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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Kernel Probes (KProbes) | |
1da177e4 | 4 | * |
1da177e4 LT |
5 | * Copyright (C) IBM Corporation, 2002, 2004 |
6 | * | |
7 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel | |
8 | * Probes initial implementation (includes suggestions from | |
9 | * Rusty Russell). | |
10 | * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with | |
11 | * hlists and exceptions notifier as suggested by Andi Kleen. | |
12 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes | |
13 | * interface to access function arguments. | |
14 | * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes | |
15 | * exceptions notifier to be first on the priority list. | |
b94cce92 HN |
16 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
17 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi | |
18 | * <prasanna@in.ibm.com> added function-return probes. | |
1da177e4 | 19 | */ |
9c89bb8e MH |
20 | |
21 | #define pr_fmt(fmt) "kprobes: " fmt | |
22 | ||
1da177e4 | 23 | #include <linux/kprobes.h> |
1da177e4 LT |
24 | #include <linux/hash.h> |
25 | #include <linux/init.h> | |
4e57b681 | 26 | #include <linux/slab.h> |
e3869792 | 27 | #include <linux/stddef.h> |
9984de1a | 28 | #include <linux/export.h> |
9ec4b1f3 | 29 | #include <linux/moduleloader.h> |
3a872d89 | 30 | #include <linux/kallsyms.h> |
b4c6c34a | 31 | #include <linux/freezer.h> |
346fd59b SD |
32 | #include <linux/seq_file.h> |
33 | #include <linux/debugfs.h> | |
b2be84df | 34 | #include <linux/sysctl.h> |
1eeb66a1 | 35 | #include <linux/kdebug.h> |
4460fdad | 36 | #include <linux/memory.h> |
4554dbcb | 37 | #include <linux/ftrace.h> |
afd66255 | 38 | #include <linux/cpu.h> |
bf5438fc | 39 | #include <linux/jump_label.h> |
fa68bd09 | 40 | #include <linux/static_call.h> |
69e49088 | 41 | #include <linux/perf_event.h> |
bf8f6e5b | 42 | |
bfd45be0 | 43 | #include <asm/sections.h> |
1da177e4 LT |
44 | #include <asm/cacheflush.h> |
45 | #include <asm/errno.h> | |
7c0f6ba6 | 46 | #include <linux/uaccess.h> |
1da177e4 LT |
47 | |
48 | #define KPROBE_HASH_BITS 6 | |
49 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
50 | ||
a737a3c6 XN |
51 | #if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL) |
52 | #define kprobe_sysctls_init() do { } while (0) | |
53 | #endif | |
3a872d89 | 54 | |
ef53d9c5 | 55 | static int kprobes_initialized; |
7e6a71d8 | 56 | /* kprobe_table can be accessed by |
223a76b2 | 57 | * - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held. |
7e6a71d8 MH |
58 | * Or |
59 | * - RCU hlist traversal under disabling preempt (breakpoint handlers) | |
60 | */ | |
1da177e4 LT |
61 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
62 | ||
223a76b2 | 63 | /* NOTE: change this value only with 'kprobe_mutex' held */ |
e579abeb | 64 | static bool kprobes_all_disarmed; |
bf8f6e5b | 65 | |
223a76b2 | 66 | /* This protects 'kprobe_table' and 'optimizing_list' */ |
43948f50 | 67 | static DEFINE_MUTEX(kprobe_mutex); |
223a76b2 | 68 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance); |
ef53d9c5 | 69 | |
290e3070 NR |
70 | kprobe_opcode_t * __weak kprobe_lookup_name(const char *name, |
71 | unsigned int __unused) | |
49e0b465 NR |
72 | { |
73 | return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); | |
74 | } | |
75 | ||
223a76b2 MH |
76 | /* |
77 | * Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where | |
78 | * kprobes can not probe. | |
79 | */ | |
376e2424 | 80 | static LIST_HEAD(kprobe_blacklist); |
3d8d996e | 81 | |
2d14e39d | 82 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 | 83 | /* |
223a76b2 | 84 | * 'kprobe::ainsn.insn' points to the copy of the instruction to be |
9ec4b1f3 AM |
85 | * single-stepped. x86_64, POWER4 and above have no-exec support and |
86 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
87 | * is a recipe for disaster | |
88 | */ | |
9ec4b1f3 | 89 | struct kprobe_insn_page { |
c5cb5a2d | 90 | struct list_head list; |
9ec4b1f3 | 91 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
af96397d | 92 | struct kprobe_insn_cache *cache; |
9ec4b1f3 | 93 | int nused; |
b4c6c34a | 94 | int ngarbage; |
4610ee1d | 95 | char slot_used[]; |
9ec4b1f3 AM |
96 | }; |
97 | ||
4610ee1d MH |
98 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
99 | (offsetof(struct kprobe_insn_page, slot_used) + \ | |
100 | (sizeof(char) * (slots))) | |
101 | ||
4610ee1d MH |
102 | static int slots_per_page(struct kprobe_insn_cache *c) |
103 | { | |
104 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
105 | } | |
106 | ||
ab40c5c6 MH |
107 | enum kprobe_slot_state { |
108 | SLOT_CLEAN = 0, | |
109 | SLOT_DIRTY = 1, | |
110 | SLOT_USED = 2, | |
111 | }; | |
112 | ||
63fef14f | 113 | void __weak *alloc_insn_page(void) |
af96397d | 114 | { |
223a76b2 MH |
115 | /* |
116 | * Use module_alloc() so this page is within +/- 2GB of where the | |
117 | * kernel image and loaded module images reside. This is required | |
118 | * for most of the architectures. | |
119 | * (e.g. x86-64 needs this to handle the %rip-relative fixups.) | |
120 | */ | |
af96397d HC |
121 | return module_alloc(PAGE_SIZE); |
122 | } | |
123 | ||
66ce7514 | 124 | static void free_insn_page(void *page) |
af96397d | 125 | { |
be1f221c | 126 | module_memfree(page); |
af96397d HC |
127 | } |
128 | ||
c802d64a HC |
129 | struct kprobe_insn_cache kprobe_insn_slots = { |
130 | .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), | |
af96397d HC |
131 | .alloc = alloc_insn_page, |
132 | .free = free_insn_page, | |
d002b8bc | 133 | .sym = KPROBE_INSN_PAGE_SYM, |
4610ee1d MH |
134 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
135 | .insn_size = MAX_INSN_SIZE, | |
136 | .nr_garbage = 0, | |
137 | }; | |
55479f64 | 138 | static int collect_garbage_slots(struct kprobe_insn_cache *c); |
b4c6c34a | 139 | |
9ec4b1f3 | 140 | /** |
12941560 | 141 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
142 | * We allocate an executable page if there's no room on existing ones. |
143 | */ | |
55479f64 | 144 | kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
145 | { |
146 | struct kprobe_insn_page *kip; | |
c802d64a | 147 | kprobe_opcode_t *slot = NULL; |
9ec4b1f3 | 148 | |
5b485629 | 149 | /* Since the slot array is not protected by rcu, we need a mutex */ |
c802d64a | 150 | mutex_lock(&c->mutex); |
6f716acd | 151 | retry: |
5b485629 MH |
152 | rcu_read_lock(); |
153 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
4610ee1d | 154 | if (kip->nused < slots_per_page(c)) { |
9ec4b1f3 | 155 | int i; |
223a76b2 | 156 | |
4610ee1d | 157 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
158 | if (kip->slot_used[i] == SLOT_CLEAN) { |
159 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 160 | kip->nused++; |
c802d64a | 161 | slot = kip->insns + (i * c->insn_size); |
5b485629 | 162 | rcu_read_unlock(); |
c802d64a | 163 | goto out; |
9ec4b1f3 AM |
164 | } |
165 | } | |
4610ee1d MH |
166 | /* kip->nused is broken. Fix it. */ |
167 | kip->nused = slots_per_page(c); | |
168 | WARN_ON(1); | |
9ec4b1f3 AM |
169 | } |
170 | } | |
5b485629 | 171 | rcu_read_unlock(); |
9ec4b1f3 | 172 | |
b4c6c34a | 173 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 174 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 175 | goto retry; |
4610ee1d MH |
176 | |
177 | /* All out of space. Need to allocate a new page. */ | |
178 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); | |
6f716acd | 179 | if (!kip) |
c802d64a | 180 | goto out; |
9ec4b1f3 | 181 | |
af96397d | 182 | kip->insns = c->alloc(); |
9ec4b1f3 AM |
183 | if (!kip->insns) { |
184 | kfree(kip); | |
c802d64a | 185 | goto out; |
9ec4b1f3 | 186 | } |
c5cb5a2d | 187 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 188 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 189 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 190 | kip->nused = 1; |
b4c6c34a | 191 | kip->ngarbage = 0; |
af96397d | 192 | kip->cache = c; |
5b485629 | 193 | list_add_rcu(&kip->list, &c->pages); |
c802d64a | 194 | slot = kip->insns; |
69e49088 AH |
195 | |
196 | /* Record the perf ksymbol register event after adding the page */ | |
197 | perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns, | |
198 | PAGE_SIZE, false, c->sym); | |
c802d64a HC |
199 | out: |
200 | mutex_unlock(&c->mutex); | |
201 | return slot; | |
12941560 MH |
202 | } |
203 | ||
29e8077a MH |
204 | /* Return true if all garbages are collected, otherwise false. */ |
205 | static bool collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
b4c6c34a | 206 | { |
ab40c5c6 | 207 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
208 | kip->nused--; |
209 | if (kip->nused == 0) { | |
210 | /* | |
211 | * Page is no longer in use. Free it unless | |
212 | * it's the last one. We keep the last one | |
213 | * so as not to have to set it up again the | |
214 | * next time somebody inserts a probe. | |
215 | */ | |
4610ee1d | 216 | if (!list_is_singular(&kip->list)) { |
69e49088 AH |
217 | /* |
218 | * Record perf ksymbol unregister event before removing | |
219 | * the page. | |
220 | */ | |
221 | perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, | |
222 | (unsigned long)kip->insns, PAGE_SIZE, true, | |
223 | kip->cache->sym); | |
5b485629 MH |
224 | list_del_rcu(&kip->list); |
225 | synchronize_rcu(); | |
af96397d | 226 | kip->cache->free(kip->insns); |
b4c6c34a MH |
227 | kfree(kip); |
228 | } | |
29e8077a | 229 | return true; |
b4c6c34a | 230 | } |
29e8077a | 231 | return false; |
b4c6c34a MH |
232 | } |
233 | ||
55479f64 | 234 | static int collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 235 | { |
c5cb5a2d | 236 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 237 | |
615d0ebb | 238 | /* Ensure no-one is interrupted on the garbages */ |
ae8b7ce7 | 239 | synchronize_rcu(); |
b4c6c34a | 240 | |
4610ee1d | 241 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 242 | int i; |
223a76b2 | 243 | |
b4c6c34a MH |
244 | if (kip->ngarbage == 0) |
245 | continue; | |
246 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 247 | for (i = 0; i < slots_per_page(c); i++) { |
5b485629 | 248 | if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i)) |
b4c6c34a MH |
249 | break; |
250 | } | |
251 | } | |
4610ee1d | 252 | c->nr_garbage = 0; |
b4c6c34a MH |
253 | return 0; |
254 | } | |
255 | ||
55479f64 MH |
256 | void __free_insn_slot(struct kprobe_insn_cache *c, |
257 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
258 | { |
259 | struct kprobe_insn_page *kip; | |
5b485629 | 260 | long idx; |
9ec4b1f3 | 261 | |
c802d64a | 262 | mutex_lock(&c->mutex); |
5b485629 MH |
263 | rcu_read_lock(); |
264 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
265 | idx = ((long)slot - (long)kip->insns) / | |
266 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
267 | if (idx >= 0 && idx < slots_per_page(c)) | |
c802d64a | 268 | goto out; |
9ec4b1f3 | 269 | } |
5b485629 | 270 | /* Could not find this slot. */ |
4610ee1d | 271 | WARN_ON(1); |
5b485629 | 272 | kip = NULL; |
c802d64a | 273 | out: |
5b485629 MH |
274 | rcu_read_unlock(); |
275 | /* Mark and sweep: this may sleep */ | |
276 | if (kip) { | |
277 | /* Check double free */ | |
278 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
279 | if (dirty) { | |
280 | kip->slot_used[idx] = SLOT_DIRTY; | |
281 | kip->ngarbage++; | |
282 | if (++c->nr_garbage > slots_per_page(c)) | |
283 | collect_garbage_slots(c); | |
284 | } else { | |
285 | collect_one_slot(kip, idx); | |
286 | } | |
287 | } | |
c802d64a | 288 | mutex_unlock(&c->mutex); |
4610ee1d | 289 | } |
6f716acd | 290 | |
5b485629 MH |
291 | /* |
292 | * Check given address is on the page of kprobe instruction slots. | |
293 | * This will be used for checking whether the address on a stack | |
294 | * is on a text area or not. | |
295 | */ | |
296 | bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr) | |
297 | { | |
298 | struct kprobe_insn_page *kip; | |
299 | bool ret = false; | |
300 | ||
301 | rcu_read_lock(); | |
302 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
303 | if (addr >= (unsigned long)kip->insns && | |
304 | addr < (unsigned long)kip->insns + PAGE_SIZE) { | |
305 | ret = true; | |
306 | break; | |
307 | } | |
308 | } | |
309 | rcu_read_unlock(); | |
310 | ||
311 | return ret; | |
312 | } | |
313 | ||
d002b8bc AH |
314 | int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum, |
315 | unsigned long *value, char *type, char *sym) | |
316 | { | |
317 | struct kprobe_insn_page *kip; | |
318 | int ret = -ERANGE; | |
319 | ||
320 | rcu_read_lock(); | |
321 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
322 | if ((*symnum)--) | |
323 | continue; | |
223a76b2 | 324 | strscpy(sym, c->sym, KSYM_NAME_LEN); |
d002b8bc AH |
325 | *type = 't'; |
326 | *value = (unsigned long)kip->insns; | |
327 | ret = 0; | |
328 | break; | |
329 | } | |
330 | rcu_read_unlock(); | |
331 | ||
332 | return ret; | |
333 | } | |
334 | ||
afd66255 | 335 | #ifdef CONFIG_OPTPROBES |
7ee3e97e CL |
336 | void __weak *alloc_optinsn_page(void) |
337 | { | |
338 | return alloc_insn_page(); | |
339 | } | |
340 | ||
341 | void __weak free_optinsn_page(void *page) | |
342 | { | |
343 | free_insn_page(page); | |
344 | } | |
345 | ||
afd66255 | 346 | /* For optimized_kprobe buffer */ |
c802d64a HC |
347 | struct kprobe_insn_cache kprobe_optinsn_slots = { |
348 | .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), | |
7ee3e97e CL |
349 | .alloc = alloc_optinsn_page, |
350 | .free = free_optinsn_page, | |
d002b8bc | 351 | .sym = KPROBE_OPTINSN_PAGE_SYM, |
afd66255 MH |
352 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
353 | /* .insn_size is initialized later */ | |
354 | .nr_garbage = 0, | |
355 | }; | |
afd66255 | 356 | #endif |
2d14e39d | 357 | #endif |
9ec4b1f3 | 358 | |
e6584523 AM |
359 | /* We have preemption disabled.. so it is safe to use __ versions */ |
360 | static inline void set_kprobe_instance(struct kprobe *kp) | |
361 | { | |
b76834bc | 362 | __this_cpu_write(kprobe_instance, kp); |
e6584523 AM |
363 | } |
364 | ||
365 | static inline void reset_kprobe_instance(void) | |
366 | { | |
b76834bc | 367 | __this_cpu_write(kprobe_instance, NULL); |
e6584523 AM |
368 | } |
369 | ||
3516a460 AM |
370 | /* |
371 | * This routine is called either: | |
223a76b2 MH |
372 | * - under the 'kprobe_mutex' - during kprobe_[un]register(). |
373 | * OR | |
374 | * - with preemption disabled - from architecture specific code. | |
3516a460 | 375 | */ |
820aede0 | 376 | struct kprobe *get_kprobe(void *addr) |
1da177e4 LT |
377 | { |
378 | struct hlist_head *head; | |
3516a460 | 379 | struct kprobe *p; |
1da177e4 LT |
380 | |
381 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
6743ad43 MH |
382 | hlist_for_each_entry_rcu(p, head, hlist, |
383 | lockdep_is_held(&kprobe_mutex)) { | |
1da177e4 LT |
384 | if (p->addr == addr) |
385 | return p; | |
386 | } | |
afd66255 | 387 | |
1da177e4 LT |
388 | return NULL; |
389 | } | |
820aede0 | 390 | NOKPROBE_SYMBOL(get_kprobe); |
1da177e4 | 391 | |
820aede0 | 392 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
afd66255 | 393 | |
223a76b2 | 394 | /* Return true if 'p' is an aggregator */ |
29e8077a | 395 | static inline bool kprobe_aggrprobe(struct kprobe *p) |
afd66255 MH |
396 | { |
397 | return p->pre_handler == aggr_pre_handler; | |
398 | } | |
399 | ||
223a76b2 | 400 | /* Return true if 'p' is unused */ |
29e8077a | 401 | static inline bool kprobe_unused(struct kprobe *p) |
6274de49 MH |
402 | { |
403 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && | |
404 | list_empty(&p->list); | |
405 | } | |
406 | ||
223a76b2 | 407 | /* Keep all fields in the kprobe consistent. */ |
6d8e40a8 | 408 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 409 | { |
6d8e40a8 MH |
410 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
411 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
412 | } |
413 | ||
414 | #ifdef CONFIG_OPTPROBES | |
223a76b2 | 415 | /* NOTE: This is protected by 'kprobe_mutex'. */ |
b2be84df MH |
416 | static bool kprobes_allow_optimization; |
417 | ||
afd66255 | 418 | /* |
223a76b2 | 419 | * Call all 'kprobe::pre_handler' on the list, but ignores its return value. |
afd66255 MH |
420 | * This must be called from arch-dep optimized caller. |
421 | */ | |
820aede0 | 422 | void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
afd66255 MH |
423 | { |
424 | struct kprobe *kp; | |
425 | ||
426 | list_for_each_entry_rcu(kp, &p->list, list) { | |
427 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
428 | set_kprobe_instance(kp); | |
4f3a8714 | 429 | kp->pre_handler(kp, regs); |
afd66255 MH |
430 | } |
431 | reset_kprobe_instance(); | |
432 | } | |
433 | } | |
820aede0 | 434 | NOKPROBE_SYMBOL(opt_pre_handler); |
afd66255 | 435 | |
6274de49 | 436 | /* Free optimized instructions and optimized_kprobe */ |
55479f64 | 437 | static void free_aggr_kprobe(struct kprobe *p) |
6274de49 MH |
438 | { |
439 | struct optimized_kprobe *op; | |
440 | ||
441 | op = container_of(p, struct optimized_kprobe, kp); | |
442 | arch_remove_optimized_kprobe(op); | |
443 | arch_remove_kprobe(p); | |
444 | kfree(op); | |
445 | } | |
446 | ||
223a76b2 | 447 | /* Return true if the kprobe is ready for optimization. */ |
afd66255 MH |
448 | static inline int kprobe_optready(struct kprobe *p) |
449 | { | |
450 | struct optimized_kprobe *op; | |
451 | ||
452 | if (kprobe_aggrprobe(p)) { | |
453 | op = container_of(p, struct optimized_kprobe, kp); | |
454 | return arch_prepared_optinsn(&op->optinsn); | |
455 | } | |
456 | ||
457 | return 0; | |
458 | } | |
459 | ||
223a76b2 | 460 | /* Return true if the kprobe is disarmed. Note: p must be on hash list */ |
29e8077a | 461 | static inline bool kprobe_disarmed(struct kprobe *p) |
6274de49 MH |
462 | { |
463 | struct optimized_kprobe *op; | |
464 | ||
465 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ | |
466 | if (!kprobe_aggrprobe(p)) | |
467 | return kprobe_disabled(p); | |
468 | ||
469 | op = container_of(p, struct optimized_kprobe, kp); | |
470 | ||
471 | return kprobe_disabled(p) && list_empty(&op->list); | |
472 | } | |
473 | ||
223a76b2 | 474 | /* Return true if the probe is queued on (un)optimizing lists */ |
29e8077a | 475 | static bool kprobe_queued(struct kprobe *p) |
6274de49 MH |
476 | { |
477 | struct optimized_kprobe *op; | |
478 | ||
479 | if (kprobe_aggrprobe(p)) { | |
480 | op = container_of(p, struct optimized_kprobe, kp); | |
481 | if (!list_empty(&op->list)) | |
29e8077a | 482 | return true; |
6274de49 | 483 | } |
29e8077a | 484 | return false; |
6274de49 MH |
485 | } |
486 | ||
afd66255 MH |
487 | /* |
488 | * Return an optimized kprobe whose optimizing code replaces | |
223a76b2 | 489 | * instructions including 'addr' (exclude breakpoint). |
afd66255 | 490 | */ |
c42421e2 | 491 | static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr) |
afd66255 MH |
492 | { |
493 | int i; | |
494 | struct kprobe *p = NULL; | |
495 | struct optimized_kprobe *op; | |
496 | ||
497 | /* Don't check i == 0, since that is a breakpoint case. */ | |
c42421e2 MH |
498 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) |
499 | p = get_kprobe(addr - i); | |
afd66255 MH |
500 | |
501 | if (p && kprobe_optready(p)) { | |
502 | op = container_of(p, struct optimized_kprobe, kp); | |
503 | if (arch_within_optimized_kprobe(op, addr)) | |
504 | return p; | |
505 | } | |
506 | ||
507 | return NULL; | |
508 | } | |
509 | ||
223a76b2 | 510 | /* Optimization staging list, protected by 'kprobe_mutex' */ |
afd66255 | 511 | static LIST_HEAD(optimizing_list); |
6274de49 | 512 | static LIST_HEAD(unoptimizing_list); |
7b959fc5 | 513 | static LIST_HEAD(freeing_list); |
afd66255 MH |
514 | |
515 | static void kprobe_optimizer(struct work_struct *work); | |
516 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
517 | #define OPTIMIZE_DELAY 5 | |
518 | ||
61f4e13f MH |
519 | /* |
520 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
223a76b2 | 521 | * 'optimizing_list'. |
61f4e13f | 522 | */ |
55479f64 | 523 | static void do_optimize_kprobes(void) |
afd66255 | 524 | { |
f1c6ece2 | 525 | lockdep_assert_held(&text_mutex); |
afd66255 | 526 | /* |
223a76b2 MH |
527 | * The optimization/unoptimization refers 'online_cpus' via |
528 | * stop_machine() and cpu-hotplug modifies the 'online_cpus'. | |
529 | * And same time, 'text_mutex' will be held in cpu-hotplug and here. | |
530 | * This combination can cause a deadlock (cpu-hotplug tries to lock | |
531 | * 'text_mutex' but stop_machine() can not be done because | |
532 | * the 'online_cpus' has been changed) | |
533 | * To avoid this deadlock, caller must have locked cpu-hotplug | |
534 | * for preventing cpu-hotplug outside of 'text_mutex' locking. | |
afd66255 | 535 | */ |
2d1e38f5 TG |
536 | lockdep_assert_cpus_held(); |
537 | ||
538 | /* Optimization never be done when disarmed */ | |
539 | if (kprobes_all_disarmed || !kprobes_allow_optimization || | |
540 | list_empty(&optimizing_list)) | |
541 | return; | |
542 | ||
cd7ebe22 | 543 | arch_optimize_kprobes(&optimizing_list); |
61f4e13f MH |
544 | } |
545 | ||
6274de49 MH |
546 | /* |
547 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint | |
223a76b2 | 548 | * if need) kprobes listed on 'unoptimizing_list'. |
6274de49 | 549 | */ |
55479f64 | 550 | static void do_unoptimize_kprobes(void) |
6274de49 MH |
551 | { |
552 | struct optimized_kprobe *op, *tmp; | |
553 | ||
f1c6ece2 | 554 | lockdep_assert_held(&text_mutex); |
2d1e38f5 TG |
555 | /* See comment in do_optimize_kprobes() */ |
556 | lockdep_assert_cpus_held(); | |
557 | ||
6274de49 MH |
558 | /* Unoptimization must be done anytime */ |
559 | if (list_empty(&unoptimizing_list)) | |
560 | return; | |
561 | ||
7b959fc5 | 562 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
223a76b2 | 563 | /* Loop on 'freeing_list' for disarming */ |
7b959fc5 | 564 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
f66c0447 MH |
565 | /* Switching from detour code to origin */ |
566 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
6274de49 MH |
567 | /* Disarm probes if marked disabled */ |
568 | if (kprobe_disabled(&op->kp)) | |
569 | arch_disarm_kprobe(&op->kp); | |
570 | if (kprobe_unused(&op->kp)) { | |
571 | /* | |
572 | * Remove unused probes from hash list. After waiting | |
573 | * for synchronization, these probes are reclaimed. | |
223a76b2 | 574 | * (reclaiming is done by do_free_cleaned_kprobes().) |
6274de49 MH |
575 | */ |
576 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
577 | } else |
578 | list_del_init(&op->list); | |
579 | } | |
6274de49 MH |
580 | } |
581 | ||
223a76b2 | 582 | /* Reclaim all kprobes on the 'freeing_list' */ |
55479f64 | 583 | static void do_free_cleaned_kprobes(void) |
6274de49 MH |
584 | { |
585 | struct optimized_kprobe *op, *tmp; | |
586 | ||
7b959fc5 | 587 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 | 588 | list_del_init(&op->list); |
cbdd96f5 MH |
589 | if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) { |
590 | /* | |
591 | * This must not happen, but if there is a kprobe | |
592 | * still in use, keep it on kprobes hash list. | |
593 | */ | |
594 | continue; | |
595 | } | |
6274de49 MH |
596 | free_aggr_kprobe(&op->kp); |
597 | } | |
598 | } | |
599 | ||
600 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
55479f64 | 601 | static void kick_kprobe_optimizer(void) |
6274de49 | 602 | { |
ad72b3be | 603 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de49 MH |
604 | } |
605 | ||
61f4e13f | 606 | /* Kprobe jump optimizer */ |
55479f64 | 607 | static void kprobe_optimizer(struct work_struct *work) |
61f4e13f | 608 | { |
72ef3794 | 609 | mutex_lock(&kprobe_mutex); |
2d1e38f5 | 610 | cpus_read_lock(); |
f1c6ece2 | 611 | mutex_lock(&text_mutex); |
61f4e13f MH |
612 | |
613 | /* | |
6274de49 MH |
614 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
615 | * kprobes before waiting for quiesence period. | |
616 | */ | |
7b959fc5 | 617 | do_unoptimize_kprobes(); |
6274de49 MH |
618 | |
619 | /* | |
a30b85df MH |
620 | * Step 2: Wait for quiesence period to ensure all potentially |
621 | * preempted tasks to have normally scheduled. Because optprobe | |
622 | * may modify multiple instructions, there is a chance that Nth | |
623 | * instruction is preempted. In that case, such tasks can return | |
624 | * to 2nd-Nth byte of jump instruction. This wait is for avoiding it. | |
625 | * Note that on non-preemptive kernel, this is transparently converted | |
626 | * to synchronoze_sched() to wait for all interrupts to have completed. | |
61f4e13f | 627 | */ |
a30b85df | 628 | synchronize_rcu_tasks(); |
61f4e13f | 629 | |
6274de49 | 630 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 631 | do_optimize_kprobes(); |
6274de49 MH |
632 | |
633 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
7b959fc5 | 634 | do_free_cleaned_kprobes(); |
6274de49 | 635 | |
f1c6ece2 | 636 | mutex_unlock(&text_mutex); |
2d1e38f5 | 637 | cpus_read_unlock(); |
6274de49 | 638 | |
cd7ebe22 | 639 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 640 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 | 641 | kick_kprobe_optimizer(); |
1a0aa991 MH |
642 | |
643 | mutex_unlock(&kprobe_mutex); | |
6274de49 MH |
644 | } |
645 | ||
646 | /* Wait for completing optimization and unoptimization */ | |
30e7d894 | 647 | void wait_for_kprobe_optimizer(void) |
6274de49 | 648 | { |
ad72b3be TH |
649 | mutex_lock(&kprobe_mutex); |
650 | ||
651 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { | |
652 | mutex_unlock(&kprobe_mutex); | |
653 | ||
223a76b2 | 654 | /* This will also make 'optimizing_work' execute immmediately */ |
ad72b3be | 655 | flush_delayed_work(&optimizing_work); |
223a76b2 | 656 | /* 'optimizing_work' might not have been queued yet, relax */ |
ad72b3be TH |
657 | cpu_relax(); |
658 | ||
659 | mutex_lock(&kprobe_mutex); | |
660 | } | |
661 | ||
662 | mutex_unlock(&kprobe_mutex); | |
afd66255 MH |
663 | } |
664 | ||
e4add247 MH |
665 | static bool optprobe_queued_unopt(struct optimized_kprobe *op) |
666 | { | |
667 | struct optimized_kprobe *_op; | |
668 | ||
669 | list_for_each_entry(_op, &unoptimizing_list, list) { | |
670 | if (op == _op) | |
671 | return true; | |
672 | } | |
673 | ||
674 | return false; | |
675 | } | |
676 | ||
afd66255 | 677 | /* Optimize kprobe if p is ready to be optimized */ |
55479f64 | 678 | static void optimize_kprobe(struct kprobe *p) |
afd66255 MH |
679 | { |
680 | struct optimized_kprobe *op; | |
681 | ||
682 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 683 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
684 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
685 | return; | |
686 | ||
223a76b2 | 687 | /* kprobes with 'post_handler' can not be optimized */ |
059053a2 | 688 | if (p->post_handler) |
afd66255 MH |
689 | return; |
690 | ||
691 | op = container_of(p, struct optimized_kprobe, kp); | |
692 | ||
693 | /* Check there is no other kprobes at the optimized instructions */ | |
694 | if (arch_check_optimized_kprobe(op) < 0) | |
695 | return; | |
696 | ||
697 | /* Check if it is already optimized. */ | |
e4add247 MH |
698 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) { |
699 | if (optprobe_queued_unopt(op)) { | |
700 | /* This is under unoptimizing. Just dequeue the probe */ | |
701 | list_del_init(&op->list); | |
702 | } | |
afd66255 | 703 | return; |
e4add247 | 704 | } |
afd66255 | 705 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 | 706 | |
223a76b2 MH |
707 | /* |
708 | * On the 'unoptimizing_list' and 'optimizing_list', | |
709 | * 'op' must have OPTIMIZED flag | |
710 | */ | |
e4add247 MH |
711 | if (WARN_ON_ONCE(!list_empty(&op->list))) |
712 | return; | |
713 | ||
714 | list_add(&op->list, &optimizing_list); | |
715 | kick_kprobe_optimizer(); | |
6274de49 MH |
716 | } |
717 | ||
718 | /* Short cut to direct unoptimizing */ | |
55479f64 | 719 | static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
6274de49 | 720 | { |
2d1e38f5 | 721 | lockdep_assert_cpus_held(); |
6274de49 | 722 | arch_unoptimize_kprobe(op); |
f66c0447 | 723 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
afd66255 MH |
724 | } |
725 | ||
726 | /* Unoptimize a kprobe if p is optimized */ | |
55479f64 | 727 | static void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
728 | { |
729 | struct optimized_kprobe *op; | |
730 | ||
6274de49 MH |
731 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
732 | return; /* This is not an optprobe nor optimized */ | |
733 | ||
734 | op = container_of(p, struct optimized_kprobe, kp); | |
e4add247 | 735 | if (!kprobe_optimized(p)) |
6274de49 | 736 | return; |
6274de49 | 737 | |
6274de49 | 738 | if (!list_empty(&op->list)) { |
e4add247 MH |
739 | if (optprobe_queued_unopt(op)) { |
740 | /* Queued in unoptimizing queue */ | |
741 | if (force) { | |
742 | /* | |
743 | * Forcibly unoptimize the kprobe here, and queue it | |
744 | * in the freeing list for release afterwards. | |
745 | */ | |
746 | force_unoptimize_kprobe(op); | |
747 | list_move(&op->list, &freeing_list); | |
748 | } | |
749 | } else { | |
750 | /* Dequeue from the optimizing queue */ | |
751 | list_del_init(&op->list); | |
752 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
753 | } | |
6274de49 MH |
754 | return; |
755 | } | |
e4add247 | 756 | |
6274de49 | 757 | /* Optimized kprobe case */ |
e4add247 | 758 | if (force) { |
6274de49 MH |
759 | /* Forcibly update the code: this is a special case */ |
760 | force_unoptimize_kprobe(op); | |
e4add247 | 761 | } else { |
6274de49 MH |
762 | list_add(&op->list, &unoptimizing_list); |
763 | kick_kprobe_optimizer(); | |
afd66255 MH |
764 | } |
765 | } | |
766 | ||
0490cd1f | 767 | /* Cancel unoptimizing for reusing */ |
819319fc | 768 | static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f MH |
769 | { |
770 | struct optimized_kprobe *op; | |
771 | ||
0490cd1f MH |
772 | /* |
773 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
774 | * there is still a relative jump) and disabled. | |
775 | */ | |
776 | op = container_of(ap, struct optimized_kprobe, kp); | |
4458515b | 777 | WARN_ON_ONCE(list_empty(&op->list)); |
0490cd1f MH |
778 | /* Enable the probe again */ |
779 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
223a76b2 | 780 | /* Optimize it again. (remove from 'op->list') */ |
5f843ed4 MH |
781 | if (!kprobe_optready(ap)) |
782 | return -EINVAL; | |
819319fc | 783 | |
0490cd1f | 784 | optimize_kprobe(ap); |
819319fc | 785 | return 0; |
0490cd1f MH |
786 | } |
787 | ||
afd66255 | 788 | /* Remove optimized instructions */ |
55479f64 | 789 | static void kill_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
790 | { |
791 | struct optimized_kprobe *op; | |
792 | ||
793 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
794 | if (!list_empty(&op->list)) |
795 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 796 | list_del_init(&op->list); |
6274de49 | 797 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc5 MH |
798 | |
799 | if (kprobe_unused(p)) { | |
800 | /* Enqueue if it is unused */ | |
801 | list_add(&op->list, &freeing_list); | |
802 | /* | |
803 | * Remove unused probes from the hash list. After waiting | |
804 | * for synchronization, this probe is reclaimed. | |
805 | * (reclaiming is done by do_free_cleaned_kprobes().) | |
806 | */ | |
807 | hlist_del_rcu(&op->kp.hlist); | |
808 | } | |
809 | ||
6274de49 | 810 | /* Don't touch the code, because it is already freed. */ |
afd66255 MH |
811 | arch_remove_optimized_kprobe(op); |
812 | } | |
813 | ||
a460246c MH |
814 | static inline |
815 | void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) | |
816 | { | |
817 | if (!kprobe_ftrace(p)) | |
818 | arch_prepare_optimized_kprobe(op, p); | |
819 | } | |
820 | ||
afd66255 | 821 | /* Try to prepare optimized instructions */ |
55479f64 | 822 | static void prepare_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
823 | { |
824 | struct optimized_kprobe *op; | |
825 | ||
826 | op = container_of(p, struct optimized_kprobe, kp); | |
a460246c | 827 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
828 | } |
829 | ||
223a76b2 | 830 | /* Allocate new optimized_kprobe and try to prepare optimized instructions. */ |
55479f64 | 831 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
832 | { |
833 | struct optimized_kprobe *op; | |
834 | ||
835 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
836 | if (!op) | |
837 | return NULL; | |
838 | ||
839 | INIT_LIST_HEAD(&op->list); | |
840 | op->kp.addr = p->addr; | |
a460246c | 841 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
842 | |
843 | return &op->kp; | |
844 | } | |
845 | ||
55479f64 | 846 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
afd66255 MH |
847 | |
848 | /* | |
223a76b2 MH |
849 | * Prepare an optimized_kprobe and optimize it. |
850 | * NOTE: 'p' must be a normal registered kprobe. | |
afd66255 | 851 | */ |
55479f64 | 852 | static void try_to_optimize_kprobe(struct kprobe *p) |
afd66255 MH |
853 | { |
854 | struct kprobe *ap; | |
855 | struct optimized_kprobe *op; | |
856 | ||
223a76b2 | 857 | /* Impossible to optimize ftrace-based kprobe. */ |
ae6aa16f MH |
858 | if (kprobe_ftrace(p)) |
859 | return; | |
860 | ||
223a76b2 | 861 | /* For preparing optimization, jump_label_text_reserved() is called. */ |
2d1e38f5 | 862 | cpus_read_lock(); |
25764288 MH |
863 | jump_label_lock(); |
864 | mutex_lock(&text_mutex); | |
865 | ||
afd66255 MH |
866 | ap = alloc_aggr_kprobe(p); |
867 | if (!ap) | |
25764288 | 868 | goto out; |
afd66255 MH |
869 | |
870 | op = container_of(ap, struct optimized_kprobe, kp); | |
871 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
223a76b2 | 872 | /* If failed to setup optimizing, fallback to kprobe. */ |
6274de49 MH |
873 | arch_remove_optimized_kprobe(op); |
874 | kfree(op); | |
25764288 | 875 | goto out; |
afd66255 MH |
876 | } |
877 | ||
878 | init_aggr_kprobe(ap, p); | |
223a76b2 | 879 | optimize_kprobe(ap); /* This just kicks optimizer thread. */ |
25764288 MH |
880 | |
881 | out: | |
882 | mutex_unlock(&text_mutex); | |
883 | jump_label_unlock(); | |
2d1e38f5 | 884 | cpus_read_unlock(); |
afd66255 MH |
885 | } |
886 | ||
55479f64 | 887 | static void optimize_all_kprobes(void) |
b2be84df MH |
888 | { |
889 | struct hlist_head *head; | |
b2be84df MH |
890 | struct kprobe *p; |
891 | unsigned int i; | |
892 | ||
5c51543b | 893 | mutex_lock(&kprobe_mutex); |
223a76b2 | 894 | /* If optimization is already allowed, just return. */ |
b2be84df | 895 | if (kprobes_allow_optimization) |
5c51543b | 896 | goto out; |
b2be84df | 897 | |
2d1e38f5 | 898 | cpus_read_lock(); |
b2be84df | 899 | kprobes_allow_optimization = true; |
b2be84df MH |
900 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
901 | head = &kprobe_table[i]; | |
7e6a71d8 | 902 | hlist_for_each_entry(p, head, hlist) |
b2be84df MH |
903 | if (!kprobe_disabled(p)) |
904 | optimize_kprobe(p); | |
905 | } | |
2d1e38f5 | 906 | cpus_read_unlock(); |
9c89bb8e | 907 | pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n"); |
5c51543b MH |
908 | out: |
909 | mutex_unlock(&kprobe_mutex); | |
b2be84df MH |
910 | } |
911 | ||
c85c9a2c | 912 | #ifdef CONFIG_SYSCTL |
55479f64 | 913 | static void unoptimize_all_kprobes(void) |
b2be84df MH |
914 | { |
915 | struct hlist_head *head; | |
b2be84df MH |
916 | struct kprobe *p; |
917 | unsigned int i; | |
918 | ||
5c51543b | 919 | mutex_lock(&kprobe_mutex); |
223a76b2 | 920 | /* If optimization is already prohibited, just return. */ |
5c51543b MH |
921 | if (!kprobes_allow_optimization) { |
922 | mutex_unlock(&kprobe_mutex); | |
b2be84df | 923 | return; |
5c51543b | 924 | } |
b2be84df | 925 | |
2d1e38f5 | 926 | cpus_read_lock(); |
b2be84df | 927 | kprobes_allow_optimization = false; |
b2be84df MH |
928 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
929 | head = &kprobe_table[i]; | |
7e6a71d8 | 930 | hlist_for_each_entry(p, head, hlist) { |
b2be84df | 931 | if (!kprobe_disabled(p)) |
6274de49 | 932 | unoptimize_kprobe(p, false); |
b2be84df MH |
933 | } |
934 | } | |
2d1e38f5 | 935 | cpus_read_unlock(); |
5c51543b MH |
936 | mutex_unlock(&kprobe_mutex); |
937 | ||
223a76b2 | 938 | /* Wait for unoptimizing completion. */ |
6274de49 | 939 | wait_for_kprobe_optimizer(); |
9c89bb8e | 940 | pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n"); |
b2be84df MH |
941 | } |
942 | ||
5c51543b | 943 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
a737a3c6 XN |
944 | static int sysctl_kprobes_optimization; |
945 | static int proc_kprobes_optimization_handler(struct ctl_table *table, | |
946 | int write, void *buffer, | |
947 | size_t *length, loff_t *ppos) | |
b2be84df MH |
948 | { |
949 | int ret; | |
950 | ||
5c51543b | 951 | mutex_lock(&kprobe_sysctl_mutex); |
b2be84df MH |
952 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
953 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
954 | ||
955 | if (sysctl_kprobes_optimization) | |
956 | optimize_all_kprobes(); | |
957 | else | |
958 | unoptimize_all_kprobes(); | |
5c51543b | 959 | mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df MH |
960 | |
961 | return ret; | |
962 | } | |
a737a3c6 XN |
963 | |
964 | static struct ctl_table kprobe_sysctls[] = { | |
965 | { | |
966 | .procname = "kprobes-optimization", | |
967 | .data = &sysctl_kprobes_optimization, | |
968 | .maxlen = sizeof(int), | |
969 | .mode = 0644, | |
970 | .proc_handler = proc_kprobes_optimization_handler, | |
971 | .extra1 = SYSCTL_ZERO, | |
972 | .extra2 = SYSCTL_ONE, | |
973 | }, | |
974 | {} | |
975 | }; | |
976 | ||
977 | static void __init kprobe_sysctls_init(void) | |
978 | { | |
979 | register_sysctl_init("debug", kprobe_sysctls); | |
980 | } | |
b2be84df MH |
981 | #endif /* CONFIG_SYSCTL */ |
982 | ||
57d4e317 | 983 | /* Put a breakpoint for a probe. */ |
55479f64 | 984 | static void __arm_kprobe(struct kprobe *p) |
afd66255 | 985 | { |
6d8e40a8 | 986 | struct kprobe *_p; |
afd66255 | 987 | |
57d4e317 MH |
988 | lockdep_assert_held(&text_mutex); |
989 | ||
223a76b2 | 990 | /* Find the overlapping optimized kprobes. */ |
c42421e2 | 991 | _p = get_optimized_kprobe(p->addr); |
6d8e40a8 | 992 | if (unlikely(_p)) |
6274de49 MH |
993 | /* Fallback to unoptimized kprobe */ |
994 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
995 | |
996 | arch_arm_kprobe(p); | |
997 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
998 | } | |
999 | ||
57d4e317 | 1000 | /* Remove the breakpoint of a probe. */ |
55479f64 | 1001 | static void __disarm_kprobe(struct kprobe *p, bool reopt) |
afd66255 | 1002 | { |
6d8e40a8 | 1003 | struct kprobe *_p; |
afd66255 | 1004 | |
57d4e317 MH |
1005 | lockdep_assert_held(&text_mutex); |
1006 | ||
69d54b91 WN |
1007 | /* Try to unoptimize */ |
1008 | unoptimize_kprobe(p, kprobes_all_disarmed); | |
afd66255 | 1009 | |
6274de49 MH |
1010 | if (!kprobe_queued(p)) { |
1011 | arch_disarm_kprobe(p); | |
223a76b2 | 1012 | /* If another kprobe was blocked, re-optimize it. */ |
c42421e2 | 1013 | _p = get_optimized_kprobe(p->addr); |
6274de49 MH |
1014 | if (unlikely(_p) && reopt) |
1015 | optimize_kprobe(_p); | |
1016 | } | |
223a76b2 MH |
1017 | /* |
1018 | * TODO: Since unoptimization and real disarming will be done by | |
1019 | * the worker thread, we can not check whether another probe are | |
1020 | * unoptimized because of this probe here. It should be re-optimized | |
1021 | * by the worker thread. | |
1022 | */ | |
afd66255 MH |
1023 | } |
1024 | ||
1025 | #else /* !CONFIG_OPTPROBES */ | |
1026 | ||
1027 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 1028 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
1029 | #define kill_optimized_kprobe(p) do {} while (0) |
1030 | #define prepare_optimized_kprobe(p) do {} while (0) | |
1031 | #define try_to_optimize_kprobe(p) do {} while (0) | |
1032 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
1033 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
1034 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
1035 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 1036 | |
819319fc | 1037 | static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f | 1038 | { |
819319fc MH |
1039 | /* |
1040 | * If the optimized kprobe is NOT supported, the aggr kprobe is | |
1041 | * released at the same time that the last aggregated kprobe is | |
1042 | * unregistered. | |
1043 | * Thus there should be no chance to reuse unused kprobe. | |
1044 | */ | |
9c89bb8e | 1045 | WARN_ON_ONCE(1); |
819319fc | 1046 | return -EINVAL; |
0490cd1f MH |
1047 | } |
1048 | ||
55479f64 | 1049 | static void free_aggr_kprobe(struct kprobe *p) |
afd66255 | 1050 | { |
6274de49 | 1051 | arch_remove_kprobe(p); |
afd66255 MH |
1052 | kfree(p); |
1053 | } | |
1054 | ||
55479f64 | 1055 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
1056 | { |
1057 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
1058 | } | |
1059 | #endif /* CONFIG_OPTPROBES */ | |
1060 | ||
e7dbfe34 | 1061 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 1062 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
0bc11ed5 MH |
1063 | .func = kprobe_ftrace_handler, |
1064 | .flags = FTRACE_OPS_FL_SAVE_REGS, | |
1065 | }; | |
1066 | ||
1067 | static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = { | |
e5253896 | 1068 | .func = kprobe_ftrace_handler, |
1d70be34 | 1069 | .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
ae6aa16f | 1070 | }; |
0bc11ed5 MH |
1071 | |
1072 | static int kprobe_ipmodify_enabled; | |
ae6aa16f MH |
1073 | static int kprobe_ftrace_enabled; |
1074 | ||
0bc11ed5 MH |
1075 | static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
1076 | int *cnt) | |
ae6aa16f | 1077 | { |
12310e34 | 1078 | int ret = 0; |
ae6aa16f | 1079 | |
57d4e317 MH |
1080 | lockdep_assert_held(&kprobe_mutex); |
1081 | ||
0bc11ed5 | 1082 | ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); |
9c89bb8e | 1083 | if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret)) |
12310e34 | 1084 | return ret; |
12310e34 | 1085 | |
0bc11ed5 MH |
1086 | if (*cnt == 0) { |
1087 | ret = register_ftrace_function(ops); | |
9c89bb8e | 1088 | if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret)) |
12310e34 | 1089 | goto err_ftrace; |
ae6aa16f | 1090 | } |
12310e34 | 1091 | |
0bc11ed5 | 1092 | (*cnt)++; |
12310e34 JY |
1093 | return ret; |
1094 | ||
1095 | err_ftrace: | |
1096 | /* | |
0bc11ed5 MH |
1097 | * At this point, sinec ops is not registered, we should be sefe from |
1098 | * registering empty filter. | |
12310e34 | 1099 | */ |
0bc11ed5 | 1100 | ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
12310e34 | 1101 | return ret; |
ae6aa16f MH |
1102 | } |
1103 | ||
0bc11ed5 MH |
1104 | static int arm_kprobe_ftrace(struct kprobe *p) |
1105 | { | |
1106 | bool ipmodify = (p->post_handler != NULL); | |
1107 | ||
1108 | return __arm_kprobe_ftrace(p, | |
1109 | ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, | |
1110 | ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); | |
1111 | } | |
1112 | ||
0bc11ed5 MH |
1113 | static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
1114 | int *cnt) | |
ae6aa16f | 1115 | { |
297f9233 | 1116 | int ret = 0; |
ae6aa16f | 1117 | |
57d4e317 MH |
1118 | lockdep_assert_held(&kprobe_mutex); |
1119 | ||
0bc11ed5 MH |
1120 | if (*cnt == 1) { |
1121 | ret = unregister_ftrace_function(ops); | |
9c89bb8e | 1122 | if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret)) |
297f9233 | 1123 | return ret; |
ae6aa16f | 1124 | } |
297f9233 | 1125 | |
0bc11ed5 | 1126 | (*cnt)--; |
297f9233 | 1127 | |
0bc11ed5 | 1128 | ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
9c89bb8e | 1129 | WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n", |
4458515b | 1130 | p->addr, ret); |
297f9233 | 1131 | return ret; |
ae6aa16f | 1132 | } |
0bc11ed5 MH |
1133 | |
1134 | static int disarm_kprobe_ftrace(struct kprobe *p) | |
1135 | { | |
1136 | bool ipmodify = (p->post_handler != NULL); | |
1137 | ||
1138 | return __disarm_kprobe_ftrace(p, | |
1139 | ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, | |
1140 | ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); | |
1141 | } | |
e7dbfe34 | 1142 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
10de795a MS |
1143 | static inline int arm_kprobe_ftrace(struct kprobe *p) |
1144 | { | |
1145 | return -ENODEV; | |
1146 | } | |
1147 | ||
1148 | static inline int disarm_kprobe_ftrace(struct kprobe *p) | |
1149 | { | |
1150 | return -ENODEV; | |
1151 | } | |
ae6aa16f MH |
1152 | #endif |
1153 | ||
02afb8d6 PA |
1154 | static int prepare_kprobe(struct kprobe *p) |
1155 | { | |
1156 | /* Must ensure p->addr is really on ftrace */ | |
1157 | if (kprobe_ftrace(p)) | |
1158 | return arch_prepare_kprobe_ftrace(p); | |
1159 | ||
1160 | return arch_prepare_kprobe(p); | |
1161 | } | |
1162 | ||
12310e34 | 1163 | static int arm_kprobe(struct kprobe *kp) |
201517a7 | 1164 | { |
12310e34 JY |
1165 | if (unlikely(kprobe_ftrace(kp))) |
1166 | return arm_kprobe_ftrace(kp); | |
1167 | ||
2d1e38f5 | 1168 | cpus_read_lock(); |
201517a7 | 1169 | mutex_lock(&text_mutex); |
afd66255 | 1170 | __arm_kprobe(kp); |
201517a7 | 1171 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1172 | cpus_read_unlock(); |
12310e34 JY |
1173 | |
1174 | return 0; | |
201517a7 MH |
1175 | } |
1176 | ||
297f9233 | 1177 | static int disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 1178 | { |
297f9233 JY |
1179 | if (unlikely(kprobe_ftrace(kp))) |
1180 | return disarm_kprobe_ftrace(kp); | |
2d1e38f5 TG |
1181 | |
1182 | cpus_read_lock(); | |
201517a7 | 1183 | mutex_lock(&text_mutex); |
ae6aa16f | 1184 | __disarm_kprobe(kp, reopt); |
201517a7 | 1185 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1186 | cpus_read_unlock(); |
297f9233 JY |
1187 | |
1188 | return 0; | |
201517a7 MH |
1189 | } |
1190 | ||
64f562c6 AM |
1191 | /* |
1192 | * Aggregate handlers for multiple kprobes support - these handlers | |
1193 | * take care of invoking the individual kprobe handlers on p->list | |
1194 | */ | |
820aede0 | 1195 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
1196 | { |
1197 | struct kprobe *kp; | |
1198 | ||
3516a460 | 1199 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1200 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1201 | set_kprobe_instance(kp); |
8b0914ea PP |
1202 | if (kp->pre_handler(kp, regs)) |
1203 | return 1; | |
64f562c6 | 1204 | } |
e6584523 | 1205 | reset_kprobe_instance(); |
64f562c6 AM |
1206 | } |
1207 | return 0; | |
1208 | } | |
820aede0 | 1209 | NOKPROBE_SYMBOL(aggr_pre_handler); |
64f562c6 | 1210 | |
820aede0 MH |
1211 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1212 | unsigned long flags) | |
64f562c6 AM |
1213 | { |
1214 | struct kprobe *kp; | |
1215 | ||
3516a460 | 1216 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1217 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1218 | set_kprobe_instance(kp); |
64f562c6 | 1219 | kp->post_handler(kp, regs, flags); |
e6584523 | 1220 | reset_kprobe_instance(); |
64f562c6 AM |
1221 | } |
1222 | } | |
64f562c6 | 1223 | } |
820aede0 | 1224 | NOKPROBE_SYMBOL(aggr_post_handler); |
64f562c6 | 1225 | |
223a76b2 | 1226 | /* Walks the list and increments 'nmissed' if 'p' has child probes. */ |
820aede0 | 1227 | void kprobes_inc_nmissed_count(struct kprobe *p) |
bf8d5c52 KA |
1228 | { |
1229 | struct kprobe *kp; | |
223a76b2 | 1230 | |
afd66255 | 1231 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1232 | p->nmissed++; |
1233 | } else { | |
1234 | list_for_each_entry_rcu(kp, &p->list, list) | |
1235 | kp->nmissed++; | |
1236 | } | |
bf8d5c52 | 1237 | } |
820aede0 | 1238 | NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
bf8d5c52 | 1239 | |
d741bf41 PZ |
1240 | static void free_rp_inst_rcu(struct rcu_head *head) |
1241 | { | |
1242 | struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu); | |
1243 | ||
1244 | if (refcount_dec_and_test(&ri->rph->ref)) | |
1245 | kfree(ri->rph); | |
1246 | kfree(ri); | |
1247 | } | |
1248 | NOKPROBE_SYMBOL(free_rp_inst_rcu); | |
1249 | ||
b3388178 | 1250 | static void recycle_rp_inst(struct kretprobe_instance *ri) |
b94cce92 | 1251 | { |
d741bf41 | 1252 | struct kretprobe *rp = get_kretprobe(ri); |
ef53d9c5 | 1253 | |
223a76b2 | 1254 | if (likely(rp)) |
6e426e0f | 1255 | freelist_add(&ri->freelist, &rp->freelist); |
223a76b2 | 1256 | else |
d741bf41 | 1257 | call_rcu(&ri->rcu, free_rp_inst_rcu); |
b94cce92 | 1258 | } |
820aede0 | 1259 | NOKPROBE_SYMBOL(recycle_rp_inst); |
b94cce92 | 1260 | |
319f0ce2 | 1261 | static struct kprobe kprobe_busy = { |
9b38cc70 JO |
1262 | .addr = (void *) get_kprobe, |
1263 | }; | |
1264 | ||
1265 | void kprobe_busy_begin(void) | |
1266 | { | |
1267 | struct kprobe_ctlblk *kcb; | |
1268 | ||
1269 | preempt_disable(); | |
1270 | __this_cpu_write(current_kprobe, &kprobe_busy); | |
1271 | kcb = get_kprobe_ctlblk(); | |
1272 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
1273 | } | |
1274 | ||
1275 | void kprobe_busy_end(void) | |
1276 | { | |
1277 | __this_cpu_write(current_kprobe, NULL); | |
1278 | preempt_enable(); | |
1279 | } | |
1280 | ||
b94cce92 | 1281 | /* |
670721c7 | 1282 | * This function is called from delayed_put_task_struct() when a task is |
79ef0c00 LT |
1283 | * dead and cleaned up to recycle any kretprobe instances associated with |
1284 | * this task. These left over instances represent probed functions that | |
1285 | * have been called but will never return. | |
b94cce92 | 1286 | */ |
820aede0 | 1287 | void kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 1288 | { |
62c27be0 | 1289 | struct kretprobe_instance *ri; |
d741bf41 | 1290 | struct llist_node *node; |
802eae7c | 1291 | |
d741bf41 | 1292 | /* Early boot, not yet initialized. */ |
ef53d9c5 | 1293 | if (unlikely(!kprobes_initialized)) |
ef53d9c5 S |
1294 | return; |
1295 | ||
9b38cc70 JO |
1296 | kprobe_busy_begin(); |
1297 | ||
d741bf41 PZ |
1298 | node = __llist_del_all(&tk->kretprobe_instances); |
1299 | while (node) { | |
1300 | ri = container_of(node, struct kretprobe_instance, llist); | |
1301 | node = node->next; | |
1302 | ||
1303 | recycle_rp_inst(ri); | |
62c27be0 | 1304 | } |
9b38cc70 JO |
1305 | |
1306 | kprobe_busy_end(); | |
b94cce92 | 1307 | } |
820aede0 | 1308 | NOKPROBE_SYMBOL(kprobe_flush_task); |
b94cce92 | 1309 | |
b94cce92 HN |
1310 | static inline void free_rp_inst(struct kretprobe *rp) |
1311 | { | |
1312 | struct kretprobe_instance *ri; | |
6e426e0f | 1313 | struct freelist_node *node; |
d741bf41 | 1314 | int count = 0; |
4c4308cb | 1315 | |
6e426e0f PZ |
1316 | node = rp->freelist.head; |
1317 | while (node) { | |
1318 | ri = container_of(node, struct kretprobe_instance, freelist); | |
1319 | node = node->next; | |
1320 | ||
b94cce92 | 1321 | kfree(ri); |
d741bf41 | 1322 | count++; |
b94cce92 | 1323 | } |
ef53d9c5 | 1324 | |
d741bf41 PZ |
1325 | if (refcount_sub_and_test(count, &rp->rph->ref)) { |
1326 | kfree(rp->rph); | |
1327 | rp->rph = NULL; | |
4a296e07 | 1328 | } |
4a296e07 MH |
1329 | } |
1330 | ||
223a76b2 | 1331 | /* Add the new probe to 'ap->list'. */ |
55479f64 | 1332 | static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1333 | { |
059053a2 | 1334 | if (p->post_handler) |
6274de49 | 1335 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1336 | |
059053a2 | 1337 | list_add_rcu(&p->list, &ap->list); |
b918e5e6 MH |
1338 | if (p->post_handler && !ap->post_handler) |
1339 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1340 | |
8b0914ea PP |
1341 | return 0; |
1342 | } | |
1343 | ||
64f562c6 | 1344 | /* |
223a76b2 MH |
1345 | * Fill in the required fields of the aggregator kprobe. Replace the |
1346 | * earlier kprobe in the hlist with the aggregator kprobe. | |
64f562c6 | 1347 | */ |
55479f64 | 1348 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1349 | { |
223a76b2 | 1350 | /* Copy the insn slot of 'p' to 'ap'. */ |
8b0914ea | 1351 | copy_kprobe(p, ap); |
a9ad965e | 1352 | flush_insn_slot(ap); |
64f562c6 | 1353 | ap->addr = p->addr; |
afd66255 | 1354 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1355 | ap->pre_handler = aggr_pre_handler; |
e8386a0c MH |
1356 | /* We don't care the kprobe which has gone. */ |
1357 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1358 | ap->post_handler = aggr_post_handler; |
64f562c6 AM |
1359 | |
1360 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1361 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1362 | |
afd66255 | 1363 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1364 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1365 | } |
1366 | ||
1367 | /* | |
223a76b2 | 1368 | * This registers the second or subsequent kprobe at the same address. |
64f562c6 | 1369 | */ |
55479f64 | 1370 | static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
64f562c6 AM |
1371 | { |
1372 | int ret = 0; | |
6d8e40a8 | 1373 | struct kprobe *ap = orig_p; |
64f562c6 | 1374 | |
2d1e38f5 TG |
1375 | cpus_read_lock(); |
1376 | ||
25764288 MH |
1377 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1378 | jump_label_lock(); | |
25764288 MH |
1379 | mutex_lock(&text_mutex); |
1380 | ||
6d8e40a8 | 1381 | if (!kprobe_aggrprobe(orig_p)) { |
223a76b2 | 1382 | /* If 'orig_p' is not an 'aggr_kprobe', create new one. */ |
6d8e40a8 | 1383 | ap = alloc_aggr_kprobe(orig_p); |
25764288 MH |
1384 | if (!ap) { |
1385 | ret = -ENOMEM; | |
1386 | goto out; | |
1387 | } | |
6d8e40a8 | 1388 | init_aggr_kprobe(ap, orig_p); |
819319fc | 1389 | } else if (kprobe_unused(ap)) { |
0490cd1f | 1390 | /* This probe is going to die. Rescue it */ |
819319fc MH |
1391 | ret = reuse_unused_kprobe(ap); |
1392 | if (ret) | |
1393 | goto out; | |
1394 | } | |
b918e5e6 MH |
1395 | |
1396 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1397 | /* |
1398 | * Attempting to insert new probe at the same location that | |
1399 | * had a probe in the module vaddr area which already | |
1400 | * freed. So, the instruction slot has already been | |
1401 | * released. We need a new slot for the new probe. | |
1402 | */ | |
b918e5e6 | 1403 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1404 | if (ret) |
b918e5e6 MH |
1405 | /* |
1406 | * Even if fail to allocate new slot, don't need to | |
223a76b2 MH |
1407 | * free the 'ap'. It will be used next time, or |
1408 | * freed by unregister_kprobe(). | |
b918e5e6 | 1409 | */ |
25764288 | 1410 | goto out; |
de5bd88d | 1411 | |
afd66255 MH |
1412 | /* Prepare optimized instructions if possible. */ |
1413 | prepare_optimized_kprobe(ap); | |
1414 | ||
e8386a0c | 1415 | /* |
de5bd88d MH |
1416 | * Clear gone flag to prevent allocating new slot again, and |
1417 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1418 | */ |
de5bd88d MH |
1419 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1420 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1421 | } |
b918e5e6 | 1422 | |
223a76b2 | 1423 | /* Copy the insn slot of 'p' to 'ap'. */ |
b918e5e6 | 1424 | copy_kprobe(ap, p); |
25764288 MH |
1425 | ret = add_new_kprobe(ap, p); |
1426 | ||
1427 | out: | |
1428 | mutex_unlock(&text_mutex); | |
25764288 | 1429 | jump_label_unlock(); |
2d1e38f5 | 1430 | cpus_read_unlock(); |
25764288 MH |
1431 | |
1432 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1433 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
12310e34 | 1434 | if (!kprobes_all_disarmed) { |
25764288 | 1435 | /* Arm the breakpoint again. */ |
12310e34 JY |
1436 | ret = arm_kprobe(ap); |
1437 | if (ret) { | |
1438 | ap->flags |= KPROBE_FLAG_DISABLED; | |
1439 | list_del_rcu(&p->list); | |
ae8b7ce7 | 1440 | synchronize_rcu(); |
12310e34 JY |
1441 | } |
1442 | } | |
25764288 MH |
1443 | } |
1444 | return ret; | |
64f562c6 AM |
1445 | } |
1446 | ||
be8f2743 MH |
1447 | bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
1448 | { | |
223a76b2 | 1449 | /* The '__kprobes' functions and entry code must not be probed. */ |
be8f2743 MH |
1450 | return addr >= (unsigned long)__kprobes_text_start && |
1451 | addr < (unsigned long)__kprobes_text_end; | |
1452 | } | |
1453 | ||
6143c6fb | 1454 | static bool __within_kprobe_blacklist(unsigned long addr) |
d0aaff97 | 1455 | { |
376e2424 | 1456 | struct kprobe_blacklist_entry *ent; |
3d8d996e | 1457 | |
be8f2743 | 1458 | if (arch_within_kprobe_blacklist(addr)) |
376e2424 | 1459 | return true; |
3d8d996e | 1460 | /* |
223a76b2 MH |
1461 | * If 'kprobe_blacklist' is defined, check the address and |
1462 | * reject any probe registration in the prohibited area. | |
3d8d996e | 1463 | */ |
376e2424 MH |
1464 | list_for_each_entry(ent, &kprobe_blacklist, list) { |
1465 | if (addr >= ent->start_addr && addr < ent->end_addr) | |
1466 | return true; | |
3d8d996e | 1467 | } |
6143c6fb MH |
1468 | return false; |
1469 | } | |
376e2424 | 1470 | |
6143c6fb MH |
1471 | bool within_kprobe_blacklist(unsigned long addr) |
1472 | { | |
1473 | char symname[KSYM_NAME_LEN], *p; | |
1474 | ||
1475 | if (__within_kprobe_blacklist(addr)) | |
1476 | return true; | |
1477 | ||
1478 | /* Check if the address is on a suffixed-symbol */ | |
1479 | if (!lookup_symbol_name(addr, symname)) { | |
1480 | p = strchr(symname, '.'); | |
1481 | if (!p) | |
1482 | return false; | |
1483 | *p = '\0'; | |
1484 | addr = (unsigned long)kprobe_lookup_name(symname, 0); | |
1485 | if (addr) | |
1486 | return __within_kprobe_blacklist(addr); | |
1487 | } | |
376e2424 | 1488 | return false; |
d0aaff97 PP |
1489 | } |
1490 | ||
cc66bb91 PZ |
1491 | /* |
1492 | * arch_adjust_kprobe_addr - adjust the address | |
1493 | * @addr: symbol base address | |
1494 | * @offset: offset within the symbol | |
1495 | * @on_func_entry: was this @addr+@offset on the function entry | |
1496 | * | |
1497 | * Typically returns @addr + @offset, except for special cases where the | |
1498 | * function might be prefixed by a CFI landing pad, in that case any offset | |
1499 | * inside the landing pad is mapped to the first 'real' instruction of the | |
1500 | * symbol. | |
1501 | * | |
1502 | * Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C | |
1503 | * instruction at +0. | |
1504 | */ | |
1505 | kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr, | |
1506 | unsigned long offset, | |
1507 | bool *on_func_entry) | |
1508 | { | |
1509 | *on_func_entry = !offset; | |
1510 | return (kprobe_opcode_t *)(addr + offset); | |
1511 | } | |
1512 | ||
b2a5cd69 | 1513 | /* |
223a76b2 | 1514 | * If 'symbol_name' is specified, look it up and add the 'offset' |
b2a5cd69 | 1515 | * to it. This way, we can specify a relative address to a symbol. |
bc81d48d MH |
1516 | * This returns encoded errors if it fails to look up symbol or invalid |
1517 | * combination of parameters. | |
b2a5cd69 | 1518 | */ |
cc66bb91 PZ |
1519 | static kprobe_opcode_t * |
1520 | _kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name, | |
1521 | unsigned long offset, bool *on_func_entry) | |
b2a5cd69 | 1522 | { |
1d585e70 | 1523 | if ((symbol_name && addr) || (!symbol_name && !addr)) |
bc81d48d MH |
1524 | goto invalid; |
1525 | ||
1d585e70 | 1526 | if (symbol_name) { |
cc66bb91 PZ |
1527 | /* |
1528 | * Input: @sym + @offset | |
1529 | * Output: @addr + @offset | |
1530 | * | |
1531 | * NOTE: kprobe_lookup_name() does *NOT* fold the offset | |
1532 | * argument into it's output! | |
1533 | */ | |
7246f600 | 1534 | addr = kprobe_lookup_name(symbol_name, offset); |
bc81d48d MH |
1535 | if (!addr) |
1536 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1537 | } |
1538 | ||
cc66bb91 PZ |
1539 | /* |
1540 | * So here we have @addr + @offset, displace it into a new | |
1541 | * @addr' + @offset' where @addr' is the symbol start address. | |
1542 | */ | |
1543 | addr = (void *)addr + offset; | |
1544 | if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset)) | |
1545 | return ERR_PTR(-ENOENT); | |
1546 | addr = (void *)addr - offset; | |
1547 | ||
1548 | /* | |
1549 | * Then ask the architecture to re-combine them, taking care of | |
1550 | * magical function entry details while telling us if this was indeed | |
1551 | * at the start of the function. | |
1552 | */ | |
1553 | addr = arch_adjust_kprobe_addr((unsigned long)addr, offset, on_func_entry); | |
bc81d48d MH |
1554 | if (addr) |
1555 | return addr; | |
1556 | ||
1557 | invalid: | |
1558 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1559 | } |
1560 | ||
1d585e70 NR |
1561 | static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
1562 | { | |
cc66bb91 PZ |
1563 | bool on_func_entry; |
1564 | return _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry); | |
1d585e70 NR |
1565 | } |
1566 | ||
223a76b2 MH |
1567 | /* |
1568 | * Check the 'p' is valid and return the aggregator kprobe | |
1569 | * at the same address. | |
1570 | */ | |
55479f64 | 1571 | static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
1f0ab409 | 1572 | { |
6d8e40a8 | 1573 | struct kprobe *ap, *list_p; |
1f0ab409 | 1574 | |
7e6a71d8 MH |
1575 | lockdep_assert_held(&kprobe_mutex); |
1576 | ||
6d8e40a8 MH |
1577 | ap = get_kprobe(p->addr); |
1578 | if (unlikely(!ap)) | |
1f0ab409 AM |
1579 | return NULL; |
1580 | ||
6d8e40a8 | 1581 | if (p != ap) { |
7e6a71d8 | 1582 | list_for_each_entry(list_p, &ap->list, list) |
1f0ab409 AM |
1583 | if (list_p == p) |
1584 | /* kprobe p is a valid probe */ | |
1585 | goto valid; | |
1586 | return NULL; | |
1587 | } | |
1588 | valid: | |
6d8e40a8 | 1589 | return ap; |
1f0ab409 AM |
1590 | } |
1591 | ||
33b1d146 MH |
1592 | /* |
1593 | * Warn and return error if the kprobe is being re-registered since | |
1594 | * there must be a software bug. | |
1595 | */ | |
1596 | static inline int warn_kprobe_rereg(struct kprobe *p) | |
1f0ab409 AM |
1597 | { |
1598 | int ret = 0; | |
1f0ab409 AM |
1599 | |
1600 | mutex_lock(&kprobe_mutex); | |
33b1d146 | 1601 | if (WARN_ON_ONCE(__get_valid_kprobe(p))) |
1f0ab409 AM |
1602 | ret = -EINVAL; |
1603 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1604 | |
1f0ab409 AM |
1605 | return ret; |
1606 | } | |
1607 | ||
4402deae | 1608 | static int check_ftrace_location(struct kprobe *p) |
1da177e4 | 1609 | { |
aebfd125 | 1610 | unsigned long addr = (unsigned long)p->addr; |
ae6aa16f | 1611 | |
aebfd125 | 1612 | if (ftrace_location(addr) == addr) { |
e7dbfe34 | 1613 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 1614 | p->flags |= KPROBE_FLAG_FTRACE; |
e7dbfe34 | 1615 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
1616 | return -EINVAL; |
1617 | #endif | |
1618 | } | |
f7f242ff HC |
1619 | return 0; |
1620 | } | |
1621 | ||
1622 | static int check_kprobe_address_safe(struct kprobe *p, | |
1623 | struct module **probed_mod) | |
1624 | { | |
1625 | int ret; | |
1f0ab409 | 1626 | |
4402deae | 1627 | ret = check_ftrace_location(p); |
f7f242ff HC |
1628 | if (ret) |
1629 | return ret; | |
91bad2f8 | 1630 | jump_label_lock(); |
de31c3ca | 1631 | preempt_disable(); |
f7fa6ef0 MH |
1632 | |
1633 | /* Ensure it is not in reserved area nor out of text */ | |
ec30c5f3 | 1634 | if (!kernel_text_address((unsigned long) p->addr) || |
376e2424 | 1635 | within_kprobe_blacklist((unsigned long) p->addr) || |
e336b402 | 1636 | jump_label_text_reserved(p->addr, p->addr) || |
fa68bd09 | 1637 | static_call_text_reserved(p->addr, p->addr) || |
e336b402 | 1638 | find_bug((unsigned long)p->addr)) { |
f986a499 | 1639 | ret = -EINVAL; |
f7fa6ef0 | 1640 | goto out; |
f986a499 | 1641 | } |
b3e55c72 | 1642 | |
223a76b2 | 1643 | /* Check if 'p' is probing a module. */ |
f7fa6ef0 MH |
1644 | *probed_mod = __module_text_address((unsigned long) p->addr); |
1645 | if (*probed_mod) { | |
6f716acd | 1646 | /* |
e8386a0c MH |
1647 | * We must hold a refcount of the probed module while updating |
1648 | * its code to prohibit unexpected unloading. | |
df019b1d | 1649 | */ |
f7fa6ef0 MH |
1650 | if (unlikely(!try_module_get(*probed_mod))) { |
1651 | ret = -ENOENT; | |
1652 | goto out; | |
1653 | } | |
de31c3ca | 1654 | |
f24659d9 | 1655 | /* |
223a76b2 | 1656 | * If the module freed '.init.text', we couldn't insert |
f24659d9 MH |
1657 | * kprobes in there. |
1658 | */ | |
f7fa6ef0 MH |
1659 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
1660 | (*probed_mod)->state != MODULE_STATE_COMING) { | |
1661 | module_put(*probed_mod); | |
1662 | *probed_mod = NULL; | |
1663 | ret = -ENOENT; | |
f24659d9 | 1664 | } |
df019b1d | 1665 | } |
f7fa6ef0 | 1666 | out: |
a189d035 | 1667 | preempt_enable(); |
de31c3ca | 1668 | jump_label_unlock(); |
1da177e4 | 1669 | |
f7fa6ef0 MH |
1670 | return ret; |
1671 | } | |
1672 | ||
55479f64 | 1673 | int register_kprobe(struct kprobe *p) |
f7fa6ef0 MH |
1674 | { |
1675 | int ret; | |
1676 | struct kprobe *old_p; | |
1677 | struct module *probed_mod; | |
1678 | kprobe_opcode_t *addr; | |
1679 | ||
1680 | /* Adjust probe address from symbol */ | |
1681 | addr = kprobe_addr(p); | |
1682 | if (IS_ERR(addr)) | |
1683 | return PTR_ERR(addr); | |
1684 | p->addr = addr; | |
1685 | ||
33b1d146 | 1686 | ret = warn_kprobe_rereg(p); |
f7fa6ef0 MH |
1687 | if (ret) |
1688 | return ret; | |
1689 | ||
1690 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ | |
1691 | p->flags &= KPROBE_FLAG_DISABLED; | |
3516a460 | 1692 | p->nmissed = 0; |
9861668f | 1693 | INIT_LIST_HEAD(&p->list); |
afd66255 | 1694 | |
f7fa6ef0 MH |
1695 | ret = check_kprobe_address_safe(p, &probed_mod); |
1696 | if (ret) | |
1697 | return ret; | |
1698 | ||
1699 | mutex_lock(&kprobe_mutex); | |
afd66255 | 1700 | |
64f562c6 AM |
1701 | old_p = get_kprobe(p->addr); |
1702 | if (old_p) { | |
223a76b2 | 1703 | /* Since this may unoptimize 'old_p', locking 'text_mutex'. */ |
64f562c6 | 1704 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1705 | goto out; |
1706 | } | |
1da177e4 | 1707 | |
2d1e38f5 TG |
1708 | cpus_read_lock(); |
1709 | /* Prevent text modification */ | |
1710 | mutex_lock(&text_mutex); | |
ae6aa16f | 1711 | ret = prepare_kprobe(p); |
25764288 | 1712 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1713 | cpus_read_unlock(); |
6f716acd | 1714 | if (ret) |
afd66255 | 1715 | goto out; |
49a2a1b8 | 1716 | |
64f562c6 | 1717 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1718 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1719 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1720 | ||
12310e34 JY |
1721 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) { |
1722 | ret = arm_kprobe(p); | |
1723 | if (ret) { | |
1724 | hlist_del_rcu(&p->hlist); | |
ae8b7ce7 | 1725 | synchronize_rcu(); |
12310e34 JY |
1726 | goto out; |
1727 | } | |
1728 | } | |
afd66255 MH |
1729 | |
1730 | /* Try to optimize kprobe */ | |
1731 | try_to_optimize_kprobe(p); | |
1da177e4 | 1732 | out: |
7a7d1cf9 | 1733 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1734 | |
e8386a0c | 1735 | if (probed_mod) |
df019b1d | 1736 | module_put(probed_mod); |
e8386a0c | 1737 | |
1da177e4 LT |
1738 | return ret; |
1739 | } | |
99081ab5 | 1740 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1741 | |
223a76b2 | 1742 | /* Check if all probes on the 'ap' are disabled. */ |
29e8077a | 1743 | static bool aggr_kprobe_disabled(struct kprobe *ap) |
6f0f1dd7 MH |
1744 | { |
1745 | struct kprobe *kp; | |
1746 | ||
7e6a71d8 MH |
1747 | lockdep_assert_held(&kprobe_mutex); |
1748 | ||
1749 | list_for_each_entry(kp, &ap->list, list) | |
6f0f1dd7 MH |
1750 | if (!kprobe_disabled(kp)) |
1751 | /* | |
223a76b2 MH |
1752 | * Since there is an active probe on the list, |
1753 | * we can't disable this 'ap'. | |
6f0f1dd7 | 1754 | */ |
29e8077a | 1755 | return false; |
6f0f1dd7 | 1756 | |
29e8077a | 1757 | return true; |
6f0f1dd7 MH |
1758 | } |
1759 | ||
55479f64 | 1760 | static struct kprobe *__disable_kprobe(struct kprobe *p) |
6f0f1dd7 MH |
1761 | { |
1762 | struct kprobe *orig_p; | |
297f9233 | 1763 | int ret; |
6f0f1dd7 | 1764 | |
57d4e317 MH |
1765 | lockdep_assert_held(&kprobe_mutex); |
1766 | ||
6f0f1dd7 MH |
1767 | /* Get an original kprobe for return */ |
1768 | orig_p = __get_valid_kprobe(p); | |
1769 | if (unlikely(orig_p == NULL)) | |
297f9233 | 1770 | return ERR_PTR(-EINVAL); |
6f0f1dd7 MH |
1771 | |
1772 | if (!kprobe_disabled(p)) { | |
1773 | /* Disable probe if it is a child probe */ | |
1774 | if (p != orig_p) | |
1775 | p->flags |= KPROBE_FLAG_DISABLED; | |
1776 | ||
1777 | /* Try to disarm and disable this/parent probe */ | |
1778 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
69d54b91 | 1779 | /* |
223a76b2 | 1780 | * If 'kprobes_all_disarmed' is set, 'orig_p' |
69d54b91 WN |
1781 | * should have already been disarmed, so |
1782 | * skip unneed disarming process. | |
1783 | */ | |
297f9233 JY |
1784 | if (!kprobes_all_disarmed) { |
1785 | ret = disarm_kprobe(orig_p, true); | |
1786 | if (ret) { | |
1787 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1788 | return ERR_PTR(ret); | |
1789 | } | |
1790 | } | |
6f0f1dd7 MH |
1791 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1792 | } | |
1793 | } | |
1794 | ||
1795 | return orig_p; | |
1796 | } | |
1797 | ||
de5bd88d MH |
1798 | /* |
1799 | * Unregister a kprobe without a scheduler synchronization. | |
1800 | */ | |
55479f64 | 1801 | static int __unregister_kprobe_top(struct kprobe *p) |
de5bd88d | 1802 | { |
6d8e40a8 | 1803 | struct kprobe *ap, *list_p; |
de5bd88d | 1804 | |
6f0f1dd7 MH |
1805 | /* Disable kprobe. This will disarm it if needed. */ |
1806 | ap = __disable_kprobe(p); | |
297f9233 JY |
1807 | if (IS_ERR(ap)) |
1808 | return PTR_ERR(ap); | |
de5bd88d | 1809 | |
6f0f1dd7 | 1810 | if (ap == p) |
bf8f6e5b | 1811 | /* |
6f0f1dd7 MH |
1812 | * This probe is an independent(and non-optimized) kprobe |
1813 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1814 | */ |
6f0f1dd7 MH |
1815 | goto disarmed; |
1816 | ||
1817 | /* Following process expects this probe is an aggrprobe */ | |
1818 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1819 | ||
6274de49 MH |
1820 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1821 | /* | |
1822 | * !disarmed could be happen if the probe is under delayed | |
1823 | * unoptimizing. | |
1824 | */ | |
6f0f1dd7 MH |
1825 | goto disarmed; |
1826 | else { | |
1827 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1828 | if (p->post_handler && !kprobe_gone(p)) { |
7e6a71d8 | 1829 | list_for_each_entry(list_p, &ap->list, list) { |
9861668f MH |
1830 | if ((list_p != p) && (list_p->post_handler)) |
1831 | goto noclean; | |
1832 | } | |
6d8e40a8 | 1833 | ap->post_handler = NULL; |
9861668f MH |
1834 | } |
1835 | noclean: | |
6f0f1dd7 MH |
1836 | /* |
1837 | * Remove from the aggrprobe: this path will do nothing in | |
1838 | * __unregister_kprobe_bottom(). | |
1839 | */ | |
49a2a1b8 | 1840 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1841 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1842 | /* | |
1843 | * Try to optimize this probe again, because post | |
1844 | * handler may have been changed. | |
1845 | */ | |
1846 | optimize_kprobe(ap); | |
49a2a1b8 | 1847 | } |
9861668f | 1848 | return 0; |
6f0f1dd7 MH |
1849 | |
1850 | disarmed: | |
1851 | hlist_del_rcu(&ap->hlist); | |
1852 | return 0; | |
9861668f | 1853 | } |
3516a460 | 1854 | |
55479f64 | 1855 | static void __unregister_kprobe_bottom(struct kprobe *p) |
9861668f | 1856 | { |
6d8e40a8 | 1857 | struct kprobe *ap; |
b3e55c72 | 1858 | |
e8386a0c | 1859 | if (list_empty(&p->list)) |
6274de49 | 1860 | /* This is an independent kprobe */ |
0498b635 | 1861 | arch_remove_kprobe(p); |
e8386a0c | 1862 | else if (list_is_singular(&p->list)) { |
6274de49 | 1863 | /* This is the last child of an aggrprobe */ |
6d8e40a8 | 1864 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1865 | list_del(&p->list); |
6d8e40a8 | 1866 | free_aggr_kprobe(ap); |
9861668f | 1867 | } |
6274de49 | 1868 | /* Otherwise, do nothing. */ |
9861668f MH |
1869 | } |
1870 | ||
55479f64 | 1871 | int register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1872 | { |
1873 | int i, ret = 0; | |
1874 | ||
1875 | if (num <= 0) | |
1876 | return -EINVAL; | |
1877 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1878 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1879 | if (ret < 0) { |
1880 | if (i > 0) | |
1881 | unregister_kprobes(kps, i); | |
9861668f | 1882 | break; |
36721656 | 1883 | } |
49a2a1b8 | 1884 | } |
9861668f MH |
1885 | return ret; |
1886 | } | |
99081ab5 | 1887 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1888 | |
55479f64 | 1889 | void unregister_kprobe(struct kprobe *p) |
9861668f MH |
1890 | { |
1891 | unregister_kprobes(&p, 1); | |
1892 | } | |
99081ab5 | 1893 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1894 | |
55479f64 | 1895 | void unregister_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1896 | { |
1897 | int i; | |
1898 | ||
1899 | if (num <= 0) | |
1900 | return; | |
1901 | mutex_lock(&kprobe_mutex); | |
1902 | for (i = 0; i < num; i++) | |
1903 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1904 | kps[i]->addr = NULL; | |
1905 | mutex_unlock(&kprobe_mutex); | |
1906 | ||
ae8b7ce7 | 1907 | synchronize_rcu(); |
9861668f MH |
1908 | for (i = 0; i < num; i++) |
1909 | if (kps[i]->addr) | |
1910 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1911 | } |
99081ab5 | 1912 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 | 1913 | |
5f6bee34 NR |
1914 | int __weak kprobe_exceptions_notify(struct notifier_block *self, |
1915 | unsigned long val, void *data) | |
fc62d020 NR |
1916 | { |
1917 | return NOTIFY_DONE; | |
1918 | } | |
5f6bee34 | 1919 | NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
fc62d020 | 1920 | |
1da177e4 | 1921 | static struct notifier_block kprobe_exceptions_nb = { |
3d5631e0 AK |
1922 | .notifier_call = kprobe_exceptions_notify, |
1923 | .priority = 0x7fffffff /* we need to be notified first */ | |
1924 | }; | |
1925 | ||
9edddaa2 | 1926 | #ifdef CONFIG_KRETPROBES |
66ada2cc | 1927 | |
03bac0df MH |
1928 | /* This assumes the 'tsk' is the current task or the is not running. */ |
1929 | static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk, | |
1930 | struct llist_node **cur) | |
3d7e3382 | 1931 | { |
d741bf41 | 1932 | struct kretprobe_instance *ri = NULL; |
03bac0df MH |
1933 | struct llist_node *node = *cur; |
1934 | ||
1935 | if (!node) | |
1936 | node = tsk->kretprobe_instances.first; | |
1937 | else | |
1938 | node = node->next; | |
66ada2cc | 1939 | |
d741bf41 PZ |
1940 | while (node) { |
1941 | ri = container_of(node, struct kretprobe_instance, llist); | |
96fed8ac | 1942 | if (ri->ret_addr != kretprobe_trampoline_addr()) { |
03bac0df MH |
1943 | *cur = node; |
1944 | return ri->ret_addr; | |
d741bf41 | 1945 | } |
d741bf41 | 1946 | node = node->next; |
66ada2cc | 1947 | } |
03bac0df | 1948 | return NULL; |
3d7e3382 | 1949 | } |
03bac0df | 1950 | NOKPROBE_SYMBOL(__kretprobe_find_ret_addr); |
1da177e4 | 1951 | |
03bac0df MH |
1952 | /** |
1953 | * kretprobe_find_ret_addr -- Find correct return address modified by kretprobe | |
1954 | * @tsk: Target task | |
1955 | * @fp: A frame pointer | |
1956 | * @cur: a storage of the loop cursor llist_node pointer for next call | |
1957 | * | |
1958 | * Find the correct return address modified by a kretprobe on @tsk in unsigned | |
1959 | * long type. If it finds the return address, this returns that address value, | |
1960 | * or this returns 0. | |
1961 | * The @tsk must be 'current' or a task which is not running. @fp is a hint | |
1962 | * to get the currect return address - which is compared with the | |
1963 | * kretprobe_instance::fp field. The @cur is a loop cursor for searching the | |
1964 | * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the | |
1965 | * first call, but '@cur' itself must NOT NULL. | |
1966 | */ | |
1967 | unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, | |
1968 | struct llist_node **cur) | |
1969 | { | |
1970 | struct kretprobe_instance *ri = NULL; | |
1971 | kprobe_opcode_t *ret; | |
1972 | ||
1973 | if (WARN_ON_ONCE(!cur)) | |
1974 | return 0; | |
66ada2cc | 1975 | |
03bac0df MH |
1976 | do { |
1977 | ret = __kretprobe_find_ret_addr(tsk, cur); | |
1978 | if (!ret) | |
1979 | break; | |
1980 | ri = container_of(*cur, struct kretprobe_instance, llist); | |
1981 | } while (ri->fp != fp); | |
1982 | ||
1983 | return (unsigned long)ret; | |
1984 | } | |
1985 | NOKPROBE_SYMBOL(kretprobe_find_ret_addr); | |
1986 | ||
bf094cff MH |
1987 | void __weak arch_kretprobe_fixup_return(struct pt_regs *regs, |
1988 | kprobe_opcode_t *correct_ret_addr) | |
1989 | { | |
1990 | /* | |
1991 | * Do nothing by default. Please fill this to update the fake return | |
1992 | * address on the stack with the correct one on each arch if possible. | |
1993 | */ | |
1994 | } | |
66ada2cc MH |
1995 | |
1996 | unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, | |
66ada2cc MH |
1997 | void *frame_pointer) |
1998 | { | |
66ada2cc | 1999 | kprobe_opcode_t *correct_ret_addr = NULL; |
d741bf41 | 2000 | struct kretprobe_instance *ri = NULL; |
03bac0df | 2001 | struct llist_node *first, *node = NULL; |
d741bf41 | 2002 | struct kretprobe *rp; |
66ada2cc | 2003 | |
03bac0df MH |
2004 | /* Find correct address and all nodes for this frame. */ |
2005 | correct_ret_addr = __kretprobe_find_ret_addr(current, &node); | |
2006 | if (!correct_ret_addr) { | |
2007 | pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n"); | |
2008 | BUG_ON(1); | |
66ada2cc MH |
2009 | } |
2010 | ||
df91c5bc MH |
2011 | /* |
2012 | * Set the return address as the instruction pointer, because if the | |
2013 | * user handler calls stack_trace_save_regs() with this 'regs', | |
2014 | * the stack trace will start from the instruction pointer. | |
2015 | */ | |
2016 | instruction_pointer_set(regs, (unsigned long)correct_ret_addr); | |
66ada2cc | 2017 | |
03bac0df MH |
2018 | /* Run the user handler of the nodes. */ |
2019 | first = current->kretprobe_instances.first; | |
d741bf41 PZ |
2020 | while (first) { |
2021 | ri = container_of(first, struct kretprobe_instance, llist); | |
03bac0df MH |
2022 | |
2023 | if (WARN_ON_ONCE(ri->fp != frame_pointer)) | |
2024 | break; | |
66ada2cc | 2025 | |
d741bf41 PZ |
2026 | rp = get_kretprobe(ri); |
2027 | if (rp && rp->handler) { | |
66ada2cc MH |
2028 | struct kprobe *prev = kprobe_running(); |
2029 | ||
d741bf41 | 2030 | __this_cpu_write(current_kprobe, &rp->kp); |
66ada2cc | 2031 | ri->ret_addr = correct_ret_addr; |
d741bf41 | 2032 | rp->handler(ri, regs); |
66ada2cc MH |
2033 | __this_cpu_write(current_kprobe, prev); |
2034 | } | |
03bac0df MH |
2035 | if (first == node) |
2036 | break; | |
2037 | ||
2038 | first = first->next; | |
2039 | } | |
2040 | ||
bf094cff MH |
2041 | arch_kretprobe_fixup_return(regs, correct_ret_addr); |
2042 | ||
03bac0df MH |
2043 | /* Unlink all nodes for this frame. */ |
2044 | first = current->kretprobe_instances.first; | |
2045 | current->kretprobe_instances.first = node->next; | |
2046 | node->next = NULL; | |
2047 | ||
2048 | /* Recycle free instances. */ | |
2049 | while (first) { | |
2050 | ri = container_of(first, struct kretprobe_instance, llist); | |
2051 | first = first->next; | |
66ada2cc | 2052 | |
b3388178 | 2053 | recycle_rp_inst(ri); |
66ada2cc MH |
2054 | } |
2055 | ||
66ada2cc MH |
2056 | return (unsigned long)correct_ret_addr; |
2057 | } | |
2058 | NOKPROBE_SYMBOL(__kretprobe_trampoline_handler) | |
2059 | ||
e65cefe8 AB |
2060 | /* |
2061 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
2062 | * hits it will set up the return probe. | |
2063 | */ | |
820aede0 | 2064 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
e65cefe8 AB |
2065 | { |
2066 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 | 2067 | struct kretprobe_instance *ri; |
6e426e0f | 2068 | struct freelist_node *fn; |
e65cefe8 | 2069 | |
6e426e0f PZ |
2070 | fn = freelist_try_get(&rp->freelist); |
2071 | if (!fn) { | |
2072 | rp->nmissed++; | |
2073 | return 0; | |
2074 | } | |
4c4308cb | 2075 | |
6e426e0f | 2076 | ri = container_of(fn, struct kretprobe_instance, freelist); |
d741bf41 | 2077 | |
6e426e0f PZ |
2078 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
2079 | freelist_add(&ri->freelist, &rp->freelist); | |
2080 | return 0; | |
ef53d9c5 | 2081 | } |
6e426e0f PZ |
2082 | |
2083 | arch_prepare_kretprobe(ri, regs); | |
2084 | ||
2085 | __llist_add(&ri->llist, ¤t->kretprobe_instances); | |
2086 | ||
e65cefe8 AB |
2087 | return 0; |
2088 | } | |
820aede0 | 2089 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
e65cefe8 | 2090 | |
97c753e6 MH |
2091 | /** |
2092 | * kprobe_on_func_entry() -- check whether given address is function entry | |
2093 | * @addr: Target address | |
2094 | * @sym: Target symbol name | |
2095 | * @offset: The offset from the symbol or the address | |
2096 | * | |
2097 | * This checks whether the given @addr+@offset or @sym+@offset is on the | |
2098 | * function entry address or not. | |
2099 | * This returns 0 if it is the function entry, or -EINVAL if it is not. | |
2100 | * And also it returns -ENOENT if it fails the symbol or address lookup. | |
2101 | * Caller must pass @addr or @sym (either one must be NULL), or this | |
2102 | * returns -EINVAL. | |
2103 | */ | |
2104 | int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) | |
1d585e70 | 2105 | { |
cc66bb91 PZ |
2106 | bool on_func_entry; |
2107 | kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset, &on_func_entry); | |
1d585e70 NR |
2108 | |
2109 | if (IS_ERR(kp_addr)) | |
97c753e6 | 2110 | return PTR_ERR(kp_addr); |
1d585e70 | 2111 | |
cc66bb91 | 2112 | if (!on_func_entry) |
97c753e6 MH |
2113 | return -EINVAL; |
2114 | ||
2115 | return 0; | |
1d585e70 NR |
2116 | } |
2117 | ||
55479f64 | 2118 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 | 2119 | { |
97c753e6 | 2120 | int ret; |
b94cce92 HN |
2121 | struct kretprobe_instance *inst; |
2122 | int i; | |
b2a5cd69 | 2123 | void *addr; |
90ec5e89 | 2124 | |
97c753e6 MH |
2125 | ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset); |
2126 | if (ret) | |
2127 | return ret; | |
f438d914 | 2128 | |
223a76b2 | 2129 | /* If only 'rp->kp.addr' is specified, check reregistering kprobes */ |
33b1d146 | 2130 | if (rp->kp.addr && warn_kprobe_rereg(&rp->kp)) |
0188b878 WS |
2131 | return -EINVAL; |
2132 | ||
f438d914 | 2133 | if (kretprobe_blacklist_size) { |
b2a5cd69 | 2134 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
2135 | if (IS_ERR(addr)) |
2136 | return PTR_ERR(addr); | |
f438d914 MH |
2137 | |
2138 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
2139 | if (kretprobe_blacklist[i].addr == addr) | |
2140 | return -EINVAL; | |
2141 | } | |
2142 | } | |
b94cce92 | 2143 | |
6bbfa441 MH |
2144 | if (rp->data_size > KRETPROBE_MAX_DATA_SIZE) |
2145 | return -E2BIG; | |
2146 | ||
b94cce92 | 2147 | rp->kp.pre_handler = pre_handler_kretprobe; |
7522a842 | 2148 | rp->kp.post_handler = NULL; |
b94cce92 HN |
2149 | |
2150 | /* Pre-allocate memory for max kretprobe instances */ | |
2151 | if (rp->maxactive <= 0) { | |
92616606 | 2152 | #ifdef CONFIG_PREEMPTION |
c2ef6661 | 2153 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 2154 | #else |
4dae560f | 2155 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
2156 | #endif |
2157 | } | |
6e426e0f | 2158 | rp->freelist.head = NULL; |
d741bf41 PZ |
2159 | rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL); |
2160 | if (!rp->rph) | |
2161 | return -ENOMEM; | |
2162 | ||
2163 | rp->rph->rp = rp; | |
b94cce92 | 2164 | for (i = 0; i < rp->maxactive; i++) { |
d741bf41 | 2165 | inst = kzalloc(sizeof(struct kretprobe_instance) + |
f47cd9b5 | 2166 | rp->data_size, GFP_KERNEL); |
b94cce92 | 2167 | if (inst == NULL) { |
d741bf41 | 2168 | refcount_set(&rp->rph->ref, i); |
b94cce92 HN |
2169 | free_rp_inst(rp); |
2170 | return -ENOMEM; | |
2171 | } | |
d741bf41 | 2172 | inst->rph = rp->rph; |
6e426e0f | 2173 | freelist_add(&inst->freelist, &rp->freelist); |
b94cce92 | 2174 | } |
d741bf41 | 2175 | refcount_set(&rp->rph->ref, i); |
b94cce92 HN |
2176 | |
2177 | rp->nmissed = 0; | |
2178 | /* Establish function entry probe point */ | |
49ad2fd7 | 2179 | ret = register_kprobe(&rp->kp); |
4a296e07 | 2180 | if (ret != 0) |
b94cce92 HN |
2181 | free_rp_inst(rp); |
2182 | return ret; | |
2183 | } | |
99081ab5 | 2184 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2185 | |
55479f64 | 2186 | int register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2187 | { |
2188 | int ret = 0, i; | |
2189 | ||
2190 | if (num <= 0) | |
2191 | return -EINVAL; | |
2192 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 2193 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
2194 | if (ret < 0) { |
2195 | if (i > 0) | |
2196 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
2197 | break; |
2198 | } | |
2199 | } | |
2200 | return ret; | |
2201 | } | |
99081ab5 | 2202 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 2203 | |
55479f64 | 2204 | void unregister_kretprobe(struct kretprobe *rp) |
4a296e07 MH |
2205 | { |
2206 | unregister_kretprobes(&rp, 1); | |
2207 | } | |
99081ab5 | 2208 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 2209 | |
55479f64 | 2210 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2211 | { |
2212 | int i; | |
2213 | ||
2214 | if (num <= 0) | |
2215 | return; | |
2216 | mutex_lock(&kprobe_mutex); | |
d741bf41 | 2217 | for (i = 0; i < num; i++) { |
4a296e07 MH |
2218 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
2219 | rps[i]->kp.addr = NULL; | |
d741bf41 PZ |
2220 | rps[i]->rph->rp = NULL; |
2221 | } | |
4a296e07 MH |
2222 | mutex_unlock(&kprobe_mutex); |
2223 | ||
ae8b7ce7 | 2224 | synchronize_rcu(); |
4a296e07 MH |
2225 | for (i = 0; i < num; i++) { |
2226 | if (rps[i]->kp.addr) { | |
2227 | __unregister_kprobe_bottom(&rps[i]->kp); | |
d741bf41 | 2228 | free_rp_inst(rps[i]); |
4a296e07 MH |
2229 | } |
2230 | } | |
2231 | } | |
99081ab5 | 2232 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 2233 | |
9edddaa2 | 2234 | #else /* CONFIG_KRETPROBES */ |
55479f64 | 2235 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 | 2236 | { |
223a76b2 | 2237 | return -EOPNOTSUPP; |
b94cce92 | 2238 | } |
99081ab5 | 2239 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2240 | |
55479f64 | 2241 | int register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 2242 | { |
223a76b2 | 2243 | return -EOPNOTSUPP; |
346fd59b | 2244 | } |
99081ab5 MH |
2245 | EXPORT_SYMBOL_GPL(register_kretprobes); |
2246 | ||
55479f64 | 2247 | void unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 2248 | { |
4a296e07 | 2249 | } |
99081ab5 | 2250 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 2251 | |
55479f64 | 2252 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2253 | { |
2254 | } | |
99081ab5 | 2255 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 2256 | |
820aede0 | 2257 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
4a296e07 MH |
2258 | { |
2259 | return 0; | |
b94cce92 | 2260 | } |
820aede0 | 2261 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
b94cce92 | 2262 | |
4a296e07 MH |
2263 | #endif /* CONFIG_KRETPROBES */ |
2264 | ||
e8386a0c | 2265 | /* Set the kprobe gone and remove its instruction buffer. */ |
55479f64 | 2266 | static void kill_kprobe(struct kprobe *p) |
e8386a0c MH |
2267 | { |
2268 | struct kprobe *kp; | |
de5bd88d | 2269 | |
7e6a71d8 MH |
2270 | lockdep_assert_held(&kprobe_mutex); |
2271 | ||
e8386a0c | 2272 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 2273 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
2274 | /* |
2275 | * If this is an aggr_kprobe, we have to list all the | |
2276 | * chained probes and mark them GONE. | |
2277 | */ | |
7e6a71d8 | 2278 | list_for_each_entry(kp, &p->list, list) |
e8386a0c MH |
2279 | kp->flags |= KPROBE_FLAG_GONE; |
2280 | p->post_handler = NULL; | |
afd66255 | 2281 | kill_optimized_kprobe(p); |
e8386a0c MH |
2282 | } |
2283 | /* | |
2284 | * Here, we can remove insn_slot safely, because no thread calls | |
2285 | * the original probed function (which will be freed soon) any more. | |
2286 | */ | |
2287 | arch_remove_kprobe(p); | |
0cb2f137 MS |
2288 | |
2289 | /* | |
2290 | * The module is going away. We should disarm the kprobe which | |
bcb53209 | 2291 | * is using ftrace, because ftrace framework is still available at |
223a76b2 | 2292 | * 'MODULE_STATE_GOING' notification. |
0cb2f137 | 2293 | */ |
bcb53209 | 2294 | if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed) |
0cb2f137 | 2295 | disarm_kprobe_ftrace(p); |
e8386a0c MH |
2296 | } |
2297 | ||
c0614829 | 2298 | /* Disable one kprobe */ |
55479f64 | 2299 | int disable_kprobe(struct kprobe *kp) |
c0614829 MH |
2300 | { |
2301 | int ret = 0; | |
297f9233 | 2302 | struct kprobe *p; |
c0614829 MH |
2303 | |
2304 | mutex_lock(&kprobe_mutex); | |
2305 | ||
6f0f1dd7 | 2306 | /* Disable this kprobe */ |
297f9233 JY |
2307 | p = __disable_kprobe(kp); |
2308 | if (IS_ERR(p)) | |
2309 | ret = PTR_ERR(p); | |
c0614829 | 2310 | |
c0614829 MH |
2311 | mutex_unlock(&kprobe_mutex); |
2312 | return ret; | |
2313 | } | |
2314 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
2315 | ||
2316 | /* Enable one kprobe */ | |
55479f64 | 2317 | int enable_kprobe(struct kprobe *kp) |
c0614829 MH |
2318 | { |
2319 | int ret = 0; | |
2320 | struct kprobe *p; | |
2321 | ||
2322 | mutex_lock(&kprobe_mutex); | |
2323 | ||
2324 | /* Check whether specified probe is valid. */ | |
2325 | p = __get_valid_kprobe(kp); | |
2326 | if (unlikely(p == NULL)) { | |
2327 | ret = -EINVAL; | |
2328 | goto out; | |
2329 | } | |
2330 | ||
2331 | if (kprobe_gone(kp)) { | |
2332 | /* This kprobe has gone, we couldn't enable it. */ | |
2333 | ret = -EINVAL; | |
2334 | goto out; | |
2335 | } | |
2336 | ||
2337 | if (p != kp) | |
2338 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
2339 | ||
2340 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
2341 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
12310e34 JY |
2342 | ret = arm_kprobe(p); |
2343 | if (ret) | |
2344 | p->flags |= KPROBE_FLAG_DISABLED; | |
c0614829 MH |
2345 | } |
2346 | out: | |
2347 | mutex_unlock(&kprobe_mutex); | |
2348 | return ret; | |
2349 | } | |
2350 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
2351 | ||
4458515b | 2352 | /* Caller must NOT call this in usual path. This is only for critical case */ |
820aede0 | 2353 | void dump_kprobe(struct kprobe *kp) |
24851d24 | 2354 | { |
9c89bb8e | 2355 | pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n", |
4458515b | 2356 | kp->symbol_name, kp->offset, kp->addr); |
24851d24 | 2357 | } |
820aede0 | 2358 | NOKPROBE_SYMBOL(dump_kprobe); |
24851d24 | 2359 | |
fb1a59fa MH |
2360 | int kprobe_add_ksym_blacklist(unsigned long entry) |
2361 | { | |
2362 | struct kprobe_blacklist_entry *ent; | |
2363 | unsigned long offset = 0, size = 0; | |
2364 | ||
2365 | if (!kernel_text_address(entry) || | |
2366 | !kallsyms_lookup_size_offset(entry, &size, &offset)) | |
2367 | return -EINVAL; | |
2368 | ||
2369 | ent = kmalloc(sizeof(*ent), GFP_KERNEL); | |
2370 | if (!ent) | |
2371 | return -ENOMEM; | |
2372 | ent->start_addr = entry; | |
2373 | ent->end_addr = entry + size; | |
2374 | INIT_LIST_HEAD(&ent->list); | |
2375 | list_add_tail(&ent->list, &kprobe_blacklist); | |
2376 | ||
2377 | return (int)size; | |
2378 | } | |
2379 | ||
2380 | /* Add all symbols in given area into kprobe blacklist */ | |
2381 | int kprobe_add_area_blacklist(unsigned long start, unsigned long end) | |
2382 | { | |
2383 | unsigned long entry; | |
2384 | int ret = 0; | |
2385 | ||
2386 | for (entry = start; entry < end; entry += ret) { | |
2387 | ret = kprobe_add_ksym_blacklist(entry); | |
2388 | if (ret < 0) | |
2389 | return ret; | |
2390 | if (ret == 0) /* In case of alias symbol */ | |
2391 | ret = 1; | |
2392 | } | |
2393 | return 0; | |
2394 | } | |
2395 | ||
1e6769b0 MH |
2396 | /* Remove all symbols in given area from kprobe blacklist */ |
2397 | static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) | |
2398 | { | |
2399 | struct kprobe_blacklist_entry *ent, *n; | |
2400 | ||
2401 | list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { | |
2402 | if (ent->start_addr < start || ent->start_addr >= end) | |
2403 | continue; | |
2404 | list_del(&ent->list); | |
2405 | kfree(ent); | |
2406 | } | |
2407 | } | |
2408 | ||
16db6264 MH |
2409 | static void kprobe_remove_ksym_blacklist(unsigned long entry) |
2410 | { | |
2411 | kprobe_remove_area_blacklist(entry, entry + 1); | |
2412 | } | |
2413 | ||
d002b8bc AH |
2414 | int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, |
2415 | char *type, char *sym) | |
2416 | { | |
2417 | return -ERANGE; | |
2418 | } | |
2419 | ||
2420 | int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, | |
2421 | char *sym) | |
2422 | { | |
2423 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT | |
2424 | if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym)) | |
2425 | return 0; | |
2426 | #ifdef CONFIG_OPTPROBES | |
2427 | if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym)) | |
2428 | return 0; | |
2429 | #endif | |
2430 | #endif | |
2431 | if (!arch_kprobe_get_kallsym(&symnum, value, type, sym)) | |
2432 | return 0; | |
2433 | return -ERANGE; | |
2434 | } | |
2435 | ||
fb1a59fa MH |
2436 | int __init __weak arch_populate_kprobe_blacklist(void) |
2437 | { | |
2438 | return 0; | |
2439 | } | |
2440 | ||
376e2424 MH |
2441 | /* |
2442 | * Lookup and populate the kprobe_blacklist. | |
2443 | * | |
2444 | * Unlike the kretprobe blacklist, we'll need to determine | |
2445 | * the range of addresses that belong to the said functions, | |
2446 | * since a kprobe need not necessarily be at the beginning | |
2447 | * of a function. | |
2448 | */ | |
2449 | static int __init populate_kprobe_blacklist(unsigned long *start, | |
2450 | unsigned long *end) | |
2451 | { | |
fb1a59fa | 2452 | unsigned long entry; |
376e2424 | 2453 | unsigned long *iter; |
fb1a59fa | 2454 | int ret; |
376e2424 MH |
2455 | |
2456 | for (iter = start; iter < end; iter++) { | |
f2ec8d9a | 2457 | entry = (unsigned long)dereference_symbol_descriptor((void *)*iter); |
fb1a59fa MH |
2458 | ret = kprobe_add_ksym_blacklist(entry); |
2459 | if (ret == -EINVAL) | |
376e2424 | 2460 | continue; |
fb1a59fa MH |
2461 | if (ret < 0) |
2462 | return ret; | |
376e2424 | 2463 | } |
fb1a59fa | 2464 | |
223a76b2 | 2465 | /* Symbols in '__kprobes_text' are blacklisted */ |
fb1a59fa MH |
2466 | ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, |
2467 | (unsigned long)__kprobes_text_end); | |
66e9b071 TG |
2468 | if (ret) |
2469 | return ret; | |
2470 | ||
223a76b2 | 2471 | /* Symbols in 'noinstr' section are blacklisted */ |
66e9b071 TG |
2472 | ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start, |
2473 | (unsigned long)__noinstr_text_end); | |
fb1a59fa MH |
2474 | |
2475 | return ret ? : arch_populate_kprobe_blacklist(); | |
376e2424 MH |
2476 | } |
2477 | ||
1e6769b0 MH |
2478 | static void add_module_kprobe_blacklist(struct module *mod) |
2479 | { | |
2480 | unsigned long start, end; | |
16db6264 MH |
2481 | int i; |
2482 | ||
2483 | if (mod->kprobe_blacklist) { | |
2484 | for (i = 0; i < mod->num_kprobe_blacklist; i++) | |
2485 | kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]); | |
2486 | } | |
1e6769b0 MH |
2487 | |
2488 | start = (unsigned long)mod->kprobes_text_start; | |
2489 | if (start) { | |
2490 | end = start + mod->kprobes_text_size; | |
2491 | kprobe_add_area_blacklist(start, end); | |
2492 | } | |
66e9b071 TG |
2493 | |
2494 | start = (unsigned long)mod->noinstr_text_start; | |
2495 | if (start) { | |
2496 | end = start + mod->noinstr_text_size; | |
2497 | kprobe_add_area_blacklist(start, end); | |
2498 | } | |
1e6769b0 MH |
2499 | } |
2500 | ||
2501 | static void remove_module_kprobe_blacklist(struct module *mod) | |
2502 | { | |
2503 | unsigned long start, end; | |
16db6264 MH |
2504 | int i; |
2505 | ||
2506 | if (mod->kprobe_blacklist) { | |
2507 | for (i = 0; i < mod->num_kprobe_blacklist; i++) | |
2508 | kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]); | |
2509 | } | |
1e6769b0 MH |
2510 | |
2511 | start = (unsigned long)mod->kprobes_text_start; | |
2512 | if (start) { | |
2513 | end = start + mod->kprobes_text_size; | |
2514 | kprobe_remove_area_blacklist(start, end); | |
2515 | } | |
66e9b071 TG |
2516 | |
2517 | start = (unsigned long)mod->noinstr_text_start; | |
2518 | if (start) { | |
2519 | end = start + mod->noinstr_text_size; | |
2520 | kprobe_remove_area_blacklist(start, end); | |
2521 | } | |
1e6769b0 MH |
2522 | } |
2523 | ||
e8386a0c | 2524 | /* Module notifier call back, checking kprobes on the module */ |
55479f64 MH |
2525 | static int kprobes_module_callback(struct notifier_block *nb, |
2526 | unsigned long val, void *data) | |
e8386a0c MH |
2527 | { |
2528 | struct module *mod = data; | |
2529 | struct hlist_head *head; | |
e8386a0c MH |
2530 | struct kprobe *p; |
2531 | unsigned int i; | |
f24659d9 | 2532 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2533 | |
1e6769b0 MH |
2534 | if (val == MODULE_STATE_COMING) { |
2535 | mutex_lock(&kprobe_mutex); | |
2536 | add_module_kprobe_blacklist(mod); | |
2537 | mutex_unlock(&kprobe_mutex); | |
2538 | } | |
f24659d9 | 2539 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2540 | return NOTIFY_DONE; |
2541 | ||
2542 | /* | |
223a76b2 MH |
2543 | * When 'MODULE_STATE_GOING' was notified, both of module '.text' and |
2544 | * '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was | |
2545 | * notified, only '.init.text' section would be freed. We need to | |
f24659d9 | 2546 | * disable kprobes which have been inserted in the sections. |
e8386a0c MH |
2547 | */ |
2548 | mutex_lock(&kprobe_mutex); | |
2549 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2550 | head = &kprobe_table[i]; | |
7e6a71d8 | 2551 | hlist_for_each_entry(p, head, hlist) |
f24659d9 MH |
2552 | if (within_module_init((unsigned long)p->addr, mod) || |
2553 | (checkcore && | |
2554 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2555 | /* |
2556 | * The vaddr this probe is installed will soon | |
2557 | * be vfreed buy not synced to disk. Hence, | |
2558 | * disarming the breakpoint isn't needed. | |
545a0281 SRV |
2559 | * |
2560 | * Note, this will also move any optimized probes | |
2561 | * that are pending to be removed from their | |
223a76b2 | 2562 | * corresponding lists to the 'freeing_list' and |
545a0281 | 2563 | * will not be touched by the delayed |
223a76b2 | 2564 | * kprobe_optimizer() work handler. |
e8386a0c MH |
2565 | */ |
2566 | kill_kprobe(p); | |
2567 | } | |
2568 | } | |
1e6769b0 MH |
2569 | if (val == MODULE_STATE_GOING) |
2570 | remove_module_kprobe_blacklist(mod); | |
e8386a0c MH |
2571 | mutex_unlock(&kprobe_mutex); |
2572 | return NOTIFY_DONE; | |
2573 | } | |
2574 | ||
2575 | static struct notifier_block kprobe_module_nb = { | |
2576 | .notifier_call = kprobes_module_callback, | |
2577 | .priority = 0 | |
2578 | }; | |
2579 | ||
82d083ab MH |
2580 | void kprobe_free_init_mem(void) |
2581 | { | |
2582 | void *start = (void *)(&__init_begin); | |
2583 | void *end = (void *)(&__init_end); | |
2584 | struct hlist_head *head; | |
2585 | struct kprobe *p; | |
2586 | int i; | |
2587 | ||
2588 | mutex_lock(&kprobe_mutex); | |
2589 | ||
223a76b2 | 2590 | /* Kill all kprobes on initmem because the target code has been freed. */ |
82d083ab MH |
2591 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2592 | head = &kprobe_table[i]; | |
2593 | hlist_for_each_entry(p, head, hlist) { | |
2594 | if (start <= (void *)p->addr && (void *)p->addr < end) | |
2595 | kill_kprobe(p); | |
2596 | } | |
2597 | } | |
2598 | ||
2599 | mutex_unlock(&kprobe_mutex); | |
2600 | } | |
2601 | ||
1da177e4 LT |
2602 | static int __init init_kprobes(void) |
2603 | { | |
2604 | int i, err = 0; | |
2605 | ||
2606 | /* FIXME allocate the probe table, currently defined statically */ | |
2607 | /* initialize all list heads */ | |
d741bf41 | 2608 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) |
1da177e4 LT |
2609 | INIT_HLIST_HEAD(&kprobe_table[i]); |
2610 | ||
376e2424 MH |
2611 | err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
2612 | __stop_kprobe_blacklist); | |
223a76b2 | 2613 | if (err) |
9c89bb8e | 2614 | pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err); |
3d8d996e | 2615 | |
f438d914 MH |
2616 | if (kretprobe_blacklist_size) { |
2617 | /* lookup the function address from its name */ | |
2618 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
49e0b465 | 2619 | kretprobe_blacklist[i].addr = |
290e3070 | 2620 | kprobe_lookup_name(kretprobe_blacklist[i].name, 0); |
f438d914 | 2621 | if (!kretprobe_blacklist[i].addr) |
9c89bb8e | 2622 | pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n", |
f438d914 MH |
2623 | kretprobe_blacklist[i].name); |
2624 | } | |
2625 | } | |
2626 | ||
e579abeb MH |
2627 | /* By default, kprobes are armed */ |
2628 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2629 | |
c85c9a2c | 2630 | #if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
223a76b2 | 2631 | /* Init 'kprobe_optinsn_slots' for allocation */ |
c85c9a2c MH |
2632 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
2633 | #endif | |
2634 | ||
6772926b | 2635 | err = arch_init_kprobes(); |
802eae7c RL |
2636 | if (!err) |
2637 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
2638 | if (!err) |
2639 | err = register_module_notifier(&kprobe_module_nb); | |
2640 | ||
ef53d9c5 | 2641 | kprobes_initialized = (err == 0); |
a737a3c6 | 2642 | kprobe_sysctls_init(); |
1da177e4 LT |
2643 | return err; |
2644 | } | |
36dadef2 | 2645 | early_initcall(init_kprobes); |
1da177e4 | 2646 | |
c85c9a2c MH |
2647 | #if defined(CONFIG_OPTPROBES) |
2648 | static int __init init_optprobes(void) | |
2649 | { | |
2650 | /* | |
2651 | * Enable kprobe optimization - this kicks the optimizer which | |
2652 | * depends on synchronize_rcu_tasks() and ksoftirqd, that is | |
2653 | * not spawned in early initcall. So delay the optimization. | |
2654 | */ | |
2655 | optimize_all_kprobes(); | |
2656 | ||
2657 | return 0; | |
2658 | } | |
2659 | subsys_initcall(init_optprobes); | |
2660 | #endif | |
2661 | ||
346fd59b | 2662 | #ifdef CONFIG_DEBUG_FS |
55479f64 | 2663 | static void report_probe(struct seq_file *pi, struct kprobe *p, |
afd66255 | 2664 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2665 | { |
2666 | char *kprobe_type; | |
81365a94 | 2667 | void *addr = p->addr; |
346fd59b SD |
2668 | |
2669 | if (p->pre_handler == pre_handler_kretprobe) | |
2670 | kprobe_type = "r"; | |
346fd59b SD |
2671 | else |
2672 | kprobe_type = "k"; | |
afd66255 | 2673 | |
60f7bb66 | 2674 | if (!kallsyms_show_value(pi->file->f_cred)) |
81365a94 MH |
2675 | addr = NULL; |
2676 | ||
346fd59b | 2677 | if (sym) |
81365a94 MH |
2678 | seq_printf(pi, "%px %s %s+0x%x %s ", |
2679 | addr, kprobe_type, sym, offset, | |
afd66255 | 2680 | (modname ? modname : " ")); |
81365a94 MH |
2681 | else /* try to use %pS */ |
2682 | seq_printf(pi, "%px %s %pS ", | |
2683 | addr, kprobe_type, p->addr); | |
afd66255 MH |
2684 | |
2685 | if (!pp) | |
2686 | pp = p; | |
ae6aa16f | 2687 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2688 | (kprobe_gone(p) ? "[GONE]" : ""), |
2689 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2690 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2691 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2692 | } |
2693 | ||
55479f64 | 2694 | static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
346fd59b SD |
2695 | { |
2696 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2697 | } | |
2698 | ||
55479f64 | 2699 | static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
346fd59b SD |
2700 | { |
2701 | (*pos)++; | |
2702 | if (*pos >= KPROBE_TABLE_SIZE) | |
2703 | return NULL; | |
2704 | return pos; | |
2705 | } | |
2706 | ||
55479f64 | 2707 | static void kprobe_seq_stop(struct seq_file *f, void *v) |
346fd59b SD |
2708 | { |
2709 | /* Nothing to do */ | |
2710 | } | |
2711 | ||
55479f64 | 2712 | static int show_kprobe_addr(struct seq_file *pi, void *v) |
346fd59b SD |
2713 | { |
2714 | struct hlist_head *head; | |
346fd59b SD |
2715 | struct kprobe *p, *kp; |
2716 | const char *sym = NULL; | |
2717 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 2718 | unsigned long offset = 0; |
ab767865 | 2719 | char *modname, namebuf[KSYM_NAME_LEN]; |
346fd59b SD |
2720 | |
2721 | head = &kprobe_table[i]; | |
2722 | preempt_disable(); | |
b67bfe0d | 2723 | hlist_for_each_entry_rcu(p, head, hlist) { |
ffb45122 | 2724 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2725 | &offset, &modname, namebuf); |
afd66255 | 2726 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2727 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2728 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2729 | } else |
afd66255 | 2730 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2731 | } |
2732 | preempt_enable(); | |
2733 | return 0; | |
2734 | } | |
2735 | ||
eac2cece | 2736 | static const struct seq_operations kprobes_sops = { |
346fd59b SD |
2737 | .start = kprobe_seq_start, |
2738 | .next = kprobe_seq_next, | |
2739 | .stop = kprobe_seq_stop, | |
2740 | .show = show_kprobe_addr | |
2741 | }; | |
2742 | ||
eac2cece | 2743 | DEFINE_SEQ_ATTRIBUTE(kprobes); |
346fd59b | 2744 | |
63724740 MH |
2745 | /* kprobes/blacklist -- shows which functions can not be probed */ |
2746 | static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) | |
2747 | { | |
4fdd8887 | 2748 | mutex_lock(&kprobe_mutex); |
63724740 MH |
2749 | return seq_list_start(&kprobe_blacklist, *pos); |
2750 | } | |
2751 | ||
2752 | static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
2753 | { | |
2754 | return seq_list_next(v, &kprobe_blacklist, pos); | |
2755 | } | |
2756 | ||
2757 | static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) | |
2758 | { | |
2759 | struct kprobe_blacklist_entry *ent = | |
2760 | list_entry(v, struct kprobe_blacklist_entry, list); | |
2761 | ||
ffb9bd68 | 2762 | /* |
223a76b2 | 2763 | * If '/proc/kallsyms' is not showing kernel address, we won't |
ffb9bd68 MH |
2764 | * show them here either. |
2765 | */ | |
60f7bb66 | 2766 | if (!kallsyms_show_value(m->file->f_cred)) |
ffb9bd68 MH |
2767 | seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL, |
2768 | (void *)ent->start_addr); | |
2769 | else | |
2770 | seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr, | |
2771 | (void *)ent->end_addr, (void *)ent->start_addr); | |
63724740 MH |
2772 | return 0; |
2773 | } | |
2774 | ||
4fdd8887 MH |
2775 | static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v) |
2776 | { | |
2777 | mutex_unlock(&kprobe_mutex); | |
2778 | } | |
2779 | ||
eac2cece | 2780 | static const struct seq_operations kprobe_blacklist_sops = { |
63724740 MH |
2781 | .start = kprobe_blacklist_seq_start, |
2782 | .next = kprobe_blacklist_seq_next, | |
4fdd8887 | 2783 | .stop = kprobe_blacklist_seq_stop, |
63724740 MH |
2784 | .show = kprobe_blacklist_seq_show, |
2785 | }; | |
eac2cece | 2786 | DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist); |
63724740 | 2787 | |
12310e34 | 2788 | static int arm_all_kprobes(void) |
bf8f6e5b AM |
2789 | { |
2790 | struct hlist_head *head; | |
bf8f6e5b | 2791 | struct kprobe *p; |
12310e34 JY |
2792 | unsigned int i, total = 0, errors = 0; |
2793 | int err, ret = 0; | |
bf8f6e5b AM |
2794 | |
2795 | mutex_lock(&kprobe_mutex); | |
2796 | ||
e579abeb MH |
2797 | /* If kprobes are armed, just return */ |
2798 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2799 | goto already_enabled; |
2800 | ||
977ad481 WN |
2801 | /* |
2802 | * optimize_kprobe() called by arm_kprobe() checks | |
2803 | * kprobes_all_disarmed, so set kprobes_all_disarmed before | |
2804 | * arm_kprobe. | |
2805 | */ | |
2806 | kprobes_all_disarmed = false; | |
afd66255 | 2807 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2808 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2809 | head = &kprobe_table[i]; | |
12310e34 | 2810 | /* Arm all kprobes on a best-effort basis */ |
7e6a71d8 | 2811 | hlist_for_each_entry(p, head, hlist) { |
12310e34 JY |
2812 | if (!kprobe_disabled(p)) { |
2813 | err = arm_kprobe(p); | |
2814 | if (err) { | |
2815 | errors++; | |
2816 | ret = err; | |
2817 | } | |
2818 | total++; | |
2819 | } | |
2820 | } | |
bf8f6e5b AM |
2821 | } |
2822 | ||
12310e34 | 2823 | if (errors) |
9c89bb8e | 2824 | pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n", |
12310e34 JY |
2825 | errors, total); |
2826 | else | |
2827 | pr_info("Kprobes globally enabled\n"); | |
bf8f6e5b AM |
2828 | |
2829 | already_enabled: | |
2830 | mutex_unlock(&kprobe_mutex); | |
12310e34 | 2831 | return ret; |
bf8f6e5b AM |
2832 | } |
2833 | ||
297f9233 | 2834 | static int disarm_all_kprobes(void) |
bf8f6e5b AM |
2835 | { |
2836 | struct hlist_head *head; | |
bf8f6e5b | 2837 | struct kprobe *p; |
297f9233 JY |
2838 | unsigned int i, total = 0, errors = 0; |
2839 | int err, ret = 0; | |
bf8f6e5b AM |
2840 | |
2841 | mutex_lock(&kprobe_mutex); | |
2842 | ||
e579abeb | 2843 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2844 | if (kprobes_all_disarmed) { |
2845 | mutex_unlock(&kprobe_mutex); | |
297f9233 | 2846 | return 0; |
6274de49 | 2847 | } |
bf8f6e5b | 2848 | |
e579abeb | 2849 | kprobes_all_disarmed = true; |
afd66255 | 2850 | |
bf8f6e5b AM |
2851 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2852 | head = &kprobe_table[i]; | |
297f9233 | 2853 | /* Disarm all kprobes on a best-effort basis */ |
7e6a71d8 | 2854 | hlist_for_each_entry(p, head, hlist) { |
297f9233 JY |
2855 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) { |
2856 | err = disarm_kprobe(p, false); | |
2857 | if (err) { | |
2858 | errors++; | |
2859 | ret = err; | |
2860 | } | |
2861 | total++; | |
2862 | } | |
bf8f6e5b AM |
2863 | } |
2864 | } | |
297f9233 JY |
2865 | |
2866 | if (errors) | |
9c89bb8e | 2867 | pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n", |
297f9233 JY |
2868 | errors, total); |
2869 | else | |
2870 | pr_info("Kprobes globally disabled\n"); | |
2871 | ||
bf8f6e5b | 2872 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2873 | |
6274de49 MH |
2874 | /* Wait for disarming all kprobes by optimizer */ |
2875 | wait_for_kprobe_optimizer(); | |
297f9233 JY |
2876 | |
2877 | return ret; | |
bf8f6e5b AM |
2878 | } |
2879 | ||
2880 | /* | |
2881 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2882 | * when the bool state is switched. We can reuse that facility when | |
2883 | * available | |
2884 | */ | |
2885 | static ssize_t read_enabled_file_bool(struct file *file, | |
2886 | char __user *user_buf, size_t count, loff_t *ppos) | |
2887 | { | |
2888 | char buf[3]; | |
2889 | ||
e579abeb | 2890 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
2891 | buf[0] = '1'; |
2892 | else | |
2893 | buf[0] = '0'; | |
2894 | buf[1] = '\n'; | |
2895 | buf[2] = 0x00; | |
2896 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2897 | } | |
2898 | ||
2899 | static ssize_t write_enabled_file_bool(struct file *file, | |
2900 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2901 | { | |
5d6de7d7 PA |
2902 | bool enable; |
2903 | int ret; | |
bf8f6e5b | 2904 | |
5d6de7d7 PA |
2905 | ret = kstrtobool_from_user(user_buf, count, &enable); |
2906 | if (ret) | |
2907 | return ret; | |
bf8f6e5b | 2908 | |
5d6de7d7 | 2909 | ret = enable ? arm_all_kprobes() : disarm_all_kprobes(); |
12310e34 JY |
2910 | if (ret) |
2911 | return ret; | |
2912 | ||
bf8f6e5b AM |
2913 | return count; |
2914 | } | |
2915 | ||
828c0950 | 2916 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2917 | .read = read_enabled_file_bool, |
2918 | .write = write_enabled_file_bool, | |
6038f373 | 2919 | .llseek = default_llseek, |
bf8f6e5b AM |
2920 | }; |
2921 | ||
55479f64 | 2922 | static int __init debugfs_kprobe_init(void) |
346fd59b | 2923 | { |
8c0fd1fa | 2924 | struct dentry *dir; |
346fd59b SD |
2925 | |
2926 | dir = debugfs_create_dir("kprobes", NULL); | |
346fd59b | 2927 | |
eac2cece | 2928 | debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops); |
346fd59b | 2929 | |
8f7262cd | 2930 | debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp); |
63724740 | 2931 | |
8c0fd1fa | 2932 | debugfs_create_file("blacklist", 0400, dir, NULL, |
eac2cece | 2933 | &kprobe_blacklist_fops); |
bf8f6e5b | 2934 | |
346fd59b SD |
2935 | return 0; |
2936 | } | |
2937 | ||
2938 | late_initcall(debugfs_kprobe_init); | |
2939 | #endif /* CONFIG_DEBUG_FS */ |