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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 AM |
60 | |
61 | /* | |
62 | * Some oddball architectures like 64bit powerpc have function descriptors | |
63 | * so this must be overridable. | |
64 | */ | |
65 | #ifndef kprobe_lookup_name | |
66 | #define kprobe_lookup_name(name, addr) \ | |
67 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) | |
68 | #endif | |
69 | ||
ef53d9c5 | 70 | static int kprobes_initialized; |
1da177e4 | 71 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 72 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 73 | |
bf8f6e5b | 74 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 75 | static bool kprobes_all_disarmed; |
bf8f6e5b | 76 | |
43948f50 MH |
77 | /* This protects kprobe_table and optimizing_list */ |
78 | static DEFINE_MUTEX(kprobe_mutex); | |
e6584523 | 79 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 80 | static struct { |
ec484608 | 81 | raw_spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
82 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
83 | ||
ec484608 | 84 | static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
ef53d9c5 S |
85 | { |
86 | return &(kretprobe_table_locks[hash].lock); | |
87 | } | |
1da177e4 | 88 | |
376e2424 MH |
89 | /* Blacklist -- list of struct kprobe_blacklist_entry */ |
90 | static LIST_HEAD(kprobe_blacklist); | |
3d8d996e | 91 | |
2d14e39d | 92 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
93 | /* |
94 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
95 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
96 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
97 | * is a recipe for disaster | |
98 | */ | |
9ec4b1f3 | 99 | struct kprobe_insn_page { |
c5cb5a2d | 100 | struct list_head list; |
9ec4b1f3 | 101 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
af96397d | 102 | struct kprobe_insn_cache *cache; |
9ec4b1f3 | 103 | int nused; |
b4c6c34a | 104 | int ngarbage; |
4610ee1d | 105 | char slot_used[]; |
9ec4b1f3 AM |
106 | }; |
107 | ||
4610ee1d MH |
108 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
109 | (offsetof(struct kprobe_insn_page, slot_used) + \ | |
110 | (sizeof(char) * (slots))) | |
111 | ||
4610ee1d MH |
112 | static int slots_per_page(struct kprobe_insn_cache *c) |
113 | { | |
114 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
115 | } | |
116 | ||
ab40c5c6 MH |
117 | enum kprobe_slot_state { |
118 | SLOT_CLEAN = 0, | |
119 | SLOT_DIRTY = 1, | |
120 | SLOT_USED = 2, | |
121 | }; | |
122 | ||
af96397d HC |
123 | static void *alloc_insn_page(void) |
124 | { | |
125 | return module_alloc(PAGE_SIZE); | |
126 | } | |
127 | ||
128 | static void free_insn_page(void *page) | |
129 | { | |
be1f221c | 130 | module_memfree(page); |
af96397d HC |
131 | } |
132 | ||
c802d64a HC |
133 | struct kprobe_insn_cache kprobe_insn_slots = { |
134 | .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), | |
af96397d HC |
135 | .alloc = alloc_insn_page, |
136 | .free = free_insn_page, | |
4610ee1d MH |
137 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
138 | .insn_size = MAX_INSN_SIZE, | |
139 | .nr_garbage = 0, | |
140 | }; | |
55479f64 | 141 | static int collect_garbage_slots(struct kprobe_insn_cache *c); |
b4c6c34a | 142 | |
9ec4b1f3 | 143 | /** |
12941560 | 144 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
145 | * We allocate an executable page if there's no room on existing ones. |
146 | */ | |
55479f64 | 147 | kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
148 | { |
149 | struct kprobe_insn_page *kip; | |
c802d64a | 150 | kprobe_opcode_t *slot = NULL; |
9ec4b1f3 | 151 | |
5b485629 | 152 | /* Since the slot array is not protected by rcu, we need a mutex */ |
c802d64a | 153 | mutex_lock(&c->mutex); |
6f716acd | 154 | retry: |
5b485629 MH |
155 | rcu_read_lock(); |
156 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
4610ee1d | 157 | if (kip->nused < slots_per_page(c)) { |
9ec4b1f3 | 158 | int i; |
4610ee1d | 159 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
160 | if (kip->slot_used[i] == SLOT_CLEAN) { |
161 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 162 | kip->nused++; |
c802d64a | 163 | slot = kip->insns + (i * c->insn_size); |
5b485629 | 164 | rcu_read_unlock(); |
c802d64a | 165 | goto out; |
9ec4b1f3 AM |
166 | } |
167 | } | |
4610ee1d MH |
168 | /* kip->nused is broken. Fix it. */ |
169 | kip->nused = slots_per_page(c); | |
170 | WARN_ON(1); | |
9ec4b1f3 AM |
171 | } |
172 | } | |
5b485629 | 173 | rcu_read_unlock(); |
9ec4b1f3 | 174 | |
b4c6c34a | 175 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 176 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 177 | goto retry; |
4610ee1d MH |
178 | |
179 | /* All out of space. Need to allocate a new page. */ | |
180 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); | |
6f716acd | 181 | if (!kip) |
c802d64a | 182 | goto out; |
9ec4b1f3 AM |
183 | |
184 | /* | |
185 | * Use module_alloc so this page is within +/- 2GB of where the | |
186 | * kernel image and loaded module images reside. This is required | |
187 | * so x86_64 can correctly handle the %rip-relative fixups. | |
188 | */ | |
af96397d | 189 | kip->insns = c->alloc(); |
9ec4b1f3 AM |
190 | if (!kip->insns) { |
191 | kfree(kip); | |
c802d64a | 192 | goto out; |
9ec4b1f3 | 193 | } |
c5cb5a2d | 194 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 195 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 196 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 197 | kip->nused = 1; |
b4c6c34a | 198 | kip->ngarbage = 0; |
af96397d | 199 | kip->cache = c; |
5b485629 | 200 | list_add_rcu(&kip->list, &c->pages); |
c802d64a HC |
201 | slot = kip->insns; |
202 | out: | |
203 | mutex_unlock(&c->mutex); | |
204 | return slot; | |
12941560 MH |
205 | } |
206 | ||
b4c6c34a | 207 | /* Return 1 if all garbages are collected, otherwise 0. */ |
55479f64 | 208 | static int collect_one_slot(struct kprobe_insn_page *kip, int idx) |
b4c6c34a | 209 | { |
ab40c5c6 | 210 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
211 | kip->nused--; |
212 | if (kip->nused == 0) { | |
213 | /* | |
214 | * Page is no longer in use. Free it unless | |
215 | * it's the last one. We keep the last one | |
216 | * so as not to have to set it up again the | |
217 | * next time somebody inserts a probe. | |
218 | */ | |
4610ee1d | 219 | if (!list_is_singular(&kip->list)) { |
5b485629 MH |
220 | list_del_rcu(&kip->list); |
221 | synchronize_rcu(); | |
af96397d | 222 | kip->cache->free(kip->insns); |
b4c6c34a MH |
223 | kfree(kip); |
224 | } | |
225 | return 1; | |
226 | } | |
227 | return 0; | |
228 | } | |
229 | ||
55479f64 | 230 | static int collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 231 | { |
c5cb5a2d | 232 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 233 | |
615d0ebb MH |
234 | /* Ensure no-one is interrupted on the garbages */ |
235 | synchronize_sched(); | |
b4c6c34a | 236 | |
4610ee1d | 237 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 238 | int i; |
b4c6c34a MH |
239 | if (kip->ngarbage == 0) |
240 | continue; | |
241 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 242 | for (i = 0; i < slots_per_page(c); i++) { |
5b485629 | 243 | if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i)) |
b4c6c34a MH |
244 | break; |
245 | } | |
246 | } | |
4610ee1d | 247 | c->nr_garbage = 0; |
b4c6c34a MH |
248 | return 0; |
249 | } | |
250 | ||
55479f64 MH |
251 | void __free_insn_slot(struct kprobe_insn_cache *c, |
252 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
253 | { |
254 | struct kprobe_insn_page *kip; | |
5b485629 | 255 | long idx; |
9ec4b1f3 | 256 | |
c802d64a | 257 | mutex_lock(&c->mutex); |
5b485629 MH |
258 | rcu_read_lock(); |
259 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
260 | idx = ((long)slot - (long)kip->insns) / | |
261 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
262 | if (idx >= 0 && idx < slots_per_page(c)) | |
c802d64a | 263 | goto out; |
9ec4b1f3 | 264 | } |
5b485629 | 265 | /* Could not find this slot. */ |
4610ee1d | 266 | WARN_ON(1); |
5b485629 | 267 | kip = NULL; |
c802d64a | 268 | out: |
5b485629 MH |
269 | rcu_read_unlock(); |
270 | /* Mark and sweep: this may sleep */ | |
271 | if (kip) { | |
272 | /* Check double free */ | |
273 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
274 | if (dirty) { | |
275 | kip->slot_used[idx] = SLOT_DIRTY; | |
276 | kip->ngarbage++; | |
277 | if (++c->nr_garbage > slots_per_page(c)) | |
278 | collect_garbage_slots(c); | |
279 | } else { | |
280 | collect_one_slot(kip, idx); | |
281 | } | |
282 | } | |
c802d64a | 283 | mutex_unlock(&c->mutex); |
4610ee1d | 284 | } |
6f716acd | 285 | |
5b485629 MH |
286 | /* |
287 | * Check given address is on the page of kprobe instruction slots. | |
288 | * This will be used for checking whether the address on a stack | |
289 | * is on a text area or not. | |
290 | */ | |
291 | bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr) | |
292 | { | |
293 | struct kprobe_insn_page *kip; | |
294 | bool ret = false; | |
295 | ||
296 | rcu_read_lock(); | |
297 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
298 | if (addr >= (unsigned long)kip->insns && | |
299 | addr < (unsigned long)kip->insns + PAGE_SIZE) { | |
300 | ret = true; | |
301 | break; | |
302 | } | |
303 | } | |
304 | rcu_read_unlock(); | |
305 | ||
306 | return ret; | |
307 | } | |
308 | ||
afd66255 MH |
309 | #ifdef CONFIG_OPTPROBES |
310 | /* For optimized_kprobe buffer */ | |
c802d64a HC |
311 | struct kprobe_insn_cache kprobe_optinsn_slots = { |
312 | .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), | |
af96397d HC |
313 | .alloc = alloc_insn_page, |
314 | .free = free_insn_page, | |
afd66255 MH |
315 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
316 | /* .insn_size is initialized later */ | |
317 | .nr_garbage = 0, | |
318 | }; | |
afd66255 | 319 | #endif |
2d14e39d | 320 | #endif |
9ec4b1f3 | 321 | |
e6584523 AM |
322 | /* We have preemption disabled.. so it is safe to use __ versions */ |
323 | static inline void set_kprobe_instance(struct kprobe *kp) | |
324 | { | |
b76834bc | 325 | __this_cpu_write(kprobe_instance, kp); |
e6584523 AM |
326 | } |
327 | ||
328 | static inline void reset_kprobe_instance(void) | |
329 | { | |
b76834bc | 330 | __this_cpu_write(kprobe_instance, NULL); |
e6584523 AM |
331 | } |
332 | ||
3516a460 AM |
333 | /* |
334 | * This routine is called either: | |
49a2a1b8 | 335 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 336 | * OR |
d217d545 | 337 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 338 | */ |
820aede0 | 339 | struct kprobe *get_kprobe(void *addr) |
1da177e4 LT |
340 | { |
341 | struct hlist_head *head; | |
3516a460 | 342 | struct kprobe *p; |
1da177e4 LT |
343 | |
344 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
b67bfe0d | 345 | hlist_for_each_entry_rcu(p, head, hlist) { |
1da177e4 LT |
346 | if (p->addr == addr) |
347 | return p; | |
348 | } | |
afd66255 | 349 | |
1da177e4 LT |
350 | return NULL; |
351 | } | |
820aede0 | 352 | NOKPROBE_SYMBOL(get_kprobe); |
1da177e4 | 353 | |
820aede0 | 354 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
afd66255 MH |
355 | |
356 | /* Return true if the kprobe is an aggregator */ | |
357 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
358 | { | |
359 | return p->pre_handler == aggr_pre_handler; | |
360 | } | |
361 | ||
6274de49 MH |
362 | /* Return true(!0) if the kprobe is unused */ |
363 | static inline int kprobe_unused(struct kprobe *p) | |
364 | { | |
365 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && | |
366 | list_empty(&p->list); | |
367 | } | |
368 | ||
afd66255 MH |
369 | /* |
370 | * Keep all fields in the kprobe consistent | |
371 | */ | |
6d8e40a8 | 372 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 373 | { |
6d8e40a8 MH |
374 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
375 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
376 | } |
377 | ||
378 | #ifdef CONFIG_OPTPROBES | |
b2be84df MH |
379 | /* NOTE: change this value only with kprobe_mutex held */ |
380 | static bool kprobes_allow_optimization; | |
381 | ||
afd66255 MH |
382 | /* |
383 | * Call all pre_handler on the list, but ignores its return value. | |
384 | * This must be called from arch-dep optimized caller. | |
385 | */ | |
820aede0 | 386 | void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
afd66255 MH |
387 | { |
388 | struct kprobe *kp; | |
389 | ||
390 | list_for_each_entry_rcu(kp, &p->list, list) { | |
391 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
392 | set_kprobe_instance(kp); | |
393 | kp->pre_handler(kp, regs); | |
394 | } | |
395 | reset_kprobe_instance(); | |
396 | } | |
397 | } | |
820aede0 | 398 | NOKPROBE_SYMBOL(opt_pre_handler); |
afd66255 | 399 | |
6274de49 | 400 | /* Free optimized instructions and optimized_kprobe */ |
55479f64 | 401 | static void free_aggr_kprobe(struct kprobe *p) |
6274de49 MH |
402 | { |
403 | struct optimized_kprobe *op; | |
404 | ||
405 | op = container_of(p, struct optimized_kprobe, kp); | |
406 | arch_remove_optimized_kprobe(op); | |
407 | arch_remove_kprobe(p); | |
408 | kfree(op); | |
409 | } | |
410 | ||
afd66255 MH |
411 | /* Return true(!0) if the kprobe is ready for optimization. */ |
412 | static inline int kprobe_optready(struct kprobe *p) | |
413 | { | |
414 | struct optimized_kprobe *op; | |
415 | ||
416 | if (kprobe_aggrprobe(p)) { | |
417 | op = container_of(p, struct optimized_kprobe, kp); | |
418 | return arch_prepared_optinsn(&op->optinsn); | |
419 | } | |
420 | ||
421 | return 0; | |
422 | } | |
423 | ||
6274de49 MH |
424 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
425 | static inline int kprobe_disarmed(struct kprobe *p) | |
426 | { | |
427 | struct optimized_kprobe *op; | |
428 | ||
429 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ | |
430 | if (!kprobe_aggrprobe(p)) | |
431 | return kprobe_disabled(p); | |
432 | ||
433 | op = container_of(p, struct optimized_kprobe, kp); | |
434 | ||
435 | return kprobe_disabled(p) && list_empty(&op->list); | |
436 | } | |
437 | ||
438 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ | |
55479f64 | 439 | static int kprobe_queued(struct kprobe *p) |
6274de49 MH |
440 | { |
441 | struct optimized_kprobe *op; | |
442 | ||
443 | if (kprobe_aggrprobe(p)) { | |
444 | op = container_of(p, struct optimized_kprobe, kp); | |
445 | if (!list_empty(&op->list)) | |
446 | return 1; | |
447 | } | |
448 | return 0; | |
449 | } | |
450 | ||
afd66255 MH |
451 | /* |
452 | * Return an optimized kprobe whose optimizing code replaces | |
453 | * instructions including addr (exclude breakpoint). | |
454 | */ | |
55479f64 | 455 | static struct kprobe *get_optimized_kprobe(unsigned long addr) |
afd66255 MH |
456 | { |
457 | int i; | |
458 | struct kprobe *p = NULL; | |
459 | struct optimized_kprobe *op; | |
460 | ||
461 | /* Don't check i == 0, since that is a breakpoint case. */ | |
462 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
463 | p = get_kprobe((void *)(addr - i)); | |
464 | ||
465 | if (p && kprobe_optready(p)) { | |
466 | op = container_of(p, struct optimized_kprobe, kp); | |
467 | if (arch_within_optimized_kprobe(op, addr)) | |
468 | return p; | |
469 | } | |
470 | ||
471 | return NULL; | |
472 | } | |
473 | ||
474 | /* Optimization staging list, protected by kprobe_mutex */ | |
475 | static LIST_HEAD(optimizing_list); | |
6274de49 | 476 | static LIST_HEAD(unoptimizing_list); |
7b959fc5 | 477 | static LIST_HEAD(freeing_list); |
afd66255 MH |
478 | |
479 | static void kprobe_optimizer(struct work_struct *work); | |
480 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
481 | #define OPTIMIZE_DELAY 5 | |
482 | ||
61f4e13f MH |
483 | /* |
484 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
485 | * optimizing_list. | |
486 | */ | |
55479f64 | 487 | static void do_optimize_kprobes(void) |
afd66255 | 488 | { |
6274de49 MH |
489 | /* Optimization never be done when disarmed */ |
490 | if (kprobes_all_disarmed || !kprobes_allow_optimization || | |
491 | list_empty(&optimizing_list)) | |
492 | return; | |
493 | ||
afd66255 MH |
494 | /* |
495 | * The optimization/unoptimization refers online_cpus via | |
496 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
497 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
498 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
499 | * text_mutex but stop_machine can not be done because online_cpus | |
500 | * has been changed) | |
501 | * To avoid this deadlock, we need to call get_online_cpus() | |
502 | * for preventing cpu-hotplug outside of text_mutex locking. | |
503 | */ | |
504 | get_online_cpus(); | |
505 | mutex_lock(&text_mutex); | |
cd7ebe22 | 506 | arch_optimize_kprobes(&optimizing_list); |
afd66255 MH |
507 | mutex_unlock(&text_mutex); |
508 | put_online_cpus(); | |
61f4e13f MH |
509 | } |
510 | ||
6274de49 MH |
511 | /* |
512 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint | |
513 | * if need) kprobes listed on unoptimizing_list. | |
514 | */ | |
55479f64 | 515 | static void do_unoptimize_kprobes(void) |
6274de49 MH |
516 | { |
517 | struct optimized_kprobe *op, *tmp; | |
518 | ||
519 | /* Unoptimization must be done anytime */ | |
520 | if (list_empty(&unoptimizing_list)) | |
521 | return; | |
522 | ||
523 | /* Ditto to do_optimize_kprobes */ | |
524 | get_online_cpus(); | |
525 | mutex_lock(&text_mutex); | |
7b959fc5 | 526 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
f984ba4e | 527 | /* Loop free_list for disarming */ |
7b959fc5 | 528 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 MH |
529 | /* Disarm probes if marked disabled */ |
530 | if (kprobe_disabled(&op->kp)) | |
531 | arch_disarm_kprobe(&op->kp); | |
532 | if (kprobe_unused(&op->kp)) { | |
533 | /* | |
534 | * Remove unused probes from hash list. After waiting | |
535 | * for synchronization, these probes are reclaimed. | |
536 | * (reclaiming is done by do_free_cleaned_kprobes.) | |
537 | */ | |
538 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
539 | } else |
540 | list_del_init(&op->list); | |
541 | } | |
542 | mutex_unlock(&text_mutex); | |
543 | put_online_cpus(); | |
544 | } | |
545 | ||
546 | /* Reclaim all kprobes on the free_list */ | |
55479f64 | 547 | static void do_free_cleaned_kprobes(void) |
6274de49 MH |
548 | { |
549 | struct optimized_kprobe *op, *tmp; | |
550 | ||
7b959fc5 | 551 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 MH |
552 | BUG_ON(!kprobe_unused(&op->kp)); |
553 | list_del_init(&op->list); | |
554 | free_aggr_kprobe(&op->kp); | |
555 | } | |
556 | } | |
557 | ||
558 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
55479f64 | 559 | static void kick_kprobe_optimizer(void) |
6274de49 | 560 | { |
ad72b3be | 561 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de49 MH |
562 | } |
563 | ||
61f4e13f | 564 | /* Kprobe jump optimizer */ |
55479f64 | 565 | static void kprobe_optimizer(struct work_struct *work) |
61f4e13f | 566 | { |
72ef3794 | 567 | mutex_lock(&kprobe_mutex); |
61f4e13f MH |
568 | /* Lock modules while optimizing kprobes */ |
569 | mutex_lock(&module_mutex); | |
61f4e13f MH |
570 | |
571 | /* | |
6274de49 MH |
572 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
573 | * kprobes before waiting for quiesence period. | |
574 | */ | |
7b959fc5 | 575 | do_unoptimize_kprobes(); |
6274de49 MH |
576 | |
577 | /* | |
578 | * Step 2: Wait for quiesence period to ensure all running interrupts | |
61f4e13f MH |
579 | * are done. Because optprobe may modify multiple instructions |
580 | * there is a chance that Nth instruction is interrupted. In that | |
581 | * case, running interrupt can return to 2nd-Nth byte of jump | |
582 | * instruction. This wait is for avoiding it. | |
583 | */ | |
584 | synchronize_sched(); | |
585 | ||
6274de49 | 586 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 587 | do_optimize_kprobes(); |
6274de49 MH |
588 | |
589 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
7b959fc5 | 590 | do_free_cleaned_kprobes(); |
6274de49 | 591 | |
afd66255 | 592 | mutex_unlock(&module_mutex); |
72ef3794 | 593 | mutex_unlock(&kprobe_mutex); |
6274de49 | 594 | |
cd7ebe22 | 595 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 596 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 | 597 | kick_kprobe_optimizer(); |
6274de49 MH |
598 | } |
599 | ||
600 | /* Wait for completing optimization and unoptimization */ | |
55479f64 | 601 | static void wait_for_kprobe_optimizer(void) |
6274de49 | 602 | { |
ad72b3be TH |
603 | mutex_lock(&kprobe_mutex); |
604 | ||
605 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { | |
606 | mutex_unlock(&kprobe_mutex); | |
607 | ||
608 | /* this will also make optimizing_work execute immmediately */ | |
609 | flush_delayed_work(&optimizing_work); | |
610 | /* @optimizing_work might not have been queued yet, relax */ | |
611 | cpu_relax(); | |
612 | ||
613 | mutex_lock(&kprobe_mutex); | |
614 | } | |
615 | ||
616 | mutex_unlock(&kprobe_mutex); | |
afd66255 MH |
617 | } |
618 | ||
619 | /* Optimize kprobe if p is ready to be optimized */ | |
55479f64 | 620 | static void optimize_kprobe(struct kprobe *p) |
afd66255 MH |
621 | { |
622 | struct optimized_kprobe *op; | |
623 | ||
624 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 625 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
626 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
627 | return; | |
628 | ||
629 | /* Both of break_handler and post_handler are not supported. */ | |
630 | if (p->break_handler || p->post_handler) | |
631 | return; | |
632 | ||
633 | op = container_of(p, struct optimized_kprobe, kp); | |
634 | ||
635 | /* Check there is no other kprobes at the optimized instructions */ | |
636 | if (arch_check_optimized_kprobe(op) < 0) | |
637 | return; | |
638 | ||
639 | /* Check if it is already optimized. */ | |
640 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) | |
641 | return; | |
afd66255 | 642 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 MH |
643 | |
644 | if (!list_empty(&op->list)) | |
645 | /* This is under unoptimizing. Just dequeue the probe */ | |
646 | list_del_init(&op->list); | |
647 | else { | |
648 | list_add(&op->list, &optimizing_list); | |
649 | kick_kprobe_optimizer(); | |
650 | } | |
651 | } | |
652 | ||
653 | /* Short cut to direct unoptimizing */ | |
55479f64 | 654 | static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
6274de49 MH |
655 | { |
656 | get_online_cpus(); | |
657 | arch_unoptimize_kprobe(op); | |
658 | put_online_cpus(); | |
659 | if (kprobe_disabled(&op->kp)) | |
660 | arch_disarm_kprobe(&op->kp); | |
afd66255 MH |
661 | } |
662 | ||
663 | /* Unoptimize a kprobe if p is optimized */ | |
55479f64 | 664 | static void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
665 | { |
666 | struct optimized_kprobe *op; | |
667 | ||
6274de49 MH |
668 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
669 | return; /* This is not an optprobe nor optimized */ | |
670 | ||
671 | op = container_of(p, struct optimized_kprobe, kp); | |
672 | if (!kprobe_optimized(p)) { | |
673 | /* Unoptimized or unoptimizing case */ | |
674 | if (force && !list_empty(&op->list)) { | |
675 | /* | |
676 | * Only if this is unoptimizing kprobe and forced, | |
677 | * forcibly unoptimize it. (No need to unoptimize | |
678 | * unoptimized kprobe again :) | |
679 | */ | |
afd66255 | 680 | list_del_init(&op->list); |
6274de49 MH |
681 | force_unoptimize_kprobe(op); |
682 | } | |
683 | return; | |
684 | } | |
685 | ||
686 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
687 | if (!list_empty(&op->list)) { | |
688 | /* Dequeue from the optimization queue */ | |
689 | list_del_init(&op->list); | |
690 | return; | |
691 | } | |
692 | /* Optimized kprobe case */ | |
693 | if (force) | |
694 | /* Forcibly update the code: this is a special case */ | |
695 | force_unoptimize_kprobe(op); | |
696 | else { | |
697 | list_add(&op->list, &unoptimizing_list); | |
698 | kick_kprobe_optimizer(); | |
afd66255 MH |
699 | } |
700 | } | |
701 | ||
0490cd1f MH |
702 | /* Cancel unoptimizing for reusing */ |
703 | static void reuse_unused_kprobe(struct kprobe *ap) | |
704 | { | |
705 | struct optimized_kprobe *op; | |
706 | ||
707 | BUG_ON(!kprobe_unused(ap)); | |
708 | /* | |
709 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
710 | * there is still a relative jump) and disabled. | |
711 | */ | |
712 | op = container_of(ap, struct optimized_kprobe, kp); | |
713 | if (unlikely(list_empty(&op->list))) | |
714 | printk(KERN_WARNING "Warning: found a stray unused " | |
715 | "aggrprobe@%p\n", ap->addr); | |
716 | /* Enable the probe again */ | |
717 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
718 | /* Optimize it again (remove from op->list) */ | |
719 | BUG_ON(!kprobe_optready(ap)); | |
720 | optimize_kprobe(ap); | |
721 | } | |
722 | ||
afd66255 | 723 | /* Remove optimized instructions */ |
55479f64 | 724 | static void kill_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
725 | { |
726 | struct optimized_kprobe *op; | |
727 | ||
728 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
729 | if (!list_empty(&op->list)) |
730 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 731 | list_del_init(&op->list); |
6274de49 | 732 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc5 MH |
733 | |
734 | if (kprobe_unused(p)) { | |
735 | /* Enqueue if it is unused */ | |
736 | list_add(&op->list, &freeing_list); | |
737 | /* | |
738 | * Remove unused probes from the hash list. After waiting | |
739 | * for synchronization, this probe is reclaimed. | |
740 | * (reclaiming is done by do_free_cleaned_kprobes().) | |
741 | */ | |
742 | hlist_del_rcu(&op->kp.hlist); | |
743 | } | |
744 | ||
6274de49 | 745 | /* Don't touch the code, because it is already freed. */ |
afd66255 MH |
746 | arch_remove_optimized_kprobe(op); |
747 | } | |
748 | ||
749 | /* Try to prepare optimized instructions */ | |
55479f64 | 750 | static void prepare_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
751 | { |
752 | struct optimized_kprobe *op; | |
753 | ||
754 | op = container_of(p, struct optimized_kprobe, kp); | |
cbf6ab52 | 755 | arch_prepare_optimized_kprobe(op, p); |
afd66255 MH |
756 | } |
757 | ||
afd66255 | 758 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
55479f64 | 759 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
760 | { |
761 | struct optimized_kprobe *op; | |
762 | ||
763 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
764 | if (!op) | |
765 | return NULL; | |
766 | ||
767 | INIT_LIST_HEAD(&op->list); | |
768 | op->kp.addr = p->addr; | |
cbf6ab52 | 769 | arch_prepare_optimized_kprobe(op, p); |
afd66255 MH |
770 | |
771 | return &op->kp; | |
772 | } | |
773 | ||
55479f64 | 774 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
afd66255 MH |
775 | |
776 | /* | |
777 | * Prepare an optimized_kprobe and optimize it | |
778 | * NOTE: p must be a normal registered kprobe | |
779 | */ | |
55479f64 | 780 | static void try_to_optimize_kprobe(struct kprobe *p) |
afd66255 MH |
781 | { |
782 | struct kprobe *ap; | |
783 | struct optimized_kprobe *op; | |
784 | ||
ae6aa16f MH |
785 | /* Impossible to optimize ftrace-based kprobe */ |
786 | if (kprobe_ftrace(p)) | |
787 | return; | |
788 | ||
25764288 MH |
789 | /* For preparing optimization, jump_label_text_reserved() is called */ |
790 | jump_label_lock(); | |
791 | mutex_lock(&text_mutex); | |
792 | ||
afd66255 MH |
793 | ap = alloc_aggr_kprobe(p); |
794 | if (!ap) | |
25764288 | 795 | goto out; |
afd66255 MH |
796 | |
797 | op = container_of(ap, struct optimized_kprobe, kp); | |
798 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
799 | /* If failed to setup optimizing, fallback to kprobe */ | |
6274de49 MH |
800 | arch_remove_optimized_kprobe(op); |
801 | kfree(op); | |
25764288 | 802 | goto out; |
afd66255 MH |
803 | } |
804 | ||
805 | init_aggr_kprobe(ap, p); | |
25764288 MH |
806 | optimize_kprobe(ap); /* This just kicks optimizer thread */ |
807 | ||
808 | out: | |
809 | mutex_unlock(&text_mutex); | |
810 | jump_label_unlock(); | |
afd66255 MH |
811 | } |
812 | ||
b2be84df | 813 | #ifdef CONFIG_SYSCTL |
55479f64 | 814 | static void optimize_all_kprobes(void) |
b2be84df MH |
815 | { |
816 | struct hlist_head *head; | |
b2be84df MH |
817 | struct kprobe *p; |
818 | unsigned int i; | |
819 | ||
5c51543b | 820 | mutex_lock(&kprobe_mutex); |
b2be84df MH |
821 | /* If optimization is already allowed, just return */ |
822 | if (kprobes_allow_optimization) | |
5c51543b | 823 | goto out; |
b2be84df MH |
824 | |
825 | kprobes_allow_optimization = true; | |
b2be84df MH |
826 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
827 | head = &kprobe_table[i]; | |
b67bfe0d | 828 | hlist_for_each_entry_rcu(p, head, hlist) |
b2be84df MH |
829 | if (!kprobe_disabled(p)) |
830 | optimize_kprobe(p); | |
831 | } | |
b2be84df | 832 | printk(KERN_INFO "Kprobes globally optimized\n"); |
5c51543b MH |
833 | out: |
834 | mutex_unlock(&kprobe_mutex); | |
b2be84df MH |
835 | } |
836 | ||
55479f64 | 837 | static void unoptimize_all_kprobes(void) |
b2be84df MH |
838 | { |
839 | struct hlist_head *head; | |
b2be84df MH |
840 | struct kprobe *p; |
841 | unsigned int i; | |
842 | ||
5c51543b | 843 | mutex_lock(&kprobe_mutex); |
b2be84df | 844 | /* If optimization is already prohibited, just return */ |
5c51543b MH |
845 | if (!kprobes_allow_optimization) { |
846 | mutex_unlock(&kprobe_mutex); | |
b2be84df | 847 | return; |
5c51543b | 848 | } |
b2be84df MH |
849 | |
850 | kprobes_allow_optimization = false; | |
b2be84df MH |
851 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
852 | head = &kprobe_table[i]; | |
b67bfe0d | 853 | hlist_for_each_entry_rcu(p, head, hlist) { |
b2be84df | 854 | if (!kprobe_disabled(p)) |
6274de49 | 855 | unoptimize_kprobe(p, false); |
b2be84df MH |
856 | } |
857 | } | |
5c51543b MH |
858 | mutex_unlock(&kprobe_mutex); |
859 | ||
6274de49 MH |
860 | /* Wait for unoptimizing completion */ |
861 | wait_for_kprobe_optimizer(); | |
862 | printk(KERN_INFO "Kprobes globally unoptimized\n"); | |
b2be84df MH |
863 | } |
864 | ||
5c51543b | 865 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
b2be84df MH |
866 | int sysctl_kprobes_optimization; |
867 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, | |
868 | void __user *buffer, size_t *length, | |
869 | loff_t *ppos) | |
870 | { | |
871 | int ret; | |
872 | ||
5c51543b | 873 | mutex_lock(&kprobe_sysctl_mutex); |
b2be84df MH |
874 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
875 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
876 | ||
877 | if (sysctl_kprobes_optimization) | |
878 | optimize_all_kprobes(); | |
879 | else | |
880 | unoptimize_all_kprobes(); | |
5c51543b | 881 | mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df MH |
882 | |
883 | return ret; | |
884 | } | |
885 | #endif /* CONFIG_SYSCTL */ | |
886 | ||
6274de49 | 887 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
55479f64 | 888 | static void __arm_kprobe(struct kprobe *p) |
afd66255 | 889 | { |
6d8e40a8 | 890 | struct kprobe *_p; |
afd66255 MH |
891 | |
892 | /* Check collision with other optimized kprobes */ | |
6d8e40a8 MH |
893 | _p = get_optimized_kprobe((unsigned long)p->addr); |
894 | if (unlikely(_p)) | |
6274de49 MH |
895 | /* Fallback to unoptimized kprobe */ |
896 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
897 | |
898 | arch_arm_kprobe(p); | |
899 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
900 | } | |
901 | ||
6274de49 | 902 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
55479f64 | 903 | static void __disarm_kprobe(struct kprobe *p, bool reopt) |
afd66255 | 904 | { |
6d8e40a8 | 905 | struct kprobe *_p; |
afd66255 | 906 | |
69d54b91 WN |
907 | /* Try to unoptimize */ |
908 | unoptimize_kprobe(p, kprobes_all_disarmed); | |
afd66255 | 909 | |
6274de49 MH |
910 | if (!kprobe_queued(p)) { |
911 | arch_disarm_kprobe(p); | |
912 | /* If another kprobe was blocked, optimize it. */ | |
913 | _p = get_optimized_kprobe((unsigned long)p->addr); | |
914 | if (unlikely(_p) && reopt) | |
915 | optimize_kprobe(_p); | |
916 | } | |
917 | /* TODO: reoptimize others after unoptimized this probe */ | |
afd66255 MH |
918 | } |
919 | ||
920 | #else /* !CONFIG_OPTPROBES */ | |
921 | ||
922 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 923 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
924 | #define kill_optimized_kprobe(p) do {} while (0) |
925 | #define prepare_optimized_kprobe(p) do {} while (0) | |
926 | #define try_to_optimize_kprobe(p) do {} while (0) | |
927 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
928 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
929 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
930 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 931 | |
0490cd1f MH |
932 | /* There should be no unused kprobes can be reused without optimization */ |
933 | static void reuse_unused_kprobe(struct kprobe *ap) | |
934 | { | |
935 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); | |
936 | BUG_ON(kprobe_unused(ap)); | |
937 | } | |
938 | ||
55479f64 | 939 | static void free_aggr_kprobe(struct kprobe *p) |
afd66255 | 940 | { |
6274de49 | 941 | arch_remove_kprobe(p); |
afd66255 MH |
942 | kfree(p); |
943 | } | |
944 | ||
55479f64 | 945 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
946 | { |
947 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
948 | } | |
949 | #endif /* CONFIG_OPTPROBES */ | |
950 | ||
e7dbfe34 | 951 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 952 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
e5253896 | 953 | .func = kprobe_ftrace_handler, |
1d70be34 | 954 | .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
ae6aa16f MH |
955 | }; |
956 | static int kprobe_ftrace_enabled; | |
957 | ||
958 | /* Must ensure p->addr is really on ftrace */ | |
55479f64 | 959 | static int prepare_kprobe(struct kprobe *p) |
ae6aa16f MH |
960 | { |
961 | if (!kprobe_ftrace(p)) | |
962 | return arch_prepare_kprobe(p); | |
963 | ||
964 | return arch_prepare_kprobe_ftrace(p); | |
965 | } | |
966 | ||
967 | /* Caller must lock kprobe_mutex */ | |
55479f64 | 968 | static void arm_kprobe_ftrace(struct kprobe *p) |
ae6aa16f MH |
969 | { |
970 | int ret; | |
971 | ||
972 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
973 | (unsigned long)p->addr, 0, 0); | |
974 | WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
975 | kprobe_ftrace_enabled++; | |
976 | if (kprobe_ftrace_enabled == 1) { | |
977 | ret = register_ftrace_function(&kprobe_ftrace_ops); | |
978 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
979 | } | |
980 | } | |
981 | ||
982 | /* Caller must lock kprobe_mutex */ | |
55479f64 | 983 | static void disarm_kprobe_ftrace(struct kprobe *p) |
ae6aa16f MH |
984 | { |
985 | int ret; | |
986 | ||
987 | kprobe_ftrace_enabled--; | |
988 | if (kprobe_ftrace_enabled == 0) { | |
989 | ret = unregister_ftrace_function(&kprobe_ftrace_ops); | |
990 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
991 | } | |
992 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
993 | (unsigned long)p->addr, 1, 0); | |
994 | WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
995 | } | |
e7dbfe34 | 996 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
997 | #define prepare_kprobe(p) arch_prepare_kprobe(p) |
998 | #define arm_kprobe_ftrace(p) do {} while (0) | |
999 | #define disarm_kprobe_ftrace(p) do {} while (0) | |
1000 | #endif | |
1001 | ||
201517a7 | 1002 | /* Arm a kprobe with text_mutex */ |
55479f64 | 1003 | static void arm_kprobe(struct kprobe *kp) |
201517a7 | 1004 | { |
ae6aa16f MH |
1005 | if (unlikely(kprobe_ftrace(kp))) { |
1006 | arm_kprobe_ftrace(kp); | |
1007 | return; | |
1008 | } | |
afd66255 MH |
1009 | /* |
1010 | * Here, since __arm_kprobe() doesn't use stop_machine(), | |
1011 | * this doesn't cause deadlock on text_mutex. So, we don't | |
1012 | * need get_online_cpus(). | |
1013 | */ | |
201517a7 | 1014 | mutex_lock(&text_mutex); |
afd66255 | 1015 | __arm_kprobe(kp); |
201517a7 MH |
1016 | mutex_unlock(&text_mutex); |
1017 | } | |
1018 | ||
1019 | /* Disarm a kprobe with text_mutex */ | |
55479f64 | 1020 | static void disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 1021 | { |
ae6aa16f MH |
1022 | if (unlikely(kprobe_ftrace(kp))) { |
1023 | disarm_kprobe_ftrace(kp); | |
1024 | return; | |
1025 | } | |
6274de49 | 1026 | /* Ditto */ |
201517a7 | 1027 | mutex_lock(&text_mutex); |
ae6aa16f | 1028 | __disarm_kprobe(kp, reopt); |
201517a7 MH |
1029 | mutex_unlock(&text_mutex); |
1030 | } | |
1031 | ||
64f562c6 AM |
1032 | /* |
1033 | * Aggregate handlers for multiple kprobes support - these handlers | |
1034 | * take care of invoking the individual kprobe handlers on p->list | |
1035 | */ | |
820aede0 | 1036 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
1037 | { |
1038 | struct kprobe *kp; | |
1039 | ||
3516a460 | 1040 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1041 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1042 | set_kprobe_instance(kp); |
8b0914ea PP |
1043 | if (kp->pre_handler(kp, regs)) |
1044 | return 1; | |
64f562c6 | 1045 | } |
e6584523 | 1046 | reset_kprobe_instance(); |
64f562c6 AM |
1047 | } |
1048 | return 0; | |
1049 | } | |
820aede0 | 1050 | NOKPROBE_SYMBOL(aggr_pre_handler); |
64f562c6 | 1051 | |
820aede0 MH |
1052 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1053 | unsigned long flags) | |
64f562c6 AM |
1054 | { |
1055 | struct kprobe *kp; | |
1056 | ||
3516a460 | 1057 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1058 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1059 | set_kprobe_instance(kp); |
64f562c6 | 1060 | kp->post_handler(kp, regs, flags); |
e6584523 | 1061 | reset_kprobe_instance(); |
64f562c6 AM |
1062 | } |
1063 | } | |
64f562c6 | 1064 | } |
820aede0 | 1065 | NOKPROBE_SYMBOL(aggr_post_handler); |
64f562c6 | 1066 | |
820aede0 MH |
1067 | static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
1068 | int trapnr) | |
64f562c6 | 1069 | { |
b76834bc | 1070 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 | 1071 | |
64f562c6 AM |
1072 | /* |
1073 | * if we faulted "during" the execution of a user specified | |
1074 | * probe handler, invoke just that probe's fault handler | |
1075 | */ | |
e6584523 AM |
1076 | if (cur && cur->fault_handler) { |
1077 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
1078 | return 1; |
1079 | } | |
1080 | return 0; | |
1081 | } | |
820aede0 | 1082 | NOKPROBE_SYMBOL(aggr_fault_handler); |
64f562c6 | 1083 | |
820aede0 | 1084 | static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 1085 | { |
b76834bc | 1086 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 AM |
1087 | int ret = 0; |
1088 | ||
1089 | if (cur && cur->break_handler) { | |
1090 | if (cur->break_handler(cur, regs)) | |
1091 | ret = 1; | |
8b0914ea | 1092 | } |
e6584523 AM |
1093 | reset_kprobe_instance(); |
1094 | return ret; | |
8b0914ea | 1095 | } |
820aede0 | 1096 | NOKPROBE_SYMBOL(aggr_break_handler); |
8b0914ea | 1097 | |
bf8d5c52 | 1098 | /* Walks the list and increments nmissed count for multiprobe case */ |
820aede0 | 1099 | void kprobes_inc_nmissed_count(struct kprobe *p) |
bf8d5c52 KA |
1100 | { |
1101 | struct kprobe *kp; | |
afd66255 | 1102 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1103 | p->nmissed++; |
1104 | } else { | |
1105 | list_for_each_entry_rcu(kp, &p->list, list) | |
1106 | kp->nmissed++; | |
1107 | } | |
1108 | return; | |
1109 | } | |
820aede0 | 1110 | NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
bf8d5c52 | 1111 | |
820aede0 MH |
1112 | void recycle_rp_inst(struct kretprobe_instance *ri, |
1113 | struct hlist_head *head) | |
b94cce92 | 1114 | { |
ef53d9c5 S |
1115 | struct kretprobe *rp = ri->rp; |
1116 | ||
b94cce92 HN |
1117 | /* remove rp inst off the rprobe_inst_table */ |
1118 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
1119 | INIT_HLIST_NODE(&ri->hlist); |
1120 | if (likely(rp)) { | |
ec484608 | 1121 | raw_spin_lock(&rp->lock); |
ef53d9c5 | 1122 | hlist_add_head(&ri->hlist, &rp->free_instances); |
ec484608 | 1123 | raw_spin_unlock(&rp->lock); |
b94cce92 HN |
1124 | } else |
1125 | /* Unregistering */ | |
99219a3f | 1126 | hlist_add_head(&ri->hlist, head); |
b94cce92 | 1127 | } |
820aede0 | 1128 | NOKPROBE_SYMBOL(recycle_rp_inst); |
b94cce92 | 1129 | |
820aede0 | 1130 | void kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 | 1131 | struct hlist_head **head, unsigned long *flags) |
635c17c2 | 1132 | __acquires(hlist_lock) |
ef53d9c5 S |
1133 | { |
1134 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1135 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1136 | |
1137 | *head = &kretprobe_inst_table[hash]; | |
1138 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1139 | raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5 | 1140 | } |
820aede0 | 1141 | NOKPROBE_SYMBOL(kretprobe_hash_lock); |
ef53d9c5 | 1142 | |
820aede0 MH |
1143 | static void kretprobe_table_lock(unsigned long hash, |
1144 | unsigned long *flags) | |
635c17c2 | 1145 | __acquires(hlist_lock) |
b94cce92 | 1146 | { |
ec484608 TG |
1147 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1148 | raw_spin_lock_irqsave(hlist_lock, *flags); | |
ef53d9c5 | 1149 | } |
820aede0 | 1150 | NOKPROBE_SYMBOL(kretprobe_table_lock); |
ef53d9c5 | 1151 | |
820aede0 MH |
1152 | void kretprobe_hash_unlock(struct task_struct *tsk, |
1153 | unsigned long *flags) | |
635c17c2 | 1154 | __releases(hlist_lock) |
ef53d9c5 S |
1155 | { |
1156 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1157 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1158 | |
1159 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1160 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
ef53d9c5 | 1161 | } |
820aede0 | 1162 | NOKPROBE_SYMBOL(kretprobe_hash_unlock); |
ef53d9c5 | 1163 | |
820aede0 MH |
1164 | static void kretprobe_table_unlock(unsigned long hash, |
1165 | unsigned long *flags) | |
635c17c2 | 1166 | __releases(hlist_lock) |
ef53d9c5 | 1167 | { |
ec484608 TG |
1168 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1169 | raw_spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 | 1170 | } |
820aede0 | 1171 | NOKPROBE_SYMBOL(kretprobe_table_unlock); |
b94cce92 | 1172 | |
b94cce92 | 1173 | /* |
c6fd91f0 | 1174 | * This function is called from finish_task_switch when task tk becomes dead, |
1175 | * so that we can recycle any function-return probe instances associated | |
1176 | * with this task. These left over instances represent probed functions | |
1177 | * that have been called but will never return. | |
b94cce92 | 1178 | */ |
820aede0 | 1179 | void kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 1180 | { |
62c27be0 | 1181 | struct kretprobe_instance *ri; |
99219a3f | 1182 | struct hlist_head *head, empty_rp; |
b67bfe0d | 1183 | struct hlist_node *tmp; |
ef53d9c5 | 1184 | unsigned long hash, flags = 0; |
802eae7c | 1185 | |
ef53d9c5 S |
1186 | if (unlikely(!kprobes_initialized)) |
1187 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
1188 | return; | |
1189 | ||
d496aab5 | 1190 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 S |
1191 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1192 | head = &kretprobe_inst_table[hash]; | |
1193 | kretprobe_table_lock(hash, &flags); | |
b67bfe0d | 1194 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
62c27be0 | 1195 | if (ri->task == tk) |
99219a3f | 1196 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 1197 | } |
ef53d9c5 | 1198 | kretprobe_table_unlock(hash, &flags); |
b67bfe0d | 1199 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
99219a3f | 1200 | hlist_del(&ri->hlist); |
1201 | kfree(ri); | |
1202 | } | |
b94cce92 | 1203 | } |
820aede0 | 1204 | NOKPROBE_SYMBOL(kprobe_flush_task); |
b94cce92 | 1205 | |
b94cce92 HN |
1206 | static inline void free_rp_inst(struct kretprobe *rp) |
1207 | { | |
1208 | struct kretprobe_instance *ri; | |
b67bfe0d | 1209 | struct hlist_node *next; |
4c4308cb | 1210 | |
b67bfe0d | 1211 | hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) { |
ef53d9c5 | 1212 | hlist_del(&ri->hlist); |
b94cce92 HN |
1213 | kfree(ri); |
1214 | } | |
1215 | } | |
1216 | ||
820aede0 | 1217 | static void cleanup_rp_inst(struct kretprobe *rp) |
4a296e07 | 1218 | { |
ef53d9c5 | 1219 | unsigned long flags, hash; |
4a296e07 | 1220 | struct kretprobe_instance *ri; |
b67bfe0d | 1221 | struct hlist_node *next; |
ef53d9c5 S |
1222 | struct hlist_head *head; |
1223 | ||
4a296e07 | 1224 | /* No race here */ |
ef53d9c5 S |
1225 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1226 | kretprobe_table_lock(hash, &flags); | |
1227 | head = &kretprobe_inst_table[hash]; | |
b67bfe0d | 1228 | hlist_for_each_entry_safe(ri, next, head, hlist) { |
ef53d9c5 S |
1229 | if (ri->rp == rp) |
1230 | ri->rp = NULL; | |
1231 | } | |
1232 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 1233 | } |
4a296e07 MH |
1234 | free_rp_inst(rp); |
1235 | } | |
820aede0 | 1236 | NOKPROBE_SYMBOL(cleanup_rp_inst); |
4a296e07 | 1237 | |
8b0914ea | 1238 | /* |
b918e5e6 | 1239 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
1240 | * second jprobe at the address - two jprobes can't coexist |
1241 | */ | |
55479f64 | 1242 | static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1243 | { |
de5bd88d | 1244 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
afd66255 MH |
1245 | |
1246 | if (p->break_handler || p->post_handler) | |
6274de49 | 1247 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1248 | |
8b0914ea | 1249 | if (p->break_handler) { |
b918e5e6 | 1250 | if (ap->break_handler) |
36721656 | 1251 | return -EEXIST; |
b918e5e6 MH |
1252 | list_add_tail_rcu(&p->list, &ap->list); |
1253 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 1254 | } else |
b918e5e6 MH |
1255 | list_add_rcu(&p->list, &ap->list); |
1256 | if (p->post_handler && !ap->post_handler) | |
1257 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1258 | |
8b0914ea PP |
1259 | return 0; |
1260 | } | |
1261 | ||
64f562c6 AM |
1262 | /* |
1263 | * Fill in the required fields of the "manager kprobe". Replace the | |
1264 | * earlier kprobe in the hlist with the manager kprobe | |
1265 | */ | |
55479f64 | 1266 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1267 | { |
afd66255 | 1268 | /* Copy p's insn slot to ap */ |
8b0914ea | 1269 | copy_kprobe(p, ap); |
a9ad965e | 1270 | flush_insn_slot(ap); |
64f562c6 | 1271 | ap->addr = p->addr; |
afd66255 | 1272 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1273 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 1274 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
1275 | /* We don't care the kprobe which has gone. */ |
1276 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1277 | ap->post_handler = aggr_post_handler; |
e8386a0c | 1278 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 1279 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
1280 | |
1281 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1282 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1283 | |
afd66255 | 1284 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1285 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1286 | } |
1287 | ||
1288 | /* | |
1289 | * This is the second or subsequent kprobe at the address - handle | |
1290 | * the intricacies | |
64f562c6 | 1291 | */ |
55479f64 | 1292 | static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
64f562c6 AM |
1293 | { |
1294 | int ret = 0; | |
6d8e40a8 | 1295 | struct kprobe *ap = orig_p; |
64f562c6 | 1296 | |
25764288 MH |
1297 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1298 | jump_label_lock(); | |
1299 | /* | |
1300 | * Get online CPUs to avoid text_mutex deadlock.with stop machine, | |
1301 | * which is invoked by unoptimize_kprobe() in add_new_kprobe() | |
1302 | */ | |
1303 | get_online_cpus(); | |
1304 | mutex_lock(&text_mutex); | |
1305 | ||
6d8e40a8 MH |
1306 | if (!kprobe_aggrprobe(orig_p)) { |
1307 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
1308 | ap = alloc_aggr_kprobe(orig_p); | |
25764288 MH |
1309 | if (!ap) { |
1310 | ret = -ENOMEM; | |
1311 | goto out; | |
1312 | } | |
6d8e40a8 | 1313 | init_aggr_kprobe(ap, orig_p); |
6274de49 | 1314 | } else if (kprobe_unused(ap)) |
0490cd1f MH |
1315 | /* This probe is going to die. Rescue it */ |
1316 | reuse_unused_kprobe(ap); | |
b918e5e6 MH |
1317 | |
1318 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1319 | /* |
1320 | * Attempting to insert new probe at the same location that | |
1321 | * had a probe in the module vaddr area which already | |
1322 | * freed. So, the instruction slot has already been | |
1323 | * released. We need a new slot for the new probe. | |
1324 | */ | |
b918e5e6 | 1325 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1326 | if (ret) |
b918e5e6 MH |
1327 | /* |
1328 | * Even if fail to allocate new slot, don't need to | |
1329 | * free aggr_probe. It will be used next time, or | |
1330 | * freed by unregister_kprobe. | |
1331 | */ | |
25764288 | 1332 | goto out; |
de5bd88d | 1333 | |
afd66255 MH |
1334 | /* Prepare optimized instructions if possible. */ |
1335 | prepare_optimized_kprobe(ap); | |
1336 | ||
e8386a0c | 1337 | /* |
de5bd88d MH |
1338 | * Clear gone flag to prevent allocating new slot again, and |
1339 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1340 | */ |
de5bd88d MH |
1341 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1342 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1343 | } |
b918e5e6 | 1344 | |
afd66255 | 1345 | /* Copy ap's insn slot to p */ |
b918e5e6 | 1346 | copy_kprobe(ap, p); |
25764288 MH |
1347 | ret = add_new_kprobe(ap, p); |
1348 | ||
1349 | out: | |
1350 | mutex_unlock(&text_mutex); | |
1351 | put_online_cpus(); | |
1352 | jump_label_unlock(); | |
1353 | ||
1354 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1355 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
1356 | if (!kprobes_all_disarmed) | |
1357 | /* Arm the breakpoint again. */ | |
1358 | arm_kprobe(ap); | |
1359 | } | |
1360 | return ret; | |
64f562c6 AM |
1361 | } |
1362 | ||
be8f2743 MH |
1363 | bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
1364 | { | |
1365 | /* The __kprobes marked functions and entry code must not be probed */ | |
1366 | return addr >= (unsigned long)__kprobes_text_start && | |
1367 | addr < (unsigned long)__kprobes_text_end; | |
1368 | } | |
1369 | ||
e5779e8e | 1370 | bool within_kprobe_blacklist(unsigned long addr) |
d0aaff97 | 1371 | { |
376e2424 | 1372 | struct kprobe_blacklist_entry *ent; |
3d8d996e | 1373 | |
be8f2743 | 1374 | if (arch_within_kprobe_blacklist(addr)) |
376e2424 | 1375 | return true; |
3d8d996e SD |
1376 | /* |
1377 | * If there exists a kprobe_blacklist, verify and | |
1378 | * fail any probe registration in the prohibited area | |
1379 | */ | |
376e2424 MH |
1380 | list_for_each_entry(ent, &kprobe_blacklist, list) { |
1381 | if (addr >= ent->start_addr && addr < ent->end_addr) | |
1382 | return true; | |
3d8d996e | 1383 | } |
376e2424 MH |
1384 | |
1385 | return false; | |
d0aaff97 PP |
1386 | } |
1387 | ||
b2a5cd69 MH |
1388 | /* |
1389 | * If we have a symbol_name argument, look it up and add the offset field | |
1390 | * to it. This way, we can specify a relative address to a symbol. | |
bc81d48d MH |
1391 | * This returns encoded errors if it fails to look up symbol or invalid |
1392 | * combination of parameters. | |
b2a5cd69 | 1393 | */ |
1d585e70 NR |
1394 | static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr, |
1395 | const char *symbol_name, unsigned int offset) | |
b2a5cd69 | 1396 | { |
1d585e70 | 1397 | if ((symbol_name && addr) || (!symbol_name && !addr)) |
bc81d48d MH |
1398 | goto invalid; |
1399 | ||
1d585e70 NR |
1400 | if (symbol_name) { |
1401 | kprobe_lookup_name(symbol_name, addr); | |
bc81d48d MH |
1402 | if (!addr) |
1403 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1404 | } |
1405 | ||
1d585e70 | 1406 | addr = (kprobe_opcode_t *)(((char *)addr) + offset); |
bc81d48d MH |
1407 | if (addr) |
1408 | return addr; | |
1409 | ||
1410 | invalid: | |
1411 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1412 | } |
1413 | ||
1d585e70 NR |
1414 | static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
1415 | { | |
1416 | return _kprobe_addr(p->addr, p->symbol_name, p->offset); | |
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 | |
5f6bee34 NR |
1746 | int __weak kprobe_exceptions_notify(struct notifier_block *self, |
1747 | unsigned long val, void *data) | |
fc62d020 NR |
1748 | { |
1749 | return NOTIFY_DONE; | |
1750 | } | |
5f6bee34 | 1751 | NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
fc62d020 | 1752 | |
1da177e4 | 1753 | static struct notifier_block kprobe_exceptions_nb = { |
3d5631e0 AK |
1754 | .notifier_call = kprobe_exceptions_notify, |
1755 | .priority = 0x7fffffff /* we need to be notified first */ | |
1756 | }; | |
1757 | ||
3d7e3382 ME |
1758 | unsigned long __weak arch_deref_entry_point(void *entry) |
1759 | { | |
1760 | return (unsigned long)entry; | |
1761 | } | |
1da177e4 | 1762 | |
55479f64 | 1763 | int register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 1764 | { |
26b31c19 MH |
1765 | struct jprobe *jp; |
1766 | int ret = 0, i; | |
3d7e3382 | 1767 | |
26b31c19 | 1768 | if (num <= 0) |
3d7e3382 | 1769 | return -EINVAL; |
26b31c19 | 1770 | for (i = 0; i < num; i++) { |
05662bdb | 1771 | unsigned long addr, offset; |
26b31c19 MH |
1772 | jp = jps[i]; |
1773 | addr = arch_deref_entry_point(jp->entry); | |
1774 | ||
05662bdb NK |
1775 | /* Verify probepoint is a function entry point */ |
1776 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && | |
1777 | offset == 0) { | |
1778 | jp->kp.pre_handler = setjmp_pre_handler; | |
1779 | jp->kp.break_handler = longjmp_break_handler; | |
1780 | ret = register_kprobe(&jp->kp); | |
1781 | } else | |
1782 | ret = -EINVAL; | |
edbaadbe | 1783 | |
67dddaad MH |
1784 | if (ret < 0) { |
1785 | if (i > 0) | |
1786 | unregister_jprobes(jps, i); | |
26b31c19 MH |
1787 | break; |
1788 | } | |
1789 | } | |
1790 | return ret; | |
1791 | } | |
99081ab5 | 1792 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 1793 | |
55479f64 | 1794 | int register_jprobe(struct jprobe *jp) |
26b31c19 | 1795 | { |
49ad2fd7 | 1796 | return register_jprobes(&jp, 1); |
1da177e4 | 1797 | } |
99081ab5 | 1798 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 1799 | |
55479f64 | 1800 | void unregister_jprobe(struct jprobe *jp) |
1da177e4 | 1801 | { |
26b31c19 MH |
1802 | unregister_jprobes(&jp, 1); |
1803 | } | |
99081ab5 | 1804 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 1805 | |
55479f64 | 1806 | void unregister_jprobes(struct jprobe **jps, int num) |
26b31c19 MH |
1807 | { |
1808 | int i; | |
1809 | ||
1810 | if (num <= 0) | |
1811 | return; | |
1812 | mutex_lock(&kprobe_mutex); | |
1813 | for (i = 0; i < num; i++) | |
1814 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
1815 | jps[i]->kp.addr = NULL; | |
1816 | mutex_unlock(&kprobe_mutex); | |
1817 | ||
1818 | synchronize_sched(); | |
1819 | for (i = 0; i < num; i++) { | |
1820 | if (jps[i]->kp.addr) | |
1821 | __unregister_kprobe_bottom(&jps[i]->kp); | |
1822 | } | |
1da177e4 | 1823 | } |
99081ab5 | 1824 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 1825 | |
9edddaa2 | 1826 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1827 | /* |
1828 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1829 | * hits it will set up the return probe. | |
1830 | */ | |
820aede0 | 1831 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
e65cefe8 AB |
1832 | { |
1833 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1834 | unsigned long hash, flags = 0; |
1835 | struct kretprobe_instance *ri; | |
e65cefe8 | 1836 | |
f96f5678 MH |
1837 | /* |
1838 | * To avoid deadlocks, prohibit return probing in NMI contexts, | |
1839 | * just skip the probe and increase the (inexact) 'nmissed' | |
1840 | * statistical counter, so that the user is informed that | |
1841 | * something happened: | |
1842 | */ | |
1843 | if (unlikely(in_nmi())) { | |
1844 | rp->nmissed++; | |
1845 | return 0; | |
1846 | } | |
1847 | ||
1848 | /* TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 | 1849 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
ec484608 | 1850 | raw_spin_lock_irqsave(&rp->lock, flags); |
4c4308cb | 1851 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1852 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1853 | struct kretprobe_instance, hlist); |
1854 | hlist_del(&ri->hlist); | |
ec484608 | 1855 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1856 | |
4c4308cb CH |
1857 | ri->rp = rp; |
1858 | ri->task = current; | |
f47cd9b5 | 1859 | |
55ca6140 JL |
1860 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1861 | raw_spin_lock_irqsave(&rp->lock, flags); | |
1862 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
1863 | raw_spin_unlock_irqrestore(&rp->lock, flags); | |
f47cd9b5 | 1864 | return 0; |
55ca6140 | 1865 | } |
f47cd9b5 | 1866 | |
4c4308cb CH |
1867 | arch_prepare_kretprobe(ri, regs); |
1868 | ||
1869 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1870 | INIT_HLIST_NODE(&ri->hlist); |
1871 | kretprobe_table_lock(hash, &flags); | |
1872 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1873 | kretprobe_table_unlock(hash, &flags); | |
1874 | } else { | |
4c4308cb | 1875 | rp->nmissed++; |
ec484608 | 1876 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1877 | } |
e65cefe8 AB |
1878 | return 0; |
1879 | } | |
820aede0 | 1880 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
e65cefe8 | 1881 | |
90ec5e89 NR |
1882 | bool __weak arch_function_offset_within_entry(unsigned long offset) |
1883 | { | |
1884 | return !offset; | |
1885 | } | |
1886 | ||
1d585e70 NR |
1887 | bool function_offset_within_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) |
1888 | { | |
1889 | kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset); | |
1890 | ||
1891 | if (IS_ERR(kp_addr)) | |
1892 | return false; | |
1893 | ||
1894 | if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) || | |
1895 | !arch_function_offset_within_entry(offset)) | |
1896 | return false; | |
1897 | ||
1898 | return true; | |
1899 | } | |
1900 | ||
55479f64 | 1901 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1902 | { |
1903 | int ret = 0; | |
1904 | struct kretprobe_instance *inst; | |
1905 | int i; | |
b2a5cd69 | 1906 | void *addr; |
90ec5e89 | 1907 | |
1d585e70 | 1908 | if (!function_offset_within_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset)) |
90ec5e89 | 1909 | return -EINVAL; |
f438d914 MH |
1910 | |
1911 | if (kretprobe_blacklist_size) { | |
b2a5cd69 | 1912 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
1913 | if (IS_ERR(addr)) |
1914 | return PTR_ERR(addr); | |
f438d914 MH |
1915 | |
1916 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1917 | if (kretprobe_blacklist[i].addr == addr) | |
1918 | return -EINVAL; | |
1919 | } | |
1920 | } | |
b94cce92 HN |
1921 | |
1922 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1923 | rp->kp.post_handler = NULL; |
1924 | rp->kp.fault_handler = NULL; | |
1925 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1926 | |
1927 | /* Pre-allocate memory for max kretprobe instances */ | |
1928 | if (rp->maxactive <= 0) { | |
1929 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1930 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1931 | #else |
4dae560f | 1932 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1933 | #endif |
1934 | } | |
ec484608 | 1935 | raw_spin_lock_init(&rp->lock); |
b94cce92 HN |
1936 | INIT_HLIST_HEAD(&rp->free_instances); |
1937 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1938 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1939 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1940 | if (inst == NULL) { |
1941 | free_rp_inst(rp); | |
1942 | return -ENOMEM; | |
1943 | } | |
ef53d9c5 S |
1944 | INIT_HLIST_NODE(&inst->hlist); |
1945 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1946 | } |
1947 | ||
1948 | rp->nmissed = 0; | |
1949 | /* Establish function entry probe point */ | |
49ad2fd7 | 1950 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1951 | if (ret != 0) |
b94cce92 HN |
1952 | free_rp_inst(rp); |
1953 | return ret; | |
1954 | } | |
99081ab5 | 1955 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1956 | |
55479f64 | 1957 | int register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1958 | { |
1959 | int ret = 0, i; | |
1960 | ||
1961 | if (num <= 0) | |
1962 | return -EINVAL; | |
1963 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1964 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1965 | if (ret < 0) { |
1966 | if (i > 0) | |
1967 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1968 | break; |
1969 | } | |
1970 | } | |
1971 | return ret; | |
1972 | } | |
99081ab5 | 1973 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1974 | |
55479f64 | 1975 | void unregister_kretprobe(struct kretprobe *rp) |
4a296e07 MH |
1976 | { |
1977 | unregister_kretprobes(&rp, 1); | |
1978 | } | |
99081ab5 | 1979 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1980 | |
55479f64 | 1981 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1982 | { |
1983 | int i; | |
1984 | ||
1985 | if (num <= 0) | |
1986 | return; | |
1987 | mutex_lock(&kprobe_mutex); | |
1988 | for (i = 0; i < num; i++) | |
1989 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1990 | rps[i]->kp.addr = NULL; | |
1991 | mutex_unlock(&kprobe_mutex); | |
1992 | ||
1993 | synchronize_sched(); | |
1994 | for (i = 0; i < num; i++) { | |
1995 | if (rps[i]->kp.addr) { | |
1996 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1997 | cleanup_rp_inst(rps[i]); | |
1998 | } | |
1999 | } | |
2000 | } | |
99081ab5 | 2001 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 2002 | |
9edddaa2 | 2003 | #else /* CONFIG_KRETPROBES */ |
55479f64 | 2004 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
2005 | { |
2006 | return -ENOSYS; | |
2007 | } | |
99081ab5 | 2008 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2009 | |
55479f64 | 2010 | int register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 2011 | { |
4a296e07 | 2012 | return -ENOSYS; |
346fd59b | 2013 | } |
99081ab5 MH |
2014 | EXPORT_SYMBOL_GPL(register_kretprobes); |
2015 | ||
55479f64 | 2016 | void unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 2017 | { |
4a296e07 | 2018 | } |
99081ab5 | 2019 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 2020 | |
55479f64 | 2021 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2022 | { |
2023 | } | |
99081ab5 | 2024 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 2025 | |
820aede0 | 2026 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
4a296e07 MH |
2027 | { |
2028 | return 0; | |
b94cce92 | 2029 | } |
820aede0 | 2030 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
b94cce92 | 2031 | |
4a296e07 MH |
2032 | #endif /* CONFIG_KRETPROBES */ |
2033 | ||
e8386a0c | 2034 | /* Set the kprobe gone and remove its instruction buffer. */ |
55479f64 | 2035 | static void kill_kprobe(struct kprobe *p) |
e8386a0c MH |
2036 | { |
2037 | struct kprobe *kp; | |
de5bd88d | 2038 | |
e8386a0c | 2039 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 2040 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
2041 | /* |
2042 | * If this is an aggr_kprobe, we have to list all the | |
2043 | * chained probes and mark them GONE. | |
2044 | */ | |
2045 | list_for_each_entry_rcu(kp, &p->list, list) | |
2046 | kp->flags |= KPROBE_FLAG_GONE; | |
2047 | p->post_handler = NULL; | |
2048 | p->break_handler = NULL; | |
afd66255 | 2049 | kill_optimized_kprobe(p); |
e8386a0c MH |
2050 | } |
2051 | /* | |
2052 | * Here, we can remove insn_slot safely, because no thread calls | |
2053 | * the original probed function (which will be freed soon) any more. | |
2054 | */ | |
2055 | arch_remove_kprobe(p); | |
2056 | } | |
2057 | ||
c0614829 | 2058 | /* Disable one kprobe */ |
55479f64 | 2059 | int disable_kprobe(struct kprobe *kp) |
c0614829 MH |
2060 | { |
2061 | int ret = 0; | |
c0614829 MH |
2062 | |
2063 | mutex_lock(&kprobe_mutex); | |
2064 | ||
6f0f1dd7 MH |
2065 | /* Disable this kprobe */ |
2066 | if (__disable_kprobe(kp) == NULL) | |
c0614829 | 2067 | ret = -EINVAL; |
c0614829 | 2068 | |
c0614829 MH |
2069 | mutex_unlock(&kprobe_mutex); |
2070 | return ret; | |
2071 | } | |
2072 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
2073 | ||
2074 | /* Enable one kprobe */ | |
55479f64 | 2075 | int enable_kprobe(struct kprobe *kp) |
c0614829 MH |
2076 | { |
2077 | int ret = 0; | |
2078 | struct kprobe *p; | |
2079 | ||
2080 | mutex_lock(&kprobe_mutex); | |
2081 | ||
2082 | /* Check whether specified probe is valid. */ | |
2083 | p = __get_valid_kprobe(kp); | |
2084 | if (unlikely(p == NULL)) { | |
2085 | ret = -EINVAL; | |
2086 | goto out; | |
2087 | } | |
2088 | ||
2089 | if (kprobe_gone(kp)) { | |
2090 | /* This kprobe has gone, we couldn't enable it. */ | |
2091 | ret = -EINVAL; | |
2092 | goto out; | |
2093 | } | |
2094 | ||
2095 | if (p != kp) | |
2096 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
2097 | ||
2098 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
2099 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
2100 | arm_kprobe(p); | |
2101 | } | |
2102 | out: | |
2103 | mutex_unlock(&kprobe_mutex); | |
2104 | return ret; | |
2105 | } | |
2106 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
2107 | ||
820aede0 | 2108 | void dump_kprobe(struct kprobe *kp) |
24851d24 FW |
2109 | { |
2110 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
2111 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
2112 | kp->symbol_name, kp->addr, kp->offset); | |
2113 | } | |
820aede0 | 2114 | NOKPROBE_SYMBOL(dump_kprobe); |
24851d24 | 2115 | |
376e2424 MH |
2116 | /* |
2117 | * Lookup and populate the kprobe_blacklist. | |
2118 | * | |
2119 | * Unlike the kretprobe blacklist, we'll need to determine | |
2120 | * the range of addresses that belong to the said functions, | |
2121 | * since a kprobe need not necessarily be at the beginning | |
2122 | * of a function. | |
2123 | */ | |
2124 | static int __init populate_kprobe_blacklist(unsigned long *start, | |
2125 | unsigned long *end) | |
2126 | { | |
2127 | unsigned long *iter; | |
2128 | struct kprobe_blacklist_entry *ent; | |
d81b4253 | 2129 | unsigned long entry, offset = 0, size = 0; |
376e2424 MH |
2130 | |
2131 | for (iter = start; iter < end; iter++) { | |
d81b4253 MH |
2132 | entry = arch_deref_entry_point((void *)*iter); |
2133 | ||
2134 | if (!kernel_text_address(entry) || | |
2135 | !kallsyms_lookup_size_offset(entry, &size, &offset)) { | |
2136 | pr_err("Failed to find blacklist at %p\n", | |
2137 | (void *)entry); | |
376e2424 MH |
2138 | continue; |
2139 | } | |
2140 | ||
2141 | ent = kmalloc(sizeof(*ent), GFP_KERNEL); | |
2142 | if (!ent) | |
2143 | return -ENOMEM; | |
d81b4253 MH |
2144 | ent->start_addr = entry; |
2145 | ent->end_addr = entry + size; | |
376e2424 MH |
2146 | INIT_LIST_HEAD(&ent->list); |
2147 | list_add_tail(&ent->list, &kprobe_blacklist); | |
2148 | } | |
2149 | return 0; | |
2150 | } | |
2151 | ||
e8386a0c | 2152 | /* Module notifier call back, checking kprobes on the module */ |
55479f64 MH |
2153 | static int kprobes_module_callback(struct notifier_block *nb, |
2154 | unsigned long val, void *data) | |
e8386a0c MH |
2155 | { |
2156 | struct module *mod = data; | |
2157 | struct hlist_head *head; | |
e8386a0c MH |
2158 | struct kprobe *p; |
2159 | unsigned int i; | |
f24659d9 | 2160 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2161 | |
f24659d9 | 2162 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2163 | return NOTIFY_DONE; |
2164 | ||
2165 | /* | |
f24659d9 MH |
2166 | * When MODULE_STATE_GOING was notified, both of module .text and |
2167 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
2168 | * notified, only .init.text section would be freed. We need to | |
2169 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
2170 | */ |
2171 | mutex_lock(&kprobe_mutex); | |
2172 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2173 | head = &kprobe_table[i]; | |
b67bfe0d | 2174 | hlist_for_each_entry_rcu(p, head, hlist) |
f24659d9 MH |
2175 | if (within_module_init((unsigned long)p->addr, mod) || |
2176 | (checkcore && | |
2177 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2178 | /* |
2179 | * The vaddr this probe is installed will soon | |
2180 | * be vfreed buy not synced to disk. Hence, | |
2181 | * disarming the breakpoint isn't needed. | |
2182 | */ | |
2183 | kill_kprobe(p); | |
2184 | } | |
2185 | } | |
2186 | mutex_unlock(&kprobe_mutex); | |
2187 | return NOTIFY_DONE; | |
2188 | } | |
2189 | ||
2190 | static struct notifier_block kprobe_module_nb = { | |
2191 | .notifier_call = kprobes_module_callback, | |
2192 | .priority = 0 | |
2193 | }; | |
2194 | ||
376e2424 MH |
2195 | /* Markers of _kprobe_blacklist section */ |
2196 | extern unsigned long __start_kprobe_blacklist[]; | |
2197 | extern unsigned long __stop_kprobe_blacklist[]; | |
2198 | ||
1da177e4 LT |
2199 | static int __init init_kprobes(void) |
2200 | { | |
2201 | int i, err = 0; | |
2202 | ||
2203 | /* FIXME allocate the probe table, currently defined statically */ | |
2204 | /* initialize all list heads */ | |
b94cce92 | 2205 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 2206 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 2207 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ec484608 | 2208 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 2209 | } |
1da177e4 | 2210 | |
376e2424 MH |
2211 | err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
2212 | __stop_kprobe_blacklist); | |
2213 | if (err) { | |
2214 | pr_err("kprobes: failed to populate blacklist: %d\n", err); | |
2215 | pr_err("Please take care of using kprobes.\n"); | |
3d8d996e SD |
2216 | } |
2217 | ||
f438d914 MH |
2218 | if (kretprobe_blacklist_size) { |
2219 | /* lookup the function address from its name */ | |
2220 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
2221 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
2222 | kretprobe_blacklist[i].addr); | |
2223 | if (!kretprobe_blacklist[i].addr) | |
2224 | printk("kretprobe: lookup failed: %s\n", | |
2225 | kretprobe_blacklist[i].name); | |
2226 | } | |
2227 | } | |
2228 | ||
b2be84df MH |
2229 | #if defined(CONFIG_OPTPROBES) |
2230 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) | |
afd66255 MH |
2231 | /* Init kprobe_optinsn_slots */ |
2232 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
2233 | #endif | |
b2be84df MH |
2234 | /* By default, kprobes can be optimized */ |
2235 | kprobes_allow_optimization = true; | |
2236 | #endif | |
afd66255 | 2237 | |
e579abeb MH |
2238 | /* By default, kprobes are armed */ |
2239 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2240 | |
6772926b | 2241 | err = arch_init_kprobes(); |
802eae7c RL |
2242 | if (!err) |
2243 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
2244 | if (!err) |
2245 | err = register_module_notifier(&kprobe_module_nb); | |
2246 | ||
ef53d9c5 | 2247 | kprobes_initialized = (err == 0); |
802eae7c | 2248 | |
8c1c9356 AM |
2249 | if (!err) |
2250 | init_test_probes(); | |
1da177e4 LT |
2251 | return err; |
2252 | } | |
2253 | ||
346fd59b | 2254 | #ifdef CONFIG_DEBUG_FS |
55479f64 | 2255 | static void report_probe(struct seq_file *pi, struct kprobe *p, |
afd66255 | 2256 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2257 | { |
2258 | char *kprobe_type; | |
2259 | ||
2260 | if (p->pre_handler == pre_handler_kretprobe) | |
2261 | kprobe_type = "r"; | |
2262 | else if (p->pre_handler == setjmp_pre_handler) | |
2263 | kprobe_type = "j"; | |
2264 | else | |
2265 | kprobe_type = "k"; | |
afd66255 | 2266 | |
346fd59b | 2267 | if (sym) |
afd66255 | 2268 | seq_printf(pi, "%p %s %s+0x%x %s ", |
de5bd88d | 2269 | p->addr, kprobe_type, sym, offset, |
afd66255 | 2270 | (modname ? modname : " ")); |
346fd59b | 2271 | else |
afd66255 MH |
2272 | seq_printf(pi, "%p %s %p ", |
2273 | p->addr, kprobe_type, p->addr); | |
2274 | ||
2275 | if (!pp) | |
2276 | pp = p; | |
ae6aa16f | 2277 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2278 | (kprobe_gone(p) ? "[GONE]" : ""), |
2279 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2280 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2281 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2282 | } |
2283 | ||
55479f64 | 2284 | static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
346fd59b SD |
2285 | { |
2286 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2287 | } | |
2288 | ||
55479f64 | 2289 | static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
346fd59b SD |
2290 | { |
2291 | (*pos)++; | |
2292 | if (*pos >= KPROBE_TABLE_SIZE) | |
2293 | return NULL; | |
2294 | return pos; | |
2295 | } | |
2296 | ||
55479f64 | 2297 | static void kprobe_seq_stop(struct seq_file *f, void *v) |
346fd59b SD |
2298 | { |
2299 | /* Nothing to do */ | |
2300 | } | |
2301 | ||
55479f64 | 2302 | static int show_kprobe_addr(struct seq_file *pi, void *v) |
346fd59b SD |
2303 | { |
2304 | struct hlist_head *head; | |
346fd59b SD |
2305 | struct kprobe *p, *kp; |
2306 | const char *sym = NULL; | |
2307 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 2308 | unsigned long offset = 0; |
ab767865 | 2309 | char *modname, namebuf[KSYM_NAME_LEN]; |
346fd59b SD |
2310 | |
2311 | head = &kprobe_table[i]; | |
2312 | preempt_disable(); | |
b67bfe0d | 2313 | hlist_for_each_entry_rcu(p, head, hlist) { |
ffb45122 | 2314 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2315 | &offset, &modname, namebuf); |
afd66255 | 2316 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2317 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2318 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2319 | } else |
afd66255 | 2320 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2321 | } |
2322 | preempt_enable(); | |
2323 | return 0; | |
2324 | } | |
2325 | ||
88e9d34c | 2326 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
2327 | .start = kprobe_seq_start, |
2328 | .next = kprobe_seq_next, | |
2329 | .stop = kprobe_seq_stop, | |
2330 | .show = show_kprobe_addr | |
2331 | }; | |
2332 | ||
55479f64 | 2333 | static int kprobes_open(struct inode *inode, struct file *filp) |
346fd59b SD |
2334 | { |
2335 | return seq_open(filp, &kprobes_seq_ops); | |
2336 | } | |
2337 | ||
828c0950 | 2338 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
2339 | .open = kprobes_open, |
2340 | .read = seq_read, | |
2341 | .llseek = seq_lseek, | |
2342 | .release = seq_release, | |
2343 | }; | |
2344 | ||
63724740 MH |
2345 | /* kprobes/blacklist -- shows which functions can not be probed */ |
2346 | static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) | |
2347 | { | |
2348 | return seq_list_start(&kprobe_blacklist, *pos); | |
2349 | } | |
2350 | ||
2351 | static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
2352 | { | |
2353 | return seq_list_next(v, &kprobe_blacklist, pos); | |
2354 | } | |
2355 | ||
2356 | static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) | |
2357 | { | |
2358 | struct kprobe_blacklist_entry *ent = | |
2359 | list_entry(v, struct kprobe_blacklist_entry, list); | |
2360 | ||
2361 | seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr, | |
2362 | (void *)ent->end_addr, (void *)ent->start_addr); | |
2363 | return 0; | |
2364 | } | |
2365 | ||
2366 | static const struct seq_operations kprobe_blacklist_seq_ops = { | |
2367 | .start = kprobe_blacklist_seq_start, | |
2368 | .next = kprobe_blacklist_seq_next, | |
2369 | .stop = kprobe_seq_stop, /* Reuse void function */ | |
2370 | .show = kprobe_blacklist_seq_show, | |
2371 | }; | |
2372 | ||
2373 | static int kprobe_blacklist_open(struct inode *inode, struct file *filp) | |
2374 | { | |
2375 | return seq_open(filp, &kprobe_blacklist_seq_ops); | |
2376 | } | |
2377 | ||
2378 | static const struct file_operations debugfs_kprobe_blacklist_ops = { | |
2379 | .open = kprobe_blacklist_open, | |
2380 | .read = seq_read, | |
2381 | .llseek = seq_lseek, | |
2382 | .release = seq_release, | |
2383 | }; | |
2384 | ||
55479f64 | 2385 | static void arm_all_kprobes(void) |
bf8f6e5b AM |
2386 | { |
2387 | struct hlist_head *head; | |
bf8f6e5b AM |
2388 | struct kprobe *p; |
2389 | unsigned int i; | |
2390 | ||
2391 | mutex_lock(&kprobe_mutex); | |
2392 | ||
e579abeb MH |
2393 | /* If kprobes are armed, just return */ |
2394 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2395 | goto already_enabled; |
2396 | ||
977ad481 WN |
2397 | /* |
2398 | * optimize_kprobe() called by arm_kprobe() checks | |
2399 | * kprobes_all_disarmed, so set kprobes_all_disarmed before | |
2400 | * arm_kprobe. | |
2401 | */ | |
2402 | kprobes_all_disarmed = false; | |
afd66255 | 2403 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2404 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2405 | head = &kprobe_table[i]; | |
b67bfe0d | 2406 | hlist_for_each_entry_rcu(p, head, hlist) |
de5bd88d | 2407 | if (!kprobe_disabled(p)) |
ae6aa16f | 2408 | arm_kprobe(p); |
bf8f6e5b AM |
2409 | } |
2410 | ||
bf8f6e5b AM |
2411 | printk(KERN_INFO "Kprobes globally enabled\n"); |
2412 | ||
2413 | already_enabled: | |
2414 | mutex_unlock(&kprobe_mutex); | |
2415 | return; | |
2416 | } | |
2417 | ||
55479f64 | 2418 | static void disarm_all_kprobes(void) |
bf8f6e5b AM |
2419 | { |
2420 | struct hlist_head *head; | |
bf8f6e5b AM |
2421 | struct kprobe *p; |
2422 | unsigned int i; | |
2423 | ||
2424 | mutex_lock(&kprobe_mutex); | |
2425 | ||
e579abeb | 2426 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2427 | if (kprobes_all_disarmed) { |
2428 | mutex_unlock(&kprobe_mutex); | |
2429 | return; | |
2430 | } | |
bf8f6e5b | 2431 | |
e579abeb | 2432 | kprobes_all_disarmed = true; |
bf8f6e5b | 2433 | printk(KERN_INFO "Kprobes globally disabled\n"); |
afd66255 | 2434 | |
bf8f6e5b AM |
2435 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2436 | head = &kprobe_table[i]; | |
b67bfe0d | 2437 | hlist_for_each_entry_rcu(p, head, hlist) { |
de5bd88d | 2438 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
ae6aa16f | 2439 | disarm_kprobe(p, false); |
bf8f6e5b AM |
2440 | } |
2441 | } | |
bf8f6e5b | 2442 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2443 | |
6274de49 MH |
2444 | /* Wait for disarming all kprobes by optimizer */ |
2445 | wait_for_kprobe_optimizer(); | |
bf8f6e5b AM |
2446 | } |
2447 | ||
2448 | /* | |
2449 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2450 | * when the bool state is switched. We can reuse that facility when | |
2451 | * available | |
2452 | */ | |
2453 | static ssize_t read_enabled_file_bool(struct file *file, | |
2454 | char __user *user_buf, size_t count, loff_t *ppos) | |
2455 | { | |
2456 | char buf[3]; | |
2457 | ||
e579abeb | 2458 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
2459 | buf[0] = '1'; |
2460 | else | |
2461 | buf[0] = '0'; | |
2462 | buf[1] = '\n'; | |
2463 | buf[2] = 0x00; | |
2464 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2465 | } | |
2466 | ||
2467 | static ssize_t write_enabled_file_bool(struct file *file, | |
2468 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2469 | { | |
2470 | char buf[32]; | |
efeb156e | 2471 | size_t buf_size; |
bf8f6e5b AM |
2472 | |
2473 | buf_size = min(count, (sizeof(buf)-1)); | |
2474 | if (copy_from_user(buf, user_buf, buf_size)) | |
2475 | return -EFAULT; | |
2476 | ||
10fb46d5 | 2477 | buf[buf_size] = '\0'; |
bf8f6e5b AM |
2478 | switch (buf[0]) { |
2479 | case 'y': | |
2480 | case 'Y': | |
2481 | case '1': | |
e579abeb | 2482 | arm_all_kprobes(); |
bf8f6e5b AM |
2483 | break; |
2484 | case 'n': | |
2485 | case 'N': | |
2486 | case '0': | |
e579abeb | 2487 | disarm_all_kprobes(); |
bf8f6e5b | 2488 | break; |
10fb46d5 MK |
2489 | default: |
2490 | return -EINVAL; | |
bf8f6e5b AM |
2491 | } |
2492 | ||
2493 | return count; | |
2494 | } | |
2495 | ||
828c0950 | 2496 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2497 | .read = read_enabled_file_bool, |
2498 | .write = write_enabled_file_bool, | |
6038f373 | 2499 | .llseek = default_llseek, |
bf8f6e5b AM |
2500 | }; |
2501 | ||
55479f64 | 2502 | static int __init debugfs_kprobe_init(void) |
346fd59b SD |
2503 | { |
2504 | struct dentry *dir, *file; | |
bf8f6e5b | 2505 | unsigned int value = 1; |
346fd59b SD |
2506 | |
2507 | dir = debugfs_create_dir("kprobes", NULL); | |
2508 | if (!dir) | |
2509 | return -ENOMEM; | |
2510 | ||
e3869792 | 2511 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b | 2512 | &debugfs_kprobes_operations); |
63724740 MH |
2513 | if (!file) |
2514 | goto error; | |
346fd59b | 2515 | |
bf8f6e5b AM |
2516 | file = debugfs_create_file("enabled", 0600, dir, |
2517 | &value, &fops_kp); | |
63724740 MH |
2518 | if (!file) |
2519 | goto error; | |
2520 | ||
2521 | file = debugfs_create_file("blacklist", 0444, dir, NULL, | |
2522 | &debugfs_kprobe_blacklist_ops); | |
2523 | if (!file) | |
2524 | goto error; | |
bf8f6e5b | 2525 | |
346fd59b | 2526 | return 0; |
63724740 MH |
2527 | |
2528 | error: | |
2529 | debugfs_remove(dir); | |
2530 | return -ENOMEM; | |
346fd59b SD |
2531 | } |
2532 | ||
2533 | late_initcall(debugfs_kprobe_init); | |
2534 | #endif /* CONFIG_DEBUG_FS */ | |
2535 | ||
2536 | module_init(init_kprobes); | |
1da177e4 | 2537 | |
99081ab5 | 2538 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 2539 | EXPORT_SYMBOL_GPL(jprobe_return); |