
1905 | printk(KERN_WARNING "Dumping kprobe:\n"); |
1906 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", |
1907 | kp->symbol_name, kp->addr, kp->offset); |
1908 | } |
1909 | |
1910 | /* Module notifier call back, checking kprobes on the module */ |
1911 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, |
1912 | unsigned long val, void *data) |
1913 | { |
1914 | struct module *mod = data; |
1915 | struct hlist_head *head; |
1916 | struct hlist_node *node; |
1917 | struct kprobe *p; |
1918 | unsigned int i; |
1919 | int checkcore = (val == MODULE_STATE_GOING); |
1920 | |
1921 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
1922 | return NOTIFY_DONE; |
1923 | |
1924 | /* |
1925 | * When MODULE_STATE_GOING was notified, both of module .text and |
1926 | * .init.text sections would be freed. When MODULE_STATE_LIVE was |
1927 | * notified, only .init.text section would be freed. We need to |
1928 | * disable kprobes which have been inserted in the sections. |
1929 | */ |
1930 | mutex_lock(&kprobe_mutex); |
1931 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1932 | head = &kprobe_table[i]; |
1933 | hlist_for_each_entry_rcu(p, node, head, hlist) |
1934 | if (within_module_init((unsigned long)p->addr, mod) || |
1935 | (checkcore && |
1936 | within_module_core((unsigned long)p->addr, mod))) { |
1937 | /* |
1938 | * The vaddr this probe is installed will soon |
1939 | * be vfreed buy not synced to disk. Hence, |
1940 | * disarming the breakpoint isn't needed. |
1941 | */ |
1942 | kill_kprobe(p); |
1943 | } |
1944 | } |
1945 | mutex_unlock(&kprobe_mutex); |
1946 | return NOTIFY_DONE; |
1947 | } |
1948 | |
1949 | static struct notifier_block kprobe_module_nb = { |
1950 | .notifier_call = kprobes_module_callback, |
1951 | .priority = 0 |
1952 | }; |
1953 | |
1954 | static int __init init_kprobes(void) |
1955 | { |
1956 | int i, err = 0; |
1957 | unsigned long offset = 0, size = 0; |
1958 | char *modname, namebuf[128]; |
1959 | const char *symbol_name; |
1960 | void *addr; |
1961 | struct kprobe_blackpoint *kb; |
1962 | |
1963 | /* FIXME allocate the probe table, currently defined statically */ |
1964 | /* initialize all list heads */ |
1965 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1966 | INIT_HLIST_HEAD(&kprobe_table[i]); |
1967 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
1968 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
1969 | } |
1970 | |
1971 | /* |
1972 | * Lookup and populate the kprobe_blacklist. |
1973 | * |
1974 | * Unlike the kretprobe blacklist, we'll need to determine |
1975 | * the range of addresses that belong to the said functions, |
1976 | * since a kprobe need not necessarily be at the beginning |
1977 | * of a function. |
1978 | */ |
1979 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { |
1980 | kprobe_lookup_name(kb->name, addr); |
1981 | if (!addr) |
1982 | continue; |
1983 | |
1984 | kb->start_addr = (unsigned long)addr; |
1985 | symbol_name = kallsyms_lookup(kb->start_addr, |
1986 | &size, &offset, &modname, namebuf); |
1987 | if (!symbol_name) |
1988 | kb->range = 0; |
1989 | else |
1990 | kb->range = size; |
1991 | } |
1992 | |
1993 | if (kretprobe_blacklist_size) { |
1994 | /* lookup the function address from its name */ |
1995 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
1996 | kprobe_lookup_name(kretprobe_blacklist[i].name, |
1997 | kretprobe_blacklist[i].addr); |
1998 | if (!kretprobe_blacklist[i].addr) |
1999 | printk("kretprobe: lookup failed: %s\n", |
2000 | kretprobe_blacklist[i].name); |
2001 | } |
2002 | } |
2003 | |
2004 | #if defined(CONFIG_OPTPROBES) |
2005 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
2006 | /* Init kprobe_optinsn_slots */ |
2007 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
2008 | #endif |
2009 | /* By default, kprobes can be optimized */ |
2010 | kprobes_allow_optimization = true; |
2011 | #endif |
2012 | |
2013 | /* By default, kprobes are armed */ |
2014 | kprobes_all_disarmed = false; |
2015 | |
2016 | err = arch_init_kprobes(); |
2017 | if (!err) |
2018 | err = register_die_notifier(&kprobe_exceptions_nb); |
2019 | if (!err) |
2020 | err = register_module_notifier(&kprobe_module_nb); |
2021 | |
2022 | kprobes_initialized = (err == 0); |
2023 | |
2024 | if (!err) |
2025 | init_test_probes(); |
2026 | return err; |
2027 | } |
2028 | |
2029 | #ifdef CONFIG_DEBUG_FS |
2030 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, |
2031 | const char *sym, int offset, char *modname, struct kprobe *pp) |
2032 | { |
2033 | char *kprobe_type; |
2034 | |
2035 | if (p->pre_handler == pre_handler_kretprobe) |
2036 | kprobe_type = "r"; |
2037 | else if (p->pre_handler == setjmp_pre_handler) |
2038 | kprobe_type = "j"; |
2039 | else |
2040 | kprobe_type = "k"; |
2041 | |
2042 | if (sym) |
2043 | seq_printf(pi, "%p %s %s+0x%x %s ", |
2044 | p->addr, kprobe_type, sym, offset, |
2045 | (modname ? modname : " ")); |
2046 | else |
2047 | seq_printf(pi, "%p %s %p ", |
2048 | p->addr, kprobe_type, p->addr); |
2049 | |
2050 | if (!pp) |
2051 | pp = p; |
2052 | seq_printf(pi, "%s%s%s\n", |
2053 | (kprobe_gone(p) ? "[GONE]" : ""), |
2054 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), |
2055 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : "")); |
2056 | } |
2057 | |
2058 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
2059 | { |
2060 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; |
2061 | } |
2062 | |
2063 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
2064 | { |
2065 | (*pos)++; |
2066 | if (*pos >= KPROBE_TABLE_SIZE) |
2067 | return NULL; |
2068 | return pos; |
2069 | } |
2070 | |
2071 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) |
2072 | { |
2073 | /* Nothing to do */ |
2074 | } |
2075 | |
2076 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) |
2077 | { |
2078 | struct hlist_head *head; |
2079 | struct hlist_node *node; |
2080 | struct kprobe *p, *kp; |
2081 | const char *sym = NULL; |
2082 | unsigned int i = *(loff_t *) v; |
2083 | unsigned long offset = 0; |
2084 | char *modname, namebuf[128]; |
2085 | |
2086 | head = &kprobe_table[i]; |
2087 | preempt_disable(); |
2088 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
2089 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
2090 | &offset, &modname, namebuf); |
2091 | if (kprobe_aggrprobe(p)) { |
2092 | list_for_each_entry_rcu(kp, &p->list, list) |
2093 | report_probe(pi, kp, sym, offset, modname, p); |
2094 | } else |
2095 | report_probe(pi, p, sym, offset, modname, NULL); |
2096 | } |
2097 | preempt_enable(); |
2098 | return 0; |
2099 | } |
2100 | |
2101 | static const struct seq_operations kprobes_seq_ops = { |
2102 | .start = kprobe_seq_start, |
2103 | .next = kprobe_seq_next, |
2104 | .stop = kprobe_seq_stop, |
2105 | .show = show_kprobe_addr |
2106 | }; |
2107 | |
2108 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) |
2109 | { |
2110 | return seq_open(filp, &kprobes_seq_ops); |
2111 | } |
2112 | |
2113 | static const struct file_operations debugfs_kprobes_operations = { |
2114 | .open = kprobes_open, |
2115 | .read = seq_read, |
2116 | .llseek = seq_lseek, |
2117 | .release = seq_release, |
2118 | }; |
2119 | |
2120 | static void __kprobes arm_all_kprobes(void) |
2121 | { |
2122 | struct hlist_head *head; |
2123 | struct hlist_node *node; |
2124 | struct kprobe *p; |
2125 | unsigned int i; |
2126 | |
2127 | mutex_lock(&kprobe_mutex); |
2128 | |
2129 | /* If kprobes are armed, just return */ |
2130 | if (!kprobes_all_disarmed) |
2131 | goto already_enabled; |
2132 | |
2133 | /* Arming kprobes doesn't optimize kprobe itself */ |
2134 | mutex_lock(&text_mutex); |
2135 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2136 | head = &kprobe_table[i]; |
2137 | hlist_for_each_entry_rcu(p, node, head, hlist) |
2138 | if (!kprobe_disabled(p)) |
2139 | __arm_kprobe(p); |
2140 | } |
2141 | mutex_unlock(&text_mutex); |
2142 | |
2143 | kprobes_all_disarmed = false; |
2144 | printk(KERN_INFO "Kprobes globally enabled\n"); |
2145 | |
2146 | already_enabled: |
2147 | mutex_unlock(&kprobe_mutex); |
2148 | return; |
2149 | } |
2150 | |
2151 | static void __kprobes disarm_all_kprobes(void) |
2152 | { |
2153 | struct hlist_head *head; |
2154 | struct hlist_node *node; |
2155 | struct kprobe *p; |
2156 | unsigned int i; |
2157 | |
2158 | mutex_lock(&kprobe_mutex); |
2159 | |
2160 | /* If kprobes are already disarmed, just return */ |
2161 | if (kprobes_all_disarmed) { |
2162 | mutex_unlock(&kprobe_mutex); |
2163 | return; |
2164 | } |
2165 | |
2166 | kprobes_all_disarmed = true; |
2167 | printk(KERN_INFO "Kprobes globally disabled\n"); |
2168 | |
2169 | mutex_lock(&text_mutex); |
2170 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2171 | head = &kprobe_table[i]; |
2172 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
2173 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
2174 | __disarm_kprobe(p, false); |
2175 | } |
2176 | } |
2177 | mutex_unlock(&text_mutex); |
2178 | mutex_unlock(&kprobe_mutex); |
2179 | |
2180 | /* Wait for disarming all kprobes by optimizer */ |
2181 | wait_for_kprobe_optimizer(); |
2182 | } |
2183 | |
2184 | /* |
2185 | * XXX: The debugfs bool file interface doesn't allow for callbacks |
2186 | * when the bool state is switched. We can reuse that facility when |
2187 | * available |
2188 | */ |
2189 | static ssize_t read_enabled_file_bool(struct file *file, |
2190 | char __user *user_buf, size_t count, loff_t *ppos) |
2191 | { |
2192 | char buf[3]; |
2193 | |
2194 | if (!kprobes_all_disarmed) |
2195 | buf[0] = '1'; |
2196 | else |
2197 | buf[0] = '0'; |
2198 | buf[1] = '\n'; |
2199 | buf[2] = 0x00; |
2200 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); |
2201 | } |
2202 | |
2203 | static ssize_t write_enabled_file_bool(struct file *file, |
2204 | const char __user *user_buf, size_t count, loff_t *ppos) |
2205 | { |
2206 | char buf[32]; |
2207 | size_t buf_size; |
2208 | |
2209 | buf_size = min(count, (sizeof(buf)-1)); |
2210 | if (copy_from_user(buf, user_buf, buf_size)) |
2211 | return -EFAULT; |
2212 | |
2213 | switch (buf[0]) { |
2214 | case 'y': |
2215 | case 'Y': |
2216 | case '1': |
2217 | arm_all_kprobes(); |
2218 | break; |
2219 | case 'n': |
2220 | case 'N': |
2221 | case '0': |
2222 | disarm_all_kprobes(); |
2223 | break; |
2224 | } |
2225 | |
2226 | return count; |
2227 | } |
2228 | |
2229 | static const struct file_operations fops_kp = { |
2230 | .read = read_enabled_file_bool, |
2231 | .write = write_enabled_file_bool, |
2232 | .llseek = default_llseek, |
2233 | }; |
2234 | |
2235 | static int __kprobes debugfs_kprobe_init(void) |
2236 | { |
2237 | struct dentry *dir, *file; |
2238 | unsigned int value = 1; |
2239 | |
2240 | dir = debugfs_create_dir("kprobes", NULL); |
2241 | if (!dir) |
2242 | return -ENOMEM; |
2243 | |
2244 | file = debugfs_create_file("list", 0444, dir, NULL, |
2245 | &debugfs_kprobes_operations); |
2246 | if (!file) { |
2247 | debugfs_remove(dir); |
2248 | return -ENOMEM; |
2249 | } |
2250 | |
2251 | file = debugfs_create_file("enabled", 0600, dir, |
2252 | &value, &fops_kp); |
2253 | if (!file) { |
2254 | debugfs_remove(dir); |
2255 | return -ENOMEM; |
2256 | } |
2257 | |
2258 | return 0; |
2259 | } |
2260 | |
2261 | late_initcall(debugfs_kprobe_init); |
2262 | #endif /* CONFIG_DEBUG_FS */ |
2263 | |
2264 | module_init(init_kprobes); |
2265 | |
2266 | /* defined in arch/.../kernel/kprobes.c */ |
2267 | EXPORT_SYMBOL_GPL(jprobe_return); |
2268 |
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