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