arch/arm/kernel/ptrace.c

   1 /*
   2  *  linux/arch/arm/kernel/ptrace.c
   3  *
   4  *  By Ross Biro 1/23/92
   5  * edited by Linus Torvalds
   6  * ARM modifications Copyright (C) 2000 Russell King
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/elf.h>
  16 #include <linux/smp.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/user.h>
  19 #include <linux/security.h>
  20 #include <linux/init.h>
  21 #include <linux/signal.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/perf_event.h>
  24 #include <linux/hw_breakpoint.h>
  25 #include <linux/regset.h>
  26 #include <linux/audit.h>
  27
  28 #include <asm/pgtable.h>
  29 #include <asm/traps.h>
  30
  31 #define REG_PC  15
  32 #define REG_PSR 16
  33 /*
  34  * does not yet catch signals sent when the child dies.
  35  * in exit.c or in signal.c.
  36  */
  37
  38 #if 0
  39 /*
  40  * Breakpoint SWI instruction: SWI &9F0001
  41  */
  42 #define BREAKINST_ARM   0xef9f0001
  43 #define BREAKINST_THUMB 0xdf00          /* fill this in later */
  44 #else
  45 /*
  46  * New breakpoints - use an undefined instruction.  The ARM architecture
  47  * reference manual guarantees that the following instruction space
  48  * will produce an undefined instruction exception on all CPUs:
  49  *
  50  *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
  51  *  Thumb: 1101 1110 xxxx xxxx
  52  */
  53 #define BREAKINST_ARM   0xe7f001f0
  54 #define BREAKINST_THUMB 0xde01
  55 #endif
  56
  57 struct pt_regs_offset {
  58         const char *name;
  59         int offset;
  60 };
  61
  62 #define REG_OFFSET_NAME(r) \
  63         {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
  64 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  65
  66 static const struct pt_regs_offset regoffset_table[] = {
  67         REG_OFFSET_NAME(r0),
  68         REG_OFFSET_NAME(r1),
  69         REG_OFFSET_NAME(r2),
  70         REG_OFFSET_NAME(r3),
  71         REG_OFFSET_NAME(r4),
  72         REG_OFFSET_NAME(r5),
  73         REG_OFFSET_NAME(r6),
  74         REG_OFFSET_NAME(r7),
  75         REG_OFFSET_NAME(r8),
  76         REG_OFFSET_NAME(r9),
  77         REG_OFFSET_NAME(r10),
  78         REG_OFFSET_NAME(fp),
  79         REG_OFFSET_NAME(ip),
  80         REG_OFFSET_NAME(sp),
  81         REG_OFFSET_NAME(lr),
  82         REG_OFFSET_NAME(pc),
  83         REG_OFFSET_NAME(cpsr),
  84         REG_OFFSET_NAME(ORIG_r0),
  85         REG_OFFSET_END,
  86 };
  87
  88 /**
  89  * regs_query_register_offset() - query register offset from its name
  90  * @name:       the name of a register
  91  *
  92  * regs_query_register_offset() returns the offset of a register in struct
  93  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
  94  */
  95 int regs_query_register_offset(const char *name)
  96 {
  97         const struct pt_regs_offset *roff;
  98         for (roff = regoffset_table; roff->name != NULL; roff++)
  99                 if (!strcmp(roff->name, name))
 100                         return roff->offset;
 101         return -EINVAL;
 102 }
 103
 104 /**
 105  * regs_query_register_name() - query register name from its offset
 106  * @offset:     the offset of a register in struct pt_regs.
 107  *
 108  * regs_query_register_name() returns the name of a register from its
 109  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 110  */
 111 const char *regs_query_register_name(unsigned int offset)
 112 {
 113         const struct pt_regs_offset *roff;
 114         for (roff = regoffset_table; roff->name != NULL; roff++)
 115                 if (roff->offset == offset)
 116                         return roff->name;
 117         return NULL;
 118 }
 119
 120 /**
 121  * regs_within_kernel_stack() - check the address in the stack
 122  * @regs:      pt_regs which contains kernel stack pointer.
 123  * @addr:      address which is checked.
 124  *
 125  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 126  * If @addr is within the kernel stack, it returns true. If not, returns false.
 127  */
 128 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 129 {
 130         return ((addr & ~(THREAD_SIZE - 1))  ==
 131                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 132 }
 133
 134 /**
 135  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 136  * @regs:       pt_regs which contains kernel stack pointer.
 137  * @n:          stack entry number.
 138  *
 139  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 140  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 141  * this returns 0.
 142  */
 143 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 144 {
 145         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 146         addr += n;
 147         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 148                 return *addr;
 149         else
 150                 return 0;
 151 }
 152
 153 /*
 154  * this routine will get a word off of the processes privileged stack.
 155  * the offset is how far from the base addr as stored in the THREAD.
 156  * this routine assumes that all the privileged stacks are in our
 157  * data space.
 158  */
 159 static inline long get_user_reg(struct task_struct *task, int offset)
 160 {
 161         return task_pt_regs(task)->uregs[offset];
 162 }
 163
 164 /*
 165  * this routine will put a word on the processes privileged stack.
 166  * the offset is how far from the base addr as stored in the THREAD.
 167  * this routine assumes that all the privileged stacks are in our
 168  * data space.
 169  */
 170 static inline int
 171 put_user_reg(struct task_struct *task, int offset, long data)
 172 {
 173         struct pt_regs newregs, *regs = task_pt_regs(task);
 174         int ret = -EINVAL;
 175
 176         newregs = *regs;
 177         newregs.uregs[offset] = data;
 178
 179         if (valid_user_regs(&newregs)) {
 180                 regs->uregs[offset] = data;
 181                 ret = 0;
 182         }
 183
 184         return ret;
 185 }
 186
 187 /*
 188  * Called by kernel/ptrace.c when detaching..
 189  */
 190 void ptrace_disable(struct task_struct *child)
 191 {
 192         /* Nothing to do. */
 193 }
 194
 195 /*
 196  * Handle hitting a breakpoint.
 197  */
 198 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
 199 {
 200         siginfo_t info;
 201
 202         info.si_signo = SIGTRAP;
 203         info.si_errno = 0;
 204         info.si_code  = TRAP_BRKPT;
 205         info.si_addr  = (void __user *)instruction_pointer(regs);
 206
 207         force_sig_info(SIGTRAP, &info, tsk);
 208 }
 209
 210 static int break_trap(struct pt_regs *regs, unsigned int instr)
 211 {
 212         ptrace_break(current, regs);
 213         return 0;
 214 }
 215
 216 static struct undef_hook arm_break_hook = {
 217         .instr_mask     = 0x0fffffff,
 218         .instr_val      = 0x07f001f0,
 219         .cpsr_mask      = PSR_T_BIT,
 220         .cpsr_val       = 0,
 221         .fn             = break_trap,
 222 };
 223
 224 static struct undef_hook thumb_break_hook = {
 225         .instr_mask     = 0xffff,
 226         .instr_val      = 0xde01,
 227         .cpsr_mask      = PSR_T_BIT,
 228         .cpsr_val       = PSR_T_BIT,
 229         .fn             = break_trap,
 230 };
 231
 232 static struct undef_hook thumb2_break_hook = {
 233         .instr_mask     = 0xffffffff,
 234         .instr_val      = 0xf7f0a000,
 235         .cpsr_mask      = PSR_T_BIT,
 236         .cpsr_val       = PSR_T_BIT,
 237         .fn             = break_trap,
 238 };
 239
 240 static int __init ptrace_break_init(void)
 241 {
 242         register_undef_hook(&arm_break_hook);
 243         register_undef_hook(&thumb_break_hook);
 244         register_undef_hook(&thumb2_break_hook);
 245         return 0;
 246 }
 247
 248 core_initcall(ptrace_break_init);
 249
 250 /*
 251  * Read the word at offset "off" into the "struct user".  We
 252  * actually access the pt_regs stored on the kernel stack.
 253  */
 254 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 255                             unsigned long __user *ret)
 256 {
 257         unsigned long tmp;
 258
 259         if (off & 3)
 260                 return -EIO;
 261
 262         tmp = 0;
 263         if (off == PT_TEXT_ADDR)
 264                 tmp = tsk->mm->start_code;
 265         else if (off == PT_DATA_ADDR)
 266                 tmp = tsk->mm->start_data;
 267         else if (off == PT_TEXT_END_ADDR)
 268                 tmp = tsk->mm->end_code;
 269         else if (off < sizeof(struct pt_regs))
 270                 tmp = get_user_reg(tsk, off >> 2);
 271         else if (off >= sizeof(struct user))
 272                 return -EIO;
 273
 274         return put_user(tmp, ret);
 275 }
 276
 277 /*
 278  * Write the word at offset "off" into "struct user".  We
 279  * actually access the pt_regs stored on the kernel stack.
 280  */
 281 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 282                              unsigned long val)
 283 {
 284         if (off & 3 || off >= sizeof(struct user))
 285                 return -EIO;
 286
 287         if (off >= sizeof(struct pt_regs))
 288                 return 0;
 289
 290         return put_user_reg(tsk, off >> 2, val);
 291 }
 292
 293 #ifdef CONFIG_IWMMXT
 294
 295 /*
 296  * Get the child iWMMXt state.
 297  */
 298 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 299 {
 300         struct thread_info *thread = task_thread_info(tsk);
 301
 302         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 303                 return -ENODATA;
 304         iwmmxt_task_disable(thread);  /* force it to ram */
 305         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 306                 ? -EFAULT : 0;
 307 }
 308
 309 /*
 310  * Set the child iWMMXt state.
 311  */
 312 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 313 {
 314         struct thread_info *thread = task_thread_info(tsk);
 315
 316         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 317                 return -EACCES;
 318         iwmmxt_task_release(thread);  /* force a reload */
 319         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 320                 ? -EFAULT : 0;
 321 }
 322
 323 #endif
 324
 325 #ifdef CONFIG_CRUNCH
 326 /*
 327  * Get the child Crunch state.
 328  */
 329 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 330 {
 331         struct thread_info *thread = task_thread_info(tsk);
 332
 333         crunch_task_disable(thread);  /* force it to ram */
 334         return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 335                 ? -EFAULT : 0;
 336 }
 337
 338 /*
 339  * Set the child Crunch state.
 340  */
 341 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 342 {
 343         struct thread_info *thread = task_thread_info(tsk);
 344
 345         crunch_task_release(thread);  /* force a reload */
 346         return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 347                 ? -EFAULT : 0;
 348 }
 349 #endif
 350
 351 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 352 /*
 353  * Convert a virtual register number into an index for a thread_info
 354  * breakpoint array. Breakpoints are identified using positive numbers
 355  * whilst watchpoints are negative. The registers are laid out as pairs
 356  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 357  * Register 0 is reserved for describing resource information.
 358  */
 359 static int ptrace_hbp_num_to_idx(long num)
 360 {
 361         if (num < 0)
 362                 num = (ARM_MAX_BRP << 1) - num;
 363         return (num - 1) >> 1;
 364 }
 365
 366 /*
 367  * Returns the virtual register number for the address of the
 368  * breakpoint at index idx.
 369  */
 370 static long ptrace_hbp_idx_to_num(int idx)
 371 {
 372         long mid = ARM_MAX_BRP << 1;
 373         long num = (idx << 1) + 1;
 374         return num > mid ? mid - num : num;
 375 }
 376
 377 /*
 378  * Handle hitting a HW-breakpoint.
 379  */
 380 static void ptrace_hbptriggered(struct perf_event *bp,
 381                                      struct perf_sample_data *data,
 382                                      struct pt_regs *regs)
 383 {
 384         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 385         long num;
 386         int i;
 387         siginfo_t info;
 388
 389         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 390                 if (current->thread.debug.hbp[i] == bp)
 391                         break;
 392
 393         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 394
 395         info.si_signo   = SIGTRAP;
 396         info.si_errno   = (int)num;
 397         info.si_code    = TRAP_HWBKPT;
 398         info.si_addr    = (void __user *)(bkpt->trigger);
 399
 400         force_sig_info(SIGTRAP, &info, current);
 401 }
 402
 403 /*
 404  * Set ptrace breakpoint pointers to zero for this task.
 405  * This is required in order to prevent child processes from unregistering
 406  * breakpoints held by their parent.
 407  */
 408 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 409 {
 410         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 411 }
 412
 413 /*
 414  * Unregister breakpoints from this task and reset the pointers in
 415  * the thread_struct.
 416  */
 417 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 418 {
 419         int i;
 420         struct thread_struct *t = &tsk->thread;
 421
 422         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 423                 if (t->debug.hbp[i]) {
 424                         unregister_hw_breakpoint(t->debug.hbp[i]);
 425                         t->debug.hbp[i] = NULL;
 426                 }
 427         }
 428 }
 429
 430 static u32 ptrace_get_hbp_resource_info(void)
 431 {
 432         u8 num_brps, num_wrps, debug_arch, wp_len;
 433         u32 reg = 0;
 434
 435         num_brps        = hw_breakpoint_slots(TYPE_INST);
 436         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 437         debug_arch      = arch_get_debug_arch();
 438         wp_len          = arch_get_max_wp_len();
 439
 440         reg             |= debug_arch;
 441         reg             <<= 8;
 442         reg             |= wp_len;
 443         reg             <<= 8;
 444         reg             |= num_wrps;
 445         reg             <<= 8;
 446         reg             |= num_brps;
 447
 448         return reg;
 449 }
 450
 451 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 452 {
 453         struct perf_event_attr attr;
 454
 455         ptrace_breakpoint_init(&attr);
 456
 457         /* Initialise fields to sane defaults. */
 458         attr.bp_addr    = 0;
 459         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 460         attr.bp_type    = type;
 461         attr.disabled   = 1;
 462
 463         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 464                                            tsk);
 465 }
 466
 467 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 468                              unsigned long  __user *data)
 469 {
 470         u32 reg;
 471         int idx, ret = 0;
 472         struct perf_event *bp;
 473         struct arch_hw_breakpoint_ctrl arch_ctrl;
 474
 475         if (num == 0) {
 476                 reg = ptrace_get_hbp_resource_info();
 477         } else {
 478                 idx = ptrace_hbp_num_to_idx(num);
 479                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 480                         ret = -EINVAL;
 481                         goto out;
 482                 }
 483
 484                 bp = tsk->thread.debug.hbp[idx];
 485                 if (!bp) {
 486                         reg = 0;
 487                         goto put;
 488                 }
 489
 490                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 491
 492                 /*
 493                  * Fix up the len because we may have adjusted it
 494                  * to compensate for an unaligned address.
 495                  */
 496                 while (!(arch_ctrl.len & 0x1))
 497                         arch_ctrl.len >>= 1;
 498
 499                 if (num & 0x1)
 500                         reg = bp->attr.bp_addr;
 501                 else
 502                         reg = encode_ctrl_reg(arch_ctrl);
 503         }
 504
 505 put:
 506         if (put_user(reg, data))
 507                 ret = -EFAULT;
 508
 509 out:
 510         return ret;
 511 }
 512
 513 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 514                              unsigned long __user *data)
 515 {
 516         int idx, gen_len, gen_type, implied_type, ret = 0;
 517         u32 user_val;
 518         struct perf_event *bp;
 519         struct arch_hw_breakpoint_ctrl ctrl;
 520         struct perf_event_attr attr;
 521
 522         if (num == 0)
 523                 goto out;
 524         else if (num < 0)
 525                 implied_type = HW_BREAKPOINT_RW;
 526         else
 527                 implied_type = HW_BREAKPOINT_X;
 528
 529         idx = ptrace_hbp_num_to_idx(num);
 530         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 531                 ret = -EINVAL;
 532                 goto out;
 533         }
 534
 535         if (get_user(user_val, data)) {
 536                 ret = -EFAULT;
 537                 goto out;
 538         }
 539
 540         bp = tsk->thread.debug.hbp[idx];
 541         if (!bp) {
 542                 bp = ptrace_hbp_create(tsk, implied_type);
 543                 if (IS_ERR(bp)) {
 544                         ret = PTR_ERR(bp);
 545                         goto out;
 546                 }
 547                 tsk->thread.debug.hbp[idx] = bp;
 548         }
 549
 550         attr = bp->attr;
 551
 552         if (num & 0x1) {
 553                 /* Address */
 554                 attr.bp_addr    = user_val;
 555         } else {
 556                 /* Control */
 557                 decode_ctrl_reg(user_val, &ctrl);
 558                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 559                 if (ret)
 560                         goto out;
 561
 562                 if ((gen_type & implied_type) != gen_type) {
 563                         ret = -EINVAL;
 564                         goto out;
 565                 }
 566
 567                 attr.bp_len     = gen_len;
 568                 attr.bp_type    = gen_type;
 569                 attr.disabled   = !ctrl.enabled;
 570         }
 571
 572         ret = modify_user_hw_breakpoint(bp, &attr);
 573 out:
 574         return ret;
 575 }
 576 #endif
 577
 578 /* regset get/set implementations */
 579
 580 static int gpr_get(struct task_struct *target,
 581                    const struct user_regset *regset,
 582                    unsigned int pos, unsigned int count,
 583                    void *kbuf, void __user *ubuf)
 584 {
 585         struct pt_regs *regs = task_pt_regs(target);
 586
 587         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 588                                    regs,
 589                                    0, sizeof(*regs));
 590 }
 591
 592 static int gpr_set(struct task_struct *target,
 593                    const struct user_regset *regset,
 594                    unsigned int pos, unsigned int count,
 595                    const void *kbuf, const void __user *ubuf)
 596 {
 597         int ret;
 598         struct pt_regs newregs;
 599
 600         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 601                                  &newregs,
 602                                  0, sizeof(newregs));
 603         if (ret)
 604                 return ret;
 605
 606         if (!valid_user_regs(&newregs))
 607                 return -EINVAL;
 608
 609         *task_pt_regs(target) = newregs;
 610         return 0;
 611 }
 612
 613 static int fpa_get(struct task_struct *target,
 614                    const struct user_regset *regset,
 615                    unsigned int pos, unsigned int count,
 616                    void *kbuf, void __user *ubuf)
 617 {
 618         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 619                                    &task_thread_info(target)->fpstate,
 620                                    0, sizeof(struct user_fp));
 621 }
 622
 623 static int fpa_set(struct task_struct *target,
 624                    const struct user_regset *regset,
 625                    unsigned int pos, unsigned int count,
 626                    const void *kbuf, const void __user *ubuf)
 627 {
 628         struct thread_info *thread = task_thread_info(target);
 629
 630         thread->used_cp[1] = thread->used_cp[2] = 1;
 631
 632         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 633                 &thread->fpstate,
 634                 0, sizeof(struct user_fp));
 635 }
 636
 637 #ifdef CONFIG_VFP
 638 /*
 639  * VFP register get/set implementations.
 640  *
 641  * With respect to the kernel, struct user_fp is divided into three chunks:
 642  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 643  *      These are transferred to/from the real registers in the task's
 644  *      vfp_hard_struct.  The number of registers depends on the kernel
 645  *      configuration.
 646  *
 647  * 16 or 0 fake VFP registers (d16-d31 or empty)
 648  *      i.e., the user_vfp structure has space for 32 registers even if
 649  *      the kernel doesn't have them all.
 650  *
 651  *      vfp_get() reads this chunk as zero where applicable
 652  *      vfp_set() ignores this chunk
 653  *
 654  * 1 word for the FPSCR
 655  *
 656  * The bounds-checking logic built into user_regset_copyout and friends
 657  * means that we can make a simple sequence of calls to map the relevant data
 658  * to/from the specified slice of the user regset structure.
 659  */
 660 static int vfp_get(struct task_struct *target,
 661                    const struct user_regset *regset,
 662                    unsigned int pos, unsigned int count,
 663                    void *kbuf, void __user *ubuf)
 664 {
 665         int ret;
 666         struct thread_info *thread = task_thread_info(target);
 667         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 668         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 669         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 670
 671         vfp_sync_hwstate(thread);
 672
 673         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 674                                   &vfp->fpregs,
 675                                   user_fpregs_offset,
 676                                   user_fpregs_offset + sizeof(vfp->fpregs));
 677         if (ret)
 678                 return ret;
 679
 680         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 681                                        user_fpregs_offset + sizeof(vfp->fpregs),
 682                                        user_fpscr_offset);
 683         if (ret)
 684                 return ret;
 685
 686         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 687                                    &vfp->fpscr,
 688                                    user_fpscr_offset,
 689                                    user_fpscr_offset + sizeof(vfp->fpscr));
 690 }
 691
 692 /*
 693  * For vfp_set() a read-modify-write is done on the VFP registers,
 694  * in order to avoid writing back a half-modified set of registers on
 695  * failure.
 696  */
 697 static int vfp_set(struct task_struct *target,
 698                           const struct user_regset *regset,
 699                           unsigned int pos, unsigned int count,
 700                           const void *kbuf, const void __user *ubuf)
 701 {
 702         int ret;
 703         struct thread_info *thread = task_thread_info(target);
 704         struct vfp_hard_struct new_vfp;
 705         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 706         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 707
 708         vfp_sync_hwstate(thread);
 709         new_vfp = thread->vfpstate.hard;
 710
 711         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 712                                   &new_vfp.fpregs,
 713                                   user_fpregs_offset,
 714                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 715         if (ret)
 716                 return ret;
 717
 718         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 719                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 720                                 user_fpscr_offset);
 721         if (ret)
 722                 return ret;
 723
 724         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 725                                  &new_vfp.fpscr,
 726                                  user_fpscr_offset,
 727                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 728         if (ret)
 729                 return ret;
 730
 731         vfp_flush_hwstate(thread);
 732         thread->vfpstate.hard = new_vfp;
 733
 734         return 0;
 735 }
 736 #endif /* CONFIG_VFP */
 737
 738 enum arm_regset {
 739         REGSET_GPR,
 740         REGSET_FPR,
 741 #ifdef CONFIG_VFP
 742         REGSET_VFP,
 743 #endif
 744 };
 745
 746 static const struct user_regset arm_regsets[] = {
 747         [REGSET_GPR] = {
 748                 .core_note_type = NT_PRSTATUS,
 749                 .n = ELF_NGREG,
 750                 .size = sizeof(u32),
 751                 .align = sizeof(u32),
 752                 .get = gpr_get,
 753                 .set = gpr_set
 754         },
 755         [REGSET_FPR] = {
 756                 /*
 757                  * For the FPA regs in fpstate, the real fields are a mixture
 758                  * of sizes, so pretend that the registers are word-sized:
 759                  */
 760                 .core_note_type = NT_PRFPREG,
 761                 .n = sizeof(struct user_fp) / sizeof(u32),
 762                 .size = sizeof(u32),
 763                 .align = sizeof(u32),
 764                 .get = fpa_get,
 765                 .set = fpa_set
 766         },
 767 #ifdef CONFIG_VFP
 768         [REGSET_VFP] = {
 769                 /*
 770                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 771                  * a single word dangling at the end of struct user_vfp:
 772                  */
 773                 .core_note_type = NT_ARM_VFP,
 774                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 775                 .size = sizeof(u32),
 776                 .align = sizeof(u32),
 777                 .get = vfp_get,
 778                 .set = vfp_set
 779         },
 780 #endif /* CONFIG_VFP */
 781 };
 782
 783 static const struct user_regset_view user_arm_view = {
 784         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 785         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 786 };
 787
 788 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 789 {
 790         return &user_arm_view;
 791 }
 792
 793 long arch_ptrace(struct task_struct *child, long request,
 794                  unsigned long addr, unsigned long data)
 795 {
 796         int ret;
 797         unsigned long __user *datap = (unsigned long __user *) data;
 798
 799         switch (request) {
 800                 case PTRACE_PEEKUSR:
 801                         ret = ptrace_read_user(child, addr, datap);
 802                         break;
 803
 804                 case PTRACE_POKEUSR:
 805                         ret = ptrace_write_user(child, addr, data);
 806                         break;
 807
 808                 case PTRACE_GETREGS:
 809                         ret = copy_regset_to_user(child,
 810                                                   &user_arm_view, REGSET_GPR,
 811                                                   0, sizeof(struct pt_regs),
 812                                                   datap);
 813                         break;
 814
 815                 case PTRACE_SETREGS:
 816                         ret = copy_regset_from_user(child,
 817                                                     &user_arm_view, REGSET_GPR,
 818                                                     0, sizeof(struct pt_regs),
 819                                                     datap);
 820                         break;
 821
 822                 case PTRACE_GETFPREGS:
 823                         ret = copy_regset_to_user(child,
 824                                                   &user_arm_view, REGSET_FPR,
 825                                                   0, sizeof(union fp_state),
 826                                                   datap);
 827                         break;
 828
 829                 case PTRACE_SETFPREGS:
 830                         ret = copy_regset_from_user(child,
 831                                                     &user_arm_view, REGSET_FPR,
 832                                                     0, sizeof(union fp_state),
 833                                                     datap);
 834                         break;
 835
 836 #ifdef CONFIG_IWMMXT
 837                 case PTRACE_GETWMMXREGS:
 838                         ret = ptrace_getwmmxregs(child, datap);
 839                         break;
 840
 841                 case PTRACE_SETWMMXREGS:
 842                         ret = ptrace_setwmmxregs(child, datap);
 843                         break;
 844 #endif
 845
 846                 case PTRACE_GET_THREAD_AREA:
 847                         ret = put_user(task_thread_info(child)->tp_value,
 848                                        datap);
 849                         break;
 850
 851                 case PTRACE_SET_SYSCALL:
 852                         task_thread_info(child)->syscall = data;
 853                         ret = 0;
 854                         break;
 855
 856 #ifdef CONFIG_CRUNCH
 857                 case PTRACE_GETCRUNCHREGS:
 858                         ret = ptrace_getcrunchregs(child, datap);
 859                         break;
 860
 861                 case PTRACE_SETCRUNCHREGS:
 862                         ret = ptrace_setcrunchregs(child, datap);
 863                         break;
 864 #endif
 865
 866 #ifdef CONFIG_VFP
 867                 case PTRACE_GETVFPREGS:
 868                         ret = copy_regset_to_user(child,
 869                                                   &user_arm_view, REGSET_VFP,
 870                                                   0, ARM_VFPREGS_SIZE,
 871                                                   datap);
 872                         break;
 873
 874                 case PTRACE_SETVFPREGS:
 875                         ret = copy_regset_from_user(child,
 876                                                     &user_arm_view, REGSET_VFP,
 877                                                     0, ARM_VFPREGS_SIZE,
 878                                                     datap);
 879                         break;
 880 #endif
 881
 882 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 883                 case PTRACE_GETHBPREGS:
 884                         if (ptrace_get_breakpoints(child) < 0)
 885                                 return -ESRCH;
 886
 887                         ret = ptrace_gethbpregs(child, addr,
 888                                                 (unsigned long __user *)data);
 889                         ptrace_put_breakpoints(child);
 890                         break;
 891                 case PTRACE_SETHBPREGS:
 892                         if (ptrace_get_breakpoints(child) < 0)
 893                                 return -ESRCH;
 894
 895                         ret = ptrace_sethbpregs(child, addr,
 896                                                 (unsigned long __user *)data);
 897                         ptrace_put_breakpoints(child);
 898                         break;
 899 #endif
 900
 901                 default:
 902                         ret = ptrace_request(child, request, addr, data);
 903                         break;
 904         }
 905
 906         return ret;
 907 }
 908
 909 asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 910 {
 911         unsigned long ip;
 912
 913         if (why)
 914                 audit_syscall_exit(regs);
 915         else
 916                 audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0,
 917                                     regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
 918
 919         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 920                 return scno;
 921         if (!(current->ptrace & PT_PTRACED))
 922                 return scno;
 923
 924         current_thread_info()->syscall = scno;
 925
 926         /*
 927          * IP is used to denote syscall entry/exit:
 928          * IP = 0 -> entry, =1 -> exit
 929          */
 930         ip = regs->ARM_ip;
 931         regs->ARM_ip = why;
 932
 933         /* the 0x80 provides a way for the tracing parent to distinguish
 934            between a syscall stop and SIGTRAP delivery */
 935         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 936                                  ? 0x80 : 0));
 937         /*
 938          * this isn't the same as continuing with a signal, but it will do
 939          * for normal use.  strace only continues with a signal if the
 940          * stopping signal is not SIGTRAP.  -brl
 941          */
 942         if (current->exit_code) {
 943                 send_sig(current->exit_code, current, 1);
 944                 current->exit_code = 0;
 945         }
 946         regs->ARM_ip = ip;
 947
 948         return current_thread_info()->syscall;
 949 }