linux/arch/ia64/kernel/kprobes.c
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   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
  38extern void jprobe_inst_return(void);
  39
  40DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
  41DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
  42
  43struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
  44
  45enum instruction_type {A, I, M, F, B, L, X, u};
  46static 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 */
  82static 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 */
 100static 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 */
 153static 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        }
 179out:
 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 */
 189static 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 */
 300static 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
 336static 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 */
 363static 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
 369static 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
 387static 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
 395static 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
 404static void __kprobes set_current_kprobe(struct kprobe *p,
 405                        struct kprobe_ctlblk *kcb)
 406{
 407        __this_cpu_write(current_kprobe, p);
 408}
 409
 410static 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 */
 422int __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
 502void __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 */
 512static 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 */
 543static 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 */
 563static 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
 582int __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
 621void __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
 648void __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
 671void __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 */
 687static 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
 750turn_ss_off:
 751        /* Turn off Single Step bit */
 752        ia64_psr(regs)->ss = 0;
 753}
 754
 755static 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
 775static 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
 786static 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
 872ss_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
 890no_kprobe:
 891        preempt_enable_no_resched();
 892        return ret;
 893}
 894
 895static 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
 917out:
 918        preempt_enable_no_resched();
 919        return 1;
 920}
 921
 922int __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
 982int __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
1012struct param_bsp_cfm {
1013        unsigned long ip;
1014        unsigned long *bsp;
1015        unsigned long cfm;
1016};
1017
1018static 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
1038unsigned long arch_deref_entry_point(void *entry)
1039{
1040        return ((struct fnptr *)entry)->ip;
1041}
1042
1043int __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 */
1086void __kprobes jprobe_return(void)
1087{
1088}
1089
1090int __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
1111static struct kprobe trampoline_p = {
1112        .pre_handler = trampoline_probe_handler
1113};
1114
1115int __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
1122int __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}
1130