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/syscall.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
  60 struct 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
  69 static 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  */
  98 int 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  */
 114 const 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  */
 131 bool 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  */
 146 unsigned 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  */
 162 static 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  */
 173 static inline int
 174 put_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  */
 193 void ptrace_disable(struct task_struct *child)
 194 {
 195         /* Nothing to do. */
 196 }
 197
 198 /*
 199  * Handle hitting a breakpoint.
 200  */
 201 void ptrace_break(struct pt_regs *regs)
 202 {
 203         force_sig_fault(SIGTRAP, TRAP_BRKPT,
 204                         (void __user *)instruction_pointer(regs));
 205 }
 206
 207 static int break_trap(struct pt_regs *regs, unsigned int instr)
 208 {
 209         ptrace_break(regs);
 210         return 0;
 211 }
 212
 213 static 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
 221 static struct undef_hook thumb_break_hook = {
 222         .instr_mask     = 0xffffffff,
 223         .instr_val      = 0x0000de01,
 224         .cpsr_mask      = PSR_T_BIT,
 225         .cpsr_val       = PSR_T_BIT,
 226         .fn             = break_trap,
 227 };
 228
 229 static 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
 237 static 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
 245 core_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  */
 251 static 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  */
 278 static 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  */
 295 static 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  */
 309 static 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_HAVE_HW_BREAKPOINT
 323 /*
 324  * Convert a virtual register number into an index for a thread_info
 325  * breakpoint array. Breakpoints are identified using positive numbers
 326  * whilst watchpoints are negative. The registers are laid out as pairs
 327  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 328  * Register 0 is reserved for describing resource information.
 329  */
 330 static int ptrace_hbp_num_to_idx(long num)
 331 {
 332         if (num < 0)
 333                 num = (ARM_MAX_BRP << 1) - num;
 334         return (num - 1) >> 1;
 335 }
 336
 337 /*
 338  * Returns the virtual register number for the address of the
 339  * breakpoint at index idx.
 340  */
 341 static long ptrace_hbp_idx_to_num(int idx)
 342 {
 343         long mid = ARM_MAX_BRP << 1;
 344         long num = (idx << 1) + 1;
 345         return num > mid ? mid - num : num;
 346 }
 347
 348 /*
 349  * Handle hitting a HW-breakpoint.
 350  */
 351 static void ptrace_hbptriggered(struct perf_event *bp,
 352                                      struct perf_sample_data *data,
 353                                      struct pt_regs *regs)
 354 {
 355         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 356         long num;
 357         int i;
 358
 359         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 360                 if (current->thread.debug.hbp[i] == bp)
 361                         break;
 362
 363         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 364
 365         force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 366 }
 367
 368 /*
 369  * Set ptrace breakpoint pointers to zero for this task.
 370  * This is required in order to prevent child processes from unregistering
 371  * breakpoints held by their parent.
 372  */
 373 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 374 {
 375         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 376 }
 377
 378 /*
 379  * Unregister breakpoints from this task and reset the pointers in
 380  * the thread_struct.
 381  */
 382 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 383 {
 384         int i;
 385         struct thread_struct *t = &tsk->thread;
 386
 387         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 388                 if (t->debug.hbp[i]) {
 389                         unregister_hw_breakpoint(t->debug.hbp[i]);
 390                         t->debug.hbp[i] = NULL;
 391                 }
 392         }
 393 }
 394
 395 static u32 ptrace_get_hbp_resource_info(void)
 396 {
 397         u8 num_brps, num_wrps, debug_arch, wp_len;
 398         u32 reg = 0;
 399
 400         num_brps        = hw_breakpoint_slots(TYPE_INST);
 401         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 402         debug_arch      = arch_get_debug_arch();
 403         wp_len          = arch_get_max_wp_len();
 404
 405         reg             |= debug_arch;
 406         reg             <<= 8;
 407         reg             |= wp_len;
 408         reg             <<= 8;
 409         reg             |= num_wrps;
 410         reg             <<= 8;
 411         reg             |= num_brps;
 412
 413         return reg;
 414 }
 415
 416 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 417 {
 418         struct perf_event_attr attr;
 419
 420         ptrace_breakpoint_init(&attr);
 421
 422         /* Initialise fields to sane defaults. */
 423         attr.bp_addr    = 0;
 424         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 425         attr.bp_type    = type;
 426         attr.disabled   = 1;
 427
 428         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 429                                            tsk);
 430 }
 431
 432 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 433                              unsigned long  __user *data)
 434 {
 435         u32 reg;
 436         int idx, ret = 0;
 437         struct perf_event *bp;
 438         struct arch_hw_breakpoint_ctrl arch_ctrl;
 439
 440         if (num == 0) {
 441                 reg = ptrace_get_hbp_resource_info();
 442         } else {
 443                 idx = ptrace_hbp_num_to_idx(num);
 444                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 445                         ret = -EINVAL;
 446                         goto out;
 447                 }
 448
 449                 bp = tsk->thread.debug.hbp[idx];
 450                 if (!bp) {
 451                         reg = 0;
 452                         goto put;
 453                 }
 454
 455                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 456
 457                 /*
 458                  * Fix up the len because we may have adjusted it
 459                  * to compensate for an unaligned address.
 460                  */
 461                 while (!(arch_ctrl.len & 0x1))
 462                         arch_ctrl.len >>= 1;
 463
 464                 if (num & 0x1)
 465                         reg = bp->attr.bp_addr;
 466                 else
 467                         reg = encode_ctrl_reg(arch_ctrl);
 468         }
 469
 470 put:
 471         if (put_user(reg, data))
 472                 ret = -EFAULT;
 473
 474 out:
 475         return ret;
 476 }
 477
 478 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 479                              unsigned long __user *data)
 480 {
 481         int idx, gen_len, gen_type, implied_type, ret = 0;
 482         u32 user_val;
 483         struct perf_event *bp;
 484         struct arch_hw_breakpoint_ctrl ctrl;
 485         struct perf_event_attr attr;
 486
 487         if (num == 0)
 488                 goto out;
 489         else if (num < 0)
 490                 implied_type = HW_BREAKPOINT_RW;
 491         else
 492                 implied_type = HW_BREAKPOINT_X;
 493
 494         idx = ptrace_hbp_num_to_idx(num);
 495         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 496                 ret = -EINVAL;
 497                 goto out;
 498         }
 499
 500         if (get_user(user_val, data)) {
 501                 ret = -EFAULT;
 502                 goto out;
 503         }
 504
 505         bp = tsk->thread.debug.hbp[idx];
 506         if (!bp) {
 507                 bp = ptrace_hbp_create(tsk, implied_type);
 508                 if (IS_ERR(bp)) {
 509                         ret = PTR_ERR(bp);
 510                         goto out;
 511                 }
 512                 tsk->thread.debug.hbp[idx] = bp;
 513         }
 514
 515         attr = bp->attr;
 516
 517         if (num & 0x1) {
 518                 /* Address */
 519                 attr.bp_addr    = user_val;
 520         } else {
 521                 /* Control */
 522                 decode_ctrl_reg(user_val, &ctrl);
 523                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 524                 if (ret)
 525                         goto out;
 526
 527                 if ((gen_type & implied_type) != gen_type) {
 528                         ret = -EINVAL;
 529                         goto out;
 530                 }
 531
 532                 attr.bp_len     = gen_len;
 533                 attr.bp_type    = gen_type;
 534                 attr.disabled   = !ctrl.enabled;
 535         }
 536
 537         ret = modify_user_hw_breakpoint(bp, &attr);
 538 out:
 539         return ret;
 540 }
 541 #endif
 542
 543 /* regset get/set implementations */
 544
 545 static int gpr_get(struct task_struct *target,
 546                    const struct user_regset *regset,
 547                    struct membuf to)
 548 {
 549         return membuf_write(&to, task_pt_regs(target), sizeof(struct pt_regs));
 550 }
 551
 552 static int gpr_set(struct task_struct *target,
 553                    const struct user_regset *regset,
 554                    unsigned int pos, unsigned int count,
 555                    const void *kbuf, const void __user *ubuf)
 556 {
 557         int ret;
 558         struct pt_regs newregs = *task_pt_regs(target);
 559
 560         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 561                                  &newregs,
 562                                  0, sizeof(newregs));
 563         if (ret)
 564                 return ret;
 565
 566         if (!valid_user_regs(&newregs))
 567                 return -EINVAL;
 568
 569         *task_pt_regs(target) = newregs;
 570         return 0;
 571 }
 572
 573 static int fpa_get(struct task_struct *target,
 574                    const struct user_regset *regset,
 575                    struct membuf to)
 576 {
 577         return membuf_write(&to, &task_thread_info(target)->fpstate,
 578                                  sizeof(struct user_fp));
 579 }
 580
 581 static int fpa_set(struct task_struct *target,
 582                    const struct user_regset *regset,
 583                    unsigned int pos, unsigned int count,
 584                    const void *kbuf, const void __user *ubuf)
 585 {
 586         struct thread_info *thread = task_thread_info(target);
 587
 588         thread->used_cp[1] = thread->used_cp[2] = 1;
 589
 590         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 591                 &thread->fpstate,
 592                 0, sizeof(struct user_fp));
 593 }
 594
 595 #ifdef CONFIG_VFP
 596 /*
 597  * VFP register get/set implementations.
 598  *
 599  * With respect to the kernel, struct user_fp is divided into three chunks:
 600  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 601  *      These are transferred to/from the real registers in the task's
 602  *      vfp_hard_struct.  The number of registers depends on the kernel
 603  *      configuration.
 604  *
 605  * 16 or 0 fake VFP registers (d16-d31 or empty)
 606  *      i.e., the user_vfp structure has space for 32 registers even if
 607  *      the kernel doesn't have them all.
 608  *
 609  *      vfp_get() reads this chunk as zero where applicable
 610  *      vfp_set() ignores this chunk
 611  *
 612  * 1 word for the FPSCR
 613  */
 614 static int vfp_get(struct task_struct *target,
 615                    const struct user_regset *regset,
 616                    struct membuf to)
 617 {
 618         struct thread_info *thread = task_thread_info(target);
 619         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 620         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 621
 622         vfp_sync_hwstate(thread);
 623
 624         membuf_write(&to, vfp->fpregs, sizeof(vfp->fpregs));
 625         membuf_zero(&to, user_fpscr_offset - sizeof(vfp->fpregs));
 626         return membuf_store(&to, vfp->fpscr);
 627 }
 628
 629 /*
 630  * For vfp_set() a read-modify-write is done on the VFP registers,
 631  * in order to avoid writing back a half-modified set of registers on
 632  * failure.
 633  */
 634 static int vfp_set(struct task_struct *target,
 635                           const struct user_regset *regset,
 636                           unsigned int pos, unsigned int count,
 637                           const void *kbuf, const void __user *ubuf)
 638 {
 639         int ret;
 640         struct thread_info *thread = task_thread_info(target);
 641         struct vfp_hard_struct new_vfp;
 642         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 643         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 644
 645         vfp_sync_hwstate(thread);
 646         new_vfp = thread->vfpstate.hard;
 647
 648         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 649                                   &new_vfp.fpregs,
 650                                   user_fpregs_offset,
 651                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 652         if (ret)
 653                 return ret;
 654
 655         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 656                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 657                                 user_fpscr_offset);
 658         if (ret)
 659                 return ret;
 660
 661         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 662                                  &new_vfp.fpscr,
 663                                  user_fpscr_offset,
 664                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 665         if (ret)
 666                 return ret;
 667
 668         thread->vfpstate.hard = new_vfp;
 669         vfp_flush_hwstate(thread);
 670
 671         return 0;
 672 }
 673 #endif /* CONFIG_VFP */
 674
 675 enum arm_regset {
 676         REGSET_GPR,
 677         REGSET_FPR,
 678 #ifdef CONFIG_VFP
 679         REGSET_VFP,
 680 #endif
 681 };
 682
 683 static const struct user_regset arm_regsets[] = {
 684         [REGSET_GPR] = {
 685                 .core_note_type = NT_PRSTATUS,
 686                 .n = ELF_NGREG,
 687                 .size = sizeof(u32),
 688                 .align = sizeof(u32),
 689                 .regset_get = gpr_get,
 690                 .set = gpr_set
 691         },
 692         [REGSET_FPR] = {
 693                 /*
 694                  * For the FPA regs in fpstate, the real fields are a mixture
 695                  * of sizes, so pretend that the registers are word-sized:
 696                  */
 697                 .core_note_type = NT_PRFPREG,
 698                 .n = sizeof(struct user_fp) / sizeof(u32),
 699                 .size = sizeof(u32),
 700                 .align = sizeof(u32),
 701                 .regset_get = fpa_get,
 702                 .set = fpa_set
 703         },
 704 #ifdef CONFIG_VFP
 705         [REGSET_VFP] = {
 706                 /*
 707                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 708                  * a single word dangling at the end of struct user_vfp:
 709                  */
 710                 .core_note_type = NT_ARM_VFP,
 711                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 712                 .size = sizeof(u32),
 713                 .align = sizeof(u32),
 714                 .regset_get = vfp_get,
 715                 .set = vfp_set
 716         },
 717 #endif /* CONFIG_VFP */
 718 };
 719
 720 static const struct user_regset_view user_arm_view = {
 721         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 722         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 723 };
 724
 725 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 726 {
 727         return &user_arm_view;
 728 }
 729
 730 long arch_ptrace(struct task_struct *child, long request,
 731                  unsigned long addr, unsigned long data)
 732 {
 733         int ret;
 734         unsigned long __user *datap = (unsigned long __user *) data;
 735
 736         switch (request) {
 737                 case PTRACE_PEEKUSR:
 738                         ret = ptrace_read_user(child, addr, datap);
 739                         break;
 740
 741                 case PTRACE_POKEUSR:
 742                         ret = ptrace_write_user(child, addr, data);
 743                         break;
 744
 745                 case PTRACE_GETREGS:
 746                         ret = copy_regset_to_user(child,
 747                                                   &user_arm_view, REGSET_GPR,
 748                                                   0, sizeof(struct pt_regs),
 749                                                   datap);
 750                         break;
 751
 752                 case PTRACE_SETREGS:
 753                         ret = copy_regset_from_user(child,
 754                                                     &user_arm_view, REGSET_GPR,
 755                                                     0, sizeof(struct pt_regs),
 756                                                     datap);
 757                         break;
 758
 759                 case PTRACE_GETFPREGS:
 760                         ret = copy_regset_to_user(child,
 761                                                   &user_arm_view, REGSET_FPR,
 762                                                   0, sizeof(union fp_state),
 763                                                   datap);
 764                         break;
 765
 766                 case PTRACE_SETFPREGS:
 767                         ret = copy_regset_from_user(child,
 768                                                     &user_arm_view, REGSET_FPR,
 769                                                     0, sizeof(union fp_state),
 770                                                     datap);
 771                         break;
 772
 773 #ifdef CONFIG_IWMMXT
 774                 case PTRACE_GETWMMXREGS:
 775                         ret = ptrace_getwmmxregs(child, datap);
 776                         break;
 777
 778                 case PTRACE_SETWMMXREGS:
 779                         ret = ptrace_setwmmxregs(child, datap);
 780                         break;
 781 #endif
 782
 783                 case PTRACE_GET_THREAD_AREA:
 784                         ret = put_user(task_thread_info(child)->tp_value[0],
 785                                        datap);
 786                         break;
 787
 788                 case PTRACE_SET_SYSCALL:
 789                         task_thread_info(child)->abi_syscall = data &
 790                                                         __NR_SYSCALL_MASK;
 791                         ret = 0;
 792                         break;
 793
 794 #ifdef CONFIG_VFP
 795                 case PTRACE_GETVFPREGS:
 796                         ret = copy_regset_to_user(child,
 797                                                   &user_arm_view, REGSET_VFP,
 798                                                   0, ARM_VFPREGS_SIZE,
 799                                                   datap);
 800                         break;
 801
 802                 case PTRACE_SETVFPREGS:
 803                         ret = copy_regset_from_user(child,
 804                                                     &user_arm_view, REGSET_VFP,
 805                                                     0, ARM_VFPREGS_SIZE,
 806                                                     datap);
 807                         break;
 808 #endif
 809
 810 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 811                 case PTRACE_GETHBPREGS:
 812                         ret = ptrace_gethbpregs(child, addr,
 813                                                 (unsigned long __user *)data);
 814                         break;
 815                 case PTRACE_SETHBPREGS:
 816                         ret = ptrace_sethbpregs(child, addr,
 817                                                 (unsigned long __user *)data);
 818                         break;
 819 #endif
 820
 821                 default:
 822                         ret = ptrace_request(child, request, addr, data);
 823                         break;
 824         }
 825
 826         return ret;
 827 }
 828
 829 enum ptrace_syscall_dir {
 830         PTRACE_SYSCALL_ENTER = 0,
 831         PTRACE_SYSCALL_EXIT,
 832 };
 833
 834 static void tracehook_report_syscall(struct pt_regs *regs,
 835                                     enum ptrace_syscall_dir dir)
 836 {
 837         unsigned long ip;
 838
 839         /*
 840          * IP is used to denote syscall entry/exit:
 841          * IP = 0 -> entry, =1 -> exit
 842          */
 843         ip = regs->ARM_ip;
 844         regs->ARM_ip = dir;
 845
 846         if (dir == PTRACE_SYSCALL_EXIT)
 847                 tracehook_report_syscall_exit(regs, 0);
 848         else if (tracehook_report_syscall_entry(regs))
 849                 current_thread_info()->abi_syscall = -1;
 850
 851         regs->ARM_ip = ip;
 852 }
 853
 854 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
 855 {
 856         int scno;
 857
 858         if (test_thread_flag(TIF_SYSCALL_TRACE))
 859                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 860
 861         /* Do seccomp after ptrace; syscall may have changed. */
 862 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 863         if (secure_computing() == -1)
 864                 return -1;
 865 #else
 866         /* XXX: remove this once OABI gets fixed */
 867         secure_computing_strict(syscall_get_nr(current, regs));
 868 #endif
 869
 870         /* Tracer or seccomp may have changed syscall. */
 871         scno = syscall_get_nr(current, regs);
 872
 873         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 874                 trace_sys_enter(regs, scno);
 875
 876         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 877                             regs->ARM_r3);
 878
 879         return scno;
 880 }
 881
 882 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 883 {
 884         /*
 885          * Audit the syscall before anything else, as a debugger may
 886          * come in and change the current registers.
 887          */
 888         audit_syscall_exit(regs);
 889
 890         /*
 891          * Note that we haven't updated the ->syscall field for the
 892          * current thread. This isn't a problem because it will have
 893          * been set on syscall entry and there hasn't been an opportunity
 894          * for a PTRACE_SET_SYSCALL since then.
 895          */
 896         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 897                 trace_sys_exit(regs, regs_return_value(regs));
 898
 899         if (test_thread_flag(TIF_SYSCALL_TRACE))
 900                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 901 }