kprobes: support kretprobe blacklist
[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/kprobes.h>
27 #include <linux/ptrace.h>
28 #include <linux/string.h>
29 #include <linux/slab.h>
30 #include <linux/preempt.h>
31 #include <linux/moduleloader.h>
32 #include <linux/kdebug.h>
33
34 #include <asm/pgtable.h>
35 #include <asm/sections.h>
36 #include <asm/uaccess.h>
37
38 extern void jprobe_inst_return(void);
39
40 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
41 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
42
43 struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
44
45 enum instruction_type {A, I, M, F, B, L, X, u};
46 static enum instruction_type bundle_encoding[32][3] = {
47   { M, I, I },                          /* 00 */
48   { M, I, I },                          /* 01 */
49   { M, I, I },                          /* 02 */
50   { M, I, I },                          /* 03 */
51   { M, L, X },                          /* 04 */
52   { M, L, X },                          /* 05 */
53   { u, u, u },                          /* 06 */
54   { u, u, u },                          /* 07 */
55   { M, M, I },                          /* 08 */
56   { M, M, I },                          /* 09 */
57   { M, M, I },                          /* 0A */
58   { M, M, I },                          /* 0B */
59   { M, F, I },                          /* 0C */
60   { M, F, I },                          /* 0D */
61   { M, M, F },                          /* 0E */
62   { M, M, F },                          /* 0F */
63   { M, I, B },                          /* 10 */
64   { M, I, B },                          /* 11 */
65   { M, B, B },                          /* 12 */
66   { M, B, B },                          /* 13 */
67   { u, u, u },                          /* 14 */
68   { u, u, u },                          /* 15 */
69   { B, B, B },                          /* 16 */
70   { B, B, B },                          /* 17 */
71   { M, M, B },                          /* 18 */
72   { M, M, B },                          /* 19 */
73   { u, u, u },                          /* 1A */
74   { u, u, u },                          /* 1B */
75   { M, F, B },                          /* 1C */
76   { M, F, B },                          /* 1D */
77   { u, u, u },                          /* 1E */
78   { u, u, u },                          /* 1F */
79 };
80
81 /*
82  * In this function we check to see if the instruction
83  * is IP relative instruction and update the kprobe
84  * inst flag accordingly
85  */
86 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
87                                               uint major_opcode,
88                                               unsigned long kprobe_inst,
89                                               struct kprobe *p)
90 {
91         p->ainsn.inst_flag = 0;
92         p->ainsn.target_br_reg = 0;
93         p->ainsn.slot = slot;
94
95         /* Check for Break instruction
96          * Bits 37:40 Major opcode to be zero
97          * Bits 27:32 X6 to be zero
98          * Bits 32:35 X3 to be zero
99          */
100         if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
101                 /* is a break instruction */
102                 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
103                 return;
104         }
105
106         if (bundle_encoding[template][slot] == B) {
107                 switch (major_opcode) {
108                   case INDIRECT_CALL_OPCODE:
109                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
110                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
111                         break;
112                   case IP_RELATIVE_PREDICT_OPCODE:
113                   case IP_RELATIVE_BRANCH_OPCODE:
114                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
115                         break;
116                   case IP_RELATIVE_CALL_OPCODE:
117                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
118                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
119                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
120                         break;
121                 }
122         } else if (bundle_encoding[template][slot] == X) {
123                 switch (major_opcode) {
124                   case LONG_CALL_OPCODE:
125                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
126                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
127                   break;
128                 }
129         }
130         return;
131 }
132
133 /*
134  * In this function we check to see if the instruction
135  * (qp) cmpx.crel.ctype p1,p2=r2,r3
136  * on which we are inserting kprobe is cmp instruction
137  * with ctype as unc.
138  */
139 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
140                                             uint major_opcode,
141                                             unsigned long kprobe_inst)
142 {
143         cmp_inst_t cmp_inst;
144         uint ctype_unc = 0;
145
146         if (!((bundle_encoding[template][slot] == I) ||
147                 (bundle_encoding[template][slot] == M)))
148                 goto out;
149
150         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
151                 (major_opcode == 0xE)))
152                 goto out;
153
154         cmp_inst.l = kprobe_inst;
155         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
156                 /* Integer compare - Register Register (A6 type)*/
157                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
158                                 &&(cmp_inst.f.c == 1))
159                         ctype_unc = 1;
160         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
161                 /* Integer compare - Immediate Register (A8 type)*/
162                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
163                         ctype_unc = 1;
164         }
165 out:
166         return ctype_unc;
167 }
168
169 /*
170  * In this function we check to see if the instruction
171  * on which we are inserting kprobe is supported.
172  * Returns qp value if supported
173  * Returns -EINVAL if unsupported
174  */
175 static int __kprobes unsupported_inst(uint template, uint  slot,
176                                       uint major_opcode,
177                                       unsigned long kprobe_inst,
178                                       unsigned long addr)
179 {
180         int qp;
181
182         qp = kprobe_inst & 0x3f;
183         if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
184                 if (slot == 1 && qp)  {
185                         printk(KERN_WARNING "Kprobes on cmp unc"
186                                         "instruction on slot 1 at <0x%lx>"
187                                         "is not supported\n", addr);
188                         return -EINVAL;
189
190                 }
191                 qp = 0;
192         }
193         else if (bundle_encoding[template][slot] == I) {
194                 if (major_opcode == 0) {
195                         /*
196                          * Check for Integer speculation instruction
197                          * - Bit 33-35 to be equal to 0x1
198                          */
199                         if (((kprobe_inst >> 33) & 0x7) == 1) {
200                                 printk(KERN_WARNING
201                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
202                                                 addr);
203                                 return -EINVAL;
204                         }
205                         /*
206                          * IP relative mov instruction
207                          *  - Bit 27-35 to be equal to 0x30
208                          */
209                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
210                                 printk(KERN_WARNING
211                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
212                                                 addr);
213                                 return -EINVAL;
214
215                         }
216                 }
217                 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
218                                 (kprobe_inst & (0x1UL << 12))) {
219                         /* test bit instructions, tbit,tnat,tf
220                          * bit 33-36 to be equal to 0
221                          * bit 12 to be equal to 1
222                          */
223                         if (slot == 1 && qp) {
224                                 printk(KERN_WARNING "Kprobes on test bit"
225                                                 "instruction on slot at <0x%lx>"
226                                                 "is not supported\n", addr);
227                                 return -EINVAL;
228                         }
229                         qp = 0;
230                 }
231         }
232         else if (bundle_encoding[template][slot] == B) {
233                 if (major_opcode == 7) {
234                         /* IP-Relative Predict major code is 7 */
235                         printk(KERN_WARNING "Kprobes on IP-Relative"
236                                         "Predict is not supported\n");
237                         return -EINVAL;
238                 }
239                 else if (major_opcode == 2) {
240                         /* Indirect Predict, major code is 2
241                          * bit 27-32 to be equal to 10 or 11
242                          */
243                         int x6=(kprobe_inst >> 27) & 0x3F;
244                         if ((x6 == 0x10) || (x6 == 0x11)) {
245                                 printk(KERN_WARNING "Kprobes on"
246                                         "Indirect Predict is not supported\n");
247                                 return -EINVAL;
248                         }
249                 }
250         }
251         /* kernel does not use float instruction, here for safety kprobe
252          * will judge whether it is fcmp/flass/float approximation instruction
253          */
254         else if (unlikely(bundle_encoding[template][slot] == F)) {
255                 if ((major_opcode == 4 || major_opcode == 5) &&
256                                 (kprobe_inst  & (0x1 << 12))) {
257                         /* fcmp/fclass unc instruction */
258                         if (slot == 1 && qp) {
259                                 printk(KERN_WARNING "Kprobes on fcmp/fclass "
260                                         "instruction on slot at <0x%lx> "
261                                         "is not supported\n", addr);
262                                 return -EINVAL;
263
264                         }
265                         qp = 0;
266                 }
267                 if ((major_opcode == 0 || major_opcode == 1) &&
268                         (kprobe_inst & (0x1UL << 33))) {
269                         /* float Approximation instruction */
270                         if (slot == 1 && qp) {
271                                 printk(KERN_WARNING "Kprobes on float Approx "
272                                         "instr at <0x%lx> is not supported\n",
273                                                 addr);
274                                 return -EINVAL;
275                         }
276                         qp = 0;
277                 }
278         }
279         return qp;
280 }
281
282 /*
283  * In this function we override the bundle with
284  * the break instruction at the given slot.
285  */
286 static void __kprobes prepare_break_inst(uint template, uint  slot,
287                                          uint major_opcode,
288                                          unsigned long kprobe_inst,
289                                          struct kprobe *p,
290                                          int qp)
291 {
292         unsigned long break_inst = BREAK_INST;
293         bundle_t *bundle = &p->opcode.bundle;
294
295         /*
296          * Copy the original kprobe_inst qualifying predicate(qp)
297          * to the break instruction
298          */
299         break_inst |= qp;
300
301         switch (slot) {
302           case 0:
303                 bundle->quad0.slot0 = break_inst;
304                 break;
305           case 1:
306                 bundle->quad0.slot1_p0 = break_inst;
307                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
308                 break;
309           case 2:
310                 bundle->quad1.slot2 = break_inst;
311                 break;
312         }
313
314         /*
315          * Update the instruction flag, so that we can
316          * emulate the instruction properly after we
317          * single step on original instruction
318          */
319         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
320 }
321
322 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
323                 unsigned long *kprobe_inst, uint *major_opcode)
324 {
325         unsigned long kprobe_inst_p0, kprobe_inst_p1;
326         unsigned int template;
327
328         template = bundle->quad0.template;
329
330         switch (slot) {
331           case 0:
332                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
333                 *kprobe_inst = bundle->quad0.slot0;
334                   break;
335           case 1:
336                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
337                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
338                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
339                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
340                 break;
341           case 2:
342                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
343                 *kprobe_inst = bundle->quad1.slot2;
344                 break;
345         }
346 }
347
348 /* Returns non-zero if the addr is in the Interrupt Vector Table */
349 static int __kprobes in_ivt_functions(unsigned long addr)
350 {
351         return (addr >= (unsigned long)__start_ivt_text
352                 && addr < (unsigned long)__end_ivt_text);
353 }
354
355 static int __kprobes valid_kprobe_addr(int template, int slot,
356                                        unsigned long addr)
357 {
358         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
359                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
360                                 "at 0x%lx\n", addr);
361                 return -EINVAL;
362         }
363
364         if (in_ivt_functions(addr)) {
365                 printk(KERN_WARNING "Kprobes can't be inserted inside "
366                                 "IVT functions at 0x%lx\n", addr);
367                 return -EINVAL;
368         }
369
370         return 0;
371 }
372
373 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
374 {
375         unsigned int i;
376         i = atomic_add_return(1, &kcb->prev_kprobe_index);
377         kcb->prev_kprobe[i-1].kp = kprobe_running();
378         kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
379 }
380
381 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
382 {
383         unsigned int i;
384         i = atomic_sub_return(1, &kcb->prev_kprobe_index);
385         __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i].kp;
386         kcb->kprobe_status = kcb->prev_kprobe[i].status;
387 }
388
389 static void __kprobes set_current_kprobe(struct kprobe *p,
390                         struct kprobe_ctlblk *kcb)
391 {
392         __get_cpu_var(current_kprobe) = p;
393 }
394
395 static void kretprobe_trampoline(void)
396 {
397 }
398
399 /*
400  * At this point the target function has been tricked into
401  * returning into our trampoline.  Lookup the associated instance
402  * and then:
403  *    - call the handler function
404  *    - cleanup by marking the instance as unused
405  *    - long jump back to the original return address
406  */
407 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
408 {
409         struct kretprobe_instance *ri = NULL;
410         struct hlist_head *head, empty_rp;
411         struct hlist_node *node, *tmp;
412         unsigned long flags, orig_ret_address = 0;
413         unsigned long trampoline_address =
414                 ((struct fnptr *)kretprobe_trampoline)->ip;
415
416         INIT_HLIST_HEAD(&empty_rp);
417         spin_lock_irqsave(&kretprobe_lock, flags);
418         head = kretprobe_inst_table_head(current);
419
420         /*
421          * It is possible to have multiple instances associated with a given
422          * task either because an multiple functions in the call path
423          * have a return probe installed on them, and/or more then one return
424          * return probe was registered for a target function.
425          *
426          * We can handle this because:
427          *     - instances are always inserted at the head of the list
428          *     - when multiple return probes are registered for the same
429          *       function, the first instance's ret_addr will point to the
430          *       real return address, and all the rest will point to
431          *       kretprobe_trampoline
432          */
433         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
434                 if (ri->task != current)
435                         /* another task is sharing our hash bucket */
436                         continue;
437
438                 if (ri->rp && ri->rp->handler)
439                         ri->rp->handler(ri, regs);
440
441                 orig_ret_address = (unsigned long)ri->ret_addr;
442                 recycle_rp_inst(ri, &empty_rp);
443
444                 if (orig_ret_address != trampoline_address)
445                         /*
446                          * This is the real return address. Any other
447                          * instances associated with this task are for
448                          * other calls deeper on the call stack
449                          */
450                         break;
451         }
452
453         kretprobe_assert(ri, orig_ret_address, trampoline_address);
454
455         regs->cr_iip = orig_ret_address;
456
457         reset_current_kprobe();
458         spin_unlock_irqrestore(&kretprobe_lock, flags);
459         preempt_enable_no_resched();
460
461         hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
462                 hlist_del(&ri->hlist);
463                 kfree(ri);
464         }
465         /*
466          * By returning a non-zero value, we are telling
467          * kprobe_handler() that we don't want the post_handler
468          * to run (and have re-enabled preemption)
469          */
470         return 1;
471 }
472
473 /* Called with kretprobe_lock held */
474 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
475                                       struct pt_regs *regs)
476 {
477         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
478
479         /* Replace the return addr with trampoline addr */
480         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
481 }
482
483 int __kprobes arch_prepare_kprobe(struct kprobe *p)
484 {
485         unsigned long addr = (unsigned long) p->addr;
486         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
487         unsigned long kprobe_inst=0;
488         unsigned int slot = addr & 0xf, template, major_opcode = 0;
489         bundle_t *bundle;
490         int qp;
491
492         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
493         template = bundle->quad0.template;
494
495         if(valid_kprobe_addr(template, slot, addr))
496                 return -EINVAL;
497
498         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
499         if (slot == 1 && bundle_encoding[template][1] == L)
500                 slot++;
501
502         /* Get kprobe_inst and major_opcode from the bundle */
503         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
504
505         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
506         if (qp < 0)
507                 return -EINVAL;
508
509         p->ainsn.insn = get_insn_slot();
510         if (!p->ainsn.insn)
511                 return -ENOMEM;
512         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
513         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
514
515         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
516
517         return 0;
518 }
519
520 void __kprobes arch_arm_kprobe(struct kprobe *p)
521 {
522         unsigned long arm_addr;
523         bundle_t *src, *dest;
524
525         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
526         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
527         src = &p->opcode.bundle;
528
529         flush_icache_range((unsigned long)p->ainsn.insn,
530                         (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
531         switch (p->ainsn.slot) {
532                 case 0:
533                         dest->quad0.slot0 = src->quad0.slot0;
534                         break;
535                 case 1:
536                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
537                         break;
538                 case 2:
539                         dest->quad1.slot2 = src->quad1.slot2;
540                         break;
541         }
542         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
543 }
544
545 void __kprobes arch_disarm_kprobe(struct kprobe *p)
546 {
547         unsigned long arm_addr;
548         bundle_t *src, *dest;
549
550         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
551         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
552         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
553         src = &p->ainsn.insn->bundle;
554         switch (p->ainsn.slot) {
555                 case 0:
556                         dest->quad0.slot0 = src->quad0.slot0;
557                         break;
558                 case 1:
559                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
560                         break;
561                 case 2:
562                         dest->quad1.slot2 = src->quad1.slot2;
563                         break;
564         }
565         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
566 }
567
568 void __kprobes arch_remove_kprobe(struct kprobe *p)
569 {
570         mutex_lock(&kprobe_mutex);
571         free_insn_slot(p->ainsn.insn, 0);
572         mutex_unlock(&kprobe_mutex);
573 }
574 /*
575  * We are resuming execution after a single step fault, so the pt_regs
576  * structure reflects the register state after we executed the instruction
577  * located in the kprobe (p->ainsn.insn.bundle).  We still need to adjust
578  * the ip to point back to the original stack address. To set the IP address
579  * to original stack address, handle the case where we need to fixup the
580  * relative IP address and/or fixup branch register.
581  */
582 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
583 {
584         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
585         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
586         unsigned long template;
587         int slot = ((unsigned long)p->addr & 0xf);
588
589         template = p->ainsn.insn->bundle.quad0.template;
590
591         if (slot == 1 && bundle_encoding[template][1] == L)
592                 slot = 2;
593
594         if (p->ainsn.inst_flag) {
595
596                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
597                         /* Fix relative IP address */
598                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
599                                         resume_addr;
600                 }
601
602                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
603                 /*
604                  * Fix target branch register, software convention is
605                  * to use either b0 or b6 or b7, so just checking
606                  * only those registers
607                  */
608                         switch (p->ainsn.target_br_reg) {
609                         case 0:
610                                 if ((regs->b0 == bundle_addr) ||
611                                         (regs->b0 == bundle_addr + 0x10)) {
612                                         regs->b0 = (regs->b0 - bundle_addr) +
613                                                 resume_addr;
614                                 }
615                                 break;
616                         case 6:
617                                 if ((regs->b6 == bundle_addr) ||
618                                         (regs->b6 == bundle_addr + 0x10)) {
619                                         regs->b6 = (regs->b6 - bundle_addr) +
620                                                 resume_addr;
621                                 }
622                                 break;
623                         case 7:
624                                 if ((regs->b7 == bundle_addr) ||
625                                         (regs->b7 == bundle_addr + 0x10)) {
626                                         regs->b7 = (regs->b7 - bundle_addr) +
627                                                 resume_addr;
628                                 }
629                                 break;
630                         } /* end switch */
631                 }
632                 goto turn_ss_off;
633         }
634
635         if (slot == 2) {
636                 if (regs->cr_iip == bundle_addr + 0x10) {
637                         regs->cr_iip = resume_addr + 0x10;
638                 }
639         } else {
640                 if (regs->cr_iip == bundle_addr) {
641                         regs->cr_iip = resume_addr;
642                 }
643         }
644
645 turn_ss_off:
646         /* Turn off Single Step bit */
647         ia64_psr(regs)->ss = 0;
648 }
649
650 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
651 {
652         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
653         unsigned long slot = (unsigned long)p->addr & 0xf;
654
655         /* single step inline if break instruction */
656         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
657                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
658         else
659                 regs->cr_iip = bundle_addr & ~0xFULL;
660
661         if (slot > 2)
662                 slot = 0;
663
664         ia64_psr(regs)->ri = slot;
665
666         /* turn on single stepping */
667         ia64_psr(regs)->ss = 1;
668 }
669
670 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
671 {
672         unsigned int slot = ia64_psr(regs)->ri;
673         unsigned int template, major_opcode;
674         unsigned long kprobe_inst;
675         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
676         bundle_t bundle;
677
678         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
679         template = bundle.quad0.template;
680
681         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
682         if (slot == 1 && bundle_encoding[template][1] == L)
683                 slot++;
684
685         /* Get Kprobe probe instruction at given slot*/
686         get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode);
687
688         /* For break instruction,
689          * Bits 37:40 Major opcode to be zero
690          * Bits 27:32 X6 to be zero
691          * Bits 32:35 X3 to be zero
692          */
693         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) {
694                 /* Not a break instruction */
695                 return 0;
696         }
697
698         /* Is a break instruction */
699         return 1;
700 }
701
702 static int __kprobes pre_kprobes_handler(struct die_args *args)
703 {
704         struct kprobe *p;
705         int ret = 0;
706         struct pt_regs *regs = args->regs;
707         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
708         struct kprobe_ctlblk *kcb;
709
710         /*
711          * We don't want to be preempted for the entire
712          * duration of kprobe processing
713          */
714         preempt_disable();
715         kcb = get_kprobe_ctlblk();
716
717         /* Handle recursion cases */
718         if (kprobe_running()) {
719                 p = get_kprobe(addr);
720                 if (p) {
721                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
722                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
723                                 ia64_psr(regs)->ss = 0;
724                                 goto no_kprobe;
725                         }
726                         /* We have reentered the pre_kprobe_handler(), since
727                          * another probe was hit while within the handler.
728                          * We here save the original kprobes variables and
729                          * just single step on the instruction of the new probe
730                          * without calling any user handlers.
731                          */
732                         save_previous_kprobe(kcb);
733                         set_current_kprobe(p, kcb);
734                         kprobes_inc_nmissed_count(p);
735                         prepare_ss(p, regs);
736                         kcb->kprobe_status = KPROBE_REENTER;
737                         return 1;
738                 } else if (args->err == __IA64_BREAK_JPROBE) {
739                         /*
740                          * jprobe instrumented function just completed
741                          */
742                         p = __get_cpu_var(current_kprobe);
743                         if (p->break_handler && p->break_handler(p, regs)) {
744                                 goto ss_probe;
745                         }
746                 } else if (!is_ia64_break_inst(regs)) {
747                         /* The breakpoint instruction was removed by
748                          * another cpu right after we hit, no further
749                          * handling of this interrupt is appropriate
750                          */
751                         ret = 1;
752                         goto no_kprobe;
753                 } else {
754                         /* Not our break */
755                         goto no_kprobe;
756                 }
757         }
758
759         p = get_kprobe(addr);
760         if (!p) {
761                 if (!is_ia64_break_inst(regs)) {
762                         /*
763                          * The breakpoint instruction was removed right
764                          * after we hit it.  Another cpu has removed
765                          * either a probepoint or a debugger breakpoint
766                          * at this address.  In either case, no further
767                          * handling of this interrupt is appropriate.
768                          */
769                         ret = 1;
770
771                 }
772
773                 /* Not one of our break, let kernel handle it */
774                 goto no_kprobe;
775         }
776
777         set_current_kprobe(p, kcb);
778         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
779
780         if (p->pre_handler && p->pre_handler(p, regs))
781                 /*
782                  * Our pre-handler is specifically requesting that we just
783                  * do a return.  This is used for both the jprobe pre-handler
784                  * and the kretprobe trampoline
785                  */
786                 return 1;
787
788 ss_probe:
789         prepare_ss(p, regs);
790         kcb->kprobe_status = KPROBE_HIT_SS;
791         return 1;
792
793 no_kprobe:
794         preempt_enable_no_resched();
795         return ret;
796 }
797
798 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
799 {
800         struct kprobe *cur = kprobe_running();
801         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
802
803         if (!cur)
804                 return 0;
805
806         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
807                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
808                 cur->post_handler(cur, regs, 0);
809         }
810
811         resume_execution(cur, regs);
812
813         /*Restore back the original saved kprobes variables and continue. */
814         if (kcb->kprobe_status == KPROBE_REENTER) {
815                 restore_previous_kprobe(kcb);
816                 goto out;
817         }
818         reset_current_kprobe();
819
820 out:
821         preempt_enable_no_resched();
822         return 1;
823 }
824
825 int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
826 {
827         struct kprobe *cur = kprobe_running();
828         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
829
830
831         switch(kcb->kprobe_status) {
832         case KPROBE_HIT_SS:
833         case KPROBE_REENTER:
834                 /*
835                  * We are here because the instruction being single
836                  * stepped caused a page fault. We reset the current
837                  * kprobe and the instruction pointer points back to
838                  * the probe address and allow the page fault handler
839                  * to continue as a normal page fault.
840                  */
841                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
842                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
843                 if (kcb->kprobe_status == KPROBE_REENTER)
844                         restore_previous_kprobe(kcb);
845                 else
846                         reset_current_kprobe();
847                 preempt_enable_no_resched();
848                 break;
849         case KPROBE_HIT_ACTIVE:
850         case KPROBE_HIT_SSDONE:
851                 /*
852                  * We increment the nmissed count for accounting,
853                  * we can also use npre/npostfault count for accouting
854                  * these specific fault cases.
855                  */
856                 kprobes_inc_nmissed_count(cur);
857
858                 /*
859                  * We come here because instructions in the pre/post
860                  * handler caused the page_fault, this could happen
861                  * if handler tries to access user space by
862                  * copy_from_user(), get_user() etc. Let the
863                  * user-specified handler try to fix it first.
864                  */
865                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
866                         return 1;
867                 /*
868                  * In case the user-specified fault handler returned
869                  * zero, try to fix up.
870                  */
871                 if (ia64_done_with_exception(regs))
872                         return 1;
873
874                 /*
875                  * Let ia64_do_page_fault() fix it.
876                  */
877                 break;
878         default:
879                 break;
880         }
881
882         return 0;
883 }
884
885 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
886                                        unsigned long val, void *data)
887 {
888         struct die_args *args = (struct die_args *)data;
889         int ret = NOTIFY_DONE;
890
891         if (args->regs && user_mode(args->regs))
892                 return ret;
893
894         switch(val) {
895         case DIE_BREAK:
896                 /* err is break number from ia64_bad_break() */
897                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
898                         || args->err == __IA64_BREAK_JPROBE
899                         || args->err == 0)
900                         if (pre_kprobes_handler(args))
901                                 ret = NOTIFY_STOP;
902                 break;
903         case DIE_FAULT:
904                 /* err is vector number from ia64_fault() */
905                 if (args->err == 36)
906                         if (post_kprobes_handler(args->regs))
907                                 ret = NOTIFY_STOP;
908                 break;
909         default:
910                 break;
911         }
912         return ret;
913 }
914
915 struct param_bsp_cfm {
916         unsigned long ip;
917         unsigned long *bsp;
918         unsigned long cfm;
919 };
920
921 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
922 {
923         unsigned long ip;
924         struct param_bsp_cfm *lp = arg;
925
926         do {
927                 unw_get_ip(info, &ip);
928                 if (ip == 0)
929                         break;
930                 if (ip == lp->ip) {
931                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
932                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
933                         return;
934                 }
935         } while (unw_unwind(info) >= 0);
936         lp->bsp = NULL;
937         lp->cfm = 0;
938         return;
939 }
940
941 unsigned long arch_deref_entry_point(void *entry)
942 {
943         return ((struct fnptr *)entry)->ip;
944 }
945
946 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
947 {
948         struct jprobe *jp = container_of(p, struct jprobe, kp);
949         unsigned long addr = arch_deref_entry_point(jp->entry);
950         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
951         struct param_bsp_cfm pa;
952         int bytes;
953
954         /*
955          * Callee owns the argument space and could overwrite it, eg
956          * tail call optimization. So to be absolutely safe
957          * we save the argument space before transferring the control
958          * to instrumented jprobe function which runs in
959          * the process context
960          */
961         pa.ip = regs->cr_iip;
962         unw_init_running(ia64_get_bsp_cfm, &pa);
963         bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
964                                 - (char *)pa.bsp;
965         memcpy( kcb->jprobes_saved_stacked_regs,
966                 pa.bsp,
967                 bytes );
968         kcb->bsp = pa.bsp;
969         kcb->cfm = pa.cfm;
970
971         /* save architectural state */
972         kcb->jprobe_saved_regs = *regs;
973
974         /* after rfi, execute the jprobe instrumented function */
975         regs->cr_iip = addr & ~0xFULL;
976         ia64_psr(regs)->ri = addr & 0xf;
977         regs->r1 = ((struct fnptr *)(jp->entry))->gp;
978
979         /*
980          * fix the return address to our jprobe_inst_return() function
981          * in the jprobes.S file
982          */
983         regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
984
985         return 1;
986 }
987
988 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
989 {
990         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
991         int bytes;
992
993         /* restoring architectural state */
994         *regs = kcb->jprobe_saved_regs;
995
996         /* restoring the original argument space */
997         flush_register_stack();
998         bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
999                                 - (char *)kcb->bsp;
1000         memcpy( kcb->bsp,
1001                 kcb->jprobes_saved_stacked_regs,
1002                 bytes );
1003         invalidate_stacked_regs();
1004
1005         preempt_enable_no_resched();
1006         return 1;
1007 }
1008
1009 static struct kprobe trampoline_p = {
1010         .pre_handler = trampoline_probe_handler
1011 };
1012
1013 int __init arch_init_kprobes(void)
1014 {
1015         trampoline_p.addr =
1016                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1017         return register_kprobe(&trampoline_p);
1018 }
1019
1020 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1021 {
1022         if (p->addr ==
1023                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1024                 return 1;
1025
1026         return 0;
1027 }