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> |
d0aaff97 | 40 | #include <asm-generic/sections.h> |
1da177e4 LT |
41 | #include <asm/cacheflush.h> |
42 | #include <asm/errno.h> | |
43 | #include <asm/kdebug.h> | |
44 | ||
45 | #define KPROBE_HASH_BITS 6 | |
46 | #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) | |
47 | ||
48 | static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; | |
b94cce92 | 49 | static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
1da177e4 LT |
50 | |
51 | unsigned int kprobe_cpu = NR_CPUS; | |
52 | static DEFINE_SPINLOCK(kprobe_lock); | |
64f562c6 | 53 | static struct kprobe *curr_kprobe; |
1da177e4 | 54 | |
9ec4b1f3 AM |
55 | /* |
56 | * kprobe->ainsn.insn points to the copy of the instruction to be | |
57 | * single-stepped. x86_64, POWER4 and above have no-exec support and | |
58 | * stepping on the instruction on a vmalloced/kmalloced/data page | |
59 | * is a recipe for disaster | |
60 | */ | |
61 | #define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))) | |
62 | ||
63 | struct kprobe_insn_page { | |
64 | struct hlist_node hlist; | |
65 | kprobe_opcode_t *insns; /* Page of instruction slots */ | |
66 | char slot_used[INSNS_PER_PAGE]; | |
67 | int nused; | |
68 | }; | |
69 | ||
70 | static struct hlist_head kprobe_insn_pages; | |
71 | ||
72 | /** | |
73 | * get_insn_slot() - Find a slot on an executable page for an instruction. | |
74 | * We allocate an executable page if there's no room on existing ones. | |
75 | */ | |
d0aaff97 | 76 | kprobe_opcode_t __kprobes *get_insn_slot(void) |
9ec4b1f3 AM |
77 | { |
78 | struct kprobe_insn_page *kip; | |
79 | struct hlist_node *pos; | |
80 | ||
81 | hlist_for_each(pos, &kprobe_insn_pages) { | |
82 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); | |
83 | if (kip->nused < INSNS_PER_PAGE) { | |
84 | int i; | |
85 | for (i = 0; i < INSNS_PER_PAGE; i++) { | |
86 | if (!kip->slot_used[i]) { | |
87 | kip->slot_used[i] = 1; | |
88 | kip->nused++; | |
89 | return kip->insns + (i * MAX_INSN_SIZE); | |
90 | } | |
91 | } | |
92 | /* Surprise! No unused slots. Fix kip->nused. */ | |
93 | kip->nused = INSNS_PER_PAGE; | |
94 | } | |
95 | } | |
96 | ||
97 | /* All out of space. Need to allocate a new page. Use slot 0.*/ | |
98 | kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL); | |
99 | if (!kip) { | |
100 | return NULL; | |
101 | } | |
102 | ||
103 | /* | |
104 | * Use module_alloc so this page is within +/- 2GB of where the | |
105 | * kernel image and loaded module images reside. This is required | |
106 | * so x86_64 can correctly handle the %rip-relative fixups. | |
107 | */ | |
108 | kip->insns = module_alloc(PAGE_SIZE); | |
109 | if (!kip->insns) { | |
110 | kfree(kip); | |
111 | return NULL; | |
112 | } | |
113 | INIT_HLIST_NODE(&kip->hlist); | |
114 | hlist_add_head(&kip->hlist, &kprobe_insn_pages); | |
115 | memset(kip->slot_used, 0, INSNS_PER_PAGE); | |
116 | kip->slot_used[0] = 1; | |
117 | kip->nused = 1; | |
118 | return kip->insns; | |
119 | } | |
120 | ||
d0aaff97 | 121 | void __kprobes free_insn_slot(kprobe_opcode_t *slot) |
9ec4b1f3 AM |
122 | { |
123 | struct kprobe_insn_page *kip; | |
124 | struct hlist_node *pos; | |
125 | ||
126 | hlist_for_each(pos, &kprobe_insn_pages) { | |
127 | kip = hlist_entry(pos, struct kprobe_insn_page, hlist); | |
128 | if (kip->insns <= slot && | |
129 | slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { | |
130 | int i = (slot - kip->insns) / MAX_INSN_SIZE; | |
131 | kip->slot_used[i] = 0; | |
132 | kip->nused--; | |
133 | if (kip->nused == 0) { | |
134 | /* | |
135 | * Page is no longer in use. Free it unless | |
136 | * it's the last one. We keep the last one | |
137 | * so as not to have to set it up again the | |
138 | * next time somebody inserts a probe. | |
139 | */ | |
140 | hlist_del(&kip->hlist); | |
141 | if (hlist_empty(&kprobe_insn_pages)) { | |
142 | INIT_HLIST_NODE(&kip->hlist); | |
143 | hlist_add_head(&kip->hlist, | |
144 | &kprobe_insn_pages); | |
145 | } else { | |
146 | module_free(NULL, kip->insns); | |
147 | kfree(kip); | |
148 | } | |
149 | } | |
150 | return; | |
151 | } | |
152 | } | |
153 | } | |
154 | ||
1da177e4 | 155 | /* Locks kprobe: irqs must be disabled */ |
d0aaff97 | 156 | void __kprobes lock_kprobes(void) |
1da177e4 | 157 | { |
deac66ae KA |
158 | unsigned long flags = 0; |
159 | ||
160 | /* Avoiding local interrupts to happen right after we take the kprobe_lock | |
161 | * and before we get a chance to update kprobe_cpu, this to prevent | |
162 | * deadlock when we have a kprobe on ISR routine and a kprobe on task | |
163 | * routine | |
164 | */ | |
165 | local_irq_save(flags); | |
166 | ||
1da177e4 LT |
167 | spin_lock(&kprobe_lock); |
168 | kprobe_cpu = smp_processor_id(); | |
deac66ae KA |
169 | |
170 | local_irq_restore(flags); | |
1da177e4 LT |
171 | } |
172 | ||
d0aaff97 | 173 | void __kprobes unlock_kprobes(void) |
1da177e4 | 174 | { |
deac66ae KA |
175 | unsigned long flags = 0; |
176 | ||
177 | /* Avoiding local interrupts to happen right after we update | |
178 | * kprobe_cpu and before we get a a chance to release kprobe_lock, | |
179 | * this to prevent deadlock when we have a kprobe on ISR routine and | |
180 | * a kprobe on task routine | |
181 | */ | |
182 | local_irq_save(flags); | |
183 | ||
1da177e4 LT |
184 | kprobe_cpu = NR_CPUS; |
185 | spin_unlock(&kprobe_lock); | |
deac66ae KA |
186 | |
187 | local_irq_restore(flags); | |
1da177e4 LT |
188 | } |
189 | ||
190 | /* You have to be holding the kprobe_lock */ | |
d0aaff97 | 191 | struct kprobe __kprobes *get_kprobe(void *addr) |
1da177e4 LT |
192 | { |
193 | struct hlist_head *head; | |
194 | struct hlist_node *node; | |
195 | ||
196 | head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; | |
197 | hlist_for_each(node, head) { | |
198 | struct kprobe *p = hlist_entry(node, struct kprobe, hlist); | |
199 | if (p->addr == addr) | |
200 | return p; | |
201 | } | |
202 | return NULL; | |
203 | } | |
204 | ||
64f562c6 AM |
205 | /* |
206 | * Aggregate handlers for multiple kprobes support - these handlers | |
207 | * take care of invoking the individual kprobe handlers on p->list | |
208 | */ | |
d0aaff97 | 209 | static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6 AM |
210 | { |
211 | struct kprobe *kp; | |
212 | ||
213 | list_for_each_entry(kp, &p->list, list) { | |
214 | if (kp->pre_handler) { | |
215 | curr_kprobe = kp; | |
8b0914ea PP |
216 | if (kp->pre_handler(kp, regs)) |
217 | return 1; | |
64f562c6 | 218 | } |
8b0914ea | 219 | curr_kprobe = NULL; |
64f562c6 AM |
220 | } |
221 | return 0; | |
222 | } | |
223 | ||
d0aaff97 PP |
224 | static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs, |
225 | unsigned long flags) | |
64f562c6 AM |
226 | { |
227 | struct kprobe *kp; | |
228 | ||
229 | list_for_each_entry(kp, &p->list, list) { | |
230 | if (kp->post_handler) { | |
231 | curr_kprobe = kp; | |
232 | kp->post_handler(kp, regs, flags); | |
233 | curr_kprobe = NULL; | |
234 | } | |
235 | } | |
236 | return; | |
237 | } | |
238 | ||
d0aaff97 PP |
239 | static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, |
240 | int trapnr) | |
64f562c6 AM |
241 | { |
242 | /* | |
243 | * if we faulted "during" the execution of a user specified | |
244 | * probe handler, invoke just that probe's fault handler | |
245 | */ | |
246 | if (curr_kprobe && curr_kprobe->fault_handler) { | |
247 | if (curr_kprobe->fault_handler(curr_kprobe, regs, trapnr)) | |
248 | return 1; | |
249 | } | |
250 | return 0; | |
251 | } | |
252 | ||
d0aaff97 | 253 | static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs) |
8b0914ea PP |
254 | { |
255 | struct kprobe *kp = curr_kprobe; | |
256 | if (curr_kprobe && kp->break_handler) { | |
257 | if (kp->break_handler(kp, regs)) { | |
258 | curr_kprobe = NULL; | |
259 | return 1; | |
260 | } | |
261 | } | |
262 | curr_kprobe = NULL; | |
263 | return 0; | |
264 | } | |
265 | ||
d0aaff97 | 266 | struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp) |
b94cce92 HN |
267 | { |
268 | struct hlist_node *node; | |
269 | struct kretprobe_instance *ri; | |
270 | hlist_for_each_entry(ri, node, &rp->free_instances, uflist) | |
271 | return ri; | |
272 | return NULL; | |
273 | } | |
274 | ||
d0aaff97 PP |
275 | static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe |
276 | *rp) | |
b94cce92 HN |
277 | { |
278 | struct hlist_node *node; | |
279 | struct kretprobe_instance *ri; | |
280 | hlist_for_each_entry(ri, node, &rp->used_instances, uflist) | |
281 | return ri; | |
282 | return NULL; | |
283 | } | |
284 | ||
d0aaff97 | 285 | void __kprobes add_rp_inst(struct kretprobe_instance *ri) |
b94cce92 | 286 | { |
b94cce92 HN |
287 | /* |
288 | * Remove rp inst off the free list - | |
289 | * Add it back when probed function returns | |
290 | */ | |
291 | hlist_del(&ri->uflist); | |
802eae7c | 292 | |
b94cce92 HN |
293 | /* Add rp inst onto table */ |
294 | INIT_HLIST_NODE(&ri->hlist); | |
295 | hlist_add_head(&ri->hlist, | |
802eae7c | 296 | &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]); |
b94cce92 HN |
297 | |
298 | /* Also add this rp inst to the used list. */ | |
299 | INIT_HLIST_NODE(&ri->uflist); | |
300 | hlist_add_head(&ri->uflist, &ri->rp->used_instances); | |
301 | } | |
302 | ||
d0aaff97 | 303 | void __kprobes recycle_rp_inst(struct kretprobe_instance *ri) |
b94cce92 HN |
304 | { |
305 | /* remove rp inst off the rprobe_inst_table */ | |
306 | hlist_del(&ri->hlist); | |
307 | if (ri->rp) { | |
308 | /* remove rp inst off the used list */ | |
309 | hlist_del(&ri->uflist); | |
310 | /* put rp inst back onto the free list */ | |
311 | INIT_HLIST_NODE(&ri->uflist); | |
312 | hlist_add_head(&ri->uflist, &ri->rp->free_instances); | |
313 | } else | |
314 | /* Unregistering */ | |
315 | kfree(ri); | |
316 | } | |
317 | ||
d0aaff97 | 318 | struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) |
b94cce92 HN |
319 | { |
320 | return &kretprobe_inst_table[hash_ptr(tsk, KPROBE_HASH_BITS)]; | |
321 | } | |
322 | ||
b94cce92 | 323 | /* |
802eae7c RL |
324 | * This function is called from exit_thread or flush_thread when task tk's |
325 | * stack is being recycled so that we can recycle any function-return probe | |
326 | * instances associated with this task. These left over instances represent | |
327 | * probed functions that have been called but will never return. | |
b94cce92 | 328 | */ |
d0aaff97 | 329 | void __kprobes kprobe_flush_task(struct task_struct *tk) |
b94cce92 | 330 | { |
802eae7c RL |
331 | struct kretprobe_instance *ri; |
332 | struct hlist_head *head; | |
333 | struct hlist_node *node, *tmp; | |
0aa55e4d | 334 | unsigned long flags = 0; |
802eae7c | 335 | |
0aa55e4d | 336 | spin_lock_irqsave(&kprobe_lock, flags); |
802eae7c RL |
337 | head = kretprobe_inst_table_head(current); |
338 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
339 | if (ri->task == tk) | |
340 | recycle_rp_inst(ri); | |
341 | } | |
0aa55e4d | 342 | spin_unlock_irqrestore(&kprobe_lock, flags); |
b94cce92 HN |
343 | } |
344 | ||
345 | /* | |
346 | * This kprobe pre_handler is registered with every kretprobe. When probe | |
347 | * hits it will set up the return probe. | |
348 | */ | |
d0aaff97 PP |
349 | static int __kprobes pre_handler_kretprobe(struct kprobe *p, |
350 | struct pt_regs *regs) | |
b94cce92 HN |
351 | { |
352 | struct kretprobe *rp = container_of(p, struct kretprobe, kp); | |
353 | ||
354 | /*TODO: consider to only swap the RA after the last pre_handler fired */ | |
355 | arch_prepare_kretprobe(rp, regs); | |
356 | return 0; | |
357 | } | |
358 | ||
359 | static inline void free_rp_inst(struct kretprobe *rp) | |
360 | { | |
361 | struct kretprobe_instance *ri; | |
362 | while ((ri = get_free_rp_inst(rp)) != NULL) { | |
363 | hlist_del(&ri->uflist); | |
364 | kfree(ri); | |
365 | } | |
366 | } | |
367 | ||
8b0914ea PP |
368 | /* |
369 | * Keep all fields in the kprobe consistent | |
370 | */ | |
371 | static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) | |
372 | { | |
373 | memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); | |
374 | memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); | |
375 | } | |
376 | ||
377 | /* | |
378 | * Add the new probe to old_p->list. Fail if this is the | |
379 | * second jprobe at the address - two jprobes can't coexist | |
380 | */ | |
d0aaff97 | 381 | static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p) |
8b0914ea PP |
382 | { |
383 | struct kprobe *kp; | |
384 | ||
385 | if (p->break_handler) { | |
386 | list_for_each_entry(kp, &old_p->list, list) { | |
387 | if (kp->break_handler) | |
388 | return -EEXIST; | |
389 | } | |
390 | list_add_tail(&p->list, &old_p->list); | |
391 | } else | |
392 | list_add(&p->list, &old_p->list); | |
393 | return 0; | |
394 | } | |
395 | ||
64f562c6 AM |
396 | /* |
397 | * Fill in the required fields of the "manager kprobe". Replace the | |
398 | * earlier kprobe in the hlist with the manager kprobe | |
399 | */ | |
400 | static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p) | |
401 | { | |
8b0914ea | 402 | copy_kprobe(p, ap); |
64f562c6 | 403 | ap->addr = p->addr; |
64f562c6 AM |
404 | ap->pre_handler = aggr_pre_handler; |
405 | ap->post_handler = aggr_post_handler; | |
406 | ap->fault_handler = aggr_fault_handler; | |
8b0914ea | 407 | ap->break_handler = aggr_break_handler; |
64f562c6 AM |
408 | |
409 | INIT_LIST_HEAD(&ap->list); | |
410 | list_add(&p->list, &ap->list); | |
411 | ||
412 | INIT_HLIST_NODE(&ap->hlist); | |
413 | hlist_del(&p->hlist); | |
414 | hlist_add_head(&ap->hlist, | |
415 | &kprobe_table[hash_ptr(ap->addr, KPROBE_HASH_BITS)]); | |
416 | } | |
417 | ||
418 | /* | |
419 | * This is the second or subsequent kprobe at the address - handle | |
420 | * the intricacies | |
421 | * TODO: Move kcalloc outside the spinlock | |
422 | */ | |
d0aaff97 PP |
423 | static int __kprobes register_aggr_kprobe(struct kprobe *old_p, |
424 | struct kprobe *p) | |
64f562c6 AM |
425 | { |
426 | int ret = 0; | |
427 | struct kprobe *ap; | |
428 | ||
8b0914ea PP |
429 | if (old_p->pre_handler == aggr_pre_handler) { |
430 | copy_kprobe(old_p, p); | |
431 | ret = add_new_kprobe(old_p, p); | |
64f562c6 AM |
432 | } else { |
433 | ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC); | |
434 | if (!ap) | |
435 | return -ENOMEM; | |
436 | add_aggr_kprobe(ap, old_p); | |
8b0914ea PP |
437 | copy_kprobe(ap, p); |
438 | ret = add_new_kprobe(ap, p); | |
64f562c6 AM |
439 | } |
440 | return ret; | |
441 | } | |
442 | ||
443 | /* kprobe removal house-keeping routines */ | |
444 | static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags) | |
445 | { | |
7e1048b1 | 446 | arch_disarm_kprobe(p); |
64f562c6 | 447 | hlist_del(&p->hlist); |
64f562c6 AM |
448 | spin_unlock_irqrestore(&kprobe_lock, flags); |
449 | arch_remove_kprobe(p); | |
450 | } | |
451 | ||
452 | static inline void cleanup_aggr_kprobe(struct kprobe *old_p, | |
453 | struct kprobe *p, unsigned long flags) | |
454 | { | |
455 | list_del(&p->list); | |
456 | if (list_empty(&old_p->list)) { | |
457 | cleanup_kprobe(old_p, flags); | |
458 | kfree(old_p); | |
459 | } else | |
460 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
461 | } | |
462 | ||
d0aaff97 PP |
463 | static int __kprobes in_kprobes_functions(unsigned long addr) |
464 | { | |
465 | if (addr >= (unsigned long)__kprobes_text_start | |
466 | && addr < (unsigned long)__kprobes_text_end) | |
467 | return -EINVAL; | |
468 | return 0; | |
469 | } | |
470 | ||
471 | int __kprobes register_kprobe(struct kprobe *p) | |
1da177e4 LT |
472 | { |
473 | int ret = 0; | |
474 | unsigned long flags = 0; | |
64f562c6 | 475 | struct kprobe *old_p; |
1da177e4 | 476 | |
d0aaff97 PP |
477 | if ((ret = in_kprobes_functions((unsigned long) p->addr)) != 0) |
478 | return ret; | |
479 | if ((ret = arch_prepare_kprobe(p)) != 0) | |
1da177e4 | 480 | goto rm_kprobe; |
d0aaff97 | 481 | |
1da177e4 | 482 | spin_lock_irqsave(&kprobe_lock, flags); |
64f562c6 | 483 | old_p = get_kprobe(p->addr); |
ea32c65c | 484 | p->nmissed = 0; |
64f562c6 AM |
485 | if (old_p) { |
486 | ret = register_aggr_kprobe(old_p, p); | |
1da177e4 LT |
487 | goto out; |
488 | } | |
1da177e4 | 489 | |
64f562c6 AM |
490 | arch_copy_kprobe(p); |
491 | INIT_HLIST_NODE(&p->hlist); | |
1da177e4 LT |
492 | hlist_add_head(&p->hlist, |
493 | &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); | |
494 | ||
7e1048b1 RL |
495 | arch_arm_kprobe(p); |
496 | ||
1da177e4 LT |
497 | out: |
498 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
499 | rm_kprobe: | |
500 | if (ret == -EEXIST) | |
501 | arch_remove_kprobe(p); | |
502 | return ret; | |
503 | } | |
504 | ||
d0aaff97 | 505 | void __kprobes unregister_kprobe(struct kprobe *p) |
1da177e4 LT |
506 | { |
507 | unsigned long flags; | |
64f562c6 AM |
508 | struct kprobe *old_p; |
509 | ||
1da177e4 | 510 | spin_lock_irqsave(&kprobe_lock, flags); |
64f562c6 AM |
511 | old_p = get_kprobe(p->addr); |
512 | if (old_p) { | |
513 | if (old_p->pre_handler == aggr_pre_handler) | |
514 | cleanup_aggr_kprobe(old_p, p, flags); | |
515 | else | |
516 | cleanup_kprobe(p, flags); | |
517 | } else | |
04dea5f9 | 518 | spin_unlock_irqrestore(&kprobe_lock, flags); |
1da177e4 LT |
519 | } |
520 | ||
521 | static struct notifier_block kprobe_exceptions_nb = { | |
522 | .notifier_call = kprobe_exceptions_notify, | |
523 | .priority = 0x7fffffff /* we need to notified first */ | |
524 | }; | |
525 | ||
d0aaff97 | 526 | int __kprobes register_jprobe(struct jprobe *jp) |
1da177e4 LT |
527 | { |
528 | /* Todo: Verify probepoint is a function entry point */ | |
529 | jp->kp.pre_handler = setjmp_pre_handler; | |
530 | jp->kp.break_handler = longjmp_break_handler; | |
531 | ||
532 | return register_kprobe(&jp->kp); | |
533 | } | |
534 | ||
d0aaff97 | 535 | void __kprobes unregister_jprobe(struct jprobe *jp) |
1da177e4 LT |
536 | { |
537 | unregister_kprobe(&jp->kp); | |
538 | } | |
539 | ||
b94cce92 HN |
540 | #ifdef ARCH_SUPPORTS_KRETPROBES |
541 | ||
d0aaff97 | 542 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
543 | { |
544 | int ret = 0; | |
545 | struct kretprobe_instance *inst; | |
546 | int i; | |
547 | ||
548 | rp->kp.pre_handler = pre_handler_kretprobe; | |
549 | ||
550 | /* Pre-allocate memory for max kretprobe instances */ | |
551 | if (rp->maxactive <= 0) { | |
552 | #ifdef CONFIG_PREEMPT | |
553 | rp->maxactive = max(10, 2 * NR_CPUS); | |
554 | #else | |
555 | rp->maxactive = NR_CPUS; | |
556 | #endif | |
557 | } | |
558 | INIT_HLIST_HEAD(&rp->used_instances); | |
559 | INIT_HLIST_HEAD(&rp->free_instances); | |
560 | for (i = 0; i < rp->maxactive; i++) { | |
561 | inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL); | |
562 | if (inst == NULL) { | |
563 | free_rp_inst(rp); | |
564 | return -ENOMEM; | |
565 | } | |
566 | INIT_HLIST_NODE(&inst->uflist); | |
567 | hlist_add_head(&inst->uflist, &rp->free_instances); | |
568 | } | |
569 | ||
570 | rp->nmissed = 0; | |
571 | /* Establish function entry probe point */ | |
572 | if ((ret = register_kprobe(&rp->kp)) != 0) | |
573 | free_rp_inst(rp); | |
574 | return ret; | |
575 | } | |
576 | ||
577 | #else /* ARCH_SUPPORTS_KRETPROBES */ | |
578 | ||
d0aaff97 | 579 | int __kprobes register_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
580 | { |
581 | return -ENOSYS; | |
582 | } | |
583 | ||
584 | #endif /* ARCH_SUPPORTS_KRETPROBES */ | |
585 | ||
d0aaff97 | 586 | void __kprobes unregister_kretprobe(struct kretprobe *rp) |
b94cce92 HN |
587 | { |
588 | unsigned long flags; | |
589 | struct kretprobe_instance *ri; | |
590 | ||
591 | unregister_kprobe(&rp->kp); | |
592 | /* No race here */ | |
593 | spin_lock_irqsave(&kprobe_lock, flags); | |
594 | free_rp_inst(rp); | |
595 | while ((ri = get_used_rp_inst(rp)) != NULL) { | |
596 | ri->rp = NULL; | |
597 | hlist_del(&ri->uflist); | |
598 | } | |
599 | spin_unlock_irqrestore(&kprobe_lock, flags); | |
600 | } | |
601 | ||
1da177e4 LT |
602 | static int __init init_kprobes(void) |
603 | { | |
604 | int i, err = 0; | |
605 | ||
606 | /* FIXME allocate the probe table, currently defined statically */ | |
607 | /* initialize all list heads */ | |
b94cce92 | 608 | for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4 | 609 | INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce92 HN |
610 | INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
611 | } | |
1da177e4 | 612 | |
6772926b | 613 | err = arch_init_kprobes(); |
802eae7c RL |
614 | if (!err) |
615 | err = register_die_notifier(&kprobe_exceptions_nb); | |
616 | ||
1da177e4 LT |
617 | return err; |
618 | } | |
619 | ||
620 | __initcall(init_kprobes); | |
621 | ||
622 | EXPORT_SYMBOL_GPL(register_kprobe); | |
623 | EXPORT_SYMBOL_GPL(unregister_kprobe); | |
624 | EXPORT_SYMBOL_GPL(register_jprobe); | |
625 | EXPORT_SYMBOL_GPL(unregister_jprobe); | |
626 | EXPORT_SYMBOL_GPL(jprobe_return); | |
b94cce92 HN |
627 | EXPORT_SYMBOL_GPL(register_kretprobe); |
628 | EXPORT_SYMBOL_GPL(unregister_kretprobe); | |
629 |