linux/arch/arm/kernel/ptrace.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/arch/arm/kernel/ptrace.c
   4 *
   5 *  By Ross Biro 1/23/92
   6 * edited by Linus Torvalds
   7 * ARM modifications Copyright (C) 2000 Russell King
   8 */
   9#include <linux/kernel.h>
  10#include <linux/sched/signal.h>
  11#include <linux/sched/task_stack.h>
  12#include <linux/mm.h>
  13#include <linux/elf.h>
  14#include <linux/smp.h>
  15#include <linux/ptrace.h>
  16#include <linux/user.h>
  17#include <linux/security.h>
  18#include <linux/init.h>
  19#include <linux/signal.h>
  20#include <linux/uaccess.h>
  21#include <linux/perf_event.h>
  22#include <linux/hw_breakpoint.h>
  23#include <linux/regset.h>
  24#include <linux/audit.h>
  25#include <linux/tracehook.h>
  26#include <linux/unistd.h>
  27
  28#include <asm/pgtable.h>
  29#include <asm/traps.h>
  30
  31#define CREATE_TRACE_POINTS
  32#include <trace/events/syscalls.h>
  33
  34#define REG_PC  15
  35#define REG_PSR 16
  36/*
  37 * does not yet catch signals sent when the child dies.
  38 * in exit.c or in signal.c.
  39 */
  40
  41#if 0
  42/*
  43 * Breakpoint SWI instruction: SWI &9F0001
  44 */
  45#define BREAKINST_ARM   0xef9f0001
  46#define BREAKINST_THUMB 0xdf00          /* fill this in later */
  47#else
  48/*
  49 * New breakpoints - use an undefined instruction.  The ARM architecture
  50 * reference manual guarantees that the following instruction space
  51 * will produce an undefined instruction exception on all CPUs:
  52 *
  53 *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
  54 *  Thumb: 1101 1110 xxxx xxxx
  55 */
  56#define BREAKINST_ARM   0xe7f001f0
  57#define BREAKINST_THUMB 0xde01
  58#endif
  59
  60struct pt_regs_offset {
  61        const char *name;
  62        int offset;
  63};
  64
  65#define REG_OFFSET_NAME(r) \
  66        {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
  67#define REG_OFFSET_END {.name = NULL, .offset = 0}
  68
  69static const struct pt_regs_offset regoffset_table[] = {
  70        REG_OFFSET_NAME(r0),
  71        REG_OFFSET_NAME(r1),
  72        REG_OFFSET_NAME(r2),
  73        REG_OFFSET_NAME(r3),
  74        REG_OFFSET_NAME(r4),
  75        REG_OFFSET_NAME(r5),
  76        REG_OFFSET_NAME(r6),
  77        REG_OFFSET_NAME(r7),
  78        REG_OFFSET_NAME(r8),
  79        REG_OFFSET_NAME(r9),
  80        REG_OFFSET_NAME(r10),
  81        REG_OFFSET_NAME(fp),
  82        REG_OFFSET_NAME(ip),
  83        REG_OFFSET_NAME(sp),
  84        REG_OFFSET_NAME(lr),
  85        REG_OFFSET_NAME(pc),
  86        REG_OFFSET_NAME(cpsr),
  87        REG_OFFSET_NAME(ORIG_r0),
  88        REG_OFFSET_END,
  89};
  90
  91/**
  92 * regs_query_register_offset() - query register offset from its name
  93 * @name:       the name of a register
  94 *
  95 * regs_query_register_offset() returns the offset of a register in struct
  96 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
  97 */
  98int regs_query_register_offset(const char *name)
  99{
 100        const struct pt_regs_offset *roff;
 101        for (roff = regoffset_table; roff->name != NULL; roff++)
 102                if (!strcmp(roff->name, name))
 103                        return roff->offset;
 104        return -EINVAL;
 105}
 106
 107/**
 108 * regs_query_register_name() - query register name from its offset
 109 * @offset:     the offset of a register in struct pt_regs.
 110 *
 111 * regs_query_register_name() returns the name of a register from its
 112 * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 113 */
 114const char *regs_query_register_name(unsigned int offset)
 115{
 116        const struct pt_regs_offset *roff;
 117        for (roff = regoffset_table; roff->name != NULL; roff++)
 118                if (roff->offset == offset)
 119                        return roff->name;
 120        return NULL;
 121}
 122
 123/**
 124 * regs_within_kernel_stack() - check the address in the stack
 125 * @regs:      pt_regs which contains kernel stack pointer.
 126 * @addr:      address which is checked.
 127 *
 128 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 129 * If @addr is within the kernel stack, it returns true. If not, returns false.
 130 */
 131bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 132{
 133        return ((addr & ~(THREAD_SIZE - 1))  ==
 134                (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 135}
 136
 137/**
 138 * regs_get_kernel_stack_nth() - get Nth entry of the stack
 139 * @regs:       pt_regs which contains kernel stack pointer.
 140 * @n:          stack entry number.
 141 *
 142 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 143 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 144 * this returns 0.
 145 */
 146unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 147{
 148        unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 149        addr += n;
 150        if (regs_within_kernel_stack(regs, (unsigned long)addr))
 151                return *addr;
 152        else
 153                return 0;
 154}
 155
 156/*
 157 * this routine will get a word off of the processes privileged stack.
 158 * the offset is how far from the base addr as stored in the THREAD.
 159 * this routine assumes that all the privileged stacks are in our
 160 * data space.
 161 */
 162static inline long get_user_reg(struct task_struct *task, int offset)
 163{
 164        return task_pt_regs(task)->uregs[offset];
 165}
 166
 167/*
 168 * this routine will put a word on the processes privileged stack.
 169 * the offset is how far from the base addr as stored in the THREAD.
 170 * this routine assumes that all the privileged stacks are in our
 171 * data space.
 172 */
 173static inline int
 174put_user_reg(struct task_struct *task, int offset, long data)
 175{
 176        struct pt_regs newregs, *regs = task_pt_regs(task);
 177        int ret = -EINVAL;
 178
 179        newregs = *regs;
 180        newregs.uregs[offset] = data;
 181
 182        if (valid_user_regs(&newregs)) {
 183                regs->uregs[offset] = data;
 184                ret = 0;
 185        }
 186
 187        return ret;
 188}
 189
 190/*
 191 * Called by kernel/ptrace.c when detaching..
 192 */
 193void ptrace_disable(struct task_struct *child)
 194{
 195        /* Nothing to do. */
 196}
 197
 198/*
 199 * Handle hitting a breakpoint.
 200 */
 201void ptrace_break(struct pt_regs *regs)
 202{
 203        force_sig_fault(SIGTRAP, TRAP_BRKPT,
 204                        (void __user *)instruction_pointer(regs));
 205}
 206
 207static int break_trap(struct pt_regs *regs, unsigned int instr)
 208{
 209        ptrace_break(regs);
 210        return 0;
 211}
 212
 213static struct undef_hook arm_break_hook = {
 214        .instr_mask     = 0x0fffffff,
 215        .instr_val      = 0x07f001f0,
 216        .cpsr_mask      = PSR_T_BIT,
 217        .cpsr_val       = 0,
 218        .fn             = break_trap,
 219};
 220
 221static struct undef_hook thumb_break_hook = {
 222        .instr_mask     = 0xffff,
 223        .instr_val      = 0xde01,
 224        .cpsr_mask      = PSR_T_BIT,
 225        .cpsr_val       = PSR_T_BIT,
 226        .fn             = break_trap,
 227};
 228
 229static struct undef_hook thumb2_break_hook = {
 230        .instr_mask     = 0xffffffff,
 231        .instr_val      = 0xf7f0a000,
 232        .cpsr_mask      = PSR_T_BIT,
 233        .cpsr_val       = PSR_T_BIT,
 234        .fn             = break_trap,
 235};
 236
 237static int __init ptrace_break_init(void)
 238{
 239        register_undef_hook(&arm_break_hook);
 240        register_undef_hook(&thumb_break_hook);
 241        register_undef_hook(&thumb2_break_hook);
 242        return 0;
 243}
 244
 245core_initcall(ptrace_break_init);
 246
 247/*
 248 * Read the word at offset "off" into the "struct user".  We
 249 * actually access the pt_regs stored on the kernel stack.
 250 */
 251static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 252                            unsigned long __user *ret)
 253{
 254        unsigned long tmp;
 255
 256        if (off & 3)
 257                return -EIO;
 258
 259        tmp = 0;
 260        if (off == PT_TEXT_ADDR)
 261                tmp = tsk->mm->start_code;
 262        else if (off == PT_DATA_ADDR)
 263                tmp = tsk->mm->start_data;
 264        else if (off == PT_TEXT_END_ADDR)
 265                tmp = tsk->mm->end_code;
 266        else if (off < sizeof(struct pt_regs))
 267                tmp = get_user_reg(tsk, off >> 2);
 268        else if (off >= sizeof(struct user))
 269                return -EIO;
 270
 271        return put_user(tmp, ret);
 272}
 273
 274/*
 275 * Write the word at offset "off" into "struct user".  We
 276 * actually access the pt_regs stored on the kernel stack.
 277 */
 278static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 279                             unsigned long val)
 280{
 281        if (off & 3 || off >= sizeof(struct user))
 282                return -EIO;
 283
 284        if (off >= sizeof(struct pt_regs))
 285                return 0;
 286
 287        return put_user_reg(tsk, off >> 2, val);
 288}
 289
 290#ifdef CONFIG_IWMMXT
 291
 292/*
 293 * Get the child iWMMXt state.
 294 */
 295static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 296{
 297        struct thread_info *thread = task_thread_info(tsk);
 298
 299        if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 300                return -ENODATA;
 301        iwmmxt_task_disable(thread);  /* force it to ram */
 302        return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 303                ? -EFAULT : 0;
 304}
 305
 306/*
 307 * Set the child iWMMXt state.
 308 */
 309static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 310{
 311        struct thread_info *thread = task_thread_info(tsk);
 312
 313        if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 314                return -EACCES;
 315        iwmmxt_task_release(thread);  /* force a reload */
 316        return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 317                ? -EFAULT : 0;
 318}
 319
 320#endif
 321
 322#ifdef CONFIG_CRUNCH
 323/*
 324 * Get the child Crunch state.
 325 */
 326static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 327{
 328        struct thread_info *thread = task_thread_info(tsk);
 329
 330        crunch_task_disable(thread);  /* force it to ram */
 331        return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 332                ? -EFAULT : 0;
 333}
 334
 335/*
 336 * Set the child Crunch state.
 337 */
 338static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 339{
 340        struct thread_info *thread = task_thread_info(tsk);
 341
 342        crunch_task_release(thread);  /* force a reload */
 343        return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 344                ? -EFAULT : 0;
 345}
 346#endif
 347
 348#ifdef CONFIG_HAVE_HW_BREAKPOINT
 349/*
 350 * Convert a virtual register number into an index for a thread_info
 351 * breakpoint array. Breakpoints are identified using positive numbers
 352 * whilst watchpoints are negative. The registers are laid out as pairs
 353 * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 354 * Register 0 is reserved for describing resource information.
 355 */
 356static int ptrace_hbp_num_to_idx(long num)
 357{
 358        if (num < 0)
 359                num = (ARM_MAX_BRP << 1) - num;
 360        return (num - 1) >> 1;
 361}
 362
 363/*
 364 * Returns the virtual register number for the address of the
 365 * breakpoint at index idx.
 366 */
 367static long ptrace_hbp_idx_to_num(int idx)
 368{
 369        long mid = ARM_MAX_BRP << 1;
 370        long num = (idx << 1) + 1;
 371        return num > mid ? mid - num : num;
 372}
 373
 374/*
 375 * Handle hitting a HW-breakpoint.
 376 */
 377static void ptrace_hbptriggered(struct perf_event *bp,
 378                                     struct perf_sample_data *data,
 379                                     struct pt_regs *regs)
 380{
 381        struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 382        long num;
 383        int i;
 384
 385        for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 386                if (current->thread.debug.hbp[i] == bp)
 387                        break;
 388
 389        num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 390
 391        force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 392}
 393
 394/*
 395 * Set ptrace breakpoint pointers to zero for this task.
 396 * This is required in order to prevent child processes from unregistering
 397 * breakpoints held by their parent.
 398 */
 399void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 400{
 401        memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 402}
 403
 404/*
 405 * Unregister breakpoints from this task and reset the pointers in
 406 * the thread_struct.
 407 */
 408void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 409{
 410        int i;
 411        struct thread_struct *t = &tsk->thread;
 412
 413        for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 414                if (t->debug.hbp[i]) {
 415                        unregister_hw_breakpoint(t->debug.hbp[i]);
 416                        t->debug.hbp[i] = NULL;
 417                }
 418        }
 419}
 420
 421static u32 ptrace_get_hbp_resource_info(void)
 422{
 423        u8 num_brps, num_wrps, debug_arch, wp_len;
 424        u32 reg = 0;
 425
 426        num_brps        = hw_breakpoint_slots(TYPE_INST);
 427        num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 428        debug_arch      = arch_get_debug_arch();
 429        wp_len          = arch_get_max_wp_len();
 430
 431        reg             |= debug_arch;
 432        reg             <<= 8;
 433        reg             |= wp_len;
 434        reg             <<= 8;
 435        reg             |= num_wrps;
 436        reg             <<= 8;
 437        reg             |= num_brps;
 438
 439        return reg;
 440}
 441
 442static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 443{
 444        struct perf_event_attr attr;
 445
 446        ptrace_breakpoint_init(&attr);
 447
 448        /* Initialise fields to sane defaults. */
 449        attr.bp_addr    = 0;
 450        attr.bp_len     = HW_BREAKPOINT_LEN_4;
 451        attr.bp_type    = type;
 452        attr.disabled   = 1;
 453
 454        return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 455                                           tsk);
 456}
 457
 458static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 459                             unsigned long  __user *data)
 460{
 461        u32 reg;
 462        int idx, ret = 0;
 463        struct perf_event *bp;
 464        struct arch_hw_breakpoint_ctrl arch_ctrl;
 465
 466        if (num == 0) {
 467                reg = ptrace_get_hbp_resource_info();
 468        } else {
 469                idx = ptrace_hbp_num_to_idx(num);
 470                if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 471                        ret = -EINVAL;
 472                        goto out;
 473                }
 474
 475                bp = tsk->thread.debug.hbp[idx];
 476                if (!bp) {
 477                        reg = 0;
 478                        goto put;
 479                }
 480
 481                arch_ctrl = counter_arch_bp(bp)->ctrl;
 482
 483                /*
 484                 * Fix up the len because we may have adjusted it
 485                 * to compensate for an unaligned address.
 486                 */
 487                while (!(arch_ctrl.len & 0x1))
 488                        arch_ctrl.len >>= 1;
 489
 490                if (num & 0x1)
 491                        reg = bp->attr.bp_addr;
 492                else
 493                        reg = encode_ctrl_reg(arch_ctrl);
 494        }
 495
 496put:
 497        if (put_user(reg, data))
 498                ret = -EFAULT;
 499
 500out:
 501        return ret;
 502}
 503
 504static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 505                             unsigned long __user *data)
 506{
 507        int idx, gen_len, gen_type, implied_type, ret = 0;
 508        u32 user_val;
 509        struct perf_event *bp;
 510        struct arch_hw_breakpoint_ctrl ctrl;
 511        struct perf_event_attr attr;
 512
 513        if (num == 0)
 514                goto out;
 515        else if (num < 0)
 516                implied_type = HW_BREAKPOINT_RW;
 517        else
 518                implied_type = HW_BREAKPOINT_X;
 519
 520        idx = ptrace_hbp_num_to_idx(num);
 521        if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 522                ret = -EINVAL;
 523                goto out;
 524        }
 525
 526        if (get_user(user_val, data)) {
 527                ret = -EFAULT;
 528                goto out;
 529        }
 530
 531        bp = tsk->thread.debug.hbp[idx];
 532        if (!bp) {
 533                bp = ptrace_hbp_create(tsk, implied_type);
 534                if (IS_ERR(bp)) {
 535                        ret = PTR_ERR(bp);
 536                        goto out;
 537                }
 538                tsk->thread.debug.hbp[idx] = bp;
 539        }
 540
 541        attr = bp->attr;
 542
 543        if (num & 0x1) {
 544                /* Address */
 545                attr.bp_addr    = user_val;
 546        } else {
 547                /* Control */
 548                decode_ctrl_reg(user_val, &ctrl);
 549                ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 550                if (ret)
 551                        goto out;
 552
 553                if ((gen_type & implied_type) != gen_type) {
 554                        ret = -EINVAL;
 555                        goto out;
 556                }
 557
 558                attr.bp_len     = gen_len;
 559                attr.bp_type    = gen_type;
 560                attr.disabled   = !ctrl.enabled;
 561        }
 562
 563        ret = modify_user_hw_breakpoint(bp, &attr);
 564out:
 565        return ret;
 566}
 567#endif
 568
 569/* regset get/set implementations */
 570
 571static int gpr_get(struct task_struct *target,
 572                   const struct user_regset *regset,
 573                   unsigned int pos, unsigned int count,
 574                   void *kbuf, void __user *ubuf)
 575{
 576        struct pt_regs *regs = task_pt_regs(target);
 577
 578        return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 579                                   regs,
 580                                   0, sizeof(*regs));
 581}
 582
 583static int gpr_set(struct task_struct *target,
 584                   const struct user_regset *regset,
 585                   unsigned int pos, unsigned int count,
 586                   const void *kbuf, const void __user *ubuf)
 587{
 588        int ret;
 589        struct pt_regs newregs = *task_pt_regs(target);
 590
 591        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 592                                 &newregs,
 593                                 0, sizeof(newregs));
 594        if (ret)
 595                return ret;
 596
 597        if (!valid_user_regs(&newregs))
 598                return -EINVAL;
 599
 600        *task_pt_regs(target) = newregs;
 601        return 0;
 602}
 603
 604static int fpa_get(struct task_struct *target,
 605                   const struct user_regset *regset,
 606                   unsigned int pos, unsigned int count,
 607                   void *kbuf, void __user *ubuf)
 608{
 609        return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 610                                   &task_thread_info(target)->fpstate,
 611                                   0, sizeof(struct user_fp));
 612}
 613
 614static int fpa_set(struct task_struct *target,
 615                   const struct user_regset *regset,
 616                   unsigned int pos, unsigned int count,
 617                   const void *kbuf, const void __user *ubuf)
 618{
 619        struct thread_info *thread = task_thread_info(target);
 620
 621        thread->used_cp[1] = thread->used_cp[2] = 1;
 622
 623        return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 624                &thread->fpstate,
 625                0, sizeof(struct user_fp));
 626}
 627
 628#ifdef CONFIG_VFP
 629/*
 630 * VFP register get/set implementations.
 631 *
 632 * With respect to the kernel, struct user_fp is divided into three chunks:
 633 * 16 or 32 real VFP registers (d0-d15 or d0-31)
 634 *      These are transferred to/from the real registers in the task's
 635 *      vfp_hard_struct.  The number of registers depends on the kernel
 636 *      configuration.
 637 *
 638 * 16 or 0 fake VFP registers (d16-d31 or empty)
 639 *      i.e., the user_vfp structure has space for 32 registers even if
 640 *      the kernel doesn't have them all.
 641 *
 642 *      vfp_get() reads this chunk as zero where applicable
 643 *      vfp_set() ignores this chunk
 644 *
 645 * 1 word for the FPSCR
 646 *
 647 * The bounds-checking logic built into user_regset_copyout and friends
 648 * means that we can make a simple sequence of calls to map the relevant data
 649 * to/from the specified slice of the user regset structure.
 650 */
 651static int vfp_get(struct task_struct *target,
 652                   const struct user_regset *regset,
 653                   unsigned int pos, unsigned int count,
 654                   void *kbuf, void __user *ubuf)
 655{
 656        int ret;
 657        struct thread_info *thread = task_thread_info(target);
 658        struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 659        const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 660        const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 661
 662        vfp_sync_hwstate(thread);
 663
 664        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 665                                  &vfp->fpregs,
 666                                  user_fpregs_offset,
 667                                  user_fpregs_offset + sizeof(vfp->fpregs));
 668        if (ret)
 669                return ret;
 670
 671        ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 672                                       user_fpregs_offset + sizeof(vfp->fpregs),
 673                                       user_fpscr_offset);
 674        if (ret)
 675                return ret;
 676
 677        return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 678                                   &vfp->fpscr,
 679                                   user_fpscr_offset,
 680                                   user_fpscr_offset + sizeof(vfp->fpscr));
 681}
 682
 683/*
 684 * For vfp_set() a read-modify-write is done on the VFP registers,
 685 * in order to avoid writing back a half-modified set of registers on
 686 * failure.
 687 */
 688static int vfp_set(struct task_struct *target,
 689                          const struct user_regset *regset,
 690                          unsigned int pos, unsigned int count,
 691                          const void *kbuf, const void __user *ubuf)
 692{
 693        int ret;
 694        struct thread_info *thread = task_thread_info(target);
 695        struct vfp_hard_struct new_vfp;
 696        const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 697        const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 698
 699        vfp_sync_hwstate(thread);
 700        new_vfp = thread->vfpstate.hard;
 701
 702        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 703                                  &new_vfp.fpregs,
 704                                  user_fpregs_offset,
 705                                  user_fpregs_offset + sizeof(new_vfp.fpregs));
 706        if (ret)
 707                return ret;
 708
 709        ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 710                                user_fpregs_offset + sizeof(new_vfp.fpregs),
 711                                user_fpscr_offset);
 712        if (ret)
 713                return ret;
 714
 715        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 716                                 &new_vfp.fpscr,
 717                                 user_fpscr_offset,
 718                                 user_fpscr_offset + sizeof(new_vfp.fpscr));
 719        if (ret)
 720                return ret;
 721
 722        thread->vfpstate.hard = new_vfp;
 723        vfp_flush_hwstate(thread);
 724
 725        return 0;
 726}
 727#endif /* CONFIG_VFP */
 728
 729enum arm_regset {
 730        REGSET_GPR,
 731        REGSET_FPR,
 732#ifdef CONFIG_VFP
 733        REGSET_VFP,
 734#endif
 735};
 736
 737static const struct user_regset arm_regsets[] = {
 738        [REGSET_GPR] = {
 739                .core_note_type = NT_PRSTATUS,
 740                .n = ELF_NGREG,
 741                .size = sizeof(u32),
 742                .align = sizeof(u32),
 743                .get = gpr_get,
 744                .set = gpr_set
 745        },
 746        [REGSET_FPR] = {
 747                /*
 748                 * For the FPA regs in fpstate, the real fields are a mixture
 749                 * of sizes, so pretend that the registers are word-sized:
 750                 */
 751                .core_note_type = NT_PRFPREG,
 752                .n = sizeof(struct user_fp) / sizeof(u32),
 753                .size = sizeof(u32),
 754                .align = sizeof(u32),
 755                .get = fpa_get,
 756                .set = fpa_set
 757        },
 758#ifdef CONFIG_VFP
 759        [REGSET_VFP] = {
 760                /*
 761                 * Pretend that the VFP regs are word-sized, since the FPSCR is
 762                 * a single word dangling at the end of struct user_vfp:
 763                 */
 764                .core_note_type = NT_ARM_VFP,
 765                .n = ARM_VFPREGS_SIZE / sizeof(u32),
 766                .size = sizeof(u32),
 767                .align = sizeof(u32),
 768                .get = vfp_get,
 769                .set = vfp_set
 770        },
 771#endif /* CONFIG_VFP */
 772};
 773
 774static const struct user_regset_view user_arm_view = {
 775        .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 776        .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 777};
 778
 779const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 780{
 781        return &user_arm_view;
 782}
 783
 784long arch_ptrace(struct task_struct *child, long request,
 785                 unsigned long addr, unsigned long data)
 786{
 787        int ret;
 788        unsigned long __user *datap = (unsigned long __user *) data;
 789
 790        switch (request) {
 791                case PTRACE_PEEKUSR:
 792                        ret = ptrace_read_user(child, addr, datap);
 793                        break;
 794
 795                case PTRACE_POKEUSR:
 796                        ret = ptrace_write_user(child, addr, data);
 797                        break;
 798
 799                case PTRACE_GETREGS:
 800                        ret = copy_regset_to_user(child,
 801                                                  &user_arm_view, REGSET_GPR,
 802                                                  0, sizeof(struct pt_regs),
 803                                                  datap);
 804                        break;
 805
 806                case PTRACE_SETREGS:
 807                        ret = copy_regset_from_user(child,
 808                                                    &user_arm_view, REGSET_GPR,
 809                                                    0, sizeof(struct pt_regs),
 810                                                    datap);
 811                        break;
 812
 813                case PTRACE_GETFPREGS:
 814                        ret = copy_regset_to_user(child,
 815                                                  &user_arm_view, REGSET_FPR,
 816                                                  0, sizeof(union fp_state),
 817                                                  datap);
 818                        break;
 819
 820                case PTRACE_SETFPREGS:
 821                        ret = copy_regset_from_user(child,
 822                                                    &user_arm_view, REGSET_FPR,
 823                                                    0, sizeof(union fp_state),
 824                                                    datap);
 825                        break;
 826
 827#ifdef CONFIG_IWMMXT
 828                case PTRACE_GETWMMXREGS:
 829                        ret = ptrace_getwmmxregs(child, datap);
 830                        break;
 831
 832                case PTRACE_SETWMMXREGS:
 833                        ret = ptrace_setwmmxregs(child, datap);
 834                        break;
 835#endif
 836
 837                case PTRACE_GET_THREAD_AREA:
 838                        ret = put_user(task_thread_info(child)->tp_value[0],
 839                                       datap);
 840                        break;
 841
 842                case PTRACE_SET_SYSCALL:
 843                        task_thread_info(child)->syscall = data;
 844                        ret = 0;
 845                        break;
 846
 847#ifdef CONFIG_CRUNCH
 848                case PTRACE_GETCRUNCHREGS:
 849                        ret = ptrace_getcrunchregs(child, datap);
 850                        break;
 851
 852                case PTRACE_SETCRUNCHREGS:
 853                        ret = ptrace_setcrunchregs(child, datap);
 854                        break;
 855#endif
 856
 857#ifdef CONFIG_VFP
 858                case PTRACE_GETVFPREGS:
 859                        ret = copy_regset_to_user(child,
 860                                                  &user_arm_view, REGSET_VFP,
 861                                                  0, ARM_VFPREGS_SIZE,
 862                                                  datap);
 863                        break;
 864
 865                case PTRACE_SETVFPREGS:
 866                        ret = copy_regset_from_user(child,
 867                                                    &user_arm_view, REGSET_VFP,
 868                                                    0, ARM_VFPREGS_SIZE,
 869                                                    datap);
 870                        break;
 871#endif
 872
 873#ifdef CONFIG_HAVE_HW_BREAKPOINT
 874                case PTRACE_GETHBPREGS:
 875                        ret = ptrace_gethbpregs(child, addr,
 876                                                (unsigned long __user *)data);
 877                        break;
 878                case PTRACE_SETHBPREGS:
 879                        ret = ptrace_sethbpregs(child, addr,
 880                                                (unsigned long __user *)data);
 881                        break;
 882#endif
 883
 884                default:
 885                        ret = ptrace_request(child, request, addr, data);
 886                        break;
 887        }
 888
 889        return ret;
 890}
 891
 892enum ptrace_syscall_dir {
 893        PTRACE_SYSCALL_ENTER = 0,
 894        PTRACE_SYSCALL_EXIT,
 895};
 896
 897static void tracehook_report_syscall(struct pt_regs *regs,
 898                                    enum ptrace_syscall_dir dir)
 899{
 900        unsigned long ip;
 901
 902        /*
 903         * IP is used to denote syscall entry/exit:
 904         * IP = 0 -> entry, =1 -> exit
 905         */
 906        ip = regs->ARM_ip;
 907        regs->ARM_ip = dir;
 908
 909        if (dir == PTRACE_SYSCALL_EXIT)
 910                tracehook_report_syscall_exit(regs, 0);
 911        else if (tracehook_report_syscall_entry(regs))
 912                current_thread_info()->syscall = -1;
 913
 914        regs->ARM_ip = ip;
 915}
 916
 917asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 918{
 919        current_thread_info()->syscall = scno;
 920
 921        if (test_thread_flag(TIF_SYSCALL_TRACE))
 922                tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 923
 924        /* Do seccomp after ptrace; syscall may have changed. */
 925#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 926        if (secure_computing(NULL) == -1)
 927                return -1;
 928#else
 929        /* XXX: remove this once OABI gets fixed */
 930        secure_computing_strict(current_thread_info()->syscall);
 931#endif
 932
 933        /* Tracer or seccomp may have changed syscall. */
 934        scno = current_thread_info()->syscall;
 935
 936        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 937                trace_sys_enter(regs, scno);
 938
 939        audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 940                            regs->ARM_r3);
 941
 942        return scno;
 943}
 944
 945asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 946{
 947        /*
 948         * Audit the syscall before anything else, as a debugger may
 949         * come in and change the current registers.
 950         */
 951        audit_syscall_exit(regs);
 952
 953        /*
 954         * Note that we haven't updated the ->syscall field for the
 955         * current thread. This isn't a problem because it will have
 956         * been set on syscall entry and there hasn't been an opportunity
 957         * for a PTRACE_SET_SYSCALL since then.
 958         */
 959        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 960                trace_sys_exit(regs, regs_return_value(regs));
 961
 962        if (test_thread_flag(TIF_SYSCALL_TRACE))
 963                tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 964}
 965