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 #include <linux/tracehook.h>
  28 #include <linux/unistd.h>
  29
  30 #include <asm/pgtable.h>
  31 #include <asm/traps.h>
  32
  33 #define CREATE_TRACE_POINTS
  34 #include <trace/events/syscalls.h>
  35
  36 #define REG_PC  15
  37 #define REG_PSR 16
  38 /*
  39  * does not yet catch signals sent when the child dies.
  40  * in exit.c or in signal.c.
  41  */
  42
  43 #if 0
  44 /*
  45  * Breakpoint SWI instruction: SWI &9F0001
  46  */
  47 #define BREAKINST_ARM   0xef9f0001
  48 #define BREAKINST_THUMB 0xdf00          /* fill this in later */
  49 #else
  50 /*
  51  * New breakpoints - use an undefined instruction.  The ARM architecture
  52  * reference manual guarantees that the following instruction space
  53  * will produce an undefined instruction exception on all CPUs:
  54  *
  55  *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
  56  *  Thumb: 1101 1110 xxxx xxxx
  57  */
  58 #define BREAKINST_ARM   0xe7f001f0
  59 #define BREAKINST_THUMB 0xde01
  60 #endif
  61
  62 struct pt_regs_offset {
  63         const char *name;
  64         int offset;
  65 };
  66
  67 #define REG_OFFSET_NAME(r) \
  68         {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
  69 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  70
  71 static const struct pt_regs_offset regoffset_table[] = {
  72         REG_OFFSET_NAME(r0),
  73         REG_OFFSET_NAME(r1),
  74         REG_OFFSET_NAME(r2),
  75         REG_OFFSET_NAME(r3),
  76         REG_OFFSET_NAME(r4),
  77         REG_OFFSET_NAME(r5),
  78         REG_OFFSET_NAME(r6),
  79         REG_OFFSET_NAME(r7),
  80         REG_OFFSET_NAME(r8),
  81         REG_OFFSET_NAME(r9),
  82         REG_OFFSET_NAME(r10),
  83         REG_OFFSET_NAME(fp),
  84         REG_OFFSET_NAME(ip),
  85         REG_OFFSET_NAME(sp),
  86         REG_OFFSET_NAME(lr),
  87         REG_OFFSET_NAME(pc),
  88         REG_OFFSET_NAME(cpsr),
  89         REG_OFFSET_NAME(ORIG_r0),
  90         REG_OFFSET_END,
  91 };
  92
  93 /**
  94  * regs_query_register_offset() - query register offset from its name
  95  * @name:       the name of a register
  96  *
  97  * regs_query_register_offset() returns the offset of a register in struct
  98  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
  99  */
 100 int regs_query_register_offset(const char *name)
 101 {
 102         const struct pt_regs_offset *roff;
 103         for (roff = regoffset_table; roff->name != NULL; roff++)
 104                 if (!strcmp(roff->name, name))
 105                         return roff->offset;
 106         return -EINVAL;
 107 }
 108
 109 /**
 110  * regs_query_register_name() - query register name from its offset
 111  * @offset:     the offset of a register in struct pt_regs.
 112  *
 113  * regs_query_register_name() returns the name of a register from its
 114  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 115  */
 116 const char *regs_query_register_name(unsigned int offset)
 117 {
 118         const struct pt_regs_offset *roff;
 119         for (roff = regoffset_table; roff->name != NULL; roff++)
 120                 if (roff->offset == offset)
 121                         return roff->name;
 122         return NULL;
 123 }
 124
 125 /**
 126  * regs_within_kernel_stack() - check the address in the stack
 127  * @regs:      pt_regs which contains kernel stack pointer.
 128  * @addr:      address which is checked.
 129  *
 130  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 131  * If @addr is within the kernel stack, it returns true. If not, returns false.
 132  */
 133 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 134 {
 135         return ((addr & ~(THREAD_SIZE - 1))  ==
 136                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 137 }
 138
 139 /**
 140  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 141  * @regs:       pt_regs which contains kernel stack pointer.
 142  * @n:          stack entry number.
 143  *
 144  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 145  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 146  * this returns 0.
 147  */
 148 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 149 {
 150         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 151         addr += n;
 152         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 153                 return *addr;
 154         else
 155                 return 0;
 156 }
 157
 158 /*
 159  * this routine will get a word off of the processes privileged stack.
 160  * the offset is how far from the base addr as stored in the THREAD.
 161  * this routine assumes that all the privileged stacks are in our
 162  * data space.
 163  */
 164 static inline long get_user_reg(struct task_struct *task, int offset)
 165 {
 166         return task_pt_regs(task)->uregs[offset];
 167 }
 168
 169 /*
 170  * this routine will put a word on the processes privileged stack.
 171  * the offset is how far from the base addr as stored in the THREAD.
 172  * this routine assumes that all the privileged stacks are in our
 173  * data space.
 174  */
 175 static inline int
 176 put_user_reg(struct task_struct *task, int offset, long data)
 177 {
 178         struct pt_regs newregs, *regs = task_pt_regs(task);
 179         int ret = -EINVAL;
 180
 181         newregs = *regs;
 182         newregs.uregs[offset] = data;
 183
 184         if (valid_user_regs(&newregs)) {
 185                 regs->uregs[offset] = data;
 186                 ret = 0;
 187         }
 188
 189         return ret;
 190 }
 191
 192 /*
 193  * Called by kernel/ptrace.c when detaching..
 194  */
 195 void ptrace_disable(struct task_struct *child)
 196 {
 197         /* Nothing to do. */
 198 }
 199
 200 /*
 201  * Handle hitting a breakpoint.
 202  */
 203 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
 204 {
 205         siginfo_t info;
 206
 207         info.si_signo = SIGTRAP;
 208         info.si_errno = 0;
 209         info.si_code  = TRAP_BRKPT;
 210         info.si_addr  = (void __user *)instruction_pointer(regs);
 211
 212         force_sig_info(SIGTRAP, &info, tsk);
 213 }
 214
 215 static int break_trap(struct pt_regs *regs, unsigned int instr)
 216 {
 217         ptrace_break(current, regs);
 218         return 0;
 219 }
 220
 221 static struct undef_hook arm_break_hook = {
 222         .instr_mask     = 0x0fffffff,
 223         .instr_val      = 0x07f001f0,
 224         .cpsr_mask      = PSR_T_BIT,
 225         .cpsr_val       = 0,
 226         .fn             = break_trap,
 227 };
 228
 229 static struct undef_hook thumb_break_hook = {
 230         .instr_mask     = 0xffff,
 231         .instr_val      = 0xde01,
 232         .cpsr_mask      = PSR_T_BIT,
 233         .cpsr_val       = PSR_T_BIT,
 234         .fn             = break_trap,
 235 };
 236
 237 static struct undef_hook thumb2_break_hook = {
 238         .instr_mask     = 0xffffffff,
 239         .instr_val      = 0xf7f0a000,
 240         .cpsr_mask      = PSR_T_BIT,
 241         .cpsr_val       = PSR_T_BIT,
 242         .fn             = break_trap,
 243 };
 244
 245 static int __init ptrace_break_init(void)
 246 {
 247         register_undef_hook(&arm_break_hook);
 248         register_undef_hook(&thumb_break_hook);
 249         register_undef_hook(&thumb2_break_hook);
 250         return 0;
 251 }
 252
 253 core_initcall(ptrace_break_init);
 254
 255 /*
 256  * Read the word at offset "off" into the "struct user".  We
 257  * actually access the pt_regs stored on the kernel stack.
 258  */
 259 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 260                             unsigned long __user *ret)
 261 {
 262         unsigned long tmp;
 263
 264         if (off & 3)
 265                 return -EIO;
 266
 267         tmp = 0;
 268         if (off == PT_TEXT_ADDR)
 269                 tmp = tsk->mm->start_code;
 270         else if (off == PT_DATA_ADDR)
 271                 tmp = tsk->mm->start_data;
 272         else if (off == PT_TEXT_END_ADDR)
 273                 tmp = tsk->mm->end_code;
 274         else if (off < sizeof(struct pt_regs))
 275                 tmp = get_user_reg(tsk, off >> 2);
 276         else if (off >= sizeof(struct user))
 277                 return -EIO;
 278
 279         return put_user(tmp, ret);
 280 }
 281
 282 /*
 283  * Write the word at offset "off" into "struct user".  We
 284  * actually access the pt_regs stored on the kernel stack.
 285  */
 286 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 287                              unsigned long val)
 288 {
 289         if (off & 3 || off >= sizeof(struct user))
 290                 return -EIO;
 291
 292         if (off >= sizeof(struct pt_regs))
 293                 return 0;
 294
 295         return put_user_reg(tsk, off >> 2, val);
 296 }
 297
 298 #ifdef CONFIG_IWMMXT
 299
 300 /*
 301  * Get the child iWMMXt state.
 302  */
 303 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 304 {
 305         struct thread_info *thread = task_thread_info(tsk);
 306
 307         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 308                 return -ENODATA;
 309         iwmmxt_task_disable(thread);  /* force it to ram */
 310         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 311                 ? -EFAULT : 0;
 312 }
 313
 314 /*
 315  * Set the child iWMMXt state.
 316  */
 317 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 318 {
 319         struct thread_info *thread = task_thread_info(tsk);
 320
 321         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 322                 return -EACCES;
 323         iwmmxt_task_release(thread);  /* force a reload */
 324         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 325                 ? -EFAULT : 0;
 326 }
 327
 328 #endif
 329
 330 #ifdef CONFIG_CRUNCH
 331 /*
 332  * Get the child Crunch state.
 333  */
 334 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 335 {
 336         struct thread_info *thread = task_thread_info(tsk);
 337
 338         crunch_task_disable(thread);  /* force it to ram */
 339         return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 340                 ? -EFAULT : 0;
 341 }
 342
 343 /*
 344  * Set the child Crunch state.
 345  */
 346 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 347 {
 348         struct thread_info *thread = task_thread_info(tsk);
 349
 350         crunch_task_release(thread);  /* force a reload */
 351         return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 352                 ? -EFAULT : 0;
 353 }
 354 #endif
 355
 356 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 357 /*
 358  * Convert a virtual register number into an index for a thread_info
 359  * breakpoint array. Breakpoints are identified using positive numbers
 360  * whilst watchpoints are negative. The registers are laid out as pairs
 361  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 362  * Register 0 is reserved for describing resource information.
 363  */
 364 static int ptrace_hbp_num_to_idx(long num)
 365 {
 366         if (num < 0)
 367                 num = (ARM_MAX_BRP << 1) - num;
 368         return (num - 1) >> 1;
 369 }
 370
 371 /*
 372  * Returns the virtual register number for the address of the
 373  * breakpoint at index idx.
 374  */
 375 static long ptrace_hbp_idx_to_num(int idx)
 376 {
 377         long mid = ARM_MAX_BRP << 1;
 378         long num = (idx << 1) + 1;
 379         return num > mid ? mid - num : num;
 380 }
 381
 382 /*
 383  * Handle hitting a HW-breakpoint.
 384  */
 385 static void ptrace_hbptriggered(struct perf_event *bp,
 386                                      struct perf_sample_data *data,
 387                                      struct pt_regs *regs)
 388 {
 389         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 390         long num;
 391         int i;
 392         siginfo_t info;
 393
 394         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 395                 if (current->thread.debug.hbp[i] == bp)
 396                         break;
 397
 398         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 399
 400         info.si_signo   = SIGTRAP;
 401         info.si_errno   = (int)num;
 402         info.si_code    = TRAP_HWBKPT;
 403         info.si_addr    = (void __user *)(bkpt->trigger);
 404
 405         force_sig_info(SIGTRAP, &info, current);
 406 }
 407
 408 /*
 409  * Set ptrace breakpoint pointers to zero for this task.
 410  * This is required in order to prevent child processes from unregistering
 411  * breakpoints held by their parent.
 412  */
 413 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 414 {
 415         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 416 }
 417
 418 /*
 419  * Unregister breakpoints from this task and reset the pointers in
 420  * the thread_struct.
 421  */
 422 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 423 {
 424         int i;
 425         struct thread_struct *t = &tsk->thread;
 426
 427         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 428                 if (t->debug.hbp[i]) {
 429                         unregister_hw_breakpoint(t->debug.hbp[i]);
 430                         t->debug.hbp[i] = NULL;
 431                 }
 432         }
 433 }
 434
 435 static u32 ptrace_get_hbp_resource_info(void)
 436 {
 437         u8 num_brps, num_wrps, debug_arch, wp_len;
 438         u32 reg = 0;
 439
 440         num_brps        = hw_breakpoint_slots(TYPE_INST);
 441         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 442         debug_arch      = arch_get_debug_arch();
 443         wp_len          = arch_get_max_wp_len();
 444
 445         reg             |= debug_arch;
 446         reg             <<= 8;
 447         reg             |= wp_len;
 448         reg             <<= 8;
 449         reg             |= num_wrps;
 450         reg             <<= 8;
 451         reg             |= num_brps;
 452
 453         return reg;
 454 }
 455
 456 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 457 {
 458         struct perf_event_attr attr;
 459
 460         ptrace_breakpoint_init(&attr);
 461
 462         /* Initialise fields to sane defaults. */
 463         attr.bp_addr    = 0;
 464         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 465         attr.bp_type    = type;
 466         attr.disabled   = 1;
 467
 468         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 469                                            tsk);
 470 }
 471
 472 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 473                              unsigned long  __user *data)
 474 {
 475         u32 reg;
 476         int idx, ret = 0;
 477         struct perf_event *bp;
 478         struct arch_hw_breakpoint_ctrl arch_ctrl;
 479
 480         if (num == 0) {
 481                 reg = ptrace_get_hbp_resource_info();
 482         } else {
 483                 idx = ptrace_hbp_num_to_idx(num);
 484                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 485                         ret = -EINVAL;
 486                         goto out;
 487                 }
 488
 489                 bp = tsk->thread.debug.hbp[idx];
 490                 if (!bp) {
 491                         reg = 0;
 492                         goto put;
 493                 }
 494
 495                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 496
 497                 /*
 498                  * Fix up the len because we may have adjusted it
 499                  * to compensate for an unaligned address.
 500                  */
 501                 while (!(arch_ctrl.len & 0x1))
 502                         arch_ctrl.len >>= 1;
 503
 504                 if (num & 0x1)
 505                         reg = bp->attr.bp_addr;
 506                 else
 507                         reg = encode_ctrl_reg(arch_ctrl);
 508         }
 509
 510 put:
 511         if (put_user(reg, data))
 512                 ret = -EFAULT;
 513
 514 out:
 515         return ret;
 516 }
 517
 518 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 519                              unsigned long __user *data)
 520 {
 521         int idx, gen_len, gen_type, implied_type, ret = 0;
 522         u32 user_val;
 523         struct perf_event *bp;
 524         struct arch_hw_breakpoint_ctrl ctrl;
 525         struct perf_event_attr attr;
 526
 527         if (num == 0)
 528                 goto out;
 529         else if (num < 0)
 530                 implied_type = HW_BREAKPOINT_RW;
 531         else
 532                 implied_type = HW_BREAKPOINT_X;
 533
 534         idx = ptrace_hbp_num_to_idx(num);
 535         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 536                 ret = -EINVAL;
 537                 goto out;
 538         }
 539
 540         if (get_user(user_val, data)) {
 541                 ret = -EFAULT;
 542                 goto out;
 543         }
 544
 545         bp = tsk->thread.debug.hbp[idx];
 546         if (!bp) {
 547                 bp = ptrace_hbp_create(tsk, implied_type);
 548                 if (IS_ERR(bp)) {
 549                         ret = PTR_ERR(bp);
 550                         goto out;
 551                 }
 552                 tsk->thread.debug.hbp[idx] = bp;
 553         }
 554
 555         attr = bp->attr;
 556
 557         if (num & 0x1) {
 558                 /* Address */
 559                 attr.bp_addr    = user_val;
 560         } else {
 561                 /* Control */
 562                 decode_ctrl_reg(user_val, &ctrl);
 563                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 564                 if (ret)
 565                         goto out;
 566
 567                 if ((gen_type & implied_type) != gen_type) {
 568                         ret = -EINVAL;
 569                         goto out;
 570                 }
 571
 572                 attr.bp_len     = gen_len;
 573                 attr.bp_type    = gen_type;
 574                 attr.disabled   = !ctrl.enabled;
 575         }
 576
 577         ret = modify_user_hw_breakpoint(bp, &attr);
 578 out:
 579         return ret;
 580 }
 581 #endif
 582
 583 /* regset get/set implementations */
 584
 585 static int gpr_get(struct task_struct *target,
 586                    const struct user_regset *regset,
 587                    unsigned int pos, unsigned int count,
 588                    void *kbuf, void __user *ubuf)
 589 {
 590         struct pt_regs *regs = task_pt_regs(target);
 591
 592         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 593                                    regs,
 594                                    0, sizeof(*regs));
 595 }
 596
 597 static int gpr_set(struct task_struct *target,
 598                    const struct user_regset *regset,
 599                    unsigned int pos, unsigned int count,
 600                    const void *kbuf, const void __user *ubuf)
 601 {
 602         int ret;
 603         struct pt_regs newregs;
 604
 605         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 606                                  &newregs,
 607                                  0, sizeof(newregs));
 608         if (ret)
 609                 return ret;
 610
 611         if (!valid_user_regs(&newregs))
 612                 return -EINVAL;
 613
 614         *task_pt_regs(target) = newregs;
 615         return 0;
 616 }
 617
 618 static int fpa_get(struct task_struct *target,
 619                    const struct user_regset *regset,
 620                    unsigned int pos, unsigned int count,
 621                    void *kbuf, void __user *ubuf)
 622 {
 623         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 624                                    &task_thread_info(target)->fpstate,
 625                                    0, sizeof(struct user_fp));
 626 }
 627
 628 static int fpa_set(struct task_struct *target,
 629                    const struct user_regset *regset,
 630                    unsigned int pos, unsigned int count,
 631                    const void *kbuf, const void __user *ubuf)
 632 {
 633         struct thread_info *thread = task_thread_info(target);
 634
 635         thread->used_cp[1] = thread->used_cp[2] = 1;
 636
 637         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 638                 &thread->fpstate,
 639                 0, sizeof(struct user_fp));
 640 }
 641
 642 #ifdef CONFIG_VFP
 643 /*
 644  * VFP register get/set implementations.
 645  *
 646  * With respect to the kernel, struct user_fp is divided into three chunks:
 647  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 648  *      These are transferred to/from the real registers in the task's
 649  *      vfp_hard_struct.  The number of registers depends on the kernel
 650  *      configuration.
 651  *
 652  * 16 or 0 fake VFP registers (d16-d31 or empty)
 653  *      i.e., the user_vfp structure has space for 32 registers even if
 654  *      the kernel doesn't have them all.
 655  *
 656  *      vfp_get() reads this chunk as zero where applicable
 657  *      vfp_set() ignores this chunk
 658  *
 659  * 1 word for the FPSCR
 660  *
 661  * The bounds-checking logic built into user_regset_copyout and friends
 662  * means that we can make a simple sequence of calls to map the relevant data
 663  * to/from the specified slice of the user regset structure.
 664  */
 665 static int vfp_get(struct task_struct *target,
 666                    const struct user_regset *regset,
 667                    unsigned int pos, unsigned int count,
 668                    void *kbuf, void __user *ubuf)
 669 {
 670         int ret;
 671         struct thread_info *thread = task_thread_info(target);
 672         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 673         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 674         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 675
 676         vfp_sync_hwstate(thread);
 677
 678         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 679                                   &vfp->fpregs,
 680                                   user_fpregs_offset,
 681                                   user_fpregs_offset + sizeof(vfp->fpregs));
 682         if (ret)
 683                 return ret;
 684
 685         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 686                                        user_fpregs_offset + sizeof(vfp->fpregs),
 687                                        user_fpscr_offset);
 688         if (ret)
 689                 return ret;
 690
 691         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 692                                    &vfp->fpscr,
 693                                    user_fpscr_offset,
 694                                    user_fpscr_offset + sizeof(vfp->fpscr));
 695 }
 696
 697 /*
 698  * For vfp_set() a read-modify-write is done on the VFP registers,
 699  * in order to avoid writing back a half-modified set of registers on
 700  * failure.
 701  */
 702 static int vfp_set(struct task_struct *target,
 703                           const struct user_regset *regset,
 704                           unsigned int pos, unsigned int count,
 705                           const void *kbuf, const void __user *ubuf)
 706 {
 707         int ret;
 708         struct thread_info *thread = task_thread_info(target);
 709         struct vfp_hard_struct new_vfp;
 710         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 711         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 712
 713         vfp_sync_hwstate(thread);
 714         new_vfp = thread->vfpstate.hard;
 715
 716         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 717                                   &new_vfp.fpregs,
 718                                   user_fpregs_offset,
 719                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 720         if (ret)
 721                 return ret;
 722
 723         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 724                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 725                                 user_fpscr_offset);
 726         if (ret)
 727                 return ret;
 728
 729         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 730                                  &new_vfp.fpscr,
 731                                  user_fpscr_offset,
 732                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 733         if (ret)
 734                 return ret;
 735
 736         vfp_flush_hwstate(thread);
 737         thread->vfpstate.hard = new_vfp;
 738
 739         return 0;
 740 }
 741 #endif /* CONFIG_VFP */
 742
 743 enum arm_regset {
 744         REGSET_GPR,
 745         REGSET_FPR,
 746 #ifdef CONFIG_VFP
 747         REGSET_VFP,
 748 #endif
 749 };
 750
 751 static const struct user_regset arm_regsets[] = {
 752         [REGSET_GPR] = {
 753                 .core_note_type = NT_PRSTATUS,
 754                 .n = ELF_NGREG,
 755                 .size = sizeof(u32),
 756                 .align = sizeof(u32),
 757                 .get = gpr_get,
 758                 .set = gpr_set
 759         },
 760         [REGSET_FPR] = {
 761                 /*
 762                  * For the FPA regs in fpstate, the real fields are a mixture
 763                  * of sizes, so pretend that the registers are word-sized:
 764                  */
 765                 .core_note_type = NT_PRFPREG,
 766                 .n = sizeof(struct user_fp) / sizeof(u32),
 767                 .size = sizeof(u32),
 768                 .align = sizeof(u32),
 769                 .get = fpa_get,
 770                 .set = fpa_set
 771         },
 772 #ifdef CONFIG_VFP
 773         [REGSET_VFP] = {
 774                 /*
 775                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 776                  * a single word dangling at the end of struct user_vfp:
 777                  */
 778                 .core_note_type = NT_ARM_VFP,
 779                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 780                 .size = sizeof(u32),
 781                 .align = sizeof(u32),
 782                 .get = vfp_get,
 783                 .set = vfp_set
 784         },
 785 #endif /* CONFIG_VFP */
 786 };
 787
 788 static const struct user_regset_view user_arm_view = {
 789         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 790         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 791 };
 792
 793 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 794 {
 795         return &user_arm_view;
 796 }
 797
 798 long arch_ptrace(struct task_struct *child, long request,
 799                  unsigned long addr, unsigned long data)
 800 {
 801         int ret;
 802         unsigned long __user *datap = (unsigned long __user *) data;
 803
 804         switch (request) {
 805                 case PTRACE_PEEKUSR:
 806                         ret = ptrace_read_user(child, addr, datap);
 807                         break;
 808
 809                 case PTRACE_POKEUSR:
 810                         ret = ptrace_write_user(child, addr, data);
 811                         break;
 812
 813                 case PTRACE_GETREGS:
 814                         ret = copy_regset_to_user(child,
 815                                                   &user_arm_view, REGSET_GPR,
 816                                                   0, sizeof(struct pt_regs),
 817                                                   datap);
 818                         break;
 819
 820                 case PTRACE_SETREGS:
 821                         ret = copy_regset_from_user(child,
 822                                                     &user_arm_view, REGSET_GPR,
 823                                                     0, sizeof(struct pt_regs),
 824                                                     datap);
 825                         break;
 826
 827                 case PTRACE_GETFPREGS:
 828                         ret = copy_regset_to_user(child,
 829                                                   &user_arm_view, REGSET_FPR,
 830                                                   0, sizeof(union fp_state),
 831                                                   datap);
 832                         break;
 833
 834                 case PTRACE_SETFPREGS:
 835                         ret = copy_regset_from_user(child,
 836                                                     &user_arm_view, REGSET_FPR,
 837                                                     0, sizeof(union fp_state),
 838                                                     datap);
 839                         break;
 840
 841 #ifdef CONFIG_IWMMXT
 842                 case PTRACE_GETWMMXREGS:
 843                         ret = ptrace_getwmmxregs(child, datap);
 844                         break;
 845
 846                 case PTRACE_SETWMMXREGS:
 847                         ret = ptrace_setwmmxregs(child, datap);
 848                         break;
 849 #endif
 850
 851                 case PTRACE_GET_THREAD_AREA:
 852                         ret = put_user(task_thread_info(child)->tp_value,
 853                                        datap);
 854                         break;
 855
 856                 case PTRACE_SET_SYSCALL:
 857                         task_thread_info(child)->syscall = data;
 858                         ret = 0;
 859                         break;
 860
 861 #ifdef CONFIG_CRUNCH
 862                 case PTRACE_GETCRUNCHREGS:
 863                         ret = ptrace_getcrunchregs(child, datap);
 864                         break;
 865
 866                 case PTRACE_SETCRUNCHREGS:
 867                         ret = ptrace_setcrunchregs(child, datap);
 868                         break;
 869 #endif
 870
 871 #ifdef CONFIG_VFP
 872                 case PTRACE_GETVFPREGS:
 873                         ret = copy_regset_to_user(child,
 874                                                   &user_arm_view, REGSET_VFP,
 875                                                   0, ARM_VFPREGS_SIZE,
 876                                                   datap);
 877                         break;
 878
 879                 case PTRACE_SETVFPREGS:
 880                         ret = copy_regset_from_user(child,
 881                                                     &user_arm_view, REGSET_VFP,
 882                                                     0, ARM_VFPREGS_SIZE,
 883                                                     datap);
 884                         break;
 885 #endif
 886
 887 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 888                 case PTRACE_GETHBPREGS:
 889                         if (ptrace_get_breakpoints(child) < 0)
 890                                 return -ESRCH;
 891
 892                         ret = ptrace_gethbpregs(child, addr,
 893                                                 (unsigned long __user *)data);
 894                         ptrace_put_breakpoints(child);
 895                         break;
 896                 case PTRACE_SETHBPREGS:
 897                         if (ptrace_get_breakpoints(child) < 0)
 898                                 return -ESRCH;
 899
 900                         ret = ptrace_sethbpregs(child, addr,
 901                                                 (unsigned long __user *)data);
 902                         ptrace_put_breakpoints(child);
 903                         break;
 904 #endif
 905
 906                 default:
 907                         ret = ptrace_request(child, request, addr, data);
 908                         break;
 909         }
 910
 911         return ret;
 912 }
 913
 914 enum ptrace_syscall_dir {
 915         PTRACE_SYSCALL_ENTER = 0,
 916         PTRACE_SYSCALL_EXIT,
 917 };
 918
 919 static void tracehook_report_syscall(struct pt_regs *regs,
 920                                     enum ptrace_syscall_dir dir)
 921 {
 922         unsigned long ip;
 923
 924         /*
 925          * IP is used to denote syscall entry/exit:
 926          * IP = 0 -> entry, =1 -> exit
 927          */
 928         ip = regs->ARM_ip;
 929         regs->ARM_ip = dir;
 930
 931         if (dir == PTRACE_SYSCALL_EXIT)
 932                 tracehook_report_syscall_exit(regs, 0);
 933         else if (tracehook_report_syscall_entry(regs))
 934                 current_thread_info()->syscall = -1;
 935
 936         regs->ARM_ip = ip;
 937 }
 938
 939 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 940 {
 941         current_thread_info()->syscall = scno;
 942
 943         /* Do the secure computing check first; failures should be fast. */
 944         if (secure_computing(scno) == -1)
 945                 return -1;
 946
 947         if (test_thread_flag(TIF_SYSCALL_TRACE))
 948                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 949
 950         scno = current_thread_info()->syscall;
 951
 952         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 953                 trace_sys_enter(regs, scno);
 954
 955         audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1,
 956                             regs->ARM_r2, regs->ARM_r3);
 957
 958         return scno;
 959 }
 960
 961 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 962 {
 963         /*
 964          * Audit the syscall before anything else, as a debugger may
 965          * come in and change the current registers.
 966          */
 967         audit_syscall_exit(regs);
 968
 969         /*
 970          * Note that we haven't updated the ->syscall field for the
 971          * current thread. This isn't a problem because it will have
 972          * been set on syscall entry and there hasn't been an opportunity
 973          * for a PTRACE_SET_SYSCALL since then.
 974          */
 975         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 976                 trace_sys_exit(regs, regs_return_value(regs));
 977
 978         if (test_thread_flag(TIF_SYSCALL_TRACE))
 979                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 980 }