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                 if (count < PTRACE_HBP_ADDR_SZ)
 555                         return -EINVAL;
 556                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
 557                                          offset, offset + PTRACE_HBP_ADDR_SZ);
 558                 if (ret)
 559                         return ret;
 560                 ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
 561                 if (ret)
 562                         return ret;
 563                 offset += PTRACE_HBP_ADDR_SZ;
 564
 565                 if (!count)
 566                         break;
 567                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
 568                                          offset, offset + PTRACE_HBP_CTRL_SZ);
 569                 if (ret)
 570                         return ret;
 571                 ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
 572                 if (ret)
 573                         return ret;
 574                 offset += PTRACE_HBP_CTRL_SZ;
 575
 576                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 577                                                 offset,
 578                                                 offset + PTRACE_HBP_PAD_SZ);
 579                 if (ret)
 580                         return ret;
 581                 offset += PTRACE_HBP_PAD_SZ;
 582                 idx++;
 583         }
 584
 585         return 0;
 586 }
 587 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
 588
 589 static int gpr_get(struct task_struct *target,
 590                    const struct user_regset *regset,
 591                    unsigned int pos, unsigned int count,
 592                    void *kbuf, void __user *ubuf)
 593 {
 594         struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
 595         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 596 }
 597
 598 static int gpr_set(struct task_struct *target, const struct user_regset *regset,
 599                    unsigned int pos, unsigned int count,
 600                    const void *kbuf, const void __user *ubuf)
 601 {
 602         int ret;
 603         struct user_pt_regs newregs = task_pt_regs(target)->user_regs;
 604
 605         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
 606         if (ret)
 607                 return ret;
 608
 609         if (!valid_user_regs(&newregs, target))
 610                 return -EINVAL;
 611
 612         task_pt_regs(target)->user_regs = newregs;
 613         return 0;
 614 }
 615
 616 /*
 617  * TODO: update fp accessors for lazy context switching (sync/flush hwstate)
 618  */
 619 static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 620                    unsigned int pos, unsigned int count,
 621                    void *kbuf, void __user *ubuf)
 622 {
 623         struct user_fpsimd_state *uregs;
 624         uregs = &target->thread.fpsimd_state.user_fpsimd;
 625         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 626 }
 627
 628 static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 629                    unsigned int pos, unsigned int count,
 630                    const void *kbuf, const void __user *ubuf)
 631 {
 632         int ret;
 633         struct user_fpsimd_state newstate =
 634                 target->thread.fpsimd_state.user_fpsimd;
 635
 636         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 637         if (ret)
 638                 return ret;
 639
 640         target->thread.fpsimd_state.user_fpsimd = newstate;
 641         fpsimd_flush_task_state(target);
 642         return ret;
 643 }
 644
 645 static int tls_get(struct task_struct *target, const struct user_regset *regset,
 646                    unsigned int pos, unsigned int count,
 647                    void *kbuf, void __user *ubuf)
 648 {
 649         unsigned long *tls = &target->thread.tp_value;
 650         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, tls, 0, -1);
 651 }
 652
 653 static int tls_set(struct task_struct *target, const struct user_regset *regset,
 654                    unsigned int pos, unsigned int count,
 655                    const void *kbuf, const void __user *ubuf)
 656 {
 657         int ret;
 658         unsigned long tls = target->thread.tp_value;
 659
 660         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 661         if (ret)
 662                 return ret;
 663
 664         target->thread.tp_value = tls;
 665         return ret;
 666 }
 667
 668 static int system_call_get(struct task_struct *target,
 669                            const struct user_regset *regset,
 670                            unsigned int pos, unsigned int count,
 671                            void *kbuf, void __user *ubuf)
 672 {
 673         int syscallno = task_pt_regs(target)->syscallno;
 674
 675         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 676                                    &syscallno, 0, -1);
 677 }
 678
 679 static int system_call_set(struct task_struct *target,
 680                            const struct user_regset *regset,
 681                            unsigned int pos, unsigned int count,
 682                            const void *kbuf, const void __user *ubuf)
 683 {
 684         int syscallno = task_pt_regs(target)->syscallno;
 685         int ret;
 686
 687         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
 688         if (ret)
 689                 return ret;
 690
 691         task_pt_regs(target)->syscallno = syscallno;
 692         return ret;
 693 }
 694
 695 enum aarch64_regset {
 696         REGSET_GPR,
 697         REGSET_FPR,
 698         REGSET_TLS,
 699 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 700         REGSET_HW_BREAK,
 701         REGSET_HW_WATCH,
 702 #endif
 703         REGSET_SYSTEM_CALL,
 704 };
 705
 706 static const struct user_regset aarch64_regsets[] = {
 707         [REGSET_GPR] = {
 708                 .core_note_type = NT_PRSTATUS,
 709                 .n = sizeof(struct user_pt_regs) / sizeof(u64),
 710                 .size = sizeof(u64),
 711                 .align = sizeof(u64),
 712                 .get = gpr_get,
 713                 .set = gpr_set
 714         },
 715         [REGSET_FPR] = {
 716                 .core_note_type = NT_PRFPREG,
 717                 .n = sizeof(struct user_fpsimd_state) / sizeof(u32),
 718                 /*
 719                  * We pretend we have 32-bit registers because the fpsr and
 720                  * fpcr are 32-bits wide.
 721                  */
 722                 .size = sizeof(u32),
 723                 .align = sizeof(u32),
 724                 .get = fpr_get,
 725                 .set = fpr_set
 726         },
 727         [REGSET_TLS] = {
 728                 .core_note_type = NT_ARM_TLS,
 729                 .n = 1,
 730                 .size = sizeof(void *),
 731                 .align = sizeof(void *),
 732                 .get = tls_get,
 733                 .set = tls_set,
 734         },
 735 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 736         [REGSET_HW_BREAK] = {
 737                 .core_note_type = NT_ARM_HW_BREAK,
 738                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 739                 .size = sizeof(u32),
 740                 .align = sizeof(u32),
 741                 .get = hw_break_get,
 742                 .set = hw_break_set,
 743         },
 744         [REGSET_HW_WATCH] = {
 745                 .core_note_type = NT_ARM_HW_WATCH,
 746                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 747                 .size = sizeof(u32),
 748                 .align = sizeof(u32),
 749                 .get = hw_break_get,
 750                 .set = hw_break_set,
 751         },
 752 #endif
 753         [REGSET_SYSTEM_CALL] = {
 754                 .core_note_type = NT_ARM_SYSTEM_CALL,
 755                 .n = 1,
 756                 .size = sizeof(int),
 757                 .align = sizeof(int),
 758                 .get = system_call_get,
 759                 .set = system_call_set,
 760         },
 761 };
 762
 763 static const struct user_regset_view user_aarch64_view = {
 764         .name = "aarch64", .e_machine = EM_AARCH64,
 765         .regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
 766 };
 767
 768 #ifdef CONFIG_COMPAT
 769 #include <linux/compat.h>
 770
 771 enum compat_regset {
 772         REGSET_COMPAT_GPR,
 773         REGSET_COMPAT_VFP,
 774 };
 775
 776 static int compat_gpr_get(struct task_struct *target,
 777                           const struct user_regset *regset,
 778                           unsigned int pos, unsigned int count,
 779                           void *kbuf, void __user *ubuf)
 780 {
 781         int ret = 0;
 782         unsigned int i, start, num_regs;
 783
 784         /* Calculate the number of AArch32 registers contained in count */
 785         num_regs = count / regset->size;
 786
 787         /* Convert pos into an register number */
 788         start = pos / regset->size;
 789
 790         if (start + num_regs > regset->n)
 791                 return -EIO;
 792
 793         for (i = 0; i < num_regs; ++i) {
 794                 unsigned int idx = start + i;
 795                 compat_ulong_t reg;
 796
 797                 switch (idx) {
 798                 case 15:
 799                         reg = task_pt_regs(target)->pc;
 800                         break;
 801                 case 16:
 802                         reg = task_pt_regs(target)->pstate;
 803                         break;
 804                 case 17:
 805                         reg = task_pt_regs(target)->orig_x0;
 806                         break;
 807                 default:
 808                         reg = task_pt_regs(target)->regs[idx];
 809                 }
 810
 811                 if (kbuf) {
 812                         memcpy(kbuf, &reg, sizeof(reg));
 813                         kbuf += sizeof(reg);
 814                 } else {
 815                         ret = copy_to_user(ubuf, &reg, sizeof(reg));
 816                         if (ret) {
 817                                 ret = -EFAULT;
 818                                 break;
 819                         }
 820
 821                         ubuf += sizeof(reg);
 822                 }
 823         }
 824
 825         return ret;
 826 }
 827
 828 static int compat_gpr_set(struct task_struct *target,
 829                           const struct user_regset *regset,
 830                           unsigned int pos, unsigned int count,
 831                           const void *kbuf, const void __user *ubuf)
 832 {
 833         struct pt_regs newregs;
 834         int ret = 0;
 835         unsigned int i, start, num_regs;
 836
 837         /* Calculate the number of AArch32 registers contained in count */
 838         num_regs = count / regset->size;
 839
 840         /* Convert pos into an register number */
 841         start = pos / regset->size;
 842
 843         if (start + num_regs > regset->n)
 844                 return -EIO;
 845
 846         newregs = *task_pt_regs(target);
 847
 848         for (i = 0; i < num_regs; ++i) {
 849                 unsigned int idx = start + i;
 850                 compat_ulong_t reg;
 851
 852                 if (kbuf) {
 853                         memcpy(&reg, kbuf, sizeof(reg));
 854                         kbuf += sizeof(reg);
 855                 } else {
 856                         ret = copy_from_user(&reg, ubuf, sizeof(reg));
 857                         if (ret) {
 858                                 ret = -EFAULT;
 859                                 break;
 860                         }
 861
 862                         ubuf += sizeof(reg);
 863                 }
 864
 865                 switch (idx) {
 866                 case 15:
 867                         newregs.pc = reg;
 868                         break;
 869                 case 16:
 870                         newregs.pstate = reg;
 871                         break;
 872                 case 17:
 873                         newregs.orig_x0 = reg;
 874                         break;
 875                 default:
 876                         newregs.regs[idx] = reg;
 877                 }
 878
 879         }
 880
 881         if (valid_user_regs(&newregs.user_regs, target))
 882                 *task_pt_regs(target) = newregs;
 883         else
 884                 ret = -EINVAL;
 885
 886         return ret;
 887 }
 888
 889 static int compat_vfp_get(struct task_struct *target,
 890                           const struct user_regset *regset,
 891                           unsigned int pos, unsigned int count,
 892                           void *kbuf, void __user *ubuf)
 893 {
 894         struct user_fpsimd_state *uregs;
 895         compat_ulong_t fpscr;
 896         int ret;
 897
 898         uregs = &target->thread.fpsimd_state.user_fpsimd;
 899
 900         /*
 901          * The VFP registers are packed into the fpsimd_state, so they all sit
 902          * nicely together for us. We just need to create the fpscr separately.
 903          */
 904         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0,
 905                                   VFP_STATE_SIZE - sizeof(compat_ulong_t));
 906
 907         if (count && !ret) {
 908                 fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
 909                         (uregs->fpcr & VFP_FPSCR_CTRL_MASK);
 910                 ret = put_user(fpscr, (compat_ulong_t *)ubuf);
 911         }
 912
 913         return ret;
 914 }
 915
 916 static int compat_vfp_set(struct task_struct *target,
 917                           const struct user_regset *regset,
 918                           unsigned int pos, unsigned int count,
 919                           const void *kbuf, const void __user *ubuf)
 920 {
 921         struct user_fpsimd_state *uregs;
 922         compat_ulong_t fpscr;
 923         int ret;
 924
 925         if (pos + count > VFP_STATE_SIZE)
 926                 return -EIO;
 927
 928         uregs = &target->thread.fpsimd_state.user_fpsimd;
 929
 930         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
 931                                  VFP_STATE_SIZE - sizeof(compat_ulong_t));
 932
 933         if (count && !ret) {
 934                 ret = get_user(fpscr, (compat_ulong_t *)ubuf);
 935                 uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
 936                 uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 937         }
 938
 939         fpsimd_flush_task_state(target);
 940         return ret;
 941 }
 942
 943 static int compat_tls_get(struct task_struct *target,
 944                           const struct user_regset *regset, unsigned int pos,
 945                           unsigned int count, void *kbuf, void __user *ubuf)
 946 {
 947         compat_ulong_t tls = (compat_ulong_t)target->thread.tp_value;
 948         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 949 }
 950
 951 static int compat_tls_set(struct task_struct *target,
 952                           const struct user_regset *regset, unsigned int pos,
 953                           unsigned int count, const void *kbuf,
 954                           const void __user *ubuf)
 955 {
 956         int ret;
 957         compat_ulong_t tls = target->thread.tp_value;
 958
 959         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 960         if (ret)
 961                 return ret;
 962
 963         target->thread.tp_value = tls;
 964         return ret;
 965 }
 966
 967 static const struct user_regset aarch32_regsets[] = {
 968         [REGSET_COMPAT_GPR] = {
 969                 .core_note_type = NT_PRSTATUS,
 970                 .n = COMPAT_ELF_NGREG,
 971                 .size = sizeof(compat_elf_greg_t),
 972                 .align = sizeof(compat_elf_greg_t),
 973                 .get = compat_gpr_get,
 974                 .set = compat_gpr_set
 975         },
 976         [REGSET_COMPAT_VFP] = {
 977                 .core_note_type = NT_ARM_VFP,
 978                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 979                 .size = sizeof(compat_ulong_t),
 980                 .align = sizeof(compat_ulong_t),
 981                 .get = compat_vfp_get,
 982                 .set = compat_vfp_set
 983         },
 984 };
 985
 986 static const struct user_regset_view user_aarch32_view = {
 987         .name = "aarch32", .e_machine = EM_ARM,
 988         .regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
 989 };
 990
 991 static const struct user_regset aarch32_ptrace_regsets[] = {
 992         [REGSET_GPR] = {
 993                 .core_note_type = NT_PRSTATUS,
 994                 .n = COMPAT_ELF_NGREG,
 995                 .size = sizeof(compat_elf_greg_t),
 996                 .align = sizeof(compat_elf_greg_t),
 997                 .get = compat_gpr_get,
 998                 .set = compat_gpr_set
 999         },
1000         [REGSET_FPR] = {
1001                 .core_note_type = NT_ARM_VFP,
1002                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
1003                 .size = sizeof(compat_ulong_t),
1004                 .align = sizeof(compat_ulong_t),
1005                 .get = compat_vfp_get,
1006                 .set = compat_vfp_set
1007         },
1008         [REGSET_TLS] = {
1009                 .core_note_type = NT_ARM_TLS,
1010                 .n = 1,
1011                 .size = sizeof(compat_ulong_t),
1012                 .align = sizeof(compat_ulong_t),
1013                 .get = compat_tls_get,
1014                 .set = compat_tls_set,
1015         },
1016 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1017         [REGSET_HW_BREAK] = {
1018                 .core_note_type = NT_ARM_HW_BREAK,
1019                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
1020                 .size = sizeof(u32),
1021                 .align = sizeof(u32),
1022                 .get = hw_break_get,
1023                 .set = hw_break_set,
1024         },
1025         [REGSET_HW_WATCH] = {
1026                 .core_note_type = NT_ARM_HW_WATCH,
1027                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
1028                 .size = sizeof(u32),
1029                 .align = sizeof(u32),
1030                 .get = hw_break_get,
1031                 .set = hw_break_set,
1032         },
1033 #endif
1034         [REGSET_SYSTEM_CALL] = {
1035                 .core_note_type = NT_ARM_SYSTEM_CALL,
1036                 .n = 1,
1037                 .size = sizeof(int),
1038                 .align = sizeof(int),
1039                 .get = system_call_get,
1040                 .set = system_call_set,
1041         },
1042 };
1043
1044 static const struct user_regset_view user_aarch32_ptrace_view = {
1045         .name = "aarch32", .e_machine = EM_ARM,
1046         .regsets = aarch32_ptrace_regsets, .n = ARRAY_SIZE(aarch32_ptrace_regsets)
1047 };
1048
1049 static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
1050                                    compat_ulong_t __user *ret)
1051 {
1052         compat_ulong_t tmp;
1053
1054         if (off & 3)
1055                 return -EIO;
1056
1057         if (off == COMPAT_PT_TEXT_ADDR)
1058                 tmp = tsk->mm->start_code;
1059         else if (off == COMPAT_PT_DATA_ADDR)
1060                 tmp = tsk->mm->start_data;
1061         else if (off == COMPAT_PT_TEXT_END_ADDR)
1062                 tmp = tsk->mm->end_code;
1063         else if (off < sizeof(compat_elf_gregset_t))
1064                 return copy_regset_to_user(tsk, &user_aarch32_view,
1065                                            REGSET_COMPAT_GPR, off,
1066                                            sizeof(compat_ulong_t), ret);
1067         else if (off >= COMPAT_USER_SZ)
1068                 return -EIO;
1069         else
1070                 tmp = 0;
1071
1072         return put_user(tmp, ret);
1073 }
1074
1075 static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
1076                                     compat_ulong_t val)
1077 {
1078         int ret;
1079         mm_segment_t old_fs = get_fs();
1080
1081         if (off & 3 || off >= COMPAT_USER_SZ)
1082                 return -EIO;
1083
1084         if (off >= sizeof(compat_elf_gregset_t))
1085                 return 0;
1086
1087         set_fs(KERNEL_DS);
1088         ret = copy_regset_from_user(tsk, &user_aarch32_view,
1089                                     REGSET_COMPAT_GPR, off,
1090                                     sizeof(compat_ulong_t),
1091                                     &val);
1092         set_fs(old_fs);
1093
1094         return ret;
1095 }
1096
1097 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1098
1099 /*
1100  * Convert a virtual register number into an index for a thread_info
1101  * breakpoint array. Breakpoints are identified using positive numbers
1102  * whilst watchpoints are negative. The registers are laid out as pairs
1103  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
1104  * Register 0 is reserved for describing resource information.
1105  */
1106 static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
1107 {
1108         return (abs(num) - 1) >> 1;
1109 }
1110
1111 static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
1112 {
1113         u8 num_brps, num_wrps, debug_arch, wp_len;
1114         u32 reg = 0;
1115
1116         num_brps        = hw_breakpoint_slots(TYPE_INST);
1117         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
1118
1119         debug_arch      = debug_monitors_arch();
1120         wp_len          = 8;
1121         reg             |= debug_arch;
1122         reg             <<= 8;
1123         reg             |= wp_len;
1124         reg             <<= 8;
1125         reg             |= num_wrps;
1126         reg             <<= 8;
1127         reg             |= num_brps;
1128
1129         *kdata = reg;
1130         return 0;
1131 }
1132
1133 static int compat_ptrace_hbp_get(unsigned int note_type,
1134                                  struct task_struct *tsk,
1135                                  compat_long_t num,
1136                                  u32 *kdata)
1137 {
1138         u64 addr = 0;
1139         u32 ctrl = 0;
1140
1141         int err, idx = compat_ptrace_hbp_num_to_idx(num);;
1142
1143         if (num & 1) {
1144                 err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
1145                 *kdata = (u32)addr;
1146         } else {
1147                 err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
1148                 *kdata = ctrl;
1149         }
1150
1151         return err;
1152 }
1153
1154 static int compat_ptrace_hbp_set(unsigned int note_type,
1155                                  struct task_struct *tsk,
1156                                  compat_long_t num,
1157                                  u32 *kdata)
1158 {
1159         u64 addr;
1160         u32 ctrl;
1161
1162         int err, idx = compat_ptrace_hbp_num_to_idx(num);
1163
1164         if (num & 1) {
1165                 addr = *kdata;
1166                 err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
1167         } else {
1168                 ctrl = *kdata;
1169                 err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
1170         }
1171
1172         return err;
1173 }
1174
1175 static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
1176                                     compat_ulong_t __user *data)
1177 {
1178         int ret;
1179         u32 kdata;
1180         mm_segment_t old_fs = get_fs();
1181
1182         set_fs(KERNEL_DS);
1183         /* Watchpoint */
1184         if (num < 0) {
1185                 ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
1186         /* Resource info */
1187         } else if (num == 0) {
1188                 ret = compat_ptrace_hbp_get_resource_info(&kdata);
1189         /* Breakpoint */
1190         } else {
1191                 ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
1192         }
1193         set_fs(old_fs);
1194
1195         if (!ret)
1196                 ret = put_user(kdata, data);
1197
1198         return ret;
1199 }
1200
1201 static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
1202                                     compat_ulong_t __user *data)
1203 {
1204         int ret;
1205         u32 kdata = 0;
1206         mm_segment_t old_fs = get_fs();
1207
1208         if (num == 0)
1209                 return 0;
1210
1211         ret = get_user(kdata, data);
1212         if (ret)
1213                 return ret;
1214
1215         set_fs(KERNEL_DS);
1216         if (num < 0)
1217                 ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
1218         else
1219                 ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
1220         set_fs(old_fs);
1221
1222         return ret;
1223 }
1224 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
1225
1226 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1227                         compat_ulong_t caddr, compat_ulong_t cdata)
1228 {
1229         unsigned long addr = caddr;
1230         unsigned long data = cdata;
1231         void __user *datap = compat_ptr(data);
1232         int ret;
1233
1234         switch (request) {
1235                 case PTRACE_PEEKUSR:
1236                         ret = compat_ptrace_read_user(child, addr, datap);
1237                         break;
1238
1239                 case PTRACE_POKEUSR:
1240                         ret = compat_ptrace_write_user(child, addr, data);
1241                         break;
1242
1243                 case COMPAT_PTRACE_GETREGS:
1244                         ret = copy_regset_to_user(child,
1245                                                   &user_aarch32_view,
1246                                                   REGSET_COMPAT_GPR,
1247                                                   0, sizeof(compat_elf_gregset_t),
1248                                                   datap);
1249                         break;
1250
1251                 case COMPAT_PTRACE_SETREGS:
1252                         ret = copy_regset_from_user(child,
1253                                                     &user_aarch32_view,
1254                                                     REGSET_COMPAT_GPR,
1255                                                     0, sizeof(compat_elf_gregset_t),
1256                                                     datap);
1257                         break;
1258
1259                 case COMPAT_PTRACE_GET_THREAD_AREA:
1260                         ret = put_user((compat_ulong_t)child->thread.tp_value,
1261                                        (compat_ulong_t __user *)datap);
1262                         break;
1263
1264                 case COMPAT_PTRACE_SET_SYSCALL:
1265                         task_pt_regs(child)->syscallno = data;
1266                         ret = 0;
1267                         break;
1268
1269                 case COMPAT_PTRACE_GETVFPREGS:
1270                         ret = copy_regset_to_user(child,
1271                                                   &user_aarch32_view,
1272                                                   REGSET_COMPAT_VFP,
1273                                                   0, VFP_STATE_SIZE,
1274                                                   datap);
1275                         break;
1276
1277                 case COMPAT_PTRACE_SETVFPREGS:
1278                         ret = copy_regset_from_user(child,
1279                                                     &user_aarch32_view,
1280                                                     REGSET_COMPAT_VFP,
1281                                                     0, VFP_STATE_SIZE,
1282                                                     datap);
1283                         break;
1284
1285 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1286                 case COMPAT_PTRACE_GETHBPREGS:
1287                         ret = compat_ptrace_gethbpregs(child, addr, datap);
1288                         break;
1289
1290                 case COMPAT_PTRACE_SETHBPREGS:
1291                         ret = compat_ptrace_sethbpregs(child, addr, datap);
1292                         break;
1293 #endif
1294
1295                 default:
1296                         ret = compat_ptrace_request(child, request, addr,
1297                                                     data);
1298                         break;
1299         }
1300
1301         return ret;
1302 }
1303 #endif /* CONFIG_COMPAT */
1304
1305 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1306 {
1307 #ifdef CONFIG_COMPAT
1308         /*
1309          * Core dumping of 32-bit tasks or compat ptrace requests must use the
1310          * user_aarch32_view compatible with arm32. Native ptrace requests on
1311          * 32-bit children use an extended user_aarch32_ptrace_view to allow
1312          * access to the TLS register.
1313          */
1314         if (is_compat_task())
1315                 return &user_aarch32_view;
1316         else if (is_compat_thread(task_thread_info(task)))
1317                 return &user_aarch32_ptrace_view;
1318 #endif
1319         return &user_aarch64_view;
1320 }
1321
1322 long arch_ptrace(struct task_struct *child, long request,
1323                  unsigned long addr, unsigned long data)
1324 {
1325         return ptrace_request(child, request, addr, data);
1326 }
1327
1328 enum ptrace_syscall_dir {
1329         PTRACE_SYSCALL_ENTER = 0,
1330         PTRACE_SYSCALL_EXIT,
1331 };
1332
1333 static void tracehook_report_syscall(struct pt_regs *regs,
1334                                      enum ptrace_syscall_dir dir)
1335 {
1336         int regno;
1337         unsigned long saved_reg;
1338
1339         /*
1340          * A scratch register (ip(r12) on AArch32, x7 on AArch64) is
1341          * used to denote syscall entry/exit:
1342          */
1343         regno = (is_compat_task() ? 12 : 7);
1344         saved_reg = regs->regs[regno];
1345         regs->regs[regno] = dir;
1346
1347         if (dir == PTRACE_SYSCALL_EXIT)
1348                 tracehook_report_syscall_exit(regs, 0);
1349         else if (tracehook_report_syscall_entry(regs))
1350                 regs->syscallno = ~0UL;
1351
1352         regs->regs[regno] = saved_reg;
1353 }
1354
1355 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
1356 {
1357         if (test_thread_flag(TIF_SYSCALL_TRACE))
1358                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
1359
1360         /* Do the secure computing after ptrace; failures should be fast. */
1361         if (secure_computing(NULL) == -1)
1362                 return -1;
1363
1364         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1365                 trace_sys_enter(regs, regs->syscallno);
1366
1367         audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
1368                             regs->regs[2], regs->regs[3]);
1369
1370         return regs->syscallno;
1371 }
1372
1373 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
1374 {
1375         audit_syscall_exit(regs);
1376
1377         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1378                 trace_sys_exit(regs, regs_return_value(regs));
1379
1380         if (test_thread_flag(TIF_SYSCALL_TRACE))
1381                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
1382 }
1383
1384 /*
1385  * Bits which are always architecturally RES0 per ARM DDI 0487A.h
1386  * Userspace cannot use these until they have an architectural meaning.
1387  * We also reserve IL for the kernel; SS is handled dynamically.
1388  */
1389 #define SPSR_EL1_AARCH64_RES0_BITS \
1390         (GENMASK_ULL(63,32) | GENMASK_ULL(27, 22) | GENMASK_ULL(20, 10) | \
1391          GENMASK_ULL(5, 5))
1392 #define SPSR_EL1_AARCH32_RES0_BITS \
1393         (GENMASK_ULL(63,32) | GENMASK_ULL(24, 22) | GENMASK_ULL(20,20))
1394
1395 static int valid_compat_regs(struct user_pt_regs *regs)
1396 {
1397         regs->pstate &= ~SPSR_EL1_AARCH32_RES0_BITS;
1398
1399         if (!system_supports_mixed_endian_el0()) {
1400                 if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
1401                         regs->pstate |= COMPAT_PSR_E_BIT;
1402                 else
1403                         regs->pstate &= ~COMPAT_PSR_E_BIT;
1404         }
1405
1406         if (user_mode(regs) && (regs->pstate & PSR_MODE32_BIT) &&
1407             (regs->pstate & COMPAT_PSR_A_BIT) == 0 &&
1408             (regs->pstate & COMPAT_PSR_I_BIT) == 0 &&
1409             (regs->pstate & COMPAT_PSR_F_BIT) == 0) {
1410                 return 1;
1411         }
1412
1413         /*
1414          * Force PSR to a valid 32-bit EL0t, preserving the same bits as
1415          * arch/arm.
1416          */
1417         regs->pstate &= COMPAT_PSR_N_BIT | COMPAT_PSR_Z_BIT |
1418                         COMPAT_PSR_C_BIT | COMPAT_PSR_V_BIT |
1419                         COMPAT_PSR_Q_BIT | COMPAT_PSR_IT_MASK |
1420                         COMPAT_PSR_GE_MASK | COMPAT_PSR_E_BIT |
1421                         COMPAT_PSR_T_BIT;
1422         regs->pstate |= PSR_MODE32_BIT;
1423
1424         return 0;
1425 }
1426
1427 static int valid_native_regs(struct user_pt_regs *regs)
1428 {
1429         regs->pstate &= ~SPSR_EL1_AARCH64_RES0_BITS;
1430
1431         if (user_mode(regs) && !(regs->pstate & PSR_MODE32_BIT) &&
1432             (regs->pstate & PSR_D_BIT) == 0 &&
1433             (regs->pstate & PSR_A_BIT) == 0 &&
1434             (regs->pstate & PSR_I_BIT) == 0 &&
1435             (regs->pstate & PSR_F_BIT) == 0) {
1436                 return 1;
1437         }
1438
1439         /* Force PSR to a valid 64-bit EL0t */
1440         regs->pstate &= PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT;
1441
1442         return 0;
1443 }
1444
1445 /*
1446  * Are the current registers suitable for user mode? (used to maintain
1447  * security in signal handlers)
1448  */
1449 int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task)
1450 {
1451         if (!test_tsk_thread_flag(task, TIF_SINGLESTEP))
1452                 regs->pstate &= ~DBG_SPSR_SS;
1453
1454         if (is_compat_thread(task_thread_info(task)))
1455                 return valid_compat_regs(regs);
1456         else
1457                 return valid_native_regs(regs);
1458 }