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         force_sig_fault(SIGTRAP, TRAP_BRKPT,
 207                         (void __user *)instruction_pointer(regs), tsk);
 208 }
 209
 210 static int break_trap(struct pt_regs *regs, unsigned int instr)
 211 {
 212         ptrace_break(current, regs);
 213         return 0;
 214 }
 215
 216 static struct undef_hook arm_break_hook = {
 217         .instr_mask     = 0x0fffffff,
 218         .instr_val      = 0x07f001f0,
 219         .cpsr_mask      = PSR_T_BIT,
 220         .cpsr_val       = 0,
 221         .fn             = break_trap,
 222 };
 223
 224 static struct undef_hook thumb_break_hook = {
 225         .instr_mask     = 0xffff,
 226         .instr_val      = 0xde01,
 227         .cpsr_mask      = PSR_T_BIT,
 228         .cpsr_val       = PSR_T_BIT,
 229         .fn             = break_trap,
 230 };
 231
 232 static struct undef_hook thumb2_break_hook = {
 233         .instr_mask     = 0xffffffff,
 234         .instr_val      = 0xf7f0a000,
 235         .cpsr_mask      = PSR_T_BIT,
 236         .cpsr_val       = PSR_T_BIT,
 237         .fn             = break_trap,
 238 };
 239
 240 static int __init ptrace_break_init(void)
 241 {
 242         register_undef_hook(&arm_break_hook);
 243         register_undef_hook(&thumb_break_hook);
 244         register_undef_hook(&thumb2_break_hook);
 245         return 0;
 246 }
 247
 248 core_initcall(ptrace_break_init);
 249
 250 /*
 251  * Read the word at offset "off" into the "struct user".  We
 252  * actually access the pt_regs stored on the kernel stack.
 253  */
 254 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 255                             unsigned long __user *ret)
 256 {
 257         unsigned long tmp;
 258
 259         if (off & 3)
 260                 return -EIO;
 261
 262         tmp = 0;
 263         if (off == PT_TEXT_ADDR)
 264                 tmp = tsk->mm->start_code;
 265         else if (off == PT_DATA_ADDR)
 266                 tmp = tsk->mm->start_data;
 267         else if (off == PT_TEXT_END_ADDR)
 268                 tmp = tsk->mm->end_code;
 269         else if (off < sizeof(struct pt_regs))
 270                 tmp = get_user_reg(tsk, off >> 2);
 271         else if (off >= sizeof(struct user))
 272                 return -EIO;
 273
 274         return put_user(tmp, ret);
 275 }
 276
 277 /*
 278  * Write the word at offset "off" into "struct user".  We
 279  * actually access the pt_regs stored on the kernel stack.
 280  */
 281 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 282                              unsigned long val)
 283 {
 284         if (off & 3 || off >= sizeof(struct user))
 285                 return -EIO;
 286
 287         if (off >= sizeof(struct pt_regs))
 288                 return 0;
 289
 290         return put_user_reg(tsk, off >> 2, val);
 291 }
 292
 293 #ifdef CONFIG_IWMMXT
 294
 295 /*
 296  * Get the child iWMMXt state.
 297  */
 298 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 299 {
 300         struct thread_info *thread = task_thread_info(tsk);
 301
 302         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 303                 return -ENODATA;
 304         iwmmxt_task_disable(thread);  /* force it to ram */
 305         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 306                 ? -EFAULT : 0;
 307 }
 308
 309 /*
 310  * Set the child iWMMXt state.
 311  */
 312 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 313 {
 314         struct thread_info *thread = task_thread_info(tsk);
 315
 316         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 317                 return -EACCES;
 318         iwmmxt_task_release(thread);  /* force a reload */
 319         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 320                 ? -EFAULT : 0;
 321 }
 322
 323 #endif
 324
 325 #ifdef CONFIG_CRUNCH
 326 /*
 327  * Get the child Crunch state.
 328  */
 329 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 330 {
 331         struct thread_info *thread = task_thread_info(tsk);
 332
 333         crunch_task_disable(thread);  /* force it to ram */
 334         return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 335                 ? -EFAULT : 0;
 336 }
 337
 338 /*
 339  * Set the child Crunch state.
 340  */
 341 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 342 {
 343         struct thread_info *thread = task_thread_info(tsk);
 344
 345         crunch_task_release(thread);  /* force a reload */
 346         return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 347                 ? -EFAULT : 0;
 348 }
 349 #endif
 350
 351 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 352 /*
 353  * Convert a virtual register number into an index for a thread_info
 354  * breakpoint array. Breakpoints are identified using positive numbers
 355  * whilst watchpoints are negative. The registers are laid out as pairs
 356  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 357  * Register 0 is reserved for describing resource information.
 358  */
 359 static int ptrace_hbp_num_to_idx(long num)
 360 {
 361         if (num < 0)
 362                 num = (ARM_MAX_BRP << 1) - num;
 363         return (num - 1) >> 1;
 364 }
 365
 366 /*
 367  * Returns the virtual register number for the address of the
 368  * breakpoint at index idx.
 369  */
 370 static long ptrace_hbp_idx_to_num(int idx)
 371 {
 372         long mid = ARM_MAX_BRP << 1;
 373         long num = (idx << 1) + 1;
 374         return num > mid ? mid - num : num;
 375 }
 376
 377 /*
 378  * Handle hitting a HW-breakpoint.
 379  */
 380 static void ptrace_hbptriggered(struct perf_event *bp,
 381                                      struct perf_sample_data *data,
 382                                      struct pt_regs *regs)
 383 {
 384         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 385         long num;
 386         int i;
 387
 388         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 389                 if (current->thread.debug.hbp[i] == bp)
 390                         break;
 391
 392         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 393
 394         force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 395 }
 396
 397 /*
 398  * Set ptrace breakpoint pointers to zero for this task.
 399  * This is required in order to prevent child processes from unregistering
 400  * breakpoints held by their parent.
 401  */
 402 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 403 {
 404         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 405 }
 406
 407 /*
 408  * Unregister breakpoints from this task and reset the pointers in
 409  * the thread_struct.
 410  */
 411 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 412 {
 413         int i;
 414         struct thread_struct *t = &tsk->thread;
 415
 416         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 417                 if (t->debug.hbp[i]) {
 418                         unregister_hw_breakpoint(t->debug.hbp[i]);
 419                         t->debug.hbp[i] = NULL;
 420                 }
 421         }
 422 }
 423
 424 static u32 ptrace_get_hbp_resource_info(void)
 425 {
 426         u8 num_brps, num_wrps, debug_arch, wp_len;
 427         u32 reg = 0;
 428
 429         num_brps        = hw_breakpoint_slots(TYPE_INST);
 430         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 431         debug_arch      = arch_get_debug_arch();
 432         wp_len          = arch_get_max_wp_len();
 433
 434         reg             |= debug_arch;
 435         reg             <<= 8;
 436         reg             |= wp_len;
 437         reg             <<= 8;
 438         reg             |= num_wrps;
 439         reg             <<= 8;
 440         reg             |= num_brps;
 441
 442         return reg;
 443 }
 444
 445 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 446 {
 447         struct perf_event_attr attr;
 448
 449         ptrace_breakpoint_init(&attr);
 450
 451         /* Initialise fields to sane defaults. */
 452         attr.bp_addr    = 0;
 453         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 454         attr.bp_type    = type;
 455         attr.disabled   = 1;
 456
 457         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 458                                            tsk);
 459 }
 460
 461 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 462                              unsigned long  __user *data)
 463 {
 464         u32 reg;
 465         int idx, ret = 0;
 466         struct perf_event *bp;
 467         struct arch_hw_breakpoint_ctrl arch_ctrl;
 468
 469         if (num == 0) {
 470                 reg = ptrace_get_hbp_resource_info();
 471         } else {
 472                 idx = ptrace_hbp_num_to_idx(num);
 473                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 474                         ret = -EINVAL;
 475                         goto out;
 476                 }
 477
 478                 bp = tsk->thread.debug.hbp[idx];
 479                 if (!bp) {
 480                         reg = 0;
 481                         goto put;
 482                 }
 483
 484                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 485
 486                 /*
 487                  * Fix up the len because we may have adjusted it
 488                  * to compensate for an unaligned address.
 489                  */
 490                 while (!(arch_ctrl.len & 0x1))
 491                         arch_ctrl.len >>= 1;
 492
 493                 if (num & 0x1)
 494                         reg = bp->attr.bp_addr;
 495                 else
 496                         reg = encode_ctrl_reg(arch_ctrl);
 497         }
 498
 499 put:
 500         if (put_user(reg, data))
 501                 ret = -EFAULT;
 502
 503 out:
 504         return ret;
 505 }
 506
 507 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 508                              unsigned long __user *data)
 509 {
 510         int idx, gen_len, gen_type, implied_type, ret = 0;
 511         u32 user_val;
 512         struct perf_event *bp;
 513         struct arch_hw_breakpoint_ctrl ctrl;
 514         struct perf_event_attr attr;
 515
 516         if (num == 0)
 517                 goto out;
 518         else if (num < 0)
 519                 implied_type = HW_BREAKPOINT_RW;
 520         else
 521                 implied_type = HW_BREAKPOINT_X;
 522
 523         idx = ptrace_hbp_num_to_idx(num);
 524         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 525                 ret = -EINVAL;
 526                 goto out;
 527         }
 528
 529         if (get_user(user_val, data)) {
 530                 ret = -EFAULT;
 531                 goto out;
 532         }
 533
 534         bp = tsk->thread.debug.hbp[idx];
 535         if (!bp) {
 536                 bp = ptrace_hbp_create(tsk, implied_type);
 537                 if (IS_ERR(bp)) {
 538                         ret = PTR_ERR(bp);
 539                         goto out;
 540                 }
 541                 tsk->thread.debug.hbp[idx] = bp;
 542         }
 543
 544         attr = bp->attr;
 545
 546         if (num & 0x1) {
 547                 /* Address */
 548                 attr.bp_addr    = user_val;
 549         } else {
 550                 /* Control */
 551                 decode_ctrl_reg(user_val, &ctrl);
 552                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 553                 if (ret)
 554                         goto out;
 555
 556                 if ((gen_type & implied_type) != gen_type) {
 557                         ret = -EINVAL;
 558                         goto out;
 559                 }
 560
 561                 attr.bp_len     = gen_len;
 562                 attr.bp_type    = gen_type;
 563                 attr.disabled   = !ctrl.enabled;
 564         }
 565
 566         ret = modify_user_hw_breakpoint(bp, &attr);
 567 out:
 568         return ret;
 569 }
 570 #endif
 571
 572 /* regset get/set implementations */
 573
 574 static int gpr_get(struct task_struct *target,
 575                    const struct user_regset *regset,
 576                    unsigned int pos, unsigned int count,
 577                    void *kbuf, void __user *ubuf)
 578 {
 579         struct pt_regs *regs = task_pt_regs(target);
 580
 581         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 582                                    regs,
 583                                    0, sizeof(*regs));
 584 }
 585
 586 static int gpr_set(struct task_struct *target,
 587                    const struct user_regset *regset,
 588                    unsigned int pos, unsigned int count,
 589                    const void *kbuf, const void __user *ubuf)
 590 {
 591         int ret;
 592         struct pt_regs newregs = *task_pt_regs(target);
 593
 594         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 595                                  &newregs,
 596                                  0, sizeof(newregs));
 597         if (ret)
 598                 return ret;
 599
 600         if (!valid_user_regs(&newregs))
 601                 return -EINVAL;
 602
 603         *task_pt_regs(target) = newregs;
 604         return 0;
 605 }
 606
 607 static int fpa_get(struct task_struct *target,
 608                    const struct user_regset *regset,
 609                    unsigned int pos, unsigned int count,
 610                    void *kbuf, void __user *ubuf)
 611 {
 612         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 613                                    &task_thread_info(target)->fpstate,
 614                                    0, sizeof(struct user_fp));
 615 }
 616
 617 static int fpa_set(struct task_struct *target,
 618                    const struct user_regset *regset,
 619                    unsigned int pos, unsigned int count,
 620                    const void *kbuf, const void __user *ubuf)
 621 {
 622         struct thread_info *thread = task_thread_info(target);
 623
 624         thread->used_cp[1] = thread->used_cp[2] = 1;
 625
 626         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 627                 &thread->fpstate,
 628                 0, sizeof(struct user_fp));
 629 }
 630
 631 #ifdef CONFIG_VFP
 632 /*
 633  * VFP register get/set implementations.
 634  *
 635  * With respect to the kernel, struct user_fp is divided into three chunks:
 636  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 637  *      These are transferred to/from the real registers in the task's
 638  *      vfp_hard_struct.  The number of registers depends on the kernel
 639  *      configuration.
 640  *
 641  * 16 or 0 fake VFP registers (d16-d31 or empty)
 642  *      i.e., the user_vfp structure has space for 32 registers even if
 643  *      the kernel doesn't have them all.
 644  *
 645  *      vfp_get() reads this chunk as zero where applicable
 646  *      vfp_set() ignores this chunk
 647  *
 648  * 1 word for the FPSCR
 649  *
 650  * The bounds-checking logic built into user_regset_copyout and friends
 651  * means that we can make a simple sequence of calls to map the relevant data
 652  * to/from the specified slice of the user regset structure.
 653  */
 654 static int vfp_get(struct task_struct *target,
 655                    const struct user_regset *regset,
 656                    unsigned int pos, unsigned int count,
 657                    void *kbuf, void __user *ubuf)
 658 {
 659         int ret;
 660         struct thread_info *thread = task_thread_info(target);
 661         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 662         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 663         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 664
 665         vfp_sync_hwstate(thread);
 666
 667         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 668                                   &vfp->fpregs,
 669                                   user_fpregs_offset,
 670                                   user_fpregs_offset + sizeof(vfp->fpregs));
 671         if (ret)
 672                 return ret;
 673
 674         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 675                                        user_fpregs_offset + sizeof(vfp->fpregs),
 676                                        user_fpscr_offset);
 677         if (ret)
 678                 return ret;
 679
 680         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 681                                    &vfp->fpscr,
 682                                    user_fpscr_offset,
 683                                    user_fpscr_offset + sizeof(vfp->fpscr));
 684 }
 685
 686 /*
 687  * For vfp_set() a read-modify-write is done on the VFP registers,
 688  * in order to avoid writing back a half-modified set of registers on
 689  * failure.
 690  */
 691 static int vfp_set(struct task_struct *target,
 692                           const struct user_regset *regset,
 693                           unsigned int pos, unsigned int count,
 694                           const void *kbuf, const void __user *ubuf)
 695 {
 696         int ret;
 697         struct thread_info *thread = task_thread_info(target);
 698         struct vfp_hard_struct new_vfp;
 699         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 700         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 701
 702         vfp_sync_hwstate(thread);
 703         new_vfp = thread->vfpstate.hard;
 704
 705         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 706                                   &new_vfp.fpregs,
 707                                   user_fpregs_offset,
 708                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 709         if (ret)
 710                 return ret;
 711
 712         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 713                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 714                                 user_fpscr_offset);
 715         if (ret)
 716                 return ret;
 717
 718         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 719                                  &new_vfp.fpscr,
 720                                  user_fpscr_offset,
 721                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 722         if (ret)
 723                 return ret;
 724
 725         thread->vfpstate.hard = new_vfp;
 726         vfp_flush_hwstate(thread);
 727
 728         return 0;
 729 }
 730 #endif /* CONFIG_VFP */
 731
 732 enum arm_regset {
 733         REGSET_GPR,
 734         REGSET_FPR,
 735 #ifdef CONFIG_VFP
 736         REGSET_VFP,
 737 #endif
 738 };
 739
 740 static const struct user_regset arm_regsets[] = {
 741         [REGSET_GPR] = {
 742                 .core_note_type = NT_PRSTATUS,
 743                 .n = ELF_NGREG,
 744                 .size = sizeof(u32),
 745                 .align = sizeof(u32),
 746                 .get = gpr_get,
 747                 .set = gpr_set
 748         },
 749         [REGSET_FPR] = {
 750                 /*
 751                  * For the FPA regs in fpstate, the real fields are a mixture
 752                  * of sizes, so pretend that the registers are word-sized:
 753                  */
 754                 .core_note_type = NT_PRFPREG,
 755                 .n = sizeof(struct user_fp) / sizeof(u32),
 756                 .size = sizeof(u32),
 757                 .align = sizeof(u32),
 758                 .get = fpa_get,
 759                 .set = fpa_set
 760         },
 761 #ifdef CONFIG_VFP
 762         [REGSET_VFP] = {
 763                 /*
 764                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 765                  * a single word dangling at the end of struct user_vfp:
 766                  */
 767                 .core_note_type = NT_ARM_VFP,
 768                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 769                 .size = sizeof(u32),
 770                 .align = sizeof(u32),
 771                 .get = vfp_get,
 772                 .set = vfp_set
 773         },
 774 #endif /* CONFIG_VFP */
 775 };
 776
 777 static const struct user_regset_view user_arm_view = {
 778         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 779         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 780 };
 781
 782 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 783 {
 784         return &user_arm_view;
 785 }
 786
 787 long arch_ptrace(struct task_struct *child, long request,
 788                  unsigned long addr, unsigned long data)
 789 {
 790         int ret;
 791         unsigned long __user *datap = (unsigned long __user *) data;
 792
 793         switch (request) {
 794                 case PTRACE_PEEKUSR:
 795                         ret = ptrace_read_user(child, addr, datap);
 796                         break;
 797
 798                 case PTRACE_POKEUSR:
 799                         ret = ptrace_write_user(child, addr, data);
 800                         break;
 801
 802                 case PTRACE_GETREGS:
 803                         ret = copy_regset_to_user(child,
 804                                                   &user_arm_view, REGSET_GPR,
 805                                                   0, sizeof(struct pt_regs),
 806                                                   datap);
 807                         break;
 808
 809                 case PTRACE_SETREGS:
 810                         ret = copy_regset_from_user(child,
 811                                                     &user_arm_view, REGSET_GPR,
 812                                                     0, sizeof(struct pt_regs),
 813                                                     datap);
 814                         break;
 815
 816                 case PTRACE_GETFPREGS:
 817                         ret = copy_regset_to_user(child,
 818                                                   &user_arm_view, REGSET_FPR,
 819                                                   0, sizeof(union fp_state),
 820                                                   datap);
 821                         break;
 822
 823                 case PTRACE_SETFPREGS:
 824                         ret = copy_regset_from_user(child,
 825                                                     &user_arm_view, REGSET_FPR,
 826                                                     0, sizeof(union fp_state),
 827                                                     datap);
 828                         break;
 829
 830 #ifdef CONFIG_IWMMXT
 831                 case PTRACE_GETWMMXREGS:
 832                         ret = ptrace_getwmmxregs(child, datap);
 833                         break;
 834
 835                 case PTRACE_SETWMMXREGS:
 836                         ret = ptrace_setwmmxregs(child, datap);
 837                         break;
 838 #endif
 839
 840                 case PTRACE_GET_THREAD_AREA:
 841                         ret = put_user(task_thread_info(child)->tp_value[0],
 842                                        datap);
 843                         break;
 844
 845                 case PTRACE_SET_SYSCALL:
 846                         task_thread_info(child)->syscall = data;
 847                         ret = 0;
 848                         break;
 849
 850 #ifdef CONFIG_CRUNCH
 851                 case PTRACE_GETCRUNCHREGS:
 852                         ret = ptrace_getcrunchregs(child, datap);
 853                         break;
 854
 855                 case PTRACE_SETCRUNCHREGS:
 856                         ret = ptrace_setcrunchregs(child, datap);
 857                         break;
 858 #endif
 859
 860 #ifdef CONFIG_VFP
 861                 case PTRACE_GETVFPREGS:
 862                         ret = copy_regset_to_user(child,
 863                                                   &user_arm_view, REGSET_VFP,
 864                                                   0, ARM_VFPREGS_SIZE,
 865                                                   datap);
 866                         break;
 867
 868                 case PTRACE_SETVFPREGS:
 869                         ret = copy_regset_from_user(child,
 870                                                     &user_arm_view, REGSET_VFP,
 871                                                     0, ARM_VFPREGS_SIZE,
 872                                                     datap);
 873                         break;
 874 #endif
 875
 876 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 877                 case PTRACE_GETHBPREGS:
 878                         ret = ptrace_gethbpregs(child, addr,
 879                                                 (unsigned long __user *)data);
 880                         break;
 881                 case PTRACE_SETHBPREGS:
 882                         ret = ptrace_sethbpregs(child, addr,
 883                                                 (unsigned long __user *)data);
 884                         break;
 885 #endif
 886
 887                 default:
 888                         ret = ptrace_request(child, request, addr, data);
 889                         break;
 890         }
 891
 892         return ret;
 893 }
 894
 895 enum ptrace_syscall_dir {
 896         PTRACE_SYSCALL_ENTER = 0,
 897         PTRACE_SYSCALL_EXIT,
 898 };
 899
 900 static void tracehook_report_syscall(struct pt_regs *regs,
 901                                     enum ptrace_syscall_dir dir)
 902 {
 903         unsigned long ip;
 904
 905         /*
 906          * IP is used to denote syscall entry/exit:
 907          * IP = 0 -> entry, =1 -> exit
 908          */
 909         ip = regs->ARM_ip;
 910         regs->ARM_ip = dir;
 911
 912         if (dir == PTRACE_SYSCALL_EXIT)
 913                 tracehook_report_syscall_exit(regs, 0);
 914         else if (tracehook_report_syscall_entry(regs))
 915                 current_thread_info()->syscall = -1;
 916
 917         regs->ARM_ip = ip;
 918 }
 919
 920 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 921 {
 922         current_thread_info()->syscall = scno;
 923
 924         if (test_thread_flag(TIF_SYSCALL_TRACE))
 925                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 926
 927         /* Do seccomp after ptrace; syscall may have changed. */
 928 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 929         if (secure_computing(NULL) == -1)
 930                 return -1;
 931 #else
 932         /* XXX: remove this once OABI gets fixed */
 933         secure_computing_strict(current_thread_info()->syscall);
 934 #endif
 935
 936         /* Tracer or seccomp may have changed syscall. */
 937         scno = current_thread_info()->syscall;
 938
 939         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 940                 trace_sys_enter(regs, scno);
 941
 942         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 943                             regs->ARM_r3);
 944
 945         return scno;
 946 }
 947
 948 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 949 {
 950         /*
 951          * Audit the syscall before anything else, as a debugger may
 952          * come in and change the current registers.
 953          */
 954         audit_syscall_exit(regs);
 955
 956         /*
 957          * Note that we haven't updated the ->syscall field for the
 958          * current thread. This isn't a problem because it will have
 959          * been set on syscall entry and there hasn't been an opportunity
 960          * for a PTRACE_SET_SYSCALL since then.
 961          */
 962         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 963                 trace_sys_exit(regs, regs_return_value(regs));
 964
 965         if (test_thread_flag(TIF_SYSCALL_TRACE))
 966                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 967 }