arch/arm/kernel/ptrace.c

   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/traps.h>
  29
  30 #define CREATE_TRACE_POINTS
  31 #include <trace/events/syscalls.h>
  32
  33 #define REG_PC  15
  34 #define REG_PSR 16
  35 /*
  36  * does not yet catch signals sent when the child dies.
  37  * in exit.c or in signal.c.
  38  */
  39
  40 #if 0
  41 /*
  42  * Breakpoint SWI instruction: SWI &9F0001
  43  */
  44 #define BREAKINST_ARM   0xef9f0001
  45 #define BREAKINST_THUMB 0xdf00          /* fill this in later */
  46 #else
  47 /*
  48  * New breakpoints - use an undefined instruction.  The ARM architecture
  49  * reference manual guarantees that the following instruction space
  50  * will produce an undefined instruction exception on all CPUs:
  51  *
  52  *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
  53  *  Thumb: 1101 1110 xxxx xxxx
  54  */
  55 #define BREAKINST_ARM   0xe7f001f0
  56 #define BREAKINST_THUMB 0xde01
  57 #endif
  58
  59 struct pt_regs_offset {
  60         const char *name;
  61         int offset;
  62 };
  63
  64 #define REG_OFFSET_NAME(r) \
  65         {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
  66 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  67
  68 static const struct pt_regs_offset regoffset_table[] = {
  69         REG_OFFSET_NAME(r0),
  70         REG_OFFSET_NAME(r1),
  71         REG_OFFSET_NAME(r2),
  72         REG_OFFSET_NAME(r3),
  73         REG_OFFSET_NAME(r4),
  74         REG_OFFSET_NAME(r5),
  75         REG_OFFSET_NAME(r6),
  76         REG_OFFSET_NAME(r7),
  77         REG_OFFSET_NAME(r8),
  78         REG_OFFSET_NAME(r9),
  79         REG_OFFSET_NAME(r10),
  80         REG_OFFSET_NAME(fp),
  81         REG_OFFSET_NAME(ip),
  82         REG_OFFSET_NAME(sp),
  83         REG_OFFSET_NAME(lr),
  84         REG_OFFSET_NAME(pc),
  85         REG_OFFSET_NAME(cpsr),
  86         REG_OFFSET_NAME(ORIG_r0),
  87         REG_OFFSET_END,
  88 };
  89
  90 /**
  91  * regs_query_register_offset() - query register offset from its name
  92  * @name:       the name of a register
  93  *
  94  * regs_query_register_offset() returns the offset of a register in struct
  95  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
  96  */
  97 int regs_query_register_offset(const char *name)
  98 {
  99         const struct pt_regs_offset *roff;
 100         for (roff = regoffset_table; roff->name != NULL; roff++)
 101                 if (!strcmp(roff->name, name))
 102                         return roff->offset;
 103         return -EINVAL;
 104 }
 105
 106 /**
 107  * regs_query_register_name() - query register name from its offset
 108  * @offset:     the offset of a register in struct pt_regs.
 109  *
 110  * regs_query_register_name() returns the name of a register from its
 111  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 112  */
 113 const char *regs_query_register_name(unsigned int offset)
 114 {
 115         const struct pt_regs_offset *roff;
 116         for (roff = regoffset_table; roff->name != NULL; roff++)
 117                 if (roff->offset == offset)
 118                         return roff->name;
 119         return NULL;
 120 }
 121
 122 /**
 123  * regs_within_kernel_stack() - check the address in the stack
 124  * @regs:      pt_regs which contains kernel stack pointer.
 125  * @addr:      address which is checked.
 126  *
 127  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 128  * If @addr is within the kernel stack, it returns true. If not, returns false.
 129  */
 130 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 131 {
 132         return ((addr & ~(THREAD_SIZE - 1))  ==
 133                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 134 }
 135
 136 /**
 137  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 138  * @regs:       pt_regs which contains kernel stack pointer.
 139  * @n:          stack entry number.
 140  *
 141  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 142  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 143  * this returns 0.
 144  */
 145 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 146 {
 147         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 148         addr += n;
 149         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 150                 return *addr;
 151         else
 152                 return 0;
 153 }
 154
 155 /*
 156  * this routine will get a word off of the processes privileged stack.
 157  * the offset is how far from the base addr as stored in the THREAD.
 158  * this routine assumes that all the privileged stacks are in our
 159  * data space.
 160  */
 161 static inline long get_user_reg(struct task_struct *task, int offset)
 162 {
 163         return task_pt_regs(task)->uregs[offset];
 164 }
 165
 166 /*
 167  * this routine will put a word on the processes privileged stack.
 168  * the offset is how far from the base addr as stored in the THREAD.
 169  * this routine assumes that all the privileged stacks are in our
 170  * data space.
 171  */
 172 static inline int
 173 put_user_reg(struct task_struct *task, int offset, long data)
 174 {
 175         struct pt_regs newregs, *regs = task_pt_regs(task);
 176         int ret = -EINVAL;
 177
 178         newregs = *regs;
 179         newregs.uregs[offset] = data;
 180
 181         if (valid_user_regs(&newregs)) {
 182                 regs->uregs[offset] = data;
 183                 ret = 0;
 184         }
 185
 186         return ret;
 187 }
 188
 189 /*
 190  * Called by kernel/ptrace.c when detaching..
 191  */
 192 void ptrace_disable(struct task_struct *child)
 193 {
 194         /* Nothing to do. */
 195 }
 196
 197 /*
 198  * Handle hitting a breakpoint.
 199  */
 200 void ptrace_break(struct pt_regs *regs)
 201 {
 202         force_sig_fault(SIGTRAP, TRAP_BRKPT,
 203                         (void __user *)instruction_pointer(regs));
 204 }
 205
 206 static int break_trap(struct pt_regs *regs, unsigned int instr)
 207 {
 208         ptrace_break(regs);
 209         return 0;
 210 }
 211
 212 static struct undef_hook arm_break_hook = {
 213         .instr_mask     = 0x0fffffff,
 214         .instr_val      = 0x07f001f0,
 215         .cpsr_mask      = PSR_T_BIT,
 216         .cpsr_val       = 0,
 217         .fn             = break_trap,
 218 };
 219
 220 static struct undef_hook thumb_break_hook = {
 221         .instr_mask     = 0xffffffff,
 222         .instr_val      = 0x0000de01,
 223         .cpsr_mask      = PSR_T_BIT,
 224         .cpsr_val       = PSR_T_BIT,
 225         .fn             = break_trap,
 226 };
 227
 228 static struct undef_hook thumb2_break_hook = {
 229         .instr_mask     = 0xffffffff,
 230         .instr_val      = 0xf7f0a000,
 231         .cpsr_mask      = PSR_T_BIT,
 232         .cpsr_val       = PSR_T_BIT,
 233         .fn             = break_trap,
 234 };
 235
 236 static int __init ptrace_break_init(void)
 237 {
 238         register_undef_hook(&arm_break_hook);
 239         register_undef_hook(&thumb_break_hook);
 240         register_undef_hook(&thumb2_break_hook);
 241         return 0;
 242 }
 243
 244 core_initcall(ptrace_break_init);
 245
 246 /*
 247  * Read the word at offset "off" into the "struct user".  We
 248  * actually access the pt_regs stored on the kernel stack.
 249  */
 250 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 251                             unsigned long __user *ret)
 252 {
 253         unsigned long tmp;
 254
 255         if (off & 3)
 256                 return -EIO;
 257
 258         tmp = 0;
 259         if (off == PT_TEXT_ADDR)
 260                 tmp = tsk->mm->start_code;
 261         else if (off == PT_DATA_ADDR)
 262                 tmp = tsk->mm->start_data;
 263         else if (off == PT_TEXT_END_ADDR)
 264                 tmp = tsk->mm->end_code;
 265         else if (off < sizeof(struct pt_regs))
 266                 tmp = get_user_reg(tsk, off >> 2);
 267         else if (off >= sizeof(struct user))
 268                 return -EIO;
 269
 270         return put_user(tmp, ret);
 271 }
 272
 273 /*
 274  * Write the word at offset "off" into "struct user".  We
 275  * actually access the pt_regs stored on the kernel stack.
 276  */
 277 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 278                              unsigned long val)
 279 {
 280         if (off & 3 || off >= sizeof(struct user))
 281                 return -EIO;
 282
 283         if (off >= sizeof(struct pt_regs))
 284                 return 0;
 285
 286         return put_user_reg(tsk, off >> 2, val);
 287 }
 288
 289 #ifdef CONFIG_IWMMXT
 290
 291 /*
 292  * Get the child iWMMXt state.
 293  */
 294 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 295 {
 296         struct thread_info *thread = task_thread_info(tsk);
 297
 298         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 299                 return -ENODATA;
 300         iwmmxt_task_disable(thread);  /* force it to ram */
 301         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 302                 ? -EFAULT : 0;
 303 }
 304
 305 /*
 306  * Set the child iWMMXt state.
 307  */
 308 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 309 {
 310         struct thread_info *thread = task_thread_info(tsk);
 311
 312         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 313                 return -EACCES;
 314         iwmmxt_task_release(thread);  /* force a reload */
 315         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 316                 ? -EFAULT : 0;
 317 }
 318
 319 #endif
 320
 321 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 322 /*
 323  * Convert a virtual register number into an index for a thread_info
 324  * breakpoint array. Breakpoints are identified using positive numbers
 325  * whilst watchpoints are negative. The registers are laid out as pairs
 326  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 327  * Register 0 is reserved for describing resource information.
 328  */
 329 static int ptrace_hbp_num_to_idx(long num)
 330 {
 331         if (num < 0)
 332                 num = (ARM_MAX_BRP << 1) - num;
 333         return (num - 1) >> 1;
 334 }
 335
 336 /*
 337  * Returns the virtual register number for the address of the
 338  * breakpoint at index idx.
 339  */
 340 static long ptrace_hbp_idx_to_num(int idx)
 341 {
 342         long mid = ARM_MAX_BRP << 1;
 343         long num = (idx << 1) + 1;
 344         return num > mid ? mid - num : num;
 345 }
 346
 347 /*
 348  * Handle hitting a HW-breakpoint.
 349  */
 350 static void ptrace_hbptriggered(struct perf_event *bp,
 351                                      struct perf_sample_data *data,
 352                                      struct pt_regs *regs)
 353 {
 354         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 355         long num;
 356         int i;
 357
 358         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 359                 if (current->thread.debug.hbp[i] == bp)
 360                         break;
 361
 362         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 363
 364         force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 365 }
 366
 367 /*
 368  * Set ptrace breakpoint pointers to zero for this task.
 369  * This is required in order to prevent child processes from unregistering
 370  * breakpoints held by their parent.
 371  */
 372 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 373 {
 374         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 375 }
 376
 377 /*
 378  * Unregister breakpoints from this task and reset the pointers in
 379  * the thread_struct.
 380  */
 381 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 382 {
 383         int i;
 384         struct thread_struct *t = &tsk->thread;
 385
 386         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 387                 if (t->debug.hbp[i]) {
 388                         unregister_hw_breakpoint(t->debug.hbp[i]);
 389                         t->debug.hbp[i] = NULL;
 390                 }
 391         }
 392 }
 393
 394 static u32 ptrace_get_hbp_resource_info(void)
 395 {
 396         u8 num_brps, num_wrps, debug_arch, wp_len;
 397         u32 reg = 0;
 398
 399         num_brps        = hw_breakpoint_slots(TYPE_INST);
 400         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 401         debug_arch      = arch_get_debug_arch();
 402         wp_len          = arch_get_max_wp_len();
 403
 404         reg             |= debug_arch;
 405         reg             <<= 8;
 406         reg             |= wp_len;
 407         reg             <<= 8;
 408         reg             |= num_wrps;
 409         reg             <<= 8;
 410         reg             |= num_brps;
 411
 412         return reg;
 413 }
 414
 415 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 416 {
 417         struct perf_event_attr attr;
 418
 419         ptrace_breakpoint_init(&attr);
 420
 421         /* Initialise fields to sane defaults. */
 422         attr.bp_addr    = 0;
 423         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 424         attr.bp_type    = type;
 425         attr.disabled   = 1;
 426
 427         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 428                                            tsk);
 429 }
 430
 431 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 432                              unsigned long  __user *data)
 433 {
 434         u32 reg;
 435         int idx, ret = 0;
 436         struct perf_event *bp;
 437         struct arch_hw_breakpoint_ctrl arch_ctrl;
 438
 439         if (num == 0) {
 440                 reg = ptrace_get_hbp_resource_info();
 441         } else {
 442                 idx = ptrace_hbp_num_to_idx(num);
 443                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 444                         ret = -EINVAL;
 445                         goto out;
 446                 }
 447
 448                 bp = tsk->thread.debug.hbp[idx];
 449                 if (!bp) {
 450                         reg = 0;
 451                         goto put;
 452                 }
 453
 454                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 455
 456                 /*
 457                  * Fix up the len because we may have adjusted it
 458                  * to compensate for an unaligned address.
 459                  */
 460                 while (!(arch_ctrl.len & 0x1))
 461                         arch_ctrl.len >>= 1;
 462
 463                 if (num & 0x1)
 464                         reg = bp->attr.bp_addr;
 465                 else
 466                         reg = encode_ctrl_reg(arch_ctrl);
 467         }
 468
 469 put:
 470         if (put_user(reg, data))
 471                 ret = -EFAULT;
 472
 473 out:
 474         return ret;
 475 }
 476
 477 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 478                              unsigned long __user *data)
 479 {
 480         int idx, gen_len, gen_type, implied_type, ret = 0;
 481         u32 user_val;
 482         struct perf_event *bp;
 483         struct arch_hw_breakpoint_ctrl ctrl;
 484         struct perf_event_attr attr;
 485
 486         if (num == 0)
 487                 goto out;
 488         else if (num < 0)
 489                 implied_type = HW_BREAKPOINT_RW;
 490         else
 491                 implied_type = HW_BREAKPOINT_X;
 492
 493         idx = ptrace_hbp_num_to_idx(num);
 494         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 495                 ret = -EINVAL;
 496                 goto out;
 497         }
 498
 499         if (get_user(user_val, data)) {
 500                 ret = -EFAULT;
 501                 goto out;
 502         }
 503
 504         bp = tsk->thread.debug.hbp[idx];
 505         if (!bp) {
 506                 bp = ptrace_hbp_create(tsk, implied_type);
 507                 if (IS_ERR(bp)) {
 508                         ret = PTR_ERR(bp);
 509                         goto out;
 510                 }
 511                 tsk->thread.debug.hbp[idx] = bp;
 512         }
 513
 514         attr = bp->attr;
 515
 516         if (num & 0x1) {
 517                 /* Address */
 518                 attr.bp_addr    = user_val;
 519         } else {
 520                 /* Control */
 521                 decode_ctrl_reg(user_val, &ctrl);
 522                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 523                 if (ret)
 524                         goto out;
 525
 526                 if ((gen_type & implied_type) != gen_type) {
 527                         ret = -EINVAL;
 528                         goto out;
 529                 }
 530
 531                 attr.bp_len     = gen_len;
 532                 attr.bp_type    = gen_type;
 533                 attr.disabled   = !ctrl.enabled;
 534         }
 535
 536         ret = modify_user_hw_breakpoint(bp, &attr);
 537 out:
 538         return ret;
 539 }
 540 #endif
 541
 542 /* regset get/set implementations */
 543
 544 static int gpr_get(struct task_struct *target,
 545                    const struct user_regset *regset,
 546                    struct membuf to)
 547 {
 548         return membuf_write(&to, task_pt_regs(target), sizeof(struct pt_regs));
 549 }
 550
 551 static int gpr_set(struct task_struct *target,
 552                    const struct user_regset *regset,
 553                    unsigned int pos, unsigned int count,
 554                    const void *kbuf, const void __user *ubuf)
 555 {
 556         int ret;
 557         struct pt_regs newregs = *task_pt_regs(target);
 558
 559         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 560                                  &newregs,
 561                                  0, sizeof(newregs));
 562         if (ret)
 563                 return ret;
 564
 565         if (!valid_user_regs(&newregs))
 566                 return -EINVAL;
 567
 568         *task_pt_regs(target) = newregs;
 569         return 0;
 570 }
 571
 572 static int fpa_get(struct task_struct *target,
 573                    const struct user_regset *regset,
 574                    struct membuf to)
 575 {
 576         return membuf_write(&to, &task_thread_info(target)->fpstate,
 577                                  sizeof(struct user_fp));
 578 }
 579
 580 static int fpa_set(struct task_struct *target,
 581                    const struct user_regset *regset,
 582                    unsigned int pos, unsigned int count,
 583                    const void *kbuf, const void __user *ubuf)
 584 {
 585         struct thread_info *thread = task_thread_info(target);
 586
 587         thread->used_cp[1] = thread->used_cp[2] = 1;
 588
 589         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 590                 &thread->fpstate,
 591                 0, sizeof(struct user_fp));
 592 }
 593
 594 #ifdef CONFIG_VFP
 595 /*
 596  * VFP register get/set implementations.
 597  *
 598  * With respect to the kernel, struct user_fp is divided into three chunks:
 599  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 600  *      These are transferred to/from the real registers in the task's
 601  *      vfp_hard_struct.  The number of registers depends on the kernel
 602  *      configuration.
 603  *
 604  * 16 or 0 fake VFP registers (d16-d31 or empty)
 605  *      i.e., the user_vfp structure has space for 32 registers even if
 606  *      the kernel doesn't have them all.
 607  *
 608  *      vfp_get() reads this chunk as zero where applicable
 609  *      vfp_set() ignores this chunk
 610  *
 611  * 1 word for the FPSCR
 612  */
 613 static int vfp_get(struct task_struct *target,
 614                    const struct user_regset *regset,
 615                    struct membuf to)
 616 {
 617         struct thread_info *thread = task_thread_info(target);
 618         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 619         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 620
 621         vfp_sync_hwstate(thread);
 622
 623         membuf_write(&to, vfp->fpregs, sizeof(vfp->fpregs));
 624         membuf_zero(&to, user_fpscr_offset - sizeof(vfp->fpregs));
 625         return membuf_store(&to, vfp->fpscr);
 626 }
 627
 628 /*
 629  * For vfp_set() a read-modify-write is done on the VFP registers,
 630  * in order to avoid writing back a half-modified set of registers on
 631  * failure.
 632  */
 633 static int vfp_set(struct task_struct *target,
 634                           const struct user_regset *regset,
 635                           unsigned int pos, unsigned int count,
 636                           const void *kbuf, const void __user *ubuf)
 637 {
 638         int ret;
 639         struct thread_info *thread = task_thread_info(target);
 640         struct vfp_hard_struct new_vfp;
 641         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 642         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 643
 644         vfp_sync_hwstate(thread);
 645         new_vfp = thread->vfpstate.hard;
 646
 647         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 648                                   &new_vfp.fpregs,
 649                                   user_fpregs_offset,
 650                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 651         if (ret)
 652                 return ret;
 653
 654         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 655                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 656                                 user_fpscr_offset);
 657         if (ret)
 658                 return ret;
 659
 660         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 661                                  &new_vfp.fpscr,
 662                                  user_fpscr_offset,
 663                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 664         if (ret)
 665                 return ret;
 666
 667         thread->vfpstate.hard = new_vfp;
 668         vfp_flush_hwstate(thread);
 669
 670         return 0;
 671 }
 672 #endif /* CONFIG_VFP */
 673
 674 enum arm_regset {
 675         REGSET_GPR,
 676         REGSET_FPR,
 677 #ifdef CONFIG_VFP
 678         REGSET_VFP,
 679 #endif
 680 };
 681
 682 static const struct user_regset arm_regsets[] = {
 683         [REGSET_GPR] = {
 684                 .core_note_type = NT_PRSTATUS,
 685                 .n = ELF_NGREG,
 686                 .size = sizeof(u32),
 687                 .align = sizeof(u32),
 688                 .regset_get = gpr_get,
 689                 .set = gpr_set
 690         },
 691         [REGSET_FPR] = {
 692                 /*
 693                  * For the FPA regs in fpstate, the real fields are a mixture
 694                  * of sizes, so pretend that the registers are word-sized:
 695                  */
 696                 .core_note_type = NT_PRFPREG,
 697                 .n = sizeof(struct user_fp) / sizeof(u32),
 698                 .size = sizeof(u32),
 699                 .align = sizeof(u32),
 700                 .regset_get = fpa_get,
 701                 .set = fpa_set
 702         },
 703 #ifdef CONFIG_VFP
 704         [REGSET_VFP] = {
 705                 /*
 706                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 707                  * a single word dangling at the end of struct user_vfp:
 708                  */
 709                 .core_note_type = NT_ARM_VFP,
 710                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 711                 .size = sizeof(u32),
 712                 .align = sizeof(u32),
 713                 .regset_get = vfp_get,
 714                 .set = vfp_set
 715         },
 716 #endif /* CONFIG_VFP */
 717 };
 718
 719 static const struct user_regset_view user_arm_view = {
 720         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 721         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 722 };
 723
 724 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 725 {
 726         return &user_arm_view;
 727 }
 728
 729 long arch_ptrace(struct task_struct *child, long request,
 730                  unsigned long addr, unsigned long data)
 731 {
 732         int ret;
 733         unsigned long __user *datap = (unsigned long __user *) data;
 734
 735         switch (request) {
 736                 case PTRACE_PEEKUSR:
 737                         ret = ptrace_read_user(child, addr, datap);
 738                         break;
 739
 740                 case PTRACE_POKEUSR:
 741                         ret = ptrace_write_user(child, addr, data);
 742                         break;
 743
 744                 case PTRACE_GETREGS:
 745                         ret = copy_regset_to_user(child,
 746                                                   &user_arm_view, REGSET_GPR,
 747                                                   0, sizeof(struct pt_regs),
 748                                                   datap);
 749                         break;
 750
 751                 case PTRACE_SETREGS:
 752                         ret = copy_regset_from_user(child,
 753                                                     &user_arm_view, REGSET_GPR,
 754                                                     0, sizeof(struct pt_regs),
 755                                                     datap);
 756                         break;
 757
 758                 case PTRACE_GETFPREGS:
 759                         ret = copy_regset_to_user(child,
 760                                                   &user_arm_view, REGSET_FPR,
 761                                                   0, sizeof(union fp_state),
 762                                                   datap);
 763                         break;
 764
 765                 case PTRACE_SETFPREGS:
 766                         ret = copy_regset_from_user(child,
 767                                                     &user_arm_view, REGSET_FPR,
 768                                                     0, sizeof(union fp_state),
 769                                                     datap);
 770                         break;
 771
 772 #ifdef CONFIG_IWMMXT
 773                 case PTRACE_GETWMMXREGS:
 774                         ret = ptrace_getwmmxregs(child, datap);
 775                         break;
 776
 777                 case PTRACE_SETWMMXREGS:
 778                         ret = ptrace_setwmmxregs(child, datap);
 779                         break;
 780 #endif
 781
 782                 case PTRACE_GET_THREAD_AREA:
 783                         ret = put_user(task_thread_info(child)->tp_value[0],
 784                                        datap);
 785                         break;
 786
 787                 case PTRACE_SET_SYSCALL:
 788                         task_thread_info(child)->syscall = data;
 789                         ret = 0;
 790                         break;
 791
 792 #ifdef CONFIG_VFP
 793                 case PTRACE_GETVFPREGS:
 794                         ret = copy_regset_to_user(child,
 795                                                   &user_arm_view, REGSET_VFP,
 796                                                   0, ARM_VFPREGS_SIZE,
 797                                                   datap);
 798                         break;
 799
 800                 case PTRACE_SETVFPREGS:
 801                         ret = copy_regset_from_user(child,
 802                                                     &user_arm_view, REGSET_VFP,
 803                                                     0, ARM_VFPREGS_SIZE,
 804                                                     datap);
 805                         break;
 806 #endif
 807
 808 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 809                 case PTRACE_GETHBPREGS:
 810                         ret = ptrace_gethbpregs(child, addr,
 811                                                 (unsigned long __user *)data);
 812                         break;
 813                 case PTRACE_SETHBPREGS:
 814                         ret = ptrace_sethbpregs(child, addr,
 815                                                 (unsigned long __user *)data);
 816                         break;
 817 #endif
 818
 819                 default:
 820                         ret = ptrace_request(child, request, addr, data);
 821                         break;
 822         }
 823
 824         return ret;
 825 }
 826
 827 enum ptrace_syscall_dir {
 828         PTRACE_SYSCALL_ENTER = 0,
 829         PTRACE_SYSCALL_EXIT,
 830 };
 831
 832 static void tracehook_report_syscall(struct pt_regs *regs,
 833                                     enum ptrace_syscall_dir dir)
 834 {
 835         unsigned long ip;
 836
 837         /*
 838          * IP is used to denote syscall entry/exit:
 839          * IP = 0 -> entry, =1 -> exit
 840          */
 841         ip = regs->ARM_ip;
 842         regs->ARM_ip = dir;
 843
 844         if (dir == PTRACE_SYSCALL_EXIT)
 845                 tracehook_report_syscall_exit(regs, 0);
 846         else if (tracehook_report_syscall_entry(regs))
 847                 current_thread_info()->syscall = -1;
 848
 849         regs->ARM_ip = ip;
 850 }
 851
 852 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 853 {
 854         current_thread_info()->syscall = scno;
 855
 856         if (test_thread_flag(TIF_SYSCALL_TRACE))
 857                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 858
 859         /* Do seccomp after ptrace; syscall may have changed. */
 860 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 861         if (secure_computing() == -1)
 862                 return -1;
 863 #else
 864         /* XXX: remove this once OABI gets fixed */
 865         secure_computing_strict(current_thread_info()->syscall);
 866 #endif
 867
 868         /* Tracer or seccomp may have changed syscall. */
 869         scno = current_thread_info()->syscall;
 870
 871         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 872                 trace_sys_enter(regs, scno);
 873
 874         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 875                             regs->ARM_r3);
 876
 877         return scno;
 878 }
 879
 880 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 881 {
 882         /*
 883          * Audit the syscall before anything else, as a debugger may
 884          * come in and change the current registers.
 885          */
 886         audit_syscall_exit(regs);
 887
 888         /*
 889          * Note that we haven't updated the ->syscall field for the
 890          * current thread. This isn't a problem because it will have
 891          * been set on syscall entry and there hasn't been an opportunity
 892          * for a PTRACE_SET_SYSCALL since then.
 893          */
 894         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 895                 trace_sys_exit(regs, regs_return_value(regs));
 896
 897         if (test_thread_flag(TIF_SYSCALL_TRACE))
 898                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 899 }