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/signal.h>
  14 #include <linux/sched/task_stack.h>
  15 #include <linux/mm.h>
  16 #include <linux/elf.h>
  17 #include <linux/smp.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/security.h>
  21 #include <linux/init.h>
  22 #include <linux/signal.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/perf_event.h>
  25 #include <linux/hw_breakpoint.h>
  26 #include <linux/regset.h>
  27 #include <linux/audit.h>
  28 #include <linux/tracehook.h>
  29 #include <linux/unistd.h>
  30
  31 #include <asm/pgtable.h>
  32 #include <asm/traps.h>
  33
  34 #define CREATE_TRACE_POINTS
  35 #include <trace/events/syscalls.h>
  36
  37 #define REG_PC  15
  38 #define REG_PSR 16
  39 /*
  40  * does not yet catch signals sent when the child dies.
  41  * in exit.c or in signal.c.
  42  */
  43
  44 #if 0
  45 /*
  46  * Breakpoint SWI instruction: SWI &9F0001
  47  */
  48 #define BREAKINST_ARM   0xef9f0001
  49 #define BREAKINST_THUMB 0xdf00          /* fill this in later */
  50 #else
  51 /*
  52  * New breakpoints - use an undefined instruction.  The ARM architecture
  53  * reference manual guarantees that the following instruction space
  54  * will produce an undefined instruction exception on all CPUs:
  55  *
  56  *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
  57  *  Thumb: 1101 1110 xxxx xxxx
  58  */
  59 #define BREAKINST_ARM   0xe7f001f0
  60 #define BREAKINST_THUMB 0xde01
  61 #endif
  62
  63 struct pt_regs_offset {
  64         const char *name;
  65         int offset;
  66 };
  67
  68 #define REG_OFFSET_NAME(r) \
  69         {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
  70 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  71
  72 static const struct pt_regs_offset regoffset_table[] = {
  73         REG_OFFSET_NAME(r0),
  74         REG_OFFSET_NAME(r1),
  75         REG_OFFSET_NAME(r2),
  76         REG_OFFSET_NAME(r3),
  77         REG_OFFSET_NAME(r4),
  78         REG_OFFSET_NAME(r5),
  79         REG_OFFSET_NAME(r6),
  80         REG_OFFSET_NAME(r7),
  81         REG_OFFSET_NAME(r8),
  82         REG_OFFSET_NAME(r9),
  83         REG_OFFSET_NAME(r10),
  84         REG_OFFSET_NAME(fp),
  85         REG_OFFSET_NAME(ip),
  86         REG_OFFSET_NAME(sp),
  87         REG_OFFSET_NAME(lr),
  88         REG_OFFSET_NAME(pc),
  89         REG_OFFSET_NAME(cpsr),
  90         REG_OFFSET_NAME(ORIG_r0),
  91         REG_OFFSET_END,
  92 };
  93
  94 /**
  95  * regs_query_register_offset() - query register offset from its name
  96  * @name:       the name of a register
  97  *
  98  * regs_query_register_offset() returns the offset of a register in struct
  99  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 100  */
 101 int regs_query_register_offset(const char *name)
 102 {
 103         const struct pt_regs_offset *roff;
 104         for (roff = regoffset_table; roff->name != NULL; roff++)
 105                 if (!strcmp(roff->name, name))
 106                         return roff->offset;
 107         return -EINVAL;
 108 }
 109
 110 /**
 111  * regs_query_register_name() - query register name from its offset
 112  * @offset:     the offset of a register in struct pt_regs.
 113  *
 114  * regs_query_register_name() returns the name of a register from its
 115  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 116  */
 117 const char *regs_query_register_name(unsigned int offset)
 118 {
 119         const struct pt_regs_offset *roff;
 120         for (roff = regoffset_table; roff->name != NULL; roff++)
 121                 if (roff->offset == offset)
 122                         return roff->name;
 123         return NULL;
 124 }
 125
 126 /**
 127  * regs_within_kernel_stack() - check the address in the stack
 128  * @regs:      pt_regs which contains kernel stack pointer.
 129  * @addr:      address which is checked.
 130  *
 131  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 132  * If @addr is within the kernel stack, it returns true. If not, returns false.
 133  */
 134 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 135 {
 136         return ((addr & ~(THREAD_SIZE - 1))  ==
 137                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 138 }
 139
 140 /**
 141  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 142  * @regs:       pt_regs which contains kernel stack pointer.
 143  * @n:          stack entry number.
 144  *
 145  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 146  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 147  * this returns 0.
 148  */
 149 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 150 {
 151         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 152         addr += n;
 153         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 154                 return *addr;
 155         else
 156                 return 0;
 157 }
 158
 159 /*
 160  * this routine will get a word off of the processes privileged stack.
 161  * the offset is how far from the base addr as stored in the THREAD.
 162  * this routine assumes that all the privileged stacks are in our
 163  * data space.
 164  */
 165 static inline long get_user_reg(struct task_struct *task, int offset)
 166 {
 167         return task_pt_regs(task)->uregs[offset];
 168 }
 169
 170 /*
 171  * this routine will put a word on the processes privileged stack.
 172  * the offset is how far from the base addr as stored in the THREAD.
 173  * this routine assumes that all the privileged stacks are in our
 174  * data space.
 175  */
 176 static inline int
 177 put_user_reg(struct task_struct *task, int offset, long data)
 178 {
 179         struct pt_regs newregs, *regs = task_pt_regs(task);
 180         int ret = -EINVAL;
 181
 182         newregs = *regs;
 183         newregs.uregs[offset] = data;
 184
 185         if (valid_user_regs(&newregs)) {
 186                 regs->uregs[offset] = data;
 187                 ret = 0;
 188         }
 189
 190         return ret;
 191 }
 192
 193 /*
 194  * Called by kernel/ptrace.c when detaching..
 195  */
 196 void ptrace_disable(struct task_struct *child)
 197 {
 198         /* Nothing to do. */
 199 }
 200
 201 /*
 202  * Handle hitting a breakpoint.
 203  */
 204 void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
 205 {
 206         siginfo_t info;
 207
 208         info.si_signo = SIGTRAP;
 209         info.si_errno = 0;
 210         info.si_code  = TRAP_BRKPT;
 211         info.si_addr  = (void __user *)instruction_pointer(regs);
 212
 213         force_sig_info(SIGTRAP, &info, tsk);
 214 }
 215
 216 static int break_trap(struct pt_regs *regs, unsigned int instr)
 217 {
 218         ptrace_break(current, regs);
 219         return 0;
 220 }
 221
 222 static struct undef_hook arm_break_hook = {
 223         .instr_mask     = 0x0fffffff,
 224         .instr_val      = 0x07f001f0,
 225         .cpsr_mask      = PSR_T_BIT,
 226         .cpsr_val       = 0,
 227         .fn             = break_trap,
 228 };
 229
 230 static struct undef_hook thumb_break_hook = {
 231         .instr_mask     = 0xffffffff,
 232         .instr_val      = 0x0000de01,
 233         .cpsr_mask      = PSR_T_BIT,
 234         .cpsr_val       = PSR_T_BIT,
 235         .fn             = break_trap,
 236 };
 237
 238 static struct undef_hook thumb2_break_hook = {
 239         .instr_mask     = 0xffffffff,
 240         .instr_val      = 0xf7f0a000,
 241         .cpsr_mask      = PSR_T_BIT,
 242         .cpsr_val       = PSR_T_BIT,
 243         .fn             = break_trap,
 244 };
 245
 246 static int __init ptrace_break_init(void)
 247 {
 248         register_undef_hook(&arm_break_hook);
 249         register_undef_hook(&thumb_break_hook);
 250         register_undef_hook(&thumb2_break_hook);
 251         return 0;
 252 }
 253
 254 core_initcall(ptrace_break_init);
 255
 256 /*
 257  * Read the word at offset "off" into the "struct user".  We
 258  * actually access the pt_regs stored on the kernel stack.
 259  */
 260 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 261                             unsigned long __user *ret)
 262 {
 263         unsigned long tmp;
 264
 265         if (off & 3)
 266                 return -EIO;
 267
 268         tmp = 0;
 269         if (off == PT_TEXT_ADDR)
 270                 tmp = tsk->mm->start_code;
 271         else if (off == PT_DATA_ADDR)
 272                 tmp = tsk->mm->start_data;
 273         else if (off == PT_TEXT_END_ADDR)
 274                 tmp = tsk->mm->end_code;
 275         else if (off < sizeof(struct pt_regs))
 276                 tmp = get_user_reg(tsk, off >> 2);
 277         else if (off >= sizeof(struct user))
 278                 return -EIO;
 279
 280         return put_user(tmp, ret);
 281 }
 282
 283 /*
 284  * Write the word at offset "off" into "struct user".  We
 285  * actually access the pt_regs stored on the kernel stack.
 286  */
 287 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 288                              unsigned long val)
 289 {
 290         if (off & 3 || off >= sizeof(struct user))
 291                 return -EIO;
 292
 293         if (off >= sizeof(struct pt_regs))
 294                 return 0;
 295
 296         return put_user_reg(tsk, off >> 2, val);
 297 }
 298
 299 #ifdef CONFIG_IWMMXT
 300
 301 /*
 302  * Get the child iWMMXt state.
 303  */
 304 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 305 {
 306         struct thread_info *thread = task_thread_info(tsk);
 307
 308         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 309                 return -ENODATA;
 310         iwmmxt_task_disable(thread);  /* force it to ram */
 311         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 312                 ? -EFAULT : 0;
 313 }
 314
 315 /*
 316  * Set the child iWMMXt state.
 317  */
 318 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 319 {
 320         struct thread_info *thread = task_thread_info(tsk);
 321
 322         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 323                 return -EACCES;
 324         iwmmxt_task_release(thread);  /* force a reload */
 325         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 326                 ? -EFAULT : 0;
 327 }
 328
 329 #endif
 330
 331 #ifdef CONFIG_CRUNCH
 332 /*
 333  * Get the child Crunch state.
 334  */
 335 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 336 {
 337         struct thread_info *thread = task_thread_info(tsk);
 338
 339         crunch_task_disable(thread);  /* force it to ram */
 340         return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 341                 ? -EFAULT : 0;
 342 }
 343
 344 /*
 345  * Set the child Crunch state.
 346  */
 347 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 348 {
 349         struct thread_info *thread = task_thread_info(tsk);
 350
 351         crunch_task_release(thread);  /* force a reload */
 352         return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 353                 ? -EFAULT : 0;
 354 }
 355 #endif
 356
 357 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 358 /*
 359  * Convert a virtual register number into an index for a thread_info
 360  * breakpoint array. Breakpoints are identified using positive numbers
 361  * whilst watchpoints are negative. The registers are laid out as pairs
 362  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 363  * Register 0 is reserved for describing resource information.
 364  */
 365 static int ptrace_hbp_num_to_idx(long num)
 366 {
 367         if (num < 0)
 368                 num = (ARM_MAX_BRP << 1) - num;
 369         return (num - 1) >> 1;
 370 }
 371
 372 /*
 373  * Returns the virtual register number for the address of the
 374  * breakpoint at index idx.
 375  */
 376 static long ptrace_hbp_idx_to_num(int idx)
 377 {
 378         long mid = ARM_MAX_BRP << 1;
 379         long num = (idx << 1) + 1;
 380         return num > mid ? mid - num : num;
 381 }
 382
 383 /*
 384  * Handle hitting a HW-breakpoint.
 385  */
 386 static void ptrace_hbptriggered(struct perf_event *bp,
 387                                      struct perf_sample_data *data,
 388                                      struct pt_regs *regs)
 389 {
 390         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 391         long num;
 392         int i;
 393         siginfo_t info;
 394
 395         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 396                 if (current->thread.debug.hbp[i] == bp)
 397                         break;
 398
 399         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 400
 401         info.si_signo   = SIGTRAP;
 402         info.si_errno   = (int)num;
 403         info.si_code    = TRAP_HWBKPT;
 404         info.si_addr    = (void __user *)(bkpt->trigger);
 405
 406         force_sig_info(SIGTRAP, &info, current);
 407 }
 408
 409 /*
 410  * Set ptrace breakpoint pointers to zero for this task.
 411  * This is required in order to prevent child processes from unregistering
 412  * breakpoints held by their parent.
 413  */
 414 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 415 {
 416         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 417 }
 418
 419 /*
 420  * Unregister breakpoints from this task and reset the pointers in
 421  * the thread_struct.
 422  */
 423 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 424 {
 425         int i;
 426         struct thread_struct *t = &tsk->thread;
 427
 428         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 429                 if (t->debug.hbp[i]) {
 430                         unregister_hw_breakpoint(t->debug.hbp[i]);
 431                         t->debug.hbp[i] = NULL;
 432                 }
 433         }
 434 }
 435
 436 static u32 ptrace_get_hbp_resource_info(void)
 437 {
 438         u8 num_brps, num_wrps, debug_arch, wp_len;
 439         u32 reg = 0;
 440
 441         num_brps        = hw_breakpoint_slots(TYPE_INST);
 442         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 443         debug_arch      = arch_get_debug_arch();
 444         wp_len          = arch_get_max_wp_len();
 445
 446         reg             |= debug_arch;
 447         reg             <<= 8;
 448         reg             |= wp_len;
 449         reg             <<= 8;
 450         reg             |= num_wrps;
 451         reg             <<= 8;
 452         reg             |= num_brps;
 453
 454         return reg;
 455 }
 456
 457 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 458 {
 459         struct perf_event_attr attr;
 460
 461         ptrace_breakpoint_init(&attr);
 462
 463         /* Initialise fields to sane defaults. */
 464         attr.bp_addr    = 0;
 465         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 466         attr.bp_type    = type;
 467         attr.disabled   = 1;
 468
 469         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 470                                            tsk);
 471 }
 472
 473 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 474                              unsigned long  __user *data)
 475 {
 476         u32 reg;
 477         int idx, ret = 0;
 478         struct perf_event *bp;
 479         struct arch_hw_breakpoint_ctrl arch_ctrl;
 480
 481         if (num == 0) {
 482                 reg = ptrace_get_hbp_resource_info();
 483         } else {
 484                 idx = ptrace_hbp_num_to_idx(num);
 485                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 486                         ret = -EINVAL;
 487                         goto out;
 488                 }
 489
 490                 bp = tsk->thread.debug.hbp[idx];
 491                 if (!bp) {
 492                         reg = 0;
 493                         goto put;
 494                 }
 495
 496                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 497
 498                 /*
 499                  * Fix up the len because we may have adjusted it
 500                  * to compensate for an unaligned address.
 501                  */
 502                 while (!(arch_ctrl.len & 0x1))
 503                         arch_ctrl.len >>= 1;
 504
 505                 if (num & 0x1)
 506                         reg = bp->attr.bp_addr;
 507                 else
 508                         reg = encode_ctrl_reg(arch_ctrl);
 509         }
 510
 511 put:
 512         if (put_user(reg, data))
 513                 ret = -EFAULT;
 514
 515 out:
 516         return ret;
 517 }
 518
 519 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 520                              unsigned long __user *data)
 521 {
 522         int idx, gen_len, gen_type, implied_type, ret = 0;
 523         u32 user_val;
 524         struct perf_event *bp;
 525         struct arch_hw_breakpoint_ctrl ctrl;
 526         struct perf_event_attr attr;
 527
 528         if (num == 0)
 529                 goto out;
 530         else if (num < 0)
 531                 implied_type = HW_BREAKPOINT_RW;
 532         else
 533                 implied_type = HW_BREAKPOINT_X;
 534
 535         idx = ptrace_hbp_num_to_idx(num);
 536         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 537                 ret = -EINVAL;
 538                 goto out;
 539         }
 540
 541         if (get_user(user_val, data)) {
 542                 ret = -EFAULT;
 543                 goto out;
 544         }
 545
 546         bp = tsk->thread.debug.hbp[idx];
 547         if (!bp) {
 548                 bp = ptrace_hbp_create(tsk, implied_type);
 549                 if (IS_ERR(bp)) {
 550                         ret = PTR_ERR(bp);
 551                         goto out;
 552                 }
 553                 tsk->thread.debug.hbp[idx] = bp;
 554         }
 555
 556         attr = bp->attr;
 557
 558         if (num & 0x1) {
 559                 /* Address */
 560                 attr.bp_addr    = user_val;
 561         } else {
 562                 /* Control */
 563                 decode_ctrl_reg(user_val, &ctrl);
 564                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 565                 if (ret)
 566                         goto out;
 567
 568                 if ((gen_type & implied_type) != gen_type) {
 569                         ret = -EINVAL;
 570                         goto out;
 571                 }
 572
 573                 attr.bp_len     = gen_len;
 574                 attr.bp_type    = gen_type;
 575                 attr.disabled   = !ctrl.enabled;
 576         }
 577
 578         ret = modify_user_hw_breakpoint(bp, &attr);
 579 out:
 580         return ret;
 581 }
 582 #endif
 583
 584 /* regset get/set implementations */
 585
 586 static int gpr_get(struct task_struct *target,
 587                    const struct user_regset *regset,
 588                    unsigned int pos, unsigned int count,
 589                    void *kbuf, void __user *ubuf)
 590 {
 591         struct pt_regs *regs = task_pt_regs(target);
 592
 593         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 594                                    regs,
 595                                    0, sizeof(*regs));
 596 }
 597
 598 static int gpr_set(struct task_struct *target,
 599                    const struct user_regset *regset,
 600                    unsigned int pos, unsigned int count,
 601                    const void *kbuf, const void __user *ubuf)
 602 {
 603         int ret;
 604         struct pt_regs newregs = *task_pt_regs(target);
 605
 606         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 607                                  &newregs,
 608                                  0, sizeof(newregs));
 609         if (ret)
 610                 return ret;
 611
 612         if (!valid_user_regs(&newregs))
 613                 return -EINVAL;
 614
 615         *task_pt_regs(target) = newregs;
 616         return 0;
 617 }
 618
 619 static int fpa_get(struct task_struct *target,
 620                    const struct user_regset *regset,
 621                    unsigned int pos, unsigned int count,
 622                    void *kbuf, void __user *ubuf)
 623 {
 624         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 625                                    &task_thread_info(target)->fpstate,
 626                                    0, sizeof(struct user_fp));
 627 }
 628
 629 static int fpa_set(struct task_struct *target,
 630                    const struct user_regset *regset,
 631                    unsigned int pos, unsigned int count,
 632                    const void *kbuf, const void __user *ubuf)
 633 {
 634         struct thread_info *thread = task_thread_info(target);
 635
 636         thread->used_cp[1] = thread->used_cp[2] = 1;
 637
 638         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 639                 &thread->fpstate,
 640                 0, sizeof(struct user_fp));
 641 }
 642
 643 #ifdef CONFIG_VFP
 644 /*
 645  * VFP register get/set implementations.
 646  *
 647  * With respect to the kernel, struct user_fp is divided into three chunks:
 648  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 649  *      These are transferred to/from the real registers in the task's
 650  *      vfp_hard_struct.  The number of registers depends on the kernel
 651  *      configuration.
 652  *
 653  * 16 or 0 fake VFP registers (d16-d31 or empty)
 654  *      i.e., the user_vfp structure has space for 32 registers even if
 655  *      the kernel doesn't have them all.
 656  *
 657  *      vfp_get() reads this chunk as zero where applicable
 658  *      vfp_set() ignores this chunk
 659  *
 660  * 1 word for the FPSCR
 661  *
 662  * The bounds-checking logic built into user_regset_copyout and friends
 663  * means that we can make a simple sequence of calls to map the relevant data
 664  * to/from the specified slice of the user regset structure.
 665  */
 666 static int vfp_get(struct task_struct *target,
 667                    const struct user_regset *regset,
 668                    unsigned int pos, unsigned int count,
 669                    void *kbuf, void __user *ubuf)
 670 {
 671         int ret;
 672         struct thread_info *thread = task_thread_info(target);
 673         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 674         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 675         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 676
 677         vfp_sync_hwstate(thread);
 678
 679         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 680                                   &vfp->fpregs,
 681                                   user_fpregs_offset,
 682                                   user_fpregs_offset + sizeof(vfp->fpregs));
 683         if (ret)
 684                 return ret;
 685
 686         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 687                                        user_fpregs_offset + sizeof(vfp->fpregs),
 688                                        user_fpscr_offset);
 689         if (ret)
 690                 return ret;
 691
 692         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 693                                    &vfp->fpscr,
 694                                    user_fpscr_offset,
 695                                    user_fpscr_offset + sizeof(vfp->fpscr));
 696 }
 697
 698 /*
 699  * For vfp_set() a read-modify-write is done on the VFP registers,
 700  * in order to avoid writing back a half-modified set of registers on
 701  * failure.
 702  */
 703 static int vfp_set(struct task_struct *target,
 704                           const struct user_regset *regset,
 705                           unsigned int pos, unsigned int count,
 706                           const void *kbuf, const void __user *ubuf)
 707 {
 708         int ret;
 709         struct thread_info *thread = task_thread_info(target);
 710         struct vfp_hard_struct new_vfp;
 711         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 712         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 713
 714         vfp_sync_hwstate(thread);
 715         new_vfp = thread->vfpstate.hard;
 716
 717         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 718                                   &new_vfp.fpregs,
 719                                   user_fpregs_offset,
 720                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 721         if (ret)
 722                 return ret;
 723
 724         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 725                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 726                                 user_fpscr_offset);
 727         if (ret)
 728                 return ret;
 729
 730         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 731                                  &new_vfp.fpscr,
 732                                  user_fpscr_offset,
 733                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 734         if (ret)
 735                 return ret;
 736
 737         thread->vfpstate.hard = new_vfp;
 738         vfp_flush_hwstate(thread);
 739
 740         return 0;
 741 }
 742 #endif /* CONFIG_VFP */
 743
 744 enum arm_regset {
 745         REGSET_GPR,
 746         REGSET_FPR,
 747 #ifdef CONFIG_VFP
 748         REGSET_VFP,
 749 #endif
 750 };
 751
 752 static const struct user_regset arm_regsets[] = {
 753         [REGSET_GPR] = {
 754                 .core_note_type = NT_PRSTATUS,
 755                 .n = ELF_NGREG,
 756                 .size = sizeof(u32),
 757                 .align = sizeof(u32),
 758                 .get = gpr_get,
 759                 .set = gpr_set
 760         },
 761         [REGSET_FPR] = {
 762                 /*
 763                  * For the FPA regs in fpstate, the real fields are a mixture
 764                  * of sizes, so pretend that the registers are word-sized:
 765                  */
 766                 .core_note_type = NT_PRFPREG,
 767                 .n = sizeof(struct user_fp) / sizeof(u32),
 768                 .size = sizeof(u32),
 769                 .align = sizeof(u32),
 770                 .get = fpa_get,
 771                 .set = fpa_set
 772         },
 773 #ifdef CONFIG_VFP
 774         [REGSET_VFP] = {
 775                 /*
 776                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 777                  * a single word dangling at the end of struct user_vfp:
 778                  */
 779                 .core_note_type = NT_ARM_VFP,
 780                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 781                 .size = sizeof(u32),
 782                 .align = sizeof(u32),
 783                 .get = vfp_get,
 784                 .set = vfp_set
 785         },
 786 #endif /* CONFIG_VFP */
 787 };
 788
 789 static const struct user_regset_view user_arm_view = {
 790         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 791         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 792 };
 793
 794 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 795 {
 796         return &user_arm_view;
 797 }
 798
 799 long arch_ptrace(struct task_struct *child, long request,
 800                  unsigned long addr, unsigned long data)
 801 {
 802         int ret;
 803         unsigned long __user *datap = (unsigned long __user *) data;
 804
 805         switch (request) {
 806                 case PTRACE_PEEKUSR:
 807                         ret = ptrace_read_user(child, addr, datap);
 808                         break;
 809
 810                 case PTRACE_POKEUSR:
 811                         ret = ptrace_write_user(child, addr, data);
 812                         break;
 813
 814                 case PTRACE_GETREGS:
 815                         ret = copy_regset_to_user(child,
 816                                                   &user_arm_view, REGSET_GPR,
 817                                                   0, sizeof(struct pt_regs),
 818                                                   datap);
 819                         break;
 820
 821                 case PTRACE_SETREGS:
 822                         ret = copy_regset_from_user(child,
 823                                                     &user_arm_view, REGSET_GPR,
 824                                                     0, sizeof(struct pt_regs),
 825                                                     datap);
 826                         break;
 827
 828                 case PTRACE_GETFPREGS:
 829                         ret = copy_regset_to_user(child,
 830                                                   &user_arm_view, REGSET_FPR,
 831                                                   0, sizeof(union fp_state),
 832                                                   datap);
 833                         break;
 834
 835                 case PTRACE_SETFPREGS:
 836                         ret = copy_regset_from_user(child,
 837                                                     &user_arm_view, REGSET_FPR,
 838                                                     0, sizeof(union fp_state),
 839                                                     datap);
 840                         break;
 841
 842 #ifdef CONFIG_IWMMXT
 843                 case PTRACE_GETWMMXREGS:
 844                         ret = ptrace_getwmmxregs(child, datap);
 845                         break;
 846
 847                 case PTRACE_SETWMMXREGS:
 848                         ret = ptrace_setwmmxregs(child, datap);
 849                         break;
 850 #endif
 851
 852                 case PTRACE_GET_THREAD_AREA:
 853                         ret = put_user(task_thread_info(child)->tp_value[0],
 854                                        datap);
 855                         break;
 856
 857                 case PTRACE_SET_SYSCALL:
 858                         task_thread_info(child)->syscall = data;
 859                         ret = 0;
 860                         break;
 861
 862 #ifdef CONFIG_CRUNCH
 863                 case PTRACE_GETCRUNCHREGS:
 864                         ret = ptrace_getcrunchregs(child, datap);
 865                         break;
 866
 867                 case PTRACE_SETCRUNCHREGS:
 868                         ret = ptrace_setcrunchregs(child, datap);
 869                         break;
 870 #endif
 871
 872 #ifdef CONFIG_VFP
 873                 case PTRACE_GETVFPREGS:
 874                         ret = copy_regset_to_user(child,
 875                                                   &user_arm_view, REGSET_VFP,
 876                                                   0, ARM_VFPREGS_SIZE,
 877                                                   datap);
 878                         break;
 879
 880                 case PTRACE_SETVFPREGS:
 881                         ret = copy_regset_from_user(child,
 882                                                     &user_arm_view, REGSET_VFP,
 883                                                     0, ARM_VFPREGS_SIZE,
 884                                                     datap);
 885                         break;
 886 #endif
 887
 888 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 889                 case PTRACE_GETHBPREGS:
 890                         ret = ptrace_gethbpregs(child, addr,
 891                                                 (unsigned long __user *)data);
 892                         break;
 893                 case PTRACE_SETHBPREGS:
 894                         ret = ptrace_sethbpregs(child, addr,
 895                                                 (unsigned long __user *)data);
 896                         break;
 897 #endif
 898
 899                 default:
 900                         ret = ptrace_request(child, request, addr, data);
 901                         break;
 902         }
 903
 904         return ret;
 905 }
 906
 907 enum ptrace_syscall_dir {
 908         PTRACE_SYSCALL_ENTER = 0,
 909         PTRACE_SYSCALL_EXIT,
 910 };
 911
 912 static void tracehook_report_syscall(struct pt_regs *regs,
 913                                     enum ptrace_syscall_dir dir)
 914 {
 915         unsigned long ip;
 916
 917         /*
 918          * IP is used to denote syscall entry/exit:
 919          * IP = 0 -> entry, =1 -> exit
 920          */
 921         ip = regs->ARM_ip;
 922         regs->ARM_ip = dir;
 923
 924         if (dir == PTRACE_SYSCALL_EXIT)
 925                 tracehook_report_syscall_exit(regs, 0);
 926         else if (tracehook_report_syscall_entry(regs))
 927                 current_thread_info()->syscall = -1;
 928
 929         regs->ARM_ip = ip;
 930 }
 931
 932 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 933 {
 934         current_thread_info()->syscall = scno;
 935
 936         if (test_thread_flag(TIF_SYSCALL_TRACE))
 937                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 938
 939         /* Do seccomp after ptrace; syscall may have changed. */
 940 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 941         if (secure_computing(NULL) == -1)
 942                 return -1;
 943 #else
 944         /* XXX: remove this once OABI gets fixed */
 945         secure_computing_strict(current_thread_info()->syscall);
 946 #endif
 947
 948         /* Tracer or seccomp may have changed syscall. */
 949         scno = current_thread_info()->syscall;
 950
 951         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 952                 trace_sys_enter(regs, scno);
 953
 954         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 955                             regs->ARM_r3);
 956
 957         return scno;
 958 }
 959
 960 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 961 {
 962         /*
 963          * Audit the syscall before anything else, as a debugger may
 964          * come in and change the current registers.
 965          */
 966         audit_syscall_exit(regs);
 967
 968         /*
 969          * Note that we haven't updated the ->syscall field for the
 970          * current thread. This isn't a problem because it will have
 971          * been set on syscall entry and there hasn't been an opportunity
 972          * for a PTRACE_SET_SYSCALL since then.
 973          */
 974         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 975                 trace_sys_exit(regs, regs_return_value(regs));
 976
 977         if (test_thread_flag(TIF_SYSCALL_TRACE))
 978                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 979 }