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;
 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
 530         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 531         if (ret)
 532                 return ret;
 533
 534         target->thread.fpsimd_state.user_fpsimd = newstate;
 535         fpsimd_flush_task_state(target);
 536         return ret;
 537 }
 538
 539 static int tls_get(struct task_struct *target, const struct user_regset *regset,
 540                    unsigned int pos, unsigned int count,
 541                    void *kbuf, void __user *ubuf)
 542 {
 543         unsigned long *tls = &target->thread.tp_value;
 544         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, tls, 0, -1);
 545 }
 546
 547 static int tls_set(struct task_struct *target, const struct user_regset *regset,
 548                    unsigned int pos, unsigned int count,
 549                    const void *kbuf, const void __user *ubuf)
 550 {
 551         int ret;
 552         unsigned long tls;
 553
 554         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 555         if (ret)
 556                 return ret;
 557
 558         target->thread.tp_value = tls;
 559         return ret;
 560 }
 561
 562 static int system_call_get(struct task_struct *target,
 563                            const struct user_regset *regset,
 564                            unsigned int pos, unsigned int count,
 565                            void *kbuf, void __user *ubuf)
 566 {
 567         int syscallno = task_pt_regs(target)->syscallno;
 568
 569         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 570                                    &syscallno, 0, -1);
 571 }
 572
 573 static int system_call_set(struct task_struct *target,
 574                            const struct user_regset *regset,
 575                            unsigned int pos, unsigned int count,
 576                            const void *kbuf, const void __user *ubuf)
 577 {
 578         int syscallno, ret;
 579
 580         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
 581         if (ret)
 582                 return ret;
 583
 584         task_pt_regs(target)->syscallno = syscallno;
 585         return ret;
 586 }
 587
 588 enum aarch64_regset {
 589         REGSET_GPR,
 590         REGSET_FPR,
 591         REGSET_TLS,
 592 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 593         REGSET_HW_BREAK,
 594         REGSET_HW_WATCH,
 595 #endif
 596         REGSET_SYSTEM_CALL,
 597 };
 598
 599 static const struct user_regset aarch64_regsets[] = {
 600         [REGSET_GPR] = {
 601                 .core_note_type = NT_PRSTATUS,
 602                 .n = sizeof(struct user_pt_regs) / sizeof(u64),
 603                 .size = sizeof(u64),
 604                 .align = sizeof(u64),
 605                 .get = gpr_get,
 606                 .set = gpr_set
 607         },
 608         [REGSET_FPR] = {
 609                 .core_note_type = NT_PRFPREG,
 610                 .n = sizeof(struct user_fpsimd_state) / sizeof(u32),
 611                 /*
 612                  * We pretend we have 32-bit registers because the fpsr and
 613                  * fpcr are 32-bits wide.
 614                  */
 615                 .size = sizeof(u32),
 616                 .align = sizeof(u32),
 617                 .get = fpr_get,
 618                 .set = fpr_set
 619         },
 620         [REGSET_TLS] = {
 621                 .core_note_type = NT_ARM_TLS,
 622                 .n = 1,
 623                 .size = sizeof(void *),
 624                 .align = sizeof(void *),
 625                 .get = tls_get,
 626                 .set = tls_set,
 627         },
 628 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 629         [REGSET_HW_BREAK] = {
 630                 .core_note_type = NT_ARM_HW_BREAK,
 631                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 632                 .size = sizeof(u32),
 633                 .align = sizeof(u32),
 634                 .get = hw_break_get,
 635                 .set = hw_break_set,
 636         },
 637         [REGSET_HW_WATCH] = {
 638                 .core_note_type = NT_ARM_HW_WATCH,
 639                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 640                 .size = sizeof(u32),
 641                 .align = sizeof(u32),
 642                 .get = hw_break_get,
 643                 .set = hw_break_set,
 644         },
 645 #endif
 646         [REGSET_SYSTEM_CALL] = {
 647                 .core_note_type = NT_ARM_SYSTEM_CALL,
 648                 .n = 1,
 649                 .size = sizeof(int),
 650                 .align = sizeof(int),
 651                 .get = system_call_get,
 652                 .set = system_call_set,
 653         },
 654 };
 655
 656 static const struct user_regset_view user_aarch64_view = {
 657         .name = "aarch64", .e_machine = EM_AARCH64,
 658         .regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
 659 };
 660
 661 #ifdef CONFIG_COMPAT
 662 #include <linux/compat.h>
 663
 664 enum compat_regset {
 665         REGSET_COMPAT_GPR,
 666         REGSET_COMPAT_VFP,
 667 };
 668
 669 static int compat_gpr_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 ret = 0;
 675         unsigned int i, start, num_regs;
 676
 677         /* Calculate the number of AArch32 registers contained in count */
 678         num_regs = count / regset->size;
 679
 680         /* Convert pos into an register number */
 681         start = pos / regset->size;
 682
 683         if (start + num_regs > regset->n)
 684                 return -EIO;
 685
 686         for (i = 0; i < num_regs; ++i) {
 687                 unsigned int idx = start + i;
 688                 compat_ulong_t reg;
 689
 690                 switch (idx) {
 691                 case 15:
 692                         reg = task_pt_regs(target)->pc;
 693                         break;
 694                 case 16:
 695                         reg = task_pt_regs(target)->pstate;
 696                         break;
 697                 case 17:
 698                         reg = task_pt_regs(target)->orig_x0;
 699                         break;
 700                 default:
 701                         reg = task_pt_regs(target)->regs[idx];
 702                 }
 703
 704                 if (kbuf) {
 705                         memcpy(kbuf, &reg, sizeof(reg));
 706                         kbuf += sizeof(reg);
 707                 } else {
 708                         ret = copy_to_user(ubuf, &reg, sizeof(reg));
 709                         if (ret) {
 710                                 ret = -EFAULT;
 711                                 break;
 712                         }
 713
 714                         ubuf += sizeof(reg);
 715                 }
 716         }
 717
 718         return ret;
 719 }
 720
 721 static int compat_gpr_set(struct task_struct *target,
 722                           const struct user_regset *regset,
 723                           unsigned int pos, unsigned int count,
 724                           const void *kbuf, const void __user *ubuf)
 725 {
 726         struct pt_regs newregs;
 727         int ret = 0;
 728         unsigned int i, start, num_regs;
 729
 730         /* Calculate the number of AArch32 registers contained in count */
 731         num_regs = count / regset->size;
 732
 733         /* Convert pos into an register number */
 734         start = pos / regset->size;
 735
 736         if (start + num_regs > regset->n)
 737                 return -EIO;
 738
 739         newregs = *task_pt_regs(target);
 740
 741         for (i = 0; i < num_regs; ++i) {
 742                 unsigned int idx = start + i;
 743                 compat_ulong_t reg;
 744
 745                 if (kbuf) {
 746                         memcpy(&reg, kbuf, sizeof(reg));
 747                         kbuf += sizeof(reg);
 748                 } else {
 749                         ret = copy_from_user(&reg, ubuf, sizeof(reg));
 750                         if (ret) {
 751                                 ret = -EFAULT;
 752                                 break;
 753                         }
 754
 755                         ubuf += sizeof(reg);
 756                 }
 757
 758                 switch (idx) {
 759                 case 15:
 760                         newregs.pc = reg;
 761                         break;
 762                 case 16:
 763                         newregs.pstate = reg;
 764                         break;
 765                 case 17:
 766                         newregs.orig_x0 = reg;
 767                         break;
 768                 default:
 769                         newregs.regs[idx] = reg;
 770                 }
 771
 772         }
 773
 774         if (valid_user_regs(&newregs.user_regs, target))
 775                 *task_pt_regs(target) = newregs;
 776         else
 777                 ret = -EINVAL;
 778
 779         return ret;
 780 }
 781
 782 static int compat_vfp_get(struct task_struct *target,
 783                           const struct user_regset *regset,
 784                           unsigned int pos, unsigned int count,
 785                           void *kbuf, void __user *ubuf)
 786 {
 787         struct user_fpsimd_state *uregs;
 788         compat_ulong_t fpscr;
 789         int ret;
 790
 791         uregs = &target->thread.fpsimd_state.user_fpsimd;
 792
 793         /*
 794          * The VFP registers are packed into the fpsimd_state, so they all sit
 795          * nicely together for us. We just need to create the fpscr separately.
 796          */
 797         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0,
 798                                   VFP_STATE_SIZE - sizeof(compat_ulong_t));
 799
 800         if (count && !ret) {
 801                 fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
 802                         (uregs->fpcr & VFP_FPSCR_CTRL_MASK);
 803                 ret = put_user(fpscr, (compat_ulong_t *)ubuf);
 804         }
 805
 806         return ret;
 807 }
 808
 809 static int compat_vfp_set(struct task_struct *target,
 810                           const struct user_regset *regset,
 811                           unsigned int pos, unsigned int count,
 812                           const void *kbuf, const void __user *ubuf)
 813 {
 814         struct user_fpsimd_state *uregs;
 815         compat_ulong_t fpscr;
 816         int ret;
 817
 818         if (pos + count > VFP_STATE_SIZE)
 819                 return -EIO;
 820
 821         uregs = &target->thread.fpsimd_state.user_fpsimd;
 822
 823         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
 824                                  VFP_STATE_SIZE - sizeof(compat_ulong_t));
 825
 826         if (count && !ret) {
 827                 ret = get_user(fpscr, (compat_ulong_t *)ubuf);
 828                 uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
 829                 uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 830         }
 831
 832         fpsimd_flush_task_state(target);
 833         return ret;
 834 }
 835
 836 static int compat_tls_get(struct task_struct *target,
 837                           const struct user_regset *regset, unsigned int pos,
 838                           unsigned int count, void *kbuf, void __user *ubuf)
 839 {
 840         compat_ulong_t tls = (compat_ulong_t)target->thread.tp_value;
 841         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 842 }
 843
 844 static int compat_tls_set(struct task_struct *target,
 845                           const struct user_regset *regset, unsigned int pos,
 846                           unsigned int count, const void *kbuf,
 847                           const void __user *ubuf)
 848 {
 849         int ret;
 850         compat_ulong_t tls;
 851
 852         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 853         if (ret)
 854                 return ret;
 855
 856         target->thread.tp_value = tls;
 857         return ret;
 858 }
 859
 860 static const struct user_regset aarch32_regsets[] = {
 861         [REGSET_COMPAT_GPR] = {
 862                 .core_note_type = NT_PRSTATUS,
 863                 .n = COMPAT_ELF_NGREG,
 864                 .size = sizeof(compat_elf_greg_t),
 865                 .align = sizeof(compat_elf_greg_t),
 866                 .get = compat_gpr_get,
 867                 .set = compat_gpr_set
 868         },
 869         [REGSET_COMPAT_VFP] = {
 870                 .core_note_type = NT_ARM_VFP,
 871                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 872                 .size = sizeof(compat_ulong_t),
 873                 .align = sizeof(compat_ulong_t),
 874                 .get = compat_vfp_get,
 875                 .set = compat_vfp_set
 876         },
 877 };
 878
 879 static const struct user_regset_view user_aarch32_view = {
 880         .name = "aarch32", .e_machine = EM_ARM,
 881         .regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
 882 };
 883
 884 static const struct user_regset aarch32_ptrace_regsets[] = {
 885         [REGSET_GPR] = {
 886                 .core_note_type = NT_PRSTATUS,
 887                 .n = COMPAT_ELF_NGREG,
 888                 .size = sizeof(compat_elf_greg_t),
 889                 .align = sizeof(compat_elf_greg_t),
 890                 .get = compat_gpr_get,
 891                 .set = compat_gpr_set
 892         },
 893         [REGSET_FPR] = {
 894                 .core_note_type = NT_ARM_VFP,
 895                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 896                 .size = sizeof(compat_ulong_t),
 897                 .align = sizeof(compat_ulong_t),
 898                 .get = compat_vfp_get,
 899                 .set = compat_vfp_set
 900         },
 901         [REGSET_TLS] = {
 902                 .core_note_type = NT_ARM_TLS,
 903                 .n = 1,
 904                 .size = sizeof(compat_ulong_t),
 905                 .align = sizeof(compat_ulong_t),
 906                 .get = compat_tls_get,
 907                 .set = compat_tls_set,
 908         },
 909 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 910         [REGSET_HW_BREAK] = {
 911                 .core_note_type = NT_ARM_HW_BREAK,
 912                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 913                 .size = sizeof(u32),
 914                 .align = sizeof(u32),
 915                 .get = hw_break_get,
 916                 .set = hw_break_set,
 917         },
 918         [REGSET_HW_WATCH] = {
 919                 .core_note_type = NT_ARM_HW_WATCH,
 920                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 921                 .size = sizeof(u32),
 922                 .align = sizeof(u32),
 923                 .get = hw_break_get,
 924                 .set = hw_break_set,
 925         },
 926 #endif
 927         [REGSET_SYSTEM_CALL] = {
 928                 .core_note_type = NT_ARM_SYSTEM_CALL,
 929                 .n = 1,
 930                 .size = sizeof(int),
 931                 .align = sizeof(int),
 932                 .get = system_call_get,
 933                 .set = system_call_set,
 934         },
 935 };
 936
 937 static const struct user_regset_view user_aarch32_ptrace_view = {
 938         .name = "aarch32", .e_machine = EM_ARM,
 939         .regsets = aarch32_ptrace_regsets, .n = ARRAY_SIZE(aarch32_ptrace_regsets)
 940 };
 941
 942 static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
 943                                    compat_ulong_t __user *ret)
 944 {
 945         compat_ulong_t tmp;
 946
 947         if (off & 3)
 948                 return -EIO;
 949
 950         if (off == COMPAT_PT_TEXT_ADDR)
 951                 tmp = tsk->mm->start_code;
 952         else if (off == COMPAT_PT_DATA_ADDR)
 953                 tmp = tsk->mm->start_data;
 954         else if (off == COMPAT_PT_TEXT_END_ADDR)
 955                 tmp = tsk->mm->end_code;
 956         else if (off < sizeof(compat_elf_gregset_t))
 957                 return copy_regset_to_user(tsk, &user_aarch32_view,
 958                                            REGSET_COMPAT_GPR, off,
 959                                            sizeof(compat_ulong_t), ret);
 960         else if (off >= COMPAT_USER_SZ)
 961                 return -EIO;
 962         else
 963                 tmp = 0;
 964
 965         return put_user(tmp, ret);
 966 }
 967
 968 static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
 969                                     compat_ulong_t val)
 970 {
 971         int ret;
 972         mm_segment_t old_fs = get_fs();
 973
 974         if (off & 3 || off >= COMPAT_USER_SZ)
 975                 return -EIO;
 976
 977         if (off >= sizeof(compat_elf_gregset_t))
 978                 return 0;
 979
 980         set_fs(KERNEL_DS);
 981         ret = copy_regset_from_user(tsk, &user_aarch32_view,
 982                                     REGSET_COMPAT_GPR, off,
 983                                     sizeof(compat_ulong_t),
 984                                     &val);
 985         set_fs(old_fs);
 986
 987         return ret;
 988 }
 989
 990 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 991
 992 /*
 993  * Convert a virtual register number into an index for a thread_info
 994  * breakpoint array. Breakpoints are identified using positive numbers
 995  * whilst watchpoints are negative. The registers are laid out as pairs
 996  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 997  * Register 0 is reserved for describing resource information.
 998  */
 999 static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
1000 {
1001         return (abs(num) - 1) >> 1;
1002 }
1003
1004 static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
1005 {
1006         u8 num_brps, num_wrps, debug_arch, wp_len;
1007         u32 reg = 0;
1008
1009         num_brps        = hw_breakpoint_slots(TYPE_INST);
1010         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
1011
1012         debug_arch      = debug_monitors_arch();
1013         wp_len          = 8;
1014         reg             |= debug_arch;
1015         reg             <<= 8;
1016         reg             |= wp_len;
1017         reg             <<= 8;
1018         reg             |= num_wrps;
1019         reg             <<= 8;
1020         reg             |= num_brps;
1021
1022         *kdata = reg;
1023         return 0;
1024 }
1025
1026 static int compat_ptrace_hbp_get(unsigned int note_type,
1027                                  struct task_struct *tsk,
1028                                  compat_long_t num,
1029                                  u32 *kdata)
1030 {
1031         u64 addr = 0;
1032         u32 ctrl = 0;
1033
1034         int err, idx = compat_ptrace_hbp_num_to_idx(num);;
1035
1036         if (num & 1) {
1037                 err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
1038                 *kdata = (u32)addr;
1039         } else {
1040                 err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
1041                 *kdata = ctrl;
1042         }
1043
1044         return err;
1045 }
1046
1047 static int compat_ptrace_hbp_set(unsigned int note_type,
1048                                  struct task_struct *tsk,
1049                                  compat_long_t num,
1050                                  u32 *kdata)
1051 {
1052         u64 addr;
1053         u32 ctrl;
1054
1055         int err, idx = compat_ptrace_hbp_num_to_idx(num);
1056
1057         if (num & 1) {
1058                 addr = *kdata;
1059                 err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
1060         } else {
1061                 ctrl = *kdata;
1062                 err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
1063         }
1064
1065         return err;
1066 }
1067
1068 static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
1069                                     compat_ulong_t __user *data)
1070 {
1071         int ret;
1072         u32 kdata;
1073         mm_segment_t old_fs = get_fs();
1074
1075         set_fs(KERNEL_DS);
1076         /* Watchpoint */
1077         if (num < 0) {
1078                 ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
1079         /* Resource info */
1080         } else if (num == 0) {
1081                 ret = compat_ptrace_hbp_get_resource_info(&kdata);
1082         /* Breakpoint */
1083         } else {
1084                 ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
1085         }
1086         set_fs(old_fs);
1087
1088         if (!ret)
1089                 ret = put_user(kdata, data);
1090
1091         return ret;
1092 }
1093
1094 static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
1095                                     compat_ulong_t __user *data)
1096 {
1097         int ret;
1098         u32 kdata = 0;
1099         mm_segment_t old_fs = get_fs();
1100
1101         if (num == 0)
1102                 return 0;
1103
1104         ret = get_user(kdata, data);
1105         if (ret)
1106                 return ret;
1107
1108         set_fs(KERNEL_DS);
1109         if (num < 0)
1110                 ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
1111         else
1112                 ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
1113         set_fs(old_fs);
1114
1115         return ret;
1116 }
1117 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
1118
1119 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1120                         compat_ulong_t caddr, compat_ulong_t cdata)
1121 {
1122         unsigned long addr = caddr;
1123         unsigned long data = cdata;
1124         void __user *datap = compat_ptr(data);
1125         int ret;
1126
1127         switch (request) {
1128                 case PTRACE_PEEKUSR:
1129                         ret = compat_ptrace_read_user(child, addr, datap);
1130                         break;
1131
1132                 case PTRACE_POKEUSR:
1133                         ret = compat_ptrace_write_user(child, addr, data);
1134                         break;
1135
1136                 case COMPAT_PTRACE_GETREGS:
1137                         ret = copy_regset_to_user(child,
1138                                                   &user_aarch32_view,
1139                                                   REGSET_COMPAT_GPR,
1140                                                   0, sizeof(compat_elf_gregset_t),
1141                                                   datap);
1142                         break;
1143
1144                 case COMPAT_PTRACE_SETREGS:
1145                         ret = copy_regset_from_user(child,
1146                                                     &user_aarch32_view,
1147                                                     REGSET_COMPAT_GPR,
1148                                                     0, sizeof(compat_elf_gregset_t),
1149                                                     datap);
1150                         break;
1151
1152                 case COMPAT_PTRACE_GET_THREAD_AREA:
1153                         ret = put_user((compat_ulong_t)child->thread.tp_value,
1154                                        (compat_ulong_t __user *)datap);
1155                         break;
1156
1157                 case COMPAT_PTRACE_SET_SYSCALL:
1158                         task_pt_regs(child)->syscallno = data;
1159                         ret = 0;
1160                         break;
1161
1162                 case COMPAT_PTRACE_GETVFPREGS:
1163                         ret = copy_regset_to_user(child,
1164                                                   &user_aarch32_view,
1165                                                   REGSET_COMPAT_VFP,
1166                                                   0, VFP_STATE_SIZE,
1167                                                   datap);
1168                         break;
1169
1170                 case COMPAT_PTRACE_SETVFPREGS:
1171                         ret = copy_regset_from_user(child,
1172                                                     &user_aarch32_view,
1173                                                     REGSET_COMPAT_VFP,
1174                                                     0, VFP_STATE_SIZE,
1175                                                     datap);
1176                         break;
1177
1178 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1179                 case COMPAT_PTRACE_GETHBPREGS:
1180                         ret = compat_ptrace_gethbpregs(child, addr, datap);
1181                         break;
1182
1183                 case COMPAT_PTRACE_SETHBPREGS:
1184                         ret = compat_ptrace_sethbpregs(child, addr, datap);
1185                         break;
1186 #endif
1187
1188                 default:
1189                         ret = compat_ptrace_request(child, request, addr,
1190                                                     data);
1191                         break;
1192         }
1193
1194         return ret;
1195 }
1196 #endif /* CONFIG_COMPAT */
1197
1198 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1199 {
1200 #ifdef CONFIG_COMPAT
1201         /*
1202          * Core dumping of 32-bit tasks or compat ptrace requests must use the
1203          * user_aarch32_view compatible with arm32. Native ptrace requests on
1204          * 32-bit children use an extended user_aarch32_ptrace_view to allow
1205          * access to the TLS register.
1206          */
1207         if (is_compat_task())
1208                 return &user_aarch32_view;
1209         else if (is_compat_thread(task_thread_info(task)))
1210                 return &user_aarch32_ptrace_view;
1211 #endif
1212         return &user_aarch64_view;
1213 }
1214
1215 long arch_ptrace(struct task_struct *child, long request,
1216                  unsigned long addr, unsigned long data)
1217 {
1218         return ptrace_request(child, request, addr, data);
1219 }
1220
1221 enum ptrace_syscall_dir {
1222         PTRACE_SYSCALL_ENTER = 0,
1223         PTRACE_SYSCALL_EXIT,
1224 };
1225
1226 static void tracehook_report_syscall(struct pt_regs *regs,
1227                                      enum ptrace_syscall_dir dir)
1228 {
1229         int regno;
1230         unsigned long saved_reg;
1231
1232         /*
1233          * A scratch register (ip(r12) on AArch32, x7 on AArch64) is
1234          * used to denote syscall entry/exit:
1235          */
1236         regno = (is_compat_task() ? 12 : 7);
1237         saved_reg = regs->regs[regno];
1238         regs->regs[regno] = dir;
1239
1240         if (dir == PTRACE_SYSCALL_EXIT)
1241                 tracehook_report_syscall_exit(regs, 0);
1242         else if (tracehook_report_syscall_entry(regs))
1243                 regs->syscallno = ~0UL;
1244
1245         regs->regs[regno] = saved_reg;
1246 }
1247
1248 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
1249 {
1250         /* Do the secure computing check first; failures should be fast. */
1251         if (secure_computing() == -1)
1252                 return -1;
1253
1254         if (test_thread_flag(TIF_SYSCALL_TRACE))
1255                 tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
1256
1257         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1258                 trace_sys_enter(regs, regs->syscallno);
1259
1260         audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
1261                             regs->regs[2], regs->regs[3]);
1262
1263         return regs->syscallno;
1264 }
1265
1266 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
1267 {
1268         audit_syscall_exit(regs);
1269
1270         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1271                 trace_sys_exit(regs, regs_return_value(regs));
1272
1273         if (test_thread_flag(TIF_SYSCALL_TRACE))
1274                 tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
1275 }
1276
1277 /*
1278  * Bits which are always architecturally RES0 per ARM DDI 0487A.h
1279  * Userspace cannot use these until they have an architectural meaning.
1280  * We also reserve IL for the kernel; SS is handled dynamically.
1281  */
1282 #define SPSR_EL1_AARCH64_RES0_BITS \
1283         (GENMASK_ULL(63,32) | GENMASK_ULL(27, 22) | GENMASK_ULL(20, 10) | \
1284          GENMASK_ULL(5, 5))
1285 #define SPSR_EL1_AARCH32_RES0_BITS \
1286         (GENMASK_ULL(63,32) | GENMASK_ULL(24, 22) | GENMASK_ULL(20,20))
1287
1288 static int valid_compat_regs(struct user_pt_regs *regs)
1289 {
1290         regs->pstate &= ~SPSR_EL1_AARCH32_RES0_BITS;
1291
1292         if (!system_supports_mixed_endian_el0()) {
1293                 if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
1294                         regs->pstate |= COMPAT_PSR_E_BIT;
1295                 else
1296                         regs->pstate &= ~COMPAT_PSR_E_BIT;
1297         }
1298
1299         if (user_mode(regs) && (regs->pstate & PSR_MODE32_BIT) &&
1300             (regs->pstate & COMPAT_PSR_A_BIT) == 0 &&
1301             (regs->pstate & COMPAT_PSR_I_BIT) == 0 &&
1302             (regs->pstate & COMPAT_PSR_F_BIT) == 0) {
1303                 return 1;
1304         }
1305
1306         /*
1307          * Force PSR to a valid 32-bit EL0t, preserving the same bits as
1308          * arch/arm.
1309          */
1310         regs->pstate &= COMPAT_PSR_N_BIT | COMPAT_PSR_Z_BIT |
1311                         COMPAT_PSR_C_BIT | COMPAT_PSR_V_BIT |
1312                         COMPAT_PSR_Q_BIT | COMPAT_PSR_IT_MASK |
1313                         COMPAT_PSR_GE_MASK | COMPAT_PSR_E_BIT |
1314                         COMPAT_PSR_T_BIT;
1315         regs->pstate |= PSR_MODE32_BIT;
1316
1317         return 0;
1318 }
1319
1320 static int valid_native_regs(struct user_pt_regs *regs)
1321 {
1322         regs->pstate &= ~SPSR_EL1_AARCH64_RES0_BITS;
1323
1324         if (user_mode(regs) && !(regs->pstate & PSR_MODE32_BIT) &&
1325             (regs->pstate & PSR_D_BIT) == 0 &&
1326             (regs->pstate & PSR_A_BIT) == 0 &&
1327             (regs->pstate & PSR_I_BIT) == 0 &&
1328             (regs->pstate & PSR_F_BIT) == 0) {
1329                 return 1;
1330         }
1331
1332         /* Force PSR to a valid 64-bit EL0t */
1333         regs->pstate &= PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT;
1334
1335         return 0;
1336 }
1337
1338 /*
1339  * Are the current registers suitable for user mode? (used to maintain
1340  * security in signal handlers)
1341  */
1342 int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task)
1343 {
1344         if (!test_tsk_thread_flag(task, TIF_SINGLESTEP))
1345                 regs->pstate &= ~DBG_SPSR_SS;
1346
1347         if (is_compat_thread(task_thread_info(task)))
1348                 return valid_compat_regs(regs);
1349         else
1350                 return valid_native_regs(regs);
1351 }