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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> |
5a0e3ad6 | 34 | #include <linux/slab.h> |
7e1048b1 | 35 | #include <asm/cacheflush.h> |
1da177e4 | 36 | #include <asm/sstep.h> |
50e21f2b | 37 | #include <asm/uaccess.h> |
f8279621 KG |
38 | #include <asm/system.h> |
39 | ||
172ae2e7 | 40 | #ifdef CONFIG_PPC_ADV_DEBUG_REGS |
f8279621 KG |
41 | #define MSR_SINGLESTEP (MSR_DE) |
42 | #else | |
43 | #define MSR_SINGLESTEP (MSR_SE) | |
44 | #endif | |
1da177e4 | 45 | |
0dc036c9 AM |
46 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
47 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); | |
1da177e4 | 48 | |
f438d914 MH |
49 | struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; |
50 | ||
bb144a85 | 51 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
1da177e4 | 52 | { |
63224d1e | 53 | int ret = 0; |
1da177e4 LT |
54 | kprobe_opcode_t insn = *p->addr; |
55 | ||
63224d1e AM |
56 | if ((unsigned long)p->addr & 0x03) { |
57 | printk("Attempt to register kprobe at an unaligned address\n"); | |
58 | ret = -EINVAL; | |
82090035 KG |
59 | } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) { |
60 | printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n"); | |
63224d1e AM |
61 | ret = -EINVAL; |
62 | } | |
9ec4b1f3 | 63 | |
f8279621 KG |
64 | /* insn must be on a special executable page on ppc64. This is |
65 | * not explicitly required on ppc32 (right now), but it doesn't hurt */ | |
9ec4b1f3 | 66 | if (!ret) { |
2d8ab6ad | 67 | p->ainsn.insn = get_insn_slot(); |
9ec4b1f3 AM |
68 | if (!p->ainsn.insn) |
69 | ret = -ENOMEM; | |
70 | } | |
1da177e4 | 71 | |
49a2a1b8 | 72 | if (!ret) { |
e6349a95 AM |
73 | memcpy(p->ainsn.insn, p->addr, |
74 | MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); | |
49a2a1b8 | 75 | p->opcode = *p->addr; |
83db3dde AM |
76 | flush_icache_range((unsigned long)p->ainsn.insn, |
77 | (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t)); | |
49a2a1b8 AK |
78 | } |
79 | ||
e6349a95 | 80 | p->ainsn.boostable = 0; |
49a2a1b8 | 81 | return ret; |
1da177e4 LT |
82 | } |
83 | ||
bb144a85 | 84 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
1da177e4 | 85 | { |
7e1048b1 RL |
86 | *p->addr = BREAKPOINT_INSTRUCTION; |
87 | flush_icache_range((unsigned long) p->addr, | |
88 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
1da177e4 LT |
89 | } |
90 | ||
bb144a85 | 91 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
1da177e4 LT |
92 | { |
93 | *p->addr = p->opcode; | |
7e1048b1 RL |
94 | flush_icache_range((unsigned long) p->addr, |
95 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); | |
96 | } | |
97 | ||
0498b635 | 98 | void __kprobes arch_remove_kprobe(struct kprobe *p) |
7e1048b1 | 99 | { |
12941560 MH |
100 | if (p->ainsn.insn) { |
101 | free_insn_slot(p->ainsn.insn, 0); | |
102 | p->ainsn.insn = NULL; | |
103 | } | |
1da177e4 LT |
104 | } |
105 | ||
46dbe2f4 | 106 | static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
1da177e4 | 107 | { |
b76e59d1 KG |
108 | /* We turn off async exceptions to ensure that the single step will |
109 | * be for the instruction we have the kprobe on, if we dont its | |
110 | * possible we'd get the single step reported for an exception handler | |
111 | * like Decrementer or External Interrupt */ | |
112 | regs->msr &= ~MSR_EE; | |
f8279621 | 113 | regs->msr |= MSR_SINGLESTEP; |
172ae2e7 | 114 | #ifdef CONFIG_PPC_ADV_DEBUG_REGS |
f8279621 KG |
115 | regs->msr &= ~MSR_CE; |
116 | mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); | |
117 | #endif | |
9ec4b1f3 | 118 | |
0ccde0a2 AM |
119 | /* |
120 | * On powerpc we should single step on the original | |
121 | * instruction even if the probed insn is a trap | |
122 | * variant as values in regs could play a part in | |
123 | * if the trap is taken or not | |
124 | */ | |
125 | regs->nip = (unsigned long)p->ainsn.insn; | |
1da177e4 LT |
126 | } |
127 | ||
46dbe2f4 | 128 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) |
0dc036c9 AM |
129 | { |
130 | kcb->prev_kprobe.kp = kprobe_running(); | |
131 | kcb->prev_kprobe.status = kcb->kprobe_status; | |
132 | kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; | |
133 | } | |
134 | ||
46dbe2f4 | 135 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) |
42cc2060 | 136 | { |
0dc036c9 AM |
137 | __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; |
138 | kcb->kprobe_status = kcb->prev_kprobe.status; | |
139 | kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; | |
42cc2060 PP |
140 | } |
141 | ||
46dbe2f4 | 142 | static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, |
0dc036c9 | 143 | struct kprobe_ctlblk *kcb) |
42cc2060 | 144 | { |
0dc036c9 AM |
145 | __get_cpu_var(current_kprobe) = p; |
146 | kcb->kprobe_saved_msr = regs->msr; | |
42cc2060 PP |
147 | } |
148 | ||
4c4308cb | 149 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, |
bb144a85 | 150 | struct pt_regs *regs) |
97f7943d | 151 | { |
4c4308cb CH |
152 | ri->ret_addr = (kprobe_opcode_t *)regs->link; |
153 | ||
154 | /* Replace the return addr with trampoline addr */ | |
155 | regs->link = (unsigned long)kretprobe_trampoline; | |
97f7943d RL |
156 | } |
157 | ||
46dbe2f4 | 158 | static int __kprobes kprobe_handler(struct pt_regs *regs) |
1da177e4 LT |
159 | { |
160 | struct kprobe *p; | |
161 | int ret = 0; | |
162 | unsigned int *addr = (unsigned int *)regs->nip; | |
d217d545 AM |
163 | struct kprobe_ctlblk *kcb; |
164 | ||
165 | /* | |
166 | * We don't want to be preempted for the entire | |
167 | * duration of kprobe processing | |
168 | */ | |
169 | preempt_disable(); | |
170 | kcb = get_kprobe_ctlblk(); | |
1da177e4 LT |
171 | |
172 | /* Check we're not actually recursing */ | |
173 | if (kprobe_running()) { | |
1da177e4 LT |
174 | p = get_kprobe(addr); |
175 | if (p) { | |
deac66ae | 176 | kprobe_opcode_t insn = *p->ainsn.insn; |
0dc036c9 | 177 | if (kcb->kprobe_status == KPROBE_HIT_SS && |
deac66ae | 178 | is_trap(insn)) { |
f8279621 KG |
179 | /* Turn off 'trace' bits */ |
180 | regs->msr &= ~MSR_SINGLESTEP; | |
0dc036c9 | 181 | regs->msr |= kcb->kprobe_saved_msr; |
1da177e4 LT |
182 | goto no_kprobe; |
183 | } | |
42cc2060 PP |
184 | /* We have reentered the kprobe_handler(), since |
185 | * another probe was hit while within the handler. | |
186 | * We here save the original kprobes variables and | |
187 | * just single step on the instruction of the new probe | |
188 | * without calling any user handlers. | |
189 | */ | |
0dc036c9 AM |
190 | save_previous_kprobe(kcb); |
191 | set_current_kprobe(p, regs, kcb); | |
192 | kcb->kprobe_saved_msr = regs->msr; | |
bf8d5c52 | 193 | kprobes_inc_nmissed_count(p); |
42cc2060 | 194 | prepare_singlestep(p, regs); |
0dc036c9 | 195 | kcb->kprobe_status = KPROBE_REENTER; |
42cc2060 | 196 | return 1; |
1da177e4 | 197 | } else { |
eb3a7292 KA |
198 | if (*addr != BREAKPOINT_INSTRUCTION) { |
199 | /* If trap variant, then it belongs not to us */ | |
200 | kprobe_opcode_t cur_insn = *addr; | |
201 | if (is_trap(cur_insn)) | |
202 | goto no_kprobe; | |
203 | /* The breakpoint instruction was removed by | |
204 | * another cpu right after we hit, no further | |
205 | * handling of this interrupt is appropriate | |
206 | */ | |
207 | ret = 1; | |
208 | goto no_kprobe; | |
209 | } | |
0dc036c9 | 210 | p = __get_cpu_var(current_kprobe); |
1da177e4 LT |
211 | if (p->break_handler && p->break_handler(p, regs)) { |
212 | goto ss_probe; | |
213 | } | |
214 | } | |
1da177e4 LT |
215 | goto no_kprobe; |
216 | } | |
217 | ||
1da177e4 LT |
218 | p = get_kprobe(addr); |
219 | if (!p) { | |
1da177e4 LT |
220 | if (*addr != BREAKPOINT_INSTRUCTION) { |
221 | /* | |
222 | * PowerPC has multiple variants of the "trap" | |
223 | * instruction. If the current instruction is a | |
224 | * trap variant, it could belong to someone else | |
225 | */ | |
226 | kprobe_opcode_t cur_insn = *addr; | |
deac66ae | 227 | if (is_trap(cur_insn)) |
1da177e4 LT |
228 | goto no_kprobe; |
229 | /* | |
230 | * The breakpoint instruction was removed right | |
231 | * after we hit it. Another cpu has removed | |
232 | * either a probepoint or a debugger breakpoint | |
233 | * at this address. In either case, no further | |
234 | * handling of this interrupt is appropriate. | |
235 | */ | |
236 | ret = 1; | |
237 | } | |
238 | /* Not one of ours: let kernel handle it */ | |
239 | goto no_kprobe; | |
240 | } | |
241 | ||
0dc036c9 AM |
242 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
243 | set_current_kprobe(p, regs, kcb); | |
1da177e4 LT |
244 | if (p->pre_handler && p->pre_handler(p, regs)) |
245 | /* handler has already set things up, so skip ss setup */ | |
246 | return 1; | |
247 | ||
248 | ss_probe: | |
e6349a95 AM |
249 | if (p->ainsn.boostable >= 0) { |
250 | unsigned int insn = *p->ainsn.insn; | |
251 | ||
252 | /* regs->nip is also adjusted if emulate_step returns 1 */ | |
253 | ret = emulate_step(regs, insn); | |
254 | if (ret > 0) { | |
255 | /* | |
256 | * Once this instruction has been boosted | |
257 | * successfully, set the boostable flag | |
258 | */ | |
259 | if (unlikely(p->ainsn.boostable == 0)) | |
260 | p->ainsn.boostable = 1; | |
261 | ||
262 | if (p->post_handler) | |
263 | p->post_handler(p, regs, 0); | |
264 | ||
265 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
266 | reset_current_kprobe(); | |
267 | preempt_enable_no_resched(); | |
268 | return 1; | |
269 | } else if (ret < 0) { | |
270 | /* | |
271 | * We don't allow kprobes on mtmsr(d)/rfi(d), etc. | |
272 | * So, we should never get here... but, its still | |
273 | * good to catch them, just in case... | |
274 | */ | |
275 | printk("Can't step on instruction %x\n", insn); | |
276 | BUG(); | |
277 | } else if (ret == 0) | |
278 | /* This instruction can't be boosted */ | |
279 | p->ainsn.boostable = -1; | |
280 | } | |
1da177e4 | 281 | prepare_singlestep(p, regs); |
0dc036c9 | 282 | kcb->kprobe_status = KPROBE_HIT_SS; |
1da177e4 LT |
283 | return 1; |
284 | ||
285 | no_kprobe: | |
d217d545 | 286 | preempt_enable_no_resched(); |
1da177e4 LT |
287 | return ret; |
288 | } | |
289 | ||
97f7943d RL |
290 | /* |
291 | * Function return probe trampoline: | |
292 | * - init_kprobes() establishes a probepoint here | |
293 | * - When the probed function returns, this probe | |
294 | * causes the handlers to fire | |
295 | */ | |
66200ea2 | 296 | static void __used kretprobe_trampoline_holder(void) |
97f7943d RL |
297 | { |
298 | asm volatile(".global kretprobe_trampoline\n" | |
299 | "kretprobe_trampoline:\n" | |
300 | "nop\n"); | |
301 | } | |
302 | ||
303 | /* | |
304 | * Called when the probe at kretprobe trampoline is hit | |
305 | */ | |
66200ea2 AM |
306 | static int __kprobes trampoline_probe_handler(struct kprobe *p, |
307 | struct pt_regs *regs) | |
97f7943d | 308 | { |
62c27be0 | 309 | struct kretprobe_instance *ri = NULL; |
99219a3f | 310 | struct hlist_head *head, empty_rp; |
62c27be0 | 311 | struct hlist_node *node, *tmp; |
991a51d8 | 312 | unsigned long flags, orig_ret_address = 0; |
97f7943d RL |
313 | unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; |
314 | ||
99219a3f | 315 | INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5 | 316 | kretprobe_hash_lock(current, &head, &flags); |
97f7943d RL |
317 | |
318 | /* | |
319 | * It is possible to have multiple instances associated with a given | |
320 | * task either because an multiple functions in the call path | |
025dfdaf | 321 | * have a return probe installed on them, and/or more than one return |
97f7943d RL |
322 | * return probe was registered for a target function. |
323 | * | |
324 | * We can handle this because: | |
325 | * - instances are always inserted at the head of the list | |
326 | * - when multiple return probes are registered for the same | |
62c27be0 | 327 | * function, the first instance's ret_addr will point to the |
97f7943d RL |
328 | * real return address, and all the rest will point to |
329 | * kretprobe_trampoline | |
330 | */ | |
331 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { | |
62c27be0 | 332 | if (ri->task != current) |
97f7943d | 333 | /* another task is sharing our hash bucket */ |
62c27be0 | 334 | continue; |
97f7943d RL |
335 | |
336 | if (ri->rp && ri->rp->handler) | |
337 | ri->rp->handler(ri, regs); | |
338 | ||
339 | orig_ret_address = (unsigned long)ri->ret_addr; | |
99219a3f | 340 | recycle_rp_inst(ri, &empty_rp); |
97f7943d RL |
341 | |
342 | if (orig_ret_address != trampoline_address) | |
343 | /* | |
344 | * This is the real return address. Any other | |
345 | * instances associated with this task are for | |
346 | * other calls deeper on the call stack | |
347 | */ | |
348 | break; | |
349 | } | |
350 | ||
0f95b7fc | 351 | kretprobe_assert(ri, orig_ret_address, trampoline_address); |
97f7943d RL |
352 | regs->nip = orig_ret_address; |
353 | ||
0dc036c9 | 354 | reset_current_kprobe(); |
ef53d9c5 | 355 | kretprobe_hash_unlock(current, &flags); |
66ff2d06 | 356 | preempt_enable_no_resched(); |
97f7943d | 357 | |
99219a3f | 358 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
359 | hlist_del(&ri->hlist); | |
360 | kfree(ri); | |
361 | } | |
62c27be0 | 362 | /* |
363 | * By returning a non-zero value, we are telling | |
364 | * kprobe_handler() that we don't want the post_handler | |
365 | * to run (and have re-enabled preemption) | |
366 | */ | |
367 | return 1; | |
97f7943d RL |
368 | } |
369 | ||
1da177e4 LT |
370 | /* |
371 | * Called after single-stepping. p->addr is the address of the | |
372 | * instruction whose first byte has been replaced by the "breakpoint" | |
373 | * instruction. To avoid the SMP problems that can occur when we | |
374 | * temporarily put back the original opcode to single-step, we | |
375 | * single-stepped a copy of the instruction. The address of this | |
376 | * copy is p->ainsn.insn. | |
377 | */ | |
bb144a85 | 378 | static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
379 | { |
380 | int ret; | |
9ec4b1f3 | 381 | unsigned int insn = *p->ainsn.insn; |
1da177e4 LT |
382 | |
383 | regs->nip = (unsigned long)p->addr; | |
9ec4b1f3 | 384 | ret = emulate_step(regs, insn); |
1da177e4 LT |
385 | if (ret == 0) |
386 | regs->nip = (unsigned long)p->addr + 4; | |
1da177e4 LT |
387 | } |
388 | ||
46dbe2f4 | 389 | static int __kprobes post_kprobe_handler(struct pt_regs *regs) |
1da177e4 | 390 | { |
0dc036c9 AM |
391 | struct kprobe *cur = kprobe_running(); |
392 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
393 | ||
394 | if (!cur) | |
1da177e4 LT |
395 | return 0; |
396 | ||
b76e59d1 KG |
397 | /* make sure we got here for instruction we have a kprobe on */ |
398 | if (((unsigned long)cur->ainsn.insn + 4) != regs->nip) | |
399 | return 0; | |
400 | ||
0dc036c9 AM |
401 | if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { |
402 | kcb->kprobe_status = KPROBE_HIT_SSDONE; | |
403 | cur->post_handler(cur, regs, 0); | |
42cc2060 | 404 | } |
1da177e4 | 405 | |
0dc036c9 AM |
406 | resume_execution(cur, regs); |
407 | regs->msr |= kcb->kprobe_saved_msr; | |
1da177e4 | 408 | |
42cc2060 | 409 | /*Restore back the original saved kprobes variables and continue. */ |
0dc036c9 AM |
410 | if (kcb->kprobe_status == KPROBE_REENTER) { |
411 | restore_previous_kprobe(kcb); | |
42cc2060 PP |
412 | goto out; |
413 | } | |
0dc036c9 | 414 | reset_current_kprobe(); |
42cc2060 | 415 | out: |
1da177e4 LT |
416 | preempt_enable_no_resched(); |
417 | ||
418 | /* | |
419 | * if somebody else is singlestepping across a probe point, msr | |
f8279621 | 420 | * will have DE/SE set, in which case, continue the remaining processing |
1da177e4 LT |
421 | * of do_debug, as if this is not a probe hit. |
422 | */ | |
f8279621 | 423 | if (regs->msr & MSR_SINGLESTEP) |
1da177e4 LT |
424 | return 0; |
425 | ||
426 | return 1; | |
427 | } | |
428 | ||
9f90b997 | 429 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
1da177e4 | 430 | { |
0dc036c9 AM |
431 | struct kprobe *cur = kprobe_running(); |
432 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); | |
50e21f2b PP |
433 | const struct exception_table_entry *entry; |
434 | ||
435 | switch(kcb->kprobe_status) { | |
436 | case KPROBE_HIT_SS: | |
437 | case KPROBE_REENTER: | |
438 | /* | |
439 | * We are here because the instruction being single | |
440 | * stepped caused a page fault. We reset the current | |
441 | * kprobe and the nip points back to the probe address | |
442 | * and allow the page fault handler to continue as a | |
443 | * normal page fault. | |
444 | */ | |
445 | regs->nip = (unsigned long)cur->addr; | |
f8279621 | 446 | regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */ |
0dc036c9 | 447 | regs->msr |= kcb->kprobe_saved_msr; |
50e21f2b PP |
448 | if (kcb->kprobe_status == KPROBE_REENTER) |
449 | restore_previous_kprobe(kcb); | |
450 | else | |
451 | reset_current_kprobe(); | |
1da177e4 | 452 | preempt_enable_no_resched(); |
50e21f2b PP |
453 | break; |
454 | case KPROBE_HIT_ACTIVE: | |
455 | case KPROBE_HIT_SSDONE: | |
456 | /* | |
457 | * We increment the nmissed count for accounting, | |
458 | * we can also use npre/npostfault count for accouting | |
459 | * these specific fault cases. | |
460 | */ | |
461 | kprobes_inc_nmissed_count(cur); | |
462 | ||
463 | /* | |
464 | * We come here because instructions in the pre/post | |
465 | * handler caused the page_fault, this could happen | |
466 | * if handler tries to access user space by | |
467 | * copy_from_user(), get_user() etc. Let the | |
468 | * user-specified handler try to fix it first. | |
469 | */ | |
470 | if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) | |
471 | return 1; | |
472 | ||
473 | /* | |
474 | * In case the user-specified fault handler returned | |
475 | * zero, try to fix up. | |
476 | */ | |
477 | if ((entry = search_exception_tables(regs->nip)) != NULL) { | |
478 | regs->nip = entry->fixup; | |
479 | return 1; | |
480 | } | |
481 | ||
482 | /* | |
483 | * fixup_exception() could not handle it, | |
484 | * Let do_page_fault() fix it. | |
485 | */ | |
486 | break; | |
487 | default: | |
488 | break; | |
1da177e4 LT |
489 | } |
490 | return 0; | |
491 | } | |
492 | ||
493 | /* | |
494 | * Wrapper routine to for handling exceptions. | |
495 | */ | |
bb144a85 PP |
496 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
497 | unsigned long val, void *data) | |
1da177e4 LT |
498 | { |
499 | struct die_args *args = (struct die_args *)data; | |
500 | int ret = NOTIFY_DONE; | |
501 | ||
2326c770 | 502 | if (args->regs && user_mode(args->regs)) |
503 | return ret; | |
504 | ||
1da177e4 | 505 | switch (val) { |
1da177e4 LT |
506 | case DIE_BPT: |
507 | if (kprobe_handler(args->regs)) | |
508 | ret = NOTIFY_STOP; | |
509 | break; | |
510 | case DIE_SSTEP: | |
511 | if (post_kprobe_handler(args->regs)) | |
512 | ret = NOTIFY_STOP; | |
513 | break; | |
1da177e4 LT |
514 | default: |
515 | break; | |
516 | } | |
1da177e4 LT |
517 | return ret; |
518 | } | |
519 | ||
3d7e3382 ME |
520 | #ifdef CONFIG_PPC64 |
521 | unsigned long arch_deref_entry_point(void *entry) | |
522 | { | |
80d267f9 | 523 | return ((func_descr_t *)entry)->entry; |
3d7e3382 ME |
524 | } |
525 | #endif | |
526 | ||
bb144a85 | 527 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 LT |
528 | { |
529 | struct jprobe *jp = container_of(p, struct jprobe, kp); | |
0dc036c9 | 530 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
1da177e4 | 531 | |
0dc036c9 | 532 | memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
1da177e4 LT |
533 | |
534 | /* setup return addr to the jprobe handler routine */ | |
3d7e3382 | 535 | regs->nip = arch_deref_entry_point(jp->entry); |
82090035 | 536 | #ifdef CONFIG_PPC64 |
1da177e4 | 537 | regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); |
82090035 | 538 | #endif |
1da177e4 LT |
539 | |
540 | return 1; | |
541 | } | |
542 | ||
66200ea2 | 543 | void __used __kprobes jprobe_return(void) |
1da177e4 LT |
544 | { |
545 | asm volatile("trap" ::: "memory"); | |
546 | } | |
547 | ||
66200ea2 | 548 | static void __used __kprobes jprobe_return_end(void) |
1da177e4 LT |
549 | { |
550 | }; | |
551 | ||
bb144a85 | 552 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
1da177e4 | 553 | { |
0dc036c9 AM |
554 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
555 | ||
1da177e4 LT |
556 | /* |
557 | * FIXME - we should ideally be validating that we got here 'cos | |
558 | * of the "trap" in jprobe_return() above, before restoring the | |
559 | * saved regs... | |
560 | */ | |
0dc036c9 | 561 | memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); |
d217d545 | 562 | preempt_enable_no_resched(); |
1da177e4 LT |
563 | return 1; |
564 | } | |
97f7943d RL |
565 | |
566 | static struct kprobe trampoline_p = { | |
567 | .addr = (kprobe_opcode_t *) &kretprobe_trampoline, | |
568 | .pre_handler = trampoline_probe_handler | |
569 | }; | |
570 | ||
6772926b | 571 | int __init arch_init_kprobes(void) |
97f7943d RL |
572 | { |
573 | return register_kprobe(&trampoline_p); | |
574 | } | |
bf8f6e5b AM |
575 | |
576 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) | |
577 | { | |
578 | if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) | |
579 | return 1; | |
580 | ||
581 | return 0; | |
582 | } |