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     = 0xffff,
 232         .instr_val      = 0xde01,
 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
 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         force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 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 = *task_pt_regs(target);
 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         thread->vfpstate.hard = new_vfp;
 732         vfp_flush_hwstate(thread);
 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[0],
 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                         ret = ptrace_gethbpregs(child, addr,
 885                                                 (unsigned long __user *)data);
 886                         break;
 887                 case PTRACE_SETHBPREGS:
 888                         ret = ptrace_sethbpregs(child, addr,
 889                                                 (unsigned long __user *)data);
 890                         break;
 891 #endif
 892
 893                 default:
 894                         ret = ptrace_request(child, request, addr, data);
 895                         break;
 896         }
 897
 898         return ret;
 899 }
 900
 901 enum ptrace_syscall_dir {
 902         PTRACE_SYSCALL_ENTER = 0,
 903         PTRACE_SYSCALL_EXIT,
 904 };
 905
 906 static void tracehook_report_syscall(struct pt_regs *regs,
 907                                     enum ptrace_syscall_dir dir)
 908 {
 909         unsigned long ip;
 910
 911         /*
 912          * IP is used to denote syscall entry/exit:
 913          * IP = 0 -> entry, =1 -> exit
 914          */
 915         ip = regs->ARM_ip;
 916         regs->ARM_ip = dir;
 917
 918         if (dir == PTRACE_SYSCALL_EXIT)
 919                 tracehook_report_syscall_exit(regs, 0);
 920         else if (tracehook_report_syscall_entry(regs))
 921                 current_thread_info()->syscall = -1;
 922
 923         regs->ARM_ip = ip;
 924 }
 925
 926 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 927 {
 928         current_thread_info()->syscall = scno;
 929
 930         if (test_thread_flag(TIF_SYSCALL_TRACE))
 931                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 932
 933         /* Do seccomp after ptrace; syscall may have changed. */
 934 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 935         if (secure_computing(NULL) == -1)
 936                 return -1;
 937 #else
 938         /* XXX: remove this once OABI gets fixed */
 939         secure_computing_strict(current_thread_info()->syscall);
 940 #endif
 941
 942         /* Tracer or seccomp may have changed syscall. */
 943         scno = current_thread_info()->syscall;
 944
 945         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 946                 trace_sys_enter(regs, scno);
 947
 948         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 949                             regs->ARM_r3);
 950
 951         return scno;
 952 }
 953
 954 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 955 {
 956         /*
 957          * Audit the syscall before anything else, as a debugger may
 958          * come in and change the current registers.
 959          */
 960         audit_syscall_exit(regs);
 961
 962         /*
 963          * Note that we haven't updated the ->syscall field for the
 964          * current thread. This isn't a problem because it will have
 965          * been set on syscall entry and there hasn't been an opportunity
 966          * for a PTRACE_SET_SYSCALL since then.
 967          */
 968         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 969                 trace_sys_exit(regs, regs_return_value(regs));
 970
 971         if (test_thread_flag(TIF_SYSCALL_TRACE))
 972                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 973 }