arch/ia64/kernel/kprobes.c

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