Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Kernel Probes (KProbes) | |
3 | * kernel/kprobes.c | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
18 | * | |
19 | * Copyright (C) IBM Corporation, 2002, 2004 | |
20 | * | |
21 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel | |
22 | * Probes initial implementation (includes suggestions from | |
23 | * Rusty Russell). | |
24 | * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with | |
25 | * hlists and exceptions notifier as suggested by Andi Kleen. | |
26 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes | |
27 | * interface to access function arguments. | |
28 | * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes | |
29 | * exceptions notifier to be first on the priority list. | |
b94cce92 HN |
30 | * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston |
31 | * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi | |
32 | * <prasanna@in.ibm.com> added function-return probes. | |
1da177e4 LT |
33 | */ |
34 | #include <linux/kprobes.h> | |
1da177e4 LT |
35 | #include <linux/hash.h> |
36 | #include <linux/init.h> | |
4e57b681 | 37 | #include <linux/slab.h> |
e3869792 | 38 | #include <linux/stddef.h> |
9984de1a | 39 | #include <linux/export.h> |
9ec4b1f3 | 40 | #include <linux/moduleloader.h> |
3a872d89 | 41 | #include <linux/kallsyms.h> |
b4c6c34a | 42 | #include <linux/freezer.h> |
346fd59b SD |
43 | #include <linux/seq_file.h> |
44 | #include <linux/debugfs.h> | |
b2be84df | 45 | #include <linux/sysctl.h> |
1eeb66a1 | 46 | #include <linux/kdebug.h> |
4460fdad | 47 | #include <linux/memory.h> |
4554dbcb | 48 | #include <linux/ftrace.h> |
afd66255 | 49 | #include <linux/cpu.h> |
bf5438fc | 50 | #include <linux/jump_label.h> |
bf8f6e5b | 51 | |
d0aaff97 | 52 | #include <asm-generic/sections.h> |
1da177e4 LT |
53 | #include <asm/cacheflush.h> |
54 | #include <asm/errno.h> | |
bf8f6e5b | 55 | #include <asm/uaccess.h> |
1da177e4 LT |
56 | |
57 | #define KPROBE_HASH_BITS 6 | |
58 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
59 | ||
3a872d89 AM |
60 | |
61 | /* | |
62 | * Some oddball architectures like 64bit powerpc have function descriptors | |
63 | * so this must be overridable. | |
64 | */ | |
65 | #ifndef kprobe_lookup_name | |
66 | #define kprobe_lookup_name(name, addr) \ | |
67 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) | |
68 | #endif | |
69 | ||
ef53d9c5 | 70 | static int kprobes_initialized; |
1da177e4 | 71 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 72 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 73 | |
bf8f6e5b | 74 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 75 | static bool kprobes_all_disarmed; |
bf8f6e5b | 76 | |
43948f50 MH |
77 | /* This protects kprobe_table and optimizing_list */ |
78 | static DEFINE_MUTEX(kprobe_mutex); | |
e6584523 | 79 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 80 | static struct { |
ec484608 | 81 | raw_spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
82 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
83 | ||
ec484608 | 84 | static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
ef53d9c5 S |
85 | { |
86 | return &(kretprobe_table_locks[hash].lock); | |
87 | } | |
1da177e4 | 88 | |
3d8d996e SD |
89 | /* |
90 | * Normally, functions that we'd want to prohibit kprobes in, are marked | |
91 | * __kprobes. But, there are cases where such functions already belong to | |
92 | * a different section (__sched for preempt_schedule) | |
93 | * | |
94 | * For such cases, we now have a blacklist | |
95 | */ | |
544304b2 | 96 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
3d8d996e | 97 | {"preempt_schedule",}, |
65e234ec | 98 | {"native_get_debugreg",}, |
a00e817f MH |
99 | {"irq_entries_start",}, |
100 | {"common_interrupt",}, | |
5ecaafdb | 101 | {"mcount",}, /* mcount can be called from everywhere */ |
3d8d996e SD |
102 | {NULL} /* Terminator */ |
103 | }; | |
104 | ||
2d14e39d | 105 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
106 | /* |
107 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
108 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
109 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
110 | * is a recipe for disaster | |
111 | */ | |
9ec4b1f3 | 112 | struct kprobe_insn_page { |
c5cb5a2d | 113 | struct list_head list; |
9ec4b1f3 | 114 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
9ec4b1f3 | 115 | int nused; |
b4c6c34a | 116 | int ngarbage; |
4610ee1d | 117 | char slot_used[]; |
9ec4b1f3 AM |
118 | }; |
119 | ||
4610ee1d MH |
120 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
121 | (offsetof(struct kprobe_insn_page, slot_used) + \ | |
122 | (sizeof(char) * (slots))) | |
123 | ||
124 | struct kprobe_insn_cache { | |
125 | struct list_head pages; /* list of kprobe_insn_page */ | |
126 | size_t insn_size; /* size of instruction slot */ | |
127 | int nr_garbage; | |
128 | }; | |
129 | ||
130 | static int slots_per_page(struct kprobe_insn_cache *c) | |
131 | { | |
132 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
133 | } | |
134 | ||
ab40c5c6 MH |
135 | enum kprobe_slot_state { |
136 | SLOT_CLEAN = 0, | |
137 | SLOT_DIRTY = 1, | |
138 | SLOT_USED = 2, | |
139 | }; | |
140 | ||
4610ee1d MH |
141 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ |
142 | static struct kprobe_insn_cache kprobe_insn_slots = { | |
143 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), | |
144 | .insn_size = MAX_INSN_SIZE, | |
145 | .nr_garbage = 0, | |
146 | }; | |
147 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); | |
b4c6c34a | 148 | |
9ec4b1f3 | 149 | /** |
12941560 | 150 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
151 | * We allocate an executable page if there's no room on existing ones. |
152 | */ | |
4610ee1d | 153 | static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
154 | { |
155 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 156 | |
6f716acd | 157 | retry: |
4610ee1d MH |
158 | list_for_each_entry(kip, &c->pages, list) { |
159 | if (kip->nused < slots_per_page(c)) { | |
9ec4b1f3 | 160 | int i; |
4610ee1d | 161 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
162 | if (kip->slot_used[i] == SLOT_CLEAN) { |
163 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 164 | kip->nused++; |
4610ee1d | 165 | return kip->insns + (i * c->insn_size); |
9ec4b1f3 AM |
166 | } |
167 | } | |
4610ee1d MH |
168 | /* kip->nused is broken. Fix it. */ |
169 | kip->nused = slots_per_page(c); | |
170 | WARN_ON(1); | |
9ec4b1f3 AM |
171 | } |
172 | } | |
173 | ||
b4c6c34a | 174 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 175 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 176 | goto retry; |
4610ee1d MH |
177 | |
178 | /* All out of space. Need to allocate a new page. */ | |
179 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); | |
6f716acd | 180 | if (!kip) |
9ec4b1f3 | 181 | return NULL; |
9ec4b1f3 AM |
182 | |
183 | /* | |
184 | * Use module_alloc so this page is within +/- 2GB of where the | |
185 | * kernel image and loaded module images reside. This is required | |
186 | * so x86_64 can correctly handle the %rip-relative fixups. | |
187 | */ | |
188 | kip->insns = module_alloc(PAGE_SIZE); | |
189 | if (!kip->insns) { | |
190 | kfree(kip); | |
191 | return NULL; | |
192 | } | |
c5cb5a2d | 193 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 194 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 195 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 196 | kip->nused = 1; |
b4c6c34a | 197 | kip->ngarbage = 0; |
4610ee1d | 198 | list_add(&kip->list, &c->pages); |
9ec4b1f3 AM |
199 | return kip->insns; |
200 | } | |
201 | ||
4610ee1d | 202 | |
12941560 MH |
203 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
204 | { | |
4610ee1d MH |
205 | kprobe_opcode_t *ret = NULL; |
206 | ||
12941560 | 207 | mutex_lock(&kprobe_insn_mutex); |
4610ee1d | 208 | ret = __get_insn_slot(&kprobe_insn_slots); |
12941560 | 209 | mutex_unlock(&kprobe_insn_mutex); |
4610ee1d | 210 | |
12941560 MH |
211 | return ret; |
212 | } | |
213 | ||
b4c6c34a MH |
214 | /* Return 1 if all garbages are collected, otherwise 0. */ |
215 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
216 | { | |
ab40c5c6 | 217 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
218 | kip->nused--; |
219 | if (kip->nused == 0) { | |
220 | /* | |
221 | * Page is no longer in use. Free it unless | |
222 | * it's the last one. We keep the last one | |
223 | * so as not to have to set it up again the | |
224 | * next time somebody inserts a probe. | |
225 | */ | |
4610ee1d | 226 | if (!list_is_singular(&kip->list)) { |
c5cb5a2d | 227 | list_del(&kip->list); |
b4c6c34a MH |
228 | module_free(NULL, kip->insns); |
229 | kfree(kip); | |
230 | } | |
231 | return 1; | |
232 | } | |
233 | return 0; | |
234 | } | |
235 | ||
4610ee1d | 236 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 237 | { |
c5cb5a2d | 238 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 239 | |
615d0ebb MH |
240 | /* Ensure no-one is interrupted on the garbages */ |
241 | synchronize_sched(); | |
b4c6c34a | 242 | |
4610ee1d | 243 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 244 | int i; |
b4c6c34a MH |
245 | if (kip->ngarbage == 0) |
246 | continue; | |
247 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 248 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 | 249 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
250 | collect_one_slot(kip, i)) |
251 | break; | |
252 | } | |
253 | } | |
4610ee1d | 254 | c->nr_garbage = 0; |
b4c6c34a MH |
255 | return 0; |
256 | } | |
257 | ||
4610ee1d MH |
258 | static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
259 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
260 | { |
261 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 262 | |
4610ee1d | 263 | list_for_each_entry(kip, &c->pages, list) { |
83ff56f4 MH |
264 | long idx = ((long)slot - (long)kip->insns) / |
265 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
4610ee1d MH |
266 | if (idx >= 0 && idx < slots_per_page(c)) { |
267 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
b4c6c34a | 268 | if (dirty) { |
4610ee1d | 269 | kip->slot_used[idx] = SLOT_DIRTY; |
b4c6c34a | 270 | kip->ngarbage++; |
4610ee1d MH |
271 | if (++c->nr_garbage > slots_per_page(c)) |
272 | collect_garbage_slots(c); | |
c5cb5a2d | 273 | } else |
4610ee1d MH |
274 | collect_one_slot(kip, idx); |
275 | return; | |
9ec4b1f3 AM |
276 | } |
277 | } | |
4610ee1d MH |
278 | /* Could not free this slot. */ |
279 | WARN_ON(1); | |
280 | } | |
6f716acd | 281 | |
4610ee1d MH |
282 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
283 | { | |
284 | mutex_lock(&kprobe_insn_mutex); | |
285 | __free_insn_slot(&kprobe_insn_slots, slot, dirty); | |
12941560 | 286 | mutex_unlock(&kprobe_insn_mutex); |
9ec4b1f3 | 287 | } |
afd66255 MH |
288 | #ifdef CONFIG_OPTPROBES |
289 | /* For optimized_kprobe buffer */ | |
290 | static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ | |
291 | static struct kprobe_insn_cache kprobe_optinsn_slots = { | |
292 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), | |
293 | /* .insn_size is initialized later */ | |
294 | .nr_garbage = 0, | |
295 | }; | |
296 | /* Get a slot for optimized_kprobe buffer */ | |
297 | kprobe_opcode_t __kprobes *get_optinsn_slot(void) | |
298 | { | |
299 | kprobe_opcode_t *ret = NULL; | |
300 | ||
301 | mutex_lock(&kprobe_optinsn_mutex); | |
302 | ret = __get_insn_slot(&kprobe_optinsn_slots); | |
303 | mutex_unlock(&kprobe_optinsn_mutex); | |
304 | ||
305 | return ret; | |
306 | } | |
307 | ||
308 | void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) | |
309 | { | |
310 | mutex_lock(&kprobe_optinsn_mutex); | |
311 | __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); | |
312 | mutex_unlock(&kprobe_optinsn_mutex); | |
313 | } | |
314 | #endif | |
2d14e39d | 315 | #endif |
9ec4b1f3 | 316 | |
e6584523 AM |
317 | /* We have preemption disabled.. so it is safe to use __ versions */ |
318 | static inline void set_kprobe_instance(struct kprobe *kp) | |
319 | { | |
b76834bc | 320 | __this_cpu_write(kprobe_instance, kp); |
e6584523 AM |
321 | } |
322 | ||
323 | static inline void reset_kprobe_instance(void) | |
324 | { | |
b76834bc | 325 | __this_cpu_write(kprobe_instance, NULL); |
e6584523 AM |
326 | } |
327 | ||
3516a460 AM |
328 | /* |
329 | * This routine is called either: | |
49a2a1b8 | 330 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 331 | * OR |
d217d545 | 332 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 333 | */ |
d0aaff97 | 334 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
335 | { |
336 | struct hlist_head *head; | |
337 | struct hlist_node *node; | |
3516a460 | 338 | struct kprobe *p; |
1da177e4 LT |
339 | |
340 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 341 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
342 | if (p->addr == addr) |
343 | return p; | |
344 | } | |
afd66255 | 345 | |
1da177e4 LT |
346 | return NULL; |
347 | } | |
348 | ||
afd66255 MH |
349 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
350 | ||
351 | /* Return true if the kprobe is an aggregator */ | |
352 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
353 | { | |
354 | return p->pre_handler == aggr_pre_handler; | |
355 | } | |
356 | ||
6274de49 MH |
357 | /* Return true(!0) if the kprobe is unused */ |
358 | static inline int kprobe_unused(struct kprobe *p) | |
359 | { | |
360 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && | |
361 | list_empty(&p->list); | |
362 | } | |
363 | ||
afd66255 MH |
364 | /* |
365 | * Keep all fields in the kprobe consistent | |
366 | */ | |
6d8e40a8 | 367 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 368 | { |
6d8e40a8 MH |
369 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
370 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
371 | } |
372 | ||
373 | #ifdef CONFIG_OPTPROBES | |
b2be84df MH |
374 | /* NOTE: change this value only with kprobe_mutex held */ |
375 | static bool kprobes_allow_optimization; | |
376 | ||
afd66255 MH |
377 | /* |
378 | * Call all pre_handler on the list, but ignores its return value. | |
379 | * This must be called from arch-dep optimized caller. | |
380 | */ | |
381 | void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
382 | { | |
383 | struct kprobe *kp; | |
384 | ||
385 | list_for_each_entry_rcu(kp, &p->list, list) { | |
386 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
387 | set_kprobe_instance(kp); | |
388 | kp->pre_handler(kp, regs); | |
389 | } | |
390 | reset_kprobe_instance(); | |
391 | } | |
392 | } | |
393 | ||
6274de49 MH |
394 | /* Free optimized instructions and optimized_kprobe */ |
395 | static __kprobes void free_aggr_kprobe(struct kprobe *p) | |
396 | { | |
397 | struct optimized_kprobe *op; | |
398 | ||
399 | op = container_of(p, struct optimized_kprobe, kp); | |
400 | arch_remove_optimized_kprobe(op); | |
401 | arch_remove_kprobe(p); | |
402 | kfree(op); | |
403 | } | |
404 | ||
afd66255 MH |
405 | /* Return true(!0) if the kprobe is ready for optimization. */ |
406 | static inline int kprobe_optready(struct kprobe *p) | |
407 | { | |
408 | struct optimized_kprobe *op; | |
409 | ||
410 | if (kprobe_aggrprobe(p)) { | |
411 | op = container_of(p, struct optimized_kprobe, kp); | |
412 | return arch_prepared_optinsn(&op->optinsn); | |
413 | } | |
414 | ||
415 | return 0; | |
416 | } | |
417 | ||
6274de49 MH |
418 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
419 | static inline int kprobe_disarmed(struct kprobe *p) | |
420 | { | |
421 | struct optimized_kprobe *op; | |
422 | ||
423 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ | |
424 | if (!kprobe_aggrprobe(p)) | |
425 | return kprobe_disabled(p); | |
426 | ||
427 | op = container_of(p, struct optimized_kprobe, kp); | |
428 | ||
429 | return kprobe_disabled(p) && list_empty(&op->list); | |
430 | } | |
431 | ||
432 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ | |
433 | static int __kprobes kprobe_queued(struct kprobe *p) | |
434 | { | |
435 | struct optimized_kprobe *op; | |
436 | ||
437 | if (kprobe_aggrprobe(p)) { | |
438 | op = container_of(p, struct optimized_kprobe, kp); | |
439 | if (!list_empty(&op->list)) | |
440 | return 1; | |
441 | } | |
442 | return 0; | |
443 | } | |
444 | ||
afd66255 MH |
445 | /* |
446 | * Return an optimized kprobe whose optimizing code replaces | |
447 | * instructions including addr (exclude breakpoint). | |
448 | */ | |
6376b229 | 449 | static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) |
afd66255 MH |
450 | { |
451 | int i; | |
452 | struct kprobe *p = NULL; | |
453 | struct optimized_kprobe *op; | |
454 | ||
455 | /* Don't check i == 0, since that is a breakpoint case. */ | |
456 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
457 | p = get_kprobe((void *)(addr - i)); | |
458 | ||
459 | if (p && kprobe_optready(p)) { | |
460 | op = container_of(p, struct optimized_kprobe, kp); | |
461 | if (arch_within_optimized_kprobe(op, addr)) | |
462 | return p; | |
463 | } | |
464 | ||
465 | return NULL; | |
466 | } | |
467 | ||
468 | /* Optimization staging list, protected by kprobe_mutex */ | |
469 | static LIST_HEAD(optimizing_list); | |
6274de49 | 470 | static LIST_HEAD(unoptimizing_list); |
afd66255 MH |
471 | |
472 | static void kprobe_optimizer(struct work_struct *work); | |
473 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
6274de49 | 474 | static DECLARE_COMPLETION(optimizer_comp); |
afd66255 MH |
475 | #define OPTIMIZE_DELAY 5 |
476 | ||
61f4e13f MH |
477 | /* |
478 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
479 | * optimizing_list. | |
480 | */ | |
481 | static __kprobes void do_optimize_kprobes(void) | |
afd66255 | 482 | { |
6274de49 MH |
483 | /* Optimization never be done when disarmed */ |
484 | if (kprobes_all_disarmed || !kprobes_allow_optimization || | |
485 | list_empty(&optimizing_list)) | |
486 | return; | |
487 | ||
afd66255 MH |
488 | /* |
489 | * The optimization/unoptimization refers online_cpus via | |
490 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
491 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
492 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
493 | * text_mutex but stop_machine can not be done because online_cpus | |
494 | * has been changed) | |
495 | * To avoid this deadlock, we need to call get_online_cpus() | |
496 | * for preventing cpu-hotplug outside of text_mutex locking. | |
497 | */ | |
498 | get_online_cpus(); | |
499 | mutex_lock(&text_mutex); | |
cd7ebe22 | 500 | arch_optimize_kprobes(&optimizing_list); |
afd66255 MH |
501 | mutex_unlock(&text_mutex); |
502 | put_online_cpus(); | |
61f4e13f MH |
503 | } |
504 | ||
6274de49 MH |
505 | /* |
506 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint | |
507 | * if need) kprobes listed on unoptimizing_list. | |
508 | */ | |
509 | static __kprobes void do_unoptimize_kprobes(struct list_head *free_list) | |
510 | { | |
511 | struct optimized_kprobe *op, *tmp; | |
512 | ||
513 | /* Unoptimization must be done anytime */ | |
514 | if (list_empty(&unoptimizing_list)) | |
515 | return; | |
516 | ||
517 | /* Ditto to do_optimize_kprobes */ | |
518 | get_online_cpus(); | |
519 | mutex_lock(&text_mutex); | |
f984ba4e MH |
520 | arch_unoptimize_kprobes(&unoptimizing_list, free_list); |
521 | /* Loop free_list for disarming */ | |
522 | list_for_each_entry_safe(op, tmp, free_list, list) { | |
6274de49 MH |
523 | /* Disarm probes if marked disabled */ |
524 | if (kprobe_disabled(&op->kp)) | |
525 | arch_disarm_kprobe(&op->kp); | |
526 | if (kprobe_unused(&op->kp)) { | |
527 | /* | |
528 | * Remove unused probes from hash list. After waiting | |
529 | * for synchronization, these probes are reclaimed. | |
530 | * (reclaiming is done by do_free_cleaned_kprobes.) | |
531 | */ | |
532 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
533 | } else |
534 | list_del_init(&op->list); | |
535 | } | |
536 | mutex_unlock(&text_mutex); | |
537 | put_online_cpus(); | |
538 | } | |
539 | ||
540 | /* Reclaim all kprobes on the free_list */ | |
541 | static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list) | |
542 | { | |
543 | struct optimized_kprobe *op, *tmp; | |
544 | ||
545 | list_for_each_entry_safe(op, tmp, free_list, list) { | |
546 | BUG_ON(!kprobe_unused(&op->kp)); | |
547 | list_del_init(&op->list); | |
548 | free_aggr_kprobe(&op->kp); | |
549 | } | |
550 | } | |
551 | ||
552 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
553 | static __kprobes void kick_kprobe_optimizer(void) | |
554 | { | |
555 | if (!delayed_work_pending(&optimizing_work)) | |
556 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); | |
557 | } | |
558 | ||
61f4e13f MH |
559 | /* Kprobe jump optimizer */ |
560 | static __kprobes void kprobe_optimizer(struct work_struct *work) | |
561 | { | |
6274de49 MH |
562 | LIST_HEAD(free_list); |
563 | ||
72ef3794 | 564 | mutex_lock(&kprobe_mutex); |
61f4e13f MH |
565 | /* Lock modules while optimizing kprobes */ |
566 | mutex_lock(&module_mutex); | |
61f4e13f MH |
567 | |
568 | /* | |
6274de49 MH |
569 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
570 | * kprobes before waiting for quiesence period. | |
571 | */ | |
572 | do_unoptimize_kprobes(&free_list); | |
573 | ||
574 | /* | |
575 | * Step 2: Wait for quiesence period to ensure all running interrupts | |
61f4e13f MH |
576 | * are done. Because optprobe may modify multiple instructions |
577 | * there is a chance that Nth instruction is interrupted. In that | |
578 | * case, running interrupt can return to 2nd-Nth byte of jump | |
579 | * instruction. This wait is for avoiding it. | |
580 | */ | |
581 | synchronize_sched(); | |
582 | ||
6274de49 | 583 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 584 | do_optimize_kprobes(); |
6274de49 MH |
585 | |
586 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
587 | do_free_cleaned_kprobes(&free_list); | |
588 | ||
afd66255 | 589 | mutex_unlock(&module_mutex); |
72ef3794 | 590 | mutex_unlock(&kprobe_mutex); |
6274de49 | 591 | |
cd7ebe22 | 592 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 593 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 MH |
594 | kick_kprobe_optimizer(); |
595 | else | |
596 | /* Wake up all waiters */ | |
597 | complete_all(&optimizer_comp); | |
6274de49 MH |
598 | } |
599 | ||
600 | /* Wait for completing optimization and unoptimization */ | |
601 | static __kprobes void wait_for_kprobe_optimizer(void) | |
602 | { | |
603 | if (delayed_work_pending(&optimizing_work)) | |
604 | wait_for_completion(&optimizer_comp); | |
afd66255 MH |
605 | } |
606 | ||
607 | /* Optimize kprobe if p is ready to be optimized */ | |
608 | static __kprobes void optimize_kprobe(struct kprobe *p) | |
609 | { | |
610 | struct optimized_kprobe *op; | |
611 | ||
612 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 613 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
614 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
615 | return; | |
616 | ||
617 | /* Both of break_handler and post_handler are not supported. */ | |
618 | if (p->break_handler || p->post_handler) | |
619 | return; | |
620 | ||
621 | op = container_of(p, struct optimized_kprobe, kp); | |
622 | ||
623 | /* Check there is no other kprobes at the optimized instructions */ | |
624 | if (arch_check_optimized_kprobe(op) < 0) | |
625 | return; | |
626 | ||
627 | /* Check if it is already optimized. */ | |
628 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) | |
629 | return; | |
afd66255 | 630 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 MH |
631 | |
632 | if (!list_empty(&op->list)) | |
633 | /* This is under unoptimizing. Just dequeue the probe */ | |
634 | list_del_init(&op->list); | |
635 | else { | |
636 | list_add(&op->list, &optimizing_list); | |
637 | kick_kprobe_optimizer(); | |
638 | } | |
639 | } | |
640 | ||
641 | /* Short cut to direct unoptimizing */ | |
642 | static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op) | |
643 | { | |
644 | get_online_cpus(); | |
645 | arch_unoptimize_kprobe(op); | |
646 | put_online_cpus(); | |
647 | if (kprobe_disabled(&op->kp)) | |
648 | arch_disarm_kprobe(&op->kp); | |
afd66255 MH |
649 | } |
650 | ||
651 | /* Unoptimize a kprobe if p is optimized */ | |
6274de49 | 652 | static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
653 | { |
654 | struct optimized_kprobe *op; | |
655 | ||
6274de49 MH |
656 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
657 | return; /* This is not an optprobe nor optimized */ | |
658 | ||
659 | op = container_of(p, struct optimized_kprobe, kp); | |
660 | if (!kprobe_optimized(p)) { | |
661 | /* Unoptimized or unoptimizing case */ | |
662 | if (force && !list_empty(&op->list)) { | |
663 | /* | |
664 | * Only if this is unoptimizing kprobe and forced, | |
665 | * forcibly unoptimize it. (No need to unoptimize | |
666 | * unoptimized kprobe again :) | |
667 | */ | |
afd66255 | 668 | list_del_init(&op->list); |
6274de49 MH |
669 | force_unoptimize_kprobe(op); |
670 | } | |
671 | return; | |
672 | } | |
673 | ||
674 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
675 | if (!list_empty(&op->list)) { | |
676 | /* Dequeue from the optimization queue */ | |
677 | list_del_init(&op->list); | |
678 | return; | |
679 | } | |
680 | /* Optimized kprobe case */ | |
681 | if (force) | |
682 | /* Forcibly update the code: this is a special case */ | |
683 | force_unoptimize_kprobe(op); | |
684 | else { | |
685 | list_add(&op->list, &unoptimizing_list); | |
686 | kick_kprobe_optimizer(); | |
afd66255 MH |
687 | } |
688 | } | |
689 | ||
0490cd1f MH |
690 | /* Cancel unoptimizing for reusing */ |
691 | static void reuse_unused_kprobe(struct kprobe *ap) | |
692 | { | |
693 | struct optimized_kprobe *op; | |
694 | ||
695 | BUG_ON(!kprobe_unused(ap)); | |
696 | /* | |
697 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
698 | * there is still a relative jump) and disabled. | |
699 | */ | |
700 | op = container_of(ap, struct optimized_kprobe, kp); | |
701 | if (unlikely(list_empty(&op->list))) | |
702 | printk(KERN_WARNING "Warning: found a stray unused " | |
703 | "aggrprobe@%p\n", ap->addr); | |
704 | /* Enable the probe again */ | |
705 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
706 | /* Optimize it again (remove from op->list) */ | |
707 | BUG_ON(!kprobe_optready(ap)); | |
708 | optimize_kprobe(ap); | |
709 | } | |
710 | ||
afd66255 MH |
711 | /* Remove optimized instructions */ |
712 | static void __kprobes kill_optimized_kprobe(struct kprobe *p) | |
713 | { | |
714 | struct optimized_kprobe *op; | |
715 | ||
716 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
717 | if (!list_empty(&op->list)) |
718 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 719 | list_del_init(&op->list); |
6274de49 MH |
720 | |
721 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
722 | /* Don't touch the code, because it is already freed. */ | |
afd66255 MH |
723 | arch_remove_optimized_kprobe(op); |
724 | } | |
725 | ||
726 | /* Try to prepare optimized instructions */ | |
727 | static __kprobes void prepare_optimized_kprobe(struct kprobe *p) | |
728 | { | |
729 | struct optimized_kprobe *op; | |
730 | ||
731 | op = container_of(p, struct optimized_kprobe, kp); | |
732 | arch_prepare_optimized_kprobe(op); | |
733 | } | |
734 | ||
afd66255 MH |
735 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
736 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
737 | { | |
738 | struct optimized_kprobe *op; | |
739 | ||
740 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
741 | if (!op) | |
742 | return NULL; | |
743 | ||
744 | INIT_LIST_HEAD(&op->list); | |
745 | op->kp.addr = p->addr; | |
746 | arch_prepare_optimized_kprobe(op); | |
747 | ||
748 | return &op->kp; | |
749 | } | |
750 | ||
751 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); | |
752 | ||
753 | /* | |
754 | * Prepare an optimized_kprobe and optimize it | |
755 | * NOTE: p must be a normal registered kprobe | |
756 | */ | |
757 | static __kprobes void try_to_optimize_kprobe(struct kprobe *p) | |
758 | { | |
759 | struct kprobe *ap; | |
760 | struct optimized_kprobe *op; | |
761 | ||
ae6aa16f MH |
762 | /* Impossible to optimize ftrace-based kprobe */ |
763 | if (kprobe_ftrace(p)) | |
764 | return; | |
765 | ||
25764288 MH |
766 | /* For preparing optimization, jump_label_text_reserved() is called */ |
767 | jump_label_lock(); | |
768 | mutex_lock(&text_mutex); | |
769 | ||
afd66255 MH |
770 | ap = alloc_aggr_kprobe(p); |
771 | if (!ap) | |
25764288 | 772 | goto out; |
afd66255 MH |
773 | |
774 | op = container_of(ap, struct optimized_kprobe, kp); | |
775 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
776 | /* If failed to setup optimizing, fallback to kprobe */ | |
6274de49 MH |
777 | arch_remove_optimized_kprobe(op); |
778 | kfree(op); | |
25764288 | 779 | goto out; |
afd66255 MH |
780 | } |
781 | ||
782 | init_aggr_kprobe(ap, p); | |
25764288 MH |
783 | optimize_kprobe(ap); /* This just kicks optimizer thread */ |
784 | ||
785 | out: | |
786 | mutex_unlock(&text_mutex); | |
787 | jump_label_unlock(); | |
afd66255 MH |
788 | } |
789 | ||
b2be84df | 790 | #ifdef CONFIG_SYSCTL |
43948f50 | 791 | /* This should be called with kprobe_mutex locked */ |
b2be84df MH |
792 | static void __kprobes optimize_all_kprobes(void) |
793 | { | |
794 | struct hlist_head *head; | |
795 | struct hlist_node *node; | |
796 | struct kprobe *p; | |
797 | unsigned int i; | |
798 | ||
799 | /* If optimization is already allowed, just return */ | |
800 | if (kprobes_allow_optimization) | |
801 | return; | |
802 | ||
803 | kprobes_allow_optimization = true; | |
b2be84df MH |
804 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
805 | head = &kprobe_table[i]; | |
806 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
807 | if (!kprobe_disabled(p)) | |
808 | optimize_kprobe(p); | |
809 | } | |
b2be84df MH |
810 | printk(KERN_INFO "Kprobes globally optimized\n"); |
811 | } | |
812 | ||
43948f50 | 813 | /* This should be called with kprobe_mutex locked */ |
b2be84df MH |
814 | static void __kprobes unoptimize_all_kprobes(void) |
815 | { | |
816 | struct hlist_head *head; | |
817 | struct hlist_node *node; | |
818 | struct kprobe *p; | |
819 | unsigned int i; | |
820 | ||
821 | /* If optimization is already prohibited, just return */ | |
822 | if (!kprobes_allow_optimization) | |
823 | return; | |
824 | ||
825 | kprobes_allow_optimization = false; | |
b2be84df MH |
826 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
827 | head = &kprobe_table[i]; | |
828 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
829 | if (!kprobe_disabled(p)) | |
6274de49 | 830 | unoptimize_kprobe(p, false); |
b2be84df MH |
831 | } |
832 | } | |
6274de49 MH |
833 | /* Wait for unoptimizing completion */ |
834 | wait_for_kprobe_optimizer(); | |
835 | printk(KERN_INFO "Kprobes globally unoptimized\n"); | |
b2be84df MH |
836 | } |
837 | ||
838 | int sysctl_kprobes_optimization; | |
839 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, | |
840 | void __user *buffer, size_t *length, | |
841 | loff_t *ppos) | |
842 | { | |
843 | int ret; | |
844 | ||
845 | mutex_lock(&kprobe_mutex); | |
846 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; | |
847 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
848 | ||
849 | if (sysctl_kprobes_optimization) | |
850 | optimize_all_kprobes(); | |
851 | else | |
852 | unoptimize_all_kprobes(); | |
853 | mutex_unlock(&kprobe_mutex); | |
854 | ||
855 | return ret; | |
856 | } | |
857 | #endif /* CONFIG_SYSCTL */ | |
858 | ||
6274de49 | 859 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
afd66255 MH |
860 | static void __kprobes __arm_kprobe(struct kprobe *p) |
861 | { | |
6d8e40a8 | 862 | struct kprobe *_p; |
afd66255 MH |
863 | |
864 | /* Check collision with other optimized kprobes */ | |
6d8e40a8 MH |
865 | _p = get_optimized_kprobe((unsigned long)p->addr); |
866 | if (unlikely(_p)) | |
6274de49 MH |
867 | /* Fallback to unoptimized kprobe */ |
868 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
869 | |
870 | arch_arm_kprobe(p); | |
871 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
872 | } | |
873 | ||
6274de49 MH |
874 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
875 | static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt) | |
afd66255 | 876 | { |
6d8e40a8 | 877 | struct kprobe *_p; |
afd66255 | 878 | |
6274de49 | 879 | unoptimize_kprobe(p, false); /* Try to unoptimize */ |
afd66255 | 880 | |
6274de49 MH |
881 | if (!kprobe_queued(p)) { |
882 | arch_disarm_kprobe(p); | |
883 | /* If another kprobe was blocked, optimize it. */ | |
884 | _p = get_optimized_kprobe((unsigned long)p->addr); | |
885 | if (unlikely(_p) && reopt) | |
886 | optimize_kprobe(_p); | |
887 | } | |
888 | /* TODO: reoptimize others after unoptimized this probe */ | |
afd66255 MH |
889 | } |
890 | ||
891 | #else /* !CONFIG_OPTPROBES */ | |
892 | ||
893 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 894 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
895 | #define kill_optimized_kprobe(p) do {} while (0) |
896 | #define prepare_optimized_kprobe(p) do {} while (0) | |
897 | #define try_to_optimize_kprobe(p) do {} while (0) | |
898 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
899 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
900 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
901 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 902 | |
0490cd1f MH |
903 | /* There should be no unused kprobes can be reused without optimization */ |
904 | static void reuse_unused_kprobe(struct kprobe *ap) | |
905 | { | |
906 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); | |
907 | BUG_ON(kprobe_unused(ap)); | |
908 | } | |
909 | ||
afd66255 MH |
910 | static __kprobes void free_aggr_kprobe(struct kprobe *p) |
911 | { | |
6274de49 | 912 | arch_remove_kprobe(p); |
afd66255 MH |
913 | kfree(p); |
914 | } | |
915 | ||
916 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
917 | { | |
918 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
919 | } | |
920 | #endif /* CONFIG_OPTPROBES */ | |
921 | ||
ae6aa16f MH |
922 | #ifdef KPROBES_CAN_USE_FTRACE |
923 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { | |
e5253896 | 924 | .func = kprobe_ftrace_handler, |
ae6aa16f MH |
925 | .flags = FTRACE_OPS_FL_SAVE_REGS, |
926 | }; | |
927 | static int kprobe_ftrace_enabled; | |
928 | ||
929 | /* Must ensure p->addr is really on ftrace */ | |
930 | static int __kprobes prepare_kprobe(struct kprobe *p) | |
931 | { | |
932 | if (!kprobe_ftrace(p)) | |
933 | return arch_prepare_kprobe(p); | |
934 | ||
935 | return arch_prepare_kprobe_ftrace(p); | |
936 | } | |
937 | ||
938 | /* Caller must lock kprobe_mutex */ | |
939 | static void __kprobes arm_kprobe_ftrace(struct kprobe *p) | |
940 | { | |
941 | int ret; | |
942 | ||
943 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
944 | (unsigned long)p->addr, 0, 0); | |
945 | WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
946 | kprobe_ftrace_enabled++; | |
947 | if (kprobe_ftrace_enabled == 1) { | |
948 | ret = register_ftrace_function(&kprobe_ftrace_ops); | |
949 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
950 | } | |
951 | } | |
952 | ||
953 | /* Caller must lock kprobe_mutex */ | |
954 | static void __kprobes disarm_kprobe_ftrace(struct kprobe *p) | |
955 | { | |
956 | int ret; | |
957 | ||
958 | kprobe_ftrace_enabled--; | |
959 | if (kprobe_ftrace_enabled == 0) { | |
960 | ret = unregister_ftrace_function(&kprobe_ftrace_ops); | |
961 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
962 | } | |
963 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
964 | (unsigned long)p->addr, 1, 0); | |
965 | WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
966 | } | |
967 | #else /* !KPROBES_CAN_USE_FTRACE */ | |
968 | #define prepare_kprobe(p) arch_prepare_kprobe(p) | |
969 | #define arm_kprobe_ftrace(p) do {} while (0) | |
970 | #define disarm_kprobe_ftrace(p) do {} while (0) | |
971 | #endif | |
972 | ||
201517a7 MH |
973 | /* Arm a kprobe with text_mutex */ |
974 | static void __kprobes arm_kprobe(struct kprobe *kp) | |
975 | { | |
ae6aa16f MH |
976 | if (unlikely(kprobe_ftrace(kp))) { |
977 | arm_kprobe_ftrace(kp); | |
978 | return; | |
979 | } | |
afd66255 MH |
980 | /* |
981 | * Here, since __arm_kprobe() doesn't use stop_machine(), | |
982 | * this doesn't cause deadlock on text_mutex. So, we don't | |
983 | * need get_online_cpus(). | |
984 | */ | |
201517a7 | 985 | mutex_lock(&text_mutex); |
afd66255 | 986 | __arm_kprobe(kp); |
201517a7 MH |
987 | mutex_unlock(&text_mutex); |
988 | } | |
989 | ||
990 | /* Disarm a kprobe with text_mutex */ | |
ae6aa16f | 991 | static void __kprobes disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 992 | { |
ae6aa16f MH |
993 | if (unlikely(kprobe_ftrace(kp))) { |
994 | disarm_kprobe_ftrace(kp); | |
995 | return; | |
996 | } | |
6274de49 | 997 | /* Ditto */ |
201517a7 | 998 | mutex_lock(&text_mutex); |
ae6aa16f | 999 | __disarm_kprobe(kp, reopt); |
201517a7 MH |
1000 | mutex_unlock(&text_mutex); |
1001 | } | |
1002 | ||
64f562c6 AM |
1003 | /* |
1004 | * Aggregate handlers for multiple kprobes support - these handlers | |
1005 | * take care of invoking the individual kprobe handlers on p->list | |
1006 | */ | |
d0aaff97 | 1007 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
1008 | { |
1009 | struct kprobe *kp; | |
1010 | ||
3516a460 | 1011 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1012 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1013 | set_kprobe_instance(kp); |
8b0914ea PP |
1014 | if (kp->pre_handler(kp, regs)) |
1015 | return 1; | |
64f562c6 | 1016 | } |
e6584523 | 1017 | reset_kprobe_instance(); |
64f562c6 AM |
1018 | } |
1019 | return 0; | |
1020 | } | |
1021 | ||
d0aaff97 PP |
1022 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1023 | unsigned long flags) | |
64f562c6 AM |
1024 | { |
1025 | struct kprobe *kp; | |
1026 | ||
3516a460 | 1027 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1028 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1029 | set_kprobe_instance(kp); |
64f562c6 | 1030 | kp->post_handler(kp, regs, flags); |
e6584523 | 1031 | reset_kprobe_instance(); |
64f562c6 AM |
1032 | } |
1033 | } | |
64f562c6 AM |
1034 | } |
1035 | ||
d0aaff97 PP |
1036 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
1037 | int trapnr) | |
64f562c6 | 1038 | { |
b76834bc | 1039 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 | 1040 | |
64f562c6 AM |
1041 | /* |
1042 | * if we faulted "during" the execution of a user specified | |
1043 | * probe handler, invoke just that probe's fault handler | |
1044 | */ | |
e6584523 AM |
1045 | if (cur && cur->fault_handler) { |
1046 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
1047 | return 1; |
1048 | } | |
1049 | return 0; | |
1050 | } | |
1051 | ||
d0aaff97 | 1052 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 1053 | { |
b76834bc | 1054 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 AM |
1055 | int ret = 0; |
1056 | ||
1057 | if (cur && cur->break_handler) { | |
1058 | if (cur->break_handler(cur, regs)) | |
1059 | ret = 1; | |
8b0914ea | 1060 | } |
e6584523 AM |
1061 | reset_kprobe_instance(); |
1062 | return ret; | |
8b0914ea PP |
1063 | } |
1064 | ||
bf8d5c52 KA |
1065 | /* Walks the list and increments nmissed count for multiprobe case */ |
1066 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
1067 | { | |
1068 | struct kprobe *kp; | |
afd66255 | 1069 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1070 | p->nmissed++; |
1071 | } else { | |
1072 | list_for_each_entry_rcu(kp, &p->list, list) | |
1073 | kp->nmissed++; | |
1074 | } | |
1075 | return; | |
1076 | } | |
1077 | ||
99219a3f | 1078 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
1079 | struct hlist_head *head) | |
b94cce92 | 1080 | { |
ef53d9c5 S |
1081 | struct kretprobe *rp = ri->rp; |
1082 | ||
b94cce92 HN |
1083 | /* remove rp inst off the rprobe_inst_table */ |
1084 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
1085 | INIT_HLIST_NODE(&ri->hlist); |
1086 | if (likely(rp)) { | |
ec484608 | 1087 | raw_spin_lock(&rp->lock); |
ef53d9c5 | 1088 | hlist_add_head(&ri->hlist, &rp->free_instances); |
ec484608 | 1089 | raw_spin_unlock(&rp->lock); |
b94cce92 HN |
1090 | } else |
1091 | /* Unregistering */ | |
99219a3f | 1092 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
1093 | } |
1094 | ||
017c39bd | 1095 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 | 1096 | struct hlist_head **head, unsigned long *flags) |
635c17c2 | 1097 | __acquires(hlist_lock) |
ef53d9c5 S |
1098 | { |
1099 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1100 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1101 | |
1102 | *head = &kretprobe_inst_table[hash]; | |
1103 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1104 | raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5 S |
1105 | } |
1106 | ||
017c39bd MH |
1107 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
1108 | unsigned long *flags) | |
635c17c2 | 1109 | __acquires(hlist_lock) |
b94cce92 | 1110 | { |
ec484608 TG |
1111 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1112 | raw_spin_lock_irqsave(hlist_lock, *flags); | |
ef53d9c5 S |
1113 | } |
1114 | ||
017c39bd MH |
1115 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
1116 | unsigned long *flags) | |
635c17c2 | 1117 | __releases(hlist_lock) |
ef53d9c5 S |
1118 | { |
1119 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1120 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1121 | |
1122 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1123 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
ef53d9c5 S |
1124 | } |
1125 | ||
6376b229 NK |
1126 | static void __kprobes kretprobe_table_unlock(unsigned long hash, |
1127 | unsigned long *flags) | |
635c17c2 | 1128 | __releases(hlist_lock) |
ef53d9c5 | 1129 | { |
ec484608 TG |
1130 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1131 | raw_spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
1132 | } |
1133 | ||
b94cce92 | 1134 | /* |
c6fd91f0 | 1135 | * This function is called from finish_task_switch when task tk becomes dead, |
1136 | * so that we can recycle any function-return probe instances associated | |
1137 | * with this task. These left over instances represent probed functions | |
1138 | * that have been called but will never return. | |
b94cce92 | 1139 | */ |
d0aaff97 | 1140 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 1141 | { |
62c27be0 | 1142 | struct kretprobe_instance *ri; |
99219a3f | 1143 | struct hlist_head *head, empty_rp; |
802eae7c | 1144 | struct hlist_node *node, *tmp; |
ef53d9c5 | 1145 | unsigned long hash, flags = 0; |
802eae7c | 1146 | |
ef53d9c5 S |
1147 | if (unlikely(!kprobes_initialized)) |
1148 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
1149 | return; | |
1150 | ||
d496aab5 | 1151 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 S |
1152 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1153 | head = &kretprobe_inst_table[hash]; | |
1154 | kretprobe_table_lock(hash, &flags); | |
62c27be0 | 1155 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
1156 | if (ri->task == tk) | |
99219a3f | 1157 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 1158 | } |
ef53d9c5 | 1159 | kretprobe_table_unlock(hash, &flags); |
99219a3f | 1160 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
1161 | hlist_del(&ri->hlist); | |
1162 | kfree(ri); | |
1163 | } | |
b94cce92 HN |
1164 | } |
1165 | ||
b94cce92 HN |
1166 | static inline void free_rp_inst(struct kretprobe *rp) |
1167 | { | |
1168 | struct kretprobe_instance *ri; | |
4c4308cb CH |
1169 | struct hlist_node *pos, *next; |
1170 | ||
ef53d9c5 S |
1171 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
1172 | hlist_del(&ri->hlist); | |
b94cce92 HN |
1173 | kfree(ri); |
1174 | } | |
1175 | } | |
1176 | ||
4a296e07 MH |
1177 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
1178 | { | |
ef53d9c5 | 1179 | unsigned long flags, hash; |
4a296e07 MH |
1180 | struct kretprobe_instance *ri; |
1181 | struct hlist_node *pos, *next; | |
ef53d9c5 S |
1182 | struct hlist_head *head; |
1183 | ||
4a296e07 | 1184 | /* No race here */ |
ef53d9c5 S |
1185 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1186 | kretprobe_table_lock(hash, &flags); | |
1187 | head = &kretprobe_inst_table[hash]; | |
1188 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
1189 | if (ri->rp == rp) | |
1190 | ri->rp = NULL; | |
1191 | } | |
1192 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 1193 | } |
4a296e07 MH |
1194 | free_rp_inst(rp); |
1195 | } | |
1196 | ||
8b0914ea | 1197 | /* |
b918e5e6 | 1198 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
1199 | * second jprobe at the address - two jprobes can't coexist |
1200 | */ | |
b918e5e6 | 1201 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1202 | { |
de5bd88d | 1203 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
afd66255 MH |
1204 | |
1205 | if (p->break_handler || p->post_handler) | |
6274de49 | 1206 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1207 | |
8b0914ea | 1208 | if (p->break_handler) { |
b918e5e6 | 1209 | if (ap->break_handler) |
36721656 | 1210 | return -EEXIST; |
b918e5e6 MH |
1211 | list_add_tail_rcu(&p->list, &ap->list); |
1212 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 1213 | } else |
b918e5e6 MH |
1214 | list_add_rcu(&p->list, &ap->list); |
1215 | if (p->post_handler && !ap->post_handler) | |
1216 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1217 | |
8b0914ea PP |
1218 | return 0; |
1219 | } | |
1220 | ||
64f562c6 AM |
1221 | /* |
1222 | * Fill in the required fields of the "manager kprobe". Replace the | |
1223 | * earlier kprobe in the hlist with the manager kprobe | |
1224 | */ | |
afd66255 | 1225 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1226 | { |
afd66255 | 1227 | /* Copy p's insn slot to ap */ |
8b0914ea | 1228 | copy_kprobe(p, ap); |
a9ad965e | 1229 | flush_insn_slot(ap); |
64f562c6 | 1230 | ap->addr = p->addr; |
afd66255 | 1231 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1232 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 1233 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
1234 | /* We don't care the kprobe which has gone. */ |
1235 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1236 | ap->post_handler = aggr_post_handler; |
e8386a0c | 1237 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 1238 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
1239 | |
1240 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1241 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1242 | |
afd66255 | 1243 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1244 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1245 | } |
1246 | ||
1247 | /* | |
1248 | * This is the second or subsequent kprobe at the address - handle | |
1249 | * the intricacies | |
64f562c6 | 1250 | */ |
6d8e40a8 | 1251 | static int __kprobes register_aggr_kprobe(struct kprobe *orig_p, |
d0aaff97 | 1252 | struct kprobe *p) |
64f562c6 AM |
1253 | { |
1254 | int ret = 0; | |
6d8e40a8 | 1255 | struct kprobe *ap = orig_p; |
64f562c6 | 1256 | |
25764288 MH |
1257 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1258 | jump_label_lock(); | |
1259 | /* | |
1260 | * Get online CPUs to avoid text_mutex deadlock.with stop machine, | |
1261 | * which is invoked by unoptimize_kprobe() in add_new_kprobe() | |
1262 | */ | |
1263 | get_online_cpus(); | |
1264 | mutex_lock(&text_mutex); | |
1265 | ||
6d8e40a8 MH |
1266 | if (!kprobe_aggrprobe(orig_p)) { |
1267 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
1268 | ap = alloc_aggr_kprobe(orig_p); | |
25764288 MH |
1269 | if (!ap) { |
1270 | ret = -ENOMEM; | |
1271 | goto out; | |
1272 | } | |
6d8e40a8 | 1273 | init_aggr_kprobe(ap, orig_p); |
6274de49 | 1274 | } else if (kprobe_unused(ap)) |
0490cd1f MH |
1275 | /* This probe is going to die. Rescue it */ |
1276 | reuse_unused_kprobe(ap); | |
b918e5e6 MH |
1277 | |
1278 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1279 | /* |
1280 | * Attempting to insert new probe at the same location that | |
1281 | * had a probe in the module vaddr area which already | |
1282 | * freed. So, the instruction slot has already been | |
1283 | * released. We need a new slot for the new probe. | |
1284 | */ | |
b918e5e6 | 1285 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1286 | if (ret) |
b918e5e6 MH |
1287 | /* |
1288 | * Even if fail to allocate new slot, don't need to | |
1289 | * free aggr_probe. It will be used next time, or | |
1290 | * freed by unregister_kprobe. | |
1291 | */ | |
25764288 | 1292 | goto out; |
de5bd88d | 1293 | |
afd66255 MH |
1294 | /* Prepare optimized instructions if possible. */ |
1295 | prepare_optimized_kprobe(ap); | |
1296 | ||
e8386a0c | 1297 | /* |
de5bd88d MH |
1298 | * Clear gone flag to prevent allocating new slot again, and |
1299 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1300 | */ |
de5bd88d MH |
1301 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1302 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1303 | } |
b918e5e6 | 1304 | |
afd66255 | 1305 | /* Copy ap's insn slot to p */ |
b918e5e6 | 1306 | copy_kprobe(ap, p); |
25764288 MH |
1307 | ret = add_new_kprobe(ap, p); |
1308 | ||
1309 | out: | |
1310 | mutex_unlock(&text_mutex); | |
1311 | put_online_cpus(); | |
1312 | jump_label_unlock(); | |
1313 | ||
1314 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1315 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
1316 | if (!kprobes_all_disarmed) | |
1317 | /* Arm the breakpoint again. */ | |
1318 | arm_kprobe(ap); | |
1319 | } | |
1320 | return ret; | |
64f562c6 AM |
1321 | } |
1322 | ||
d0aaff97 PP |
1323 | static int __kprobes in_kprobes_functions(unsigned long addr) |
1324 | { | |
3d8d996e SD |
1325 | struct kprobe_blackpoint *kb; |
1326 | ||
6f716acd CH |
1327 | if (addr >= (unsigned long)__kprobes_text_start && |
1328 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 1329 | return -EINVAL; |
3d8d996e SD |
1330 | /* |
1331 | * If there exists a kprobe_blacklist, verify and | |
1332 | * fail any probe registration in the prohibited area | |
1333 | */ | |
1334 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1335 | if (kb->start_addr) { | |
1336 | if (addr >= kb->start_addr && | |
1337 | addr < (kb->start_addr + kb->range)) | |
1338 | return -EINVAL; | |
1339 | } | |
1340 | } | |
d0aaff97 PP |
1341 | return 0; |
1342 | } | |
1343 | ||
b2a5cd69 MH |
1344 | /* |
1345 | * If we have a symbol_name argument, look it up and add the offset field | |
1346 | * to it. This way, we can specify a relative address to a symbol. | |
bc81d48d MH |
1347 | * This returns encoded errors if it fails to look up symbol or invalid |
1348 | * combination of parameters. | |
b2a5cd69 MH |
1349 | */ |
1350 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
1351 | { | |
1352 | kprobe_opcode_t *addr = p->addr; | |
bc81d48d MH |
1353 | |
1354 | if ((p->symbol_name && p->addr) || | |
1355 | (!p->symbol_name && !p->addr)) | |
1356 | goto invalid; | |
1357 | ||
b2a5cd69 | 1358 | if (p->symbol_name) { |
b2a5cd69 | 1359 | kprobe_lookup_name(p->symbol_name, addr); |
bc81d48d MH |
1360 | if (!addr) |
1361 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1362 | } |
1363 | ||
bc81d48d MH |
1364 | addr = (kprobe_opcode_t *)(((char *)addr) + p->offset); |
1365 | if (addr) | |
1366 | return addr; | |
1367 | ||
1368 | invalid: | |
1369 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1370 | } |
1371 | ||
1f0ab409 AM |
1372 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1373 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) | |
1374 | { | |
6d8e40a8 | 1375 | struct kprobe *ap, *list_p; |
1f0ab409 | 1376 | |
6d8e40a8 MH |
1377 | ap = get_kprobe(p->addr); |
1378 | if (unlikely(!ap)) | |
1f0ab409 AM |
1379 | return NULL; |
1380 | ||
6d8e40a8 MH |
1381 | if (p != ap) { |
1382 | list_for_each_entry_rcu(list_p, &ap->list, list) | |
1f0ab409 AM |
1383 | if (list_p == p) |
1384 | /* kprobe p is a valid probe */ | |
1385 | goto valid; | |
1386 | return NULL; | |
1387 | } | |
1388 | valid: | |
6d8e40a8 | 1389 | return ap; |
1f0ab409 AM |
1390 | } |
1391 | ||
1392 | /* Return error if the kprobe is being re-registered */ | |
1393 | static inline int check_kprobe_rereg(struct kprobe *p) | |
1394 | { | |
1395 | int ret = 0; | |
1f0ab409 AM |
1396 | |
1397 | mutex_lock(&kprobe_mutex); | |
6d8e40a8 | 1398 | if (__get_valid_kprobe(p)) |
1f0ab409 AM |
1399 | ret = -EINVAL; |
1400 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1401 | |
1f0ab409 AM |
1402 | return ret; |
1403 | } | |
1404 | ||
f7fa6ef0 MH |
1405 | static __kprobes int check_kprobe_address_safe(struct kprobe *p, |
1406 | struct module **probed_mod) | |
1da177e4 LT |
1407 | { |
1408 | int ret = 0; | |
ae6aa16f MH |
1409 | unsigned long ftrace_addr; |
1410 | ||
1411 | /* | |
1412 | * If the address is located on a ftrace nop, set the | |
1413 | * breakpoint to the following instruction. | |
1414 | */ | |
1415 | ftrace_addr = ftrace_location((unsigned long)p->addr); | |
1416 | if (ftrace_addr) { | |
1417 | #ifdef KPROBES_CAN_USE_FTRACE | |
1418 | /* Given address is not on the instruction boundary */ | |
1419 | if ((unsigned long)p->addr != ftrace_addr) | |
1420 | return -EILSEQ; | |
ae6aa16f MH |
1421 | p->flags |= KPROBE_FLAG_FTRACE; |
1422 | #else /* !KPROBES_CAN_USE_FTRACE */ | |
1423 | return -EINVAL; | |
1424 | #endif | |
1425 | } | |
1f0ab409 | 1426 | |
91bad2f8 | 1427 | jump_label_lock(); |
de31c3ca | 1428 | preempt_disable(); |
f7fa6ef0 MH |
1429 | |
1430 | /* Ensure it is not in reserved area nor out of text */ | |
ec30c5f3 | 1431 | if (!kernel_text_address((unsigned long) p->addr) || |
4554dbcb | 1432 | in_kprobes_functions((unsigned long) p->addr) || |
f986a499 PN |
1433 | jump_label_text_reserved(p->addr, p->addr)) { |
1434 | ret = -EINVAL; | |
f7fa6ef0 | 1435 | goto out; |
f986a499 | 1436 | } |
b3e55c72 | 1437 | |
f7fa6ef0 MH |
1438 | /* Check if are we probing a module */ |
1439 | *probed_mod = __module_text_address((unsigned long) p->addr); | |
1440 | if (*probed_mod) { | |
6f716acd | 1441 | /* |
e8386a0c MH |
1442 | * We must hold a refcount of the probed module while updating |
1443 | * its code to prohibit unexpected unloading. | |
df019b1d | 1444 | */ |
f7fa6ef0 MH |
1445 | if (unlikely(!try_module_get(*probed_mod))) { |
1446 | ret = -ENOENT; | |
1447 | goto out; | |
1448 | } | |
de31c3ca | 1449 | |
f24659d9 MH |
1450 | /* |
1451 | * If the module freed .init.text, we couldn't insert | |
1452 | * kprobes in there. | |
1453 | */ | |
f7fa6ef0 MH |
1454 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
1455 | (*probed_mod)->state != MODULE_STATE_COMING) { | |
1456 | module_put(*probed_mod); | |
1457 | *probed_mod = NULL; | |
1458 | ret = -ENOENT; | |
f24659d9 | 1459 | } |
df019b1d | 1460 | } |
f7fa6ef0 | 1461 | out: |
a189d035 | 1462 | preempt_enable(); |
de31c3ca | 1463 | jump_label_unlock(); |
1da177e4 | 1464 | |
f7fa6ef0 MH |
1465 | return ret; |
1466 | } | |
1467 | ||
1468 | int __kprobes register_kprobe(struct kprobe *p) | |
1469 | { | |
1470 | int ret; | |
1471 | struct kprobe *old_p; | |
1472 | struct module *probed_mod; | |
1473 | kprobe_opcode_t *addr; | |
1474 | ||
1475 | /* Adjust probe address from symbol */ | |
1476 | addr = kprobe_addr(p); | |
1477 | if (IS_ERR(addr)) | |
1478 | return PTR_ERR(addr); | |
1479 | p->addr = addr; | |
1480 | ||
1481 | ret = check_kprobe_rereg(p); | |
1482 | if (ret) | |
1483 | return ret; | |
1484 | ||
1485 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ | |
1486 | p->flags &= KPROBE_FLAG_DISABLED; | |
3516a460 | 1487 | p->nmissed = 0; |
9861668f | 1488 | INIT_LIST_HEAD(&p->list); |
afd66255 | 1489 | |
f7fa6ef0 MH |
1490 | ret = check_kprobe_address_safe(p, &probed_mod); |
1491 | if (ret) | |
1492 | return ret; | |
1493 | ||
1494 | mutex_lock(&kprobe_mutex); | |
afd66255 | 1495 | |
64f562c6 AM |
1496 | old_p = get_kprobe(p->addr); |
1497 | if (old_p) { | |
afd66255 | 1498 | /* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6 | 1499 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1500 | goto out; |
1501 | } | |
1da177e4 | 1502 | |
25764288 | 1503 | mutex_lock(&text_mutex); /* Avoiding text modification */ |
ae6aa16f | 1504 | ret = prepare_kprobe(p); |
25764288 | 1505 | mutex_unlock(&text_mutex); |
6f716acd | 1506 | if (ret) |
afd66255 | 1507 | goto out; |
49a2a1b8 | 1508 | |
64f562c6 | 1509 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1510 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1511 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1512 | ||
de5bd88d | 1513 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
25764288 | 1514 | arm_kprobe(p); |
afd66255 MH |
1515 | |
1516 | /* Try to optimize kprobe */ | |
1517 | try_to_optimize_kprobe(p); | |
74a0b576 | 1518 | |
1da177e4 | 1519 | out: |
7a7d1cf9 | 1520 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1521 | |
e8386a0c | 1522 | if (probed_mod) |
df019b1d | 1523 | module_put(probed_mod); |
e8386a0c | 1524 | |
1da177e4 LT |
1525 | return ret; |
1526 | } | |
99081ab5 | 1527 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1528 | |
6f0f1dd7 MH |
1529 | /* Check if all probes on the aggrprobe are disabled */ |
1530 | static int __kprobes aggr_kprobe_disabled(struct kprobe *ap) | |
1531 | { | |
1532 | struct kprobe *kp; | |
1533 | ||
1534 | list_for_each_entry_rcu(kp, &ap->list, list) | |
1535 | if (!kprobe_disabled(kp)) | |
1536 | /* | |
1537 | * There is an active probe on the list. | |
1538 | * We can't disable this ap. | |
1539 | */ | |
1540 | return 0; | |
1541 | ||
1542 | return 1; | |
1543 | } | |
1544 | ||
1545 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ | |
1546 | static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p) | |
1547 | { | |
1548 | struct kprobe *orig_p; | |
1549 | ||
1550 | /* Get an original kprobe for return */ | |
1551 | orig_p = __get_valid_kprobe(p); | |
1552 | if (unlikely(orig_p == NULL)) | |
1553 | return NULL; | |
1554 | ||
1555 | if (!kprobe_disabled(p)) { | |
1556 | /* Disable probe if it is a child probe */ | |
1557 | if (p != orig_p) | |
1558 | p->flags |= KPROBE_FLAG_DISABLED; | |
1559 | ||
1560 | /* Try to disarm and disable this/parent probe */ | |
1561 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
ae6aa16f | 1562 | disarm_kprobe(orig_p, true); |
6f0f1dd7 MH |
1563 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1564 | } | |
1565 | } | |
1566 | ||
1567 | return orig_p; | |
1568 | } | |
1569 | ||
de5bd88d MH |
1570 | /* |
1571 | * Unregister a kprobe without a scheduler synchronization. | |
1572 | */ | |
1573 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1574 | { | |
6d8e40a8 | 1575 | struct kprobe *ap, *list_p; |
de5bd88d | 1576 | |
6f0f1dd7 MH |
1577 | /* Disable kprobe. This will disarm it if needed. */ |
1578 | ap = __disable_kprobe(p); | |
6d8e40a8 | 1579 | if (ap == NULL) |
de5bd88d MH |
1580 | return -EINVAL; |
1581 | ||
6f0f1dd7 | 1582 | if (ap == p) |
bf8f6e5b | 1583 | /* |
6f0f1dd7 MH |
1584 | * This probe is an independent(and non-optimized) kprobe |
1585 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1586 | */ |
6f0f1dd7 MH |
1587 | goto disarmed; |
1588 | ||
1589 | /* Following process expects this probe is an aggrprobe */ | |
1590 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1591 | ||
6274de49 MH |
1592 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1593 | /* | |
1594 | * !disarmed could be happen if the probe is under delayed | |
1595 | * unoptimizing. | |
1596 | */ | |
6f0f1dd7 MH |
1597 | goto disarmed; |
1598 | else { | |
1599 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1600 | if (p->break_handler && !kprobe_gone(p)) |
6d8e40a8 | 1601 | ap->break_handler = NULL; |
e8386a0c | 1602 | if (p->post_handler && !kprobe_gone(p)) { |
6d8e40a8 | 1603 | list_for_each_entry_rcu(list_p, &ap->list, list) { |
9861668f MH |
1604 | if ((list_p != p) && (list_p->post_handler)) |
1605 | goto noclean; | |
1606 | } | |
6d8e40a8 | 1607 | ap->post_handler = NULL; |
9861668f MH |
1608 | } |
1609 | noclean: | |
6f0f1dd7 MH |
1610 | /* |
1611 | * Remove from the aggrprobe: this path will do nothing in | |
1612 | * __unregister_kprobe_bottom(). | |
1613 | */ | |
49a2a1b8 | 1614 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1615 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1616 | /* | |
1617 | * Try to optimize this probe again, because post | |
1618 | * handler may have been changed. | |
1619 | */ | |
1620 | optimize_kprobe(ap); | |
49a2a1b8 | 1621 | } |
9861668f | 1622 | return 0; |
6f0f1dd7 MH |
1623 | |
1624 | disarmed: | |
6274de49 | 1625 | BUG_ON(!kprobe_disarmed(ap)); |
6f0f1dd7 MH |
1626 | hlist_del_rcu(&ap->hlist); |
1627 | return 0; | |
9861668f | 1628 | } |
3516a460 | 1629 | |
9861668f MH |
1630 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
1631 | { | |
6d8e40a8 | 1632 | struct kprobe *ap; |
b3e55c72 | 1633 | |
e8386a0c | 1634 | if (list_empty(&p->list)) |
6274de49 | 1635 | /* This is an independent kprobe */ |
0498b635 | 1636 | arch_remove_kprobe(p); |
e8386a0c | 1637 | else if (list_is_singular(&p->list)) { |
6274de49 | 1638 | /* This is the last child of an aggrprobe */ |
6d8e40a8 | 1639 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1640 | list_del(&p->list); |
6d8e40a8 | 1641 | free_aggr_kprobe(ap); |
9861668f | 1642 | } |
6274de49 | 1643 | /* Otherwise, do nothing. */ |
9861668f MH |
1644 | } |
1645 | ||
49ad2fd7 | 1646 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1647 | { |
1648 | int i, ret = 0; | |
1649 | ||
1650 | if (num <= 0) | |
1651 | return -EINVAL; | |
1652 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1653 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1654 | if (ret < 0) { |
1655 | if (i > 0) | |
1656 | unregister_kprobes(kps, i); | |
9861668f | 1657 | break; |
36721656 | 1658 | } |
49a2a1b8 | 1659 | } |
9861668f MH |
1660 | return ret; |
1661 | } | |
99081ab5 | 1662 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1663 | |
9861668f MH |
1664 | void __kprobes unregister_kprobe(struct kprobe *p) |
1665 | { | |
1666 | unregister_kprobes(&p, 1); | |
1667 | } | |
99081ab5 | 1668 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1669 | |
9861668f MH |
1670 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
1671 | { | |
1672 | int i; | |
1673 | ||
1674 | if (num <= 0) | |
1675 | return; | |
1676 | mutex_lock(&kprobe_mutex); | |
1677 | for (i = 0; i < num; i++) | |
1678 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1679 | kps[i]->addr = NULL; | |
1680 | mutex_unlock(&kprobe_mutex); | |
1681 | ||
1682 | synchronize_sched(); | |
1683 | for (i = 0; i < num; i++) | |
1684 | if (kps[i]->addr) | |
1685 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1686 | } |
99081ab5 | 1687 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 LT |
1688 | |
1689 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
1690 | .notifier_call = kprobe_exceptions_notify, |
1691 | .priority = 0x7fffffff /* we need to be notified first */ | |
1692 | }; | |
1693 | ||
3d7e3382 ME |
1694 | unsigned long __weak arch_deref_entry_point(void *entry) |
1695 | { | |
1696 | return (unsigned long)entry; | |
1697 | } | |
1da177e4 | 1698 | |
49ad2fd7 | 1699 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 1700 | { |
26b31c19 MH |
1701 | struct jprobe *jp; |
1702 | int ret = 0, i; | |
3d7e3382 | 1703 | |
26b31c19 | 1704 | if (num <= 0) |
3d7e3382 | 1705 | return -EINVAL; |
26b31c19 | 1706 | for (i = 0; i < num; i++) { |
05662bdb | 1707 | unsigned long addr, offset; |
26b31c19 MH |
1708 | jp = jps[i]; |
1709 | addr = arch_deref_entry_point(jp->entry); | |
1710 | ||
05662bdb NK |
1711 | /* Verify probepoint is a function entry point */ |
1712 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && | |
1713 | offset == 0) { | |
1714 | jp->kp.pre_handler = setjmp_pre_handler; | |
1715 | jp->kp.break_handler = longjmp_break_handler; | |
1716 | ret = register_kprobe(&jp->kp); | |
1717 | } else | |
1718 | ret = -EINVAL; | |
edbaadbe | 1719 | |
67dddaad MH |
1720 | if (ret < 0) { |
1721 | if (i > 0) | |
1722 | unregister_jprobes(jps, i); | |
26b31c19 MH |
1723 | break; |
1724 | } | |
1725 | } | |
1726 | return ret; | |
1727 | } | |
99081ab5 | 1728 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 1729 | |
26b31c19 MH |
1730 | int __kprobes register_jprobe(struct jprobe *jp) |
1731 | { | |
49ad2fd7 | 1732 | return register_jprobes(&jp, 1); |
1da177e4 | 1733 | } |
99081ab5 | 1734 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 1735 | |
d0aaff97 | 1736 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 1737 | { |
26b31c19 MH |
1738 | unregister_jprobes(&jp, 1); |
1739 | } | |
99081ab5 | 1740 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 1741 | |
26b31c19 MH |
1742 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
1743 | { | |
1744 | int i; | |
1745 | ||
1746 | if (num <= 0) | |
1747 | return; | |
1748 | mutex_lock(&kprobe_mutex); | |
1749 | for (i = 0; i < num; i++) | |
1750 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
1751 | jps[i]->kp.addr = NULL; | |
1752 | mutex_unlock(&kprobe_mutex); | |
1753 | ||
1754 | synchronize_sched(); | |
1755 | for (i = 0; i < num; i++) { | |
1756 | if (jps[i]->kp.addr) | |
1757 | __unregister_kprobe_bottom(&jps[i]->kp); | |
1758 | } | |
1da177e4 | 1759 | } |
99081ab5 | 1760 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 1761 | |
9edddaa2 | 1762 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1763 | /* |
1764 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1765 | * hits it will set up the return probe. | |
1766 | */ | |
1767 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
1768 | struct pt_regs *regs) | |
1769 | { | |
1770 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1771 | unsigned long hash, flags = 0; |
1772 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
1773 | |
1774 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 | 1775 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
ec484608 | 1776 | raw_spin_lock_irqsave(&rp->lock, flags); |
4c4308cb | 1777 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1778 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1779 | struct kretprobe_instance, hlist); |
1780 | hlist_del(&ri->hlist); | |
ec484608 | 1781 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1782 | |
4c4308cb CH |
1783 | ri->rp = rp; |
1784 | ri->task = current; | |
f47cd9b5 | 1785 | |
55ca6140 JL |
1786 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1787 | raw_spin_lock_irqsave(&rp->lock, flags); | |
1788 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
1789 | raw_spin_unlock_irqrestore(&rp->lock, flags); | |
f47cd9b5 | 1790 | return 0; |
55ca6140 | 1791 | } |
f47cd9b5 | 1792 | |
4c4308cb CH |
1793 | arch_prepare_kretprobe(ri, regs); |
1794 | ||
1795 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1796 | INIT_HLIST_NODE(&ri->hlist); |
1797 | kretprobe_table_lock(hash, &flags); | |
1798 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1799 | kretprobe_table_unlock(hash, &flags); | |
1800 | } else { | |
4c4308cb | 1801 | rp->nmissed++; |
ec484608 | 1802 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1803 | } |
e65cefe8 AB |
1804 | return 0; |
1805 | } | |
1806 | ||
49ad2fd7 | 1807 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1808 | { |
1809 | int ret = 0; | |
1810 | struct kretprobe_instance *inst; | |
1811 | int i; | |
b2a5cd69 | 1812 | void *addr; |
f438d914 MH |
1813 | |
1814 | if (kretprobe_blacklist_size) { | |
b2a5cd69 | 1815 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
1816 | if (IS_ERR(addr)) |
1817 | return PTR_ERR(addr); | |
f438d914 MH |
1818 | |
1819 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1820 | if (kretprobe_blacklist[i].addr == addr) | |
1821 | return -EINVAL; | |
1822 | } | |
1823 | } | |
b94cce92 HN |
1824 | |
1825 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1826 | rp->kp.post_handler = NULL; |
1827 | rp->kp.fault_handler = NULL; | |
1828 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1829 | |
1830 | /* Pre-allocate memory for max kretprobe instances */ | |
1831 | if (rp->maxactive <= 0) { | |
1832 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1833 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1834 | #else |
4dae560f | 1835 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1836 | #endif |
1837 | } | |
ec484608 | 1838 | raw_spin_lock_init(&rp->lock); |
b94cce92 HN |
1839 | INIT_HLIST_HEAD(&rp->free_instances); |
1840 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1841 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1842 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1843 | if (inst == NULL) { |
1844 | free_rp_inst(rp); | |
1845 | return -ENOMEM; | |
1846 | } | |
ef53d9c5 S |
1847 | INIT_HLIST_NODE(&inst->hlist); |
1848 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1849 | } |
1850 | ||
1851 | rp->nmissed = 0; | |
1852 | /* Establish function entry probe point */ | |
49ad2fd7 | 1853 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1854 | if (ret != 0) |
b94cce92 HN |
1855 | free_rp_inst(rp); |
1856 | return ret; | |
1857 | } | |
99081ab5 | 1858 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1859 | |
49ad2fd7 | 1860 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1861 | { |
1862 | int ret = 0, i; | |
1863 | ||
1864 | if (num <= 0) | |
1865 | return -EINVAL; | |
1866 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1867 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1868 | if (ret < 0) { |
1869 | if (i > 0) | |
1870 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1871 | break; |
1872 | } | |
1873 | } | |
1874 | return ret; | |
1875 | } | |
99081ab5 | 1876 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1877 | |
4a296e07 MH |
1878 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1879 | { | |
1880 | unregister_kretprobes(&rp, 1); | |
1881 | } | |
99081ab5 | 1882 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1883 | |
4a296e07 MH |
1884 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1885 | { | |
1886 | int i; | |
1887 | ||
1888 | if (num <= 0) | |
1889 | return; | |
1890 | mutex_lock(&kprobe_mutex); | |
1891 | for (i = 0; i < num; i++) | |
1892 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1893 | rps[i]->kp.addr = NULL; | |
1894 | mutex_unlock(&kprobe_mutex); | |
1895 | ||
1896 | synchronize_sched(); | |
1897 | for (i = 0; i < num; i++) { | |
1898 | if (rps[i]->kp.addr) { | |
1899 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1900 | cleanup_rp_inst(rps[i]); | |
1901 | } | |
1902 | } | |
1903 | } | |
99081ab5 | 1904 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 1905 | |
9edddaa2 | 1906 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1907 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1908 | { |
1909 | return -ENOSYS; | |
1910 | } | |
99081ab5 | 1911 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1912 | |
4a296e07 | 1913 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1914 | { |
4a296e07 | 1915 | return -ENOSYS; |
346fd59b | 1916 | } |
99081ab5 MH |
1917 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1918 | ||
d0aaff97 | 1919 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1920 | { |
4a296e07 | 1921 | } |
99081ab5 | 1922 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 1923 | |
4a296e07 MH |
1924 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1925 | { | |
1926 | } | |
99081ab5 | 1927 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 1928 | |
4a296e07 MH |
1929 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1930 | struct pt_regs *regs) | |
1931 | { | |
1932 | return 0; | |
b94cce92 HN |
1933 | } |
1934 | ||
4a296e07 MH |
1935 | #endif /* CONFIG_KRETPROBES */ |
1936 | ||
e8386a0c MH |
1937 | /* Set the kprobe gone and remove its instruction buffer. */ |
1938 | static void __kprobes kill_kprobe(struct kprobe *p) | |
1939 | { | |
1940 | struct kprobe *kp; | |
de5bd88d | 1941 | |
e8386a0c | 1942 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 1943 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
1944 | /* |
1945 | * If this is an aggr_kprobe, we have to list all the | |
1946 | * chained probes and mark them GONE. | |
1947 | */ | |
1948 | list_for_each_entry_rcu(kp, &p->list, list) | |
1949 | kp->flags |= KPROBE_FLAG_GONE; | |
1950 | p->post_handler = NULL; | |
1951 | p->break_handler = NULL; | |
afd66255 | 1952 | kill_optimized_kprobe(p); |
e8386a0c MH |
1953 | } |
1954 | /* | |
1955 | * Here, we can remove insn_slot safely, because no thread calls | |
1956 | * the original probed function (which will be freed soon) any more. | |
1957 | */ | |
1958 | arch_remove_kprobe(p); | |
1959 | } | |
1960 | ||
c0614829 MH |
1961 | /* Disable one kprobe */ |
1962 | int __kprobes disable_kprobe(struct kprobe *kp) | |
1963 | { | |
1964 | int ret = 0; | |
c0614829 MH |
1965 | |
1966 | mutex_lock(&kprobe_mutex); | |
1967 | ||
6f0f1dd7 MH |
1968 | /* Disable this kprobe */ |
1969 | if (__disable_kprobe(kp) == NULL) | |
c0614829 | 1970 | ret = -EINVAL; |
c0614829 | 1971 | |
c0614829 MH |
1972 | mutex_unlock(&kprobe_mutex); |
1973 | return ret; | |
1974 | } | |
1975 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
1976 | ||
1977 | /* Enable one kprobe */ | |
1978 | int __kprobes enable_kprobe(struct kprobe *kp) | |
1979 | { | |
1980 | int ret = 0; | |
1981 | struct kprobe *p; | |
1982 | ||
1983 | mutex_lock(&kprobe_mutex); | |
1984 | ||
1985 | /* Check whether specified probe is valid. */ | |
1986 | p = __get_valid_kprobe(kp); | |
1987 | if (unlikely(p == NULL)) { | |
1988 | ret = -EINVAL; | |
1989 | goto out; | |
1990 | } | |
1991 | ||
1992 | if (kprobe_gone(kp)) { | |
1993 | /* This kprobe has gone, we couldn't enable it. */ | |
1994 | ret = -EINVAL; | |
1995 | goto out; | |
1996 | } | |
1997 | ||
1998 | if (p != kp) | |
1999 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
2000 | ||
2001 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
2002 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
2003 | arm_kprobe(p); | |
2004 | } | |
2005 | out: | |
2006 | mutex_unlock(&kprobe_mutex); | |
2007 | return ret; | |
2008 | } | |
2009 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
2010 | ||
24851d24 FW |
2011 | void __kprobes dump_kprobe(struct kprobe *kp) |
2012 | { | |
2013 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
2014 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
2015 | kp->symbol_name, kp->addr, kp->offset); | |
2016 | } | |
2017 | ||
e8386a0c MH |
2018 | /* Module notifier call back, checking kprobes on the module */ |
2019 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, | |
2020 | unsigned long val, void *data) | |
2021 | { | |
2022 | struct module *mod = data; | |
2023 | struct hlist_head *head; | |
2024 | struct hlist_node *node; | |
2025 | struct kprobe *p; | |
2026 | unsigned int i; | |
f24659d9 | 2027 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2028 | |
f24659d9 | 2029 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2030 | return NOTIFY_DONE; |
2031 | ||
2032 | /* | |
f24659d9 MH |
2033 | * When MODULE_STATE_GOING was notified, both of module .text and |
2034 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
2035 | * notified, only .init.text section would be freed. We need to | |
2036 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
2037 | */ |
2038 | mutex_lock(&kprobe_mutex); | |
2039 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2040 | head = &kprobe_table[i]; | |
2041 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
f24659d9 MH |
2042 | if (within_module_init((unsigned long)p->addr, mod) || |
2043 | (checkcore && | |
2044 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2045 | /* |
2046 | * The vaddr this probe is installed will soon | |
2047 | * be vfreed buy not synced to disk. Hence, | |
2048 | * disarming the breakpoint isn't needed. | |
2049 | */ | |
2050 | kill_kprobe(p); | |
2051 | } | |
2052 | } | |
2053 | mutex_unlock(&kprobe_mutex); | |
2054 | return NOTIFY_DONE; | |
2055 | } | |
2056 | ||
2057 | static struct notifier_block kprobe_module_nb = { | |
2058 | .notifier_call = kprobes_module_callback, | |
2059 | .priority = 0 | |
2060 | }; | |
2061 | ||
1da177e4 LT |
2062 | static int __init init_kprobes(void) |
2063 | { | |
2064 | int i, err = 0; | |
3d8d996e SD |
2065 | unsigned long offset = 0, size = 0; |
2066 | char *modname, namebuf[128]; | |
2067 | const char *symbol_name; | |
2068 | void *addr; | |
2069 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
2070 | |
2071 | /* FIXME allocate the probe table, currently defined statically */ | |
2072 | /* initialize all list heads */ | |
b94cce92 | 2073 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 2074 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 2075 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ec484608 | 2076 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 2077 | } |
1da177e4 | 2078 | |
3d8d996e SD |
2079 | /* |
2080 | * Lookup and populate the kprobe_blacklist. | |
2081 | * | |
2082 | * Unlike the kretprobe blacklist, we'll need to determine | |
2083 | * the range of addresses that belong to the said functions, | |
2084 | * since a kprobe need not necessarily be at the beginning | |
2085 | * of a function. | |
2086 | */ | |
2087 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
2088 | kprobe_lookup_name(kb->name, addr); | |
2089 | if (!addr) | |
2090 | continue; | |
2091 | ||
2092 | kb->start_addr = (unsigned long)addr; | |
2093 | symbol_name = kallsyms_lookup(kb->start_addr, | |
2094 | &size, &offset, &modname, namebuf); | |
2095 | if (!symbol_name) | |
2096 | kb->range = 0; | |
2097 | else | |
2098 | kb->range = size; | |
2099 | } | |
2100 | ||
f438d914 MH |
2101 | if (kretprobe_blacklist_size) { |
2102 | /* lookup the function address from its name */ | |
2103 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
2104 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
2105 | kretprobe_blacklist[i].addr); | |
2106 | if (!kretprobe_blacklist[i].addr) | |
2107 | printk("kretprobe: lookup failed: %s\n", | |
2108 | kretprobe_blacklist[i].name); | |
2109 | } | |
2110 | } | |
2111 | ||
b2be84df MH |
2112 | #if defined(CONFIG_OPTPROBES) |
2113 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) | |
afd66255 MH |
2114 | /* Init kprobe_optinsn_slots */ |
2115 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
2116 | #endif | |
b2be84df MH |
2117 | /* By default, kprobes can be optimized */ |
2118 | kprobes_allow_optimization = true; | |
2119 | #endif | |
afd66255 | 2120 | |
e579abeb MH |
2121 | /* By default, kprobes are armed */ |
2122 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2123 | |
6772926b | 2124 | err = arch_init_kprobes(); |
802eae7c RL |
2125 | if (!err) |
2126 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
2127 | if (!err) |
2128 | err = register_module_notifier(&kprobe_module_nb); | |
2129 | ||
ef53d9c5 | 2130 | kprobes_initialized = (err == 0); |
802eae7c | 2131 | |
8c1c9356 AM |
2132 | if (!err) |
2133 | init_test_probes(); | |
1da177e4 LT |
2134 | return err; |
2135 | } | |
2136 | ||
346fd59b SD |
2137 | #ifdef CONFIG_DEBUG_FS |
2138 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
afd66255 | 2139 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2140 | { |
2141 | char *kprobe_type; | |
2142 | ||
2143 | if (p->pre_handler == pre_handler_kretprobe) | |
2144 | kprobe_type = "r"; | |
2145 | else if (p->pre_handler == setjmp_pre_handler) | |
2146 | kprobe_type = "j"; | |
2147 | else | |
2148 | kprobe_type = "k"; | |
afd66255 | 2149 | |
346fd59b | 2150 | if (sym) |
afd66255 | 2151 | seq_printf(pi, "%p %s %s+0x%x %s ", |
de5bd88d | 2152 | p->addr, kprobe_type, sym, offset, |
afd66255 | 2153 | (modname ? modname : " ")); |
346fd59b | 2154 | else |
afd66255 MH |
2155 | seq_printf(pi, "%p %s %p ", |
2156 | p->addr, kprobe_type, p->addr); | |
2157 | ||
2158 | if (!pp) | |
2159 | pp = p; | |
ae6aa16f | 2160 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2161 | (kprobe_gone(p) ? "[GONE]" : ""), |
2162 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2163 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2164 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2165 | } |
2166 | ||
2167 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
2168 | { | |
2169 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2170 | } | |
2171 | ||
2172 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
2173 | { | |
2174 | (*pos)++; | |
2175 | if (*pos >= KPROBE_TABLE_SIZE) | |
2176 | return NULL; | |
2177 | return pos; | |
2178 | } | |
2179 | ||
2180 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
2181 | { | |
2182 | /* Nothing to do */ | |
2183 | } | |
2184 | ||
2185 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
2186 | { | |
2187 | struct hlist_head *head; | |
2188 | struct hlist_node *node; | |
2189 | struct kprobe *p, *kp; | |
2190 | const char *sym = NULL; | |
2191 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 2192 | unsigned long offset = 0; |
346fd59b SD |
2193 | char *modname, namebuf[128]; |
2194 | ||
2195 | head = &kprobe_table[i]; | |
2196 | preempt_disable(); | |
2197 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 2198 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2199 | &offset, &modname, namebuf); |
afd66255 | 2200 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2201 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2202 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2203 | } else |
afd66255 | 2204 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2205 | } |
2206 | preempt_enable(); | |
2207 | return 0; | |
2208 | } | |
2209 | ||
88e9d34c | 2210 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
2211 | .start = kprobe_seq_start, |
2212 | .next = kprobe_seq_next, | |
2213 | .stop = kprobe_seq_stop, | |
2214 | .show = show_kprobe_addr | |
2215 | }; | |
2216 | ||
2217 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
2218 | { | |
2219 | return seq_open(filp, &kprobes_seq_ops); | |
2220 | } | |
2221 | ||
828c0950 | 2222 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
2223 | .open = kprobes_open, |
2224 | .read = seq_read, | |
2225 | .llseek = seq_lseek, | |
2226 | .release = seq_release, | |
2227 | }; | |
2228 | ||
e579abeb | 2229 | static void __kprobes arm_all_kprobes(void) |
bf8f6e5b AM |
2230 | { |
2231 | struct hlist_head *head; | |
2232 | struct hlist_node *node; | |
2233 | struct kprobe *p; | |
2234 | unsigned int i; | |
2235 | ||
2236 | mutex_lock(&kprobe_mutex); | |
2237 | ||
e579abeb MH |
2238 | /* If kprobes are armed, just return */ |
2239 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2240 | goto already_enabled; |
2241 | ||
afd66255 | 2242 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2243 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2244 | head = &kprobe_table[i]; | |
2245 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
de5bd88d | 2246 | if (!kprobe_disabled(p)) |
ae6aa16f | 2247 | arm_kprobe(p); |
bf8f6e5b AM |
2248 | } |
2249 | ||
e579abeb | 2250 | kprobes_all_disarmed = false; |
bf8f6e5b AM |
2251 | printk(KERN_INFO "Kprobes globally enabled\n"); |
2252 | ||
2253 | already_enabled: | |
2254 | mutex_unlock(&kprobe_mutex); | |
2255 | return; | |
2256 | } | |
2257 | ||
e579abeb | 2258 | static void __kprobes disarm_all_kprobes(void) |
bf8f6e5b AM |
2259 | { |
2260 | struct hlist_head *head; | |
2261 | struct hlist_node *node; | |
2262 | struct kprobe *p; | |
2263 | unsigned int i; | |
2264 | ||
2265 | mutex_lock(&kprobe_mutex); | |
2266 | ||
e579abeb | 2267 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2268 | if (kprobes_all_disarmed) { |
2269 | mutex_unlock(&kprobe_mutex); | |
2270 | return; | |
2271 | } | |
bf8f6e5b | 2272 | |
e579abeb | 2273 | kprobes_all_disarmed = true; |
bf8f6e5b | 2274 | printk(KERN_INFO "Kprobes globally disabled\n"); |
afd66255 | 2275 | |
bf8f6e5b AM |
2276 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2277 | head = &kprobe_table[i]; | |
2278 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
de5bd88d | 2279 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
ae6aa16f | 2280 | disarm_kprobe(p, false); |
bf8f6e5b AM |
2281 | } |
2282 | } | |
bf8f6e5b | 2283 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2284 | |
6274de49 MH |
2285 | /* Wait for disarming all kprobes by optimizer */ |
2286 | wait_for_kprobe_optimizer(); | |
bf8f6e5b AM |
2287 | } |
2288 | ||
2289 | /* | |
2290 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2291 | * when the bool state is switched. We can reuse that facility when | |
2292 | * available | |
2293 | */ | |
2294 | static ssize_t read_enabled_file_bool(struct file *file, | |
2295 | char __user *user_buf, size_t count, loff_t *ppos) | |
2296 | { | |
2297 | char buf[3]; | |
2298 | ||
e579abeb | 2299 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
2300 | buf[0] = '1'; |
2301 | else | |
2302 | buf[0] = '0'; | |
2303 | buf[1] = '\n'; | |
2304 | buf[2] = 0x00; | |
2305 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2306 | } | |
2307 | ||
2308 | static ssize_t write_enabled_file_bool(struct file *file, | |
2309 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2310 | { | |
2311 | char buf[32]; | |
efeb156e | 2312 | size_t buf_size; |
bf8f6e5b AM |
2313 | |
2314 | buf_size = min(count, (sizeof(buf)-1)); | |
2315 | if (copy_from_user(buf, user_buf, buf_size)) | |
2316 | return -EFAULT; | |
2317 | ||
2318 | switch (buf[0]) { | |
2319 | case 'y': | |
2320 | case 'Y': | |
2321 | case '1': | |
e579abeb | 2322 | arm_all_kprobes(); |
bf8f6e5b AM |
2323 | break; |
2324 | case 'n': | |
2325 | case 'N': | |
2326 | case '0': | |
e579abeb | 2327 | disarm_all_kprobes(); |
bf8f6e5b AM |
2328 | break; |
2329 | } | |
2330 | ||
2331 | return count; | |
2332 | } | |
2333 | ||
828c0950 | 2334 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2335 | .read = read_enabled_file_bool, |
2336 | .write = write_enabled_file_bool, | |
6038f373 | 2337 | .llseek = default_llseek, |
bf8f6e5b AM |
2338 | }; |
2339 | ||
346fd59b SD |
2340 | static int __kprobes debugfs_kprobe_init(void) |
2341 | { | |
2342 | struct dentry *dir, *file; | |
bf8f6e5b | 2343 | unsigned int value = 1; |
346fd59b SD |
2344 | |
2345 | dir = debugfs_create_dir("kprobes", NULL); | |
2346 | if (!dir) | |
2347 | return -ENOMEM; | |
2348 | ||
e3869792 | 2349 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
2350 | &debugfs_kprobes_operations); |
2351 | if (!file) { | |
2352 | debugfs_remove(dir); | |
2353 | return -ENOMEM; | |
2354 | } | |
2355 | ||
bf8f6e5b AM |
2356 | file = debugfs_create_file("enabled", 0600, dir, |
2357 | &value, &fops_kp); | |
2358 | if (!file) { | |
2359 | debugfs_remove(dir); | |
2360 | return -ENOMEM; | |
2361 | } | |
2362 | ||
346fd59b SD |
2363 | return 0; |
2364 | } | |
2365 | ||
2366 | late_initcall(debugfs_kprobe_init); | |
2367 | #endif /* CONFIG_DEBUG_FS */ | |
2368 | ||
2369 | module_init(init_kprobes); | |
1da177e4 | 2370 | |
99081ab5 | 2371 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 2372 | EXPORT_SYMBOL_GPL(jprobe_return); |