Commit | Line | Data |
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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Kernel Probes (KProbes) | |
4 | * kernel/kprobes.c | |
5 | * | |
1da177e4 LT |
6 | * Copyright (C) IBM Corporation, 2002, 2004 |
7 | * | |
8 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel | |
9 | * Probes initial implementation (includes suggestions from | |
10 | * Rusty Russell). | |
11 | * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with | |
12 | * hlists and exceptions notifier as suggested by Andi Kleen. | |
13 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes | |
14 | * interface to access function arguments. | |
15 | * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes | |
16 | * exceptions notifier to be first on the priority list. | |
b94cce92 HN |
17 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
18 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi | |
19 | * <prasanna@in.ibm.com> added function-return probes. | |
1da177e4 LT |
20 | */ |
21 | #include <linux/kprobes.h> | |
1da177e4 LT |
22 | #include <linux/hash.h> |
23 | #include <linux/init.h> | |
4e57b681 | 24 | #include <linux/slab.h> |
e3869792 | 25 | #include <linux/stddef.h> |
9984de1a | 26 | #include <linux/export.h> |
9ec4b1f3 | 27 | #include <linux/moduleloader.h> |
3a872d89 | 28 | #include <linux/kallsyms.h> |
b4c6c34a | 29 | #include <linux/freezer.h> |
346fd59b SD |
30 | #include <linux/seq_file.h> |
31 | #include <linux/debugfs.h> | |
b2be84df | 32 | #include <linux/sysctl.h> |
1eeb66a1 | 33 | #include <linux/kdebug.h> |
4460fdad | 34 | #include <linux/memory.h> |
4554dbcb | 35 | #include <linux/ftrace.h> |
afd66255 | 36 | #include <linux/cpu.h> |
bf5438fc | 37 | #include <linux/jump_label.h> |
69e49088 | 38 | #include <linux/perf_event.h> |
bf8f6e5b | 39 | |
bfd45be0 | 40 | #include <asm/sections.h> |
1da177e4 LT |
41 | #include <asm/cacheflush.h> |
42 | #include <asm/errno.h> | |
7c0f6ba6 | 43 | #include <linux/uaccess.h> |
1da177e4 LT |
44 | |
45 | #define KPROBE_HASH_BITS 6 | |
46 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
47 | ||
3a872d89 | 48 | |
ef53d9c5 | 49 | static int kprobes_initialized; |
7e6a71d8 MH |
50 | /* kprobe_table can be accessed by |
51 | * - Normal hlist traversal and RCU add/del under kprobe_mutex is held. | |
52 | * Or | |
53 | * - RCU hlist traversal under disabling preempt (breakpoint handlers) | |
54 | */ | |
1da177e4 | 55 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 56 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 57 | |
bf8f6e5b | 58 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 59 | static bool kprobes_all_disarmed; |
bf8f6e5b | 60 | |
43948f50 MH |
61 | /* This protects kprobe_table and optimizing_list */ |
62 | static DEFINE_MUTEX(kprobe_mutex); | |
e6584523 | 63 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 64 | static struct { |
ec484608 | 65 | raw_spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
66 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
67 | ||
290e3070 NR |
68 | kprobe_opcode_t * __weak kprobe_lookup_name(const char *name, |
69 | unsigned int __unused) | |
49e0b465 NR |
70 | { |
71 | return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); | |
72 | } | |
73 | ||
ec484608 | 74 | static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
ef53d9c5 S |
75 | { |
76 | return &(kretprobe_table_locks[hash].lock); | |
77 | } | |
1da177e4 | 78 | |
376e2424 MH |
79 | /* Blacklist -- list of struct kprobe_blacklist_entry */ |
80 | static LIST_HEAD(kprobe_blacklist); | |
3d8d996e | 81 | |
2d14e39d | 82 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
83 | /* |
84 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
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 HC |
114 | { |
115 | return module_alloc(PAGE_SIZE); | |
116 | } | |
117 | ||
c93f5cf5 | 118 | void __weak free_insn_page(void *page) |
af96397d | 119 | { |
be1f221c | 120 | module_memfree(page); |
af96397d HC |
121 | } |
122 | ||
c802d64a HC |
123 | struct kprobe_insn_cache kprobe_insn_slots = { |
124 | .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), | |
af96397d HC |
125 | .alloc = alloc_insn_page, |
126 | .free = free_insn_page, | |
d002b8bc | 127 | .sym = KPROBE_INSN_PAGE_SYM, |
4610ee1d MH |
128 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
129 | .insn_size = MAX_INSN_SIZE, | |
130 | .nr_garbage = 0, | |
131 | }; | |
55479f64 | 132 | static int collect_garbage_slots(struct kprobe_insn_cache *c); |
b4c6c34a | 133 | |
9ec4b1f3 | 134 | /** |
12941560 | 135 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
136 | * We allocate an executable page if there's no room on existing ones. |
137 | */ | |
55479f64 | 138 | kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
139 | { |
140 | struct kprobe_insn_page *kip; | |
c802d64a | 141 | kprobe_opcode_t *slot = NULL; |
9ec4b1f3 | 142 | |
5b485629 | 143 | /* Since the slot array is not protected by rcu, we need a mutex */ |
c802d64a | 144 | mutex_lock(&c->mutex); |
6f716acd | 145 | retry: |
5b485629 MH |
146 | rcu_read_lock(); |
147 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
4610ee1d | 148 | if (kip->nused < slots_per_page(c)) { |
9ec4b1f3 | 149 | int i; |
4610ee1d | 150 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
151 | if (kip->slot_used[i] == SLOT_CLEAN) { |
152 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 153 | kip->nused++; |
c802d64a | 154 | slot = kip->insns + (i * c->insn_size); |
5b485629 | 155 | rcu_read_unlock(); |
c802d64a | 156 | goto out; |
9ec4b1f3 AM |
157 | } |
158 | } | |
4610ee1d MH |
159 | /* kip->nused is broken. Fix it. */ |
160 | kip->nused = slots_per_page(c); | |
161 | WARN_ON(1); | |
9ec4b1f3 AM |
162 | } |
163 | } | |
5b485629 | 164 | rcu_read_unlock(); |
9ec4b1f3 | 165 | |
b4c6c34a | 166 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 167 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 168 | goto retry; |
4610ee1d MH |
169 | |
170 | /* All out of space. Need to allocate a new page. */ | |
171 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); | |
6f716acd | 172 | if (!kip) |
c802d64a | 173 | goto out; |
9ec4b1f3 AM |
174 | |
175 | /* | |
176 | * Use module_alloc so this page is within +/- 2GB of where the | |
177 | * kernel image and loaded module images reside. This is required | |
178 | * so x86_64 can correctly handle the %rip-relative fixups. | |
179 | */ | |
af96397d | 180 | kip->insns = c->alloc(); |
9ec4b1f3 AM |
181 | if (!kip->insns) { |
182 | kfree(kip); | |
c802d64a | 183 | goto out; |
9ec4b1f3 | 184 | } |
c5cb5a2d | 185 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 186 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 187 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 188 | kip->nused = 1; |
b4c6c34a | 189 | kip->ngarbage = 0; |
af96397d | 190 | kip->cache = c; |
5b485629 | 191 | list_add_rcu(&kip->list, &c->pages); |
c802d64a | 192 | slot = kip->insns; |
69e49088 AH |
193 | |
194 | /* Record the perf ksymbol register event after adding the page */ | |
195 | perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns, | |
196 | PAGE_SIZE, false, c->sym); | |
c802d64a HC |
197 | out: |
198 | mutex_unlock(&c->mutex); | |
199 | return slot; | |
12941560 MH |
200 | } |
201 | ||
b4c6c34a | 202 | /* Return 1 if all garbages are collected, otherwise 0. */ |
55479f64 | 203 | static int collect_one_slot(struct kprobe_insn_page *kip, int idx) |
b4c6c34a | 204 | { |
ab40c5c6 | 205 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
206 | kip->nused--; |
207 | if (kip->nused == 0) { | |
208 | /* | |
209 | * Page is no longer in use. Free it unless | |
210 | * it's the last one. We keep the last one | |
211 | * so as not to have to set it up again the | |
212 | * next time somebody inserts a probe. | |
213 | */ | |
4610ee1d | 214 | if (!list_is_singular(&kip->list)) { |
69e49088 AH |
215 | /* |
216 | * Record perf ksymbol unregister event before removing | |
217 | * the page. | |
218 | */ | |
219 | perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, | |
220 | (unsigned long)kip->insns, PAGE_SIZE, true, | |
221 | kip->cache->sym); | |
5b485629 MH |
222 | list_del_rcu(&kip->list); |
223 | synchronize_rcu(); | |
af96397d | 224 | kip->cache->free(kip->insns); |
b4c6c34a MH |
225 | kfree(kip); |
226 | } | |
227 | return 1; | |
228 | } | |
229 | return 0; | |
230 | } | |
231 | ||
55479f64 | 232 | static int collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 233 | { |
c5cb5a2d | 234 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 235 | |
615d0ebb | 236 | /* Ensure no-one is interrupted on the garbages */ |
ae8b7ce7 | 237 | synchronize_rcu(); |
b4c6c34a | 238 | |
4610ee1d | 239 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 240 | int i; |
b4c6c34a MH |
241 | if (kip->ngarbage == 0) |
242 | continue; | |
243 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 244 | for (i = 0; i < slots_per_page(c); i++) { |
5b485629 | 245 | if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i)) |
b4c6c34a MH |
246 | break; |
247 | } | |
248 | } | |
4610ee1d | 249 | c->nr_garbage = 0; |
b4c6c34a MH |
250 | return 0; |
251 | } | |
252 | ||
55479f64 MH |
253 | void __free_insn_slot(struct kprobe_insn_cache *c, |
254 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
255 | { |
256 | struct kprobe_insn_page *kip; | |
5b485629 | 257 | long idx; |
9ec4b1f3 | 258 | |
c802d64a | 259 | mutex_lock(&c->mutex); |
5b485629 MH |
260 | rcu_read_lock(); |
261 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
262 | idx = ((long)slot - (long)kip->insns) / | |
263 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
264 | if (idx >= 0 && idx < slots_per_page(c)) | |
c802d64a | 265 | goto out; |
9ec4b1f3 | 266 | } |
5b485629 | 267 | /* Could not find this slot. */ |
4610ee1d | 268 | WARN_ON(1); |
5b485629 | 269 | kip = NULL; |
c802d64a | 270 | out: |
5b485629 MH |
271 | rcu_read_unlock(); |
272 | /* Mark and sweep: this may sleep */ | |
273 | if (kip) { | |
274 | /* Check double free */ | |
275 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
276 | if (dirty) { | |
277 | kip->slot_used[idx] = SLOT_DIRTY; | |
278 | kip->ngarbage++; | |
279 | if (++c->nr_garbage > slots_per_page(c)) | |
280 | collect_garbage_slots(c); | |
281 | } else { | |
282 | collect_one_slot(kip, idx); | |
283 | } | |
284 | } | |
c802d64a | 285 | mutex_unlock(&c->mutex); |
4610ee1d | 286 | } |
6f716acd | 287 | |
5b485629 MH |
288 | /* |
289 | * Check given address is on the page of kprobe instruction slots. | |
290 | * This will be used for checking whether the address on a stack | |
291 | * is on a text area or not. | |
292 | */ | |
293 | bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr) | |
294 | { | |
295 | struct kprobe_insn_page *kip; | |
296 | bool ret = false; | |
297 | ||
298 | rcu_read_lock(); | |
299 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
300 | if (addr >= (unsigned long)kip->insns && | |
301 | addr < (unsigned long)kip->insns + PAGE_SIZE) { | |
302 | ret = true; | |
303 | break; | |
304 | } | |
305 | } | |
306 | rcu_read_unlock(); | |
307 | ||
308 | return ret; | |
309 | } | |
310 | ||
d002b8bc AH |
311 | int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum, |
312 | unsigned long *value, char *type, char *sym) | |
313 | { | |
314 | struct kprobe_insn_page *kip; | |
315 | int ret = -ERANGE; | |
316 | ||
317 | rcu_read_lock(); | |
318 | list_for_each_entry_rcu(kip, &c->pages, list) { | |
319 | if ((*symnum)--) | |
320 | continue; | |
321 | strlcpy(sym, c->sym, KSYM_NAME_LEN); | |
322 | *type = 't'; | |
323 | *value = (unsigned long)kip->insns; | |
324 | ret = 0; | |
325 | break; | |
326 | } | |
327 | rcu_read_unlock(); | |
328 | ||
329 | return ret; | |
330 | } | |
331 | ||
afd66255 MH |
332 | #ifdef CONFIG_OPTPROBES |
333 | /* For optimized_kprobe buffer */ | |
c802d64a HC |
334 | struct kprobe_insn_cache kprobe_optinsn_slots = { |
335 | .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), | |
af96397d HC |
336 | .alloc = alloc_insn_page, |
337 | .free = free_insn_page, | |
d002b8bc | 338 | .sym = KPROBE_OPTINSN_PAGE_SYM, |
afd66255 MH |
339 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
340 | /* .insn_size is initialized later */ | |
341 | .nr_garbage = 0, | |
342 | }; | |
afd66255 | 343 | #endif |
2d14e39d | 344 | #endif |
9ec4b1f3 | 345 | |
e6584523 AM |
346 | /* We have preemption disabled.. so it is safe to use __ versions */ |
347 | static inline void set_kprobe_instance(struct kprobe *kp) | |
348 | { | |
b76834bc | 349 | __this_cpu_write(kprobe_instance, kp); |
e6584523 AM |
350 | } |
351 | ||
352 | static inline void reset_kprobe_instance(void) | |
353 | { | |
b76834bc | 354 | __this_cpu_write(kprobe_instance, NULL); |
e6584523 AM |
355 | } |
356 | ||
3516a460 AM |
357 | /* |
358 | * This routine is called either: | |
49a2a1b8 | 359 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 360 | * OR |
d217d545 | 361 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 362 | */ |
820aede0 | 363 | struct kprobe *get_kprobe(void *addr) |
1da177e4 LT |
364 | { |
365 | struct hlist_head *head; | |
3516a460 | 366 | struct kprobe *p; |
1da177e4 LT |
367 | |
368 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
6743ad43 MH |
369 | hlist_for_each_entry_rcu(p, head, hlist, |
370 | lockdep_is_held(&kprobe_mutex)) { | |
1da177e4 LT |
371 | if (p->addr == addr) |
372 | return p; | |
373 | } | |
afd66255 | 374 | |
1da177e4 LT |
375 | return NULL; |
376 | } | |
820aede0 | 377 | NOKPROBE_SYMBOL(get_kprobe); |
1da177e4 | 378 | |
820aede0 | 379 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
afd66255 MH |
380 | |
381 | /* Return true if the kprobe is an aggregator */ | |
382 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
383 | { | |
384 | return p->pre_handler == aggr_pre_handler; | |
385 | } | |
386 | ||
6274de49 MH |
387 | /* Return true(!0) if the kprobe is unused */ |
388 | static inline int kprobe_unused(struct kprobe *p) | |
389 | { | |
390 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && | |
391 | list_empty(&p->list); | |
392 | } | |
393 | ||
afd66255 MH |
394 | /* |
395 | * Keep all fields in the kprobe consistent | |
396 | */ | |
6d8e40a8 | 397 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 398 | { |
6d8e40a8 MH |
399 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
400 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
401 | } |
402 | ||
403 | #ifdef CONFIG_OPTPROBES | |
b2be84df MH |
404 | /* NOTE: change this value only with kprobe_mutex held */ |
405 | static bool kprobes_allow_optimization; | |
406 | ||
afd66255 MH |
407 | /* |
408 | * Call all pre_handler on the list, but ignores its return value. | |
409 | * This must be called from arch-dep optimized caller. | |
410 | */ | |
820aede0 | 411 | void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
afd66255 MH |
412 | { |
413 | struct kprobe *kp; | |
414 | ||
415 | list_for_each_entry_rcu(kp, &p->list, list) { | |
416 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
417 | set_kprobe_instance(kp); | |
4f3a8714 | 418 | kp->pre_handler(kp, regs); |
afd66255 MH |
419 | } |
420 | reset_kprobe_instance(); | |
421 | } | |
422 | } | |
820aede0 | 423 | NOKPROBE_SYMBOL(opt_pre_handler); |
afd66255 | 424 | |
6274de49 | 425 | /* Free optimized instructions and optimized_kprobe */ |
55479f64 | 426 | static void free_aggr_kprobe(struct kprobe *p) |
6274de49 MH |
427 | { |
428 | struct optimized_kprobe *op; | |
429 | ||
430 | op = container_of(p, struct optimized_kprobe, kp); | |
431 | arch_remove_optimized_kprobe(op); | |
432 | arch_remove_kprobe(p); | |
433 | kfree(op); | |
434 | } | |
435 | ||
afd66255 MH |
436 | /* Return true(!0) if the kprobe is ready for optimization. */ |
437 | static inline int kprobe_optready(struct kprobe *p) | |
438 | { | |
439 | struct optimized_kprobe *op; | |
440 | ||
441 | if (kprobe_aggrprobe(p)) { | |
442 | op = container_of(p, struct optimized_kprobe, kp); | |
443 | return arch_prepared_optinsn(&op->optinsn); | |
444 | } | |
445 | ||
446 | return 0; | |
447 | } | |
448 | ||
6274de49 MH |
449 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
450 | static inline int kprobe_disarmed(struct kprobe *p) | |
451 | { | |
452 | struct optimized_kprobe *op; | |
453 | ||
454 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ | |
455 | if (!kprobe_aggrprobe(p)) | |
456 | return kprobe_disabled(p); | |
457 | ||
458 | op = container_of(p, struct optimized_kprobe, kp); | |
459 | ||
460 | return kprobe_disabled(p) && list_empty(&op->list); | |
461 | } | |
462 | ||
463 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ | |
55479f64 | 464 | static int kprobe_queued(struct kprobe *p) |
6274de49 MH |
465 | { |
466 | struct optimized_kprobe *op; | |
467 | ||
468 | if (kprobe_aggrprobe(p)) { | |
469 | op = container_of(p, struct optimized_kprobe, kp); | |
470 | if (!list_empty(&op->list)) | |
471 | return 1; | |
472 | } | |
473 | return 0; | |
474 | } | |
475 | ||
afd66255 MH |
476 | /* |
477 | * Return an optimized kprobe whose optimizing code replaces | |
478 | * instructions including addr (exclude breakpoint). | |
479 | */ | |
55479f64 | 480 | static struct kprobe *get_optimized_kprobe(unsigned long addr) |
afd66255 MH |
481 | { |
482 | int i; | |
483 | struct kprobe *p = NULL; | |
484 | struct optimized_kprobe *op; | |
485 | ||
486 | /* Don't check i == 0, since that is a breakpoint case. */ | |
487 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
488 | p = get_kprobe((void *)(addr - i)); | |
489 | ||
490 | if (p && kprobe_optready(p)) { | |
491 | op = container_of(p, struct optimized_kprobe, kp); | |
492 | if (arch_within_optimized_kprobe(op, addr)) | |
493 | return p; | |
494 | } | |
495 | ||
496 | return NULL; | |
497 | } | |
498 | ||
499 | /* Optimization staging list, protected by kprobe_mutex */ | |
500 | static LIST_HEAD(optimizing_list); | |
6274de49 | 501 | static LIST_HEAD(unoptimizing_list); |
7b959fc5 | 502 | static LIST_HEAD(freeing_list); |
afd66255 MH |
503 | |
504 | static void kprobe_optimizer(struct work_struct *work); | |
505 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
506 | #define OPTIMIZE_DELAY 5 | |
507 | ||
61f4e13f MH |
508 | /* |
509 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
510 | * optimizing_list. | |
511 | */ | |
55479f64 | 512 | static void do_optimize_kprobes(void) |
afd66255 | 513 | { |
f1c6ece2 | 514 | lockdep_assert_held(&text_mutex); |
afd66255 MH |
515 | /* |
516 | * The optimization/unoptimization refers online_cpus via | |
517 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
518 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
519 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
520 | * text_mutex but stop_machine can not be done because online_cpus | |
521 | * has been changed) | |
2d1e38f5 | 522 | * To avoid this deadlock, caller must have locked cpu hotplug |
afd66255 MH |
523 | * for preventing cpu-hotplug outside of text_mutex locking. |
524 | */ | |
2d1e38f5 TG |
525 | lockdep_assert_cpus_held(); |
526 | ||
527 | /* Optimization never be done when disarmed */ | |
528 | if (kprobes_all_disarmed || !kprobes_allow_optimization || | |
529 | list_empty(&optimizing_list)) | |
530 | return; | |
531 | ||
cd7ebe22 | 532 | arch_optimize_kprobes(&optimizing_list); |
61f4e13f MH |
533 | } |
534 | ||
6274de49 MH |
535 | /* |
536 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint | |
537 | * if need) kprobes listed on unoptimizing_list. | |
538 | */ | |
55479f64 | 539 | static void do_unoptimize_kprobes(void) |
6274de49 MH |
540 | { |
541 | struct optimized_kprobe *op, *tmp; | |
542 | ||
f1c6ece2 | 543 | lockdep_assert_held(&text_mutex); |
2d1e38f5 TG |
544 | /* See comment in do_optimize_kprobes() */ |
545 | lockdep_assert_cpus_held(); | |
546 | ||
6274de49 MH |
547 | /* Unoptimization must be done anytime */ |
548 | if (list_empty(&unoptimizing_list)) | |
549 | return; | |
550 | ||
7b959fc5 | 551 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
f984ba4e | 552 | /* Loop free_list for disarming */ |
7b959fc5 | 553 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
f66c0447 MH |
554 | /* Switching from detour code to origin */ |
555 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
6274de49 MH |
556 | /* Disarm probes if marked disabled */ |
557 | if (kprobe_disabled(&op->kp)) | |
558 | arch_disarm_kprobe(&op->kp); | |
559 | if (kprobe_unused(&op->kp)) { | |
560 | /* | |
561 | * Remove unused probes from hash list. After waiting | |
562 | * for synchronization, these probes are reclaimed. | |
563 | * (reclaiming is done by do_free_cleaned_kprobes.) | |
564 | */ | |
565 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
566 | } else |
567 | list_del_init(&op->list); | |
568 | } | |
6274de49 MH |
569 | } |
570 | ||
571 | /* Reclaim all kprobes on the free_list */ | |
55479f64 | 572 | static void do_free_cleaned_kprobes(void) |
6274de49 MH |
573 | { |
574 | struct optimized_kprobe *op, *tmp; | |
575 | ||
7b959fc5 | 576 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 | 577 | list_del_init(&op->list); |
cbdd96f5 MH |
578 | if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) { |
579 | /* | |
580 | * This must not happen, but if there is a kprobe | |
581 | * still in use, keep it on kprobes hash list. | |
582 | */ | |
583 | continue; | |
584 | } | |
6274de49 MH |
585 | free_aggr_kprobe(&op->kp); |
586 | } | |
587 | } | |
588 | ||
589 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
55479f64 | 590 | static void kick_kprobe_optimizer(void) |
6274de49 | 591 | { |
ad72b3be | 592 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de49 MH |
593 | } |
594 | ||
61f4e13f | 595 | /* Kprobe jump optimizer */ |
55479f64 | 596 | static void kprobe_optimizer(struct work_struct *work) |
61f4e13f | 597 | { |
72ef3794 | 598 | mutex_lock(&kprobe_mutex); |
2d1e38f5 | 599 | cpus_read_lock(); |
f1c6ece2 | 600 | mutex_lock(&text_mutex); |
61f4e13f MH |
601 | |
602 | /* | |
6274de49 MH |
603 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
604 | * kprobes before waiting for quiesence period. | |
605 | */ | |
7b959fc5 | 606 | do_unoptimize_kprobes(); |
6274de49 MH |
607 | |
608 | /* | |
a30b85df MH |
609 | * Step 2: Wait for quiesence period to ensure all potentially |
610 | * preempted tasks to have normally scheduled. Because optprobe | |
611 | * may modify multiple instructions, there is a chance that Nth | |
612 | * instruction is preempted. In that case, such tasks can return | |
613 | * to 2nd-Nth byte of jump instruction. This wait is for avoiding it. | |
614 | * Note that on non-preemptive kernel, this is transparently converted | |
615 | * to synchronoze_sched() to wait for all interrupts to have completed. | |
61f4e13f | 616 | */ |
a30b85df | 617 | synchronize_rcu_tasks(); |
61f4e13f | 618 | |
6274de49 | 619 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 620 | do_optimize_kprobes(); |
6274de49 MH |
621 | |
622 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
7b959fc5 | 623 | do_free_cleaned_kprobes(); |
6274de49 | 624 | |
f1c6ece2 | 625 | mutex_unlock(&text_mutex); |
2d1e38f5 | 626 | cpus_read_unlock(); |
6274de49 | 627 | |
cd7ebe22 | 628 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 629 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 | 630 | kick_kprobe_optimizer(); |
1a0aa991 MH |
631 | |
632 | mutex_unlock(&kprobe_mutex); | |
6274de49 MH |
633 | } |
634 | ||
635 | /* Wait for completing optimization and unoptimization */ | |
30e7d894 | 636 | void wait_for_kprobe_optimizer(void) |
6274de49 | 637 | { |
ad72b3be TH |
638 | mutex_lock(&kprobe_mutex); |
639 | ||
640 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { | |
641 | mutex_unlock(&kprobe_mutex); | |
642 | ||
643 | /* this will also make optimizing_work execute immmediately */ | |
644 | flush_delayed_work(&optimizing_work); | |
645 | /* @optimizing_work might not have been queued yet, relax */ | |
646 | cpu_relax(); | |
647 | ||
648 | mutex_lock(&kprobe_mutex); | |
649 | } | |
650 | ||
651 | mutex_unlock(&kprobe_mutex); | |
afd66255 MH |
652 | } |
653 | ||
e4add247 MH |
654 | static bool optprobe_queued_unopt(struct optimized_kprobe *op) |
655 | { | |
656 | struct optimized_kprobe *_op; | |
657 | ||
658 | list_for_each_entry(_op, &unoptimizing_list, list) { | |
659 | if (op == _op) | |
660 | return true; | |
661 | } | |
662 | ||
663 | return false; | |
664 | } | |
665 | ||
afd66255 | 666 | /* Optimize kprobe if p is ready to be optimized */ |
55479f64 | 667 | static void optimize_kprobe(struct kprobe *p) |
afd66255 MH |
668 | { |
669 | struct optimized_kprobe *op; | |
670 | ||
671 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 672 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
673 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
674 | return; | |
675 | ||
059053a2 MH |
676 | /* kprobes with post_handler can not be optimized */ |
677 | if (p->post_handler) | |
afd66255 MH |
678 | return; |
679 | ||
680 | op = container_of(p, struct optimized_kprobe, kp); | |
681 | ||
682 | /* Check there is no other kprobes at the optimized instructions */ | |
683 | if (arch_check_optimized_kprobe(op) < 0) | |
684 | return; | |
685 | ||
686 | /* Check if it is already optimized. */ | |
e4add247 MH |
687 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) { |
688 | if (optprobe_queued_unopt(op)) { | |
689 | /* This is under unoptimizing. Just dequeue the probe */ | |
690 | list_del_init(&op->list); | |
691 | } | |
afd66255 | 692 | return; |
e4add247 | 693 | } |
afd66255 | 694 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 | 695 | |
e4add247 MH |
696 | /* On unoptimizing/optimizing_list, op must have OPTIMIZED flag */ |
697 | if (WARN_ON_ONCE(!list_empty(&op->list))) | |
698 | return; | |
699 | ||
700 | list_add(&op->list, &optimizing_list); | |
701 | kick_kprobe_optimizer(); | |
6274de49 MH |
702 | } |
703 | ||
704 | /* Short cut to direct unoptimizing */ | |
55479f64 | 705 | static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
6274de49 | 706 | { |
2d1e38f5 | 707 | lockdep_assert_cpus_held(); |
6274de49 | 708 | arch_unoptimize_kprobe(op); |
f66c0447 | 709 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
afd66255 MH |
710 | } |
711 | ||
712 | /* Unoptimize a kprobe if p is optimized */ | |
55479f64 | 713 | static void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
714 | { |
715 | struct optimized_kprobe *op; | |
716 | ||
6274de49 MH |
717 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
718 | return; /* This is not an optprobe nor optimized */ | |
719 | ||
720 | op = container_of(p, struct optimized_kprobe, kp); | |
e4add247 | 721 | if (!kprobe_optimized(p)) |
6274de49 | 722 | return; |
6274de49 | 723 | |
6274de49 | 724 | if (!list_empty(&op->list)) { |
e4add247 MH |
725 | if (optprobe_queued_unopt(op)) { |
726 | /* Queued in unoptimizing queue */ | |
727 | if (force) { | |
728 | /* | |
729 | * Forcibly unoptimize the kprobe here, and queue it | |
730 | * in the freeing list for release afterwards. | |
731 | */ | |
732 | force_unoptimize_kprobe(op); | |
733 | list_move(&op->list, &freeing_list); | |
734 | } | |
735 | } else { | |
736 | /* Dequeue from the optimizing queue */ | |
737 | list_del_init(&op->list); | |
738 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
739 | } | |
6274de49 MH |
740 | return; |
741 | } | |
e4add247 | 742 | |
6274de49 | 743 | /* Optimized kprobe case */ |
e4add247 | 744 | if (force) { |
6274de49 MH |
745 | /* Forcibly update the code: this is a special case */ |
746 | force_unoptimize_kprobe(op); | |
e4add247 | 747 | } else { |
6274de49 MH |
748 | list_add(&op->list, &unoptimizing_list); |
749 | kick_kprobe_optimizer(); | |
afd66255 MH |
750 | } |
751 | } | |
752 | ||
0490cd1f | 753 | /* Cancel unoptimizing for reusing */ |
819319fc | 754 | static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f MH |
755 | { |
756 | struct optimized_kprobe *op; | |
757 | ||
0490cd1f MH |
758 | /* |
759 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
760 | * there is still a relative jump) and disabled. | |
761 | */ | |
762 | op = container_of(ap, struct optimized_kprobe, kp); | |
4458515b | 763 | WARN_ON_ONCE(list_empty(&op->list)); |
0490cd1f MH |
764 | /* Enable the probe again */ |
765 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
766 | /* Optimize it again (remove from op->list) */ | |
5f843ed4 MH |
767 | if (!kprobe_optready(ap)) |
768 | return -EINVAL; | |
819319fc | 769 | |
0490cd1f | 770 | optimize_kprobe(ap); |
819319fc | 771 | return 0; |
0490cd1f MH |
772 | } |
773 | ||
afd66255 | 774 | /* Remove optimized instructions */ |
55479f64 | 775 | static void kill_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
776 | { |
777 | struct optimized_kprobe *op; | |
778 | ||
779 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
780 | if (!list_empty(&op->list)) |
781 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 782 | list_del_init(&op->list); |
6274de49 | 783 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc5 MH |
784 | |
785 | if (kprobe_unused(p)) { | |
786 | /* Enqueue if it is unused */ | |
787 | list_add(&op->list, &freeing_list); | |
788 | /* | |
789 | * Remove unused probes from the hash list. After waiting | |
790 | * for synchronization, this probe is reclaimed. | |
791 | * (reclaiming is done by do_free_cleaned_kprobes().) | |
792 | */ | |
793 | hlist_del_rcu(&op->kp.hlist); | |
794 | } | |
795 | ||
6274de49 | 796 | /* Don't touch the code, because it is already freed. */ |
afd66255 MH |
797 | arch_remove_optimized_kprobe(op); |
798 | } | |
799 | ||
a460246c MH |
800 | static inline |
801 | void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) | |
802 | { | |
803 | if (!kprobe_ftrace(p)) | |
804 | arch_prepare_optimized_kprobe(op, p); | |
805 | } | |
806 | ||
afd66255 | 807 | /* Try to prepare optimized instructions */ |
55479f64 | 808 | static void prepare_optimized_kprobe(struct kprobe *p) |
afd66255 MH |
809 | { |
810 | struct optimized_kprobe *op; | |
811 | ||
812 | op = container_of(p, struct optimized_kprobe, kp); | |
a460246c | 813 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
814 | } |
815 | ||
afd66255 | 816 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
55479f64 | 817 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
818 | { |
819 | struct optimized_kprobe *op; | |
820 | ||
821 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
822 | if (!op) | |
823 | return NULL; | |
824 | ||
825 | INIT_LIST_HEAD(&op->list); | |
826 | op->kp.addr = p->addr; | |
a460246c | 827 | __prepare_optimized_kprobe(op, p); |
afd66255 MH |
828 | |
829 | return &op->kp; | |
830 | } | |
831 | ||
55479f64 | 832 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
afd66255 MH |
833 | |
834 | /* | |
835 | * Prepare an optimized_kprobe and optimize it | |
836 | * NOTE: p must be a normal registered kprobe | |
837 | */ | |
55479f64 | 838 | static void try_to_optimize_kprobe(struct kprobe *p) |
afd66255 MH |
839 | { |
840 | struct kprobe *ap; | |
841 | struct optimized_kprobe *op; | |
842 | ||
ae6aa16f MH |
843 | /* Impossible to optimize ftrace-based kprobe */ |
844 | if (kprobe_ftrace(p)) | |
845 | return; | |
846 | ||
25764288 | 847 | /* For preparing optimization, jump_label_text_reserved() is called */ |
2d1e38f5 | 848 | cpus_read_lock(); |
25764288 MH |
849 | jump_label_lock(); |
850 | mutex_lock(&text_mutex); | |
851 | ||
afd66255 MH |
852 | ap = alloc_aggr_kprobe(p); |
853 | if (!ap) | |
25764288 | 854 | goto out; |
afd66255 MH |
855 | |
856 | op = container_of(ap, struct optimized_kprobe, kp); | |
857 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
858 | /* If failed to setup optimizing, fallback to kprobe */ | |
6274de49 MH |
859 | arch_remove_optimized_kprobe(op); |
860 | kfree(op); | |
25764288 | 861 | goto out; |
afd66255 MH |
862 | } |
863 | ||
864 | init_aggr_kprobe(ap, p); | |
25764288 MH |
865 | optimize_kprobe(ap); /* This just kicks optimizer thread */ |
866 | ||
867 | out: | |
868 | mutex_unlock(&text_mutex); | |
869 | jump_label_unlock(); | |
2d1e38f5 | 870 | cpus_read_unlock(); |
afd66255 MH |
871 | } |
872 | ||
b2be84df | 873 | #ifdef CONFIG_SYSCTL |
55479f64 | 874 | static void optimize_all_kprobes(void) |
b2be84df MH |
875 | { |
876 | struct hlist_head *head; | |
b2be84df MH |
877 | struct kprobe *p; |
878 | unsigned int i; | |
879 | ||
5c51543b | 880 | mutex_lock(&kprobe_mutex); |
b2be84df MH |
881 | /* If optimization is already allowed, just return */ |
882 | if (kprobes_allow_optimization) | |
5c51543b | 883 | goto out; |
b2be84df | 884 | |
2d1e38f5 | 885 | cpus_read_lock(); |
b2be84df | 886 | kprobes_allow_optimization = true; |
b2be84df MH |
887 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
888 | head = &kprobe_table[i]; | |
7e6a71d8 | 889 | hlist_for_each_entry(p, head, hlist) |
b2be84df MH |
890 | if (!kprobe_disabled(p)) |
891 | optimize_kprobe(p); | |
892 | } | |
2d1e38f5 | 893 | cpus_read_unlock(); |
b2be84df | 894 | printk(KERN_INFO "Kprobes globally optimized\n"); |
5c51543b MH |
895 | out: |
896 | mutex_unlock(&kprobe_mutex); | |
b2be84df MH |
897 | } |
898 | ||
55479f64 | 899 | static void unoptimize_all_kprobes(void) |
b2be84df MH |
900 | { |
901 | struct hlist_head *head; | |
b2be84df MH |
902 | struct kprobe *p; |
903 | unsigned int i; | |
904 | ||
5c51543b | 905 | mutex_lock(&kprobe_mutex); |
b2be84df | 906 | /* If optimization is already prohibited, just return */ |
5c51543b MH |
907 | if (!kprobes_allow_optimization) { |
908 | mutex_unlock(&kprobe_mutex); | |
b2be84df | 909 | return; |
5c51543b | 910 | } |
b2be84df | 911 | |
2d1e38f5 | 912 | cpus_read_lock(); |
b2be84df | 913 | kprobes_allow_optimization = false; |
b2be84df MH |
914 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
915 | head = &kprobe_table[i]; | |
7e6a71d8 | 916 | hlist_for_each_entry(p, head, hlist) { |
b2be84df | 917 | if (!kprobe_disabled(p)) |
6274de49 | 918 | unoptimize_kprobe(p, false); |
b2be84df MH |
919 | } |
920 | } | |
2d1e38f5 | 921 | cpus_read_unlock(); |
5c51543b MH |
922 | mutex_unlock(&kprobe_mutex); |
923 | ||
6274de49 MH |
924 | /* Wait for unoptimizing completion */ |
925 | wait_for_kprobe_optimizer(); | |
926 | printk(KERN_INFO "Kprobes globally unoptimized\n"); | |
b2be84df MH |
927 | } |
928 | ||
5c51543b | 929 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
b2be84df MH |
930 | int sysctl_kprobes_optimization; |
931 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, | |
32927393 | 932 | void *buffer, size_t *length, |
b2be84df MH |
933 | loff_t *ppos) |
934 | { | |
935 | int ret; | |
936 | ||
5c51543b | 937 | mutex_lock(&kprobe_sysctl_mutex); |
b2be84df MH |
938 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
939 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
940 | ||
941 | if (sysctl_kprobes_optimization) | |
942 | optimize_all_kprobes(); | |
943 | else | |
944 | unoptimize_all_kprobes(); | |
5c51543b | 945 | mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df MH |
946 | |
947 | return ret; | |
948 | } | |
949 | #endif /* CONFIG_SYSCTL */ | |
950 | ||
6274de49 | 951 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
55479f64 | 952 | static void __arm_kprobe(struct kprobe *p) |
afd66255 | 953 | { |
6d8e40a8 | 954 | struct kprobe *_p; |
afd66255 MH |
955 | |
956 | /* Check collision with other optimized kprobes */ | |
6d8e40a8 MH |
957 | _p = get_optimized_kprobe((unsigned long)p->addr); |
958 | if (unlikely(_p)) | |
6274de49 MH |
959 | /* Fallback to unoptimized kprobe */ |
960 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
961 | |
962 | arch_arm_kprobe(p); | |
963 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
964 | } | |
965 | ||
6274de49 | 966 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
55479f64 | 967 | static void __disarm_kprobe(struct kprobe *p, bool reopt) |
afd66255 | 968 | { |
6d8e40a8 | 969 | struct kprobe *_p; |
afd66255 | 970 | |
69d54b91 WN |
971 | /* Try to unoptimize */ |
972 | unoptimize_kprobe(p, kprobes_all_disarmed); | |
afd66255 | 973 | |
6274de49 MH |
974 | if (!kprobe_queued(p)) { |
975 | arch_disarm_kprobe(p); | |
976 | /* If another kprobe was blocked, optimize it. */ | |
977 | _p = get_optimized_kprobe((unsigned long)p->addr); | |
978 | if (unlikely(_p) && reopt) | |
979 | optimize_kprobe(_p); | |
980 | } | |
981 | /* TODO: reoptimize others after unoptimized this probe */ | |
afd66255 MH |
982 | } |
983 | ||
984 | #else /* !CONFIG_OPTPROBES */ | |
985 | ||
986 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 987 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
988 | #define kill_optimized_kprobe(p) do {} while (0) |
989 | #define prepare_optimized_kprobe(p) do {} while (0) | |
990 | #define try_to_optimize_kprobe(p) do {} while (0) | |
991 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
992 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
993 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
994 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 995 | |
819319fc | 996 | static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f | 997 | { |
819319fc MH |
998 | /* |
999 | * If the optimized kprobe is NOT supported, the aggr kprobe is | |
1000 | * released at the same time that the last aggregated kprobe is | |
1001 | * unregistered. | |
1002 | * Thus there should be no chance to reuse unused kprobe. | |
1003 | */ | |
0490cd1f | 1004 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); |
819319fc | 1005 | return -EINVAL; |
0490cd1f MH |
1006 | } |
1007 | ||
55479f64 | 1008 | static void free_aggr_kprobe(struct kprobe *p) |
afd66255 | 1009 | { |
6274de49 | 1010 | arch_remove_kprobe(p); |
afd66255 MH |
1011 | kfree(p); |
1012 | } | |
1013 | ||
55479f64 | 1014 | static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255 MH |
1015 | { |
1016 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
1017 | } | |
1018 | #endif /* CONFIG_OPTPROBES */ | |
1019 | ||
e7dbfe34 | 1020 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 1021 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
0bc11ed5 MH |
1022 | .func = kprobe_ftrace_handler, |
1023 | .flags = FTRACE_OPS_FL_SAVE_REGS, | |
1024 | }; | |
1025 | ||
1026 | static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = { | |
e5253896 | 1027 | .func = kprobe_ftrace_handler, |
1d70be34 | 1028 | .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
ae6aa16f | 1029 | }; |
0bc11ed5 MH |
1030 | |
1031 | static int kprobe_ipmodify_enabled; | |
ae6aa16f MH |
1032 | static int kprobe_ftrace_enabled; |
1033 | ||
1034 | /* Must ensure p->addr is really on ftrace */ | |
55479f64 | 1035 | static int prepare_kprobe(struct kprobe *p) |
ae6aa16f MH |
1036 | { |
1037 | if (!kprobe_ftrace(p)) | |
1038 | return arch_prepare_kprobe(p); | |
1039 | ||
1040 | return arch_prepare_kprobe_ftrace(p); | |
1041 | } | |
1042 | ||
1043 | /* Caller must lock kprobe_mutex */ | |
0bc11ed5 MH |
1044 | static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
1045 | int *cnt) | |
ae6aa16f | 1046 | { |
12310e34 | 1047 | int ret = 0; |
ae6aa16f | 1048 | |
0bc11ed5 | 1049 | ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); |
12310e34 | 1050 | if (ret) { |
4458515b MH |
1051 | pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", |
1052 | p->addr, ret); | |
12310e34 JY |
1053 | return ret; |
1054 | } | |
1055 | ||
0bc11ed5 MH |
1056 | if (*cnt == 0) { |
1057 | ret = register_ftrace_function(ops); | |
12310e34 JY |
1058 | if (ret) { |
1059 | pr_debug("Failed to init kprobe-ftrace (%d)\n", ret); | |
1060 | goto err_ftrace; | |
1061 | } | |
ae6aa16f | 1062 | } |
12310e34 | 1063 | |
0bc11ed5 | 1064 | (*cnt)++; |
12310e34 JY |
1065 | return ret; |
1066 | ||
1067 | err_ftrace: | |
1068 | /* | |
0bc11ed5 MH |
1069 | * At this point, sinec ops is not registered, we should be sefe from |
1070 | * registering empty filter. | |
12310e34 | 1071 | */ |
0bc11ed5 | 1072 | ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
12310e34 | 1073 | return ret; |
ae6aa16f MH |
1074 | } |
1075 | ||
0bc11ed5 MH |
1076 | static int arm_kprobe_ftrace(struct kprobe *p) |
1077 | { | |
1078 | bool ipmodify = (p->post_handler != NULL); | |
1079 | ||
1080 | return __arm_kprobe_ftrace(p, | |
1081 | ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, | |
1082 | ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); | |
1083 | } | |
1084 | ||
ae6aa16f | 1085 | /* Caller must lock kprobe_mutex */ |
0bc11ed5 MH |
1086 | static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, |
1087 | int *cnt) | |
ae6aa16f | 1088 | { |
297f9233 | 1089 | int ret = 0; |
ae6aa16f | 1090 | |
0bc11ed5 MH |
1091 | if (*cnt == 1) { |
1092 | ret = unregister_ftrace_function(ops); | |
297f9233 JY |
1093 | if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret)) |
1094 | return ret; | |
ae6aa16f | 1095 | } |
297f9233 | 1096 | |
0bc11ed5 | 1097 | (*cnt)--; |
297f9233 | 1098 | |
0bc11ed5 | 1099 | ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
4458515b MH |
1100 | WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", |
1101 | p->addr, ret); | |
297f9233 | 1102 | return ret; |
ae6aa16f | 1103 | } |
0bc11ed5 MH |
1104 | |
1105 | static int disarm_kprobe_ftrace(struct kprobe *p) | |
1106 | { | |
1107 | bool ipmodify = (p->post_handler != NULL); | |
1108 | ||
1109 | return __disarm_kprobe_ftrace(p, | |
1110 | ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, | |
1111 | ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); | |
1112 | } | |
e7dbfe34 | 1113 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
10de795a MS |
1114 | static inline int prepare_kprobe(struct kprobe *p) |
1115 | { | |
1116 | return arch_prepare_kprobe(p); | |
1117 | } | |
1118 | ||
1119 | static inline int arm_kprobe_ftrace(struct kprobe *p) | |
1120 | { | |
1121 | return -ENODEV; | |
1122 | } | |
1123 | ||
1124 | static inline int disarm_kprobe_ftrace(struct kprobe *p) | |
1125 | { | |
1126 | return -ENODEV; | |
1127 | } | |
ae6aa16f MH |
1128 | #endif |
1129 | ||
201517a7 | 1130 | /* Arm a kprobe with text_mutex */ |
12310e34 | 1131 | static int arm_kprobe(struct kprobe *kp) |
201517a7 | 1132 | { |
12310e34 JY |
1133 | if (unlikely(kprobe_ftrace(kp))) |
1134 | return arm_kprobe_ftrace(kp); | |
1135 | ||
2d1e38f5 | 1136 | cpus_read_lock(); |
201517a7 | 1137 | mutex_lock(&text_mutex); |
afd66255 | 1138 | __arm_kprobe(kp); |
201517a7 | 1139 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1140 | cpus_read_unlock(); |
12310e34 JY |
1141 | |
1142 | return 0; | |
201517a7 MH |
1143 | } |
1144 | ||
1145 | /* Disarm a kprobe with text_mutex */ | |
297f9233 | 1146 | static int disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 1147 | { |
297f9233 JY |
1148 | if (unlikely(kprobe_ftrace(kp))) |
1149 | return disarm_kprobe_ftrace(kp); | |
2d1e38f5 TG |
1150 | |
1151 | cpus_read_lock(); | |
201517a7 | 1152 | mutex_lock(&text_mutex); |
ae6aa16f | 1153 | __disarm_kprobe(kp, reopt); |
201517a7 | 1154 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1155 | cpus_read_unlock(); |
297f9233 JY |
1156 | |
1157 | return 0; | |
201517a7 MH |
1158 | } |
1159 | ||
64f562c6 AM |
1160 | /* |
1161 | * Aggregate handlers for multiple kprobes support - these handlers | |
1162 | * take care of invoking the individual kprobe handlers on p->list | |
1163 | */ | |
820aede0 | 1164 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
1165 | { |
1166 | struct kprobe *kp; | |
1167 | ||
3516a460 | 1168 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1169 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1170 | set_kprobe_instance(kp); |
8b0914ea PP |
1171 | if (kp->pre_handler(kp, regs)) |
1172 | return 1; | |
64f562c6 | 1173 | } |
e6584523 | 1174 | reset_kprobe_instance(); |
64f562c6 AM |
1175 | } |
1176 | return 0; | |
1177 | } | |
820aede0 | 1178 | NOKPROBE_SYMBOL(aggr_pre_handler); |
64f562c6 | 1179 | |
820aede0 MH |
1180 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1181 | unsigned long flags) | |
64f562c6 AM |
1182 | { |
1183 | struct kprobe *kp; | |
1184 | ||
3516a460 | 1185 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1186 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1187 | set_kprobe_instance(kp); |
64f562c6 | 1188 | kp->post_handler(kp, regs, flags); |
e6584523 | 1189 | reset_kprobe_instance(); |
64f562c6 AM |
1190 | } |
1191 | } | |
64f562c6 | 1192 | } |
820aede0 | 1193 | NOKPROBE_SYMBOL(aggr_post_handler); |
64f562c6 | 1194 | |
820aede0 MH |
1195 | static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
1196 | int trapnr) | |
64f562c6 | 1197 | { |
b76834bc | 1198 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 | 1199 | |
64f562c6 AM |
1200 | /* |
1201 | * if we faulted "during" the execution of a user specified | |
1202 | * probe handler, invoke just that probe's fault handler | |
1203 | */ | |
e6584523 AM |
1204 | if (cur && cur->fault_handler) { |
1205 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
1206 | return 1; |
1207 | } | |
1208 | return 0; | |
1209 | } | |
820aede0 | 1210 | NOKPROBE_SYMBOL(aggr_fault_handler); |
64f562c6 | 1211 | |
bf8d5c52 | 1212 | /* Walks the list and increments nmissed count for multiprobe case */ |
820aede0 | 1213 | void kprobes_inc_nmissed_count(struct kprobe *p) |
bf8d5c52 KA |
1214 | { |
1215 | struct kprobe *kp; | |
afd66255 | 1216 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1217 | p->nmissed++; |
1218 | } else { | |
1219 | list_for_each_entry_rcu(kp, &p->list, list) | |
1220 | kp->nmissed++; | |
1221 | } | |
1222 | return; | |
1223 | } | |
820aede0 | 1224 | NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
bf8d5c52 | 1225 | |
820aede0 MH |
1226 | void recycle_rp_inst(struct kretprobe_instance *ri, |
1227 | struct hlist_head *head) | |
b94cce92 | 1228 | { |
ef53d9c5 S |
1229 | struct kretprobe *rp = ri->rp; |
1230 | ||
b94cce92 HN |
1231 | /* remove rp inst off the rprobe_inst_table */ |
1232 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
1233 | INIT_HLIST_NODE(&ri->hlist); |
1234 | if (likely(rp)) { | |
ec484608 | 1235 | raw_spin_lock(&rp->lock); |
ef53d9c5 | 1236 | hlist_add_head(&ri->hlist, &rp->free_instances); |
ec484608 | 1237 | raw_spin_unlock(&rp->lock); |
b94cce92 HN |
1238 | } else |
1239 | /* Unregistering */ | |
99219a3f | 1240 | hlist_add_head(&ri->hlist, head); |
b94cce92 | 1241 | } |
820aede0 | 1242 | NOKPROBE_SYMBOL(recycle_rp_inst); |
b94cce92 | 1243 | |
820aede0 | 1244 | void kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 | 1245 | struct hlist_head **head, unsigned long *flags) |
635c17c2 | 1246 | __acquires(hlist_lock) |
ef53d9c5 S |
1247 | { |
1248 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1249 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1250 | |
1251 | *head = &kretprobe_inst_table[hash]; | |
1252 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1253 | raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5 | 1254 | } |
820aede0 | 1255 | NOKPROBE_SYMBOL(kretprobe_hash_lock); |
ef53d9c5 | 1256 | |
820aede0 MH |
1257 | static void kretprobe_table_lock(unsigned long hash, |
1258 | unsigned long *flags) | |
635c17c2 | 1259 | __acquires(hlist_lock) |
b94cce92 | 1260 | { |
ec484608 TG |
1261 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1262 | raw_spin_lock_irqsave(hlist_lock, *flags); | |
ef53d9c5 | 1263 | } |
820aede0 | 1264 | NOKPROBE_SYMBOL(kretprobe_table_lock); |
ef53d9c5 | 1265 | |
820aede0 MH |
1266 | void kretprobe_hash_unlock(struct task_struct *tsk, |
1267 | unsigned long *flags) | |
635c17c2 | 1268 | __releases(hlist_lock) |
ef53d9c5 S |
1269 | { |
1270 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1271 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1272 | |
1273 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1274 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
ef53d9c5 | 1275 | } |
820aede0 | 1276 | NOKPROBE_SYMBOL(kretprobe_hash_unlock); |
ef53d9c5 | 1277 | |
820aede0 MH |
1278 | static void kretprobe_table_unlock(unsigned long hash, |
1279 | unsigned long *flags) | |
635c17c2 | 1280 | __releases(hlist_lock) |
ef53d9c5 | 1281 | { |
ec484608 TG |
1282 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1283 | raw_spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 | 1284 | } |
820aede0 | 1285 | NOKPROBE_SYMBOL(kretprobe_table_unlock); |
b94cce92 | 1286 | |
9b38cc70 JO |
1287 | struct kprobe kprobe_busy = { |
1288 | .addr = (void *) get_kprobe, | |
1289 | }; | |
1290 | ||
1291 | void kprobe_busy_begin(void) | |
1292 | { | |
1293 | struct kprobe_ctlblk *kcb; | |
1294 | ||
1295 | preempt_disable(); | |
1296 | __this_cpu_write(current_kprobe, &kprobe_busy); | |
1297 | kcb = get_kprobe_ctlblk(); | |
1298 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; | |
1299 | } | |
1300 | ||
1301 | void kprobe_busy_end(void) | |
1302 | { | |
1303 | __this_cpu_write(current_kprobe, NULL); | |
1304 | preempt_enable(); | |
1305 | } | |
1306 | ||
b94cce92 | 1307 | /* |
c6fd91f0 | 1308 | * This function is called from finish_task_switch when task tk becomes dead, |
1309 | * so that we can recycle any function-return probe instances associated | |
1310 | * with this task. These left over instances represent probed functions | |
1311 | * that have been called but will never return. | |
b94cce92 | 1312 | */ |
820aede0 | 1313 | void kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 1314 | { |
62c27be0 | 1315 | struct kretprobe_instance *ri; |
99219a3f | 1316 | struct hlist_head *head, empty_rp; |
b67bfe0d | 1317 | struct hlist_node *tmp; |
ef53d9c5 | 1318 | unsigned long hash, flags = 0; |
802eae7c | 1319 | |
ef53d9c5 S |
1320 | if (unlikely(!kprobes_initialized)) |
1321 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
1322 | return; | |
1323 | ||
9b38cc70 JO |
1324 | kprobe_busy_begin(); |
1325 | ||
d496aab5 | 1326 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 S |
1327 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1328 | head = &kretprobe_inst_table[hash]; | |
1329 | kretprobe_table_lock(hash, &flags); | |
b67bfe0d | 1330 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
62c27be0 | 1331 | if (ri->task == tk) |
99219a3f | 1332 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 1333 | } |
ef53d9c5 | 1334 | kretprobe_table_unlock(hash, &flags); |
b67bfe0d | 1335 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
99219a3f | 1336 | hlist_del(&ri->hlist); |
1337 | kfree(ri); | |
1338 | } | |
9b38cc70 JO |
1339 | |
1340 | kprobe_busy_end(); | |
b94cce92 | 1341 | } |
820aede0 | 1342 | NOKPROBE_SYMBOL(kprobe_flush_task); |
b94cce92 | 1343 | |
b94cce92 HN |
1344 | static inline void free_rp_inst(struct kretprobe *rp) |
1345 | { | |
1346 | struct kretprobe_instance *ri; | |
b67bfe0d | 1347 | struct hlist_node *next; |
4c4308cb | 1348 | |
b67bfe0d | 1349 | hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) { |
ef53d9c5 | 1350 | hlist_del(&ri->hlist); |
b94cce92 HN |
1351 | kfree(ri); |
1352 | } | |
1353 | } | |
1354 | ||
820aede0 | 1355 | static void cleanup_rp_inst(struct kretprobe *rp) |
4a296e07 | 1356 | { |
ef53d9c5 | 1357 | unsigned long flags, hash; |
4a296e07 | 1358 | struct kretprobe_instance *ri; |
b67bfe0d | 1359 | struct hlist_node *next; |
ef53d9c5 S |
1360 | struct hlist_head *head; |
1361 | ||
4a296e07 | 1362 | /* No race here */ |
ef53d9c5 S |
1363 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1364 | kretprobe_table_lock(hash, &flags); | |
1365 | head = &kretprobe_inst_table[hash]; | |
b67bfe0d | 1366 | hlist_for_each_entry_safe(ri, next, head, hlist) { |
ef53d9c5 S |
1367 | if (ri->rp == rp) |
1368 | ri->rp = NULL; | |
1369 | } | |
1370 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 1371 | } |
4a296e07 MH |
1372 | free_rp_inst(rp); |
1373 | } | |
820aede0 | 1374 | NOKPROBE_SYMBOL(cleanup_rp_inst); |
4a296e07 | 1375 | |
059053a2 | 1376 | /* Add the new probe to ap->list */ |
55479f64 | 1377 | static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1378 | { |
059053a2 | 1379 | if (p->post_handler) |
6274de49 | 1380 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1381 | |
059053a2 | 1382 | list_add_rcu(&p->list, &ap->list); |
b918e5e6 MH |
1383 | if (p->post_handler && !ap->post_handler) |
1384 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1385 | |
8b0914ea PP |
1386 | return 0; |
1387 | } | |
1388 | ||
64f562c6 AM |
1389 | /* |
1390 | * Fill in the required fields of the "manager kprobe". Replace the | |
1391 | * earlier kprobe in the hlist with the manager kprobe | |
1392 | */ | |
55479f64 | 1393 | static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1394 | { |
afd66255 | 1395 | /* Copy p's insn slot to ap */ |
8b0914ea | 1396 | copy_kprobe(p, ap); |
a9ad965e | 1397 | flush_insn_slot(ap); |
64f562c6 | 1398 | ap->addr = p->addr; |
afd66255 | 1399 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1400 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 1401 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
1402 | /* We don't care the kprobe which has gone. */ |
1403 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1404 | ap->post_handler = aggr_post_handler; |
64f562c6 AM |
1405 | |
1406 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1407 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1408 | |
afd66255 | 1409 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1410 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1411 | } |
1412 | ||
1413 | /* | |
1414 | * This is the second or subsequent kprobe at the address - handle | |
1415 | * the intricacies | |
64f562c6 | 1416 | */ |
55479f64 | 1417 | static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
64f562c6 AM |
1418 | { |
1419 | int ret = 0; | |
6d8e40a8 | 1420 | struct kprobe *ap = orig_p; |
64f562c6 | 1421 | |
2d1e38f5 TG |
1422 | cpus_read_lock(); |
1423 | ||
25764288 MH |
1424 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1425 | jump_label_lock(); | |
25764288 MH |
1426 | mutex_lock(&text_mutex); |
1427 | ||
6d8e40a8 MH |
1428 | if (!kprobe_aggrprobe(orig_p)) { |
1429 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
1430 | ap = alloc_aggr_kprobe(orig_p); | |
25764288 MH |
1431 | if (!ap) { |
1432 | ret = -ENOMEM; | |
1433 | goto out; | |
1434 | } | |
6d8e40a8 | 1435 | init_aggr_kprobe(ap, orig_p); |
819319fc | 1436 | } else if (kprobe_unused(ap)) { |
0490cd1f | 1437 | /* This probe is going to die. Rescue it */ |
819319fc MH |
1438 | ret = reuse_unused_kprobe(ap); |
1439 | if (ret) | |
1440 | goto out; | |
1441 | } | |
b918e5e6 MH |
1442 | |
1443 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1444 | /* |
1445 | * Attempting to insert new probe at the same location that | |
1446 | * had a probe in the module vaddr area which already | |
1447 | * freed. So, the instruction slot has already been | |
1448 | * released. We need a new slot for the new probe. | |
1449 | */ | |
b918e5e6 | 1450 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1451 | if (ret) |
b918e5e6 MH |
1452 | /* |
1453 | * Even if fail to allocate new slot, don't need to | |
1454 | * free aggr_probe. It will be used next time, or | |
1455 | * freed by unregister_kprobe. | |
1456 | */ | |
25764288 | 1457 | goto out; |
de5bd88d | 1458 | |
afd66255 MH |
1459 | /* Prepare optimized instructions if possible. */ |
1460 | prepare_optimized_kprobe(ap); | |
1461 | ||
e8386a0c | 1462 | /* |
de5bd88d MH |
1463 | * Clear gone flag to prevent allocating new slot again, and |
1464 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1465 | */ |
de5bd88d MH |
1466 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1467 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1468 | } |
b918e5e6 | 1469 | |
afd66255 | 1470 | /* Copy ap's insn slot to p */ |
b918e5e6 | 1471 | copy_kprobe(ap, p); |
25764288 MH |
1472 | ret = add_new_kprobe(ap, p); |
1473 | ||
1474 | out: | |
1475 | mutex_unlock(&text_mutex); | |
25764288 | 1476 | jump_label_unlock(); |
2d1e38f5 | 1477 | cpus_read_unlock(); |
25764288 MH |
1478 | |
1479 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1480 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
12310e34 | 1481 | if (!kprobes_all_disarmed) { |
25764288 | 1482 | /* Arm the breakpoint again. */ |
12310e34 JY |
1483 | ret = arm_kprobe(ap); |
1484 | if (ret) { | |
1485 | ap->flags |= KPROBE_FLAG_DISABLED; | |
1486 | list_del_rcu(&p->list); | |
ae8b7ce7 | 1487 | synchronize_rcu(); |
12310e34 JY |
1488 | } |
1489 | } | |
25764288 MH |
1490 | } |
1491 | return ret; | |
64f562c6 AM |
1492 | } |
1493 | ||
be8f2743 MH |
1494 | bool __weak arch_within_kprobe_blacklist(unsigned long addr) |
1495 | { | |
1496 | /* The __kprobes marked functions and entry code must not be probed */ | |
1497 | return addr >= (unsigned long)__kprobes_text_start && | |
1498 | addr < (unsigned long)__kprobes_text_end; | |
1499 | } | |
1500 | ||
6143c6fb | 1501 | static bool __within_kprobe_blacklist(unsigned long addr) |
d0aaff97 | 1502 | { |
376e2424 | 1503 | struct kprobe_blacklist_entry *ent; |
3d8d996e | 1504 | |
be8f2743 | 1505 | if (arch_within_kprobe_blacklist(addr)) |
376e2424 | 1506 | return true; |
3d8d996e SD |
1507 | /* |
1508 | * If there exists a kprobe_blacklist, verify and | |
1509 | * fail any probe registration in the prohibited area | |
1510 | */ | |
376e2424 MH |
1511 | list_for_each_entry(ent, &kprobe_blacklist, list) { |
1512 | if (addr >= ent->start_addr && addr < ent->end_addr) | |
1513 | return true; | |
3d8d996e | 1514 | } |
6143c6fb MH |
1515 | return false; |
1516 | } | |
376e2424 | 1517 | |
6143c6fb MH |
1518 | bool within_kprobe_blacklist(unsigned long addr) |
1519 | { | |
1520 | char symname[KSYM_NAME_LEN], *p; | |
1521 | ||
1522 | if (__within_kprobe_blacklist(addr)) | |
1523 | return true; | |
1524 | ||
1525 | /* Check if the address is on a suffixed-symbol */ | |
1526 | if (!lookup_symbol_name(addr, symname)) { | |
1527 | p = strchr(symname, '.'); | |
1528 | if (!p) | |
1529 | return false; | |
1530 | *p = '\0'; | |
1531 | addr = (unsigned long)kprobe_lookup_name(symname, 0); | |
1532 | if (addr) | |
1533 | return __within_kprobe_blacklist(addr); | |
1534 | } | |
376e2424 | 1535 | return false; |
d0aaff97 PP |
1536 | } |
1537 | ||
b2a5cd69 MH |
1538 | /* |
1539 | * If we have a symbol_name argument, look it up and add the offset field | |
1540 | * to it. This way, we can specify a relative address to a symbol. | |
bc81d48d MH |
1541 | * This returns encoded errors if it fails to look up symbol or invalid |
1542 | * combination of parameters. | |
b2a5cd69 | 1543 | */ |
1d585e70 NR |
1544 | static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr, |
1545 | const char *symbol_name, unsigned int offset) | |
b2a5cd69 | 1546 | { |
1d585e70 | 1547 | if ((symbol_name && addr) || (!symbol_name && !addr)) |
bc81d48d MH |
1548 | goto invalid; |
1549 | ||
1d585e70 | 1550 | if (symbol_name) { |
7246f600 | 1551 | addr = kprobe_lookup_name(symbol_name, offset); |
bc81d48d MH |
1552 | if (!addr) |
1553 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1554 | } |
1555 | ||
1d585e70 | 1556 | addr = (kprobe_opcode_t *)(((char *)addr) + offset); |
bc81d48d MH |
1557 | if (addr) |
1558 | return addr; | |
1559 | ||
1560 | invalid: | |
1561 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1562 | } |
1563 | ||
1d585e70 NR |
1564 | static kprobe_opcode_t *kprobe_addr(struct kprobe *p) |
1565 | { | |
1566 | return _kprobe_addr(p->addr, p->symbol_name, p->offset); | |
1567 | } | |
1568 | ||
1f0ab409 | 1569 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
55479f64 | 1570 | static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
1f0ab409 | 1571 | { |
6d8e40a8 | 1572 | struct kprobe *ap, *list_p; |
1f0ab409 | 1573 | |
7e6a71d8 MH |
1574 | lockdep_assert_held(&kprobe_mutex); |
1575 | ||
6d8e40a8 MH |
1576 | ap = get_kprobe(p->addr); |
1577 | if (unlikely(!ap)) | |
1f0ab409 AM |
1578 | return NULL; |
1579 | ||
6d8e40a8 | 1580 | if (p != ap) { |
7e6a71d8 | 1581 | list_for_each_entry(list_p, &ap->list, list) |
1f0ab409 AM |
1582 | if (list_p == p) |
1583 | /* kprobe p is a valid probe */ | |
1584 | goto valid; | |
1585 | return NULL; | |
1586 | } | |
1587 | valid: | |
6d8e40a8 | 1588 | return ap; |
1f0ab409 AM |
1589 | } |
1590 | ||
1591 | /* Return error if the kprobe is being re-registered */ | |
1592 | static inline int check_kprobe_rereg(struct kprobe *p) | |
1593 | { | |
1594 | int ret = 0; | |
1f0ab409 AM |
1595 | |
1596 | mutex_lock(&kprobe_mutex); | |
6d8e40a8 | 1597 | if (__get_valid_kprobe(p)) |
1f0ab409 AM |
1598 | ret = -EINVAL; |
1599 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1600 | |
1f0ab409 AM |
1601 | return ret; |
1602 | } | |
1603 | ||
f7f242ff | 1604 | int __weak arch_check_ftrace_location(struct kprobe *p) |
1da177e4 | 1605 | { |
ae6aa16f MH |
1606 | unsigned long ftrace_addr; |
1607 | ||
ae6aa16f MH |
1608 | ftrace_addr = ftrace_location((unsigned long)p->addr); |
1609 | if (ftrace_addr) { | |
e7dbfe34 | 1610 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f MH |
1611 | /* Given address is not on the instruction boundary */ |
1612 | if ((unsigned long)p->addr != ftrace_addr) | |
1613 | return -EILSEQ; | |
ae6aa16f | 1614 | p->flags |= KPROBE_FLAG_FTRACE; |
e7dbfe34 | 1615 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
1616 | return -EINVAL; |
1617 | #endif | |
1618 | } | |
f7f242ff HC |
1619 | return 0; |
1620 | } | |
1621 | ||
1622 | static int check_kprobe_address_safe(struct kprobe *p, | |
1623 | struct module **probed_mod) | |
1624 | { | |
1625 | int ret; | |
1f0ab409 | 1626 | |
f7f242ff HC |
1627 | ret = arch_check_ftrace_location(p); |
1628 | if (ret) | |
1629 | return ret; | |
91bad2f8 | 1630 | jump_label_lock(); |
de31c3ca | 1631 | preempt_disable(); |
f7fa6ef0 MH |
1632 | |
1633 | /* Ensure it is not in reserved area nor out of text */ | |
ec30c5f3 | 1634 | if (!kernel_text_address((unsigned long) p->addr) || |
376e2424 | 1635 | within_kprobe_blacklist((unsigned long) p->addr) || |
e336b402 MH |
1636 | jump_label_text_reserved(p->addr, p->addr) || |
1637 | find_bug((unsigned long)p->addr)) { | |
f986a499 | 1638 | ret = -EINVAL; |
f7fa6ef0 | 1639 | goto out; |
f986a499 | 1640 | } |
b3e55c72 | 1641 | |
f7fa6ef0 MH |
1642 | /* Check if are we probing a module */ |
1643 | *probed_mod = __module_text_address((unsigned long) p->addr); | |
1644 | if (*probed_mod) { | |
6f716acd | 1645 | /* |
e8386a0c MH |
1646 | * We must hold a refcount of the probed module while updating |
1647 | * its code to prohibit unexpected unloading. | |
df019b1d | 1648 | */ |
f7fa6ef0 MH |
1649 | if (unlikely(!try_module_get(*probed_mod))) { |
1650 | ret = -ENOENT; | |
1651 | goto out; | |
1652 | } | |
de31c3ca | 1653 | |
f24659d9 MH |
1654 | /* |
1655 | * If the module freed .init.text, we couldn't insert | |
1656 | * kprobes in there. | |
1657 | */ | |
f7fa6ef0 MH |
1658 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
1659 | (*probed_mod)->state != MODULE_STATE_COMING) { | |
1660 | module_put(*probed_mod); | |
1661 | *probed_mod = NULL; | |
1662 | ret = -ENOENT; | |
f24659d9 | 1663 | } |
df019b1d | 1664 | } |
f7fa6ef0 | 1665 | out: |
a189d035 | 1666 | preempt_enable(); |
de31c3ca | 1667 | jump_label_unlock(); |
1da177e4 | 1668 | |
f7fa6ef0 MH |
1669 | return ret; |
1670 | } | |
1671 | ||
55479f64 | 1672 | int register_kprobe(struct kprobe *p) |
f7fa6ef0 MH |
1673 | { |
1674 | int ret; | |
1675 | struct kprobe *old_p; | |
1676 | struct module *probed_mod; | |
1677 | kprobe_opcode_t *addr; | |
1678 | ||
1679 | /* Adjust probe address from symbol */ | |
1680 | addr = kprobe_addr(p); | |
1681 | if (IS_ERR(addr)) | |
1682 | return PTR_ERR(addr); | |
1683 | p->addr = addr; | |
1684 | ||
1685 | ret = check_kprobe_rereg(p); | |
1686 | if (ret) | |
1687 | return ret; | |
1688 | ||
1689 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ | |
1690 | p->flags &= KPROBE_FLAG_DISABLED; | |
3516a460 | 1691 | p->nmissed = 0; |
9861668f | 1692 | INIT_LIST_HEAD(&p->list); |
afd66255 | 1693 | |
f7fa6ef0 MH |
1694 | ret = check_kprobe_address_safe(p, &probed_mod); |
1695 | if (ret) | |
1696 | return ret; | |
1697 | ||
1698 | mutex_lock(&kprobe_mutex); | |
afd66255 | 1699 | |
64f562c6 AM |
1700 | old_p = get_kprobe(p->addr); |
1701 | if (old_p) { | |
afd66255 | 1702 | /* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6 | 1703 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1704 | goto out; |
1705 | } | |
1da177e4 | 1706 | |
2d1e38f5 TG |
1707 | cpus_read_lock(); |
1708 | /* Prevent text modification */ | |
1709 | mutex_lock(&text_mutex); | |
ae6aa16f | 1710 | ret = prepare_kprobe(p); |
25764288 | 1711 | mutex_unlock(&text_mutex); |
2d1e38f5 | 1712 | cpus_read_unlock(); |
6f716acd | 1713 | if (ret) |
afd66255 | 1714 | goto out; |
49a2a1b8 | 1715 | |
64f562c6 | 1716 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1717 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1718 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1719 | ||
12310e34 JY |
1720 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) { |
1721 | ret = arm_kprobe(p); | |
1722 | if (ret) { | |
1723 | hlist_del_rcu(&p->hlist); | |
ae8b7ce7 | 1724 | synchronize_rcu(); |
12310e34 JY |
1725 | goto out; |
1726 | } | |
1727 | } | |
afd66255 MH |
1728 | |
1729 | /* Try to optimize kprobe */ | |
1730 | try_to_optimize_kprobe(p); | |
1da177e4 | 1731 | out: |
7a7d1cf9 | 1732 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1733 | |
e8386a0c | 1734 | if (probed_mod) |
df019b1d | 1735 | module_put(probed_mod); |
e8386a0c | 1736 | |
1da177e4 LT |
1737 | return ret; |
1738 | } | |
99081ab5 | 1739 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1740 | |
6f0f1dd7 | 1741 | /* Check if all probes on the aggrprobe are disabled */ |
55479f64 | 1742 | static int aggr_kprobe_disabled(struct kprobe *ap) |
6f0f1dd7 MH |
1743 | { |
1744 | struct kprobe *kp; | |
1745 | ||
7e6a71d8 MH |
1746 | lockdep_assert_held(&kprobe_mutex); |
1747 | ||
1748 | list_for_each_entry(kp, &ap->list, list) | |
6f0f1dd7 MH |
1749 | if (!kprobe_disabled(kp)) |
1750 | /* | |
1751 | * There is an active probe on the list. | |
1752 | * We can't disable this ap. | |
1753 | */ | |
1754 | return 0; | |
1755 | ||
1756 | return 1; | |
1757 | } | |
1758 | ||
1759 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ | |
55479f64 | 1760 | static struct kprobe *__disable_kprobe(struct kprobe *p) |
6f0f1dd7 MH |
1761 | { |
1762 | struct kprobe *orig_p; | |
297f9233 | 1763 | int ret; |
6f0f1dd7 MH |
1764 | |
1765 | /* Get an original kprobe for return */ | |
1766 | orig_p = __get_valid_kprobe(p); | |
1767 | if (unlikely(orig_p == NULL)) | |
297f9233 | 1768 | return ERR_PTR(-EINVAL); |
6f0f1dd7 MH |
1769 | |
1770 | if (!kprobe_disabled(p)) { | |
1771 | /* Disable probe if it is a child probe */ | |
1772 | if (p != orig_p) | |
1773 | p->flags |= KPROBE_FLAG_DISABLED; | |
1774 | ||
1775 | /* Try to disarm and disable this/parent probe */ | |
1776 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
69d54b91 WN |
1777 | /* |
1778 | * If kprobes_all_disarmed is set, orig_p | |
1779 | * should have already been disarmed, so | |
1780 | * skip unneed disarming process. | |
1781 | */ | |
297f9233 JY |
1782 | if (!kprobes_all_disarmed) { |
1783 | ret = disarm_kprobe(orig_p, true); | |
1784 | if (ret) { | |
1785 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1786 | return ERR_PTR(ret); | |
1787 | } | |
1788 | } | |
6f0f1dd7 MH |
1789 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1790 | } | |
1791 | } | |
1792 | ||
1793 | return orig_p; | |
1794 | } | |
1795 | ||
de5bd88d MH |
1796 | /* |
1797 | * Unregister a kprobe without a scheduler synchronization. | |
1798 | */ | |
55479f64 | 1799 | static int __unregister_kprobe_top(struct kprobe *p) |
de5bd88d | 1800 | { |
6d8e40a8 | 1801 | struct kprobe *ap, *list_p; |
de5bd88d | 1802 | |
6f0f1dd7 MH |
1803 | /* Disable kprobe. This will disarm it if needed. */ |
1804 | ap = __disable_kprobe(p); | |
297f9233 JY |
1805 | if (IS_ERR(ap)) |
1806 | return PTR_ERR(ap); | |
de5bd88d | 1807 | |
6f0f1dd7 | 1808 | if (ap == p) |
bf8f6e5b | 1809 | /* |
6f0f1dd7 MH |
1810 | * This probe is an independent(and non-optimized) kprobe |
1811 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1812 | */ |
6f0f1dd7 MH |
1813 | goto disarmed; |
1814 | ||
1815 | /* Following process expects this probe is an aggrprobe */ | |
1816 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1817 | ||
6274de49 MH |
1818 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1819 | /* | |
1820 | * !disarmed could be happen if the probe is under delayed | |
1821 | * unoptimizing. | |
1822 | */ | |
6f0f1dd7 MH |
1823 | goto disarmed; |
1824 | else { | |
1825 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1826 | if (p->post_handler && !kprobe_gone(p)) { |
7e6a71d8 | 1827 | list_for_each_entry(list_p, &ap->list, list) { |
9861668f MH |
1828 | if ((list_p != p) && (list_p->post_handler)) |
1829 | goto noclean; | |
1830 | } | |
6d8e40a8 | 1831 | ap->post_handler = NULL; |
9861668f MH |
1832 | } |
1833 | noclean: | |
6f0f1dd7 MH |
1834 | /* |
1835 | * Remove from the aggrprobe: this path will do nothing in | |
1836 | * __unregister_kprobe_bottom(). | |
1837 | */ | |
49a2a1b8 | 1838 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1839 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1840 | /* | |
1841 | * Try to optimize this probe again, because post | |
1842 | * handler may have been changed. | |
1843 | */ | |
1844 | optimize_kprobe(ap); | |
49a2a1b8 | 1845 | } |
9861668f | 1846 | return 0; |
6f0f1dd7 MH |
1847 | |
1848 | disarmed: | |
1849 | hlist_del_rcu(&ap->hlist); | |
1850 | return 0; | |
9861668f | 1851 | } |
3516a460 | 1852 | |
55479f64 | 1853 | static void __unregister_kprobe_bottom(struct kprobe *p) |
9861668f | 1854 | { |
6d8e40a8 | 1855 | struct kprobe *ap; |
b3e55c72 | 1856 | |
e8386a0c | 1857 | if (list_empty(&p->list)) |
6274de49 | 1858 | /* This is an independent kprobe */ |
0498b635 | 1859 | arch_remove_kprobe(p); |
e8386a0c | 1860 | else if (list_is_singular(&p->list)) { |
6274de49 | 1861 | /* This is the last child of an aggrprobe */ |
6d8e40a8 | 1862 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1863 | list_del(&p->list); |
6d8e40a8 | 1864 | free_aggr_kprobe(ap); |
9861668f | 1865 | } |
6274de49 | 1866 | /* Otherwise, do nothing. */ |
9861668f MH |
1867 | } |
1868 | ||
55479f64 | 1869 | int register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1870 | { |
1871 | int i, ret = 0; | |
1872 | ||
1873 | if (num <= 0) | |
1874 | return -EINVAL; | |
1875 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1876 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1877 | if (ret < 0) { |
1878 | if (i > 0) | |
1879 | unregister_kprobes(kps, i); | |
9861668f | 1880 | break; |
36721656 | 1881 | } |
49a2a1b8 | 1882 | } |
9861668f MH |
1883 | return ret; |
1884 | } | |
99081ab5 | 1885 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1886 | |
55479f64 | 1887 | void unregister_kprobe(struct kprobe *p) |
9861668f MH |
1888 | { |
1889 | unregister_kprobes(&p, 1); | |
1890 | } | |
99081ab5 | 1891 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1892 | |
55479f64 | 1893 | void unregister_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1894 | { |
1895 | int i; | |
1896 | ||
1897 | if (num <= 0) | |
1898 | return; | |
1899 | mutex_lock(&kprobe_mutex); | |
1900 | for (i = 0; i < num; i++) | |
1901 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1902 | kps[i]->addr = NULL; | |
1903 | mutex_unlock(&kprobe_mutex); | |
1904 | ||
ae8b7ce7 | 1905 | synchronize_rcu(); |
9861668f MH |
1906 | for (i = 0; i < num; i++) |
1907 | if (kps[i]->addr) | |
1908 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1909 | } |
99081ab5 | 1910 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 | 1911 | |
5f6bee34 NR |
1912 | int __weak kprobe_exceptions_notify(struct notifier_block *self, |
1913 | unsigned long val, void *data) | |
fc62d020 NR |
1914 | { |
1915 | return NOTIFY_DONE; | |
1916 | } | |
5f6bee34 | 1917 | NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
fc62d020 | 1918 | |
1da177e4 | 1919 | static struct notifier_block kprobe_exceptions_nb = { |
3d5631e0 AK |
1920 | .notifier_call = kprobe_exceptions_notify, |
1921 | .priority = 0x7fffffff /* we need to be notified first */ | |
1922 | }; | |
1923 | ||
3d7e3382 ME |
1924 | unsigned long __weak arch_deref_entry_point(void *entry) |
1925 | { | |
1926 | return (unsigned long)entry; | |
1927 | } | |
1da177e4 | 1928 | |
9edddaa2 | 1929 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1930 | /* |
1931 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1932 | * hits it will set up the return probe. | |
1933 | */ | |
820aede0 | 1934 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
e65cefe8 AB |
1935 | { |
1936 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1937 | unsigned long hash, flags = 0; |
1938 | struct kretprobe_instance *ri; | |
e65cefe8 | 1939 | |
f96f5678 MH |
1940 | /* |
1941 | * To avoid deadlocks, prohibit return probing in NMI contexts, | |
1942 | * just skip the probe and increase the (inexact) 'nmissed' | |
1943 | * statistical counter, so that the user is informed that | |
1944 | * something happened: | |
1945 | */ | |
1946 | if (unlikely(in_nmi())) { | |
1947 | rp->nmissed++; | |
1948 | return 0; | |
1949 | } | |
1950 | ||
1951 | /* TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 | 1952 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
ec484608 | 1953 | raw_spin_lock_irqsave(&rp->lock, flags); |
4c4308cb | 1954 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1955 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1956 | struct kretprobe_instance, hlist); |
1957 | hlist_del(&ri->hlist); | |
ec484608 | 1958 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1959 | |
4c4308cb CH |
1960 | ri->rp = rp; |
1961 | ri->task = current; | |
f47cd9b5 | 1962 | |
55ca6140 JL |
1963 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1964 | raw_spin_lock_irqsave(&rp->lock, flags); | |
1965 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
1966 | raw_spin_unlock_irqrestore(&rp->lock, flags); | |
f47cd9b5 | 1967 | return 0; |
55ca6140 | 1968 | } |
f47cd9b5 | 1969 | |
4c4308cb CH |
1970 | arch_prepare_kretprobe(ri, regs); |
1971 | ||
1972 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1973 | INIT_HLIST_NODE(&ri->hlist); |
1974 | kretprobe_table_lock(hash, &flags); | |
1975 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1976 | kretprobe_table_unlock(hash, &flags); | |
1977 | } else { | |
4c4308cb | 1978 | rp->nmissed++; |
ec484608 | 1979 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1980 | } |
e65cefe8 AB |
1981 | return 0; |
1982 | } | |
820aede0 | 1983 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
e65cefe8 | 1984 | |
659b957f | 1985 | bool __weak arch_kprobe_on_func_entry(unsigned long offset) |
90ec5e89 NR |
1986 | { |
1987 | return !offset; | |
1988 | } | |
1989 | ||
659b957f | 1990 | bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) |
1d585e70 NR |
1991 | { |
1992 | kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset); | |
1993 | ||
1994 | if (IS_ERR(kp_addr)) | |
1995 | return false; | |
1996 | ||
1997 | if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) || | |
659b957f | 1998 | !arch_kprobe_on_func_entry(offset)) |
1d585e70 NR |
1999 | return false; |
2000 | ||
2001 | return true; | |
2002 | } | |
2003 | ||
55479f64 | 2004 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
2005 | { |
2006 | int ret = 0; | |
2007 | struct kretprobe_instance *inst; | |
2008 | int i; | |
b2a5cd69 | 2009 | void *addr; |
90ec5e89 | 2010 | |
659b957f | 2011 | if (!kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset)) |
90ec5e89 | 2012 | return -EINVAL; |
f438d914 MH |
2013 | |
2014 | if (kretprobe_blacklist_size) { | |
b2a5cd69 | 2015 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
2016 | if (IS_ERR(addr)) |
2017 | return PTR_ERR(addr); | |
f438d914 MH |
2018 | |
2019 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
2020 | if (kretprobe_blacklist[i].addr == addr) | |
2021 | return -EINVAL; | |
2022 | } | |
2023 | } | |
b94cce92 HN |
2024 | |
2025 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
2026 | rp->kp.post_handler = NULL; |
2027 | rp->kp.fault_handler = NULL; | |
b94cce92 HN |
2028 | |
2029 | /* Pre-allocate memory for max kretprobe instances */ | |
2030 | if (rp->maxactive <= 0) { | |
92616606 | 2031 | #ifdef CONFIG_PREEMPTION |
c2ef6661 | 2032 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 2033 | #else |
4dae560f | 2034 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
2035 | #endif |
2036 | } | |
ec484608 | 2037 | raw_spin_lock_init(&rp->lock); |
b94cce92 HN |
2038 | INIT_HLIST_HEAD(&rp->free_instances); |
2039 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
2040 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
2041 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
2042 | if (inst == NULL) { |
2043 | free_rp_inst(rp); | |
2044 | return -ENOMEM; | |
2045 | } | |
ef53d9c5 S |
2046 | INIT_HLIST_NODE(&inst->hlist); |
2047 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
2048 | } |
2049 | ||
2050 | rp->nmissed = 0; | |
2051 | /* Establish function entry probe point */ | |
49ad2fd7 | 2052 | ret = register_kprobe(&rp->kp); |
4a296e07 | 2053 | if (ret != 0) |
b94cce92 HN |
2054 | free_rp_inst(rp); |
2055 | return ret; | |
2056 | } | |
99081ab5 | 2057 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2058 | |
55479f64 | 2059 | int register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2060 | { |
2061 | int ret = 0, i; | |
2062 | ||
2063 | if (num <= 0) | |
2064 | return -EINVAL; | |
2065 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 2066 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
2067 | if (ret < 0) { |
2068 | if (i > 0) | |
2069 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
2070 | break; |
2071 | } | |
2072 | } | |
2073 | return ret; | |
2074 | } | |
99081ab5 | 2075 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 2076 | |
55479f64 | 2077 | void unregister_kretprobe(struct kretprobe *rp) |
4a296e07 MH |
2078 | { |
2079 | unregister_kretprobes(&rp, 1); | |
2080 | } | |
99081ab5 | 2081 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 2082 | |
55479f64 | 2083 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2084 | { |
2085 | int i; | |
2086 | ||
2087 | if (num <= 0) | |
2088 | return; | |
2089 | mutex_lock(&kprobe_mutex); | |
2090 | for (i = 0; i < num; i++) | |
2091 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
2092 | rps[i]->kp.addr = NULL; | |
2093 | mutex_unlock(&kprobe_mutex); | |
2094 | ||
ae8b7ce7 | 2095 | synchronize_rcu(); |
4a296e07 MH |
2096 | for (i = 0; i < num; i++) { |
2097 | if (rps[i]->kp.addr) { | |
2098 | __unregister_kprobe_bottom(&rps[i]->kp); | |
2099 | cleanup_rp_inst(rps[i]); | |
2100 | } | |
2101 | } | |
2102 | } | |
99081ab5 | 2103 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 2104 | |
9edddaa2 | 2105 | #else /* CONFIG_KRETPROBES */ |
55479f64 | 2106 | int register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
2107 | { |
2108 | return -ENOSYS; | |
2109 | } | |
99081ab5 | 2110 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 2111 | |
55479f64 | 2112 | int register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 2113 | { |
4a296e07 | 2114 | return -ENOSYS; |
346fd59b | 2115 | } |
99081ab5 MH |
2116 | EXPORT_SYMBOL_GPL(register_kretprobes); |
2117 | ||
55479f64 | 2118 | void unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 2119 | { |
4a296e07 | 2120 | } |
99081ab5 | 2121 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 2122 | |
55479f64 | 2123 | void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
2124 | { |
2125 | } | |
99081ab5 | 2126 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 2127 | |
820aede0 | 2128 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
4a296e07 MH |
2129 | { |
2130 | return 0; | |
b94cce92 | 2131 | } |
820aede0 | 2132 | NOKPROBE_SYMBOL(pre_handler_kretprobe); |
b94cce92 | 2133 | |
4a296e07 MH |
2134 | #endif /* CONFIG_KRETPROBES */ |
2135 | ||
e8386a0c | 2136 | /* Set the kprobe gone and remove its instruction buffer. */ |
55479f64 | 2137 | static void kill_kprobe(struct kprobe *p) |
e8386a0c MH |
2138 | { |
2139 | struct kprobe *kp; | |
de5bd88d | 2140 | |
7e6a71d8 MH |
2141 | lockdep_assert_held(&kprobe_mutex); |
2142 | ||
e8386a0c | 2143 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 2144 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
2145 | /* |
2146 | * If this is an aggr_kprobe, we have to list all the | |
2147 | * chained probes and mark them GONE. | |
2148 | */ | |
7e6a71d8 | 2149 | list_for_each_entry(kp, &p->list, list) |
e8386a0c MH |
2150 | kp->flags |= KPROBE_FLAG_GONE; |
2151 | p->post_handler = NULL; | |
afd66255 | 2152 | kill_optimized_kprobe(p); |
e8386a0c MH |
2153 | } |
2154 | /* | |
2155 | * Here, we can remove insn_slot safely, because no thread calls | |
2156 | * the original probed function (which will be freed soon) any more. | |
2157 | */ | |
2158 | arch_remove_kprobe(p); | |
0cb2f137 MS |
2159 | |
2160 | /* | |
2161 | * The module is going away. We should disarm the kprobe which | |
2162 | * is using ftrace. | |
2163 | */ | |
2164 | if (kprobe_ftrace(p)) | |
2165 | disarm_kprobe_ftrace(p); | |
e8386a0c MH |
2166 | } |
2167 | ||
c0614829 | 2168 | /* Disable one kprobe */ |
55479f64 | 2169 | int disable_kprobe(struct kprobe *kp) |
c0614829 MH |
2170 | { |
2171 | int ret = 0; | |
297f9233 | 2172 | struct kprobe *p; |
c0614829 MH |
2173 | |
2174 | mutex_lock(&kprobe_mutex); | |
2175 | ||
6f0f1dd7 | 2176 | /* Disable this kprobe */ |
297f9233 JY |
2177 | p = __disable_kprobe(kp); |
2178 | if (IS_ERR(p)) | |
2179 | ret = PTR_ERR(p); | |
c0614829 | 2180 | |
c0614829 MH |
2181 | mutex_unlock(&kprobe_mutex); |
2182 | return ret; | |
2183 | } | |
2184 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
2185 | ||
2186 | /* Enable one kprobe */ | |
55479f64 | 2187 | int enable_kprobe(struct kprobe *kp) |
c0614829 MH |
2188 | { |
2189 | int ret = 0; | |
2190 | struct kprobe *p; | |
2191 | ||
2192 | mutex_lock(&kprobe_mutex); | |
2193 | ||
2194 | /* Check whether specified probe is valid. */ | |
2195 | p = __get_valid_kprobe(kp); | |
2196 | if (unlikely(p == NULL)) { | |
2197 | ret = -EINVAL; | |
2198 | goto out; | |
2199 | } | |
2200 | ||
2201 | if (kprobe_gone(kp)) { | |
2202 | /* This kprobe has gone, we couldn't enable it. */ | |
2203 | ret = -EINVAL; | |
2204 | goto out; | |
2205 | } | |
2206 | ||
2207 | if (p != kp) | |
2208 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
2209 | ||
2210 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
2211 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
12310e34 JY |
2212 | ret = arm_kprobe(p); |
2213 | if (ret) | |
2214 | p->flags |= KPROBE_FLAG_DISABLED; | |
c0614829 MH |
2215 | } |
2216 | out: | |
2217 | mutex_unlock(&kprobe_mutex); | |
2218 | return ret; | |
2219 | } | |
2220 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
2221 | ||
4458515b | 2222 | /* Caller must NOT call this in usual path. This is only for critical case */ |
820aede0 | 2223 | void dump_kprobe(struct kprobe *kp) |
24851d24 | 2224 | { |
4458515b MH |
2225 | pr_err("Dumping kprobe:\n"); |
2226 | pr_err("Name: %s\nOffset: %x\nAddress: %pS\n", | |
2227 | kp->symbol_name, kp->offset, kp->addr); | |
24851d24 | 2228 | } |
820aede0 | 2229 | NOKPROBE_SYMBOL(dump_kprobe); |
24851d24 | 2230 | |
fb1a59fa MH |
2231 | int kprobe_add_ksym_blacklist(unsigned long entry) |
2232 | { | |
2233 | struct kprobe_blacklist_entry *ent; | |
2234 | unsigned long offset = 0, size = 0; | |
2235 | ||
2236 | if (!kernel_text_address(entry) || | |
2237 | !kallsyms_lookup_size_offset(entry, &size, &offset)) | |
2238 | return -EINVAL; | |
2239 | ||
2240 | ent = kmalloc(sizeof(*ent), GFP_KERNEL); | |
2241 | if (!ent) | |
2242 | return -ENOMEM; | |
2243 | ent->start_addr = entry; | |
2244 | ent->end_addr = entry + size; | |
2245 | INIT_LIST_HEAD(&ent->list); | |
2246 | list_add_tail(&ent->list, &kprobe_blacklist); | |
2247 | ||
2248 | return (int)size; | |
2249 | } | |
2250 | ||
2251 | /* Add all symbols in given area into kprobe blacklist */ | |
2252 | int kprobe_add_area_blacklist(unsigned long start, unsigned long end) | |
2253 | { | |
2254 | unsigned long entry; | |
2255 | int ret = 0; | |
2256 | ||
2257 | for (entry = start; entry < end; entry += ret) { | |
2258 | ret = kprobe_add_ksym_blacklist(entry); | |
2259 | if (ret < 0) | |
2260 | return ret; | |
2261 | if (ret == 0) /* In case of alias symbol */ | |
2262 | ret = 1; | |
2263 | } | |
2264 | return 0; | |
2265 | } | |
2266 | ||
1e6769b0 MH |
2267 | /* Remove all symbols in given area from kprobe blacklist */ |
2268 | static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) | |
2269 | { | |
2270 | struct kprobe_blacklist_entry *ent, *n; | |
2271 | ||
2272 | list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { | |
2273 | if (ent->start_addr < start || ent->start_addr >= end) | |
2274 | continue; | |
2275 | list_del(&ent->list); | |
2276 | kfree(ent); | |
2277 | } | |
2278 | } | |
2279 | ||
16db6264 MH |
2280 | static void kprobe_remove_ksym_blacklist(unsigned long entry) |
2281 | { | |
2282 | kprobe_remove_area_blacklist(entry, entry + 1); | |
2283 | } | |
2284 | ||
d002b8bc AH |
2285 | int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, |
2286 | char *type, char *sym) | |
2287 | { | |
2288 | return -ERANGE; | |
2289 | } | |
2290 | ||
2291 | int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, | |
2292 | char *sym) | |
2293 | { | |
2294 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT | |
2295 | if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym)) | |
2296 | return 0; | |
2297 | #ifdef CONFIG_OPTPROBES | |
2298 | if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym)) | |
2299 | return 0; | |
2300 | #endif | |
2301 | #endif | |
2302 | if (!arch_kprobe_get_kallsym(&symnum, value, type, sym)) | |
2303 | return 0; | |
2304 | return -ERANGE; | |
2305 | } | |
2306 | ||
fb1a59fa MH |
2307 | int __init __weak arch_populate_kprobe_blacklist(void) |
2308 | { | |
2309 | return 0; | |
2310 | } | |
2311 | ||
376e2424 MH |
2312 | /* |
2313 | * Lookup and populate the kprobe_blacklist. | |
2314 | * | |
2315 | * Unlike the kretprobe blacklist, we'll need to determine | |
2316 | * the range of addresses that belong to the said functions, | |
2317 | * since a kprobe need not necessarily be at the beginning | |
2318 | * of a function. | |
2319 | */ | |
2320 | static int __init populate_kprobe_blacklist(unsigned long *start, | |
2321 | unsigned long *end) | |
2322 | { | |
fb1a59fa | 2323 | unsigned long entry; |
376e2424 | 2324 | unsigned long *iter; |
fb1a59fa | 2325 | int ret; |
376e2424 MH |
2326 | |
2327 | for (iter = start; iter < end; iter++) { | |
d81b4253 | 2328 | entry = arch_deref_entry_point((void *)*iter); |
fb1a59fa MH |
2329 | ret = kprobe_add_ksym_blacklist(entry); |
2330 | if (ret == -EINVAL) | |
376e2424 | 2331 | continue; |
fb1a59fa MH |
2332 | if (ret < 0) |
2333 | return ret; | |
376e2424 | 2334 | } |
fb1a59fa MH |
2335 | |
2336 | /* Symbols in __kprobes_text are blacklisted */ | |
2337 | ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, | |
2338 | (unsigned long)__kprobes_text_end); | |
66e9b071 TG |
2339 | if (ret) |
2340 | return ret; | |
2341 | ||
2342 | /* Symbols in noinstr section are blacklisted */ | |
2343 | ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start, | |
2344 | (unsigned long)__noinstr_text_end); | |
fb1a59fa MH |
2345 | |
2346 | return ret ? : arch_populate_kprobe_blacklist(); | |
376e2424 MH |
2347 | } |
2348 | ||
1e6769b0 MH |
2349 | static void add_module_kprobe_blacklist(struct module *mod) |
2350 | { | |
2351 | unsigned long start, end; | |
16db6264 MH |
2352 | int i; |
2353 | ||
2354 | if (mod->kprobe_blacklist) { | |
2355 | for (i = 0; i < mod->num_kprobe_blacklist; i++) | |
2356 | kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]); | |
2357 | } | |
1e6769b0 MH |
2358 | |
2359 | start = (unsigned long)mod->kprobes_text_start; | |
2360 | if (start) { | |
2361 | end = start + mod->kprobes_text_size; | |
2362 | kprobe_add_area_blacklist(start, end); | |
2363 | } | |
66e9b071 TG |
2364 | |
2365 | start = (unsigned long)mod->noinstr_text_start; | |
2366 | if (start) { | |
2367 | end = start + mod->noinstr_text_size; | |
2368 | kprobe_add_area_blacklist(start, end); | |
2369 | } | |
1e6769b0 MH |
2370 | } |
2371 | ||
2372 | static void remove_module_kprobe_blacklist(struct module *mod) | |
2373 | { | |
2374 | unsigned long start, end; | |
16db6264 MH |
2375 | int i; |
2376 | ||
2377 | if (mod->kprobe_blacklist) { | |
2378 | for (i = 0; i < mod->num_kprobe_blacklist; i++) | |
2379 | kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]); | |
2380 | } | |
1e6769b0 MH |
2381 | |
2382 | start = (unsigned long)mod->kprobes_text_start; | |
2383 | if (start) { | |
2384 | end = start + mod->kprobes_text_size; | |
2385 | kprobe_remove_area_blacklist(start, end); | |
2386 | } | |
66e9b071 TG |
2387 | |
2388 | start = (unsigned long)mod->noinstr_text_start; | |
2389 | if (start) { | |
2390 | end = start + mod->noinstr_text_size; | |
2391 | kprobe_remove_area_blacklist(start, end); | |
2392 | } | |
1e6769b0 MH |
2393 | } |
2394 | ||
e8386a0c | 2395 | /* Module notifier call back, checking kprobes on the module */ |
55479f64 MH |
2396 | static int kprobes_module_callback(struct notifier_block *nb, |
2397 | unsigned long val, void *data) | |
e8386a0c MH |
2398 | { |
2399 | struct module *mod = data; | |
2400 | struct hlist_head *head; | |
e8386a0c MH |
2401 | struct kprobe *p; |
2402 | unsigned int i; | |
f24659d9 | 2403 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2404 | |
1e6769b0 MH |
2405 | if (val == MODULE_STATE_COMING) { |
2406 | mutex_lock(&kprobe_mutex); | |
2407 | add_module_kprobe_blacklist(mod); | |
2408 | mutex_unlock(&kprobe_mutex); | |
2409 | } | |
f24659d9 | 2410 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2411 | return NOTIFY_DONE; |
2412 | ||
2413 | /* | |
f24659d9 MH |
2414 | * When MODULE_STATE_GOING was notified, both of module .text and |
2415 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
2416 | * notified, only .init.text section would be freed. We need to | |
2417 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
2418 | */ |
2419 | mutex_lock(&kprobe_mutex); | |
2420 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2421 | head = &kprobe_table[i]; | |
7e6a71d8 | 2422 | hlist_for_each_entry(p, head, hlist) |
f24659d9 MH |
2423 | if (within_module_init((unsigned long)p->addr, mod) || |
2424 | (checkcore && | |
2425 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2426 | /* |
2427 | * The vaddr this probe is installed will soon | |
2428 | * be vfreed buy not synced to disk. Hence, | |
2429 | * disarming the breakpoint isn't needed. | |
545a0281 SRV |
2430 | * |
2431 | * Note, this will also move any optimized probes | |
2432 | * that are pending to be removed from their | |
2433 | * corresponding lists to the freeing_list and | |
2434 | * will not be touched by the delayed | |
2435 | * kprobe_optimizer work handler. | |
e8386a0c MH |
2436 | */ |
2437 | kill_kprobe(p); | |
2438 | } | |
2439 | } | |
1e6769b0 MH |
2440 | if (val == MODULE_STATE_GOING) |
2441 | remove_module_kprobe_blacklist(mod); | |
e8386a0c MH |
2442 | mutex_unlock(&kprobe_mutex); |
2443 | return NOTIFY_DONE; | |
2444 | } | |
2445 | ||
2446 | static struct notifier_block kprobe_module_nb = { | |
2447 | .notifier_call = kprobes_module_callback, | |
2448 | .priority = 0 | |
2449 | }; | |
2450 | ||
376e2424 MH |
2451 | /* Markers of _kprobe_blacklist section */ |
2452 | extern unsigned long __start_kprobe_blacklist[]; | |
2453 | extern unsigned long __stop_kprobe_blacklist[]; | |
2454 | ||
1da177e4 LT |
2455 | static int __init init_kprobes(void) |
2456 | { | |
2457 | int i, err = 0; | |
2458 | ||
2459 | /* FIXME allocate the probe table, currently defined statically */ | |
2460 | /* initialize all list heads */ | |
b94cce92 | 2461 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 2462 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 2463 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ec484608 | 2464 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 2465 | } |
1da177e4 | 2466 | |
376e2424 MH |
2467 | err = populate_kprobe_blacklist(__start_kprobe_blacklist, |
2468 | __stop_kprobe_blacklist); | |
2469 | if (err) { | |
2470 | pr_err("kprobes: failed to populate blacklist: %d\n", err); | |
2471 | pr_err("Please take care of using kprobes.\n"); | |
3d8d996e SD |
2472 | } |
2473 | ||
f438d914 MH |
2474 | if (kretprobe_blacklist_size) { |
2475 | /* lookup the function address from its name */ | |
2476 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
49e0b465 | 2477 | kretprobe_blacklist[i].addr = |
290e3070 | 2478 | kprobe_lookup_name(kretprobe_blacklist[i].name, 0); |
f438d914 MH |
2479 | if (!kretprobe_blacklist[i].addr) |
2480 | printk("kretprobe: lookup failed: %s\n", | |
2481 | kretprobe_blacklist[i].name); | |
2482 | } | |
2483 | } | |
2484 | ||
b2be84df MH |
2485 | #if defined(CONFIG_OPTPROBES) |
2486 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) | |
afd66255 MH |
2487 | /* Init kprobe_optinsn_slots */ |
2488 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
2489 | #endif | |
b2be84df MH |
2490 | /* By default, kprobes can be optimized */ |
2491 | kprobes_allow_optimization = true; | |
2492 | #endif | |
afd66255 | 2493 | |
e579abeb MH |
2494 | /* By default, kprobes are armed */ |
2495 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2496 | |
6772926b | 2497 | err = arch_init_kprobes(); |
802eae7c RL |
2498 | if (!err) |
2499 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
2500 | if (!err) |
2501 | err = register_module_notifier(&kprobe_module_nb); | |
2502 | ||
ef53d9c5 | 2503 | kprobes_initialized = (err == 0); |
802eae7c | 2504 | |
8c1c9356 AM |
2505 | if (!err) |
2506 | init_test_probes(); | |
1da177e4 LT |
2507 | return err; |
2508 | } | |
65fc965c | 2509 | subsys_initcall(init_kprobes); |
1da177e4 | 2510 | |
346fd59b | 2511 | #ifdef CONFIG_DEBUG_FS |
55479f64 | 2512 | static void report_probe(struct seq_file *pi, struct kprobe *p, |
afd66255 | 2513 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2514 | { |
2515 | char *kprobe_type; | |
81365a94 | 2516 | void *addr = p->addr; |
346fd59b SD |
2517 | |
2518 | if (p->pre_handler == pre_handler_kretprobe) | |
2519 | kprobe_type = "r"; | |
346fd59b SD |
2520 | else |
2521 | kprobe_type = "k"; | |
afd66255 | 2522 | |
60f7bb66 | 2523 | if (!kallsyms_show_value(pi->file->f_cred)) |
81365a94 MH |
2524 | addr = NULL; |
2525 | ||
346fd59b | 2526 | if (sym) |
81365a94 MH |
2527 | seq_printf(pi, "%px %s %s+0x%x %s ", |
2528 | addr, kprobe_type, sym, offset, | |
afd66255 | 2529 | (modname ? modname : " ")); |
81365a94 MH |
2530 | else /* try to use %pS */ |
2531 | seq_printf(pi, "%px %s %pS ", | |
2532 | addr, kprobe_type, p->addr); | |
afd66255 MH |
2533 | |
2534 | if (!pp) | |
2535 | pp = p; | |
ae6aa16f | 2536 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2537 | (kprobe_gone(p) ? "[GONE]" : ""), |
2538 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2539 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2540 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2541 | } |
2542 | ||
55479f64 | 2543 | static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
346fd59b SD |
2544 | { |
2545 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2546 | } | |
2547 | ||
55479f64 | 2548 | static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
346fd59b SD |
2549 | { |
2550 | (*pos)++; | |
2551 | if (*pos >= KPROBE_TABLE_SIZE) | |
2552 | return NULL; | |
2553 | return pos; | |
2554 | } | |
2555 | ||
55479f64 | 2556 | static void kprobe_seq_stop(struct seq_file *f, void *v) |
346fd59b SD |
2557 | { |
2558 | /* Nothing to do */ | |
2559 | } | |
2560 | ||
55479f64 | 2561 | static int show_kprobe_addr(struct seq_file *pi, void *v) |
346fd59b SD |
2562 | { |
2563 | struct hlist_head *head; | |
346fd59b SD |
2564 | struct kprobe *p, *kp; |
2565 | const char *sym = NULL; | |
2566 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 2567 | unsigned long offset = 0; |
ab767865 | 2568 | char *modname, namebuf[KSYM_NAME_LEN]; |
346fd59b SD |
2569 | |
2570 | head = &kprobe_table[i]; | |
2571 | preempt_disable(); | |
b67bfe0d | 2572 | hlist_for_each_entry_rcu(p, head, hlist) { |
ffb45122 | 2573 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2574 | &offset, &modname, namebuf); |
afd66255 | 2575 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2576 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2577 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2578 | } else |
afd66255 | 2579 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2580 | } |
2581 | preempt_enable(); | |
2582 | return 0; | |
2583 | } | |
2584 | ||
eac2cece | 2585 | static const struct seq_operations kprobes_sops = { |
346fd59b SD |
2586 | .start = kprobe_seq_start, |
2587 | .next = kprobe_seq_next, | |
2588 | .stop = kprobe_seq_stop, | |
2589 | .show = show_kprobe_addr | |
2590 | }; | |
2591 | ||
eac2cece | 2592 | DEFINE_SEQ_ATTRIBUTE(kprobes); |
346fd59b | 2593 | |
63724740 MH |
2594 | /* kprobes/blacklist -- shows which functions can not be probed */ |
2595 | static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) | |
2596 | { | |
4fdd8887 | 2597 | mutex_lock(&kprobe_mutex); |
63724740 MH |
2598 | return seq_list_start(&kprobe_blacklist, *pos); |
2599 | } | |
2600 | ||
2601 | static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
2602 | { | |
2603 | return seq_list_next(v, &kprobe_blacklist, pos); | |
2604 | } | |
2605 | ||
2606 | static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) | |
2607 | { | |
2608 | struct kprobe_blacklist_entry *ent = | |
2609 | list_entry(v, struct kprobe_blacklist_entry, list); | |
2610 | ||
ffb9bd68 MH |
2611 | /* |
2612 | * If /proc/kallsyms is not showing kernel address, we won't | |
2613 | * show them here either. | |
2614 | */ | |
60f7bb66 | 2615 | if (!kallsyms_show_value(m->file->f_cred)) |
ffb9bd68 MH |
2616 | seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL, |
2617 | (void *)ent->start_addr); | |
2618 | else | |
2619 | seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr, | |
2620 | (void *)ent->end_addr, (void *)ent->start_addr); | |
63724740 MH |
2621 | return 0; |
2622 | } | |
2623 | ||
4fdd8887 MH |
2624 | static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v) |
2625 | { | |
2626 | mutex_unlock(&kprobe_mutex); | |
2627 | } | |
2628 | ||
eac2cece | 2629 | static const struct seq_operations kprobe_blacklist_sops = { |
63724740 MH |
2630 | .start = kprobe_blacklist_seq_start, |
2631 | .next = kprobe_blacklist_seq_next, | |
4fdd8887 | 2632 | .stop = kprobe_blacklist_seq_stop, |
63724740 MH |
2633 | .show = kprobe_blacklist_seq_show, |
2634 | }; | |
eac2cece | 2635 | DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist); |
63724740 | 2636 | |
12310e34 | 2637 | static int arm_all_kprobes(void) |
bf8f6e5b AM |
2638 | { |
2639 | struct hlist_head *head; | |
bf8f6e5b | 2640 | struct kprobe *p; |
12310e34 JY |
2641 | unsigned int i, total = 0, errors = 0; |
2642 | int err, ret = 0; | |
bf8f6e5b AM |
2643 | |
2644 | mutex_lock(&kprobe_mutex); | |
2645 | ||
e579abeb MH |
2646 | /* If kprobes are armed, just return */ |
2647 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2648 | goto already_enabled; |
2649 | ||
977ad481 WN |
2650 | /* |
2651 | * optimize_kprobe() called by arm_kprobe() checks | |
2652 | * kprobes_all_disarmed, so set kprobes_all_disarmed before | |
2653 | * arm_kprobe. | |
2654 | */ | |
2655 | kprobes_all_disarmed = false; | |
afd66255 | 2656 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2657 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2658 | head = &kprobe_table[i]; | |
12310e34 | 2659 | /* Arm all kprobes on a best-effort basis */ |
7e6a71d8 | 2660 | hlist_for_each_entry(p, head, hlist) { |
12310e34 JY |
2661 | if (!kprobe_disabled(p)) { |
2662 | err = arm_kprobe(p); | |
2663 | if (err) { | |
2664 | errors++; | |
2665 | ret = err; | |
2666 | } | |
2667 | total++; | |
2668 | } | |
2669 | } | |
bf8f6e5b AM |
2670 | } |
2671 | ||
12310e34 JY |
2672 | if (errors) |
2673 | pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n", | |
2674 | errors, total); | |
2675 | else | |
2676 | pr_info("Kprobes globally enabled\n"); | |
bf8f6e5b AM |
2677 | |
2678 | already_enabled: | |
2679 | mutex_unlock(&kprobe_mutex); | |
12310e34 | 2680 | return ret; |
bf8f6e5b AM |
2681 | } |
2682 | ||
297f9233 | 2683 | static int disarm_all_kprobes(void) |
bf8f6e5b AM |
2684 | { |
2685 | struct hlist_head *head; | |
bf8f6e5b | 2686 | struct kprobe *p; |
297f9233 JY |
2687 | unsigned int i, total = 0, errors = 0; |
2688 | int err, ret = 0; | |
bf8f6e5b AM |
2689 | |
2690 | mutex_lock(&kprobe_mutex); | |
2691 | ||
e579abeb | 2692 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2693 | if (kprobes_all_disarmed) { |
2694 | mutex_unlock(&kprobe_mutex); | |
297f9233 | 2695 | return 0; |
6274de49 | 2696 | } |
bf8f6e5b | 2697 | |
e579abeb | 2698 | kprobes_all_disarmed = true; |
afd66255 | 2699 | |
bf8f6e5b AM |
2700 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2701 | head = &kprobe_table[i]; | |
297f9233 | 2702 | /* Disarm all kprobes on a best-effort basis */ |
7e6a71d8 | 2703 | hlist_for_each_entry(p, head, hlist) { |
297f9233 JY |
2704 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) { |
2705 | err = disarm_kprobe(p, false); | |
2706 | if (err) { | |
2707 | errors++; | |
2708 | ret = err; | |
2709 | } | |
2710 | total++; | |
2711 | } | |
bf8f6e5b AM |
2712 | } |
2713 | } | |
297f9233 JY |
2714 | |
2715 | if (errors) | |
2716 | pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n", | |
2717 | errors, total); | |
2718 | else | |
2719 | pr_info("Kprobes globally disabled\n"); | |
2720 | ||
bf8f6e5b | 2721 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2722 | |
6274de49 MH |
2723 | /* Wait for disarming all kprobes by optimizer */ |
2724 | wait_for_kprobe_optimizer(); | |
297f9233 JY |
2725 | |
2726 | return ret; | |
bf8f6e5b AM |
2727 | } |
2728 | ||
2729 | /* | |
2730 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2731 | * when the bool state is switched. We can reuse that facility when | |
2732 | * available | |
2733 | */ | |
2734 | static ssize_t read_enabled_file_bool(struct file *file, | |
2735 | char __user *user_buf, size_t count, loff_t *ppos) | |
2736 | { | |
2737 | char buf[3]; | |
2738 | ||
e579abeb | 2739 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
2740 | buf[0] = '1'; |
2741 | else | |
2742 | buf[0] = '0'; | |
2743 | buf[1] = '\n'; | |
2744 | buf[2] = 0x00; | |
2745 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2746 | } | |
2747 | ||
2748 | static ssize_t write_enabled_file_bool(struct file *file, | |
2749 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2750 | { | |
2751 | char buf[32]; | |
efeb156e | 2752 | size_t buf_size; |
12310e34 | 2753 | int ret = 0; |
bf8f6e5b AM |
2754 | |
2755 | buf_size = min(count, (sizeof(buf)-1)); | |
2756 | if (copy_from_user(buf, user_buf, buf_size)) | |
2757 | return -EFAULT; | |
2758 | ||
10fb46d5 | 2759 | buf[buf_size] = '\0'; |
bf8f6e5b AM |
2760 | switch (buf[0]) { |
2761 | case 'y': | |
2762 | case 'Y': | |
2763 | case '1': | |
12310e34 | 2764 | ret = arm_all_kprobes(); |
bf8f6e5b AM |
2765 | break; |
2766 | case 'n': | |
2767 | case 'N': | |
2768 | case '0': | |
297f9233 | 2769 | ret = disarm_all_kprobes(); |
bf8f6e5b | 2770 | break; |
10fb46d5 MK |
2771 | default: |
2772 | return -EINVAL; | |
bf8f6e5b AM |
2773 | } |
2774 | ||
12310e34 JY |
2775 | if (ret) |
2776 | return ret; | |
2777 | ||
bf8f6e5b AM |
2778 | return count; |
2779 | } | |
2780 | ||
828c0950 | 2781 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2782 | .read = read_enabled_file_bool, |
2783 | .write = write_enabled_file_bool, | |
6038f373 | 2784 | .llseek = default_llseek, |
bf8f6e5b AM |
2785 | }; |
2786 | ||
55479f64 | 2787 | static int __init debugfs_kprobe_init(void) |
346fd59b | 2788 | { |
8c0fd1fa | 2789 | struct dentry *dir; |
bf8f6e5b | 2790 | unsigned int value = 1; |
346fd59b SD |
2791 | |
2792 | dir = debugfs_create_dir("kprobes", NULL); | |
346fd59b | 2793 | |
eac2cece | 2794 | debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops); |
346fd59b | 2795 | |
8c0fd1fa | 2796 | debugfs_create_file("enabled", 0600, dir, &value, &fops_kp); |
63724740 | 2797 | |
8c0fd1fa | 2798 | debugfs_create_file("blacklist", 0400, dir, NULL, |
eac2cece | 2799 | &kprobe_blacklist_fops); |
bf8f6e5b | 2800 | |
346fd59b SD |
2801 | return 0; |
2802 | } | |
2803 | ||
2804 | late_initcall(debugfs_kprobe_init); | |
2805 | #endif /* CONFIG_DEBUG_FS */ |