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