arch/ia64/kernel/kprobes.c

   1 /*
   2  *  Kernel Probes (KProbes)
   3  *  arch/ia64/kernel/kprobes.c
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  *
  19  * Copyright (C) IBM Corporation, 2002, 2004
  20  * Copyright (C) Intel Corporation, 2005
  21  *
  22  * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
  23  *              <anil.s.keshavamurthy@intel.com> adapted from i386
  24  */
  25
  26 #include <linux/kprobes.h>
  27 #include <linux/ptrace.h>
  28 #include <linux/string.h>
  29 #include <linux/slab.h>
  30 #include <linux/preempt.h>
  31 #include <linux/moduleloader.h>
  32 #include <linux/kdebug.h>
  33
  34 #include <asm/pgtable.h>
  35 #include <asm/sections.h>
  36 #include <asm/uaccess.h>
  37
  38 extern void jprobe_inst_return(void);
  39
  40 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
  41 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
  42
  43 struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
  44
  45 enum instruction_type {A, I, M, F, B, L, X, u};
  46 static enum instruction_type bundle_encoding[32][3] = {
  47   { M, I, I },                          /* 00 */
  48   { M, I, I },                          /* 01 */
  49   { M, I, I },                          /* 02 */
  50   { M, I, I },                          /* 03 */
  51   { M, L, X },                          /* 04 */
  52   { M, L, X },                          /* 05 */
  53   { u, u, u },                          /* 06 */
  54   { u, u, u },                          /* 07 */
  55   { M, M, I },                          /* 08 */
  56   { M, M, I },                          /* 09 */
  57   { M, M, I },                          /* 0A */
  58   { M, M, I },                          /* 0B */
  59   { M, F, I },                          /* 0C */
  60   { M, F, I },                          /* 0D */
  61   { M, M, F },                          /* 0E */
  62   { M, M, F },                          /* 0F */
  63   { M, I, B },                          /* 10 */
  64   { M, I, B },                          /* 11 */
  65   { M, B, B },                          /* 12 */
  66   { M, B, B },                          /* 13 */
  67   { u, u, u },                          /* 14 */
  68   { u, u, u },                          /* 15 */
  69   { B, B, B },                          /* 16 */
  70   { B, B, B },                          /* 17 */
  71   { M, M, B },                          /* 18 */
  72   { M, M, B },                          /* 19 */
  73   { u, u, u },                          /* 1A */
  74   { u, u, u },                          /* 1B */
  75   { M, F, B },                          /* 1C */
  76   { M, F, B },                          /* 1D */
  77   { u, u, u },                          /* 1E */
  78   { u, u, u },                          /* 1F */
  79 };
  80
  81 /*
  82  * In this function we check to see if the instruction
  83  * is IP relative instruction and update the kprobe
  84  * inst flag accordingly
  85  */
  86 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
  87                                               uint major_opcode,
  88                                               unsigned long kprobe_inst,
  89                                               struct kprobe *p)
  90 {
  91         p->ainsn.inst_flag = 0;
  92         p->ainsn.target_br_reg = 0;
  93         p->ainsn.slot = slot;
  94
  95         /* Check for Break instruction
  96          * Bits 37:40 Major opcode to be zero
  97          * Bits 27:32 X6 to be zero
  98          * Bits 32:35 X3 to be zero
  99          */
 100         if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
 101                 /* is a break instruction */
 102                 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
 103                 return;
 104         }
 105
 106         if (bundle_encoding[template][slot] == B) {
 107                 switch (major_opcode) {
 108                   case INDIRECT_CALL_OPCODE:
 109                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 110                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 111                         break;
 112                   case IP_RELATIVE_PREDICT_OPCODE:
 113                   case IP_RELATIVE_BRANCH_OPCODE:
 114                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 115                         break;
 116                   case IP_RELATIVE_CALL_OPCODE:
 117                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 118                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 119                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 120                         break;
 121                 }
 122         } else if (bundle_encoding[template][slot] == X) {
 123                 switch (major_opcode) {
 124                   case LONG_CALL_OPCODE:
 125                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 126                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 127                   break;
 128                 }
 129         }
 130         return;
 131 }
 132
 133 /*
 134  * In this function we check to see if the instruction
 135  * (qp) cmpx.crel.ctype p1,p2=r2,r3
 136  * on which we are inserting kprobe is cmp instruction
 137  * with ctype as unc.
 138  */
 139 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
 140                                             uint major_opcode,
 141                                             unsigned long kprobe_inst)
 142 {
 143         cmp_inst_t cmp_inst;
 144         uint ctype_unc = 0;
 145
 146         if (!((bundle_encoding[template][slot] == I) ||
 147                 (bundle_encoding[template][slot] == M)))
 148                 goto out;
 149
 150         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
 151                 (major_opcode == 0xE)))
 152                 goto out;
 153
 154         cmp_inst.l = kprobe_inst;
 155         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
 156                 /* Integer compare - Register Register (A6 type)*/
 157                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
 158                                 &&(cmp_inst.f.c == 1))
 159                         ctype_unc = 1;
 160         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
 161                 /* Integer compare - Immediate Register (A8 type)*/
 162                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
 163                         ctype_unc = 1;
 164         }
 165 out:
 166         return ctype_unc;
 167 }
 168
 169 /*
 170  * In this function we check to see if the instruction
 171  * on which we are inserting kprobe is supported.
 172  * Returns qp value if supported
 173  * Returns -EINVAL if unsupported
 174  */
 175 static int __kprobes unsupported_inst(uint template, uint  slot,
 176                                       uint major_opcode,
 177                                       unsigned long kprobe_inst,
 178                                       unsigned long addr)
 179 {
 180         int qp;
 181
 182         qp = kprobe_inst & 0x3f;
 183         if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
 184                 if (slot == 1 && qp)  {
 185                         printk(KERN_WARNING "Kprobes on cmp unc "
 186                                         "instruction on slot 1 at <0x%lx> "
 187                                         "is not supported\n", addr);
 188                         return -EINVAL;
 189
 190                 }
 191                 qp = 0;
 192         }
 193         else if (bundle_encoding[template][slot] == I) {
 194                 if (major_opcode == 0) {
 195                         /*
 196                          * Check for Integer speculation instruction
 197                          * - Bit 33-35 to be equal to 0x1
 198                          */
 199                         if (((kprobe_inst >> 33) & 0x7) == 1) {
 200                                 printk(KERN_WARNING
 201                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
 202                                                 addr);
 203                                 return -EINVAL;
 204                         }
 205                         /*
 206                          * IP relative mov instruction
 207                          *  - Bit 27-35 to be equal to 0x30
 208                          */
 209                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
 210                                 printk(KERN_WARNING
 211                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
 212                                                 addr);
 213                                 return -EINVAL;
 214
 215                         }
 216                 }
 217                 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
 218                                 (kprobe_inst & (0x1UL << 12))) {
 219                         /* test bit instructions, tbit,tnat,tf
 220                          * bit 33-36 to be equal to 0
 221                          * bit 12 to be equal to 1
 222                          */
 223                         if (slot == 1 && qp) {
 224                                 printk(KERN_WARNING "Kprobes on test bit "
 225                                                 "instruction on slot at <0x%lx> "
 226                                                 "is not supported\n", addr);
 227                                 return -EINVAL;
 228                         }
 229                         qp = 0;
 230                 }
 231         }
 232         else if (bundle_encoding[template][slot] == B) {
 233                 if (major_opcode == 7) {
 234                         /* IP-Relative Predict major code is 7 */
 235                         printk(KERN_WARNING "Kprobes on IP-Relative"
 236                                         "Predict is not supported\n");
 237                         return -EINVAL;
 238                 }
 239                 else if (major_opcode == 2) {
 240                         /* Indirect Predict, major code is 2
 241                          * bit 27-32 to be equal to 10 or 11
 242                          */
 243                         int x6=(kprobe_inst >> 27) & 0x3F;
 244                         if ((x6 == 0x10) || (x6 == 0x11)) {
 245                                 printk(KERN_WARNING "Kprobes on "
 246                                         "Indirect Predict is not supported\n");
 247                                 return -EINVAL;
 248                         }
 249                 }
 250         }
 251         /* kernel does not use float instruction, here for safety kprobe
 252          * will judge whether it is fcmp/flass/float approximation instruction
 253          */
 254         else if (unlikely(bundle_encoding[template][slot] == F)) {
 255                 if ((major_opcode == 4 || major_opcode == 5) &&
 256                                 (kprobe_inst  & (0x1 << 12))) {
 257                         /* fcmp/fclass unc instruction */
 258                         if (slot == 1 && qp) {
 259                                 printk(KERN_WARNING "Kprobes on fcmp/fclass "
 260                                         "instruction on slot at <0x%lx> "
 261                                         "is not supported\n", addr);
 262                                 return -EINVAL;
 263
 264                         }
 265                         qp = 0;
 266                 }
 267                 if ((major_opcode == 0 || major_opcode == 1) &&
 268                         (kprobe_inst & (0x1UL << 33))) {
 269                         /* float Approximation instruction */
 270                         if (slot == 1 && qp) {
 271                                 printk(KERN_WARNING "Kprobes on float Approx "
 272                                         "instr at <0x%lx> is not supported\n",
 273                                                 addr);
 274                                 return -EINVAL;
 275                         }
 276                         qp = 0;
 277                 }
 278         }
 279         return qp;
 280 }
 281
 282 /*
 283  * In this function we override the bundle with
 284  * the break instruction at the given slot.
 285  */
 286 static void __kprobes prepare_break_inst(uint template, uint  slot,
 287                                          uint major_opcode,
 288                                          unsigned long kprobe_inst,
 289                                          struct kprobe *p,
 290                                          int qp)
 291 {
 292         unsigned long break_inst = BREAK_INST;
 293         bundle_t *bundle = &p->opcode.bundle;
 294
 295         /*
 296          * Copy the original kprobe_inst qualifying predicate(qp)
 297          * to the break instruction
 298          */
 299         break_inst |= qp;
 300
 301         switch (slot) {
 302           case 0:
 303                 bundle->quad0.slot0 = break_inst;
 304                 break;
 305           case 1:
 306                 bundle->quad0.slot1_p0 = break_inst;
 307                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
 308                 break;
 309           case 2:
 310                 bundle->quad1.slot2 = break_inst;
 311                 break;
 312         }
 313
 314         /*
 315          * Update the instruction flag, so that we can
 316          * emulate the instruction properly after we
 317          * single step on original instruction
 318          */
 319         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
 320 }
 321
 322 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
 323                 unsigned long *kprobe_inst, uint *major_opcode)
 324 {
 325         unsigned long kprobe_inst_p0, kprobe_inst_p1;
 326         unsigned int template;
 327
 328         template = bundle->quad0.template;
 329
 330         switch (slot) {
 331           case 0:
 332                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
 333                 *kprobe_inst = bundle->quad0.slot0;
 334                   break;
 335           case 1:
 336                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
 337                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
 338                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
 339                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
 340                 break;
 341           case 2:
 342                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
 343                 *kprobe_inst = bundle->quad1.slot2;
 344                 break;
 345         }
 346 }
 347
 348 /* Returns non-zero if the addr is in the Interrupt Vector Table */
 349 static int __kprobes in_ivt_functions(unsigned long addr)
 350 {
 351         return (addr >= (unsigned long)__start_ivt_text
 352                 && addr < (unsigned long)__end_ivt_text);
 353 }
 354
 355 static int __kprobes valid_kprobe_addr(int template, int slot,
 356                                        unsigned long addr)
 357 {
 358         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
 359                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
 360                                 "at 0x%lx\n", addr);
 361                 return -EINVAL;
 362         }
 363
 364         if (in_ivt_functions(addr)) {
 365                 printk(KERN_WARNING "Kprobes can't be inserted inside "
 366                                 "IVT functions at 0x%lx\n", addr);
 367                 return -EINVAL;
 368         }
 369
 370         return 0;
 371 }
 372
 373 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
 374 {
 375         unsigned int i;
 376         i = atomic_add_return(1, &kcb->prev_kprobe_index);
 377         kcb->prev_kprobe[i-1].kp = kprobe_running();
 378         kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
 379 }
 380
 381 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 382 {
 383         unsigned int i;
 384         i = atomic_sub_return(1, &kcb->prev_kprobe_index);
 385         __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i].kp;
 386         kcb->kprobe_status = kcb->prev_kprobe[i].status;
 387 }
 388
 389 static void __kprobes set_current_kprobe(struct kprobe *p,
 390                         struct kprobe_ctlblk *kcb)
 391 {
 392         __get_cpu_var(current_kprobe) = p;
 393 }
 394
 395 static void kretprobe_trampoline(void)
 396 {
 397 }
 398
 399 /*
 400  * At this point the target function has been tricked into
 401  * returning into our trampoline.  Lookup the associated instance
 402  * and then:
 403  *    - call the handler function
 404  *    - cleanup by marking the instance as unused
 405  *    - long jump back to the original return address
 406  */
 407 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 408 {
 409         struct kretprobe_instance *ri = NULL;
 410         struct hlist_head *head, empty_rp;
 411         struct hlist_node *node, *tmp;
 412         unsigned long flags, orig_ret_address = 0;
 413         unsigned long trampoline_address =
 414                 ((struct fnptr *)kretprobe_trampoline)->ip;
 415
 416         INIT_HLIST_HEAD(&empty_rp);
 417         spin_lock_irqsave(&kretprobe_lock, flags);
 418         head = kretprobe_inst_table_head(current);
 419
 420         /*
 421          * It is possible to have multiple instances associated with a given
 422          * task either because an multiple functions in the call path
 423          * have a return probe installed on them, and/or more then one return
 424          * return probe was registered for a target function.
 425          *
 426          * We can handle this because:
 427          *     - instances are always inserted at the head of the list
 428          *     - when multiple return probes are registered for the same
 429          *       function, the first instance's ret_addr will point to the
 430          *       real return address, and all the rest will point to
 431          *       kretprobe_trampoline
 432          */
 433         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
 434                 if (ri->task != current)
 435                         /* another task is sharing our hash bucket */
 436                         continue;
 437
 438                 orig_ret_address = (unsigned long)ri->ret_addr;
 439                 if (orig_ret_address != trampoline_address)
 440                         /*
 441                          * This is the real return address. Any other
 442                          * instances associated with this task are for
 443                          * other calls deeper on the call stack
 444                          */
 445                         break;
 446         }
 447
 448         regs->cr_iip = orig_ret_address;
 449
 450         hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
 451                 if (ri->task != current)
 452                         /* another task is sharing our hash bucket */
 453                         continue;
 454
 455                 if (ri->rp && ri->rp->handler)
 456                         ri->rp->handler(ri, regs);
 457
 458                 orig_ret_address = (unsigned long)ri->ret_addr;
 459                 recycle_rp_inst(ri, &empty_rp);
 460
 461                 if (orig_ret_address != trampoline_address)
 462                         /*
 463                          * This is the real return address. Any other
 464                          * instances associated with this task are for
 465                          * other calls deeper on the call stack
 466                          */
 467                         break;
 468         }
 469
 470         kretprobe_assert(ri, orig_ret_address, trampoline_address);
 471
 472         reset_current_kprobe();
 473         spin_unlock_irqrestore(&kretprobe_lock, flags);
 474         preempt_enable_no_resched();
 475
 476         hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
 477                 hlist_del(&ri->hlist);
 478                 kfree(ri);
 479         }
 480         /*
 481          * By returning a non-zero value, we are telling
 482          * kprobe_handler() that we don't want the post_handler
 483          * to run (and have re-enabled preemption)
 484          */
 485         return 1;
 486 }
 487
 488 /* Called with kretprobe_lock held */
 489 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 490                                       struct pt_regs *regs)
 491 {
 492         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
 493
 494         /* Replace the return addr with trampoline addr */
 495         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
 496 }
 497
 498 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 499 {
 500         unsigned long addr = (unsigned long) p->addr;
 501         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
 502         unsigned long kprobe_inst=0;
 503         unsigned int slot = addr & 0xf, template, major_opcode = 0;
 504         bundle_t *bundle;
 505         int qp;
 506
 507         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
 508         template = bundle->quad0.template;
 509
 510         if(valid_kprobe_addr(template, slot, addr))
 511                 return -EINVAL;
 512
 513         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 514         if (slot == 1 && bundle_encoding[template][1] == L)
 515                 slot++;
 516
 517         /* Get kprobe_inst and major_opcode from the bundle */
 518         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 519
 520         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
 521         if (qp < 0)
 522                 return -EINVAL;
 523
 524         p->ainsn.insn = get_insn_slot();
 525         if (!p->ainsn.insn)
 526                 return -ENOMEM;
 527         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
 528         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
 529
 530         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
 531
 532         return 0;
 533 }
 534
 535 void __kprobes arch_arm_kprobe(struct kprobe *p)
 536 {
 537         unsigned long arm_addr;
 538         bundle_t *src, *dest;
 539
 540         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 541         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 542         src = &p->opcode.bundle;
 543
 544         flush_icache_range((unsigned long)p->ainsn.insn,
 545                         (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
 546         switch (p->ainsn.slot) {
 547                 case 0:
 548                         dest->quad0.slot0 = src->quad0.slot0;
 549                         break;
 550                 case 1:
 551                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 552                         break;
 553                 case 2:
 554                         dest->quad1.slot2 = src->quad1.slot2;
 555                         break;
 556         }
 557         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 558 }
 559
 560 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 561 {
 562         unsigned long arm_addr;
 563         bundle_t *src, *dest;
 564
 565         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 566         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 567         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
 568         src = &p->ainsn.insn->bundle;
 569         switch (p->ainsn.slot) {
 570                 case 0:
 571                         dest->quad0.slot0 = src->quad0.slot0;
 572                         break;
 573                 case 1:
 574                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 575                         break;
 576                 case 2:
 577                         dest->quad1.slot2 = src->quad1.slot2;
 578                         break;
 579         }
 580         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 581 }
 582
 583 void __kprobes arch_remove_kprobe(struct kprobe *p)
 584 {
 585         mutex_lock(&kprobe_mutex);
 586         free_insn_slot(p->ainsn.insn, 0);
 587         mutex_unlock(&kprobe_mutex);
 588 }
 589 /*
 590  * We are resuming execution after a single step fault, so the pt_regs
 591  * structure reflects the register state after we executed the instruction
 592  * located in the kprobe (p->ainsn.insn.bundle).  We still need to adjust
 593  * the ip to point back to the original stack address. To set the IP address
 594  * to original stack address, handle the case where we need to fixup the
 595  * relative IP address and/or fixup branch register.
 596  */
 597 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 598 {
 599         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
 600         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
 601         unsigned long template;
 602         int slot = ((unsigned long)p->addr & 0xf);
 603
 604         template = p->ainsn.insn->bundle.quad0.template;
 605
 606         if (slot == 1 && bundle_encoding[template][1] == L)
 607                 slot = 2;
 608
 609         if (p->ainsn.inst_flag) {
 610
 611                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
 612                         /* Fix relative IP address */
 613                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
 614                                         resume_addr;
 615                 }
 616
 617                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
 618                 /*
 619                  * Fix target branch register, software convention is
 620                  * to use either b0 or b6 or b7, so just checking
 621                  * only those registers
 622                  */
 623                         switch (p->ainsn.target_br_reg) {
 624                         case 0:
 625                                 if ((regs->b0 == bundle_addr) ||
 626                                         (regs->b0 == bundle_addr + 0x10)) {
 627                                         regs->b0 = (regs->b0 - bundle_addr) +
 628                                                 resume_addr;
 629                                 }
 630                                 break;
 631                         case 6:
 632                                 if ((regs->b6 == bundle_addr) ||
 633                                         (regs->b6 == bundle_addr + 0x10)) {
 634                                         regs->b6 = (regs->b6 - bundle_addr) +
 635                                                 resume_addr;
 636                                 }
 637                                 break;
 638                         case 7:
 639                                 if ((regs->b7 == bundle_addr) ||
 640                                         (regs->b7 == bundle_addr + 0x10)) {
 641                                         regs->b7 = (regs->b7 - bundle_addr) +
 642                                                 resume_addr;
 643                                 }
 644                                 break;
 645                         } /* end switch */
 646                 }
 647                 goto turn_ss_off;
 648         }
 649
 650         if (slot == 2) {
 651                 if (regs->cr_iip == bundle_addr + 0x10) {
 652                         regs->cr_iip = resume_addr + 0x10;
 653                 }
 654         } else {
 655                 if (regs->cr_iip == bundle_addr) {
 656                         regs->cr_iip = resume_addr;
 657                 }
 658         }
 659
 660 turn_ss_off:
 661         /* Turn off Single Step bit */
 662         ia64_psr(regs)->ss = 0;
 663 }
 664
 665 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
 666 {
 667         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
 668         unsigned long slot = (unsigned long)p->addr & 0xf;
 669
 670         /* single step inline if break instruction */
 671         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
 672                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
 673         else
 674                 regs->cr_iip = bundle_addr & ~0xFULL;
 675
 676         if (slot > 2)
 677                 slot = 0;
 678
 679         ia64_psr(regs)->ri = slot;
 680
 681         /* turn on single stepping */
 682         ia64_psr(regs)->ss = 1;
 683 }
 684
 685 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
 686 {
 687         unsigned int slot = ia64_psr(regs)->ri;
 688         unsigned int template, major_opcode;
 689         unsigned long kprobe_inst;
 690         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
 691         bundle_t bundle;
 692
 693         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
 694         template = bundle.quad0.template;
 695
 696         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 697         if (slot == 1 && bundle_encoding[template][1] == L)
 698                 slot++;
 699
 700         /* Get Kprobe probe instruction at given slot*/
 701         get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode);
 702
 703         /* For break instruction,
 704          * Bits 37:40 Major opcode to be zero
 705          * Bits 27:32 X6 to be zero
 706          * Bits 32:35 X3 to be zero
 707          */
 708         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) {
 709                 /* Not a break instruction */
 710                 return 0;
 711         }
 712
 713         /* Is a break instruction */
 714         return 1;
 715 }
 716
 717 static int __kprobes pre_kprobes_handler(struct die_args *args)
 718 {
 719         struct kprobe *p;
 720         int ret = 0;
 721         struct pt_regs *regs = args->regs;
 722         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 723         struct kprobe_ctlblk *kcb;
 724
 725         /*
 726          * We don't want to be preempted for the entire
 727          * duration of kprobe processing
 728          */
 729         preempt_disable();
 730         kcb = get_kprobe_ctlblk();
 731
 732         /* Handle recursion cases */
 733         if (kprobe_running()) {
 734                 p = get_kprobe(addr);
 735                 if (p) {
 736                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
 737                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
 738                                 ia64_psr(regs)->ss = 0;
 739                                 goto no_kprobe;
 740                         }
 741                         /* We have reentered the pre_kprobe_handler(), since
 742                          * another probe was hit while within the handler.
 743                          * We here save the original kprobes variables and
 744                          * just single step on the instruction of the new probe
 745                          * without calling any user handlers.
 746                          */
 747                         save_previous_kprobe(kcb);
 748                         set_current_kprobe(p, kcb);
 749                         kprobes_inc_nmissed_count(p);
 750                         prepare_ss(p, regs);
 751                         kcb->kprobe_status = KPROBE_REENTER;
 752                         return 1;
 753                 } else if (args->err == __IA64_BREAK_JPROBE) {
 754                         /*
 755                          * jprobe instrumented function just completed
 756                          */
 757                         p = __get_cpu_var(current_kprobe);
 758                         if (p->break_handler && p->break_handler(p, regs)) {
 759                                 goto ss_probe;
 760                         }
 761                 } else if (!is_ia64_break_inst(regs)) {
 762                         /* The breakpoint instruction was removed by
 763                          * another cpu right after we hit, no further
 764                          * handling of this interrupt is appropriate
 765                          */
 766                         ret = 1;
 767                         goto no_kprobe;
 768                 } else {
 769                         /* Not our break */
 770                         goto no_kprobe;
 771                 }
 772         }
 773
 774         p = get_kprobe(addr);
 775         if (!p) {
 776                 if (!is_ia64_break_inst(regs)) {
 777                         /*
 778                          * The breakpoint instruction was removed right
 779                          * after we hit it.  Another cpu has removed
 780                          * either a probepoint or a debugger breakpoint
 781                          * at this address.  In either case, no further
 782                          * handling of this interrupt is appropriate.
 783                          */
 784                         ret = 1;
 785
 786                 }
 787
 788                 /* Not one of our break, let kernel handle it */
 789                 goto no_kprobe;
 790         }
 791
 792         set_current_kprobe(p, kcb);
 793         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 794
 795         if (p->pre_handler && p->pre_handler(p, regs))
 796                 /*
 797                  * Our pre-handler is specifically requesting that we just
 798                  * do a return.  This is used for both the jprobe pre-handler
 799                  * and the kretprobe trampoline
 800                  */
 801                 return 1;
 802
 803 ss_probe:
 804         prepare_ss(p, regs);
 805         kcb->kprobe_status = KPROBE_HIT_SS;
 806         return 1;
 807
 808 no_kprobe:
 809         preempt_enable_no_resched();
 810         return ret;
 811 }
 812
 813 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
 814 {
 815         struct kprobe *cur = kprobe_running();
 816         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 817
 818         if (!cur)
 819                 return 0;
 820
 821         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
 822                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
 823                 cur->post_handler(cur, regs, 0);
 824         }
 825
 826         resume_execution(cur, regs);
 827
 828         /*Restore back the original saved kprobes variables and continue. */
 829         if (kcb->kprobe_status == KPROBE_REENTER) {
 830                 restore_previous_kprobe(kcb);
 831                 goto out;
 832         }
 833         reset_current_kprobe();
 834
 835 out:
 836         preempt_enable_no_resched();
 837         return 1;
 838 }
 839
 840 int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
 841 {
 842         struct kprobe *cur = kprobe_running();
 843         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 844
 845
 846         switch(kcb->kprobe_status) {
 847         case KPROBE_HIT_SS:
 848         case KPROBE_REENTER:
 849                 /*
 850                  * We are here because the instruction being single
 851                  * stepped caused a page fault. We reset the current
 852                  * kprobe and the instruction pointer points back to
 853                  * the probe address and allow the page fault handler
 854                  * to continue as a normal page fault.
 855                  */
 856                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
 857                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
 858                 if (kcb->kprobe_status == KPROBE_REENTER)
 859                         restore_previous_kprobe(kcb);
 860                 else
 861                         reset_current_kprobe();
 862                 preempt_enable_no_resched();
 863                 break;
 864         case KPROBE_HIT_ACTIVE:
 865         case KPROBE_HIT_SSDONE:
 866                 /*
 867                  * We increment the nmissed count for accounting,
 868                  * we can also use npre/npostfault count for accouting
 869                  * these specific fault cases.
 870                  */
 871                 kprobes_inc_nmissed_count(cur);
 872
 873                 /*
 874                  * We come here because instructions in the pre/post
 875                  * handler caused the page_fault, this could happen
 876                  * if handler tries to access user space by
 877                  * copy_from_user(), get_user() etc. Let the
 878                  * user-specified handler try to fix it first.
 879                  */
 880                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
 881                         return 1;
 882                 /*
 883                  * In case the user-specified fault handler returned
 884                  * zero, try to fix up.
 885                  */
 886                 if (ia64_done_with_exception(regs))
 887                         return 1;
 888
 889                 /*
 890                  * Let ia64_do_page_fault() fix it.
 891                  */
 892                 break;
 893         default:
 894                 break;
 895         }
 896
 897         return 0;
 898 }
 899
 900 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 901                                        unsigned long val, void *data)
 902 {
 903         struct die_args *args = (struct die_args *)data;
 904         int ret = NOTIFY_DONE;
 905
 906         if (args->regs && user_mode(args->regs))
 907                 return ret;
 908
 909         switch(val) {
 910         case DIE_BREAK:
 911                 /* err is break number from ia64_bad_break() */
 912                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
 913                         || args->err == __IA64_BREAK_JPROBE
 914                         || args->err == 0)
 915                         if (pre_kprobes_handler(args))
 916                                 ret = NOTIFY_STOP;
 917                 break;
 918         case DIE_FAULT:
 919                 /* err is vector number from ia64_fault() */
 920                 if (args->err == 36)
 921                         if (post_kprobes_handler(args->regs))
 922                                 ret = NOTIFY_STOP;
 923                 break;
 924         default:
 925                 break;
 926         }
 927         return ret;
 928 }
 929
 930 struct param_bsp_cfm {
 931         unsigned long ip;
 932         unsigned long *bsp;
 933         unsigned long cfm;
 934 };
 935
 936 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
 937 {
 938         unsigned long ip;
 939         struct param_bsp_cfm *lp = arg;
 940
 941         do {
 942                 unw_get_ip(info, &ip);
 943                 if (ip == 0)
 944                         break;
 945                 if (ip == lp->ip) {
 946                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
 947                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
 948                         return;
 949                 }
 950         } while (unw_unwind(info) >= 0);
 951         lp->bsp = NULL;
 952         lp->cfm = 0;
 953         return;
 954 }
 955
 956 unsigned long arch_deref_entry_point(void *entry)
 957 {
 958         return ((struct fnptr *)entry)->ip;
 959 }
 960
 961 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 962 {
 963         struct jprobe *jp = container_of(p, struct jprobe, kp);
 964         unsigned long addr = arch_deref_entry_point(jp->entry);
 965         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 966         struct param_bsp_cfm pa;
 967         int bytes;
 968
 969         /*
 970          * Callee owns the argument space and could overwrite it, eg
 971          * tail call optimization. So to be absolutely safe
 972          * we save the argument space before transferring the control
 973          * to instrumented jprobe function which runs in
 974          * the process context
 975          */
 976         pa.ip = regs->cr_iip;
 977         unw_init_running(ia64_get_bsp_cfm, &pa);
 978         bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
 979                                 - (char *)pa.bsp;
 980         memcpy( kcb->jprobes_saved_stacked_regs,
 981                 pa.bsp,
 982                 bytes );
 983         kcb->bsp = pa.bsp;
 984         kcb->cfm = pa.cfm;
 985
 986         /* save architectural state */
 987         kcb->jprobe_saved_regs = *regs;
 988
 989         /* after rfi, execute the jprobe instrumented function */
 990         regs->cr_iip = addr & ~0xFULL;
 991         ia64_psr(regs)->ri = addr & 0xf;
 992         regs->r1 = ((struct fnptr *)(jp->entry))->gp;
 993
 994         /*
 995          * fix the return address to our jprobe_inst_return() function
 996          * in the jprobes.S file
 997          */
 998         regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
 999
1000         return 1;
1001 }
1002
1003 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
1004 {
1005         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1006         int bytes;
1007
1008         /* restoring architectural state */
1009         *regs = kcb->jprobe_saved_regs;
1010
1011         /* restoring the original argument space */
1012         flush_register_stack();
1013         bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
1014                                 - (char *)kcb->bsp;
1015         memcpy( kcb->bsp,
1016                 kcb->jprobes_saved_stacked_regs,
1017                 bytes );
1018         invalidate_stacked_regs();
1019
1020         preempt_enable_no_resched();
1021         return 1;
1022 }
1023
1024 static struct kprobe trampoline_p = {
1025         .pre_handler = trampoline_probe_handler
1026 };
1027
1028 int __init arch_init_kprobes(void)
1029 {
1030         trampoline_p.addr =
1031                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1032         return register_kprobe(&trampoline_p);
1033 }
1034
1035 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1036 {
1037         if (p->addr ==
1038                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1039                 return 1;
1040
1041         return 0;
1042 }