arch/ia64/kernel/kprobes.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
set_brl_inst
update_kprobe_inst_flag
is_cmp_ctype_unc_inst
unsupported_inst
prepare_break_inst
get_kprobe_inst
in_ivt_functions
valid_kprobe_addr
save_previous_kprobe
restore_previous_kprobe
set_current_kprobe
kretprobe_trampoline
trampoline_probe_handler
arch_prepare_kretprobe
__is_ia64_break_inst
can_boost
prepare_booster
arch_prepare_kprobe
arch_arm_kprobe
arch_disarm_kprobe
arch_remove_kprobe
resume_execution
prepare_ss
is_ia64_break_inst
pre_kprobes_handler
post_kprobes_handler
kprobe_fault_handler
kprobe_exceptions_notify
arch_deref_entry_point
arch_init_kprobes
arch_trampoline_kprobe
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Kernel Probes (KProbes)
   4  *  arch/ia64/kernel/kprobes.c
   5  *
   6  * Copyright (C) IBM Corporation, 2002, 2004
   7  * Copyright (C) Intel Corporation, 2005
   8  *
   9  * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
  10  *              <anil.s.keshavamurthy@intel.com> adapted from i386
  11  */
  12 
  13 #include <linux/kprobes.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/string.h>
  16 #include <linux/slab.h>
  17 #include <linux/preempt.h>
  18 #include <linux/extable.h>
  19 #include <linux/kdebug.h>
  20 
  21 #include <asm/pgtable.h>
  22 #include <asm/sections.h>
  23 #include <asm/exception.h>
  24 
  25 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
  26 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
  27 
  28 struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
  29 
  30 enum instruction_type {A, I, M, F, B, L, X, u};
  31 static enum instruction_type bundle_encoding[32][3] = {
  32   { M, I, I },                          /* 00 */
  33   { M, I, I },                          /* 01 */
  34   { M, I, I },                          /* 02 */
  35   { M, I, I },                          /* 03 */
  36   { M, L, X },                          /* 04 */
  37   { M, L, X },                          /* 05 */
  38   { u, u, u },                          /* 06 */
  39   { u, u, u },                          /* 07 */
  40   { M, M, I },                          /* 08 */
  41   { M, M, I },                          /* 09 */
  42   { M, M, I },                          /* 0A */
  43   { M, M, I },                          /* 0B */
  44   { M, F, I },                          /* 0C */
  45   { M, F, I },                          /* 0D */
  46   { M, M, F },                          /* 0E */
  47   { M, M, F },                          /* 0F */
  48   { M, I, B },                          /* 10 */
  49   { M, I, B },                          /* 11 */
  50   { M, B, B },                          /* 12 */
  51   { M, B, B },                          /* 13 */
  52   { u, u, u },                          /* 14 */
  53   { u, u, u },                          /* 15 */
  54   { B, B, B },                          /* 16 */
  55   { B, B, B },                          /* 17 */
  56   { M, M, B },                          /* 18 */
  57   { M, M, B },                          /* 19 */
  58   { u, u, u },                          /* 1A */
  59   { u, u, u },                          /* 1B */
  60   { M, F, B },                          /* 1C */
  61   { M, F, B },                          /* 1D */
  62   { u, u, u },                          /* 1E */
  63   { u, u, u },                          /* 1F */
  64 };
  65 
  66 /* Insert a long branch code */
  67 static void __kprobes set_brl_inst(void *from, void *to)
  68 {
  69         s64 rel = ((s64) to - (s64) from) >> 4;
  70         bundle_t *brl;
  71         brl = (bundle_t *) ((u64) from & ~0xf);
  72         brl->quad0.template = 0x05;     /* [MLX](stop) */
  73         brl->quad0.slot0 = NOP_M_INST;  /* nop.m 0x0 */
  74         brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
  75         brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
  76         /* brl.cond.sptk.many.clr rel<<4 (qp=0) */
  77         brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
  78 }
  79 
  80 /*
  81  * In this function we check to see if the instruction
  82  * is IP relative instruction and update the kprobe
  83  * inst flag accordingly
  84  */
  85 static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
  86                                               uint major_opcode,
  87                                               unsigned long kprobe_inst,
  88                                               struct kprobe *p)
  89 {
  90         p->ainsn.inst_flag = 0;
  91         p->ainsn.target_br_reg = 0;
  92         p->ainsn.slot = slot;
  93 
  94         /* Check for Break instruction
  95          * Bits 37:40 Major opcode to be zero
  96          * Bits 27:32 X6 to be zero
  97          * Bits 32:35 X3 to be zero
  98          */
  99         if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
 100                 /* is a break instruction */
 101                 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
 102                 return;
 103         }
 104 
 105         if (bundle_encoding[template][slot] == B) {
 106                 switch (major_opcode) {
 107                   case INDIRECT_CALL_OPCODE:
 108                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 109                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 110                         break;
 111                   case IP_RELATIVE_PREDICT_OPCODE:
 112                   case IP_RELATIVE_BRANCH_OPCODE:
 113                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 114                         break;
 115                   case IP_RELATIVE_CALL_OPCODE:
 116                         p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
 117                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 118                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 119                         break;
 120                 }
 121         } else if (bundle_encoding[template][slot] == X) {
 122                 switch (major_opcode) {
 123                   case LONG_CALL_OPCODE:
 124                         p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
 125                         p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
 126                   break;
 127                 }
 128         }
 129         return;
 130 }
 131 
 132 /*
 133  * In this function we check to see if the instruction
 134  * (qp) cmpx.crel.ctype p1,p2=r2,r3
 135  * on which we are inserting kprobe is cmp instruction
 136  * with ctype as unc.
 137  */
 138 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
 139                                             uint major_opcode,
 140                                             unsigned long kprobe_inst)
 141 {
 142         cmp_inst_t cmp_inst;
 143         uint ctype_unc = 0;
 144 
 145         if (!((bundle_encoding[template][slot] == I) ||
 146                 (bundle_encoding[template][slot] == M)))
 147                 goto out;
 148 
 149         if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
 150                 (major_opcode == 0xE)))
 151                 goto out;
 152 
 153         cmp_inst.l = kprobe_inst;
 154         if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
 155                 /* Integer compare - Register Register (A6 type)*/
 156                 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
 157                                 &&(cmp_inst.f.c == 1))
 158                         ctype_unc = 1;
 159         } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
 160                 /* Integer compare - Immediate Register (A8 type)*/
 161                 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
 162                         ctype_unc = 1;
 163         }
 164 out:
 165         return ctype_unc;
 166 }
 167 
 168 /*
 169  * In this function we check to see if the instruction
 170  * on which we are inserting kprobe is supported.
 171  * Returns qp value if supported
 172  * Returns -EINVAL if unsupported
 173  */
 174 static int __kprobes unsupported_inst(uint template, uint  slot,
 175                                       uint major_opcode,
 176                                       unsigned long kprobe_inst,
 177                                       unsigned long addr)
 178 {
 179         int qp;
 180 
 181         qp = kprobe_inst & 0x3f;
 182         if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
 183                 if (slot == 1 && qp)  {
 184                         printk(KERN_WARNING "Kprobes on cmp unc "
 185                                         "instruction on slot 1 at <0x%lx> "
 186                                         "is not supported\n", addr);
 187                         return -EINVAL;
 188 
 189                 }
 190                 qp = 0;
 191         }
 192         else if (bundle_encoding[template][slot] == I) {
 193                 if (major_opcode == 0) {
 194                         /*
 195                          * Check for Integer speculation instruction
 196                          * - Bit 33-35 to be equal to 0x1
 197                          */
 198                         if (((kprobe_inst >> 33) & 0x7) == 1) {
 199                                 printk(KERN_WARNING
 200                                         "Kprobes on speculation inst at <0x%lx> not supported\n",
 201                                                 addr);
 202                                 return -EINVAL;
 203                         }
 204                         /*
 205                          * IP relative mov instruction
 206                          *  - Bit 27-35 to be equal to 0x30
 207                          */
 208                         if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
 209                                 printk(KERN_WARNING
 210                                         "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
 211                                                 addr);
 212                                 return -EINVAL;
 213 
 214                         }
 215                 }
 216                 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
 217                                 (kprobe_inst & (0x1UL << 12))) {
 218                         /* test bit instructions, tbit,tnat,tf
 219                          * bit 33-36 to be equal to 0
 220                          * bit 12 to be equal to 1
 221                          */
 222                         if (slot == 1 && qp) {
 223                                 printk(KERN_WARNING "Kprobes on test bit "
 224                                                 "instruction on slot at <0x%lx> "
 225                                                 "is not supported\n", addr);
 226                                 return -EINVAL;
 227                         }
 228                         qp = 0;
 229                 }
 230         }
 231         else if (bundle_encoding[template][slot] == B) {
 232                 if (major_opcode == 7) {
 233                         /* IP-Relative Predict major code is 7 */
 234                         printk(KERN_WARNING "Kprobes on IP-Relative"
 235                                         "Predict is not supported\n");
 236                         return -EINVAL;
 237                 }
 238                 else if (major_opcode == 2) {
 239                         /* Indirect Predict, major code is 2
 240                          * bit 27-32 to be equal to 10 or 11
 241                          */
 242                         int x6=(kprobe_inst >> 27) & 0x3F;
 243                         if ((x6 == 0x10) || (x6 == 0x11)) {
 244                                 printk(KERN_WARNING "Kprobes on "
 245                                         "Indirect Predict is not supported\n");
 246                                 return -EINVAL;
 247                         }
 248                 }
 249         }
 250         /* kernel does not use float instruction, here for safety kprobe
 251          * will judge whether it is fcmp/flass/float approximation instruction
 252          */
 253         else if (unlikely(bundle_encoding[template][slot] == F)) {
 254                 if ((major_opcode == 4 || major_opcode == 5) &&
 255                                 (kprobe_inst  & (0x1 << 12))) {
 256                         /* fcmp/fclass unc instruction */
 257                         if (slot == 1 && qp) {
 258                                 printk(KERN_WARNING "Kprobes on fcmp/fclass "
 259                                         "instruction on slot at <0x%lx> "
 260                                         "is not supported\n", addr);
 261                                 return -EINVAL;
 262 
 263                         }
 264                         qp = 0;
 265                 }
 266                 if ((major_opcode == 0 || major_opcode == 1) &&
 267                         (kprobe_inst & (0x1UL << 33))) {
 268                         /* float Approximation instruction */
 269                         if (slot == 1 && qp) {
 270                                 printk(KERN_WARNING "Kprobes on float Approx "
 271                                         "instr at <0x%lx> is not supported\n",
 272                                                 addr);
 273                                 return -EINVAL;
 274                         }
 275                         qp = 0;
 276                 }
 277         }
 278         return qp;
 279 }
 280 
 281 /*
 282  * In this function we override the bundle with
 283  * the break instruction at the given slot.
 284  */
 285 static void __kprobes prepare_break_inst(uint template, uint  slot,
 286                                          uint major_opcode,
 287                                          unsigned long kprobe_inst,
 288                                          struct kprobe *p,
 289                                          int qp)
 290 {
 291         unsigned long break_inst = BREAK_INST;
 292         bundle_t *bundle = &p->opcode.bundle;
 293 
 294         /*
 295          * Copy the original kprobe_inst qualifying predicate(qp)
 296          * to the break instruction
 297          */
 298         break_inst |= qp;
 299 
 300         switch (slot) {
 301           case 0:
 302                 bundle->quad0.slot0 = break_inst;
 303                 break;
 304           case 1:
 305                 bundle->quad0.slot1_p0 = break_inst;
 306                 bundle->quad1.slot1_p1 = break_inst >> (64-46);
 307                 break;
 308           case 2:
 309                 bundle->quad1.slot2 = break_inst;
 310                 break;
 311         }
 312 
 313         /*
 314          * Update the instruction flag, so that we can
 315          * emulate the instruction properly after we
 316          * single step on original instruction
 317          */
 318         update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
 319 }
 320 
 321 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
 322                 unsigned long *kprobe_inst, uint *major_opcode)
 323 {
 324         unsigned long kprobe_inst_p0, kprobe_inst_p1;
 325         unsigned int template;
 326 
 327         template = bundle->quad0.template;
 328 
 329         switch (slot) {
 330           case 0:
 331                 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
 332                 *kprobe_inst = bundle->quad0.slot0;
 333                   break;
 334           case 1:
 335                 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
 336                 kprobe_inst_p0 = bundle->quad0.slot1_p0;
 337                 kprobe_inst_p1 = bundle->quad1.slot1_p1;
 338                 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
 339                 break;
 340           case 2:
 341                 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
 342                 *kprobe_inst = bundle->quad1.slot2;
 343                 break;
 344         }
 345 }
 346 
 347 /* Returns non-zero if the addr is in the Interrupt Vector Table */
 348 static int __kprobes in_ivt_functions(unsigned long addr)
 349 {
 350         return (addr >= (unsigned long)__start_ivt_text
 351                 && addr < (unsigned long)__end_ivt_text);
 352 }
 353 
 354 static int __kprobes valid_kprobe_addr(int template, int slot,
 355                                        unsigned long addr)
 356 {
 357         if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
 358                 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
 359                                 "at 0x%lx\n", addr);
 360                 return -EINVAL;
 361         }
 362 
 363         if (in_ivt_functions(addr)) {
 364                 printk(KERN_WARNING "Kprobes can't be inserted inside "
 365                                 "IVT functions at 0x%lx\n", addr);
 366                 return -EINVAL;
 367         }
 368 
 369         return 0;
 370 }
 371 
 372 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
 373 {
 374         unsigned int i;
 375         i = atomic_add_return(1, &kcb->prev_kprobe_index);
 376         kcb->prev_kprobe[i-1].kp = kprobe_running();
 377         kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
 378 }
 379 
 380 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 381 {
 382         unsigned int i;
 383         i = atomic_read(&kcb->prev_kprobe_index);
 384         __this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp);
 385         kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
 386         atomic_sub(1, &kcb->prev_kprobe_index);
 387 }
 388 
 389 static void __kprobes set_current_kprobe(struct kprobe *p,
 390                         struct kprobe_ctlblk *kcb)
 391 {
 392         __this_cpu_write(current_kprobe, p);
 393 }
 394 
 395 static void kretprobe_trampoline(void)
 396 {
 397 }
 398 
 399 /*
 400  * At this point the target function has been tricked into
 401  * returning into our trampoline.  Lookup the associated instance
 402  * and then:
 403  *    - call the handler function
 404  *    - cleanup by marking the instance as unused
 405  *    - long jump back to the original return address
 406  */
 407 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 408 {
 409         struct kretprobe_instance *ri = NULL;
 410         struct hlist_head *head, empty_rp;
 411         struct hlist_node *tmp;
 412         unsigned long flags, orig_ret_address = 0;
 413         unsigned long trampoline_address =
 414                 ((struct fnptr *)kretprobe_trampoline)->ip;
 415 
 416         INIT_HLIST_HEAD(&empty_rp);
 417         kretprobe_hash_lock(current, &head, &flags);
 418 
 419         /*
 420          * It is possible to have multiple instances associated with a given
 421          * task either because an multiple functions in the call path
 422          * have a return probe installed on them, and/or more than one return
 423          * return probe was registered for a target function.
 424          *
 425          * We can handle this because:
 426          *     - instances are always inserted at the head of the list
 427          *     - when multiple return probes are registered for the same
 428          *       function, the first instance's ret_addr will point to the
 429          *       real return address, and all the rest will point to
 430          *       kretprobe_trampoline
 431          */
 432         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 433                 if (ri->task != current)
 434                         /* another task is sharing our hash bucket */
 435                         continue;
 436 
 437                 orig_ret_address = (unsigned long)ri->ret_addr;
 438                 if (orig_ret_address != trampoline_address)
 439                         /*
 440                          * This is the real return address. Any other
 441                          * instances associated with this task are for
 442                          * other calls deeper on the call stack
 443                          */
 444                         break;
 445         }
 446 
 447         regs->cr_iip = orig_ret_address;
 448 
 449         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
 450                 if (ri->task != current)
 451                         /* another task is sharing our hash bucket */
 452                         continue;
 453 
 454                 if (ri->rp && ri->rp->handler)
 455                         ri->rp->handler(ri, regs);
 456 
 457                 orig_ret_address = (unsigned long)ri->ret_addr;
 458                 recycle_rp_inst(ri, &empty_rp);
 459 
 460                 if (orig_ret_address != trampoline_address)
 461                         /*
 462                          * This is the real return address. Any other
 463                          * instances associated with this task are for
 464                          * other calls deeper on the call stack
 465                          */
 466                         break;
 467         }
 468         kretprobe_assert(ri, orig_ret_address, trampoline_address);
 469 
 470         kretprobe_hash_unlock(current, &flags);
 471 
 472         hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
 473                 hlist_del(&ri->hlist);
 474                 kfree(ri);
 475         }
 476         /*
 477          * By returning a non-zero value, we are telling
 478          * kprobe_handler() that we don't want the post_handler
 479          * to run (and have re-enabled preemption)
 480          */
 481         return 1;
 482 }
 483 
 484 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 485                                       struct pt_regs *regs)
 486 {
 487         ri->ret_addr = (kprobe_opcode_t *)regs->b0;
 488 
 489         /* Replace the return addr with trampoline addr */
 490         regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
 491 }
 492 
 493 /* Check the instruction in the slot is break */
 494 static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
 495 {
 496         unsigned int major_opcode;
 497         unsigned int template = bundle->quad0.template;
 498         unsigned long kprobe_inst;
 499 
 500         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 501         if (slot == 1 && bundle_encoding[template][1] == L)
 502                 slot++;
 503 
 504         /* Get Kprobe probe instruction at given slot*/
 505         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 506 
 507         /* For break instruction,
 508          * Bits 37:40 Major opcode to be zero
 509          * Bits 27:32 X6 to be zero
 510          * Bits 32:35 X3 to be zero
 511          */
 512         if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
 513                 /* Not a break instruction */
 514                 return 0;
 515         }
 516 
 517         /* Is a break instruction */
 518         return 1;
 519 }
 520 
 521 /*
 522  * In this function, we check whether the target bundle modifies IP or
 523  * it triggers an exception. If so, it cannot be boostable.
 524  */
 525 static int __kprobes can_boost(bundle_t *bundle, uint slot,
 526                                unsigned long bundle_addr)
 527 {
 528         unsigned int template = bundle->quad0.template;
 529 
 530         do {
 531                 if (search_exception_tables(bundle_addr + slot) ||
 532                     __is_ia64_break_inst(bundle, slot))
 533                         return 0;       /* exception may occur in this bundle*/
 534         } while ((++slot) < 3);
 535         template &= 0x1e;
 536         if (template >= 0x10 /* including B unit */ ||
 537             template == 0x04 /* including X unit */ ||
 538             template == 0x06) /* undefined */
 539                 return 0;
 540 
 541         return 1;
 542 }
 543 
 544 /* Prepare long jump bundle and disables other boosters if need */
 545 static void __kprobes prepare_booster(struct kprobe *p)
 546 {
 547         unsigned long addr = (unsigned long)p->addr & ~0xFULL;
 548         unsigned int slot = (unsigned long)p->addr & 0xf;
 549         struct kprobe *other_kp;
 550 
 551         if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
 552                 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
 553                 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
 554         }
 555 
 556         /* disables boosters in previous slots */
 557         for (; addr < (unsigned long)p->addr; addr++) {
 558                 other_kp = get_kprobe((void *)addr);
 559                 if (other_kp)
 560                         other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
 561         }
 562 }
 563 
 564 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 565 {
 566         unsigned long addr = (unsigned long) p->addr;
 567         unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
 568         unsigned long kprobe_inst=0;
 569         unsigned int slot = addr & 0xf, template, major_opcode = 0;
 570         bundle_t *bundle;
 571         int qp;
 572 
 573         bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
 574         template = bundle->quad0.template;
 575 
 576         if(valid_kprobe_addr(template, slot, addr))
 577                 return -EINVAL;
 578 
 579         /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
 580         if (slot == 1 && bundle_encoding[template][1] == L)
 581                 slot++;
 582 
 583         /* Get kprobe_inst and major_opcode from the bundle */
 584         get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
 585 
 586         qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
 587         if (qp < 0)
 588                 return -EINVAL;
 589 
 590         p->ainsn.insn = get_insn_slot();
 591         if (!p->ainsn.insn)
 592                 return -ENOMEM;
 593         memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
 594         memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
 595 
 596         prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
 597 
 598         prepare_booster(p);
 599 
 600         return 0;
 601 }
 602 
 603 void __kprobes arch_arm_kprobe(struct kprobe *p)
 604 {
 605         unsigned long arm_addr;
 606         bundle_t *src, *dest;
 607 
 608         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 609         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 610         src = &p->opcode.bundle;
 611 
 612         flush_icache_range((unsigned long)p->ainsn.insn,
 613                            (unsigned long)p->ainsn.insn +
 614                            sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
 615 
 616         switch (p->ainsn.slot) {
 617                 case 0:
 618                         dest->quad0.slot0 = src->quad0.slot0;
 619                         break;
 620                 case 1:
 621                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 622                         break;
 623                 case 2:
 624                         dest->quad1.slot2 = src->quad1.slot2;
 625                         break;
 626         }
 627         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 628 }
 629 
 630 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 631 {
 632         unsigned long arm_addr;
 633         bundle_t *src, *dest;
 634 
 635         arm_addr = ((unsigned long)p->addr) & ~0xFUL;
 636         dest = &((kprobe_opcode_t *)arm_addr)->bundle;
 637         /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
 638         src = &p->ainsn.insn->bundle;
 639         switch (p->ainsn.slot) {
 640                 case 0:
 641                         dest->quad0.slot0 = src->quad0.slot0;
 642                         break;
 643                 case 1:
 644                         dest->quad1.slot1_p1 = src->quad1.slot1_p1;
 645                         break;
 646                 case 2:
 647                         dest->quad1.slot2 = src->quad1.slot2;
 648                         break;
 649         }
 650         flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
 651 }
 652 
 653 void __kprobes arch_remove_kprobe(struct kprobe *p)
 654 {
 655         if (p->ainsn.insn) {
 656                 free_insn_slot(p->ainsn.insn,
 657                                p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
 658                 p->ainsn.insn = NULL;
 659         }
 660 }
 661 /*
 662  * We are resuming execution after a single step fault, so the pt_regs
 663  * structure reflects the register state after we executed the instruction
 664  * located in the kprobe (p->ainsn.insn->bundle).  We still need to adjust
 665  * the ip to point back to the original stack address. To set the IP address
 666  * to original stack address, handle the case where we need to fixup the
 667  * relative IP address and/or fixup branch register.
 668  */
 669 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
 670 {
 671         unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
 672         unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
 673         unsigned long template;
 674         int slot = ((unsigned long)p->addr & 0xf);
 675 
 676         template = p->ainsn.insn->bundle.quad0.template;
 677 
 678         if (slot == 1 && bundle_encoding[template][1] == L)
 679                 slot = 2;
 680 
 681         if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
 682 
 683                 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
 684                         /* Fix relative IP address */
 685                         regs->cr_iip = (regs->cr_iip - bundle_addr) +
 686                                         resume_addr;
 687                 }
 688 
 689                 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
 690                 /*
 691                  * Fix target branch register, software convention is
 692                  * to use either b0 or b6 or b7, so just checking
 693                  * only those registers
 694                  */
 695                         switch (p->ainsn.target_br_reg) {
 696                         case 0:
 697                                 if ((regs->b0 == bundle_addr) ||
 698                                         (regs->b0 == bundle_addr + 0x10)) {
 699                                         regs->b0 = (regs->b0 - bundle_addr) +
 700                                                 resume_addr;
 701                                 }
 702                                 break;
 703                         case 6:
 704                                 if ((regs->b6 == bundle_addr) ||
 705                                         (regs->b6 == bundle_addr + 0x10)) {
 706                                         regs->b6 = (regs->b6 - bundle_addr) +
 707                                                 resume_addr;
 708                                 }
 709                                 break;
 710                         case 7:
 711                                 if ((regs->b7 == bundle_addr) ||
 712                                         (regs->b7 == bundle_addr + 0x10)) {
 713                                         regs->b7 = (regs->b7 - bundle_addr) +
 714                                                 resume_addr;
 715                                 }
 716                                 break;
 717                         } /* end switch */
 718                 }
 719                 goto turn_ss_off;
 720         }
 721 
 722         if (slot == 2) {
 723                 if (regs->cr_iip == bundle_addr + 0x10) {
 724                         regs->cr_iip = resume_addr + 0x10;
 725                 }
 726         } else {
 727                 if (regs->cr_iip == bundle_addr) {
 728                         regs->cr_iip = resume_addr;
 729                 }
 730         }
 731 
 732 turn_ss_off:
 733         /* Turn off Single Step bit */
 734         ia64_psr(regs)->ss = 0;
 735 }
 736 
 737 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
 738 {
 739         unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
 740         unsigned long slot = (unsigned long)p->addr & 0xf;
 741 
 742         /* single step inline if break instruction */
 743         if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
 744                 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
 745         else
 746                 regs->cr_iip = bundle_addr & ~0xFULL;
 747 
 748         if (slot > 2)
 749                 slot = 0;
 750 
 751         ia64_psr(regs)->ri = slot;
 752 
 753         /* turn on single stepping */
 754         ia64_psr(regs)->ss = 1;
 755 }
 756 
 757 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
 758 {
 759         unsigned int slot = ia64_psr(regs)->ri;
 760         unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
 761         bundle_t bundle;
 762 
 763         memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
 764 
 765         return __is_ia64_break_inst(&bundle, slot);
 766 }
 767 
 768 static int __kprobes pre_kprobes_handler(struct die_args *args)
 769 {
 770         struct kprobe *p;
 771         int ret = 0;
 772         struct pt_regs *regs = args->regs;
 773         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 774         struct kprobe_ctlblk *kcb;
 775 
 776         /*
 777          * We don't want to be preempted for the entire
 778          * duration of kprobe processing
 779          */
 780         preempt_disable();
 781         kcb = get_kprobe_ctlblk();
 782 
 783         /* Handle recursion cases */
 784         if (kprobe_running()) {
 785                 p = get_kprobe(addr);
 786                 if (p) {
 787                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
 788                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
 789                                 ia64_psr(regs)->ss = 0;
 790                                 goto no_kprobe;
 791                         }
 792                         /* We have reentered the pre_kprobe_handler(), since
 793                          * another probe was hit while within the handler.
 794                          * We here save the original kprobes variables and
 795                          * just single step on the instruction of the new probe
 796                          * without calling any user handlers.
 797                          */
 798                         save_previous_kprobe(kcb);
 799                         set_current_kprobe(p, kcb);
 800                         kprobes_inc_nmissed_count(p);
 801                         prepare_ss(p, regs);
 802                         kcb->kprobe_status = KPROBE_REENTER;
 803                         return 1;
 804                 } else if (!is_ia64_break_inst(regs)) {
 805                         /* The breakpoint instruction was removed by
 806                          * another cpu right after we hit, no further
 807                          * handling of this interrupt is appropriate
 808                          */
 809                         ret = 1;
 810                         goto no_kprobe;
 811                 } else {
 812                         /* Not our break */
 813                         goto no_kprobe;
 814                 }
 815         }
 816 
 817         p = get_kprobe(addr);
 818         if (!p) {
 819                 if (!is_ia64_break_inst(regs)) {
 820                         /*
 821                          * The breakpoint instruction was removed right
 822                          * after we hit it.  Another cpu has removed
 823                          * either a probepoint or a debugger breakpoint
 824                          * at this address.  In either case, no further
 825                          * handling of this interrupt is appropriate.
 826                          */
 827                         ret = 1;
 828 
 829                 }
 830 
 831                 /* Not one of our break, let kernel handle it */
 832                 goto no_kprobe;
 833         }
 834 
 835         set_current_kprobe(p, kcb);
 836         kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 837 
 838         if (p->pre_handler && p->pre_handler(p, regs)) {
 839                 reset_current_kprobe();
 840                 preempt_enable_no_resched();
 841                 return 1;
 842         }
 843 
 844 #if !defined(CONFIG_PREEMPT)
 845         if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
 846                 /* Boost up -- we can execute copied instructions directly */
 847                 ia64_psr(regs)->ri = p->ainsn.slot;
 848                 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
 849                 /* turn single stepping off */
 850                 ia64_psr(regs)->ss = 0;
 851 
 852                 reset_current_kprobe();
 853                 preempt_enable_no_resched();
 854                 return 1;
 855         }
 856 #endif
 857         prepare_ss(p, regs);
 858         kcb->kprobe_status = KPROBE_HIT_SS;
 859         return 1;
 860 
 861 no_kprobe:
 862         preempt_enable_no_resched();
 863         return ret;
 864 }
 865 
 866 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
 867 {
 868         struct kprobe *cur = kprobe_running();
 869         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 870 
 871         if (!cur)
 872                 return 0;
 873 
 874         if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
 875                 kcb->kprobe_status = KPROBE_HIT_SSDONE;
 876                 cur->post_handler(cur, regs, 0);
 877         }
 878 
 879         resume_execution(cur, regs);
 880 
 881         /*Restore back the original saved kprobes variables and continue. */
 882         if (kcb->kprobe_status == KPROBE_REENTER) {
 883                 restore_previous_kprobe(kcb);
 884                 goto out;
 885         }
 886         reset_current_kprobe();
 887 
 888 out:
 889         preempt_enable_no_resched();
 890         return 1;
 891 }
 892 
 893 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 894 {
 895         struct kprobe *cur = kprobe_running();
 896         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 897 
 898 
 899         switch(kcb->kprobe_status) {
 900         case KPROBE_HIT_SS:
 901         case KPROBE_REENTER:
 902                 /*
 903                  * We are here because the instruction being single
 904                  * stepped caused a page fault. We reset the current
 905                  * kprobe and the instruction pointer points back to
 906                  * the probe address and allow the page fault handler
 907                  * to continue as a normal page fault.
 908                  */
 909                 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
 910                 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
 911                 if (kcb->kprobe_status == KPROBE_REENTER)
 912                         restore_previous_kprobe(kcb);
 913                 else
 914                         reset_current_kprobe();
 915                 preempt_enable_no_resched();
 916                 break;
 917         case KPROBE_HIT_ACTIVE:
 918         case KPROBE_HIT_SSDONE:
 919                 /*
 920                  * We increment the nmissed count for accounting,
 921                  * we can also use npre/npostfault count for accounting
 922                  * these specific fault cases.
 923                  */
 924                 kprobes_inc_nmissed_count(cur);
 925 
 926                 /*
 927                  * We come here because instructions in the pre/post
 928                  * handler caused the page_fault, this could happen
 929                  * if handler tries to access user space by
 930                  * copy_from_user(), get_user() etc. Let the
 931                  * user-specified handler try to fix it first.
 932                  */
 933                 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
 934                         return 1;
 935                 /*
 936                  * In case the user-specified fault handler returned
 937                  * zero, try to fix up.
 938                  */
 939                 if (ia64_done_with_exception(regs))
 940                         return 1;
 941 
 942                 /*
 943                  * Let ia64_do_page_fault() fix it.
 944                  */
 945                 break;
 946         default:
 947                 break;
 948         }
 949 
 950         return 0;
 951 }
 952 
 953 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 954                                        unsigned long val, void *data)
 955 {
 956         struct die_args *args = (struct die_args *)data;
 957         int ret = NOTIFY_DONE;
 958 
 959         if (args->regs && user_mode(args->regs))
 960                 return ret;
 961 
 962         switch(val) {
 963         case DIE_BREAK:
 964                 /* err is break number from ia64_bad_break() */
 965                 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
 966                         || args->err == 0)
 967                         if (pre_kprobes_handler(args))
 968                                 ret = NOTIFY_STOP;
 969                 break;
 970         case DIE_FAULT:
 971                 /* err is vector number from ia64_fault() */
 972                 if (args->err == 36)
 973                         if (post_kprobes_handler(args->regs))
 974                                 ret = NOTIFY_STOP;
 975                 break;
 976         default:
 977                 break;
 978         }
 979         return ret;
 980 }
 981 
 982 unsigned long arch_deref_entry_point(void *entry)
 983 {
 984         return ((struct fnptr *)entry)->ip;
 985 }
 986 
 987 static struct kprobe trampoline_p = {
 988         .pre_handler = trampoline_probe_handler
 989 };
 990 
 991 int __init arch_init_kprobes(void)
 992 {
 993         trampoline_p.addr =
 994                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
 995         return register_kprobe(&trampoline_p);
 996 }
 997 
 998 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 999 {
1000         if (p->addr ==
1001                 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1002                 return 1;
1003 
1004         return 0;
1005 }
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root/arch/ia64/kernel/kprobes.c

DEFINITIONS
