arch/arm64/kernel/ptrace.c

   1 /*
   2  * Based on 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  * Copyright (C) 2012 ARM Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <linux/audit.h>
  23 #include <linux/compat.h>
  24 #include <linux/kernel.h>
  25 #include <linux/sched.h>
  26 #include <linux/mm.h>
  27 #include <linux/smp.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/user.h>
  30 #include <linux/seccomp.h>
  31 #include <linux/security.h>
  32 #include <linux/init.h>
  33 #include <linux/signal.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/perf_event.h>
  36 #include <linux/hw_breakpoint.h>
  37 #include <linux/regset.h>
  38 #include <linux/tracehook.h>
  39 #include <linux/elf.h>
  40
  41 #include <asm/compat.h>
  42 #include <asm/debug-monitors.h>
  43 #include <asm/pgtable.h>
  44 #include <asm/syscall.h>
  45 #include <asm/traps.h>
  46 #include <asm/system_misc.h>
  47
  48 #define CREATE_TRACE_POINTS
  49 #include <trace/events/syscalls.h>
  50
  51 struct pt_regs_offset {
  52         const char *name;
  53         int offset;
  54 };
  55
  56 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
  57 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  58 #define GPR_OFFSET_NAME(r) \
  59         {.name = "x" #r, .offset = offsetof(struct pt_regs, regs[r])}
  60
  61 static const struct pt_regs_offset regoffset_table[] = {
  62         GPR_OFFSET_NAME(0),
  63         GPR_OFFSET_NAME(1),
  64         GPR_OFFSET_NAME(2),
  65         GPR_OFFSET_NAME(3),
  66         GPR_OFFSET_NAME(4),
  67         GPR_OFFSET_NAME(5),
  68         GPR_OFFSET_NAME(6),
  69         GPR_OFFSET_NAME(7),
  70         GPR_OFFSET_NAME(8),
  71         GPR_OFFSET_NAME(9),
  72         GPR_OFFSET_NAME(10),
  73         GPR_OFFSET_NAME(11),
  74         GPR_OFFSET_NAME(12),
  75         GPR_OFFSET_NAME(13),
  76         GPR_OFFSET_NAME(14),
  77         GPR_OFFSET_NAME(15),
  78         GPR_OFFSET_NAME(16),
  79         GPR_OFFSET_NAME(17),
  80         GPR_OFFSET_NAME(18),
  81         GPR_OFFSET_NAME(19),
  82         GPR_OFFSET_NAME(20),
  83         GPR_OFFSET_NAME(21),
  84         GPR_OFFSET_NAME(22),
  85         GPR_OFFSET_NAME(23),
  86         GPR_OFFSET_NAME(24),
  87         GPR_OFFSET_NAME(25),
  88         GPR_OFFSET_NAME(26),
  89         GPR_OFFSET_NAME(27),
  90         GPR_OFFSET_NAME(28),
  91         GPR_OFFSET_NAME(29),
  92         GPR_OFFSET_NAME(30),
  93         {.name = "lr", .offset = offsetof(struct pt_regs, regs[30])},
  94         REG_OFFSET_NAME(sp),
  95         REG_OFFSET_NAME(pc),
  96         REG_OFFSET_NAME(pstate),
  97         REG_OFFSET_END,
  98 };
  99
 100 /**
 101  * regs_query_register_offset() - query register offset from its name
 102  * @name:       the name of a register
 103  *
 104  * regs_query_register_offset() returns the offset of a register in struct
 105  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 106  */
 107 int regs_query_register_offset(const char *name)
 108 {
 109         const struct pt_regs_offset *roff;
 110
 111         for (roff = regoffset_table; roff->name != NULL; roff++)
 112                 if (!strcmp(roff->name, name))
 113                         return roff->offset;
 114         return -EINVAL;
 115 }
 116
 117 /**
 118  * regs_within_kernel_stack() - check the address in the stack
 119  * @regs:      pt_regs which contains kernel stack pointer.
 120  * @addr:      address which is checked.
 121  *
 122  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 123  * If @addr is within the kernel stack, it returns true. If not, returns false.
 124  */
 125 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 126 {
 127         return ((addr & ~(THREAD_SIZE - 1))  ==
 128                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
 129                 on_irq_stack(addr, raw_smp_processor_id());
 130 }
 131
 132 /**
 133  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 134  * @regs:       pt_regs which contains kernel stack pointer.
 135  * @n:          stack entry number.
 136  *
 137  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 138  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 139  * this returns 0.
 140  */
 141 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 142 {
 143         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 144
 145         addr += n;
 146         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 147                 return *addr;
 148         else
 149                 return 0;
 150 }
 151
 152 /*
 153  * TODO: does not yet catch signals sent when the child dies.
 154  * in exit.c or in signal.c.
 155  */
 156
 157 /*
 158  * Called by kernel/ptrace.c when detaching..
 159  */
 160 void ptrace_disable(struct task_struct *child)
 161 {
 162         /*
 163          * This would be better off in core code, but PTRACE_DETACH has
 164          * grown its fair share of arch-specific worts and changing it
 165          * is likely to cause regressions on obscure architectures.
 166          */
 167         user_disable_single_step(child);
 168 }
 169
 170 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 171 /*
 172  * Handle hitting a HW-breakpoint.
 173  */
 174 static void ptrace_hbptriggered(struct perf_event *bp,
 175                                 struct perf_sample_data *data,
 176                                 struct pt_regs *regs)
 177 {
 178         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 179         siginfo_t info = {
 180                 .si_signo       = SIGTRAP,
 181                 .si_errno       = 0,
 182                 .si_code        = TRAP_HWBKPT,
 183                 .si_addr        = (void __user *)(bkpt->trigger),
 184         };
 185
 186 #ifdef CONFIG_COMPAT
 187         int i;
 188
 189         if (!is_compat_task())
 190                 goto send_sig;
 191
 192         for (i = 0; i < ARM_MAX_BRP; ++i) {
 193                 if (current->thread.debug.hbp_break[i] == bp) {
 194                         info.si_errno = (i << 1) + 1;
 195                         break;
 196                 }
 197         }
 198
 199         for (i = 0; i < ARM_MAX_WRP; ++i) {
 200                 if (current->thread.debug.hbp_watch[i] == bp) {
 201                         info.si_errno = -((i << 1) + 1);
 202                         break;
 203                 }
 204         }
 205
 206 send_sig:
 207 #endif
 208         force_sig_info(SIGTRAP, &info, current);
 209 }
 210
 211 /*
 212  * Unregister breakpoints from this task and reset the pointers in
 213  * the thread_struct.
 214  */
 215 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 216 {
 217         int i;
 218         struct thread_struct *t = &tsk->thread;
 219
 220         for (i = 0; i < ARM_MAX_BRP; i++) {
 221                 if (t->debug.hbp_break[i]) {
 222                         unregister_hw_breakpoint(t->debug.hbp_break[i]);
 223                         t->debug.hbp_break[i] = NULL;
 224                 }
 225         }
 226
 227         for (i = 0; i < ARM_MAX_WRP; i++) {
 228                 if (t->debug.hbp_watch[i]) {
 229                         unregister_hw_breakpoint(t->debug.hbp_watch[i]);
 230                         t->debug.hbp_watch[i] = NULL;
 231                 }
 232         }
 233 }
 234
 235 void ptrace_hw_copy_thread(struct task_struct *tsk)
 236 {
 237         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 238 }
 239
 240 static struct perf_event *ptrace_hbp_get_event(unsigned int note_type,
 241                                                struct task_struct *tsk,
 242                                                unsigned long idx)
 243 {
 244         struct perf_event *bp = ERR_PTR(-EINVAL);
 245
 246         switch (note_type) {
 247         case NT_ARM_HW_BREAK:
 248                 if (idx < ARM_MAX_BRP)
 249                         bp = tsk->thread.debug.hbp_break[idx];
 250                 break;
 251         case NT_ARM_HW_WATCH:
 252                 if (idx < ARM_MAX_WRP)
 253                         bp = tsk->thread.debug.hbp_watch[idx];
 254                 break;
 255         }
 256
 257         return bp;
 258 }
 259
 260 static int ptrace_hbp_set_event(unsigned int note_type,
 261                                 struct task_struct *tsk,
 262                                 unsigned long idx,
 263                                 struct perf_event *bp)
 264 {
 265         int err = -EINVAL;
 266
 267         switch (note_type) {
 268         case NT_ARM_HW_BREAK:
 269                 if (idx < ARM_MAX_BRP) {
 270                         tsk->thread.debug.hbp_break[idx] = bp;
 271                         err = 0;
 272                 }
 273                 break;
 274         case NT_ARM_HW_WATCH:
 275                 if (idx < ARM_MAX_WRP) {
 276                         tsk->thread.debug.hbp_watch[idx] = bp;
 277                         err = 0;
 278                 }
 279                 break;
 280         }
 281
 282         return err;
 283 }
 284
 285 static struct perf_event *ptrace_hbp_create(unsigned int note_type,
 286                                             struct task_struct *tsk,
 287                                             unsigned long idx)
 288 {
 289         struct perf_event *bp;
 290         struct perf_event_attr attr;
 291         int err, type;
 292
 293         switch (note_type) {
 294         case NT_ARM_HW_BREAK:
 295                 type = HW_BREAKPOINT_X;
 296                 break;
 297         case NT_ARM_HW_WATCH:
 298                 type = HW_BREAKPOINT_RW;
 299                 break;
 300         default:
 301                 return ERR_PTR(-EINVAL);
 302         }
 303
 304         ptrace_breakpoint_init(&attr);
 305
 306         /*
 307          * Initialise fields to sane defaults
 308          * (i.e. values that will pass validation).
 309          */
 310         attr.bp_addr    = 0;
 311         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 312         attr.bp_type    = type;
 313         attr.disabled   = 1;
 314
 315         bp = register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, tsk);
 316         if (IS_ERR(bp))
 317                 return bp;
 318
 319         err = ptrace_hbp_set_event(note_type, tsk, idx, bp);
 320         if (err)
 321                 return ERR_PTR(err);
 322
 323         return bp;
 324 }
 325
 326 static int ptrace_hbp_fill_attr_ctrl(unsigned int note_type,
 327                                      struct arch_hw_breakpoint_ctrl ctrl,
 328                                      struct perf_event_attr *attr)
 329 {
 330         int err, len, type, offset, disabled = !ctrl.enabled;
 331
 332         attr->disabled = disabled;
 333         if (disabled)
 334                 return 0;
 335
 336         err = arch_bp_generic_fields(ctrl, &len, &type, &offset);
 337         if (err)
 338                 return err;
 339
 340         switch (note_type) {
 341         case NT_ARM_HW_BREAK:
 342                 if ((type & HW_BREAKPOINT_X) != type)
 343                         return -EINVAL;
 344                 break;
 345         case NT_ARM_HW_WATCH:
 346                 if ((type & HW_BREAKPOINT_RW) != type)
 347                         return -EINVAL;
 348                 break;
 349         default:
 350                 return -EINVAL;
 351         }
 352
 353         attr->bp_len    = len;
 354         attr->bp_type   = type;
 355         attr->bp_addr   += offset;
 356
 357         return 0;
 358 }
 359
 360 static int ptrace_hbp_get_resource_info(unsigned int note_type, u32 *info)
 361 {
 362         u8 num;
 363         u32 reg = 0;
 364
 365         switch (note_type) {
 366         case NT_ARM_HW_BREAK:
 367                 num = hw_breakpoint_slots(TYPE_INST);
 368                 break;
 369         case NT_ARM_HW_WATCH:
 370                 num = hw_breakpoint_slots(TYPE_DATA);
 371                 break;
 372         default:
 373                 return -EINVAL;
 374         }
 375
 376         reg |= debug_monitors_arch();
 377         reg <<= 8;
 378         reg |= num;
 379
 380         *info = reg;
 381         return 0;
 382 }
 383
 384 static int ptrace_hbp_get_ctrl(unsigned int note_type,
 385                                struct task_struct *tsk,
 386                                unsigned long idx,
 387                                u32 *ctrl)
 388 {
 389         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 390
 391         if (IS_ERR(bp))
 392                 return PTR_ERR(bp);
 393
 394         *ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
 395         return 0;
 396 }
 397
 398 static int ptrace_hbp_get_addr(unsigned int note_type,
 399                                struct task_struct *tsk,
 400                                unsigned long idx,
 401                                u64 *addr)
 402 {
 403         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 404
 405         if (IS_ERR(bp))
 406                 return PTR_ERR(bp);
 407
 408         *addr = bp ? counter_arch_bp(bp)->address : 0;
 409         return 0;
 410 }
 411
 412 static struct perf_event *ptrace_hbp_get_initialised_bp(unsigned int note_type,
 413                                                         struct task_struct *tsk,
 414                                                         unsigned long idx)
 415 {
 416         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 417
 418         if (!bp)
 419                 bp = ptrace_hbp_create(note_type, tsk, idx);
 420
 421         return bp;
 422 }
 423
 424 static int ptrace_hbp_set_ctrl(unsigned int note_type,
 425                                struct task_struct *tsk,
 426                                unsigned long idx,
 427                                u32 uctrl)
 428 {
 429         int err;
 430         struct perf_event *bp;
 431         struct perf_event_attr attr;
 432         struct arch_hw_breakpoint_ctrl ctrl;
 433
 434         bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
 435         if (IS_ERR(bp)) {
 436                 err = PTR_ERR(bp);
 437                 return err;
 438         }
 439
 440         attr = bp->attr;
 441         decode_ctrl_reg(uctrl, &ctrl);
 442         err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr);
 443         if (err)
 444                 return err;
 445
 446         return modify_user_hw_breakpoint(bp, &attr);
 447 }
 448
 449 static int ptrace_hbp_set_addr(unsigned int note_type,
 450                                struct task_struct *tsk,
 451                                unsigned long idx,
 452                                u64 addr)
 453 {
 454         int err;
 455         struct perf_event *bp;
 456         struct perf_event_attr attr;
 457
 458         bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
 459         if (IS_ERR(bp)) {
 460                 err = PTR_ERR(bp);
 461                 return err;
 462         }
 463
 464         attr = bp->attr;
 465         attr.bp_addr = addr;
 466         err = modify_user_hw_breakpoint(bp, &attr);
 467         return err;
 468 }
 469
 470 #define PTRACE_HBP_ADDR_SZ      sizeof(u64)
 471 #define PTRACE_HBP_CTRL_SZ      sizeof(u32)
 472 #define PTRACE_HBP_PAD_SZ       sizeof(u32)
 473
 474 static int hw_break_get(struct task_struct *target,
 475                         const struct user_regset *regset,
 476                         unsigned int pos, unsigned int count,
 477                         void *kbuf, void __user *ubuf)
 478 {
 479         unsigned int note_type = regset->core_note_type;
 480         int ret, idx = 0, offset, limit;
 481         u32 info, ctrl;
 482         u64 addr;
 483
 484         /* Resource info */
 485         ret = ptrace_hbp_get_resource_info(note_type, &info);
 486         if (ret)
 487                 return ret;
 488
 489         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &info, 0,
 490                                   sizeof(info));
 491         if (ret)
 492                 return ret;
 493
 494         /* Pad */
 495         offset = offsetof(struct user_hwdebug_state, pad);
 496         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, offset,
 497                                        offset + PTRACE_HBP_PAD_SZ);
 498         if (ret)
 499                 return ret;
 500
 501         /* (address, ctrl) registers */
 502         offset = offsetof(struct user_hwdebug_state, dbg_regs);
 503         limit = regset->n * regset->size;
 504         while (count && offset < limit) {
 505                 ret = ptrace_hbp_get_addr(note_type, target, idx, &addr);
 506                 if (ret)
 507                         return ret;
 508                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &addr,
 509                                           offset, offset + PTRACE_HBP_ADDR_SZ);
 510                 if (ret)
 511                         return ret;
 512                 offset += PTRACE_HBP_ADDR_SZ;
 513
 514                 ret = ptrace_hbp_get_ctrl(note_type, target, idx, &ctrl);
 515                 if (ret)
 516                         return ret;
 517                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &ctrl,
 518                                           offset, offset + PTRACE_HBP_CTRL_SZ);
 519                 if (ret)
 520                         return ret;
 521                 offset += PTRACE_HBP_CTRL_SZ;
 522
 523                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 524                                                offset,
 525                                                offset + PTRACE_HBP_PAD_SZ);
 526                 if (ret)
 527                         return ret;
 528                 offset += PTRACE_HBP_PAD_SZ;
 529                 idx++;
 530         }
 531
 532         return 0;
 533 }
 534
 535 static int hw_break_set(struct task_struct *target,
 536                         const struct user_regset *regset,
 537                         unsigned int pos, unsigned int count,
 538                         const void *kbuf, const void __user *ubuf)
 539 {
 540         unsigned int note_type = regset->core_note_type;
 541         int ret, idx = 0, offset, limit;
 542         u32 ctrl;
 543         u64 addr;
 544
 545         /* Resource info and pad */
 546         offset = offsetof(struct user_hwdebug_state, dbg_regs);
 547         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, offset);
 548         if (ret)
 549                 return ret;
 550
 551         /* (address, ctrl) registers */
 552         limit = regset->n * regset->size;
 553         while (count && offset < limit) {
 554                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
 555                                          offset, offset + PTRACE_HBP_ADDR_SZ);
 556                 if (ret)
 557                         return ret;
 558                 ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
 559                 if (ret)
 560                         return ret;
 561                 offset += PTRACE_HBP_ADDR_SZ;
 562
 563                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
 564                                          offset, offset + PTRACE_HBP_CTRL_SZ);
 565                 if (ret)
 566                         return ret;
 567                 ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
 568                 if (ret)
 569                         return ret;
 570                 offset += PTRACE_HBP_CTRL_SZ;
 571
 572                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 573                                                 offset,
 574                                                 offset + PTRACE_HBP_PAD_SZ);
 575                 if (ret)
 576                         return ret;
 577                 offset += PTRACE_HBP_PAD_SZ;
 578                 idx++;
 579         }
 580
 581         return 0;
 582 }
 583 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
 584
 585 static int gpr_get(struct task_struct *target,
 586                    const struct user_regset *regset,
 587                    unsigned int pos, unsigned int count,
 588                    void *kbuf, void __user *ubuf)
 589 {
 590         struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
 591         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 592 }
 593
 594 static int gpr_set(struct task_struct *target, const struct user_regset *regset,
 595                    unsigned int pos, unsigned int count,
 596                    const void *kbuf, const void __user *ubuf)
 597 {
 598         int ret;
 599         struct user_pt_regs newregs;
 600
 601         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
 602         if (ret)
 603                 return ret;
 604
 605         if (!valid_user_regs(&newregs, target))
 606                 return -EINVAL;
 607
 608         task_pt_regs(target)->user_regs = newregs;
 609         return 0;
 610 }
 611
 612 /*
 613  * TODO: update fp accessors for lazy context switching (sync/flush hwstate)
 614  */
 615 static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 616                    unsigned int pos, unsigned int count,
 617                    void *kbuf, void __user *ubuf)
 618 {
 619         struct user_fpsimd_state *uregs;
 620         uregs = &target->thread.fpsimd_state.user_fpsimd;
 621         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 622 }
 623
 624 static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 625                    unsigned int pos, unsigned int count,
 626                    const void *kbuf, const void __user *ubuf)
 627 {
 628         int ret;
 629         struct user_fpsimd_state newstate;
 630
 631         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 632         if (ret)
 633                 return ret;
 634
 635         target->thread.fpsimd_state.user_fpsimd = newstate;
 636         fpsimd_flush_task_state(target);
 637         return ret;
 638 }
 639
 640 static int tls_get(struct task_struct *target, const struct user_regset *regset,
 641                    unsigned int pos, unsigned int count,
 642                    void *kbuf, void __user *ubuf)
 643 {
 644         unsigned long *tls = &target->thread.tp_value;
 645         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, tls, 0, -1);
 646 }
 647
 648 static int tls_set(struct task_struct *target, const struct user_regset *regset,
 649                    unsigned int pos, unsigned int count,
 650                    const void *kbuf, const void __user *ubuf)
 651 {
 652         int ret;
 653         unsigned long tls;
 654
 655         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 656         if (ret)
 657                 return ret;
 658
 659         target->thread.tp_value = tls;
 660         return ret;
 661 }
 662
 663 static int system_call_get(struct task_struct *target,
 664                            const struct user_regset *regset,
 665                            unsigned int pos, unsigned int count,
 666                            void *kbuf, void __user *ubuf)
 667 {
 668         int syscallno = task_pt_regs(target)->syscallno;
 669
 670         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 671                                    &syscallno, 0, -1);
 672 }
 673
 674 static int system_call_set(struct task_struct *target,
 675                            const struct user_regset *regset,
 676                            unsigned int pos, unsigned int count,
 677                            const void *kbuf, const void __user *ubuf)
 678 {
 679         int syscallno, ret;
 680
 681         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
 682         if (ret)
 683                 return ret;
 684
 685         task_pt_regs(target)->syscallno = syscallno;
 686         return ret;
 687 }
 688
 689 enum aarch64_regset {
 690         REGSET_GPR,
 691         REGSET_FPR,
 692         REGSET_TLS,
 693 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 694         REGSET_HW_BREAK,
 695         REGSET_HW_WATCH,
 696 #endif
 697         REGSET_SYSTEM_CALL,
 698 };
 699
 700 static const struct user_regset aarch64_regsets[] = {
 701         [REGSET_GPR] = {
 702                 .core_note_type = NT_PRSTATUS,
 703                 .n = sizeof(struct user_pt_regs) / sizeof(u64),
 704                 .size = sizeof(u64),
 705                 .align = sizeof(u64),
 706                 .get = gpr_get,
 707                 .set = gpr_set
 708         },
 709         [REGSET_FPR] = {
 710                 .core_note_type = NT_PRFPREG,
 711                 .n = sizeof(struct user_fpsimd_state) / sizeof(u32),
 712                 /*
 713                  * We pretend we have 32-bit registers because the fpsr and
 714                  * fpcr are 32-bits wide.
 715                  */
 716                 .size = sizeof(u32),
 717                 .align = sizeof(u32),
 718                 .get = fpr_get,
 719                 .set = fpr_set
 720         },
 721         [REGSET_TLS] = {
 722                 .core_note_type = NT_ARM_TLS,
 723                 .n = 1,
 724                 .size = sizeof(void *),
 725                 .align = sizeof(void *),
 726                 .get = tls_get,
 727                 .set = tls_set,
 728         },
 729 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 730         [REGSET_HW_BREAK] = {
 731                 .core_note_type = NT_ARM_HW_BREAK,
 732                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 733                 .size = sizeof(u32),
 734                 .align = sizeof(u32),
 735                 .get = hw_break_get,
 736                 .set = hw_break_set,
 737         },
 738         [REGSET_HW_WATCH] = {
 739                 .core_note_type = NT_ARM_HW_WATCH,
 740                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 741                 .size = sizeof(u32),
 742                 .align = sizeof(u32),
 743                 .get = hw_break_get,
 744                 .set = hw_break_set,
 745         },
 746 #endif
 747         [REGSET_SYSTEM_CALL] = {
 748                 .core_note_type = NT_ARM_SYSTEM_CALL,
 749                 .n = 1,
 750                 .size = sizeof(int),
 751                 .align = sizeof(int),
 752                 .get = system_call_get,
 753                 .set = system_call_set,
 754         },
 755 };
 756
 757 static const struct user_regset_view user_aarch64_view = {
 758         .name = "aarch64", .e_machine = EM_AARCH64,
 759         .regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
 760 };
 761
 762 #ifdef CONFIG_COMPAT
 763 #include <linux/compat.h>
 764
 765 enum compat_regset {
 766         REGSET_COMPAT_GPR,
 767         REGSET_COMPAT_VFP,
 768 };
 769
 770 static int compat_gpr_get(struct task_struct *target,
 771                           const struct user_regset *regset,
 772                           unsigned int pos, unsigned int count,
 773                           void *kbuf, void __user *ubuf)
 774 {
 775         int ret = 0;
 776         unsigned int i, start, num_regs;
 777
 778         /* Calculate the number of AArch32 registers contained in count */
 779         num_regs = count / regset->size;
 780
 781         /* Convert pos into an register number */
 782         start = pos / regset->size;
 783
 784         if (start + num_regs > regset->n)
 785                 return -EIO;
 786
 787         for (i = 0; i < num_regs; ++i) {
 788                 unsigned int idx = start + i;
 789                 compat_ulong_t reg;
 790
 791                 switch (idx) {
 792                 case 15:
 793                         reg = task_pt_regs(target)->pc;
 794                         break;
 795                 case 16:
 796                         reg = task_pt_regs(target)->pstate;
 797                         break;
 798                 case 17:
 799                         reg = task_pt_regs(target)->orig_x0;
 800                         break;
 801                 default:
 802                         reg = task_pt_regs(target)->regs[idx];
 803                 }
 804
 805                 if (kbuf) {
 806                         memcpy(kbuf, &reg, sizeof(reg));
 807                         kbuf += sizeof(reg);
 808                 } else {
 809                         ret = copy_to_user(ubuf, &reg, sizeof(reg));
 810                         if (ret) {
 811                                 ret = -EFAULT;
 812                                 break;
 813                         }
 814
 815                         ubuf += sizeof(reg);
 816                 }
 817         }
 818
 819         return ret;
 820 }
 821
 822 static int compat_gpr_set(struct task_struct *target,
 823                           const struct user_regset *regset,
 824                           unsigned int pos, unsigned int count,
 825                           const void *kbuf, const void __user *ubuf)
 826 {
 827         struct pt_regs newregs;
 828         int ret = 0;
 829         unsigned int i, start, num_regs;
 830
 831         /* Calculate the number of AArch32 registers contained in count */
 832         num_regs = count / regset->size;
 833
 834         /* Convert pos into an register number */
 835         start = pos / regset->size;
 836
 837         if (start + num_regs > regset->n)
 838                 return -EIO;
 839
 840         newregs = *task_pt_regs(target);
 841
 842         for (i = 0; i < num_regs; ++i) {
 843                 unsigned int idx = start + i;
 844                 compat_ulong_t reg;
 845
 846                 if (kbuf) {
 847                         memcpy(&reg, kbuf, sizeof(reg));
 848                         kbuf += sizeof(reg);
 849                 } else {
 850                         ret = copy_from_user(&reg, ubuf, sizeof(reg));
 851                         if (ret) {
 852                                 ret = -EFAULT;
 853                                 break;
 854                         }
 855
 856                         ubuf += sizeof(reg);
 857                 }
 858
 859                 switch (idx) {
 860                 case 15:
 861                         newregs.pc = reg;
 862                         break;
 863                 case 16:
 864                         newregs.pstate = reg;
 865                         break;
 866                 case 17:
 867                         newregs.orig_x0 = reg;
 868                         break;
 869                 default:
 870                         newregs.regs[idx] = reg;
 871                 }
 872
 873         }
 874
 875         if (valid_user_regs(&newregs.user_regs, target))
 876                 *task_pt_regs(target) = newregs;
 877         else
 878                 ret = -EINVAL;
 879
 880         return ret;
 881 }
 882
 883 static int compat_vfp_get(struct task_struct *target,
 884                           const struct user_regset *regset,
 885                           unsigned int pos, unsigned int count,
 886                           void *kbuf, void __user *ubuf)
 887 {
 888         struct user_fpsimd_state *uregs;
 889         compat_ulong_t fpscr;
 890         int ret;
 891
 892         uregs = &target->thread.fpsimd_state.user_fpsimd;
 893
 894         /*
 895          * The VFP registers are packed into the fpsimd_state, so they all sit
 896          * nicely together for us. We just need to create the fpscr separately.
 897          */
 898         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0,
 899                                   VFP_STATE_SIZE - sizeof(compat_ulong_t));
 900
 901         if (count && !ret) {
 902                 fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
 903                         (uregs->fpcr & VFP_FPSCR_CTRL_MASK);
 904                 ret = put_user(fpscr, (compat_ulong_t *)ubuf);
 905         }
 906
 907         return ret;
 908 }
 909
 910 static int compat_vfp_set(struct task_struct *target,
 911                           const struct user_regset *regset,
 912                           unsigned int pos, unsigned int count,
 913                           const void *kbuf, const void __user *ubuf)
 914 {
 915         struct user_fpsimd_state *uregs;
 916         compat_ulong_t fpscr;
 917         int ret;
 918
 919         if (pos + count > VFP_STATE_SIZE)
 920                 return -EIO;
 921
 922         uregs = &target->thread.fpsimd_state.user_fpsimd;
 923
 924         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
 925                                  VFP_STATE_SIZE - sizeof(compat_ulong_t));
 926
 927         if (count && !ret) {
 928                 ret = get_user(fpscr, (compat_ulong_t *)ubuf);
 929                 uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
 930                 uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 931         }
 932
 933         fpsimd_flush_task_state(target);
 934         return ret;
 935 }
 936
 937 static int compat_tls_get(struct task_struct *target,
 938                           const struct user_regset *regset, unsigned int pos,
 939                           unsigned int count, void *kbuf, void __user *ubuf)
 940 {
 941         compat_ulong_t tls = (compat_ulong_t)target->thread.tp_value;
 942         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 943 }
 944
 945 static int compat_tls_set(struct task_struct *target,
 946                           const struct user_regset *regset, unsigned int pos,
 947                           unsigned int count, const void *kbuf,
 948                           const void __user *ubuf)
 949 {
 950         int ret;
 951         compat_ulong_t tls;
 952
 953         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 954         if (ret)
 955                 return ret;
 956
 957         target->thread.tp_value = tls;
 958         return ret;
 959 }
 960
 961 static const struct user_regset aarch32_regsets[] = {
 962         [REGSET_COMPAT_GPR] = {
 963                 .core_note_type = NT_PRSTATUS,
 964                 .n = COMPAT_ELF_NGREG,
 965                 .size = sizeof(compat_elf_greg_t),
 966                 .align = sizeof(compat_elf_greg_t),
 967                 .get = compat_gpr_get,
 968                 .set = compat_gpr_set
 969         },
 970         [REGSET_COMPAT_VFP] = {
 971                 .core_note_type = NT_ARM_VFP,
 972                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 973                 .size = sizeof(compat_ulong_t),
 974                 .align = sizeof(compat_ulong_t),
 975                 .get = compat_vfp_get,
 976                 .set = compat_vfp_set
 977         },
 978 };
 979
 980 static const struct user_regset_view user_aarch32_view = {
 981         .name = "aarch32", .e_machine = EM_ARM,
 982         .regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
 983 };
 984
 985 static const struct user_regset aarch32_ptrace_regsets[] = {
 986         [REGSET_GPR] = {
 987                 .core_note_type = NT_PRSTATUS,
 988                 .n = COMPAT_ELF_NGREG,
 989                 .size = sizeof(compat_elf_greg_t),
 990                 .align = sizeof(compat_elf_greg_t),
 991                 .get = compat_gpr_get,
 992                 .set = compat_gpr_set
 993         },
 994         [REGSET_FPR] = {
 995                 .core_note_type = NT_ARM_VFP,
 996                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 997                 .size = sizeof(compat_ulong_t),
 998                 .align = sizeof(compat_ulong_t),
 999                 .get = compat_vfp_get,
1000                 .set = compat_vfp_set
1001         },
1002         [REGSET_TLS] = {
1003                 .core_note_type = NT_ARM_TLS,
1004                 .n = 1,
1005                 .size = sizeof(compat_ulong_t),
1006                 .align = sizeof(compat_ulong_t),
1007                 .get = compat_tls_get,
1008                 .set = compat_tls_set,
1009         },
1010 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1011         [REGSET_HW_BREAK] = {
1012                 .core_note_type = NT_ARM_HW_BREAK,
1013                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
1014                 .size = sizeof(u32),
1015                 .align = sizeof(u32),
1016                 .get = hw_break_get,
1017                 .set = hw_break_set,
1018         },
1019         [REGSET_HW_WATCH] = {
1020                 .core_note_type = NT_ARM_HW_WATCH,
1021                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
1022                 .size = sizeof(u32),
1023                 .align = sizeof(u32),
1024                 .get = hw_break_get,
1025                 .set = hw_break_set,
1026         },
1027 #endif
1028         [REGSET_SYSTEM_CALL] = {
1029                 .core_note_type = NT_ARM_SYSTEM_CALL,
1030                 .n = 1,
1031                 .size = sizeof(int),
1032                 .align = sizeof(int),
1033                 .get = system_call_get,
1034                 .set = system_call_set,
1035         },
1036 };
1037
1038 static const struct user_regset_view user_aarch32_ptrace_view = {
1039         .name = "aarch32", .e_machine = EM_ARM,
1040         .regsets = aarch32_ptrace_regsets, .n = ARRAY_SIZE(aarch32_ptrace_regsets)
1041 };
1042
1043 static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
1044                                    compat_ulong_t __user *ret)
1045 {
1046         compat_ulong_t tmp;
1047
1048         if (off & 3)
1049                 return -EIO;
1050
1051         if (off == COMPAT_PT_TEXT_ADDR)
1052                 tmp = tsk->mm->start_code;
1053         else if (off == COMPAT_PT_DATA_ADDR)
1054                 tmp = tsk->mm->start_data;
1055         else if (off == COMPAT_PT_TEXT_END_ADDR)
1056                 tmp = tsk->mm->end_code;
1057         else if (off < sizeof(compat_elf_gregset_t))
1058                 return copy_regset_to_user(tsk, &user_aarch32_view,
1059                                            REGSET_COMPAT_GPR, off,
1060                                            sizeof(compat_ulong_t), ret);
1061         else if (off >= COMPAT_USER_SZ)
1062                 return -EIO;
1063         else
1064                 tmp = 0;
1065
1066         return put_user(tmp, ret);
1067 }
1068
1069 static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
1070                                     compat_ulong_t val)
1071 {
1072         int ret;
1073         mm_segment_t old_fs = get_fs();
1074
1075         if (off & 3 || off >= COMPAT_USER_SZ)
1076                 return -EIO;
1077
1078         if (off >= sizeof(compat_elf_gregset_t))
1079                 return 0;
1080
1081         set_fs(KERNEL_DS);
1082         ret = copy_regset_from_user(tsk, &user_aarch32_view,
1083                                     REGSET_COMPAT_GPR, off,
1084                                     sizeof(compat_ulong_t),
1085                                     &val);
1086         set_fs(old_fs);
1087
1088         return ret;
1089 }
1090
1091 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1092
1093 /*
1094  * Convert a virtual register number into an index for a thread_info
1095  * breakpoint array. Breakpoints are identified using positive numbers
1096  * whilst watchpoints are negative. The registers are laid out as pairs
1097  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
1098  * Register 0 is reserved for describing resource information.
1099  */
1100 static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
1101 {
1102         return (abs(num) - 1) >> 1;
1103 }
1104
1105 static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
1106 {
1107         u8 num_brps, num_wrps, debug_arch, wp_len;
1108         u32 reg = 0;
1109
1110         num_brps        = hw_breakpoint_slots(TYPE_INST);
1111         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
1112
1113         debug_arch      = debug_monitors_arch();
1114         wp_len          = 8;
1115         reg             |= debug_arch;
1116         reg             <<= 8;
1117         reg             |= wp_len;
1118         reg             <<= 8;
1119         reg             |= num_wrps;
1120         reg             <<= 8;
1121         reg             |= num_brps;
1122
1123         *kdata = reg;
1124         return 0;
1125 }
1126
1127 static int compat_ptrace_hbp_get(unsigned int note_type,
1128                                  struct task_struct *tsk,
1129                                  compat_long_t num,
1130                                  u32 *kdata)
1131 {
1132         u64 addr = 0;
1133         u32 ctrl = 0;
1134
1135         int err, idx = compat_ptrace_hbp_num_to_idx(num);;
1136
1137         if (num & 1) {
1138                 err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
1139                 *kdata = (u32)addr;
1140         } else {
1141                 err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
1142                 *kdata = ctrl;
1143         }
1144
1145         return err;
1146 }
1147
1148 static int compat_ptrace_hbp_set(unsigned int note_type,
1149                                  struct task_struct *tsk,
1150                                  compat_long_t num,
1151                                  u32 *kdata)
1152 {
1153         u64 addr;
1154         u32 ctrl;
1155
1156         int err, idx = compat_ptrace_hbp_num_to_idx(num);
1157
1158         if (num & 1) {
1159                 addr = *kdata;
1160                 err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
1161         } else {
1162                 ctrl = *kdata;
1163                 err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
1164         }
1165
1166         return err;
1167 }
1168
1169 static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
1170                                     compat_ulong_t __user *data)
1171 {
1172         int ret;
1173         u32 kdata;
1174         mm_segment_t old_fs = get_fs();
1175
1176         set_fs(KERNEL_DS);
1177         /* Watchpoint */
1178         if (num < 0) {
1179                 ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
1180         /* Resource info */
1181         } else if (num == 0) {
1182                 ret = compat_ptrace_hbp_get_resource_info(&kdata);
1183         /* Breakpoint */
1184         } else {
1185                 ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
1186         }
1187         set_fs(old_fs);
1188
1189         if (!ret)
1190                 ret = put_user(kdata, data);
1191
1192         return ret;
1193 }
1194
1195 static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
1196                                     compat_ulong_t __user *data)
1197 {
1198         int ret;
1199         u32 kdata = 0;
1200         mm_segment_t old_fs = get_fs();
1201
1202         if (num == 0)
1203                 return 0;
1204
1205         ret = get_user(kdata, data);
1206         if (ret)
1207                 return ret;
1208
1209         set_fs(KERNEL_DS);
1210         if (num < 0)
1211                 ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
1212         else
1213                 ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
1214         set_fs(old_fs);
1215
1216         return ret;
1217 }
1218 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
1219
1220 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1221                         compat_ulong_t caddr, compat_ulong_t cdata)
1222 {
1223         unsigned long addr = caddr;
1224         unsigned long data = cdata;
1225         void __user *datap = compat_ptr(data);
1226         int ret;
1227
1228         switch (request) {
1229                 case PTRACE_PEEKUSR:
1230                         ret = compat_ptrace_read_user(child, addr, datap);
1231                         break;
1232
1233                 case PTRACE_POKEUSR:
1234                         ret = compat_ptrace_write_user(child, addr, data);
1235                         break;
1236
1237                 case COMPAT_PTRACE_GETREGS:
1238                         ret = copy_regset_to_user(child,
1239                                                   &user_aarch32_view,
1240                                                   REGSET_COMPAT_GPR,
1241                                                   0, sizeof(compat_elf_gregset_t),
1242                                                   datap);
1243                         break;
1244
1245                 case COMPAT_PTRACE_SETREGS:
1246                         ret = copy_regset_from_user(child,
1247                                                     &user_aarch32_view,
1248                                                     REGSET_COMPAT_GPR,
1249                                                     0, sizeof(compat_elf_gregset_t),
1250                                                     datap);
1251                         break;
1252
1253                 case COMPAT_PTRACE_GET_THREAD_AREA:
1254                         ret = put_user((compat_ulong_t)child->thread.tp_value,
1255                                        (compat_ulong_t __user *)datap);
1256                         break;
1257
1258                 case COMPAT_PTRACE_SET_SYSCALL:
1259                         task_pt_regs(child)->syscallno = data;
1260                         ret = 0;
1261                         break;
1262
1263                 case COMPAT_PTRACE_GETVFPREGS:
1264                         ret = copy_regset_to_user(child,
1265                                                   &user_aarch32_view,
1266                                                   REGSET_COMPAT_VFP,
1267                                                   0, VFP_STATE_SIZE,
1268                                                   datap);
1269                         break;
1270
1271                 case COMPAT_PTRACE_SETVFPREGS:
1272                         ret = copy_regset_from_user(child,
1273                                                     &user_aarch32_view,
1274                                                     REGSET_COMPAT_VFP,
1275                                                     0, VFP_STATE_SIZE,
1276                                                     datap);
1277                         break;
1278
1279 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1280                 case COMPAT_PTRACE_GETHBPREGS:
1281                         ret = compat_ptrace_gethbpregs(child, addr, datap);
1282                         break;
1283
1284                 case COMPAT_PTRACE_SETHBPREGS:
1285                         ret = compat_ptrace_sethbpregs(child, addr, datap);
1286                         break;
1287 #endif
1288
1289                 default:
1290                         ret = compat_ptrace_request(child, request, addr,
1291                                                     data);
1292                         break;
1293         }
1294
1295         return ret;
1296 }
1297 #endif /* CONFIG_COMPAT */
1298
1299 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1300 {
1301 #ifdef CONFIG_COMPAT
1302         /*
1303          * Core dumping of 32-bit tasks or compat ptrace requests must use the
1304          * user_aarch32_view compatible with arm32. Native ptrace requests on
1305          * 32-bit children use an extended user_aarch32_ptrace_view to allow
1306          * access to the TLS register.
1307          */
1308         if (is_compat_task())
1309                 return &user_aarch32_view;
1310         else if (is_compat_thread(task_thread_info(task)))
1311                 return &user_aarch32_ptrace_view;
1312 #endif
1313         return &user_aarch64_view;
1314 }
1315
1316 long arch_ptrace(struct task_struct *child, long request,
1317                  unsigned long addr, unsigned long data)
1318 {
1319         return ptrace_request(child, request, addr, data);
1320 }
1321
1322 enum ptrace_syscall_dir {
1323         PTRACE_SYSCALL_ENTER = 0,
1324         PTRACE_SYSCALL_EXIT,
1325 };
1326
1327 static void tracehook_report_syscall(struct pt_regs *regs,
1328                                      enum ptrace_syscall_dir dir)
1329 {
1330         int regno;
1331         unsigned long saved_reg;
1332
1333         /*
1334          * A scratch register (ip(r12) on AArch32, x7 on AArch64) is
1335          * used to denote syscall entry/exit:
1336          */
1337         regno = (is_compat_task() ? 12 : 7);
1338         saved_reg = regs->regs[regno];
1339         regs->regs[regno] = dir;
1340
1341         if (dir == PTRACE_SYSCALL_EXIT)
1342                 tracehook_report_syscall_exit(regs, 0);
1343         else if (tracehook_report_syscall_entry(regs))
1344                 regs->syscallno = ~0UL;
1345
1346         regs->regs[regno] = saved_reg;
1347 }
1348
1349 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
1350 {
1351         if (test_thread_flag(TIF_SYSCALL_TRACE))
1352                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
1353
1354         /* Do the secure computing after ptrace; failures should be fast. */
1355         if (secure_computing(NULL) == -1)
1356                 return -1;
1357
1358         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1359                 trace_sys_enter(regs, regs->syscallno);
1360
1361         audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
1362                             regs->regs[2], regs->regs[3]);
1363
1364         return regs->syscallno;
1365 }
1366
1367 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
1368 {
1369         audit_syscall_exit(regs);
1370
1371         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1372                 trace_sys_exit(regs, regs_return_value(regs));
1373
1374         if (test_thread_flag(TIF_SYSCALL_TRACE))
1375                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
1376 }
1377
1378 /*
1379  * Bits which are always architecturally RES0 per ARM DDI 0487A.h
1380  * Userspace cannot use these until they have an architectural meaning.
1381  * We also reserve IL for the kernel; SS is handled dynamically.
1382  */
1383 #define SPSR_EL1_AARCH64_RES0_BITS \
1384         (GENMASK_ULL(63,32) | GENMASK_ULL(27, 22) | GENMASK_ULL(20, 10) | \
1385          GENMASK_ULL(5, 5))
1386 #define SPSR_EL1_AARCH32_RES0_BITS \
1387         (GENMASK_ULL(63,32) | GENMASK_ULL(24, 22) | GENMASK_ULL(20,20))
1388
1389 static int valid_compat_regs(struct user_pt_regs *regs)
1390 {
1391         regs->pstate &= ~SPSR_EL1_AARCH32_RES0_BITS;
1392
1393         if (!system_supports_mixed_endian_el0()) {
1394                 if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
1395                         regs->pstate |= COMPAT_PSR_E_BIT;
1396                 else
1397                         regs->pstate &= ~COMPAT_PSR_E_BIT;
1398         }
1399
1400         if (user_mode(regs) && (regs->pstate & PSR_MODE32_BIT) &&
1401             (regs->pstate & COMPAT_PSR_A_BIT) == 0 &&
1402             (regs->pstate & COMPAT_PSR_I_BIT) == 0 &&
1403             (regs->pstate & COMPAT_PSR_F_BIT) == 0) {
1404                 return 1;
1405         }
1406
1407         /*
1408          * Force PSR to a valid 32-bit EL0t, preserving the same bits as
1409          * arch/arm.
1410          */
1411         regs->pstate &= COMPAT_PSR_N_BIT | COMPAT_PSR_Z_BIT |
1412                         COMPAT_PSR_C_BIT | COMPAT_PSR_V_BIT |
1413                         COMPAT_PSR_Q_BIT | COMPAT_PSR_IT_MASK |
1414                         COMPAT_PSR_GE_MASK | COMPAT_PSR_E_BIT |
1415                         COMPAT_PSR_T_BIT;
1416         regs->pstate |= PSR_MODE32_BIT;
1417
1418         return 0;
1419 }
1420
1421 static int valid_native_regs(struct user_pt_regs *regs)
1422 {
1423         regs->pstate &= ~SPSR_EL1_AARCH64_RES0_BITS;
1424
1425         if (user_mode(regs) && !(regs->pstate & PSR_MODE32_BIT) &&
1426             (regs->pstate & PSR_D_BIT) == 0 &&
1427             (regs->pstate & PSR_A_BIT) == 0 &&
1428             (regs->pstate & PSR_I_BIT) == 0 &&
1429             (regs->pstate & PSR_F_BIT) == 0) {
1430                 return 1;
1431         }
1432
1433         /* Force PSR to a valid 64-bit EL0t */
1434         regs->pstate &= PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT;
1435
1436         return 0;
1437 }
1438
1439 /*
1440  * Are the current registers suitable for user mode? (used to maintain
1441  * security in signal handlers)
1442  */
1443 int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task)
1444 {
1445         if (!test_tsk_thread_flag(task, TIF_SINGLESTEP))
1446                 regs->pstate &= ~DBG_SPSR_SS;
1447
1448         if (is_compat_thread(task_thread_info(task)))
1449                 return valid_compat_regs(regs);
1450         else
1451                 return valid_native_regs(regs);
1452 }