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