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/signal.h>
  26 #include <linux/sched/task_stack.h>
  27 #include <linux/mm.h>
  28 #include <linux/smp.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/user.h>
  31 #include <linux/seccomp.h>
  32 #include <linux/security.h>
  33 #include <linux/init.h>
  34 #include <linux/signal.h>
  35 #include <linux/uaccess.h>
  36 #include <linux/perf_event.h>
  37 #include <linux/hw_breakpoint.h>
  38 #include <linux/regset.h>
  39 #include <linux/tracehook.h>
  40 #include <linux/elf.h>
  41
  42 #include <asm/compat.h>
  43 #include <asm/debug-monitors.h>
  44 #include <asm/pgtable.h>
  45 #include <asm/syscall.h>
  46 #include <asm/traps.h>
  47 #include <asm/system_misc.h>
  48
  49 #define CREATE_TRACE_POINTS
  50 #include <trace/events/syscalls.h>
  51
  52 struct pt_regs_offset {
  53         const char *name;
  54         int offset;
  55 };
  56
  57 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
  58 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  59 #define GPR_OFFSET_NAME(r) \
  60         {.name = "x" #r, .offset = offsetof(struct pt_regs, regs[r])}
  61
  62 static const struct pt_regs_offset regoffset_table[] = {
  63         GPR_OFFSET_NAME(0),
  64         GPR_OFFSET_NAME(1),
  65         GPR_OFFSET_NAME(2),
  66         GPR_OFFSET_NAME(3),
  67         GPR_OFFSET_NAME(4),
  68         GPR_OFFSET_NAME(5),
  69         GPR_OFFSET_NAME(6),
  70         GPR_OFFSET_NAME(7),
  71         GPR_OFFSET_NAME(8),
  72         GPR_OFFSET_NAME(9),
  73         GPR_OFFSET_NAME(10),
  74         GPR_OFFSET_NAME(11),
  75         GPR_OFFSET_NAME(12),
  76         GPR_OFFSET_NAME(13),
  77         GPR_OFFSET_NAME(14),
  78         GPR_OFFSET_NAME(15),
  79         GPR_OFFSET_NAME(16),
  80         GPR_OFFSET_NAME(17),
  81         GPR_OFFSET_NAME(18),
  82         GPR_OFFSET_NAME(19),
  83         GPR_OFFSET_NAME(20),
  84         GPR_OFFSET_NAME(21),
  85         GPR_OFFSET_NAME(22),
  86         GPR_OFFSET_NAME(23),
  87         GPR_OFFSET_NAME(24),
  88         GPR_OFFSET_NAME(25),
  89         GPR_OFFSET_NAME(26),
  90         GPR_OFFSET_NAME(27),
  91         GPR_OFFSET_NAME(28),
  92         GPR_OFFSET_NAME(29),
  93         GPR_OFFSET_NAME(30),
  94         {.name = "lr", .offset = offsetof(struct pt_regs, regs[30])},
  95         REG_OFFSET_NAME(sp),
  96         REG_OFFSET_NAME(pc),
  97         REG_OFFSET_NAME(pstate),
  98         REG_OFFSET_END,
  99 };
 100
 101 /**
 102  * regs_query_register_offset() - query register offset from its name
 103  * @name:       the name of a register
 104  *
 105  * regs_query_register_offset() returns the offset of a register in struct
 106  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 107  */
 108 int regs_query_register_offset(const char *name)
 109 {
 110         const struct pt_regs_offset *roff;
 111
 112         for (roff = regoffset_table; roff->name != NULL; roff++)
 113                 if (!strcmp(roff->name, name))
 114                         return roff->offset;
 115         return -EINVAL;
 116 }
 117
 118 /**
 119  * regs_within_kernel_stack() - check the address in the stack
 120  * @regs:      pt_regs which contains kernel stack pointer.
 121  * @addr:      address which is checked.
 122  *
 123  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 124  * If @addr is within the kernel stack, it returns true. If not, returns false.
 125  */
 126 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
 127 {
 128         return ((addr & ~(THREAD_SIZE - 1))  ==
 129                 (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
 130                 on_irq_stack(addr, raw_smp_processor_id());
 131 }
 132
 133 /**
 134  * regs_get_kernel_stack_nth() - get Nth entry of the stack
 135  * @regs:       pt_regs which contains kernel stack pointer.
 136  * @n:          stack entry number.
 137  *
 138  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 139  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 140  * this returns 0.
 141  */
 142 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
 143 {
 144         unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
 145
 146         addr += n;
 147         if (regs_within_kernel_stack(regs, (unsigned long)addr))
 148                 return *addr;
 149         else
 150                 return 0;
 151 }
 152
 153 /*
 154  * TODO: does not yet catch signals sent when the child dies.
 155  * in exit.c or in signal.c.
 156  */
 157
 158 /*
 159  * Called by kernel/ptrace.c when detaching..
 160  */
 161 void ptrace_disable(struct task_struct *child)
 162 {
 163         /*
 164          * This would be better off in core code, but PTRACE_DETACH has
 165          * grown its fair share of arch-specific worts and changing it
 166          * is likely to cause regressions on obscure architectures.
 167          */
 168         user_disable_single_step(child);
 169 }
 170
 171 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 172 /*
 173  * Handle hitting a HW-breakpoint.
 174  */
 175 static void ptrace_hbptriggered(struct perf_event *bp,
 176                                 struct perf_sample_data *data,
 177                                 struct pt_regs *regs)
 178 {
 179         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
 180         siginfo_t info = {
 181                 .si_signo       = SIGTRAP,
 182                 .si_errno       = 0,
 183                 .si_code        = TRAP_HWBKPT,
 184                 .si_addr        = (void __user *)(bkpt->trigger),
 185         };
 186
 187 #ifdef CONFIG_COMPAT
 188         int i;
 189
 190         if (!is_compat_task())
 191                 goto send_sig;
 192
 193         for (i = 0; i < ARM_MAX_BRP; ++i) {
 194                 if (current->thread.debug.hbp_break[i] == bp) {
 195                         info.si_errno = (i << 1) + 1;
 196                         break;
 197                 }
 198         }
 199
 200         for (i = 0; i < ARM_MAX_WRP; ++i) {
 201                 if (current->thread.debug.hbp_watch[i] == bp) {
 202                         info.si_errno = -((i << 1) + 1);
 203                         break;
 204                 }
 205         }
 206
 207 send_sig:
 208 #endif
 209         force_sig_info(SIGTRAP, &info, current);
 210 }
 211
 212 /*
 213  * Unregister breakpoints from this task and reset the pointers in
 214  * the thread_struct.
 215  */
 216 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 217 {
 218         int i;
 219         struct thread_struct *t = &tsk->thread;
 220
 221         for (i = 0; i < ARM_MAX_BRP; i++) {
 222                 if (t->debug.hbp_break[i]) {
 223                         unregister_hw_breakpoint(t->debug.hbp_break[i]);
 224                         t->debug.hbp_break[i] = NULL;
 225                 }
 226         }
 227
 228         for (i = 0; i < ARM_MAX_WRP; i++) {
 229                 if (t->debug.hbp_watch[i]) {
 230                         unregister_hw_breakpoint(t->debug.hbp_watch[i]);
 231                         t->debug.hbp_watch[i] = NULL;
 232                 }
 233         }
 234 }
 235
 236 void ptrace_hw_copy_thread(struct task_struct *tsk)
 237 {
 238         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 239 }
 240
 241 static struct perf_event *ptrace_hbp_get_event(unsigned int note_type,
 242                                                struct task_struct *tsk,
 243                                                unsigned long idx)
 244 {
 245         struct perf_event *bp = ERR_PTR(-EINVAL);
 246
 247         switch (note_type) {
 248         case NT_ARM_HW_BREAK:
 249                 if (idx < ARM_MAX_BRP)
 250                         bp = tsk->thread.debug.hbp_break[idx];
 251                 break;
 252         case NT_ARM_HW_WATCH:
 253                 if (idx < ARM_MAX_WRP)
 254                         bp = tsk->thread.debug.hbp_watch[idx];
 255                 break;
 256         }
 257
 258         return bp;
 259 }
 260
 261 static int ptrace_hbp_set_event(unsigned int note_type,
 262                                 struct task_struct *tsk,
 263                                 unsigned long idx,
 264                                 struct perf_event *bp)
 265 {
 266         int err = -EINVAL;
 267
 268         switch (note_type) {
 269         case NT_ARM_HW_BREAK:
 270                 if (idx < ARM_MAX_BRP) {
 271                         tsk->thread.debug.hbp_break[idx] = bp;
 272                         err = 0;
 273                 }
 274                 break;
 275         case NT_ARM_HW_WATCH:
 276                 if (idx < ARM_MAX_WRP) {
 277                         tsk->thread.debug.hbp_watch[idx] = bp;
 278                         err = 0;
 279                 }
 280                 break;
 281         }
 282
 283         return err;
 284 }
 285
 286 static struct perf_event *ptrace_hbp_create(unsigned int note_type,
 287                                             struct task_struct *tsk,
 288                                             unsigned long idx)
 289 {
 290         struct perf_event *bp;
 291         struct perf_event_attr attr;
 292         int err, type;
 293
 294         switch (note_type) {
 295         case NT_ARM_HW_BREAK:
 296                 type = HW_BREAKPOINT_X;
 297                 break;
 298         case NT_ARM_HW_WATCH:
 299                 type = HW_BREAKPOINT_RW;
 300                 break;
 301         default:
 302                 return ERR_PTR(-EINVAL);
 303         }
 304
 305         ptrace_breakpoint_init(&attr);
 306
 307         /*
 308          * Initialise fields to sane defaults
 309          * (i.e. values that will pass validation).
 310          */
 311         attr.bp_addr    = 0;
 312         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 313         attr.bp_type    = type;
 314         attr.disabled   = 1;
 315
 316         bp = register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, tsk);
 317         if (IS_ERR(bp))
 318                 return bp;
 319
 320         err = ptrace_hbp_set_event(note_type, tsk, idx, bp);
 321         if (err)
 322                 return ERR_PTR(err);
 323
 324         return bp;
 325 }
 326
 327 static int ptrace_hbp_fill_attr_ctrl(unsigned int note_type,
 328                                      struct arch_hw_breakpoint_ctrl ctrl,
 329                                      struct perf_event_attr *attr)
 330 {
 331         int err, len, type, offset, disabled = !ctrl.enabled;
 332
 333         attr->disabled = disabled;
 334         if (disabled)
 335                 return 0;
 336
 337         err = arch_bp_generic_fields(ctrl, &len, &type, &offset);
 338         if (err)
 339                 return err;
 340
 341         switch (note_type) {
 342         case NT_ARM_HW_BREAK:
 343                 if ((type & HW_BREAKPOINT_X) != type)
 344                         return -EINVAL;
 345                 break;
 346         case NT_ARM_HW_WATCH:
 347                 if ((type & HW_BREAKPOINT_RW) != type)
 348                         return -EINVAL;
 349                 break;
 350         default:
 351                 return -EINVAL;
 352         }
 353
 354         attr->bp_len    = len;
 355         attr->bp_type   = type;
 356         attr->bp_addr   += offset;
 357
 358         return 0;
 359 }
 360
 361 static int ptrace_hbp_get_resource_info(unsigned int note_type, u32 *info)
 362 {
 363         u8 num;
 364         u32 reg = 0;
 365
 366         switch (note_type) {
 367         case NT_ARM_HW_BREAK:
 368                 num = hw_breakpoint_slots(TYPE_INST);
 369                 break;
 370         case NT_ARM_HW_WATCH:
 371                 num = hw_breakpoint_slots(TYPE_DATA);
 372                 break;
 373         default:
 374                 return -EINVAL;
 375         }
 376
 377         reg |= debug_monitors_arch();
 378         reg <<= 8;
 379         reg |= num;
 380
 381         *info = reg;
 382         return 0;
 383 }
 384
 385 static int ptrace_hbp_get_ctrl(unsigned int note_type,
 386                                struct task_struct *tsk,
 387                                unsigned long idx,
 388                                u32 *ctrl)
 389 {
 390         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 391
 392         if (IS_ERR(bp))
 393                 return PTR_ERR(bp);
 394
 395         *ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
 396         return 0;
 397 }
 398
 399 static int ptrace_hbp_get_addr(unsigned int note_type,
 400                                struct task_struct *tsk,
 401                                unsigned long idx,
 402                                u64 *addr)
 403 {
 404         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 405
 406         if (IS_ERR(bp))
 407                 return PTR_ERR(bp);
 408
 409         *addr = bp ? counter_arch_bp(bp)->address : 0;
 410         return 0;
 411 }
 412
 413 static struct perf_event *ptrace_hbp_get_initialised_bp(unsigned int note_type,
 414                                                         struct task_struct *tsk,
 415                                                         unsigned long idx)
 416 {
 417         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 418
 419         if (!bp)
 420                 bp = ptrace_hbp_create(note_type, tsk, idx);
 421
 422         return bp;
 423 }
 424
 425 static int ptrace_hbp_set_ctrl(unsigned int note_type,
 426                                struct task_struct *tsk,
 427                                unsigned long idx,
 428                                u32 uctrl)
 429 {
 430         int err;
 431         struct perf_event *bp;
 432         struct perf_event_attr attr;
 433         struct arch_hw_breakpoint_ctrl ctrl;
 434
 435         bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
 436         if (IS_ERR(bp)) {
 437                 err = PTR_ERR(bp);
 438                 return err;
 439         }
 440
 441         attr = bp->attr;
 442         decode_ctrl_reg(uctrl, &ctrl);
 443         err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr);
 444         if (err)
 445                 return err;
 446
 447         return modify_user_hw_breakpoint(bp, &attr);
 448 }
 449
 450 static int ptrace_hbp_set_addr(unsigned int note_type,
 451                                struct task_struct *tsk,
 452                                unsigned long idx,
 453                                u64 addr)
 454 {
 455         int err;
 456         struct perf_event *bp;
 457         struct perf_event_attr attr;
 458
 459         bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
 460         if (IS_ERR(bp)) {
 461                 err = PTR_ERR(bp);
 462                 return err;
 463         }
 464
 465         attr = bp->attr;
 466         attr.bp_addr = addr;
 467         err = modify_user_hw_breakpoint(bp, &attr);
 468         return err;
 469 }
 470
 471 #define PTRACE_HBP_ADDR_SZ      sizeof(u64)
 472 #define PTRACE_HBP_CTRL_SZ      sizeof(u32)
 473 #define PTRACE_HBP_PAD_SZ       sizeof(u32)
 474
 475 static int hw_break_get(struct task_struct *target,
 476                         const struct user_regset *regset,
 477                         unsigned int pos, unsigned int count,
 478                         void *kbuf, void __user *ubuf)
 479 {
 480         unsigned int note_type = regset->core_note_type;
 481         int ret, idx = 0, offset, limit;
 482         u32 info, ctrl;
 483         u64 addr;
 484
 485         /* Resource info */
 486         ret = ptrace_hbp_get_resource_info(note_type, &info);
 487         if (ret)
 488                 return ret;
 489
 490         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &info, 0,
 491                                   sizeof(info));
 492         if (ret)
 493                 return ret;
 494
 495         /* Pad */
 496         offset = offsetof(struct user_hwdebug_state, pad);
 497         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, offset,
 498                                        offset + PTRACE_HBP_PAD_SZ);
 499         if (ret)
 500                 return ret;
 501
 502         /* (address, ctrl) registers */
 503         offset = offsetof(struct user_hwdebug_state, dbg_regs);
 504         limit = regset->n * regset->size;
 505         while (count && offset < limit) {
 506                 ret = ptrace_hbp_get_addr(note_type, target, idx, &addr);
 507                 if (ret)
 508                         return ret;
 509                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &addr,
 510                                           offset, offset + PTRACE_HBP_ADDR_SZ);
 511                 if (ret)
 512                         return ret;
 513                 offset += PTRACE_HBP_ADDR_SZ;
 514
 515                 ret = ptrace_hbp_get_ctrl(note_type, target, idx, &ctrl);
 516                 if (ret)
 517                         return ret;
 518                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &ctrl,
 519                                           offset, offset + PTRACE_HBP_CTRL_SZ);
 520                 if (ret)
 521                         return ret;
 522                 offset += PTRACE_HBP_CTRL_SZ;
 523
 524                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 525                                                offset,
 526                                                offset + PTRACE_HBP_PAD_SZ);
 527                 if (ret)
 528                         return ret;
 529                 offset += PTRACE_HBP_PAD_SZ;
 530                 idx++;
 531         }
 532
 533         return 0;
 534 }
 535
 536 static int hw_break_set(struct task_struct *target,
 537                         const struct user_regset *regset,
 538                         unsigned int pos, unsigned int count,
 539                         const void *kbuf, const void __user *ubuf)
 540 {
 541         unsigned int note_type = regset->core_note_type;
 542         int ret, idx = 0, offset, limit;
 543         u32 ctrl;
 544         u64 addr;
 545
 546         /* Resource info and pad */
 547         offset = offsetof(struct user_hwdebug_state, dbg_regs);
 548         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, offset);
 549         if (ret)
 550                 return ret;
 551
 552         /* (address, ctrl) registers */
 553         limit = regset->n * regset->size;
 554         while (count && offset < limit) {
 555                 if (count < PTRACE_HBP_ADDR_SZ)
 556                         return -EINVAL;
 557                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
 558                                          offset, offset + PTRACE_HBP_ADDR_SZ);
 559                 if (ret)
 560                         return ret;
 561                 ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
 562                 if (ret)
 563                         return ret;
 564                 offset += PTRACE_HBP_ADDR_SZ;
 565
 566                 if (!count)
 567                         break;
 568                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
 569                                          offset, offset + PTRACE_HBP_CTRL_SZ);
 570                 if (ret)
 571                         return ret;
 572                 ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
 573                 if (ret)
 574                         return ret;
 575                 offset += PTRACE_HBP_CTRL_SZ;
 576
 577                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 578                                                 offset,
 579                                                 offset + PTRACE_HBP_PAD_SZ);
 580                 if (ret)
 581                         return ret;
 582                 offset += PTRACE_HBP_PAD_SZ;
 583                 idx++;
 584         }
 585
 586         return 0;
 587 }
 588 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
 589
 590 static int gpr_get(struct task_struct *target,
 591                    const struct user_regset *regset,
 592                    unsigned int pos, unsigned int count,
 593                    void *kbuf, void __user *ubuf)
 594 {
 595         struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
 596         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 597 }
 598
 599 static int gpr_set(struct task_struct *target, const struct user_regset *regset,
 600                    unsigned int pos, unsigned int count,
 601                    const void *kbuf, const void __user *ubuf)
 602 {
 603         int ret;
 604         struct user_pt_regs newregs = task_pt_regs(target)->user_regs;
 605
 606         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
 607         if (ret)
 608                 return ret;
 609
 610         if (!valid_user_regs(&newregs, target))
 611                 return -EINVAL;
 612
 613         task_pt_regs(target)->user_regs = newregs;
 614         return 0;
 615 }
 616
 617 /*
 618  * TODO: update fp accessors for lazy context switching (sync/flush hwstate)
 619  */
 620 static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 621                    unsigned int pos, unsigned int count,
 622                    void *kbuf, void __user *ubuf)
 623 {
 624         struct user_fpsimd_state *uregs;
 625         uregs = &target->thread.fpsimd_state.user_fpsimd;
 626         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 627 }
 628
 629 static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 630                    unsigned int pos, unsigned int count,
 631                    const void *kbuf, const void __user *ubuf)
 632 {
 633         int ret;
 634         struct user_fpsimd_state newstate =
 635                 target->thread.fpsimd_state.user_fpsimd;
 636
 637         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 638         if (ret)
 639                 return ret;
 640
 641         target->thread.fpsimd_state.user_fpsimd = newstate;
 642         fpsimd_flush_task_state(target);
 643         return ret;
 644 }
 645
 646 static int tls_get(struct task_struct *target, const struct user_regset *regset,
 647                    unsigned int pos, unsigned int count,
 648                    void *kbuf, void __user *ubuf)
 649 {
 650         unsigned long *tls = &target->thread.tp_value;
 651         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, tls, 0, -1);
 652 }
 653
 654 static int tls_set(struct task_struct *target, const struct user_regset *regset,
 655                    unsigned int pos, unsigned int count,
 656                    const void *kbuf, const void __user *ubuf)
 657 {
 658         int ret;
 659         unsigned long tls = target->thread.tp_value;
 660
 661         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 662         if (ret)
 663                 return ret;
 664
 665         target->thread.tp_value = tls;
 666         return ret;
 667 }
 668
 669 static int system_call_get(struct task_struct *target,
 670                            const struct user_regset *regset,
 671                            unsigned int pos, unsigned int count,
 672                            void *kbuf, void __user *ubuf)
 673 {
 674         int syscallno = task_pt_regs(target)->syscallno;
 675
 676         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 677                                    &syscallno, 0, -1);
 678 }
 679
 680 static int system_call_set(struct task_struct *target,
 681                            const struct user_regset *regset,
 682                            unsigned int pos, unsigned int count,
 683                            const void *kbuf, const void __user *ubuf)
 684 {
 685         int syscallno = task_pt_regs(target)->syscallno;
 686         int ret;
 687
 688         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
 689         if (ret)
 690                 return ret;
 691
 692         task_pt_regs(target)->syscallno = syscallno;
 693         return ret;
 694 }
 695
 696 enum aarch64_regset {
 697         REGSET_GPR,
 698         REGSET_FPR,
 699         REGSET_TLS,
 700 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 701         REGSET_HW_BREAK,
 702         REGSET_HW_WATCH,
 703 #endif
 704         REGSET_SYSTEM_CALL,
 705 };
 706
 707 static const struct user_regset aarch64_regsets[] = {
 708         [REGSET_GPR] = {
 709                 .core_note_type = NT_PRSTATUS,
 710                 .n = sizeof(struct user_pt_regs) / sizeof(u64),
 711                 .size = sizeof(u64),
 712                 .align = sizeof(u64),
 713                 .get = gpr_get,
 714                 .set = gpr_set
 715         },
 716         [REGSET_FPR] = {
 717                 .core_note_type = NT_PRFPREG,
 718                 .n = sizeof(struct user_fpsimd_state) / sizeof(u32),
 719                 /*
 720                  * We pretend we have 32-bit registers because the fpsr and
 721                  * fpcr are 32-bits wide.
 722                  */
 723                 .size = sizeof(u32),
 724                 .align = sizeof(u32),
 725                 .get = fpr_get,
 726                 .set = fpr_set
 727         },
 728         [REGSET_TLS] = {
 729                 .core_note_type = NT_ARM_TLS,
 730                 .n = 1,
 731                 .size = sizeof(void *),
 732                 .align = sizeof(void *),
 733                 .get = tls_get,
 734                 .set = tls_set,
 735         },
 736 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 737         [REGSET_HW_BREAK] = {
 738                 .core_note_type = NT_ARM_HW_BREAK,
 739                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 740                 .size = sizeof(u32),
 741                 .align = sizeof(u32),
 742                 .get = hw_break_get,
 743                 .set = hw_break_set,
 744         },
 745         [REGSET_HW_WATCH] = {
 746                 .core_note_type = NT_ARM_HW_WATCH,
 747                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 748                 .size = sizeof(u32),
 749                 .align = sizeof(u32),
 750                 .get = hw_break_get,
 751                 .set = hw_break_set,
 752         },
 753 #endif
 754         [REGSET_SYSTEM_CALL] = {
 755                 .core_note_type = NT_ARM_SYSTEM_CALL,
 756                 .n = 1,
 757                 .size = sizeof(int),
 758                 .align = sizeof(int),
 759                 .get = system_call_get,
 760                 .set = system_call_set,
 761         },
 762 };
 763
 764 static const struct user_regset_view user_aarch64_view = {
 765         .name = "aarch64", .e_machine = EM_AARCH64,
 766         .regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
 767 };
 768
 769 #ifdef CONFIG_COMPAT
 770 #include <linux/compat.h>
 771
 772 enum compat_regset {
 773         REGSET_COMPAT_GPR,
 774         REGSET_COMPAT_VFP,
 775 };
 776
 777 static int compat_gpr_get(struct task_struct *target,
 778                           const struct user_regset *regset,
 779                           unsigned int pos, unsigned int count,
 780                           void *kbuf, void __user *ubuf)
 781 {
 782         int ret = 0;
 783         unsigned int i, start, num_regs;
 784
 785         /* Calculate the number of AArch32 registers contained in count */
 786         num_regs = count / regset->size;
 787
 788         /* Convert pos into an register number */
 789         start = pos / regset->size;
 790
 791         if (start + num_regs > regset->n)
 792                 return -EIO;
 793
 794         for (i = 0; i < num_regs; ++i) {
 795                 unsigned int idx = start + i;
 796                 compat_ulong_t reg;
 797
 798                 switch (idx) {
 799                 case 15:
 800                         reg = task_pt_regs(target)->pc;
 801                         break;
 802                 case 16:
 803                         reg = task_pt_regs(target)->pstate;
 804                         break;
 805                 case 17:
 806                         reg = task_pt_regs(target)->orig_x0;
 807                         break;
 808                 default:
 809                         reg = task_pt_regs(target)->regs[idx];
 810                 }
 811
 812                 if (kbuf) {
 813                         memcpy(kbuf, &reg, sizeof(reg));
 814                         kbuf += sizeof(reg);
 815                 } else {
 816                         ret = copy_to_user(ubuf, &reg, sizeof(reg));
 817                         if (ret) {
 818                                 ret = -EFAULT;
 819                                 break;
 820                         }
 821
 822                         ubuf += sizeof(reg);
 823                 }
 824         }
 825
 826         return ret;
 827 }
 828
 829 static int compat_gpr_set(struct task_struct *target,
 830                           const struct user_regset *regset,
 831                           unsigned int pos, unsigned int count,
 832                           const void *kbuf, const void __user *ubuf)
 833 {
 834         struct pt_regs newregs;
 835         int ret = 0;
 836         unsigned int i, start, num_regs;
 837
 838         /* Calculate the number of AArch32 registers contained in count */
 839         num_regs = count / regset->size;
 840
 841         /* Convert pos into an register number */
 842         start = pos / regset->size;
 843
 844         if (start + num_regs > regset->n)
 845                 return -EIO;
 846
 847         newregs = *task_pt_regs(target);
 848
 849         for (i = 0; i < num_regs; ++i) {
 850                 unsigned int idx = start + i;
 851                 compat_ulong_t reg;
 852
 853                 if (kbuf) {
 854                         memcpy(&reg, kbuf, sizeof(reg));
 855                         kbuf += sizeof(reg);
 856                 } else {
 857                         ret = copy_from_user(&reg, ubuf, sizeof(reg));
 858                         if (ret) {
 859                                 ret = -EFAULT;
 860                                 break;
 861                         }
 862
 863                         ubuf += sizeof(reg);
 864                 }
 865
 866                 switch (idx) {
 867                 case 15:
 868                         newregs.pc = reg;
 869                         break;
 870                 case 16:
 871                         newregs.pstate = reg;
 872                         break;
 873                 case 17:
 874                         newregs.orig_x0 = reg;
 875                         break;
 876                 default:
 877                         newregs.regs[idx] = reg;
 878                 }
 879
 880         }
 881
 882         if (valid_user_regs(&newregs.user_regs, target))
 883                 *task_pt_regs(target) = newregs;
 884         else
 885                 ret = -EINVAL;
 886
 887         return ret;
 888 }
 889
 890 static int compat_vfp_get(struct task_struct *target,
 891                           const struct user_regset *regset,
 892                           unsigned int pos, unsigned int count,
 893                           void *kbuf, void __user *ubuf)
 894 {
 895         struct user_fpsimd_state *uregs;
 896         compat_ulong_t fpscr;
 897         int ret;
 898
 899         uregs = &target->thread.fpsimd_state.user_fpsimd;
 900
 901         /*
 902          * The VFP registers are packed into the fpsimd_state, so they all sit
 903          * nicely together for us. We just need to create the fpscr separately.
 904          */
 905         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0,
 906                                   VFP_STATE_SIZE - sizeof(compat_ulong_t));
 907
 908         if (count && !ret) {
 909                 fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
 910                         (uregs->fpcr & VFP_FPSCR_CTRL_MASK);
 911                 ret = put_user(fpscr, (compat_ulong_t *)ubuf);
 912         }
 913
 914         return ret;
 915 }
 916
 917 static int compat_vfp_set(struct task_struct *target,
 918                           const struct user_regset *regset,
 919                           unsigned int pos, unsigned int count,
 920                           const void *kbuf, const void __user *ubuf)
 921 {
 922         struct user_fpsimd_state *uregs;
 923         compat_ulong_t fpscr;
 924         int ret;
 925
 926         if (pos + count > VFP_STATE_SIZE)
 927                 return -EIO;
 928
 929         uregs = &target->thread.fpsimd_state.user_fpsimd;
 930
 931         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
 932                                  VFP_STATE_SIZE - sizeof(compat_ulong_t));
 933
 934         if (count && !ret) {
 935                 ret = get_user(fpscr, (compat_ulong_t *)ubuf);
 936                 uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
 937                 uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 938         }
 939
 940         fpsimd_flush_task_state(target);
 941         return ret;
 942 }
 943
 944 static int compat_tls_get(struct task_struct *target,
 945                           const struct user_regset *regset, unsigned int pos,
 946                           unsigned int count, void *kbuf, void __user *ubuf)
 947 {
 948         compat_ulong_t tls = (compat_ulong_t)target->thread.tp_value;
 949         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 950 }
 951
 952 static int compat_tls_set(struct task_struct *target,
 953                           const struct user_regset *regset, unsigned int pos,
 954                           unsigned int count, const void *kbuf,
 955                           const void __user *ubuf)
 956 {
 957         int ret;
 958         compat_ulong_t tls = target->thread.tp_value;
 959
 960         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 961         if (ret)
 962                 return ret;
 963
 964         target->thread.tp_value = tls;
 965         return ret;
 966 }
 967
 968 static const struct user_regset aarch32_regsets[] = {
 969         [REGSET_COMPAT_GPR] = {
 970                 .core_note_type = NT_PRSTATUS,
 971                 .n = COMPAT_ELF_NGREG,
 972                 .size = sizeof(compat_elf_greg_t),
 973                 .align = sizeof(compat_elf_greg_t),
 974                 .get = compat_gpr_get,
 975                 .set = compat_gpr_set
 976         },
 977         [REGSET_COMPAT_VFP] = {
 978                 .core_note_type = NT_ARM_VFP,
 979                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 980                 .size = sizeof(compat_ulong_t),
 981                 .align = sizeof(compat_ulong_t),
 982                 .get = compat_vfp_get,
 983                 .set = compat_vfp_set
 984         },
 985 };
 986
 987 static const struct user_regset_view user_aarch32_view = {
 988         .name = "aarch32", .e_machine = EM_ARM,
 989         .regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
 990 };
 991
 992 static const struct user_regset aarch32_ptrace_regsets[] = {
 993         [REGSET_GPR] = {
 994                 .core_note_type = NT_PRSTATUS,
 995                 .n = COMPAT_ELF_NGREG,
 996                 .size = sizeof(compat_elf_greg_t),
 997                 .align = sizeof(compat_elf_greg_t),
 998                 .get = compat_gpr_get,
 999                 .set = compat_gpr_set
1000         },
1001         [REGSET_FPR] = {
1002                 .core_note_type = NT_ARM_VFP,
1003                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
1004                 .size = sizeof(compat_ulong_t),
1005                 .align = sizeof(compat_ulong_t),
1006                 .get = compat_vfp_get,
1007                 .set = compat_vfp_set
1008         },
1009         [REGSET_TLS] = {
1010                 .core_note_type = NT_ARM_TLS,
1011                 .n = 1,
1012                 .size = sizeof(compat_ulong_t),
1013                 .align = sizeof(compat_ulong_t),
1014                 .get = compat_tls_get,
1015                 .set = compat_tls_set,
1016         },
1017 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1018         [REGSET_HW_BREAK] = {
1019                 .core_note_type = NT_ARM_HW_BREAK,
1020                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
1021                 .size = sizeof(u32),
1022                 .align = sizeof(u32),
1023                 .get = hw_break_get,
1024                 .set = hw_break_set,
1025         },
1026         [REGSET_HW_WATCH] = {
1027                 .core_note_type = NT_ARM_HW_WATCH,
1028                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
1029                 .size = sizeof(u32),
1030                 .align = sizeof(u32),
1031                 .get = hw_break_get,
1032                 .set = hw_break_set,
1033         },
1034 #endif
1035         [REGSET_SYSTEM_CALL] = {
1036                 .core_note_type = NT_ARM_SYSTEM_CALL,
1037                 .n = 1,
1038                 .size = sizeof(int),
1039                 .align = sizeof(int),
1040                 .get = system_call_get,
1041                 .set = system_call_set,
1042         },
1043 };
1044
1045 static const struct user_regset_view user_aarch32_ptrace_view = {
1046         .name = "aarch32", .e_machine = EM_ARM,
1047         .regsets = aarch32_ptrace_regsets, .n = ARRAY_SIZE(aarch32_ptrace_regsets)
1048 };
1049
1050 static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
1051                                    compat_ulong_t __user *ret)
1052 {
1053         compat_ulong_t tmp;
1054
1055         if (off & 3)
1056                 return -EIO;
1057
1058         if (off == COMPAT_PT_TEXT_ADDR)
1059                 tmp = tsk->mm->start_code;
1060         else if (off == COMPAT_PT_DATA_ADDR)
1061                 tmp = tsk->mm->start_data;
1062         else if (off == COMPAT_PT_TEXT_END_ADDR)
1063                 tmp = tsk->mm->end_code;
1064         else if (off < sizeof(compat_elf_gregset_t))
1065                 return copy_regset_to_user(tsk, &user_aarch32_view,
1066                                            REGSET_COMPAT_GPR, off,
1067                                            sizeof(compat_ulong_t), ret);
1068         else if (off >= COMPAT_USER_SZ)
1069                 return -EIO;
1070         else
1071                 tmp = 0;
1072
1073         return put_user(tmp, ret);
1074 }
1075
1076 static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
1077                                     compat_ulong_t val)
1078 {
1079         int ret;
1080         mm_segment_t old_fs = get_fs();
1081
1082         if (off & 3 || off >= COMPAT_USER_SZ)
1083                 return -EIO;
1084
1085         if (off >= sizeof(compat_elf_gregset_t))
1086                 return 0;
1087
1088         set_fs(KERNEL_DS);
1089         ret = copy_regset_from_user(tsk, &user_aarch32_view,
1090                                     REGSET_COMPAT_GPR, off,
1091                                     sizeof(compat_ulong_t),
1092                                     &val);
1093         set_fs(old_fs);
1094
1095         return ret;
1096 }
1097
1098 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1099
1100 /*
1101  * Convert a virtual register number into an index for a thread_info
1102  * breakpoint array. Breakpoints are identified using positive numbers
1103  * whilst watchpoints are negative. The registers are laid out as pairs
1104  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
1105  * Register 0 is reserved for describing resource information.
1106  */
1107 static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
1108 {
1109         return (abs(num) - 1) >> 1;
1110 }
1111
1112 static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
1113 {
1114         u8 num_brps, num_wrps, debug_arch, wp_len;
1115         u32 reg = 0;
1116
1117         num_brps        = hw_breakpoint_slots(TYPE_INST);
1118         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
1119
1120         debug_arch      = debug_monitors_arch();
1121         wp_len          = 8;
1122         reg             |= debug_arch;
1123         reg             <<= 8;
1124         reg             |= wp_len;
1125         reg             <<= 8;
1126         reg             |= num_wrps;
1127         reg             <<= 8;
1128         reg             |= num_brps;
1129
1130         *kdata = reg;
1131         return 0;
1132 }
1133
1134 static int compat_ptrace_hbp_get(unsigned int note_type,
1135                                  struct task_struct *tsk,
1136                                  compat_long_t num,
1137                                  u32 *kdata)
1138 {
1139         u64 addr = 0;
1140         u32 ctrl = 0;
1141
1142         int err, idx = compat_ptrace_hbp_num_to_idx(num);;
1143
1144         if (num & 1) {
1145                 err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
1146                 *kdata = (u32)addr;
1147         } else {
1148                 err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
1149                 *kdata = ctrl;
1150         }
1151
1152         return err;
1153 }
1154
1155 static int compat_ptrace_hbp_set(unsigned int note_type,
1156                                  struct task_struct *tsk,
1157                                  compat_long_t num,
1158                                  u32 *kdata)
1159 {
1160         u64 addr;
1161         u32 ctrl;
1162
1163         int err, idx = compat_ptrace_hbp_num_to_idx(num);
1164
1165         if (num & 1) {
1166                 addr = *kdata;
1167                 err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
1168         } else {
1169                 ctrl = *kdata;
1170                 err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
1171         }
1172
1173         return err;
1174 }
1175
1176 static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
1177                                     compat_ulong_t __user *data)
1178 {
1179         int ret;
1180         u32 kdata;
1181         mm_segment_t old_fs = get_fs();
1182
1183         set_fs(KERNEL_DS);
1184         /* Watchpoint */
1185         if (num < 0) {
1186                 ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
1187         /* Resource info */
1188         } else if (num == 0) {
1189                 ret = compat_ptrace_hbp_get_resource_info(&kdata);
1190         /* Breakpoint */
1191         } else {
1192                 ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
1193         }
1194         set_fs(old_fs);
1195
1196         if (!ret)
1197                 ret = put_user(kdata, data);
1198
1199         return ret;
1200 }
1201
1202 static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
1203                                     compat_ulong_t __user *data)
1204 {
1205         int ret;
1206         u32 kdata = 0;
1207         mm_segment_t old_fs = get_fs();
1208
1209         if (num == 0)
1210                 return 0;
1211
1212         ret = get_user(kdata, data);
1213         if (ret)
1214                 return ret;
1215
1216         set_fs(KERNEL_DS);
1217         if (num < 0)
1218                 ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
1219         else
1220                 ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
1221         set_fs(old_fs);
1222
1223         return ret;
1224 }
1225 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
1226
1227 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1228                         compat_ulong_t caddr, compat_ulong_t cdata)
1229 {
1230         unsigned long addr = caddr;
1231         unsigned long data = cdata;
1232         void __user *datap = compat_ptr(data);
1233         int ret;
1234
1235         switch (request) {
1236                 case PTRACE_PEEKUSR:
1237                         ret = compat_ptrace_read_user(child, addr, datap);
1238                         break;
1239
1240                 case PTRACE_POKEUSR:
1241                         ret = compat_ptrace_write_user(child, addr, data);
1242                         break;
1243
1244                 case COMPAT_PTRACE_GETREGS:
1245                         ret = copy_regset_to_user(child,
1246                                                   &user_aarch32_view,
1247                                                   REGSET_COMPAT_GPR,
1248                                                   0, sizeof(compat_elf_gregset_t),
1249                                                   datap);
1250                         break;
1251
1252                 case COMPAT_PTRACE_SETREGS:
1253                         ret = copy_regset_from_user(child,
1254                                                     &user_aarch32_view,
1255                                                     REGSET_COMPAT_GPR,
1256                                                     0, sizeof(compat_elf_gregset_t),
1257                                                     datap);
1258                         break;
1259
1260                 case COMPAT_PTRACE_GET_THREAD_AREA:
1261                         ret = put_user((compat_ulong_t)child->thread.tp_value,
1262                                        (compat_ulong_t __user *)datap);
1263                         break;
1264
1265                 case COMPAT_PTRACE_SET_SYSCALL:
1266                         task_pt_regs(child)->syscallno = data;
1267                         ret = 0;
1268                         break;
1269
1270                 case COMPAT_PTRACE_GETVFPREGS:
1271                         ret = copy_regset_to_user(child,
1272                                                   &user_aarch32_view,
1273                                                   REGSET_COMPAT_VFP,
1274                                                   0, VFP_STATE_SIZE,
1275                                                   datap);
1276                         break;
1277
1278                 case COMPAT_PTRACE_SETVFPREGS:
1279                         ret = copy_regset_from_user(child,
1280                                                     &user_aarch32_view,
1281                                                     REGSET_COMPAT_VFP,
1282                                                     0, VFP_STATE_SIZE,
1283                                                     datap);
1284                         break;
1285
1286 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1287                 case COMPAT_PTRACE_GETHBPREGS:
1288                         ret = compat_ptrace_gethbpregs(child, addr, datap);
1289                         break;
1290
1291                 case COMPAT_PTRACE_SETHBPREGS:
1292                         ret = compat_ptrace_sethbpregs(child, addr, datap);
1293                         break;
1294 #endif
1295
1296                 default:
1297                         ret = compat_ptrace_request(child, request, addr,
1298                                                     data);
1299                         break;
1300         }
1301
1302         return ret;
1303 }
1304 #endif /* CONFIG_COMPAT */
1305
1306 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1307 {
1308 #ifdef CONFIG_COMPAT
1309         /*
1310          * Core dumping of 32-bit tasks or compat ptrace requests must use the
1311          * user_aarch32_view compatible with arm32. Native ptrace requests on
1312          * 32-bit children use an extended user_aarch32_ptrace_view to allow
1313          * access to the TLS register.
1314          */
1315         if (is_compat_task())
1316                 return &user_aarch32_view;
1317         else if (is_compat_thread(task_thread_info(task)))
1318                 return &user_aarch32_ptrace_view;
1319 #endif
1320         return &user_aarch64_view;
1321 }
1322
1323 long arch_ptrace(struct task_struct *child, long request,
1324                  unsigned long addr, unsigned long data)
1325 {
1326         return ptrace_request(child, request, addr, data);
1327 }
1328
1329 enum ptrace_syscall_dir {
1330         PTRACE_SYSCALL_ENTER = 0,
1331         PTRACE_SYSCALL_EXIT,
1332 };
1333
1334 static void tracehook_report_syscall(struct pt_regs *regs,
1335                                      enum ptrace_syscall_dir dir)
1336 {
1337         int regno;
1338         unsigned long saved_reg;
1339
1340         /*
1341          * A scratch register (ip(r12) on AArch32, x7 on AArch64) is
1342          * used to denote syscall entry/exit:
1343          */
1344         regno = (is_compat_task() ? 12 : 7);
1345         saved_reg = regs->regs[regno];
1346         regs->regs[regno] = dir;
1347
1348         if (dir == PTRACE_SYSCALL_EXIT)
1349                 tracehook_report_syscall_exit(regs, 0);
1350         else if (tracehook_report_syscall_entry(regs))
1351                 regs->syscallno = ~0UL;
1352
1353         regs->regs[regno] = saved_reg;
1354 }
1355
1356 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
1357 {
1358         if (test_thread_flag(TIF_SYSCALL_TRACE))
1359                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
1360
1361         /* Do the secure computing after ptrace; failures should be fast. */
1362         if (secure_computing(NULL) == -1)
1363                 return -1;
1364
1365         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1366                 trace_sys_enter(regs, regs->syscallno);
1367
1368         audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
1369                             regs->regs[2], regs->regs[3]);
1370
1371         return regs->syscallno;
1372 }
1373
1374 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
1375 {
1376         audit_syscall_exit(regs);
1377
1378         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1379                 trace_sys_exit(regs, regs_return_value(regs));
1380
1381         if (test_thread_flag(TIF_SYSCALL_TRACE))
1382                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
1383 }
1384
1385 /*
1386  * Bits which are always architecturally RES0 per ARM DDI 0487A.h
1387  * Userspace cannot use these until they have an architectural meaning.
1388  * We also reserve IL for the kernel; SS is handled dynamically.
1389  */
1390 #define SPSR_EL1_AARCH64_RES0_BITS \
1391         (GENMASK_ULL(63,32) | GENMASK_ULL(27, 22) | GENMASK_ULL(20, 10) | \
1392          GENMASK_ULL(5, 5))
1393 #define SPSR_EL1_AARCH32_RES0_BITS \
1394         (GENMASK_ULL(63,32) | GENMASK_ULL(24, 22) | GENMASK_ULL(20,20))
1395
1396 static int valid_compat_regs(struct user_pt_regs *regs)
1397 {
1398         regs->pstate &= ~SPSR_EL1_AARCH32_RES0_BITS;
1399
1400         if (!system_supports_mixed_endian_el0()) {
1401                 if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
1402                         regs->pstate |= COMPAT_PSR_E_BIT;
1403                 else
1404                         regs->pstate &= ~COMPAT_PSR_E_BIT;
1405         }
1406
1407         if (user_mode(regs) && (regs->pstate & PSR_MODE32_BIT) &&
1408             (regs->pstate & COMPAT_PSR_A_BIT) == 0 &&
1409             (regs->pstate & COMPAT_PSR_I_BIT) == 0 &&
1410             (regs->pstate & COMPAT_PSR_F_BIT) == 0) {
1411                 return 1;
1412         }
1413
1414         /*
1415          * Force PSR to a valid 32-bit EL0t, preserving the same bits as
1416          * arch/arm.
1417          */
1418         regs->pstate &= COMPAT_PSR_N_BIT | COMPAT_PSR_Z_BIT |
1419                         COMPAT_PSR_C_BIT | COMPAT_PSR_V_BIT |
1420                         COMPAT_PSR_Q_BIT | COMPAT_PSR_IT_MASK |
1421                         COMPAT_PSR_GE_MASK | COMPAT_PSR_E_BIT |
1422                         COMPAT_PSR_T_BIT;
1423         regs->pstate |= PSR_MODE32_BIT;
1424
1425         return 0;
1426 }
1427
1428 static int valid_native_regs(struct user_pt_regs *regs)
1429 {
1430         regs->pstate &= ~SPSR_EL1_AARCH64_RES0_BITS;
1431
1432         if (user_mode(regs) && !(regs->pstate & PSR_MODE32_BIT) &&
1433             (regs->pstate & PSR_D_BIT) == 0 &&
1434             (regs->pstate & PSR_A_BIT) == 0 &&
1435             (regs->pstate & PSR_I_BIT) == 0 &&
1436             (regs->pstate & PSR_F_BIT) == 0) {
1437                 return 1;
1438         }
1439
1440         /* Force PSR to a valid 64-bit EL0t */
1441         regs->pstate &= PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT;
1442
1443         return 0;
1444 }
1445
1446 /*
1447  * Are the current registers suitable for user mode? (used to maintain
1448  * security in signal handlers)
1449  */
1450 int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task)
1451 {
1452         if (!test_tsk_thread_flag(task, TIF_SINGLESTEP))
1453                 regs->pstate &= ~DBG_SPSR_SS;
1454
1455         if (is_compat_thread(task_thread_info(task)))
1456                 return valid_compat_regs(regs);
1457         else
1458                 return valid_native_regs(regs);
1459 }