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 <[email protected]> and Anil S Keshavamurthy
  23  *              <[email protected]> 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 /*
 413  * At this point the target function has been tricked into
 414  * returning into our trampoline.  Lookup the associated instance
 415  * and then:
 416  *    - call the handler function
 417  *    - cleanup by marking the instance as unused
 418  *    - long jump back to the original return address
 419  */
 420 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 421 {
 422         struct kretprobe_instance *ri = NULL;
 423         struct hlist_head *head, empty_rp;
 424         struct hlist_node *tmp;
 425         unsigned long flags, orig_ret_address = 0;
 426         unsigned long trampoline_address =
 427                 ((struct fnptr *)kretprobe_trampoline)->ip;
 428
 429         INIT_HLIST_HEAD(&empty_rp);
 430         kretprobe_hash_lock(current, &head, &flags);
 431
 432         /*
 433          * It is possible to have multiple instances associated with a given
 434          * task either because an multiple functions in the call path
 435          * have a return probe installed on them, and/or more than one return
 436          * return probe was registered for a target function.
 437          *
 438          * We can handle this because:
 439          *     - instances are always inserted at the head of the list
 440          *     - when multiple return probes are registered for the same
 441          *       function, the first instance's ret_addr will point to the
 442          *       real return address, and all the rest will point to
 443          *       kretprobe_trampoline
 444          */
 445         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 446                 if (ri->task != current)
 447                         /* another task is sharing our hash bucket */
 448                         continue;
 449
 450                 orig_ret_address = (unsigned long)ri->ret_addr;
 451                 if (orig_ret_address != trampoline_address)
 452                         /*
 453                          * This is the real return address. Any other
 454                          * instances associated with this task are for
 455                          * other calls deeper on the call stack
 456                          */
 457                         break;
 458         }
 459
 460         regs->cr_iip = orig_ret_address;
 461
 462         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 463                 if (ri->task != current)
 464                         /* another task is sharing our hash bucket */
 465                         continue;
 466
 467                 if (ri->rp && ri->rp->handler)
 468                         ri->rp->handler(ri, regs);
 469
 470                 orig_ret_address = (unsigned long)ri->ret_addr;
 471                 recycle_rp_inst(ri, &empty_rp);
 472
 473                 if (orig_ret_address != trampoline_address)
 474                         /*
 475                          * This is the real return address. Any other
 476                          * instances associated with this task are for
 477                          * other calls deeper on the call stack
 478                          */
 479                         break;
 480         }
 481         kretprobe_assert(ri, orig_ret_address, trampoline_address);
 482
 483         kretprobe_hash_unlock(current, &flags);
 484
 485         hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
 486                 hlist_del(&ri->hlist);
 487                 kfree(ri);
 488         }
 489         /*
 490          * By returning a non-zero value, we are telling
 491          * kprobe_handler() that we don't want the post_handler
 492          * to run (and have re-enabled preemption)
 493          */
 494         return 1;
 495 }
 496
 497 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 498                                       struct pt_regs *regs)
 499 {
 500         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
 501
 502         /* Replace the return addr with trampoline addr */
 503         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
 504 }
 505
 506 /* Check the instruction in the slot is break */
 507 static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
 508 {
 509         unsigned int major_opcode;
 510         unsigned int template = bundle->quad0.template;
 511         unsigned long kprobe_inst;
 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 probe instruction at given slot*/
 518         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 519
 520         /* For break instruction,
 521          * Bits 37:40 Major opcode to be zero
 522          * Bits 27:32 X6 to be zero
 523          * Bits 32:35 X3 to be zero
 524          */
 525         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
 526                 /* Not a break instruction */
 527                 return 0;
 528         }
 529
 530         /* Is a break instruction */
 531         return 1;
 532 }
 533
 534 /*
 535  * In this function, we check whether the target bundle modifies IP or
 536  * it triggers an exception. If so, it cannot be boostable.
 537  */
 538 static int __kprobes can_boost(bundle_t *bundle, uint slot,
 539                                unsigned long bundle_addr)
 540 {
 541         unsigned int template = bundle->quad0.template;
 542
 543         do {
 544                 if (search_exception_tables(bundle_addr + slot) ||
 545                     __is_ia64_break_inst(bundle, slot))
 546                         return 0;       /* exception may occur in this bundle*/
 547         } while ((++slot) < 3);
 548         template &= 0x1e;
 549         if (template >= 0x10 /* including B unit */ ||
 550             template == 0x04 /* including X unit */ ||
 551             template == 0x06) /* undefined */
 552                 return 0;
 553
 554         return 1;
 555 }
 556
 557 /* Prepare long jump bundle and disables other boosters if need */
 558 static void __kprobes prepare_booster(struct kprobe *p)
 559 {
 560         unsigned long addr = (unsigned long)p->addr & ~0xFULL;
 561         unsigned int slot = (unsigned long)p->addr & 0xf;
 562         struct kprobe *other_kp;
 563
 564         if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
 565                 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
 566                 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
 567         }
 568
 569         /* disables boosters in previous slots */
 570         for (; addr < (unsigned long)p->addr; addr++) {
 571                 other_kp = get_kprobe((void *)addr);
 572                 if (other_kp)
 573                         other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
 574         }
 575 }
 576
 577 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 578 {
 579         unsigned long addr = (unsigned long) p->addr;
 580         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
 581         unsigned long kprobe_inst=0;
 582         unsigned int slot = addr & 0xf, template, major_opcode = 0;
 583         bundle_t *bundle;
 584         int qp;
 585
 586         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
 587         template = bundle->quad0.template;
 588
 589         if(valid_kprobe_addr(template, slot, addr))
 590                 return -EINVAL;
 591
 592         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 593         if (slot == 1 && bundle_encoding[template][1] == L)
 594                 slot++;
 595
 596         /* Get kprobe_inst and major_opcode from the bundle */
 597         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 598
 599         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
 600         if (qp < 0)
 601                 return -EINVAL;
 602
 603         p->ainsn.insn = get_insn_slot();
 604         if (!p->ainsn.insn)
 605                 return -ENOMEM;
 606         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
 607         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
 608
 609         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
 610
 611         prepare_booster(p);
 612
 613         return 0;
 614 }
 615
 616 void __kprobes arch_arm_kprobe(struct kprobe *p)
 617 {
 618         unsigned long arm_addr;
 619         bundle_t *src, *dest;
 620
 621         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 622         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 623         src = &p->opcode.bundle;
 624
 625         flush_icache_range((unsigned long)p->ainsn.insn,
 626                            (unsigned long)p->ainsn.insn +
 627                            sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
 628
 629         switch (p->ainsn.slot) {
 630                 case 0:
 631                         dest->quad0.slot0 = src->quad0.slot0;
 632                         break;
 633                 case 1:
 634                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 635                         break;
 636                 case 2:
 637                         dest->quad1.slot2 = src->quad1.slot2;
 638                         break;
 639         }
 640         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 641 }
 642
 643 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 644 {
 645         unsigned long arm_addr;
 646         bundle_t *src, *dest;
 647
 648         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 649         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 650         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
 651         src = &p->ainsn.insn->bundle;
 652         switch (p->ainsn.slot) {
 653                 case 0:
 654                         dest->quad0.slot0 = src->quad0.slot0;
 655                         break;
 656                 case 1:
 657                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 658                         break;
 659                 case 2:
 660                         dest->quad1.slot2 = src->quad1.slot2;
 661                         break;
 662         }
 663         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 664 }
 665
 666 void __kprobes arch_remove_kprobe(struct kprobe *p)
 667 {
 668         if (p->ainsn.insn) {
 669                 free_insn_slot(p->ainsn.insn,
 670                                p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
 671                 p->ainsn.insn = NULL;
 672         }
 673 }
 674 /*
 675  * We are resuming execution after a single step fault, so the pt_regs
 676  * structure reflects the register state after we executed the instruction
 677  * located in the kprobe (p->ainsn.insn->bundle).  We still need to adjust
 678  * the ip to point back to the original stack address. To set the IP address
 679  * to original stack address, handle the case where we need to fixup the
 680  * relative IP address and/or fixup branch register.
 681  */
 682 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 683 {
 684         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
 685         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
 686         unsigned long template;
 687         int slot = ((unsigned long)p->addr & 0xf);
 688
 689         template = p->ainsn.insn->bundle.quad0.template;
 690
 691         if (slot == 1 && bundle_encoding[template][1] == L)
 692                 slot = 2;
 693
 694         if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
 695
 696                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
 697                         /* Fix relative IP address */
 698                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
 699                                         resume_addr;
 700                 }
 701
 702                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
 703                 /*
 704                  * Fix target branch register, software convention is
 705                  * to use either b0 or b6 or b7, so just checking
 706                  * only those registers
 707                  */
 708                         switch (p->ainsn.target_br_reg) {
 709                         case 0:
 710                                 if ((regs->b0 == bundle_addr) ||
 711                                         (regs->b0 == bundle_addr + 0x10)) {
 712                                         regs->b0 = (regs->b0 - bundle_addr) +
 713                                                 resume_addr;
 714                                 }
 715                                 break;
 716                         case 6:
 717                                 if ((regs->b6 == bundle_addr) ||
 718                                         (regs->b6 == bundle_addr + 0x10)) {
 719                                         regs->b6 = (regs->b6 - bundle_addr) +
 720                                                 resume_addr;
 721                                 }
 722                                 break;
 723                         case 7:
 724                                 if ((regs->b7 == bundle_addr) ||
 725                                         (regs->b7 == bundle_addr + 0x10)) {
 726                                         regs->b7 = (regs->b7 - bundle_addr) +
 727                                                 resume_addr;
 728                                 }
 729                                 break;
 730                         } /* end switch */
 731                 }
 732                 goto turn_ss_off;
 733         }
 734
 735         if (slot == 2) {
 736                 if (regs->cr_iip == bundle_addr + 0x10) {
 737                         regs->cr_iip = resume_addr + 0x10;
 738                 }
 739         } else {
 740                 if (regs->cr_iip == bundle_addr) {
 741                         regs->cr_iip = resume_addr;
 742                 }
 743         }
 744
 745 turn_ss_off:
 746         /* Turn off Single Step bit */
 747         ia64_psr(regs)->ss = 0;
 748 }
 749
 750 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
 751 {
 752         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
 753         unsigned long slot = (unsigned long)p->addr & 0xf;
 754
 755         /* single step inline if break instruction */
 756         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
 757                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
 758         else
 759                 regs->cr_iip = bundle_addr & ~0xFULL;
 760
 761         if (slot > 2)
 762                 slot = 0;
 763
 764         ia64_psr(regs)->ri = slot;
 765
 766         /* turn on single stepping */
 767         ia64_psr(regs)->ss = 1;
 768 }
 769
 770 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
 771 {
 772         unsigned int slot = ia64_psr(regs)->ri;
 773         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
 774         bundle_t bundle;
 775
 776         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
 777
 778         return __is_ia64_break_inst(&bundle, slot);
 779 }
 780
 781 static int __kprobes pre_kprobes_handler(struct die_args *args)
 782 {
 783         struct kprobe *p;
 784         int ret = 0;
 785         struct pt_regs *regs = args->regs;
 786         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 787         struct kprobe_ctlblk *kcb;
 788
 789         /*
 790          * We don't want to be preempted for the entire
 791          * duration of kprobe processing
 792          */
 793         preempt_disable();
 794         kcb = get_kprobe_ctlblk();
 795
 796         /* Handle recursion cases */
 797         if (kprobe_running()) {
 798                 p = get_kprobe(addr);
 799                 if (p) {
 800                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
 801                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
 802                                 ia64_psr(regs)->ss = 0;
 803                                 goto no_kprobe;
 804                         }
 805                         /* We have reentered the pre_kprobe_handler(), since
 806                          * another probe was hit while within the handler.
 807                          * We here save the original kprobes variables and
 808                          * just single step on the instruction of the new probe
 809                          * without calling any user handlers.
 810                          */
 811                         save_previous_kprobe(kcb);
 812                         set_current_kprobe(p, kcb);
 813                         kprobes_inc_nmissed_count(p);
 814                         prepare_ss(p, regs);
 815                         kcb->kprobe_status = KPROBE_REENTER;
 816                         return 1;
 817                 } else if (!is_ia64_break_inst(regs)) {
 818                         /* The breakpoint instruction was removed by
 819                          * another cpu right after we hit, no further
 820                          * handling of this interrupt is appropriate
 821                          */
 822                         ret = 1;
 823                         goto no_kprobe;
 824                 } else {
 825                         /* Not our break */
 826                         goto no_kprobe;
 827                 }
 828         }
 829
 830         p = get_kprobe(addr);
 831         if (!p) {
 832                 if (!is_ia64_break_inst(regs)) {
 833                         /*
 834                          * The breakpoint instruction was removed right
 835                          * after we hit it.  Another cpu has removed
 836                          * either a probepoint or a debugger breakpoint
 837                          * at this address.  In either case, no further
 838                          * handling of this interrupt is appropriate.
 839                          */
 840                         ret = 1;
 841
 842                 }
 843
 844                 /* Not one of our break, let kernel handle it */
 845                 goto no_kprobe;
 846         }
 847
 848         set_current_kprobe(p, kcb);
 849         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 850
 851         if (p->pre_handler && p->pre_handler(p, regs)) {
 852                 reset_current_kprobe();
 853                 preempt_enable_no_resched();
 854                 return 1;
 855         }
 856
 857 #if !defined(CONFIG_PREEMPT)
 858         if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
 859                 /* Boost up -- we can execute copied instructions directly */
 860                 ia64_psr(regs)->ri = p->ainsn.slot;
 861                 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
 862                 /* turn single stepping off */
 863                 ia64_psr(regs)->ss = 0;
 864
 865                 reset_current_kprobe();
 866                 preempt_enable_no_resched();
 867                 return 1;
 868         }
 869 #endif
 870         prepare_ss(p, regs);
 871         kcb->kprobe_status = KPROBE_HIT_SS;
 872         return 1;
 873
 874 no_kprobe:
 875         preempt_enable_no_resched();
 876         return ret;
 877 }
 878
 879 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
 880 {
 881         struct kprobe *cur = kprobe_running();
 882         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 883
 884         if (!cur)
 885                 return 0;
 886
 887         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
 888                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
 889                 cur->post_handler(cur, regs, 0);
 890         }
 891
 892         resume_execution(cur, regs);
 893
 894         /*Restore back the original saved kprobes variables and continue. */
 895         if (kcb->kprobe_status == KPROBE_REENTER) {
 896                 restore_previous_kprobe(kcb);
 897                 goto out;
 898         }
 899         reset_current_kprobe();
 900
 901 out:
 902         preempt_enable_no_resched();
 903         return 1;
 904 }
 905
 906 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 907 {
 908         struct kprobe *cur = kprobe_running();
 909         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 910
 911
 912         switch(kcb->kprobe_status) {
 913         case KPROBE_HIT_SS:
 914         case KPROBE_REENTER:
 915                 /*
 916                  * We are here because the instruction being single
 917                  * stepped caused a page fault. We reset the current
 918                  * kprobe and the instruction pointer points back to
 919                  * the probe address and allow the page fault handler
 920                  * to continue as a normal page fault.
 921                  */
 922                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
 923                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
 924                 if (kcb->kprobe_status == KPROBE_REENTER)
 925                         restore_previous_kprobe(kcb);
 926                 else
 927                         reset_current_kprobe();
 928                 preempt_enable_no_resched();
 929                 break;
 930         case KPROBE_HIT_ACTIVE:
 931         case KPROBE_HIT_SSDONE:
 932                 /*
 933                  * We increment the nmissed count for accounting,
 934                  * we can also use npre/npostfault count for accounting
 935                  * these specific fault cases.
 936                  */
 937                 kprobes_inc_nmissed_count(cur);
 938
 939                 /*
 940                  * We come here because instructions in the pre/post
 941                  * handler caused the page_fault, this could happen
 942                  * if handler tries to access user space by
 943                  * copy_from_user(), get_user() etc. Let the
 944                  * user-specified handler try to fix it first.
 945                  */
 946                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
 947                         return 1;
 948                 /*
 949                  * In case the user-specified fault handler returned
 950                  * zero, try to fix up.
 951                  */
 952                 if (ia64_done_with_exception(regs))
 953                         return 1;
 954
 955                 /*
 956                  * Let ia64_do_page_fault() fix it.
 957                  */
 958                 break;
 959         default:
 960                 break;
 961         }
 962
 963         return 0;
 964 }
 965
 966 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 967                                        unsigned long val, void *data)
 968 {
 969         struct die_args *args = (struct die_args *)data;
 970         int ret = NOTIFY_DONE;
 971
 972         if (args->regs && user_mode(args->regs))
 973                 return ret;
 974
 975         switch(val) {
 976         case DIE_BREAK:
 977                 /* err is break number from ia64_bad_break() */
 978                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
 979                         || args->err == 0)
 980                         if (pre_kprobes_handler(args))
 981                                 ret = NOTIFY_STOP;
 982                 break;
 983         case DIE_FAULT:
 984                 /* err is vector number from ia64_fault() */
 985                 if (args->err == 36)
 986                         if (post_kprobes_handler(args->regs))
 987                                 ret = NOTIFY_STOP;
 988                 break;
 989         default:
 990                 break;
 991         }
 992         return ret;
 993 }
 994
 995 struct param_bsp_cfm {
 996         unsigned long ip;
 997         unsigned long *bsp;
 998         unsigned long cfm;
 999 };
1000
1001 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
1002 {
1003         unsigned long ip;
1004         struct param_bsp_cfm *lp = arg;
1005
1006         do {
1007                 unw_get_ip(info, &ip);
1008                 if (ip == 0)
1009                         break;
1010                 if (ip == lp->ip) {
1011                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
1012                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
1013                         return;
1014                 }
1015         } while (unw_unwind(info) >= 0);
1016         lp->bsp = NULL;
1017         lp->cfm = 0;
1018         return;
1019 }
1020
1021 unsigned long arch_deref_entry_point(void *entry)
1022 {
1023         return ((struct fnptr *)entry)->ip;
1024 }
1025
1026 static struct kprobe trampoline_p = {
1027         .pre_handler = trampoline_probe_handler
1028 };
1029
1030 int __init arch_init_kprobes(void)
1031 {
1032         trampoline_p.addr =
1033                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1034         return register_kprobe(&trampoline_p);
1035 }
1036
1037 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1038 {
1039         if (p->addr ==
1040                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1041                 return 1;
1042
1043         return 0;
1044 }