Commit | Line | Data |
---|---|---|
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> |
3a872d89 | 29 | #include <linux/kallsyms.h> |
b4c6c34a | 30 | #include <linux/freezer.h> |
346fd59b SD |
31 | #include <linux/seq_file.h> |
32 | #include <linux/debugfs.h> | |
b2be84df | 33 | #include <linux/sysctl.h> |
1eeb66a1 | 34 | #include <linux/kdebug.h> |
4460fdad | 35 | #include <linux/memory.h> |
4554dbcb | 36 | #include <linux/ftrace.h> |
afd66255 | 37 | #include <linux/cpu.h> |
bf5438fc | 38 | #include <linux/jump_label.h> |
fa68bd09 | 39 | #include <linux/static_call.h> |
69e49088 | 40 | #include <linux/perf_event.h> |
12af2b83 | 41 | #include <linux/execmem.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 | 115 | /* |
12af2b83 | 116 | * Use execmem_alloc() so this page is within +/- 2GB of where the |
223a76b2 MH |
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 | */ | |
12af2b83 | 121 | return execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE); |
af96397d HC |
122 | } |
123 | ||
66ce7514 | 124 | static void free_insn_page(void *page) |
af96397d | 125 | { |
12af2b83 | 126 | execmem_free(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 */ |
f1c97a1b | 461 | 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 | ||
4fbd2f83 MHG |
558 | if (!list_empty(&unoptimizing_list)) |
559 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); | |
6274de49 | 560 | |
4fbd2f83 | 561 | /* Loop on 'freeing_list' for disarming and removing from kprobe hash list */ |
7b959fc5 | 562 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
f66c0447 MH |
563 | /* Switching from detour code to origin */ |
564 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
4fbd2f83 MHG |
565 | /* Disarm probes if marked disabled and not gone */ |
566 | if (kprobe_disabled(&op->kp) && !kprobe_gone(&op->kp)) | |
6274de49 MH |
567 | arch_disarm_kprobe(&op->kp); |
568 | if (kprobe_unused(&op->kp)) { | |
569 | /* | |
570 | * Remove unused probes from hash list. After waiting | |
571 | * for synchronization, these probes are reclaimed. | |
223a76b2 | 572 | * (reclaiming is done by do_free_cleaned_kprobes().) |
6274de49 MH |
573 | */ |
574 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
575 | } else |
576 | list_del_init(&op->list); | |
577 | } | |
6274de49 MH |
578 | } |
579 | ||
223a76b2 | 580 | /* Reclaim all kprobes on the 'freeing_list' */ |
55479f64 | 581 | static void do_free_cleaned_kprobes(void) |
6274de49 MH |
582 | { |
583 | struct optimized_kprobe *op, *tmp; | |
584 | ||
7b959fc5 | 585 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 | 586 | list_del_init(&op->list); |
cbdd96f5 MH |
587 | if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) { |
588 | /* | |
589 | * This must not happen, but if there is a kprobe | |
590 | * still in use, keep it on kprobes hash list. | |
591 | */ | |
592 | continue; | |
593 | } | |
6274de49 MH |
594 | free_aggr_kprobe(&op->kp); |
595 | } | |
596 | } | |
597 | ||
598 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
55479f64 | 599 | static void kick_kprobe_optimizer(void) |
6274de49 | 600 | { |
ad72b3be | 601 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de49 MH |
602 | } |
603 | ||
61f4e13f | 604 | /* Kprobe jump optimizer */ |
55479f64 | 605 | static void kprobe_optimizer(struct work_struct *work) |
61f4e13f | 606 | { |
72ef3794 | 607 | mutex_lock(&kprobe_mutex); |
2d1e38f5 | 608 | cpus_read_lock(); |
f1c6ece2 | 609 | mutex_lock(&text_mutex); |
61f4e13f MH |
610 | |
611 | /* | |
6274de49 MH |
612 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
613 | * kprobes before waiting for quiesence period. | |
614 | */ | |
7b959fc5 | 615 | do_unoptimize_kprobes(); |
6274de49 MH |
616 | |
617 | /* | |
a30b85df MH |
618 | * Step 2: Wait for quiesence period to ensure all potentially |
619 | * preempted tasks to have normally scheduled. Because optprobe | |
620 | * may modify multiple instructions, there is a chance that Nth | |
621 | * instruction is preempted. In that case, such tasks can return | |
622 | * to 2nd-Nth byte of jump instruction. This wait is for avoiding it. | |
623 | * Note that on non-preemptive kernel, this is transparently converted | |
624 | * to synchronoze_sched() to wait for all interrupts to have completed. | |
61f4e13f | 625 | */ |
a30b85df | 626 | synchronize_rcu_tasks(); |
61f4e13f | 627 | |
6274de49 | 628 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 629 | do_optimize_kprobes(); |
6274de49 MH |
630 | |
631 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
7b959fc5 | 632 | do_free_cleaned_kprobes(); |
6274de49 | 633 | |
f1c6ece2 | 634 | mutex_unlock(&text_mutex); |
2d1e38f5 | 635 | cpus_read_unlock(); |
6274de49 | 636 | |
cd7ebe22 | 637 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 638 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 | 639 | kick_kprobe_optimizer(); |
1a0aa991 MH |
640 | |
641 | mutex_unlock(&kprobe_mutex); | |
6274de49 MH |
642 | } |
643 | ||
644 | /* Wait for completing optimization and unoptimization */ | |
30e7d894 | 645 | void wait_for_kprobe_optimizer(void) |
6274de49 | 646 | { |
ad72b3be TH |
647 | mutex_lock(&kprobe_mutex); |
648 | ||
649 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { | |
650 | mutex_unlock(&kprobe_mutex); | |
651 | ||
223a76b2 | 652 | /* This will also make 'optimizing_work' execute immmediately */ |
ad72b3be | 653 | flush_delayed_work(&optimizing_work); |
223a76b2 | 654 | /* 'optimizing_work' might not have been queued yet, relax */ |
ad72b3be TH |
655 | cpu_relax(); |
656 | ||
657 | mutex_lock(&kprobe_mutex); | |
658 | } | |
659 | ||
660 | mutex_unlock(&kprobe_mutex); | |
afd66255 MH |
661 | } |
662 | ||
868a6fc0 | 663 | bool optprobe_queued_unopt(struct optimized_kprobe *op) |
e4add247 MH |
664 | { |
665 | struct optimized_kprobe *_op; | |
666 | ||
667 | list_for_each_entry(_op, &unoptimizing_list, list) { | |
668 | if (op == _op) | |
669 | return true; | |
670 | } | |
671 | ||
672 | return false; | |
673 | } | |
674 | ||
afd66255 | 675 | /* Optimize kprobe if p is ready to be optimized */ |
55479f64 | 676 | static void optimize_kprobe(struct kprobe *p) |
afd66255 MH |
677 | { |
678 | struct optimized_kprobe *op; | |
679 | ||
680 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 681 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
682 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
683 | return; | |
684 | ||
223a76b2 | 685 | /* kprobes with 'post_handler' can not be optimized */ |
059053a2 | 686 | if (p->post_handler) |
afd66255 MH |
687 | return; |
688 | ||
689 | op = container_of(p, struct optimized_kprobe, kp); | |
690 | ||
691 | /* Check there is no other kprobes at the optimized instructions */ | |
692 | if (arch_check_optimized_kprobe(op) < 0) | |
693 | return; | |
694 | ||
695 | /* Check if it is already optimized. */ | |
e4add247 MH |
696 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) { |
697 | if (optprobe_queued_unopt(op)) { | |
698 | /* This is under unoptimizing. Just dequeue the probe */ | |
699 | list_del_init(&op->list); | |
700 | } | |
afd66255 | 701 | return; |
e4add247 | 702 | } |
afd66255 | 703 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 | 704 | |
223a76b2 MH |
705 | /* |
706 | * On the 'unoptimizing_list' and 'optimizing_list', | |
707 | * 'op' must have OPTIMIZED flag | |
708 | */ | |
e4add247 MH |
709 | if (WARN_ON_ONCE(!list_empty(&op->list))) |
710 | return; | |
711 | ||
712 | list_add(&op->list, &optimizing_list); | |
713 | kick_kprobe_optimizer(); | |
6274de49 MH |
714 | } |
715 | ||
716 | /* Short cut to direct unoptimizing */ | |
55479f64 | 717 | static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
6274de49 | 718 | { |
2d1e38f5 | 719 | lockdep_assert_cpus_held(); |
6274de49 | 720 | arch_unoptimize_kprobe(op); |
f66c0447 | 721 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
afd66255 MH |
722 | } |
723 | ||
724 | /* Unoptimize a kprobe if p is optimized */ | |
55479f64 | 725 | static void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
726 | { |
727 | struct optimized_kprobe *op; | |
728 | ||
6274de49 MH |
729 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
730 | return; /* This is not an optprobe nor optimized */ | |
731 | ||
732 | op = container_of(p, struct optimized_kprobe, kp); | |
e4add247 | 733 | if (!kprobe_optimized(p)) |
6274de49 | 734 | return; |
6274de49 | 735 | |
6274de49 | 736 | if (!list_empty(&op->list)) { |
e4add247 MH |
737 | if (optprobe_queued_unopt(op)) { |
738 | /* Queued in unoptimizing queue */ | |
739 | if (force) { | |
740 | /* | |
741 | * Forcibly unoptimize the kprobe here, and queue it | |
742 | * in the freeing list for release afterwards. | |
743 | */ | |
744 | force_unoptimize_kprobe(op); | |
745 | list_move(&op->list, &freeing_list); | |
746 | } | |
747 | } else { | |
748 | /* Dequeue from the optimizing queue */ | |
749 | list_del_init(&op->list); | |
750 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
751 | } | |
6274de49 MH |
752 | return; |
753 | } | |
e4add247 | 754 | |
6274de49 | 755 | /* Optimized kprobe case */ |
e4add247 | 756 | if (force) { |
6274de49 MH |
757 | /* Forcibly update the code: this is a special case */ |
758 | force_unoptimize_kprobe(op); | |
e4add247 | 759 | } else { |
6274de49 MH |
760 | list_add(&op->list, &unoptimizing_list); |
761 | kick_kprobe_optimizer(); | |
afd66255 MH |
762 | } |
763 | } | |
764 | ||
0490cd1f | 765 | /* Cancel unoptimizing for reusing */ |
819319fc | 766 | static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f MH |
767 | { |
768 | struct optimized_kprobe *op; | |
769 | ||
0490cd1f MH |
770 | /* |
771 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
772 | * there is still a relative jump) and disabled. | |
773 | */ | |
774 | op = container_of(ap, struct optimized_kprobe, kp); | |
4458515b | 775 | WARN_ON_ONCE(list_empty(&op->list)); |
0490cd1f MH |
776 | /* Enable the probe again */ |
777 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
223a76b2 | 778 | /* Optimize it again. (remove from 'op->list') */ |
5f843ed4 MH |
779 | if (!kprobe_optready(ap)) |
780 | return -EINVAL; | |
819319fc | 781 | |
0490cd1f | 782 | optimize_kprobe(ap); |
819319fc | 783 | return 0; |
0490cd1f MH |
784 | } |
785 | ||
afd66255 | 786 | /* Remove optimized instructions */ |
55479f64 | 787 | static void kill_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
788 | { |
789 | struct optimized_kprobe *op; | |
790 | ||
791 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
792 | if (!list_empty(&op->list)) |
793 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 794 | list_del_init(&op->list); |
6274de49 | 795 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc5 MH |
796 | |
797 | if (kprobe_unused(p)) { | |
7b959fc5 | 798 | /* |
4fbd2f83 MHG |
799 | * Unused kprobe is on unoptimizing or freeing list. We move it |
800 | * to freeing_list and let the kprobe_optimizer() remove it from | |
801 | * the kprobe hash list and free it. | |
7b959fc5 | 802 | */ |
4fbd2f83 MHG |
803 | if (optprobe_queued_unopt(op)) |
804 | list_move(&op->list, &freeing_list); | |
7b959fc5 MH |
805 | } |
806 | ||
6274de49 | 807 | /* Don't touch the code, because it is already freed. */ |
afd66255 MH |
808 | arch_remove_optimized_kprobe(op); |
809 | } | |
810 | ||
a460246c MH |
811 | static inline |
812 | void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) | |
813 | { | |
814 | if (!kprobe_ftrace(p)) | |
815 | arch_prepare_optimized_kprobe(op, p); | |
816 | } | |
817 | ||
afd66255 | 818 | /* Try to prepare optimized instructions */ |
55479f64 | 819 | static void prepare_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
820 | { |
821 | struct optimized_kprobe *op; | |
822 | ||
823 | op = container_of(p, struct optimized_kprobe, kp); | |
a460246c | 824 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
825 | } |
826 | ||
223a76b2 | 827 | /* Allocate new optimized_kprobe and try to prepare optimized instructions. */ |
55479f64 | 828 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
829 | { |
830 | struct optimized_kprobe *op; | |
831 | ||
832 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
833 | if (!op) | |
834 | return NULL; | |
835 | ||
836 | INIT_LIST_HEAD(&op->list); | |
837 | op->kp.addr = p->addr; | |
a460246c | 838 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
839 | |
840 | return &op->kp; | |
841 | } | |
842 | ||
55479f64 | 843 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
afd66255 MH |
844 | |
845 | /* | |
223a76b2 MH |
846 | * Prepare an optimized_kprobe and optimize it. |
847 | * NOTE: 'p' must be a normal registered kprobe. | |
afd66255 | 848 | */ |
55479f64 | 849 | static void try_to_optimize_kprobe(struct kprobe *p) |
afd66255 MH |
850 | { |
851 | struct kprobe *ap; | |
852 | struct optimized_kprobe *op; | |
853 | ||
223a76b2 | 854 | /* Impossible to optimize ftrace-based kprobe. */ |
ae6aa16f MH |
855 | if (kprobe_ftrace(p)) |
856 | return; | |
857 | ||
223a76b2 | 858 | /* For preparing optimization, jump_label_text_reserved() is called. */ |
2d1e38f5 | 859 | cpus_read_lock(); |
25764288 MH |
860 | jump_label_lock(); |
861 | mutex_lock(&text_mutex); | |
862 | ||
afd66255 MH |
863 | ap = alloc_aggr_kprobe(p); |
864 | if (!ap) | |
25764288 | 865 | goto out; |
afd66255 MH |
866 | |
867 | op = container_of(ap, struct optimized_kprobe, kp); | |
868 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
223a76b2 | 869 | /* If failed to setup optimizing, fallback to kprobe. */ |
6274de49 MH |
870 | arch_remove_optimized_kprobe(op); |
871 | kfree(op); | |
25764288 | 872 | goto out; |
afd66255 MH |
873 | } |
874 | ||
875 | init_aggr_kprobe(ap, p); | |
223a76b2 | 876 | optimize_kprobe(ap); /* This just kicks optimizer thread. */ |
25764288 MH |
877 | |
878 | out: | |
879 | mutex_unlock(&text_mutex); | |
880 | jump_label_unlock(); | |
2d1e38f5 | 881 | cpus_read_unlock(); |
afd66255 MH |
882 | } |
883 | ||
55479f64 | 884 | static void optimize_all_kprobes(void) |
b2be84df MH |
885 | { |
886 | struct hlist_head *head; | |
b2be84df MH |
887 | struct kprobe *p; |
888 | unsigned int i; | |
889 | ||
5c51543b | 890 | mutex_lock(&kprobe_mutex); |
223a76b2 | 891 | /* If optimization is already allowed, just return. */ |
b2be84df | 892 | if (kprobes_allow_optimization) |
5c51543b | 893 | goto out; |
b2be84df | 894 | |
2d1e38f5 | 895 | cpus_read_lock(); |
b2be84df | 896 | kprobes_allow_optimization = true; |
b2be84df MH |
897 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
898 | head = &kprobe_table[i]; | |
7e6a71d8 | 899 | hlist_for_each_entry(p, head, hlist) |
b2be84df MH |
900 | if (!kprobe_disabled(p)) |
901 | optimize_kprobe(p); | |
902 | } | |
2d1e38f5 | 903 | cpus_read_unlock(); |
9c89bb8e | 904 | pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n"); |
5c51543b MH |
905 | out: |
906 | mutex_unlock(&kprobe_mutex); | |
b2be84df MH |
907 | } |
908 | ||
c85c9a2c | 909 | #ifdef CONFIG_SYSCTL |
55479f64 | 910 | static void unoptimize_all_kprobes(void) |
b2be84df MH |
911 | { |
912 | struct hlist_head *head; | |
b2be84df MH |
913 | struct kprobe *p; |
914 | unsigned int i; | |
915 | ||
5c51543b | 916 | mutex_lock(&kprobe_mutex); |
223a76b2 | 917 | /* If optimization is already prohibited, just return. */ |
5c51543b MH |
918 | if (!kprobes_allow_optimization) { |
919 | mutex_unlock(&kprobe_mutex); | |
b2be84df | 920 | return; |
5c51543b | 921 | } |
b2be84df | 922 | |
2d1e38f5 | 923 | cpus_read_lock(); |
b2be84df | 924 | kprobes_allow_optimization = false; |
b2be84df MH |
925 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
926 | head = &kprobe_table[i]; | |
7e6a71d8 | 927 | hlist_for_each_entry(p, head, hlist) { |
b2be84df | 928 | if (!kprobe_disabled(p)) |
6274de49 | 929 | unoptimize_kprobe(p, false); |
b2be84df MH |
930 | } |
931 | } | |
2d1e38f5 | 932 | cpus_read_unlock(); |
5c51543b MH |
933 | mutex_unlock(&kprobe_mutex); |
934 | ||
223a76b2 | 935 | /* Wait for unoptimizing completion. */ |
6274de49 | 936 | wait_for_kprobe_optimizer(); |
9c89bb8e | 937 | pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n"); |
b2be84df MH |
938 | } |
939 | ||
5c51543b | 940 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
a737a3c6 XN |
941 | static int sysctl_kprobes_optimization; |
942 | static int proc_kprobes_optimization_handler(struct ctl_table *table, | |
943 | int write, void *buffer, | |
944 | size_t *length, loff_t *ppos) | |
b2be84df MH |
945 | { |
946 | int ret; | |
947 | ||
5c51543b | 948 | mutex_lock(&kprobe_sysctl_mutex); |
b2be84df MH |
949 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
950 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
951 | ||
952 | if (sysctl_kprobes_optimization) | |
953 | optimize_all_kprobes(); | |
954 | else | |
955 | unoptimize_all_kprobes(); | |
5c51543b | 956 | mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df MH |
957 | |
958 | return ret; | |
959 | } | |
a737a3c6 XN |
960 | |
961 | static struct ctl_table kprobe_sysctls[] = { | |
962 | { | |
963 | .procname = "kprobes-optimization", | |
964 | .data = &sysctl_kprobes_optimization, | |
965 | .maxlen = sizeof(int), | |
966 | .mode = 0644, | |
967 | .proc_handler = proc_kprobes_optimization_handler, | |
968 | .extra1 = SYSCTL_ZERO, | |
969 | .extra2 = SYSCTL_ONE, | |
970 | }, | |
a737a3c6 XN |
971 | }; |
972 | ||
973 | static void __init kprobe_sysctls_init(void) | |
974 | { | |
975 | register_sysctl_init("debug", kprobe_sysctls); | |
976 | } | |
b2be84df MH |
977 | #endif /* CONFIG_SYSCTL */ |
978 | ||
57d4e317 | 979 | /* Put a breakpoint for a probe. */ |
55479f64 | 980 | static void __arm_kprobe(struct kprobe *p) |
afd66255 | 981 | { |
6d8e40a8 | 982 | struct kprobe *_p; |
afd66255 | 983 | |
57d4e317 MH |
984 | lockdep_assert_held(&text_mutex); |
985 | ||
223a76b2 | 986 | /* Find the overlapping optimized kprobes. */ |
c42421e2 | 987 | _p = get_optimized_kprobe(p->addr); |
6d8e40a8 | 988 | if (unlikely(_p)) |
6274de49 MH |
989 | /* Fallback to unoptimized kprobe */ |
990 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
991 | |
992 | arch_arm_kprobe(p); | |
993 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
994 | } | |
995 | ||
57d4e317 | 996 | /* Remove the breakpoint of a probe. */ |
55479f64 | 997 | static void __disarm_kprobe(struct kprobe *p, bool reopt) |
afd66255 | 998 | { |
6d8e40a8 | 999 | struct kprobe *_p; |
afd66255 | 1000 | |
57d4e317 MH |
1001 | lockdep_assert_held(&text_mutex); |
1002 | ||
69d54b91 WN |
1003 | /* Try to unoptimize */ |
1004 | unoptimize_kprobe(p, kprobes_all_disarmed); | |
afd66255 | 1005 | |
6274de49 MH |
1006 | if (!kprobe_queued(p)) { |
1007 | arch_disarm_kprobe(p); | |
223a76b2 | 1008 | /* If another kprobe was blocked, re-optimize it. */ |
c42421e2 | 1009 | _p = get_optimized_kprobe(p->addr); |
6274de49 MH |
1010 | if (unlikely(_p) && reopt) |
1011 | optimize_kprobe(_p); | |
1012 | } | |
223a76b2 MH |
1013 | /* |
1014 | * TODO: Since unoptimization and real disarming will be done by | |
1015 | * the worker thread, we can not check whether another probe are | |
1016 | * unoptimized because of this probe here. It should be re-optimized | |
1017 | * by the worker thread. | |
1018 | */ | |
afd66255 MH |
1019 | } |
1020 | ||
1021 | #else /* !CONFIG_OPTPROBES */ | |
1022 | ||
1023 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 1024 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
1025 | #define kill_optimized_kprobe(p) do {} while (0) |
1026 | #define prepare_optimized_kprobe(p) do {} while (0) | |
1027 | #define try_to_optimize_kprobe(p) do {} while (0) | |
1028 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
1029 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
1030 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
1031 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 1032 | |
819319fc | 1033 | static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f | 1034 | { |
819319fc MH |
1035 | /* |
1036 | * If the optimized kprobe is NOT supported, the aggr kprobe is | |
1037 | * released at the same time that the last aggregated kprobe is | |
1038 | * unregistered. | |
1039 | * Thus there should be no chance to reuse unused kprobe. | |
1040 | */ | |
9c89bb8e | 1041 | WARN_ON_ONCE(1); |
819319fc | 1042 | return -EINVAL; |
0490cd1f MH |
1043 | } |
1044 | ||
55479f64 | 1045 | static void free_aggr_kprobe(struct kprobe *p) |
afd66255 | 1046 | { |
6274de49 | 1047 | arch_remove_kprobe(p); |
afd66255 MH |
1048 | kfree(p); |
1049 | } | |
1050 | ||
55479f64 | 1051 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
1052 | { |
1053 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
1054 | } | |
1055 | #endif /* CONFIG_OPTPROBES */ | |
1056 | ||
e7dbfe34 | 1057 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 1058 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
0bc11ed5 MH |
1059 | .func = kprobe_ftrace_handler, |
1060 | .flags = FTRACE_OPS_FL_SAVE_REGS, | |
1061 | }; | |
1062 | ||
1063 | static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = { | |
e5253896 | 1064 | .func = kprobe_ftrace_handler, |
1d70be34 | 1065 | .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
ae6aa16f | 1066 | }; |
0bc11ed5 MH |
1067 | |
1068 | static int kprobe_ipmodify_enabled; | |
ae6aa16f | 1069 | static int kprobe_ftrace_enabled; |
1a7d0890 | 1070 | bool kprobe_ftrace_disabled; |
ae6aa16f | 1071 | |
0bc11ed5 MH |
1072 | static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
1073 | int *cnt) | |
ae6aa16f | 1074 | { |
ed9492df | 1075 | int ret; |
ae6aa16f | 1076 | |
57d4e317 MH |
1077 | lockdep_assert_held(&kprobe_mutex); |
1078 | ||
0bc11ed5 | 1079 | ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); |
9c89bb8e | 1080 | if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret)) |
12310e34 | 1081 | return ret; |
12310e34 | 1082 | |
0bc11ed5 MH |
1083 | if (*cnt == 0) { |
1084 | ret = register_ftrace_function(ops); | |
9c89bb8e | 1085 | if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret)) |
12310e34 | 1086 | goto err_ftrace; |
ae6aa16f | 1087 | } |
12310e34 | 1088 | |
0bc11ed5 | 1089 | (*cnt)++; |
12310e34 JY |
1090 | return ret; |
1091 | ||
1092 | err_ftrace: | |
1093 | /* | |
0bc11ed5 MH |
1094 | * At this point, sinec ops is not registered, we should be sefe from |
1095 | * registering empty filter. | |
12310e34 | 1096 | */ |
0bc11ed5 | 1097 | ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
12310e34 | 1098 | return ret; |
ae6aa16f MH |
1099 | } |
1100 | ||
0bc11ed5 MH |
1101 | static int arm_kprobe_ftrace(struct kprobe *p) |
1102 | { | |
1103 | bool ipmodify = (p->post_handler != NULL); | |
1104 | ||
1105 | return __arm_kprobe_ftrace(p, | |
1106 | ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, | |
1107 | ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); | |
1108 | } | |
1109 | ||
0bc11ed5 MH |
1110 | static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
1111 | int *cnt) | |
ae6aa16f | 1112 | { |
ed9492df | 1113 | int ret; |
ae6aa16f | 1114 | |
57d4e317 MH |
1115 | lockdep_assert_held(&kprobe_mutex); |
1116 | ||
0bc11ed5 MH |
1117 | if (*cnt == 1) { |
1118 | ret = unregister_ftrace_function(ops); | |
9c89bb8e | 1119 | if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret)) |
297f9233 | 1120 | return ret; |
ae6aa16f | 1121 | } |
297f9233 | 1122 | |
0bc11ed5 | 1123 | (*cnt)--; |
297f9233 | 1124 | |
0bc11ed5 | 1125 | ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
9c89bb8e | 1126 | WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n", |
4458515b | 1127 | p->addr, ret); |
297f9233 | 1128 | return ret; |
ae6aa16f | 1129 | } |
0bc11ed5 MH |
1130 | |
1131 | static int disarm_kprobe_ftrace(struct kprobe *p) | |
1132 | { | |
1133 | bool ipmodify = (p->post_handler != NULL); | |
1134 | ||
1135 | return __disarm_kprobe_ftrace(p, | |
1136 | ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, | |
1137 | ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); | |
1138 | } | |
1a7d0890 | 1139 | |
4b377b48 | 1140 | void kprobe_ftrace_kill(void) |
1a7d0890 SB |
1141 | { |
1142 | kprobe_ftrace_disabled = true; | |
1143 | } | |
e7dbfe34 | 1144 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
10de795a MS |
1145 | static inline int arm_kprobe_ftrace(struct kprobe *p) |
1146 | { | |
1147 | return -ENODEV; | |
1148 | } | |
1149 | ||
1150 | static inline int disarm_kprobe_ftrace(struct kprobe *p) | |
1151 | { | |
1152 | return -ENODEV; | |
1153 | } | |
ae6aa16f MH |
1154 | #endif |
1155 | ||
02afb8d6 PA |
1156 | static int prepare_kprobe(struct kprobe *p) |
1157 | { | |
1158 | /* Must ensure p->addr is really on ftrace */ | |
1159 | if (kprobe_ftrace(p)) | |
1160 | return arch_prepare_kprobe_ftrace(p); | |
1161 | ||
1162 | return arch_prepare_kprobe(p); | |
1163 | } | |
1164 | ||
12310e34 | 1165 | static int arm_kprobe(struct kprobe *kp) |
201517a7 | 1166 | { |
12310e34 JY |
1167 | if (unlikely(kprobe_ftrace(kp))) |
1168 | return arm_kprobe_ftrace(kp); | |
1169 | ||
2d1e38f5 | 1170 | cpus_read_lock(); |
201517a7 | 1171 | mutex_lock(&text_mutex); |
afd66255 | 1172 | __arm_kprobe(kp); |
201517a7 | 1173 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1174 | cpus_read_unlock(); |
12310e34 JY |
1175 | |
1176 | return 0; | |
201517a7 MH |
1177 | } |
1178 | ||
297f9233 | 1179 | static int disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 1180 | { |
297f9233 JY |
1181 | if (unlikely(kprobe_ftrace(kp))) |
1182 | return disarm_kprobe_ftrace(kp); | |
2d1e38f5 TG |
1183 | |
1184 | cpus_read_lock(); | |
201517a7 | 1185 | mutex_lock(&text_mutex); |
ae6aa16f | 1186 | __disarm_kprobe(kp, reopt); |
201517a7 | 1187 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1188 | cpus_read_unlock(); |
297f9233 JY |
1189 | |
1190 | return 0; | |
201517a7 MH |
1191 | } |
1192 | ||
64f562c6 AM |
1193 | /* |
1194 | * Aggregate handlers for multiple kprobes support - these handlers | |
1195 | * take care of invoking the individual kprobe handlers on p->list | |
1196 | */ | |
820aede0 | 1197 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
1198 | { |
1199 | struct kprobe *kp; | |
1200 | ||
3516a460 | 1201 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1202 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1203 | set_kprobe_instance(kp); |
8b0914ea PP |
1204 | if (kp->pre_handler(kp, regs)) |
1205 | return 1; | |
64f562c6 | 1206 | } |
e6584523 | 1207 | reset_kprobe_instance(); |
64f562c6 AM |
1208 | } |
1209 | return 0; | |
1210 | } | |
820aede0 | 1211 | NOKPROBE_SYMBOL(aggr_pre_handler); |
64f562c6 | 1212 | |
820aede0 MH |
1213 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1214 | unsigned long flags) | |
64f562c6 AM |
1215 | { |
1216 | struct kprobe *kp; | |
1217 | ||
3516a460 | 1218 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1219 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1220 | set_kprobe_instance(kp); |
64f562c6 | 1221 | kp->post_handler(kp, regs, flags); |
e6584523 | 1222 | reset_kprobe_instance(); |
64f562c6 AM |
1223 | } |
1224 | } | |
64f562c6 | 1225 | } |
820aede0 | 1226 | NOKPROBE_SYMBOL(aggr_post_handler); |
64f562c6 | 1227 | |
223a76b2 | 1228 | /* Walks the list and increments 'nmissed' if 'p' has child probes. */ |
820aede0 | 1229 | void kprobes_inc_nmissed_count(struct kprobe *p) |
bf8d5c52 KA |
1230 | { |
1231 | struct kprobe *kp; | |
223a76b2 | 1232 | |
afd66255 | 1233 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1234 | p->nmissed++; |
1235 | } else { | |
1236 | list_for_each_entry_rcu(kp, &p->list, list) | |
1237 | kp->nmissed++; | |
1238 | } | |
bf8d5c52 | 1239 | } |
820aede0 | 1240 | NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
bf8d5c52 | 1241 | |
73f9b911 MH |
1242 | static struct kprobe kprobe_busy = { |
1243 | .addr = (void *) get_kprobe, | |
1244 | }; | |
1245 | ||
1246 | void kprobe_busy_begin(void) | |
1247 | { | |
1248 | struct kprobe_ctlblk *kcb; | |
1249 | ||
1250 | preempt_disable(); | |
1251 | __this_cpu_write(current_kprobe, &kprobe_busy); | |
1252 | kcb = get_kprobe_ctlblk(); | |
1253 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
1254 | } | |
1255 | ||
1256 | void kprobe_busy_end(void) | |
1257 | { | |
1258 | __this_cpu_write(current_kprobe, NULL); | |
1259 | preempt_enable(); | |
1260 | } | |
1261 | ||
223a76b2 | 1262 | /* Add the new probe to 'ap->list'. */ |
55479f64 | 1263 | static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1264 | { |
059053a2 | 1265 | if (p->post_handler) |
6274de49 | 1266 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1267 | |
059053a2 | 1268 | list_add_rcu(&p->list, &ap->list); |
b918e5e6 MH |
1269 | if (p->post_handler && !ap->post_handler) |
1270 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1271 | |
8b0914ea PP |
1272 | return 0; |
1273 | } | |
1274 | ||
64f562c6 | 1275 | /* |
223a76b2 MH |
1276 | * Fill in the required fields of the aggregator kprobe. Replace the |
1277 | * earlier kprobe in the hlist with the aggregator kprobe. | |
64f562c6 | 1278 | */ |
55479f64 | 1279 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1280 | { |
223a76b2 | 1281 | /* Copy the insn slot of 'p' to 'ap'. */ |
8b0914ea | 1282 | copy_kprobe(p, ap); |
a9ad965e | 1283 | flush_insn_slot(ap); |
64f562c6 | 1284 | ap->addr = p->addr; |
afd66255 | 1285 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1286 | ap->pre_handler = aggr_pre_handler; |
e8386a0c MH |
1287 | /* We don't care the kprobe which has gone. */ |
1288 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1289 | ap->post_handler = aggr_post_handler; |
64f562c6 AM |
1290 | |
1291 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1292 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1293 | |
afd66255 | 1294 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1295 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1296 | } |
1297 | ||
1298 | /* | |
223a76b2 | 1299 | * This registers the second or subsequent kprobe at the same address. |
64f562c6 | 1300 | */ |
55479f64 | 1301 | static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
64f562c6 AM |
1302 | { |
1303 | int ret = 0; | |
6d8e40a8 | 1304 | struct kprobe *ap = orig_p; |
64f562c6 | 1305 | |
2d1e38f5 TG |
1306 | cpus_read_lock(); |
1307 | ||
25764288 MH |
1308 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1309 | jump_label_lock(); | |
25764288 MH |
1310 | mutex_lock(&text_mutex); |
1311 | ||
6d8e40a8 | 1312 | if (!kprobe_aggrprobe(orig_p)) { |
223a76b2 | 1313 | /* If 'orig_p' is not an 'aggr_kprobe', create new one. */ |
6d8e40a8 | 1314 | ap = alloc_aggr_kprobe(orig_p); |
25764288 MH |
1315 | if (!ap) { |
1316 | ret = -ENOMEM; | |
1317 | goto out; | |
1318 | } | |
6d8e40a8 | 1319 | init_aggr_kprobe(ap, orig_p); |
819319fc | 1320 | } else if (kprobe_unused(ap)) { |
0490cd1f | 1321 | /* This probe is going to die. Rescue it */ |
819319fc MH |
1322 | ret = reuse_unused_kprobe(ap); |
1323 | if (ret) | |
1324 | goto out; | |
1325 | } | |
b918e5e6 MH |
1326 | |
1327 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1328 | /* |
1329 | * Attempting to insert new probe at the same location that | |
1330 | * had a probe in the module vaddr area which already | |
1331 | * freed. So, the instruction slot has already been | |
1332 | * released. We need a new slot for the new probe. | |
1333 | */ | |
b918e5e6 | 1334 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1335 | if (ret) |
b918e5e6 MH |
1336 | /* |
1337 | * Even if fail to allocate new slot, don't need to | |
223a76b2 MH |
1338 | * free the 'ap'. It will be used next time, or |
1339 | * freed by unregister_kprobe(). | |
b918e5e6 | 1340 | */ |
25764288 | 1341 | goto out; |
de5bd88d | 1342 | |
afd66255 MH |
1343 | /* Prepare optimized instructions if possible. */ |
1344 | prepare_optimized_kprobe(ap); | |
1345 | ||
e8386a0c | 1346 | /* |
de5bd88d MH |
1347 | * Clear gone flag to prevent allocating new slot again, and |
1348 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1349 | */ |
de5bd88d MH |
1350 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1351 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1352 | } |
b918e5e6 | 1353 | |
223a76b2 | 1354 | /* Copy the insn slot of 'p' to 'ap'. */ |
b918e5e6 | 1355 | copy_kprobe(ap, p); |
25764288 MH |
1356 | ret = add_new_kprobe(ap, p); |
1357 | ||
1358 | out: | |
1359 | mutex_unlock(&text_mutex); | |
25764288 | 1360 | jump_label_unlock(); |
2d1e38f5 | 1361 | cpus_read_unlock(); |
25764288 MH |
1362 | |
1363 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1364 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
12310e34 | 1365 | if (!kprobes_all_disarmed) { |
25764288 | 1366 | /* Arm the breakpoint again. */ |
12310e34 JY |
1367 | ret = arm_kprobe(ap); |
1368 | if (ret) { | |
1369 | ap->flags |= KPROBE_FLAG_DISABLED; | |
1370 | list_del_rcu(&p->list); | |
ae8b7ce7 | 1371 | synchronize_rcu(); |
12310e34 JY |
1372 | } |
1373 | } | |
25764288 MH |
1374 | } |
1375 | return ret; | |
64f562c6 AM |
1376 | } |
1377 | ||
be8f2743 MH |
1378 | bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
1379 | { | |
223a76b2 | 1380 | /* The '__kprobes' functions and entry code must not be probed. */ |
be8f2743 MH |
1381 | return addr >= (unsigned long)__kprobes_text_start && |
1382 | addr < (unsigned long)__kprobes_text_end; | |
1383 | } | |
1384 | ||
6143c6fb | 1385 | static bool __within_kprobe_blacklist(unsigned long addr) |
d0aaff97 | 1386 | { |
376e2424 | 1387 | struct kprobe_blacklist_entry *ent; |
3d8d996e | 1388 | |
be8f2743 | 1389 | if (arch_within_kprobe_blacklist(addr)) |
376e2424 | 1390 | return true; |
3d8d996e | 1391 | /* |
223a76b2 MH |
1392 | * If 'kprobe_blacklist' is defined, check the address and |
1393 | * reject any probe registration in the prohibited area. | |
3d8d996e | 1394 | */ |
376e2424 MH |
1395 | list_for_each_entry(ent, &kprobe_blacklist, list) { |
1396 | if (addr >= ent->start_addr && addr < ent->end_addr) | |
1397 | return true; | |
3d8d996e | 1398 | } |
6143c6fb MH |
1399 | return false; |
1400 | } | |
376e2424 | 1401 | |
6143c6fb MH |
1402 | bool within_kprobe_blacklist(unsigned long addr) |
1403 | { | |
1404 | char symname[KSYM_NAME_LEN], *p; | |
1405 | ||
1406 | if (__within_kprobe_blacklist(addr)) | |
1407 | return true; | |
1408 | ||
1409 | /* Check if the address is on a suffixed-symbol */ | |
1410 | if (!lookup_symbol_name(addr, symname)) { | |
1411 | p = strchr(symname, '.'); | |
1412 | if (!p) | |
1413 | return false; | |
1414 | *p = '\0'; | |
1415 | addr = (unsigned long)kprobe_lookup_name(symname, 0); | |
1416 | if (addr) | |
1417 | return __within_kprobe_blacklist(addr); | |
1418 | } | |
376e2424 | 1419 | return false; |
d0aaff97 PP |
1420 | } |
1421 | ||
cc66bb91 PZ |
1422 | /* |
1423 | * arch_adjust_kprobe_addr - adjust the address | |
1424 | * @addr: symbol base address | |
1425 | * @offset: offset within the symbol | |
1426 | * @on_func_entry: was this @addr+@offset on the function entry | |
1427 | * | |
1428 | * Typically returns @addr + @offset, except for special cases where the | |
1429 | * function might be prefixed by a CFI landing pad, in that case any offset | |
1430 | * inside the landing pad is mapped to the first 'real' instruction of the | |
1431 | * symbol. | |
1432 | * | |
1433 | * Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C | |
1434 | * instruction at +0. | |
1435 | */ | |
1436 | kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr, | |
1437 | unsigned long offset, | |
1438 | bool *on_func_entry) | |
1439 | { | |
1440 | *on_func_entry = !offset; | |
1441 | return (kprobe_opcode_t *)(addr + offset); | |
1442 | } | |
1443 | ||
b2a5cd69 | 1444 | /* |
223a76b2 | 1445 | * If 'symbol_name' is specified, look it up and add the 'offset' |
b2a5cd69 | 1446 | * to it. This way, we can specify a relative address to a symbol. |
bc81d48d MH |
1447 | * This returns encoded errors if it fails to look up symbol or invalid |
1448 | * combination of parameters. | |
b2a5cd69 | 1449 | */ |
cc66bb91 PZ |
1450 | static kprobe_opcode_t * |
1451 | _kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name, | |
1452 | unsigned long offset, bool *on_func_entry) | |
b2a5cd69 | 1453 | { |
1d585e70 | 1454 | if ((symbol_name && addr) || (!symbol_name && !addr)) |
bc81d48d MH |
1455 | goto invalid; |
1456 | ||
1d585e70 | 1457 | if (symbol_name) { |
cc66bb91 PZ |
1458 | /* |
1459 | * Input: @sym + @offset | |
1460 | * Output: @addr + @offset | |
1461 | * | |
1462 | * NOTE: kprobe_lookup_name() does *NOT* fold the offset | |
1463 | * argument into it's output! | |
1464 | */ | |
7246f600 | 1465 | addr = kprobe_lookup_name(symbol_name, offset); |
bc81d48d MH |
1466 | if (!addr) |
1467 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1468 | } |
1469 | ||
cc66bb91 PZ |
1470 | /* |
1471 | * So here we have @addr + @offset, displace it into a new | |
1472 | * @addr' + @offset' where @addr' is the symbol start address. | |
1473 | */ | |
1474 | addr = (void *)addr + offset; | |
1475 | if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset)) | |
1476 | return ERR_PTR(-ENOENT); | |
1477 | addr = (void *)addr - offset; | |
1478 | ||
1479 | /* | |
1480 | * Then ask the architecture to re-combine them, taking care of | |
1481 | * magical function entry details while telling us if this was indeed | |
1482 | * at the start of the function. | |
1483 | */ | |
1484 | addr = arch_adjust_kprobe_addr((unsigned long)addr, offset, on_func_entry); | |
bc81d48d MH |
1485 | if (addr) |
1486 | return addr; | |
1487 | ||
1488 | invalid: | |
1489 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1490 | } |
1491 | ||
1d585e70 NR |
1492 | static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
1493 | { | |
cc66bb91 PZ |
1494 | bool on_func_entry; |
1495 | return _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry); | |
1d585e70 NR |
1496 | } |
1497 | ||
223a76b2 MH |
1498 | /* |
1499 | * Check the 'p' is valid and return the aggregator kprobe | |
1500 | * at the same address. | |
1501 | */ | |
55479f64 | 1502 | static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
1f0ab409 | 1503 | { |
6d8e40a8 | 1504 | struct kprobe *ap, *list_p; |
1f0ab409 | 1505 | |
7e6a71d8 MH |
1506 | lockdep_assert_held(&kprobe_mutex); |
1507 | ||
6d8e40a8 MH |
1508 | ap = get_kprobe(p->addr); |
1509 | if (unlikely(!ap)) | |
1f0ab409 AM |
1510 | return NULL; |
1511 | ||
6d8e40a8 | 1512 | if (p != ap) { |
7e6a71d8 | 1513 | list_for_each_entry(list_p, &ap->list, list) |
1f0ab409 AM |
1514 | if (list_p == p) |
1515 | /* kprobe p is a valid probe */ | |
1516 | goto valid; | |
1517 | return NULL; | |
1518 | } | |
1519 | valid: | |
6d8e40a8 | 1520 | return ap; |
1f0ab409 AM |
1521 | } |
1522 | ||
33b1d146 MH |
1523 | /* |
1524 | * Warn and return error if the kprobe is being re-registered since | |
1525 | * there must be a software bug. | |
1526 | */ | |
1527 | static inline int warn_kprobe_rereg(struct kprobe *p) | |
1f0ab409 AM |
1528 | { |
1529 | int ret = 0; | |
1f0ab409 AM |
1530 | |
1531 | mutex_lock(&kprobe_mutex); | |
33b1d146 | 1532 | if (WARN_ON_ONCE(__get_valid_kprobe(p))) |
1f0ab409 AM |
1533 | ret = -EINVAL; |
1534 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1535 | |
1f0ab409 AM |
1536 | return ret; |
1537 | } | |
1538 | ||
4402deae | 1539 | static int check_ftrace_location(struct kprobe *p) |
1da177e4 | 1540 | { |
aebfd125 | 1541 | unsigned long addr = (unsigned long)p->addr; |
ae6aa16f | 1542 | |
aebfd125 | 1543 | if (ftrace_location(addr) == addr) { |
e7dbfe34 | 1544 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 1545 | p->flags |= KPROBE_FLAG_FTRACE; |
e7dbfe34 | 1546 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
1547 | return -EINVAL; |
1548 | #endif | |
1549 | } | |
f7f242ff HC |
1550 | return 0; |
1551 | } | |
1552 | ||
de02f2ac MHG |
1553 | static bool is_cfi_preamble_symbol(unsigned long addr) |
1554 | { | |
1555 | char symbuf[KSYM_NAME_LEN]; | |
1556 | ||
1557 | if (lookup_symbol_name(addr, symbuf)) | |
1558 | return false; | |
1559 | ||
1560 | return str_has_prefix("__cfi_", symbuf) || | |
1561 | str_has_prefix("__pfx_", symbuf); | |
1562 | } | |
1563 | ||
f7f242ff HC |
1564 | static int check_kprobe_address_safe(struct kprobe *p, |
1565 | struct module **probed_mod) | |
1566 | { | |
1567 | int ret; | |
1f0ab409 | 1568 | |
4402deae | 1569 | ret = check_ftrace_location(p); |
f7f242ff HC |
1570 | if (ret) |
1571 | return ret; | |
91bad2f8 | 1572 | jump_label_lock(); |
de31c3ca | 1573 | preempt_disable(); |
f7fa6ef0 | 1574 | |
325f3fb5 ZY |
1575 | /* Ensure the address is in a text area, and find a module if exists. */ |
1576 | *probed_mod = NULL; | |
1577 | if (!core_kernel_text((unsigned long) p->addr)) { | |
1578 | *probed_mod = __module_text_address((unsigned long) p->addr); | |
1579 | if (!(*probed_mod)) { | |
1580 | ret = -EINVAL; | |
1581 | goto out; | |
1582 | } | |
1583 | } | |
1584 | /* Ensure it is not in reserved area. */ | |
1585 | if (in_gate_area_no_mm((unsigned long) p->addr) || | |
376e2424 | 1586 | within_kprobe_blacklist((unsigned long) p->addr) || |
e336b402 | 1587 | jump_label_text_reserved(p->addr, p->addr) || |
fa68bd09 | 1588 | static_call_text_reserved(p->addr, p->addr) || |
de02f2ac MHG |
1589 | find_bug((unsigned long)p->addr) || |
1590 | is_cfi_preamble_symbol((unsigned long)p->addr)) { | |
f986a499 | 1591 | ret = -EINVAL; |
f7fa6ef0 | 1592 | goto out; |
f986a499 | 1593 | } |
b3e55c72 | 1594 | |
325f3fb5 | 1595 | /* Get module refcount and reject __init functions for loaded modules. */ |
7582b7be | 1596 | if (IS_ENABLED(CONFIG_MODULES) && *probed_mod) { |
6f716acd | 1597 | /* |
e8386a0c MH |
1598 | * We must hold a refcount of the probed module while updating |
1599 | * its code to prohibit unexpected unloading. | |
df019b1d | 1600 | */ |
f7fa6ef0 MH |
1601 | if (unlikely(!try_module_get(*probed_mod))) { |
1602 | ret = -ENOENT; | |
1603 | goto out; | |
1604 | } | |
de31c3ca | 1605 | |
f24659d9 | 1606 | /* |
223a76b2 | 1607 | * If the module freed '.init.text', we couldn't insert |
f24659d9 MH |
1608 | * kprobes in there. |
1609 | */ | |
f7fa6ef0 | 1610 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
7582b7be | 1611 | !module_is_coming(*probed_mod)) { |
f7fa6ef0 MH |
1612 | module_put(*probed_mod); |
1613 | *probed_mod = NULL; | |
1614 | ret = -ENOENT; | |
f24659d9 | 1615 | } |
df019b1d | 1616 | } |
7582b7be | 1617 | |
f7fa6ef0 | 1618 | out: |
a189d035 | 1619 | preempt_enable(); |
de31c3ca | 1620 | jump_label_unlock(); |
1da177e4 | 1621 | |
f7fa6ef0 MH |
1622 | return ret; |
1623 | } | |
1624 | ||
55479f64 | 1625 | int register_kprobe(struct kprobe *p) |
f7fa6ef0 MH |
1626 | { |
1627 | int ret; | |
1628 | struct kprobe *old_p; | |
1629 | struct module *probed_mod; | |
1630 | kprobe_opcode_t *addr; | |
bf7a87f1 | 1631 | bool on_func_entry; |
f7fa6ef0 MH |
1632 | |
1633 | /* Adjust probe address from symbol */ | |
bf7a87f1 | 1634 | addr = _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry); |
f7fa6ef0 MH |
1635 | if (IS_ERR(addr)) |
1636 | return PTR_ERR(addr); | |
1637 | p->addr = addr; | |
1638 | ||
33b1d146 | 1639 | ret = warn_kprobe_rereg(p); |
f7fa6ef0 MH |
1640 | if (ret) |
1641 | return ret; | |
1642 | ||
1643 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ | |
1644 | p->flags &= KPROBE_FLAG_DISABLED; | |
3516a460 | 1645 | p->nmissed = 0; |
9861668f | 1646 | INIT_LIST_HEAD(&p->list); |
afd66255 | 1647 | |
f7fa6ef0 MH |
1648 | ret = check_kprobe_address_safe(p, &probed_mod); |
1649 | if (ret) | |
1650 | return ret; | |
1651 | ||
1652 | mutex_lock(&kprobe_mutex); | |
afd66255 | 1653 | |
bf7a87f1 JO |
1654 | if (on_func_entry) |
1655 | p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY; | |
1656 | ||
64f562c6 AM |
1657 | old_p = get_kprobe(p->addr); |
1658 | if (old_p) { | |
223a76b2 | 1659 | /* Since this may unoptimize 'old_p', locking 'text_mutex'. */ |
64f562c6 | 1660 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1661 | goto out; |
1662 | } | |
1da177e4 | 1663 | |
2d1e38f5 TG |
1664 | cpus_read_lock(); |
1665 | /* Prevent text modification */ | |
1666 | mutex_lock(&text_mutex); | |
ae6aa16f | 1667 | ret = prepare_kprobe(p); |
25764288 | 1668 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1669 | cpus_read_unlock(); |
6f716acd | 1670 | if (ret) |
afd66255 | 1671 | goto out; |
49a2a1b8 | 1672 | |
64f562c6 | 1673 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1674 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1675 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1676 | ||
12310e34 JY |
1677 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) { |
1678 | ret = arm_kprobe(p); | |
1679 | if (ret) { | |
1680 | hlist_del_rcu(&p->hlist); | |
ae8b7ce7 | 1681 | synchronize_rcu(); |
12310e34 JY |
1682 | goto out; |
1683 | } | |
1684 | } | |
afd66255 MH |
1685 | |
1686 | /* Try to optimize kprobe */ | |
1687 | try_to_optimize_kprobe(p); | |
1da177e4 | 1688 | out: |
7a7d1cf9 | 1689 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1690 | |
e8386a0c | 1691 | if (probed_mod) |
df019b1d | 1692 | module_put(probed_mod); |
e8386a0c | 1693 | |
1da177e4 LT |
1694 | return ret; |
1695 | } | |
99081ab5 | 1696 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1697 | |
223a76b2 | 1698 | /* Check if all probes on the 'ap' are disabled. */ |
29e8077a | 1699 | static bool aggr_kprobe_disabled(struct kprobe *ap) |
6f0f1dd7 MH |
1700 | { |
1701 | struct kprobe *kp; | |
1702 | ||
7e6a71d8 MH |
1703 | lockdep_assert_held(&kprobe_mutex); |
1704 | ||
1705 | list_for_each_entry(kp, &ap->list, list) | |
6f0f1dd7 MH |
1706 | if (!kprobe_disabled(kp)) |
1707 | /* | |
223a76b2 MH |
1708 | * Since there is an active probe on the list, |
1709 | * we can't disable this 'ap'. | |
6f0f1dd7 | 1710 | */ |
29e8077a | 1711 | return false; |
6f0f1dd7 | 1712 | |
29e8077a | 1713 | return true; |
6f0f1dd7 MH |
1714 | } |
1715 | ||
55479f64 | 1716 | static struct kprobe *__disable_kprobe(struct kprobe *p) |
6f0f1dd7 MH |
1717 | { |
1718 | struct kprobe *orig_p; | |
297f9233 | 1719 | int ret; |
6f0f1dd7 | 1720 | |
57d4e317 MH |
1721 | lockdep_assert_held(&kprobe_mutex); |
1722 | ||
6f0f1dd7 MH |
1723 | /* Get an original kprobe for return */ |
1724 | orig_p = __get_valid_kprobe(p); | |
1725 | if (unlikely(orig_p == NULL)) | |
297f9233 | 1726 | return ERR_PTR(-EINVAL); |
6f0f1dd7 MH |
1727 | |
1728 | if (!kprobe_disabled(p)) { | |
1729 | /* Disable probe if it is a child probe */ | |
1730 | if (p != orig_p) | |
1731 | p->flags |= KPROBE_FLAG_DISABLED; | |
1732 | ||
1733 | /* Try to disarm and disable this/parent probe */ | |
1734 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
69d54b91 | 1735 | /* |
9c80e799 KI |
1736 | * Don't be lazy here. Even if 'kprobes_all_disarmed' |
1737 | * is false, 'orig_p' might not have been armed yet. | |
1738 | * Note arm_all_kprobes() __tries__ to arm all kprobes | |
1739 | * on the best effort basis. | |
69d54b91 | 1740 | */ |
9c80e799 | 1741 | if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) { |
297f9233 JY |
1742 | ret = disarm_kprobe(orig_p, true); |
1743 | if (ret) { | |
1744 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1745 | return ERR_PTR(ret); | |
1746 | } | |
1747 | } | |
6f0f1dd7 MH |
1748 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1749 | } | |
1750 | } | |
1751 | ||
1752 | return orig_p; | |
1753 | } | |
1754 | ||
de5bd88d MH |
1755 | /* |
1756 | * Unregister a kprobe without a scheduler synchronization. | |
1757 | */ | |
55479f64 | 1758 | static int __unregister_kprobe_top(struct kprobe *p) |
de5bd88d | 1759 | { |
6d8e40a8 | 1760 | struct kprobe *ap, *list_p; |
de5bd88d | 1761 | |
6f0f1dd7 MH |
1762 | /* Disable kprobe. This will disarm it if needed. */ |
1763 | ap = __disable_kprobe(p); | |
297f9233 JY |
1764 | if (IS_ERR(ap)) |
1765 | return PTR_ERR(ap); | |
de5bd88d | 1766 | |
6f0f1dd7 | 1767 | if (ap == p) |
bf8f6e5b | 1768 | /* |
6f0f1dd7 MH |
1769 | * This probe is an independent(and non-optimized) kprobe |
1770 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1771 | */ |
6f0f1dd7 MH |
1772 | goto disarmed; |
1773 | ||
1774 | /* Following process expects this probe is an aggrprobe */ | |
1775 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1776 | ||
6274de49 MH |
1777 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1778 | /* | |
1779 | * !disarmed could be happen if the probe is under delayed | |
1780 | * unoptimizing. | |
1781 | */ | |
6f0f1dd7 MH |
1782 | goto disarmed; |
1783 | else { | |
1784 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1785 | if (p->post_handler && !kprobe_gone(p)) { |
7e6a71d8 | 1786 | list_for_each_entry(list_p, &ap->list, list) { |
9861668f MH |
1787 | if ((list_p != p) && (list_p->post_handler)) |
1788 | goto noclean; | |
1789 | } | |
5dd7caf0 LH |
1790 | /* |
1791 | * For the kprobe-on-ftrace case, we keep the | |
1792 | * post_handler setting to identify this aggrprobe | |
1793 | * armed with kprobe_ipmodify_ops. | |
1794 | */ | |
1795 | if (!kprobe_ftrace(ap)) | |
1796 | ap->post_handler = NULL; | |
9861668f MH |
1797 | } |
1798 | noclean: | |
6f0f1dd7 MH |
1799 | /* |
1800 | * Remove from the aggrprobe: this path will do nothing in | |
1801 | * __unregister_kprobe_bottom(). | |
1802 | */ | |
49a2a1b8 | 1803 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1804 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1805 | /* | |
1806 | * Try to optimize this probe again, because post | |
1807 | * handler may have been changed. | |
1808 | */ | |
1809 | optimize_kprobe(ap); | |
49a2a1b8 | 1810 | } |
9861668f | 1811 | return 0; |
6f0f1dd7 MH |
1812 | |
1813 | disarmed: | |
1814 | hlist_del_rcu(&ap->hlist); | |
1815 | return 0; | |
9861668f | 1816 | } |
3516a460 | 1817 | |
55479f64 | 1818 | static void __unregister_kprobe_bottom(struct kprobe *p) |
9861668f | 1819 | { |
6d8e40a8 | 1820 | struct kprobe *ap; |
b3e55c72 | 1821 | |
e8386a0c | 1822 | if (list_empty(&p->list)) |
6274de49 | 1823 | /* This is an independent kprobe */ |
0498b635 | 1824 | arch_remove_kprobe(p); |
e8386a0c | 1825 | else if (list_is_singular(&p->list)) { |
6274de49 | 1826 | /* This is the last child of an aggrprobe */ |
6d8e40a8 | 1827 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1828 | list_del(&p->list); |
6d8e40a8 | 1829 | free_aggr_kprobe(ap); |
9861668f | 1830 | } |
6274de49 | 1831 | /* Otherwise, do nothing. */ |
9861668f MH |
1832 | } |
1833 | ||
55479f64 | 1834 | int register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1835 | { |
1836 | int i, ret = 0; | |
1837 | ||
1838 | if (num <= 0) | |
1839 | return -EINVAL; | |
1840 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1841 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1842 | if (ret < 0) { |
1843 | if (i > 0) | |
1844 | unregister_kprobes(kps, i); | |
9861668f | 1845 | break; |
36721656 | 1846 | } |
49a2a1b8 | 1847 | } |
9861668f MH |
1848 | return ret; |
1849 | } | |
99081ab5 | 1850 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1851 | |
55479f64 | 1852 | void unregister_kprobe(struct kprobe *p) |
9861668f MH |
1853 | { |
1854 | unregister_kprobes(&p, 1); | |
1855 | } | |
99081ab5 | 1856 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1857 | |
55479f64 | 1858 | void unregister_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1859 | { |
1860 | int i; | |
1861 | ||
1862 | if (num <= 0) | |
1863 | return; | |
1864 | mutex_lock(&kprobe_mutex); | |
1865 | for (i = 0; i < num; i++) | |
1866 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1867 | kps[i]->addr = NULL; | |
1868 | mutex_unlock(&kprobe_mutex); | |
1869 | ||
ae8b7ce7 | 1870 | synchronize_rcu(); |
9861668f MH |
1871 | for (i = 0; i < num; i++) |
1872 | if (kps[i]->addr) | |
1873 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1874 | } |
99081ab5 | 1875 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 | 1876 | |
5f6bee34 NR |
1877 | int __weak kprobe_exceptions_notify(struct notifier_block *self, |
1878 | unsigned long val, void *data) | |
fc62d020 NR |
1879 | { |
1880 | return NOTIFY_DONE; | |
1881 | } | |
5f6bee34 | 1882 | NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
fc62d020 | 1883 | |
1da177e4 | 1884 | static struct notifier_block kprobe_exceptions_nb = { |
3d5631e0 AK |
1885 | .notifier_call = kprobe_exceptions_notify, |
1886 | .priority = 0x7fffffff /* we need to be notified first */ | |
1887 | }; | |
1888 | ||
9edddaa2 | 1889 | #ifdef CONFIG_KRETPROBES |
66ada2cc | 1890 | |
73f9b911 | 1891 | #if !defined(CONFIG_KRETPROBE_ON_RETHOOK) |
4bbd9345 | 1892 | |
1893 | /* callbacks for objpool of kretprobe instances */ | |
1894 | static int kretprobe_init_inst(void *nod, void *context) | |
1895 | { | |
1896 | struct kretprobe_instance *ri = nod; | |
1897 | ||
1898 | ri->rph = context; | |
1899 | return 0; | |
1900 | } | |
1901 | static int kretprobe_fini_pool(struct objpool_head *head, void *context) | |
1902 | { | |
1903 | kfree(context); | |
1904 | return 0; | |
1905 | } | |
1906 | ||
43994049 MH |
1907 | static void free_rp_inst_rcu(struct rcu_head *head) |
1908 | { | |
1909 | struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu); | |
4bbd9345 | 1910 | struct kretprobe_holder *rph = ri->rph; |
43994049 | 1911 | |
4bbd9345 | 1912 | objpool_drop(ri, &rph->pool); |
43994049 MH |
1913 | } |
1914 | NOKPROBE_SYMBOL(free_rp_inst_rcu); | |
1915 | ||
1916 | static void recycle_rp_inst(struct kretprobe_instance *ri) | |
1917 | { | |
1918 | struct kretprobe *rp = get_kretprobe(ri); | |
1919 | ||
1920 | if (likely(rp)) | |
4bbd9345 | 1921 | objpool_push(ri, &rp->rph->pool); |
43994049 MH |
1922 | else |
1923 | call_rcu(&ri->rcu, free_rp_inst_rcu); | |
1924 | } | |
1925 | NOKPROBE_SYMBOL(recycle_rp_inst); | |
1926 | ||
1927 | /* | |
1928 | * This function is called from delayed_put_task_struct() when a task is | |
1929 | * dead and cleaned up to recycle any kretprobe instances associated with | |
1930 | * this task. These left over instances represent probed functions that | |
1931 | * have been called but will never return. | |
1932 | */ | |
1933 | void kprobe_flush_task(struct task_struct *tk) | |
1934 | { | |
1935 | struct kretprobe_instance *ri; | |
1936 | struct llist_node *node; | |
1937 | ||
1938 | /* Early boot, not yet initialized. */ | |
1939 | if (unlikely(!kprobes_initialized)) | |
1940 | return; | |
1941 | ||
1942 | kprobe_busy_begin(); | |
1943 | ||
1944 | node = __llist_del_all(&tk->kretprobe_instances); | |
1945 | while (node) { | |
1946 | ri = container_of(node, struct kretprobe_instance, llist); | |
1947 | node = node->next; | |
1948 | ||
1949 | recycle_rp_inst(ri); | |
1950 | } | |
1951 | ||
1952 | kprobe_busy_end(); | |
1953 | } | |
1954 | NOKPROBE_SYMBOL(kprobe_flush_task); | |
1955 | ||
1956 | static inline void free_rp_inst(struct kretprobe *rp) | |
1957 | { | |
4bbd9345 | 1958 | struct kretprobe_holder *rph = rp->rph; |
43994049 | 1959 | |
4bbd9345 | 1960 | if (!rph) |
1961 | return; | |
1962 | rp->rph = NULL; | |
1963 | objpool_fini(&rph->pool); | |
43994049 MH |
1964 | } |
1965 | ||
03bac0df MH |
1966 | /* This assumes the 'tsk' is the current task or the is not running. */ |
1967 | static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk, | |
1968 | struct llist_node **cur) | |
3d7e3382 | 1969 | { |
d741bf41 | 1970 | struct kretprobe_instance *ri = NULL; |
03bac0df MH |
1971 | struct llist_node *node = *cur; |
1972 | ||
1973 | if (!node) | |
1974 | node = tsk->kretprobe_instances.first; | |
1975 | else | |
1976 | node = node->next; | |
66ada2cc | 1977 | |
d741bf41 PZ |
1978 | while (node) { |
1979 | ri = container_of(node, struct kretprobe_instance, llist); | |
96fed8ac | 1980 | if (ri->ret_addr != kretprobe_trampoline_addr()) { |
03bac0df MH |
1981 | *cur = node; |
1982 | return ri->ret_addr; | |
d741bf41 | 1983 | } |
d741bf41 | 1984 | node = node->next; |
66ada2cc | 1985 | } |
03bac0df | 1986 | return NULL; |
3d7e3382 | 1987 | } |
03bac0df | 1988 | NOKPROBE_SYMBOL(__kretprobe_find_ret_addr); |
1da177e4 | 1989 | |
03bac0df MH |
1990 | /** |
1991 | * kretprobe_find_ret_addr -- Find correct return address modified by kretprobe | |
1992 | * @tsk: Target task | |
1993 | * @fp: A frame pointer | |
1994 | * @cur: a storage of the loop cursor llist_node pointer for next call | |
1995 | * | |
1996 | * Find the correct return address modified by a kretprobe on @tsk in unsigned | |
1997 | * long type. If it finds the return address, this returns that address value, | |
1998 | * or this returns 0. | |
1999 | * The @tsk must be 'current' or a task which is not running. @fp is a hint | |
2000 | * to get the currect return address - which is compared with the | |
2001 | * kretprobe_instance::fp field. The @cur is a loop cursor for searching the | |
2002 | * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the | |
2003 | * first call, but '@cur' itself must NOT NULL. | |
2004 | */ | |
2005 | unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, | |
2006 | struct llist_node **cur) | |
2007 | { | |
9efd24ec | 2008 | struct kretprobe_instance *ri; |
03bac0df MH |
2009 | kprobe_opcode_t *ret; |
2010 | ||
2011 | if (WARN_ON_ONCE(!cur)) | |
2012 | return 0; | |
66ada2cc | 2013 | |
03bac0df MH |
2014 | do { |
2015 | ret = __kretprobe_find_ret_addr(tsk, cur); | |
2016 | if (!ret) | |
2017 | break; | |
2018 | ri = container_of(*cur, struct kretprobe_instance, llist); | |
2019 | } while (ri->fp != fp); | |
2020 | ||
2021 | return (unsigned long)ret; | |
2022 | } | |
2023 | NOKPROBE_SYMBOL(kretprobe_find_ret_addr); | |
2024 | ||
bf094cff MH |
2025 | void __weak arch_kretprobe_fixup_return(struct pt_regs *regs, |
2026 | kprobe_opcode_t *correct_ret_addr) | |
2027 | { | |
2028 | /* | |
2029 | * Do nothing by default. Please fill this to update the fake return | |
2030 | * address on the stack with the correct one on each arch if possible. | |
2031 | */ | |
2032 | } | |
66ada2cc MH |
2033 | |
2034 | unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, | |
66ada2cc MH |
2035 | void *frame_pointer) |
2036 | { | |
d741bf41 | 2037 | struct kretprobe_instance *ri = NULL; |
03bac0df | 2038 | struct llist_node *first, *node = NULL; |
e1164787 | 2039 | kprobe_opcode_t *correct_ret_addr; |
d741bf41 | 2040 | struct kretprobe *rp; |
66ada2cc | 2041 | |
03bac0df MH |
2042 | /* Find correct address and all nodes for this frame. */ |
2043 | correct_ret_addr = __kretprobe_find_ret_addr(current, &node); | |
2044 | if (!correct_ret_addr) { | |
2045 | pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n"); | |
2046 | BUG_ON(1); | |
66ada2cc MH |
2047 | } |
2048 | ||
df91c5bc MH |
2049 | /* |
2050 | * Set the return address as the instruction pointer, because if the | |
2051 | * user handler calls stack_trace_save_regs() with this 'regs', | |
2052 | * the stack trace will start from the instruction pointer. | |
2053 | */ | |
2054 | instruction_pointer_set(regs, (unsigned long)correct_ret_addr); | |
66ada2cc | 2055 | |
03bac0df MH |
2056 | /* Run the user handler of the nodes. */ |
2057 | first = current->kretprobe_instances.first; | |
d741bf41 PZ |
2058 | while (first) { |
2059 | ri = container_of(first, struct kretprobe_instance, llist); | |
03bac0df MH |
2060 | |
2061 | if (WARN_ON_ONCE(ri->fp != frame_pointer)) | |
2062 | break; | |
66ada2cc | 2063 | |
d741bf41 PZ |
2064 | rp = get_kretprobe(ri); |
2065 | if (rp && rp->handler) { | |
66ada2cc MH |
2066 | struct kprobe *prev = kprobe_running(); |
2067 | ||
d741bf41 | 2068 | __this_cpu_write(current_kprobe, &rp->kp); |
66ada2cc | 2069 | ri->ret_addr = correct_ret_addr; |
d741bf41 | 2070 | rp->handler(ri, regs); |
66ada2cc MH |
2071 | __this_cpu_write(current_kprobe, prev); |
2072 | } | |
03bac0df MH |
2073 | if (first == node) |
2074 | break; | |
2075 | ||
2076 | first = first->next; | |
2077 | } | |
2078 | ||
bf094cff MH |
2079 | arch_kretprobe_fixup_return(regs, correct_ret_addr); |
2080 | ||
03bac0df MH |
2081 | /* Unlink all nodes for this frame. */ |
2082 | first = current->kretprobe_instances.first; | |
2083 | current->kretprobe_instances.first = node->next; | |
2084 | node->next = NULL; | |
2085 | ||
2086 | /* Recycle free instances. */ | |
2087 | while (first) { | |
2088 | ri = container_of(first, struct kretprobe_instance, llist); | |
2089 | first = first->next; | |
66ada2cc | 2090 | |
b3388178 | 2091 | recycle_rp_inst(ri); |
66ada2cc MH |
2092 | } |
2093 | ||
66ada2cc MH |
2094 | return (unsigned long)correct_ret_addr; |
2095 | } | |
2096 | NOKPROBE_SYMBOL(__kretprobe_trampoline_handler) | |
2097 | ||
e65cefe8 AB |
2098 | /* |
2099 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
2100 | * hits it will set up the return probe. | |
2101 | */ | |
820aede0 | 2102 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
e65cefe8 AB |
2103 | { |
2104 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
4bbd9345 | 2105 | struct kretprobe_holder *rph = rp->rph; |
ef53d9c5 | 2106 | struct kretprobe_instance *ri; |
e65cefe8 | 2107 | |
4bbd9345 | 2108 | ri = objpool_pop(&rph->pool); |
2109 | if (!ri) { | |
6e426e0f PZ |
2110 | rp->nmissed++; |
2111 | return 0; | |
2112 | } | |
4c4308cb | 2113 | |
6e426e0f | 2114 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
4bbd9345 | 2115 | objpool_push(ri, &rph->pool); |
6e426e0f | 2116 | return 0; |
ef53d9c5 | 2117 | } |
6e426e0f PZ |
2118 | |
2119 | arch_prepare_kretprobe(ri, regs); | |
2120 | ||
2121 | __llist_add(&ri->llist, ¤t->kretprobe_instances); | |
2122 | ||
e65cefe8 AB |
2123 | return 0; |
2124 | } | |
820aede0 | 2125 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
73f9b911 MH |
2126 | #else /* CONFIG_KRETPROBE_ON_RETHOOK */ |
2127 | /* | |
2128 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
2129 | * hits it will set up the return probe. | |
2130 | */ | |
2131 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) | |
2132 | { | |
2133 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
2134 | struct kretprobe_instance *ri; | |
2135 | struct rethook_node *rhn; | |
2136 | ||
2137 | rhn = rethook_try_get(rp->rh); | |
2138 | if (!rhn) { | |
2139 | rp->nmissed++; | |
2140 | return 0; | |
2141 | } | |
2142 | ||
2143 | ri = container_of(rhn, struct kretprobe_instance, node); | |
2144 | ||
2145 | if (rp->entry_handler && rp->entry_handler(ri, regs)) | |
2146 | rethook_recycle(rhn); | |
2147 | else | |
2148 | rethook_hook(rhn, regs, kprobe_ftrace(p)); | |
2149 | ||
2150 | return 0; | |
2151 | } | |
2152 | NOKPROBE_SYMBOL(pre_handler_kretprobe); | |
2153 | ||
2154 | static void kretprobe_rethook_handler(struct rethook_node *rh, void *data, | |
cb16330d | 2155 | unsigned long ret_addr, |
73f9b911 MH |
2156 | struct pt_regs *regs) |
2157 | { | |
2158 | struct kretprobe *rp = (struct kretprobe *)data; | |
2159 | struct kretprobe_instance *ri; | |
2160 | struct kprobe_ctlblk *kcb; | |
2161 | ||
2162 | /* The data must NOT be null. This means rethook data structure is broken. */ | |
1d661ed5 | 2163 | if (WARN_ON_ONCE(!data) || !rp->handler) |
73f9b911 MH |
2164 | return; |
2165 | ||
2166 | __this_cpu_write(current_kprobe, &rp->kp); | |
2167 | kcb = get_kprobe_ctlblk(); | |
2168 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
2169 | ||
2170 | ri = container_of(rh, struct kretprobe_instance, node); | |
2171 | rp->handler(ri, regs); | |
2172 | ||
2173 | __this_cpu_write(current_kprobe, NULL); | |
2174 | } | |
2175 | NOKPROBE_SYMBOL(kretprobe_rethook_handler); | |
2176 | ||
2177 | #endif /* !CONFIG_KRETPROBE_ON_RETHOOK */ | |
e65cefe8 | 2178 | |
97c753e6 MH |
2179 | /** |
2180 | * kprobe_on_func_entry() -- check whether given address is function entry | |
2181 | * @addr: Target address | |
2182 | * @sym: Target symbol name | |
2183 | * @offset: The offset from the symbol or the address | |
2184 | * | |
2185 | * This checks whether the given @addr+@offset or @sym+@offset is on the | |
2186 | * function entry address or not. | |
2187 | * This returns 0 if it is the function entry, or -EINVAL if it is not. | |
2188 | * And also it returns -ENOENT if it fails the symbol or address lookup. | |
2189 | * Caller must pass @addr or @sym (either one must be NULL), or this | |
2190 | * returns -EINVAL. | |
2191 | */ | |
2192 | int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) | |
1d585e70 | 2193 | { |
cc66bb91 PZ |
2194 | bool on_func_entry; |
2195 | kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset, &on_func_entry); | |
1d585e70 NR |
2196 | |
2197 | if (IS_ERR(kp_addr)) | |
97c753e6 | 2198 | return PTR_ERR(kp_addr); |
1d585e70 | 2199 | |
cc66bb91 | 2200 | if (!on_func_entry) |
97c753e6 MH |
2201 | return -EINVAL; |
2202 | ||
2203 | return 0; | |
1d585e70 NR |
2204 | } |
2205 | ||
55479f64 | 2206 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 | 2207 | { |
97c753e6 | 2208 | int ret; |
b94cce92 | 2209 | int i; |
b2a5cd69 | 2210 | void *addr; |
90ec5e89 | 2211 | |
97c753e6 MH |
2212 | ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset); |
2213 | if (ret) | |
2214 | return ret; | |
f438d914 | 2215 | |
223a76b2 | 2216 | /* If only 'rp->kp.addr' is specified, check reregistering kprobes */ |
33b1d146 | 2217 | if (rp->kp.addr && warn_kprobe_rereg(&rp->kp)) |
0188b878 WS |
2218 | return -EINVAL; |
2219 | ||
f438d914 | 2220 | if (kretprobe_blacklist_size) { |
b2a5cd69 | 2221 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
2222 | if (IS_ERR(addr)) |
2223 | return PTR_ERR(addr); | |
f438d914 MH |
2224 | |
2225 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
2226 | if (kretprobe_blacklist[i].addr == addr) | |
2227 | return -EINVAL; | |
2228 | } | |
2229 | } | |
b94cce92 | 2230 | |
6bbfa441 MH |
2231 | if (rp->data_size > KRETPROBE_MAX_DATA_SIZE) |
2232 | return -E2BIG; | |
2233 | ||
b94cce92 | 2234 | rp->kp.pre_handler = pre_handler_kretprobe; |
7522a842 | 2235 | rp->kp.post_handler = NULL; |
b94cce92 HN |
2236 | |
2237 | /* Pre-allocate memory for max kretprobe instances */ | |
3b7ddab8 | 2238 | if (rp->maxactive <= 0) |
c2ef6661 | 2239 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
3b7ddab8 | 2240 | |
73f9b911 | 2241 | #ifdef CONFIG_KRETPROBE_ON_RETHOOK |
4bbd9345 | 2242 | rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler, |
2243 | sizeof(struct kretprobe_instance) + | |
2244 | rp->data_size, rp->maxactive); | |
2245 | if (IS_ERR(rp->rh)) | |
2246 | return PTR_ERR(rp->rh); | |
73f9b911 | 2247 | |
73f9b911 MH |
2248 | rp->nmissed = 0; |
2249 | /* Establish function entry probe point */ | |
2250 | ret = register_kprobe(&rp->kp); | |
2251 | if (ret != 0) { | |
2252 | rethook_free(rp->rh); | |
2253 | rp->rh = NULL; | |
2254 | } | |
2255 | #else /* !CONFIG_KRETPROBE_ON_RETHOOK */ | |
d741bf41 PZ |
2256 | rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL); |
2257 | if (!rp->rph) | |
2258 | return -ENOMEM; | |
2259 | ||
4bbd9345 | 2260 | if (objpool_init(&rp->rph->pool, rp->maxactive, rp->data_size + |
2261 | sizeof(struct kretprobe_instance), GFP_KERNEL, | |
2262 | rp->rph, kretprobe_init_inst, kretprobe_fini_pool)) { | |
2263 | kfree(rp->rph); | |
2264 | rp->rph = NULL; | |
2265 | return -ENOMEM; | |
b94cce92 | 2266 | } |
d839a656 | 2267 | rcu_assign_pointer(rp->rph->rp, rp); |
b94cce92 HN |
2268 | rp->nmissed = 0; |
2269 | /* Establish function entry probe point */ | |
49ad2fd7 | 2270 | ret = register_kprobe(&rp->kp); |
4a296e07 | 2271 | if (ret != 0) |
b94cce92 | 2272 | free_rp_inst(rp); |
73f9b911 | 2273 | #endif |
b94cce92 HN |
2274 | return ret; |
2275 | } | |
99081ab5 | 2276 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2277 | |
55479f64 | 2278 | int register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2279 | { |
2280 | int ret = 0, i; | |
2281 | ||
2282 | if (num <= 0) | |
2283 | return -EINVAL; | |
2284 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 2285 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
2286 | if (ret < 0) { |
2287 | if (i > 0) | |
2288 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
2289 | break; |
2290 | } | |
2291 | } | |
2292 | return ret; | |
2293 | } | |
99081ab5 | 2294 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 2295 | |
55479f64 | 2296 | void unregister_kretprobe(struct kretprobe *rp) |
4a296e07 MH |
2297 | { |
2298 | unregister_kretprobes(&rp, 1); | |
2299 | } | |
99081ab5 | 2300 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 2301 | |
55479f64 | 2302 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2303 | { |
2304 | int i; | |
2305 | ||
2306 | if (num <= 0) | |
2307 | return; | |
2308 | mutex_lock(&kprobe_mutex); | |
d741bf41 | 2309 | for (i = 0; i < num; i++) { |
4a296e07 MH |
2310 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) |
2311 | rps[i]->kp.addr = NULL; | |
73f9b911 MH |
2312 | #ifdef CONFIG_KRETPROBE_ON_RETHOOK |
2313 | rethook_free(rps[i]->rh); | |
2314 | #else | |
d839a656 | 2315 | rcu_assign_pointer(rps[i]->rph->rp, NULL); |
73f9b911 | 2316 | #endif |
d741bf41 | 2317 | } |
4a296e07 MH |
2318 | mutex_unlock(&kprobe_mutex); |
2319 | ||
ae8b7ce7 | 2320 | synchronize_rcu(); |
4a296e07 MH |
2321 | for (i = 0; i < num; i++) { |
2322 | if (rps[i]->kp.addr) { | |
2323 | __unregister_kprobe_bottom(&rps[i]->kp); | |
73f9b911 | 2324 | #ifndef CONFIG_KRETPROBE_ON_RETHOOK |
d741bf41 | 2325 | free_rp_inst(rps[i]); |
73f9b911 | 2326 | #endif |
4a296e07 MH |
2327 | } |
2328 | } | |
2329 | } | |
99081ab5 | 2330 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 2331 | |
9edddaa2 | 2332 | #else /* CONFIG_KRETPROBES */ |
55479f64 | 2333 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 | 2334 | { |
223a76b2 | 2335 | return -EOPNOTSUPP; |
b94cce92 | 2336 | } |
99081ab5 | 2337 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2338 | |
55479f64 | 2339 | int register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 2340 | { |
223a76b2 | 2341 | return -EOPNOTSUPP; |
346fd59b | 2342 | } |
99081ab5 MH |
2343 | EXPORT_SYMBOL_GPL(register_kretprobes); |
2344 | ||
55479f64 | 2345 | void unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 2346 | { |
4a296e07 | 2347 | } |
99081ab5 | 2348 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 2349 | |
55479f64 | 2350 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2351 | { |
2352 | } | |
99081ab5 | 2353 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 2354 | |
820aede0 | 2355 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
4a296e07 MH |
2356 | { |
2357 | return 0; | |
b94cce92 | 2358 | } |
820aede0 | 2359 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
b94cce92 | 2360 | |
4a296e07 MH |
2361 | #endif /* CONFIG_KRETPROBES */ |
2362 | ||
e8386a0c | 2363 | /* Set the kprobe gone and remove its instruction buffer. */ |
55479f64 | 2364 | static void kill_kprobe(struct kprobe *p) |
e8386a0c MH |
2365 | { |
2366 | struct kprobe *kp; | |
de5bd88d | 2367 | |
7e6a71d8 MH |
2368 | lockdep_assert_held(&kprobe_mutex); |
2369 | ||
0c76ef3f LH |
2370 | /* |
2371 | * The module is going away. We should disarm the kprobe which | |
2372 | * is using ftrace, because ftrace framework is still available at | |
2373 | * 'MODULE_STATE_GOING' notification. | |
2374 | */ | |
2375 | if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed) | |
2376 | disarm_kprobe_ftrace(p); | |
2377 | ||
e8386a0c | 2378 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 2379 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
2380 | /* |
2381 | * If this is an aggr_kprobe, we have to list all the | |
2382 | * chained probes and mark them GONE. | |
2383 | */ | |
7e6a71d8 | 2384 | list_for_each_entry(kp, &p->list, list) |
e8386a0c MH |
2385 | kp->flags |= KPROBE_FLAG_GONE; |
2386 | p->post_handler = NULL; | |
afd66255 | 2387 | kill_optimized_kprobe(p); |
e8386a0c MH |
2388 | } |
2389 | /* | |
2390 | * Here, we can remove insn_slot safely, because no thread calls | |
2391 | * the original probed function (which will be freed soon) any more. | |
2392 | */ | |
2393 | arch_remove_kprobe(p); | |
2394 | } | |
2395 | ||
c0614829 | 2396 | /* Disable one kprobe */ |
55479f64 | 2397 | int disable_kprobe(struct kprobe *kp) |
c0614829 MH |
2398 | { |
2399 | int ret = 0; | |
297f9233 | 2400 | struct kprobe *p; |
c0614829 MH |
2401 | |
2402 | mutex_lock(&kprobe_mutex); | |
2403 | ||
6f0f1dd7 | 2404 | /* Disable this kprobe */ |
297f9233 JY |
2405 | p = __disable_kprobe(kp); |
2406 | if (IS_ERR(p)) | |
2407 | ret = PTR_ERR(p); | |
c0614829 | 2408 | |
c0614829 MH |
2409 | mutex_unlock(&kprobe_mutex); |
2410 | return ret; | |
2411 | } | |
2412 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
2413 | ||
2414 | /* Enable one kprobe */ | |
55479f64 | 2415 | int enable_kprobe(struct kprobe *kp) |
c0614829 MH |
2416 | { |
2417 | int ret = 0; | |
2418 | struct kprobe *p; | |
2419 | ||
2420 | mutex_lock(&kprobe_mutex); | |
2421 | ||
2422 | /* Check whether specified probe is valid. */ | |
2423 | p = __get_valid_kprobe(kp); | |
2424 | if (unlikely(p == NULL)) { | |
2425 | ret = -EINVAL; | |
2426 | goto out; | |
2427 | } | |
2428 | ||
2429 | if (kprobe_gone(kp)) { | |
2430 | /* This kprobe has gone, we couldn't enable it. */ | |
2431 | ret = -EINVAL; | |
2432 | goto out; | |
2433 | } | |
2434 | ||
2435 | if (p != kp) | |
2436 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
2437 | ||
2438 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
2439 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
12310e34 | 2440 | ret = arm_kprobe(p); |
4a6f316d | 2441 | if (ret) { |
12310e34 | 2442 | p->flags |= KPROBE_FLAG_DISABLED; |
4a6f316d LQ |
2443 | if (p != kp) |
2444 | kp->flags |= KPROBE_FLAG_DISABLED; | |
2445 | } | |
c0614829 MH |
2446 | } |
2447 | out: | |
2448 | mutex_unlock(&kprobe_mutex); | |
2449 | return ret; | |
2450 | } | |
2451 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
2452 | ||
4458515b | 2453 | /* Caller must NOT call this in usual path. This is only for critical case */ |
820aede0 | 2454 | void dump_kprobe(struct kprobe *kp) |
24851d24 | 2455 | { |
9c89bb8e | 2456 | pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n", |
4458515b | 2457 | kp->symbol_name, kp->offset, kp->addr); |
24851d24 | 2458 | } |
820aede0 | 2459 | NOKPROBE_SYMBOL(dump_kprobe); |
24851d24 | 2460 | |
fb1a59fa MH |
2461 | int kprobe_add_ksym_blacklist(unsigned long entry) |
2462 | { | |
2463 | struct kprobe_blacklist_entry *ent; | |
2464 | unsigned long offset = 0, size = 0; | |
2465 | ||
2466 | if (!kernel_text_address(entry) || | |
2467 | !kallsyms_lookup_size_offset(entry, &size, &offset)) | |
2468 | return -EINVAL; | |
2469 | ||
2470 | ent = kmalloc(sizeof(*ent), GFP_KERNEL); | |
2471 | if (!ent) | |
2472 | return -ENOMEM; | |
2473 | ent->start_addr = entry; | |
2474 | ent->end_addr = entry + size; | |
2475 | INIT_LIST_HEAD(&ent->list); | |
2476 | list_add_tail(&ent->list, &kprobe_blacklist); | |
2477 | ||
2478 | return (int)size; | |
2479 | } | |
2480 | ||
2481 | /* Add all symbols in given area into kprobe blacklist */ | |
2482 | int kprobe_add_area_blacklist(unsigned long start, unsigned long end) | |
2483 | { | |
2484 | unsigned long entry; | |
2485 | int ret = 0; | |
2486 | ||
2487 | for (entry = start; entry < end; entry += ret) { | |
2488 | ret = kprobe_add_ksym_blacklist(entry); | |
2489 | if (ret < 0) | |
2490 | return ret; | |
2491 | if (ret == 0) /* In case of alias symbol */ | |
2492 | ret = 1; | |
2493 | } | |
2494 | return 0; | |
2495 | } | |
2496 | ||
d002b8bc AH |
2497 | int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, |
2498 | char *type, char *sym) | |
2499 | { | |
2500 | return -ERANGE; | |
2501 | } | |
2502 | ||
2503 | int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, | |
2504 | char *sym) | |
2505 | { | |
2506 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT | |
2507 | if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym)) | |
2508 | return 0; | |
2509 | #ifdef CONFIG_OPTPROBES | |
2510 | if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym)) | |
2511 | return 0; | |
2512 | #endif | |
2513 | #endif | |
2514 | if (!arch_kprobe_get_kallsym(&symnum, value, type, sym)) | |
2515 | return 0; | |
2516 | return -ERANGE; | |
2517 | } | |
2518 | ||
fb1a59fa MH |
2519 | int __init __weak arch_populate_kprobe_blacklist(void) |
2520 | { | |
2521 | return 0; | |
2522 | } | |
2523 | ||
376e2424 MH |
2524 | /* |
2525 | * Lookup and populate the kprobe_blacklist. | |
2526 | * | |
2527 | * Unlike the kretprobe blacklist, we'll need to determine | |
2528 | * the range of addresses that belong to the said functions, | |
2529 | * since a kprobe need not necessarily be at the beginning | |
2530 | * of a function. | |
2531 | */ | |
2532 | static int __init populate_kprobe_blacklist(unsigned long *start, | |
2533 | unsigned long *end) | |
2534 | { | |
fb1a59fa | 2535 | unsigned long entry; |
376e2424 | 2536 | unsigned long *iter; |
fb1a59fa | 2537 | int ret; |
376e2424 MH |
2538 | |
2539 | for (iter = start; iter < end; iter++) { | |
f2ec8d9a | 2540 | entry = (unsigned long)dereference_symbol_descriptor((void *)*iter); |
fb1a59fa MH |
2541 | ret = kprobe_add_ksym_blacklist(entry); |
2542 | if (ret == -EINVAL) | |
376e2424 | 2543 | continue; |
fb1a59fa MH |
2544 | if (ret < 0) |
2545 | return ret; | |
376e2424 | 2546 | } |
fb1a59fa | 2547 | |
223a76b2 | 2548 | /* Symbols in '__kprobes_text' are blacklisted */ |
fb1a59fa MH |
2549 | ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, |
2550 | (unsigned long)__kprobes_text_end); | |
66e9b071 TG |
2551 | if (ret) |
2552 | return ret; | |
2553 | ||
223a76b2 | 2554 | /* Symbols in 'noinstr' section are blacklisted */ |
66e9b071 TG |
2555 | ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start, |
2556 | (unsigned long)__noinstr_text_end); | |
fb1a59fa MH |
2557 | |
2558 | return ret ? : arch_populate_kprobe_blacklist(); | |
376e2424 MH |
2559 | } |
2560 | ||
7582b7be MRI |
2561 | #ifdef CONFIG_MODULES |
2562 | /* Remove all symbols in given area from kprobe blacklist */ | |
2563 | static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) | |
2564 | { | |
2565 | struct kprobe_blacklist_entry *ent, *n; | |
2566 | ||
2567 | list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { | |
2568 | if (ent->start_addr < start || ent->start_addr >= end) | |
2569 | continue; | |
2570 | list_del(&ent->list); | |
2571 | kfree(ent); | |
2572 | } | |
2573 | } | |
2574 | ||
2575 | static void kprobe_remove_ksym_blacklist(unsigned long entry) | |
2576 | { | |
2577 | kprobe_remove_area_blacklist(entry, entry + 1); | |
2578 | } | |
2579 | ||
1e6769b0 MH |
2580 | static void add_module_kprobe_blacklist(struct module *mod) |
2581 | { | |
2582 | unsigned long start, end; | |
16db6264 MH |
2583 | int i; |
2584 | ||
2585 | if (mod->kprobe_blacklist) { | |
2586 | for (i = 0; i < mod->num_kprobe_blacklist; i++) | |
2587 | kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]); | |
2588 | } | |
1e6769b0 MH |
2589 | |
2590 | start = (unsigned long)mod->kprobes_text_start; | |
2591 | if (start) { | |
2592 | end = start + mod->kprobes_text_size; | |
2593 | kprobe_add_area_blacklist(start, end); | |
2594 | } | |
66e9b071 TG |
2595 | |
2596 | start = (unsigned long)mod->noinstr_text_start; | |
2597 | if (start) { | |
2598 | end = start + mod->noinstr_text_size; | |
2599 | kprobe_add_area_blacklist(start, end); | |
2600 | } | |
1e6769b0 MH |
2601 | } |
2602 | ||
2603 | static void remove_module_kprobe_blacklist(struct module *mod) | |
2604 | { | |
2605 | unsigned long start, end; | |
16db6264 MH |
2606 | int i; |
2607 | ||
2608 | if (mod->kprobe_blacklist) { | |
2609 | for (i = 0; i < mod->num_kprobe_blacklist; i++) | |
2610 | kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]); | |
2611 | } | |
1e6769b0 MH |
2612 | |
2613 | start = (unsigned long)mod->kprobes_text_start; | |
2614 | if (start) { | |
2615 | end = start + mod->kprobes_text_size; | |
2616 | kprobe_remove_area_blacklist(start, end); | |
2617 | } | |
66e9b071 TG |
2618 | |
2619 | start = (unsigned long)mod->noinstr_text_start; | |
2620 | if (start) { | |
2621 | end = start + mod->noinstr_text_size; | |
2622 | kprobe_remove_area_blacklist(start, end); | |
2623 | } | |
1e6769b0 MH |
2624 | } |
2625 | ||
e8386a0c | 2626 | /* Module notifier call back, checking kprobes on the module */ |
55479f64 MH |
2627 | static int kprobes_module_callback(struct notifier_block *nb, |
2628 | unsigned long val, void *data) | |
e8386a0c MH |
2629 | { |
2630 | struct module *mod = data; | |
2631 | struct hlist_head *head; | |
e8386a0c MH |
2632 | struct kprobe *p; |
2633 | unsigned int i; | |
f24659d9 | 2634 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2635 | |
1e6769b0 MH |
2636 | if (val == MODULE_STATE_COMING) { |
2637 | mutex_lock(&kprobe_mutex); | |
2638 | add_module_kprobe_blacklist(mod); | |
2639 | mutex_unlock(&kprobe_mutex); | |
2640 | } | |
f24659d9 | 2641 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2642 | return NOTIFY_DONE; |
2643 | ||
2644 | /* | |
223a76b2 MH |
2645 | * When 'MODULE_STATE_GOING' was notified, both of module '.text' and |
2646 | * '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was | |
2647 | * notified, only '.init.text' section would be freed. We need to | |
f24659d9 | 2648 | * disable kprobes which have been inserted in the sections. |
e8386a0c MH |
2649 | */ |
2650 | mutex_lock(&kprobe_mutex); | |
2651 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2652 | head = &kprobe_table[i]; | |
7e6a71d8 | 2653 | hlist_for_each_entry(p, head, hlist) |
f24659d9 MH |
2654 | if (within_module_init((unsigned long)p->addr, mod) || |
2655 | (checkcore && | |
2656 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2657 | /* |
2658 | * The vaddr this probe is installed will soon | |
2659 | * be vfreed buy not synced to disk. Hence, | |
2660 | * disarming the breakpoint isn't needed. | |
545a0281 SRV |
2661 | * |
2662 | * Note, this will also move any optimized probes | |
2663 | * that are pending to be removed from their | |
223a76b2 | 2664 | * corresponding lists to the 'freeing_list' and |
545a0281 | 2665 | * will not be touched by the delayed |
223a76b2 | 2666 | * kprobe_optimizer() work handler. |
e8386a0c MH |
2667 | */ |
2668 | kill_kprobe(p); | |
2669 | } | |
2670 | } | |
1e6769b0 MH |
2671 | if (val == MODULE_STATE_GOING) |
2672 | remove_module_kprobe_blacklist(mod); | |
e8386a0c MH |
2673 | mutex_unlock(&kprobe_mutex); |
2674 | return NOTIFY_DONE; | |
2675 | } | |
2676 | ||
2677 | static struct notifier_block kprobe_module_nb = { | |
2678 | .notifier_call = kprobes_module_callback, | |
2679 | .priority = 0 | |
2680 | }; | |
2681 | ||
7582b7be MRI |
2682 | static int kprobe_register_module_notifier(void) |
2683 | { | |
2684 | return register_module_notifier(&kprobe_module_nb); | |
2685 | } | |
2686 | #else | |
2687 | static int kprobe_register_module_notifier(void) | |
2688 | { | |
2689 | return 0; | |
2690 | } | |
2691 | #endif /* CONFIG_MODULES */ | |
2692 | ||
82d083ab MH |
2693 | void kprobe_free_init_mem(void) |
2694 | { | |
2695 | void *start = (void *)(&__init_begin); | |
2696 | void *end = (void *)(&__init_end); | |
2697 | struct hlist_head *head; | |
2698 | struct kprobe *p; | |
2699 | int i; | |
2700 | ||
2701 | mutex_lock(&kprobe_mutex); | |
2702 | ||
223a76b2 | 2703 | /* Kill all kprobes on initmem because the target code has been freed. */ |
82d083ab MH |
2704 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2705 | head = &kprobe_table[i]; | |
2706 | hlist_for_each_entry(p, head, hlist) { | |
2707 | if (start <= (void *)p->addr && (void *)p->addr < end) | |
2708 | kill_kprobe(p); | |
2709 | } | |
2710 | } | |
2711 | ||
2712 | mutex_unlock(&kprobe_mutex); | |
2713 | } | |
2714 | ||
1da177e4 LT |
2715 | static int __init init_kprobes(void) |
2716 | { | |
ed9492df | 2717 | int i, err; |
1da177e4 LT |
2718 | |
2719 | /* FIXME allocate the probe table, currently defined statically */ | |
2720 | /* initialize all list heads */ | |
d741bf41 | 2721 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) |
1da177e4 LT |
2722 | INIT_HLIST_HEAD(&kprobe_table[i]); |
2723 | ||
376e2424 MH |
2724 | err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
2725 | __stop_kprobe_blacklist); | |
223a76b2 | 2726 | if (err) |
9c89bb8e | 2727 | pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err); |
3d8d996e | 2728 | |
f438d914 MH |
2729 | if (kretprobe_blacklist_size) { |
2730 | /* lookup the function address from its name */ | |
2731 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
49e0b465 | 2732 | kretprobe_blacklist[i].addr = |
290e3070 | 2733 | kprobe_lookup_name(kretprobe_blacklist[i].name, 0); |
f438d914 | 2734 | if (!kretprobe_blacklist[i].addr) |
9c89bb8e | 2735 | pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n", |
f438d914 MH |
2736 | kretprobe_blacklist[i].name); |
2737 | } | |
2738 | } | |
2739 | ||
e579abeb MH |
2740 | /* By default, kprobes are armed */ |
2741 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2742 | |
c85c9a2c | 2743 | #if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
223a76b2 | 2744 | /* Init 'kprobe_optinsn_slots' for allocation */ |
c85c9a2c MH |
2745 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; |
2746 | #endif | |
2747 | ||
6772926b | 2748 | err = arch_init_kprobes(); |
802eae7c RL |
2749 | if (!err) |
2750 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c | 2751 | if (!err) |
7582b7be | 2752 | err = kprobe_register_module_notifier(); |
e8386a0c | 2753 | |
ef53d9c5 | 2754 | kprobes_initialized = (err == 0); |
a737a3c6 | 2755 | kprobe_sysctls_init(); |
1da177e4 LT |
2756 | return err; |
2757 | } | |
36dadef2 | 2758 | early_initcall(init_kprobes); |
1da177e4 | 2759 | |
c85c9a2c MH |
2760 | #if defined(CONFIG_OPTPROBES) |
2761 | static int __init init_optprobes(void) | |
2762 | { | |
2763 | /* | |
2764 | * Enable kprobe optimization - this kicks the optimizer which | |
2765 | * depends on synchronize_rcu_tasks() and ksoftirqd, that is | |
2766 | * not spawned in early initcall. So delay the optimization. | |
2767 | */ | |
2768 | optimize_all_kprobes(); | |
2769 | ||
2770 | return 0; | |
2771 | } | |
2772 | subsys_initcall(init_optprobes); | |
2773 | #endif | |
2774 | ||
346fd59b | 2775 | #ifdef CONFIG_DEBUG_FS |
55479f64 | 2776 | static void report_probe(struct seq_file *pi, struct kprobe *p, |
afd66255 | 2777 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2778 | { |
2779 | char *kprobe_type; | |
81365a94 | 2780 | void *addr = p->addr; |
346fd59b SD |
2781 | |
2782 | if (p->pre_handler == pre_handler_kretprobe) | |
2783 | kprobe_type = "r"; | |
346fd59b SD |
2784 | else |
2785 | kprobe_type = "k"; | |
afd66255 | 2786 | |
60f7bb66 | 2787 | if (!kallsyms_show_value(pi->file->f_cred)) |
81365a94 MH |
2788 | addr = NULL; |
2789 | ||
346fd59b | 2790 | if (sym) |
81365a94 MH |
2791 | seq_printf(pi, "%px %s %s+0x%x %s ", |
2792 | addr, kprobe_type, sym, offset, | |
afd66255 | 2793 | (modname ? modname : " ")); |
81365a94 MH |
2794 | else /* try to use %pS */ |
2795 | seq_printf(pi, "%px %s %pS ", | |
2796 | addr, kprobe_type, p->addr); | |
afd66255 MH |
2797 | |
2798 | if (!pp) | |
2799 | pp = p; | |
ae6aa16f | 2800 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2801 | (kprobe_gone(p) ? "[GONE]" : ""), |
2802 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2803 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2804 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2805 | } |
2806 | ||
55479f64 | 2807 | static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
346fd59b SD |
2808 | { |
2809 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2810 | } | |
2811 | ||
55479f64 | 2812 | static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
346fd59b SD |
2813 | { |
2814 | (*pos)++; | |
2815 | if (*pos >= KPROBE_TABLE_SIZE) | |
2816 | return NULL; | |
2817 | return pos; | |
2818 | } | |
2819 | ||
55479f64 | 2820 | static void kprobe_seq_stop(struct seq_file *f, void *v) |
346fd59b SD |
2821 | { |
2822 | /* Nothing to do */ | |
2823 | } | |
2824 | ||
55479f64 | 2825 | static int show_kprobe_addr(struct seq_file *pi, void *v) |
346fd59b SD |
2826 | { |
2827 | struct hlist_head *head; | |
346fd59b | 2828 | struct kprobe *p, *kp; |
9efd24ec | 2829 | const char *sym; |
346fd59b | 2830 | unsigned int i = *(loff_t *) v; |
ffb45122 | 2831 | unsigned long offset = 0; |
ab767865 | 2832 | char *modname, namebuf[KSYM_NAME_LEN]; |
346fd59b SD |
2833 | |
2834 | head = &kprobe_table[i]; | |
2835 | preempt_disable(); | |
b67bfe0d | 2836 | hlist_for_each_entry_rcu(p, head, hlist) { |
ffb45122 | 2837 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2838 | &offset, &modname, namebuf); |
afd66255 | 2839 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2840 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2841 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2842 | } else |
afd66255 | 2843 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2844 | } |
2845 | preempt_enable(); | |
2846 | return 0; | |
2847 | } | |
2848 | ||
eac2cece | 2849 | static const struct seq_operations kprobes_sops = { |
346fd59b SD |
2850 | .start = kprobe_seq_start, |
2851 | .next = kprobe_seq_next, | |
2852 | .stop = kprobe_seq_stop, | |
2853 | .show = show_kprobe_addr | |
2854 | }; | |
2855 | ||
eac2cece | 2856 | DEFINE_SEQ_ATTRIBUTE(kprobes); |
346fd59b | 2857 | |
63724740 MH |
2858 | /* kprobes/blacklist -- shows which functions can not be probed */ |
2859 | static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) | |
2860 | { | |
4fdd8887 | 2861 | mutex_lock(&kprobe_mutex); |
63724740 MH |
2862 | return seq_list_start(&kprobe_blacklist, *pos); |
2863 | } | |
2864 | ||
2865 | static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
2866 | { | |
2867 | return seq_list_next(v, &kprobe_blacklist, pos); | |
2868 | } | |
2869 | ||
2870 | static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) | |
2871 | { | |
2872 | struct kprobe_blacklist_entry *ent = | |
2873 | list_entry(v, struct kprobe_blacklist_entry, list); | |
2874 | ||
ffb9bd68 | 2875 | /* |
223a76b2 | 2876 | * If '/proc/kallsyms' is not showing kernel address, we won't |
ffb9bd68 MH |
2877 | * show them here either. |
2878 | */ | |
60f7bb66 | 2879 | if (!kallsyms_show_value(m->file->f_cred)) |
ffb9bd68 MH |
2880 | seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL, |
2881 | (void *)ent->start_addr); | |
2882 | else | |
2883 | seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr, | |
2884 | (void *)ent->end_addr, (void *)ent->start_addr); | |
63724740 MH |
2885 | return 0; |
2886 | } | |
2887 | ||
4fdd8887 MH |
2888 | static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v) |
2889 | { | |
2890 | mutex_unlock(&kprobe_mutex); | |
2891 | } | |
2892 | ||
eac2cece | 2893 | static const struct seq_operations kprobe_blacklist_sops = { |
63724740 MH |
2894 | .start = kprobe_blacklist_seq_start, |
2895 | .next = kprobe_blacklist_seq_next, | |
4fdd8887 | 2896 | .stop = kprobe_blacklist_seq_stop, |
63724740 MH |
2897 | .show = kprobe_blacklist_seq_show, |
2898 | }; | |
eac2cece | 2899 | DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist); |
63724740 | 2900 | |
12310e34 | 2901 | static int arm_all_kprobes(void) |
bf8f6e5b AM |
2902 | { |
2903 | struct hlist_head *head; | |
bf8f6e5b | 2904 | struct kprobe *p; |
12310e34 JY |
2905 | unsigned int i, total = 0, errors = 0; |
2906 | int err, ret = 0; | |
bf8f6e5b AM |
2907 | |
2908 | mutex_lock(&kprobe_mutex); | |
2909 | ||
e579abeb MH |
2910 | /* If kprobes are armed, just return */ |
2911 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2912 | goto already_enabled; |
2913 | ||
977ad481 WN |
2914 | /* |
2915 | * optimize_kprobe() called by arm_kprobe() checks | |
2916 | * kprobes_all_disarmed, so set kprobes_all_disarmed before | |
2917 | * arm_kprobe. | |
2918 | */ | |
2919 | kprobes_all_disarmed = false; | |
afd66255 | 2920 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2921 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2922 | head = &kprobe_table[i]; | |
12310e34 | 2923 | /* Arm all kprobes on a best-effort basis */ |
7e6a71d8 | 2924 | hlist_for_each_entry(p, head, hlist) { |
12310e34 JY |
2925 | if (!kprobe_disabled(p)) { |
2926 | err = arm_kprobe(p); | |
2927 | if (err) { | |
2928 | errors++; | |
2929 | ret = err; | |
2930 | } | |
2931 | total++; | |
2932 | } | |
2933 | } | |
bf8f6e5b AM |
2934 | } |
2935 | ||
12310e34 | 2936 | if (errors) |
9c89bb8e | 2937 | 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 |
2938 | errors, total); |
2939 | else | |
2940 | pr_info("Kprobes globally enabled\n"); | |
bf8f6e5b AM |
2941 | |
2942 | already_enabled: | |
2943 | mutex_unlock(&kprobe_mutex); | |
12310e34 | 2944 | return ret; |
bf8f6e5b AM |
2945 | } |
2946 | ||
297f9233 | 2947 | static int disarm_all_kprobes(void) |
bf8f6e5b AM |
2948 | { |
2949 | struct hlist_head *head; | |
bf8f6e5b | 2950 | struct kprobe *p; |
297f9233 JY |
2951 | unsigned int i, total = 0, errors = 0; |
2952 | int err, ret = 0; | |
bf8f6e5b AM |
2953 | |
2954 | mutex_lock(&kprobe_mutex); | |
2955 | ||
e579abeb | 2956 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2957 | if (kprobes_all_disarmed) { |
2958 | mutex_unlock(&kprobe_mutex); | |
297f9233 | 2959 | return 0; |
6274de49 | 2960 | } |
bf8f6e5b | 2961 | |
e579abeb | 2962 | kprobes_all_disarmed = true; |
afd66255 | 2963 | |
bf8f6e5b AM |
2964 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2965 | head = &kprobe_table[i]; | |
297f9233 | 2966 | /* Disarm all kprobes on a best-effort basis */ |
7e6a71d8 | 2967 | hlist_for_each_entry(p, head, hlist) { |
297f9233 JY |
2968 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) { |
2969 | err = disarm_kprobe(p, false); | |
2970 | if (err) { | |
2971 | errors++; | |
2972 | ret = err; | |
2973 | } | |
2974 | total++; | |
2975 | } | |
bf8f6e5b AM |
2976 | } |
2977 | } | |
297f9233 JY |
2978 | |
2979 | if (errors) | |
9c89bb8e | 2980 | 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 |
2981 | errors, total); |
2982 | else | |
2983 | pr_info("Kprobes globally disabled\n"); | |
2984 | ||
bf8f6e5b | 2985 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2986 | |
6274de49 MH |
2987 | /* Wait for disarming all kprobes by optimizer */ |
2988 | wait_for_kprobe_optimizer(); | |
297f9233 JY |
2989 | |
2990 | return ret; | |
bf8f6e5b AM |
2991 | } |
2992 | ||
2993 | /* | |
2994 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2995 | * when the bool state is switched. We can reuse that facility when | |
2996 | * available | |
2997 | */ | |
2998 | static ssize_t read_enabled_file_bool(struct file *file, | |
2999 | char __user *user_buf, size_t count, loff_t *ppos) | |
3000 | { | |
3001 | char buf[3]; | |
3002 | ||
e579abeb | 3003 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
3004 | buf[0] = '1'; |
3005 | else | |
3006 | buf[0] = '0'; | |
3007 | buf[1] = '\n'; | |
3008 | buf[2] = 0x00; | |
3009 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
3010 | } | |
3011 | ||
3012 | static ssize_t write_enabled_file_bool(struct file *file, | |
3013 | const char __user *user_buf, size_t count, loff_t *ppos) | |
3014 | { | |
5d6de7d7 PA |
3015 | bool enable; |
3016 | int ret; | |
bf8f6e5b | 3017 | |
5d6de7d7 PA |
3018 | ret = kstrtobool_from_user(user_buf, count, &enable); |
3019 | if (ret) | |
3020 | return ret; | |
bf8f6e5b | 3021 | |
5d6de7d7 | 3022 | ret = enable ? arm_all_kprobes() : disarm_all_kprobes(); |
12310e34 JY |
3023 | if (ret) |
3024 | return ret; | |
3025 | ||
bf8f6e5b AM |
3026 | return count; |
3027 | } | |
3028 | ||
828c0950 | 3029 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
3030 | .read = read_enabled_file_bool, |
3031 | .write = write_enabled_file_bool, | |
6038f373 | 3032 | .llseek = default_llseek, |
bf8f6e5b AM |
3033 | }; |
3034 | ||
55479f64 | 3035 | static int __init debugfs_kprobe_init(void) |
346fd59b | 3036 | { |
8c0fd1fa | 3037 | struct dentry *dir; |
346fd59b SD |
3038 | |
3039 | dir = debugfs_create_dir("kprobes", NULL); | |
346fd59b | 3040 | |
eac2cece | 3041 | debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops); |
346fd59b | 3042 | |
8f7262cd | 3043 | debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp); |
63724740 | 3044 | |
8c0fd1fa | 3045 | debugfs_create_file("blacklist", 0400, dir, NULL, |
eac2cece | 3046 | &kprobe_blacklist_fops); |
bf8f6e5b | 3047 | |
346fd59b SD |
3048 | return 0; |
3049 | } | |
3050 | ||
3051 | late_initcall(debugfs_kprobe_init); | |
3052 | #endif /* CONFIG_DEBUG_FS */ |