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         clear_siginfo(&info);
 209         info.si_signo = SIGTRAP;
 210         info.si_errno = 0;
 211         info.si_code  = TRAP_BRKPT;
 212         info.si_addr  = (void __user *)instruction_pointer(regs);
 213
 214         force_sig_info(SIGTRAP, &info, tsk);
 215 }
 216
 217 static int break_trap(struct pt_regs *regs, unsigned int instr)
 218 {
 219         ptrace_break(current, regs);
 220         return 0;
 221 }
 222
 223 static struct undef_hook arm_break_hook = {
 224         .instr_mask     = 0x0fffffff,
 225         .instr_val      = 0x07f001f0,
 226         .cpsr_mask      = PSR_T_BIT,
 227         .cpsr_val       = 0,
 228         .fn             = break_trap,
 229 };
 230
 231 static struct undef_hook thumb_break_hook = {
 232         .instr_mask     = 0xffff,
 233         .instr_val      = 0xde01,
 234         .cpsr_mask      = PSR_T_BIT,
 235         .cpsr_val       = PSR_T_BIT,
 236         .fn             = break_trap,
 237 };
 238
 239 static struct undef_hook thumb2_break_hook = {
 240         .instr_mask     = 0xffffffff,
 241         .instr_val      = 0xf7f0a000,
 242         .cpsr_mask      = PSR_T_BIT,
 243         .cpsr_val       = PSR_T_BIT,
 244         .fn             = break_trap,
 245 };
 246
 247 static int __init ptrace_break_init(void)
 248 {
 249         register_undef_hook(&arm_break_hook);
 250         register_undef_hook(&thumb_break_hook);
 251         register_undef_hook(&thumb2_break_hook);
 252         return 0;
 253 }
 254
 255 core_initcall(ptrace_break_init);
 256
 257 /*
 258  * Read the word at offset "off" into the "struct user".  We
 259  * actually access the pt_regs stored on the kernel stack.
 260  */
 261 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 262                             unsigned long __user *ret)
 263 {
 264         unsigned long tmp;
 265
 266         if (off & 3)
 267                 return -EIO;
 268
 269         tmp = 0;
 270         if (off == PT_TEXT_ADDR)
 271                 tmp = tsk->mm->start_code;
 272         else if (off == PT_DATA_ADDR)
 273                 tmp = tsk->mm->start_data;
 274         else if (off == PT_TEXT_END_ADDR)
 275                 tmp = tsk->mm->end_code;
 276         else if (off < sizeof(struct pt_regs))
 277                 tmp = get_user_reg(tsk, off >> 2);
 278         else if (off >= sizeof(struct user))
 279                 return -EIO;
 280
 281         return put_user(tmp, ret);
 282 }
 283
 284 /*
 285  * Write the word at offset "off" into "struct user".  We
 286  * actually access the pt_regs stored on the kernel stack.
 287  */
 288 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 289                              unsigned long val)
 290 {
 291         if (off & 3 || off >= sizeof(struct user))
 292                 return -EIO;
 293
 294         if (off >= sizeof(struct pt_regs))
 295                 return 0;
 296
 297         return put_user_reg(tsk, off >> 2, val);
 298 }
 299
 300 #ifdef CONFIG_IWMMXT
 301
 302 /*
 303  * Get the child iWMMXt state.
 304  */
 305 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 306 {
 307         struct thread_info *thread = task_thread_info(tsk);
 308
 309         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 310                 return -ENODATA;
 311         iwmmxt_task_disable(thread);  /* force it to ram */
 312         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 313                 ? -EFAULT : 0;
 314 }
 315
 316 /*
 317  * Set the child iWMMXt state.
 318  */
 319 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 320 {
 321         struct thread_info *thread = task_thread_info(tsk);
 322
 323         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 324                 return -EACCES;
 325         iwmmxt_task_release(thread);  /* force a reload */
 326         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 327                 ? -EFAULT : 0;
 328 }
 329
 330 #endif
 331
 332 #ifdef CONFIG_CRUNCH
 333 /*
 334  * Get the child Crunch state.
 335  */
 336 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 337 {
 338         struct thread_info *thread = task_thread_info(tsk);
 339
 340         crunch_task_disable(thread);  /* force it to ram */
 341         return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 342                 ? -EFAULT : 0;
 343 }
 344
 345 /*
 346  * Set the child Crunch state.
 347  */
 348 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 349 {
 350         struct thread_info *thread = task_thread_info(tsk);
 351
 352         crunch_task_release(thread);  /* force a reload */
 353         return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 354                 ? -EFAULT : 0;
 355 }
 356 #endif
 357
 358 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 359 /*
 360  * Convert a virtual register number into an index for a thread_info
 361  * breakpoint array. Breakpoints are identified using positive numbers
 362  * whilst watchpoints are negative. The registers are laid out as pairs
 363  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 364  * Register 0 is reserved for describing resource information.
 365  */
 366 static int ptrace_hbp_num_to_idx(long num)
 367 {
 368         if (num < 0)
 369                 num = (ARM_MAX_BRP << 1) - num;
 370         return (num - 1) >> 1;
 371 }
 372
 373 /*
 374  * Returns the virtual register number for the address of the
 375  * breakpoint at index idx.
 376  */
 377 static long ptrace_hbp_idx_to_num(int idx)
 378 {
 379         long mid = ARM_MAX_BRP << 1;
 380         long num = (idx << 1) + 1;
 381         return num > mid ? mid - num : num;
 382 }
 383
 384 /*
 385  * Handle hitting a HW-breakpoint.
 386  */
 387 static void ptrace_hbptriggered(struct perf_event *bp,
 388                                      struct perf_sample_data *data,
 389                                      struct pt_regs *regs)
 390 {
 391         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 392         long num;
 393         int i;
 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         force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 402 }
 403
 404 /*
 405  * Set ptrace breakpoint pointers to zero for this task.
 406  * This is required in order to prevent child processes from unregistering
 407  * breakpoints held by their parent.
 408  */
 409 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 410 {
 411         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 412 }
 413
 414 /*
 415  * Unregister breakpoints from this task and reset the pointers in
 416  * the thread_struct.
 417  */
 418 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 419 {
 420         int i;
 421         struct thread_struct *t = &tsk->thread;
 422
 423         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 424                 if (t->debug.hbp[i]) {
 425                         unregister_hw_breakpoint(t->debug.hbp[i]);
 426                         t->debug.hbp[i] = NULL;
 427                 }
 428         }
 429 }
 430
 431 static u32 ptrace_get_hbp_resource_info(void)
 432 {
 433         u8 num_brps, num_wrps, debug_arch, wp_len;
 434         u32 reg = 0;
 435
 436         num_brps        = hw_breakpoint_slots(TYPE_INST);
 437         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 438         debug_arch      = arch_get_debug_arch();
 439         wp_len          = arch_get_max_wp_len();
 440
 441         reg             |= debug_arch;
 442         reg             <<= 8;
 443         reg             |= wp_len;
 444         reg             <<= 8;
 445         reg             |= num_wrps;
 446         reg             <<= 8;
 447         reg             |= num_brps;
 448
 449         return reg;
 450 }
 451
 452 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 453 {
 454         struct perf_event_attr attr;
 455
 456         ptrace_breakpoint_init(&attr);
 457
 458         /* Initialise fields to sane defaults. */
 459         attr.bp_addr    = 0;
 460         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 461         attr.bp_type    = type;
 462         attr.disabled   = 1;
 463
 464         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 465                                            tsk);
 466 }
 467
 468 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 469                              unsigned long  __user *data)
 470 {
 471         u32 reg;
 472         int idx, ret = 0;
 473         struct perf_event *bp;
 474         struct arch_hw_breakpoint_ctrl arch_ctrl;
 475
 476         if (num == 0) {
 477                 reg = ptrace_get_hbp_resource_info();
 478         } else {
 479                 idx = ptrace_hbp_num_to_idx(num);
 480                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 481                         ret = -EINVAL;
 482                         goto out;
 483                 }
 484
 485                 bp = tsk->thread.debug.hbp[idx];
 486                 if (!bp) {
 487                         reg = 0;
 488                         goto put;
 489                 }
 490
 491                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 492
 493                 /*
 494                  * Fix up the len because we may have adjusted it
 495                  * to compensate for an unaligned address.
 496                  */
 497                 while (!(arch_ctrl.len & 0x1))
 498                         arch_ctrl.len >>= 1;
 499
 500                 if (num & 0x1)
 501                         reg = bp->attr.bp_addr;
 502                 else
 503                         reg = encode_ctrl_reg(arch_ctrl);
 504         }
 505
 506 put:
 507         if (put_user(reg, data))
 508                 ret = -EFAULT;
 509
 510 out:
 511         return ret;
 512 }
 513
 514 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 515                              unsigned long __user *data)
 516 {
 517         int idx, gen_len, gen_type, implied_type, ret = 0;
 518         u32 user_val;
 519         struct perf_event *bp;
 520         struct arch_hw_breakpoint_ctrl ctrl;
 521         struct perf_event_attr attr;
 522
 523         if (num == 0)
 524                 goto out;
 525         else if (num < 0)
 526                 implied_type = HW_BREAKPOINT_RW;
 527         else
 528                 implied_type = HW_BREAKPOINT_X;
 529
 530         idx = ptrace_hbp_num_to_idx(num);
 531         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 532                 ret = -EINVAL;
 533                 goto out;
 534         }
 535
 536         if (get_user(user_val, data)) {
 537                 ret = -EFAULT;
 538                 goto out;
 539         }
 540
 541         bp = tsk->thread.debug.hbp[idx];
 542         if (!bp) {
 543                 bp = ptrace_hbp_create(tsk, implied_type);
 544                 if (IS_ERR(bp)) {
 545                         ret = PTR_ERR(bp);
 546                         goto out;
 547                 }
 548                 tsk->thread.debug.hbp[idx] = bp;
 549         }
 550
 551         attr = bp->attr;
 552
 553         if (num & 0x1) {
 554                 /* Address */
 555                 attr.bp_addr    = user_val;
 556         } else {
 557                 /* Control */
 558                 decode_ctrl_reg(user_val, &ctrl);
 559                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 560                 if (ret)
 561                         goto out;
 562
 563                 if ((gen_type & implied_type) != gen_type) {
 564                         ret = -EINVAL;
 565                         goto out;
 566                 }
 567
 568                 attr.bp_len     = gen_len;
 569                 attr.bp_type    = gen_type;
 570                 attr.disabled   = !ctrl.enabled;
 571         }
 572
 573         ret = modify_user_hw_breakpoint(bp, &attr);
 574 out:
 575         return ret;
 576 }
 577 #endif
 578
 579 /* regset get/set implementations */
 580
 581 static int gpr_get(struct task_struct *target,
 582                    const struct user_regset *regset,
 583                    unsigned int pos, unsigned int count,
 584                    void *kbuf, void __user *ubuf)
 585 {
 586         struct pt_regs *regs = task_pt_regs(target);
 587
 588         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 589                                    regs,
 590                                    0, sizeof(*regs));
 591 }
 592
 593 static int gpr_set(struct task_struct *target,
 594                    const struct user_regset *regset,
 595                    unsigned int pos, unsigned int count,
 596                    const void *kbuf, const void __user *ubuf)
 597 {
 598         int ret;
 599         struct pt_regs newregs = *task_pt_regs(target);
 600
 601         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 602                                  &newregs,
 603                                  0, sizeof(newregs));
 604         if (ret)
 605                 return ret;
 606
 607         if (!valid_user_regs(&newregs))
 608                 return -EINVAL;
 609
 610         *task_pt_regs(target) = newregs;
 611         return 0;
 612 }
 613
 614 static int fpa_get(struct task_struct *target,
 615                    const struct user_regset *regset,
 616                    unsigned int pos, unsigned int count,
 617                    void *kbuf, void __user *ubuf)
 618 {
 619         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 620                                    &task_thread_info(target)->fpstate,
 621                                    0, sizeof(struct user_fp));
 622 }
 623
 624 static int fpa_set(struct task_struct *target,
 625                    const struct user_regset *regset,
 626                    unsigned int pos, unsigned int count,
 627                    const void *kbuf, const void __user *ubuf)
 628 {
 629         struct thread_info *thread = task_thread_info(target);
 630
 631         thread->used_cp[1] = thread->used_cp[2] = 1;
 632
 633         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 634                 &thread->fpstate,
 635                 0, sizeof(struct user_fp));
 636 }
 637
 638 #ifdef CONFIG_VFP
 639 /*
 640  * VFP register get/set implementations.
 641  *
 642  * With respect to the kernel, struct user_fp is divided into three chunks:
 643  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 644  *      These are transferred to/from the real registers in the task's
 645  *      vfp_hard_struct.  The number of registers depends on the kernel
 646  *      configuration.
 647  *
 648  * 16 or 0 fake VFP registers (d16-d31 or empty)
 649  *      i.e., the user_vfp structure has space for 32 registers even if
 650  *      the kernel doesn't have them all.
 651  *
 652  *      vfp_get() reads this chunk as zero where applicable
 653  *      vfp_set() ignores this chunk
 654  *
 655  * 1 word for the FPSCR
 656  *
 657  * The bounds-checking logic built into user_regset_copyout and friends
 658  * means that we can make a simple sequence of calls to map the relevant data
 659  * to/from the specified slice of the user regset structure.
 660  */
 661 static int vfp_get(struct task_struct *target,
 662                    const struct user_regset *regset,
 663                    unsigned int pos, unsigned int count,
 664                    void *kbuf, void __user *ubuf)
 665 {
 666         int ret;
 667         struct thread_info *thread = task_thread_info(target);
 668         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 669         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 670         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 671
 672         vfp_sync_hwstate(thread);
 673
 674         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 675                                   &vfp->fpregs,
 676                                   user_fpregs_offset,
 677                                   user_fpregs_offset + sizeof(vfp->fpregs));
 678         if (ret)
 679                 return ret;
 680
 681         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 682                                        user_fpregs_offset + sizeof(vfp->fpregs),
 683                                        user_fpscr_offset);
 684         if (ret)
 685                 return ret;
 686
 687         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 688                                    &vfp->fpscr,
 689                                    user_fpscr_offset,
 690                                    user_fpscr_offset + sizeof(vfp->fpscr));
 691 }
 692
 693 /*
 694  * For vfp_set() a read-modify-write is done on the VFP registers,
 695  * in order to avoid writing back a half-modified set of registers on
 696  * failure.
 697  */
 698 static int vfp_set(struct task_struct *target,
 699                           const struct user_regset *regset,
 700                           unsigned int pos, unsigned int count,
 701                           const void *kbuf, const void __user *ubuf)
 702 {
 703         int ret;
 704         struct thread_info *thread = task_thread_info(target);
 705         struct vfp_hard_struct new_vfp;
 706         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 707         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 708
 709         vfp_sync_hwstate(thread);
 710         new_vfp = thread->vfpstate.hard;
 711
 712         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 713                                   &new_vfp.fpregs,
 714                                   user_fpregs_offset,
 715                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 716         if (ret)
 717                 return ret;
 718
 719         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 720                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 721                                 user_fpscr_offset);
 722         if (ret)
 723                 return ret;
 724
 725         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 726                                  &new_vfp.fpscr,
 727                                  user_fpscr_offset,
 728                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 729         if (ret)
 730                 return ret;
 731
 732         thread->vfpstate.hard = new_vfp;
 733         vfp_flush_hwstate(thread);
 734
 735         return 0;
 736 }
 737 #endif /* CONFIG_VFP */
 738
 739 enum arm_regset {
 740         REGSET_GPR,
 741         REGSET_FPR,
 742 #ifdef CONFIG_VFP
 743         REGSET_VFP,
 744 #endif
 745 };
 746
 747 static const struct user_regset arm_regsets[] = {
 748         [REGSET_GPR] = {
 749                 .core_note_type = NT_PRSTATUS,
 750                 .n = ELF_NGREG,
 751                 .size = sizeof(u32),
 752                 .align = sizeof(u32),
 753                 .get = gpr_get,
 754                 .set = gpr_set
 755         },
 756         [REGSET_FPR] = {
 757                 /*
 758                  * For the FPA regs in fpstate, the real fields are a mixture
 759                  * of sizes, so pretend that the registers are word-sized:
 760                  */
 761                 .core_note_type = NT_PRFPREG,
 762                 .n = sizeof(struct user_fp) / sizeof(u32),
 763                 .size = sizeof(u32),
 764                 .align = sizeof(u32),
 765                 .get = fpa_get,
 766                 .set = fpa_set
 767         },
 768 #ifdef CONFIG_VFP
 769         [REGSET_VFP] = {
 770                 /*
 771                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 772                  * a single word dangling at the end of struct user_vfp:
 773                  */
 774                 .core_note_type = NT_ARM_VFP,
 775                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 776                 .size = sizeof(u32),
 777                 .align = sizeof(u32),
 778                 .get = vfp_get,
 779                 .set = vfp_set
 780         },
 781 #endif /* CONFIG_VFP */
 782 };
 783
 784 static const struct user_regset_view user_arm_view = {
 785         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 786         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 787 };
 788
 789 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 790 {
 791         return &user_arm_view;
 792 }
 793
 794 long arch_ptrace(struct task_struct *child, long request,
 795                  unsigned long addr, unsigned long data)
 796 {
 797         int ret;
 798         unsigned long __user *datap = (unsigned long __user *) data;
 799
 800         switch (request) {
 801                 case PTRACE_PEEKUSR:
 802                         ret = ptrace_read_user(child, addr, datap);
 803                         break;
 804
 805                 case PTRACE_POKEUSR:
 806                         ret = ptrace_write_user(child, addr, data);
 807                         break;
 808
 809                 case PTRACE_GETREGS:
 810                         ret = copy_regset_to_user(child,
 811                                                   &user_arm_view, REGSET_GPR,
 812                                                   0, sizeof(struct pt_regs),
 813                                                   datap);
 814                         break;
 815
 816                 case PTRACE_SETREGS:
 817                         ret = copy_regset_from_user(child,
 818                                                     &user_arm_view, REGSET_GPR,
 819                                                     0, sizeof(struct pt_regs),
 820                                                     datap);
 821                         break;
 822
 823                 case PTRACE_GETFPREGS:
 824                         ret = copy_regset_to_user(child,
 825                                                   &user_arm_view, REGSET_FPR,
 826                                                   0, sizeof(union fp_state),
 827                                                   datap);
 828                         break;
 829
 830                 case PTRACE_SETFPREGS:
 831                         ret = copy_regset_from_user(child,
 832                                                     &user_arm_view, REGSET_FPR,
 833                                                     0, sizeof(union fp_state),
 834                                                     datap);
 835                         break;
 836
 837 #ifdef CONFIG_IWMMXT
 838                 case PTRACE_GETWMMXREGS:
 839                         ret = ptrace_getwmmxregs(child, datap);
 840                         break;
 841
 842                 case PTRACE_SETWMMXREGS:
 843                         ret = ptrace_setwmmxregs(child, datap);
 844                         break;
 845 #endif
 846
 847                 case PTRACE_GET_THREAD_AREA:
 848                         ret = put_user(task_thread_info(child)->tp_value[0],
 849                                        datap);
 850                         break;
 851
 852                 case PTRACE_SET_SYSCALL:
 853                         task_thread_info(child)->syscall = data;
 854                         ret = 0;
 855                         break;
 856
 857 #ifdef CONFIG_CRUNCH
 858                 case PTRACE_GETCRUNCHREGS:
 859                         ret = ptrace_getcrunchregs(child, datap);
 860                         break;
 861
 862                 case PTRACE_SETCRUNCHREGS:
 863                         ret = ptrace_setcrunchregs(child, datap);
 864                         break;
 865 #endif
 866
 867 #ifdef CONFIG_VFP
 868                 case PTRACE_GETVFPREGS:
 869                         ret = copy_regset_to_user(child,
 870                                                   &user_arm_view, REGSET_VFP,
 871                                                   0, ARM_VFPREGS_SIZE,
 872                                                   datap);
 873                         break;
 874
 875                 case PTRACE_SETVFPREGS:
 876                         ret = copy_regset_from_user(child,
 877                                                     &user_arm_view, REGSET_VFP,
 878                                                     0, ARM_VFPREGS_SIZE,
 879                                                     datap);
 880                         break;
 881 #endif
 882
 883 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 884                 case PTRACE_GETHBPREGS:
 885                         ret = ptrace_gethbpregs(child, addr,
 886                                                 (unsigned long __user *)data);
 887                         break;
 888                 case PTRACE_SETHBPREGS:
 889                         ret = ptrace_sethbpregs(child, addr,
 890                                                 (unsigned long __user *)data);
 891                         break;
 892 #endif
 893
 894                 default:
 895                         ret = ptrace_request(child, request, addr, data);
 896                         break;
 897         }
 898
 899         return ret;
 900 }
 901
 902 enum ptrace_syscall_dir {
 903         PTRACE_SYSCALL_ENTER = 0,
 904         PTRACE_SYSCALL_EXIT,
 905 };
 906
 907 static void tracehook_report_syscall(struct pt_regs *regs,
 908                                     enum ptrace_syscall_dir dir)
 909 {
 910         unsigned long ip;
 911
 912         /*
 913          * IP is used to denote syscall entry/exit:
 914          * IP = 0 -> entry, =1 -> exit
 915          */
 916         ip = regs->ARM_ip;
 917         regs->ARM_ip = dir;
 918
 919         if (dir == PTRACE_SYSCALL_EXIT)
 920                 tracehook_report_syscall_exit(regs, 0);
 921         else if (tracehook_report_syscall_entry(regs))
 922                 current_thread_info()->syscall = -1;
 923
 924         regs->ARM_ip = ip;
 925 }
 926
 927 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 928 {
 929         current_thread_info()->syscall = scno;
 930
 931         if (test_thread_flag(TIF_SYSCALL_TRACE))
 932                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 933
 934         /* Do seccomp after ptrace; syscall may have changed. */
 935 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 936         if (secure_computing(NULL) == -1)
 937                 return -1;
 938 #else
 939         /* XXX: remove this once OABI gets fixed */
 940         secure_computing_strict(current_thread_info()->syscall);
 941 #endif
 942
 943         /* Tracer or seccomp may have changed syscall. */
 944         scno = current_thread_info()->syscall;
 945
 946         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 947                 trace_sys_enter(regs, scno);
 948
 949         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 950                             regs->ARM_r3);
 951
 952         return scno;
 953 }
 954
 955 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 956 {
 957         /*
 958          * Audit the syscall before anything else, as a debugger may
 959          * come in and change the current registers.
 960          */
 961         audit_syscall_exit(regs);
 962
 963         /*
 964          * Note that we haven't updated the ->syscall field for the
 965          * current thread. This isn't a problem because it will have
 966          * been set on syscall entry and there hasn't been an opportunity
 967          * for a PTRACE_SET_SYSCALL since then.
 968          */
 969         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 970                 trace_sys_exit(regs, regs_return_value(regs));
 971
 972         if (test_thread_flag(TIF_SYSCALL_TRACE))
 973                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 974 }