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/unistd.h>
  26
  27 #include <asm/syscall.h>
  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         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 588                 &thread->fpstate,
 589                 0, sizeof(struct user_fp));
 590 }
 591
 592 #ifdef CONFIG_VFP
 593 /*
 594  * VFP register get/set implementations.
 595  *
 596  * With respect to the kernel, struct user_fp is divided into three chunks:
 597  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 598  *      These are transferred to/from the real registers in the task's
 599  *      vfp_hard_struct.  The number of registers depends on the kernel
 600  *      configuration.
 601  *
 602  * 16 or 0 fake VFP registers (d16-d31 or empty)
 603  *      i.e., the user_vfp structure has space for 32 registers even if
 604  *      the kernel doesn't have them all.
 605  *
 606  *      vfp_get() reads this chunk as zero where applicable
 607  *      vfp_set() ignores this chunk
 608  *
 609  * 1 word for the FPSCR
 610  */
 611 static int vfp_get(struct task_struct *target,
 612                    const struct user_regset *regset,
 613                    struct membuf to)
 614 {
 615         struct thread_info *thread = task_thread_info(target);
 616         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 617         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 618
 619         vfp_sync_hwstate(thread);
 620
 621         membuf_write(&to, vfp->fpregs, sizeof(vfp->fpregs));
 622         membuf_zero(&to, user_fpscr_offset - sizeof(vfp->fpregs));
 623         return membuf_store(&to, vfp->fpscr);
 624 }
 625
 626 /*
 627  * For vfp_set() a read-modify-write is done on the VFP registers,
 628  * in order to avoid writing back a half-modified set of registers on
 629  * failure.
 630  */
 631 static int vfp_set(struct task_struct *target,
 632                           const struct user_regset *regset,
 633                           unsigned int pos, unsigned int count,
 634                           const void *kbuf, const void __user *ubuf)
 635 {
 636         int ret;
 637         struct thread_info *thread = task_thread_info(target);
 638         struct vfp_hard_struct new_vfp;
 639         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 640         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 641
 642         vfp_sync_hwstate(thread);
 643         new_vfp = thread->vfpstate.hard;
 644
 645         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 646                                   &new_vfp.fpregs,
 647                                   user_fpregs_offset,
 648                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 649         if (ret)
 650                 return ret;
 651
 652         user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 653                                   user_fpregs_offset + sizeof(new_vfp.fpregs),
 654                                   user_fpscr_offset);
 655
 656         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 657                                  &new_vfp.fpscr,
 658                                  user_fpscr_offset,
 659                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 660         if (ret)
 661                 return ret;
 662
 663         thread->vfpstate.hard = new_vfp;
 664         vfp_flush_hwstate(thread);
 665
 666         return 0;
 667 }
 668 #endif /* CONFIG_VFP */
 669
 670 enum arm_regset {
 671         REGSET_GPR,
 672         REGSET_FPR,
 673 #ifdef CONFIG_VFP
 674         REGSET_VFP,
 675 #endif
 676 };
 677
 678 static const struct user_regset arm_regsets[] = {
 679         [REGSET_GPR] = {
 680                 .core_note_type = NT_PRSTATUS,
 681                 .n = ELF_NGREG,
 682                 .size = sizeof(u32),
 683                 .align = sizeof(u32),
 684                 .regset_get = gpr_get,
 685                 .set = gpr_set
 686         },
 687         [REGSET_FPR] = {
 688                 /*
 689                  * For the FPA regs in fpstate, the real fields are a mixture
 690                  * of sizes, so pretend that the registers are word-sized:
 691                  */
 692                 .core_note_type = NT_PRFPREG,
 693                 .n = sizeof(struct user_fp) / sizeof(u32),
 694                 .size = sizeof(u32),
 695                 .align = sizeof(u32),
 696                 .regset_get = fpa_get,
 697                 .set = fpa_set
 698         },
 699 #ifdef CONFIG_VFP
 700         [REGSET_VFP] = {
 701                 /*
 702                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 703                  * a single word dangling at the end of struct user_vfp:
 704                  */
 705                 .core_note_type = NT_ARM_VFP,
 706                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 707                 .size = sizeof(u32),
 708                 .align = sizeof(u32),
 709                 .regset_get = vfp_get,
 710                 .set = vfp_set
 711         },
 712 #endif /* CONFIG_VFP */
 713 };
 714
 715 static const struct user_regset_view user_arm_view = {
 716         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 717         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 718 };
 719
 720 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 721 {
 722         return &user_arm_view;
 723 }
 724
 725 long arch_ptrace(struct task_struct *child, long request,
 726                  unsigned long addr, unsigned long data)
 727 {
 728         int ret;
 729         unsigned long __user *datap = (unsigned long __user *) data;
 730
 731         switch (request) {
 732                 case PTRACE_PEEKUSR:
 733                         ret = ptrace_read_user(child, addr, datap);
 734                         break;
 735
 736                 case PTRACE_POKEUSR:
 737                         ret = ptrace_write_user(child, addr, data);
 738                         break;
 739
 740                 case PTRACE_GETREGS:
 741                         ret = copy_regset_to_user(child,
 742                                                   &user_arm_view, REGSET_GPR,
 743                                                   0, sizeof(struct pt_regs),
 744                                                   datap);
 745                         break;
 746
 747                 case PTRACE_SETREGS:
 748                         ret = copy_regset_from_user(child,
 749                                                     &user_arm_view, REGSET_GPR,
 750                                                     0, sizeof(struct pt_regs),
 751                                                     datap);
 752                         break;
 753
 754                 case PTRACE_GETFPREGS:
 755                         ret = copy_regset_to_user(child,
 756                                                   &user_arm_view, REGSET_FPR,
 757                                                   0, sizeof(union fp_state),
 758                                                   datap);
 759                         break;
 760
 761                 case PTRACE_SETFPREGS:
 762                         ret = copy_regset_from_user(child,
 763                                                     &user_arm_view, REGSET_FPR,
 764                                                     0, sizeof(union fp_state),
 765                                                     datap);
 766                         break;
 767
 768 #ifdef CONFIG_IWMMXT
 769                 case PTRACE_GETWMMXREGS:
 770                         ret = ptrace_getwmmxregs(child, datap);
 771                         break;
 772
 773                 case PTRACE_SETWMMXREGS:
 774                         ret = ptrace_setwmmxregs(child, datap);
 775                         break;
 776 #endif
 777
 778                 case PTRACE_GET_THREAD_AREA:
 779                         ret = put_user(task_thread_info(child)->tp_value[0],
 780                                        datap);
 781                         break;
 782
 783                 case PTRACE_SET_SYSCALL:
 784                         if (data != -1)
 785                                 data &= __NR_SYSCALL_MASK;
 786                         task_thread_info(child)->abi_syscall = data;
 787                         ret = 0;
 788                         break;
 789
 790 #ifdef CONFIG_VFP
 791                 case PTRACE_GETVFPREGS:
 792                         ret = copy_regset_to_user(child,
 793                                                   &user_arm_view, REGSET_VFP,
 794                                                   0, ARM_VFPREGS_SIZE,
 795                                                   datap);
 796                         break;
 797
 798                 case PTRACE_SETVFPREGS:
 799                         ret = copy_regset_from_user(child,
 800                                                     &user_arm_view, REGSET_VFP,
 801                                                     0, ARM_VFPREGS_SIZE,
 802                                                     datap);
 803                         break;
 804 #endif
 805
 806 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 807                 case PTRACE_GETHBPREGS:
 808                         ret = ptrace_gethbpregs(child, addr,
 809                                                 (unsigned long __user *)data);
 810                         break;
 811                 case PTRACE_SETHBPREGS:
 812                         ret = ptrace_sethbpregs(child, addr,
 813                                                 (unsigned long __user *)data);
 814                         break;
 815 #endif
 816
 817                 default:
 818                         ret = ptrace_request(child, request, addr, data);
 819                         break;
 820         }
 821
 822         return ret;
 823 }
 824
 825 enum ptrace_syscall_dir {
 826         PTRACE_SYSCALL_ENTER = 0,
 827         PTRACE_SYSCALL_EXIT,
 828 };
 829
 830 static void report_syscall(struct pt_regs *regs, enum ptrace_syscall_dir dir)
 831 {
 832         unsigned long ip;
 833
 834         /*
 835          * IP is used to denote syscall entry/exit:
 836          * IP = 0 -> entry, =1 -> exit
 837          */
 838         ip = regs->ARM_ip;
 839         regs->ARM_ip = dir;
 840
 841         if (dir == PTRACE_SYSCALL_EXIT)
 842                 ptrace_report_syscall_exit(regs, 0);
 843         else if (ptrace_report_syscall_entry(regs))
 844                 current_thread_info()->abi_syscall = -1;
 845
 846         regs->ARM_ip = ip;
 847 }
 848
 849 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
 850 {
 851         int scno;
 852
 853         if (test_thread_flag(TIF_SYSCALL_TRACE))
 854                 report_syscall(regs, PTRACE_SYSCALL_ENTER);
 855
 856         /* Do seccomp after ptrace; syscall may have changed. */
 857 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 858         if (secure_computing() == -1)
 859                 return -1;
 860 #else
 861         /* XXX: remove this once OABI gets fixed */
 862         secure_computing_strict(syscall_get_nr(current, regs));
 863 #endif
 864
 865         /* Tracer or seccomp may have changed syscall. */
 866         scno = syscall_get_nr(current, regs);
 867
 868         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 869                 trace_sys_enter(regs, scno);
 870
 871         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 872                             regs->ARM_r3);
 873
 874         return scno;
 875 }
 876
 877 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 878 {
 879         /*
 880          * Audit the syscall before anything else, as a debugger may
 881          * come in and change the current registers.
 882          */
 883         audit_syscall_exit(regs);
 884
 885         /*
 886          * Note that we haven't updated the ->syscall field for the
 887          * current thread. This isn't a problem because it will have
 888          * been set on syscall entry and there hasn't been an opportunity
 889          * for a PTRACE_SET_SYSCALL since then.
 890          */
 891         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 892                 trace_sys_exit(regs, regs_return_value(regs));
 893
 894         if (test_thread_flag(TIF_SYSCALL_TRACE))
 895                 report_syscall(regs, PTRACE_SYSCALL_EXIT);
 896 }