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> |
8a39b05f | 32 | #include <linux/extable.h> |
1eeb66a1 | 33 | #include <linux/kdebug.h> |
5a0e3ad6 | 34 | #include <linux/slab.h> |
2f0143c9 | 35 | #include <asm/code-patching.h> |
7e1048b1 | 36 | #include <asm/cacheflush.h> |
1da177e4 | 37 | #include <asm/sstep.h> |
7c0f6ba6 | 38 | #include <linux/uaccess.h> |
f8279621 | 39 | |
0dc036c9 AM |
40 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
41 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); | |
1da177e4 | 42 | |
f438d914 MH |
43 | struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; |
44 | ||
bb144a85 | 45 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
1da177e4 | 46 | { |
63224d1e | 47 | int ret = 0; |
1da177e4 LT |
48 | kprobe_opcode_t insn = *p->addr; |
49 | ||
63224d1e AM |
50 | if ((unsigned long)p->addr & 0x03) { |
51 | printk("Attempt to register kprobe at an unaligned address\n"); | |
52 | ret = -EINVAL; | |
82090035 KG |
53 | } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) { |
54 | printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n"); | |
63224d1e AM |
55 | ret = -EINVAL; |
56 | } | |
9ec4b1f3 | 57 | |
f8279621 KG |
58 | /* insn must be on a special executable page on ppc64. This is |
59 | * not explicitly required on ppc32 (right now), but it doesn't hurt */ | |
9ec4b1f3 | 60 | if (!ret) { |
2d8ab6ad | 61 | p->ainsn.insn = get_insn_slot(); |
9ec4b1f3 AM |
62 | if (!p->ainsn.insn) |
63 | ret = -ENOMEM; | |
64 | } | |
1da177e4 | 65 | |
49a2a1b8 | 66 | if (!ret) { |
e6349a95 AM |
67 | memcpy(p->ainsn.insn, p->addr, |
68 | MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); | |
49a2a1b8 | 69 | p->opcode = *p->addr; |
83db3dde AM |
70 | flush_icache_range((unsigned long)p->ainsn.insn, |
71 | (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); | |
49a2a1b8 AK |
72 | } |
73 | ||
e6349a95 | 74 | p->ainsn.boostable = 0; |
49a2a1b8 | 75 | return ret; |
1da177e4 LT |
76 | } |
77 | ||
bb144a85 | 78 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
1da177e4 | 79 | { |
7e1048b1 RL |
80 | *p->addr = BREAKPOINT_INSTRUCTION; |
81 | flush_icache_range((unsigned long) p->addr, | |
82 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
1da177e4 LT |
83 | } |
84 | ||
bb144a85 | 85 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
1da177e4 LT |
86 | { |
87 | *p->addr = p->opcode; | |
7e1048b1 RL |
88 | flush_icache_range((unsigned long) p->addr, |
89 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
90 | } | |
91 | ||
0498b635 | 92 | void __kprobes arch_remove_kprobe(struct kprobe *p) |
7e1048b1 | 93 | { |
12941560 MH |
94 | if (p->ainsn.insn) { |
95 | free_insn_slot(p->ainsn.insn, 0); | |
96 | p->ainsn.insn = NULL; | |
97 | } | |
1da177e4 LT |
98 | } |
99 | ||
46dbe2f4 | 100 | static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
1da177e4 | 101 | { |
35fd219a | 102 | enable_single_step(regs); |
9ec4b1f3 | 103 | |
0ccde0a2 AM |
104 | /* |
105 | * On powerpc we should single step on the original | |
106 | * instruction even if the probed insn is a trap | |
107 | * variant as values in regs could play a part in | |
108 | * if the trap is taken or not | |
109 | */ | |
110 | regs->nip = (unsigned long)p->ainsn.insn; | |
1da177e4 LT |
111 | } |
112 | ||
46dbe2f4 | 113 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) |
0dc036c9 AM |
114 | { |
115 | kcb->prev_kprobe.kp = kprobe_running(); | |
116 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
117 | kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; | |
118 | } | |
119 | ||
46dbe2f4 | 120 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) |
42cc2060 | 121 | { |
69111bac | 122 | __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); |
0dc036c9 AM |
123 | kcb->kprobe_status = kcb->prev_kprobe.status; |
124 | kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; | |
42cc2060 PP |
125 | } |
126 | ||
46dbe2f4 | 127 | static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, |
0dc036c9 | 128 | struct kprobe_ctlblk *kcb) |
42cc2060 | 129 | { |
69111bac | 130 | __this_cpu_write(current_kprobe, p); |
0dc036c9 | 131 | kcb->kprobe_saved_msr = regs->msr; |
42cc2060 PP |
132 | } |
133 | ||
4c4308cb | 134 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, |
bb144a85 | 135 | struct pt_regs *regs) |
97f7943d | 136 | { |
4c4308cb CH |
137 | ri->ret_addr = (kprobe_opcode_t *)regs->link; |
138 | ||
139 | /* Replace the return addr with trampoline addr */ | |
140 | regs->link = (unsigned long)kretprobe_trampoline; | |
97f7943d RL |
141 | } |
142 | ||
6cc89bad | 143 | int __kprobes kprobe_handler(struct pt_regs *regs) |
1da177e4 LT |
144 | { |
145 | struct kprobe *p; | |
146 | int ret = 0; | |
147 | unsigned int *addr = (unsigned int *)regs->nip; | |
d217d545 AM |
148 | struct kprobe_ctlblk *kcb; |
149 | ||
6cc89bad NR |
150 | if (user_mode(regs)) |
151 | return 0; | |
152 | ||
d217d545 AM |
153 | /* |
154 | * We don't want to be preempted for the entire | |
155 | * duration of kprobe processing | |
156 | */ | |
157 | preempt_disable(); | |
158 | kcb = get_kprobe_ctlblk(); | |
1da177e4 LT |
159 | |
160 | /* Check we're not actually recursing */ | |
161 | if (kprobe_running()) { | |
1da177e4 LT |
162 | p = get_kprobe(addr); |
163 | if (p) { | |
deac66ae | 164 | kprobe_opcode_t insn = *p->ainsn.insn; |
0dc036c9 | 165 | if (kcb->kprobe_status == KPROBE_HIT_SS && |
deac66ae | 166 | is_trap(insn)) { |
f8279621 KG |
167 | /* Turn off 'trace' bits */ |
168 | regs->msr &= ~MSR_SINGLESTEP; | |
0dc036c9 | 169 | regs->msr |= kcb->kprobe_saved_msr; |
1da177e4 LT |
170 | goto no_kprobe; |
171 | } | |
42cc2060 PP |
172 | /* We have reentered the kprobe_handler(), since |
173 | * another probe was hit while within the handler. | |
174 | * We here save the original kprobes variables and | |
175 | * just single step on the instruction of the new probe | |
176 | * without calling any user handlers. | |
177 | */ | |
0dc036c9 AM |
178 | save_previous_kprobe(kcb); |
179 | set_current_kprobe(p, regs, kcb); | |
180 | kcb->kprobe_saved_msr = regs->msr; | |
bf8d5c52 | 181 | kprobes_inc_nmissed_count(p); |
42cc2060 | 182 | prepare_singlestep(p, regs); |
0dc036c9 | 183 | kcb->kprobe_status = KPROBE_REENTER; |
42cc2060 | 184 | return 1; |
1da177e4 | 185 | } else { |
eb3a7292 KA |
186 | if (*addr != BREAKPOINT_INSTRUCTION) { |
187 | /* If trap variant, then it belongs not to us */ | |
188 | kprobe_opcode_t cur_insn = *addr; | |
189 | if (is_trap(cur_insn)) | |
190 | goto no_kprobe; | |
191 | /* The breakpoint instruction was removed by | |
192 | * another cpu right after we hit, no further | |
193 | * handling of this interrupt is appropriate | |
194 | */ | |
195 | ret = 1; | |
196 | goto no_kprobe; | |
197 | } | |
69111bac | 198 | p = __this_cpu_read(current_kprobe); |
1da177e4 LT |
199 | if (p->break_handler && p->break_handler(p, regs)) { |
200 | goto ss_probe; | |
201 | } | |
202 | } | |
1da177e4 LT |
203 | goto no_kprobe; |
204 | } | |
205 | ||
1da177e4 LT |
206 | p = get_kprobe(addr); |
207 | if (!p) { | |
1da177e4 LT |
208 | if (*addr != BREAKPOINT_INSTRUCTION) { |
209 | /* | |
210 | * PowerPC has multiple variants of the "trap" | |
211 | * instruction. If the current instruction is a | |
212 | * trap variant, it could belong to someone else | |
213 | */ | |
214 | kprobe_opcode_t cur_insn = *addr; | |
deac66ae | 215 | if (is_trap(cur_insn)) |
1da177e4 LT |
216 | goto no_kprobe; |
217 | /* | |
218 | * The breakpoint instruction was removed right | |
219 | * after we hit it. Another cpu has removed | |
220 | * either a probepoint or a debugger breakpoint | |
221 | * at this address. In either case, no further | |
222 | * handling of this interrupt is appropriate. | |
223 | */ | |
224 | ret = 1; | |
225 | } | |
226 | /* Not one of ours: let kernel handle it */ | |
227 | goto no_kprobe; | |
228 | } | |
229 | ||
0dc036c9 AM |
230 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
231 | set_current_kprobe(p, regs, kcb); | |
1da177e4 LT |
232 | if (p->pre_handler && p->pre_handler(p, regs)) |
233 | /* handler has already set things up, so skip ss setup */ | |
234 | return 1; | |
235 | ||
236 | ss_probe: | |
e6349a95 AM |
237 | if (p->ainsn.boostable >= 0) { |
238 | unsigned int insn = *p->ainsn.insn; | |
239 | ||
240 | /* regs->nip is also adjusted if emulate_step returns 1 */ | |
241 | ret = emulate_step(regs, insn); | |
242 | if (ret > 0) { | |
243 | /* | |
244 | * Once this instruction has been boosted | |
245 | * successfully, set the boostable flag | |
246 | */ | |
247 | if (unlikely(p->ainsn.boostable == 0)) | |
248 | p->ainsn.boostable = 1; | |
249 | ||
250 | if (p->post_handler) | |
251 | p->post_handler(p, regs, 0); | |
252 | ||
253 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
254 | reset_current_kprobe(); | |
255 | preempt_enable_no_resched(); | |
256 | return 1; | |
257 | } else if (ret < 0) { | |
258 | /* | |
259 | * We don't allow kprobes on mtmsr(d)/rfi(d), etc. | |
260 | * So, we should never get here... but, its still | |
261 | * good to catch them, just in case... | |
262 | */ | |
263 | printk("Can't step on instruction %x\n", insn); | |
264 | BUG(); | |
265 | } else if (ret == 0) | |
266 | /* This instruction can't be boosted */ | |
267 | p->ainsn.boostable = -1; | |
268 | } | |
1da177e4 | 269 | prepare_singlestep(p, regs); |
0dc036c9 | 270 | kcb->kprobe_status = KPROBE_HIT_SS; |
1da177e4 LT |
271 | return 1; |
272 | ||
273 | no_kprobe: | |
d217d545 | 274 | preempt_enable_no_resched(); |
1da177e4 LT |
275 | return ret; |
276 | } | |
277 | ||
97f7943d RL |
278 | /* |
279 | * Function return probe trampoline: | |
280 | * - init_kprobes() establishes a probepoint here | |
281 | * - When the probed function returns, this probe | |
282 | * causes the handlers to fire | |
283 | */ | |
61ed9cfb TJB |
284 | asm(".global kretprobe_trampoline\n" |
285 | ".type kretprobe_trampoline, @function\n" | |
286 | "kretprobe_trampoline:\n" | |
287 | "nop\n" | |
288 | ".size kretprobe_trampoline, .-kretprobe_trampoline\n"); | |
97f7943d RL |
289 | |
290 | /* | |
291 | * Called when the probe at kretprobe trampoline is hit | |
292 | */ | |
66200ea2 AM |
293 | static int __kprobes trampoline_probe_handler(struct kprobe *p, |
294 | struct pt_regs *regs) | |
97f7943d | 295 | { |
62c27be0 | 296 | struct kretprobe_instance *ri = NULL; |
99219a3f | 297 | struct hlist_head *head, empty_rp; |
b67bfe0d | 298 | struct hlist_node *tmp; |
991a51d8 | 299 | unsigned long flags, orig_ret_address = 0; |
97f7943d RL |
300 | unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; |
301 | ||
99219a3f | 302 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 | 303 | kretprobe_hash_lock(current, &head, &flags); |
97f7943d RL |
304 | |
305 | /* | |
306 | * It is possible to have multiple instances associated with a given | |
307 | * task either because an multiple functions in the call path | |
025dfdaf | 308 | * have a return probe installed on them, and/or more than one return |
97f7943d RL |
309 | * return probe was registered for a target function. |
310 | * | |
311 | * We can handle this because: | |
312 | * - instances are always inserted at the head of the list | |
313 | * - when multiple return probes are registered for the same | |
62c27be0 | 314 | * function, the first instance's ret_addr will point to the |
97f7943d RL |
315 | * real return address, and all the rest will point to |
316 | * kretprobe_trampoline | |
317 | */ | |
b67bfe0d | 318 | hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
62c27be0 | 319 | if (ri->task != current) |
97f7943d | 320 | /* another task is sharing our hash bucket */ |
62c27be0 | 321 | continue; |
97f7943d RL |
322 | |
323 | if (ri->rp && ri->rp->handler) | |
324 | ri->rp->handler(ri, regs); | |
325 | ||
326 | orig_ret_address = (unsigned long)ri->ret_addr; | |
99219a3f | 327 | recycle_rp_inst(ri, &empty_rp); |
97f7943d RL |
328 | |
329 | if (orig_ret_address != trampoline_address) | |
330 | /* | |
331 | * This is the real return address. Any other | |
332 | * instances associated with this task are for | |
333 | * other calls deeper on the call stack | |
334 | */ | |
335 | break; | |
336 | } | |
337 | ||
0f95b7fc | 338 | kretprobe_assert(ri, orig_ret_address, trampoline_address); |
97f7943d RL |
339 | regs->nip = orig_ret_address; |
340 | ||
0dc036c9 | 341 | reset_current_kprobe(); |
ef53d9c5 | 342 | kretprobe_hash_unlock(current, &flags); |
66ff2d06 | 343 | preempt_enable_no_resched(); |
97f7943d | 344 | |
b67bfe0d | 345 | hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
99219a3f | 346 | hlist_del(&ri->hlist); |
347 | kfree(ri); | |
348 | } | |
62c27be0 | 349 | /* |
350 | * By returning a non-zero value, we are telling | |
351 | * kprobe_handler() that we don't want the post_handler | |
352 | * to run (and have re-enabled preemption) | |
353 | */ | |
354 | return 1; | |
97f7943d RL |
355 | } |
356 | ||
1da177e4 LT |
357 | /* |
358 | * Called after single-stepping. p->addr is the address of the | |
359 | * instruction whose first byte has been replaced by the "breakpoint" | |
360 | * instruction. To avoid the SMP problems that can occur when we | |
361 | * temporarily put back the original opcode to single-step, we | |
362 | * single-stepped a copy of the instruction. The address of this | |
363 | * copy is p->ainsn.insn. | |
364 | */ | |
6cc89bad | 365 | int __kprobes kprobe_post_handler(struct pt_regs *regs) |
1da177e4 | 366 | { |
0dc036c9 AM |
367 | struct kprobe *cur = kprobe_running(); |
368 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
369 | ||
6cc89bad | 370 | if (!cur || user_mode(regs)) |
1da177e4 LT |
371 | return 0; |
372 | ||
b76e59d1 KG |
373 | /* make sure we got here for instruction we have a kprobe on */ |
374 | if (((unsigned long)cur->ainsn.insn + 4) != regs->nip) | |
375 | return 0; | |
376 | ||
0dc036c9 AM |
377 | if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { |
378 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
379 | cur->post_handler(cur, regs, 0); | |
42cc2060 | 380 | } |
1da177e4 | 381 | |
db97bc7f AM |
382 | /* Adjust nip to after the single-stepped instruction */ |
383 | regs->nip = (unsigned long)cur->addr + 4; | |
0dc036c9 | 384 | regs->msr |= kcb->kprobe_saved_msr; |
1da177e4 | 385 | |
42cc2060 | 386 | /*Restore back the original saved kprobes variables and continue. */ |
0dc036c9 AM |
387 | if (kcb->kprobe_status == KPROBE_REENTER) { |
388 | restore_previous_kprobe(kcb); | |
42cc2060 PP |
389 | goto out; |
390 | } | |
0dc036c9 | 391 | reset_current_kprobe(); |
42cc2060 | 392 | out: |
1da177e4 LT |
393 | preempt_enable_no_resched(); |
394 | ||
395 | /* | |
396 | * if somebody else is singlestepping across a probe point, msr | |
f8279621 | 397 | * will have DE/SE set, in which case, continue the remaining processing |
1da177e4 LT |
398 | * of do_debug, as if this is not a probe hit. |
399 | */ | |
f8279621 | 400 | if (regs->msr & MSR_SINGLESTEP) |
1da177e4 LT |
401 | return 0; |
402 | ||
403 | return 1; | |
404 | } | |
405 | ||
9f90b997 | 406 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
1da177e4 | 407 | { |
0dc036c9 AM |
408 | struct kprobe *cur = kprobe_running(); |
409 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
50e21f2b PP |
410 | const struct exception_table_entry *entry; |
411 | ||
412 | switch(kcb->kprobe_status) { | |
413 | case KPROBE_HIT_SS: | |
414 | case KPROBE_REENTER: | |
415 | /* | |
416 | * We are here because the instruction being single | |
417 | * stepped caused a page fault. We reset the current | |
418 | * kprobe and the nip points back to the probe address | |
419 | * and allow the page fault handler to continue as a | |
420 | * normal page fault. | |
421 | */ | |
422 | regs->nip = (unsigned long)cur->addr; | |
f8279621 | 423 | regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */ |
0dc036c9 | 424 | regs->msr |= kcb->kprobe_saved_msr; |
50e21f2b PP |
425 | if (kcb->kprobe_status == KPROBE_REENTER) |
426 | restore_previous_kprobe(kcb); | |
427 | else | |
428 | reset_current_kprobe(); | |
1da177e4 | 429 | preempt_enable_no_resched(); |
50e21f2b PP |
430 | break; |
431 | case KPROBE_HIT_ACTIVE: | |
432 | case KPROBE_HIT_SSDONE: | |
433 | /* | |
434 | * We increment the nmissed count for accounting, | |
23d6d3db | 435 | * we can also use npre/npostfault count for accounting |
50e21f2b PP |
436 | * these specific fault cases. |
437 | */ | |
438 | kprobes_inc_nmissed_count(cur); | |
439 | ||
440 | /* | |
441 | * We come here because instructions in the pre/post | |
442 | * handler caused the page_fault, this could happen | |
443 | * if handler tries to access user space by | |
444 | * copy_from_user(), get_user() etc. Let the | |
445 | * user-specified handler try to fix it first. | |
446 | */ | |
447 | if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) | |
448 | return 1; | |
449 | ||
450 | /* | |
451 | * In case the user-specified fault handler returned | |
452 | * zero, try to fix up. | |
453 | */ | |
454 | if ((entry = search_exception_tables(regs->nip)) != NULL) { | |
61a92f70 | 455 | regs->nip = extable_fixup(entry); |
50e21f2b PP |
456 | return 1; |
457 | } | |
458 | ||
459 | /* | |
460 | * fixup_exception() could not handle it, | |
461 | * Let do_page_fault() fix it. | |
462 | */ | |
463 | break; | |
464 | default: | |
465 | break; | |
1da177e4 LT |
466 | } |
467 | return 0; | |
468 | } | |
469 | ||
470 | /* | |
471 | * Wrapper routine to for handling exceptions. | |
472 | */ | |
bb144a85 PP |
473 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
474 | unsigned long val, void *data) | |
1da177e4 | 475 | { |
6cc89bad | 476 | return NOTIFY_DONE; |
1da177e4 LT |
477 | } |
478 | ||
3d7e3382 ME |
479 | unsigned long arch_deref_entry_point(void *entry) |
480 | { | |
2f0143c9 | 481 | return ppc_global_function_entry(entry); |
3d7e3382 | 482 | } |
3d7e3382 | 483 | |
bb144a85 | 484 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
485 | { |
486 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
0dc036c9 | 487 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
1da177e4 | 488 | |
0dc036c9 | 489 | memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
1da177e4 LT |
490 | |
491 | /* setup return addr to the jprobe handler routine */ | |
3d7e3382 | 492 | regs->nip = arch_deref_entry_point(jp->entry); |
f55d9665 | 493 | #ifdef PPC64_ELF_ABI_v2 |
2f0143c9 | 494 | regs->gpr[12] = (unsigned long)jp->entry; |
f55d9665 | 495 | #elif defined(PPC64_ELF_ABI_v1) |
1da177e4 | 496 | regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); |
82090035 | 497 | #endif |
1da177e4 LT |
498 | |
499 | return 1; | |
500 | } | |
501 | ||
66200ea2 | 502 | void __used __kprobes jprobe_return(void) |
1da177e4 LT |
503 | { |
504 | asm volatile("trap" ::: "memory"); | |
505 | } | |
506 | ||
66200ea2 | 507 | static void __used __kprobes jprobe_return_end(void) |
1da177e4 LT |
508 | { |
509 | }; | |
510 | ||
bb144a85 | 511 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 | 512 | { |
0dc036c9 AM |
513 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
514 | ||
1da177e4 LT |
515 | /* |
516 | * FIXME - we should ideally be validating that we got here 'cos | |
517 | * of the "trap" in jprobe_return() above, before restoring the | |
518 | * saved regs... | |
519 | */ | |
0dc036c9 | 520 | memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); |
d217d545 | 521 | preempt_enable_no_resched(); |
1da177e4 LT |
522 | return 1; |
523 | } | |
97f7943d RL |
524 | |
525 | static struct kprobe trampoline_p = { | |
526 | .addr = (kprobe_opcode_t *) &kretprobe_trampoline, | |
527 | .pre_handler = trampoline_probe_handler | |
528 | }; | |
529 | ||
6772926b | 530 | int __init arch_init_kprobes(void) |
97f7943d RL |
531 | { |
532 | return register_kprobe(&trampoline_p); | |
533 | } | |
bf8f6e5b AM |
534 | |
535 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) | |
536 | { | |
537 | if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) | |
538 | return 1; | |
539 | ||
540 | return 0; | |
541 | } |