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/extable.h>
  32 #include <linux/kdebug.h>
  33
  34 #include <asm/pgtable.h>
  35 #include <asm/sections.h>
  36 #include <asm/exception.h>
  37
  38 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
  39 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
  40
  41 struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
  42
  43 enum instruction_type {A, I, M, F, B, L, X, u};
  44 static enum instruction_type bundle_encoding[32][3] = {
  45   { M, I, I },                          /* 00 */
  46   { M, I, I },                          /* 01 */
  47   { M, I, I },                          /* 02 */
  48   { M, I, I },                          /* 03 */
  49   { M, L, X },                          /* 04 */
  50   { M, L, X },                          /* 05 */
  51   { u, u, u },                          /* 06 */
  52   { u, u, u },                          /* 07 */
  53   { M, M, I },                          /* 08 */
  54   { M, M, I },                          /* 09 */
  55   { M, M, I },                          /* 0A */
  56   { M, M, I },                          /* 0B */
  57   { M, F, I },                          /* 0C */
  58   { M, F, I },                          /* 0D */
  59   { M, M, F },                          /* 0E */
  60   { M, M, F },                          /* 0F */
  61   { M, I, B },                          /* 10 */
  62   { M, I, B },                          /* 11 */
  63   { M, B, B },                          /* 12 */
  64   { M, B, B },                          /* 13 */
  65   { u, u, u },                          /* 14 */
  66   { u, u, u },                          /* 15 */
  67   { B, B, B },                          /* 16 */
  68   { B, B, B },                          /* 17 */
  69   { M, M, B },                          /* 18 */
  70   { M, M, B },                          /* 19 */
  71   { u, u, u },                          /* 1A */
  72   { u, u, u },                          /* 1B */
  73   { M, F, B },                          /* 1C */
  74   { M, F, B },                          /* 1D */
  75   { u, u, u },                          /* 1E */
  76   { u, u, u },                          /* 1F */
  77 };
  78
  79 /* Insert a long branch code */
  80 static void __kprobes set_brl_inst(void *from, void *to)
  81 {
  82         s64 rel = ((s64) to - (s64) from) >> 4;
  83         bundle_t *brl;
  84         brl = (bundle_t *) ((u64) from & ~0xf);
  85         brl->quad0.template = 0x05;     /* [MLX](stop) */
  86         brl->quad0.slot0 = NOP_M_INST;  /* nop.m 0x0 */
  87         brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
  88         brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
  89         /* brl.cond.sptk.many.clr rel<<4 (qp=0) */
  90         brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
  91 }
  92
  93 /*
  94  * In this function we check to see if the instruction
  95  * is IP relative instruction and update the kprobe
  96  * inst flag accordingly
  97  */
  98 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
  99                                               uint major_opcode,
 100                                               unsigned long kprobe_inst,
 101                                               struct kprobe *p)
 102 {
 103         p->ainsn.inst_flag = 0;
 104         p->ainsn.target_br_reg = 0;
 105         p->ainsn.slot = slot;
 106
 107         /* Check for Break instruction
 108          * Bits 37:40 Major opcode to be zero
 109          * Bits 27:32 X6 to be zero
 110          * Bits 32:35 X3 to be zero
 111          */
 112         if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
 113                 /* is a break instruction */
 114                 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
 115                 return;
 116         }
 117
 118         if (bundle_encoding[template][slot] == B) {
 119                 switch (major_opcode) {
 120                   case INDIRECT_CALL_OPCODE:
 121                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 122                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 123                         break;
 124                   case IP_RELATIVE_PREDICT_OPCODE:
 125                   case IP_RELATIVE_BRANCH_OPCODE:
 126                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 127                         break;
 128                   case IP_RELATIVE_CALL_OPCODE:
 129                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 130                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 131                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 132                         break;
 133                 }
 134         } else if (bundle_encoding[template][slot] == X) {
 135                 switch (major_opcode) {
 136                   case LONG_CALL_OPCODE:
 137                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 138                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 139                   break;
 140                 }
 141         }
 142         return;
 143 }
 144
 145 /*
 146  * In this function we check to see if the instruction
 147  * (qp) cmpx.crel.ctype p1,p2=r2,r3
 148  * on which we are inserting kprobe is cmp instruction
 149  * with ctype as unc.
 150  */
 151 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
 152                                             uint major_opcode,
 153                                             unsigned long kprobe_inst)
 154 {
 155         cmp_inst_t cmp_inst;
 156         uint ctype_unc = 0;
 157
 158         if (!((bundle_encoding[template][slot] == I) ||
 159                 (bundle_encoding[template][slot] == M)))
 160                 goto out;
 161
 162         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
 163                 (major_opcode == 0xE)))
 164                 goto out;
 165
 166         cmp_inst.l = kprobe_inst;
 167         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
 168                 /* Integer compare - Register Register (A6 type)*/
 169                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
 170                                 &&(cmp_inst.f.c == 1))
 171                         ctype_unc = 1;
 172         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
 173                 /* Integer compare - Immediate Register (A8 type)*/
 174                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
 175                         ctype_unc = 1;
 176         }
 177 out:
 178         return ctype_unc;
 179 }
 180
 181 /*
 182  * In this function we check to see if the instruction
 183  * on which we are inserting kprobe is supported.
 184  * Returns qp value if supported
 185  * Returns -EINVAL if unsupported
 186  */
 187 static int __kprobes unsupported_inst(uint template, uint  slot,
 188                                       uint major_opcode,
 189                                       unsigned long kprobe_inst,
 190                                       unsigned long addr)
 191 {
 192         int qp;
 193
 194         qp = kprobe_inst & 0x3f;
 195         if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
 196                 if (slot == 1 && qp)  {
 197                         printk(KERN_WARNING "Kprobes on cmp unc "
 198                                         "instruction on slot 1 at <0x%lx> "
 199                                         "is not supported\n", addr);
 200                         return -EINVAL;
 201
 202                 }
 203                 qp = 0;
 204         }
 205         else if (bundle_encoding[template][slot] == I) {
 206                 if (major_opcode == 0) {
 207                         /*
 208                          * Check for Integer speculation instruction
 209                          * - Bit 33-35 to be equal to 0x1
 210                          */
 211                         if (((kprobe_inst >> 33) & 0x7) == 1) {
 212                                 printk(KERN_WARNING
 213                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
 214                                                 addr);
 215                                 return -EINVAL;
 216                         }
 217                         /*
 218                          * IP relative mov instruction
 219                          *  - Bit 27-35 to be equal to 0x30
 220                          */
 221                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
 222                                 printk(KERN_WARNING
 223                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
 224                                                 addr);
 225                                 return -EINVAL;
 226
 227                         }
 228                 }
 229                 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
 230                                 (kprobe_inst & (0x1UL << 12))) {
 231                         /* test bit instructions, tbit,tnat,tf
 232                          * bit 33-36 to be equal to 0
 233                          * bit 12 to be equal to 1
 234                          */
 235                         if (slot == 1 && qp) {
 236                                 printk(KERN_WARNING "Kprobes on test bit "
 237                                                 "instruction on slot at <0x%lx> "
 238                                                 "is not supported\n", addr);
 239                                 return -EINVAL;
 240                         }
 241                         qp = 0;
 242                 }
 243         }
 244         else if (bundle_encoding[template][slot] == B) {
 245                 if (major_opcode == 7) {
 246                         /* IP-Relative Predict major code is 7 */
 247                         printk(KERN_WARNING "Kprobes on IP-Relative"
 248                                         "Predict is not supported\n");
 249                         return -EINVAL;
 250                 }
 251                 else if (major_opcode == 2) {
 252                         /* Indirect Predict, major code is 2
 253                          * bit 27-32 to be equal to 10 or 11
 254                          */
 255                         int x6=(kprobe_inst >> 27) & 0x3F;
 256                         if ((x6 == 0x10) || (x6 == 0x11)) {
 257                                 printk(KERN_WARNING "Kprobes on "
 258                                         "Indirect Predict is not supported\n");
 259                                 return -EINVAL;
 260                         }
 261                 }
 262         }
 263         /* kernel does not use float instruction, here for safety kprobe
 264          * will judge whether it is fcmp/flass/float approximation instruction
 265          */
 266         else if (unlikely(bundle_encoding[template][slot] == F)) {
 267                 if ((major_opcode == 4 || major_opcode == 5) &&
 268                                 (kprobe_inst  & (0x1 << 12))) {
 269                         /* fcmp/fclass unc instruction */
 270                         if (slot == 1 && qp) {
 271                                 printk(KERN_WARNING "Kprobes on fcmp/fclass "
 272                                         "instruction on slot at <0x%lx> "
 273                                         "is not supported\n", addr);
 274                                 return -EINVAL;
 275
 276                         }
 277                         qp = 0;
 278                 }
 279                 if ((major_opcode == 0 || major_opcode == 1) &&
 280                         (kprobe_inst & (0x1UL << 33))) {
 281                         /* float Approximation instruction */
 282                         if (slot == 1 && qp) {
 283                                 printk(KERN_WARNING "Kprobes on float Approx "
 284                                         "instr at <0x%lx> is not supported\n",
 285                                                 addr);
 286                                 return -EINVAL;
 287                         }
 288                         qp = 0;
 289                 }
 290         }
 291         return qp;
 292 }
 293
 294 /*
 295  * In this function we override the bundle with
 296  * the break instruction at the given slot.
 297  */
 298 static void __kprobes prepare_break_inst(uint template, uint  slot,
 299                                          uint major_opcode,
 300                                          unsigned long kprobe_inst,
 301                                          struct kprobe *p,
 302                                          int qp)
 303 {
 304         unsigned long break_inst = BREAK_INST;
 305         bundle_t *bundle = &p->opcode.bundle;
 306
 307         /*
 308          * Copy the original kprobe_inst qualifying predicate(qp)
 309          * to the break instruction
 310          */
 311         break_inst |= qp;
 312
 313         switch (slot) {
 314           case 0:
 315                 bundle->quad0.slot0 = break_inst;
 316                 break;
 317           case 1:
 318                 bundle->quad0.slot1_p0 = break_inst;
 319                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
 320                 break;
 321           case 2:
 322                 bundle->quad1.slot2 = break_inst;
 323                 break;
 324         }
 325
 326         /*
 327          * Update the instruction flag, so that we can
 328          * emulate the instruction properly after we
 329          * single step on original instruction
 330          */
 331         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
 332 }
 333
 334 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
 335                 unsigned long *kprobe_inst, uint *major_opcode)
 336 {
 337         unsigned long kprobe_inst_p0, kprobe_inst_p1;
 338         unsigned int template;
 339
 340         template = bundle->quad0.template;
 341
 342         switch (slot) {
 343           case 0:
 344                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
 345                 *kprobe_inst = bundle->quad0.slot0;
 346                   break;
 347           case 1:
 348                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
 349                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
 350                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
 351                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
 352                 break;
 353           case 2:
 354                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
 355                 *kprobe_inst = bundle->quad1.slot2;
 356                 break;
 357         }
 358 }
 359
 360 /* Returns non-zero if the addr is in the Interrupt Vector Table */
 361 static int __kprobes in_ivt_functions(unsigned long addr)
 362 {
 363         return (addr >= (unsigned long)__start_ivt_text
 364                 && addr < (unsigned long)__end_ivt_text);
 365 }
 366
 367 static int __kprobes valid_kprobe_addr(int template, int slot,
 368                                        unsigned long addr)
 369 {
 370         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
 371                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
 372                                 "at 0x%lx\n", addr);
 373                 return -EINVAL;
 374         }
 375
 376         if (in_ivt_functions(addr)) {
 377                 printk(KERN_WARNING "Kprobes can't be inserted inside "
 378                                 "IVT functions at 0x%lx\n", addr);
 379                 return -EINVAL;
 380         }
 381
 382         return 0;
 383 }
 384
 385 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
 386 {
 387         unsigned int i;
 388         i = atomic_add_return(1, &kcb->prev_kprobe_index);
 389         kcb->prev_kprobe[i-1].kp = kprobe_running();
 390         kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
 391 }
 392
 393 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 394 {
 395         unsigned int i;
 396         i = atomic_read(&kcb->prev_kprobe_index);
 397         __this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp);
 398         kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
 399         atomic_sub(1, &kcb->prev_kprobe_index);
 400 }
 401
 402 static void __kprobes set_current_kprobe(struct kprobe *p,
 403                         struct kprobe_ctlblk *kcb)
 404 {
 405         __this_cpu_write(current_kprobe, p);
 406 }
 407
 408 static void kretprobe_trampoline(void)
 409 {
 410 }
 411
 412 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 413 {
 414         regs->cr_iip = __kretprobe_trampoline_handler(regs, kretprobe_trampoline, NULL);
 415         /*
 416          * By returning a non-zero value, we are telling
 417          * kprobe_handler() that we don't want the post_handler
 418          * to run (and have re-enabled preemption)
 419          */
 420         return 1;
 421 }
 422
 423 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 424                                       struct pt_regs *regs)
 425 {
 426         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
 427         ri->fp = NULL;
 428
 429         /* Replace the return addr with trampoline addr */
 430         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
 431 }
 432
 433 /* Check the instruction in the slot is break */
 434 static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
 435 {
 436         unsigned int major_opcode;
 437         unsigned int template = bundle->quad0.template;
 438         unsigned long kprobe_inst;
 439
 440         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 441         if (slot == 1 && bundle_encoding[template][1] == L)
 442                 slot++;
 443
 444         /* Get Kprobe probe instruction at given slot*/
 445         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 446
 447         /* For break instruction,
 448          * Bits 37:40 Major opcode to be zero
 449          * Bits 27:32 X6 to be zero
 450          * Bits 32:35 X3 to be zero
 451          */
 452         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
 453                 /* Not a break instruction */
 454                 return 0;
 455         }
 456
 457         /* Is a break instruction */
 458         return 1;
 459 }
 460
 461 /*
 462  * In this function, we check whether the target bundle modifies IP or
 463  * it triggers an exception. If so, it cannot be boostable.
 464  */
 465 static int __kprobes can_boost(bundle_t *bundle, uint slot,
 466                                unsigned long bundle_addr)
 467 {
 468         unsigned int template = bundle->quad0.template;
 469
 470         do {
 471                 if (search_exception_tables(bundle_addr + slot) ||
 472                     __is_ia64_break_inst(bundle, slot))
 473                         return 0;       /* exception may occur in this bundle*/
 474         } while ((++slot) < 3);
 475         template &= 0x1e;
 476         if (template >= 0x10 /* including B unit */ ||
 477             template == 0x04 /* including X unit */ ||
 478             template == 0x06) /* undefined */
 479                 return 0;
 480
 481         return 1;
 482 }
 483
 484 /* Prepare long jump bundle and disables other boosters if need */
 485 static void __kprobes prepare_booster(struct kprobe *p)
 486 {
 487         unsigned long addr = (unsigned long)p->addr & ~0xFULL;
 488         unsigned int slot = (unsigned long)p->addr & 0xf;
 489         struct kprobe *other_kp;
 490
 491         if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
 492                 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
 493                 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
 494         }
 495
 496         /* disables boosters in previous slots */
 497         for (; addr < (unsigned long)p->addr; addr++) {
 498                 other_kp = get_kprobe((void *)addr);
 499                 if (other_kp)
 500                         other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
 501         }
 502 }
 503
 504 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 505 {
 506         unsigned long addr = (unsigned long) p->addr;
 507         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
 508         unsigned long kprobe_inst=0;
 509         unsigned int slot = addr & 0xf, template, major_opcode = 0;
 510         bundle_t *bundle;
 511         int qp;
 512
 513         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
 514         template = bundle->quad0.template;
 515
 516         if(valid_kprobe_addr(template, slot, addr))
 517                 return -EINVAL;
 518
 519         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 520         if (slot == 1 && bundle_encoding[template][1] == L)
 521                 slot++;
 522
 523         /* Get kprobe_inst and major_opcode from the bundle */
 524         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 525
 526         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
 527         if (qp < 0)
 528                 return -EINVAL;
 529
 530         p->ainsn.insn = get_insn_slot();
 531         if (!p->ainsn.insn)
 532                 return -ENOMEM;
 533         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
 534         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
 535
 536         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
 537
 538         prepare_booster(p);
 539
 540         return 0;
 541 }
 542
 543 void __kprobes arch_arm_kprobe(struct kprobe *p)
 544 {
 545         unsigned long arm_addr;
 546         bundle_t *src, *dest;
 547
 548         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 549         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 550         src = &p->opcode.bundle;
 551
 552         flush_icache_range((unsigned long)p->ainsn.insn,
 553                            (unsigned long)p->ainsn.insn +
 554                            sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
 555
 556         switch (p->ainsn.slot) {
 557                 case 0:
 558                         dest->quad0.slot0 = src->quad0.slot0;
 559                         break;
 560                 case 1:
 561                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 562                         break;
 563                 case 2:
 564                         dest->quad1.slot2 = src->quad1.slot2;
 565                         break;
 566         }
 567         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 568 }
 569
 570 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 571 {
 572         unsigned long arm_addr;
 573         bundle_t *src, *dest;
 574
 575         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 576         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 577         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
 578         src = &p->ainsn.insn->bundle;
 579         switch (p->ainsn.slot) {
 580                 case 0:
 581                         dest->quad0.slot0 = src->quad0.slot0;
 582                         break;
 583                 case 1:
 584                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 585                         break;
 586                 case 2:
 587                         dest->quad1.slot2 = src->quad1.slot2;
 588                         break;
 589         }
 590         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 591 }
 592
 593 void __kprobes arch_remove_kprobe(struct kprobe *p)
 594 {
 595         if (p->ainsn.insn) {
 596                 free_insn_slot(p->ainsn.insn,
 597                                p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
 598                 p->ainsn.insn = NULL;
 599         }
 600 }
 601 /*
 602  * We are resuming execution after a single step fault, so the pt_regs
 603  * structure reflects the register state after we executed the instruction
 604  * located in the kprobe (p->ainsn.insn->bundle).  We still need to adjust
 605  * the ip to point back to the original stack address. To set the IP address
 606  * to original stack address, handle the case where we need to fixup the
 607  * relative IP address and/or fixup branch register.
 608  */
 609 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 610 {
 611         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
 612         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
 613         unsigned long template;
 614         int slot = ((unsigned long)p->addr & 0xf);
 615
 616         template = p->ainsn.insn->bundle.quad0.template;
 617
 618         if (slot == 1 && bundle_encoding[template][1] == L)
 619                 slot = 2;
 620
 621         if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
 622
 623                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
 624                         /* Fix relative IP address */
 625                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
 626                                         resume_addr;
 627                 }
 628
 629                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
 630                 /*
 631                  * Fix target branch register, software convention is
 632                  * to use either b0 or b6 or b7, so just checking
 633                  * only those registers
 634                  */
 635                         switch (p->ainsn.target_br_reg) {
 636                         case 0:
 637                                 if ((regs->b0 == bundle_addr) ||
 638                                         (regs->b0 == bundle_addr + 0x10)) {
 639                                         regs->b0 = (regs->b0 - bundle_addr) +
 640                                                 resume_addr;
 641                                 }
 642                                 break;
 643                         case 6:
 644                                 if ((regs->b6 == bundle_addr) ||
 645                                         (regs->b6 == bundle_addr + 0x10)) {
 646                                         regs->b6 = (regs->b6 - bundle_addr) +
 647                                                 resume_addr;
 648                                 }
 649                                 break;
 650                         case 7:
 651                                 if ((regs->b7 == bundle_addr) ||
 652                                         (regs->b7 == bundle_addr + 0x10)) {
 653                                         regs->b7 = (regs->b7 - bundle_addr) +
 654                                                 resume_addr;
 655                                 }
 656                                 break;
 657                         } /* end switch */
 658                 }
 659                 goto turn_ss_off;
 660         }
 661
 662         if (slot == 2) {
 663                 if (regs->cr_iip == bundle_addr + 0x10) {
 664                         regs->cr_iip = resume_addr + 0x10;
 665                 }
 666         } else {
 667                 if (regs->cr_iip == bundle_addr) {
 668                         regs->cr_iip = resume_addr;
 669                 }
 670         }
 671
 672 turn_ss_off:
 673         /* Turn off Single Step bit */
 674         ia64_psr(regs)->ss = 0;
 675 }
 676
 677 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
 678 {
 679         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
 680         unsigned long slot = (unsigned long)p->addr & 0xf;
 681
 682         /* single step inline if break instruction */
 683         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
 684                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
 685         else
 686                 regs->cr_iip = bundle_addr & ~0xFULL;
 687
 688         if (slot > 2)
 689                 slot = 0;
 690
 691         ia64_psr(regs)->ri = slot;
 692
 693         /* turn on single stepping */
 694         ia64_psr(regs)->ss = 1;
 695 }
 696
 697 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
 698 {
 699         unsigned int slot = ia64_psr(regs)->ri;
 700         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
 701         bundle_t bundle;
 702
 703         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
 704
 705         return __is_ia64_break_inst(&bundle, slot);
 706 }
 707
 708 static int __kprobes pre_kprobes_handler(struct die_args *args)
 709 {
 710         struct kprobe *p;
 711         int ret = 0;
 712         struct pt_regs *regs = args->regs;
 713         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 714         struct kprobe_ctlblk *kcb;
 715
 716         /*
 717          * We don't want to be preempted for the entire
 718          * duration of kprobe processing
 719          */
 720         preempt_disable();
 721         kcb = get_kprobe_ctlblk();
 722
 723         /* Handle recursion cases */
 724         if (kprobe_running()) {
 725                 p = get_kprobe(addr);
 726                 if (p) {
 727                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
 728                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
 729                                 ia64_psr(regs)->ss = 0;
 730                                 goto no_kprobe;
 731                         }
 732                         /* We have reentered the pre_kprobe_handler(), since
 733                          * another probe was hit while within the handler.
 734                          * We here save the original kprobes variables and
 735                          * just single step on the instruction of the new probe
 736                          * without calling any user handlers.
 737                          */
 738                         save_previous_kprobe(kcb);
 739                         set_current_kprobe(p, kcb);
 740                         kprobes_inc_nmissed_count(p);
 741                         prepare_ss(p, regs);
 742                         kcb->kprobe_status = KPROBE_REENTER;
 743                         return 1;
 744                 } else if (!is_ia64_break_inst(regs)) {
 745                         /* The breakpoint instruction was removed by
 746                          * another cpu right after we hit, no further
 747                          * handling of this interrupt is appropriate
 748                          */
 749                         ret = 1;
 750                         goto no_kprobe;
 751                 } else {
 752                         /* Not our break */
 753                         goto no_kprobe;
 754                 }
 755         }
 756
 757         p = get_kprobe(addr);
 758         if (!p) {
 759                 if (!is_ia64_break_inst(regs)) {
 760                         /*
 761                          * The breakpoint instruction was removed right
 762                          * after we hit it.  Another cpu has removed
 763                          * either a probepoint or a debugger breakpoint
 764                          * at this address.  In either case, no further
 765                          * handling of this interrupt is appropriate.
 766                          */
 767                         ret = 1;
 768
 769                 }
 770
 771                 /* Not one of our break, let kernel handle it */
 772                 goto no_kprobe;
 773         }
 774
 775         set_current_kprobe(p, kcb);
 776         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 777
 778         if (p->pre_handler && p->pre_handler(p, regs)) {
 779                 reset_current_kprobe();
 780                 preempt_enable_no_resched();
 781                 return 1;
 782         }
 783
 784 #if !defined(CONFIG_PREEMPT)
 785         if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
 786                 /* Boost up -- we can execute copied instructions directly */
 787                 ia64_psr(regs)->ri = p->ainsn.slot;
 788                 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
 789                 /* turn single stepping off */
 790                 ia64_psr(regs)->ss = 0;
 791
 792                 reset_current_kprobe();
 793                 preempt_enable_no_resched();
 794                 return 1;
 795         }
 796 #endif
 797         prepare_ss(p, regs);
 798         kcb->kprobe_status = KPROBE_HIT_SS;
 799         return 1;
 800
 801 no_kprobe:
 802         preempt_enable_no_resched();
 803         return ret;
 804 }
 805
 806 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
 807 {
 808         struct kprobe *cur = kprobe_running();
 809         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 810
 811         if (!cur)
 812                 return 0;
 813
 814         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
 815                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
 816                 cur->post_handler(cur, regs, 0);
 817         }
 818
 819         resume_execution(cur, regs);
 820
 821         /*Restore back the original saved kprobes variables and continue. */
 822         if (kcb->kprobe_status == KPROBE_REENTER) {
 823                 restore_previous_kprobe(kcb);
 824                 goto out;
 825         }
 826         reset_current_kprobe();
 827
 828 out:
 829         preempt_enable_no_resched();
 830         return 1;
 831 }
 832
 833 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 834 {
 835         struct kprobe *cur = kprobe_running();
 836         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 837
 838
 839         switch(kcb->kprobe_status) {
 840         case KPROBE_HIT_SS:
 841         case KPROBE_REENTER:
 842                 /*
 843                  * We are here because the instruction being single
 844                  * stepped caused a page fault. We reset the current
 845                  * kprobe and the instruction pointer points back to
 846                  * the probe address and allow the page fault handler
 847                  * to continue as a normal page fault.
 848                  */
 849                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
 850                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
 851                 if (kcb->kprobe_status == KPROBE_REENTER)
 852                         restore_previous_kprobe(kcb);
 853                 else
 854                         reset_current_kprobe();
 855                 preempt_enable_no_resched();
 856                 break;
 857         case KPROBE_HIT_ACTIVE:
 858         case KPROBE_HIT_SSDONE:
 859                 /*
 860                  * We increment the nmissed count for accounting,
 861                  * we can also use npre/npostfault count for accounting
 862                  * these specific fault cases.
 863                  */
 864                 kprobes_inc_nmissed_count(cur);
 865
 866                 /*
 867                  * We come here because instructions in the pre/post
 868                  * handler caused the page_fault, this could happen
 869                  * if handler tries to access user space by
 870                  * copy_from_user(), get_user() etc. Let the
 871                  * user-specified handler try to fix it first.
 872                  */
 873                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
 874                         return 1;
 875                 /*
 876                  * In case the user-specified fault handler returned
 877                  * zero, try to fix up.
 878                  */
 879                 if (ia64_done_with_exception(regs))
 880                         return 1;
 881
 882                 /*
 883                  * Let ia64_do_page_fault() fix it.
 884                  */
 885                 break;
 886         default:
 887                 break;
 888         }
 889
 890         return 0;
 891 }
 892
 893 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 894                                        unsigned long val, void *data)
 895 {
 896         struct die_args *args = (struct die_args *)data;
 897         int ret = NOTIFY_DONE;
 898
 899         if (args->regs && user_mode(args->regs))
 900                 return ret;
 901
 902         switch(val) {
 903         case DIE_BREAK:
 904                 /* err is break number from ia64_bad_break() */
 905                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
 906                         || args->err == 0)
 907                         if (pre_kprobes_handler(args))
 908                                 ret = NOTIFY_STOP;
 909                 break;
 910         case DIE_FAULT:
 911                 /* err is vector number from ia64_fault() */
 912                 if (args->err == 36)
 913                         if (post_kprobes_handler(args->regs))
 914                                 ret = NOTIFY_STOP;
 915                 break;
 916         default:
 917                 break;
 918         }
 919         return ret;
 920 }
 921
 922 struct param_bsp_cfm {
 923         unsigned long ip;
 924         unsigned long *bsp;
 925         unsigned long cfm;
 926 };
 927
 928 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
 929 {
 930         unsigned long ip;
 931         struct param_bsp_cfm *lp = arg;
 932
 933         do {
 934                 unw_get_ip(info, &ip);
 935                 if (ip == 0)
 936                         break;
 937                 if (ip == lp->ip) {
 938                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
 939                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
 940                         return;
 941                 }
 942         } while (unw_unwind(info) >= 0);
 943         lp->bsp = NULL;
 944         lp->cfm = 0;
 945         return;
 946 }
 947
 948 unsigned long arch_deref_entry_point(void *entry)
 949 {
 950         return ((struct fnptr *)entry)->ip;
 951 }
 952
 953 static struct kprobe trampoline_p = {
 954         .pre_handler = trampoline_probe_handler
 955 };
 956
 957 int __init arch_init_kprobes(void)
 958 {
 959         trampoline_p.addr =
 960                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
 961         return register_kprobe(&trampoline_p);
 962 }
 963
 964 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 965 {
 966         if (p->addr ==
 967                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
 968                 return 1;
 969
 970         return 0;
 971 }