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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 | ||
4610ee1d MH |
124 | static int slots_per_page(struct kprobe_insn_cache *c) |
125 | { | |
126 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
127 | } | |
128 | ||
ab40c5c6 MH |
129 | enum kprobe_slot_state { |
130 | SLOT_CLEAN = 0, | |
131 | SLOT_DIRTY = 1, | |
132 | SLOT_USED = 2, | |
133 | }; | |
134 | ||
c802d64a HC |
135 | struct kprobe_insn_cache kprobe_insn_slots = { |
136 | .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), | |
4610ee1d MH |
137 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), |
138 | .insn_size = MAX_INSN_SIZE, | |
139 | .nr_garbage = 0, | |
140 | }; | |
141 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); | |
b4c6c34a | 142 | |
9ec4b1f3 | 143 | /** |
12941560 | 144 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
145 | * We allocate an executable page if there's no room on existing ones. |
146 | */ | |
c802d64a | 147 | kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
148 | { |
149 | struct kprobe_insn_page *kip; | |
c802d64a | 150 | kprobe_opcode_t *slot = NULL; |
9ec4b1f3 | 151 | |
c802d64a | 152 | mutex_lock(&c->mutex); |
6f716acd | 153 | retry: |
4610ee1d MH |
154 | list_for_each_entry(kip, &c->pages, list) { |
155 | if (kip->nused < slots_per_page(c)) { | |
9ec4b1f3 | 156 | int i; |
4610ee1d | 157 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
158 | if (kip->slot_used[i] == SLOT_CLEAN) { |
159 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 160 | kip->nused++; |
c802d64a HC |
161 | slot = kip->insns + (i * c->insn_size); |
162 | goto out; | |
9ec4b1f3 AM |
163 | } |
164 | } | |
4610ee1d MH |
165 | /* kip->nused is broken. Fix it. */ |
166 | kip->nused = slots_per_page(c); | |
167 | WARN_ON(1); | |
9ec4b1f3 AM |
168 | } |
169 | } | |
170 | ||
b4c6c34a | 171 | /* If there are any garbage slots, collect it and try again. */ |
4610ee1d | 172 | if (c->nr_garbage && collect_garbage_slots(c) == 0) |
b4c6c34a | 173 | goto retry; |
4610ee1d MH |
174 | |
175 | /* All out of space. Need to allocate a new page. */ | |
176 | kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); | |
6f716acd | 177 | if (!kip) |
c802d64a | 178 | goto out; |
9ec4b1f3 AM |
179 | |
180 | /* | |
181 | * Use module_alloc so this page is within +/- 2GB of where the | |
182 | * kernel image and loaded module images reside. This is required | |
183 | * so x86_64 can correctly handle the %rip-relative fixups. | |
184 | */ | |
185 | kip->insns = module_alloc(PAGE_SIZE); | |
186 | if (!kip->insns) { | |
187 | kfree(kip); | |
c802d64a | 188 | goto out; |
9ec4b1f3 | 189 | } |
c5cb5a2d | 190 | INIT_LIST_HEAD(&kip->list); |
4610ee1d | 191 | memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
ab40c5c6 | 192 | kip->slot_used[0] = SLOT_USED; |
9ec4b1f3 | 193 | kip->nused = 1; |
b4c6c34a | 194 | kip->ngarbage = 0; |
4610ee1d | 195 | list_add(&kip->list, &c->pages); |
c802d64a HC |
196 | slot = kip->insns; |
197 | out: | |
198 | mutex_unlock(&c->mutex); | |
199 | return slot; | |
12941560 MH |
200 | } |
201 | ||
b4c6c34a MH |
202 | /* Return 1 if all garbages are collected, otherwise 0. */ |
203 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
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)) { |
c5cb5a2d | 215 | list_del(&kip->list); |
b4c6c34a MH |
216 | module_free(NULL, kip->insns); |
217 | kfree(kip); | |
218 | } | |
219 | return 1; | |
220 | } | |
221 | return 0; | |
222 | } | |
223 | ||
4610ee1d | 224 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 225 | { |
c5cb5a2d | 226 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 227 | |
615d0ebb MH |
228 | /* Ensure no-one is interrupted on the garbages */ |
229 | synchronize_sched(); | |
b4c6c34a | 230 | |
4610ee1d | 231 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 232 | int i; |
b4c6c34a MH |
233 | if (kip->ngarbage == 0) |
234 | continue; | |
235 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 236 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 | 237 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
238 | collect_one_slot(kip, i)) |
239 | break; | |
240 | } | |
241 | } | |
4610ee1d | 242 | c->nr_garbage = 0; |
b4c6c34a MH |
243 | return 0; |
244 | } | |
245 | ||
c802d64a HC |
246 | void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
247 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
248 | { |
249 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 250 | |
c802d64a | 251 | mutex_lock(&c->mutex); |
4610ee1d | 252 | list_for_each_entry(kip, &c->pages, list) { |
83ff56f4 MH |
253 | long idx = ((long)slot - (long)kip->insns) / |
254 | (c->insn_size * sizeof(kprobe_opcode_t)); | |
4610ee1d MH |
255 | if (idx >= 0 && idx < slots_per_page(c)) { |
256 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
b4c6c34a | 257 | if (dirty) { |
4610ee1d | 258 | kip->slot_used[idx] = SLOT_DIRTY; |
b4c6c34a | 259 | kip->ngarbage++; |
4610ee1d MH |
260 | if (++c->nr_garbage > slots_per_page(c)) |
261 | collect_garbage_slots(c); | |
c5cb5a2d | 262 | } else |
4610ee1d | 263 | collect_one_slot(kip, idx); |
c802d64a | 264 | goto out; |
9ec4b1f3 AM |
265 | } |
266 | } | |
4610ee1d MH |
267 | /* Could not free this slot. */ |
268 | WARN_ON(1); | |
c802d64a HC |
269 | out: |
270 | mutex_unlock(&c->mutex); | |
4610ee1d | 271 | } |
6f716acd | 272 | |
afd66255 MH |
273 | #ifdef CONFIG_OPTPROBES |
274 | /* For optimized_kprobe buffer */ | |
c802d64a HC |
275 | struct kprobe_insn_cache kprobe_optinsn_slots = { |
276 | .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), | |
afd66255 MH |
277 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), |
278 | /* .insn_size is initialized later */ | |
279 | .nr_garbage = 0, | |
280 | }; | |
afd66255 | 281 | #endif |
2d14e39d | 282 | #endif |
9ec4b1f3 | 283 | |
e6584523 AM |
284 | /* We have preemption disabled.. so it is safe to use __ versions */ |
285 | static inline void set_kprobe_instance(struct kprobe *kp) | |
286 | { | |
b76834bc | 287 | __this_cpu_write(kprobe_instance, kp); |
e6584523 AM |
288 | } |
289 | ||
290 | static inline void reset_kprobe_instance(void) | |
291 | { | |
b76834bc | 292 | __this_cpu_write(kprobe_instance, NULL); |
e6584523 AM |
293 | } |
294 | ||
3516a460 AM |
295 | /* |
296 | * This routine is called either: | |
49a2a1b8 | 297 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 298 | * OR |
d217d545 | 299 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 300 | */ |
d0aaff97 | 301 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
302 | { |
303 | struct hlist_head *head; | |
3516a460 | 304 | struct kprobe *p; |
1da177e4 LT |
305 | |
306 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
b67bfe0d | 307 | hlist_for_each_entry_rcu(p, head, hlist) { |
1da177e4 LT |
308 | if (p->addr == addr) |
309 | return p; | |
310 | } | |
afd66255 | 311 | |
1da177e4 LT |
312 | return NULL; |
313 | } | |
314 | ||
afd66255 MH |
315 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
316 | ||
317 | /* Return true if the kprobe is an aggregator */ | |
318 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
319 | { | |
320 | return p->pre_handler == aggr_pre_handler; | |
321 | } | |
322 | ||
6274de49 MH |
323 | /* Return true(!0) if the kprobe is unused */ |
324 | static inline int kprobe_unused(struct kprobe *p) | |
325 | { | |
326 | return kprobe_aggrprobe(p) && kprobe_disabled(p) && | |
327 | list_empty(&p->list); | |
328 | } | |
329 | ||
afd66255 MH |
330 | /* |
331 | * Keep all fields in the kprobe consistent | |
332 | */ | |
6d8e40a8 | 333 | static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
afd66255 | 334 | { |
6d8e40a8 MH |
335 | memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); |
336 | memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); | |
afd66255 MH |
337 | } |
338 | ||
339 | #ifdef CONFIG_OPTPROBES | |
b2be84df MH |
340 | /* NOTE: change this value only with kprobe_mutex held */ |
341 | static bool kprobes_allow_optimization; | |
342 | ||
afd66255 MH |
343 | /* |
344 | * Call all pre_handler on the list, but ignores its return value. | |
345 | * This must be called from arch-dep optimized caller. | |
346 | */ | |
347 | void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
348 | { | |
349 | struct kprobe *kp; | |
350 | ||
351 | list_for_each_entry_rcu(kp, &p->list, list) { | |
352 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
353 | set_kprobe_instance(kp); | |
354 | kp->pre_handler(kp, regs); | |
355 | } | |
356 | reset_kprobe_instance(); | |
357 | } | |
358 | } | |
359 | ||
6274de49 MH |
360 | /* Free optimized instructions and optimized_kprobe */ |
361 | static __kprobes void free_aggr_kprobe(struct kprobe *p) | |
362 | { | |
363 | struct optimized_kprobe *op; | |
364 | ||
365 | op = container_of(p, struct optimized_kprobe, kp); | |
366 | arch_remove_optimized_kprobe(op); | |
367 | arch_remove_kprobe(p); | |
368 | kfree(op); | |
369 | } | |
370 | ||
afd66255 MH |
371 | /* Return true(!0) if the kprobe is ready for optimization. */ |
372 | static inline int kprobe_optready(struct kprobe *p) | |
373 | { | |
374 | struct optimized_kprobe *op; | |
375 | ||
376 | if (kprobe_aggrprobe(p)) { | |
377 | op = container_of(p, struct optimized_kprobe, kp); | |
378 | return arch_prepared_optinsn(&op->optinsn); | |
379 | } | |
380 | ||
381 | return 0; | |
382 | } | |
383 | ||
6274de49 MH |
384 | /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ |
385 | static inline int kprobe_disarmed(struct kprobe *p) | |
386 | { | |
387 | struct optimized_kprobe *op; | |
388 | ||
389 | /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ | |
390 | if (!kprobe_aggrprobe(p)) | |
391 | return kprobe_disabled(p); | |
392 | ||
393 | op = container_of(p, struct optimized_kprobe, kp); | |
394 | ||
395 | return kprobe_disabled(p) && list_empty(&op->list); | |
396 | } | |
397 | ||
398 | /* Return true(!0) if the probe is queued on (un)optimizing lists */ | |
399 | static int __kprobes kprobe_queued(struct kprobe *p) | |
400 | { | |
401 | struct optimized_kprobe *op; | |
402 | ||
403 | if (kprobe_aggrprobe(p)) { | |
404 | op = container_of(p, struct optimized_kprobe, kp); | |
405 | if (!list_empty(&op->list)) | |
406 | return 1; | |
407 | } | |
408 | return 0; | |
409 | } | |
410 | ||
afd66255 MH |
411 | /* |
412 | * Return an optimized kprobe whose optimizing code replaces | |
413 | * instructions including addr (exclude breakpoint). | |
414 | */ | |
6376b229 | 415 | static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) |
afd66255 MH |
416 | { |
417 | int i; | |
418 | struct kprobe *p = NULL; | |
419 | struct optimized_kprobe *op; | |
420 | ||
421 | /* Don't check i == 0, since that is a breakpoint case. */ | |
422 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
423 | p = get_kprobe((void *)(addr - i)); | |
424 | ||
425 | if (p && kprobe_optready(p)) { | |
426 | op = container_of(p, struct optimized_kprobe, kp); | |
427 | if (arch_within_optimized_kprobe(op, addr)) | |
428 | return p; | |
429 | } | |
430 | ||
431 | return NULL; | |
432 | } | |
433 | ||
434 | /* Optimization staging list, protected by kprobe_mutex */ | |
435 | static LIST_HEAD(optimizing_list); | |
6274de49 | 436 | static LIST_HEAD(unoptimizing_list); |
7b959fc5 | 437 | static LIST_HEAD(freeing_list); |
afd66255 MH |
438 | |
439 | static void kprobe_optimizer(struct work_struct *work); | |
440 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
441 | #define OPTIMIZE_DELAY 5 | |
442 | ||
61f4e13f MH |
443 | /* |
444 | * Optimize (replace a breakpoint with a jump) kprobes listed on | |
445 | * optimizing_list. | |
446 | */ | |
447 | static __kprobes void do_optimize_kprobes(void) | |
afd66255 | 448 | { |
6274de49 MH |
449 | /* Optimization never be done when disarmed */ |
450 | if (kprobes_all_disarmed || !kprobes_allow_optimization || | |
451 | list_empty(&optimizing_list)) | |
452 | return; | |
453 | ||
afd66255 MH |
454 | /* |
455 | * The optimization/unoptimization refers online_cpus via | |
456 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
457 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
458 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
459 | * text_mutex but stop_machine can not be done because online_cpus | |
460 | * has been changed) | |
461 | * To avoid this deadlock, we need to call get_online_cpus() | |
462 | * for preventing cpu-hotplug outside of text_mutex locking. | |
463 | */ | |
464 | get_online_cpus(); | |
465 | mutex_lock(&text_mutex); | |
cd7ebe22 | 466 | arch_optimize_kprobes(&optimizing_list); |
afd66255 MH |
467 | mutex_unlock(&text_mutex); |
468 | put_online_cpus(); | |
61f4e13f MH |
469 | } |
470 | ||
6274de49 MH |
471 | /* |
472 | * Unoptimize (replace a jump with a breakpoint and remove the breakpoint | |
473 | * if need) kprobes listed on unoptimizing_list. | |
474 | */ | |
7b959fc5 | 475 | static __kprobes void do_unoptimize_kprobes(void) |
6274de49 MH |
476 | { |
477 | struct optimized_kprobe *op, *tmp; | |
478 | ||
479 | /* Unoptimization must be done anytime */ | |
480 | if (list_empty(&unoptimizing_list)) | |
481 | return; | |
482 | ||
483 | /* Ditto to do_optimize_kprobes */ | |
484 | get_online_cpus(); | |
485 | mutex_lock(&text_mutex); | |
7b959fc5 | 486 | arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
f984ba4e | 487 | /* Loop free_list for disarming */ |
7b959fc5 | 488 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 MH |
489 | /* Disarm probes if marked disabled */ |
490 | if (kprobe_disabled(&op->kp)) | |
491 | arch_disarm_kprobe(&op->kp); | |
492 | if (kprobe_unused(&op->kp)) { | |
493 | /* | |
494 | * Remove unused probes from hash list. After waiting | |
495 | * for synchronization, these probes are reclaimed. | |
496 | * (reclaiming is done by do_free_cleaned_kprobes.) | |
497 | */ | |
498 | hlist_del_rcu(&op->kp.hlist); | |
6274de49 MH |
499 | } else |
500 | list_del_init(&op->list); | |
501 | } | |
502 | mutex_unlock(&text_mutex); | |
503 | put_online_cpus(); | |
504 | } | |
505 | ||
506 | /* Reclaim all kprobes on the free_list */ | |
7b959fc5 | 507 | static __kprobes void do_free_cleaned_kprobes(void) |
6274de49 MH |
508 | { |
509 | struct optimized_kprobe *op, *tmp; | |
510 | ||
7b959fc5 | 511 | list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de49 MH |
512 | BUG_ON(!kprobe_unused(&op->kp)); |
513 | list_del_init(&op->list); | |
514 | free_aggr_kprobe(&op->kp); | |
515 | } | |
516 | } | |
517 | ||
518 | /* Start optimizer after OPTIMIZE_DELAY passed */ | |
519 | static __kprobes void kick_kprobe_optimizer(void) | |
520 | { | |
ad72b3be | 521 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de49 MH |
522 | } |
523 | ||
61f4e13f MH |
524 | /* Kprobe jump optimizer */ |
525 | static __kprobes void kprobe_optimizer(struct work_struct *work) | |
526 | { | |
72ef3794 | 527 | mutex_lock(&kprobe_mutex); |
61f4e13f MH |
528 | /* Lock modules while optimizing kprobes */ |
529 | mutex_lock(&module_mutex); | |
61f4e13f MH |
530 | |
531 | /* | |
6274de49 MH |
532 | * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) |
533 | * kprobes before waiting for quiesence period. | |
534 | */ | |
7b959fc5 | 535 | do_unoptimize_kprobes(); |
6274de49 MH |
536 | |
537 | /* | |
538 | * Step 2: Wait for quiesence period to ensure all running interrupts | |
61f4e13f MH |
539 | * are done. Because optprobe may modify multiple instructions |
540 | * there is a chance that Nth instruction is interrupted. In that | |
541 | * case, running interrupt can return to 2nd-Nth byte of jump | |
542 | * instruction. This wait is for avoiding it. | |
543 | */ | |
544 | synchronize_sched(); | |
545 | ||
6274de49 | 546 | /* Step 3: Optimize kprobes after quiesence period */ |
61f4e13f | 547 | do_optimize_kprobes(); |
6274de49 MH |
548 | |
549 | /* Step 4: Free cleaned kprobes after quiesence period */ | |
7b959fc5 | 550 | do_free_cleaned_kprobes(); |
6274de49 | 551 | |
afd66255 | 552 | mutex_unlock(&module_mutex); |
72ef3794 | 553 | mutex_unlock(&kprobe_mutex); |
6274de49 | 554 | |
cd7ebe22 | 555 | /* Step 5: Kick optimizer again if needed */ |
f984ba4e | 556 | if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe22 | 557 | kick_kprobe_optimizer(); |
6274de49 MH |
558 | } |
559 | ||
560 | /* Wait for completing optimization and unoptimization */ | |
561 | static __kprobes void wait_for_kprobe_optimizer(void) | |
562 | { | |
ad72b3be TH |
563 | mutex_lock(&kprobe_mutex); |
564 | ||
565 | while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { | |
566 | mutex_unlock(&kprobe_mutex); | |
567 | ||
568 | /* this will also make optimizing_work execute immmediately */ | |
569 | flush_delayed_work(&optimizing_work); | |
570 | /* @optimizing_work might not have been queued yet, relax */ | |
571 | cpu_relax(); | |
572 | ||
573 | mutex_lock(&kprobe_mutex); | |
574 | } | |
575 | ||
576 | mutex_unlock(&kprobe_mutex); | |
afd66255 MH |
577 | } |
578 | ||
579 | /* Optimize kprobe if p is ready to be optimized */ | |
580 | static __kprobes void optimize_kprobe(struct kprobe *p) | |
581 | { | |
582 | struct optimized_kprobe *op; | |
583 | ||
584 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
b2be84df | 585 | if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255 MH |
586 | (kprobe_disabled(p) || kprobes_all_disarmed)) |
587 | return; | |
588 | ||
589 | /* Both of break_handler and post_handler are not supported. */ | |
590 | if (p->break_handler || p->post_handler) | |
591 | return; | |
592 | ||
593 | op = container_of(p, struct optimized_kprobe, kp); | |
594 | ||
595 | /* Check there is no other kprobes at the optimized instructions */ | |
596 | if (arch_check_optimized_kprobe(op) < 0) | |
597 | return; | |
598 | ||
599 | /* Check if it is already optimized. */ | |
600 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) | |
601 | return; | |
afd66255 | 602 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de49 MH |
603 | |
604 | if (!list_empty(&op->list)) | |
605 | /* This is under unoptimizing. Just dequeue the probe */ | |
606 | list_del_init(&op->list); | |
607 | else { | |
608 | list_add(&op->list, &optimizing_list); | |
609 | kick_kprobe_optimizer(); | |
610 | } | |
611 | } | |
612 | ||
613 | /* Short cut to direct unoptimizing */ | |
614 | static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op) | |
615 | { | |
616 | get_online_cpus(); | |
617 | arch_unoptimize_kprobe(op); | |
618 | put_online_cpus(); | |
619 | if (kprobe_disabled(&op->kp)) | |
620 | arch_disarm_kprobe(&op->kp); | |
afd66255 MH |
621 | } |
622 | ||
623 | /* Unoptimize a kprobe if p is optimized */ | |
6274de49 | 624 | static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255 MH |
625 | { |
626 | struct optimized_kprobe *op; | |
627 | ||
6274de49 MH |
628 | if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) |
629 | return; /* This is not an optprobe nor optimized */ | |
630 | ||
631 | op = container_of(p, struct optimized_kprobe, kp); | |
632 | if (!kprobe_optimized(p)) { | |
633 | /* Unoptimized or unoptimizing case */ | |
634 | if (force && !list_empty(&op->list)) { | |
635 | /* | |
636 | * Only if this is unoptimizing kprobe and forced, | |
637 | * forcibly unoptimize it. (No need to unoptimize | |
638 | * unoptimized kprobe again :) | |
639 | */ | |
afd66255 | 640 | list_del_init(&op->list); |
6274de49 MH |
641 | force_unoptimize_kprobe(op); |
642 | } | |
643 | return; | |
644 | } | |
645 | ||
646 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
647 | if (!list_empty(&op->list)) { | |
648 | /* Dequeue from the optimization queue */ | |
649 | list_del_init(&op->list); | |
650 | return; | |
651 | } | |
652 | /* Optimized kprobe case */ | |
653 | if (force) | |
654 | /* Forcibly update the code: this is a special case */ | |
655 | force_unoptimize_kprobe(op); | |
656 | else { | |
657 | list_add(&op->list, &unoptimizing_list); | |
658 | kick_kprobe_optimizer(); | |
afd66255 MH |
659 | } |
660 | } | |
661 | ||
0490cd1f MH |
662 | /* Cancel unoptimizing for reusing */ |
663 | static void reuse_unused_kprobe(struct kprobe *ap) | |
664 | { | |
665 | struct optimized_kprobe *op; | |
666 | ||
667 | BUG_ON(!kprobe_unused(ap)); | |
668 | /* | |
669 | * Unused kprobe MUST be on the way of delayed unoptimizing (means | |
670 | * there is still a relative jump) and disabled. | |
671 | */ | |
672 | op = container_of(ap, struct optimized_kprobe, kp); | |
673 | if (unlikely(list_empty(&op->list))) | |
674 | printk(KERN_WARNING "Warning: found a stray unused " | |
675 | "aggrprobe@%p\n", ap->addr); | |
676 | /* Enable the probe again */ | |
677 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
678 | /* Optimize it again (remove from op->list) */ | |
679 | BUG_ON(!kprobe_optready(ap)); | |
680 | optimize_kprobe(ap); | |
681 | } | |
682 | ||
afd66255 MH |
683 | /* Remove optimized instructions */ |
684 | static void __kprobes kill_optimized_kprobe(struct kprobe *p) | |
685 | { | |
686 | struct optimized_kprobe *op; | |
687 | ||
688 | op = container_of(p, struct optimized_kprobe, kp); | |
6274de49 MH |
689 | if (!list_empty(&op->list)) |
690 | /* Dequeue from the (un)optimization queue */ | |
afd66255 | 691 | list_del_init(&op->list); |
6274de49 | 692 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc5 MH |
693 | |
694 | if (kprobe_unused(p)) { | |
695 | /* Enqueue if it is unused */ | |
696 | list_add(&op->list, &freeing_list); | |
697 | /* | |
698 | * Remove unused probes from the hash list. After waiting | |
699 | * for synchronization, this probe is reclaimed. | |
700 | * (reclaiming is done by do_free_cleaned_kprobes().) | |
701 | */ | |
702 | hlist_del_rcu(&op->kp.hlist); | |
703 | } | |
704 | ||
6274de49 | 705 | /* Don't touch the code, because it is already freed. */ |
afd66255 MH |
706 | arch_remove_optimized_kprobe(op); |
707 | } | |
708 | ||
709 | /* Try to prepare optimized instructions */ | |
710 | static __kprobes void prepare_optimized_kprobe(struct kprobe *p) | |
711 | { | |
712 | struct optimized_kprobe *op; | |
713 | ||
714 | op = container_of(p, struct optimized_kprobe, kp); | |
715 | arch_prepare_optimized_kprobe(op); | |
716 | } | |
717 | ||
afd66255 MH |
718 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
719 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
720 | { | |
721 | struct optimized_kprobe *op; | |
722 | ||
723 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
724 | if (!op) | |
725 | return NULL; | |
726 | ||
727 | INIT_LIST_HEAD(&op->list); | |
728 | op->kp.addr = p->addr; | |
729 | arch_prepare_optimized_kprobe(op); | |
730 | ||
731 | return &op->kp; | |
732 | } | |
733 | ||
734 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); | |
735 | ||
736 | /* | |
737 | * Prepare an optimized_kprobe and optimize it | |
738 | * NOTE: p must be a normal registered kprobe | |
739 | */ | |
740 | static __kprobes void try_to_optimize_kprobe(struct kprobe *p) | |
741 | { | |
742 | struct kprobe *ap; | |
743 | struct optimized_kprobe *op; | |
744 | ||
ae6aa16f MH |
745 | /* Impossible to optimize ftrace-based kprobe */ |
746 | if (kprobe_ftrace(p)) | |
747 | return; | |
748 | ||
25764288 MH |
749 | /* For preparing optimization, jump_label_text_reserved() is called */ |
750 | jump_label_lock(); | |
751 | mutex_lock(&text_mutex); | |
752 | ||
afd66255 MH |
753 | ap = alloc_aggr_kprobe(p); |
754 | if (!ap) | |
25764288 | 755 | goto out; |
afd66255 MH |
756 | |
757 | op = container_of(ap, struct optimized_kprobe, kp); | |
758 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
759 | /* If failed to setup optimizing, fallback to kprobe */ | |
6274de49 MH |
760 | arch_remove_optimized_kprobe(op); |
761 | kfree(op); | |
25764288 | 762 | goto out; |
afd66255 MH |
763 | } |
764 | ||
765 | init_aggr_kprobe(ap, p); | |
25764288 MH |
766 | optimize_kprobe(ap); /* This just kicks optimizer thread */ |
767 | ||
768 | out: | |
769 | mutex_unlock(&text_mutex); | |
770 | jump_label_unlock(); | |
afd66255 MH |
771 | } |
772 | ||
b2be84df MH |
773 | #ifdef CONFIG_SYSCTL |
774 | static void __kprobes optimize_all_kprobes(void) | |
775 | { | |
776 | struct hlist_head *head; | |
b2be84df MH |
777 | struct kprobe *p; |
778 | unsigned int i; | |
779 | ||
5c51543b | 780 | mutex_lock(&kprobe_mutex); |
b2be84df MH |
781 | /* If optimization is already allowed, just return */ |
782 | if (kprobes_allow_optimization) | |
5c51543b | 783 | goto out; |
b2be84df MH |
784 | |
785 | kprobes_allow_optimization = true; | |
b2be84df MH |
786 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
787 | head = &kprobe_table[i]; | |
b67bfe0d | 788 | hlist_for_each_entry_rcu(p, head, hlist) |
b2be84df MH |
789 | if (!kprobe_disabled(p)) |
790 | optimize_kprobe(p); | |
791 | } | |
b2be84df | 792 | printk(KERN_INFO "Kprobes globally optimized\n"); |
5c51543b MH |
793 | out: |
794 | mutex_unlock(&kprobe_mutex); | |
b2be84df MH |
795 | } |
796 | ||
797 | static void __kprobes unoptimize_all_kprobes(void) | |
798 | { | |
799 | struct hlist_head *head; | |
b2be84df MH |
800 | struct kprobe *p; |
801 | unsigned int i; | |
802 | ||
5c51543b | 803 | mutex_lock(&kprobe_mutex); |
b2be84df | 804 | /* If optimization is already prohibited, just return */ |
5c51543b MH |
805 | if (!kprobes_allow_optimization) { |
806 | mutex_unlock(&kprobe_mutex); | |
b2be84df | 807 | return; |
5c51543b | 808 | } |
b2be84df MH |
809 | |
810 | kprobes_allow_optimization = false; | |
b2be84df MH |
811 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
812 | head = &kprobe_table[i]; | |
b67bfe0d | 813 | hlist_for_each_entry_rcu(p, head, hlist) { |
b2be84df | 814 | if (!kprobe_disabled(p)) |
6274de49 | 815 | unoptimize_kprobe(p, false); |
b2be84df MH |
816 | } |
817 | } | |
5c51543b MH |
818 | mutex_unlock(&kprobe_mutex); |
819 | ||
6274de49 MH |
820 | /* Wait for unoptimizing completion */ |
821 | wait_for_kprobe_optimizer(); | |
822 | printk(KERN_INFO "Kprobes globally unoptimized\n"); | |
b2be84df MH |
823 | } |
824 | ||
5c51543b | 825 | static DEFINE_MUTEX(kprobe_sysctl_mutex); |
b2be84df MH |
826 | int sysctl_kprobes_optimization; |
827 | int proc_kprobes_optimization_handler(struct ctl_table *table, int write, | |
828 | void __user *buffer, size_t *length, | |
829 | loff_t *ppos) | |
830 | { | |
831 | int ret; | |
832 | ||
5c51543b | 833 | mutex_lock(&kprobe_sysctl_mutex); |
b2be84df MH |
834 | sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; |
835 | ret = proc_dointvec_minmax(table, write, buffer, length, ppos); | |
836 | ||
837 | if (sysctl_kprobes_optimization) | |
838 | optimize_all_kprobes(); | |
839 | else | |
840 | unoptimize_all_kprobes(); | |
5c51543b | 841 | mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df MH |
842 | |
843 | return ret; | |
844 | } | |
845 | #endif /* CONFIG_SYSCTL */ | |
846 | ||
6274de49 | 847 | /* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
afd66255 MH |
848 | static void __kprobes __arm_kprobe(struct kprobe *p) |
849 | { | |
6d8e40a8 | 850 | struct kprobe *_p; |
afd66255 MH |
851 | |
852 | /* Check collision with other optimized kprobes */ | |
6d8e40a8 MH |
853 | _p = get_optimized_kprobe((unsigned long)p->addr); |
854 | if (unlikely(_p)) | |
6274de49 MH |
855 | /* Fallback to unoptimized kprobe */ |
856 | unoptimize_kprobe(_p, true); | |
afd66255 MH |
857 | |
858 | arch_arm_kprobe(p); | |
859 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
860 | } | |
861 | ||
6274de49 MH |
862 | /* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
863 | static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt) | |
afd66255 | 864 | { |
6d8e40a8 | 865 | struct kprobe *_p; |
afd66255 | 866 | |
6274de49 | 867 | unoptimize_kprobe(p, false); /* Try to unoptimize */ |
afd66255 | 868 | |
6274de49 MH |
869 | if (!kprobe_queued(p)) { |
870 | arch_disarm_kprobe(p); | |
871 | /* If another kprobe was blocked, optimize it. */ | |
872 | _p = get_optimized_kprobe((unsigned long)p->addr); | |
873 | if (unlikely(_p) && reopt) | |
874 | optimize_kprobe(_p); | |
875 | } | |
876 | /* TODO: reoptimize others after unoptimized this probe */ | |
afd66255 MH |
877 | } |
878 | ||
879 | #else /* !CONFIG_OPTPROBES */ | |
880 | ||
881 | #define optimize_kprobe(p) do {} while (0) | |
6274de49 | 882 | #define unoptimize_kprobe(p, f) do {} while (0) |
afd66255 MH |
883 | #define kill_optimized_kprobe(p) do {} while (0) |
884 | #define prepare_optimized_kprobe(p) do {} while (0) | |
885 | #define try_to_optimize_kprobe(p) do {} while (0) | |
886 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
6274de49 MH |
887 | #define __disarm_kprobe(p, o) arch_disarm_kprobe(p) |
888 | #define kprobe_disarmed(p) kprobe_disabled(p) | |
889 | #define wait_for_kprobe_optimizer() do {} while (0) | |
afd66255 | 890 | |
0490cd1f MH |
891 | /* There should be no unused kprobes can be reused without optimization */ |
892 | static void reuse_unused_kprobe(struct kprobe *ap) | |
893 | { | |
894 | printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); | |
895 | BUG_ON(kprobe_unused(ap)); | |
896 | } | |
897 | ||
afd66255 MH |
898 | static __kprobes void free_aggr_kprobe(struct kprobe *p) |
899 | { | |
6274de49 | 900 | arch_remove_kprobe(p); |
afd66255 MH |
901 | kfree(p); |
902 | } | |
903 | ||
904 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
905 | { | |
906 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
907 | } | |
908 | #endif /* CONFIG_OPTPROBES */ | |
909 | ||
e7dbfe34 | 910 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f | 911 | static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
e5253896 | 912 | .func = kprobe_ftrace_handler, |
ae6aa16f MH |
913 | .flags = FTRACE_OPS_FL_SAVE_REGS, |
914 | }; | |
915 | static int kprobe_ftrace_enabled; | |
916 | ||
917 | /* Must ensure p->addr is really on ftrace */ | |
918 | static int __kprobes prepare_kprobe(struct kprobe *p) | |
919 | { | |
920 | if (!kprobe_ftrace(p)) | |
921 | return arch_prepare_kprobe(p); | |
922 | ||
923 | return arch_prepare_kprobe_ftrace(p); | |
924 | } | |
925 | ||
926 | /* Caller must lock kprobe_mutex */ | |
927 | static void __kprobes arm_kprobe_ftrace(struct kprobe *p) | |
928 | { | |
929 | int ret; | |
930 | ||
931 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
932 | (unsigned long)p->addr, 0, 0); | |
933 | WARN(ret < 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
934 | kprobe_ftrace_enabled++; | |
935 | if (kprobe_ftrace_enabled == 1) { | |
936 | ret = register_ftrace_function(&kprobe_ftrace_ops); | |
937 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
938 | } | |
939 | } | |
940 | ||
941 | /* Caller must lock kprobe_mutex */ | |
942 | static void __kprobes disarm_kprobe_ftrace(struct kprobe *p) | |
943 | { | |
944 | int ret; | |
945 | ||
946 | kprobe_ftrace_enabled--; | |
947 | if (kprobe_ftrace_enabled == 0) { | |
948 | ret = unregister_ftrace_function(&kprobe_ftrace_ops); | |
949 | WARN(ret < 0, "Failed to init kprobe-ftrace (%d)\n", ret); | |
950 | } | |
951 | ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, | |
952 | (unsigned long)p->addr, 1, 0); | |
953 | WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret); | |
954 | } | |
e7dbfe34 | 955 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
956 | #define prepare_kprobe(p) arch_prepare_kprobe(p) |
957 | #define arm_kprobe_ftrace(p) do {} while (0) | |
958 | #define disarm_kprobe_ftrace(p) do {} while (0) | |
959 | #endif | |
960 | ||
201517a7 MH |
961 | /* Arm a kprobe with text_mutex */ |
962 | static void __kprobes arm_kprobe(struct kprobe *kp) | |
963 | { | |
ae6aa16f MH |
964 | if (unlikely(kprobe_ftrace(kp))) { |
965 | arm_kprobe_ftrace(kp); | |
966 | return; | |
967 | } | |
afd66255 MH |
968 | /* |
969 | * Here, since __arm_kprobe() doesn't use stop_machine(), | |
970 | * this doesn't cause deadlock on text_mutex. So, we don't | |
971 | * need get_online_cpus(). | |
972 | */ | |
201517a7 | 973 | mutex_lock(&text_mutex); |
afd66255 | 974 | __arm_kprobe(kp); |
201517a7 MH |
975 | mutex_unlock(&text_mutex); |
976 | } | |
977 | ||
978 | /* Disarm a kprobe with text_mutex */ | |
ae6aa16f | 979 | static void __kprobes disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7 | 980 | { |
ae6aa16f MH |
981 | if (unlikely(kprobe_ftrace(kp))) { |
982 | disarm_kprobe_ftrace(kp); | |
983 | return; | |
984 | } | |
6274de49 | 985 | /* Ditto */ |
201517a7 | 986 | mutex_lock(&text_mutex); |
ae6aa16f | 987 | __disarm_kprobe(kp, reopt); |
201517a7 MH |
988 | mutex_unlock(&text_mutex); |
989 | } | |
990 | ||
64f562c6 AM |
991 | /* |
992 | * Aggregate handlers for multiple kprobes support - these handlers | |
993 | * take care of invoking the individual kprobe handlers on p->list | |
994 | */ | |
d0aaff97 | 995 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
996 | { |
997 | struct kprobe *kp; | |
998 | ||
3516a460 | 999 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1000 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1001 | set_kprobe_instance(kp); |
8b0914ea PP |
1002 | if (kp->pre_handler(kp, regs)) |
1003 | return 1; | |
64f562c6 | 1004 | } |
e6584523 | 1005 | reset_kprobe_instance(); |
64f562c6 AM |
1006 | } |
1007 | return 0; | |
1008 | } | |
1009 | ||
d0aaff97 PP |
1010 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
1011 | unsigned long flags) | |
64f562c6 AM |
1012 | { |
1013 | struct kprobe *kp; | |
1014 | ||
3516a460 | 1015 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 1016 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 1017 | set_kprobe_instance(kp); |
64f562c6 | 1018 | kp->post_handler(kp, regs, flags); |
e6584523 | 1019 | reset_kprobe_instance(); |
64f562c6 AM |
1020 | } |
1021 | } | |
64f562c6 AM |
1022 | } |
1023 | ||
d0aaff97 PP |
1024 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
1025 | int trapnr) | |
64f562c6 | 1026 | { |
b76834bc | 1027 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 | 1028 | |
64f562c6 AM |
1029 | /* |
1030 | * if we faulted "during" the execution of a user specified | |
1031 | * probe handler, invoke just that probe's fault handler | |
1032 | */ | |
e6584523 AM |
1033 | if (cur && cur->fault_handler) { |
1034 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
1035 | return 1; |
1036 | } | |
1037 | return 0; | |
1038 | } | |
1039 | ||
d0aaff97 | 1040 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 1041 | { |
b76834bc | 1042 | struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e6584523 AM |
1043 | int ret = 0; |
1044 | ||
1045 | if (cur && cur->break_handler) { | |
1046 | if (cur->break_handler(cur, regs)) | |
1047 | ret = 1; | |
8b0914ea | 1048 | } |
e6584523 AM |
1049 | reset_kprobe_instance(); |
1050 | return ret; | |
8b0914ea PP |
1051 | } |
1052 | ||
bf8d5c52 KA |
1053 | /* Walks the list and increments nmissed count for multiprobe case */ |
1054 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
1055 | { | |
1056 | struct kprobe *kp; | |
afd66255 | 1057 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
1058 | p->nmissed++; |
1059 | } else { | |
1060 | list_for_each_entry_rcu(kp, &p->list, list) | |
1061 | kp->nmissed++; | |
1062 | } | |
1063 | return; | |
1064 | } | |
1065 | ||
99219a3f | 1066 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
1067 | struct hlist_head *head) | |
b94cce92 | 1068 | { |
ef53d9c5 S |
1069 | struct kretprobe *rp = ri->rp; |
1070 | ||
b94cce92 HN |
1071 | /* remove rp inst off the rprobe_inst_table */ |
1072 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
1073 | INIT_HLIST_NODE(&ri->hlist); |
1074 | if (likely(rp)) { | |
ec484608 | 1075 | raw_spin_lock(&rp->lock); |
ef53d9c5 | 1076 | hlist_add_head(&ri->hlist, &rp->free_instances); |
ec484608 | 1077 | raw_spin_unlock(&rp->lock); |
b94cce92 HN |
1078 | } else |
1079 | /* Unregistering */ | |
99219a3f | 1080 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
1081 | } |
1082 | ||
017c39bd | 1083 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 | 1084 | struct hlist_head **head, unsigned long *flags) |
635c17c2 | 1085 | __acquires(hlist_lock) |
ef53d9c5 S |
1086 | { |
1087 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1088 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1089 | |
1090 | *head = &kretprobe_inst_table[hash]; | |
1091 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1092 | raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5 S |
1093 | } |
1094 | ||
017c39bd MH |
1095 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
1096 | unsigned long *flags) | |
635c17c2 | 1097 | __acquires(hlist_lock) |
b94cce92 | 1098 | { |
ec484608 TG |
1099 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1100 | raw_spin_lock_irqsave(hlist_lock, *flags); | |
ef53d9c5 S |
1101 | } |
1102 | ||
017c39bd MH |
1103 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
1104 | unsigned long *flags) | |
635c17c2 | 1105 | __releases(hlist_lock) |
ef53d9c5 S |
1106 | { |
1107 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
ec484608 | 1108 | raw_spinlock_t *hlist_lock; |
ef53d9c5 S |
1109 | |
1110 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
ec484608 | 1111 | raw_spin_unlock_irqrestore(hlist_lock, *flags); |
ef53d9c5 S |
1112 | } |
1113 | ||
6376b229 NK |
1114 | static void __kprobes kretprobe_table_unlock(unsigned long hash, |
1115 | unsigned long *flags) | |
635c17c2 | 1116 | __releases(hlist_lock) |
ef53d9c5 | 1117 | { |
ec484608 TG |
1118 | raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
1119 | raw_spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
1120 | } |
1121 | ||
b94cce92 | 1122 | /* |
c6fd91f0 | 1123 | * This function is called from finish_task_switch when task tk becomes dead, |
1124 | * so that we can recycle any function-return probe instances associated | |
1125 | * with this task. These left over instances represent probed functions | |
1126 | * that have been called but will never return. | |
b94cce92 | 1127 | */ |
d0aaff97 | 1128 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 1129 | { |
62c27be0 | 1130 | struct kretprobe_instance *ri; |
99219a3f | 1131 | struct hlist_head *head, empty_rp; |
b67bfe0d | 1132 | struct hlist_node *tmp; |
ef53d9c5 | 1133 | unsigned long hash, flags = 0; |
802eae7c | 1134 | |
ef53d9c5 S |
1135 | if (unlikely(!kprobes_initialized)) |
1136 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
1137 | return; | |
1138 | ||
d496aab5 | 1139 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 S |
1140 | hash = hash_ptr(tk, KPROBE_HASH_BITS); |
1141 | head = &kretprobe_inst_table[hash]; | |
1142 | kretprobe_table_lock(hash, &flags); | |
b67bfe0d | 1143 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
62c27be0 | 1144 | if (ri->task == tk) |
99219a3f | 1145 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 1146 | } |
ef53d9c5 | 1147 | kretprobe_table_unlock(hash, &flags); |
b67bfe0d | 1148 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
99219a3f | 1149 | hlist_del(&ri->hlist); |
1150 | kfree(ri); | |
1151 | } | |
b94cce92 HN |
1152 | } |
1153 | ||
b94cce92 HN |
1154 | static inline void free_rp_inst(struct kretprobe *rp) |
1155 | { | |
1156 | struct kretprobe_instance *ri; | |
b67bfe0d | 1157 | struct hlist_node *next; |
4c4308cb | 1158 | |
b67bfe0d | 1159 | hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) { |
ef53d9c5 | 1160 | hlist_del(&ri->hlist); |
b94cce92 HN |
1161 | kfree(ri); |
1162 | } | |
1163 | } | |
1164 | ||
4a296e07 MH |
1165 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
1166 | { | |
ef53d9c5 | 1167 | unsigned long flags, hash; |
4a296e07 | 1168 | struct kretprobe_instance *ri; |
b67bfe0d | 1169 | struct hlist_node *next; |
ef53d9c5 S |
1170 | struct hlist_head *head; |
1171 | ||
4a296e07 | 1172 | /* No race here */ |
ef53d9c5 S |
1173 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
1174 | kretprobe_table_lock(hash, &flags); | |
1175 | head = &kretprobe_inst_table[hash]; | |
b67bfe0d | 1176 | hlist_for_each_entry_safe(ri, next, head, hlist) { |
ef53d9c5 S |
1177 | if (ri->rp == rp) |
1178 | ri->rp = NULL; | |
1179 | } | |
1180 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 1181 | } |
4a296e07 MH |
1182 | free_rp_inst(rp); |
1183 | } | |
1184 | ||
8b0914ea | 1185 | /* |
b918e5e6 | 1186 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
1187 | * second jprobe at the address - two jprobes can't coexist |
1188 | */ | |
b918e5e6 | 1189 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 1190 | { |
de5bd88d | 1191 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
afd66255 MH |
1192 | |
1193 | if (p->break_handler || p->post_handler) | |
6274de49 | 1194 | unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255 | 1195 | |
8b0914ea | 1196 | if (p->break_handler) { |
b918e5e6 | 1197 | if (ap->break_handler) |
36721656 | 1198 | return -EEXIST; |
b918e5e6 MH |
1199 | list_add_tail_rcu(&p->list, &ap->list); |
1200 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 1201 | } else |
b918e5e6 MH |
1202 | list_add_rcu(&p->list, &ap->list); |
1203 | if (p->post_handler && !ap->post_handler) | |
1204 | ap->post_handler = aggr_post_handler; | |
de5bd88d | 1205 | |
8b0914ea PP |
1206 | return 0; |
1207 | } | |
1208 | ||
64f562c6 AM |
1209 | /* |
1210 | * Fill in the required fields of the "manager kprobe". Replace the | |
1211 | * earlier kprobe in the hlist with the manager kprobe | |
1212 | */ | |
afd66255 | 1213 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 1214 | { |
afd66255 | 1215 | /* Copy p's insn slot to ap */ |
8b0914ea | 1216 | copy_kprobe(p, ap); |
a9ad965e | 1217 | flush_insn_slot(ap); |
64f562c6 | 1218 | ap->addr = p->addr; |
afd66255 | 1219 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 1220 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 1221 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
1222 | /* We don't care the kprobe which has gone. */ |
1223 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 1224 | ap->post_handler = aggr_post_handler; |
e8386a0c | 1225 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 1226 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
1227 | |
1228 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 1229 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 1230 | |
afd66255 | 1231 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 1232 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
1233 | } |
1234 | ||
1235 | /* | |
1236 | * This is the second or subsequent kprobe at the address - handle | |
1237 | * the intricacies | |
64f562c6 | 1238 | */ |
6d8e40a8 | 1239 | static int __kprobes register_aggr_kprobe(struct kprobe *orig_p, |
d0aaff97 | 1240 | struct kprobe *p) |
64f562c6 AM |
1241 | { |
1242 | int ret = 0; | |
6d8e40a8 | 1243 | struct kprobe *ap = orig_p; |
64f562c6 | 1244 | |
25764288 MH |
1245 | /* For preparing optimization, jump_label_text_reserved() is called */ |
1246 | jump_label_lock(); | |
1247 | /* | |
1248 | * Get online CPUs to avoid text_mutex deadlock.with stop machine, | |
1249 | * which is invoked by unoptimize_kprobe() in add_new_kprobe() | |
1250 | */ | |
1251 | get_online_cpus(); | |
1252 | mutex_lock(&text_mutex); | |
1253 | ||
6d8e40a8 MH |
1254 | if (!kprobe_aggrprobe(orig_p)) { |
1255 | /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
1256 | ap = alloc_aggr_kprobe(orig_p); | |
25764288 MH |
1257 | if (!ap) { |
1258 | ret = -ENOMEM; | |
1259 | goto out; | |
1260 | } | |
6d8e40a8 | 1261 | init_aggr_kprobe(ap, orig_p); |
6274de49 | 1262 | } else if (kprobe_unused(ap)) |
0490cd1f MH |
1263 | /* This probe is going to die. Rescue it */ |
1264 | reuse_unused_kprobe(ap); | |
b918e5e6 MH |
1265 | |
1266 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
1267 | /* |
1268 | * Attempting to insert new probe at the same location that | |
1269 | * had a probe in the module vaddr area which already | |
1270 | * freed. So, the instruction slot has already been | |
1271 | * released. We need a new slot for the new probe. | |
1272 | */ | |
b918e5e6 | 1273 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 1274 | if (ret) |
b918e5e6 MH |
1275 | /* |
1276 | * Even if fail to allocate new slot, don't need to | |
1277 | * free aggr_probe. It will be used next time, or | |
1278 | * freed by unregister_kprobe. | |
1279 | */ | |
25764288 | 1280 | goto out; |
de5bd88d | 1281 | |
afd66255 MH |
1282 | /* Prepare optimized instructions if possible. */ |
1283 | prepare_optimized_kprobe(ap); | |
1284 | ||
e8386a0c | 1285 | /* |
de5bd88d MH |
1286 | * Clear gone flag to prevent allocating new slot again, and |
1287 | * set disabled flag because it is not armed yet. | |
e8386a0c | 1288 | */ |
de5bd88d MH |
1289 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
1290 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 1291 | } |
b918e5e6 | 1292 | |
afd66255 | 1293 | /* Copy ap's insn slot to p */ |
b918e5e6 | 1294 | copy_kprobe(ap, p); |
25764288 MH |
1295 | ret = add_new_kprobe(ap, p); |
1296 | ||
1297 | out: | |
1298 | mutex_unlock(&text_mutex); | |
1299 | put_online_cpus(); | |
1300 | jump_label_unlock(); | |
1301 | ||
1302 | if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
1303 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
1304 | if (!kprobes_all_disarmed) | |
1305 | /* Arm the breakpoint again. */ | |
1306 | arm_kprobe(ap); | |
1307 | } | |
1308 | return ret; | |
64f562c6 AM |
1309 | } |
1310 | ||
d0aaff97 PP |
1311 | static int __kprobes in_kprobes_functions(unsigned long addr) |
1312 | { | |
3d8d996e SD |
1313 | struct kprobe_blackpoint *kb; |
1314 | ||
6f716acd CH |
1315 | if (addr >= (unsigned long)__kprobes_text_start && |
1316 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 1317 | return -EINVAL; |
3d8d996e SD |
1318 | /* |
1319 | * If there exists a kprobe_blacklist, verify and | |
1320 | * fail any probe registration in the prohibited area | |
1321 | */ | |
1322 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1323 | if (kb->start_addr) { | |
1324 | if (addr >= kb->start_addr && | |
1325 | addr < (kb->start_addr + kb->range)) | |
1326 | return -EINVAL; | |
1327 | } | |
1328 | } | |
d0aaff97 PP |
1329 | return 0; |
1330 | } | |
1331 | ||
b2a5cd69 MH |
1332 | /* |
1333 | * If we have a symbol_name argument, look it up and add the offset field | |
1334 | * to it. This way, we can specify a relative address to a symbol. | |
bc81d48d MH |
1335 | * This returns encoded errors if it fails to look up symbol or invalid |
1336 | * combination of parameters. | |
b2a5cd69 MH |
1337 | */ |
1338 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
1339 | { | |
1340 | kprobe_opcode_t *addr = p->addr; | |
bc81d48d MH |
1341 | |
1342 | if ((p->symbol_name && p->addr) || | |
1343 | (!p->symbol_name && !p->addr)) | |
1344 | goto invalid; | |
1345 | ||
b2a5cd69 | 1346 | if (p->symbol_name) { |
b2a5cd69 | 1347 | kprobe_lookup_name(p->symbol_name, addr); |
bc81d48d MH |
1348 | if (!addr) |
1349 | return ERR_PTR(-ENOENT); | |
b2a5cd69 MH |
1350 | } |
1351 | ||
bc81d48d MH |
1352 | addr = (kprobe_opcode_t *)(((char *)addr) + p->offset); |
1353 | if (addr) | |
1354 | return addr; | |
1355 | ||
1356 | invalid: | |
1357 | return ERR_PTR(-EINVAL); | |
b2a5cd69 MH |
1358 | } |
1359 | ||
1f0ab409 AM |
1360 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1361 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) | |
1362 | { | |
6d8e40a8 | 1363 | struct kprobe *ap, *list_p; |
1f0ab409 | 1364 | |
6d8e40a8 MH |
1365 | ap = get_kprobe(p->addr); |
1366 | if (unlikely(!ap)) | |
1f0ab409 AM |
1367 | return NULL; |
1368 | ||
6d8e40a8 MH |
1369 | if (p != ap) { |
1370 | list_for_each_entry_rcu(list_p, &ap->list, list) | |
1f0ab409 AM |
1371 | if (list_p == p) |
1372 | /* kprobe p is a valid probe */ | |
1373 | goto valid; | |
1374 | return NULL; | |
1375 | } | |
1376 | valid: | |
6d8e40a8 | 1377 | return ap; |
1f0ab409 AM |
1378 | } |
1379 | ||
1380 | /* Return error if the kprobe is being re-registered */ | |
1381 | static inline int check_kprobe_rereg(struct kprobe *p) | |
1382 | { | |
1383 | int ret = 0; | |
1f0ab409 AM |
1384 | |
1385 | mutex_lock(&kprobe_mutex); | |
6d8e40a8 | 1386 | if (__get_valid_kprobe(p)) |
1f0ab409 AM |
1387 | ret = -EINVAL; |
1388 | mutex_unlock(&kprobe_mutex); | |
6d8e40a8 | 1389 | |
1f0ab409 AM |
1390 | return ret; |
1391 | } | |
1392 | ||
f7fa6ef0 MH |
1393 | static __kprobes int check_kprobe_address_safe(struct kprobe *p, |
1394 | struct module **probed_mod) | |
1da177e4 LT |
1395 | { |
1396 | int ret = 0; | |
ae6aa16f MH |
1397 | unsigned long ftrace_addr; |
1398 | ||
1399 | /* | |
1400 | * If the address is located on a ftrace nop, set the | |
1401 | * breakpoint to the following instruction. | |
1402 | */ | |
1403 | ftrace_addr = ftrace_location((unsigned long)p->addr); | |
1404 | if (ftrace_addr) { | |
e7dbfe34 | 1405 | #ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16f MH |
1406 | /* Given address is not on the instruction boundary */ |
1407 | if ((unsigned long)p->addr != ftrace_addr) | |
1408 | return -EILSEQ; | |
ae6aa16f | 1409 | p->flags |= KPROBE_FLAG_FTRACE; |
e7dbfe34 | 1410 | #else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16f MH |
1411 | return -EINVAL; |
1412 | #endif | |
1413 | } | |
1f0ab409 | 1414 | |
91bad2f8 | 1415 | jump_label_lock(); |
de31c3ca | 1416 | preempt_disable(); |
f7fa6ef0 MH |
1417 | |
1418 | /* Ensure it is not in reserved area nor out of text */ | |
ec30c5f3 | 1419 | if (!kernel_text_address((unsigned long) p->addr) || |
4554dbcb | 1420 | in_kprobes_functions((unsigned long) p->addr) || |
f986a499 PN |
1421 | jump_label_text_reserved(p->addr, p->addr)) { |
1422 | ret = -EINVAL; | |
f7fa6ef0 | 1423 | goto out; |
f986a499 | 1424 | } |
b3e55c72 | 1425 | |
f7fa6ef0 MH |
1426 | /* Check if are we probing a module */ |
1427 | *probed_mod = __module_text_address((unsigned long) p->addr); | |
1428 | if (*probed_mod) { | |
6f716acd | 1429 | /* |
e8386a0c MH |
1430 | * We must hold a refcount of the probed module while updating |
1431 | * its code to prohibit unexpected unloading. | |
df019b1d | 1432 | */ |
f7fa6ef0 MH |
1433 | if (unlikely(!try_module_get(*probed_mod))) { |
1434 | ret = -ENOENT; | |
1435 | goto out; | |
1436 | } | |
de31c3ca | 1437 | |
f24659d9 MH |
1438 | /* |
1439 | * If the module freed .init.text, we couldn't insert | |
1440 | * kprobes in there. | |
1441 | */ | |
f7fa6ef0 MH |
1442 | if (within_module_init((unsigned long)p->addr, *probed_mod) && |
1443 | (*probed_mod)->state != MODULE_STATE_COMING) { | |
1444 | module_put(*probed_mod); | |
1445 | *probed_mod = NULL; | |
1446 | ret = -ENOENT; | |
f24659d9 | 1447 | } |
df019b1d | 1448 | } |
f7fa6ef0 | 1449 | out: |
a189d035 | 1450 | preempt_enable(); |
de31c3ca | 1451 | jump_label_unlock(); |
1da177e4 | 1452 | |
f7fa6ef0 MH |
1453 | return ret; |
1454 | } | |
1455 | ||
1456 | int __kprobes register_kprobe(struct kprobe *p) | |
1457 | { | |
1458 | int ret; | |
1459 | struct kprobe *old_p; | |
1460 | struct module *probed_mod; | |
1461 | kprobe_opcode_t *addr; | |
1462 | ||
1463 | /* Adjust probe address from symbol */ | |
1464 | addr = kprobe_addr(p); | |
1465 | if (IS_ERR(addr)) | |
1466 | return PTR_ERR(addr); | |
1467 | p->addr = addr; | |
1468 | ||
1469 | ret = check_kprobe_rereg(p); | |
1470 | if (ret) | |
1471 | return ret; | |
1472 | ||
1473 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ | |
1474 | p->flags &= KPROBE_FLAG_DISABLED; | |
3516a460 | 1475 | p->nmissed = 0; |
9861668f | 1476 | INIT_LIST_HEAD(&p->list); |
afd66255 | 1477 | |
f7fa6ef0 MH |
1478 | ret = check_kprobe_address_safe(p, &probed_mod); |
1479 | if (ret) | |
1480 | return ret; | |
1481 | ||
1482 | mutex_lock(&kprobe_mutex); | |
afd66255 | 1483 | |
64f562c6 AM |
1484 | old_p = get_kprobe(p->addr); |
1485 | if (old_p) { | |
afd66255 | 1486 | /* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6 | 1487 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1488 | goto out; |
1489 | } | |
1da177e4 | 1490 | |
25764288 | 1491 | mutex_lock(&text_mutex); /* Avoiding text modification */ |
ae6aa16f | 1492 | ret = prepare_kprobe(p); |
25764288 | 1493 | mutex_unlock(&text_mutex); |
6f716acd | 1494 | if (ret) |
afd66255 | 1495 | goto out; |
49a2a1b8 | 1496 | |
64f562c6 | 1497 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1498 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1499 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1500 | ||
de5bd88d | 1501 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
25764288 | 1502 | arm_kprobe(p); |
afd66255 MH |
1503 | |
1504 | /* Try to optimize kprobe */ | |
1505 | try_to_optimize_kprobe(p); | |
74a0b576 | 1506 | |
1da177e4 | 1507 | out: |
7a7d1cf9 | 1508 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1509 | |
e8386a0c | 1510 | if (probed_mod) |
df019b1d | 1511 | module_put(probed_mod); |
e8386a0c | 1512 | |
1da177e4 LT |
1513 | return ret; |
1514 | } | |
99081ab5 | 1515 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1516 | |
6f0f1dd7 MH |
1517 | /* Check if all probes on the aggrprobe are disabled */ |
1518 | static int __kprobes aggr_kprobe_disabled(struct kprobe *ap) | |
1519 | { | |
1520 | struct kprobe *kp; | |
1521 | ||
1522 | list_for_each_entry_rcu(kp, &ap->list, list) | |
1523 | if (!kprobe_disabled(kp)) | |
1524 | /* | |
1525 | * There is an active probe on the list. | |
1526 | * We can't disable this ap. | |
1527 | */ | |
1528 | return 0; | |
1529 | ||
1530 | return 1; | |
1531 | } | |
1532 | ||
1533 | /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ | |
1534 | static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p) | |
1535 | { | |
1536 | struct kprobe *orig_p; | |
1537 | ||
1538 | /* Get an original kprobe for return */ | |
1539 | orig_p = __get_valid_kprobe(p); | |
1540 | if (unlikely(orig_p == NULL)) | |
1541 | return NULL; | |
1542 | ||
1543 | if (!kprobe_disabled(p)) { | |
1544 | /* Disable probe if it is a child probe */ | |
1545 | if (p != orig_p) | |
1546 | p->flags |= KPROBE_FLAG_DISABLED; | |
1547 | ||
1548 | /* Try to disarm and disable this/parent probe */ | |
1549 | if (p == orig_p || aggr_kprobe_disabled(orig_p)) { | |
ae6aa16f | 1550 | disarm_kprobe(orig_p, true); |
6f0f1dd7 MH |
1551 | orig_p->flags |= KPROBE_FLAG_DISABLED; |
1552 | } | |
1553 | } | |
1554 | ||
1555 | return orig_p; | |
1556 | } | |
1557 | ||
de5bd88d MH |
1558 | /* |
1559 | * Unregister a kprobe without a scheduler synchronization. | |
1560 | */ | |
1561 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1562 | { | |
6d8e40a8 | 1563 | struct kprobe *ap, *list_p; |
de5bd88d | 1564 | |
6f0f1dd7 MH |
1565 | /* Disable kprobe. This will disarm it if needed. */ |
1566 | ap = __disable_kprobe(p); | |
6d8e40a8 | 1567 | if (ap == NULL) |
de5bd88d MH |
1568 | return -EINVAL; |
1569 | ||
6f0f1dd7 | 1570 | if (ap == p) |
bf8f6e5b | 1571 | /* |
6f0f1dd7 MH |
1572 | * This probe is an independent(and non-optimized) kprobe |
1573 | * (not an aggrprobe). Remove from the hash list. | |
bf8f6e5b | 1574 | */ |
6f0f1dd7 MH |
1575 | goto disarmed; |
1576 | ||
1577 | /* Following process expects this probe is an aggrprobe */ | |
1578 | WARN_ON(!kprobe_aggrprobe(ap)); | |
1579 | ||
6274de49 MH |
1580 | if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) |
1581 | /* | |
1582 | * !disarmed could be happen if the probe is under delayed | |
1583 | * unoptimizing. | |
1584 | */ | |
6f0f1dd7 MH |
1585 | goto disarmed; |
1586 | else { | |
1587 | /* If disabling probe has special handlers, update aggrprobe */ | |
e8386a0c | 1588 | if (p->break_handler && !kprobe_gone(p)) |
6d8e40a8 | 1589 | ap->break_handler = NULL; |
e8386a0c | 1590 | if (p->post_handler && !kprobe_gone(p)) { |
6d8e40a8 | 1591 | list_for_each_entry_rcu(list_p, &ap->list, list) { |
9861668f MH |
1592 | if ((list_p != p) && (list_p->post_handler)) |
1593 | goto noclean; | |
1594 | } | |
6d8e40a8 | 1595 | ap->post_handler = NULL; |
9861668f MH |
1596 | } |
1597 | noclean: | |
6f0f1dd7 MH |
1598 | /* |
1599 | * Remove from the aggrprobe: this path will do nothing in | |
1600 | * __unregister_kprobe_bottom(). | |
1601 | */ | |
49a2a1b8 | 1602 | list_del_rcu(&p->list); |
6f0f1dd7 MH |
1603 | if (!kprobe_disabled(ap) && !kprobes_all_disarmed) |
1604 | /* | |
1605 | * Try to optimize this probe again, because post | |
1606 | * handler may have been changed. | |
1607 | */ | |
1608 | optimize_kprobe(ap); | |
49a2a1b8 | 1609 | } |
9861668f | 1610 | return 0; |
6f0f1dd7 MH |
1611 | |
1612 | disarmed: | |
6274de49 | 1613 | BUG_ON(!kprobe_disarmed(ap)); |
6f0f1dd7 MH |
1614 | hlist_del_rcu(&ap->hlist); |
1615 | return 0; | |
9861668f | 1616 | } |
3516a460 | 1617 | |
9861668f MH |
1618 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
1619 | { | |
6d8e40a8 | 1620 | struct kprobe *ap; |
b3e55c72 | 1621 | |
e8386a0c | 1622 | if (list_empty(&p->list)) |
6274de49 | 1623 | /* This is an independent kprobe */ |
0498b635 | 1624 | arch_remove_kprobe(p); |
e8386a0c | 1625 | else if (list_is_singular(&p->list)) { |
6274de49 | 1626 | /* This is the last child of an aggrprobe */ |
6d8e40a8 | 1627 | ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0c | 1628 | list_del(&p->list); |
6d8e40a8 | 1629 | free_aggr_kprobe(ap); |
9861668f | 1630 | } |
6274de49 | 1631 | /* Otherwise, do nothing. */ |
9861668f MH |
1632 | } |
1633 | ||
49ad2fd7 | 1634 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1635 | { |
1636 | int i, ret = 0; | |
1637 | ||
1638 | if (num <= 0) | |
1639 | return -EINVAL; | |
1640 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1641 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1642 | if (ret < 0) { |
1643 | if (i > 0) | |
1644 | unregister_kprobes(kps, i); | |
9861668f | 1645 | break; |
36721656 | 1646 | } |
49a2a1b8 | 1647 | } |
9861668f MH |
1648 | return ret; |
1649 | } | |
99081ab5 | 1650 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1651 | |
9861668f MH |
1652 | void __kprobes unregister_kprobe(struct kprobe *p) |
1653 | { | |
1654 | unregister_kprobes(&p, 1); | |
1655 | } | |
99081ab5 | 1656 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1657 | |
9861668f MH |
1658 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
1659 | { | |
1660 | int i; | |
1661 | ||
1662 | if (num <= 0) | |
1663 | return; | |
1664 | mutex_lock(&kprobe_mutex); | |
1665 | for (i = 0; i < num; i++) | |
1666 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1667 | kps[i]->addr = NULL; | |
1668 | mutex_unlock(&kprobe_mutex); | |
1669 | ||
1670 | synchronize_sched(); | |
1671 | for (i = 0; i < num; i++) | |
1672 | if (kps[i]->addr) | |
1673 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1674 | } |
99081ab5 | 1675 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 LT |
1676 | |
1677 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
1678 | .notifier_call = kprobe_exceptions_notify, |
1679 | .priority = 0x7fffffff /* we need to be notified first */ | |
1680 | }; | |
1681 | ||
3d7e3382 ME |
1682 | unsigned long __weak arch_deref_entry_point(void *entry) |
1683 | { | |
1684 | return (unsigned long)entry; | |
1685 | } | |
1da177e4 | 1686 | |
49ad2fd7 | 1687 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 1688 | { |
26b31c19 MH |
1689 | struct jprobe *jp; |
1690 | int ret = 0, i; | |
3d7e3382 | 1691 | |
26b31c19 | 1692 | if (num <= 0) |
3d7e3382 | 1693 | return -EINVAL; |
26b31c19 | 1694 | for (i = 0; i < num; i++) { |
05662bdb | 1695 | unsigned long addr, offset; |
26b31c19 MH |
1696 | jp = jps[i]; |
1697 | addr = arch_deref_entry_point(jp->entry); | |
1698 | ||
05662bdb NK |
1699 | /* Verify probepoint is a function entry point */ |
1700 | if (kallsyms_lookup_size_offset(addr, NULL, &offset) && | |
1701 | offset == 0) { | |
1702 | jp->kp.pre_handler = setjmp_pre_handler; | |
1703 | jp->kp.break_handler = longjmp_break_handler; | |
1704 | ret = register_kprobe(&jp->kp); | |
1705 | } else | |
1706 | ret = -EINVAL; | |
edbaadbe | 1707 | |
67dddaad MH |
1708 | if (ret < 0) { |
1709 | if (i > 0) | |
1710 | unregister_jprobes(jps, i); | |
26b31c19 MH |
1711 | break; |
1712 | } | |
1713 | } | |
1714 | return ret; | |
1715 | } | |
99081ab5 | 1716 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 1717 | |
26b31c19 MH |
1718 | int __kprobes register_jprobe(struct jprobe *jp) |
1719 | { | |
49ad2fd7 | 1720 | return register_jprobes(&jp, 1); |
1da177e4 | 1721 | } |
99081ab5 | 1722 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 1723 | |
d0aaff97 | 1724 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 1725 | { |
26b31c19 MH |
1726 | unregister_jprobes(&jp, 1); |
1727 | } | |
99081ab5 | 1728 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 1729 | |
26b31c19 MH |
1730 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
1731 | { | |
1732 | int i; | |
1733 | ||
1734 | if (num <= 0) | |
1735 | return; | |
1736 | mutex_lock(&kprobe_mutex); | |
1737 | for (i = 0; i < num; i++) | |
1738 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
1739 | jps[i]->kp.addr = NULL; | |
1740 | mutex_unlock(&kprobe_mutex); | |
1741 | ||
1742 | synchronize_sched(); | |
1743 | for (i = 0; i < num; i++) { | |
1744 | if (jps[i]->kp.addr) | |
1745 | __unregister_kprobe_bottom(&jps[i]->kp); | |
1746 | } | |
1da177e4 | 1747 | } |
99081ab5 | 1748 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 1749 | |
9edddaa2 | 1750 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1751 | /* |
1752 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1753 | * hits it will set up the return probe. | |
1754 | */ | |
1755 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
1756 | struct pt_regs *regs) | |
1757 | { | |
1758 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1759 | unsigned long hash, flags = 0; |
1760 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
1761 | |
1762 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 | 1763 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
ec484608 | 1764 | raw_spin_lock_irqsave(&rp->lock, flags); |
4c4308cb | 1765 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1766 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1767 | struct kretprobe_instance, hlist); |
1768 | hlist_del(&ri->hlist); | |
ec484608 | 1769 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1770 | |
4c4308cb CH |
1771 | ri->rp = rp; |
1772 | ri->task = current; | |
f47cd9b5 | 1773 | |
55ca6140 JL |
1774 | if (rp->entry_handler && rp->entry_handler(ri, regs)) { |
1775 | raw_spin_lock_irqsave(&rp->lock, flags); | |
1776 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
1777 | raw_spin_unlock_irqrestore(&rp->lock, flags); | |
f47cd9b5 | 1778 | return 0; |
55ca6140 | 1779 | } |
f47cd9b5 | 1780 | |
4c4308cb CH |
1781 | arch_prepare_kretprobe(ri, regs); |
1782 | ||
1783 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1784 | INIT_HLIST_NODE(&ri->hlist); |
1785 | kretprobe_table_lock(hash, &flags); | |
1786 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1787 | kretprobe_table_unlock(hash, &flags); | |
1788 | } else { | |
4c4308cb | 1789 | rp->nmissed++; |
ec484608 | 1790 | raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5 | 1791 | } |
e65cefe8 AB |
1792 | return 0; |
1793 | } | |
1794 | ||
49ad2fd7 | 1795 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1796 | { |
1797 | int ret = 0; | |
1798 | struct kretprobe_instance *inst; | |
1799 | int i; | |
b2a5cd69 | 1800 | void *addr; |
f438d914 MH |
1801 | |
1802 | if (kretprobe_blacklist_size) { | |
b2a5cd69 | 1803 | addr = kprobe_addr(&rp->kp); |
bc81d48d MH |
1804 | if (IS_ERR(addr)) |
1805 | return PTR_ERR(addr); | |
f438d914 MH |
1806 | |
1807 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1808 | if (kretprobe_blacklist[i].addr == addr) | |
1809 | return -EINVAL; | |
1810 | } | |
1811 | } | |
b94cce92 HN |
1812 | |
1813 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1814 | rp->kp.post_handler = NULL; |
1815 | rp->kp.fault_handler = NULL; | |
1816 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1817 | |
1818 | /* Pre-allocate memory for max kretprobe instances */ | |
1819 | if (rp->maxactive <= 0) { | |
1820 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1821 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1822 | #else |
4dae560f | 1823 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1824 | #endif |
1825 | } | |
ec484608 | 1826 | raw_spin_lock_init(&rp->lock); |
b94cce92 HN |
1827 | INIT_HLIST_HEAD(&rp->free_instances); |
1828 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1829 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1830 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1831 | if (inst == NULL) { |
1832 | free_rp_inst(rp); | |
1833 | return -ENOMEM; | |
1834 | } | |
ef53d9c5 S |
1835 | INIT_HLIST_NODE(&inst->hlist); |
1836 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1837 | } |
1838 | ||
1839 | rp->nmissed = 0; | |
1840 | /* Establish function entry probe point */ | |
49ad2fd7 | 1841 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1842 | if (ret != 0) |
b94cce92 HN |
1843 | free_rp_inst(rp); |
1844 | return ret; | |
1845 | } | |
99081ab5 | 1846 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1847 | |
49ad2fd7 | 1848 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1849 | { |
1850 | int ret = 0, i; | |
1851 | ||
1852 | if (num <= 0) | |
1853 | return -EINVAL; | |
1854 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1855 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1856 | if (ret < 0) { |
1857 | if (i > 0) | |
1858 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1859 | break; |
1860 | } | |
1861 | } | |
1862 | return ret; | |
1863 | } | |
99081ab5 | 1864 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1865 | |
4a296e07 MH |
1866 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1867 | { | |
1868 | unregister_kretprobes(&rp, 1); | |
1869 | } | |
99081ab5 | 1870 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1871 | |
4a296e07 MH |
1872 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1873 | { | |
1874 | int i; | |
1875 | ||
1876 | if (num <= 0) | |
1877 | return; | |
1878 | mutex_lock(&kprobe_mutex); | |
1879 | for (i = 0; i < num; i++) | |
1880 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1881 | rps[i]->kp.addr = NULL; | |
1882 | mutex_unlock(&kprobe_mutex); | |
1883 | ||
1884 | synchronize_sched(); | |
1885 | for (i = 0; i < num; i++) { | |
1886 | if (rps[i]->kp.addr) { | |
1887 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1888 | cleanup_rp_inst(rps[i]); | |
1889 | } | |
1890 | } | |
1891 | } | |
99081ab5 | 1892 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 1893 | |
9edddaa2 | 1894 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1895 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1896 | { |
1897 | return -ENOSYS; | |
1898 | } | |
99081ab5 | 1899 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1900 | |
4a296e07 | 1901 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1902 | { |
4a296e07 | 1903 | return -ENOSYS; |
346fd59b | 1904 | } |
99081ab5 MH |
1905 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1906 | ||
d0aaff97 | 1907 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1908 | { |
4a296e07 | 1909 | } |
99081ab5 | 1910 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 1911 | |
4a296e07 MH |
1912 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1913 | { | |
1914 | } | |
99081ab5 | 1915 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 1916 | |
4a296e07 MH |
1917 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1918 | struct pt_regs *regs) | |
1919 | { | |
1920 | return 0; | |
b94cce92 HN |
1921 | } |
1922 | ||
4a296e07 MH |
1923 | #endif /* CONFIG_KRETPROBES */ |
1924 | ||
e8386a0c MH |
1925 | /* Set the kprobe gone and remove its instruction buffer. */ |
1926 | static void __kprobes kill_kprobe(struct kprobe *p) | |
1927 | { | |
1928 | struct kprobe *kp; | |
de5bd88d | 1929 | |
e8386a0c | 1930 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 1931 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
1932 | /* |
1933 | * If this is an aggr_kprobe, we have to list all the | |
1934 | * chained probes and mark them GONE. | |
1935 | */ | |
1936 | list_for_each_entry_rcu(kp, &p->list, list) | |
1937 | kp->flags |= KPROBE_FLAG_GONE; | |
1938 | p->post_handler = NULL; | |
1939 | p->break_handler = NULL; | |
afd66255 | 1940 | kill_optimized_kprobe(p); |
e8386a0c MH |
1941 | } |
1942 | /* | |
1943 | * Here, we can remove insn_slot safely, because no thread calls | |
1944 | * the original probed function (which will be freed soon) any more. | |
1945 | */ | |
1946 | arch_remove_kprobe(p); | |
1947 | } | |
1948 | ||
c0614829 MH |
1949 | /* Disable one kprobe */ |
1950 | int __kprobes disable_kprobe(struct kprobe *kp) | |
1951 | { | |
1952 | int ret = 0; | |
c0614829 MH |
1953 | |
1954 | mutex_lock(&kprobe_mutex); | |
1955 | ||
6f0f1dd7 MH |
1956 | /* Disable this kprobe */ |
1957 | if (__disable_kprobe(kp) == NULL) | |
c0614829 | 1958 | ret = -EINVAL; |
c0614829 | 1959 | |
c0614829 MH |
1960 | mutex_unlock(&kprobe_mutex); |
1961 | return ret; | |
1962 | } | |
1963 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
1964 | ||
1965 | /* Enable one kprobe */ | |
1966 | int __kprobes enable_kprobe(struct kprobe *kp) | |
1967 | { | |
1968 | int ret = 0; | |
1969 | struct kprobe *p; | |
1970 | ||
1971 | mutex_lock(&kprobe_mutex); | |
1972 | ||
1973 | /* Check whether specified probe is valid. */ | |
1974 | p = __get_valid_kprobe(kp); | |
1975 | if (unlikely(p == NULL)) { | |
1976 | ret = -EINVAL; | |
1977 | goto out; | |
1978 | } | |
1979 | ||
1980 | if (kprobe_gone(kp)) { | |
1981 | /* This kprobe has gone, we couldn't enable it. */ | |
1982 | ret = -EINVAL; | |
1983 | goto out; | |
1984 | } | |
1985 | ||
1986 | if (p != kp) | |
1987 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
1988 | ||
1989 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
1990 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1991 | arm_kprobe(p); | |
1992 | } | |
1993 | out: | |
1994 | mutex_unlock(&kprobe_mutex); | |
1995 | return ret; | |
1996 | } | |
1997 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
1998 | ||
24851d24 FW |
1999 | void __kprobes dump_kprobe(struct kprobe *kp) |
2000 | { | |
2001 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
2002 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
2003 | kp->symbol_name, kp->addr, kp->offset); | |
2004 | } | |
2005 | ||
e8386a0c MH |
2006 | /* Module notifier call back, checking kprobes on the module */ |
2007 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, | |
2008 | unsigned long val, void *data) | |
2009 | { | |
2010 | struct module *mod = data; | |
2011 | struct hlist_head *head; | |
e8386a0c MH |
2012 | struct kprobe *p; |
2013 | unsigned int i; | |
f24659d9 | 2014 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 2015 | |
f24659d9 | 2016 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
2017 | return NOTIFY_DONE; |
2018 | ||
2019 | /* | |
f24659d9 MH |
2020 | * When MODULE_STATE_GOING was notified, both of module .text and |
2021 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
2022 | * notified, only .init.text section would be freed. We need to | |
2023 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
2024 | */ |
2025 | mutex_lock(&kprobe_mutex); | |
2026 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
2027 | head = &kprobe_table[i]; | |
b67bfe0d | 2028 | hlist_for_each_entry_rcu(p, head, hlist) |
f24659d9 MH |
2029 | if (within_module_init((unsigned long)p->addr, mod) || |
2030 | (checkcore && | |
2031 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
2032 | /* |
2033 | * The vaddr this probe is installed will soon | |
2034 | * be vfreed buy not synced to disk. Hence, | |
2035 | * disarming the breakpoint isn't needed. | |
2036 | */ | |
2037 | kill_kprobe(p); | |
2038 | } | |
2039 | } | |
2040 | mutex_unlock(&kprobe_mutex); | |
2041 | return NOTIFY_DONE; | |
2042 | } | |
2043 | ||
2044 | static struct notifier_block kprobe_module_nb = { | |
2045 | .notifier_call = kprobes_module_callback, | |
2046 | .priority = 0 | |
2047 | }; | |
2048 | ||
1da177e4 LT |
2049 | static int __init init_kprobes(void) |
2050 | { | |
2051 | int i, err = 0; | |
3d8d996e SD |
2052 | unsigned long offset = 0, size = 0; |
2053 | char *modname, namebuf[128]; | |
2054 | const char *symbol_name; | |
2055 | void *addr; | |
2056 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
2057 | |
2058 | /* FIXME allocate the probe table, currently defined statically */ | |
2059 | /* initialize all list heads */ | |
b94cce92 | 2060 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 2061 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 2062 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ec484608 | 2063 | raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 2064 | } |
1da177e4 | 2065 | |
3d8d996e SD |
2066 | /* |
2067 | * Lookup and populate the kprobe_blacklist. | |
2068 | * | |
2069 | * Unlike the kretprobe blacklist, we'll need to determine | |
2070 | * the range of addresses that belong to the said functions, | |
2071 | * since a kprobe need not necessarily be at the beginning | |
2072 | * of a function. | |
2073 | */ | |
2074 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
2075 | kprobe_lookup_name(kb->name, addr); | |
2076 | if (!addr) | |
2077 | continue; | |
2078 | ||
2079 | kb->start_addr = (unsigned long)addr; | |
2080 | symbol_name = kallsyms_lookup(kb->start_addr, | |
2081 | &size, &offset, &modname, namebuf); | |
2082 | if (!symbol_name) | |
2083 | kb->range = 0; | |
2084 | else | |
2085 | kb->range = size; | |
2086 | } | |
2087 | ||
f438d914 MH |
2088 | if (kretprobe_blacklist_size) { |
2089 | /* lookup the function address from its name */ | |
2090 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
2091 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
2092 | kretprobe_blacklist[i].addr); | |
2093 | if (!kretprobe_blacklist[i].addr) | |
2094 | printk("kretprobe: lookup failed: %s\n", | |
2095 | kretprobe_blacklist[i].name); | |
2096 | } | |
2097 | } | |
2098 | ||
b2be84df MH |
2099 | #if defined(CONFIG_OPTPROBES) |
2100 | #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) | |
afd66255 MH |
2101 | /* Init kprobe_optinsn_slots */ |
2102 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
2103 | #endif | |
b2be84df MH |
2104 | /* By default, kprobes can be optimized */ |
2105 | kprobes_allow_optimization = true; | |
2106 | #endif | |
afd66255 | 2107 | |
e579abeb MH |
2108 | /* By default, kprobes are armed */ |
2109 | kprobes_all_disarmed = false; | |
bf8f6e5b | 2110 | |
6772926b | 2111 | err = arch_init_kprobes(); |
802eae7c RL |
2112 | if (!err) |
2113 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
2114 | if (!err) |
2115 | err = register_module_notifier(&kprobe_module_nb); | |
2116 | ||
ef53d9c5 | 2117 | kprobes_initialized = (err == 0); |
802eae7c | 2118 | |
8c1c9356 AM |
2119 | if (!err) |
2120 | init_test_probes(); | |
1da177e4 LT |
2121 | return err; |
2122 | } | |
2123 | ||
346fd59b SD |
2124 | #ifdef CONFIG_DEBUG_FS |
2125 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
afd66255 | 2126 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
2127 | { |
2128 | char *kprobe_type; | |
2129 | ||
2130 | if (p->pre_handler == pre_handler_kretprobe) | |
2131 | kprobe_type = "r"; | |
2132 | else if (p->pre_handler == setjmp_pre_handler) | |
2133 | kprobe_type = "j"; | |
2134 | else | |
2135 | kprobe_type = "k"; | |
afd66255 | 2136 | |
346fd59b | 2137 | if (sym) |
afd66255 | 2138 | seq_printf(pi, "%p %s %s+0x%x %s ", |
de5bd88d | 2139 | p->addr, kprobe_type, sym, offset, |
afd66255 | 2140 | (modname ? modname : " ")); |
346fd59b | 2141 | else |
afd66255 MH |
2142 | seq_printf(pi, "%p %s %p ", |
2143 | p->addr, kprobe_type, p->addr); | |
2144 | ||
2145 | if (!pp) | |
2146 | pp = p; | |
ae6aa16f | 2147 | seq_printf(pi, "%s%s%s%s\n", |
afd66255 MH |
2148 | (kprobe_gone(p) ? "[GONE]" : ""), |
2149 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
ae6aa16f MH |
2150 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), |
2151 | (kprobe_ftrace(pp) ? "[FTRACE]" : "")); | |
346fd59b SD |
2152 | } |
2153 | ||
2154 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
2155 | { | |
2156 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
2157 | } | |
2158 | ||
2159 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
2160 | { | |
2161 | (*pos)++; | |
2162 | if (*pos >= KPROBE_TABLE_SIZE) | |
2163 | return NULL; | |
2164 | return pos; | |
2165 | } | |
2166 | ||
2167 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
2168 | { | |
2169 | /* Nothing to do */ | |
2170 | } | |
2171 | ||
2172 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
2173 | { | |
2174 | struct hlist_head *head; | |
346fd59b SD |
2175 | struct kprobe *p, *kp; |
2176 | const char *sym = NULL; | |
2177 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 2178 | unsigned long offset = 0; |
346fd59b SD |
2179 | char *modname, namebuf[128]; |
2180 | ||
2181 | head = &kprobe_table[i]; | |
2182 | preempt_disable(); | |
b67bfe0d | 2183 | hlist_for_each_entry_rcu(p, head, hlist) { |
ffb45122 | 2184 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 2185 | &offset, &modname, namebuf); |
afd66255 | 2186 | if (kprobe_aggrprobe(p)) { |
346fd59b | 2187 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 2188 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 2189 | } else |
afd66255 | 2190 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
2191 | } |
2192 | preempt_enable(); | |
2193 | return 0; | |
2194 | } | |
2195 | ||
88e9d34c | 2196 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
2197 | .start = kprobe_seq_start, |
2198 | .next = kprobe_seq_next, | |
2199 | .stop = kprobe_seq_stop, | |
2200 | .show = show_kprobe_addr | |
2201 | }; | |
2202 | ||
2203 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
2204 | { | |
2205 | return seq_open(filp, &kprobes_seq_ops); | |
2206 | } | |
2207 | ||
828c0950 | 2208 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
2209 | .open = kprobes_open, |
2210 | .read = seq_read, | |
2211 | .llseek = seq_lseek, | |
2212 | .release = seq_release, | |
2213 | }; | |
2214 | ||
e579abeb | 2215 | static void __kprobes arm_all_kprobes(void) |
bf8f6e5b AM |
2216 | { |
2217 | struct hlist_head *head; | |
bf8f6e5b AM |
2218 | struct kprobe *p; |
2219 | unsigned int i; | |
2220 | ||
2221 | mutex_lock(&kprobe_mutex); | |
2222 | ||
e579abeb MH |
2223 | /* If kprobes are armed, just return */ |
2224 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
2225 | goto already_enabled; |
2226 | ||
afd66255 | 2227 | /* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b AM |
2228 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2229 | head = &kprobe_table[i]; | |
b67bfe0d | 2230 | hlist_for_each_entry_rcu(p, head, hlist) |
de5bd88d | 2231 | if (!kprobe_disabled(p)) |
ae6aa16f | 2232 | arm_kprobe(p); |
bf8f6e5b AM |
2233 | } |
2234 | ||
e579abeb | 2235 | kprobes_all_disarmed = false; |
bf8f6e5b AM |
2236 | printk(KERN_INFO "Kprobes globally enabled\n"); |
2237 | ||
2238 | already_enabled: | |
2239 | mutex_unlock(&kprobe_mutex); | |
2240 | return; | |
2241 | } | |
2242 | ||
e579abeb | 2243 | static void __kprobes disarm_all_kprobes(void) |
bf8f6e5b AM |
2244 | { |
2245 | struct hlist_head *head; | |
bf8f6e5b AM |
2246 | struct kprobe *p; |
2247 | unsigned int i; | |
2248 | ||
2249 | mutex_lock(&kprobe_mutex); | |
2250 | ||
e579abeb | 2251 | /* If kprobes are already disarmed, just return */ |
6274de49 MH |
2252 | if (kprobes_all_disarmed) { |
2253 | mutex_unlock(&kprobe_mutex); | |
2254 | return; | |
2255 | } | |
bf8f6e5b | 2256 | |
e579abeb | 2257 | kprobes_all_disarmed = true; |
bf8f6e5b | 2258 | printk(KERN_INFO "Kprobes globally disabled\n"); |
afd66255 | 2259 | |
bf8f6e5b AM |
2260 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
2261 | head = &kprobe_table[i]; | |
b67bfe0d | 2262 | hlist_for_each_entry_rcu(p, head, hlist) { |
de5bd88d | 2263 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
ae6aa16f | 2264 | disarm_kprobe(p, false); |
bf8f6e5b AM |
2265 | } |
2266 | } | |
bf8f6e5b | 2267 | mutex_unlock(&kprobe_mutex); |
bf8f6e5b | 2268 | |
6274de49 MH |
2269 | /* Wait for disarming all kprobes by optimizer */ |
2270 | wait_for_kprobe_optimizer(); | |
bf8f6e5b AM |
2271 | } |
2272 | ||
2273 | /* | |
2274 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
2275 | * when the bool state is switched. We can reuse that facility when | |
2276 | * available | |
2277 | */ | |
2278 | static ssize_t read_enabled_file_bool(struct file *file, | |
2279 | char __user *user_buf, size_t count, loff_t *ppos) | |
2280 | { | |
2281 | char buf[3]; | |
2282 | ||
e579abeb | 2283 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
2284 | buf[0] = '1'; |
2285 | else | |
2286 | buf[0] = '0'; | |
2287 | buf[1] = '\n'; | |
2288 | buf[2] = 0x00; | |
2289 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
2290 | } | |
2291 | ||
2292 | static ssize_t write_enabled_file_bool(struct file *file, | |
2293 | const char __user *user_buf, size_t count, loff_t *ppos) | |
2294 | { | |
2295 | char buf[32]; | |
efeb156e | 2296 | size_t buf_size; |
bf8f6e5b AM |
2297 | |
2298 | buf_size = min(count, (sizeof(buf)-1)); | |
2299 | if (copy_from_user(buf, user_buf, buf_size)) | |
2300 | return -EFAULT; | |
2301 | ||
10fb46d5 | 2302 | buf[buf_size] = '\0'; |
bf8f6e5b AM |
2303 | switch (buf[0]) { |
2304 | case 'y': | |
2305 | case 'Y': | |
2306 | case '1': | |
e579abeb | 2307 | arm_all_kprobes(); |
bf8f6e5b AM |
2308 | break; |
2309 | case 'n': | |
2310 | case 'N': | |
2311 | case '0': | |
e579abeb | 2312 | disarm_all_kprobes(); |
bf8f6e5b | 2313 | break; |
10fb46d5 MK |
2314 | default: |
2315 | return -EINVAL; | |
bf8f6e5b AM |
2316 | } |
2317 | ||
2318 | return count; | |
2319 | } | |
2320 | ||
828c0950 | 2321 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
2322 | .read = read_enabled_file_bool, |
2323 | .write = write_enabled_file_bool, | |
6038f373 | 2324 | .llseek = default_llseek, |
bf8f6e5b AM |
2325 | }; |
2326 | ||
346fd59b SD |
2327 | static int __kprobes debugfs_kprobe_init(void) |
2328 | { | |
2329 | struct dentry *dir, *file; | |
bf8f6e5b | 2330 | unsigned int value = 1; |
346fd59b SD |
2331 | |
2332 | dir = debugfs_create_dir("kprobes", NULL); | |
2333 | if (!dir) | |
2334 | return -ENOMEM; | |
2335 | ||
e3869792 | 2336 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
2337 | &debugfs_kprobes_operations); |
2338 | if (!file) { | |
2339 | debugfs_remove(dir); | |
2340 | return -ENOMEM; | |
2341 | } | |
2342 | ||
bf8f6e5b AM |
2343 | file = debugfs_create_file("enabled", 0600, dir, |
2344 | &value, &fops_kp); | |
2345 | if (!file) { | |
2346 | debugfs_remove(dir); | |
2347 | return -ENOMEM; | |
2348 | } | |
2349 | ||
346fd59b SD |
2350 | return 0; |
2351 | } | |
2352 | ||
2353 | late_initcall(debugfs_kprobe_init); | |
2354 | #endif /* CONFIG_DEBUG_FS */ | |
2355 | ||
2356 | module_init(init_kprobes); | |
1da177e4 | 2357 | |
99081ab5 | 2358 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 2359 | EXPORT_SYMBOL_GPL(jprobe_return); |