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/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/mm.h>
  25 #include <linux/smp.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/user.h>
  28 #include <linux/security.h>
  29 #include <linux/init.h>
  30 #include <linux/signal.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/perf_event.h>
  33 #include <linux/hw_breakpoint.h>
  34 #include <linux/regset.h>
  35 #include <linux/tracehook.h>
  36 #include <linux/elf.h>
  37
  38 #include <asm/compat.h>
  39 #include <asm/debug-monitors.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/traps.h>
  42 #include <asm/system_misc.h>
  43
  44 /*
  45  * TODO: does not yet catch signals sent when the child dies.
  46  * in exit.c or in signal.c.
  47  */
  48
  49 /*
  50  * Called by kernel/ptrace.c when detaching..
  51  */
  52 void ptrace_disable(struct task_struct *child)
  53 {
  54 }
  55
  56 #ifdef CONFIG_HAVE_HW_BREAKPOINT
  57 /*
  58  * Handle hitting a HW-breakpoint.
  59  */
  60 static void ptrace_hbptriggered(struct perf_event *bp,
  61                                 struct perf_sample_data *data,
  62                                 struct pt_regs *regs)
  63 {
  64         struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
  65         siginfo_t info = {
  66                 .si_signo       = SIGTRAP,
  67                 .si_errno       = 0,
  68                 .si_code        = TRAP_HWBKPT,
  69                 .si_addr        = (void __user *)(bkpt->trigger),
  70         };
  71
  72 #ifdef CONFIG_COMPAT
  73         int i;
  74
  75         if (!is_compat_task())
  76                 goto send_sig;
  77
  78         for (i = 0; i < ARM_MAX_BRP; ++i) {
  79                 if (current->thread.debug.hbp_break[i] == bp) {
  80                         info.si_errno = (i << 1) + 1;
  81                         break;
  82                 }
  83         }
  84
  85         for (i = 0; i < ARM_MAX_WRP; ++i) {
  86                 if (current->thread.debug.hbp_watch[i] == bp) {
  87                         info.si_errno = -((i << 1) + 1);
  88                         break;
  89                 }
  90         }
  91
  92 send_sig:
  93 #endif
  94         force_sig_info(SIGTRAP, &info, current);
  95 }
  96
  97 /*
  98  * Unregister breakpoints from this task and reset the pointers in
  99  * the thread_struct.
 100  */
 101 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
 102 {
 103         int i;
 104         struct thread_struct *t = &tsk->thread;
 105
 106         for (i = 0; i < ARM_MAX_BRP; i++) {
 107                 if (t->debug.hbp_break[i]) {
 108                         unregister_hw_breakpoint(t->debug.hbp_break[i]);
 109                         t->debug.hbp_break[i] = NULL;
 110                 }
 111         }
 112
 113         for (i = 0; i < ARM_MAX_WRP; i++) {
 114                 if (t->debug.hbp_watch[i]) {
 115                         unregister_hw_breakpoint(t->debug.hbp_watch[i]);
 116                         t->debug.hbp_watch[i] = NULL;
 117                 }
 118         }
 119 }
 120
 121 void ptrace_hw_copy_thread(struct task_struct *tsk)
 122 {
 123         memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
 124 }
 125
 126 static struct perf_event *ptrace_hbp_get_event(unsigned int note_type,
 127                                                struct task_struct *tsk,
 128                                                unsigned long idx)
 129 {
 130         struct perf_event *bp = ERR_PTR(-EINVAL);
 131
 132         switch (note_type) {
 133         case NT_ARM_HW_BREAK:
 134                 if (idx < ARM_MAX_BRP)
 135                         bp = tsk->thread.debug.hbp_break[idx];
 136                 break;
 137         case NT_ARM_HW_WATCH:
 138                 if (idx < ARM_MAX_WRP)
 139                         bp = tsk->thread.debug.hbp_watch[idx];
 140                 break;
 141         }
 142
 143         return bp;
 144 }
 145
 146 static int ptrace_hbp_set_event(unsigned int note_type,
 147                                 struct task_struct *tsk,
 148                                 unsigned long idx,
 149                                 struct perf_event *bp)
 150 {
 151         int err = -EINVAL;
 152
 153         switch (note_type) {
 154         case NT_ARM_HW_BREAK:
 155                 if (idx < ARM_MAX_BRP) {
 156                         tsk->thread.debug.hbp_break[idx] = bp;
 157                         err = 0;
 158                 }
 159                 break;
 160         case NT_ARM_HW_WATCH:
 161                 if (idx < ARM_MAX_WRP) {
 162                         tsk->thread.debug.hbp_watch[idx] = bp;
 163                         err = 0;
 164                 }
 165                 break;
 166         }
 167
 168         return err;
 169 }
 170
 171 static struct perf_event *ptrace_hbp_create(unsigned int note_type,
 172                                             struct task_struct *tsk,
 173                                             unsigned long idx)
 174 {
 175         struct perf_event *bp;
 176         struct perf_event_attr attr;
 177         int err, type;
 178
 179         switch (note_type) {
 180         case NT_ARM_HW_BREAK:
 181                 type = HW_BREAKPOINT_X;
 182                 break;
 183         case NT_ARM_HW_WATCH:
 184                 type = HW_BREAKPOINT_RW;
 185                 break;
 186         default:
 187                 return ERR_PTR(-EINVAL);
 188         }
 189
 190         ptrace_breakpoint_init(&attr);
 191
 192         /*
 193          * Initialise fields to sane defaults
 194          * (i.e. values that will pass validation).
 195          */
 196         attr.bp_addr    = 0;
 197         attr.bp_len     = HW_BREAKPOINT_LEN_4;
 198         attr.bp_type    = type;
 199         attr.disabled   = 1;
 200
 201         bp = register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, tsk);
 202         if (IS_ERR(bp))
 203                 return bp;
 204
 205         err = ptrace_hbp_set_event(note_type, tsk, idx, bp);
 206         if (err)
 207                 return ERR_PTR(err);
 208
 209         return bp;
 210 }
 211
 212 static int ptrace_hbp_fill_attr_ctrl(unsigned int note_type,
 213                                      struct arch_hw_breakpoint_ctrl ctrl,
 214                                      struct perf_event_attr *attr)
 215 {
 216         int err, len, type, disabled = !ctrl.enabled;
 217
 218         attr->disabled = disabled;
 219         if (disabled)
 220                 return 0;
 221
 222         err = arch_bp_generic_fields(ctrl, &len, &type);
 223         if (err)
 224                 return err;
 225
 226         switch (note_type) {
 227         case NT_ARM_HW_BREAK:
 228                 if ((type & HW_BREAKPOINT_X) != type)
 229                         return -EINVAL;
 230                 break;
 231         case NT_ARM_HW_WATCH:
 232                 if ((type & HW_BREAKPOINT_RW) != type)
 233                         return -EINVAL;
 234                 break;
 235         default:
 236                 return -EINVAL;
 237         }
 238
 239         attr->bp_len    = len;
 240         attr->bp_type   = type;
 241
 242         return 0;
 243 }
 244
 245 static int ptrace_hbp_get_resource_info(unsigned int note_type, u32 *info)
 246 {
 247         u8 num;
 248         u32 reg = 0;
 249
 250         switch (note_type) {
 251         case NT_ARM_HW_BREAK:
 252                 num = hw_breakpoint_slots(TYPE_INST);
 253                 break;
 254         case NT_ARM_HW_WATCH:
 255                 num = hw_breakpoint_slots(TYPE_DATA);
 256                 break;
 257         default:
 258                 return -EINVAL;
 259         }
 260
 261         reg |= debug_monitors_arch();
 262         reg <<= 8;
 263         reg |= num;
 264
 265         *info = reg;
 266         return 0;
 267 }
 268
 269 static int ptrace_hbp_get_ctrl(unsigned int note_type,
 270                                struct task_struct *tsk,
 271                                unsigned long idx,
 272                                u32 *ctrl)
 273 {
 274         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 275
 276         if (IS_ERR(bp))
 277                 return PTR_ERR(bp);
 278
 279         *ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
 280         return 0;
 281 }
 282
 283 static int ptrace_hbp_get_addr(unsigned int note_type,
 284                                struct task_struct *tsk,
 285                                unsigned long idx,
 286                                u64 *addr)
 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         *addr = bp ? bp->attr.bp_addr : 0;
 294         return 0;
 295 }
 296
 297 static struct perf_event *ptrace_hbp_get_initialised_bp(unsigned int note_type,
 298                                                         struct task_struct *tsk,
 299                                                         unsigned long idx)
 300 {
 301         struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
 302
 303         if (!bp)
 304                 bp = ptrace_hbp_create(note_type, tsk, idx);
 305
 306         return bp;
 307 }
 308
 309 static int ptrace_hbp_set_ctrl(unsigned int note_type,
 310                                struct task_struct *tsk,
 311                                unsigned long idx,
 312                                u32 uctrl)
 313 {
 314         int err;
 315         struct perf_event *bp;
 316         struct perf_event_attr attr;
 317         struct arch_hw_breakpoint_ctrl ctrl;
 318
 319         bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
 320         if (IS_ERR(bp)) {
 321                 err = PTR_ERR(bp);
 322                 return err;
 323         }
 324
 325         attr = bp->attr;
 326         decode_ctrl_reg(uctrl, &ctrl);
 327         err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr);
 328         if (err)
 329                 return err;
 330
 331         return modify_user_hw_breakpoint(bp, &attr);
 332 }
 333
 334 static int ptrace_hbp_set_addr(unsigned int note_type,
 335                                struct task_struct *tsk,
 336                                unsigned long idx,
 337                                u64 addr)
 338 {
 339         int err;
 340         struct perf_event *bp;
 341         struct perf_event_attr attr;
 342
 343         bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
 344         if (IS_ERR(bp)) {
 345                 err = PTR_ERR(bp);
 346                 return err;
 347         }
 348
 349         attr = bp->attr;
 350         attr.bp_addr = addr;
 351         err = modify_user_hw_breakpoint(bp, &attr);
 352         return err;
 353 }
 354
 355 #define PTRACE_HBP_ADDR_SZ      sizeof(u64)
 356 #define PTRACE_HBP_CTRL_SZ      sizeof(u32)
 357 #define PTRACE_HBP_PAD_SZ       sizeof(u32)
 358
 359 static int hw_break_get(struct task_struct *target,
 360                         const struct user_regset *regset,
 361                         unsigned int pos, unsigned int count,
 362                         void *kbuf, void __user *ubuf)
 363 {
 364         unsigned int note_type = regset->core_note_type;
 365         int ret, idx = 0, offset, limit;
 366         u32 info, ctrl;
 367         u64 addr;
 368
 369         /* Resource info */
 370         ret = ptrace_hbp_get_resource_info(note_type, &info);
 371         if (ret)
 372                 return ret;
 373
 374         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &info, 0,
 375                                   sizeof(info));
 376         if (ret)
 377                 return ret;
 378
 379         /* Pad */
 380         offset = offsetof(struct user_hwdebug_state, pad);
 381         ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, offset,
 382                                        offset + PTRACE_HBP_PAD_SZ);
 383         if (ret)
 384                 return ret;
 385
 386         /* (address, ctrl) registers */
 387         offset = offsetof(struct user_hwdebug_state, dbg_regs);
 388         limit = regset->n * regset->size;
 389         while (count && offset < limit) {
 390                 ret = ptrace_hbp_get_addr(note_type, target, idx, &addr);
 391                 if (ret)
 392                         return ret;
 393                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &addr,
 394                                           offset, offset + PTRACE_HBP_ADDR_SZ);
 395                 if (ret)
 396                         return ret;
 397                 offset += PTRACE_HBP_ADDR_SZ;
 398
 399                 ret = ptrace_hbp_get_ctrl(note_type, target, idx, &ctrl);
 400                 if (ret)
 401                         return ret;
 402                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &ctrl,
 403                                           offset, offset + PTRACE_HBP_CTRL_SZ);
 404                 if (ret)
 405                         return ret;
 406                 offset += PTRACE_HBP_CTRL_SZ;
 407
 408                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 409                                                offset,
 410                                                offset + PTRACE_HBP_PAD_SZ);
 411                 if (ret)
 412                         return ret;
 413                 offset += PTRACE_HBP_PAD_SZ;
 414                 idx++;
 415         }
 416
 417         return 0;
 418 }
 419
 420 static int hw_break_set(struct task_struct *target,
 421                         const struct user_regset *regset,
 422                         unsigned int pos, unsigned int count,
 423                         const void *kbuf, const void __user *ubuf)
 424 {
 425         unsigned int note_type = regset->core_note_type;
 426         int ret, idx = 0, offset, limit;
 427         u32 ctrl;
 428         u64 addr;
 429
 430         /* Resource info and pad */
 431         offset = offsetof(struct user_hwdebug_state, dbg_regs);
 432         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, offset);
 433         if (ret)
 434                 return ret;
 435
 436         /* (address, ctrl) registers */
 437         limit = regset->n * regset->size;
 438         while (count && offset < limit) {
 439                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
 440                                          offset, offset + PTRACE_HBP_ADDR_SZ);
 441                 if (ret)
 442                         return ret;
 443                 ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
 444                 if (ret)
 445                         return ret;
 446                 offset += PTRACE_HBP_ADDR_SZ;
 447
 448                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
 449                                          offset, offset + PTRACE_HBP_CTRL_SZ);
 450                 if (ret)
 451                         return ret;
 452                 ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
 453                 if (ret)
 454                         return ret;
 455                 offset += PTRACE_HBP_CTRL_SZ;
 456
 457                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 458                                                 offset,
 459                                                 offset + PTRACE_HBP_PAD_SZ);
 460                 if (ret)
 461                         return ret;
 462                 offset += PTRACE_HBP_PAD_SZ;
 463                 idx++;
 464         }
 465
 466         return 0;
 467 }
 468 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
 469
 470 static int gpr_get(struct task_struct *target,
 471                    const struct user_regset *regset,
 472                    unsigned int pos, unsigned int count,
 473                    void *kbuf, void __user *ubuf)
 474 {
 475         struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
 476         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 477 }
 478
 479 static int gpr_set(struct task_struct *target, const struct user_regset *regset,
 480                    unsigned int pos, unsigned int count,
 481                    const void *kbuf, const void __user *ubuf)
 482 {
 483         int ret;
 484         struct user_pt_regs newregs;
 485
 486         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
 487         if (ret)
 488                 return ret;
 489
 490         if (!valid_user_regs(&newregs))
 491                 return -EINVAL;
 492
 493         task_pt_regs(target)->user_regs = newregs;
 494         return 0;
 495 }
 496
 497 /*
 498  * TODO: update fp accessors for lazy context switching (sync/flush hwstate)
 499  */
 500 static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 501                    unsigned int pos, unsigned int count,
 502                    void *kbuf, void __user *ubuf)
 503 {
 504         struct user_fpsimd_state *uregs;
 505         uregs = &target->thread.fpsimd_state.user_fpsimd;
 506         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
 507 }
 508
 509 static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 510                    unsigned int pos, unsigned int count,
 511                    const void *kbuf, const void __user *ubuf)
 512 {
 513         int ret;
 514         struct user_fpsimd_state newstate;
 515
 516         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 517         if (ret)
 518                 return ret;
 519
 520         target->thread.fpsimd_state.user_fpsimd = newstate;
 521         return ret;
 522 }
 523
 524 static int tls_get(struct task_struct *target, const struct user_regset *regset,
 525                    unsigned int pos, unsigned int count,
 526                    void *kbuf, void __user *ubuf)
 527 {
 528         unsigned long *tls = &target->thread.tp_value;
 529         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, tls, 0, -1);
 530 }
 531
 532 static int tls_set(struct task_struct *target, const struct user_regset *regset,
 533                    unsigned int pos, unsigned int count,
 534                    const void *kbuf, const void __user *ubuf)
 535 {
 536         int ret;
 537         unsigned long tls;
 538
 539         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 540         if (ret)
 541                 return ret;
 542
 543         target->thread.tp_value = tls;
 544         return ret;
 545 }
 546
 547 enum aarch64_regset {
 548         REGSET_GPR,
 549         REGSET_FPR,
 550         REGSET_TLS,
 551 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 552         REGSET_HW_BREAK,
 553         REGSET_HW_WATCH,
 554 #endif
 555 };
 556
 557 static const struct user_regset aarch64_regsets[] = {
 558         [REGSET_GPR] = {
 559                 .core_note_type = NT_PRSTATUS,
 560                 .n = sizeof(struct user_pt_regs) / sizeof(u64),
 561                 .size = sizeof(u64),
 562                 .align = sizeof(u64),
 563                 .get = gpr_get,
 564                 .set = gpr_set
 565         },
 566         [REGSET_FPR] = {
 567                 .core_note_type = NT_PRFPREG,
 568                 .n = sizeof(struct user_fpsimd_state) / sizeof(u32),
 569                 /*
 570                  * We pretend we have 32-bit registers because the fpsr and
 571                  * fpcr are 32-bits wide.
 572                  */
 573                 .size = sizeof(u32),
 574                 .align = sizeof(u32),
 575                 .get = fpr_get,
 576                 .set = fpr_set
 577         },
 578         [REGSET_TLS] = {
 579                 .core_note_type = NT_ARM_TLS,
 580                 .n = 1,
 581                 .size = sizeof(void *),
 582                 .align = sizeof(void *),
 583                 .get = tls_get,
 584                 .set = tls_set,
 585         },
 586 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 587         [REGSET_HW_BREAK] = {
 588                 .core_note_type = NT_ARM_HW_BREAK,
 589                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 590                 .size = sizeof(u32),
 591                 .align = sizeof(u32),
 592                 .get = hw_break_get,
 593                 .set = hw_break_set,
 594         },
 595         [REGSET_HW_WATCH] = {
 596                 .core_note_type = NT_ARM_HW_WATCH,
 597                 .n = sizeof(struct user_hwdebug_state) / sizeof(u32),
 598                 .size = sizeof(u32),
 599                 .align = sizeof(u32),
 600                 .get = hw_break_get,
 601                 .set = hw_break_set,
 602         },
 603 #endif
 604 };
 605
 606 static const struct user_regset_view user_aarch64_view = {
 607         .name = "aarch64", .e_machine = EM_AARCH64,
 608         .regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
 609 };
 610
 611 #ifdef CONFIG_COMPAT
 612 #include <linux/compat.h>
 613
 614 enum compat_regset {
 615         REGSET_COMPAT_GPR,
 616         REGSET_COMPAT_VFP,
 617 };
 618
 619 static int compat_gpr_get(struct task_struct *target,
 620                           const struct user_regset *regset,
 621                           unsigned int pos, unsigned int count,
 622                           void *kbuf, void __user *ubuf)
 623 {
 624         int ret = 0;
 625         unsigned int i, start, num_regs;
 626
 627         /* Calculate the number of AArch32 registers contained in count */
 628         num_regs = count / regset->size;
 629
 630         /* Convert pos into an register number */
 631         start = pos / regset->size;
 632
 633         if (start + num_regs > regset->n)
 634                 return -EIO;
 635
 636         for (i = 0; i < num_regs; ++i) {
 637                 unsigned int idx = start + i;
 638                 void *reg;
 639
 640                 switch (idx) {
 641                 case 15:
 642                         reg = (void *)&task_pt_regs(target)->pc;
 643                         break;
 644                 case 16:
 645                         reg = (void *)&task_pt_regs(target)->pstate;
 646                         break;
 647                 case 17:
 648                         reg = (void *)&task_pt_regs(target)->orig_x0;
 649                         break;
 650                 default:
 651                         reg = (void *)&task_pt_regs(target)->regs[idx];
 652                 }
 653
 654                 if (kbuf) {
 655                         memcpy(kbuf, &reg, sizeof(reg));
 656                         kbuf += sizeof(reg);
 657                 } else {
 658                         ret = copy_to_user(ubuf, &reg, sizeof(reg));
 659                         if (ret) {
 660                                 ret = -EFAULT;
 661                                 break;
 662                         }
 663
 664                         ubuf += sizeof(reg);
 665                 }
 666         }
 667
 668         return ret;
 669 }
 670
 671 static int compat_gpr_set(struct task_struct *target,
 672                           const struct user_regset *regset,
 673                           unsigned int pos, unsigned int count,
 674                           const void *kbuf, const void __user *ubuf)
 675 {
 676         struct pt_regs newregs;
 677         int ret = 0;
 678         unsigned int i, start, num_regs;
 679
 680         /* Calculate the number of AArch32 registers contained in count */
 681         num_regs = count / regset->size;
 682
 683         /* Convert pos into an register number */
 684         start = pos / regset->size;
 685
 686         if (start + num_regs > regset->n)
 687                 return -EIO;
 688
 689         newregs = *task_pt_regs(target);
 690
 691         for (i = 0; i < num_regs; ++i) {
 692                 unsigned int idx = start + i;
 693                 compat_ulong_t reg;
 694
 695                 if (kbuf) {
 696                         memcpy(&reg, kbuf, sizeof(reg));
 697                         kbuf += sizeof(reg);
 698                 } else {
 699                         ret = copy_from_user(&reg, ubuf, sizeof(reg));
 700                         if (ret) {
 701                                 ret = -EFAULT;
 702                                 break;
 703                         }
 704
 705                         ubuf += sizeof(reg);
 706                 }
 707
 708                 switch (idx) {
 709                 case 15:
 710                         reg = (void *)&newregs.pc;
 711                         break;
 712                 case 16:
 713                         reg = (void *)&newregs.pstate;
 714                         break;
 715                 case 17:
 716                         reg = (void *)&newregs.orig_x0;
 717                         break;
 718                 default:
 719                         reg = (void *)&newregs.regs[idx];
 720                 }
 721
 722                 ret = copy_from_user(reg, ubuf, sizeof(compat_ulong_t));
 723
 724                 if (ret)
 725                         goto out;
 726                 else
 727                         ubuf += sizeof(compat_ulong_t);
 728         }
 729
 730         if (valid_user_regs(&newregs.user_regs))
 731                 *task_pt_regs(target) = newregs;
 732         else
 733                 ret = -EINVAL;
 734
 735 out:
 736         return ret;
 737 }
 738
 739 static int compat_vfp_get(struct task_struct *target,
 740                           const struct user_regset *regset,
 741                           unsigned int pos, unsigned int count,
 742                           void *kbuf, void __user *ubuf)
 743 {
 744         struct user_fpsimd_state *uregs;
 745         compat_ulong_t fpscr;
 746         int ret;
 747
 748         uregs = &target->thread.fpsimd_state.user_fpsimd;
 749
 750         /*
 751          * The VFP registers are packed into the fpsimd_state, so they all sit
 752          * nicely together for us. We just need to create the fpscr separately.
 753          */
 754         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0,
 755                                   VFP_STATE_SIZE - sizeof(compat_ulong_t));
 756
 757         if (count && !ret) {
 758                 fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
 759                         (uregs->fpcr & VFP_FPSCR_CTRL_MASK);
 760                 ret = put_user(fpscr, (compat_ulong_t *)ubuf);
 761         }
 762
 763         return ret;
 764 }
 765
 766 static int compat_vfp_set(struct task_struct *target,
 767                           const struct user_regset *regset,
 768                           unsigned int pos, unsigned int count,
 769                           const void *kbuf, const void __user *ubuf)
 770 {
 771         struct user_fpsimd_state *uregs;
 772         compat_ulong_t fpscr;
 773         int ret;
 774
 775         if (pos + count > VFP_STATE_SIZE)
 776                 return -EIO;
 777
 778         uregs = &target->thread.fpsimd_state.user_fpsimd;
 779
 780         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
 781                                  VFP_STATE_SIZE - sizeof(compat_ulong_t));
 782
 783         if (count && !ret) {
 784                 ret = get_user(fpscr, (compat_ulong_t *)ubuf);
 785                 uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
 786                 uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 787         }
 788
 789         return ret;
 790 }
 791
 792 static const struct user_regset aarch32_regsets[] = {
 793         [REGSET_COMPAT_GPR] = {
 794                 .core_note_type = NT_PRSTATUS,
 795                 .n = COMPAT_ELF_NGREG,
 796                 .size = sizeof(compat_elf_greg_t),
 797                 .align = sizeof(compat_elf_greg_t),
 798                 .get = compat_gpr_get,
 799                 .set = compat_gpr_set
 800         },
 801         [REGSET_COMPAT_VFP] = {
 802                 .core_note_type = NT_ARM_VFP,
 803                 .n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
 804                 .size = sizeof(compat_ulong_t),
 805                 .align = sizeof(compat_ulong_t),
 806                 .get = compat_vfp_get,
 807                 .set = compat_vfp_set
 808         },
 809 };
 810
 811 static const struct user_regset_view user_aarch32_view = {
 812         .name = "aarch32", .e_machine = EM_ARM,
 813         .regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
 814 };
 815
 816 static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
 817                                    compat_ulong_t __user *ret)
 818 {
 819         compat_ulong_t tmp;
 820
 821         if (off & 3)
 822                 return -EIO;
 823
 824         if (off == COMPAT_PT_TEXT_ADDR)
 825                 tmp = tsk->mm->start_code;
 826         else if (off == COMPAT_PT_DATA_ADDR)
 827                 tmp = tsk->mm->start_data;
 828         else if (off == COMPAT_PT_TEXT_END_ADDR)
 829                 tmp = tsk->mm->end_code;
 830         else if (off < sizeof(compat_elf_gregset_t))
 831                 return copy_regset_to_user(tsk, &user_aarch32_view,
 832                                            REGSET_COMPAT_GPR, off,
 833                                            sizeof(compat_ulong_t), ret);
 834         else if (off >= COMPAT_USER_SZ)
 835                 return -EIO;
 836         else
 837                 tmp = 0;
 838
 839         return put_user(tmp, ret);
 840 }
 841
 842 static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
 843                                     compat_ulong_t val)
 844 {
 845         int ret;
 846         mm_segment_t old_fs = get_fs();
 847
 848         if (off & 3 || off >= COMPAT_USER_SZ)
 849                 return -EIO;
 850
 851         if (off >= sizeof(compat_elf_gregset_t))
 852                 return 0;
 853
 854         set_fs(KERNEL_DS);
 855         ret = copy_regset_from_user(tsk, &user_aarch32_view,
 856                                     REGSET_COMPAT_GPR, off,
 857                                     sizeof(compat_ulong_t),
 858                                     &val);
 859         set_fs(old_fs);
 860
 861         return ret;
 862 }
 863
 864 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 865
 866 /*
 867  * Convert a virtual register number into an index for a thread_info
 868  * breakpoint array. Breakpoints are identified using positive numbers
 869  * whilst watchpoints are negative. The registers are laid out as pairs
 870  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
 871  * Register 0 is reserved for describing resource information.
 872  */
 873 static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
 874 {
 875         return (abs(num) - 1) >> 1;
 876 }
 877
 878 static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
 879 {
 880         u8 num_brps, num_wrps, debug_arch, wp_len;
 881         u32 reg = 0;
 882
 883         num_brps        = hw_breakpoint_slots(TYPE_INST);
 884         num_wrps        = hw_breakpoint_slots(TYPE_DATA);
 885
 886         debug_arch      = debug_monitors_arch();
 887         wp_len          = 8;
 888         reg             |= debug_arch;
 889         reg             <<= 8;
 890         reg             |= wp_len;
 891         reg             <<= 8;
 892         reg             |= num_wrps;
 893         reg             <<= 8;
 894         reg             |= num_brps;
 895
 896         *kdata = reg;
 897         return 0;
 898 }
 899
 900 static int compat_ptrace_hbp_get(unsigned int note_type,
 901                                  struct task_struct *tsk,
 902                                  compat_long_t num,
 903                                  u32 *kdata)
 904 {
 905         u64 addr = 0;
 906         u32 ctrl = 0;
 907
 908         int err, idx = compat_ptrace_hbp_num_to_idx(num);;
 909
 910         if (num & 1) {
 911                 err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
 912                 *kdata = (u32)addr;
 913         } else {
 914                 err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
 915                 *kdata = ctrl;
 916         }
 917
 918         return err;
 919 }
 920
 921 static int compat_ptrace_hbp_set(unsigned int note_type,
 922                                  struct task_struct *tsk,
 923                                  compat_long_t num,
 924                                  u32 *kdata)
 925 {
 926         u64 addr;
 927         u32 ctrl;
 928
 929         int err, idx = compat_ptrace_hbp_num_to_idx(num);
 930
 931         if (num & 1) {
 932                 addr = *kdata;
 933                 err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
 934         } else {
 935                 ctrl = *kdata;
 936                 err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
 937         }
 938
 939         return err;
 940 }
 941
 942 static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
 943                                     compat_ulong_t __user *data)
 944 {
 945         int ret;
 946         u32 kdata;
 947         mm_segment_t old_fs = get_fs();
 948
 949         set_fs(KERNEL_DS);
 950         /* Watchpoint */
 951         if (num < 0) {
 952                 ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
 953         /* Resource info */
 954         } else if (num == 0) {
 955                 ret = compat_ptrace_hbp_get_resource_info(&kdata);
 956         /* Breakpoint */
 957         } else {
 958                 ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
 959         }
 960         set_fs(old_fs);
 961
 962         if (!ret)
 963                 ret = put_user(kdata, data);
 964
 965         return ret;
 966 }
 967
 968 static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
 969                                     compat_ulong_t __user *data)
 970 {
 971         int ret;
 972         u32 kdata = 0;
 973         mm_segment_t old_fs = get_fs();
 974
 975         if (num == 0)
 976                 return 0;
 977
 978         ret = get_user(kdata, data);
 979         if (ret)
 980                 return ret;
 981
 982         set_fs(KERNEL_DS);
 983         if (num < 0)
 984                 ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
 985         else
 986                 ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
 987         set_fs(old_fs);
 988
 989         return ret;
 990 }
 991 #endif  /* CONFIG_HAVE_HW_BREAKPOINT */
 992
 993 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 994                         compat_ulong_t caddr, compat_ulong_t cdata)
 995 {
 996         unsigned long addr = caddr;
 997         unsigned long data = cdata;
 998         void __user *datap = compat_ptr(data);
 999         int ret;
1000
1001         switch (request) {
1002                 case PTRACE_PEEKUSR:
1003                         ret = compat_ptrace_read_user(child, addr, datap);
1004                         break;
1005
1006                 case PTRACE_POKEUSR:
1007                         ret = compat_ptrace_write_user(child, addr, data);
1008                         break;
1009
1010                 case COMPAT_PTRACE_GETREGS:
1011                         ret = copy_regset_to_user(child,
1012                                                   &user_aarch32_view,
1013                                                   REGSET_COMPAT_GPR,
1014                                                   0, sizeof(compat_elf_gregset_t),
1015                                                   datap);
1016                         break;
1017
1018                 case COMPAT_PTRACE_SETREGS:
1019                         ret = copy_regset_from_user(child,
1020                                                     &user_aarch32_view,
1021                                                     REGSET_COMPAT_GPR,
1022                                                     0, sizeof(compat_elf_gregset_t),
1023                                                     datap);
1024                         break;
1025
1026                 case COMPAT_PTRACE_GET_THREAD_AREA:
1027                         ret = put_user((compat_ulong_t)child->thread.tp_value,
1028                                        (compat_ulong_t __user *)datap);
1029                         break;
1030
1031                 case COMPAT_PTRACE_SET_SYSCALL:
1032                         task_pt_regs(child)->syscallno = data;
1033                         ret = 0;
1034                         break;
1035
1036                 case COMPAT_PTRACE_GETVFPREGS:
1037                         ret = copy_regset_to_user(child,
1038                                                   &user_aarch32_view,
1039                                                   REGSET_COMPAT_VFP,
1040                                                   0, VFP_STATE_SIZE,
1041                                                   datap);
1042                         break;
1043
1044                 case COMPAT_PTRACE_SETVFPREGS:
1045                         ret = copy_regset_from_user(child,
1046                                                     &user_aarch32_view,
1047                                                     REGSET_COMPAT_VFP,
1048                                                     0, VFP_STATE_SIZE,
1049                                                     datap);
1050                         break;
1051
1052 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1053                 case COMPAT_PTRACE_GETHBPREGS:
1054                         ret = compat_ptrace_gethbpregs(child, addr, datap);
1055                         break;
1056
1057                 case COMPAT_PTRACE_SETHBPREGS:
1058                         ret = compat_ptrace_sethbpregs(child, addr, datap);
1059                         break;
1060 #endif
1061
1062                 default:
1063                         ret = compat_ptrace_request(child, request, addr,
1064                                                     data);
1065                         break;
1066         }
1067
1068         return ret;
1069 }
1070 #endif /* CONFIG_COMPAT */
1071
1072 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1073 {
1074 #ifdef CONFIG_COMPAT
1075         if (is_compat_thread(task_thread_info(task)))
1076                 return &user_aarch32_view;
1077 #endif
1078         return &user_aarch64_view;
1079 }
1080
1081 long arch_ptrace(struct task_struct *child, long request,
1082                  unsigned long addr, unsigned long data)
1083 {
1084         return ptrace_request(child, request, addr, data);
1085 }
1086
1087 asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
1088 {
1089         unsigned long saved_reg;
1090
1091         if (!test_thread_flag(TIF_SYSCALL_TRACE))
1092                 return regs->syscallno;
1093
1094         if (is_compat_task()) {
1095                 /* AArch32 uses ip (r12) for scratch */
1096                 saved_reg = regs->regs[12];
1097                 regs->regs[12] = dir;
1098         } else {
1099                 /*
1100                  * Save X7. X7 is used to denote syscall entry/exit:
1101                  *   X7 = 0 -> entry, = 1 -> exit
1102                  */
1103                 saved_reg = regs->regs[7];
1104                 regs->regs[7] = dir;
1105         }
1106
1107         if (dir)
1108                 tracehook_report_syscall_exit(regs, 0);
1109         else if (tracehook_report_syscall_entry(regs))
1110                 regs->syscallno = ~0UL;
1111
1112         if (is_compat_task())
1113                 regs->regs[12] = saved_reg;
1114         else
1115                 regs->regs[7] = saved_reg;
1116
1117         return regs->syscallno;
1118 }