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 /* Insert a long branch code */
  82 static void __kprobes set_brl_inst(void *from, void *to)
  83 {
  84         s64 rel = ((s64) to - (s64) from) >> 4;
  85         bundle_t *brl;
  86         brl = (bundle_t *) ((u64) from & ~0xf);
  87         brl->quad0.template = 0x05;     /* [MLX](stop) */
  88         brl->quad0.slot0 = NOP_M_INST;  /* nop.m 0x0 */
  89         brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
  90         brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
  91         /* brl.cond.sptk.many.clr rel<<4 (qp=0) */
  92         brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
  93 }
  94
  95 /*
  96  * In this function we check to see if the instruction
  97  * is IP relative instruction and update the kprobe
  98  * inst flag accordingly
  99  */
 100 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
 101                                               uint major_opcode,
 102                                               unsigned long kprobe_inst,
 103                                               struct kprobe *p)
 104 {
 105         p->ainsn.inst_flag = 0;
 106         p->ainsn.target_br_reg = 0;
 107         p->ainsn.slot = slot;
 108
 109         /* Check for Break instruction
 110          * Bits 37:40 Major opcode to be zero
 111          * Bits 27:32 X6 to be zero
 112          * Bits 32:35 X3 to be zero
 113          */
 114         if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
 115                 /* is a break instruction */
 116                 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
 117                 return;
 118         }
 119
 120         if (bundle_encoding[template][slot] == B) {
 121                 switch (major_opcode) {
 122                   case INDIRECT_CALL_OPCODE:
 123                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 124                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 125                         break;
 126                   case IP_RELATIVE_PREDICT_OPCODE:
 127                   case IP_RELATIVE_BRANCH_OPCODE:
 128                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 129                         break;
 130                   case IP_RELATIVE_CALL_OPCODE:
 131                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 132                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 133                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 134                         break;
 135                 }
 136         } else if (bundle_encoding[template][slot] == X) {
 137                 switch (major_opcode) {
 138                   case LONG_CALL_OPCODE:
 139                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 140                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 141                   break;
 142                 }
 143         }
 144         return;
 145 }
 146
 147 /*
 148  * In this function we check to see if the instruction
 149  * (qp) cmpx.crel.ctype p1,p2=r2,r3
 150  * on which we are inserting kprobe is cmp instruction
 151  * with ctype as unc.
 152  */
 153 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
 154                                             uint major_opcode,
 155                                             unsigned long kprobe_inst)
 156 {
 157         cmp_inst_t cmp_inst;
 158         uint ctype_unc = 0;
 159
 160         if (!((bundle_encoding[template][slot] == I) ||
 161                 (bundle_encoding[template][slot] == M)))
 162                 goto out;
 163
 164         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
 165                 (major_opcode == 0xE)))
 166                 goto out;
 167
 168         cmp_inst.l = kprobe_inst;
 169         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
 170                 /* Integer compare - Register Register (A6 type)*/
 171                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
 172                                 &&(cmp_inst.f.c == 1))
 173                         ctype_unc = 1;
 174         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
 175                 /* Integer compare - Immediate Register (A8 type)*/
 176                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
 177                         ctype_unc = 1;
 178         }
 179 out:
 180         return ctype_unc;
 181 }
 182
 183 /*
 184  * In this function we check to see if the instruction
 185  * on which we are inserting kprobe is supported.
 186  * Returns qp value if supported
 187  * Returns -EINVAL if unsupported
 188  */
 189 static int __kprobes unsupported_inst(uint template, uint  slot,
 190                                       uint major_opcode,
 191                                       unsigned long kprobe_inst,
 192                                       unsigned long addr)
 193 {
 194         int qp;
 195
 196         qp = kprobe_inst & 0x3f;
 197         if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
 198                 if (slot == 1 && qp)  {
 199                         printk(KERN_WARNING "Kprobes on cmp unc "
 200                                         "instruction on slot 1 at <0x%lx> "
 201                                         "is not supported\n", addr);
 202                         return -EINVAL;
 203
 204                 }
 205                 qp = 0;
 206         }
 207         else if (bundle_encoding[template][slot] == I) {
 208                 if (major_opcode == 0) {
 209                         /*
 210                          * Check for Integer speculation instruction
 211                          * - Bit 33-35 to be equal to 0x1
 212                          */
 213                         if (((kprobe_inst >> 33) & 0x7) == 1) {
 214                                 printk(KERN_WARNING
 215                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
 216                                                 addr);
 217                                 return -EINVAL;
 218                         }
 219                         /*
 220                          * IP relative mov instruction
 221                          *  - Bit 27-35 to be equal to 0x30
 222                          */
 223                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
 224                                 printk(KERN_WARNING
 225                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
 226                                                 addr);
 227                                 return -EINVAL;
 228
 229                         }
 230                 }
 231                 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
 232                                 (kprobe_inst & (0x1UL << 12))) {
 233                         /* test bit instructions, tbit,tnat,tf
 234                          * bit 33-36 to be equal to 0
 235                          * bit 12 to be equal to 1
 236                          */
 237                         if (slot == 1 && qp) {
 238                                 printk(KERN_WARNING "Kprobes on test bit "
 239                                                 "instruction on slot at <0x%lx> "
 240                                                 "is not supported\n", addr);
 241                                 return -EINVAL;
 242                         }
 243                         qp = 0;
 244                 }
 245         }
 246         else if (bundle_encoding[template][slot] == B) {
 247                 if (major_opcode == 7) {
 248                         /* IP-Relative Predict major code is 7 */
 249                         printk(KERN_WARNING "Kprobes on IP-Relative"
 250                                         "Predict is not supported\n");
 251                         return -EINVAL;
 252                 }
 253                 else if (major_opcode == 2) {
 254                         /* Indirect Predict, major code is 2
 255                          * bit 27-32 to be equal to 10 or 11
 256                          */
 257                         int x6=(kprobe_inst >> 27) & 0x3F;
 258                         if ((x6 == 0x10) || (x6 == 0x11)) {
 259                                 printk(KERN_WARNING "Kprobes on "
 260                                         "Indirect Predict is not supported\n");
 261                                 return -EINVAL;
 262                         }
 263                 }
 264         }
 265         /* kernel does not use float instruction, here for safety kprobe
 266          * will judge whether it is fcmp/flass/float approximation instruction
 267          */
 268         else if (unlikely(bundle_encoding[template][slot] == F)) {
 269                 if ((major_opcode == 4 || major_opcode == 5) &&
 270                                 (kprobe_inst  & (0x1 << 12))) {
 271                         /* fcmp/fclass unc instruction */
 272                         if (slot == 1 && qp) {
 273                                 printk(KERN_WARNING "Kprobes on fcmp/fclass "
 274                                         "instruction on slot at <0x%lx> "
 275                                         "is not supported\n", addr);
 276                                 return -EINVAL;
 277
 278                         }
 279                         qp = 0;
 280                 }
 281                 if ((major_opcode == 0 || major_opcode == 1) &&
 282                         (kprobe_inst & (0x1UL << 33))) {
 283                         /* float Approximation instruction */
 284                         if (slot == 1 && qp) {
 285                                 printk(KERN_WARNING "Kprobes on float Approx "
 286                                         "instr at <0x%lx> is not supported\n",
 287                                                 addr);
 288                                 return -EINVAL;
 289                         }
 290                         qp = 0;
 291                 }
 292         }
 293         return qp;
 294 }
 295
 296 /*
 297  * In this function we override the bundle with
 298  * the break instruction at the given slot.
 299  */
 300 static void __kprobes prepare_break_inst(uint template, uint  slot,
 301                                          uint major_opcode,
 302                                          unsigned long kprobe_inst,
 303                                          struct kprobe *p,
 304                                          int qp)
 305 {
 306         unsigned long break_inst = BREAK_INST;
 307         bundle_t *bundle = &p->opcode.bundle;
 308
 309         /*
 310          * Copy the original kprobe_inst qualifying predicate(qp)
 311          * to the break instruction
 312          */
 313         break_inst |= qp;
 314
 315         switch (slot) {
 316           case 0:
 317                 bundle->quad0.slot0 = break_inst;
 318                 break;
 319           case 1:
 320                 bundle->quad0.slot1_p0 = break_inst;
 321                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
 322                 break;
 323           case 2:
 324                 bundle->quad1.slot2 = break_inst;
 325                 break;
 326         }
 327
 328         /*
 329          * Update the instruction flag, so that we can
 330          * emulate the instruction properly after we
 331          * single step on original instruction
 332          */
 333         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
 334 }
 335
 336 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
 337                 unsigned long *kprobe_inst, uint *major_opcode)
 338 {
 339         unsigned long kprobe_inst_p0, kprobe_inst_p1;
 340         unsigned int template;
 341
 342         template = bundle->quad0.template;
 343
 344         switch (slot) {
 345           case 0:
 346                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
 347                 *kprobe_inst = bundle->quad0.slot0;
 348                   break;
 349           case 1:
 350                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
 351                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
 352                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
 353                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
 354                 break;
 355           case 2:
 356                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
 357                 *kprobe_inst = bundle->quad1.slot2;
 358                 break;
 359         }
 360 }
 361
 362 /* Returns non-zero if the addr is in the Interrupt Vector Table */
 363 static int __kprobes in_ivt_functions(unsigned long addr)
 364 {
 365         return (addr >= (unsigned long)__start_ivt_text
 366                 && addr < (unsigned long)__end_ivt_text);
 367 }
 368
 369 static int __kprobes valid_kprobe_addr(int template, int slot,
 370                                        unsigned long addr)
 371 {
 372         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
 373                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
 374                                 "at 0x%lx\n", addr);
 375                 return -EINVAL;
 376         }
 377
 378         if (in_ivt_functions(addr)) {
 379                 printk(KERN_WARNING "Kprobes can't be inserted inside "
 380                                 "IVT functions at 0x%lx\n", addr);
 381                 return -EINVAL;
 382         }
 383
 384         return 0;
 385 }
 386
 387 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
 388 {
 389         unsigned int i;
 390         i = atomic_add_return(1, &kcb->prev_kprobe_index);
 391         kcb->prev_kprobe[i-1].kp = kprobe_running();
 392         kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
 393 }
 394
 395 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 396 {
 397         unsigned int i;
 398         i = atomic_read(&kcb->prev_kprobe_index);
 399         __this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp);
 400         kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
 401         atomic_sub(1, &kcb->prev_kprobe_index);
 402 }
 403
 404 static void __kprobes set_current_kprobe(struct kprobe *p,
 405                         struct kprobe_ctlblk *kcb)
 406 {
 407         __this_cpu_write(current_kprobe, p);
 408 }
 409
 410 static void kretprobe_trampoline(void)
 411 {
 412 }
 413
 414 /*
 415  * At this point the target function has been tricked into
 416  * returning into our trampoline.  Lookup the associated instance
 417  * and then:
 418  *    - call the handler function
 419  *    - cleanup by marking the instance as unused
 420  *    - long jump back to the original return address
 421  */
 422 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 423 {
 424         struct kretprobe_instance *ri = NULL;
 425         struct hlist_head *head, empty_rp;
 426         struct hlist_node *tmp;
 427         unsigned long flags, orig_ret_address = 0;
 428         unsigned long trampoline_address =
 429                 ((struct fnptr *)kretprobe_trampoline)->ip;
 430
 431         INIT_HLIST_HEAD(&empty_rp);
 432         kretprobe_hash_lock(current, &head, &flags);
 433
 434         /*
 435          * It is possible to have multiple instances associated with a given
 436          * task either because an multiple functions in the call path
 437          * have a return probe installed on them, and/or more than one return
 438          * return probe was registered for a target function.
 439          *
 440          * We can handle this because:
 441          *     - instances are always inserted at the head of the list
 442          *     - when multiple return probes are registered for the same
 443          *       function, the first instance's ret_addr will point to the
 444          *       real return address, and all the rest will point to
 445          *       kretprobe_trampoline
 446          */
 447         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 448                 if (ri->task != current)
 449                         /* another task is sharing our hash bucket */
 450                         continue;
 451
 452                 orig_ret_address = (unsigned long)ri->ret_addr;
 453                 if (orig_ret_address != trampoline_address)
 454                         /*
 455                          * This is the real return address. Any other
 456                          * instances associated with this task are for
 457                          * other calls deeper on the call stack
 458                          */
 459                         break;
 460         }
 461
 462         regs->cr_iip = orig_ret_address;
 463
 464         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 465                 if (ri->task != current)
 466                         /* another task is sharing our hash bucket */
 467                         continue;
 468
 469                 if (ri->rp && ri->rp->handler)
 470                         ri->rp->handler(ri, regs);
 471
 472                 orig_ret_address = (unsigned long)ri->ret_addr;
 473                 recycle_rp_inst(ri, &empty_rp);
 474
 475                 if (orig_ret_address != trampoline_address)
 476                         /*
 477                          * This is the real return address. Any other
 478                          * instances associated with this task are for
 479                          * other calls deeper on the call stack
 480                          */
 481                         break;
 482         }
 483
 484         kretprobe_assert(ri, orig_ret_address, trampoline_address);
 485
 486         reset_current_kprobe();
 487         kretprobe_hash_unlock(current, &flags);
 488         preempt_enable_no_resched();
 489
 490         hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
 491                 hlist_del(&ri->hlist);
 492                 kfree(ri);
 493         }
 494         /*
 495          * By returning a non-zero value, we are telling
 496          * kprobe_handler() that we don't want the post_handler
 497          * to run (and have re-enabled preemption)
 498          */
 499         return 1;
 500 }
 501
 502 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 503                                       struct pt_regs *regs)
 504 {
 505         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
 506
 507         /* Replace the return addr with trampoline addr */
 508         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
 509 }
 510
 511 /* Check the instruction in the slot is break */
 512 static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
 513 {
 514         unsigned int major_opcode;
 515         unsigned int template = bundle->quad0.template;
 516         unsigned long kprobe_inst;
 517
 518         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 519         if (slot == 1 && bundle_encoding[template][1] == L)
 520                 slot++;
 521
 522         /* Get Kprobe probe instruction at given slot*/
 523         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 524
 525         /* For break instruction,
 526          * Bits 37:40 Major opcode to be zero
 527          * Bits 27:32 X6 to be zero
 528          * Bits 32:35 X3 to be zero
 529          */
 530         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
 531                 /* Not a break instruction */
 532                 return 0;
 533         }
 534
 535         /* Is a break instruction */
 536         return 1;
 537 }
 538
 539 /*
 540  * In this function, we check whether the target bundle modifies IP or
 541  * it triggers an exception. If so, it cannot be boostable.
 542  */
 543 static int __kprobes can_boost(bundle_t *bundle, uint slot,
 544                                unsigned long bundle_addr)
 545 {
 546         unsigned int template = bundle->quad0.template;
 547
 548         do {
 549                 if (search_exception_tables(bundle_addr + slot) ||
 550                     __is_ia64_break_inst(bundle, slot))
 551                         return 0;       /* exception may occur in this bundle*/
 552         } while ((++slot) < 3);
 553         template &= 0x1e;
 554         if (template >= 0x10 /* including B unit */ ||
 555             template == 0x04 /* including X unit */ ||
 556             template == 0x06) /* undefined */
 557                 return 0;
 558
 559         return 1;
 560 }
 561
 562 /* Prepare long jump bundle and disables other boosters if need */
 563 static void __kprobes prepare_booster(struct kprobe *p)
 564 {
 565         unsigned long addr = (unsigned long)p->addr & ~0xFULL;
 566         unsigned int slot = (unsigned long)p->addr & 0xf;
 567         struct kprobe *other_kp;
 568
 569         if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
 570                 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
 571                 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
 572         }
 573
 574         /* disables boosters in previous slots */
 575         for (; addr < (unsigned long)p->addr; addr++) {
 576                 other_kp = get_kprobe((void *)addr);
 577                 if (other_kp)
 578                         other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
 579         }
 580 }
 581
 582 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 583 {
 584         unsigned long addr = (unsigned long) p->addr;
 585         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
 586         unsigned long kprobe_inst=0;
 587         unsigned int slot = addr & 0xf, template, major_opcode = 0;
 588         bundle_t *bundle;
 589         int qp;
 590
 591         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
 592         template = bundle->quad0.template;
 593
 594         if(valid_kprobe_addr(template, slot, addr))
 595                 return -EINVAL;
 596
 597         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 598         if (slot == 1 && bundle_encoding[template][1] == L)
 599                 slot++;
 600
 601         /* Get kprobe_inst and major_opcode from the bundle */
 602         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 603
 604         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
 605         if (qp < 0)
 606                 return -EINVAL;
 607
 608         p->ainsn.insn = get_insn_slot();
 609         if (!p->ainsn.insn)
 610                 return -ENOMEM;
 611         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
 612         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
 613
 614         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
 615
 616         prepare_booster(p);
 617
 618         return 0;
 619 }
 620
 621 void __kprobes arch_arm_kprobe(struct kprobe *p)
 622 {
 623         unsigned long arm_addr;
 624         bundle_t *src, *dest;
 625
 626         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 627         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 628         src = &p->opcode.bundle;
 629
 630         flush_icache_range((unsigned long)p->ainsn.insn,
 631                            (unsigned long)p->ainsn.insn +
 632                            sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
 633
 634         switch (p->ainsn.slot) {
 635                 case 0:
 636                         dest->quad0.slot0 = src->quad0.slot0;
 637                         break;
 638                 case 1:
 639                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 640                         break;
 641                 case 2:
 642                         dest->quad1.slot2 = src->quad1.slot2;
 643                         break;
 644         }
 645         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 646 }
 647
 648 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 649 {
 650         unsigned long arm_addr;
 651         bundle_t *src, *dest;
 652
 653         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 654         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 655         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
 656         src = &p->ainsn.insn->bundle;
 657         switch (p->ainsn.slot) {
 658                 case 0:
 659                         dest->quad0.slot0 = src->quad0.slot0;
 660                         break;
 661                 case 1:
 662                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 663                         break;
 664                 case 2:
 665                         dest->quad1.slot2 = src->quad1.slot2;
 666                         break;
 667         }
 668         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 669 }
 670
 671 void __kprobes arch_remove_kprobe(struct kprobe *p)
 672 {
 673         if (p->ainsn.insn) {
 674                 free_insn_slot(p->ainsn.insn,
 675                                p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
 676                 p->ainsn.insn = NULL;
 677         }
 678 }
 679 /*
 680  * We are resuming execution after a single step fault, so the pt_regs
 681  * structure reflects the register state after we executed the instruction
 682  * located in the kprobe (p->ainsn.insn->bundle).  We still need to adjust
 683  * the ip to point back to the original stack address. To set the IP address
 684  * to original stack address, handle the case where we need to fixup the
 685  * relative IP address and/or fixup branch register.
 686  */
 687 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 688 {
 689         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
 690         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
 691         unsigned long template;
 692         int slot = ((unsigned long)p->addr & 0xf);
 693
 694         template = p->ainsn.insn->bundle.quad0.template;
 695
 696         if (slot == 1 && bundle_encoding[template][1] == L)
 697                 slot = 2;
 698
 699         if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
 700
 701                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
 702                         /* Fix relative IP address */
 703                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
 704                                         resume_addr;
 705                 }
 706
 707                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
 708                 /*
 709                  * Fix target branch register, software convention is
 710                  * to use either b0 or b6 or b7, so just checking
 711                  * only those registers
 712                  */
 713                         switch (p->ainsn.target_br_reg) {
 714                         case 0:
 715                                 if ((regs->b0 == bundle_addr) ||
 716                                         (regs->b0 == bundle_addr + 0x10)) {
 717                                         regs->b0 = (regs->b0 - bundle_addr) +
 718                                                 resume_addr;
 719                                 }
 720                                 break;
 721                         case 6:
 722                                 if ((regs->b6 == bundle_addr) ||
 723                                         (regs->b6 == bundle_addr + 0x10)) {
 724                                         regs->b6 = (regs->b6 - bundle_addr) +
 725                                                 resume_addr;
 726                                 }
 727                                 break;
 728                         case 7:
 729                                 if ((regs->b7 == bundle_addr) ||
 730                                         (regs->b7 == bundle_addr + 0x10)) {
 731                                         regs->b7 = (regs->b7 - bundle_addr) +
 732                                                 resume_addr;
 733                                 }
 734                                 break;
 735                         } /* end switch */
 736                 }
 737                 goto turn_ss_off;
 738         }
 739
 740         if (slot == 2) {
 741                 if (regs->cr_iip == bundle_addr + 0x10) {
 742                         regs->cr_iip = resume_addr + 0x10;
 743                 }
 744         } else {
 745                 if (regs->cr_iip == bundle_addr) {
 746                         regs->cr_iip = resume_addr;
 747                 }
 748         }
 749
 750 turn_ss_off:
 751         /* Turn off Single Step bit */
 752         ia64_psr(regs)->ss = 0;
 753 }
 754
 755 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
 756 {
 757         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
 758         unsigned long slot = (unsigned long)p->addr & 0xf;
 759
 760         /* single step inline if break instruction */
 761         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
 762                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
 763         else
 764                 regs->cr_iip = bundle_addr & ~0xFULL;
 765
 766         if (slot > 2)
 767                 slot = 0;
 768
 769         ia64_psr(regs)->ri = slot;
 770
 771         /* turn on single stepping */
 772         ia64_psr(regs)->ss = 1;
 773 }
 774
 775 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
 776 {
 777         unsigned int slot = ia64_psr(regs)->ri;
 778         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
 779         bundle_t bundle;
 780
 781         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
 782
 783         return __is_ia64_break_inst(&bundle, slot);
 784 }
 785
 786 static int __kprobes pre_kprobes_handler(struct die_args *args)
 787 {
 788         struct kprobe *p;
 789         int ret = 0;
 790         struct pt_regs *regs = args->regs;
 791         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 792         struct kprobe_ctlblk *kcb;
 793
 794         /*
 795          * We don't want to be preempted for the entire
 796          * duration of kprobe processing
 797          */
 798         preempt_disable();
 799         kcb = get_kprobe_ctlblk();
 800
 801         /* Handle recursion cases */
 802         if (kprobe_running()) {
 803                 p = get_kprobe(addr);
 804                 if (p) {
 805                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
 806                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
 807                                 ia64_psr(regs)->ss = 0;
 808                                 goto no_kprobe;
 809                         }
 810                         /* We have reentered the pre_kprobe_handler(), since
 811                          * another probe was hit while within the handler.
 812                          * We here save the original kprobes variables and
 813                          * just single step on the instruction of the new probe
 814                          * without calling any user handlers.
 815                          */
 816                         save_previous_kprobe(kcb);
 817                         set_current_kprobe(p, kcb);
 818                         kprobes_inc_nmissed_count(p);
 819                         prepare_ss(p, regs);
 820                         kcb->kprobe_status = KPROBE_REENTER;
 821                         return 1;
 822                 } else if (args->err == __IA64_BREAK_JPROBE) {
 823                         /*
 824                          * jprobe instrumented function just completed
 825                          */
 826                         p = __this_cpu_read(current_kprobe);
 827                         if (p->break_handler && p->break_handler(p, regs)) {
 828                                 goto ss_probe;
 829                         }
 830                 } else if (!is_ia64_break_inst(regs)) {
 831                         /* The breakpoint instruction was removed by
 832                          * another cpu right after we hit, no further
 833                          * handling of this interrupt is appropriate
 834                          */
 835                         ret = 1;
 836                         goto no_kprobe;
 837                 } else {
 838                         /* Not our break */
 839                         goto no_kprobe;
 840                 }
 841         }
 842
 843         p = get_kprobe(addr);
 844         if (!p) {
 845                 if (!is_ia64_break_inst(regs)) {
 846                         /*
 847                          * The breakpoint instruction was removed right
 848                          * after we hit it.  Another cpu has removed
 849                          * either a probepoint or a debugger breakpoint
 850                          * at this address.  In either case, no further
 851                          * handling of this interrupt is appropriate.
 852                          */
 853                         ret = 1;
 854
 855                 }
 856
 857                 /* Not one of our break, let kernel handle it */
 858                 goto no_kprobe;
 859         }
 860
 861         set_current_kprobe(p, kcb);
 862         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 863
 864         if (p->pre_handler && p->pre_handler(p, regs))
 865                 /*
 866                  * Our pre-handler is specifically requesting that we just
 867                  * do a return.  This is used for both the jprobe pre-handler
 868                  * and the kretprobe trampoline
 869                  */
 870                 return 1;
 871
 872 ss_probe:
 873 #if !defined(CONFIG_PREEMPT)
 874         if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
 875                 /* Boost up -- we can execute copied instructions directly */
 876                 ia64_psr(regs)->ri = p->ainsn.slot;
 877                 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
 878                 /* turn single stepping off */
 879                 ia64_psr(regs)->ss = 0;
 880
 881                 reset_current_kprobe();
 882                 preempt_enable_no_resched();
 883                 return 1;
 884         }
 885 #endif
 886         prepare_ss(p, regs);
 887         kcb->kprobe_status = KPROBE_HIT_SS;
 888         return 1;
 889
 890 no_kprobe:
 891         preempt_enable_no_resched();
 892         return ret;
 893 }
 894
 895 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
 896 {
 897         struct kprobe *cur = kprobe_running();
 898         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 899
 900         if (!cur)
 901                 return 0;
 902
 903         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
 904                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
 905                 cur->post_handler(cur, regs, 0);
 906         }
 907
 908         resume_execution(cur, regs);
 909
 910         /*Restore back the original saved kprobes variables and continue. */
 911         if (kcb->kprobe_status == KPROBE_REENTER) {
 912                 restore_previous_kprobe(kcb);
 913                 goto out;
 914         }
 915         reset_current_kprobe();
 916
 917 out:
 918         preempt_enable_no_resched();
 919         return 1;
 920 }
 921
 922 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 923 {
 924         struct kprobe *cur = kprobe_running();
 925         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 926
 927
 928         switch(kcb->kprobe_status) {
 929         case KPROBE_HIT_SS:
 930         case KPROBE_REENTER:
 931                 /*
 932                  * We are here because the instruction being single
 933                  * stepped caused a page fault. We reset the current
 934                  * kprobe and the instruction pointer points back to
 935                  * the probe address and allow the page fault handler
 936                  * to continue as a normal page fault.
 937                  */
 938                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
 939                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
 940                 if (kcb->kprobe_status == KPROBE_REENTER)
 941                         restore_previous_kprobe(kcb);
 942                 else
 943                         reset_current_kprobe();
 944                 preempt_enable_no_resched();
 945                 break;
 946         case KPROBE_HIT_ACTIVE:
 947         case KPROBE_HIT_SSDONE:
 948                 /*
 949                  * We increment the nmissed count for accounting,
 950                  * we can also use npre/npostfault count for accounting
 951                  * these specific fault cases.
 952                  */
 953                 kprobes_inc_nmissed_count(cur);
 954
 955                 /*
 956                  * We come here because instructions in the pre/post
 957                  * handler caused the page_fault, this could happen
 958                  * if handler tries to access user space by
 959                  * copy_from_user(), get_user() etc. Let the
 960                  * user-specified handler try to fix it first.
 961                  */
 962                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
 963                         return 1;
 964                 /*
 965                  * In case the user-specified fault handler returned
 966                  * zero, try to fix up.
 967                  */
 968                 if (ia64_done_with_exception(regs))
 969                         return 1;
 970
 971                 /*
 972                  * Let ia64_do_page_fault() fix it.
 973                  */
 974                 break;
 975         default:
 976                 break;
 977         }
 978
 979         return 0;
 980 }
 981
 982 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 983                                        unsigned long val, void *data)
 984 {
 985         struct die_args *args = (struct die_args *)data;
 986         int ret = NOTIFY_DONE;
 987
 988         if (args->regs && user_mode(args->regs))
 989                 return ret;
 990
 991         switch(val) {
 992         case DIE_BREAK:
 993                 /* err is break number from ia64_bad_break() */
 994                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
 995                         || args->err == __IA64_BREAK_JPROBE
 996                         || args->err == 0)
 997                         if (pre_kprobes_handler(args))
 998                                 ret = NOTIFY_STOP;
 999                 break;
1000         case DIE_FAULT:
1001                 /* err is vector number from ia64_fault() */
1002                 if (args->err == 36)
1003                         if (post_kprobes_handler(args->regs))
1004                                 ret = NOTIFY_STOP;
1005                 break;
1006         default:
1007                 break;
1008         }
1009         return ret;
1010 }
1011
1012 struct param_bsp_cfm {
1013         unsigned long ip;
1014         unsigned long *bsp;
1015         unsigned long cfm;
1016 };
1017
1018 static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
1019 {
1020         unsigned long ip;
1021         struct param_bsp_cfm *lp = arg;
1022
1023         do {
1024                 unw_get_ip(info, &ip);
1025                 if (ip == 0)
1026                         break;
1027                 if (ip == lp->ip) {
1028                         unw_get_bsp(info, (unsigned long*)&lp->bsp);
1029                         unw_get_cfm(info, (unsigned long*)&lp->cfm);
1030                         return;
1031                 }
1032         } while (unw_unwind(info) >= 0);
1033         lp->bsp = NULL;
1034         lp->cfm = 0;
1035         return;
1036 }
1037
1038 unsigned long arch_deref_entry_point(void *entry)
1039 {
1040         return ((struct fnptr *)entry)->ip;
1041 }
1042
1043 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
1044 {
1045         struct jprobe *jp = container_of(p, struct jprobe, kp);
1046         unsigned long addr = arch_deref_entry_point(jp->entry);
1047         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1048         struct param_bsp_cfm pa;
1049         int bytes;
1050
1051         /*
1052          * Callee owns the argument space and could overwrite it, eg
1053          * tail call optimization. So to be absolutely safe
1054          * we save the argument space before transferring the control
1055          * to instrumented jprobe function which runs in
1056          * the process context
1057          */
1058         pa.ip = regs->cr_iip;
1059         unw_init_running(ia64_get_bsp_cfm, &pa);
1060         bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
1061                                 - (char *)pa.bsp;
1062         memcpy( kcb->jprobes_saved_stacked_regs,
1063                 pa.bsp,
1064                 bytes );
1065         kcb->bsp = pa.bsp;
1066         kcb->cfm = pa.cfm;
1067
1068         /* save architectural state */
1069         kcb->jprobe_saved_regs = *regs;
1070
1071         /* after rfi, execute the jprobe instrumented function */
1072         regs->cr_iip = addr & ~0xFULL;
1073         ia64_psr(regs)->ri = addr & 0xf;
1074         regs->r1 = ((struct fnptr *)(jp->entry))->gp;
1075
1076         /*
1077          * fix the return address to our jprobe_inst_return() function
1078          * in the jprobes.S file
1079          */
1080         regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
1081
1082         return 1;
1083 }
1084
1085 /* ia64 does not need this */
1086 void __kprobes jprobe_return(void)
1087 {
1088 }
1089
1090 int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
1091 {
1092         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1093         int bytes;
1094
1095         /* restoring architectural state */
1096         *regs = kcb->jprobe_saved_regs;
1097
1098         /* restoring the original argument space */
1099         flush_register_stack();
1100         bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
1101                                 - (char *)kcb->bsp;
1102         memcpy( kcb->bsp,
1103                 kcb->jprobes_saved_stacked_regs,
1104                 bytes );
1105         invalidate_stacked_regs();
1106
1107         preempt_enable_no_resched();
1108         return 1;
1109 }
1110
1111 static struct kprobe trampoline_p = {
1112         .pre_handler = trampoline_probe_handler
1113 };
1114
1115 int __init arch_init_kprobes(void)
1116 {
1117         trampoline_p.addr =
1118                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1119         return register_kprobe(&trampoline_p);
1120 }
1121
1122 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1123 {
1124         if (p->addr ==
1125                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1126                 return 1;
1127
1128         return 0;
1129 }