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> |
1da177e4 | 39 | #include <linux/module.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> | |
1eeb66a1 | 45 | #include <linux/kdebug.h> |
4460fdad | 46 | #include <linux/memory.h> |
4554dbcb | 47 | #include <linux/ftrace.h> |
afd66255 | 48 | #include <linux/cpu.h> |
bf8f6e5b | 49 | |
d0aaff97 | 50 | #include <asm-generic/sections.h> |
1da177e4 LT |
51 | #include <asm/cacheflush.h> |
52 | #include <asm/errno.h> | |
bf8f6e5b | 53 | #include <asm/uaccess.h> |
1da177e4 LT |
54 | |
55 | #define KPROBE_HASH_BITS 6 | |
56 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
57 | ||
3a872d89 AM |
58 | |
59 | /* | |
60 | * Some oddball architectures like 64bit powerpc have function descriptors | |
61 | * so this must be overridable. | |
62 | */ | |
63 | #ifndef kprobe_lookup_name | |
64 | #define kprobe_lookup_name(name, addr) \ | |
65 | addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name))) | |
66 | #endif | |
67 | ||
ef53d9c5 | 68 | static int kprobes_initialized; |
1da177e4 | 69 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
b94cce92 | 70 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 | 71 | |
bf8f6e5b | 72 | /* NOTE: change this value only with kprobe_mutex held */ |
e579abeb | 73 | static bool kprobes_all_disarmed; |
bf8f6e5b | 74 | |
12941560 | 75 | static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ |
e6584523 | 76 | static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
ef53d9c5 | 77 | static struct { |
7e036d04 | 78 | spinlock_t lock ____cacheline_aligned_in_smp; |
ef53d9c5 S |
79 | } kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
80 | ||
81 | static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) | |
82 | { | |
83 | return &(kretprobe_table_locks[hash].lock); | |
84 | } | |
1da177e4 | 85 | |
3d8d996e SD |
86 | /* |
87 | * Normally, functions that we'd want to prohibit kprobes in, are marked | |
88 | * __kprobes. But, there are cases where such functions already belong to | |
89 | * a different section (__sched for preempt_schedule) | |
90 | * | |
91 | * For such cases, we now have a blacklist | |
92 | */ | |
544304b2 | 93 | static struct kprobe_blackpoint kprobe_blacklist[] = { |
3d8d996e | 94 | {"preempt_schedule",}, |
65e234ec | 95 | {"native_get_debugreg",}, |
a00e817f MH |
96 | {"irq_entries_start",}, |
97 | {"common_interrupt",}, | |
5ecaafdb | 98 | {"mcount",}, /* mcount can be called from everywhere */ |
3d8d996e SD |
99 | {NULL} /* Terminator */ |
100 | }; | |
101 | ||
2d14e39d | 102 | #ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
9ec4b1f3 AM |
103 | /* |
104 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
105 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
106 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
107 | * is a recipe for disaster | |
108 | */ | |
9ec4b1f3 | 109 | struct kprobe_insn_page { |
c5cb5a2d | 110 | struct list_head list; |
9ec4b1f3 | 111 | kprobe_opcode_t *insns; /* Page of instruction slots */ |
9ec4b1f3 | 112 | int nused; |
b4c6c34a | 113 | int ngarbage; |
4610ee1d | 114 | char slot_used[]; |
9ec4b1f3 AM |
115 | }; |
116 | ||
4610ee1d MH |
117 | #define KPROBE_INSN_PAGE_SIZE(slots) \ |
118 | (offsetof(struct kprobe_insn_page, slot_used) + \ | |
119 | (sizeof(char) * (slots))) | |
120 | ||
121 | struct kprobe_insn_cache { | |
122 | struct list_head pages; /* list of kprobe_insn_page */ | |
123 | size_t insn_size; /* size of instruction slot */ | |
124 | int nr_garbage; | |
125 | }; | |
126 | ||
127 | static int slots_per_page(struct kprobe_insn_cache *c) | |
128 | { | |
129 | return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); | |
130 | } | |
131 | ||
ab40c5c6 MH |
132 | enum kprobe_slot_state { |
133 | SLOT_CLEAN = 0, | |
134 | SLOT_DIRTY = 1, | |
135 | SLOT_USED = 2, | |
136 | }; | |
137 | ||
4610ee1d MH |
138 | static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */ |
139 | static struct kprobe_insn_cache kprobe_insn_slots = { | |
140 | .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), | |
141 | .insn_size = MAX_INSN_SIZE, | |
142 | .nr_garbage = 0, | |
143 | }; | |
144 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c); | |
b4c6c34a | 145 | |
9ec4b1f3 | 146 | /** |
12941560 | 147 | * __get_insn_slot() - Find a slot on an executable page for an instruction. |
9ec4b1f3 AM |
148 | * We allocate an executable page if there's no room on existing ones. |
149 | */ | |
4610ee1d | 150 | static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c) |
9ec4b1f3 AM |
151 | { |
152 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 153 | |
6f716acd | 154 | retry: |
4610ee1d MH |
155 | list_for_each_entry(kip, &c->pages, list) { |
156 | if (kip->nused < slots_per_page(c)) { | |
9ec4b1f3 | 157 | int i; |
4610ee1d | 158 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 MH |
159 | if (kip->slot_used[i] == SLOT_CLEAN) { |
160 | kip->slot_used[i] = SLOT_USED; | |
9ec4b1f3 | 161 | kip->nused++; |
4610ee1d | 162 | return kip->insns + (i * c->insn_size); |
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) |
9ec4b1f3 | 178 | return NULL; |
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); | |
188 | return NULL; | |
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); |
9ec4b1f3 AM |
196 | return kip->insns; |
197 | } | |
198 | ||
4610ee1d | 199 | |
12941560 MH |
200 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
201 | { | |
4610ee1d MH |
202 | kprobe_opcode_t *ret = NULL; |
203 | ||
12941560 | 204 | mutex_lock(&kprobe_insn_mutex); |
4610ee1d | 205 | ret = __get_insn_slot(&kprobe_insn_slots); |
12941560 | 206 | mutex_unlock(&kprobe_insn_mutex); |
4610ee1d | 207 | |
12941560 MH |
208 | return ret; |
209 | } | |
210 | ||
b4c6c34a MH |
211 | /* Return 1 if all garbages are collected, otherwise 0. */ |
212 | static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) | |
213 | { | |
ab40c5c6 | 214 | kip->slot_used[idx] = SLOT_CLEAN; |
b4c6c34a MH |
215 | kip->nused--; |
216 | if (kip->nused == 0) { | |
217 | /* | |
218 | * Page is no longer in use. Free it unless | |
219 | * it's the last one. We keep the last one | |
220 | * so as not to have to set it up again the | |
221 | * next time somebody inserts a probe. | |
222 | */ | |
4610ee1d | 223 | if (!list_is_singular(&kip->list)) { |
c5cb5a2d | 224 | list_del(&kip->list); |
b4c6c34a MH |
225 | module_free(NULL, kip->insns); |
226 | kfree(kip); | |
227 | } | |
228 | return 1; | |
229 | } | |
230 | return 0; | |
231 | } | |
232 | ||
4610ee1d | 233 | static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c) |
b4c6c34a | 234 | { |
c5cb5a2d | 235 | struct kprobe_insn_page *kip, *next; |
b4c6c34a | 236 | |
615d0ebb MH |
237 | /* Ensure no-one is interrupted on the garbages */ |
238 | synchronize_sched(); | |
b4c6c34a | 239 | |
4610ee1d | 240 | list_for_each_entry_safe(kip, next, &c->pages, list) { |
b4c6c34a | 241 | int i; |
b4c6c34a MH |
242 | if (kip->ngarbage == 0) |
243 | continue; | |
244 | kip->ngarbage = 0; /* we will collect all garbages */ | |
4610ee1d | 245 | for (i = 0; i < slots_per_page(c); i++) { |
ab40c5c6 | 246 | if (kip->slot_used[i] == SLOT_DIRTY && |
b4c6c34a MH |
247 | collect_one_slot(kip, i)) |
248 | break; | |
249 | } | |
250 | } | |
4610ee1d | 251 | c->nr_garbage = 0; |
b4c6c34a MH |
252 | return 0; |
253 | } | |
254 | ||
4610ee1d MH |
255 | static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c, |
256 | kprobe_opcode_t *slot, int dirty) | |
9ec4b1f3 AM |
257 | { |
258 | struct kprobe_insn_page *kip; | |
9ec4b1f3 | 259 | |
4610ee1d MH |
260 | list_for_each_entry(kip, &c->pages, list) { |
261 | long idx = ((long)slot - (long)kip->insns) / c->insn_size; | |
262 | if (idx >= 0 && idx < slots_per_page(c)) { | |
263 | WARN_ON(kip->slot_used[idx] != SLOT_USED); | |
b4c6c34a | 264 | if (dirty) { |
4610ee1d | 265 | kip->slot_used[idx] = SLOT_DIRTY; |
b4c6c34a | 266 | kip->ngarbage++; |
4610ee1d MH |
267 | if (++c->nr_garbage > slots_per_page(c)) |
268 | collect_garbage_slots(c); | |
c5cb5a2d | 269 | } else |
4610ee1d MH |
270 | collect_one_slot(kip, idx); |
271 | return; | |
9ec4b1f3 AM |
272 | } |
273 | } | |
4610ee1d MH |
274 | /* Could not free this slot. */ |
275 | WARN_ON(1); | |
276 | } | |
6f716acd | 277 | |
4610ee1d MH |
278 | void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty) |
279 | { | |
280 | mutex_lock(&kprobe_insn_mutex); | |
281 | __free_insn_slot(&kprobe_insn_slots, slot, dirty); | |
12941560 | 282 | mutex_unlock(&kprobe_insn_mutex); |
9ec4b1f3 | 283 | } |
afd66255 MH |
284 | #ifdef CONFIG_OPTPROBES |
285 | /* For optimized_kprobe buffer */ | |
286 | static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */ | |
287 | static struct kprobe_insn_cache kprobe_optinsn_slots = { | |
288 | .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), | |
289 | /* .insn_size is initialized later */ | |
290 | .nr_garbage = 0, | |
291 | }; | |
292 | /* Get a slot for optimized_kprobe buffer */ | |
293 | kprobe_opcode_t __kprobes *get_optinsn_slot(void) | |
294 | { | |
295 | kprobe_opcode_t *ret = NULL; | |
296 | ||
297 | mutex_lock(&kprobe_optinsn_mutex); | |
298 | ret = __get_insn_slot(&kprobe_optinsn_slots); | |
299 | mutex_unlock(&kprobe_optinsn_mutex); | |
300 | ||
301 | return ret; | |
302 | } | |
303 | ||
304 | void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty) | |
305 | { | |
306 | mutex_lock(&kprobe_optinsn_mutex); | |
307 | __free_insn_slot(&kprobe_optinsn_slots, slot, dirty); | |
308 | mutex_unlock(&kprobe_optinsn_mutex); | |
309 | } | |
310 | #endif | |
2d14e39d | 311 | #endif |
9ec4b1f3 | 312 | |
e6584523 AM |
313 | /* We have preemption disabled.. so it is safe to use __ versions */ |
314 | static inline void set_kprobe_instance(struct kprobe *kp) | |
315 | { | |
316 | __get_cpu_var(kprobe_instance) = kp; | |
317 | } | |
318 | ||
319 | static inline void reset_kprobe_instance(void) | |
320 | { | |
321 | __get_cpu_var(kprobe_instance) = NULL; | |
322 | } | |
323 | ||
3516a460 AM |
324 | /* |
325 | * This routine is called either: | |
49a2a1b8 | 326 | * - under the kprobe_mutex - during kprobe_[un]register() |
3516a460 | 327 | * OR |
d217d545 | 328 | * - with preemption disabled - from arch/xxx/kernel/kprobes.c |
3516a460 | 329 | */ |
d0aaff97 | 330 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
331 | { |
332 | struct hlist_head *head; | |
333 | struct hlist_node *node; | |
3516a460 | 334 | struct kprobe *p; |
1da177e4 LT |
335 | |
336 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
3516a460 | 337 | hlist_for_each_entry_rcu(p, node, head, hlist) { |
1da177e4 LT |
338 | if (p->addr == addr) |
339 | return p; | |
340 | } | |
afd66255 | 341 | |
1da177e4 LT |
342 | return NULL; |
343 | } | |
344 | ||
afd66255 MH |
345 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
346 | ||
347 | /* Return true if the kprobe is an aggregator */ | |
348 | static inline int kprobe_aggrprobe(struct kprobe *p) | |
349 | { | |
350 | return p->pre_handler == aggr_pre_handler; | |
351 | } | |
352 | ||
353 | /* | |
354 | * Keep all fields in the kprobe consistent | |
355 | */ | |
356 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
357 | { | |
358 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
359 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
360 | } | |
361 | ||
362 | #ifdef CONFIG_OPTPROBES | |
363 | /* | |
364 | * Call all pre_handler on the list, but ignores its return value. | |
365 | * This must be called from arch-dep optimized caller. | |
366 | */ | |
367 | void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs) | |
368 | { | |
369 | struct kprobe *kp; | |
370 | ||
371 | list_for_each_entry_rcu(kp, &p->list, list) { | |
372 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { | |
373 | set_kprobe_instance(kp); | |
374 | kp->pre_handler(kp, regs); | |
375 | } | |
376 | reset_kprobe_instance(); | |
377 | } | |
378 | } | |
379 | ||
380 | /* Return true(!0) if the kprobe is ready for optimization. */ | |
381 | static inline int kprobe_optready(struct kprobe *p) | |
382 | { | |
383 | struct optimized_kprobe *op; | |
384 | ||
385 | if (kprobe_aggrprobe(p)) { | |
386 | op = container_of(p, struct optimized_kprobe, kp); | |
387 | return arch_prepared_optinsn(&op->optinsn); | |
388 | } | |
389 | ||
390 | return 0; | |
391 | } | |
392 | ||
393 | /* | |
394 | * Return an optimized kprobe whose optimizing code replaces | |
395 | * instructions including addr (exclude breakpoint). | |
396 | */ | |
397 | struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr) | |
398 | { | |
399 | int i; | |
400 | struct kprobe *p = NULL; | |
401 | struct optimized_kprobe *op; | |
402 | ||
403 | /* Don't check i == 0, since that is a breakpoint case. */ | |
404 | for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) | |
405 | p = get_kprobe((void *)(addr - i)); | |
406 | ||
407 | if (p && kprobe_optready(p)) { | |
408 | op = container_of(p, struct optimized_kprobe, kp); | |
409 | if (arch_within_optimized_kprobe(op, addr)) | |
410 | return p; | |
411 | } | |
412 | ||
413 | return NULL; | |
414 | } | |
415 | ||
416 | /* Optimization staging list, protected by kprobe_mutex */ | |
417 | static LIST_HEAD(optimizing_list); | |
418 | ||
419 | static void kprobe_optimizer(struct work_struct *work); | |
420 | static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); | |
421 | #define OPTIMIZE_DELAY 5 | |
422 | ||
423 | /* Kprobe jump optimizer */ | |
424 | static __kprobes void kprobe_optimizer(struct work_struct *work) | |
425 | { | |
426 | struct optimized_kprobe *op, *tmp; | |
427 | ||
428 | /* Lock modules while optimizing kprobes */ | |
429 | mutex_lock(&module_mutex); | |
430 | mutex_lock(&kprobe_mutex); | |
431 | if (kprobes_all_disarmed) | |
432 | goto end; | |
433 | ||
434 | /* | |
435 | * Wait for quiesence period to ensure all running interrupts | |
436 | * are done. Because optprobe may modify multiple instructions | |
437 | * there is a chance that Nth instruction is interrupted. In that | |
438 | * case, running interrupt can return to 2nd-Nth byte of jump | |
439 | * instruction. This wait is for avoiding it. | |
440 | */ | |
441 | synchronize_sched(); | |
442 | ||
443 | /* | |
444 | * The optimization/unoptimization refers online_cpus via | |
445 | * stop_machine() and cpu-hotplug modifies online_cpus. | |
446 | * And same time, text_mutex will be held in cpu-hotplug and here. | |
447 | * This combination can cause a deadlock (cpu-hotplug try to lock | |
448 | * text_mutex but stop_machine can not be done because online_cpus | |
449 | * has been changed) | |
450 | * To avoid this deadlock, we need to call get_online_cpus() | |
451 | * for preventing cpu-hotplug outside of text_mutex locking. | |
452 | */ | |
453 | get_online_cpus(); | |
454 | mutex_lock(&text_mutex); | |
455 | list_for_each_entry_safe(op, tmp, &optimizing_list, list) { | |
456 | WARN_ON(kprobe_disabled(&op->kp)); | |
457 | if (arch_optimize_kprobe(op) < 0) | |
458 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
459 | list_del_init(&op->list); | |
460 | } | |
461 | mutex_unlock(&text_mutex); | |
462 | put_online_cpus(); | |
463 | end: | |
464 | mutex_unlock(&kprobe_mutex); | |
465 | mutex_unlock(&module_mutex); | |
466 | } | |
467 | ||
468 | /* Optimize kprobe if p is ready to be optimized */ | |
469 | static __kprobes void optimize_kprobe(struct kprobe *p) | |
470 | { | |
471 | struct optimized_kprobe *op; | |
472 | ||
473 | /* Check if the kprobe is disabled or not ready for optimization. */ | |
474 | if (!kprobe_optready(p) || | |
475 | (kprobe_disabled(p) || kprobes_all_disarmed)) | |
476 | return; | |
477 | ||
478 | /* Both of break_handler and post_handler are not supported. */ | |
479 | if (p->break_handler || p->post_handler) | |
480 | return; | |
481 | ||
482 | op = container_of(p, struct optimized_kprobe, kp); | |
483 | ||
484 | /* Check there is no other kprobes at the optimized instructions */ | |
485 | if (arch_check_optimized_kprobe(op) < 0) | |
486 | return; | |
487 | ||
488 | /* Check if it is already optimized. */ | |
489 | if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) | |
490 | return; | |
491 | ||
492 | op->kp.flags |= KPROBE_FLAG_OPTIMIZED; | |
493 | list_add(&op->list, &optimizing_list); | |
494 | if (!delayed_work_pending(&optimizing_work)) | |
495 | schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); | |
496 | } | |
497 | ||
498 | /* Unoptimize a kprobe if p is optimized */ | |
499 | static __kprobes void unoptimize_kprobe(struct kprobe *p) | |
500 | { | |
501 | struct optimized_kprobe *op; | |
502 | ||
503 | if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) { | |
504 | op = container_of(p, struct optimized_kprobe, kp); | |
505 | if (!list_empty(&op->list)) | |
506 | /* Dequeue from the optimization queue */ | |
507 | list_del_init(&op->list); | |
508 | else | |
509 | /* Replace jump with break */ | |
510 | arch_unoptimize_kprobe(op); | |
511 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
512 | } | |
513 | } | |
514 | ||
515 | /* Remove optimized instructions */ | |
516 | static void __kprobes kill_optimized_kprobe(struct kprobe *p) | |
517 | { | |
518 | struct optimized_kprobe *op; | |
519 | ||
520 | op = container_of(p, struct optimized_kprobe, kp); | |
521 | if (!list_empty(&op->list)) { | |
522 | /* Dequeue from the optimization queue */ | |
523 | list_del_init(&op->list); | |
524 | op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; | |
525 | } | |
526 | /* Don't unoptimize, because the target code will be freed. */ | |
527 | arch_remove_optimized_kprobe(op); | |
528 | } | |
529 | ||
530 | /* Try to prepare optimized instructions */ | |
531 | static __kprobes void prepare_optimized_kprobe(struct kprobe *p) | |
532 | { | |
533 | struct optimized_kprobe *op; | |
534 | ||
535 | op = container_of(p, struct optimized_kprobe, kp); | |
536 | arch_prepare_optimized_kprobe(op); | |
537 | } | |
538 | ||
539 | /* Free optimized instructions and optimized_kprobe */ | |
540 | static __kprobes void free_aggr_kprobe(struct kprobe *p) | |
541 | { | |
542 | struct optimized_kprobe *op; | |
543 | ||
544 | op = container_of(p, struct optimized_kprobe, kp); | |
545 | arch_remove_optimized_kprobe(op); | |
546 | kfree(op); | |
547 | } | |
548 | ||
549 | /* Allocate new optimized_kprobe and try to prepare optimized instructions */ | |
550 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
551 | { | |
552 | struct optimized_kprobe *op; | |
553 | ||
554 | op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); | |
555 | if (!op) | |
556 | return NULL; | |
557 | ||
558 | INIT_LIST_HEAD(&op->list); | |
559 | op->kp.addr = p->addr; | |
560 | arch_prepare_optimized_kprobe(op); | |
561 | ||
562 | return &op->kp; | |
563 | } | |
564 | ||
565 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); | |
566 | ||
567 | /* | |
568 | * Prepare an optimized_kprobe and optimize it | |
569 | * NOTE: p must be a normal registered kprobe | |
570 | */ | |
571 | static __kprobes void try_to_optimize_kprobe(struct kprobe *p) | |
572 | { | |
573 | struct kprobe *ap; | |
574 | struct optimized_kprobe *op; | |
575 | ||
576 | ap = alloc_aggr_kprobe(p); | |
577 | if (!ap) | |
578 | return; | |
579 | ||
580 | op = container_of(ap, struct optimized_kprobe, kp); | |
581 | if (!arch_prepared_optinsn(&op->optinsn)) { | |
582 | /* If failed to setup optimizing, fallback to kprobe */ | |
583 | free_aggr_kprobe(ap); | |
584 | return; | |
585 | } | |
586 | ||
587 | init_aggr_kprobe(ap, p); | |
588 | optimize_kprobe(ap); | |
589 | } | |
590 | ||
591 | static void __kprobes __arm_kprobe(struct kprobe *p) | |
592 | { | |
593 | struct kprobe *old_p; | |
594 | ||
595 | /* Check collision with other optimized kprobes */ | |
596 | old_p = get_optimized_kprobe((unsigned long)p->addr); | |
597 | if (unlikely(old_p)) | |
598 | unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */ | |
599 | ||
600 | arch_arm_kprobe(p); | |
601 | optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ | |
602 | } | |
603 | ||
604 | static void __kprobes __disarm_kprobe(struct kprobe *p) | |
605 | { | |
606 | struct kprobe *old_p; | |
607 | ||
608 | unoptimize_kprobe(p); /* Try to unoptimize */ | |
609 | arch_disarm_kprobe(p); | |
610 | ||
611 | /* If another kprobe was blocked, optimize it. */ | |
612 | old_p = get_optimized_kprobe((unsigned long)p->addr); | |
613 | if (unlikely(old_p)) | |
614 | optimize_kprobe(old_p); | |
615 | } | |
616 | ||
617 | #else /* !CONFIG_OPTPROBES */ | |
618 | ||
619 | #define optimize_kprobe(p) do {} while (0) | |
620 | #define unoptimize_kprobe(p) do {} while (0) | |
621 | #define kill_optimized_kprobe(p) do {} while (0) | |
622 | #define prepare_optimized_kprobe(p) do {} while (0) | |
623 | #define try_to_optimize_kprobe(p) do {} while (0) | |
624 | #define __arm_kprobe(p) arch_arm_kprobe(p) | |
625 | #define __disarm_kprobe(p) arch_disarm_kprobe(p) | |
626 | ||
627 | static __kprobes void free_aggr_kprobe(struct kprobe *p) | |
628 | { | |
629 | kfree(p); | |
630 | } | |
631 | ||
632 | static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) | |
633 | { | |
634 | return kzalloc(sizeof(struct kprobe), GFP_KERNEL); | |
635 | } | |
636 | #endif /* CONFIG_OPTPROBES */ | |
637 | ||
201517a7 MH |
638 | /* Arm a kprobe with text_mutex */ |
639 | static void __kprobes arm_kprobe(struct kprobe *kp) | |
640 | { | |
afd66255 MH |
641 | /* |
642 | * Here, since __arm_kprobe() doesn't use stop_machine(), | |
643 | * this doesn't cause deadlock on text_mutex. So, we don't | |
644 | * need get_online_cpus(). | |
645 | */ | |
201517a7 | 646 | mutex_lock(&text_mutex); |
afd66255 | 647 | __arm_kprobe(kp); |
201517a7 MH |
648 | mutex_unlock(&text_mutex); |
649 | } | |
650 | ||
651 | /* Disarm a kprobe with text_mutex */ | |
652 | static void __kprobes disarm_kprobe(struct kprobe *kp) | |
653 | { | |
afd66255 | 654 | get_online_cpus(); /* For avoiding text_mutex deadlock */ |
201517a7 | 655 | mutex_lock(&text_mutex); |
afd66255 | 656 | __disarm_kprobe(kp); |
201517a7 | 657 | mutex_unlock(&text_mutex); |
afd66255 | 658 | put_online_cpus(); |
201517a7 MH |
659 | } |
660 | ||
64f562c6 AM |
661 | /* |
662 | * Aggregate handlers for multiple kprobes support - these handlers | |
663 | * take care of invoking the individual kprobe handlers on p->list | |
664 | */ | |
d0aaff97 | 665 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
666 | { |
667 | struct kprobe *kp; | |
668 | ||
3516a460 | 669 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 670 | if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 671 | set_kprobe_instance(kp); |
8b0914ea PP |
672 | if (kp->pre_handler(kp, regs)) |
673 | return 1; | |
64f562c6 | 674 | } |
e6584523 | 675 | reset_kprobe_instance(); |
64f562c6 AM |
676 | } |
677 | return 0; | |
678 | } | |
679 | ||
d0aaff97 PP |
680 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
681 | unsigned long flags) | |
64f562c6 AM |
682 | { |
683 | struct kprobe *kp; | |
684 | ||
3516a460 | 685 | list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d | 686 | if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e6584523 | 687 | set_kprobe_instance(kp); |
64f562c6 | 688 | kp->post_handler(kp, regs, flags); |
e6584523 | 689 | reset_kprobe_instance(); |
64f562c6 AM |
690 | } |
691 | } | |
64f562c6 AM |
692 | } |
693 | ||
d0aaff97 PP |
694 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
695 | int trapnr) | |
64f562c6 | 696 | { |
e6584523 AM |
697 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
698 | ||
64f562c6 AM |
699 | /* |
700 | * if we faulted "during" the execution of a user specified | |
701 | * probe handler, invoke just that probe's fault handler | |
702 | */ | |
e6584523 AM |
703 | if (cur && cur->fault_handler) { |
704 | if (cur->fault_handler(cur, regs, trapnr)) | |
64f562c6 AM |
705 | return 1; |
706 | } | |
707 | return 0; | |
708 | } | |
709 | ||
d0aaff97 | 710 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea | 711 | { |
e6584523 AM |
712 | struct kprobe *cur = __get_cpu_var(kprobe_instance); |
713 | int ret = 0; | |
714 | ||
715 | if (cur && cur->break_handler) { | |
716 | if (cur->break_handler(cur, regs)) | |
717 | ret = 1; | |
8b0914ea | 718 | } |
e6584523 AM |
719 | reset_kprobe_instance(); |
720 | return ret; | |
8b0914ea PP |
721 | } |
722 | ||
bf8d5c52 KA |
723 | /* Walks the list and increments nmissed count for multiprobe case */ |
724 | void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) | |
725 | { | |
726 | struct kprobe *kp; | |
afd66255 | 727 | if (!kprobe_aggrprobe(p)) { |
bf8d5c52 KA |
728 | p->nmissed++; |
729 | } else { | |
730 | list_for_each_entry_rcu(kp, &p->list, list) | |
731 | kp->nmissed++; | |
732 | } | |
733 | return; | |
734 | } | |
735 | ||
99219a3f | 736 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, |
737 | struct hlist_head *head) | |
b94cce92 | 738 | { |
ef53d9c5 S |
739 | struct kretprobe *rp = ri->rp; |
740 | ||
b94cce92 HN |
741 | /* remove rp inst off the rprobe_inst_table */ |
742 | hlist_del(&ri->hlist); | |
ef53d9c5 S |
743 | INIT_HLIST_NODE(&ri->hlist); |
744 | if (likely(rp)) { | |
745 | spin_lock(&rp->lock); | |
746 | hlist_add_head(&ri->hlist, &rp->free_instances); | |
747 | spin_unlock(&rp->lock); | |
b94cce92 HN |
748 | } else |
749 | /* Unregistering */ | |
99219a3f | 750 | hlist_add_head(&ri->hlist, head); |
b94cce92 HN |
751 | } |
752 | ||
017c39bd | 753 | void __kprobes kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5 S |
754 | struct hlist_head **head, unsigned long *flags) |
755 | { | |
756 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
757 | spinlock_t *hlist_lock; | |
758 | ||
759 | *head = &kretprobe_inst_table[hash]; | |
760 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
761 | spin_lock_irqsave(hlist_lock, *flags); | |
762 | } | |
763 | ||
017c39bd MH |
764 | static void __kprobes kretprobe_table_lock(unsigned long hash, |
765 | unsigned long *flags) | |
b94cce92 | 766 | { |
ef53d9c5 S |
767 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); |
768 | spin_lock_irqsave(hlist_lock, *flags); | |
769 | } | |
770 | ||
017c39bd MH |
771 | void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, |
772 | unsigned long *flags) | |
ef53d9c5 S |
773 | { |
774 | unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); | |
775 | spinlock_t *hlist_lock; | |
776 | ||
777 | hlist_lock = kretprobe_table_lock_ptr(hash); | |
778 | spin_unlock_irqrestore(hlist_lock, *flags); | |
779 | } | |
780 | ||
017c39bd | 781 | void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags) |
ef53d9c5 S |
782 | { |
783 | spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); | |
784 | spin_unlock_irqrestore(hlist_lock, *flags); | |
b94cce92 HN |
785 | } |
786 | ||
b94cce92 | 787 | /* |
c6fd91f0 | 788 | * This function is called from finish_task_switch when task tk becomes dead, |
789 | * so that we can recycle any function-return probe instances associated | |
790 | * with this task. These left over instances represent probed functions | |
791 | * that have been called but will never return. | |
b94cce92 | 792 | */ |
d0aaff97 | 793 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 794 | { |
62c27be0 | 795 | struct kretprobe_instance *ri; |
99219a3f | 796 | struct hlist_head *head, empty_rp; |
802eae7c | 797 | struct hlist_node *node, *tmp; |
ef53d9c5 | 798 | unsigned long hash, flags = 0; |
802eae7c | 799 | |
ef53d9c5 S |
800 | if (unlikely(!kprobes_initialized)) |
801 | /* Early boot. kretprobe_table_locks not yet initialized. */ | |
802 | return; | |
803 | ||
804 | hash = hash_ptr(tk, KPROBE_HASH_BITS); | |
805 | head = &kretprobe_inst_table[hash]; | |
806 | kretprobe_table_lock(hash, &flags); | |
62c27be0 | 807 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
808 | if (ri->task == tk) | |
99219a3f | 809 | recycle_rp_inst(ri, &empty_rp); |
62c27be0 | 810 | } |
ef53d9c5 S |
811 | kretprobe_table_unlock(hash, &flags); |
812 | INIT_HLIST_HEAD(&empty_rp); | |
99219a3f | 813 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
814 | hlist_del(&ri->hlist); | |
815 | kfree(ri); | |
816 | } | |
b94cce92 HN |
817 | } |
818 | ||
b94cce92 HN |
819 | static inline void free_rp_inst(struct kretprobe *rp) |
820 | { | |
821 | struct kretprobe_instance *ri; | |
4c4308cb CH |
822 | struct hlist_node *pos, *next; |
823 | ||
ef53d9c5 S |
824 | hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) { |
825 | hlist_del(&ri->hlist); | |
b94cce92 HN |
826 | kfree(ri); |
827 | } | |
828 | } | |
829 | ||
4a296e07 MH |
830 | static void __kprobes cleanup_rp_inst(struct kretprobe *rp) |
831 | { | |
ef53d9c5 | 832 | unsigned long flags, hash; |
4a296e07 MH |
833 | struct kretprobe_instance *ri; |
834 | struct hlist_node *pos, *next; | |
ef53d9c5 S |
835 | struct hlist_head *head; |
836 | ||
4a296e07 | 837 | /* No race here */ |
ef53d9c5 S |
838 | for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { |
839 | kretprobe_table_lock(hash, &flags); | |
840 | head = &kretprobe_inst_table[hash]; | |
841 | hlist_for_each_entry_safe(ri, pos, next, head, hlist) { | |
842 | if (ri->rp == rp) | |
843 | ri->rp = NULL; | |
844 | } | |
845 | kretprobe_table_unlock(hash, &flags); | |
4a296e07 | 846 | } |
4a296e07 MH |
847 | free_rp_inst(rp); |
848 | } | |
849 | ||
8b0914ea | 850 | /* |
b918e5e6 | 851 | * Add the new probe to ap->list. Fail if this is the |
8b0914ea PP |
852 | * second jprobe at the address - two jprobes can't coexist |
853 | */ | |
b918e5e6 | 854 | static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea | 855 | { |
de5bd88d | 856 | BUG_ON(kprobe_gone(ap) || kprobe_gone(p)); |
afd66255 MH |
857 | |
858 | if (p->break_handler || p->post_handler) | |
859 | unoptimize_kprobe(ap); /* Fall back to normal kprobe */ | |
860 | ||
8b0914ea | 861 | if (p->break_handler) { |
b918e5e6 | 862 | if (ap->break_handler) |
36721656 | 863 | return -EEXIST; |
b918e5e6 MH |
864 | list_add_tail_rcu(&p->list, &ap->list); |
865 | ap->break_handler = aggr_break_handler; | |
8b0914ea | 866 | } else |
b918e5e6 MH |
867 | list_add_rcu(&p->list, &ap->list); |
868 | if (p->post_handler && !ap->post_handler) | |
869 | ap->post_handler = aggr_post_handler; | |
de5bd88d MH |
870 | |
871 | if (kprobe_disabled(ap) && !kprobe_disabled(p)) { | |
872 | ap->flags &= ~KPROBE_FLAG_DISABLED; | |
873 | if (!kprobes_all_disarmed) | |
874 | /* Arm the breakpoint again. */ | |
afd66255 | 875 | __arm_kprobe(ap); |
de5bd88d | 876 | } |
8b0914ea PP |
877 | return 0; |
878 | } | |
879 | ||
64f562c6 AM |
880 | /* |
881 | * Fill in the required fields of the "manager kprobe". Replace the | |
882 | * earlier kprobe in the hlist with the manager kprobe | |
883 | */ | |
afd66255 | 884 | static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6 | 885 | { |
afd66255 | 886 | /* Copy p's insn slot to ap */ |
8b0914ea | 887 | copy_kprobe(p, ap); |
a9ad965e | 888 | flush_insn_slot(ap); |
64f562c6 | 889 | ap->addr = p->addr; |
afd66255 | 890 | ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6 | 891 | ap->pre_handler = aggr_pre_handler; |
64f562c6 | 892 | ap->fault_handler = aggr_fault_handler; |
e8386a0c MH |
893 | /* We don't care the kprobe which has gone. */ |
894 | if (p->post_handler && !kprobe_gone(p)) | |
36721656 | 895 | ap->post_handler = aggr_post_handler; |
e8386a0c | 896 | if (p->break_handler && !kprobe_gone(p)) |
36721656 | 897 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
898 | |
899 | INIT_LIST_HEAD(&ap->list); | |
afd66255 | 900 | INIT_HLIST_NODE(&ap->hlist); |
64f562c6 | 901 | |
afd66255 | 902 | list_add_rcu(&p->list, &ap->list); |
adad0f33 | 903 | hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6 AM |
904 | } |
905 | ||
906 | /* | |
907 | * This is the second or subsequent kprobe at the address - handle | |
908 | * the intricacies | |
64f562c6 | 909 | */ |
d0aaff97 PP |
910 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
911 | struct kprobe *p) | |
64f562c6 AM |
912 | { |
913 | int ret = 0; | |
b918e5e6 | 914 | struct kprobe *ap = old_p; |
64f562c6 | 915 | |
afd66255 MH |
916 | if (!kprobe_aggrprobe(old_p)) { |
917 | /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */ | |
918 | ap = alloc_aggr_kprobe(old_p); | |
b918e5e6 MH |
919 | if (!ap) |
920 | return -ENOMEM; | |
afd66255 | 921 | init_aggr_kprobe(ap, old_p); |
b918e5e6 MH |
922 | } |
923 | ||
924 | if (kprobe_gone(ap)) { | |
e8386a0c MH |
925 | /* |
926 | * Attempting to insert new probe at the same location that | |
927 | * had a probe in the module vaddr area which already | |
928 | * freed. So, the instruction slot has already been | |
929 | * released. We need a new slot for the new probe. | |
930 | */ | |
b918e5e6 | 931 | ret = arch_prepare_kprobe(ap); |
e8386a0c | 932 | if (ret) |
b918e5e6 MH |
933 | /* |
934 | * Even if fail to allocate new slot, don't need to | |
935 | * free aggr_probe. It will be used next time, or | |
936 | * freed by unregister_kprobe. | |
937 | */ | |
e8386a0c | 938 | return ret; |
de5bd88d | 939 | |
afd66255 MH |
940 | /* Prepare optimized instructions if possible. */ |
941 | prepare_optimized_kprobe(ap); | |
942 | ||
e8386a0c | 943 | /* |
de5bd88d MH |
944 | * Clear gone flag to prevent allocating new slot again, and |
945 | * set disabled flag because it is not armed yet. | |
e8386a0c | 946 | */ |
de5bd88d MH |
947 | ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) |
948 | | KPROBE_FLAG_DISABLED; | |
e8386a0c | 949 | } |
b918e5e6 | 950 | |
afd66255 | 951 | /* Copy ap's insn slot to p */ |
b918e5e6 MH |
952 | copy_kprobe(ap, p); |
953 | return add_new_kprobe(ap, p); | |
64f562c6 AM |
954 | } |
955 | ||
de5bd88d MH |
956 | /* Try to disable aggr_kprobe, and return 1 if succeeded.*/ |
957 | static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p) | |
958 | { | |
959 | struct kprobe *kp; | |
960 | ||
961 | list_for_each_entry_rcu(kp, &p->list, list) { | |
962 | if (!kprobe_disabled(kp)) | |
963 | /* | |
964 | * There is an active probe on the list. | |
965 | * We can't disable aggr_kprobe. | |
966 | */ | |
967 | return 0; | |
968 | } | |
969 | p->flags |= KPROBE_FLAG_DISABLED; | |
970 | return 1; | |
971 | } | |
972 | ||
d0aaff97 PP |
973 | static int __kprobes in_kprobes_functions(unsigned long addr) |
974 | { | |
3d8d996e SD |
975 | struct kprobe_blackpoint *kb; |
976 | ||
6f716acd CH |
977 | if (addr >= (unsigned long)__kprobes_text_start && |
978 | addr < (unsigned long)__kprobes_text_end) | |
d0aaff97 | 979 | return -EINVAL; |
3d8d996e SD |
980 | /* |
981 | * If there exists a kprobe_blacklist, verify and | |
982 | * fail any probe registration in the prohibited area | |
983 | */ | |
984 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
985 | if (kb->start_addr) { | |
986 | if (addr >= kb->start_addr && | |
987 | addr < (kb->start_addr + kb->range)) | |
988 | return -EINVAL; | |
989 | } | |
990 | } | |
d0aaff97 PP |
991 | return 0; |
992 | } | |
993 | ||
b2a5cd69 MH |
994 | /* |
995 | * If we have a symbol_name argument, look it up and add the offset field | |
996 | * to it. This way, we can specify a relative address to a symbol. | |
997 | */ | |
998 | static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p) | |
999 | { | |
1000 | kprobe_opcode_t *addr = p->addr; | |
1001 | if (p->symbol_name) { | |
1002 | if (addr) | |
1003 | return NULL; | |
1004 | kprobe_lookup_name(p->symbol_name, addr); | |
1005 | } | |
1006 | ||
1007 | if (!addr) | |
1008 | return NULL; | |
1009 | return (kprobe_opcode_t *)(((char *)addr) + p->offset); | |
1010 | } | |
1011 | ||
1f0ab409 AM |
1012 | /* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
1013 | static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p) | |
1014 | { | |
1015 | struct kprobe *old_p, *list_p; | |
1016 | ||
1017 | old_p = get_kprobe(p->addr); | |
1018 | if (unlikely(!old_p)) | |
1019 | return NULL; | |
1020 | ||
1021 | if (p != old_p) { | |
1022 | list_for_each_entry_rcu(list_p, &old_p->list, list) | |
1023 | if (list_p == p) | |
1024 | /* kprobe p is a valid probe */ | |
1025 | goto valid; | |
1026 | return NULL; | |
1027 | } | |
1028 | valid: | |
1029 | return old_p; | |
1030 | } | |
1031 | ||
1032 | /* Return error if the kprobe is being re-registered */ | |
1033 | static inline int check_kprobe_rereg(struct kprobe *p) | |
1034 | { | |
1035 | int ret = 0; | |
1036 | struct kprobe *old_p; | |
1037 | ||
1038 | mutex_lock(&kprobe_mutex); | |
1039 | old_p = __get_valid_kprobe(p); | |
1040 | if (old_p) | |
1041 | ret = -EINVAL; | |
1042 | mutex_unlock(&kprobe_mutex); | |
1043 | return ret; | |
1044 | } | |
1045 | ||
49ad2fd7 | 1046 | int __kprobes register_kprobe(struct kprobe *p) |
1da177e4 LT |
1047 | { |
1048 | int ret = 0; | |
64f562c6 | 1049 | struct kprobe *old_p; |
df019b1d | 1050 | struct module *probed_mod; |
b2a5cd69 | 1051 | kprobe_opcode_t *addr; |
b3e55c72 | 1052 | |
b2a5cd69 MH |
1053 | addr = kprobe_addr(p); |
1054 | if (!addr) | |
3a872d89 | 1055 | return -EINVAL; |
b2a5cd69 | 1056 | p->addr = addr; |
3a872d89 | 1057 | |
1f0ab409 AM |
1058 | ret = check_kprobe_rereg(p); |
1059 | if (ret) | |
1060 | return ret; | |
1061 | ||
a189d035 | 1062 | preempt_disable(); |
ec30c5f3 | 1063 | if (!kernel_text_address((unsigned long) p->addr) || |
4554dbcb MH |
1064 | in_kprobes_functions((unsigned long) p->addr) || |
1065 | ftrace_text_reserved(p->addr, p->addr)) { | |
a189d035 | 1066 | preempt_enable(); |
b3e55c72 | 1067 | return -EINVAL; |
a189d035 | 1068 | } |
b3e55c72 | 1069 | |
de5bd88d MH |
1070 | /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ |
1071 | p->flags &= KPROBE_FLAG_DISABLED; | |
1072 | ||
6f716acd CH |
1073 | /* |
1074 | * Check if are we probing a module. | |
1075 | */ | |
a189d035 | 1076 | probed_mod = __module_text_address((unsigned long) p->addr); |
6f716acd | 1077 | if (probed_mod) { |
6f716acd | 1078 | /* |
e8386a0c MH |
1079 | * We must hold a refcount of the probed module while updating |
1080 | * its code to prohibit unexpected unloading. | |
df019b1d | 1081 | */ |
49ad2fd7 MH |
1082 | if (unlikely(!try_module_get(probed_mod))) { |
1083 | preempt_enable(); | |
1084 | return -EINVAL; | |
1085 | } | |
f24659d9 MH |
1086 | /* |
1087 | * If the module freed .init.text, we couldn't insert | |
1088 | * kprobes in there. | |
1089 | */ | |
1090 | if (within_module_init((unsigned long)p->addr, probed_mod) && | |
1091 | probed_mod->state != MODULE_STATE_COMING) { | |
1092 | module_put(probed_mod); | |
1093 | preempt_enable(); | |
1094 | return -EINVAL; | |
1095 | } | |
df019b1d | 1096 | } |
a189d035 | 1097 | preempt_enable(); |
1da177e4 | 1098 | |
3516a460 | 1099 | p->nmissed = 0; |
9861668f | 1100 | INIT_LIST_HEAD(&p->list); |
7a7d1cf9 | 1101 | mutex_lock(&kprobe_mutex); |
afd66255 MH |
1102 | |
1103 | get_online_cpus(); /* For avoiding text_mutex deadlock. */ | |
1104 | mutex_lock(&text_mutex); | |
1105 | ||
64f562c6 AM |
1106 | old_p = get_kprobe(p->addr); |
1107 | if (old_p) { | |
afd66255 | 1108 | /* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6 | 1109 | ret = register_aggr_kprobe(old_p, p); |
1da177e4 LT |
1110 | goto out; |
1111 | } | |
1da177e4 | 1112 | |
6f716acd CH |
1113 | ret = arch_prepare_kprobe(p); |
1114 | if (ret) | |
afd66255 | 1115 | goto out; |
49a2a1b8 | 1116 | |
64f562c6 | 1117 | INIT_HLIST_NODE(&p->hlist); |
3516a460 | 1118 | hlist_add_head_rcu(&p->hlist, |
1da177e4 LT |
1119 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
1120 | ||
de5bd88d | 1121 | if (!kprobes_all_disarmed && !kprobe_disabled(p)) |
afd66255 MH |
1122 | __arm_kprobe(p); |
1123 | ||
1124 | /* Try to optimize kprobe */ | |
1125 | try_to_optimize_kprobe(p); | |
74a0b576 | 1126 | |
1da177e4 | 1127 | out: |
afd66255 MH |
1128 | mutex_unlock(&text_mutex); |
1129 | put_online_cpus(); | |
7a7d1cf9 | 1130 | mutex_unlock(&kprobe_mutex); |
49a2a1b8 | 1131 | |
e8386a0c | 1132 | if (probed_mod) |
df019b1d | 1133 | module_put(probed_mod); |
e8386a0c | 1134 | |
1da177e4 LT |
1135 | return ret; |
1136 | } | |
99081ab5 | 1137 | EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4 | 1138 | |
de5bd88d MH |
1139 | /* |
1140 | * Unregister a kprobe without a scheduler synchronization. | |
1141 | */ | |
1142 | static int __kprobes __unregister_kprobe_top(struct kprobe *p) | |
1143 | { | |
1144 | struct kprobe *old_p, *list_p; | |
1145 | ||
1146 | old_p = __get_valid_kprobe(p); | |
1147 | if (old_p == NULL) | |
1148 | return -EINVAL; | |
1149 | ||
6f716acd | 1150 | if (old_p == p || |
afd66255 | 1151 | (kprobe_aggrprobe(old_p) && |
9861668f | 1152 | list_is_singular(&old_p->list))) { |
bf8f6e5b AM |
1153 | /* |
1154 | * Only probe on the hash list. Disarm only if kprobes are | |
e8386a0c MH |
1155 | * enabled and not gone - otherwise, the breakpoint would |
1156 | * already have been removed. We save on flushing icache. | |
bf8f6e5b | 1157 | */ |
201517a7 | 1158 | if (!kprobes_all_disarmed && !kprobe_disabled(old_p)) |
afd66255 | 1159 | disarm_kprobe(old_p); |
49a2a1b8 | 1160 | hlist_del_rcu(&old_p->hlist); |
49a2a1b8 | 1161 | } else { |
e8386a0c | 1162 | if (p->break_handler && !kprobe_gone(p)) |
9861668f | 1163 | old_p->break_handler = NULL; |
e8386a0c | 1164 | if (p->post_handler && !kprobe_gone(p)) { |
9861668f MH |
1165 | list_for_each_entry_rcu(list_p, &old_p->list, list) { |
1166 | if ((list_p != p) && (list_p->post_handler)) | |
1167 | goto noclean; | |
1168 | } | |
1169 | old_p->post_handler = NULL; | |
1170 | } | |
1171 | noclean: | |
49a2a1b8 | 1172 | list_del_rcu(&p->list); |
de5bd88d MH |
1173 | if (!kprobe_disabled(old_p)) { |
1174 | try_to_disable_aggr_kprobe(old_p); | |
afd66255 MH |
1175 | if (!kprobes_all_disarmed) { |
1176 | if (kprobe_disabled(old_p)) | |
1177 | disarm_kprobe(old_p); | |
1178 | else | |
1179 | /* Try to optimize this probe again */ | |
1180 | optimize_kprobe(old_p); | |
1181 | } | |
de5bd88d | 1182 | } |
49a2a1b8 | 1183 | } |
9861668f MH |
1184 | return 0; |
1185 | } | |
3516a460 | 1186 | |
9861668f MH |
1187 | static void __kprobes __unregister_kprobe_bottom(struct kprobe *p) |
1188 | { | |
9861668f | 1189 | struct kprobe *old_p; |
b3e55c72 | 1190 | |
e8386a0c | 1191 | if (list_empty(&p->list)) |
0498b635 | 1192 | arch_remove_kprobe(p); |
e8386a0c MH |
1193 | else if (list_is_singular(&p->list)) { |
1194 | /* "p" is the last child of an aggr_kprobe */ | |
1195 | old_p = list_entry(p->list.next, struct kprobe, list); | |
1196 | list_del(&p->list); | |
1197 | arch_remove_kprobe(old_p); | |
afd66255 | 1198 | free_aggr_kprobe(old_p); |
9861668f MH |
1199 | } |
1200 | } | |
1201 | ||
49ad2fd7 | 1202 | int __kprobes register_kprobes(struct kprobe **kps, int num) |
9861668f MH |
1203 | { |
1204 | int i, ret = 0; | |
1205 | ||
1206 | if (num <= 0) | |
1207 | return -EINVAL; | |
1208 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1209 | ret = register_kprobe(kps[i]); |
67dddaad MH |
1210 | if (ret < 0) { |
1211 | if (i > 0) | |
1212 | unregister_kprobes(kps, i); | |
9861668f | 1213 | break; |
36721656 | 1214 | } |
49a2a1b8 | 1215 | } |
9861668f MH |
1216 | return ret; |
1217 | } | |
99081ab5 | 1218 | EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f | 1219 | |
9861668f MH |
1220 | void __kprobes unregister_kprobe(struct kprobe *p) |
1221 | { | |
1222 | unregister_kprobes(&p, 1); | |
1223 | } | |
99081ab5 | 1224 | EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f | 1225 | |
9861668f MH |
1226 | void __kprobes unregister_kprobes(struct kprobe **kps, int num) |
1227 | { | |
1228 | int i; | |
1229 | ||
1230 | if (num <= 0) | |
1231 | return; | |
1232 | mutex_lock(&kprobe_mutex); | |
1233 | for (i = 0; i < num; i++) | |
1234 | if (__unregister_kprobe_top(kps[i]) < 0) | |
1235 | kps[i]->addr = NULL; | |
1236 | mutex_unlock(&kprobe_mutex); | |
1237 | ||
1238 | synchronize_sched(); | |
1239 | for (i = 0; i < num; i++) | |
1240 | if (kps[i]->addr) | |
1241 | __unregister_kprobe_bottom(kps[i]); | |
1da177e4 | 1242 | } |
99081ab5 | 1243 | EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4 LT |
1244 | |
1245 | static struct notifier_block kprobe_exceptions_nb = { | |
3d5631e0 AK |
1246 | .notifier_call = kprobe_exceptions_notify, |
1247 | .priority = 0x7fffffff /* we need to be notified first */ | |
1248 | }; | |
1249 | ||
3d7e3382 ME |
1250 | unsigned long __weak arch_deref_entry_point(void *entry) |
1251 | { | |
1252 | return (unsigned long)entry; | |
1253 | } | |
1da177e4 | 1254 | |
49ad2fd7 | 1255 | int __kprobes register_jprobes(struct jprobe **jps, int num) |
1da177e4 | 1256 | { |
26b31c19 MH |
1257 | struct jprobe *jp; |
1258 | int ret = 0, i; | |
3d7e3382 | 1259 | |
26b31c19 | 1260 | if (num <= 0) |
3d7e3382 | 1261 | return -EINVAL; |
26b31c19 MH |
1262 | for (i = 0; i < num; i++) { |
1263 | unsigned long addr; | |
1264 | jp = jps[i]; | |
1265 | addr = arch_deref_entry_point(jp->entry); | |
1266 | ||
1267 | if (!kernel_text_address(addr)) | |
1268 | ret = -EINVAL; | |
1269 | else { | |
1270 | /* Todo: Verify probepoint is a function entry point */ | |
1271 | jp->kp.pre_handler = setjmp_pre_handler; | |
1272 | jp->kp.break_handler = longjmp_break_handler; | |
49ad2fd7 | 1273 | ret = register_kprobe(&jp->kp); |
26b31c19 | 1274 | } |
67dddaad MH |
1275 | if (ret < 0) { |
1276 | if (i > 0) | |
1277 | unregister_jprobes(jps, i); | |
26b31c19 MH |
1278 | break; |
1279 | } | |
1280 | } | |
1281 | return ret; | |
1282 | } | |
99081ab5 | 1283 | EXPORT_SYMBOL_GPL(register_jprobes); |
3d7e3382 | 1284 | |
26b31c19 MH |
1285 | int __kprobes register_jprobe(struct jprobe *jp) |
1286 | { | |
49ad2fd7 | 1287 | return register_jprobes(&jp, 1); |
1da177e4 | 1288 | } |
99081ab5 | 1289 | EXPORT_SYMBOL_GPL(register_jprobe); |
1da177e4 | 1290 | |
d0aaff97 | 1291 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 | 1292 | { |
26b31c19 MH |
1293 | unregister_jprobes(&jp, 1); |
1294 | } | |
99081ab5 | 1295 | EXPORT_SYMBOL_GPL(unregister_jprobe); |
26b31c19 | 1296 | |
26b31c19 MH |
1297 | void __kprobes unregister_jprobes(struct jprobe **jps, int num) |
1298 | { | |
1299 | int i; | |
1300 | ||
1301 | if (num <= 0) | |
1302 | return; | |
1303 | mutex_lock(&kprobe_mutex); | |
1304 | for (i = 0; i < num; i++) | |
1305 | if (__unregister_kprobe_top(&jps[i]->kp) < 0) | |
1306 | jps[i]->kp.addr = NULL; | |
1307 | mutex_unlock(&kprobe_mutex); | |
1308 | ||
1309 | synchronize_sched(); | |
1310 | for (i = 0; i < num; i++) { | |
1311 | if (jps[i]->kp.addr) | |
1312 | __unregister_kprobe_bottom(&jps[i]->kp); | |
1313 | } | |
1da177e4 | 1314 | } |
99081ab5 | 1315 | EXPORT_SYMBOL_GPL(unregister_jprobes); |
1da177e4 | 1316 | |
9edddaa2 | 1317 | #ifdef CONFIG_KRETPROBES |
e65cefe8 AB |
1318 | /* |
1319 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
1320 | * hits it will set up the return probe. | |
1321 | */ | |
1322 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, | |
1323 | struct pt_regs *regs) | |
1324 | { | |
1325 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
ef53d9c5 S |
1326 | unsigned long hash, flags = 0; |
1327 | struct kretprobe_instance *ri; | |
e65cefe8 AB |
1328 | |
1329 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
ef53d9c5 S |
1330 | hash = hash_ptr(current, KPROBE_HASH_BITS); |
1331 | spin_lock_irqsave(&rp->lock, flags); | |
4c4308cb | 1332 | if (!hlist_empty(&rp->free_instances)) { |
4c4308cb | 1333 | ri = hlist_entry(rp->free_instances.first, |
ef53d9c5 S |
1334 | struct kretprobe_instance, hlist); |
1335 | hlist_del(&ri->hlist); | |
1336 | spin_unlock_irqrestore(&rp->lock, flags); | |
1337 | ||
4c4308cb CH |
1338 | ri->rp = rp; |
1339 | ri->task = current; | |
f47cd9b5 | 1340 | |
f02b8624 | 1341 | if (rp->entry_handler && rp->entry_handler(ri, regs)) |
f47cd9b5 | 1342 | return 0; |
f47cd9b5 | 1343 | |
4c4308cb CH |
1344 | arch_prepare_kretprobe(ri, regs); |
1345 | ||
1346 | /* XXX(hch): why is there no hlist_move_head? */ | |
ef53d9c5 S |
1347 | INIT_HLIST_NODE(&ri->hlist); |
1348 | kretprobe_table_lock(hash, &flags); | |
1349 | hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); | |
1350 | kretprobe_table_unlock(hash, &flags); | |
1351 | } else { | |
4c4308cb | 1352 | rp->nmissed++; |
ef53d9c5 S |
1353 | spin_unlock_irqrestore(&rp->lock, flags); |
1354 | } | |
e65cefe8 AB |
1355 | return 0; |
1356 | } | |
1357 | ||
49ad2fd7 | 1358 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1359 | { |
1360 | int ret = 0; | |
1361 | struct kretprobe_instance *inst; | |
1362 | int i; | |
b2a5cd69 | 1363 | void *addr; |
f438d914 MH |
1364 | |
1365 | if (kretprobe_blacklist_size) { | |
b2a5cd69 MH |
1366 | addr = kprobe_addr(&rp->kp); |
1367 | if (!addr) | |
1368 | return -EINVAL; | |
f438d914 MH |
1369 | |
1370 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1371 | if (kretprobe_blacklist[i].addr == addr) | |
1372 | return -EINVAL; | |
1373 | } | |
1374 | } | |
b94cce92 HN |
1375 | |
1376 | rp->kp.pre_handler = pre_handler_kretprobe; | |
7522a842 AM |
1377 | rp->kp.post_handler = NULL; |
1378 | rp->kp.fault_handler = NULL; | |
1379 | rp->kp.break_handler = NULL; | |
b94cce92 HN |
1380 | |
1381 | /* Pre-allocate memory for max kretprobe instances */ | |
1382 | if (rp->maxactive <= 0) { | |
1383 | #ifdef CONFIG_PREEMPT | |
c2ef6661 | 1384 | rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce92 | 1385 | #else |
4dae560f | 1386 | rp->maxactive = num_possible_cpus(); |
b94cce92 HN |
1387 | #endif |
1388 | } | |
ef53d9c5 | 1389 | spin_lock_init(&rp->lock); |
b94cce92 HN |
1390 | INIT_HLIST_HEAD(&rp->free_instances); |
1391 | for (i = 0; i < rp->maxactive; i++) { | |
f47cd9b5 AS |
1392 | inst = kmalloc(sizeof(struct kretprobe_instance) + |
1393 | rp->data_size, GFP_KERNEL); | |
b94cce92 HN |
1394 | if (inst == NULL) { |
1395 | free_rp_inst(rp); | |
1396 | return -ENOMEM; | |
1397 | } | |
ef53d9c5 S |
1398 | INIT_HLIST_NODE(&inst->hlist); |
1399 | hlist_add_head(&inst->hlist, &rp->free_instances); | |
b94cce92 HN |
1400 | } |
1401 | ||
1402 | rp->nmissed = 0; | |
1403 | /* Establish function entry probe point */ | |
49ad2fd7 | 1404 | ret = register_kprobe(&rp->kp); |
4a296e07 | 1405 | if (ret != 0) |
b94cce92 HN |
1406 | free_rp_inst(rp); |
1407 | return ret; | |
1408 | } | |
99081ab5 | 1409 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1410 | |
49ad2fd7 | 1411 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
4a296e07 MH |
1412 | { |
1413 | int ret = 0, i; | |
1414 | ||
1415 | if (num <= 0) | |
1416 | return -EINVAL; | |
1417 | for (i = 0; i < num; i++) { | |
49ad2fd7 | 1418 | ret = register_kretprobe(rps[i]); |
67dddaad MH |
1419 | if (ret < 0) { |
1420 | if (i > 0) | |
1421 | unregister_kretprobes(rps, i); | |
4a296e07 MH |
1422 | break; |
1423 | } | |
1424 | } | |
1425 | return ret; | |
1426 | } | |
99081ab5 | 1427 | EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07 | 1428 | |
4a296e07 MH |
1429 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
1430 | { | |
1431 | unregister_kretprobes(&rp, 1); | |
1432 | } | |
99081ab5 | 1433 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07 | 1434 | |
4a296e07 MH |
1435 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1436 | { | |
1437 | int i; | |
1438 | ||
1439 | if (num <= 0) | |
1440 | return; | |
1441 | mutex_lock(&kprobe_mutex); | |
1442 | for (i = 0; i < num; i++) | |
1443 | if (__unregister_kprobe_top(&rps[i]->kp) < 0) | |
1444 | rps[i]->kp.addr = NULL; | |
1445 | mutex_unlock(&kprobe_mutex); | |
1446 | ||
1447 | synchronize_sched(); | |
1448 | for (i = 0; i < num; i++) { | |
1449 | if (rps[i]->kp.addr) { | |
1450 | __unregister_kprobe_bottom(&rps[i]->kp); | |
1451 | cleanup_rp_inst(rps[i]); | |
1452 | } | |
1453 | } | |
1454 | } | |
99081ab5 | 1455 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07 | 1456 | |
9edddaa2 | 1457 | #else /* CONFIG_KRETPROBES */ |
d0aaff97 | 1458 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
1459 | { |
1460 | return -ENOSYS; | |
1461 | } | |
99081ab5 | 1462 | EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce92 | 1463 | |
4a296e07 | 1464 | int __kprobes register_kretprobes(struct kretprobe **rps, int num) |
346fd59b | 1465 | { |
4a296e07 | 1466 | return -ENOSYS; |
346fd59b | 1467 | } |
99081ab5 MH |
1468 | EXPORT_SYMBOL_GPL(register_kretprobes); |
1469 | ||
d0aaff97 | 1470 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 | 1471 | { |
4a296e07 | 1472 | } |
99081ab5 | 1473 | EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce92 | 1474 | |
4a296e07 MH |
1475 | void __kprobes unregister_kretprobes(struct kretprobe **rps, int num) |
1476 | { | |
1477 | } | |
99081ab5 | 1478 | EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb | 1479 | |
4a296e07 MH |
1480 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
1481 | struct pt_regs *regs) | |
1482 | { | |
1483 | return 0; | |
b94cce92 HN |
1484 | } |
1485 | ||
4a296e07 MH |
1486 | #endif /* CONFIG_KRETPROBES */ |
1487 | ||
e8386a0c MH |
1488 | /* Set the kprobe gone and remove its instruction buffer. */ |
1489 | static void __kprobes kill_kprobe(struct kprobe *p) | |
1490 | { | |
1491 | struct kprobe *kp; | |
de5bd88d | 1492 | |
e8386a0c | 1493 | p->flags |= KPROBE_FLAG_GONE; |
afd66255 | 1494 | if (kprobe_aggrprobe(p)) { |
e8386a0c MH |
1495 | /* |
1496 | * If this is an aggr_kprobe, we have to list all the | |
1497 | * chained probes and mark them GONE. | |
1498 | */ | |
1499 | list_for_each_entry_rcu(kp, &p->list, list) | |
1500 | kp->flags |= KPROBE_FLAG_GONE; | |
1501 | p->post_handler = NULL; | |
1502 | p->break_handler = NULL; | |
afd66255 | 1503 | kill_optimized_kprobe(p); |
e8386a0c MH |
1504 | } |
1505 | /* | |
1506 | * Here, we can remove insn_slot safely, because no thread calls | |
1507 | * the original probed function (which will be freed soon) any more. | |
1508 | */ | |
1509 | arch_remove_kprobe(p); | |
1510 | } | |
1511 | ||
24851d24 FW |
1512 | void __kprobes dump_kprobe(struct kprobe *kp) |
1513 | { | |
1514 | printk(KERN_WARNING "Dumping kprobe:\n"); | |
1515 | printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n", | |
1516 | kp->symbol_name, kp->addr, kp->offset); | |
1517 | } | |
1518 | ||
e8386a0c MH |
1519 | /* Module notifier call back, checking kprobes on the module */ |
1520 | static int __kprobes kprobes_module_callback(struct notifier_block *nb, | |
1521 | unsigned long val, void *data) | |
1522 | { | |
1523 | struct module *mod = data; | |
1524 | struct hlist_head *head; | |
1525 | struct hlist_node *node; | |
1526 | struct kprobe *p; | |
1527 | unsigned int i; | |
f24659d9 | 1528 | int checkcore = (val == MODULE_STATE_GOING); |
e8386a0c | 1529 | |
f24659d9 | 1530 | if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0c MH |
1531 | return NOTIFY_DONE; |
1532 | ||
1533 | /* | |
f24659d9 MH |
1534 | * When MODULE_STATE_GOING was notified, both of module .text and |
1535 | * .init.text sections would be freed. When MODULE_STATE_LIVE was | |
1536 | * notified, only .init.text section would be freed. We need to | |
1537 | * disable kprobes which have been inserted in the sections. | |
e8386a0c MH |
1538 | */ |
1539 | mutex_lock(&kprobe_mutex); | |
1540 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { | |
1541 | head = &kprobe_table[i]; | |
1542 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
f24659d9 MH |
1543 | if (within_module_init((unsigned long)p->addr, mod) || |
1544 | (checkcore && | |
1545 | within_module_core((unsigned long)p->addr, mod))) { | |
e8386a0c MH |
1546 | /* |
1547 | * The vaddr this probe is installed will soon | |
1548 | * be vfreed buy not synced to disk. Hence, | |
1549 | * disarming the breakpoint isn't needed. | |
1550 | */ | |
1551 | kill_kprobe(p); | |
1552 | } | |
1553 | } | |
1554 | mutex_unlock(&kprobe_mutex); | |
1555 | return NOTIFY_DONE; | |
1556 | } | |
1557 | ||
1558 | static struct notifier_block kprobe_module_nb = { | |
1559 | .notifier_call = kprobes_module_callback, | |
1560 | .priority = 0 | |
1561 | }; | |
1562 | ||
1da177e4 LT |
1563 | static int __init init_kprobes(void) |
1564 | { | |
1565 | int i, err = 0; | |
3d8d996e SD |
1566 | unsigned long offset = 0, size = 0; |
1567 | char *modname, namebuf[128]; | |
1568 | const char *symbol_name; | |
1569 | void *addr; | |
1570 | struct kprobe_blackpoint *kb; | |
1da177e4 LT |
1571 | |
1572 | /* FIXME allocate the probe table, currently defined statically */ | |
1573 | /* initialize all list heads */ | |
b94cce92 | 1574 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 1575 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 | 1576 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ef53d9c5 | 1577 | spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce92 | 1578 | } |
1da177e4 | 1579 | |
3d8d996e SD |
1580 | /* |
1581 | * Lookup and populate the kprobe_blacklist. | |
1582 | * | |
1583 | * Unlike the kretprobe blacklist, we'll need to determine | |
1584 | * the range of addresses that belong to the said functions, | |
1585 | * since a kprobe need not necessarily be at the beginning | |
1586 | * of a function. | |
1587 | */ | |
1588 | for (kb = kprobe_blacklist; kb->name != NULL; kb++) { | |
1589 | kprobe_lookup_name(kb->name, addr); | |
1590 | if (!addr) | |
1591 | continue; | |
1592 | ||
1593 | kb->start_addr = (unsigned long)addr; | |
1594 | symbol_name = kallsyms_lookup(kb->start_addr, | |
1595 | &size, &offset, &modname, namebuf); | |
1596 | if (!symbol_name) | |
1597 | kb->range = 0; | |
1598 | else | |
1599 | kb->range = size; | |
1600 | } | |
1601 | ||
f438d914 MH |
1602 | if (kretprobe_blacklist_size) { |
1603 | /* lookup the function address from its name */ | |
1604 | for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { | |
1605 | kprobe_lookup_name(kretprobe_blacklist[i].name, | |
1606 | kretprobe_blacklist[i].addr); | |
1607 | if (!kretprobe_blacklist[i].addr) | |
1608 | printk("kretprobe: lookup failed: %s\n", | |
1609 | kretprobe_blacklist[i].name); | |
1610 | } | |
1611 | } | |
1612 | ||
afd66255 MH |
1613 | #if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
1614 | /* Init kprobe_optinsn_slots */ | |
1615 | kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; | |
1616 | #endif | |
1617 | ||
e579abeb MH |
1618 | /* By default, kprobes are armed */ |
1619 | kprobes_all_disarmed = false; | |
bf8f6e5b | 1620 | |
6772926b | 1621 | err = arch_init_kprobes(); |
802eae7c RL |
1622 | if (!err) |
1623 | err = register_die_notifier(&kprobe_exceptions_nb); | |
e8386a0c MH |
1624 | if (!err) |
1625 | err = register_module_notifier(&kprobe_module_nb); | |
1626 | ||
ef53d9c5 | 1627 | kprobes_initialized = (err == 0); |
802eae7c | 1628 | |
8c1c9356 AM |
1629 | if (!err) |
1630 | init_test_probes(); | |
1da177e4 LT |
1631 | return err; |
1632 | } | |
1633 | ||
346fd59b SD |
1634 | #ifdef CONFIG_DEBUG_FS |
1635 | static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, | |
afd66255 | 1636 | const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59b SD |
1637 | { |
1638 | char *kprobe_type; | |
1639 | ||
1640 | if (p->pre_handler == pre_handler_kretprobe) | |
1641 | kprobe_type = "r"; | |
1642 | else if (p->pre_handler == setjmp_pre_handler) | |
1643 | kprobe_type = "j"; | |
1644 | else | |
1645 | kprobe_type = "k"; | |
afd66255 | 1646 | |
346fd59b | 1647 | if (sym) |
afd66255 | 1648 | seq_printf(pi, "%p %s %s+0x%x %s ", |
de5bd88d | 1649 | p->addr, kprobe_type, sym, offset, |
afd66255 | 1650 | (modname ? modname : " ")); |
346fd59b | 1651 | else |
afd66255 MH |
1652 | seq_printf(pi, "%p %s %p ", |
1653 | p->addr, kprobe_type, p->addr); | |
1654 | ||
1655 | if (!pp) | |
1656 | pp = p; | |
1657 | seq_printf(pi, "%s%s%s\n", | |
1658 | (kprobe_gone(p) ? "[GONE]" : ""), | |
1659 | ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), | |
1660 | (kprobe_optimized(pp) ? "[OPTIMIZED]" : "")); | |
346fd59b SD |
1661 | } |
1662 | ||
1663 | static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos) | |
1664 | { | |
1665 | return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; | |
1666 | } | |
1667 | ||
1668 | static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) | |
1669 | { | |
1670 | (*pos)++; | |
1671 | if (*pos >= KPROBE_TABLE_SIZE) | |
1672 | return NULL; | |
1673 | return pos; | |
1674 | } | |
1675 | ||
1676 | static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v) | |
1677 | { | |
1678 | /* Nothing to do */ | |
1679 | } | |
1680 | ||
1681 | static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v) | |
1682 | { | |
1683 | struct hlist_head *head; | |
1684 | struct hlist_node *node; | |
1685 | struct kprobe *p, *kp; | |
1686 | const char *sym = NULL; | |
1687 | unsigned int i = *(loff_t *) v; | |
ffb45122 | 1688 | unsigned long offset = 0; |
346fd59b SD |
1689 | char *modname, namebuf[128]; |
1690 | ||
1691 | head = &kprobe_table[i]; | |
1692 | preempt_disable(); | |
1693 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
ffb45122 | 1694 | sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59b | 1695 | &offset, &modname, namebuf); |
afd66255 | 1696 | if (kprobe_aggrprobe(p)) { |
346fd59b | 1697 | list_for_each_entry_rcu(kp, &p->list, list) |
afd66255 | 1698 | report_probe(pi, kp, sym, offset, modname, p); |
346fd59b | 1699 | } else |
afd66255 | 1700 | report_probe(pi, p, sym, offset, modname, NULL); |
346fd59b SD |
1701 | } |
1702 | preempt_enable(); | |
1703 | return 0; | |
1704 | } | |
1705 | ||
88e9d34c | 1706 | static const struct seq_operations kprobes_seq_ops = { |
346fd59b SD |
1707 | .start = kprobe_seq_start, |
1708 | .next = kprobe_seq_next, | |
1709 | .stop = kprobe_seq_stop, | |
1710 | .show = show_kprobe_addr | |
1711 | }; | |
1712 | ||
1713 | static int __kprobes kprobes_open(struct inode *inode, struct file *filp) | |
1714 | { | |
1715 | return seq_open(filp, &kprobes_seq_ops); | |
1716 | } | |
1717 | ||
828c0950 | 1718 | static const struct file_operations debugfs_kprobes_operations = { |
346fd59b SD |
1719 | .open = kprobes_open, |
1720 | .read = seq_read, | |
1721 | .llseek = seq_lseek, | |
1722 | .release = seq_release, | |
1723 | }; | |
1724 | ||
de5bd88d MH |
1725 | /* Disable one kprobe */ |
1726 | int __kprobes disable_kprobe(struct kprobe *kp) | |
1727 | { | |
1728 | int ret = 0; | |
1729 | struct kprobe *p; | |
1730 | ||
1731 | mutex_lock(&kprobe_mutex); | |
1732 | ||
1733 | /* Check whether specified probe is valid. */ | |
1734 | p = __get_valid_kprobe(kp); | |
1735 | if (unlikely(p == NULL)) { | |
1736 | ret = -EINVAL; | |
1737 | goto out; | |
1738 | } | |
1739 | ||
1740 | /* If the probe is already disabled (or gone), just return */ | |
1741 | if (kprobe_disabled(kp)) | |
1742 | goto out; | |
1743 | ||
1744 | kp->flags |= KPROBE_FLAG_DISABLED; | |
1745 | if (p != kp) | |
1746 | /* When kp != p, p is always enabled. */ | |
1747 | try_to_disable_aggr_kprobe(p); | |
1748 | ||
1749 | if (!kprobes_all_disarmed && kprobe_disabled(p)) | |
201517a7 | 1750 | disarm_kprobe(p); |
de5bd88d MH |
1751 | out: |
1752 | mutex_unlock(&kprobe_mutex); | |
1753 | return ret; | |
1754 | } | |
1755 | EXPORT_SYMBOL_GPL(disable_kprobe); | |
1756 | ||
1757 | /* Enable one kprobe */ | |
1758 | int __kprobes enable_kprobe(struct kprobe *kp) | |
1759 | { | |
1760 | int ret = 0; | |
1761 | struct kprobe *p; | |
1762 | ||
1763 | mutex_lock(&kprobe_mutex); | |
1764 | ||
1765 | /* Check whether specified probe is valid. */ | |
1766 | p = __get_valid_kprobe(kp); | |
1767 | if (unlikely(p == NULL)) { | |
1768 | ret = -EINVAL; | |
1769 | goto out; | |
1770 | } | |
1771 | ||
1772 | if (kprobe_gone(kp)) { | |
1773 | /* This kprobe has gone, we couldn't enable it. */ | |
1774 | ret = -EINVAL; | |
1775 | goto out; | |
1776 | } | |
1777 | ||
de5bd88d MH |
1778 | if (p != kp) |
1779 | kp->flags &= ~KPROBE_FLAG_DISABLED; | |
afd66255 MH |
1780 | |
1781 | if (!kprobes_all_disarmed && kprobe_disabled(p)) { | |
1782 | p->flags &= ~KPROBE_FLAG_DISABLED; | |
1783 | arm_kprobe(p); | |
1784 | } | |
de5bd88d MH |
1785 | out: |
1786 | mutex_unlock(&kprobe_mutex); | |
1787 | return ret; | |
1788 | } | |
1789 | EXPORT_SYMBOL_GPL(enable_kprobe); | |
1790 | ||
e579abeb | 1791 | static void __kprobes arm_all_kprobes(void) |
bf8f6e5b AM |
1792 | { |
1793 | struct hlist_head *head; | |
1794 | struct hlist_node *node; | |
1795 | struct kprobe *p; | |
1796 | unsigned int i; | |
1797 | ||
1798 | mutex_lock(&kprobe_mutex); | |
1799 | ||
e579abeb MH |
1800 | /* If kprobes are armed, just return */ |
1801 | if (!kprobes_all_disarmed) | |
bf8f6e5b AM |
1802 | goto already_enabled; |
1803 | ||
afd66255 | 1804 | /* Arming kprobes doesn't optimize kprobe itself */ |
4460fdad | 1805 | mutex_lock(&text_mutex); |
bf8f6e5b AM |
1806 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1807 | head = &kprobe_table[i]; | |
1808 | hlist_for_each_entry_rcu(p, node, head, hlist) | |
de5bd88d | 1809 | if (!kprobe_disabled(p)) |
afd66255 | 1810 | __arm_kprobe(p); |
bf8f6e5b | 1811 | } |
4460fdad | 1812 | mutex_unlock(&text_mutex); |
bf8f6e5b | 1813 | |
e579abeb | 1814 | kprobes_all_disarmed = false; |
bf8f6e5b AM |
1815 | printk(KERN_INFO "Kprobes globally enabled\n"); |
1816 | ||
1817 | already_enabled: | |
1818 | mutex_unlock(&kprobe_mutex); | |
1819 | return; | |
1820 | } | |
1821 | ||
e579abeb | 1822 | static void __kprobes disarm_all_kprobes(void) |
bf8f6e5b AM |
1823 | { |
1824 | struct hlist_head *head; | |
1825 | struct hlist_node *node; | |
1826 | struct kprobe *p; | |
1827 | unsigned int i; | |
1828 | ||
1829 | mutex_lock(&kprobe_mutex); | |
1830 | ||
e579abeb MH |
1831 | /* If kprobes are already disarmed, just return */ |
1832 | if (kprobes_all_disarmed) | |
bf8f6e5b AM |
1833 | goto already_disabled; |
1834 | ||
e579abeb | 1835 | kprobes_all_disarmed = true; |
bf8f6e5b | 1836 | printk(KERN_INFO "Kprobes globally disabled\n"); |
afd66255 MH |
1837 | |
1838 | /* | |
1839 | * Here we call get_online_cpus() for avoiding text_mutex deadlock, | |
1840 | * because disarming may also unoptimize kprobes. | |
1841 | */ | |
1842 | get_online_cpus(); | |
4460fdad | 1843 | mutex_lock(&text_mutex); |
bf8f6e5b AM |
1844 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1845 | head = &kprobe_table[i]; | |
1846 | hlist_for_each_entry_rcu(p, node, head, hlist) { | |
de5bd88d | 1847 | if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) |
afd66255 | 1848 | __disarm_kprobe(p); |
bf8f6e5b AM |
1849 | } |
1850 | } | |
1851 | ||
4460fdad | 1852 | mutex_unlock(&text_mutex); |
afd66255 | 1853 | put_online_cpus(); |
bf8f6e5b AM |
1854 | mutex_unlock(&kprobe_mutex); |
1855 | /* Allow all currently running kprobes to complete */ | |
1856 | synchronize_sched(); | |
74a0b576 | 1857 | return; |
bf8f6e5b AM |
1858 | |
1859 | already_disabled: | |
1860 | mutex_unlock(&kprobe_mutex); | |
1861 | return; | |
1862 | } | |
1863 | ||
1864 | /* | |
1865 | * XXX: The debugfs bool file interface doesn't allow for callbacks | |
1866 | * when the bool state is switched. We can reuse that facility when | |
1867 | * available | |
1868 | */ | |
1869 | static ssize_t read_enabled_file_bool(struct file *file, | |
1870 | char __user *user_buf, size_t count, loff_t *ppos) | |
1871 | { | |
1872 | char buf[3]; | |
1873 | ||
e579abeb | 1874 | if (!kprobes_all_disarmed) |
bf8f6e5b AM |
1875 | buf[0] = '1'; |
1876 | else | |
1877 | buf[0] = '0'; | |
1878 | buf[1] = '\n'; | |
1879 | buf[2] = 0x00; | |
1880 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2); | |
1881 | } | |
1882 | ||
1883 | static ssize_t write_enabled_file_bool(struct file *file, | |
1884 | const char __user *user_buf, size_t count, loff_t *ppos) | |
1885 | { | |
1886 | char buf[32]; | |
1887 | int buf_size; | |
1888 | ||
1889 | buf_size = min(count, (sizeof(buf)-1)); | |
1890 | if (copy_from_user(buf, user_buf, buf_size)) | |
1891 | return -EFAULT; | |
1892 | ||
1893 | switch (buf[0]) { | |
1894 | case 'y': | |
1895 | case 'Y': | |
1896 | case '1': | |
e579abeb | 1897 | arm_all_kprobes(); |
bf8f6e5b AM |
1898 | break; |
1899 | case 'n': | |
1900 | case 'N': | |
1901 | case '0': | |
e579abeb | 1902 | disarm_all_kprobes(); |
bf8f6e5b AM |
1903 | break; |
1904 | } | |
1905 | ||
1906 | return count; | |
1907 | } | |
1908 | ||
828c0950 | 1909 | static const struct file_operations fops_kp = { |
bf8f6e5b AM |
1910 | .read = read_enabled_file_bool, |
1911 | .write = write_enabled_file_bool, | |
1912 | }; | |
1913 | ||
346fd59b SD |
1914 | static int __kprobes debugfs_kprobe_init(void) |
1915 | { | |
1916 | struct dentry *dir, *file; | |
bf8f6e5b | 1917 | unsigned int value = 1; |
346fd59b SD |
1918 | |
1919 | dir = debugfs_create_dir("kprobes", NULL); | |
1920 | if (!dir) | |
1921 | return -ENOMEM; | |
1922 | ||
e3869792 | 1923 | file = debugfs_create_file("list", 0444, dir, NULL, |
346fd59b SD |
1924 | &debugfs_kprobes_operations); |
1925 | if (!file) { | |
1926 | debugfs_remove(dir); | |
1927 | return -ENOMEM; | |
1928 | } | |
1929 | ||
bf8f6e5b AM |
1930 | file = debugfs_create_file("enabled", 0600, dir, |
1931 | &value, &fops_kp); | |
1932 | if (!file) { | |
1933 | debugfs_remove(dir); | |
1934 | return -ENOMEM; | |
1935 | } | |
1936 | ||
346fd59b SD |
1937 | return 0; |
1938 | } | |
1939 | ||
1940 | late_initcall(debugfs_kprobe_init); | |
1941 | #endif /* CONFIG_DEBUG_FS */ | |
1942 | ||
1943 | module_init(init_kprobes); | |
1da177e4 | 1944 | |
99081ab5 | 1945 | /* defined in arch/.../kernel/kprobes.c */ |
1da177e4 | 1946 | EXPORT_SYMBOL_GPL(jprobe_return); |