1 /* MN10300 Kernel probes implementation
2 *
3 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
4 * Written by Mark Salter (msalter@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public Licence as published by
8 * the Free Software Foundation; either version 2 of the Licence, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public Licence for more details.
15 *
16 * You should have received a copy of the GNU General Public Licence
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 */
20 #include <linux/kprobes.h>
21 #include <linux/ptrace.h>
22 #include <linux/spinlock.h>
23 #include <linux/preempt.h>
24 #include <linux/kdebug.h>
25 #include <asm/cacheflush.h>
26
27 struct kretprobe_blackpoint kretprobe_blacklist[] = { { NULL, NULL } };
28 const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
29
30 /* kprobe_status settings */
31 #define KPROBE_HIT_ACTIVE 0x00000001
32 #define KPROBE_HIT_SS 0x00000002
33
34 static struct kprobe *current_kprobe;
35 static unsigned long current_kprobe_orig_pc;
36 static unsigned long current_kprobe_next_pc;
37 static int current_kprobe_ss_flags;
38 static unsigned long kprobe_status;
39 static kprobe_opcode_t current_kprobe_ss_buf[MAX_INSN_SIZE + 2];
40 static unsigned long current_kprobe_bp_addr;
41
42 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
43
44
45 /* singlestep flag bits */
46 #define SINGLESTEP_BRANCH 1
47 #define SINGLESTEP_PCREL 2
48
49 #define READ_BYTE(p, valp) \
50 do { *(u8 *)(valp) = *(u8 *)(p); } while (0)
51
52 #define READ_WORD16(p, valp) \
53 do { \
54 READ_BYTE((p), (valp)); \
55 READ_BYTE((u8 *)(p) + 1, (u8 *)(valp) + 1); \
56 } while (0)
57
58 #define READ_WORD32(p, valp) \
59 do { \
60 READ_BYTE((p), (valp)); \
61 READ_BYTE((u8 *)(p) + 1, (u8 *)(valp) + 1); \
62 READ_BYTE((u8 *)(p) + 2, (u8 *)(valp) + 2); \
63 READ_BYTE((u8 *)(p) + 3, (u8 *)(valp) + 3); \
64 } while (0)
65
66
67 static const u8 mn10300_insn_sizes[256] =
68 {
69 /* 1 2 3 4 5 6 7 8 9 a b c d e f */
70 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */
71 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */
72 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */
73 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */
74 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */
75 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */
76 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */
77 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */
78 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */
79 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */
80 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */
81 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */
82 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */
83 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */
84 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */
85 0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */
86 };
87
88 #define LT (1 << 0)
89 #define GT (1 << 1)
90 #define GE (1 << 2)
91 #define LE (1 << 3)
92 #define CS (1 << 4)
93 #define HI (1 << 5)
94 #define CC (1 << 6)
95 #define LS (1 << 7)
96 #define EQ (1 << 8)
97 #define NE (1 << 9)
98 #define RA (1 << 10)
99 #define VC (1 << 11)
100 #define VS (1 << 12)
101 #define NC (1 << 13)
102 #define NS (1 << 14)
103
104 static const u16 cond_table[] = {
105 /* V C N Z */
106 /* 0 0 0 0 */ (NE | NC | CC | VC | GE | GT | HI),
107 /* 0 0 0 1 */ (EQ | NC | CC | VC | GE | LE | LS),
108 /* 0 0 1 0 */ (NE | NS | CC | VC | LT | LE | HI),
109 /* 0 0 1 1 */ (EQ | NS | CC | VC | LT | LE | LS),
110 /* 0 1 0 0 */ (NE | NC | CS | VC | GE | GT | LS),
111 /* 0 1 0 1 */ (EQ | NC | CS | VC | GE | LE | LS),
112 /* 0 1 1 0 */ (NE | NS | CS | VC | LT | LE | LS),
113 /* 0 1 1 1 */ (EQ | NS | CS | VC | LT | LE | LS),
114 /* 1 0 0 0 */ (NE | NC | CC | VS | LT | LE | HI),
115 /* 1 0 0 1 */ (EQ | NC | CC | VS | LT | LE | LS),
116 /* 1 0 1 0 */ (NE | NS | CC | VS | GE | GT | HI),
117 /* 1 0 1 1 */ (EQ | NS | CC | VS | GE | LE | LS),
118 /* 1 1 0 0 */ (NE | NC | CS | VS | LT | LE | LS),
119 /* 1 1 0 1 */ (EQ | NC | CS | VS | LT | LE | LS),
120 /* 1 1 1 0 */ (NE | NS | CS | VS | GE | GT | LS),
121 /* 1 1 1 1 */ (EQ | NS | CS | VS | GE | LE | LS),
122 };
123
124 /*
125 * Calculate what the PC will be after executing next instruction
126 */
find_nextpc(struct pt_regs * regs,int * flags)127 static unsigned find_nextpc(struct pt_regs *regs, int *flags)
128 {
129 unsigned size;
130 s8 x8;
131 s16 x16;
132 s32 x32;
133 u8 opc, *pc, *sp, *next;
134
135 next = 0;
136 *flags = SINGLESTEP_PCREL;
137
138 pc = (u8 *) regs->pc;
139 sp = (u8 *) (regs + 1);
140 opc = *pc;
141
142 size = mn10300_insn_sizes[opc];
143 if (size > 0) {
144 next = pc + size;
145 } else {
146 switch (opc) {
147 /* Bxx (d8,PC) */
148 case 0xc0 ... 0xca:
149 x8 = 2;
150 if (cond_table[regs->epsw & 0xf] & (1 << (opc & 0xf)))
151 x8 = (s8)pc[1];
152 next = pc + x8;
153 *flags |= SINGLESTEP_BRANCH;
154 break;
155
156 /* JMP (d16,PC) or CALL (d16,PC) */
157 case 0xcc:
158 case 0xcd:
159 READ_WORD16(pc + 1, &x16);
160 next = pc + x16;
161 *flags |= SINGLESTEP_BRANCH;
162 break;
163
164 /* JMP (d32,PC) or CALL (d32,PC) */
165 case 0xdc:
166 case 0xdd:
167 READ_WORD32(pc + 1, &x32);
168 next = pc + x32;
169 *flags |= SINGLESTEP_BRANCH;
170 break;
171
172 /* RETF */
173 case 0xde:
174 next = (u8 *)regs->mdr;
175 *flags &= ~SINGLESTEP_PCREL;
176 *flags |= SINGLESTEP_BRANCH;
177 break;
178
179 /* RET */
180 case 0xdf:
181 sp += pc[2];
182 READ_WORD32(sp, &x32);
183 next = (u8 *)x32;
184 *flags &= ~SINGLESTEP_PCREL;
185 *flags |= SINGLESTEP_BRANCH;
186 break;
187
188 case 0xf0:
189 next = pc + 2;
190 opc = pc[1];
191 if (opc >= 0xf0 && opc <= 0xf7) {
192 /* JMP (An) / CALLS (An) */
193 switch (opc & 3) {
194 case 0:
195 next = (u8 *)regs->a0;
196 break;
197 case 1:
198 next = (u8 *)regs->a1;
199 break;
200 case 2:
201 next = (u8 *)regs->a2;
202 break;
203 case 3:
204 next = (u8 *)regs->a3;
205 break;
206 }
207 *flags &= ~SINGLESTEP_PCREL;
208 *flags |= SINGLESTEP_BRANCH;
209 } else if (opc == 0xfc) {
210 /* RETS */
211 READ_WORD32(sp, &x32);
212 next = (u8 *)x32;
213 *flags &= ~SINGLESTEP_PCREL;
214 *flags |= SINGLESTEP_BRANCH;
215 } else if (opc == 0xfd) {
216 /* RTI */
217 READ_WORD32(sp + 4, &x32);
218 next = (u8 *)x32;
219 *flags &= ~SINGLESTEP_PCREL;
220 *flags |= SINGLESTEP_BRANCH;
221 }
222 break;
223
224 /* potential 3-byte conditional branches */
225 case 0xf8:
226 next = pc + 3;
227 opc = pc[1];
228 if (opc >= 0xe8 && opc <= 0xeb &&
229 (cond_table[regs->epsw & 0xf] &
230 (1 << ((opc & 0xf) + 3)))
231 ) {
232 READ_BYTE(pc+2, &x8);
233 next = pc + x8;
234 *flags |= SINGLESTEP_BRANCH;
235 }
236 break;
237
238 case 0xfa:
239 if (pc[1] == 0xff) {
240 /* CALLS (d16,PC) */
241 READ_WORD16(pc + 2, &x16);
242 next = pc + x16;
243 } else
244 next = pc + 4;
245 *flags |= SINGLESTEP_BRANCH;
246 break;
247
248 case 0xfc:
249 x32 = 6;
250 if (pc[1] == 0xff) {
251 /* CALLS (d32,PC) */
252 READ_WORD32(pc + 2, &x32);
253 }
254 next = pc + x32;
255 *flags |= SINGLESTEP_BRANCH;
256 break;
257 /* LXX (d8,PC) */
258 /* SETLB - loads the next four bytes into the LIR reg */
259 case 0xd0 ... 0xda:
260 case 0xdb:
261 panic("Can't singlestep Lxx/SETLB\n");
262 break;
263 }
264 }
265 return (unsigned)next;
266
267 }
268
269 /*
270 * set up out of place singlestep of some branching instructions
271 */
singlestep_branch_setup(struct pt_regs * regs)272 static unsigned __kprobes singlestep_branch_setup(struct pt_regs *regs)
273 {
274 u8 opc, *pc, *sp, *next;
275
276 next = NULL;
277 pc = (u8 *) regs->pc;
278 sp = (u8 *) (regs + 1);
279
280 switch (pc[0]) {
281 case 0xc0 ... 0xca: /* Bxx (d8,PC) */
282 case 0xcc: /* JMP (d16,PC) */
283 case 0xdc: /* JMP (d32,PC) */
284 case 0xf8: /* Bxx (d8,PC) 3-byte version */
285 /* don't really need to do anything except cause trap */
286 next = pc;
287 break;
288
289 case 0xcd: /* CALL (d16,PC) */
290 pc[1] = 5;
291 pc[2] = 0;
292 next = pc + 5;
293 break;
294
295 case 0xdd: /* CALL (d32,PC) */
296 pc[1] = 7;
297 pc[2] = 0;
298 pc[3] = 0;
299 pc[4] = 0;
300 next = pc + 7;
301 break;
302
303 case 0xde: /* RETF */
304 next = pc + 3;
305 regs->mdr = (unsigned) next;
306 break;
307
308 case 0xdf: /* RET */
309 sp += pc[2];
310 next = pc + 3;
311 *(unsigned *)sp = (unsigned) next;
312 break;
313
314 case 0xf0:
315 next = pc + 2;
316 opc = pc[1];
317 if (opc >= 0xf0 && opc <= 0xf3) {
318 /* CALLS (An) */
319 /* use CALLS (d16,PC) to avoid mucking with An */
320 pc[0] = 0xfa;
321 pc[1] = 0xff;
322 pc[2] = 4;
323 pc[3] = 0;
324 next = pc + 4;
325 } else if (opc >= 0xf4 && opc <= 0xf7) {
326 /* JMP (An) */
327 next = pc;
328 } else if (opc == 0xfc) {
329 /* RETS */
330 next = pc + 2;
331 *(unsigned *) sp = (unsigned) next;
332 } else if (opc == 0xfd) {
333 /* RTI */
334 next = pc + 2;
335 *(unsigned *)(sp + 4) = (unsigned) next;
336 }
337 break;
338
339 case 0xfa: /* CALLS (d16,PC) */
340 pc[2] = 4;
341 pc[3] = 0;
342 next = pc + 4;
343 break;
344
345 case 0xfc: /* CALLS (d32,PC) */
346 pc[2] = 6;
347 pc[3] = 0;
348 pc[4] = 0;
349 pc[5] = 0;
350 next = pc + 6;
351 break;
352
353 case 0xd0 ... 0xda: /* LXX (d8,PC) */
354 case 0xdb: /* SETLB */
355 panic("Can't singlestep Lxx/SETLB\n");
356 }
357
358 return (unsigned) next;
359 }
360
arch_prepare_kprobe(struct kprobe * p)361 int __kprobes arch_prepare_kprobe(struct kprobe *p)
362 {
363 return 0;
364 }
365
arch_copy_kprobe(struct kprobe * p)366 void __kprobes arch_copy_kprobe(struct kprobe *p)
367 {
368 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE);
369 }
370
arch_arm_kprobe(struct kprobe * p)371 void __kprobes arch_arm_kprobe(struct kprobe *p)
372 {
373 *p->addr = BREAKPOINT_INSTRUCTION;
374 flush_icache_range((unsigned long) p->addr,
375 (unsigned long) p->addr + sizeof(kprobe_opcode_t));
376 }
377
arch_disarm_kprobe(struct kprobe * p)378 void __kprobes arch_disarm_kprobe(struct kprobe *p)
379 {
380 mn10300_dcache_flush();
381 mn10300_icache_inv();
382 }
383
arch_remove_kprobe(struct kprobe * p)384 void arch_remove_kprobe(struct kprobe *p)
385 {
386 }
387
388 static inline
disarm_kprobe(struct kprobe * p,struct pt_regs * regs)389 void __kprobes disarm_kprobe(struct kprobe *p, struct pt_regs *regs)
390 {
391 *p->addr = p->opcode;
392 regs->pc = (unsigned long) p->addr;
393 mn10300_dcache_flush();
394 mn10300_icache_inv();
395 }
396
397 static inline
prepare_singlestep(struct kprobe * p,struct pt_regs * regs)398 void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
399 {
400 unsigned long nextpc;
401
402 current_kprobe_orig_pc = regs->pc;
403 memcpy(current_kprobe_ss_buf, &p->ainsn.insn[0], MAX_INSN_SIZE);
404 regs->pc = (unsigned long) current_kprobe_ss_buf;
405
406 nextpc = find_nextpc(regs, ¤t_kprobe_ss_flags);
407 if (current_kprobe_ss_flags & SINGLESTEP_PCREL)
408 current_kprobe_next_pc =
409 current_kprobe_orig_pc + (nextpc - regs->pc);
410 else
411 current_kprobe_next_pc = nextpc;
412
413 /* branching instructions need special handling */
414 if (current_kprobe_ss_flags & SINGLESTEP_BRANCH)
415 nextpc = singlestep_branch_setup(regs);
416
417 current_kprobe_bp_addr = nextpc;
418
419 *(u8 *) nextpc = BREAKPOINT_INSTRUCTION;
420 mn10300_dcache_flush_range2((unsigned) current_kprobe_ss_buf,
421 sizeof(current_kprobe_ss_buf));
422 mn10300_icache_inv();
423 }
424
kprobe_handler(struct pt_regs * regs)425 static inline int __kprobes kprobe_handler(struct pt_regs *regs)
426 {
427 struct kprobe *p;
428 int ret = 0;
429 unsigned int *addr = (unsigned int *) regs->pc;
430
431 /* We're in an interrupt, but this is clear and BUG()-safe. */
432 preempt_disable();
433
434 /* Check we're not actually recursing */
435 if (kprobe_running()) {
436 /* We *are* holding lock here, so this is safe.
437 Disarm the probe we just hit, and ignore it. */
438 p = get_kprobe(addr);
439 if (p) {
440 disarm_kprobe(p, regs);
441 ret = 1;
442 } else {
443 p = current_kprobe;
444 if (p->break_handler && p->break_handler(p, regs))
445 goto ss_probe;
446 }
447 /* If it's not ours, can't be delete race, (we hold lock). */
448 goto no_kprobe;
449 }
450
451 p = get_kprobe(addr);
452 if (!p) {
453 if (*addr != BREAKPOINT_INSTRUCTION) {
454 /* The breakpoint instruction was removed right after
455 * we hit it. Another cpu has removed either a
456 * probepoint or a debugger breakpoint at this address.
457 * In either case, no further handling of this
458 * interrupt is appropriate.
459 */
460 ret = 1;
461 }
462 /* Not one of ours: let kernel handle it */
463 goto no_kprobe;
464 }
465
466 kprobe_status = KPROBE_HIT_ACTIVE;
467 current_kprobe = p;
468 if (p->pre_handler(p, regs)) {
469 /* handler has already set things up, so skip ss setup */
470 return 1;
471 }
472
473 ss_probe:
474 prepare_singlestep(p, regs);
475 kprobe_status = KPROBE_HIT_SS;
476 return 1;
477
478 no_kprobe:
479 preempt_enable_no_resched();
480 return ret;
481 }
482
483 /*
484 * Called after single-stepping. p->addr is the address of the
485 * instruction whose first byte has been replaced by the "breakpoint"
486 * instruction. To avoid the SMP problems that can occur when we
487 * temporarily put back the original opcode to single-step, we
488 * single-stepped a copy of the instruction. The address of this
489 * copy is p->ainsn.insn.
490 */
resume_execution(struct kprobe * p,struct pt_regs * regs)491 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
492 {
493 /* we may need to fixup regs/stack after singlestepping a call insn */
494 if (current_kprobe_ss_flags & SINGLESTEP_BRANCH) {
495 regs->pc = current_kprobe_orig_pc;
496 switch (p->ainsn.insn[0]) {
497 case 0xcd: /* CALL (d16,PC) */
498 *(unsigned *) regs->sp = regs->mdr = regs->pc + 5;
499 break;
500 case 0xdd: /* CALL (d32,PC) */
501 /* fixup mdr and return address on stack */
502 *(unsigned *) regs->sp = regs->mdr = regs->pc + 7;
503 break;
504 case 0xf0:
505 if (p->ainsn.insn[1] >= 0xf0 &&
506 p->ainsn.insn[1] <= 0xf3) {
507 /* CALLS (An) */
508 /* fixup MDR and return address on stack */
509 regs->mdr = regs->pc + 2;
510 *(unsigned *) regs->sp = regs->mdr;
511 }
512 break;
513
514 case 0xfa: /* CALLS (d16,PC) */
515 /* fixup MDR and return address on stack */
516 *(unsigned *) regs->sp = regs->mdr = regs->pc + 4;
517 break;
518
519 case 0xfc: /* CALLS (d32,PC) */
520 /* fixup MDR and return address on stack */
521 *(unsigned *) regs->sp = regs->mdr = regs->pc + 6;
522 break;
523 }
524 }
525
526 regs->pc = current_kprobe_next_pc;
527 current_kprobe_bp_addr = 0;
528 }
529
post_kprobe_handler(struct pt_regs * regs)530 static inline int __kprobes post_kprobe_handler(struct pt_regs *regs)
531 {
532 if (!kprobe_running())
533 return 0;
534
535 if (current_kprobe->post_handler)
536 current_kprobe->post_handler(current_kprobe, regs, 0);
537
538 resume_execution(current_kprobe, regs);
539 reset_current_kprobe();
540 preempt_enable_no_resched();
541 return 1;
542 }
543
544 /* Interrupts disabled, kprobe_lock held. */
545 static inline
kprobe_fault_handler(struct pt_regs * regs,int trapnr)546 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
547 {
548 if (current_kprobe->fault_handler &&
549 current_kprobe->fault_handler(current_kprobe, regs, trapnr))
550 return 1;
551
552 if (kprobe_status & KPROBE_HIT_SS) {
553 resume_execution(current_kprobe, regs);
554 reset_current_kprobe();
555 preempt_enable_no_resched();
556 }
557 return 0;
558 }
559
560 /*
561 * Wrapper routine to for handling exceptions.
562 */
kprobe_exceptions_notify(struct notifier_block * self,unsigned long val,void * data)563 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
564 unsigned long val, void *data)
565 {
566 struct die_args *args = data;
567
568 switch (val) {
569 case DIE_BREAKPOINT:
570 if (current_kprobe_bp_addr != args->regs->pc) {
571 if (kprobe_handler(args->regs))
572 return NOTIFY_STOP;
573 } else {
574 if (post_kprobe_handler(args->regs))
575 return NOTIFY_STOP;
576 }
577 break;
578 case DIE_GPF:
579 if (kprobe_running() &&
580 kprobe_fault_handler(args->regs, args->trapnr))
581 return NOTIFY_STOP;
582 break;
583 default:
584 break;
585 }
586 return NOTIFY_DONE;
587 }
588
589 /* Jprobes support. */
590 static struct pt_regs jprobe_saved_regs;
591 static struct pt_regs *jprobe_saved_regs_location;
592 static kprobe_opcode_t jprobe_saved_stack[MAX_STACK_SIZE];
593
setjmp_pre_handler(struct kprobe * p,struct pt_regs * regs)594 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
595 {
596 struct jprobe *jp = container_of(p, struct jprobe, kp);
597
598 jprobe_saved_regs_location = regs;
599 memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs));
600
601 /* Save a whole stack frame, this gets arguments
602 * pushed onto the stack after using up all the
603 * arg registers.
604 */
605 memcpy(&jprobe_saved_stack, regs + 1, sizeof(jprobe_saved_stack));
606
607 /* setup return addr to the jprobe handler routine */
608 regs->pc = (unsigned long) jp->entry;
609 return 1;
610 }
611
jprobe_return(void)612 void __kprobes jprobe_return(void)
613 {
614 void *orig_sp = jprobe_saved_regs_location + 1;
615
616 preempt_enable_no_resched();
617 asm volatile(" mov %0,sp\n"
618 ".globl jprobe_return_bp_addr\n"
619 "jprobe_return_bp_addr:\n\t"
620 " .byte 0xff\n"
621 : : "d" (orig_sp));
622 }
623
624 extern void jprobe_return_bp_addr(void);
625
longjmp_break_handler(struct kprobe * p,struct pt_regs * regs)626 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
627 {
628 u8 *addr = (u8 *) regs->pc;
629
630 if (addr == (u8 *) jprobe_return_bp_addr) {
631 if (jprobe_saved_regs_location != regs) {
632 printk(KERN_ERR"JPROBE:"
633 " Current regs (%p) does not match saved regs"
634 " (%p).\n",
635 regs, jprobe_saved_regs_location);
636 BUG();
637 }
638
639 /* Restore old register state.
640 */
641 memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs));
642
643 memcpy(regs + 1, &jprobe_saved_stack,
644 sizeof(jprobe_saved_stack));
645 return 1;
646 }
647 return 0;
648 }
649
arch_init_kprobes(void)650 int __init arch_init_kprobes(void)
651 {
652 return 0;
653 }
654