Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
[linux-2.6] / 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 /* Insert a long branch code */
82 static void __kprobes set_brl_inst(void *from, void *to)
83 {
84         s64 rel = ((s64) to - (s64) from) >> 4;
85         bundle_t *brl;
86         brl = (bundle_t *) ((u64) from & ~0xf);
87         brl->quad0.template = 0x05;     /* [MLX](stop) */
88         brl->quad0.slot0 = NOP_M_INST;  /* nop.m 0x0 */
89         brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
90         brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
91         /* brl.cond.sptk.many.clr rel<<4 (qp=0) */
92         brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
93 }
94
95 /*
96  * In this function we check to see if the instruction
97  * is IP relative instruction and update the kprobe
98  * inst flag accordingly
99  */
100 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
101                                               uint major_opcode,
102                                               unsigned long kprobe_inst,
103                                               struct kprobe *p)
104 {
105         p->ainsn.inst_flag = 0;
106         p->ainsn.target_br_reg = 0;
107         p->ainsn.slot = slot;
108
109         /* Check for Break instruction
110          * Bits 37:40 Major opcode to be zero
111          * Bits 27:32 X6 to be zero
112          * Bits 32:35 X3 to be zero
113          */
114         if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
115                 /* is a break instruction */
116                 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
117                 return;
118         }
119
120         if (bundle_encoding[template][slot] == B) {
121                 switch (major_opcode) {
122                   case INDIRECT_CALL_OPCODE:
123                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
124                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
125                         break;
126                   case IP_RELATIVE_PREDICT_OPCODE:
127                   case IP_RELATIVE_BRANCH_OPCODE:
128                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
129                         break;
130                   case IP_RELATIVE_CALL_OPCODE:
131                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
132                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
133                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
134                         break;
135                 }
136         } else if (bundle_encoding[template][slot] == X) {
137                 switch (major_opcode) {
138                   case LONG_CALL_OPCODE:
139                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
140                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
141                   break;
142                 }
143         }
144         return;
145 }
146
147 /*
148  * In this function we check to see if the instruction
149  * (qp) cmpx.crel.ctype p1,p2=r2,r3
150  * on which we are inserting kprobe is cmp instruction
151  * with ctype as unc.
152  */
153 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
154                                             uint major_opcode,
155                                             unsigned long kprobe_inst)
156 {
157         cmp_inst_t cmp_inst;
158         uint ctype_unc = 0;
159
160         if (!((bundle_encoding[template][slot] == I) ||
161                 (bundle_encoding[template][slot] == M)))
162                 goto out;
163
164         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
165                 (major_opcode == 0xE)))
166                 goto out;
167
168         cmp_inst.l = kprobe_inst;
169         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
170                 /* Integer compare - Register Register (A6 type)*/
171                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
172                                 &&(cmp_inst.f.c == 1))
173                         ctype_unc = 1;
174         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
175                 /* Integer compare - Immediate Register (A8 type)*/
176                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
177                         ctype_unc = 1;
178         }
179 out:
180         return ctype_unc;
181 }
182
183 /*
184  * In this function we check to see if the instruction
185  * on which we are inserting kprobe is supported.
186  * Returns qp value if supported
187  * Returns -EINVAL if unsupported
188  */
189 static int __kprobes unsupported_inst(uint template, uint  slot,
190                                       uint major_opcode,
191                                       unsigned long kprobe_inst,
192                                       unsigned long addr)
193 {
194         int qp;
195
196         qp = kprobe_inst & 0x3f;
197         if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
198                 if (slot == 1 && qp)  {
199                         printk(KERN_WARNING "Kprobes on cmp unc "
200                                         "instruction on slot 1 at <0x%lx> "
201                                         "is not supported\n", addr);
202                         return -EINVAL;
203
204                 }
205                 qp = 0;
206         }
207         else if (bundle_encoding[template][slot] == I) {
208                 if (major_opcode == 0) {
209                         /*
210                          * Check for Integer speculation instruction
211                          * - Bit 33-35 to be equal to 0x1
212                          */
213                         if (((kprobe_inst >> 33) & 0x7) == 1) {
214                                 printk(KERN_WARNING
215                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
216                                                 addr);
217                                 return -EINVAL;
218                         }
219                         /*
220                          * IP relative mov instruction
221                          *  - Bit 27-35 to be equal to 0x30
222                          */
223                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
224                                 printk(KERN_WARNING
225                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
226                                                 addr);
227                                 return -EINVAL;
228
229                         }
230                 }
231                 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
232                                 (kprobe_inst & (0x1UL << 12))) {
233                         /* test bit instructions, tbit,tnat,tf
234                          * bit 33-36 to be equal to 0
235                          * bit 12 to be equal to 1
236                          */
237                         if (slot == 1 && qp) {
238                                 printk(KERN_WARNING "Kprobes on test bit "
239                                                 "instruction on slot at <0x%lx> "
240                                                 "is not supported\n", addr);
241                                 return -EINVAL;
242                         }
243                         qp = 0;
244                 }
245         }
246         else if (bundle_encoding[template][slot] == B) {
247                 if (major_opcode == 7) {
248                         /* IP-Relative Predict major code is 7 */
249                         printk(KERN_WARNING "Kprobes on IP-Relative"
250                                         "Predict is not supported\n");
251                         return -EINVAL;
252                 }
253                 else if (major_opcode == 2) {
254                         /* Indirect Predict, major code is 2
255                          * bit 27-32 to be equal to 10 or 11
256                          */
257                         int x6=(kprobe_inst >> 27) & 0x3F;
258                         if ((x6 == 0x10) || (x6 == 0x11)) {
259                                 printk(KERN_WARNING "Kprobes on "
260                                         "Indirect Predict is not supported\n");
261                                 return -EINVAL;
262                         }
263                 }
264         }
265         /* kernel does not use float instruction, here for safety kprobe
266          * will judge whether it is fcmp/flass/float approximation instruction
267          */
268         else if (unlikely(bundle_encoding[template][slot] == F)) {
269                 if ((major_opcode == 4 || major_opcode == 5) &&
270                                 (kprobe_inst  & (0x1 << 12))) {
271                         /* fcmp/fclass unc instruction */
272                         if (slot == 1 && qp) {
273                                 printk(KERN_WARNING "Kprobes on fcmp/fclass "
274                                         "instruction on slot at <0x%lx> "
275                                         "is not supported\n", addr);
276                                 return -EINVAL;
277
278                         }
279                         qp = 0;
280                 }
281                 if ((major_opcode == 0 || major_opcode == 1) &&
282                         (kprobe_inst & (0x1UL << 33))) {
283                         /* float Approximation instruction */
284                         if (slot == 1 && qp) {
285                                 printk(KERN_WARNING "Kprobes on float Approx "
286                                         "instr at <0x%lx> is not supported\n",
287                                                 addr);
288                                 return -EINVAL;
289                         }
290                         qp = 0;
291                 }
292         }
293         return qp;
294 }
295
296 /*
297  * In this function we override the bundle with
298  * the break instruction at the given slot.
299  */
300 static void __kprobes prepare_break_inst(uint template, uint  slot,
301                                          uint major_opcode,
302                                          unsigned long kprobe_inst,
303                                          struct kprobe *p,
304                                          int qp)
305 {
306         unsigned long break_inst = BREAK_INST;
307         bundle_t *bundle = &p->opcode.bundle;
308
309         /*
310          * Copy the original kprobe_inst qualifying predicate(qp)
311          * to the break instruction
312          */
313         break_inst |= qp;
314
315         switch (slot) {
316           case 0:
317                 bundle->quad0.slot0 = break_inst;
318                 break;
319           case 1:
320                 bundle->quad0.slot1_p0 = break_inst;
321                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
322                 break;
323           case 2:
324                 bundle->quad1.slot2 = break_inst;
325                 break;
326         }
327
328         /*
329          * Update the instruction flag, so that we can
330          * emulate the instruction properly after we
331          * single step on original instruction
332          */
333         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
334 }
335
336 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
337                 unsigned long *kprobe_inst, uint *major_opcode)
338 {
339         unsigned long kprobe_inst_p0, kprobe_inst_p1;
340         unsigned int template;
341
342         template = bundle->quad0.template;
343
344         switch (slot) {
345           case 0:
346                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
347                 *kprobe_inst = bundle->quad0.slot0;
348                   break;
349           case 1:
350                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
351                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
352                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
353                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
354                 break;
355           case 2:
356                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
357                 *kprobe_inst = bundle->quad1.slot2;
358                 break;
359         }
360 }
361
362 /* Returns non-zero if the addr is in the Interrupt Vector Table */
363 static int __kprobes in_ivt_functions(unsigned long addr)
364 {
365         return (addr >= (unsigned long)__start_ivt_text
366                 && addr < (unsigned long)__end_ivt_text);
367 }
368
369 static int __kprobes valid_kprobe_addr(int template, int slot,
370                                        unsigned long addr)
371 {
372         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
373                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
374                                 "at 0x%lx\n", addr);
375                 return -EINVAL;
376         }
377
378         if (in_ivt_functions(addr)) {
379                 printk(KERN_WARNING "Kprobes can't be inserted inside "
380                                 "IVT functions at 0x%lx\n", addr);
381                 return -EINVAL;
382         }
383
384         return 0;
385 }
386
387 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
388 {
389         unsigned int i;
390         i = atomic_add_return(1, &kcb->prev_kprobe_index);
391         kcb->prev_kprobe[i-1].kp = kprobe_running();
392         kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
393 }
394
395 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
396 {
397         unsigned int i;
398         i = atomic_read(&kcb->prev_kprobe_index);
399         __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i-1].kp;
400         kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
401         atomic_sub(1, &kcb->prev_kprobe_index);
402 }
403
404 static void __kprobes set_current_kprobe(struct kprobe *p,
405                         struct kprobe_ctlblk *kcb)
406 {
407         __get_cpu_var(current_kprobe) = p;
408 }
409
410 static void kretprobe_trampoline(void)
411 {
412 }
413
414 /*
415  * At this point the target function has been tricked into
416  * returning into our trampoline.  Lookup the associated instance
417  * and then:
418  *    - call the handler function
419  *    - cleanup by marking the instance as unused
420  *    - long jump back to the original return address
421  */
422 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
423 {
424         struct kretprobe_instance *ri = NULL;
425         struct hlist_head *head, empty_rp;
426         struct hlist_node *node, *tmp;
427         unsigned long flags, orig_ret_address = 0;
428         unsigned long trampoline_address =
429                 ((struct fnptr *)kretprobe_trampoline)->ip;
430
431         INIT_HLIST_HEAD(&empty_rp);
432         kretprobe_hash_lock(current, &head, &flags);
433
434         /*
435          * It is possible to have multiple instances associated with a given
436          * task either because an multiple functions in the call path
437          * have a return probe installed on them, and/or more then one return
438          * return probe was registered for a target function.
439          *
440          * We can handle this because:
441          *     - instances are always inserted at the head of the list
442          *     - when multiple return probes are registered for the same
443          *       function, the first instance's ret_addr will point to the
444          *       real return address, and all the rest will point to
445          *       kretprobe_trampoline
446          */
447         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
448                 if (ri->task != current)
449                         /* another task is sharing our hash bucket */
450                         continue;
451
452                 orig_ret_address = (unsigned long)ri->ret_addr;
453                 if (orig_ret_address != trampoline_address)
454                         /*
455                          * This is the real return address. Any other
456                          * instances associated with this task are for
457                          * other calls deeper on the call stack
458                          */
459                         break;
460         }
461
462         regs->cr_iip = orig_ret_address;
463
464         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
465                 if (ri->task != current)
466                         /* another task is sharing our hash bucket */
467                         continue;
468
469                 if (ri->rp && ri->rp->handler)
470                         ri->rp->handler(ri, regs);
471
472                 orig_ret_address = (unsigned long)ri->ret_addr;
473                 recycle_rp_inst(ri, &empty_rp);
474
475                 if (orig_ret_address != trampoline_address)
476                         /*
477                          * This is the real return address. Any other
478                          * instances associated with this task are for
479                          * other calls deeper on the call stack
480                          */
481                         break;
482         }
483
484         kretprobe_assert(ri, orig_ret_address, trampoline_address);
485
486         reset_current_kprobe();
487         kretprobe_hash_unlock(current, &flags);
488         preempt_enable_no_resched();
489
490         hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
491                 hlist_del(&ri->hlist);
492                 kfree(ri);
493         }
494         /*
495          * By returning a non-zero value, we are telling
496          * kprobe_handler() that we don't want the post_handler
497          * to run (and have re-enabled preemption)
498          */
499         return 1;
500 }
501
502 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
503                                       struct pt_regs *regs)
504 {
505         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
506
507         /* Replace the return addr with trampoline addr */
508         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
509 }
510
511 /* Check the instruction in the slot is break */
512 static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
513 {
514         unsigned int major_opcode;
515         unsigned int template = bundle->quad0.template;
516         unsigned long kprobe_inst;
517
518         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
519         if (slot == 1 && bundle_encoding[template][1] == L)
520                 slot++;
521
522         /* Get Kprobe probe instruction at given slot*/
523         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
524
525         /* For break instruction,
526          * Bits 37:40 Major opcode to be zero
527          * Bits 27:32 X6 to be zero
528          * Bits 32:35 X3 to be zero
529          */
530         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
531                 /* Not a break instruction */
532                 return 0;
533         }
534
535         /* Is a break instruction */
536         return 1;
537 }
538
539 /*
540  * In this function, we check whether the target bundle modifies IP or
541  * it triggers an exception. If so, it cannot be boostable.
542  */
543 static int __kprobes can_boost(bundle_t *bundle, uint slot,
544                                unsigned long bundle_addr)
545 {
546         unsigned int template = bundle->quad0.template;
547
548         do {
549                 if (search_exception_tables(bundle_addr + slot) ||
550                     __is_ia64_break_inst(bundle, slot))
551                         return 0;       /* exception may occur in this bundle*/
552         } while ((++slot) < 3);
553         template &= 0x1e;
554         if (template >= 0x10 /* including B unit */ ||
555             template == 0x04 /* including X unit */ ||
556             template == 0x06) /* undefined */
557                 return 0;
558
559         return 1;
560 }
561
562 /* Prepare long jump bundle and disables other boosters if need */
563 static void __kprobes prepare_booster(struct kprobe *p)
564 {
565         unsigned long addr = (unsigned long)p->addr & ~0xFULL;
566         unsigned int slot = (unsigned long)p->addr & 0xf;
567         struct kprobe *other_kp;
568
569         if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
570                 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
571                 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
572         }
573
574         /* disables boosters in previous slots */
575         for (; addr < (unsigned long)p->addr; addr++) {
576                 other_kp = get_kprobe((void *)addr);
577                 if (other_kp)
578                         other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
579         }
580 }
581
582 int __kprobes arch_prepare_kprobe(struct kprobe *p)
583 {
584         unsigned long addr = (unsigned long) p->addr;
585         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
586         unsigned long kprobe_inst=0;
587         unsigned int slot = addr & 0xf, template, major_opcode = 0;
588         bundle_t *bundle;
589         int qp;
590
591         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
592         template = bundle->quad0.template;
593
594         if(valid_kprobe_addr(template, slot, addr))
595                 return -EINVAL;
596
597         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
598         if (slot == 1 && bundle_encoding[template][1] == L)
599                 slot++;
600
601         /* Get kprobe_inst and major_opcode from the bundle */
602         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
603
604         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
605         if (qp < 0)
606                 return -EINVAL;
607
608         p->ainsn.insn = get_insn_slot();
609         if (!p->ainsn.insn)
610                 return -ENOMEM;
611         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
612         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
613
614         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
615
616         prepare_booster(p);
617
618         return 0;
619 }
620
621 void __kprobes arch_arm_kprobe(struct kprobe *p)
622 {
623         unsigned long arm_addr;
624         bundle_t *src, *dest;
625
626         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
627         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
628         src = &p->opcode.bundle;
629
630         flush_icache_range((unsigned long)p->ainsn.insn,
631                            (unsigned long)p->ainsn.insn +
632                            sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
633
634         switch (p->ainsn.slot) {
635                 case 0:
636                         dest->quad0.slot0 = src->quad0.slot0;
637                         break;
638                 case 1:
639                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
640                         break;
641                 case 2:
642                         dest->quad1.slot2 = src->quad1.slot2;
643                         break;
644         }
645         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
646 }
647
648 void __kprobes arch_disarm_kprobe(struct kprobe *p)
649 {
650         unsigned long arm_addr;
651         bundle_t *src, *dest;
652
653         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
654         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
655         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
656         src = &p->ainsn.insn->bundle;
657         switch (p->ainsn.slot) {
658                 case 0:
659                         dest->quad0.slot0 = src->quad0.slot0;
660                         break;
661                 case 1:
662                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
663                         break;
664                 case 2:
665                         dest->quad1.slot2 = src->quad1.slot2;
666                         break;
667         }
668         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
669 }
670
671 void __kprobes arch_remove_kprobe(struct kprobe *p)
672 {
673         mutex_lock(&kprobe_mutex);
674         free_insn_slot(p->ainsn.insn, p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
675         mutex_unlock(&kprobe_mutex);
676 }
677 /*
678  * We are resuming execution after a single step fault, so the pt_regs
679  * structure reflects the register state after we executed the instruction
680  * located in the kprobe (p->ainsn.insn->bundle).  We still need to adjust
681  * the ip to point back to the original stack address. To set the IP address
682  * to original stack address, handle the case where we need to fixup the
683  * relative IP address and/or fixup branch register.
684  */
685 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
686 {
687         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
688         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
689         unsigned long template;
690         int slot = ((unsigned long)p->addr & 0xf);
691
692         template = p->ainsn.insn->bundle.quad0.template;
693
694         if (slot == 1 && bundle_encoding[template][1] == L)
695                 slot = 2;
696
697         if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
698
699                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
700                         /* Fix relative IP address */
701                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
702                                         resume_addr;
703                 }
704
705                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
706                 /*
707                  * Fix target branch register, software convention is
708                  * to use either b0 or b6 or b7, so just checking
709                  * only those registers
710                  */
711                         switch (p->ainsn.target_br_reg) {
712                         case 0:
713                                 if ((regs->b0 == bundle_addr) ||
714                                         (regs->b0 == bundle_addr + 0x10)) {
715                                         regs->b0 = (regs->b0 - bundle_addr) +
716                                                 resume_addr;
717                                 }
718                                 break;
719                         case 6:
720                                 if ((regs->b6 == bundle_addr) ||
721                                         (regs->b6 == bundle_addr + 0x10)) {
722                                         regs->b6 = (regs->b6 - bundle_addr) +
723                                                 resume_addr;
724                                 }
725                                 break;
726                         case 7:
727                                 if ((regs->b7 == bundle_addr) ||
728                                         (regs->b7 == bundle_addr + 0x10)) {
729                                         regs->b7 = (regs->b7 - bundle_addr) +
730                                                 resume_addr;
731                                 }
732                                 break;
733                         } /* end switch */
734                 }
735                 goto turn_ss_off;
736         }
737
738         if (slot == 2) {
739                 if (regs->cr_iip == bundle_addr + 0x10) {
740                         regs->cr_iip = resume_addr + 0x10;
741                 }
742         } else {
743                 if (regs->cr_iip == bundle_addr) {
744                         regs->cr_iip = resume_addr;
745                 }
746         }
747
748 turn_ss_off:
749         /* Turn off Single Step bit */
750         ia64_psr(regs)->ss = 0;
751 }
752
753 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
754 {
755         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
756         unsigned long slot = (unsigned long)p->addr & 0xf;
757
758         /* single step inline if break instruction */
759         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
760                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
761         else
762                 regs->cr_iip = bundle_addr & ~0xFULL;
763
764         if (slot > 2)
765                 slot = 0;
766
767         ia64_psr(regs)->ri = slot;
768
769         /* turn on single stepping */
770         ia64_psr(regs)->ss = 1;
771 }
772
773 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
774 {
775         unsigned int slot = ia64_psr(regs)->ri;
776         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
777         bundle_t bundle;
778
779         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
780
781         return __is_ia64_break_inst(&bundle, slot);
782 }
783
784 static int __kprobes pre_kprobes_handler(struct die_args *args)
785 {
786         struct kprobe *p;
787         int ret = 0;
788         struct pt_regs *regs = args->regs;
789         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
790         struct kprobe_ctlblk *kcb;
791
792         /*
793          * We don't want to be preempted for the entire
794          * duration of kprobe processing
795          */
796         preempt_disable();
797         kcb = get_kprobe_ctlblk();
798
799         /* Handle recursion cases */
800         if (kprobe_running()) {
801                 p = get_kprobe(addr);
802                 if (p) {
803                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
804                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
805                                 ia64_psr(regs)->ss = 0;
806                                 goto no_kprobe;
807                         }
808                         /* We have reentered the pre_kprobe_handler(), since
809                          * another probe was hit while within the handler.
810                          * We here save the original kprobes variables and
811                          * just single step on the instruction of the new probe
812                          * without calling any user handlers.
813                          */
814                         save_previous_kprobe(kcb);
815                         set_current_kprobe(p, kcb);
816                         kprobes_inc_nmissed_count(p);
817                         prepare_ss(p, regs);
818                         kcb->kprobe_status = KPROBE_REENTER;
819                         return 1;
820                 } else if (args->err == __IA64_BREAK_JPROBE) {
821                         /*
822                          * jprobe instrumented function just completed
823                          */
824                         p = __get_cpu_var(current_kprobe);
825                         if (p->break_handler && p->break_handler(p, regs)) {
826                                 goto ss_probe;
827                         }
828                 } else if (!is_ia64_break_inst(regs)) {
829                         /* The breakpoint instruction was removed by
830                          * another cpu right after we hit, no further
831                          * handling of this interrupt is appropriate
832                          */
833                         ret = 1;
834                         goto no_kprobe;
835                 } else {
836                         /* Not our break */
837                         goto no_kprobe;
838                 }
839         }
840
841         p = get_kprobe(addr);
842         if (!p) {
843                 if (!is_ia64_break_inst(regs)) {
844                         /*
845                          * The breakpoint instruction was removed right
846                          * after we hit it.  Another cpu has removed
847                          * either a probepoint or a debugger breakpoint
848                          * at this address.  In either case, no further
849                          * handling of this interrupt is appropriate.
850                          */
851                         ret = 1;
852
853                 }
854
855                 /* Not one of our break, let kernel handle it */
856                 goto no_kprobe;
857         }
858
859         set_current_kprobe(p, kcb);
860         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
861
862         if (p->pre_handler && p->pre_handler(p, regs))
863                 /*
864                  * Our pre-handler is specifically requesting that we just
865                  * do a return.  This is used for both the jprobe pre-handler
866                  * and the kretprobe trampoline
867                  */
868                 return 1;
869
870 ss_probe:
871 #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
872         if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
873                 /* Boost up -- we can execute copied instructions directly */
874                 ia64_psr(regs)->ri = p->ainsn.slot;
875                 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
876                 /* turn single stepping off */
877                 ia64_psr(regs)->ss = 0;
878
879                 reset_current_kprobe();
880                 preempt_enable_no_resched();
881                 return 1;
882         }
883 #endif
884         prepare_ss(p, regs);
885         kcb->kprobe_status = KPROBE_HIT_SS;
886         return 1;
887
888 no_kprobe:
889         preempt_enable_no_resched();
890         return ret;
891 }
892
893 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
894 {
895         struct kprobe *cur = kprobe_running();
896         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
897
898         if (!cur)
899                 return 0;
900
901         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
902                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
903                 cur->post_handler(cur, regs, 0);
904         }
905
906         resume_execution(cur, regs);
907
908         /*Restore back the original saved kprobes variables and continue. */
909         if (kcb->kprobe_status == KPROBE_REENTER) {
910                 restore_previous_kprobe(kcb);
911                 goto out;
912         }
913         reset_current_kprobe();
914
915 out:
916         preempt_enable_no_resched();
917         return 1;
918 }
919
920 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
921 {
922         struct kprobe *cur = kprobe_running();
923         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
924
925
926         switch(kcb->kprobe_status) {
927         case KPROBE_HIT_SS:
928         case KPROBE_REENTER:
929                 /*
930                  * We are here because the instruction being single
931                  * stepped caused a page fault. We reset the current
932                  * kprobe and the instruction pointer points back to
933                  * the probe address and allow the page fault handler
934                  * to continue as a normal page fault.
935                  */
936                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
937                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
938                 if (kcb->kprobe_status == KPROBE_REENTER)
939                         restore_previous_kprobe(kcb);
940                 else
941                         reset_current_kprobe();
942                 preempt_enable_no_resched();
943                 break;
944         case KPROBE_HIT_ACTIVE:
945         case KPROBE_HIT_SSDONE:
946                 /*
947                  * We increment the nmissed count for accounting,
948                  * we can also use npre/npostfault count for accouting
949                  * these specific fault cases.
950                  */
951                 kprobes_inc_nmissed_count(cur);
952
953                 /*
954                  * We come here because instructions in the pre/post
955                  * handler caused the page_fault, this could happen
956                  * if handler tries to access user space by
957                  * copy_from_user(), get_user() etc. Let the
958                  * user-specified handler try to fix it first.
959                  */
960                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
961                         return 1;
962                 /*
963                  * In case the user-specified fault handler returned
964                  * zero, try to fix up.
965                  */
966                 if (ia64_done_with_exception(regs))
967                         return 1;
968
969                 /*
970                  * Let ia64_do_page_fault() fix it.
971                  */
972                 break;
973         default:
974                 break;
975         }
976
977         return 0;
978 }
979
980 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
981                                        unsigned long val, void *data)
982 {
983         struct die_args *args = (struct die_args *)data;
984         int ret = NOTIFY_DONE;
985
986         if (args->regs && user_mode(args->regs))
987                 return ret;
988
989         switch(val) {
990         case DIE_BREAK:
991                 /* err is break number from ia64_bad_break() */
992                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
993                         || args->err == __IA64_BREAK_JPROBE
994                         || args->err == 0)
995                         if (pre_kprobes_handler(args))
996                                 ret = NOTIFY_STOP;
997                 break;
998         case DIE_FAULT:
999                 /* err is vector number from ia64_fault() */
1000                 if (args->err == 36)
1001                         if (post_kprobes_handler(args->regs))
1002                                 ret = NOTIFY_STOP;
1003                 break;
1004         default:
1005                 break;
1006         }
1007         return ret;
1008 }
1009
1010 struct param_bsp_cfm {
1011         unsigned long ip;
1012         unsigned long *bsp;
1013         unsigned long cfm;
1014 };
1015
1016 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
1017 {
1018         unsigned long ip;
1019         struct param_bsp_cfm *lp = arg;
1020
1021         do {
1022                 unw_get_ip(info, &ip);
1023                 if (ip == 0)
1024                         break;
1025                 if (ip == lp->ip) {
1026                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
1027                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
1028                         return;
1029                 }
1030         } while (unw_unwind(info) >= 0);
1031         lp->bsp = NULL;
1032         lp->cfm = 0;
1033         return;
1034 }
1035
1036 unsigned long arch_deref_entry_point(void *entry)
1037 {
1038         return ((struct fnptr *)entry)->ip;
1039 }
1040
1041 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
1042 {
1043         struct jprobe *jp = container_of(p, struct jprobe, kp);
1044         unsigned long addr = arch_deref_entry_point(jp->entry);
1045         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1046         struct param_bsp_cfm pa;
1047         int bytes;
1048
1049         /*
1050          * Callee owns the argument space and could overwrite it, eg
1051          * tail call optimization. So to be absolutely safe
1052          * we save the argument space before transferring the control
1053          * to instrumented jprobe function which runs in
1054          * the process context
1055          */
1056         pa.ip = regs->cr_iip;
1057         unw_init_running(ia64_get_bsp_cfm, &pa);
1058         bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
1059                                 - (char *)pa.bsp;
1060         memcpy( kcb->jprobes_saved_stacked_regs,
1061                 pa.bsp,
1062                 bytes );
1063         kcb->bsp = pa.bsp;
1064         kcb->cfm = pa.cfm;
1065
1066         /* save architectural state */
1067         kcb->jprobe_saved_regs = *regs;
1068
1069         /* after rfi, execute the jprobe instrumented function */
1070         regs->cr_iip = addr & ~0xFULL;
1071         ia64_psr(regs)->ri = addr & 0xf;
1072         regs->r1 = ((struct fnptr *)(jp->entry))->gp;
1073
1074         /*
1075          * fix the return address to our jprobe_inst_return() function
1076          * in the jprobes.S file
1077          */
1078         regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
1079
1080         return 1;
1081 }
1082
1083 /* ia64 does not need this */
1084 void __kprobes jprobe_return(void)
1085 {
1086 }
1087
1088 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
1089 {
1090         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1091         int bytes;
1092
1093         /* restoring architectural state */
1094         *regs = kcb->jprobe_saved_regs;
1095
1096         /* restoring the original argument space */
1097         flush_register_stack();
1098         bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
1099                                 - (char *)kcb->bsp;
1100         memcpy( kcb->bsp,
1101                 kcb->jprobes_saved_stacked_regs,
1102                 bytes );
1103         invalidate_stacked_regs();
1104
1105         preempt_enable_no_resched();
1106         return 1;
1107 }
1108
1109 static struct kprobe trampoline_p = {
1110         .pre_handler = trampoline_probe_handler
1111 };
1112
1113 int __init arch_init_kprobes(void)
1114 {
1115         trampoline_p.addr =
1116                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1117         return register_kprobe(&trampoline_p);
1118 }
1119
1120 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1121 {
1122         if (p->addr ==
1123                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1124                 return 1;
1125
1126         return 0;
1127 }