arch/x86/kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* By Ross Biro 1/23/92 */
   3 /*
   4  * Pentium III FXSR, SSE support
   5  *      Gareth Hughes <[email protected]>, May 2000
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/sched/task_stack.h>
  11 #include <linux/mm.h>
  12 #include <linux/smp.h>
  13 #include <linux/errno.h>
  14 #include <linux/slab.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/user.h>
  17 #include <linux/elf.h>
  18 #include <linux/security.h>
  19 #include <linux/audit.h>
  20 #include <linux/seccomp.h>
  21 #include <linux/signal.h>
  22 #include <linux/perf_event.h>
  23 #include <linux/hw_breakpoint.h>
  24 #include <linux/rcupdate.h>
  25 #include <linux/export.h>
  26 #include <linux/context_tracking.h>
  27 #include <linux/nospec.h>
  28
  29 #include <linux/uaccess.h>
  30 #include <asm/processor.h>
  31 #include <asm/fpu/signal.h>
  32 #include <asm/fpu/regset.h>
  33 #include <asm/fpu/xstate.h>
  34 #include <asm/debugreg.h>
  35 #include <asm/ldt.h>
  36 #include <asm/desc.h>
  37 #include <asm/prctl.h>
  38 #include <asm/proto.h>
  39 #include <asm/hw_breakpoint.h>
  40 #include <asm/traps.h>
  41 #include <asm/syscall.h>
  42 #include <asm/fsgsbase.h>
  43 #include <asm/io_bitmap.h>
  44
  45 #include "tls.h"
  46
  47 enum x86_regset_32 {
  48         REGSET32_GENERAL,
  49         REGSET32_FP,
  50         REGSET32_XFP,
  51         REGSET32_XSTATE,
  52         REGSET32_TLS,
  53         REGSET32_IOPERM,
  54 };
  55
  56 enum x86_regset_64 {
  57         REGSET64_GENERAL,
  58         REGSET64_FP,
  59         REGSET64_IOPERM,
  60         REGSET64_XSTATE,
  61 };
  62
  63 #define REGSET_GENERAL \
  64 ({ \
  65         BUILD_BUG_ON((int)REGSET32_GENERAL != (int)REGSET64_GENERAL); \
  66         REGSET32_GENERAL; \
  67 })
  68
  69 #define REGSET_FP \
  70 ({ \
  71         BUILD_BUG_ON((int)REGSET32_FP != (int)REGSET64_FP); \
  72         REGSET32_FP; \
  73 })
  74
  75
  76 struct pt_regs_offset {
  77         const char *name;
  78         int offset;
  79 };
  80
  81 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
  82 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  83
  84 static const struct pt_regs_offset regoffset_table[] = {
  85 #ifdef CONFIG_X86_64
  86         REG_OFFSET_NAME(r15),
  87         REG_OFFSET_NAME(r14),
  88         REG_OFFSET_NAME(r13),
  89         REG_OFFSET_NAME(r12),
  90         REG_OFFSET_NAME(r11),
  91         REG_OFFSET_NAME(r10),
  92         REG_OFFSET_NAME(r9),
  93         REG_OFFSET_NAME(r8),
  94 #endif
  95         REG_OFFSET_NAME(bx),
  96         REG_OFFSET_NAME(cx),
  97         REG_OFFSET_NAME(dx),
  98         REG_OFFSET_NAME(si),
  99         REG_OFFSET_NAME(di),
 100         REG_OFFSET_NAME(bp),
 101         REG_OFFSET_NAME(ax),
 102 #ifdef CONFIG_X86_32
 103         REG_OFFSET_NAME(ds),
 104         REG_OFFSET_NAME(es),
 105         REG_OFFSET_NAME(fs),
 106         REG_OFFSET_NAME(gs),
 107 #endif
 108         REG_OFFSET_NAME(orig_ax),
 109         REG_OFFSET_NAME(ip),
 110         REG_OFFSET_NAME(cs),
 111         REG_OFFSET_NAME(flags),
 112         REG_OFFSET_NAME(sp),
 113         REG_OFFSET_NAME(ss),
 114         REG_OFFSET_END,
 115 };
 116
 117 /**
 118  * regs_query_register_offset() - query register offset from its name
 119  * @name:       the name of a register
 120  *
 121  * regs_query_register_offset() returns the offset of a register in struct
 122  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 123  */
 124 int regs_query_register_offset(const char *name)
 125 {
 126         const struct pt_regs_offset *roff;
 127         for (roff = regoffset_table; roff->name != NULL; roff++)
 128                 if (!strcmp(roff->name, name))
 129                         return roff->offset;
 130         return -EINVAL;
 131 }
 132
 133 /**
 134  * regs_query_register_name() - query register name from its offset
 135  * @offset:     the offset of a register in struct pt_regs.
 136  *
 137  * regs_query_register_name() returns the name of a register from its
 138  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 139  */
 140 const char *regs_query_register_name(unsigned int offset)
 141 {
 142         const struct pt_regs_offset *roff;
 143         for (roff = regoffset_table; roff->name != NULL; roff++)
 144                 if (roff->offset == offset)
 145                         return roff->name;
 146         return NULL;
 147 }
 148
 149 /*
 150  * does not yet catch signals sent when the child dies.
 151  * in exit.c or in signal.c.
 152  */
 153
 154 /*
 155  * Determines which flags the user has access to [1 = access, 0 = no access].
 156  */
 157 #define FLAG_MASK_32            ((unsigned long)                        \
 158                                  (X86_EFLAGS_CF | X86_EFLAGS_PF |       \
 159                                   X86_EFLAGS_AF | X86_EFLAGS_ZF |       \
 160                                   X86_EFLAGS_SF | X86_EFLAGS_TF |       \
 161                                   X86_EFLAGS_DF | X86_EFLAGS_OF |       \
 162                                   X86_EFLAGS_RF | X86_EFLAGS_AC))
 163
 164 /*
 165  * Determines whether a value may be installed in a segment register.
 166  */
 167 static inline bool invalid_selector(u16 value)
 168 {
 169         return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
 170 }
 171
 172 #ifdef CONFIG_X86_32
 173
 174 #define FLAG_MASK               FLAG_MASK_32
 175
 176 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
 177 {
 178         BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
 179         return &regs->bx + (regno >> 2);
 180 }
 181
 182 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
 183 {
 184         /*
 185          * Returning the value truncates it to 16 bits.
 186          */
 187         unsigned int retval;
 188         if (offset != offsetof(struct user_regs_struct, gs))
 189                 retval = *pt_regs_access(task_pt_regs(task), offset);
 190         else {
 191                 if (task == current)
 192                         savesegment(gs, retval);
 193                 else
 194                         retval = task->thread.gs;
 195         }
 196         return retval;
 197 }
 198
 199 static int set_segment_reg(struct task_struct *task,
 200                            unsigned long offset, u16 value)
 201 {
 202         if (WARN_ON_ONCE(task == current))
 203                 return -EIO;
 204
 205         /*
 206          * The value argument was already truncated to 16 bits.
 207          */
 208         if (invalid_selector(value))
 209                 return -EIO;
 210
 211         /*
 212          * For %cs and %ss we cannot permit a null selector.
 213          * We can permit a bogus selector as long as it has USER_RPL.
 214          * Null selectors are fine for other segment registers, but
 215          * we will never get back to user mode with invalid %cs or %ss
 216          * and will take the trap in iret instead.  Much code relies
 217          * on user_mode() to distinguish a user trap frame (which can
 218          * safely use invalid selectors) from a kernel trap frame.
 219          */
 220         switch (offset) {
 221         case offsetof(struct user_regs_struct, cs):
 222         case offsetof(struct user_regs_struct, ss):
 223                 if (unlikely(value == 0))
 224                         return -EIO;
 225                 fallthrough;
 226
 227         default:
 228                 *pt_regs_access(task_pt_regs(task), offset) = value;
 229                 break;
 230
 231         case offsetof(struct user_regs_struct, gs):
 232                 task->thread.gs = value;
 233         }
 234
 235         return 0;
 236 }
 237
 238 #else  /* CONFIG_X86_64 */
 239
 240 #define FLAG_MASK               (FLAG_MASK_32 | X86_EFLAGS_NT)
 241
 242 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
 243 {
 244         BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
 245         return &regs->r15 + (offset / sizeof(regs->r15));
 246 }
 247
 248 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
 249 {
 250         /*
 251          * Returning the value truncates it to 16 bits.
 252          */
 253         unsigned int seg;
 254
 255         switch (offset) {
 256         case offsetof(struct user_regs_struct, fs):
 257                 if (task == current) {
 258                         /* Older gas can't assemble movq %?s,%r?? */
 259                         asm("movl %%fs,%0" : "=r" (seg));
 260                         return seg;
 261                 }
 262                 return task->thread.fsindex;
 263         case offsetof(struct user_regs_struct, gs):
 264                 if (task == current) {
 265                         asm("movl %%gs,%0" : "=r" (seg));
 266                         return seg;
 267                 }
 268                 return task->thread.gsindex;
 269         case offsetof(struct user_regs_struct, ds):
 270                 if (task == current) {
 271                         asm("movl %%ds,%0" : "=r" (seg));
 272                         return seg;
 273                 }
 274                 return task->thread.ds;
 275         case offsetof(struct user_regs_struct, es):
 276                 if (task == current) {
 277                         asm("movl %%es,%0" : "=r" (seg));
 278                         return seg;
 279                 }
 280                 return task->thread.es;
 281
 282         case offsetof(struct user_regs_struct, cs):
 283         case offsetof(struct user_regs_struct, ss):
 284                 break;
 285         }
 286         return *pt_regs_access(task_pt_regs(task), offset);
 287 }
 288
 289 static int set_segment_reg(struct task_struct *task,
 290                            unsigned long offset, u16 value)
 291 {
 292         if (WARN_ON_ONCE(task == current))
 293                 return -EIO;
 294
 295         /*
 296          * The value argument was already truncated to 16 bits.
 297          */
 298         if (invalid_selector(value))
 299                 return -EIO;
 300
 301         /*
 302          * Writes to FS and GS will change the stored selector.  Whether
 303          * this changes the segment base as well depends on whether
 304          * FSGSBASE is enabled.
 305          */
 306
 307         switch (offset) {
 308         case offsetof(struct user_regs_struct,fs):
 309                 task->thread.fsindex = value;
 310                 break;
 311         case offsetof(struct user_regs_struct,gs):
 312                 task->thread.gsindex = value;
 313                 break;
 314         case offsetof(struct user_regs_struct,ds):
 315                 task->thread.ds = value;
 316                 break;
 317         case offsetof(struct user_regs_struct,es):
 318                 task->thread.es = value;
 319                 break;
 320
 321                 /*
 322                  * Can't actually change these in 64-bit mode.
 323                  */
 324         case offsetof(struct user_regs_struct,cs):
 325                 if (unlikely(value == 0))
 326                         return -EIO;
 327                 task_pt_regs(task)->cs = value;
 328                 break;
 329         case offsetof(struct user_regs_struct,ss):
 330                 if (unlikely(value == 0))
 331                         return -EIO;
 332                 task_pt_regs(task)->ss = value;
 333                 break;
 334         }
 335
 336         return 0;
 337 }
 338
 339 #endif  /* CONFIG_X86_32 */
 340
 341 static unsigned long get_flags(struct task_struct *task)
 342 {
 343         unsigned long retval = task_pt_regs(task)->flags;
 344
 345         /*
 346          * If the debugger set TF, hide it from the readout.
 347          */
 348         if (test_tsk_thread_flag(task, TIF_FORCED_TF))
 349                 retval &= ~X86_EFLAGS_TF;
 350
 351         return retval;
 352 }
 353
 354 static int set_flags(struct task_struct *task, unsigned long value)
 355 {
 356         struct pt_regs *regs = task_pt_regs(task);
 357
 358         /*
 359          * If the user value contains TF, mark that
 360          * it was not "us" (the debugger) that set it.
 361          * If not, make sure it stays set if we had.
 362          */
 363         if (value & X86_EFLAGS_TF)
 364                 clear_tsk_thread_flag(task, TIF_FORCED_TF);
 365         else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
 366                 value |= X86_EFLAGS_TF;
 367
 368         regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
 369
 370         return 0;
 371 }
 372
 373 static int putreg(struct task_struct *child,
 374                   unsigned long offset, unsigned long value)
 375 {
 376         switch (offset) {
 377         case offsetof(struct user_regs_struct, cs):
 378         case offsetof(struct user_regs_struct, ds):
 379         case offsetof(struct user_regs_struct, es):
 380         case offsetof(struct user_regs_struct, fs):
 381         case offsetof(struct user_regs_struct, gs):
 382         case offsetof(struct user_regs_struct, ss):
 383                 return set_segment_reg(child, offset, value);
 384
 385         case offsetof(struct user_regs_struct, flags):
 386                 return set_flags(child, value);
 387
 388 #ifdef CONFIG_X86_64
 389         case offsetof(struct user_regs_struct,fs_base):
 390                 if (value >= TASK_SIZE_MAX)
 391                         return -EIO;
 392                 x86_fsbase_write_task(child, value);
 393                 return 0;
 394         case offsetof(struct user_regs_struct,gs_base):
 395                 if (value >= TASK_SIZE_MAX)
 396                         return -EIO;
 397                 x86_gsbase_write_task(child, value);
 398                 return 0;
 399 #endif
 400         }
 401
 402         *pt_regs_access(task_pt_regs(child), offset) = value;
 403         return 0;
 404 }
 405
 406 static unsigned long getreg(struct task_struct *task, unsigned long offset)
 407 {
 408         switch (offset) {
 409         case offsetof(struct user_regs_struct, cs):
 410         case offsetof(struct user_regs_struct, ds):
 411         case offsetof(struct user_regs_struct, es):
 412         case offsetof(struct user_regs_struct, fs):
 413         case offsetof(struct user_regs_struct, gs):
 414         case offsetof(struct user_regs_struct, ss):
 415                 return get_segment_reg(task, offset);
 416
 417         case offsetof(struct user_regs_struct, flags):
 418                 return get_flags(task);
 419
 420 #ifdef CONFIG_X86_64
 421         case offsetof(struct user_regs_struct, fs_base):
 422                 return x86_fsbase_read_task(task);
 423         case offsetof(struct user_regs_struct, gs_base):
 424                 return x86_gsbase_read_task(task);
 425 #endif
 426         }
 427
 428         return *pt_regs_access(task_pt_regs(task), offset);
 429 }
 430
 431 static int genregs_get(struct task_struct *target,
 432                        const struct user_regset *regset,
 433                        struct membuf to)
 434 {
 435         int reg;
 436
 437         for (reg = 0; to.left; reg++)
 438                 membuf_store(&to, getreg(target, reg * sizeof(unsigned long)));
 439         return 0;
 440 }
 441
 442 static int genregs_set(struct task_struct *target,
 443                        const struct user_regset *regset,
 444                        unsigned int pos, unsigned int count,
 445                        const void *kbuf, const void __user *ubuf)
 446 {
 447         int ret = 0;
 448         if (kbuf) {
 449                 const unsigned long *k = kbuf;
 450                 while (count >= sizeof(*k) && !ret) {
 451                         ret = putreg(target, pos, *k++);
 452                         count -= sizeof(*k);
 453                         pos += sizeof(*k);
 454                 }
 455         } else {
 456                 const unsigned long  __user *u = ubuf;
 457                 while (count >= sizeof(*u) && !ret) {
 458                         unsigned long word;
 459                         ret = __get_user(word, u++);
 460                         if (ret)
 461                                 break;
 462                         ret = putreg(target, pos, word);
 463                         count -= sizeof(*u);
 464                         pos += sizeof(*u);
 465                 }
 466         }
 467         return ret;
 468 }
 469
 470 static void ptrace_triggered(struct perf_event *bp,
 471                              struct perf_sample_data *data,
 472                              struct pt_regs *regs)
 473 {
 474         int i;
 475         struct thread_struct *thread = &(current->thread);
 476
 477         /*
 478          * Store in the virtual DR6 register the fact that the breakpoint
 479          * was hit so the thread's debugger will see it.
 480          */
 481         for (i = 0; i < HBP_NUM; i++) {
 482                 if (thread->ptrace_bps[i] == bp)
 483                         break;
 484         }
 485
 486         thread->virtual_dr6 |= (DR_TRAP0 << i);
 487 }
 488
 489 /*
 490  * Walk through every ptrace breakpoints for this thread and
 491  * build the dr7 value on top of their attributes.
 492  *
 493  */
 494 static unsigned long ptrace_get_dr7(struct perf_event *bp[])
 495 {
 496         int i;
 497         int dr7 = 0;
 498         struct arch_hw_breakpoint *info;
 499
 500         for (i = 0; i < HBP_NUM; i++) {
 501                 if (bp[i] && !bp[i]->attr.disabled) {
 502                         info = counter_arch_bp(bp[i]);
 503                         dr7 |= encode_dr7(i, info->len, info->type);
 504                 }
 505         }
 506
 507         return dr7;
 508 }
 509
 510 static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
 511                                         int len, int type, bool disabled)
 512 {
 513         int err, bp_len, bp_type;
 514
 515         err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);
 516         if (!err) {
 517                 attr->bp_len = bp_len;
 518                 attr->bp_type = bp_type;
 519                 attr->disabled = disabled;
 520         }
 521
 522         return err;
 523 }
 524
 525 static struct perf_event *
 526 ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,
 527                                 unsigned long addr, bool disabled)
 528 {
 529         struct perf_event_attr attr;
 530         int err;
 531
 532         ptrace_breakpoint_init(&attr);
 533         attr.bp_addr = addr;
 534
 535         err = ptrace_fill_bp_fields(&attr, len, type, disabled);
 536         if (err)
 537                 return ERR_PTR(err);
 538
 539         return register_user_hw_breakpoint(&attr, ptrace_triggered,
 540                                                  NULL, tsk);
 541 }
 542
 543 static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
 544                                         int disabled)
 545 {
 546         struct perf_event_attr attr = bp->attr;
 547         int err;
 548
 549         err = ptrace_fill_bp_fields(&attr, len, type, disabled);
 550         if (err)
 551                 return err;
 552
 553         return modify_user_hw_breakpoint(bp, &attr);
 554 }
 555
 556 /*
 557  * Handle ptrace writes to debug register 7.
 558  */
 559 static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
 560 {
 561         struct thread_struct *thread = &tsk->thread;
 562         unsigned long old_dr7;
 563         bool second_pass = false;
 564         int i, rc, ret = 0;
 565
 566         data &= ~DR_CONTROL_RESERVED;
 567         old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
 568
 569 restore:
 570         rc = 0;
 571         for (i = 0; i < HBP_NUM; i++) {
 572                 unsigned len, type;
 573                 bool disabled = !decode_dr7(data, i, &len, &type);
 574                 struct perf_event *bp = thread->ptrace_bps[i];
 575
 576                 if (!bp) {
 577                         if (disabled)
 578                                 continue;
 579
 580                         bp = ptrace_register_breakpoint(tsk,
 581                                         len, type, 0, disabled);
 582                         if (IS_ERR(bp)) {
 583                                 rc = PTR_ERR(bp);
 584                                 break;
 585                         }
 586
 587                         thread->ptrace_bps[i] = bp;
 588                         continue;
 589                 }
 590
 591                 rc = ptrace_modify_breakpoint(bp, len, type, disabled);
 592                 if (rc)
 593                         break;
 594         }
 595
 596         /* Restore if the first pass failed, second_pass shouldn't fail. */
 597         if (rc && !WARN_ON(second_pass)) {
 598                 ret = rc;
 599                 data = old_dr7;
 600                 second_pass = true;
 601                 goto restore;
 602         }
 603
 604         return ret;
 605 }
 606
 607 /*
 608  * Handle PTRACE_PEEKUSR calls for the debug register area.
 609  */
 610 static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
 611 {
 612         struct thread_struct *thread = &tsk->thread;
 613         unsigned long val = 0;
 614
 615         if (n < HBP_NUM) {
 616                 int index = array_index_nospec(n, HBP_NUM);
 617                 struct perf_event *bp = thread->ptrace_bps[index];
 618
 619                 if (bp)
 620                         val = bp->hw.info.address;
 621         } else if (n == 6) {
 622                 val = thread->virtual_dr6 ^ DR6_RESERVED; /* Flip back to arch polarity */
 623         } else if (n == 7) {
 624                 val = thread->ptrace_dr7;
 625         }
 626         return val;
 627 }
 628
 629 static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
 630                                       unsigned long addr)
 631 {
 632         struct thread_struct *t = &tsk->thread;
 633         struct perf_event *bp = t->ptrace_bps[nr];
 634         int err = 0;
 635
 636         if (!bp) {
 637                 /*
 638                  * Put stub len and type to create an inactive but correct bp.
 639                  *
 640                  * CHECKME: the previous code returned -EIO if the addr wasn't
 641                  * a valid task virtual addr. The new one will return -EINVAL in
 642                  *  this case.
 643                  * -EINVAL may be what we want for in-kernel breakpoints users,
 644                  * but -EIO looks better for ptrace, since we refuse a register
 645                  * writing for the user. And anyway this is the previous
 646                  * behaviour.
 647                  */
 648                 bp = ptrace_register_breakpoint(tsk,
 649                                 X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
 650                                 addr, true);
 651                 if (IS_ERR(bp))
 652                         err = PTR_ERR(bp);
 653                 else
 654                         t->ptrace_bps[nr] = bp;
 655         } else {
 656                 struct perf_event_attr attr = bp->attr;
 657
 658                 attr.bp_addr = addr;
 659                 err = modify_user_hw_breakpoint(bp, &attr);
 660         }
 661
 662         return err;
 663 }
 664
 665 /*
 666  * Handle PTRACE_POKEUSR calls for the debug register area.
 667  */
 668 static int ptrace_set_debugreg(struct task_struct *tsk, int n,
 669                                unsigned long val)
 670 {
 671         struct thread_struct *thread = &tsk->thread;
 672         /* There are no DR4 or DR5 registers */
 673         int rc = -EIO;
 674
 675         if (n < HBP_NUM) {
 676                 rc = ptrace_set_breakpoint_addr(tsk, n, val);
 677         } else if (n == 6) {
 678                 thread->virtual_dr6 = val ^ DR6_RESERVED; /* Flip to positive polarity */
 679                 rc = 0;
 680         } else if (n == 7) {
 681                 rc = ptrace_write_dr7(tsk, val);
 682                 if (!rc)
 683                         thread->ptrace_dr7 = val;
 684         }
 685         return rc;
 686 }
 687
 688 /*
 689  * These access the current or another (stopped) task's io permission
 690  * bitmap for debugging or core dump.
 691  */
 692 static int ioperm_active(struct task_struct *target,
 693                          const struct user_regset *regset)
 694 {
 695         struct io_bitmap *iobm = target->thread.io_bitmap;
 696
 697         return iobm ? DIV_ROUND_UP(iobm->max, regset->size) : 0;
 698 }
 699
 700 static int ioperm_get(struct task_struct *target,
 701                       const struct user_regset *regset,
 702                       struct membuf to)
 703 {
 704         struct io_bitmap *iobm = target->thread.io_bitmap;
 705
 706         if (!iobm)
 707                 return -ENXIO;
 708
 709         return membuf_write(&to, iobm->bitmap, IO_BITMAP_BYTES);
 710 }
 711
 712 /*
 713  * Called by kernel/ptrace.c when detaching..
 714  *
 715  * Make sure the single step bit is not set.
 716  */
 717 void ptrace_disable(struct task_struct *child)
 718 {
 719         user_disable_single_step(child);
 720 }
 721
 722 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 723 static const struct user_regset_view user_x86_32_view; /* Initialized below. */
 724 #endif
 725 #ifdef CONFIG_X86_64
 726 static const struct user_regset_view user_x86_64_view; /* Initialized below. */
 727 #endif
 728
 729 long arch_ptrace(struct task_struct *child, long request,
 730                  unsigned long addr, unsigned long data)
 731 {
 732         int ret;
 733         unsigned long __user *datap = (unsigned long __user *)data;
 734
 735 #ifdef CONFIG_X86_64
 736         /* This is native 64-bit ptrace() */
 737         const struct user_regset_view *regset_view = &user_x86_64_view;
 738 #else
 739         /* This is native 32-bit ptrace() */
 740         const struct user_regset_view *regset_view = &user_x86_32_view;
 741 #endif
 742
 743         switch (request) {
 744         /* read the word at location addr in the USER area. */
 745         case PTRACE_PEEKUSR: {
 746                 unsigned long tmp;
 747
 748                 ret = -EIO;
 749                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
 750                         break;
 751
 752                 tmp = 0;  /* Default return condition */
 753                 if (addr < sizeof(struct user_regs_struct))
 754                         tmp = getreg(child, addr);
 755                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
 756                          addr <= offsetof(struct user, u_debugreg[7])) {
 757                         addr -= offsetof(struct user, u_debugreg[0]);
 758                         tmp = ptrace_get_debugreg(child, addr / sizeof(data));
 759                 }
 760                 ret = put_user(tmp, datap);
 761                 break;
 762         }
 763
 764         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 765                 ret = -EIO;
 766                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
 767                         break;
 768
 769                 if (addr < sizeof(struct user_regs_struct))
 770                         ret = putreg(child, addr, data);
 771                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
 772                          addr <= offsetof(struct user, u_debugreg[7])) {
 773                         addr -= offsetof(struct user, u_debugreg[0]);
 774                         ret = ptrace_set_debugreg(child,
 775                                                   addr / sizeof(data), data);
 776                 }
 777                 break;
 778
 779         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 780                 return copy_regset_to_user(child,
 781                                            regset_view,
 782                                            REGSET_GENERAL,
 783                                            0, sizeof(struct user_regs_struct),
 784                                            datap);
 785
 786         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 787                 return copy_regset_from_user(child,
 788                                              regset_view,
 789                                              REGSET_GENERAL,
 790                                              0, sizeof(struct user_regs_struct),
 791                                              datap);
 792
 793         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 794                 return copy_regset_to_user(child,
 795                                            regset_view,
 796                                            REGSET_FP,
 797                                            0, sizeof(struct user_i387_struct),
 798                                            datap);
 799
 800         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 801                 return copy_regset_from_user(child,
 802                                              regset_view,
 803                                              REGSET_FP,
 804                                              0, sizeof(struct user_i387_struct),
 805                                              datap);
 806
 807 #ifdef CONFIG_X86_32
 808         case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
 809                 return copy_regset_to_user(child, &user_x86_32_view,
 810                                            REGSET32_XFP,
 811                                            0, sizeof(struct user_fxsr_struct),
 812                                            datap) ? -EIO : 0;
 813
 814         case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
 815                 return copy_regset_from_user(child, &user_x86_32_view,
 816                                              REGSET32_XFP,
 817                                              0, sizeof(struct user_fxsr_struct),
 818                                              datap) ? -EIO : 0;
 819 #endif
 820
 821 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 822         case PTRACE_GET_THREAD_AREA:
 823                 if ((int) addr < 0)
 824                         return -EIO;
 825                 ret = do_get_thread_area(child, addr,
 826                                         (struct user_desc __user *)data);
 827                 break;
 828
 829         case PTRACE_SET_THREAD_AREA:
 830                 if ((int) addr < 0)
 831                         return -EIO;
 832                 ret = do_set_thread_area(child, addr,
 833                                         (struct user_desc __user *)data, 0);
 834                 break;
 835 #endif
 836
 837 #ifdef CONFIG_X86_64
 838                 /* normal 64bit interface to access TLS data.
 839                    Works just like arch_prctl, except that the arguments
 840                    are reversed. */
 841         case PTRACE_ARCH_PRCTL:
 842                 ret = do_arch_prctl_64(child, data, addr);
 843                 break;
 844 #endif
 845
 846         default:
 847                 ret = ptrace_request(child, request, addr, data);
 848                 break;
 849         }
 850
 851         return ret;
 852 }
 853
 854 #ifdef CONFIG_IA32_EMULATION
 855
 856 #include <linux/compat.h>
 857 #include <linux/syscalls.h>
 858 #include <asm/ia32.h>
 859 #include <asm/user32.h>
 860
 861 #define R32(l,q)                                                        \
 862         case offsetof(struct user32, regs.l):                           \
 863                 regs->q = value; break
 864
 865 #define SEG32(rs)                                                       \
 866         case offsetof(struct user32, regs.rs):                          \
 867                 return set_segment_reg(child,                           \
 868                                        offsetof(struct user_regs_struct, rs), \
 869                                        value);                          \
 870                 break
 871
 872 static int putreg32(struct task_struct *child, unsigned regno, u32 value)
 873 {
 874         struct pt_regs *regs = task_pt_regs(child);
 875         int ret;
 876
 877         switch (regno) {
 878
 879         SEG32(cs);
 880         SEG32(ds);
 881         SEG32(es);
 882
 883         /*
 884          * A 32-bit ptracer on a 64-bit kernel expects that writing
 885          * FS or GS will also update the base.  This is needed for
 886          * operations like PTRACE_SETREGS to fully restore a saved
 887          * CPU state.
 888          */
 889
 890         case offsetof(struct user32, regs.fs):
 891                 ret = set_segment_reg(child,
 892                                       offsetof(struct user_regs_struct, fs),
 893                                       value);
 894                 if (ret == 0)
 895                         child->thread.fsbase =
 896                                 x86_fsgsbase_read_task(child, value);
 897                 return ret;
 898
 899         case offsetof(struct user32, regs.gs):
 900                 ret = set_segment_reg(child,
 901                                       offsetof(struct user_regs_struct, gs),
 902                                       value);
 903                 if (ret == 0)
 904                         child->thread.gsbase =
 905                                 x86_fsgsbase_read_task(child, value);
 906                 return ret;
 907
 908         SEG32(ss);
 909
 910         R32(ebx, bx);
 911         R32(ecx, cx);
 912         R32(edx, dx);
 913         R32(edi, di);
 914         R32(esi, si);
 915         R32(ebp, bp);
 916         R32(eax, ax);
 917         R32(eip, ip);
 918         R32(esp, sp);
 919
 920         case offsetof(struct user32, regs.orig_eax):
 921                 /*
 922                  * Warning: bizarre corner case fixup here.  A 32-bit
 923                  * debugger setting orig_eax to -1 wants to disable
 924                  * syscall restart.  Make sure that the syscall
 925                  * restart code sign-extends orig_ax.  Also make sure
 926                  * we interpret the -ERESTART* codes correctly if
 927                  * loaded into regs->ax in case the task is not
 928                  * actually still sitting at the exit from a 32-bit
 929                  * syscall with TS_COMPAT still set.
 930                  */
 931                 regs->orig_ax = value;
 932                 if (syscall_get_nr(child, regs) != -1)
 933                         child->thread_info.status |= TS_I386_REGS_POKED;
 934                 break;
 935
 936         case offsetof(struct user32, regs.eflags):
 937                 return set_flags(child, value);
 938
 939         case offsetof(struct user32, u_debugreg[0]) ...
 940                 offsetof(struct user32, u_debugreg[7]):
 941                 regno -= offsetof(struct user32, u_debugreg[0]);
 942                 return ptrace_set_debugreg(child, regno / 4, value);
 943
 944         default:
 945                 if (regno > sizeof(struct user32) || (regno & 3))
 946                         return -EIO;
 947
 948                 /*
 949                  * Other dummy fields in the virtual user structure
 950                  * are ignored
 951                  */
 952                 break;
 953         }
 954         return 0;
 955 }
 956
 957 #undef R32
 958 #undef SEG32
 959
 960 #define R32(l,q)                                                        \
 961         case offsetof(struct user32, regs.l):                           \
 962                 *val = regs->q; break
 963
 964 #define SEG32(rs)                                                       \
 965         case offsetof(struct user32, regs.rs):                          \
 966                 *val = get_segment_reg(child,                           \
 967                                        offsetof(struct user_regs_struct, rs)); \
 968                 break
 969
 970 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
 971 {
 972         struct pt_regs *regs = task_pt_regs(child);
 973
 974         switch (regno) {
 975
 976         SEG32(ds);
 977         SEG32(es);
 978         SEG32(fs);
 979         SEG32(gs);
 980
 981         R32(cs, cs);
 982         R32(ss, ss);
 983         R32(ebx, bx);
 984         R32(ecx, cx);
 985         R32(edx, dx);
 986         R32(edi, di);
 987         R32(esi, si);
 988         R32(ebp, bp);
 989         R32(eax, ax);
 990         R32(orig_eax, orig_ax);
 991         R32(eip, ip);
 992         R32(esp, sp);
 993
 994         case offsetof(struct user32, regs.eflags):
 995                 *val = get_flags(child);
 996                 break;
 997
 998         case offsetof(struct user32, u_debugreg[0]) ...
 999                 offsetof(struct user32, u_debugreg[7]):
1000                 regno -= offsetof(struct user32, u_debugreg[0]);
1001                 *val = ptrace_get_debugreg(child, regno / 4);
1002                 break;
1003
1004         default:
1005                 if (regno > sizeof(struct user32) || (regno & 3))
1006                         return -EIO;
1007
1008                 /*
1009                  * Other dummy fields in the virtual user structure
1010                  * are ignored
1011                  */
1012                 *val = 0;
1013                 break;
1014         }
1015         return 0;
1016 }
1017
1018 #undef R32
1019 #undef SEG32
1020
1021 static int genregs32_get(struct task_struct *target,
1022                          const struct user_regset *regset,
1023                          struct membuf to)
1024 {
1025         int reg;
1026
1027         for (reg = 0; to.left; reg++) {
1028                 u32 val;
1029                 getreg32(target, reg * 4, &val);
1030                 membuf_store(&to, val);
1031         }
1032         return 0;
1033 }
1034
1035 static int genregs32_set(struct task_struct *target,
1036                          const struct user_regset *regset,
1037                          unsigned int pos, unsigned int count,
1038                          const void *kbuf, const void __user *ubuf)
1039 {
1040         int ret = 0;
1041         if (kbuf) {
1042                 const compat_ulong_t *k = kbuf;
1043                 while (count >= sizeof(*k) && !ret) {
1044                         ret = putreg32(target, pos, *k++);
1045                         count -= sizeof(*k);
1046                         pos += sizeof(*k);
1047                 }
1048         } else {
1049                 const compat_ulong_t __user *u = ubuf;
1050                 while (count >= sizeof(*u) && !ret) {
1051                         compat_ulong_t word;
1052                         ret = __get_user(word, u++);
1053                         if (ret)
1054                                 break;
1055                         ret = putreg32(target, pos, word);
1056                         count -= sizeof(*u);
1057                         pos += sizeof(*u);
1058                 }
1059         }
1060         return ret;
1061 }
1062
1063 static long ia32_arch_ptrace(struct task_struct *child, compat_long_t request,
1064                              compat_ulong_t caddr, compat_ulong_t cdata)
1065 {
1066         unsigned long addr = caddr;
1067         unsigned long data = cdata;
1068         void __user *datap = compat_ptr(data);
1069         int ret;
1070         __u32 val;
1071
1072         switch (request) {
1073         case PTRACE_PEEKUSR:
1074                 ret = getreg32(child, addr, &val);
1075                 if (ret == 0)
1076                         ret = put_user(val, (__u32 __user *)datap);
1077                 break;
1078
1079         case PTRACE_POKEUSR:
1080                 ret = putreg32(child, addr, data);
1081                 break;
1082
1083         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
1084                 return copy_regset_to_user(child, &user_x86_32_view,
1085                                            REGSET_GENERAL,
1086                                            0, sizeof(struct user_regs_struct32),
1087                                            datap);
1088
1089         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
1090                 return copy_regset_from_user(child, &user_x86_32_view,
1091                                              REGSET_GENERAL, 0,
1092                                              sizeof(struct user_regs_struct32),
1093                                              datap);
1094
1095         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
1096                 return copy_regset_to_user(child, &user_x86_32_view,
1097                                            REGSET_FP, 0,
1098                                            sizeof(struct user_i387_ia32_struct),
1099                                            datap);
1100
1101         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
1102                 return copy_regset_from_user(
1103                         child, &user_x86_32_view, REGSET_FP,
1104                         0, sizeof(struct user_i387_ia32_struct), datap);
1105
1106         case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
1107                 return copy_regset_to_user(child, &user_x86_32_view,
1108                                            REGSET32_XFP, 0,
1109                                            sizeof(struct user32_fxsr_struct),
1110                                            datap);
1111
1112         case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
1113                 return copy_regset_from_user(child, &user_x86_32_view,
1114                                              REGSET32_XFP, 0,
1115                                              sizeof(struct user32_fxsr_struct),
1116                                              datap);
1117
1118         case PTRACE_GET_THREAD_AREA:
1119         case PTRACE_SET_THREAD_AREA:
1120                 return arch_ptrace(child, request, addr, data);
1121
1122         default:
1123                 return compat_ptrace_request(child, request, addr, data);
1124         }
1125
1126         return ret;
1127 }
1128 #endif /* CONFIG_IA32_EMULATION */
1129
1130 #ifdef CONFIG_X86_X32_ABI
1131 static long x32_arch_ptrace(struct task_struct *child,
1132                             compat_long_t request, compat_ulong_t caddr,
1133                             compat_ulong_t cdata)
1134 {
1135         unsigned long addr = caddr;
1136         unsigned long data = cdata;
1137         void __user *datap = compat_ptr(data);
1138         int ret;
1139
1140         switch (request) {
1141         /* Read 32bits at location addr in the USER area.  Only allow
1142            to return the lower 32bits of segment and debug registers.  */
1143         case PTRACE_PEEKUSR: {
1144                 u32 tmp;
1145
1146                 ret = -EIO;
1147                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1148                     addr < offsetof(struct user_regs_struct, cs))
1149                         break;
1150
1151                 tmp = 0;  /* Default return condition */
1152                 if (addr < sizeof(struct user_regs_struct))
1153                         tmp = getreg(child, addr);
1154                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1155                          addr <= offsetof(struct user, u_debugreg[7])) {
1156                         addr -= offsetof(struct user, u_debugreg[0]);
1157                         tmp = ptrace_get_debugreg(child, addr / sizeof(data));
1158                 }
1159                 ret = put_user(tmp, (__u32 __user *)datap);
1160                 break;
1161         }
1162
1163         /* Write the word at location addr in the USER area.  Only allow
1164            to update segment and debug registers with the upper 32bits
1165            zero-extended. */
1166         case PTRACE_POKEUSR:
1167                 ret = -EIO;
1168                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1169                     addr < offsetof(struct user_regs_struct, cs))
1170                         break;
1171
1172                 if (addr < sizeof(struct user_regs_struct))
1173                         ret = putreg(child, addr, data);
1174                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1175                          addr <= offsetof(struct user, u_debugreg[7])) {
1176                         addr -= offsetof(struct user, u_debugreg[0]);
1177                         ret = ptrace_set_debugreg(child,
1178                                                   addr / sizeof(data), data);
1179                 }
1180                 break;
1181
1182         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
1183                 return copy_regset_to_user(child,
1184                                            &user_x86_64_view,
1185                                            REGSET_GENERAL,
1186                                            0, sizeof(struct user_regs_struct),
1187                                            datap);
1188
1189         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
1190                 return copy_regset_from_user(child,
1191                                              &user_x86_64_view,
1192                                              REGSET_GENERAL,
1193                                              0, sizeof(struct user_regs_struct),
1194                                              datap);
1195
1196         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
1197                 return copy_regset_to_user(child,
1198                                            &user_x86_64_view,
1199                                            REGSET_FP,
1200                                            0, sizeof(struct user_i387_struct),
1201                                            datap);
1202
1203         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
1204                 return copy_regset_from_user(child,
1205                                              &user_x86_64_view,
1206                                              REGSET_FP,
1207                                              0, sizeof(struct user_i387_struct),
1208                                              datap);
1209
1210         default:
1211                 return compat_ptrace_request(child, request, addr, data);
1212         }
1213
1214         return ret;
1215 }
1216 #endif
1217
1218 #ifdef CONFIG_COMPAT
1219 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1220                         compat_ulong_t caddr, compat_ulong_t cdata)
1221 {
1222 #ifdef CONFIG_X86_X32_ABI
1223         if (!in_ia32_syscall())
1224                 return x32_arch_ptrace(child, request, caddr, cdata);
1225 #endif
1226 #ifdef CONFIG_IA32_EMULATION
1227         return ia32_arch_ptrace(child, request, caddr, cdata);
1228 #else
1229         return 0;
1230 #endif
1231 }
1232 #endif  /* CONFIG_COMPAT */
1233
1234 #ifdef CONFIG_X86_64
1235
1236 static struct user_regset x86_64_regsets[] __ro_after_init = {
1237         [REGSET64_GENERAL] = {
1238                 .core_note_type = NT_PRSTATUS,
1239                 .n              = sizeof(struct user_regs_struct) / sizeof(long),
1240                 .size           = sizeof(long),
1241                 .align          = sizeof(long),
1242                 .regset_get     = genregs_get,
1243                 .set            = genregs_set
1244         },
1245         [REGSET64_FP] = {
1246                 .core_note_type = NT_PRFPREG,
1247                 .n              = sizeof(struct fxregs_state) / sizeof(long),
1248                 .size           = sizeof(long),
1249                 .align          = sizeof(long),
1250                 .active         = regset_xregset_fpregs_active,
1251                 .regset_get     = xfpregs_get,
1252                 .set            = xfpregs_set
1253         },
1254         [REGSET64_XSTATE] = {
1255                 .core_note_type = NT_X86_XSTATE,
1256                 .size           = sizeof(u64),
1257                 .align          = sizeof(u64),
1258                 .active         = xstateregs_active,
1259                 .regset_get     = xstateregs_get,
1260                 .set            = xstateregs_set
1261         },
1262         [REGSET64_IOPERM] = {
1263                 .core_note_type = NT_386_IOPERM,
1264                 .n              = IO_BITMAP_LONGS,
1265                 .size           = sizeof(long),
1266                 .align          = sizeof(long),
1267                 .active         = ioperm_active,
1268                 .regset_get     = ioperm_get
1269         },
1270 };
1271
1272 static const struct user_regset_view user_x86_64_view = {
1273         .name = "x86_64", .e_machine = EM_X86_64,
1274         .regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
1275 };
1276
1277 #else  /* CONFIG_X86_32 */
1278
1279 #define user_regs_struct32      user_regs_struct
1280 #define genregs32_get           genregs_get
1281 #define genregs32_set           genregs_set
1282
1283 #endif  /* CONFIG_X86_64 */
1284
1285 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1286 static struct user_regset x86_32_regsets[] __ro_after_init = {
1287         [REGSET32_GENERAL] = {
1288                 .core_note_type = NT_PRSTATUS,
1289                 .n              = sizeof(struct user_regs_struct32) / sizeof(u32),
1290                 .size           = sizeof(u32),
1291                 .align          = sizeof(u32),
1292                 .regset_get     = genregs32_get,
1293                 .set            = genregs32_set
1294         },
1295         [REGSET32_FP] = {
1296                 .core_note_type = NT_PRFPREG,
1297                 .n              = sizeof(struct user_i387_ia32_struct) / sizeof(u32),
1298                 .size           = sizeof(u32),
1299                 .align          = sizeof(u32),
1300                 .active         = regset_fpregs_active,
1301                 .regset_get     = fpregs_get,
1302                 .set            = fpregs_set
1303         },
1304         [REGSET32_XFP] = {
1305                 .core_note_type = NT_PRXFPREG,
1306                 .n              = sizeof(struct fxregs_state) / sizeof(u32),
1307                 .size           = sizeof(u32),
1308                 .align          = sizeof(u32),
1309                 .active         = regset_xregset_fpregs_active,
1310                 .regset_get     = xfpregs_get,
1311                 .set            = xfpregs_set
1312         },
1313         [REGSET32_XSTATE] = {
1314                 .core_note_type = NT_X86_XSTATE,
1315                 .size           = sizeof(u64),
1316                 .align          = sizeof(u64),
1317                 .active         = xstateregs_active,
1318                 .regset_get     = xstateregs_get,
1319                 .set            = xstateregs_set
1320         },
1321         [REGSET32_TLS] = {
1322                 .core_note_type = NT_386_TLS,
1323                 .n              = GDT_ENTRY_TLS_ENTRIES,
1324                 .bias           = GDT_ENTRY_TLS_MIN,
1325                 .size           = sizeof(struct user_desc),
1326                 .align          = sizeof(struct user_desc),
1327                 .active         = regset_tls_active,
1328                 .regset_get     = regset_tls_get,
1329                 .set            = regset_tls_set
1330         },
1331         [REGSET32_IOPERM] = {
1332                 .core_note_type = NT_386_IOPERM,
1333                 .n              = IO_BITMAP_BYTES / sizeof(u32),
1334                 .size           = sizeof(u32),
1335                 .align          = sizeof(u32),
1336                 .active         = ioperm_active,
1337                 .regset_get     = ioperm_get
1338         },
1339 };
1340
1341 static const struct user_regset_view user_x86_32_view = {
1342         .name = "i386", .e_machine = EM_386,
1343         .regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
1344 };
1345 #endif
1346
1347 /*
1348  * This represents bytes 464..511 in the memory layout exported through
1349  * the REGSET_XSTATE interface.
1350  */
1351 u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
1352
1353 void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask)
1354 {
1355 #ifdef CONFIG_X86_64
1356         x86_64_regsets[REGSET64_XSTATE].n = size / sizeof(u64);
1357 #endif
1358 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1359         x86_32_regsets[REGSET32_XSTATE].n = size / sizeof(u64);
1360 #endif
1361         xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
1362 }
1363
1364 /*
1365  * This is used by the core dump code to decide which regset to dump.  The
1366  * core dump code writes out the resulting .e_machine and the corresponding
1367  * regsets.  This is suboptimal if the task is messing around with its CS.L
1368  * field, but at worst the core dump will end up missing some information.
1369  *
1370  * Unfortunately, it is also used by the broken PTRACE_GETREGSET and
1371  * PTRACE_SETREGSET APIs.  These APIs look at the .regsets field but have
1372  * no way to make sure that the e_machine they use matches the caller's
1373  * expectations.  The result is that the data format returned by
1374  * PTRACE_GETREGSET depends on the returned CS field (and even the offset
1375  * of the returned CS field depends on its value!) and the data format
1376  * accepted by PTRACE_SETREGSET is determined by the old CS value.  The
1377  * upshot is that it is basically impossible to use these APIs correctly.
1378  *
1379  * The best way to fix it in the long run would probably be to add new
1380  * improved ptrace() APIs to read and write registers reliably, possibly by
1381  * allowing userspace to select the ELF e_machine variant that they expect.
1382  */
1383 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1384 {
1385 #ifdef CONFIG_IA32_EMULATION
1386         if (!user_64bit_mode(task_pt_regs(task)))
1387 #endif
1388 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1389                 return &user_x86_32_view;
1390 #endif
1391 #ifdef CONFIG_X86_64
1392         return &user_x86_64_view;
1393 #endif
1394 }
1395
1396 void send_sigtrap(struct pt_regs *regs, int error_code, int si_code)
1397 {
1398         struct task_struct *tsk = current;
1399
1400         tsk->thread.trap_nr = X86_TRAP_DB;
1401         tsk->thread.error_code = error_code;
1402
1403         /* Send us the fake SIGTRAP */
1404         force_sig_fault(SIGTRAP, si_code,
1405                         user_mode(regs) ? (void __user *)regs->ip : NULL);
1406 }
1407
1408 void user_single_step_report(struct pt_regs *regs)
1409 {
1410         send_sigtrap(regs, 0, TRAP_BRKPT);
1411 }