arch/arm/kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/kernel/ptrace.c
   4  *
   5  *  By Ross Biro 1/23/92
   6  * edited by Linus Torvalds
   7  * ARM modifications Copyright (C) 2000 Russell King
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/sched/signal.h>
  11 #include <linux/sched/task_stack.h>
  12 #include <linux/mm.h>
  13 #include <linux/elf.h>
  14 #include <linux/smp.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/user.h>
  17 #include <linux/security.h>
  18 #include <linux/init.h>
  19 #include <linux/signal.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/perf_event.h>
  22 #include <linux/hw_breakpoint.h>
  23 #include <linux/regset.h>
  24 #include <linux/audit.h>
  25 #include <linux/tracehook.h>
  26 #include <linux/unistd.h>
  27
  28 #include <asm/pgtable.h>
  29 #include <asm/traps.h>
  30
  31 #define CREATE_TRACE_POINTS
  32 #include <trace/events/syscalls.h>
  33
  34 #define REG_PC  15
  35 #define REG_PSR 16
  36 /*
  37  * does not yet catch signals sent when the child dies.
  38  * in exit.c or in signal.c.
  39  */
  40
  41 #if 0
  42 /*
  43  * Breakpoint SWI instruction: SWI &9F0001
  44  */
  45 #define BREAKINST_ARM   0xef9f0001
  46 #define BREAKINST_THUMB 0xdf00          /* fill this in later */
  47 #else
  48 /*
  49  * New breakpoints - use an undefined instruction.  The ARM architecture
  50  * reference manual guarantees that the following instruction space
  51  * will produce an undefined instruction exception on all CPUs:
  52  *
  53  *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
  54  *  Thumb: 1101 1110 xxxx xxxx
  55  */
  56 #define BREAKINST_ARM   0xe7f001f0
  57 #define BREAKINST_THUMB 0xde01
  58 #endif
  59
  60 struct pt_regs_offset {
  61         const char *name;
  62         int offset;
  63 };
  64
  65 #define REG_OFFSET_NAME(r) \
  66         {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
  67 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  68
  69 static const struct pt_regs_offset regoffset_table[] = {
  70         REG_OFFSET_NAME(r0),
  71         REG_OFFSET_NAME(r1),
  72         REG_OFFSET_NAME(r2),
  73         REG_OFFSET_NAME(r3),
  74         REG_OFFSET_NAME(r4),
  75         REG_OFFSET_NAME(r5),
  76         REG_OFFSET_NAME(r6),
  77         REG_OFFSET_NAME(r7),
  78         REG_OFFSET_NAME(r8),
  79         REG_OFFSET_NAME(r9),
  80         REG_OFFSET_NAME(r10),
  81         REG_OFFSET_NAME(fp),
  82         REG_OFFSET_NAME(ip),
  83         REG_OFFSET_NAME(sp),
  84         REG_OFFSET_NAME(lr),
  85         REG_OFFSET_NAME(pc),
  86         REG_OFFSET_NAME(cpsr),
  87         REG_OFFSET_NAME(ORIG_r0),
  88         REG_OFFSET_END,
  89 };
  90
  91 /**
  92  * regs_query_register_offset() - query register offset from its name
  93  * @name:       the name of a register
  94  *
  95  * regs_query_register_offset() returns the offset of a register in struct
  96  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
  97  */
  98 int regs_query_register_offset(const char *name)
  99 {
 100         const struct pt_regs_offset *roff;
 101         for (roff = regoffset_table; roff->name != NULL; roff++)
 102                 if (!strcmp(roff->name, name))
 103                         return roff->offset;
 104         return -EINVAL;
 105 }
 106
 107 /**
 108  * regs_query_register_name() - query register name from its offset
 109  * @offset:     the offset of a register in struct pt_regs.
 110  *
 111  * regs_query_register_name() returns the name of a register from its
 112  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 113  */
 114 const char *regs_query_register_name(unsigned int offset)
 115 {
 116         const struct pt_regs_offset *roff;
 117         for (roff = regoffset_table; roff->name != NULL; roff++)
 118                 if (roff->offset == offset)
 119                         return roff->name;
 120         return NULL;
 121 }
 122
 123 /**
 124  * regs_within_kernel_stack() - check the address in the stack
 125  * @regs:      pt_regs which contains kernel stack pointer.
 126  * @addr:      address which is checked.
 127  *
 128  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 129  * If @addr is within the kernel stack, it returns true. If not, returns false.
 130  */
 131 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 132 {
 133         return ((addr & ~(THREAD_SIZE - 1))  ==
 134                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
 135 }
 136
 137 /**
 138  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 139  * @regs:       pt_regs which contains kernel stack pointer.
 140  * @n:          stack entry number.
 141  *
 142  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 143  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 144  * this returns 0.
 145  */
 146 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 147 {
 148         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 149         addr += n;
 150         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 151                 return *addr;
 152         else
 153                 return 0;
 154 }
 155
 156 /*
 157  * this routine will get a word off of the processes privileged stack.
 158  * the offset is how far from the base addr as stored in the THREAD.
 159  * this routine assumes that all the privileged stacks are in our
 160  * data space.
 161  */
 162 static inline long get_user_reg(struct task_struct *task, int offset)
 163 {
 164         return task_pt_regs(task)->uregs[offset];
 165 }
 166
 167 /*
 168  * this routine will put a word on the processes privileged stack.
 169  * the offset is how far from the base addr as stored in the THREAD.
 170  * this routine assumes that all the privileged stacks are in our
 171  * data space.
 172  */
 173 static inline int
 174 put_user_reg(struct task_struct *task, int offset, long data)
 175 {
 176         struct pt_regs newregs, *regs = task_pt_regs(task);
 177         int ret = -EINVAL;
 178
 179         newregs = *regs;
 180         newregs.uregs[offset] = data;
 181
 182         if (valid_user_regs(&newregs)) {
 183                 regs->uregs[offset] = data;
 184                 ret = 0;
 185         }
 186
 187         return ret;
 188 }
 189
 190 /*
 191  * Called by kernel/ptrace.c when detaching..
 192  */
 193 void ptrace_disable(struct task_struct *child)
 194 {
 195         /* Nothing to do. */
 196 }
 197
 198 /*
 199  * Handle hitting a breakpoint.
 200  */
 201 void ptrace_break(struct pt_regs *regs)
 202 {
 203         force_sig_fault(SIGTRAP, TRAP_BRKPT,
 204                         (void __user *)instruction_pointer(regs));
 205 }
 206
 207 static int break_trap(struct pt_regs *regs, unsigned int instr)
 208 {
 209         ptrace_break(regs);
 210         return 0;
 211 }
 212
 213 static struct undef_hook arm_break_hook = {
 214         .instr_mask     = 0x0fffffff,
 215         .instr_val      = 0x07f001f0,
 216         .cpsr_mask      = PSR_T_BIT,
 217         .cpsr_val       = 0,
 218         .fn             = break_trap,
 219 };
 220
 221 static struct undef_hook thumb_break_hook = {
 222         .instr_mask     = 0xffff,
 223         .instr_val      = 0xde01,
 224         .cpsr_mask      = PSR_T_BIT,
 225         .cpsr_val       = PSR_T_BIT,
 226         .fn             = break_trap,
 227 };
 228
 229 static struct undef_hook thumb2_break_hook = {
 230         .instr_mask     = 0xffffffff,
 231         .instr_val      = 0xf7f0a000,
 232         .cpsr_mask      = PSR_T_BIT,
 233         .cpsr_val       = PSR_T_BIT,
 234         .fn             = break_trap,
 235 };
 236
 237 static int __init ptrace_break_init(void)
 238 {
 239         register_undef_hook(&arm_break_hook);
 240         register_undef_hook(&thumb_break_hook);
 241         register_undef_hook(&thumb2_break_hook);
 242         return 0;
 243 }
 244
 245 core_initcall(ptrace_break_init);
 246
 247 /*
 248  * Read the word at offset "off" into the "struct user".  We
 249  * actually access the pt_regs stored on the kernel stack.
 250  */
 251 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
 252                             unsigned long __user *ret)
 253 {
 254         unsigned long tmp;
 255
 256         if (off & 3)
 257                 return -EIO;
 258
 259         tmp = 0;
 260         if (off == PT_TEXT_ADDR)
 261                 tmp = tsk->mm->start_code;
 262         else if (off == PT_DATA_ADDR)
 263                 tmp = tsk->mm->start_data;
 264         else if (off == PT_TEXT_END_ADDR)
 265                 tmp = tsk->mm->end_code;
 266         else if (off < sizeof(struct pt_regs))
 267                 tmp = get_user_reg(tsk, off >> 2);
 268         else if (off >= sizeof(struct user))
 269                 return -EIO;
 270
 271         return put_user(tmp, ret);
 272 }
 273
 274 /*
 275  * Write the word at offset "off" into "struct user".  We
 276  * actually access the pt_regs stored on the kernel stack.
 277  */
 278 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
 279                              unsigned long val)
 280 {
 281         if (off & 3 || off >= sizeof(struct user))
 282                 return -EIO;
 283
 284         if (off >= sizeof(struct pt_regs))
 285                 return 0;
 286
 287         return put_user_reg(tsk, off >> 2, val);
 288 }
 289
 290 #ifdef CONFIG_IWMMXT
 291
 292 /*
 293  * Get the child iWMMXt state.
 294  */
 295 static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
 296 {
 297         struct thread_info *thread = task_thread_info(tsk);
 298
 299         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 300                 return -ENODATA;
 301         iwmmxt_task_disable(thread);  /* force it to ram */
 302         return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
 303                 ? -EFAULT : 0;
 304 }
 305
 306 /*
 307  * Set the child iWMMXt state.
 308  */
 309 static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
 310 {
 311         struct thread_info *thread = task_thread_info(tsk);
 312
 313         if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
 314                 return -EACCES;
 315         iwmmxt_task_release(thread);  /* force a reload */
 316         return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
 317                 ? -EFAULT : 0;
 318 }
 319
 320 #endif
 321
 322 #ifdef CONFIG_CRUNCH
 323 /*
 324  * Get the child Crunch state.
 325  */
 326 static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
 327 {
 328         struct thread_info *thread = task_thread_info(tsk);
 329
 330         crunch_task_disable(thread);  /* force it to ram */
 331         return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
 332                 ? -EFAULT : 0;
 333 }
 334
 335 /*
 336  * Set the child Crunch state.
 337  */
 338 static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
 339 {
 340         struct thread_info *thread = task_thread_info(tsk);
 341
 342         crunch_task_release(thread);  /* force a reload */
 343         return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
 344                 ? -EFAULT : 0;
 345 }
 346 #endif
 347
 348 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 349 /*
 350  * Convert a virtual register number into an index for a thread_info
 351  * breakpoint array. Breakpoints are identified using positive numbers
 352  * whilst watchpoints are negative. The registers are laid out as pairs
 353  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 354  * Register 0 is reserved for describing resource information.
 355  */
 356 static int ptrace_hbp_num_to_idx(long num)
 357 {
 358         if (num < 0)
 359                 num = (ARM_MAX_BRP << 1) - num;
 360         return (num - 1) >> 1;
 361 }
 362
 363 /*
 364  * Returns the virtual register number for the address of the
 365  * breakpoint at index idx.
 366  */
 367 static long ptrace_hbp_idx_to_num(int idx)
 368 {
 369         long mid = ARM_MAX_BRP << 1;
 370         long num = (idx << 1) + 1;
 371         return num > mid ? mid - num : num;
 372 }
 373
 374 /*
 375  * Handle hitting a HW-breakpoint.
 376  */
 377 static void ptrace_hbptriggered(struct perf_event *bp,
 378                                      struct perf_sample_data *data,
 379                                      struct pt_regs *regs)
 380 {
 381         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 382         long num;
 383         int i;
 384
 385         for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
 386                 if (current->thread.debug.hbp[i] == bp)
 387                         break;
 388
 389         num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
 390
 391         force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
 392 }
 393
 394 /*
 395  * Set ptrace breakpoint pointers to zero for this task.
 396  * This is required in order to prevent child processes from unregistering
 397  * breakpoints held by their parent.
 398  */
 399 void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
 400 {
 401         memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
 402 }
 403
 404 /*
 405  * Unregister breakpoints from this task and reset the pointers in
 406  * the thread_struct.
 407  */
 408 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 409 {
 410         int i;
 411         struct thread_struct *t = &tsk->thread;
 412
 413         for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
 414                 if (t->debug.hbp[i]) {
 415                         unregister_hw_breakpoint(t->debug.hbp[i]);
 416                         t->debug.hbp[i] = NULL;
 417                 }
 418         }
 419 }
 420
 421 static u32 ptrace_get_hbp_resource_info(void)
 422 {
 423         u8 num_brps, num_wrps, debug_arch, wp_len;
 424         u32 reg = 0;
 425
 426         num_brps        = hw_breakpoint_slots(TYPE_INST);
 427         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 428         debug_arch      = arch_get_debug_arch();
 429         wp_len          = arch_get_max_wp_len();
 430
 431         reg             |= debug_arch;
 432         reg             <<= 8;
 433         reg             |= wp_len;
 434         reg             <<= 8;
 435         reg             |= num_wrps;
 436         reg             <<= 8;
 437         reg             |= num_brps;
 438
 439         return reg;
 440 }
 441
 442 static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
 443 {
 444         struct perf_event_attr attr;
 445
 446         ptrace_breakpoint_init(&attr);
 447
 448         /* Initialise fields to sane defaults. */
 449         attr.bp_addr    = 0;
 450         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 451         attr.bp_type    = type;
 452         attr.disabled   = 1;
 453
 454         return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
 455                                            tsk);
 456 }
 457
 458 static int ptrace_gethbpregs(struct task_struct *tsk, long num,
 459                              unsigned long  __user *data)
 460 {
 461         u32 reg;
 462         int idx, ret = 0;
 463         struct perf_event *bp;
 464         struct arch_hw_breakpoint_ctrl arch_ctrl;
 465
 466         if (num == 0) {
 467                 reg = ptrace_get_hbp_resource_info();
 468         } else {
 469                 idx = ptrace_hbp_num_to_idx(num);
 470                 if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 471                         ret = -EINVAL;
 472                         goto out;
 473                 }
 474
 475                 bp = tsk->thread.debug.hbp[idx];
 476                 if (!bp) {
 477                         reg = 0;
 478                         goto put;
 479                 }
 480
 481                 arch_ctrl = counter_arch_bp(bp)->ctrl;
 482
 483                 /*
 484                  * Fix up the len because we may have adjusted it
 485                  * to compensate for an unaligned address.
 486                  */
 487                 while (!(arch_ctrl.len & 0x1))
 488                         arch_ctrl.len >>= 1;
 489
 490                 if (num & 0x1)
 491                         reg = bp->attr.bp_addr;
 492                 else
 493                         reg = encode_ctrl_reg(arch_ctrl);
 494         }
 495
 496 put:
 497         if (put_user(reg, data))
 498                 ret = -EFAULT;
 499
 500 out:
 501         return ret;
 502 }
 503
 504 static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 505                              unsigned long __user *data)
 506 {
 507         int idx, gen_len, gen_type, implied_type, ret = 0;
 508         u32 user_val;
 509         struct perf_event *bp;
 510         struct arch_hw_breakpoint_ctrl ctrl;
 511         struct perf_event_attr attr;
 512
 513         if (num == 0)
 514                 goto out;
 515         else if (num < 0)
 516                 implied_type = HW_BREAKPOINT_RW;
 517         else
 518                 implied_type = HW_BREAKPOINT_X;
 519
 520         idx = ptrace_hbp_num_to_idx(num);
 521         if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
 522                 ret = -EINVAL;
 523                 goto out;
 524         }
 525
 526         if (get_user(user_val, data)) {
 527                 ret = -EFAULT;
 528                 goto out;
 529         }
 530
 531         bp = tsk->thread.debug.hbp[idx];
 532         if (!bp) {
 533                 bp = ptrace_hbp_create(tsk, implied_type);
 534                 if (IS_ERR(bp)) {
 535                         ret = PTR_ERR(bp);
 536                         goto out;
 537                 }
 538                 tsk->thread.debug.hbp[idx] = bp;
 539         }
 540
 541         attr = bp->attr;
 542
 543         if (num & 0x1) {
 544                 /* Address */
 545                 attr.bp_addr    = user_val;
 546         } else {
 547                 /* Control */
 548                 decode_ctrl_reg(user_val, &ctrl);
 549                 ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
 550                 if (ret)
 551                         goto out;
 552
 553                 if ((gen_type & implied_type) != gen_type) {
 554                         ret = -EINVAL;
 555                         goto out;
 556                 }
 557
 558                 attr.bp_len     = gen_len;
 559                 attr.bp_type    = gen_type;
 560                 attr.disabled   = !ctrl.enabled;
 561         }
 562
 563         ret = modify_user_hw_breakpoint(bp, &attr);
 564 out:
 565         return ret;
 566 }
 567 #endif
 568
 569 /* regset get/set implementations */
 570
 571 static int gpr_get(struct task_struct *target,
 572                    const struct user_regset *regset,
 573                    unsigned int pos, unsigned int count,
 574                    void *kbuf, void __user *ubuf)
 575 {
 576         struct pt_regs *regs = task_pt_regs(target);
 577
 578         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 579                                    regs,
 580                                    0, sizeof(*regs));
 581 }
 582
 583 static int gpr_set(struct task_struct *target,
 584                    const struct user_regset *regset,
 585                    unsigned int pos, unsigned int count,
 586                    const void *kbuf, const void __user *ubuf)
 587 {
 588         int ret;
 589         struct pt_regs newregs = *task_pt_regs(target);
 590
 591         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 592                                  &newregs,
 593                                  0, sizeof(newregs));
 594         if (ret)
 595                 return ret;
 596
 597         if (!valid_user_regs(&newregs))
 598                 return -EINVAL;
 599
 600         *task_pt_regs(target) = newregs;
 601         return 0;
 602 }
 603
 604 static int fpa_get(struct task_struct *target,
 605                    const struct user_regset *regset,
 606                    unsigned int pos, unsigned int count,
 607                    void *kbuf, void __user *ubuf)
 608 {
 609         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 610                                    &task_thread_info(target)->fpstate,
 611                                    0, sizeof(struct user_fp));
 612 }
 613
 614 static int fpa_set(struct task_struct *target,
 615                    const struct user_regset *regset,
 616                    unsigned int pos, unsigned int count,
 617                    const void *kbuf, const void __user *ubuf)
 618 {
 619         struct thread_info *thread = task_thread_info(target);
 620
 621         thread->used_cp[1] = thread->used_cp[2] = 1;
 622
 623         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 624                 &thread->fpstate,
 625                 0, sizeof(struct user_fp));
 626 }
 627
 628 #ifdef CONFIG_VFP
 629 /*
 630  * VFP register get/set implementations.
 631  *
 632  * With respect to the kernel, struct user_fp is divided into three chunks:
 633  * 16 or 32 real VFP registers (d0-d15 or d0-31)
 634  *      These are transferred to/from the real registers in the task's
 635  *      vfp_hard_struct.  The number of registers depends on the kernel
 636  *      configuration.
 637  *
 638  * 16 or 0 fake VFP registers (d16-d31 or empty)
 639  *      i.e., the user_vfp structure has space for 32 registers even if
 640  *      the kernel doesn't have them all.
 641  *
 642  *      vfp_get() reads this chunk as zero where applicable
 643  *      vfp_set() ignores this chunk
 644  *
 645  * 1 word for the FPSCR
 646  *
 647  * The bounds-checking logic built into user_regset_copyout and friends
 648  * means that we can make a simple sequence of calls to map the relevant data
 649  * to/from the specified slice of the user regset structure.
 650  */
 651 static int vfp_get(struct task_struct *target,
 652                    const struct user_regset *regset,
 653                    unsigned int pos, unsigned int count,
 654                    void *kbuf, void __user *ubuf)
 655 {
 656         int ret;
 657         struct thread_info *thread = task_thread_info(target);
 658         struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
 659         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 660         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 661
 662         vfp_sync_hwstate(thread);
 663
 664         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 665                                   &vfp->fpregs,
 666                                   user_fpregs_offset,
 667                                   user_fpregs_offset + sizeof(vfp->fpregs));
 668         if (ret)
 669                 return ret;
 670
 671         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 672                                        user_fpregs_offset + sizeof(vfp->fpregs),
 673                                        user_fpscr_offset);
 674         if (ret)
 675                 return ret;
 676
 677         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 678                                    &vfp->fpscr,
 679                                    user_fpscr_offset,
 680                                    user_fpscr_offset + sizeof(vfp->fpscr));
 681 }
 682
 683 /*
 684  * For vfp_set() a read-modify-write is done on the VFP registers,
 685  * in order to avoid writing back a half-modified set of registers on
 686  * failure.
 687  */
 688 static int vfp_set(struct task_struct *target,
 689                           const struct user_regset *regset,
 690                           unsigned int pos, unsigned int count,
 691                           const void *kbuf, const void __user *ubuf)
 692 {
 693         int ret;
 694         struct thread_info *thread = task_thread_info(target);
 695         struct vfp_hard_struct new_vfp;
 696         const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 697         const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 698
 699         vfp_sync_hwstate(thread);
 700         new_vfp = thread->vfpstate.hard;
 701
 702         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 703                                   &new_vfp.fpregs,
 704                                   user_fpregs_offset,
 705                                   user_fpregs_offset + sizeof(new_vfp.fpregs));
 706         if (ret)
 707                 return ret;
 708
 709         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 710                                 user_fpregs_offset + sizeof(new_vfp.fpregs),
 711                                 user_fpscr_offset);
 712         if (ret)
 713                 return ret;
 714
 715         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 716                                  &new_vfp.fpscr,
 717                                  user_fpscr_offset,
 718                                  user_fpscr_offset + sizeof(new_vfp.fpscr));
 719         if (ret)
 720                 return ret;
 721
 722         thread->vfpstate.hard = new_vfp;
 723         vfp_flush_hwstate(thread);
 724
 725         return 0;
 726 }
 727 #endif /* CONFIG_VFP */
 728
 729 enum arm_regset {
 730         REGSET_GPR,
 731         REGSET_FPR,
 732 #ifdef CONFIG_VFP
 733         REGSET_VFP,
 734 #endif
 735 };
 736
 737 static const struct user_regset arm_regsets[] = {
 738         [REGSET_GPR] = {
 739                 .core_note_type = NT_PRSTATUS,
 740                 .n = ELF_NGREG,
 741                 .size = sizeof(u32),
 742                 .align = sizeof(u32),
 743                 .get = gpr_get,
 744                 .set = gpr_set
 745         },
 746         [REGSET_FPR] = {
 747                 /*
 748                  * For the FPA regs in fpstate, the real fields are a mixture
 749                  * of sizes, so pretend that the registers are word-sized:
 750                  */
 751                 .core_note_type = NT_PRFPREG,
 752                 .n = sizeof(struct user_fp) / sizeof(u32),
 753                 .size = sizeof(u32),
 754                 .align = sizeof(u32),
 755                 .get = fpa_get,
 756                 .set = fpa_set
 757         },
 758 #ifdef CONFIG_VFP
 759         [REGSET_VFP] = {
 760                 /*
 761                  * Pretend that the VFP regs are word-sized, since the FPSCR is
 762                  * a single word dangling at the end of struct user_vfp:
 763                  */
 764                 .core_note_type = NT_ARM_VFP,
 765                 .n = ARM_VFPREGS_SIZE / sizeof(u32),
 766                 .size = sizeof(u32),
 767                 .align = sizeof(u32),
 768                 .get = vfp_get,
 769                 .set = vfp_set
 770         },
 771 #endif /* CONFIG_VFP */
 772 };
 773
 774 static const struct user_regset_view user_arm_view = {
 775         .name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
 776         .regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
 777 };
 778
 779 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 780 {
 781         return &user_arm_view;
 782 }
 783
 784 long arch_ptrace(struct task_struct *child, long request,
 785                  unsigned long addr, unsigned long data)
 786 {
 787         int ret;
 788         unsigned long __user *datap = (unsigned long __user *) data;
 789
 790         switch (request) {
 791                 case PTRACE_PEEKUSR:
 792                         ret = ptrace_read_user(child, addr, datap);
 793                         break;
 794
 795                 case PTRACE_POKEUSR:
 796                         ret = ptrace_write_user(child, addr, data);
 797                         break;
 798
 799                 case PTRACE_GETREGS:
 800                         ret = copy_regset_to_user(child,
 801                                                   &user_arm_view, REGSET_GPR,
 802                                                   0, sizeof(struct pt_regs),
 803                                                   datap);
 804                         break;
 805
 806                 case PTRACE_SETREGS:
 807                         ret = copy_regset_from_user(child,
 808                                                     &user_arm_view, REGSET_GPR,
 809                                                     0, sizeof(struct pt_regs),
 810                                                     datap);
 811                         break;
 812
 813                 case PTRACE_GETFPREGS:
 814                         ret = copy_regset_to_user(child,
 815                                                   &user_arm_view, REGSET_FPR,
 816                                                   0, sizeof(union fp_state),
 817                                                   datap);
 818                         break;
 819
 820                 case PTRACE_SETFPREGS:
 821                         ret = copy_regset_from_user(child,
 822                                                     &user_arm_view, REGSET_FPR,
 823                                                     0, sizeof(union fp_state),
 824                                                     datap);
 825                         break;
 826
 827 #ifdef CONFIG_IWMMXT
 828                 case PTRACE_GETWMMXREGS:
 829                         ret = ptrace_getwmmxregs(child, datap);
 830                         break;
 831
 832                 case PTRACE_SETWMMXREGS:
 833                         ret = ptrace_setwmmxregs(child, datap);
 834                         break;
 835 #endif
 836
 837                 case PTRACE_GET_THREAD_AREA:
 838                         ret = put_user(task_thread_info(child)->tp_value[0],
 839                                        datap);
 840                         break;
 841
 842                 case PTRACE_SET_SYSCALL:
 843                         task_thread_info(child)->syscall = data;
 844                         ret = 0;
 845                         break;
 846
 847 #ifdef CONFIG_CRUNCH
 848                 case PTRACE_GETCRUNCHREGS:
 849                         ret = ptrace_getcrunchregs(child, datap);
 850                         break;
 851
 852                 case PTRACE_SETCRUNCHREGS:
 853                         ret = ptrace_setcrunchregs(child, datap);
 854                         break;
 855 #endif
 856
 857 #ifdef CONFIG_VFP
 858                 case PTRACE_GETVFPREGS:
 859                         ret = copy_regset_to_user(child,
 860                                                   &user_arm_view, REGSET_VFP,
 861                                                   0, ARM_VFPREGS_SIZE,
 862                                                   datap);
 863                         break;
 864
 865                 case PTRACE_SETVFPREGS:
 866                         ret = copy_regset_from_user(child,
 867                                                     &user_arm_view, REGSET_VFP,
 868                                                     0, ARM_VFPREGS_SIZE,
 869                                                     datap);
 870                         break;
 871 #endif
 872
 873 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 874                 case PTRACE_GETHBPREGS:
 875                         ret = ptrace_gethbpregs(child, addr,
 876                                                 (unsigned long __user *)data);
 877                         break;
 878                 case PTRACE_SETHBPREGS:
 879                         ret = ptrace_sethbpregs(child, addr,
 880                                                 (unsigned long __user *)data);
 881                         break;
 882 #endif
 883
 884                 default:
 885                         ret = ptrace_request(child, request, addr, data);
 886                         break;
 887         }
 888
 889         return ret;
 890 }
 891
 892 enum ptrace_syscall_dir {
 893         PTRACE_SYSCALL_ENTER = 0,
 894         PTRACE_SYSCALL_EXIT,
 895 };
 896
 897 static void tracehook_report_syscall(struct pt_regs *regs,
 898                                     enum ptrace_syscall_dir dir)
 899 {
 900         unsigned long ip;
 901
 902         /*
 903          * IP is used to denote syscall entry/exit:
 904          * IP = 0 -> entry, =1 -> exit
 905          */
 906         ip = regs->ARM_ip;
 907         regs->ARM_ip = dir;
 908
 909         if (dir == PTRACE_SYSCALL_EXIT)
 910                 tracehook_report_syscall_exit(regs, 0);
 911         else if (tracehook_report_syscall_entry(regs))
 912                 current_thread_info()->syscall = -1;
 913
 914         regs->ARM_ip = ip;
 915 }
 916
 917 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 918 {
 919         current_thread_info()->syscall = scno;
 920
 921         if (test_thread_flag(TIF_SYSCALL_TRACE))
 922                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
 923
 924         /* Do seccomp after ptrace; syscall may have changed. */
 925 #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
 926         if (secure_computing(NULL) == -1)
 927                 return -1;
 928 #else
 929         /* XXX: remove this once OABI gets fixed */
 930         secure_computing_strict(current_thread_info()->syscall);
 931 #endif
 932
 933         /* Tracer or seccomp may have changed syscall. */
 934         scno = current_thread_info()->syscall;
 935
 936         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 937                 trace_sys_enter(regs, scno);
 938
 939         audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
 940                             regs->ARM_r3);
 941
 942         return scno;
 943 }
 944
 945 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 946 {
 947         /*
 948          * Audit the syscall before anything else, as a debugger may
 949          * come in and change the current registers.
 950          */
 951         audit_syscall_exit(regs);
 952
 953         /*
 954          * Note that we haven't updated the ->syscall field for the
 955          * current thread. This isn't a problem because it will have
 956          * been set on syscall entry and there hasn't been an opportunity
 957          * for a PTRACE_SET_SYSCALL since then.
 958          */
 959         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 960                 trace_sys_exit(regs, regs_return_value(regs));
 961
 962         if (test_thread_flag(TIF_SYSCALL_TRACE))
 963                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
 964 }