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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Kernel Probes (KProbes) | |
1da177e4 LT |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | * | |
18 | * Copyright (C) IBM Corporation, 2002, 2004 | |
19 | * | |
20 | * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel | |
21 | * Probes initial implementation ( includes contributions from | |
22 | * Rusty Russell). | |
23 | * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes | |
24 | * interface to access function arguments. | |
25 | * 2004-Nov Ananth N Mavinakayanahalli <ananth@in.ibm.com> kprobes port | |
26 | * for PPC64 | |
27 | */ | |
28 | ||
1da177e4 LT |
29 | #include <linux/kprobes.h> |
30 | #include <linux/ptrace.h> | |
1da177e4 | 31 | #include <linux/preempt.h> |
50e21f2b | 32 | #include <linux/module.h> |
7e1048b1 | 33 | #include <asm/cacheflush.h> |
1da177e4 LT |
34 | #include <asm/kdebug.h> |
35 | #include <asm/sstep.h> | |
50e21f2b | 36 | #include <asm/uaccess.h> |
1da177e4 | 37 | |
0dc036c9 AM |
38 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
39 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); | |
1da177e4 | 40 | |
bb144a85 | 41 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
1da177e4 | 42 | { |
63224d1e | 43 | int ret = 0; |
1da177e4 LT |
44 | kprobe_opcode_t insn = *p->addr; |
45 | ||
63224d1e AM |
46 | if ((unsigned long)p->addr & 0x03) { |
47 | printk("Attempt to register kprobe at an unaligned address\n"); | |
48 | ret = -EINVAL; | |
49 | } else if (IS_MTMSRD(insn) || IS_RFID(insn)) { | |
50 | printk("Cannot register a kprobe on rfid or mtmsrd\n"); | |
51 | ret = -EINVAL; | |
52 | } | |
9ec4b1f3 AM |
53 | |
54 | /* insn must be on a special executable page on ppc64 */ | |
55 | if (!ret) { | |
2d8ab6ad | 56 | p->ainsn.insn = get_insn_slot(); |
9ec4b1f3 AM |
57 | if (!p->ainsn.insn) |
58 | ret = -ENOMEM; | |
59 | } | |
1da177e4 | 60 | |
49a2a1b8 AK |
61 | if (!ret) { |
62 | memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); | |
63 | p->opcode = *p->addr; | |
83db3dde AM |
64 | flush_icache_range((unsigned long)p->ainsn.insn, |
65 | (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); | |
49a2a1b8 AK |
66 | } |
67 | ||
68 | return ret; | |
1da177e4 LT |
69 | } |
70 | ||
bb144a85 | 71 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
1da177e4 | 72 | { |
7e1048b1 RL |
73 | *p->addr = BREAKPOINT_INSTRUCTION; |
74 | flush_icache_range((unsigned long) p->addr, | |
75 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
1da177e4 LT |
76 | } |
77 | ||
bb144a85 | 78 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
1da177e4 LT |
79 | { |
80 | *p->addr = p->opcode; | |
7e1048b1 RL |
81 | flush_icache_range((unsigned long) p->addr, |
82 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
83 | } | |
84 | ||
0498b635 | 85 | void __kprobes arch_remove_kprobe(struct kprobe *p) |
7e1048b1 | 86 | { |
7a7d1cf9 | 87 | mutex_lock(&kprobe_mutex); |
2d8ab6ad | 88 | free_insn_slot(p->ainsn.insn); |
7a7d1cf9 | 89 | mutex_unlock(&kprobe_mutex); |
1da177e4 LT |
90 | } |
91 | ||
46dbe2f4 | 92 | static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
93 | { |
94 | regs->msr |= MSR_SE; | |
9ec4b1f3 | 95 | |
0ccde0a2 AM |
96 | /* |
97 | * On powerpc we should single step on the original | |
98 | * instruction even if the probed insn is a trap | |
99 | * variant as values in regs could play a part in | |
100 | * if the trap is taken or not | |
101 | */ | |
102 | regs->nip = (unsigned long)p->ainsn.insn; | |
1da177e4 LT |
103 | } |
104 | ||
46dbe2f4 | 105 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) |
0dc036c9 AM |
106 | { |
107 | kcb->prev_kprobe.kp = kprobe_running(); | |
108 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
109 | kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; | |
110 | } | |
111 | ||
46dbe2f4 | 112 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) |
42cc2060 | 113 | { |
0dc036c9 AM |
114 | __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; |
115 | kcb->kprobe_status = kcb->prev_kprobe.status; | |
116 | kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; | |
42cc2060 PP |
117 | } |
118 | ||
46dbe2f4 | 119 | static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, |
0dc036c9 | 120 | struct kprobe_ctlblk *kcb) |
42cc2060 | 121 | { |
0dc036c9 AM |
122 | __get_cpu_var(current_kprobe) = p; |
123 | kcb->kprobe_saved_msr = regs->msr; | |
42cc2060 PP |
124 | } |
125 | ||
991a51d8 | 126 | /* Called with kretprobe_lock held */ |
bb144a85 PP |
127 | void __kprobes arch_prepare_kretprobe(struct kretprobe *rp, |
128 | struct pt_regs *regs) | |
97f7943d RL |
129 | { |
130 | struct kretprobe_instance *ri; | |
131 | ||
132 | if ((ri = get_free_rp_inst(rp)) != NULL) { | |
133 | ri->rp = rp; | |
134 | ri->task = current; | |
135 | ri->ret_addr = (kprobe_opcode_t *)regs->link; | |
136 | ||
137 | /* Replace the return addr with trampoline addr */ | |
138 | regs->link = (unsigned long)kretprobe_trampoline; | |
139 | add_rp_inst(ri); | |
140 | } else { | |
141 | rp->nmissed++; | |
142 | } | |
143 | } | |
144 | ||
46dbe2f4 | 145 | static int __kprobes kprobe_handler(struct pt_regs *regs) |
1da177e4 LT |
146 | { |
147 | struct kprobe *p; | |
148 | int ret = 0; | |
149 | unsigned int *addr = (unsigned int *)regs->nip; | |
d217d545 AM |
150 | struct kprobe_ctlblk *kcb; |
151 | ||
152 | /* | |
153 | * We don't want to be preempted for the entire | |
154 | * duration of kprobe processing | |
155 | */ | |
156 | preempt_disable(); | |
157 | kcb = get_kprobe_ctlblk(); | |
1da177e4 LT |
158 | |
159 | /* Check we're not actually recursing */ | |
160 | if (kprobe_running()) { | |
1da177e4 LT |
161 | p = get_kprobe(addr); |
162 | if (p) { | |
deac66ae | 163 | kprobe_opcode_t insn = *p->ainsn.insn; |
0dc036c9 | 164 | if (kcb->kprobe_status == KPROBE_HIT_SS && |
deac66ae | 165 | is_trap(insn)) { |
1da177e4 | 166 | regs->msr &= ~MSR_SE; |
0dc036c9 | 167 | regs->msr |= kcb->kprobe_saved_msr; |
1da177e4 LT |
168 | goto no_kprobe; |
169 | } | |
42cc2060 PP |
170 | /* We have reentered the kprobe_handler(), since |
171 | * another probe was hit while within the handler. | |
172 | * We here save the original kprobes variables and | |
173 | * just single step on the instruction of the new probe | |
174 | * without calling any user handlers. | |
175 | */ | |
0dc036c9 AM |
176 | save_previous_kprobe(kcb); |
177 | set_current_kprobe(p, regs, kcb); | |
178 | kcb->kprobe_saved_msr = regs->msr; | |
bf8d5c52 | 179 | kprobes_inc_nmissed_count(p); |
42cc2060 | 180 | prepare_singlestep(p, regs); |
0dc036c9 | 181 | kcb->kprobe_status = KPROBE_REENTER; |
42cc2060 | 182 | return 1; |
1da177e4 | 183 | } else { |
eb3a7292 KA |
184 | if (*addr != BREAKPOINT_INSTRUCTION) { |
185 | /* If trap variant, then it belongs not to us */ | |
186 | kprobe_opcode_t cur_insn = *addr; | |
187 | if (is_trap(cur_insn)) | |
188 | goto no_kprobe; | |
189 | /* The breakpoint instruction was removed by | |
190 | * another cpu right after we hit, no further | |
191 | * handling of this interrupt is appropriate | |
192 | */ | |
193 | ret = 1; | |
194 | goto no_kprobe; | |
195 | } | |
0dc036c9 | 196 | p = __get_cpu_var(current_kprobe); |
1da177e4 LT |
197 | if (p->break_handler && p->break_handler(p, regs)) { |
198 | goto ss_probe; | |
199 | } | |
200 | } | |
1da177e4 LT |
201 | goto no_kprobe; |
202 | } | |
203 | ||
1da177e4 LT |
204 | p = get_kprobe(addr); |
205 | if (!p) { | |
1da177e4 LT |
206 | if (*addr != BREAKPOINT_INSTRUCTION) { |
207 | /* | |
208 | * PowerPC has multiple variants of the "trap" | |
209 | * instruction. If the current instruction is a | |
210 | * trap variant, it could belong to someone else | |
211 | */ | |
212 | kprobe_opcode_t cur_insn = *addr; | |
deac66ae | 213 | if (is_trap(cur_insn)) |
1da177e4 LT |
214 | goto no_kprobe; |
215 | /* | |
216 | * The breakpoint instruction was removed right | |
217 | * after we hit it. Another cpu has removed | |
218 | * either a probepoint or a debugger breakpoint | |
219 | * at this address. In either case, no further | |
220 | * handling of this interrupt is appropriate. | |
221 | */ | |
222 | ret = 1; | |
223 | } | |
224 | /* Not one of ours: let kernel handle it */ | |
225 | goto no_kprobe; | |
226 | } | |
227 | ||
0dc036c9 AM |
228 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
229 | set_current_kprobe(p, regs, kcb); | |
1da177e4 LT |
230 | if (p->pre_handler && p->pre_handler(p, regs)) |
231 | /* handler has already set things up, so skip ss setup */ | |
232 | return 1; | |
233 | ||
234 | ss_probe: | |
235 | prepare_singlestep(p, regs); | |
0dc036c9 | 236 | kcb->kprobe_status = KPROBE_HIT_SS; |
1da177e4 LT |
237 | return 1; |
238 | ||
239 | no_kprobe: | |
d217d545 | 240 | preempt_enable_no_resched(); |
1da177e4 LT |
241 | return ret; |
242 | } | |
243 | ||
97f7943d RL |
244 | /* |
245 | * Function return probe trampoline: | |
246 | * - init_kprobes() establishes a probepoint here | |
247 | * - When the probed function returns, this probe | |
248 | * causes the handlers to fire | |
249 | */ | |
250 | void kretprobe_trampoline_holder(void) | |
251 | { | |
252 | asm volatile(".global kretprobe_trampoline\n" | |
253 | "kretprobe_trampoline:\n" | |
254 | "nop\n"); | |
255 | } | |
256 | ||
257 | /* | |
258 | * Called when the probe at kretprobe trampoline is hit | |
259 | */ | |
bb144a85 | 260 | int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) |
97f7943d RL |
261 | { |
262 | struct kretprobe_instance *ri = NULL; | |
263 | struct hlist_head *head; | |
264 | struct hlist_node *node, *tmp; | |
991a51d8 | 265 | unsigned long flags, orig_ret_address = 0; |
97f7943d RL |
266 | unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; |
267 | ||
991a51d8 | 268 | spin_lock_irqsave(&kretprobe_lock, flags); |
97f7943d RL |
269 | head = kretprobe_inst_table_head(current); |
270 | ||
271 | /* | |
272 | * It is possible to have multiple instances associated with a given | |
273 | * task either because an multiple functions in the call path | |
274 | * have a return probe installed on them, and/or more then one return | |
275 | * return probe was registered for a target function. | |
276 | * | |
277 | * We can handle this because: | |
278 | * - instances are always inserted at the head of the list | |
279 | * - when multiple return probes are registered for the same | |
280 | * function, the first instance's ret_addr will point to the | |
281 | * real return address, and all the rest will point to | |
282 | * kretprobe_trampoline | |
283 | */ | |
284 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
285 | if (ri->task != current) | |
286 | /* another task is sharing our hash bucket */ | |
287 | continue; | |
288 | ||
289 | if (ri->rp && ri->rp->handler) | |
290 | ri->rp->handler(ri, regs); | |
291 | ||
292 | orig_ret_address = (unsigned long)ri->ret_addr; | |
293 | recycle_rp_inst(ri); | |
294 | ||
295 | if (orig_ret_address != trampoline_address) | |
296 | /* | |
297 | * This is the real return address. Any other | |
298 | * instances associated with this task are for | |
299 | * other calls deeper on the call stack | |
300 | */ | |
301 | break; | |
302 | } | |
303 | ||
304 | BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); | |
305 | regs->nip = orig_ret_address; | |
306 | ||
0dc036c9 | 307 | reset_current_kprobe(); |
991a51d8 | 308 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
66ff2d06 | 309 | preempt_enable_no_resched(); |
97f7943d RL |
310 | |
311 | /* | |
312 | * By returning a non-zero value, we are telling | |
d217d545 AM |
313 | * kprobe_handler() that we don't want the post_handler |
314 | * to run (and have re-enabled preemption) | |
97f7943d RL |
315 | */ |
316 | return 1; | |
317 | } | |
318 | ||
1da177e4 LT |
319 | /* |
320 | * Called after single-stepping. p->addr is the address of the | |
321 | * instruction whose first byte has been replaced by the "breakpoint" | |
322 | * instruction. To avoid the SMP problems that can occur when we | |
323 | * temporarily put back the original opcode to single-step, we | |
324 | * single-stepped a copy of the instruction. The address of this | |
325 | * copy is p->ainsn.insn. | |
326 | */ | |
bb144a85 | 327 | static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
328 | { |
329 | int ret; | |
9ec4b1f3 | 330 | unsigned int insn = *p->ainsn.insn; |
1da177e4 LT |
331 | |
332 | regs->nip = (unsigned long)p->addr; | |
9ec4b1f3 | 333 | ret = emulate_step(regs, insn); |
1da177e4 LT |
334 | if (ret == 0) |
335 | regs->nip = (unsigned long)p->addr + 4; | |
1da177e4 LT |
336 | } |
337 | ||
46dbe2f4 | 338 | static int __kprobes post_kprobe_handler(struct pt_regs *regs) |
1da177e4 | 339 | { |
0dc036c9 AM |
340 | struct kprobe *cur = kprobe_running(); |
341 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
342 | ||
343 | if (!cur) | |
1da177e4 LT |
344 | return 0; |
345 | ||
0dc036c9 AM |
346 | if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { |
347 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
348 | cur->post_handler(cur, regs, 0); | |
42cc2060 | 349 | } |
1da177e4 | 350 | |
0dc036c9 AM |
351 | resume_execution(cur, regs); |
352 | regs->msr |= kcb->kprobe_saved_msr; | |
1da177e4 | 353 | |
42cc2060 | 354 | /*Restore back the original saved kprobes variables and continue. */ |
0dc036c9 AM |
355 | if (kcb->kprobe_status == KPROBE_REENTER) { |
356 | restore_previous_kprobe(kcb); | |
42cc2060 PP |
357 | goto out; |
358 | } | |
0dc036c9 | 359 | reset_current_kprobe(); |
42cc2060 | 360 | out: |
1da177e4 LT |
361 | preempt_enable_no_resched(); |
362 | ||
363 | /* | |
364 | * if somebody else is singlestepping across a probe point, msr | |
365 | * will have SE set, in which case, continue the remaining processing | |
366 | * of do_debug, as if this is not a probe hit. | |
367 | */ | |
368 | if (regs->msr & MSR_SE) | |
369 | return 0; | |
370 | ||
371 | return 1; | |
372 | } | |
373 | ||
46dbe2f4 | 374 | static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
1da177e4 | 375 | { |
0dc036c9 AM |
376 | struct kprobe *cur = kprobe_running(); |
377 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
50e21f2b PP |
378 | const struct exception_table_entry *entry; |
379 | ||
380 | switch(kcb->kprobe_status) { | |
381 | case KPROBE_HIT_SS: | |
382 | case KPROBE_REENTER: | |
383 | /* | |
384 | * We are here because the instruction being single | |
385 | * stepped caused a page fault. We reset the current | |
386 | * kprobe and the nip points back to the probe address | |
387 | * and allow the page fault handler to continue as a | |
388 | * normal page fault. | |
389 | */ | |
390 | regs->nip = (unsigned long)cur->addr; | |
f829fd23 | 391 | regs->msr &= ~MSR_SE; |
0dc036c9 | 392 | regs->msr |= kcb->kprobe_saved_msr; |
50e21f2b PP |
393 | if (kcb->kprobe_status == KPROBE_REENTER) |
394 | restore_previous_kprobe(kcb); | |
395 | else | |
396 | reset_current_kprobe(); | |
1da177e4 | 397 | preempt_enable_no_resched(); |
50e21f2b PP |
398 | break; |
399 | case KPROBE_HIT_ACTIVE: | |
400 | case KPROBE_HIT_SSDONE: | |
401 | /* | |
402 | * We increment the nmissed count for accounting, | |
403 | * we can also use npre/npostfault count for accouting | |
404 | * these specific fault cases. | |
405 | */ | |
406 | kprobes_inc_nmissed_count(cur); | |
407 | ||
408 | /* | |
409 | * We come here because instructions in the pre/post | |
410 | * handler caused the page_fault, this could happen | |
411 | * if handler tries to access user space by | |
412 | * copy_from_user(), get_user() etc. Let the | |
413 | * user-specified handler try to fix it first. | |
414 | */ | |
415 | if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) | |
416 | return 1; | |
417 | ||
418 | /* | |
419 | * In case the user-specified fault handler returned | |
420 | * zero, try to fix up. | |
421 | */ | |
422 | if ((entry = search_exception_tables(regs->nip)) != NULL) { | |
423 | regs->nip = entry->fixup; | |
424 | return 1; | |
425 | } | |
426 | ||
427 | /* | |
428 | * fixup_exception() could not handle it, | |
429 | * Let do_page_fault() fix it. | |
430 | */ | |
431 | break; | |
432 | default: | |
433 | break; | |
1da177e4 LT |
434 | } |
435 | return 0; | |
436 | } | |
437 | ||
438 | /* | |
439 | * Wrapper routine to for handling exceptions. | |
440 | */ | |
bb144a85 PP |
441 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
442 | unsigned long val, void *data) | |
1da177e4 LT |
443 | { |
444 | struct die_args *args = (struct die_args *)data; | |
445 | int ret = NOTIFY_DONE; | |
446 | ||
2326c770 | 447 | if (args->regs && user_mode(args->regs)) |
448 | return ret; | |
449 | ||
1da177e4 | 450 | switch (val) { |
1da177e4 LT |
451 | case DIE_BPT: |
452 | if (kprobe_handler(args->regs)) | |
453 | ret = NOTIFY_STOP; | |
454 | break; | |
455 | case DIE_SSTEP: | |
456 | if (post_kprobe_handler(args->regs)) | |
457 | ret = NOTIFY_STOP; | |
458 | break; | |
1da177e4 | 459 | case DIE_PAGE_FAULT: |
d217d545 AM |
460 | /* kprobe_running() needs smp_processor_id() */ |
461 | preempt_disable(); | |
1da177e4 LT |
462 | if (kprobe_running() && |
463 | kprobe_fault_handler(args->regs, args->trapnr)) | |
464 | ret = NOTIFY_STOP; | |
d217d545 | 465 | preempt_enable(); |
1da177e4 LT |
466 | break; |
467 | default: | |
468 | break; | |
469 | } | |
1da177e4 LT |
470 | return ret; |
471 | } | |
472 | ||
bb144a85 | 473 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
474 | { |
475 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
0dc036c9 | 476 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
1da177e4 | 477 | |
0dc036c9 | 478 | memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
1da177e4 LT |
479 | |
480 | /* setup return addr to the jprobe handler routine */ | |
481 | regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry); | |
482 | regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); | |
483 | ||
484 | return 1; | |
485 | } | |
486 | ||
bb144a85 | 487 | void __kprobes jprobe_return(void) |
1da177e4 LT |
488 | { |
489 | asm volatile("trap" ::: "memory"); | |
490 | } | |
491 | ||
bb144a85 | 492 | void __kprobes jprobe_return_end(void) |
1da177e4 LT |
493 | { |
494 | }; | |
495 | ||
bb144a85 | 496 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 | 497 | { |
0dc036c9 AM |
498 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
499 | ||
1da177e4 LT |
500 | /* |
501 | * FIXME - we should ideally be validating that we got here 'cos | |
502 | * of the "trap" in jprobe_return() above, before restoring the | |
503 | * saved regs... | |
504 | */ | |
0dc036c9 | 505 | memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); |
d217d545 | 506 | preempt_enable_no_resched(); |
1da177e4 LT |
507 | return 1; |
508 | } | |
97f7943d RL |
509 | |
510 | static struct kprobe trampoline_p = { | |
511 | .addr = (kprobe_opcode_t *) &kretprobe_trampoline, | |
512 | .pre_handler = trampoline_probe_handler | |
513 | }; | |
514 | ||
6772926b | 515 | int __init arch_init_kprobes(void) |
97f7943d RL |
516 | { |
517 | return register_kprobe(&trampoline_p); | |
518 | } |