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TOMOYO Linux Cross Reference
Linux/arch/ia64/kernel/kprobes.c

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  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         __this_cpu_write(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         __this_cpu_write(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 *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 than 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, 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, 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, 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         if (p->ainsn.insn) {
674                 free_insn_slot(p->ainsn.insn,
675                                p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
676                 p->ainsn.insn = NULL;
677         }
678 }
679 /*
680  * We are resuming execution after a single step fault, so the pt_regs
681  * structure reflects the register state after we executed the instruction
682  * located in the kprobe (p->ainsn.insn->bundle).  We still need to adjust
683  * the ip to point back to the original stack address. To set the IP address
684  * to original stack address, handle the case where we need to fixup the
685  * relative IP address and/or fixup branch register.
686  */
687 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
688 {
689         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
690         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
691         unsigned long template;
692         int slot = ((unsigned long)p->addr & 0xf);
693 
694         template = p->ainsn.insn->bundle.quad0.template;
695 
696         if (slot == 1 && bundle_encoding[template][1] == L)
697                 slot = 2;
698 
699         if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
700 
701                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
702                         /* Fix relative IP address */
703                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
704                                         resume_addr;
705                 }
706 
707                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
708                 /*
709                  * Fix target branch register, software convention is
710                  * to use either b0 or b6 or b7, so just checking
711                  * only those registers
712                  */
713                         switch (p->ainsn.target_br_reg) {
714                         case 0:
715                                 if ((regs->b0 == bundle_addr) ||
716                                         (regs->b0 == bundle_addr + 0x10)) {
717                                         regs->b0 = (regs->b0 - bundle_addr) +
718                                                 resume_addr;
719                                 }
720                                 break;
721                         case 6:
722                                 if ((regs->b6 == bundle_addr) ||
723                                         (regs->b6 == bundle_addr + 0x10)) {
724                                         regs->b6 = (regs->b6 - bundle_addr) +
725                                                 resume_addr;
726                                 }
727                                 break;
728                         case 7:
729                                 if ((regs->b7 == bundle_addr) ||
730                                         (regs->b7 == bundle_addr + 0x10)) {
731                                         regs->b7 = (regs->b7 - bundle_addr) +
732                                                 resume_addr;
733                                 }
734                                 break;
735                         } /* end switch */
736                 }
737                 goto turn_ss_off;
738         }
739 
740         if (slot == 2) {
741                 if (regs->cr_iip == bundle_addr + 0x10) {
742                         regs->cr_iip = resume_addr + 0x10;
743                 }
744         } else {
745                 if (regs->cr_iip == bundle_addr) {
746                         regs->cr_iip = resume_addr;
747                 }
748         }
749 
750 turn_ss_off:
751         /* Turn off Single Step bit */
752         ia64_psr(regs)->ss = 0;
753 }
754 
755 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
756 {
757         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
758         unsigned long slot = (unsigned long)p->addr & 0xf;
759 
760         /* single step inline if break instruction */
761         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
762                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
763         else
764                 regs->cr_iip = bundle_addr & ~0xFULL;
765 
766         if (slot > 2)
767                 slot = 0;
768 
769         ia64_psr(regs)->ri = slot;
770 
771         /* turn on single stepping */
772         ia64_psr(regs)->ss = 1;
773 }
774 
775 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
776 {
777         unsigned int slot = ia64_psr(regs)->ri;
778         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
779         bundle_t bundle;
780 
781         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
782 
783         return __is_ia64_break_inst(&bundle, slot);
784 }
785 
786 static int __kprobes pre_kprobes_handler(struct die_args *args)
787 {
788         struct kprobe *p;
789         int ret = 0;
790         struct pt_regs *regs = args->regs;
791         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
792         struct kprobe_ctlblk *kcb;
793 
794         /*
795          * We don't want to be preempted for the entire
796          * duration of kprobe processing
797          */
798         preempt_disable();
799         kcb = get_kprobe_ctlblk();
800 
801         /* Handle recursion cases */
802         if (kprobe_running()) {
803                 p = get_kprobe(addr);
804                 if (p) {
805                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
806                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
807                                 ia64_psr(regs)->ss = 0;
808                                 goto no_kprobe;
809                         }
810                         /* We have reentered the pre_kprobe_handler(), since
811                          * another probe was hit while within the handler.
812                          * We here save the original kprobes variables and
813                          * just single step on the instruction of the new probe
814                          * without calling any user handlers.
815                          */
816                         save_previous_kprobe(kcb);
817                         set_current_kprobe(p, kcb);
818                         kprobes_inc_nmissed_count(p);
819                         prepare_ss(p, regs);
820                         kcb->kprobe_status = KPROBE_REENTER;
821                         return 1;
822                 } else if (args->err == __IA64_BREAK_JPROBE) {
823                         /*
824                          * jprobe instrumented function just completed
825                          */
826                         p = __this_cpu_read(current_kprobe);
827                         if (p->break_handler && p->break_handler(p, regs)) {
828                                 goto ss_probe;
829                         }
830                 } else if (!is_ia64_break_inst(regs)) {
831                         /* The breakpoint instruction was removed by
832                          * another cpu right after we hit, no further
833                          * handling of this interrupt is appropriate
834                          */
835                         ret = 1;
836                         goto no_kprobe;
837                 } else {
838                         /* Not our break */
839                         goto no_kprobe;
840                 }
841         }
842 
843         p = get_kprobe(addr);
844         if (!p) {
845                 if (!is_ia64_break_inst(regs)) {
846                         /*
847                          * The breakpoint instruction was removed right
848                          * after we hit it.  Another cpu has removed
849                          * either a probepoint or a debugger breakpoint
850                          * at this address.  In either case, no further
851                          * handling of this interrupt is appropriate.
852                          */
853                         ret = 1;
854 
855                 }
856 
857                 /* Not one of our break, let kernel handle it */
858                 goto no_kprobe;
859         }
860 
861         set_current_kprobe(p, kcb);
862         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
863 
864         if (p->pre_handler && p->pre_handler(p, regs))
865                 /*
866                  * Our pre-handler is specifically requesting that we just
867                  * do a return.  This is used for both the jprobe pre-handler
868                  * and the kretprobe trampoline
869                  */
870                 return 1;
871 
872 ss_probe:
873 #if !defined(CONFIG_PREEMPT)
874         if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
875                 /* Boost up -- we can execute copied instructions directly */
876                 ia64_psr(regs)->ri = p->ainsn.slot;
877                 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
878                 /* turn single stepping off */
879                 ia64_psr(regs)->ss = 0;
880 
881                 reset_current_kprobe();
882                 preempt_enable_no_resched();
883                 return 1;
884         }
885 #endif
886         prepare_ss(p, regs);
887         kcb->kprobe_status = KPROBE_HIT_SS;
888         return 1;
889 
890 no_kprobe:
891         preempt_enable_no_resched();
892         return ret;
893 }
894 
895 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
896 {
897         struct kprobe *cur = kprobe_running();
898         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
899 
900         if (!cur)
901                 return 0;
902 
903         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
904                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
905                 cur->post_handler(cur, regs, 0);
906         }
907 
908         resume_execution(cur, regs);
909 
910         /*Restore back the original saved kprobes variables and continue. */
911         if (kcb->kprobe_status == KPROBE_REENTER) {
912                 restore_previous_kprobe(kcb);
913                 goto out;
914         }
915         reset_current_kprobe();
916 
917 out:
918         preempt_enable_no_resched();
919         return 1;
920 }
921 
922 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
923 {
924         struct kprobe *cur = kprobe_running();
925         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
926 
927 
928         switch(kcb->kprobe_status) {
929         case KPROBE_HIT_SS:
930         case KPROBE_REENTER:
931                 /*
932                  * We are here because the instruction being single
933                  * stepped caused a page fault. We reset the current
934                  * kprobe and the instruction pointer points back to
935                  * the probe address and allow the page fault handler
936                  * to continue as a normal page fault.
937                  */
938                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
939                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
940                 if (kcb->kprobe_status == KPROBE_REENTER)
941                         restore_previous_kprobe(kcb);
942                 else
943                         reset_current_kprobe();
944                 preempt_enable_no_resched();
945                 break;
946         case KPROBE_HIT_ACTIVE:
947         case KPROBE_HIT_SSDONE:
948                 /*
949                  * We increment the nmissed count for accounting,
950                  * we can also use npre/npostfault count for accounting
951                  * these specific fault cases.
952                  */
953                 kprobes_inc_nmissed_count(cur);
954 
955                 /*
956                  * We come here because instructions in the pre/post
957                  * handler caused the page_fault, this could happen
958                  * if handler tries to access user space by
959                  * copy_from_user(), get_user() etc. Let the
960                  * user-specified handler try to fix it first.
961                  */
962                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
963                         return 1;
964                 /*
965                  * In case the user-specified fault handler returned
966                  * zero, try to fix up.
967                  */
968                 if (ia64_done_with_exception(regs))
969                         return 1;
970 
971                 /*
972                  * Let ia64_do_page_fault() fix it.
973                  */
974                 break;
975         default:
976                 break;
977         }
978 
979         return 0;
980 }
981 
982 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
983                                        unsigned long val, void *data)
984 {
985         struct die_args *args = (struct die_args *)data;
986         int ret = NOTIFY_DONE;
987 
988         if (args->regs && user_mode(args->regs))
989                 return ret;
990 
991         switch(val) {
992         case DIE_BREAK:
993                 /* err is break number from ia64_bad_break() */
994                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
995                         || args->err == __IA64_BREAK_JPROBE
996                         || args->err == 0)
997                         if (pre_kprobes_handler(args))
998                                 ret = NOTIFY_STOP;
999                 break;
1000         case DIE_FAULT:
1001                 /* err is vector number from ia64_fault() */
1002                 if (args->err == 36)
1003                         if (post_kprobes_handler(args->regs))
1004                                 ret = NOTIFY_STOP;
1005                 break;
1006         default:
1007                 break;
1008         }
1009         return ret;
1010 }
1011 
1012 struct param_bsp_cfm {
1013         unsigned long ip;
1014         unsigned long *bsp;
1015         unsigned long cfm;
1016 };
1017 
1018 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
1019 {
1020         unsigned long ip;
1021         struct param_bsp_cfm *lp = arg;
1022 
1023         do {
1024                 unw_get_ip(info, &ip);
1025                 if (ip == 0)
1026                         break;
1027                 if (ip == lp->ip) {
1028                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
1029                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
1030                         return;
1031                 }
1032         } while (unw_unwind(info) >= 0);
1033         lp->bsp = NULL;
1034         lp->cfm = 0;
1035         return;
1036 }
1037 
1038 unsigned long arch_deref_entry_point(void *entry)
1039 {
1040         return ((struct fnptr *)entry)->ip;
1041 }
1042 
1043 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
1044 {
1045         struct jprobe *jp = container_of(p, struct jprobe, kp);
1046         unsigned long addr = arch_deref_entry_point(jp->entry);
1047         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1048         struct param_bsp_cfm pa;
1049         int bytes;
1050 
1051         /*
1052          * Callee owns the argument space and could overwrite it, eg
1053          * tail call optimization. So to be absolutely safe
1054          * we save the argument space before transferring the control
1055          * to instrumented jprobe function which runs in
1056          * the process context
1057          */
1058         pa.ip = regs->cr_iip;
1059         unw_init_running(ia64_get_bsp_cfm, &pa);
1060         bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
1061                                 - (char *)pa.bsp;
1062         memcpy( kcb->jprobes_saved_stacked_regs,
1063                 pa.bsp,
1064                 bytes );
1065         kcb->bsp = pa.bsp;
1066         kcb->cfm = pa.cfm;
1067 
1068         /* save architectural state */
1069         kcb->jprobe_saved_regs = *regs;
1070 
1071         /* after rfi, execute the jprobe instrumented function */
1072         regs->cr_iip = addr & ~0xFULL;
1073         ia64_psr(regs)->ri = addr & 0xf;
1074         regs->r1 = ((struct fnptr *)(jp->entry))->gp;
1075 
1076         /*
1077          * fix the return address to our jprobe_inst_return() function
1078          * in the jprobes.S file
1079          */
1080         regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
1081 
1082         return 1;
1083 }
1084 
1085 /* ia64 does not need this */
1086 void __kprobes jprobe_return(void)
1087 {
1088 }
1089 
1090 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
1091 {
1092         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1093         int bytes;
1094 
1095         /* restoring architectural state */
1096         *regs = kcb->jprobe_saved_regs;
1097 
1098         /* restoring the original argument space */
1099         flush_register_stack();
1100         bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
1101                                 - (char *)kcb->bsp;
1102         memcpy( kcb->bsp,
1103                 kcb->jprobes_saved_stacked_regs,
1104                 bytes );
1105         invalidate_stacked_regs();
1106 
1107         preempt_enable_no_resched();
1108         return 1;
1109 }
1110 
1111 static struct kprobe trampoline_p = {
1112         .pre_handler = trampoline_probe_handler
1113 };
1114 
1115 int __init arch_init_kprobes(void)
1116 {
1117         trampoline_p.addr =
1118                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1119         return register_kprobe(&trampoline_p);
1120 }
1121 
1122 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1123 {
1124         if (p->addr ==
1125                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1126                 return 1;
1127 
1128         return 0;
1129 }
1130 

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