Commit | Line | Data |
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1da177e4 LT |
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. | |
b94cce92 HN |
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. | |
1da177e4 LT |
33 | */ |
34 | #include <linux/kprobes.h> | |
1da177e4 LT |
35 | #include <linux/hash.h> |
36 | #include <linux/init.h> | |
4e57b681 | 37 | #include <linux/slab.h> |
e3869792 | 38 | #include <linux/stddef.h> |
9984de1a | 39 | #include <linux/export.h> |
9ec4b1f3 | 40 | #include <linux/moduleloader.h> |
3a872d89 | 41 | #include <linux/kallsyms.h> |
b4c6c34a | 42 | #include <linux/freezer.h> |
346fd59b SD |
43 | #include <linux/seq_file.h> |
44 | #include <linux/debugfs.h> | |
b2be84df | 45 | #include <linux/sysctl.h> |
1eeb66a1 | 46 | #include <linux/kdebug.h> |
4460fdad | 47 | #include <linux/memory.h> |
4554dbcb | 48 | #include <linux/ftrace.h> |
afd66255 | 49 | #include <linux/cpu.h> |
bf5438fc | 50 | #include <linux/jump_label.h> |
bf8f6e5b | 51 | |
bfd45be0 | 52 | #include <asm/sections.h> |
1da177e4 LT |
53 | #include <asm/cacheflush.h> |
54 | #include <asm/errno.h> | |
7c0f6ba6 | 55 | #include <linux/uaccess.h> |
1da177e4 LT |
56 | |
57 | #define KPROBE_HASH_BITS 6 | |
58 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
59 | ||
3a872d89 | 60 | |
ef53d9c5 | 61 | static int kprobes_initialized; |
1da177e4 | 62 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 63 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 64 | |
bf8f6e5b | 65 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 66 | static bool kprobes_all_disarmed; |
bf8f6e5b | 67 | |
43948f50 MH |
68 | /* This protects kprobe_table and optimizing_list */ |
69 | static DEFINE_MUTEX(kprobe_mutex); | |
e6584523 | 70 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 71 | static struct { |
ec484608 | 72 | raw_spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
73 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
74 | ||
49e0b465 NR |
75 | kprobe_opcode_t * __weak kprobe_lookup_name(const char *name) |
76 | { | |
77 | return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); | |
78 | } | |
79 | ||
ec484608 | 80 | static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
ef53d9c5 S |
81 | { |
82 | return &(kretprobe_table_locks[hash].lock); | |
83 | } | |
1da177e4 | 84 | |
376e2424 MH |
85 | /* Blacklist -- list of struct kprobe_blacklist_entry */ |
86 | static LIST_HEAD(kprobe_blacklist); | |
3d8d996e | 87 | |
2d14e39d | 88 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
89 | /* |
90 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
91 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
92 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
93 | * is a recipe for disaster | |
94 | */ | |
9ec4b1f3 | 95 | struct kprobe_insn_page { |
c5cb5a2d | 96 | struct list_head list; |
9ec4b1f3 | 97 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
af96397d | 98 | struct kprobe_insn_cache *cache; |
9ec4b1f3 | 99 | int nused; |
b4c6c34a | 100 | int ngarbage; |
4610ee1d | 101 | char slot_used[]; |
9ec4b1f3 AM |
102 | }; |
103 | ||
4610ee1d MH |
104 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
105 | (offsetof(struct kprobe_insn_page, slot_used) + \ | |
106 | (sizeof(char) * (slots))) | |
107 | ||
4610ee1d MH |
108 | static int slots_per_page(struct kprobe_insn_cache *c) |
109 | { | |
110 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
111 | } | |
112 | ||
ab40c5c6 MH |
113 | enum kprobe_slot_state { |
114 | SLOT_CLEAN = 0, | |
115 | SLOT_DIRTY = 1, | |
116 | SLOT_USED = 2, | |
117 | }; | |
118 | ||
af96397d HC |
119 | static void *alloc_insn_page(void) |
120 | { | |
121 | return module_alloc(PAGE_SIZE); | |
122 | } | |
123 | ||
124 | static void free_insn_page(void *page) | |
125 | { | |
be1f221c | 126 | module_memfree(page); |
af96397d HC |
127 | } |
128 | ||
c802d64a HC |
129 | struct kprobe_insn_cache kprobe_insn_slots = { |
130 | .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), | |
af96397d HC |
131 | .alloc = alloc_insn_page, |
132 | .free = free_insn_page, | |
4610ee1d MH |
133 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
134 | .insn_size = MAX_INSN_SIZE, | |
135 | .nr_garbage = 0, | |
136 | }; | |
55479f64 | 137 | static int collect_garbage_slots(struct kprobe_insn_cache *c); |
b4c6c34a | 138 | |
9ec4b1f3 | 139 | /** |
12941560 | 140 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
141 | * We allocate an executable page if there's no room on existing ones. |
142 | */ | |
55479f64 | 143 | kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
144 | { |
145 | struct kprobe_insn_page *kip; | |
c802d64a | 146 | kprobe_opcode_t *slot = NULL; |
9ec4b1f3 | 147 | |
5b485629 | 148 | /* Since the slot array is not protected by rcu, we need a mutex */ |
c802d64a | 149 | mutex_lock(&c->mutex); |
6f716acd | 150 | retry: |
5b485629 MH |
151 | rcu_read_lock(); |
152 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
4610ee1d | 153 | if (kip->nused < slots_per_page(c)) { |
9ec4b1f3 | 154 | int i; |
4610ee1d | 155 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
156 | if (kip->slot_used[i] == SLOT_CLEAN) { |
157 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 158 | kip->nused++; |
c802d64a | 159 | slot = kip->insns + (i * c->insn_size); |
5b485629 | 160 | rcu_read_unlock(); |
c802d64a | 161 | goto out; |
9ec4b1f3 AM |
162 | } |
163 | } | |
4610ee1d MH |
164 | /* kip->nused is broken. Fix it. */ |
165 | kip->nused = slots_per_page(c); | |
166 | WARN_ON(1); | |
9ec4b1f3 AM |
167 | } |
168 | } | |
5b485629 | 169 | rcu_read_unlock(); |
9ec4b1f3 | 170 | |
b4c6c34a | 171 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 172 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 173 | goto retry; |
4610ee1d MH |
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); | |
6f716acd | 177 | if (!kip) |
c802d64a | 178 | goto out; |
9ec4b1f3 AM |
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 | */ | |
af96397d | 185 | kip->insns = c->alloc(); |
9ec4b1f3 AM |
186 | if (!kip->insns) { |
187 | kfree(kip); | |
c802d64a | 188 | goto out; |
9ec4b1f3 | 189 | } |
c5cb5a2d | 190 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 191 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 192 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 193 | kip->nused = 1; |
b4c6c34a | 194 | kip->ngarbage = 0; |
af96397d | 195 | kip->cache = c; |
5b485629 | 196 | list_add_rcu(&kip->list, &c->pages); |
c802d64a HC |
197 | slot = kip->insns; |
198 | out: | |
199 | mutex_unlock(&c->mutex); | |
200 | return slot; | |
12941560 MH |
201 | } |
202 | ||
b4c6c34a | 203 | /* Return 1 if all garbages are collected, otherwise 0. */ |
55479f64 | 204 | static int collect_one_slot(struct kprobe_insn_page *kip, int idx) |
b4c6c34a | 205 | { |
ab40c5c6 | 206 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
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 | */ | |
4610ee1d | 215 | if (!list_is_singular(&kip->list)) { |
5b485629 MH |
216 | list_del_rcu(&kip->list); |
217 | synchronize_rcu(); | |
af96397d | 218 | kip->cache->free(kip->insns); |
b4c6c34a MH |
219 | kfree(kip); |
220 | } | |
221 | return 1; | |
222 | } | |
223 | return 0; | |
224 | } | |
225 | ||
55479f64 | 226 | static int collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 227 | { |
c5cb5a2d | 228 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 229 | |
615d0ebb MH |
230 | /* Ensure no-one is interrupted on the garbages */ |
231 | synchronize_sched(); | |
b4c6c34a | 232 | |
4610ee1d | 233 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 234 | int i; |
b4c6c34a MH |
235 | if (kip->ngarbage == 0) |
236 | continue; | |
237 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 238 | for (i = 0; i < slots_per_page(c); i++) { |
5b485629 | 239 | if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i)) |
b4c6c34a MH |
240 | break; |
241 | } | |
242 | } | |
4610ee1d | 243 | c->nr_garbage = 0; |
b4c6c34a MH |
244 | return 0; |
245 | } | |
246 | ||
55479f64 MH |
247 | void __free_insn_slot(struct kprobe_insn_cache *c, |
248 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
249 | { |
250 | struct kprobe_insn_page *kip; | |
5b485629 | 251 | long idx; |
9ec4b1f3 | 252 | |
c802d64a | 253 | mutex_lock(&c->mutex); |
5b485629 MH |
254 | rcu_read_lock(); |
255 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
256 | idx = ((long)slot - (long)kip->insns) / | |
257 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
258 | if (idx >= 0 && idx < slots_per_page(c)) | |
c802d64a | 259 | goto out; |
9ec4b1f3 | 260 | } |
5b485629 | 261 | /* Could not find this slot. */ |
4610ee1d | 262 | WARN_ON(1); |
5b485629 | 263 | kip = NULL; |
c802d64a | 264 | out: |
5b485629 MH |
265 | rcu_read_unlock(); |
266 | /* Mark and sweep: this may sleep */ | |
267 | if (kip) { | |
268 | /* Check double free */ | |
269 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
270 | if (dirty) { | |
271 | kip->slot_used[idx] = SLOT_DIRTY; | |
272 | kip->ngarbage++; | |
273 | if (++c->nr_garbage > slots_per_page(c)) | |
274 | collect_garbage_slots(c); | |
275 | } else { | |
276 | collect_one_slot(kip, idx); | |
277 | } | |
278 | } | |
c802d64a | 279 | mutex_unlock(&c->mutex); |
4610ee1d | 280 | } |
6f716acd | 281 | |
5b485629 MH |
282 | /* |
283 | * Check given address is on the page of kprobe instruction slots. | |
284 | * This will be used for checking whether the address on a stack | |
285 | * is on a text area or not. | |
286 | */ | |
287 | bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr) | |
288 | { | |
289 | struct kprobe_insn_page *kip; | |
290 | bool ret = false; | |
291 | ||
292 | rcu_read_lock(); | |
293 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
294 | if (addr >= (unsigned long)kip->insns && | |
295 | addr < (unsigned long)kip->insns + PAGE_SIZE) { | |
296 | ret = true; | |
297 | break; | |
298 | } | |
299 | } | |
300 | rcu_read_unlock(); | |
301 | ||
302 | return ret; | |
303 | } | |
304 | ||
afd66255 MH |
305 | #ifdef CONFIG_OPTPROBES |
306 | /* For optimized_kprobe buffer */ | |
c802d64a HC |
307 | struct kprobe_insn_cache kprobe_optinsn_slots = { |
308 | .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), | |
af96397d HC |
309 | .alloc = alloc_insn_page, |
310 | .free = free_insn_page, | |
afd66255 MH |
311 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
312 | /* .insn_size is initialized later */ | |
313 | .nr_garbage = 0, | |
314 | }; | |
afd66255 | 315 | #endif |
2d14e39d | 316 | #endif |
9ec4b1f3 | 317 | |
e6584523 AM |
318 | /* We have preemption disabled.. so it is safe to use __ versions */ |
319 | static inline void set_kprobe_instance(struct kprobe *kp) | |
320 | { | |
b76834bc | 321 | __this_cpu_write(kprobe_instance, kp); |
e6584523 AM |
322 | } |
323 | ||
324 | static inline void reset_kprobe_instance(void) | |
325 | { | |
b76834bc | 326 | __this_cpu_write(kprobe_instance, NULL); |
e6584523 AM |
327 | } |
328 | ||
3516a460 AM |
329 | /* |
330 | * This routine is called either: | |
49a2a1b8 | 331 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 332 | * OR |
d217d545 | 333 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 334 | */ |
820aede0 | 335 | struct kprobe *get_kprobe(void *addr) |
1da177e4 LT |
336 | { |
337 | struct hlist_head *head; | |
3516a460 | 338 | struct kprobe *p; |
1da177e4 LT |
339 | |
340 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
b67bfe0d | 341 | hlist_for_each_entry_rcu(p, head, hlist) { |
1da177e4 LT |
342 | if (p->addr == addr) |
343 | return p; | |
344 | } | |
afd66255 | 345 | |
1da177e4 LT |
346 | return NULL; |
347 | } | |
820aede0 | 348 | NOKPROBE_SYMBOL(get_kprobe); |
1da177e4 | 349 | |
820aede0 | 350 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
afd66255 MH |
351 | |
352 | /* Return true if the kprobe is an aggregator */ | |
353 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
354 | { | |
355 | return p->pre_handler == aggr_pre_handler; | |
356 | } | |
357 | ||
6274de49 MH |
358 | /* Return true(!0) if the kprobe is unused */ |
359 | static inline int kprobe_unused(struct kprobe *p) | |
360 | { | |
361 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && | |
362 | list_empty(&p->list); | |
363 | } | |
364 | ||
afd66255 MH |
365 | /* |
366 | * Keep all fields in the kprobe consistent | |
367 | */ | |
6d8e40a8 | 368 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 369 | { |
6d8e40a8 MH |
370 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
371 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
372 | } |
373 | ||
374 | #ifdef CONFIG_OPTPROBES | |
b2be84df MH |
375 | /* NOTE: change this value only with kprobe_mutex held */ |
376 | static bool kprobes_allow_optimization; | |
377 | ||
afd66255 MH |
378 | /* |
379 | * Call all pre_handler on the list, but ignores its return value. | |
380 | * This must be called from arch-dep optimized caller. | |
381 | */ | |
820aede0 | 382 | void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
afd66255 MH |
383 | { |
384 | struct kprobe *kp; | |
385 | ||
386 | list_for_each_entry_rcu(kp, &p->list, list) { | |
387 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
388 | set_kprobe_instance(kp); | |
389 | kp->pre_handler(kp, regs); | |
390 | } | |
391 | reset_kprobe_instance(); | |
392 | } | |
393 | } | |
820aede0 | 394 | NOKPROBE_SYMBOL(opt_pre_handler); |
afd66255 | 395 | |
6274de49 | 396 | /* Free optimized instructions and optimized_kprobe */ |
55479f64 | 397 | static void free_aggr_kprobe(struct kprobe *p) |
6274de49 MH |
398 | { |
399 | struct optimized_kprobe *op; | |
400 | ||
401 | op = container_of(p, struct optimized_kprobe, kp); | |
402 | arch_remove_optimized_kprobe(op); | |
403 | arch_remove_kprobe(p); | |
404 | kfree(op); | |
405 | } | |
406 | ||
afd66255 MH |
407 | /* Return true(!0) if the kprobe is ready for optimization. */ |
408 | static inline int kprobe_optready(struct kprobe *p) | |
409 | { | |
410 | struct optimized_kprobe *op; | |
411 | ||
412 | if (kprobe_aggrprobe(p)) { | |
413 | op = container_of(p, struct optimized_kprobe, kp); | |
414 | return arch_prepared_optinsn(&op->optinsn); | |
415 | } | |
416 | ||
417 | return 0; | |
418 | } | |
419 | ||
6274de49 MH |
420 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
421 | static inline int kprobe_disarmed(struct kprobe *p) | |
422 | { | |
423 | struct optimized_kprobe *op; | |
424 | ||
425 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ | |
426 | if (!kprobe_aggrprobe(p)) | |
427 | return kprobe_disabled(p); | |
428 | ||
429 | op = container_of(p, struct optimized_kprobe, kp); | |
430 | ||
431 | return kprobe_disabled(p) && list_empty(&op->list); | |
432 | } | |
433 | ||
434 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ | |
55479f64 | 435 | static int kprobe_queued(struct kprobe *p) |
6274de49 MH |
436 | { |
437 | struct optimized_kprobe *op; | |
438 | ||
439 | if (kprobe_aggrprobe(p)) { | |
440 | op = container_of(p, struct optimized_kprobe, kp); | |
441 | if (!list_empty(&op->list)) | |
442 | return 1; | |
443 | } | |
444 | return 0; | |
445 | } | |
446 | ||
afd66255 MH |
447 | /* |
448 | * Return an optimized kprobe whose optimizing code replaces | |
449 | * instructions including addr (exclude breakpoint). | |
450 | */ | |
55479f64 | 451 | static struct kprobe *get_optimized_kprobe(unsigned long addr) |
afd66255 MH |
452 | { |
453 | int i; | |
454 | struct kprobe *p = NULL; | |
455 | struct optimized_kprobe *op; | |
456 | ||
457 | /* Don't check i == 0, since that is a breakpoint case. */ | |
458 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
459 | p = get_kprobe((void *)(addr - i)); | |
460 | ||
461 | if (p && kprobe_optready(p)) { | |
462 | op = container_of(p, struct optimized_kprobe, kp); | |
463 | if (arch_within_optimized_kprobe(op, addr)) | |
464 | return p; | |
465 | } | |
466 | ||
467 | return NULL; | |
468 | } | |
469 | ||
470 | /* Optimization staging list, protected by kprobe_mutex */ | |
471 | static LIST_HEAD(optimizing_list); | |
6274de49 | 472 | static LIST_HEAD(unoptimizing_list); |
7b959fc5 | 473 | static LIST_HEAD(freeing_list); |
afd66255 MH |
474 | |
475 | static void kprobe_optimizer(struct work_struct *work); | |
476 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
477 | #define OPTIMIZE_DELAY 5 | |
478 | ||
61f4e13f MH |
479 | /* |
480 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
481 | * optimizing_list. | |
482 | */ | |
55479f64 | 483 | static void do_optimize_kprobes(void) |
afd66255 | 484 | { |
6274de49 MH |
485 | /* Optimization never be done when disarmed */ |
486 | if (kprobes_all_disarmed || !kprobes_allow_optimization || | |
487 | list_empty(&optimizing_list)) | |
488 | return; | |
489 | ||
afd66255 MH |
490 | /* |
491 | * The optimization/unoptimization refers online_cpus via | |
492 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
493 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
494 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
495 | * text_mutex but stop_machine can not be done because online_cpus | |
496 | * has been changed) | |
497 | * To avoid this deadlock, we need to call get_online_cpus() | |
498 | * for preventing cpu-hotplug outside of text_mutex locking. | |
499 | */ | |
500 | get_online_cpus(); | |
501 | mutex_lock(&text_mutex); | |
cd7ebe22 | 502 | arch_optimize_kprobes(&optimizing_list); |
afd66255 MH |
503 | mutex_unlock(&text_mutex); |
504 | put_online_cpus(); | |
61f4e13f MH |
505 | } |
506 | ||
6274de49 MH |
507 | /* |
508 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint | |
509 | * if need) kprobes listed on unoptimizing_list. | |
510 | */ | |
55479f64 | 511 | static void do_unoptimize_kprobes(void) |
6274de49 MH |
512 | { |
513 | struct optimized_kprobe *op, *tmp; | |
514 | ||
515 | /* Unoptimization must be done anytime */ | |
516 | if (list_empty(&unoptimizing_list)) | |
517 | return; | |
518 | ||
519 | /* Ditto to do_optimize_kprobes */ | |
520 | get_online_cpus(); | |
521 | mutex_lock(&text_mutex); | |
7b959fc5 | 522 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
f984ba4e | 523 | /* Loop free_list for disarming */ |
7b959fc5 | 524 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 MH |
525 | /* Disarm probes if marked disabled */ |
526 | if (kprobe_disabled(&op->kp)) | |
527 | arch_disarm_kprobe(&op->kp); | |
528 | if (kprobe_unused(&op->kp)) { | |
529 | /* | |
530 | * Remove unused probes from hash list. After waiting | |
531 | * for synchronization, these probes are reclaimed. | |
532 | * (reclaiming is done by do_free_cleaned_kprobes.) | |
533 | */ | |
534 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
535 | } else |
536 | list_del_init(&op->list); | |
537 | } | |
538 | mutex_unlock(&text_mutex); | |
539 | put_online_cpus(); | |
540 | } | |
541 | ||
542 | /* Reclaim all kprobes on the free_list */ | |
55479f64 | 543 | static void do_free_cleaned_kprobes(void) |
6274de49 MH |
544 | { |
545 | struct optimized_kprobe *op, *tmp; | |
546 | ||
7b959fc5 | 547 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 MH |
548 | BUG_ON(!kprobe_unused(&op->kp)); |
549 | list_del_init(&op->list); | |
550 | free_aggr_kprobe(&op->kp); | |
551 | } | |
552 | } | |
553 | ||
554 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
55479f64 | 555 | static void kick_kprobe_optimizer(void) |
6274de49 | 556 | { |
ad72b3be | 557 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de49 MH |
558 | } |
559 | ||
61f4e13f | 560 | /* Kprobe jump optimizer */ |
55479f64 | 561 | static void kprobe_optimizer(struct work_struct *work) |
61f4e13f | 562 | { |
72ef3794 | 563 | mutex_lock(&kprobe_mutex); |
61f4e13f MH |
564 | /* Lock modules while optimizing kprobes */ |
565 | mutex_lock(&module_mutex); | |
61f4e13f MH |
566 | |
567 | /* | |
6274de49 MH |
568 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
569 | * kprobes before waiting for quiesence period. | |
570 | */ | |
7b959fc5 | 571 | do_unoptimize_kprobes(); |
6274de49 MH |
572 | |
573 | /* | |
574 | * Step 2: Wait for quiesence period to ensure all running interrupts | |
61f4e13f MH |
575 | * are done. Because optprobe may modify multiple instructions |
576 | * there is a chance that Nth instruction is interrupted. In that | |
577 | * case, running interrupt can return to 2nd-Nth byte of jump | |
578 | * instruction. This wait is for avoiding it. | |
579 | */ | |
580 | synchronize_sched(); | |
581 | ||
6274de49 | 582 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 583 | do_optimize_kprobes(); |
6274de49 MH |
584 | |
585 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
7b959fc5 | 586 | do_free_cleaned_kprobes(); |
6274de49 | 587 | |
afd66255 | 588 | mutex_unlock(&module_mutex); |
72ef3794 | 589 | mutex_unlock(&kprobe_mutex); |
6274de49 | 590 | |
cd7ebe22 | 591 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 592 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 | 593 | kick_kprobe_optimizer(); |
6274de49 MH |
594 | } |
595 | ||
596 | /* Wait for completing optimization and unoptimization */ | |
55479f64 | 597 | static void wait_for_kprobe_optimizer(void) |
6274de49 | 598 | { |
ad72b3be TH |
599 | mutex_lock(&kprobe_mutex); |
600 | ||
601 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { | |
602 | mutex_unlock(&kprobe_mutex); | |
603 | ||
604 | /* this will also make optimizing_work execute immmediately */ | |
605 | flush_delayed_work(&optimizing_work); | |
606 | /* @optimizing_work might not have been queued yet, relax */ | |
607 | cpu_relax(); | |
608 | ||
609 | mutex_lock(&kprobe_mutex); | |
610 | } | |
611 | ||
612 | mutex_unlock(&kprobe_mutex); | |
afd66255 MH |
613 | } |
614 | ||
615 | /* Optimize kprobe if p is ready to be optimized */ | |
55479f64 | 616 | static void optimize_kprobe(struct kprobe *p) |
afd66255 MH |
617 | { |
618 | struct optimized_kprobe *op; | |
619 | ||
620 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 621 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
622 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
623 | return; | |
624 | ||
625 | /* Both of break_handler and post_handler are not supported. */ | |
626 | if (p->break_handler || p->post_handler) | |
627 | return; | |
628 | ||
629 | op = container_of(p, struct optimized_kprobe, kp); | |
630 | ||
631 | /* Check there is no other kprobes at the optimized instructions */ | |
632 | if (arch_check_optimized_kprobe(op) < 0) | |
633 | return; | |
634 | ||
635 | /* Check if it is already optimized. */ | |
636 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) | |
637 | return; | |
afd66255 | 638 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 MH |
639 | |
640 | if (!list_empty(&op->list)) | |
641 | /* This is under unoptimizing. Just dequeue the probe */ | |
642 | list_del_init(&op->list); | |
643 | else { | |
644 | list_add(&op->list, &optimizing_list); | |
645 | kick_kprobe_optimizer(); | |
646 | } | |
647 | } | |
648 | ||
649 | /* Short cut to direct unoptimizing */ | |
55479f64 | 650 | static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
6274de49 MH |
651 | { |
652 | get_online_cpus(); | |
653 | arch_unoptimize_kprobe(op); | |
654 | put_online_cpus(); | |
655 | if (kprobe_disabled(&op->kp)) | |
656 | arch_disarm_kprobe(&op->kp); | |
afd66255 MH |
657 | } |
658 | ||
659 | /* Unoptimize a kprobe if p is optimized */ | |
55479f64 | 660 | static void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
661 | { |
662 | struct optimized_kprobe *op; | |
663 | ||
6274de49 MH |
664 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
665 | return; /* This is not an optprobe nor optimized */ | |
666 | ||
667 | op = container_of(p, struct optimized_kprobe, kp); | |
668 | if (!kprobe_optimized(p)) { | |
669 | /* Unoptimized or unoptimizing case */ | |
670 | if (force && !list_empty(&op->list)) { | |
671 | /* | |
672 | * Only if this is unoptimizing kprobe and forced, | |
673 | * forcibly unoptimize it. (No need to unoptimize | |
674 | * unoptimized kprobe again :) | |
675 | */ | |
afd66255 | 676 | list_del_init(&op->list); |
6274de49 MH |
677 | force_unoptimize_kprobe(op); |
678 | } | |
679 | return; | |
680 | } | |
681 | ||
682 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
683 | if (!list_empty(&op->list)) { | |
684 | /* Dequeue from the optimization queue */ | |
685 | list_del_init(&op->list); | |
686 | return; | |
687 | } | |
688 | /* Optimized kprobe case */ | |
689 | if (force) | |
690 | /* Forcibly update the code: this is a special case */ | |
691 | force_unoptimize_kprobe(op); | |
692 | else { | |
693 | list_add(&op->list, &unoptimizing_list); | |
694 | kick_kprobe_optimizer(); | |
afd66255 MH |
695 | } |
696 | } | |
697 | ||
0490cd1f MH |
698 | /* Cancel unoptimizing for reusing */ |
699 | static void reuse_unused_kprobe(struct kprobe *ap) | |
700 | { | |
701 | struct optimized_kprobe *op; | |
702 | ||
703 | BUG_ON(!kprobe_unused(ap)); | |
704 | /* | |
705 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
706 | * there is still a relative jump) and disabled. | |
707 | */ | |
708 | op = container_of(ap, struct optimized_kprobe, kp); | |
709 | if (unlikely(list_empty(&op->list))) | |
710 | printk(KERN_WARNING "Warning: found a stray unused " | |
711 | "aggrprobe@%p\n", ap->addr); | |
712 | /* Enable the probe again */ | |
713 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
714 | /* Optimize it again (remove from op->list) */ | |
715 | BUG_ON(!kprobe_optready(ap)); | |
716 | optimize_kprobe(ap); | |
717 | } | |
718 | ||
afd66255 | 719 | /* Remove optimized instructions */ |
55479f64 | 720 | static void kill_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
721 | { |
722 | struct optimized_kprobe *op; | |
723 | ||
724 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
725 | if (!list_empty(&op->list)) |
726 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 727 | list_del_init(&op->list); |
6274de49 | 728 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc5 MH |
729 | |
730 | if (kprobe_unused(p)) { | |
731 | /* Enqueue if it is unused */ | |
732 | list_add(&op->list, &freeing_list); | |
733 | /* | |
734 | * Remove unused probes from the hash list. After waiting | |
735 | * for synchronization, this probe is reclaimed. | |
736 | * (reclaiming is done by do_free_cleaned_kprobes().) | |
737 | */ | |
738 | hlist_del_rcu(&op->kp.hlist); | |
739 | } | |
740 | ||
6274de49 | 741 | /* Don't touch the code, because it is already freed. */ |
afd66255 MH |
742 | arch_remove_optimized_kprobe(op); |
743 | } | |
744 | ||
a460246c MH |
745 | static inline |
746 | void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) | |
747 | { | |
748 | if (!kprobe_ftrace(p)) | |
749 | arch_prepare_optimized_kprobe(op, p); | |
750 | } | |
751 | ||
afd66255 | 752 | /* Try to prepare optimized instructions */ |
55479f64 | 753 | static void prepare_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
754 | { |
755 | struct optimized_kprobe *op; | |
756 | ||
757 | op = container_of(p, struct optimized_kprobe, kp); | |
a460246c | 758 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
759 | } |
760 | ||
afd66255 | 761 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
55479f64 | 762 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
763 | { |
764 | struct optimized_kprobe *op; | |
765 | ||
766 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
767 | if (!op) | |
768 | return NULL; | |
769 | ||
770 | INIT_LIST_HEAD(&op->list); | |
771 | op->kp.addr = p->addr; | |
a460246c | 772 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
773 | |
774 | return &op->kp; | |
775 | } | |
776 | ||
55479f64 | 777 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
afd66255 MH |
778 | |
779 | /* | |
780 | * Prepare an optimized_kprobe and optimize it | |
781 | * NOTE: p must be a normal registered kprobe | |
782 | */ | |
55479f64 | 783 | static void try_to_optimize_kprobe(struct kprobe *p) |
afd66255 MH |
784 | { |
785 | struct kprobe *ap; | |
786 | struct optimized_kprobe *op; | |
787 | ||
ae6aa16f MH |
788 | /* Impossible to optimize ftrace-based kprobe */ |
789 | if (kprobe_ftrace(p)) | |
790 | return; | |
791 | ||
25764288 MH |
792 | /* For preparing optimization, jump_label_text_reserved() is called */ |
793 | jump_label_lock(); | |
794 | mutex_lock(&text_mutex); | |
795 | ||
afd66255 MH |
796 | ap = alloc_aggr_kprobe(p); |
797 | if (!ap) | |
25764288 | 798 | goto out; |
afd66255 MH |
799 | |
800 | op = container_of(ap, struct optimized_kprobe, kp); | |
801 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
802 | /* If failed to setup optimizing, fallback to kprobe */ | |
6274de49 MH |
803 | arch_remove_optimized_kprobe(op); |
804 | kfree(op); | |
25764288 | 805 | goto out; |
afd66255 MH |
806 | } |
807 | ||
808 | init_aggr_kprobe(ap, p); | |
25764288 MH |
809 | optimize_kprobe(ap); /* This just kicks optimizer thread */ |
810 | ||
811 | out: | |
812 | mutex_unlock(&text_mutex); | |
813 | jump_label_unlock(); | |
afd66255 MH |
814 | } |
815 | ||
b2be84df | 816 | #ifdef CONFIG_SYSCTL |
55479f64 | 817 | static void optimize_all_kprobes(void) |
b2be84df MH |
818 | { |
819 | struct hlist_head *head; | |
b2be84df MH |
820 | struct kprobe *p; |
821 | unsigned int i; | |
822 | ||
5c51543b | 823 | mutex_lock(&kprobe_mutex); |
b2be84df MH |
824 | /* If optimization is already allowed, just return */ |
825 | if (kprobes_allow_optimization) | |
5c51543b | 826 | goto out; |
b2be84df MH |
827 | |
828 | kprobes_allow_optimization = true; | |
b2be84df MH |
829 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
830 | head = &kprobe_table[i]; | |
b67bfe0d | 831 | hlist_for_each_entry_rcu(p, head, hlist) |
b2be84df MH |
832 | if (!kprobe_disabled(p)) |
833 | optimize_kprobe(p); | |
834 | } | |
b2be84df | 835 | printk(KERN_INFO "Kprobes globally optimized\n"); |
5c51543b MH |
836 | out: |
837 | mutex_unlock(&kprobe_mutex); | |
b2be84df MH |
838 | } |
839 | ||
55479f64 | 840 | static void unoptimize_all_kprobes(void) |
b2be84df MH |
841 | { |
842 | struct hlist_head *head; | |
b2be84df MH |
843 | struct kprobe *p; |
844 | unsigned int i; | |
845 | ||
5c51543b | 846 | mutex_lock(&kprobe_mutex); |
b2be84df | 847 | /* If optimization is already prohibited, just return */ |
5c51543b MH |
848 | if (!kprobes_allow_optimization) { |
849 | mutex_unlock(&kprobe_mutex); | |
b2be84df | 850 | return; |
5c51543b | 851 | } |
b2be84df MH |
852 | |
853 | kprobes_allow_optimization = false; | |
b2be84df MH |
854 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
855 | head = &kprobe_table[i]; | |
b67bfe0d | 856 | hlist_for_each_entry_rcu(p, head, hlist) { |
b2be84df | 857 | if (!kprobe_disabled(p)) |
6274de49 | 858 | unoptimize_kprobe(p, false); |
b2be84df MH |
859 | } |
860 | } | |
5c51543b MH |
861 | mutex_unlock(&kprobe_mutex); |
862 | ||
6274de49 MH |
863 | /* Wait for unoptimizing completion */ |
864 | wait_for_kprobe_optimizer(); | |
865 | printk(KERN_INFO "Kprobes globally unoptimized\n"); | |
b2be84df MH |
866 | } |
867 | ||
5c51543b | 868 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
b2be84df MH |
869 | int sysctl_kprobes_optimization; |
870 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, | |
871 | void __user *buffer, size_t *length, | |
872 | loff_t *ppos) | |
873 | { | |
874 | int ret; | |
875 | ||
5c51543b | 876 | mutex_lock(&kprobe_sysctl_mutex); |
b2be84df MH |
877 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
878 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
879 | ||
880 | if (sysctl_kprobes_optimization) | |
881 | optimize_all_kprobes(); | |
882 | else | |
883 | unoptimize_all_kprobes(); | |
5c51543b | 884 | mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df MH |
885 | |
886 | return ret; | |
887 | } | |
888 | #endif /* CONFIG_SYSCTL */ | |
889 | ||
6274de49 | 890 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
55479f64 | 891 | static void __arm_kprobe(struct kprobe *p) |
afd66255 | 892 | { |
6d8e40a8 | 893 | struct kprobe *_p; |
afd66255 MH |
894 | |
895 | /* Check collision with other optimized kprobes */ | |
6d8e40a8 MH |
896 | _p = get_optimized_kprobe((unsigned long)p->addr); |
897 | if (unlikely(_p)) | |
6274de49 MH |
898 | /* Fallback to unoptimized kprobe */ |
899 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
900 | |
901 | arch_arm_kprobe(p); | |
902 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
903 | } | |
904 | ||
6274de49 | 905 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
55479f64 | 906 | static void __disarm_kprobe(struct kprobe *p, bool reopt) |
afd66255 | 907 | { |
6d8e40a8 | 908 | struct kprobe *_p; |
afd66255 | 909 | |
69d54b91 WN |
910 | /* Try to unoptimize */ |
911 | unoptimize_kprobe(p, kprobes_all_disarmed); | |
afd66255 | 912 | |
6274de49 MH |
913 | if (!kprobe_queued(p)) { |
914 | arch_disarm_kprobe(p); | |
915 | /* If another kprobe was blocked, optimize it. */ | |
916 | _p = get_optimized_kprobe((unsigned long)p->addr); | |
917 | if (unlikely(_p) && reopt) | |
918 | optimize_kprobe(_p); | |
919 | } | |
920 | /* TODO: reoptimize others after unoptimized this probe */ | |
afd66255 MH |
921 | } |
922 | ||
923 | #else /* !CONFIG_OPTPROBES */ | |
924 | ||
925 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 926 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
927 | #define kill_optimized_kprobe(p) do {} while (0) |
928 | #define prepare_optimized_kprobe(p) do {} while (0) | |
929 | #define try_to_optimize_kprobe(p) do {} while (0) | |
930 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
931 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
932 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
933 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 934 | |
0490cd1f MH |
935 | /* There should be no unused kprobes can be reused without optimization */ |
936 | static void reuse_unused_kprobe(struct kprobe *ap) | |
937 | { | |
938 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); | |
939 | BUG_ON(kprobe_unused(ap)); | |
940 | } | |
941 | ||
55479f64 | 942 | static void free_aggr_kprobe(struct kprobe *p) |
afd66255 | 943 | { |
6274de49 | 944 | arch_remove_kprobe(p); |
afd66255 MH |
945 | kfree(p); |
946 | } | |
947 | ||
55479f64 | 948 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
949 | { |
950 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
951 | } | |
952 | #endif /* CONFIG_OPTPROBES */ | |
953 | ||
e7dbfe34 | 954 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 955 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
e5253896 | 956 | .func = kprobe_ftrace_handler, |
1d70be34 | 957 | .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
ae6aa16f MH |
958 | }; |
959 | static int kprobe_ftrace_enabled; | |
960 | ||
961 | /* Must ensure p->addr is really on ftrace */ | |
55479f64 | 962 | static int prepare_kprobe(struct kprobe *p) |
ae6aa16f MH |
963 | { |
964 | if (!kprobe_ftrace(p)) | |
965 | return arch_prepare_kprobe(p); | |
966 | ||
967 | return arch_prepare_kprobe_ftrace(p); | |
968 | } | |
969 | ||
970 | /* Caller must lock kprobe_mutex */ | |
55479f64 | 971 | static void arm_kprobe_ftrace(struct kprobe *p) |
ae6aa16f MH |
972 | { |
973 | int ret; | |
974 | ||
975 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
976 | (unsigned long)p->addr, 0, 0); | |
977 | WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
978 | kprobe_ftrace_enabled++; | |
979 | if (kprobe_ftrace_enabled == 1) { | |
980 | ret = register_ftrace_function(&kprobe_ftrace_ops); | |
981 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
982 | } | |
983 | } | |
984 | ||
985 | /* Caller must lock kprobe_mutex */ | |
55479f64 | 986 | static void disarm_kprobe_ftrace(struct kprobe *p) |
ae6aa16f MH |
987 | { |
988 | int ret; | |
989 | ||
990 | kprobe_ftrace_enabled--; | |
991 | if (kprobe_ftrace_enabled == 0) { | |
992 | ret = unregister_ftrace_function(&kprobe_ftrace_ops); | |
993 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
994 | } | |
995 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
996 | (unsigned long)p->addr, 1, 0); | |
997 | WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
998 | } | |
e7dbfe34 | 999 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
1000 | #define prepare_kprobe(p) arch_prepare_kprobe(p) |
1001 | #define arm_kprobe_ftrace(p) do {} while (0) | |
1002 | #define disarm_kprobe_ftrace(p) do {} while (0) | |
1003 | #endif | |
1004 | ||
201517a7 | 1005 | /* Arm a kprobe with text_mutex */ |
55479f64 | 1006 | static void arm_kprobe(struct kprobe *kp) |
201517a7 | 1007 | { |
ae6aa16f MH |
1008 | if (unlikely(kprobe_ftrace(kp))) { |
1009 | arm_kprobe_ftrace(kp); | |
1010 | return; | |
1011 | } | |
afd66255 MH |
1012 | /* |
1013 | * Here, since __arm_kprobe() doesn't use stop_machine(), | |
1014 | * this doesn't cause deadlock on text_mutex. So, we don't | |
1015 | * need get_online_cpus(). | |
1016 | */ | |
201517a7 | 1017 | mutex_lock(&text_mutex); |
afd66255 | 1018 | __arm_kprobe(kp); |
201517a7 MH |
1019 | mutex_unlock(&text_mutex); |
1020 | } | |
1021 | ||
1022 | /* Disarm a kprobe with text_mutex */ | |
55479f64 | 1023 | static void disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 1024 | { |
ae6aa16f MH |
1025 | if (unlikely(kprobe_ftrace(kp))) { |
1026 | disarm_kprobe_ftrace(kp); | |
1027 | return; | |
1028 | } | |
6274de49 | 1029 | /* Ditto */ |
201517a7 | 1030 | mutex_lock(&text_mutex); |
ae6aa16f | 1031 | __disarm_kprobe(kp, reopt); |
201517a7 MH |
1032 | mutex_unlock(&text_mutex); |
1033 | } | |
1034 | ||
64f562c6 AM |
1035 | /* |
1036 | * Aggregate handlers for multiple kprobes support - these handlers | |
1037 | * take care of invoking the individual kprobe handlers on p->list | |
1038 | */ | |
820aede0 | 1039 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
1040 | { |
1041 | struct kprobe *kp; | |
1042 | ||
3516a460 | 1043 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1044 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1045 | set_kprobe_instance(kp); |
8b0914ea PP |
1046 | if (kp->pre_handler(kp, regs)) |
1047 | return 1; | |
64f562c6 | 1048 | } |
e6584523 | 1049 | reset_kprobe_instance(); |
64f562c6 AM |
1050 | } |
1051 | return 0; | |
1052 | } | |
820aede0 | 1053 | NOKPROBE_SYMBOL(aggr_pre_handler); |
64f562c6 | 1054 | |
820aede0 MH |
1055 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1056 | unsigned long flags) | |
64f562c6 AM |
1057 | { |
1058 | struct kprobe *kp; | |
1059 | ||
3516a460 | 1060 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1061 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1062 | set_kprobe_instance(kp); |
64f562c6 | 1063 | kp->post_handler(kp, regs, flags); |
e6584523 | 1064 | reset_kprobe_instance(); |
64f562c6 AM |
1065 | } |
1066 | } | |
64f562c6 | 1067 | } |
820aede0 | 1068 | NOKPROBE_SYMBOL(aggr_post_handler); |
64f562c6 | 1069 | |
820aede0 MH |
1070 | static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
1071 | int trapnr) | |
64f562c6 | 1072 | { |
b76834bc | 1073 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 | 1074 | |
64f562c6 AM |
1075 | /* |
1076 | * if we faulted "during" the execution of a user specified | |
1077 | * probe handler, invoke just that probe's fault handler | |
1078 | */ | |
e6584523 AM |
1079 | if (cur && cur->fault_handler) { |
1080 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
1081 | return 1; |
1082 | } | |
1083 | return 0; | |
1084 | } | |
820aede0 | 1085 | NOKPROBE_SYMBOL(aggr_fault_handler); |
64f562c6 | 1086 | |
820aede0 | 1087 | static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 1088 | { |
b76834bc | 1089 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 AM |
1090 | int ret = 0; |
1091 | ||
1092 | if (cur && cur->break_handler) { | |
1093 | if (cur->break_handler(cur, regs)) | |
1094 | ret = 1; | |
8b0914ea | 1095 | } |
e6584523 AM |
1096 | reset_kprobe_instance(); |
1097 | return ret; | |
8b0914ea | 1098 | } |
820aede0 | 1099 | NOKPROBE_SYMBOL(aggr_break_handler); |
8b0914ea | 1100 | |
bf8d5c52 | 1101 | /* Walks the list and increments nmissed count for multiprobe case */ |
820aede0 | 1102 | void kprobes_inc_nmissed_count(struct kprobe *p) |
bf8d5c52 KA |
1103 | { |
1104 | struct kprobe *kp; | |
afd66255 | 1105 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1106 | p->nmissed++; |
1107 | } else { | |
1108 | list_for_each_entry_rcu(kp, &p->list, list) | |
1109 | kp->nmissed++; | |
1110 | } | |
1111 | return; | |
1112 | } | |
820aede0 | 1113 | NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
bf8d5c52 | 1114 | |
820aede0 MH |
1115 | void recycle_rp_inst(struct kretprobe_instance *ri, |
1116 | struct hlist_head *head) | |
b94cce92 | 1117 | { |
ef53d9c5 S |
1118 | struct kretprobe *rp = ri->rp; |
1119 | ||
b94cce92 HN |
1120 | /* remove rp inst off the rprobe_inst_table */ |
1121 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
1122 | INIT_HLIST_NODE(&ri->hlist); |
1123 | if (likely(rp)) { | |
ec484608 | 1124 | raw_spin_lock(&rp->lock); |
ef53d9c5 | 1125 | hlist_add_head(&ri->hlist, &rp->free_instances); |
ec484608 | 1126 | raw_spin_unlock(&rp->lock); |
b94cce92 HN |
1127 | } else |
1128 | /* Unregistering */ | |
99219a3f | 1129 | hlist_add_head(&ri->hlist, head); |
b94cce92 | 1130 | } |
820aede0 | 1131 | NOKPROBE_SYMBOL(recycle_rp_inst); |
b94cce92 | 1132 | |
820aede0 | 1133 | void kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 | 1134 | struct hlist_head **head, unsigned long *flags) |
635c17c2 | 1135 | __acquires(hlist_lock) |
ef53d9c5 S |
1136 | { |
1137 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1138 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1139 | |
1140 | *head = &kretprobe_inst_table[hash]; | |
1141 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1142 | raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5 | 1143 | } |
820aede0 | 1144 | NOKPROBE_SYMBOL(kretprobe_hash_lock); |
ef53d9c5 | 1145 | |
820aede0 MH |
1146 | static void kretprobe_table_lock(unsigned long hash, |
1147 | unsigned long *flags) | |
635c17c2 | 1148 | __acquires(hlist_lock) |
b94cce92 | 1149 | { |
ec484608 TG |
1150 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1151 | raw_spin_lock_irqsave(hlist_lock, *flags); | |
ef53d9c5 | 1152 | } |
820aede0 | 1153 | NOKPROBE_SYMBOL(kretprobe_table_lock); |
ef53d9c5 | 1154 | |
820aede0 MH |
1155 | void kretprobe_hash_unlock(struct task_struct *tsk, |
1156 | unsigned long *flags) | |
635c17c2 | 1157 | __releases(hlist_lock) |
ef53d9c5 S |
1158 | { |
1159 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1160 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1161 | |
1162 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1163 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
ef53d9c5 | 1164 | } |
820aede0 | 1165 | NOKPROBE_SYMBOL(kretprobe_hash_unlock); |
ef53d9c5 | 1166 | |
820aede0 MH |
1167 | static void kretprobe_table_unlock(unsigned long hash, |
1168 | unsigned long *flags) | |
635c17c2 | 1169 | __releases(hlist_lock) |
ef53d9c5 | 1170 | { |
ec484608 TG |
1171 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1172 | raw_spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 | 1173 | } |
820aede0 | 1174 | NOKPROBE_SYMBOL(kretprobe_table_unlock); |
b94cce92 | 1175 | |
b94cce92 | 1176 | /* |
c6fd91f0 | 1177 | * This function is called from finish_task_switch when task tk becomes dead, |
1178 | * so that we can recycle any function-return probe instances associated | |
1179 | * with this task. These left over instances represent probed functions | |
1180 | * that have been called but will never return. | |
b94cce92 | 1181 | */ |
820aede0 | 1182 | void kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 1183 | { |
62c27be0 | 1184 | struct kretprobe_instance *ri; |
99219a3f | 1185 | struct hlist_head *head, empty_rp; |
b67bfe0d | 1186 | struct hlist_node *tmp; |
ef53d9c5 | 1187 | unsigned long hash, flags = 0; |
802eae7c | 1188 | |
ef53d9c5 S |
1189 | if (unlikely(!kprobes_initialized)) |
1190 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
1191 | return; | |
1192 | ||
d496aab5 | 1193 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 S |
1194 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1195 | head = &kretprobe_inst_table[hash]; | |
1196 | kretprobe_table_lock(hash, &flags); | |
b67bfe0d | 1197 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
62c27be0 | 1198 | if (ri->task == tk) |
99219a3f | 1199 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 1200 | } |
ef53d9c5 | 1201 | kretprobe_table_unlock(hash, &flags); |
b67bfe0d | 1202 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
99219a3f | 1203 | hlist_del(&ri->hlist); |
1204 | kfree(ri); | |
1205 | } | |
b94cce92 | 1206 | } |
820aede0 | 1207 | NOKPROBE_SYMBOL(kprobe_flush_task); |
b94cce92 | 1208 | |
b94cce92 HN |
1209 | static inline void free_rp_inst(struct kretprobe *rp) |
1210 | { | |
1211 | struct kretprobe_instance *ri; | |
b67bfe0d | 1212 | struct hlist_node *next; |
4c4308cb | 1213 | |
b67bfe0d | 1214 | hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) { |
ef53d9c5 | 1215 | hlist_del(&ri->hlist); |
b94cce92 HN |
1216 | kfree(ri); |
1217 | } | |
1218 | } | |
1219 | ||
820aede0 | 1220 | static void cleanup_rp_inst(struct kretprobe *rp) |
4a296e07 | 1221 | { |
ef53d9c5 | 1222 | unsigned long flags, hash; |
4a296e07 | 1223 | struct kretprobe_instance *ri; |
b67bfe0d | 1224 | struct hlist_node *next; |
ef53d9c5 S |
1225 | struct hlist_head *head; |
1226 | ||
4a296e07 | 1227 | /* No race here */ |
ef53d9c5 S |
1228 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1229 | kretprobe_table_lock(hash, &flags); | |
1230 | head = &kretprobe_inst_table[hash]; | |
b67bfe0d | 1231 | hlist_for_each_entry_safe(ri, next, head, hlist) { |
ef53d9c5 S |
1232 | if (ri->rp == rp) |
1233 | ri->rp = NULL; | |
1234 | } | |
1235 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 1236 | } |
4a296e07 MH |
1237 | free_rp_inst(rp); |
1238 | } | |
820aede0 | 1239 | NOKPROBE_SYMBOL(cleanup_rp_inst); |
4a296e07 | 1240 | |
8b0914ea | 1241 | /* |
b918e5e6 | 1242 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
1243 | * second jprobe at the address - two jprobes can't coexist |
1244 | */ | |
55479f64 | 1245 | static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1246 | { |
de5bd88d | 1247 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
afd66255 MH |
1248 | |
1249 | if (p->break_handler || p->post_handler) | |
6274de49 | 1250 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1251 | |
8b0914ea | 1252 | if (p->break_handler) { |
b918e5e6 | 1253 | if (ap->break_handler) |
36721656 | 1254 | return -EEXIST; |
b918e5e6 MH |
1255 | list_add_tail_rcu(&p->list, &ap->list); |
1256 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 1257 | } else |
b918e5e6 MH |
1258 | list_add_rcu(&p->list, &ap->list); |
1259 | if (p->post_handler && !ap->post_handler) | |
1260 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1261 | |
8b0914ea PP |
1262 | return 0; |
1263 | } | |
1264 | ||
64f562c6 AM |
1265 | /* |
1266 | * Fill in the required fields of the "manager kprobe". Replace the | |
1267 | * earlier kprobe in the hlist with the manager kprobe | |
1268 | */ | |
55479f64 | 1269 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1270 | { |
afd66255 | 1271 | /* Copy p's insn slot to ap */ |
8b0914ea | 1272 | copy_kprobe(p, ap); |
a9ad965e | 1273 | flush_insn_slot(ap); |
64f562c6 | 1274 | ap->addr = p->addr; |
afd66255 | 1275 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1276 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 1277 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
1278 | /* We don't care the kprobe which has gone. */ |
1279 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1280 | ap->post_handler = aggr_post_handler; |
e8386a0c | 1281 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 1282 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
1283 | |
1284 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1285 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1286 | |
afd66255 | 1287 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1288 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1289 | } |
1290 | ||
1291 | /* | |
1292 | * This is the second or subsequent kprobe at the address - handle | |
1293 | * the intricacies | |
64f562c6 | 1294 | */ |
55479f64 | 1295 | static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
64f562c6 AM |
1296 | { |
1297 | int ret = 0; | |
6d8e40a8 | 1298 | struct kprobe *ap = orig_p; |
64f562c6 | 1299 | |
25764288 MH |
1300 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1301 | jump_label_lock(); | |
1302 | /* | |
1303 | * Get online CPUs to avoid text_mutex deadlock.with stop machine, | |
1304 | * which is invoked by unoptimize_kprobe() in add_new_kprobe() | |
1305 | */ | |
1306 | get_online_cpus(); | |
1307 | mutex_lock(&text_mutex); | |
1308 | ||
6d8e40a8 MH |
1309 | if (!kprobe_aggrprobe(orig_p)) { |
1310 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
1311 | ap = alloc_aggr_kprobe(orig_p); | |
25764288 MH |
1312 | if (!ap) { |
1313 | ret = -ENOMEM; | |
1314 | goto out; | |
1315 | } | |
6d8e40a8 | 1316 | init_aggr_kprobe(ap, orig_p); |
6274de49 | 1317 | } else if (kprobe_unused(ap)) |
0490cd1f MH |
1318 | /* This probe is going to die. Rescue it */ |
1319 | reuse_unused_kprobe(ap); | |
b918e5e6 MH |
1320 | |
1321 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1322 | /* |
1323 | * Attempting to insert new probe at the same location that | |
1324 | * had a probe in the module vaddr area which already | |
1325 | * freed. So, the instruction slot has already been | |
1326 | * released. We need a new slot for the new probe. | |
1327 | */ | |
b918e5e6 | 1328 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1329 | if (ret) |
b918e5e6 MH |
1330 | /* |
1331 | * Even if fail to allocate new slot, don't need to | |
1332 | * free aggr_probe. It will be used next time, or | |
1333 | * freed by unregister_kprobe. | |
1334 | */ | |
25764288 | 1335 | goto out; |
de5bd88d | 1336 | |
afd66255 MH |
1337 | /* Prepare optimized instructions if possible. */ |
1338 | prepare_optimized_kprobe(ap); | |
1339 | ||
e8386a0c | 1340 | /* |
de5bd88d MH |
1341 | * Clear gone flag to prevent allocating new slot again, and |
1342 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1343 | */ |
de5bd88d MH |
1344 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1345 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1346 | } |
b918e5e6 | 1347 | |
afd66255 | 1348 | /* Copy ap's insn slot to p */ |
b918e5e6 | 1349 | copy_kprobe(ap, p); |
25764288 MH |
1350 | ret = add_new_kprobe(ap, p); |
1351 | ||
1352 | out: | |
1353 | mutex_unlock(&text_mutex); | |
1354 | put_online_cpus(); | |
1355 | jump_label_unlock(); | |
1356 | ||
1357 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1358 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
1359 | if (!kprobes_all_disarmed) | |
1360 | /* Arm the breakpoint again. */ | |
1361 | arm_kprobe(ap); | |
1362 | } | |
1363 | return ret; | |
64f562c6 AM |
1364 | } |
1365 | ||
be8f2743 MH |
1366 | bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
1367 | { | |
1368 | /* The __kprobes marked functions and entry code must not be probed */ | |
1369 | return addr >= (unsigned long)__kprobes_text_start && | |
1370 | addr < (unsigned long)__kprobes_text_end; | |
1371 | } | |
1372 | ||
e5779e8e | 1373 | bool within_kprobe_blacklist(unsigned long addr) |
d0aaff97 | 1374 | { |
376e2424 | 1375 | struct kprobe_blacklist_entry *ent; |
3d8d996e | 1376 | |
be8f2743 | 1377 | if (arch_within_kprobe_blacklist(addr)) |
376e2424 | 1378 | return true; |
3d8d996e SD |
1379 | /* |
1380 | * If there exists a kprobe_blacklist, verify and | |
1381 | * fail any probe registration in the prohibited area | |
1382 | */ | |
376e2424 MH |
1383 | list_for_each_entry(ent, &kprobe_blacklist, list) { |
1384 | if (addr >= ent->start_addr && addr < ent->end_addr) | |
1385 | return true; | |
3d8d996e | 1386 | } |
376e2424 MH |
1387 | |
1388 | return false; | |
d0aaff97 PP |
1389 | } |
1390 | ||
b2a5cd69 MH |
1391 | /* |
1392 | * If we have a symbol_name argument, look it up and add the offset field | |
1393 | * to it. This way, we can specify a relative address to a symbol. | |
bc81d48d MH |
1394 | * This returns encoded errors if it fails to look up symbol or invalid |
1395 | * combination of parameters. | |
b2a5cd69 | 1396 | */ |
55479f64 | 1397 | static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
b2a5cd69 MH |
1398 | { |
1399 | kprobe_opcode_t *addr = p->addr; | |
bc81d48d MH |
1400 | |
1401 | if ((p->symbol_name && p->addr) || | |
1402 | (!p->symbol_name && !p->addr)) | |
1403 | goto invalid; | |
1404 | ||
b2a5cd69 | 1405 | if (p->symbol_name) { |
49e0b465 | 1406 | addr = kprobe_lookup_name(p->symbol_name); |
bc81d48d MH |
1407 | if (!addr) |
1408 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1409 | } |
1410 | ||
bc81d48d MH |
1411 | addr = (kprobe_opcode_t *)(((char *)addr) + p->offset); |
1412 | if (addr) | |
1413 | return addr; | |
1414 | ||
1415 | invalid: | |
1416 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1417 | } |
1418 | ||
1f0ab409 | 1419 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
55479f64 | 1420 | static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
1f0ab409 | 1421 | { |
6d8e40a8 | 1422 | struct kprobe *ap, *list_p; |
1f0ab409 | 1423 | |
6d8e40a8 MH |
1424 | ap = get_kprobe(p->addr); |
1425 | if (unlikely(!ap)) | |
1f0ab409 AM |
1426 | return NULL; |
1427 | ||
6d8e40a8 MH |
1428 | if (p != ap) { |
1429 | list_for_each_entry_rcu(list_p, &ap->list, list) | |
1f0ab409 AM |
1430 | if (list_p == p) |
1431 | /* kprobe p is a valid probe */ | |
1432 | goto valid; | |
1433 | return NULL; | |
1434 | } | |
1435 | valid: | |
6d8e40a8 | 1436 | return ap; |
1f0ab409 AM |
1437 | } |
1438 | ||
1439 | /* Return error if the kprobe is being re-registered */ | |
1440 | static inline int check_kprobe_rereg(struct kprobe *p) | |
1441 | { | |
1442 | int ret = 0; | |
1f0ab409 AM |
1443 | |
1444 | mutex_lock(&kprobe_mutex); | |
6d8e40a8 | 1445 | if (__get_valid_kprobe(p)) |
1f0ab409 AM |
1446 | ret = -EINVAL; |
1447 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1448 | |
1f0ab409 AM |
1449 | return ret; |
1450 | } | |
1451 | ||
f7f242ff | 1452 | int __weak arch_check_ftrace_location(struct kprobe *p) |
1da177e4 | 1453 | { |
ae6aa16f MH |
1454 | unsigned long ftrace_addr; |
1455 | ||
ae6aa16f MH |
1456 | ftrace_addr = ftrace_location((unsigned long)p->addr); |
1457 | if (ftrace_addr) { | |
e7dbfe34 | 1458 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f MH |
1459 | /* Given address is not on the instruction boundary */ |
1460 | if ((unsigned long)p->addr != ftrace_addr) | |
1461 | return -EILSEQ; | |
ae6aa16f | 1462 | p->flags |= KPROBE_FLAG_FTRACE; |
e7dbfe34 | 1463 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
1464 | return -EINVAL; |
1465 | #endif | |
1466 | } | |
f7f242ff HC |
1467 | return 0; |
1468 | } | |
1469 | ||
1470 | static int check_kprobe_address_safe(struct kprobe *p, | |
1471 | struct module **probed_mod) | |
1472 | { | |
1473 | int ret; | |
1f0ab409 | 1474 | |
f7f242ff HC |
1475 | ret = arch_check_ftrace_location(p); |
1476 | if (ret) | |
1477 | return ret; | |
91bad2f8 | 1478 | jump_label_lock(); |
de31c3ca | 1479 | preempt_disable(); |
f7fa6ef0 MH |
1480 | |
1481 | /* Ensure it is not in reserved area nor out of text */ | |
ec30c5f3 | 1482 | if (!kernel_text_address((unsigned long) p->addr) || |
376e2424 | 1483 | within_kprobe_blacklist((unsigned long) p->addr) || |
f986a499 PN |
1484 | jump_label_text_reserved(p->addr, p->addr)) { |
1485 | ret = -EINVAL; | |
f7fa6ef0 | 1486 | goto out; |
f986a499 | 1487 | } |
b3e55c72 | 1488 | |
f7fa6ef0 MH |
1489 | /* Check if are we probing a module */ |
1490 | *probed_mod = __module_text_address((unsigned long) p->addr); | |
1491 | if (*probed_mod) { | |
6f716acd | 1492 | /* |
e8386a0c MH |
1493 | * We must hold a refcount of the probed module while updating |
1494 | * its code to prohibit unexpected unloading. | |
df019b1d | 1495 | */ |
f7fa6ef0 MH |
1496 | if (unlikely(!try_module_get(*probed_mod))) { |
1497 | ret = -ENOENT; | |
1498 | goto out; | |
1499 | } | |
de31c3ca | 1500 | |
f24659d9 MH |
1501 | /* |
1502 | * If the module freed .init.text, we couldn't insert | |
1503 | * kprobes in there. | |
1504 | */ | |
f7fa6ef0 MH |
1505 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
1506 | (*probed_mod)->state != MODULE_STATE_COMING) { | |
1507 | module_put(*probed_mod); | |
1508 | *probed_mod = NULL; | |
1509 | ret = -ENOENT; | |
f24659d9 | 1510 | } |
df019b1d | 1511 | } |
f7fa6ef0 | 1512 | out: |
a189d035 | 1513 | preempt_enable(); |
de31c3ca | 1514 | jump_label_unlock(); |
1da177e4 | 1515 | |
f7fa6ef0 MH |
1516 | return ret; |
1517 | } | |
1518 | ||
55479f64 | 1519 | int register_kprobe(struct kprobe *p) |
f7fa6ef0 MH |
1520 | { |
1521 | int ret; | |
1522 | struct kprobe *old_p; | |
1523 | struct module *probed_mod; | |
1524 | kprobe_opcode_t *addr; | |
1525 | ||
1526 | /* Adjust probe address from symbol */ | |
1527 | addr = kprobe_addr(p); | |
1528 | if (IS_ERR(addr)) | |
1529 | return PTR_ERR(addr); | |
1530 | p->addr = addr; | |
1531 | ||
1532 | ret = check_kprobe_rereg(p); | |
1533 | if (ret) | |
1534 | return ret; | |
1535 | ||
1536 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ | |
1537 | p->flags &= KPROBE_FLAG_DISABLED; | |
3516a460 | 1538 | p->nmissed = 0; |
9861668f | 1539 | INIT_LIST_HEAD(&p->list); |
afd66255 | 1540 | |
f7fa6ef0 MH |
1541 | ret = check_kprobe_address_safe(p, &probed_mod); |
1542 | if (ret) | |
1543 | return ret; | |
1544 | ||
1545 | mutex_lock(&kprobe_mutex); | |
afd66255 | 1546 | |
64f562c6 AM |
1547 | old_p = get_kprobe(p->addr); |
1548 | if (old_p) { | |
afd66255 | 1549 | /* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6 | 1550 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1551 | goto out; |
1552 | } | |
1da177e4 | 1553 | |
25764288 | 1554 | mutex_lock(&text_mutex); /* Avoiding text modification */ |
ae6aa16f | 1555 | ret = prepare_kprobe(p); |
25764288 | 1556 | mutex_unlock(&text_mutex); |
6f716acd | 1557 | if (ret) |
afd66255 | 1558 | goto out; |
49a2a1b8 | 1559 | |
64f562c6 | 1560 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1561 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1562 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1563 | ||
de5bd88d | 1564 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
25764288 | 1565 | arm_kprobe(p); |
afd66255 MH |
1566 | |
1567 | /* Try to optimize kprobe */ | |
1568 | try_to_optimize_kprobe(p); | |
74a0b576 | 1569 | |
1da177e4 | 1570 | out: |
7a7d1cf9 | 1571 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1572 | |
e8386a0c | 1573 | if (probed_mod) |
df019b1d | 1574 | module_put(probed_mod); |
e8386a0c | 1575 | |
1da177e4 LT |
1576 | return ret; |
1577 | } | |
99081ab5 | 1578 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1579 | |
6f0f1dd7 | 1580 | /* Check if all probes on the aggrprobe are disabled */ |
55479f64 | 1581 | static int aggr_kprobe_disabled(struct kprobe *ap) |
6f0f1dd7 MH |
1582 | { |
1583 | struct kprobe *kp; | |
1584 | ||
1585 | list_for_each_entry_rcu(kp, &ap->list, list) | |
1586 | if (!kprobe_disabled(kp)) | |
1587 | /* | |
1588 | * There is an active probe on the list. | |
1589 | * We can't disable this ap. | |
1590 | */ | |
1591 | return 0; | |
1592 | ||
1593 | return 1; | |
1594 | } | |
1595 | ||
1596 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ | |
55479f64 | 1597 | static struct kprobe *__disable_kprobe(struct kprobe *p) |
6f0f1dd7 MH |
1598 | { |
1599 | struct kprobe *orig_p; | |
1600 | ||
1601 | /* Get an original kprobe for return */ | |
1602 | orig_p = __get_valid_kprobe(p); | |
1603 | if (unlikely(orig_p == NULL)) | |
1604 | return NULL; | |
1605 | ||
1606 | if (!kprobe_disabled(p)) { | |
1607 | /* Disable probe if it is a child probe */ | |
1608 | if (p != orig_p) | |
1609 | p->flags |= KPROBE_FLAG_DISABLED; | |
1610 | ||
1611 | /* Try to disarm and disable this/parent probe */ | |
1612 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
69d54b91 WN |
1613 | /* |
1614 | * If kprobes_all_disarmed is set, orig_p | |
1615 | * should have already been disarmed, so | |
1616 | * skip unneed disarming process. | |
1617 | */ | |
1618 | if (!kprobes_all_disarmed) | |
1619 | disarm_kprobe(orig_p, true); | |
6f0f1dd7 MH |
1620 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1621 | } | |
1622 | } | |
1623 | ||
1624 | return orig_p; | |
1625 | } | |
1626 | ||
de5bd88d MH |
1627 | /* |
1628 | * Unregister a kprobe without a scheduler synchronization. | |
1629 | */ | |
55479f64 | 1630 | static int __unregister_kprobe_top(struct kprobe *p) |
de5bd88d | 1631 | { |
6d8e40a8 | 1632 | struct kprobe *ap, *list_p; |
de5bd88d | 1633 | |
6f0f1dd7 MH |
1634 | /* Disable kprobe. This will disarm it if needed. */ |
1635 | ap = __disable_kprobe(p); | |
6d8e40a8 | 1636 | if (ap == NULL) |
de5bd88d MH |
1637 | return -EINVAL; |
1638 | ||
6f0f1dd7 | 1639 | if (ap == p) |
bf8f6e5b | 1640 | /* |
6f0f1dd7 MH |
1641 | * This probe is an independent(and non-optimized) kprobe |
1642 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1643 | */ |
6f0f1dd7 MH |
1644 | goto disarmed; |
1645 | ||
1646 | /* Following process expects this probe is an aggrprobe */ | |
1647 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1648 | ||
6274de49 MH |
1649 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1650 | /* | |
1651 | * !disarmed could be happen if the probe is under delayed | |
1652 | * unoptimizing. | |
1653 | */ | |
6f0f1dd7 MH |
1654 | goto disarmed; |
1655 | else { | |
1656 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1657 | if (p->break_handler && !kprobe_gone(p)) |
6d8e40a8 | 1658 | ap->break_handler = NULL; |
e8386a0c | 1659 | if (p->post_handler && !kprobe_gone(p)) { |
6d8e40a8 | 1660 | list_for_each_entry_rcu(list_p, &ap->list, list) { |
9861668f MH |
1661 | if ((list_p != p) && (list_p->post_handler)) |
1662 | goto noclean; | |
1663 | } | |
6d8e40a8 | 1664 | ap->post_handler = NULL; |
9861668f MH |
1665 | } |
1666 | noclean: | |
6f0f1dd7 MH |
1667 | /* |
1668 | * Remove from the aggrprobe: this path will do nothing in | |
1669 | * __unregister_kprobe_bottom(). | |
1670 | */ | |
49a2a1b8 | 1671 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1672 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1673 | /* | |
1674 | * Try to optimize this probe again, because post | |
1675 | * handler may have been changed. | |
1676 | */ | |
1677 | optimize_kprobe(ap); | |
49a2a1b8 | 1678 | } |
9861668f | 1679 | return 0; |
6f0f1dd7 MH |
1680 | |
1681 | disarmed: | |
6274de49 | 1682 | BUG_ON(!kprobe_disarmed(ap)); |
6f0f1dd7 MH |
1683 | hlist_del_rcu(&ap->hlist); |
1684 | return 0; | |
9861668f | 1685 | } |
3516a460 | 1686 | |
55479f64 | 1687 | static void __unregister_kprobe_bottom(struct kprobe *p) |
9861668f | 1688 | { |
6d8e40a8 | 1689 | struct kprobe *ap; |
b3e55c72 | 1690 | |
e8386a0c | 1691 | if (list_empty(&p->list)) |
6274de49 | 1692 | /* This is an independent kprobe */ |
0498b635 | 1693 | arch_remove_kprobe(p); |
e8386a0c | 1694 | else if (list_is_singular(&p->list)) { |
6274de49 | 1695 | /* This is the last child of an aggrprobe */ |
6d8e40a8 | 1696 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1697 | list_del(&p->list); |
6d8e40a8 | 1698 | free_aggr_kprobe(ap); |
9861668f | 1699 | } |
6274de49 | 1700 | /* Otherwise, do nothing. */ |
9861668f MH |
1701 | } |
1702 | ||
55479f64 | 1703 | int register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1704 | { |
1705 | int i, ret = 0; | |
1706 | ||
1707 | if (num <= 0) | |
1708 | return -EINVAL; | |
1709 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1710 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1711 | if (ret < 0) { |
1712 | if (i > 0) | |
1713 | unregister_kprobes(kps, i); | |
9861668f | 1714 | break; |
36721656 | 1715 | } |
49a2a1b8 | 1716 | } |
9861668f MH |
1717 | return ret; |
1718 | } | |
99081ab5 | 1719 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1720 | |
55479f64 | 1721 | void unregister_kprobe(struct kprobe *p) |
9861668f MH |
1722 | { |
1723 | unregister_kprobes(&p, 1); | |
1724 | } | |
99081ab5 | 1725 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1726 | |
55479f64 | 1727 | void unregister_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1728 | { |
1729 | int i; | |
1730 | ||
1731 | if (num <= 0) | |
1732 | return; | |
1733 | mutex_lock(&kprobe_mutex); | |
1734 | for (i = 0; i < num; i++) | |
1735 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1736 | kps[i]->addr = NULL; | |
1737 | mutex_unlock(&kprobe_mutex); | |
1738 | ||
1739 | synchronize_sched(); | |
1740 | for (i = 0; i < num; i++) | |
1741 | if (kps[i]->addr) | |
1742 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1743 | } |
99081ab5 | 1744 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 | 1745 | |
fc62d020 NR |
1746 | int __weak __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
1747 | unsigned long val, void *data) | |
1748 | { | |
1749 | return NOTIFY_DONE; | |
1750 | } | |
1751 | ||
1da177e4 | 1752 | static struct notifier_block kprobe_exceptions_nb = { |
3d5631e0 AK |
1753 | .notifier_call = kprobe_exceptions_notify, |
1754 | .priority = 0x7fffffff /* we need to be notified first */ | |
1755 | }; | |
1756 | ||
3d7e3382 ME |
1757 | unsigned long __weak arch_deref_entry_point(void *entry) |
1758 | { | |
1759 | return (unsigned long)entry; | |
1760 | } | |
1da177e4 | 1761 | |
55479f64 | 1762 | int register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 1763 | { |
26b31c19 MH |
1764 | struct jprobe *jp; |
1765 | int ret = 0, i; | |
3d7e3382 | 1766 | |
26b31c19 | 1767 | if (num <= 0) |
3d7e3382 | 1768 | return -EINVAL; |
26b31c19 | 1769 | for (i = 0; i < num; i++) { |
05662bdb | 1770 | unsigned long addr, offset; |
26b31c19 MH |
1771 | jp = jps[i]; |
1772 | addr = arch_deref_entry_point(jp->entry); | |
1773 | ||
05662bdb NK |
1774 | /* Verify probepoint is a function entry point */ |
1775 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && | |
1776 | offset == 0) { | |
1777 | jp->kp.pre_handler = setjmp_pre_handler; | |
1778 | jp->kp.break_handler = longjmp_break_handler; | |
1779 | ret = register_kprobe(&jp->kp); | |
1780 | } else | |
1781 | ret = -EINVAL; | |
edbaadbe | 1782 | |
67dddaad MH |
1783 | if (ret < 0) { |
1784 | if (i > 0) | |
1785 | unregister_jprobes(jps, i); | |
26b31c19 MH |
1786 | break; |
1787 | } | |
1788 | } | |
1789 | return ret; | |
1790 | } | |
99081ab5 | 1791 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 1792 | |
55479f64 | 1793 | int register_jprobe(struct jprobe *jp) |
26b31c19 | 1794 | { |
49ad2fd7 | 1795 | return register_jprobes(&jp, 1); |
1da177e4 | 1796 | } |
99081ab5 | 1797 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 1798 | |
55479f64 | 1799 | void unregister_jprobe(struct jprobe *jp) |
1da177e4 | 1800 | { |
26b31c19 MH |
1801 | unregister_jprobes(&jp, 1); |
1802 | } | |
99081ab5 | 1803 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 1804 | |
55479f64 | 1805 | void unregister_jprobes(struct jprobe **jps, int num) |
26b31c19 MH |
1806 | { |
1807 | int i; | |
1808 | ||
1809 | if (num <= 0) | |
1810 | return; | |
1811 | mutex_lock(&kprobe_mutex); | |
1812 | for (i = 0; i < num; i++) | |
1813 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
1814 | jps[i]->kp.addr = NULL; | |
1815 | mutex_unlock(&kprobe_mutex); | |
1816 | ||
1817 | synchronize_sched(); | |
1818 | for (i = 0; i < num; i++) { | |
1819 | if (jps[i]->kp.addr) | |
1820 | __unregister_kprobe_bottom(&jps[i]->kp); | |
1821 | } | |
1da177e4 | 1822 | } |
99081ab5 | 1823 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 1824 | |
9edddaa2 | 1825 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1826 | /* |
1827 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1828 | * hits it will set up the return probe. | |
1829 | */ | |
820aede0 | 1830 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
e65cefe8 AB |
1831 | { |
1832 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1833 | unsigned long hash, flags = 0; |
1834 | struct kretprobe_instance *ri; | |
e65cefe8 | 1835 | |
f96f5678 MH |
1836 | /* |
1837 | * To avoid deadlocks, prohibit return probing in NMI contexts, | |
1838 | * just skip the probe and increase the (inexact) 'nmissed' | |
1839 | * statistical counter, so that the user is informed that | |
1840 | * something happened: | |
1841 | */ | |
1842 | if (unlikely(in_nmi())) { | |
1843 | rp->nmissed++; | |
1844 | return 0; | |
1845 | } | |
1846 | ||
1847 | /* TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 | 1848 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
ec484608 | 1849 | raw_spin_lock_irqsave(&rp->lock, flags); |
4c4308cb | 1850 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1851 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1852 | struct kretprobe_instance, hlist); |
1853 | hlist_del(&ri->hlist); | |
ec484608 | 1854 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1855 | |
4c4308cb CH |
1856 | ri->rp = rp; |
1857 | ri->task = current; | |
f47cd9b5 | 1858 | |
55ca6140 JL |
1859 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1860 | raw_spin_lock_irqsave(&rp->lock, flags); | |
1861 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
1862 | raw_spin_unlock_irqrestore(&rp->lock, flags); | |
f47cd9b5 | 1863 | return 0; |
55ca6140 | 1864 | } |
f47cd9b5 | 1865 | |
4c4308cb CH |
1866 | arch_prepare_kretprobe(ri, regs); |
1867 | ||
1868 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1869 | INIT_HLIST_NODE(&ri->hlist); |
1870 | kretprobe_table_lock(hash, &flags); | |
1871 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1872 | kretprobe_table_unlock(hash, &flags); | |
1873 | } else { | |
4c4308cb | 1874 | rp->nmissed++; |
ec484608 | 1875 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1876 | } |
e65cefe8 AB |
1877 | return 0; |
1878 | } | |
820aede0 | 1879 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
e65cefe8 | 1880 | |
55479f64 | 1881 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1882 | { |
1883 | int ret = 0; | |
1884 | struct kretprobe_instance *inst; | |
1885 | int i; | |
b2a5cd69 | 1886 | void *addr; |
f438d914 MH |
1887 | |
1888 | if (kretprobe_blacklist_size) { | |
b2a5cd69 | 1889 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
1890 | if (IS_ERR(addr)) |
1891 | return PTR_ERR(addr); | |
f438d914 MH |
1892 | |
1893 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1894 | if (kretprobe_blacklist[i].addr == addr) | |
1895 | return -EINVAL; | |
1896 | } | |
1897 | } | |
b94cce92 HN |
1898 | |
1899 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1900 | rp->kp.post_handler = NULL; |
1901 | rp->kp.fault_handler = NULL; | |
1902 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1903 | |
1904 | /* Pre-allocate memory for max kretprobe instances */ | |
1905 | if (rp->maxactive <= 0) { | |
1906 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1907 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1908 | #else |
4dae560f | 1909 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1910 | #endif |
1911 | } | |
ec484608 | 1912 | raw_spin_lock_init(&rp->lock); |
b94cce92 HN |
1913 | INIT_HLIST_HEAD(&rp->free_instances); |
1914 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1915 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1916 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1917 | if (inst == NULL) { |
1918 | free_rp_inst(rp); | |
1919 | return -ENOMEM; | |
1920 | } | |
ef53d9c5 S |
1921 | INIT_HLIST_NODE(&inst->hlist); |
1922 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1923 | } |
1924 | ||
1925 | rp->nmissed = 0; | |
1926 | /* Establish function entry probe point */ | |
49ad2fd7 | 1927 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1928 | if (ret != 0) |
b94cce92 HN |
1929 | free_rp_inst(rp); |
1930 | return ret; | |
1931 | } | |
99081ab5 | 1932 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1933 | |
55479f64 | 1934 | int register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1935 | { |
1936 | int ret = 0, i; | |
1937 | ||
1938 | if (num <= 0) | |
1939 | return -EINVAL; | |
1940 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1941 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1942 | if (ret < 0) { |
1943 | if (i > 0) | |
1944 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1945 | break; |
1946 | } | |
1947 | } | |
1948 | return ret; | |
1949 | } | |
99081ab5 | 1950 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1951 | |
55479f64 | 1952 | void unregister_kretprobe(struct kretprobe *rp) |
4a296e07 MH |
1953 | { |
1954 | unregister_kretprobes(&rp, 1); | |
1955 | } | |
99081ab5 | 1956 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1957 | |
55479f64 | 1958 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1959 | { |
1960 | int i; | |
1961 | ||
1962 | if (num <= 0) | |
1963 | return; | |
1964 | mutex_lock(&kprobe_mutex); | |
1965 | for (i = 0; i < num; i++) | |
1966 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1967 | rps[i]->kp.addr = NULL; | |
1968 | mutex_unlock(&kprobe_mutex); | |
1969 | ||
1970 | synchronize_sched(); | |
1971 | for (i = 0; i < num; i++) { | |
1972 | if (rps[i]->kp.addr) { | |
1973 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1974 | cleanup_rp_inst(rps[i]); | |
1975 | } | |
1976 | } | |
1977 | } | |
99081ab5 | 1978 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 1979 | |
9edddaa2 | 1980 | #else /* CONFIG_KRETPROBES */ |
55479f64 | 1981 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1982 | { |
1983 | return -ENOSYS; | |
1984 | } | |
99081ab5 | 1985 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1986 | |
55479f64 | 1987 | int register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1988 | { |
4a296e07 | 1989 | return -ENOSYS; |
346fd59b | 1990 | } |
99081ab5 MH |
1991 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1992 | ||
55479f64 | 1993 | void unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1994 | { |
4a296e07 | 1995 | } |
99081ab5 | 1996 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 1997 | |
55479f64 | 1998 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1999 | { |
2000 | } | |
99081ab5 | 2001 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 2002 | |
820aede0 | 2003 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
4a296e07 MH |
2004 | { |
2005 | return 0; | |
b94cce92 | 2006 | } |
820aede0 | 2007 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
b94cce92 | 2008 | |
4a296e07 MH |
2009 | #endif /* CONFIG_KRETPROBES */ |
2010 | ||
e8386a0c | 2011 | /* Set the kprobe gone and remove its instruction buffer. */ |
55479f64 | 2012 | static void kill_kprobe(struct kprobe *p) |
e8386a0c MH |
2013 | { |
2014 | struct kprobe *kp; | |
de5bd88d | 2015 | |
e8386a0c | 2016 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 2017 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
2018 | /* |
2019 | * If this is an aggr_kprobe, we have to list all the | |
2020 | * chained probes and mark them GONE. | |
2021 | */ | |
2022 | list_for_each_entry_rcu(kp, &p->list, list) | |
2023 | kp->flags |= KPROBE_FLAG_GONE; | |
2024 | p->post_handler = NULL; | |
2025 | p->break_handler = NULL; | |
afd66255 | 2026 | kill_optimized_kprobe(p); |
e8386a0c MH |
2027 | } |
2028 | /* | |
2029 | * Here, we can remove insn_slot safely, because no thread calls | |
2030 | * the original probed function (which will be freed soon) any more. | |
2031 | */ | |
2032 | arch_remove_kprobe(p); | |
2033 | } | |
2034 | ||
c0614829 | 2035 | /* Disable one kprobe */ |
55479f64 | 2036 | int disable_kprobe(struct kprobe *kp) |
c0614829 MH |
2037 | { |
2038 | int ret = 0; | |
c0614829 MH |
2039 | |
2040 | mutex_lock(&kprobe_mutex); | |
2041 | ||
6f0f1dd7 MH |
2042 | /* Disable this kprobe */ |
2043 | if (__disable_kprobe(kp) == NULL) | |
c0614829 | 2044 | ret = -EINVAL; |
c0614829 | 2045 | |
c0614829 MH |
2046 | mutex_unlock(&kprobe_mutex); |
2047 | return ret; | |
2048 | } | |
2049 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
2050 | ||
2051 | /* Enable one kprobe */ | |
55479f64 | 2052 | int enable_kprobe(struct kprobe *kp) |
c0614829 MH |
2053 | { |
2054 | int ret = 0; | |
2055 | struct kprobe *p; | |
2056 | ||
2057 | mutex_lock(&kprobe_mutex); | |
2058 | ||
2059 | /* Check whether specified probe is valid. */ | |
2060 | p = __get_valid_kprobe(kp); | |
2061 | if (unlikely(p == NULL)) { | |
2062 | ret = -EINVAL; | |
2063 | goto out; | |
2064 | } | |
2065 | ||
2066 | if (kprobe_gone(kp)) { | |
2067 | /* This kprobe has gone, we couldn't enable it. */ | |
2068 | ret = -EINVAL; | |
2069 | goto out; | |
2070 | } | |
2071 | ||
2072 | if (p != kp) | |
2073 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
2074 | ||
2075 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
2076 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
2077 | arm_kprobe(p); | |
2078 | } | |
2079 | out: | |
2080 | mutex_unlock(&kprobe_mutex); | |
2081 | return ret; | |
2082 | } | |
2083 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
2084 | ||
820aede0 | 2085 | void dump_kprobe(struct kprobe *kp) |
24851d24 FW |
2086 | { |
2087 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
2088 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
2089 | kp->symbol_name, kp->addr, kp->offset); | |
2090 | } | |
820aede0 | 2091 | NOKPROBE_SYMBOL(dump_kprobe); |
24851d24 | 2092 | |
376e2424 MH |
2093 | /* |
2094 | * Lookup and populate the kprobe_blacklist. | |
2095 | * | |
2096 | * Unlike the kretprobe blacklist, we'll need to determine | |
2097 | * the range of addresses that belong to the said functions, | |
2098 | * since a kprobe need not necessarily be at the beginning | |
2099 | * of a function. | |
2100 | */ | |
2101 | static int __init populate_kprobe_blacklist(unsigned long *start, | |
2102 | unsigned long *end) | |
2103 | { | |
2104 | unsigned long *iter; | |
2105 | struct kprobe_blacklist_entry *ent; | |
d81b4253 | 2106 | unsigned long entry, offset = 0, size = 0; |
376e2424 MH |
2107 | |
2108 | for (iter = start; iter < end; iter++) { | |
d81b4253 MH |
2109 | entry = arch_deref_entry_point((void *)*iter); |
2110 | ||
2111 | if (!kernel_text_address(entry) || | |
2112 | !kallsyms_lookup_size_offset(entry, &size, &offset)) { | |
2113 | pr_err("Failed to find blacklist at %p\n", | |
2114 | (void *)entry); | |
376e2424 MH |
2115 | continue; |
2116 | } | |
2117 | ||
2118 | ent = kmalloc(sizeof(*ent), GFP_KERNEL); | |
2119 | if (!ent) | |
2120 | return -ENOMEM; | |
d81b4253 MH |
2121 | ent->start_addr = entry; |
2122 | ent->end_addr = entry + size; | |
376e2424 MH |
2123 | INIT_LIST_HEAD(&ent->list); |
2124 | list_add_tail(&ent->list, &kprobe_blacklist); | |
2125 | } | |
2126 | return 0; | |
2127 | } | |
2128 | ||
e8386a0c | 2129 | /* Module notifier call back, checking kprobes on the module */ |
55479f64 MH |
2130 | static int kprobes_module_callback(struct notifier_block *nb, |
2131 | unsigned long val, void *data) | |
e8386a0c MH |
2132 | { |
2133 | struct module *mod = data; | |
2134 | struct hlist_head *head; | |
e8386a0c MH |
2135 | struct kprobe *p; |
2136 | unsigned int i; | |
f24659d9 | 2137 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2138 | |
f24659d9 | 2139 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2140 | return NOTIFY_DONE; |
2141 | ||
2142 | /* | |
f24659d9 MH |
2143 | * When MODULE_STATE_GOING was notified, both of module .text and |
2144 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
2145 | * notified, only .init.text section would be freed. We need to | |
2146 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
2147 | */ |
2148 | mutex_lock(&kprobe_mutex); | |
2149 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2150 | head = &kprobe_table[i]; | |
b67bfe0d | 2151 | hlist_for_each_entry_rcu(p, head, hlist) |
f24659d9 MH |
2152 | if (within_module_init((unsigned long)p->addr, mod) || |
2153 | (checkcore && | |
2154 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2155 | /* |
2156 | * The vaddr this probe is installed will soon | |
2157 | * be vfreed buy not synced to disk. Hence, | |
2158 | * disarming the breakpoint isn't needed. | |
2159 | */ | |
2160 | kill_kprobe(p); | |
2161 | } | |
2162 | } | |
2163 | mutex_unlock(&kprobe_mutex); | |
2164 | return NOTIFY_DONE; | |
2165 | } | |
2166 | ||
2167 | static struct notifier_block kprobe_module_nb = { | |
2168 | .notifier_call = kprobes_module_callback, | |
2169 | .priority = 0 | |
2170 | }; | |
2171 | ||
376e2424 MH |
2172 | /* Markers of _kprobe_blacklist section */ |
2173 | extern unsigned long __start_kprobe_blacklist[]; | |
2174 | extern unsigned long __stop_kprobe_blacklist[]; | |
2175 | ||
1da177e4 LT |
2176 | static int __init init_kprobes(void) |
2177 | { | |
2178 | int i, err = 0; | |
2179 | ||
2180 | /* FIXME allocate the probe table, currently defined statically */ | |
2181 | /* initialize all list heads */ | |
b94cce92 | 2182 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 2183 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 2184 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ec484608 | 2185 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 2186 | } |
1da177e4 | 2187 | |
376e2424 MH |
2188 | err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
2189 | __stop_kprobe_blacklist); | |
2190 | if (err) { | |
2191 | pr_err("kprobes: failed to populate blacklist: %d\n", err); | |
2192 | pr_err("Please take care of using kprobes.\n"); | |
3d8d996e SD |
2193 | } |
2194 | ||
f438d914 MH |
2195 | if (kretprobe_blacklist_size) { |
2196 | /* lookup the function address from its name */ | |
2197 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
49e0b465 NR |
2198 | kretprobe_blacklist[i].addr = |
2199 | kprobe_lookup_name(kretprobe_blacklist[i].name); | |
f438d914 MH |
2200 | if (!kretprobe_blacklist[i].addr) |
2201 | printk("kretprobe: lookup failed: %s\n", | |
2202 | kretprobe_blacklist[i].name); | |
2203 | } | |
2204 | } | |
2205 | ||
b2be84df MH |
2206 | #if defined(CONFIG_OPTPROBES) |
2207 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) | |
afd66255 MH |
2208 | /* Init kprobe_optinsn_slots */ |
2209 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
2210 | #endif | |
b2be84df MH |
2211 | /* By default, kprobes can be optimized */ |
2212 | kprobes_allow_optimization = true; | |
2213 | #endif | |
afd66255 | 2214 | |
e579abeb MH |
2215 | /* By default, kprobes are armed */ |
2216 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2217 | |
6772926b | 2218 | err = arch_init_kprobes(); |
802eae7c RL |
2219 | if (!err) |
2220 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
2221 | if (!err) |
2222 | err = register_module_notifier(&kprobe_module_nb); | |
2223 | ||
ef53d9c5 | 2224 | kprobes_initialized = (err == 0); |
802eae7c | 2225 | |
8c1c9356 AM |
2226 | if (!err) |
2227 | init_test_probes(); | |
1da177e4 LT |
2228 | return err; |
2229 | } | |
2230 | ||
346fd59b | 2231 | #ifdef CONFIG_DEBUG_FS |
55479f64 | 2232 | static void report_probe(struct seq_file *pi, struct kprobe *p, |
afd66255 | 2233 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2234 | { |
2235 | char *kprobe_type; | |
2236 | ||
2237 | if (p->pre_handler == pre_handler_kretprobe) | |
2238 | kprobe_type = "r"; | |
2239 | else if (p->pre_handler == setjmp_pre_handler) | |
2240 | kprobe_type = "j"; | |
2241 | else | |
2242 | kprobe_type = "k"; | |
afd66255 | 2243 | |
346fd59b | 2244 | if (sym) |
afd66255 | 2245 | seq_printf(pi, "%p %s %s+0x%x %s ", |
de5bd88d | 2246 | p->addr, kprobe_type, sym, offset, |
afd66255 | 2247 | (modname ? modname : " ")); |
346fd59b | 2248 | else |
afd66255 MH |
2249 | seq_printf(pi, "%p %s %p ", |
2250 | p->addr, kprobe_type, p->addr); | |
2251 | ||
2252 | if (!pp) | |
2253 | pp = p; | |
ae6aa16f | 2254 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2255 | (kprobe_gone(p) ? "[GONE]" : ""), |
2256 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2257 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2258 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2259 | } |
2260 | ||
55479f64 | 2261 | static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
346fd59b SD |
2262 | { |
2263 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2264 | } | |
2265 | ||
55479f64 | 2266 | static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
346fd59b SD |
2267 | { |
2268 | (*pos)++; | |
2269 | if (*pos >= KPROBE_TABLE_SIZE) | |
2270 | return NULL; | |
2271 | return pos; | |
2272 | } | |
2273 | ||
55479f64 | 2274 | static void kprobe_seq_stop(struct seq_file *f, void *v) |
346fd59b SD |
2275 | { |
2276 | /* Nothing to do */ | |
2277 | } | |
2278 | ||
55479f64 | 2279 | static int show_kprobe_addr(struct seq_file *pi, void *v) |
346fd59b SD |
2280 | { |
2281 | struct hlist_head *head; | |
346fd59b SD |
2282 | struct kprobe *p, *kp; |
2283 | const char *sym = NULL; | |
2284 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 2285 | unsigned long offset = 0; |
ab767865 | 2286 | char *modname, namebuf[KSYM_NAME_LEN]; |
346fd59b SD |
2287 | |
2288 | head = &kprobe_table[i]; | |
2289 | preempt_disable(); | |
b67bfe0d | 2290 | hlist_for_each_entry_rcu(p, head, hlist) { |
ffb45122 | 2291 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2292 | &offset, &modname, namebuf); |
afd66255 | 2293 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2294 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2295 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2296 | } else |
afd66255 | 2297 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2298 | } |
2299 | preempt_enable(); | |
2300 | return 0; | |
2301 | } | |
2302 | ||
88e9d34c | 2303 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
2304 | .start = kprobe_seq_start, |
2305 | .next = kprobe_seq_next, | |
2306 | .stop = kprobe_seq_stop, | |
2307 | .show = show_kprobe_addr | |
2308 | }; | |
2309 | ||
55479f64 | 2310 | static int kprobes_open(struct inode *inode, struct file *filp) |
346fd59b SD |
2311 | { |
2312 | return seq_open(filp, &kprobes_seq_ops); | |
2313 | } | |
2314 | ||
828c0950 | 2315 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
2316 | .open = kprobes_open, |
2317 | .read = seq_read, | |
2318 | .llseek = seq_lseek, | |
2319 | .release = seq_release, | |
2320 | }; | |
2321 | ||
63724740 MH |
2322 | /* kprobes/blacklist -- shows which functions can not be probed */ |
2323 | static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) | |
2324 | { | |
2325 | return seq_list_start(&kprobe_blacklist, *pos); | |
2326 | } | |
2327 | ||
2328 | static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
2329 | { | |
2330 | return seq_list_next(v, &kprobe_blacklist, pos); | |
2331 | } | |
2332 | ||
2333 | static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) | |
2334 | { | |
2335 | struct kprobe_blacklist_entry *ent = | |
2336 | list_entry(v, struct kprobe_blacklist_entry, list); | |
2337 | ||
2338 | seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr, | |
2339 | (void *)ent->end_addr, (void *)ent->start_addr); | |
2340 | return 0; | |
2341 | } | |
2342 | ||
2343 | static const struct seq_operations kprobe_blacklist_seq_ops = { | |
2344 | .start = kprobe_blacklist_seq_start, | |
2345 | .next = kprobe_blacklist_seq_next, | |
2346 | .stop = kprobe_seq_stop, /* Reuse void function */ | |
2347 | .show = kprobe_blacklist_seq_show, | |
2348 | }; | |
2349 | ||
2350 | static int kprobe_blacklist_open(struct inode *inode, struct file *filp) | |
2351 | { | |
2352 | return seq_open(filp, &kprobe_blacklist_seq_ops); | |
2353 | } | |
2354 | ||
2355 | static const struct file_operations debugfs_kprobe_blacklist_ops = { | |
2356 | .open = kprobe_blacklist_open, | |
2357 | .read = seq_read, | |
2358 | .llseek = seq_lseek, | |
2359 | .release = seq_release, | |
2360 | }; | |
2361 | ||
55479f64 | 2362 | static void arm_all_kprobes(void) |
bf8f6e5b AM |
2363 | { |
2364 | struct hlist_head *head; | |
bf8f6e5b AM |
2365 | struct kprobe *p; |
2366 | unsigned int i; | |
2367 | ||
2368 | mutex_lock(&kprobe_mutex); | |
2369 | ||
e579abeb MH |
2370 | /* If kprobes are armed, just return */ |
2371 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2372 | goto already_enabled; |
2373 | ||
977ad481 WN |
2374 | /* |
2375 | * optimize_kprobe() called by arm_kprobe() checks | |
2376 | * kprobes_all_disarmed, so set kprobes_all_disarmed before | |
2377 | * arm_kprobe. | |
2378 | */ | |
2379 | kprobes_all_disarmed = false; | |
afd66255 | 2380 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2381 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2382 | head = &kprobe_table[i]; | |
b67bfe0d | 2383 | hlist_for_each_entry_rcu(p, head, hlist) |
de5bd88d | 2384 | if (!kprobe_disabled(p)) |
ae6aa16f | 2385 | arm_kprobe(p); |
bf8f6e5b AM |
2386 | } |
2387 | ||
bf8f6e5b AM |
2388 | printk(KERN_INFO "Kprobes globally enabled\n"); |
2389 | ||
2390 | already_enabled: | |
2391 | mutex_unlock(&kprobe_mutex); | |
2392 | return; | |
2393 | } | |
2394 | ||
55479f64 | 2395 | static void disarm_all_kprobes(void) |
bf8f6e5b AM |
2396 | { |
2397 | struct hlist_head *head; | |
bf8f6e5b AM |
2398 | struct kprobe *p; |
2399 | unsigned int i; | |
2400 | ||
2401 | mutex_lock(&kprobe_mutex); | |
2402 | ||
e579abeb | 2403 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2404 | if (kprobes_all_disarmed) { |
2405 | mutex_unlock(&kprobe_mutex); | |
2406 | return; | |
2407 | } | |
bf8f6e5b | 2408 | |
e579abeb | 2409 | kprobes_all_disarmed = true; |
bf8f6e5b | 2410 | printk(KERN_INFO "Kprobes globally disabled\n"); |
afd66255 | 2411 | |
bf8f6e5b AM |
2412 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2413 | head = &kprobe_table[i]; | |
b67bfe0d | 2414 | hlist_for_each_entry_rcu(p, head, hlist) { |
de5bd88d | 2415 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
ae6aa16f | 2416 | disarm_kprobe(p, false); |
bf8f6e5b AM |
2417 | } |
2418 | } | |
bf8f6e5b | 2419 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2420 | |
6274de49 MH |
2421 | /* Wait for disarming all kprobes by optimizer */ |
2422 | wait_for_kprobe_optimizer(); | |
bf8f6e5b AM |
2423 | } |
2424 | ||
2425 | /* | |
2426 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2427 | * when the bool state is switched. We can reuse that facility when | |
2428 | * available | |
2429 | */ | |
2430 | static ssize_t read_enabled_file_bool(struct file *file, | |
2431 | char __user *user_buf, size_t count, loff_t *ppos) | |
2432 | { | |
2433 | char buf[3]; | |
2434 | ||
e579abeb | 2435 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
2436 | buf[0] = '1'; |
2437 | else | |
2438 | buf[0] = '0'; | |
2439 | buf[1] = '\n'; | |
2440 | buf[2] = 0x00; | |
2441 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2442 | } | |
2443 | ||
2444 | static ssize_t write_enabled_file_bool(struct file *file, | |
2445 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2446 | { | |
2447 | char buf[32]; | |
efeb156e | 2448 | size_t buf_size; |
bf8f6e5b AM |
2449 | |
2450 | buf_size = min(count, (sizeof(buf)-1)); | |
2451 | if (copy_from_user(buf, user_buf, buf_size)) | |
2452 | return -EFAULT; | |
2453 | ||
10fb46d5 | 2454 | buf[buf_size] = '\0'; |
bf8f6e5b AM |
2455 | switch (buf[0]) { |
2456 | case 'y': | |
2457 | case 'Y': | |
2458 | case '1': | |
e579abeb | 2459 | arm_all_kprobes(); |
bf8f6e5b AM |
2460 | break; |
2461 | case 'n': | |
2462 | case 'N': | |
2463 | case '0': | |
e579abeb | 2464 | disarm_all_kprobes(); |
bf8f6e5b | 2465 | break; |
10fb46d5 MK |
2466 | default: |
2467 | return -EINVAL; | |
bf8f6e5b AM |
2468 | } |
2469 | ||
2470 | return count; | |
2471 | } | |
2472 | ||
828c0950 | 2473 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2474 | .read = read_enabled_file_bool, |
2475 | .write = write_enabled_file_bool, | |
6038f373 | 2476 | .llseek = default_llseek, |
bf8f6e5b AM |
2477 | }; |
2478 | ||
55479f64 | 2479 | static int __init debugfs_kprobe_init(void) |
346fd59b SD |
2480 | { |
2481 | struct dentry *dir, *file; | |
bf8f6e5b | 2482 | unsigned int value = 1; |
346fd59b SD |
2483 | |
2484 | dir = debugfs_create_dir("kprobes", NULL); | |
2485 | if (!dir) | |
2486 | return -ENOMEM; | |
2487 | ||
e3869792 | 2488 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b | 2489 | &debugfs_kprobes_operations); |
63724740 MH |
2490 | if (!file) |
2491 | goto error; | |
346fd59b | 2492 | |
bf8f6e5b AM |
2493 | file = debugfs_create_file("enabled", 0600, dir, |
2494 | &value, &fops_kp); | |
63724740 MH |
2495 | if (!file) |
2496 | goto error; | |
2497 | ||
2498 | file = debugfs_create_file("blacklist", 0444, dir, NULL, | |
2499 | &debugfs_kprobe_blacklist_ops); | |
2500 | if (!file) | |
2501 | goto error; | |
bf8f6e5b | 2502 | |
346fd59b | 2503 | return 0; |
63724740 MH |
2504 | |
2505 | error: | |
2506 | debugfs_remove(dir); | |
2507 | return -ENOMEM; | |
346fd59b SD |
2508 | } |
2509 | ||
2510 | late_initcall(debugfs_kprobe_init); | |
2511 | #endif /* CONFIG_DEBUG_FS */ | |
2512 | ||
2513 | module_init(init_kprobes); | |
1da177e4 | 2514 | |
99081ab5 | 2515 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 2516 | EXPORT_SYMBOL_GPL(jprobe_return); |