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> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/hash.h> | |
37 | #include <linux/init.h> | |
38 | #include <linux/module.h> | |
9ec4b1f3 | 39 | #include <linux/moduleloader.h> |
1da177e4 LT |
40 | #include <asm/cacheflush.h> |
41 | #include <asm/errno.h> | |
42 | #include <asm/kdebug.h> | |
43 | ||
44 | #define KPROBE_HASH_BITS 6 | |
45 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
46 | ||
47 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; | |
b94cce92 | 48 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 LT |
49 | |
50 | unsigned int kprobe_cpu = NR_CPUS; | |
51 | static DEFINE_SPINLOCK(kprobe_lock); | |
64f562c6 | 52 | static struct kprobe *curr_kprobe; |
1da177e4 | 53 | |
9ec4b1f3 AM |
54 | /* |
55 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
56 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
57 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
58 | * is a recipe for disaster | |
59 | */ | |
60 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) | |
61 | ||
62 | struct kprobe_insn_page { | |
63 | struct hlist_node hlist; | |
64 | kprobe_opcode_t *insns; /* Page of instruction slots */ | |
65 | char slot_used[INSNS_PER_PAGE]; | |
66 | int nused; | |
67 | }; | |
68 | ||
69 | static struct hlist_head kprobe_insn_pages; | |
70 | ||
71 | /** | |
72 | * get_insn_slot() - Find a slot on an executable page for an instruction. | |
73 | * We allocate an executable page if there's no room on existing ones. | |
74 | */ | |
75 | kprobe_opcode_t *get_insn_slot(void) | |
76 | { | |
77 | struct kprobe_insn_page *kip; | |
78 | struct hlist_node *pos; | |
79 | ||
80 | hlist_for_each(pos, &kprobe_insn_pages) { | |
81 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); | |
82 | if (kip->nused < INSNS_PER_PAGE) { | |
83 | int i; | |
84 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
85 | if (!kip->slot_used[i]) { | |
86 | kip->slot_used[i] = 1; | |
87 | kip->nused++; | |
88 | return kip->insns + (i * MAX_INSN_SIZE); | |
89 | } | |
90 | } | |
91 | /* Surprise! No unused slots. Fix kip->nused. */ | |
92 | kip->nused = INSNS_PER_PAGE; | |
93 | } | |
94 | } | |
95 | ||
96 | /* All out of space. Need to allocate a new page. Use slot 0.*/ | |
97 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); | |
98 | if (!kip) { | |
99 | return NULL; | |
100 | } | |
101 | ||
102 | /* | |
103 | * Use module_alloc so this page is within +/- 2GB of where the | |
104 | * kernel image and loaded module images reside. This is required | |
105 | * so x86_64 can correctly handle the %rip-relative fixups. | |
106 | */ | |
107 | kip->insns = module_alloc(PAGE_SIZE); | |
108 | if (!kip->insns) { | |
109 | kfree(kip); | |
110 | return NULL; | |
111 | } | |
112 | INIT_HLIST_NODE(&kip->hlist); | |
113 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); | |
114 | memset(kip->slot_used, 0, INSNS_PER_PAGE); | |
115 | kip->slot_used[0] = 1; | |
116 | kip->nused = 1; | |
117 | return kip->insns; | |
118 | } | |
119 | ||
120 | void free_insn_slot(kprobe_opcode_t *slot) | |
121 | { | |
122 | struct kprobe_insn_page *kip; | |
123 | struct hlist_node *pos; | |
124 | ||
125 | hlist_for_each(pos, &kprobe_insn_pages) { | |
126 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); | |
127 | if (kip->insns <= slot && | |
128 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
129 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
130 | kip->slot_used[i] = 0; | |
131 | kip->nused--; | |
132 | if (kip->nused == 0) { | |
133 | /* | |
134 | * Page is no longer in use. Free it unless | |
135 | * it's the last one. We keep the last one | |
136 | * so as not to have to set it up again the | |
137 | * next time somebody inserts a probe. | |
138 | */ | |
139 | hlist_del(&kip->hlist); | |
140 | if (hlist_empty(&kprobe_insn_pages)) { | |
141 | INIT_HLIST_NODE(&kip->hlist); | |
142 | hlist_add_head(&kip->hlist, | |
143 | &kprobe_insn_pages); | |
144 | } else { | |
145 | module_free(NULL, kip->insns); | |
146 | kfree(kip); | |
147 | } | |
148 | } | |
149 | return; | |
150 | } | |
151 | } | |
152 | } | |
153 | ||
1da177e4 LT |
154 | /* Locks kprobe: irqs must be disabled */ |
155 | void lock_kprobes(void) | |
156 | { | |
157 | spin_lock(&kprobe_lock); | |
158 | kprobe_cpu = smp_processor_id(); | |
159 | } | |
160 | ||
161 | void unlock_kprobes(void) | |
162 | { | |
163 | kprobe_cpu = NR_CPUS; | |
164 | spin_unlock(&kprobe_lock); | |
165 | } | |
166 | ||
167 | /* You have to be holding the kprobe_lock */ | |
168 | struct kprobe *get_kprobe(void *addr) | |
169 | { | |
170 | struct hlist_head *head; | |
171 | struct hlist_node *node; | |
172 | ||
173 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
174 | hlist_for_each(node, head) { | |
175 | struct kprobe *p = hlist_entry(node, struct kprobe, hlist); | |
176 | if (p->addr == addr) | |
177 | return p; | |
178 | } | |
179 | return NULL; | |
180 | } | |
181 | ||
64f562c6 AM |
182 | /* |
183 | * Aggregate handlers for multiple kprobes support - these handlers | |
184 | * take care of invoking the individual kprobe handlers on p->list | |
185 | */ | |
b94cce92 | 186 | static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
187 | { |
188 | struct kprobe *kp; | |
189 | ||
190 | list_for_each_entry(kp, &p->list, list) { | |
191 | if (kp->pre_handler) { | |
192 | curr_kprobe = kp; | |
8b0914ea PP |
193 | if (kp->pre_handler(kp, regs)) |
194 | return 1; | |
64f562c6 | 195 | } |
8b0914ea | 196 | curr_kprobe = NULL; |
64f562c6 AM |
197 | } |
198 | return 0; | |
199 | } | |
200 | ||
b94cce92 HN |
201 | static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
202 | unsigned long flags) | |
64f562c6 AM |
203 | { |
204 | struct kprobe *kp; | |
205 | ||
206 | list_for_each_entry(kp, &p->list, list) { | |
207 | if (kp->post_handler) { | |
208 | curr_kprobe = kp; | |
209 | kp->post_handler(kp, regs, flags); | |
210 | curr_kprobe = NULL; | |
211 | } | |
212 | } | |
213 | return; | |
214 | } | |
215 | ||
b94cce92 HN |
216 | static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
217 | int trapnr) | |
64f562c6 AM |
218 | { |
219 | /* | |
220 | * if we faulted "during" the execution of a user specified | |
221 | * probe handler, invoke just that probe's fault handler | |
222 | */ | |
223 | if (curr_kprobe && curr_kprobe->fault_handler) { | |
224 | if (curr_kprobe->fault_handler(curr_kprobe, regs, trapnr)) | |
225 | return 1; | |
226 | } | |
227 | return 0; | |
228 | } | |
229 | ||
8b0914ea PP |
230 | static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
231 | { | |
232 | struct kprobe *kp = curr_kprobe; | |
233 | if (curr_kprobe && kp->break_handler) { | |
234 | if (kp->break_handler(kp, regs)) { | |
235 | curr_kprobe = NULL; | |
236 | return 1; | |
237 | } | |
238 | } | |
239 | curr_kprobe = NULL; | |
240 | return 0; | |
241 | } | |
242 | ||
b94cce92 HN |
243 | struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp) |
244 | { | |
245 | struct hlist_node *node; | |
246 | struct kretprobe_instance *ri; | |
247 | hlist_for_each_entry(ri, node, &rp->free_instances, uflist) | |
248 | return ri; | |
249 | return NULL; | |
250 | } | |
251 | ||
252 | static struct kretprobe_instance *get_used_rp_inst(struct kretprobe *rp) | |
253 | { | |
254 | struct hlist_node *node; | |
255 | struct kretprobe_instance *ri; | |
256 | hlist_for_each_entry(ri, node, &rp->used_instances, uflist) | |
257 | return ri; | |
258 | return NULL; | |
259 | } | |
260 | ||
b94cce92 HN |
261 | void add_rp_inst(struct kretprobe_instance *ri) |
262 | { | |
b94cce92 HN |
263 | /* |
264 | * Remove rp inst off the free list - | |
265 | * Add it back when probed function returns | |
266 | */ | |
267 | hlist_del(&ri->uflist); | |
802eae7c | 268 | |
b94cce92 HN |
269 | /* Add rp inst onto table */ |
270 | INIT_HLIST_NODE(&ri->hlist); | |
271 | hlist_add_head(&ri->hlist, | |
802eae7c | 272 | &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]); |
b94cce92 HN |
273 | |
274 | /* Also add this rp inst to the used list. */ | |
275 | INIT_HLIST_NODE(&ri->uflist); | |
276 | hlist_add_head(&ri->uflist, &ri->rp->used_instances); | |
277 | } | |
278 | ||
279 | void recycle_rp_inst(struct kretprobe_instance *ri) | |
280 | { | |
281 | /* remove rp inst off the rprobe_inst_table */ | |
282 | hlist_del(&ri->hlist); | |
283 | if (ri->rp) { | |
284 | /* remove rp inst off the used list */ | |
285 | hlist_del(&ri->uflist); | |
286 | /* put rp inst back onto the free list */ | |
287 | INIT_HLIST_NODE(&ri->uflist); | |
288 | hlist_add_head(&ri->uflist, &ri->rp->free_instances); | |
289 | } else | |
290 | /* Unregistering */ | |
291 | kfree(ri); | |
292 | } | |
293 | ||
294 | struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk) | |
295 | { | |
296 | return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]; | |
297 | } | |
298 | ||
b94cce92 | 299 | /* |
802eae7c RL |
300 | * This function is called from exit_thread or flush_thread when task tk's |
301 | * stack is being recycled so that we can recycle any function-return probe | |
302 | * instances associated with this task. These left over instances represent | |
303 | * probed functions that have been called but will never return. | |
b94cce92 HN |
304 | */ |
305 | void kprobe_flush_task(struct task_struct *tk) | |
306 | { | |
802eae7c RL |
307 | struct kretprobe_instance *ri; |
308 | struct hlist_head *head; | |
309 | struct hlist_node *node, *tmp; | |
0aa55e4d | 310 | unsigned long flags = 0; |
802eae7c | 311 | |
0aa55e4d | 312 | spin_lock_irqsave(&kprobe_lock, flags); |
802eae7c RL |
313 | head = kretprobe_inst_table_head(current); |
314 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
315 | if (ri->task == tk) | |
316 | recycle_rp_inst(ri); | |
317 | } | |
0aa55e4d | 318 | spin_unlock_irqrestore(&kprobe_lock, flags); |
b94cce92 HN |
319 | } |
320 | ||
321 | /* | |
322 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
323 | * hits it will set up the return probe. | |
324 | */ | |
325 | static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) | |
326 | { | |
327 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
328 | ||
329 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
330 | arch_prepare_kretprobe(rp, regs); | |
331 | return 0; | |
332 | } | |
333 | ||
334 | static inline void free_rp_inst(struct kretprobe *rp) | |
335 | { | |
336 | struct kretprobe_instance *ri; | |
337 | while ((ri = get_free_rp_inst(rp)) != NULL) { | |
338 | hlist_del(&ri->uflist); | |
339 | kfree(ri); | |
340 | } | |
341 | } | |
342 | ||
8b0914ea PP |
343 | /* |
344 | * Keep all fields in the kprobe consistent | |
345 | */ | |
346 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
347 | { | |
348 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
349 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
350 | } | |
351 | ||
352 | /* | |
353 | * Add the new probe to old_p->list. Fail if this is the | |
354 | * second jprobe at the address - two jprobes can't coexist | |
355 | */ | |
356 | static int add_new_kprobe(struct kprobe *old_p, struct kprobe *p) | |
357 | { | |
358 | struct kprobe *kp; | |
359 | ||
360 | if (p->break_handler) { | |
361 | list_for_each_entry(kp, &old_p->list, list) { | |
362 | if (kp->break_handler) | |
363 | return -EEXIST; | |
364 | } | |
365 | list_add_tail(&p->list, &old_p->list); | |
366 | } else | |
367 | list_add(&p->list, &old_p->list); | |
368 | return 0; | |
369 | } | |
370 | ||
64f562c6 AM |
371 | /* |
372 | * Fill in the required fields of the "manager kprobe". Replace the | |
373 | * earlier kprobe in the hlist with the manager kprobe | |
374 | */ | |
375 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
376 | { | |
8b0914ea | 377 | copy_kprobe(p, ap); |
64f562c6 | 378 | ap->addr = p->addr; |
64f562c6 AM |
379 | ap->pre_handler = aggr_pre_handler; |
380 | ap->post_handler = aggr_post_handler; | |
381 | ap->fault_handler = aggr_fault_handler; | |
8b0914ea | 382 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
383 | |
384 | INIT_LIST_HEAD(&ap->list); | |
385 | list_add(&p->list, &ap->list); | |
386 | ||
387 | INIT_HLIST_NODE(&ap->hlist); | |
388 | hlist_del(&p->hlist); | |
389 | hlist_add_head(&ap->hlist, | |
390 | &kprobe_table[hash_ptr(ap->addr, KPROBE_HASH_BITS)]); | |
391 | } | |
392 | ||
393 | /* | |
394 | * This is the second or subsequent kprobe at the address - handle | |
395 | * the intricacies | |
396 | * TODO: Move kcalloc outside the spinlock | |
397 | */ | |
398 | static int register_aggr_kprobe(struct kprobe *old_p, struct kprobe *p) | |
399 | { | |
400 | int ret = 0; | |
401 | struct kprobe *ap; | |
402 | ||
8b0914ea PP |
403 | if (old_p->pre_handler == aggr_pre_handler) { |
404 | copy_kprobe(old_p, p); | |
405 | ret = add_new_kprobe(old_p, p); | |
64f562c6 AM |
406 | } else { |
407 | ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC); | |
408 | if (!ap) | |
409 | return -ENOMEM; | |
410 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
411 | copy_kprobe(ap, p); |
412 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
413 | } |
414 | return ret; | |
415 | } | |
416 | ||
417 | /* kprobe removal house-keeping routines */ | |
418 | static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags) | |
419 | { | |
7e1048b1 | 420 | arch_disarm_kprobe(p); |
64f562c6 | 421 | hlist_del(&p->hlist); |
64f562c6 AM |
422 | spin_unlock_irqrestore(&kprobe_lock, flags); |
423 | arch_remove_kprobe(p); | |
424 | } | |
425 | ||
426 | static inline void cleanup_aggr_kprobe(struct kprobe *old_p, | |
427 | struct kprobe *p, unsigned long flags) | |
428 | { | |
429 | list_del(&p->list); | |
430 | if (list_empty(&old_p->list)) { | |
431 | cleanup_kprobe(old_p, flags); | |
432 | kfree(old_p); | |
433 | } else | |
434 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
435 | } | |
436 | ||
1da177e4 LT |
437 | int register_kprobe(struct kprobe *p) |
438 | { | |
439 | int ret = 0; | |
440 | unsigned long flags = 0; | |
64f562c6 | 441 | struct kprobe *old_p; |
1da177e4 LT |
442 | |
443 | if ((ret = arch_prepare_kprobe(p)) != 0) { | |
444 | goto rm_kprobe; | |
445 | } | |
446 | spin_lock_irqsave(&kprobe_lock, flags); | |
64f562c6 | 447 | old_p = get_kprobe(p->addr); |
ea32c65c | 448 | p->nmissed = 0; |
64f562c6 AM |
449 | if (old_p) { |
450 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
451 | goto out; |
452 | } | |
1da177e4 | 453 | |
64f562c6 AM |
454 | arch_copy_kprobe(p); |
455 | INIT_HLIST_NODE(&p->hlist); | |
1da177e4 LT |
456 | hlist_add_head(&p->hlist, |
457 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); | |
458 | ||
7e1048b1 RL |
459 | arch_arm_kprobe(p); |
460 | ||
1da177e4 LT |
461 | out: |
462 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
463 | rm_kprobe: | |
464 | if (ret == -EEXIST) | |
465 | arch_remove_kprobe(p); | |
466 | return ret; | |
467 | } | |
468 | ||
469 | void unregister_kprobe(struct kprobe *p) | |
470 | { | |
471 | unsigned long flags; | |
64f562c6 AM |
472 | struct kprobe *old_p; |
473 | ||
1da177e4 | 474 | spin_lock_irqsave(&kprobe_lock, flags); |
64f562c6 AM |
475 | old_p = get_kprobe(p->addr); |
476 | if (old_p) { | |
477 | if (old_p->pre_handler == aggr_pre_handler) | |
478 | cleanup_aggr_kprobe(old_p, p, flags); | |
479 | else | |
480 | cleanup_kprobe(p, flags); | |
481 | } else | |
04dea5f9 | 482 | spin_unlock_irqrestore(&kprobe_lock, flags); |
1da177e4 LT |
483 | } |
484 | ||
485 | static struct notifier_block kprobe_exceptions_nb = { | |
486 | .notifier_call = kprobe_exceptions_notify, | |
487 | .priority = 0x7fffffff /* we need to notified first */ | |
488 | }; | |
489 | ||
490 | int register_jprobe(struct jprobe *jp) | |
491 | { | |
492 | /* Todo: Verify probepoint is a function entry point */ | |
493 | jp->kp.pre_handler = setjmp_pre_handler; | |
494 | jp->kp.break_handler = longjmp_break_handler; | |
495 | ||
496 | return register_kprobe(&jp->kp); | |
497 | } | |
498 | ||
499 | void unregister_jprobe(struct jprobe *jp) | |
500 | { | |
501 | unregister_kprobe(&jp->kp); | |
502 | } | |
503 | ||
b94cce92 HN |
504 | #ifdef ARCH_SUPPORTS_KRETPROBES |
505 | ||
506 | int register_kretprobe(struct kretprobe *rp) | |
507 | { | |
508 | int ret = 0; | |
509 | struct kretprobe_instance *inst; | |
510 | int i; | |
511 | ||
512 | rp->kp.pre_handler = pre_handler_kretprobe; | |
513 | ||
514 | /* Pre-allocate memory for max kretprobe instances */ | |
515 | if (rp->maxactive <= 0) { | |
516 | #ifdef CONFIG_PREEMPT | |
517 | rp->maxactive = max(10, 2 * NR_CPUS); | |
518 | #else | |
519 | rp->maxactive = NR_CPUS; | |
520 | #endif | |
521 | } | |
522 | INIT_HLIST_HEAD(&rp->used_instances); | |
523 | INIT_HLIST_HEAD(&rp->free_instances); | |
524 | for (i = 0; i < rp->maxactive; i++) { | |
525 | inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL); | |
526 | if (inst == NULL) { | |
527 | free_rp_inst(rp); | |
528 | return -ENOMEM; | |
529 | } | |
530 | INIT_HLIST_NODE(&inst->uflist); | |
531 | hlist_add_head(&inst->uflist, &rp->free_instances); | |
532 | } | |
533 | ||
534 | rp->nmissed = 0; | |
535 | /* Establish function entry probe point */ | |
536 | if ((ret = register_kprobe(&rp->kp)) != 0) | |
537 | free_rp_inst(rp); | |
538 | return ret; | |
539 | } | |
540 | ||
541 | #else /* ARCH_SUPPORTS_KRETPROBES */ | |
542 | ||
543 | int register_kretprobe(struct kretprobe *rp) | |
544 | { | |
545 | return -ENOSYS; | |
546 | } | |
547 | ||
548 | #endif /* ARCH_SUPPORTS_KRETPROBES */ | |
549 | ||
550 | void unregister_kretprobe(struct kretprobe *rp) | |
551 | { | |
552 | unsigned long flags; | |
553 | struct kretprobe_instance *ri; | |
554 | ||
555 | unregister_kprobe(&rp->kp); | |
556 | /* No race here */ | |
557 | spin_lock_irqsave(&kprobe_lock, flags); | |
558 | free_rp_inst(rp); | |
559 | while ((ri = get_used_rp_inst(rp)) != NULL) { | |
560 | ri->rp = NULL; | |
561 | hlist_del(&ri->uflist); | |
562 | } | |
563 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
564 | } | |
565 | ||
1da177e4 LT |
566 | static int __init init_kprobes(void) |
567 | { | |
568 | int i, err = 0; | |
569 | ||
570 | /* FIXME allocate the probe table, currently defined statically */ | |
571 | /* initialize all list heads */ | |
b94cce92 | 572 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 573 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 HN |
574 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
575 | } | |
1da177e4 | 576 | |
6772926b | 577 | err = arch_init_kprobes(); |
802eae7c RL |
578 | if (!err) |
579 | err = register_die_notifier(&kprobe_exceptions_nb); | |
580 | ||
1da177e4 LT |
581 | return err; |
582 | } | |
583 | ||
584 | __initcall(init_kprobes); | |
585 | ||
586 | EXPORT_SYMBOL_GPL(register_kprobe); | |
587 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
588 | EXPORT_SYMBOL_GPL(register_jprobe); | |
589 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
590 | EXPORT_SYMBOL_GPL(jprobe_return); | |
b94cce92 HN |
591 | EXPORT_SYMBOL_GPL(register_kretprobe); |
592 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
593 |