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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> |
1eeb66a1 | 33 | #include <linux/kdebug.h> |
7e1048b1 | 34 | #include <asm/cacheflush.h> |
1da177e4 | 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 | |
f438d914 MH |
41 | struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; |
42 | ||
bb144a85 | 43 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
1da177e4 | 44 | { |
63224d1e | 45 | int ret = 0; |
1da177e4 LT |
46 | kprobe_opcode_t insn = *p->addr; |
47 | ||
63224d1e AM |
48 | if ((unsigned long)p->addr & 0x03) { |
49 | printk("Attempt to register kprobe at an unaligned address\n"); | |
50 | ret = -EINVAL; | |
82090035 KG |
51 | } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) { |
52 | printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n"); | |
63224d1e AM |
53 | ret = -EINVAL; |
54 | } | |
9ec4b1f3 AM |
55 | |
56 | /* insn must be on a special executable page on ppc64 */ | |
57 | if (!ret) { | |
2d8ab6ad | 58 | p->ainsn.insn = get_insn_slot(); |
9ec4b1f3 AM |
59 | if (!p->ainsn.insn) |
60 | ret = -ENOMEM; | |
61 | } | |
1da177e4 | 62 | |
49a2a1b8 | 63 | if (!ret) { |
e6349a95 AM |
64 | memcpy(p->ainsn.insn, p->addr, |
65 | MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); | |
49a2a1b8 | 66 | p->opcode = *p->addr; |
83db3dde AM |
67 | flush_icache_range((unsigned long)p->ainsn.insn, |
68 | (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); | |
49a2a1b8 AK |
69 | } |
70 | ||
e6349a95 | 71 | p->ainsn.boostable = 0; |
49a2a1b8 | 72 | return ret; |
1da177e4 LT |
73 | } |
74 | ||
bb144a85 | 75 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
1da177e4 | 76 | { |
7e1048b1 RL |
77 | *p->addr = BREAKPOINT_INSTRUCTION; |
78 | flush_icache_range((unsigned long) p->addr, | |
79 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
1da177e4 LT |
80 | } |
81 | ||
bb144a85 | 82 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
1da177e4 LT |
83 | { |
84 | *p->addr = p->opcode; | |
7e1048b1 RL |
85 | flush_icache_range((unsigned long) p->addr, |
86 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
87 | } | |
88 | ||
0498b635 | 89 | void __kprobes arch_remove_kprobe(struct kprobe *p) |
7e1048b1 | 90 | { |
7a7d1cf9 | 91 | mutex_lock(&kprobe_mutex); |
b4c6c34a | 92 | free_insn_slot(p->ainsn.insn, 0); |
7a7d1cf9 | 93 | mutex_unlock(&kprobe_mutex); |
1da177e4 LT |
94 | } |
95 | ||
46dbe2f4 | 96 | static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
97 | { |
98 | regs->msr |= MSR_SE; | |
9ec4b1f3 | 99 | |
0ccde0a2 AM |
100 | /* |
101 | * On powerpc we should single step on the original | |
102 | * instruction even if the probed insn is a trap | |
103 | * variant as values in regs could play a part in | |
104 | * if the trap is taken or not | |
105 | */ | |
106 | regs->nip = (unsigned long)p->ainsn.insn; | |
1da177e4 LT |
107 | } |
108 | ||
46dbe2f4 | 109 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) |
0dc036c9 AM |
110 | { |
111 | kcb->prev_kprobe.kp = kprobe_running(); | |
112 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
113 | kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; | |
114 | } | |
115 | ||
46dbe2f4 | 116 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) |
42cc2060 | 117 | { |
0dc036c9 AM |
118 | __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; |
119 | kcb->kprobe_status = kcb->prev_kprobe.status; | |
120 | kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; | |
42cc2060 PP |
121 | } |
122 | ||
46dbe2f4 | 123 | static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, |
0dc036c9 | 124 | struct kprobe_ctlblk *kcb) |
42cc2060 | 125 | { |
0dc036c9 AM |
126 | __get_cpu_var(current_kprobe) = p; |
127 | kcb->kprobe_saved_msr = regs->msr; | |
42cc2060 PP |
128 | } |
129 | ||
991a51d8 | 130 | /* Called with kretprobe_lock held */ |
4c4308cb | 131 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, |
bb144a85 | 132 | struct pt_regs *regs) |
97f7943d | 133 | { |
4c4308cb CH |
134 | ri->ret_addr = (kprobe_opcode_t *)regs->link; |
135 | ||
136 | /* Replace the return addr with trampoline addr */ | |
137 | regs->link = (unsigned long)kretprobe_trampoline; | |
97f7943d RL |
138 | } |
139 | ||
46dbe2f4 | 140 | static int __kprobes kprobe_handler(struct pt_regs *regs) |
1da177e4 LT |
141 | { |
142 | struct kprobe *p; | |
143 | int ret = 0; | |
144 | unsigned int *addr = (unsigned int *)regs->nip; | |
d217d545 AM |
145 | struct kprobe_ctlblk *kcb; |
146 | ||
147 | /* | |
148 | * We don't want to be preempted for the entire | |
149 | * duration of kprobe processing | |
150 | */ | |
151 | preempt_disable(); | |
152 | kcb = get_kprobe_ctlblk(); | |
1da177e4 LT |
153 | |
154 | /* Check we're not actually recursing */ | |
155 | if (kprobe_running()) { | |
1da177e4 LT |
156 | p = get_kprobe(addr); |
157 | if (p) { | |
deac66ae | 158 | kprobe_opcode_t insn = *p->ainsn.insn; |
0dc036c9 | 159 | if (kcb->kprobe_status == KPROBE_HIT_SS && |
deac66ae | 160 | is_trap(insn)) { |
1da177e4 | 161 | regs->msr &= ~MSR_SE; |
0dc036c9 | 162 | regs->msr |= kcb->kprobe_saved_msr; |
1da177e4 LT |
163 | goto no_kprobe; |
164 | } | |
42cc2060 PP |
165 | /* We have reentered the kprobe_handler(), since |
166 | * another probe was hit while within the handler. | |
167 | * We here save the original kprobes variables and | |
168 | * just single step on the instruction of the new probe | |
169 | * without calling any user handlers. | |
170 | */ | |
0dc036c9 AM |
171 | save_previous_kprobe(kcb); |
172 | set_current_kprobe(p, regs, kcb); | |
173 | kcb->kprobe_saved_msr = regs->msr; | |
bf8d5c52 | 174 | kprobes_inc_nmissed_count(p); |
42cc2060 | 175 | prepare_singlestep(p, regs); |
0dc036c9 | 176 | kcb->kprobe_status = KPROBE_REENTER; |
42cc2060 | 177 | return 1; |
1da177e4 | 178 | } else { |
eb3a7292 KA |
179 | if (*addr != BREAKPOINT_INSTRUCTION) { |
180 | /* If trap variant, then it belongs not to us */ | |
181 | kprobe_opcode_t cur_insn = *addr; | |
182 | if (is_trap(cur_insn)) | |
183 | goto no_kprobe; | |
184 | /* The breakpoint instruction was removed by | |
185 | * another cpu right after we hit, no further | |
186 | * handling of this interrupt is appropriate | |
187 | */ | |
188 | ret = 1; | |
189 | goto no_kprobe; | |
190 | } | |
0dc036c9 | 191 | p = __get_cpu_var(current_kprobe); |
1da177e4 LT |
192 | if (p->break_handler && p->break_handler(p, regs)) { |
193 | goto ss_probe; | |
194 | } | |
195 | } | |
1da177e4 LT |
196 | goto no_kprobe; |
197 | } | |
198 | ||
1da177e4 LT |
199 | p = get_kprobe(addr); |
200 | if (!p) { | |
1da177e4 LT |
201 | if (*addr != BREAKPOINT_INSTRUCTION) { |
202 | /* | |
203 | * PowerPC has multiple variants of the "trap" | |
204 | * instruction. If the current instruction is a | |
205 | * trap variant, it could belong to someone else | |
206 | */ | |
207 | kprobe_opcode_t cur_insn = *addr; | |
deac66ae | 208 | if (is_trap(cur_insn)) |
1da177e4 LT |
209 | goto no_kprobe; |
210 | /* | |
211 | * The breakpoint instruction was removed right | |
212 | * after we hit it. Another cpu has removed | |
213 | * either a probepoint or a debugger breakpoint | |
214 | * at this address. In either case, no further | |
215 | * handling of this interrupt is appropriate. | |
216 | */ | |
217 | ret = 1; | |
218 | } | |
219 | /* Not one of ours: let kernel handle it */ | |
220 | goto no_kprobe; | |
221 | } | |
222 | ||
0dc036c9 AM |
223 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
224 | set_current_kprobe(p, regs, kcb); | |
1da177e4 LT |
225 | if (p->pre_handler && p->pre_handler(p, regs)) |
226 | /* handler has already set things up, so skip ss setup */ | |
227 | return 1; | |
228 | ||
229 | ss_probe: | |
e6349a95 AM |
230 | if (p->ainsn.boostable >= 0) { |
231 | unsigned int insn = *p->ainsn.insn; | |
232 | ||
233 | /* regs->nip is also adjusted if emulate_step returns 1 */ | |
234 | ret = emulate_step(regs, insn); | |
235 | if (ret > 0) { | |
236 | /* | |
237 | * Once this instruction has been boosted | |
238 | * successfully, set the boostable flag | |
239 | */ | |
240 | if (unlikely(p->ainsn.boostable == 0)) | |
241 | p->ainsn.boostable = 1; | |
242 | ||
243 | if (p->post_handler) | |
244 | p->post_handler(p, regs, 0); | |
245 | ||
246 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
247 | reset_current_kprobe(); | |
248 | preempt_enable_no_resched(); | |
249 | return 1; | |
250 | } else if (ret < 0) { | |
251 | /* | |
252 | * We don't allow kprobes on mtmsr(d)/rfi(d), etc. | |
253 | * So, we should never get here... but, its still | |
254 | * good to catch them, just in case... | |
255 | */ | |
256 | printk("Can't step on instruction %x\n", insn); | |
257 | BUG(); | |
258 | } else if (ret == 0) | |
259 | /* This instruction can't be boosted */ | |
260 | p->ainsn.boostable = -1; | |
261 | } | |
1da177e4 | 262 | prepare_singlestep(p, regs); |
0dc036c9 | 263 | kcb->kprobe_status = KPROBE_HIT_SS; |
1da177e4 LT |
264 | return 1; |
265 | ||
266 | no_kprobe: | |
d217d545 | 267 | preempt_enable_no_resched(); |
1da177e4 LT |
268 | return ret; |
269 | } | |
270 | ||
97f7943d RL |
271 | /* |
272 | * Function return probe trampoline: | |
273 | * - init_kprobes() establishes a probepoint here | |
274 | * - When the probed function returns, this probe | |
275 | * causes the handlers to fire | |
276 | */ | |
277 | void kretprobe_trampoline_holder(void) | |
278 | { | |
279 | asm volatile(".global kretprobe_trampoline\n" | |
280 | "kretprobe_trampoline:\n" | |
281 | "nop\n"); | |
282 | } | |
283 | ||
284 | /* | |
285 | * Called when the probe at kretprobe trampoline is hit | |
286 | */ | |
bb144a85 | 287 | int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) |
97f7943d | 288 | { |
62c27be0 | 289 | struct kretprobe_instance *ri = NULL; |
99219a3f | 290 | struct hlist_head *head, empty_rp; |
62c27be0 | 291 | struct hlist_node *node, *tmp; |
991a51d8 | 292 | unsigned long flags, orig_ret_address = 0; |
97f7943d RL |
293 | unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; |
294 | ||
99219a3f | 295 | INIT_HLIST_HEAD(&empty_rp); |
991a51d8 | 296 | spin_lock_irqsave(&kretprobe_lock, flags); |
62c27be0 | 297 | head = kretprobe_inst_table_head(current); |
97f7943d RL |
298 | |
299 | /* | |
300 | * It is possible to have multiple instances associated with a given | |
301 | * task either because an multiple functions in the call path | |
302 | * have a return probe installed on them, and/or more then one return | |
303 | * return probe was registered for a target function. | |
304 | * | |
305 | * We can handle this because: | |
306 | * - instances are always inserted at the head of the list | |
307 | * - when multiple return probes are registered for the same | |
62c27be0 | 308 | * function, the first instance's ret_addr will point to the |
97f7943d RL |
309 | * real return address, and all the rest will point to |
310 | * kretprobe_trampoline | |
311 | */ | |
312 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
62c27be0 | 313 | if (ri->task != current) |
97f7943d | 314 | /* another task is sharing our hash bucket */ |
62c27be0 | 315 | continue; |
97f7943d RL |
316 | |
317 | if (ri->rp && ri->rp->handler) | |
318 | ri->rp->handler(ri, regs); | |
319 | ||
320 | orig_ret_address = (unsigned long)ri->ret_addr; | |
99219a3f | 321 | recycle_rp_inst(ri, &empty_rp); |
97f7943d RL |
322 | |
323 | if (orig_ret_address != trampoline_address) | |
324 | /* | |
325 | * This is the real return address. Any other | |
326 | * instances associated with this task are for | |
327 | * other calls deeper on the call stack | |
328 | */ | |
329 | break; | |
330 | } | |
331 | ||
0f95b7fc | 332 | kretprobe_assert(ri, orig_ret_address, trampoline_address); |
97f7943d RL |
333 | regs->nip = orig_ret_address; |
334 | ||
0dc036c9 | 335 | reset_current_kprobe(); |
991a51d8 | 336 | spin_unlock_irqrestore(&kretprobe_lock, flags); |
66ff2d06 | 337 | preempt_enable_no_resched(); |
97f7943d | 338 | |
99219a3f | 339 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
340 | hlist_del(&ri->hlist); | |
341 | kfree(ri); | |
342 | } | |
62c27be0 | 343 | /* |
344 | * By returning a non-zero value, we are telling | |
345 | * kprobe_handler() that we don't want the post_handler | |
346 | * to run (and have re-enabled preemption) | |
347 | */ | |
348 | return 1; | |
97f7943d RL |
349 | } |
350 | ||
1da177e4 LT |
351 | /* |
352 | * Called after single-stepping. p->addr is the address of the | |
353 | * instruction whose first byte has been replaced by the "breakpoint" | |
354 | * instruction. To avoid the SMP problems that can occur when we | |
355 | * temporarily put back the original opcode to single-step, we | |
356 | * single-stepped a copy of the instruction. The address of this | |
357 | * copy is p->ainsn.insn. | |
358 | */ | |
bb144a85 | 359 | static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
360 | { |
361 | int ret; | |
9ec4b1f3 | 362 | unsigned int insn = *p->ainsn.insn; |
1da177e4 LT |
363 | |
364 | regs->nip = (unsigned long)p->addr; | |
9ec4b1f3 | 365 | ret = emulate_step(regs, insn); |
1da177e4 LT |
366 | if (ret == 0) |
367 | regs->nip = (unsigned long)p->addr + 4; | |
1da177e4 LT |
368 | } |
369 | ||
46dbe2f4 | 370 | static int __kprobes post_kprobe_handler(struct pt_regs *regs) |
1da177e4 | 371 | { |
0dc036c9 AM |
372 | struct kprobe *cur = kprobe_running(); |
373 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
374 | ||
375 | if (!cur) | |
1da177e4 LT |
376 | return 0; |
377 | ||
0dc036c9 AM |
378 | if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { |
379 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
380 | cur->post_handler(cur, regs, 0); | |
42cc2060 | 381 | } |
1da177e4 | 382 | |
0dc036c9 AM |
383 | resume_execution(cur, regs); |
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 | |
397 | * will have SE set, in which case, continue the remaining processing | |
398 | * of do_debug, as if this is not a probe hit. | |
399 | */ | |
400 | if (regs->msr & MSR_SE) | |
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; | |
f829fd23 | 423 | regs->msr &= ~MSR_SE; |
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, | |
435 | * we can also use npre/npostfault count for accouting | |
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) { | |
455 | regs->nip = entry->fixup; | |
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 LT |
475 | { |
476 | struct die_args *args = (struct die_args *)data; | |
477 | int ret = NOTIFY_DONE; | |
478 | ||
2326c770 | 479 | if (args->regs && user_mode(args->regs)) |
480 | return ret; | |
481 | ||
1da177e4 | 482 | switch (val) { |
1da177e4 LT |
483 | case DIE_BPT: |
484 | if (kprobe_handler(args->regs)) | |
485 | ret = NOTIFY_STOP; | |
486 | break; | |
487 | case DIE_SSTEP: | |
488 | if (post_kprobe_handler(args->regs)) | |
489 | ret = NOTIFY_STOP; | |
490 | break; | |
1da177e4 LT |
491 | default: |
492 | break; | |
493 | } | |
1da177e4 LT |
494 | return ret; |
495 | } | |
496 | ||
3d7e3382 ME |
497 | #ifdef CONFIG_PPC64 |
498 | unsigned long arch_deref_entry_point(void *entry) | |
499 | { | |
500 | return (unsigned long)(((func_descr_t *)entry)->entry); | |
501 | } | |
502 | #endif | |
503 | ||
bb144a85 | 504 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
505 | { |
506 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
0dc036c9 | 507 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
1da177e4 | 508 | |
0dc036c9 | 509 | memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
1da177e4 LT |
510 | |
511 | /* setup return addr to the jprobe handler routine */ | |
3d7e3382 | 512 | regs->nip = arch_deref_entry_point(jp->entry); |
82090035 | 513 | #ifdef CONFIG_PPC64 |
1da177e4 | 514 | regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); |
82090035 | 515 | #endif |
1da177e4 LT |
516 | |
517 | return 1; | |
518 | } | |
519 | ||
bb144a85 | 520 | void __kprobes jprobe_return(void) |
1da177e4 LT |
521 | { |
522 | asm volatile("trap" ::: "memory"); | |
523 | } | |
524 | ||
bb144a85 | 525 | void __kprobes jprobe_return_end(void) |
1da177e4 LT |
526 | { |
527 | }; | |
528 | ||
bb144a85 | 529 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 | 530 | { |
0dc036c9 AM |
531 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
532 | ||
1da177e4 LT |
533 | /* |
534 | * FIXME - we should ideally be validating that we got here 'cos | |
535 | * of the "trap" in jprobe_return() above, before restoring the | |
536 | * saved regs... | |
537 | */ | |
0dc036c9 | 538 | memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); |
d217d545 | 539 | preempt_enable_no_resched(); |
1da177e4 LT |
540 | return 1; |
541 | } | |
97f7943d RL |
542 | |
543 | static struct kprobe trampoline_p = { | |
544 | .addr = (kprobe_opcode_t *) &kretprobe_trampoline, | |
545 | .pre_handler = trampoline_probe_handler | |
546 | }; | |
547 | ||
6772926b | 548 | int __init arch_init_kprobes(void) |
97f7943d RL |
549 | { |
550 | return register_kprobe(&trampoline_p); | |
551 | } | |
bf8f6e5b AM |
552 | |
553 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) | |
554 | { | |
555 | if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) | |
556 | return 1; | |
557 | ||
558 | return 0; | |
559 | } |