[PATCH] Kprobes: prevent possible race conditions ia64 changes
[linux-2.6.git] / arch / ia64 / kernel / kprobes.c
1 /*
2  *  Kernel Probes (KProbes)
3  *  arch/ia64/kernel/kprobes.c
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18  *
19  * Copyright (C) IBM Corporation, 2002, 2004
20  * Copyright (C) Intel Corporation, 2005
21  *
22  * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
23  *              <anil.s.keshavamurthy@intel.com> adapted from i386
24  */
25
26 #include <linux/config.h>
27 #include <linux/kprobes.h>
28 #include <linux/ptrace.h>
29 #include <linux/spinlock.h>
30 #include <linux/string.h>
31 #include <linux/slab.h>
32 #include <linux/preempt.h>
33 #include <linux/moduleloader.h>
34
35 #include <asm/pgtable.h>
36 #include <asm/kdebug.h>
37 #include <asm/sections.h>
38
39 extern void jprobe_inst_return(void);
40
41 /* kprobe_status settings */
42 #define KPROBE_HIT_ACTIVE       0x00000001
43 #define KPROBE_HIT_SS           0x00000002
44
45 static struct kprobe *current_kprobe, *kprobe_prev;
46 static unsigned long kprobe_status, kprobe_status_prev;
47 static struct pt_regs jprobe_saved_regs;
48
49 enum instruction_type {A, I, M, F, B, L, X, u};
50 static enum instruction_type bundle_encoding[32][3] = {
51   { M, I, I },                          /* 00 */
52   { M, I, I },                          /* 01 */
53   { M, I, I },                          /* 02 */
54   { M, I, I },                          /* 03 */
55   { M, L, X },                          /* 04 */
56   { M, L, X },                          /* 05 */
57   { u, u, u },                          /* 06 */
58   { u, u, u },                          /* 07 */
59   { M, M, I },                          /* 08 */
60   { M, M, I },                          /* 09 */
61   { M, M, I },                          /* 0A */
62   { M, M, I },                          /* 0B */
63   { M, F, I },                          /* 0C */
64   { M, F, I },                          /* 0D */
65   { M, M, F },                          /* 0E */
66   { M, M, F },                          /* 0F */
67   { M, I, B },                          /* 10 */
68   { M, I, B },                          /* 11 */
69   { M, B, B },                          /* 12 */
70   { M, B, B },                          /* 13 */
71   { u, u, u },                          /* 14 */
72   { u, u, u },                          /* 15 */
73   { B, B, B },                          /* 16 */
74   { B, B, B },                          /* 17 */
75   { M, M, B },                          /* 18 */
76   { M, M, B },                          /* 19 */
77   { u, u, u },                          /* 1A */
78   { u, u, u },                          /* 1B */
79   { M, F, B },                          /* 1C */
80   { M, F, B },                          /* 1D */
81   { u, u, u },                          /* 1E */
82   { u, u, u },                          /* 1F */
83 };
84
85 /*
86  * In this function we check to see if the instruction
87  * is IP relative instruction and update the kprobe
88  * inst flag accordingly
89  */
90 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
91                                               uint major_opcode,
92                                               unsigned long kprobe_inst,
93                                               struct kprobe *p)
94 {
95         p->ainsn.inst_flag = 0;
96         p->ainsn.target_br_reg = 0;
97
98         if (bundle_encoding[template][slot] == B) {
99                 switch (major_opcode) {
100                   case INDIRECT_CALL_OPCODE:
101                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
102                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
103                         break;
104                   case IP_RELATIVE_PREDICT_OPCODE:
105                   case IP_RELATIVE_BRANCH_OPCODE:
106                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
107                         break;
108                   case IP_RELATIVE_CALL_OPCODE:
109                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
110                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
111                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
112                         break;
113                 }
114         } else if (bundle_encoding[template][slot] == X) {
115                 switch (major_opcode) {
116                   case LONG_CALL_OPCODE:
117                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
118                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
119                   break;
120                 }
121         }
122         return;
123 }
124
125 /*
126  * In this function we check to see if the instruction
127  * on which we are inserting kprobe is supported.
128  * Returns 0 if supported
129  * Returns -EINVAL if unsupported
130  */
131 static int __kprobes unsupported_inst(uint template, uint  slot,
132                                       uint major_opcode,
133                                       unsigned long kprobe_inst,
134                                       struct kprobe *p)
135 {
136         unsigned long addr = (unsigned long)p->addr;
137
138         if (bundle_encoding[template][slot] == I) {
139                 switch (major_opcode) {
140                         case 0x0: //I_UNIT_MISC_OPCODE:
141                         /*
142                          * Check for Integer speculation instruction
143                          * - Bit 33-35 to be equal to 0x1
144                          */
145                         if (((kprobe_inst >> 33) & 0x7) == 1) {
146                                 printk(KERN_WARNING
147                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
148                                         addr);
149                                 return -EINVAL;
150                         }
151
152                         /*
153                          * IP relative mov instruction
154                          *  - Bit 27-35 to be equal to 0x30
155                          */
156                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
157                                 printk(KERN_WARNING
158                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
159                                         addr);
160                                 return -EINVAL;
161
162                         }
163                 }
164         }
165         return 0;
166 }
167
168
169 /*
170  * In this function we check to see if the instruction
171  * (qp) cmpx.crel.ctype p1,p2=r2,r3
172  * on which we are inserting kprobe is cmp instruction
173  * with ctype as unc.
174  */
175 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
176                                             uint major_opcode,
177                                             unsigned long kprobe_inst)
178 {
179         cmp_inst_t cmp_inst;
180         uint ctype_unc = 0;
181
182         if (!((bundle_encoding[template][slot] == I) ||
183                 (bundle_encoding[template][slot] == M)))
184                 goto out;
185
186         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
187                 (major_opcode == 0xE)))
188                 goto out;
189
190         cmp_inst.l = kprobe_inst;
191         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
192                 /* Integere compare - Register Register (A6 type)*/
193                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
194                                 &&(cmp_inst.f.c == 1))
195                         ctype_unc = 1;
196         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
197                 /* Integere compare - Immediate Register (A8 type)*/
198                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
199                         ctype_unc = 1;
200         }
201 out:
202         return ctype_unc;
203 }
204
205 /*
206  * In this function we override the bundle with
207  * the break instruction at the given slot.
208  */
209 static void __kprobes prepare_break_inst(uint template, uint  slot,
210                                          uint major_opcode,
211                                          unsigned long kprobe_inst,
212                                          struct kprobe *p)
213 {
214         unsigned long break_inst = BREAK_INST;
215         bundle_t *bundle = &p->ainsn.insn.bundle;
216
217         /*
218          * Copy the original kprobe_inst qualifying predicate(qp)
219          * to the break instruction iff !is_cmp_ctype_unc_inst
220          * because for cmp instruction with ctype equal to unc,
221          * which is a special instruction always needs to be
222          * executed regradless of qp
223          */
224         if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
225                 break_inst |= (0x3f & kprobe_inst);
226
227         switch (slot) {
228           case 0:
229                 bundle->quad0.slot0 = break_inst;
230                 break;
231           case 1:
232                 bundle->quad0.slot1_p0 = break_inst;
233                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
234                 break;
235           case 2:
236                 bundle->quad1.slot2 = break_inst;
237                 break;
238         }
239
240         /*
241          * Update the instruction flag, so that we can
242          * emulate the instruction properly after we
243          * single step on original instruction
244          */
245         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
246 }
247
248 static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
249                 unsigned long *kprobe_inst, uint *major_opcode)
250 {
251         unsigned long kprobe_inst_p0, kprobe_inst_p1;
252         unsigned int template;
253
254         template = bundle->quad0.template;
255
256         switch (slot) {
257           case 0:
258                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
259                 *kprobe_inst = bundle->quad0.slot0;
260                 break;
261           case 1:
262                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
263                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
264                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
265                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
266                 break;
267           case 2:
268                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
269                 *kprobe_inst = bundle->quad1.slot2;
270                 break;
271         }
272 }
273
274 /* Returns non-zero if the addr is in the Interrupt Vector Table */
275 static inline int in_ivt_functions(unsigned long addr)
276 {
277         return (addr >= (unsigned long)__start_ivt_text
278                 && addr < (unsigned long)__end_ivt_text);
279 }
280
281 static int __kprobes valid_kprobe_addr(int template, int slot,
282                                        unsigned long addr)
283 {
284         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
285                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
286                                 "at 0x%lx\n", addr);
287                 return -EINVAL;
288         }
289
290         if (in_ivt_functions(addr)) {
291                 printk(KERN_WARNING "Kprobes can't be inserted inside "
292                                 "IVT functions at 0x%lx\n", addr);
293                 return -EINVAL;
294         }
295
296         if (slot == 1 && bundle_encoding[template][1] != L) {
297                 printk(KERN_WARNING "Inserting kprobes on slot #1 "
298                        "is not supported\n");
299                 return -EINVAL;
300         }
301
302         return 0;
303 }
304
305 static inline void save_previous_kprobe(void)
306 {
307         kprobe_prev = current_kprobe;
308         kprobe_status_prev = kprobe_status;
309 }
310
311 static inline void restore_previous_kprobe(void)
312 {
313         current_kprobe = kprobe_prev;
314         kprobe_status = kprobe_status_prev;
315 }
316
317 static inline void set_current_kprobe(struct kprobe *p)
318 {
319         current_kprobe = p;
320 }
321
322 static void kretprobe_trampoline(void)
323 {
324 }
325
326 /*
327  * At this point the target function has been tricked into
328  * returning into our trampoline.  Lookup the associated instance
329  * and then:
330  *    - call the handler function
331  *    - cleanup by marking the instance as unused
332  *    - long jump back to the original return address
333  */
334 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
335 {
336         struct kretprobe_instance *ri = NULL;
337         struct hlist_head *head;
338         struct hlist_node *node, *tmp;
339         unsigned long orig_ret_address = 0;
340         unsigned long trampoline_address =
341                 ((struct fnptr *)kretprobe_trampoline)->ip;
342
343         head = kretprobe_inst_table_head(current);
344
345         /*
346          * It is possible to have multiple instances associated with a given
347          * task either because an multiple functions in the call path
348          * have a return probe installed on them, and/or more then one return
349          * return probe was registered for a target function.
350          *
351          * We can handle this because:
352          *     - instances are always inserted at the head of the list
353          *     - when multiple return probes are registered for the same
354          *       function, the first instance's ret_addr will point to the
355          *       real return address, and all the rest will point to
356          *       kretprobe_trampoline
357          */
358         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
359                 if (ri->task != current)
360                         /* another task is sharing our hash bucket */
361                         continue;
362
363                 if (ri->rp && ri->rp->handler)
364                         ri->rp->handler(ri, regs);
365
366                 orig_ret_address = (unsigned long)ri->ret_addr;
367                 recycle_rp_inst(ri);
368
369                 if (orig_ret_address != trampoline_address)
370                         /*
371                          * This is the real return address. Any other
372                          * instances associated with this task are for
373                          * other calls deeper on the call stack
374                          */
375                         break;
376         }
377
378         BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
379         regs->cr_iip = orig_ret_address;
380
381         unlock_kprobes();
382         preempt_enable_no_resched();
383
384         /*
385          * By returning a non-zero value, we are telling
386          * kprobe_handler() that we have handled unlocking
387          * and re-enabling preemption.
388          */
389         return 1;
390 }
391
392 void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
393                                       struct pt_regs *regs)
394 {
395         struct kretprobe_instance *ri;
396
397         if ((ri = get_free_rp_inst(rp)) != NULL) {
398                 ri->rp = rp;
399                 ri->task = current;
400                 ri->ret_addr = (kprobe_opcode_t *)regs->b0;
401
402                 /* Replace the return addr with trampoline addr */
403                 regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
404
405                 add_rp_inst(ri);
406         } else {
407                 rp->nmissed++;
408         }
409 }
410
411 int __kprobes arch_prepare_kprobe(struct kprobe *p)
412 {
413         unsigned long addr = (unsigned long) p->addr;
414         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
415         unsigned long kprobe_inst=0;
416         unsigned int slot = addr & 0xf, template, major_opcode = 0;
417         bundle_t *bundle = &p->ainsn.insn.bundle;
418
419         memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
420         memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));
421
422         template = bundle->quad0.template;
423
424         if(valid_kprobe_addr(template, slot, addr))
425                 return -EINVAL;
426
427         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
428         if (slot == 1 && bundle_encoding[template][1] == L)
429                 slot++;
430
431         /* Get kprobe_inst and major_opcode from the bundle */
432         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
433
434         if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
435                         return -EINVAL;
436
437         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
438
439         return 0;
440 }
441
442 void __kprobes arch_arm_kprobe(struct kprobe *p)
443 {
444         unsigned long addr = (unsigned long)p->addr;
445         unsigned long arm_addr = addr & ~0xFULL;
446
447         memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
448         flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
449 }
450
451 void __kprobes arch_disarm_kprobe(struct kprobe *p)
452 {
453         unsigned long addr = (unsigned long)p->addr;
454         unsigned long arm_addr = addr & ~0xFULL;
455
456         /* p->opcode contains the original unaltered bundle */
457         memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t));
458         flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
459 }
460
461 void __kprobes arch_remove_kprobe(struct kprobe *p)
462 {
463 }
464
465 /*
466  * We are resuming execution after a single step fault, so the pt_regs
467  * structure reflects the register state after we executed the instruction
468  * located in the kprobe (p->ainsn.insn.bundle).  We still need to adjust
469  * the ip to point back to the original stack address. To set the IP address
470  * to original stack address, handle the case where we need to fixup the
471  * relative IP address and/or fixup branch register.
472  */
473 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
474 {
475         unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
476         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
477         unsigned long template;
478         int slot = ((unsigned long)p->addr & 0xf);
479
480         template = p->opcode.bundle.quad0.template;
481
482         if (slot == 1 && bundle_encoding[template][1] == L)
483                 slot = 2;
484
485         if (p->ainsn.inst_flag) {
486
487                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
488                         /* Fix relative IP address */
489                         regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
490                 }
491
492                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
493                 /*
494                  * Fix target branch register, software convention is
495                  * to use either b0 or b6 or b7, so just checking
496                  * only those registers
497                  */
498                         switch (p->ainsn.target_br_reg) {
499                         case 0:
500                                 if ((regs->b0 == bundle_addr) ||
501                                         (regs->b0 == bundle_addr + 0x10)) {
502                                         regs->b0 = (regs->b0 - bundle_addr) +
503                                                 resume_addr;
504                                 }
505                                 break;
506                         case 6:
507                                 if ((regs->b6 == bundle_addr) ||
508                                         (regs->b6 == bundle_addr + 0x10)) {
509                                         regs->b6 = (regs->b6 - bundle_addr) +
510                                                 resume_addr;
511                                 }
512                                 break;
513                         case 7:
514                                 if ((regs->b7 == bundle_addr) ||
515                                         (regs->b7 == bundle_addr + 0x10)) {
516                                         regs->b7 = (regs->b7 - bundle_addr) +
517                                                 resume_addr;
518                                 }
519                                 break;
520                         } /* end switch */
521                 }
522                 goto turn_ss_off;
523         }
524
525         if (slot == 2) {
526                 if (regs->cr_iip == bundle_addr + 0x10) {
527                         regs->cr_iip = resume_addr + 0x10;
528                 }
529         } else {
530                 if (regs->cr_iip == bundle_addr) {
531                         regs->cr_iip = resume_addr;
532                 }
533         }
534
535 turn_ss_off:
536         /* Turn off Single Step bit */
537         ia64_psr(regs)->ss = 0;
538 }
539
540 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
541 {
542         unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
543         unsigned long slot = (unsigned long)p->addr & 0xf;
544
545         /* Update instruction pointer (IIP) and slot number (IPSR.ri) */
546         regs->cr_iip = bundle_addr & ~0xFULL;
547
548         if (slot > 2)
549                 slot = 0;
550
551         ia64_psr(regs)->ri = slot;
552
553         /* turn on single stepping */
554         ia64_psr(regs)->ss = 1;
555 }
556
557 static int __kprobes pre_kprobes_handler(struct die_args *args)
558 {
559         struct kprobe *p;
560         int ret = 0;
561         struct pt_regs *regs = args->regs;
562         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
563
564         preempt_disable();
565
566         /* Handle recursion cases */
567         if (kprobe_running()) {
568                 p = get_kprobe(addr);
569                 if (p) {
570                         if (kprobe_status == KPROBE_HIT_SS) {
571                                 unlock_kprobes();
572                                 goto no_kprobe;
573                         }
574                         /* We have reentered the pre_kprobe_handler(), since
575                          * another probe was hit while within the handler.
576                          * We here save the original kprobes variables and
577                          * just single step on the instruction of the new probe
578                          * without calling any user handlers.
579                          */
580                         save_previous_kprobe();
581                         set_current_kprobe(p);
582                         p->nmissed++;
583                         prepare_ss(p, regs);
584                         kprobe_status = KPROBE_REENTER;
585                         return 1;
586                 } else if (args->err == __IA64_BREAK_JPROBE) {
587                         /*
588                          * jprobe instrumented function just completed
589                          */
590                         p = current_kprobe;
591                         if (p->break_handler && p->break_handler(p, regs)) {
592                                 goto ss_probe;
593                         }
594                 } else {
595                         /* Not our break */
596                         goto no_kprobe;
597                 }
598         }
599
600         lock_kprobes();
601         p = get_kprobe(addr);
602         if (!p) {
603                 unlock_kprobes();
604                 goto no_kprobe;
605         }
606
607         kprobe_status = KPROBE_HIT_ACTIVE;
608         set_current_kprobe(p);
609
610         if (p->pre_handler && p->pre_handler(p, regs))
611                 /*
612                  * Our pre-handler is specifically requesting that we just
613                  * do a return.  This is used for both the jprobe pre-handler
614                  * and the kretprobe trampoline
615                  */
616                 return 1;
617
618 ss_probe:
619         prepare_ss(p, regs);
620         kprobe_status = KPROBE_HIT_SS;
621         return 1;
622
623 no_kprobe:
624         preempt_enable_no_resched();
625         return ret;
626 }
627
628 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
629 {
630         if (!kprobe_running())
631                 return 0;
632
633         if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
634                 kprobe_status = KPROBE_HIT_SSDONE;
635                 current_kprobe->post_handler(current_kprobe, regs, 0);
636         }
637
638         resume_execution(current_kprobe, regs);
639
640         /*Restore back the original saved kprobes variables and continue. */
641         if (kprobe_status == KPROBE_REENTER) {
642                 restore_previous_kprobe();
643                 goto out;
644         }
645
646         unlock_kprobes();
647
648 out:
649         preempt_enable_no_resched();
650         return 1;
651 }
652
653 static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
654 {
655         if (!kprobe_running())
656                 return 0;
657
658         if (current_kprobe->fault_handler &&
659             current_kprobe->fault_handler(current_kprobe, regs, trapnr))
660                 return 1;
661
662         if (kprobe_status & KPROBE_HIT_SS) {
663                 resume_execution(current_kprobe, regs);
664                 unlock_kprobes();
665                 preempt_enable_no_resched();
666         }
667
668         return 0;
669 }
670
671 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
672                                        unsigned long val, void *data)
673 {
674         struct die_args *args = (struct die_args *)data;
675         switch(val) {
676         case DIE_BREAK:
677                 if (pre_kprobes_handler(args))
678                         return NOTIFY_STOP;
679                 break;
680         case DIE_SS:
681                 if (post_kprobes_handler(args->regs))
682                         return NOTIFY_STOP;
683                 break;
684         case DIE_PAGE_FAULT:
685                 if (kprobes_fault_handler(args->regs, args->trapnr))
686                         return NOTIFY_STOP;
687         default:
688                 break;
689         }
690         return NOTIFY_DONE;
691 }
692
693 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
694 {
695         struct jprobe *jp = container_of(p, struct jprobe, kp);
696         unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
697
698         /* save architectural state */
699         jprobe_saved_regs = *regs;
700
701         /* after rfi, execute the jprobe instrumented function */
702         regs->cr_iip = addr & ~0xFULL;
703         ia64_psr(regs)->ri = addr & 0xf;
704         regs->r1 = ((struct fnptr *)(jp->entry))->gp;
705
706         /*
707          * fix the return address to our jprobe_inst_return() function
708          * in the jprobes.S file
709          */
710         regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
711
712         return 1;
713 }
714
715 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
716 {
717         *regs = jprobe_saved_regs;
718         return 1;
719 }
720
721 static struct kprobe trampoline_p = {
722         .pre_handler = trampoline_probe_handler
723 };
724
725 int __init arch_init_kprobes(void)
726 {
727         trampoline_p.addr =
728                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
729         return register_kprobe(&trampoline_p);
730 }