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 <gareth@valinux.com>, 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         REGSET64_SSP,
  62 };
  63
  64 #define REGSET_GENERAL \
  65 ({ \
  66         BUILD_BUG_ON((int)REGSET32_GENERAL != (int)REGSET64_GENERAL); \
  67         REGSET32_GENERAL; \
  68 })
  69
  70 #define REGSET_FP \
  71 ({ \
  72         BUILD_BUG_ON((int)REGSET32_FP != (int)REGSET64_FP); \
  73         REGSET32_FP; \
  74 })
  75
  76
  77 struct pt_regs_offset {
  78         const char *name;
  79         int offset;
  80 };
  81
  82 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
  83 #define REG_OFFSET_END {.name = NULL, .offset = 0}
  84
  85 static const struct pt_regs_offset regoffset_table[] = {
  86 #ifdef CONFIG_X86_64
  87         REG_OFFSET_NAME(r15),
  88         REG_OFFSET_NAME(r14),
  89         REG_OFFSET_NAME(r13),
  90         REG_OFFSET_NAME(r12),
  91         REG_OFFSET_NAME(r11),
  92         REG_OFFSET_NAME(r10),
  93         REG_OFFSET_NAME(r9),
  94         REG_OFFSET_NAME(r8),
  95 #endif
  96         REG_OFFSET_NAME(bx),
  97         REG_OFFSET_NAME(cx),
  98         REG_OFFSET_NAME(dx),
  99         REG_OFFSET_NAME(si),
 100         REG_OFFSET_NAME(di),
 101         REG_OFFSET_NAME(bp),
 102         REG_OFFSET_NAME(ax),
 103 #ifdef CONFIG_X86_32
 104         REG_OFFSET_NAME(ds),
 105         REG_OFFSET_NAME(es),
 106         REG_OFFSET_NAME(fs),
 107         REG_OFFSET_NAME(gs),
 108 #endif
 109         REG_OFFSET_NAME(orig_ax),
 110         REG_OFFSET_NAME(ip),
 111         REG_OFFSET_NAME(cs),
 112         REG_OFFSET_NAME(flags),
 113         REG_OFFSET_NAME(sp),
 114         REG_OFFSET_NAME(ss),
 115         REG_OFFSET_END,
 116 };
 117
 118 /**
 119  * regs_query_register_offset() - query register offset from its name
 120  * @name:       the name of a register
 121  *
 122  * regs_query_register_offset() returns the offset of a register in struct
 123  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 124  */
 125 int regs_query_register_offset(const char *name)
 126 {
 127         const struct pt_regs_offset *roff;
 128         for (roff = regoffset_table; roff->name != NULL; roff++)
 129                 if (!strcmp(roff->name, name))
 130                         return roff->offset;
 131         return -EINVAL;
 132 }
 133
 134 /**
 135  * regs_query_register_name() - query register name from its offset
 136  * @offset:     the offset of a register in struct pt_regs.
 137  *
 138  * regs_query_register_name() returns the name of a register from its
 139  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
 140  */
 141 const char *regs_query_register_name(unsigned int offset)
 142 {
 143         const struct pt_regs_offset *roff;
 144         for (roff = regoffset_table; roff->name != NULL; roff++)
 145                 if (roff->offset == offset)
 146                         return roff->name;
 147         return NULL;
 148 }
 149
 150 /*
 151  * does not yet catch signals sent when the child dies.
 152  * in exit.c or in signal.c.
 153  */
 154
 155 /*
 156  * Determines which flags the user has access to [1 = access, 0 = no access].
 157  */
 158 #define FLAG_MASK_32            ((unsigned long)                        \
 159                                  (X86_EFLAGS_CF | X86_EFLAGS_PF |       \
 160                                   X86_EFLAGS_AF | X86_EFLAGS_ZF |       \
 161                                   X86_EFLAGS_SF | X86_EFLAGS_TF |       \
 162                                   X86_EFLAGS_DF | X86_EFLAGS_OF |       \
 163                                   X86_EFLAGS_RF | X86_EFLAGS_AC))
 164
 165 /*
 166  * Determines whether a value may be installed in a segment register.
 167  */
 168 static inline bool invalid_selector(u16 value)
 169 {
 170         return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
 171 }
 172
 173 #ifdef CONFIG_X86_32
 174
 175 #define FLAG_MASK               FLAG_MASK_32
 176
 177 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
 178 {
 179         BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
 180         return &regs->bx + (regno >> 2);
 181 }
 182
 183 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
 184 {
 185         /*
 186          * Returning the value truncates it to 16 bits.
 187          */
 188         unsigned int retval;
 189         if (offset != offsetof(struct user_regs_struct, gs))
 190                 retval = *pt_regs_access(task_pt_regs(task), offset);
 191         else {
 192                 if (task == current)
 193                         savesegment(gs, retval);
 194                 else
 195                         retval = task->thread.gs;
 196         }
 197         return retval;
 198 }
 199
 200 static int set_segment_reg(struct task_struct *task,
 201                            unsigned long offset, u16 value)
 202 {
 203         if (WARN_ON_ONCE(task == current))
 204                 return -EIO;
 205
 206         /*
 207          * The value argument was already truncated to 16 bits.
 208          */
 209         if (invalid_selector(value))
 210                 return -EIO;
 211
 212         /*
 213          * For %cs and %ss we cannot permit a null selector.
 214          * We can permit a bogus selector as long as it has USER_RPL.
 215          * Null selectors are fine for other segment registers, but
 216          * we will never get back to user mode with invalid %cs or %ss
 217          * and will take the trap in iret instead.  Much code relies
 218          * on user_mode() to distinguish a user trap frame (which can
 219          * safely use invalid selectors) from a kernel trap frame.
 220          */
 221         switch (offset) {
 222         case offsetof(struct user_regs_struct, cs):
 223         case offsetof(struct user_regs_struct, ss):
 224                 if (unlikely(value == 0))
 225                         return -EIO;
 226                 fallthrough;
 227
 228         default:
 229                 *pt_regs_access(task_pt_regs(task), offset) = value;
 230                 break;
 231
 232         case offsetof(struct user_regs_struct, gs):
 233                 task->thread.gs = value;
 234         }
 235
 236         return 0;
 237 }
 238
 239 #else  /* CONFIG_X86_64 */
 240
 241 #define FLAG_MASK               (FLAG_MASK_32 | X86_EFLAGS_NT)
 242
 243 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
 244 {
 245         BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
 246         return &regs->r15 + (offset / sizeof(regs->r15));
 247 }
 248
 249 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
 250 {
 251         /*
 252          * Returning the value truncates it to 16 bits.
 253          */
 254         unsigned int seg;
 255
 256         switch (offset) {
 257         case offsetof(struct user_regs_struct, fs):
 258                 if (task == current) {
 259                         /* Older gas can't assemble movq %?s,%r?? */
 260                         asm("movl %%fs,%0" : "=r" (seg));
 261                         return seg;
 262                 }
 263                 return task->thread.fsindex;
 264         case offsetof(struct user_regs_struct, gs):
 265                 if (task == current) {
 266                         asm("movl %%gs,%0" : "=r" (seg));
 267                         return seg;
 268                 }
 269                 return task->thread.gsindex;
 270         case offsetof(struct user_regs_struct, ds):
 271                 if (task == current) {
 272                         asm("movl %%ds,%0" : "=r" (seg));
 273                         return seg;
 274                 }
 275                 return task->thread.ds;
 276         case offsetof(struct user_regs_struct, es):
 277                 if (task == current) {
 278                         asm("movl %%es,%0" : "=r" (seg));
 279                         return seg;
 280                 }
 281                 return task->thread.es;
 282
 283         case offsetof(struct user_regs_struct, cs):
 284         case offsetof(struct user_regs_struct, ss):
 285                 break;
 286         }
 287         return *pt_regs_access(task_pt_regs(task), offset);
 288 }
 289
 290 static int set_segment_reg(struct task_struct *task,
 291                            unsigned long offset, u16 value)
 292 {
 293         if (WARN_ON_ONCE(task == current))
 294                 return -EIO;
 295
 296         /*
 297          * The value argument was already truncated to 16 bits.
 298          */
 299         if (invalid_selector(value))
 300                 return -EIO;
 301
 302         /*
 303          * Writes to FS and GS will change the stored selector.  Whether
 304          * this changes the segment base as well depends on whether
 305          * FSGSBASE is enabled.
 306          */
 307
 308         switch (offset) {
 309         case offsetof(struct user_regs_struct,fs):
 310                 task->thread.fsindex = value;
 311                 break;
 312         case offsetof(struct user_regs_struct,gs):
 313                 task->thread.gsindex = value;
 314                 break;
 315         case offsetof(struct user_regs_struct,ds):
 316                 task->thread.ds = value;
 317                 break;
 318         case offsetof(struct user_regs_struct,es):
 319                 task->thread.es = value;
 320                 break;
 321
 322                 /*
 323                  * Can't actually change these in 64-bit mode.
 324                  */
 325         case offsetof(struct user_regs_struct,cs):
 326                 if (unlikely(value == 0))
 327                         return -EIO;
 328                 task_pt_regs(task)->cs = value;
 329                 break;
 330         case offsetof(struct user_regs_struct,ss):
 331                 if (unlikely(value == 0))
 332                         return -EIO;
 333                 task_pt_regs(task)->ss = value;
 334                 break;
 335         }
 336
 337         return 0;
 338 }
 339
 340 #endif  /* CONFIG_X86_32 */
 341
 342 static unsigned long get_flags(struct task_struct *task)
 343 {
 344         unsigned long retval = task_pt_regs(task)->flags;
 345
 346         /*
 347          * If the debugger set TF, hide it from the readout.
 348          */
 349         if (test_tsk_thread_flag(task, TIF_FORCED_TF))
 350                 retval &= ~X86_EFLAGS_TF;
 351
 352         return retval;
 353 }
 354
 355 static int set_flags(struct task_struct *task, unsigned long value)
 356 {
 357         struct pt_regs *regs = task_pt_regs(task);
 358
 359         /*
 360          * If the user value contains TF, mark that
 361          * it was not "us" (the debugger) that set it.
 362          * If not, make sure it stays set if we had.
 363          */
 364         if (value & X86_EFLAGS_TF)
 365                 clear_tsk_thread_flag(task, TIF_FORCED_TF);
 366         else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
 367                 value |= X86_EFLAGS_TF;
 368
 369         regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
 370
 371         return 0;
 372 }
 373
 374 static int putreg(struct task_struct *child,
 375                   unsigned long offset, unsigned long value)
 376 {
 377         switch (offset) {
 378         case offsetof(struct user_regs_struct, cs):
 379         case offsetof(struct user_regs_struct, ds):
 380         case offsetof(struct user_regs_struct, es):
 381         case offsetof(struct user_regs_struct, fs):
 382         case offsetof(struct user_regs_struct, gs):
 383         case offsetof(struct user_regs_struct, ss):
 384                 return set_segment_reg(child, offset, value);
 385
 386         case offsetof(struct user_regs_struct, flags):
 387                 return set_flags(child, value);
 388
 389 #ifdef CONFIG_X86_64
 390         case offsetof(struct user_regs_struct,fs_base):
 391                 if (value >= TASK_SIZE_MAX)
 392                         return -EIO;
 393                 x86_fsbase_write_task(child, value);
 394                 return 0;
 395         case offsetof(struct user_regs_struct,gs_base):
 396                 if (value >= TASK_SIZE_MAX)
 397                         return -EIO;
 398                 x86_gsbase_write_task(child, value);
 399                 return 0;
 400 #endif
 401         }
 402
 403         *pt_regs_access(task_pt_regs(child), offset) = value;
 404         return 0;
 405 }
 406
 407 static unsigned long getreg(struct task_struct *task, unsigned long offset)
 408 {
 409         switch (offset) {
 410         case offsetof(struct user_regs_struct, cs):
 411         case offsetof(struct user_regs_struct, ds):
 412         case offsetof(struct user_regs_struct, es):
 413         case offsetof(struct user_regs_struct, fs):
 414         case offsetof(struct user_regs_struct, gs):
 415         case offsetof(struct user_regs_struct, ss):
 416                 return get_segment_reg(task, offset);
 417
 418         case offsetof(struct user_regs_struct, flags):
 419                 return get_flags(task);
 420
 421 #ifdef CONFIG_X86_64
 422         case offsetof(struct user_regs_struct, fs_base):
 423                 return x86_fsbase_read_task(task);
 424         case offsetof(struct user_regs_struct, gs_base):
 425                 return x86_gsbase_read_task(task);
 426 #endif
 427         }
 428
 429         return *pt_regs_access(task_pt_regs(task), offset);
 430 }
 431
 432 static int genregs_get(struct task_struct *target,
 433                        const struct user_regset *regset,
 434                        struct membuf to)
 435 {
 436         int reg;
 437
 438         for (reg = 0; to.left; reg++)
 439                 membuf_store(&to, getreg(target, reg * sizeof(unsigned long)));
 440         return 0;
 441 }
 442
 443 static int genregs_set(struct task_struct *target,
 444                        const struct user_regset *regset,
 445                        unsigned int pos, unsigned int count,
 446                        const void *kbuf, const void __user *ubuf)
 447 {
 448         int ret = 0;
 449         if (kbuf) {
 450                 const unsigned long *k = kbuf;
 451                 while (count >= sizeof(*k) && !ret) {
 452                         ret = putreg(target, pos, *k++);
 453                         count -= sizeof(*k);
 454                         pos += sizeof(*k);
 455                 }
 456         } else {
 457                 const unsigned long  __user *u = ubuf;
 458                 while (count >= sizeof(*u) && !ret) {
 459                         unsigned long word;
 460                         ret = __get_user(word, u++);
 461                         if (ret)
 462                                 break;
 463                         ret = putreg(target, pos, word);
 464                         count -= sizeof(*u);
 465                         pos += sizeof(*u);
 466                 }
 467         }
 468         return ret;
 469 }
 470
 471 static void ptrace_triggered(struct perf_event *bp,
 472                              struct perf_sample_data *data,
 473                              struct pt_regs *regs)
 474 {
 475         int i;
 476         struct thread_struct *thread = &(current->thread);
 477
 478         /*
 479          * Store in the virtual DR6 register the fact that the breakpoint
 480          * was hit so the thread's debugger will see it.
 481          */
 482         for (i = 0; i < HBP_NUM; i++) {
 483                 if (thread->ptrace_bps[i] == bp)
 484                         break;
 485         }
 486
 487         thread->virtual_dr6 |= (DR_TRAP0 << i);
 488 }
 489
 490 /*
 491  * Walk through every ptrace breakpoints for this thread and
 492  * build the dr7 value on top of their attributes.
 493  *
 494  */
 495 static unsigned long ptrace_get_dr7(struct perf_event *bp[])
 496 {
 497         int i;
 498         int dr7 = 0;
 499         struct arch_hw_breakpoint *info;
 500
 501         for (i = 0; i < HBP_NUM; i++) {
 502                 if (bp[i] && !bp[i]->attr.disabled) {
 503                         info = counter_arch_bp(bp[i]);
 504                         dr7 |= encode_dr7(i, info->len, info->type);
 505                 }
 506         }
 507
 508         return dr7;
 509 }
 510
 511 static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
 512                                         int len, int type, bool disabled)
 513 {
 514         int err, bp_len, bp_type;
 515
 516         err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);
 517         if (!err) {
 518                 attr->bp_len = bp_len;
 519                 attr->bp_type = bp_type;
 520                 attr->disabled = disabled;
 521         }
 522
 523         return err;
 524 }
 525
 526 static struct perf_event *
 527 ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,
 528                                 unsigned long addr, bool disabled)
 529 {
 530         struct perf_event_attr attr;
 531         int err;
 532
 533         ptrace_breakpoint_init(&attr);
 534         attr.bp_addr = addr;
 535
 536         err = ptrace_fill_bp_fields(&attr, len, type, disabled);
 537         if (err)
 538                 return ERR_PTR(err);
 539
 540         return register_user_hw_breakpoint(&attr, ptrace_triggered,
 541                                                  NULL, tsk);
 542 }
 543
 544 static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
 545                                         int disabled)
 546 {
 547         struct perf_event_attr attr = bp->attr;
 548         int err;
 549
 550         err = ptrace_fill_bp_fields(&attr, len, type, disabled);
 551         if (err)
 552                 return err;
 553
 554         return modify_user_hw_breakpoint(bp, &attr);
 555 }
 556
 557 /*
 558  * Handle ptrace writes to debug register 7.
 559  */
 560 static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
 561 {
 562         struct thread_struct *thread = &tsk->thread;
 563         unsigned long old_dr7;
 564         bool second_pass = false;
 565         int i, rc, ret = 0;
 566
 567         data &= ~DR_CONTROL_RESERVED;
 568         old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
 569
 570 restore:
 571         rc = 0;
 572         for (i = 0; i < HBP_NUM; i++) {
 573                 unsigned len, type;
 574                 bool disabled = !decode_dr7(data, i, &len, &type);
 575                 struct perf_event *bp = thread->ptrace_bps[i];
 576
 577                 if (!bp) {
 578                         if (disabled)
 579                                 continue;
 580
 581                         bp = ptrace_register_breakpoint(tsk,
 582                                         len, type, 0, disabled);
 583                         if (IS_ERR(bp)) {
 584                                 rc = PTR_ERR(bp);
 585                                 break;
 586                         }
 587
 588                         thread->ptrace_bps[i] = bp;
 589                         continue;
 590                 }
 591
 592                 rc = ptrace_modify_breakpoint(bp, len, type, disabled);
 593                 if (rc)
 594                         break;
 595         }
 596
 597         /* Restore if the first pass failed, second_pass shouldn't fail. */
 598         if (rc && !WARN_ON(second_pass)) {
 599                 ret = rc;
 600                 data = old_dr7;
 601                 second_pass = true;
 602                 goto restore;
 603         }
 604
 605         return ret;
 606 }
 607
 608 /*
 609  * Handle PTRACE_PEEKUSR calls for the debug register area.
 610  */
 611 static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
 612 {
 613         struct thread_struct *thread = &tsk->thread;
 614         unsigned long val = 0;
 615
 616         if (n < HBP_NUM) {
 617                 int index = array_index_nospec(n, HBP_NUM);
 618                 struct perf_event *bp = thread->ptrace_bps[index];
 619
 620                 if (bp)
 621                         val = bp->hw.info.address;
 622         } else if (n == 6) {
 623                 val = thread->virtual_dr6 ^ DR6_RESERVED; /* Flip back to arch polarity */
 624         } else if (n == 7) {
 625                 val = thread->ptrace_dr7;
 626         }
 627         return val;
 628 }
 629
 630 static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
 631                                       unsigned long addr)
 632 {
 633         struct thread_struct *t = &tsk->thread;
 634         struct perf_event *bp = t->ptrace_bps[nr];
 635         int err = 0;
 636
 637         if (!bp) {
 638                 /*
 639                  * Put stub len and type to create an inactive but correct bp.
 640                  *
 641                  * CHECKME: the previous code returned -EIO if the addr wasn't
 642                  * a valid task virtual addr. The new one will return -EINVAL in
 643                  *  this case.
 644                  * -EINVAL may be what we want for in-kernel breakpoints users,
 645                  * but -EIO looks better for ptrace, since we refuse a register
 646                  * writing for the user. And anyway this is the previous
 647                  * behaviour.
 648                  */
 649                 bp = ptrace_register_breakpoint(tsk,
 650                                 X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
 651                                 addr, true);
 652                 if (IS_ERR(bp))
 653                         err = PTR_ERR(bp);
 654                 else
 655                         t->ptrace_bps[nr] = bp;
 656         } else {
 657                 struct perf_event_attr attr = bp->attr;
 658
 659                 attr.bp_addr = addr;
 660                 err = modify_user_hw_breakpoint(bp, &attr);
 661         }
 662
 663         return err;
 664 }
 665
 666 /*
 667  * Handle PTRACE_POKEUSR calls for the debug register area.
 668  */
 669 static int ptrace_set_debugreg(struct task_struct *tsk, int n,
 670                                unsigned long val)
 671 {
 672         struct thread_struct *thread = &tsk->thread;
 673         /* There are no DR4 or DR5 registers */
 674         int rc = -EIO;
 675
 676         if (n < HBP_NUM) {
 677                 rc = ptrace_set_breakpoint_addr(tsk, n, val);
 678         } else if (n == 6) {
 679                 thread->virtual_dr6 = val ^ DR6_RESERVED; /* Flip to positive polarity */
 680                 rc = 0;
 681         } else if (n == 7) {
 682                 rc = ptrace_write_dr7(tsk, val);
 683                 if (!rc)
 684                         thread->ptrace_dr7 = val;
 685         }
 686         return rc;
 687 }
 688
 689 /*
 690  * These access the current or another (stopped) task's io permission
 691  * bitmap for debugging or core dump.
 692  */
 693 static int ioperm_active(struct task_struct *target,
 694                          const struct user_regset *regset)
 695 {
 696         struct io_bitmap *iobm = target->thread.io_bitmap;
 697
 698         return iobm ? DIV_ROUND_UP(iobm->max, regset->size) : 0;
 699 }
 700
 701 static int ioperm_get(struct task_struct *target,
 702                       const struct user_regset *regset,
 703                       struct membuf to)
 704 {
 705         struct io_bitmap *iobm = target->thread.io_bitmap;
 706
 707         if (!iobm)
 708                 return -ENXIO;
 709
 710         return membuf_write(&to, iobm->bitmap, IO_BITMAP_BYTES);
 711 }
 712
 713 /*
 714  * Called by kernel/ptrace.c when detaching..
 715  *
 716  * Make sure the single step bit is not set.
 717  */
 718 void ptrace_disable(struct task_struct *child)
 719 {
 720         user_disable_single_step(child);
 721 }
 722
 723 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 724 static const struct user_regset_view user_x86_32_view; /* Initialized below. */
 725 #endif
 726 #ifdef CONFIG_X86_64
 727 static const struct user_regset_view user_x86_64_view; /* Initialized below. */
 728 #endif
 729
 730 long arch_ptrace(struct task_struct *child, long request,
 731                  unsigned long addr, unsigned long data)
 732 {
 733         int ret;
 734         unsigned long __user *datap = (unsigned long __user *)data;
 735
 736 #ifdef CONFIG_X86_64
 737         /* This is native 64-bit ptrace() */
 738         const struct user_regset_view *regset_view = &user_x86_64_view;
 739 #else
 740         /* This is native 32-bit ptrace() */
 741         const struct user_regset_view *regset_view = &user_x86_32_view;
 742 #endif
 743
 744         switch (request) {
 745         /* read the word at location addr in the USER area. */
 746         case PTRACE_PEEKUSR: {
 747                 unsigned long tmp;
 748
 749                 ret = -EIO;
 750                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
 751                         break;
 752
 753                 tmp = 0;  /* Default return condition */
 754                 if (addr < sizeof(struct user_regs_struct))
 755                         tmp = getreg(child, addr);
 756                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
 757                          addr <= offsetof(struct user, u_debugreg[7])) {
 758                         addr -= offsetof(struct user, u_debugreg[0]);
 759                         tmp = ptrace_get_debugreg(child, addr / sizeof(data));
 760                 }
 761                 ret = put_user(tmp, datap);
 762                 break;
 763         }
 764
 765         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 766                 ret = -EIO;
 767                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
 768                         break;
 769
 770                 if (addr < sizeof(struct user_regs_struct))
 771                         ret = putreg(child, addr, data);
 772                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
 773                          addr <= offsetof(struct user, u_debugreg[7])) {
 774                         addr -= offsetof(struct user, u_debugreg[0]);
 775                         ret = ptrace_set_debugreg(child,
 776                                                   addr / sizeof(data), data);
 777                 }
 778                 break;
 779
 780         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 781                 return copy_regset_to_user(child,
 782                                            regset_view,
 783                                            REGSET_GENERAL,
 784                                            0, sizeof(struct user_regs_struct),
 785                                            datap);
 786
 787         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 788                 return copy_regset_from_user(child,
 789                                              regset_view,
 790                                              REGSET_GENERAL,
 791                                              0, sizeof(struct user_regs_struct),
 792                                              datap);
 793
 794         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 795                 return copy_regset_to_user(child,
 796                                            regset_view,
 797                                            REGSET_FP,
 798                                            0, sizeof(struct user_i387_struct),
 799                                            datap);
 800
 801         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 802                 return copy_regset_from_user(child,
 803                                              regset_view,
 804                                              REGSET_FP,
 805                                              0, sizeof(struct user_i387_struct),
 806                                              datap);
 807
 808 #ifdef CONFIG_X86_32
 809         case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
 810                 return copy_regset_to_user(child, &user_x86_32_view,
 811                                            REGSET32_XFP,
 812                                            0, sizeof(struct user_fxsr_struct),
 813                                            datap) ? -EIO : 0;
 814
 815         case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
 816                 return copy_regset_from_user(child, &user_x86_32_view,
 817                                              REGSET32_XFP,
 818                                              0, sizeof(struct user_fxsr_struct),
 819                                              datap) ? -EIO : 0;
 820 #endif
 821
 822 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 823         case PTRACE_GET_THREAD_AREA:
 824                 if ((int) addr < 0)
 825                         return -EIO;
 826                 ret = do_get_thread_area(child, addr,
 827                                         (struct user_desc __user *)data);
 828                 break;
 829
 830         case PTRACE_SET_THREAD_AREA:
 831                 if ((int) addr < 0)
 832                         return -EIO;
 833                 ret = do_set_thread_area(child, addr,
 834                                         (struct user_desc __user *)data, 0);
 835                 break;
 836 #endif
 837
 838 #ifdef CONFIG_X86_64
 839                 /* normal 64bit interface to access TLS data.
 840                    Works just like arch_prctl, except that the arguments
 841                    are reversed. */
 842         case PTRACE_ARCH_PRCTL:
 843                 ret = do_arch_prctl_64(child, data, addr);
 844                 break;
 845 #endif
 846
 847         default:
 848                 ret = ptrace_request(child, request, addr, data);
 849                 break;
 850         }
 851
 852         return ret;
 853 }
 854
 855 #ifdef CONFIG_IA32_EMULATION
 856
 857 #include <linux/compat.h>
 858 #include <linux/syscalls.h>
 859 #include <asm/ia32.h>
 860 #include <asm/user32.h>
 861
 862 #define R32(l,q)                                                        \
 863         case offsetof(struct user32, regs.l):                           \
 864                 regs->q = value; break
 865
 866 #define SEG32(rs)                                                       \
 867         case offsetof(struct user32, regs.rs):                          \
 868                 return set_segment_reg(child,                           \
 869                                        offsetof(struct user_regs_struct, rs), \
 870                                        value);                          \
 871                 break
 872
 873 static int putreg32(struct task_struct *child, unsigned regno, u32 value)
 874 {
 875         struct pt_regs *regs = task_pt_regs(child);
 876         int ret;
 877
 878         switch (regno) {
 879
 880         SEG32(cs);
 881         SEG32(ds);
 882         SEG32(es);
 883
 884         /*
 885          * A 32-bit ptracer on a 64-bit kernel expects that writing
 886          * FS or GS will also update the base.  This is needed for
 887          * operations like PTRACE_SETREGS to fully restore a saved
 888          * CPU state.
 889          */
 890
 891         case offsetof(struct user32, regs.fs):
 892                 ret = set_segment_reg(child,
 893                                       offsetof(struct user_regs_struct, fs),
 894                                       value);
 895                 if (ret == 0)
 896                         child->thread.fsbase =
 897                                 x86_fsgsbase_read_task(child, value);
 898                 return ret;
 899
 900         case offsetof(struct user32, regs.gs):
 901                 ret = set_segment_reg(child,
 902                                       offsetof(struct user_regs_struct, gs),
 903                                       value);
 904                 if (ret == 0)
 905                         child->thread.gsbase =
 906                                 x86_fsgsbase_read_task(child, value);
 907                 return ret;
 908
 909         SEG32(ss);
 910
 911         R32(ebx, bx);
 912         R32(ecx, cx);
 913         R32(edx, dx);
 914         R32(edi, di);
 915         R32(esi, si);
 916         R32(ebp, bp);
 917         R32(eax, ax);
 918         R32(eip, ip);
 919         R32(esp, sp);
 920
 921         case offsetof(struct user32, regs.orig_eax):
 922                 /*
 923                  * Warning: bizarre corner case fixup here.  A 32-bit
 924                  * debugger setting orig_eax to -1 wants to disable
 925                  * syscall restart.  Make sure that the syscall
 926                  * restart code sign-extends orig_ax.  Also make sure
 927                  * we interpret the -ERESTART* codes correctly if
 928                  * loaded into regs->ax in case the task is not
 929                  * actually still sitting at the exit from a 32-bit
 930                  * syscall with TS_COMPAT still set.
 931                  */
 932                 regs->orig_ax = value;
 933                 if (syscall_get_nr(child, regs) != -1)
 934                         child->thread_info.status |= TS_I386_REGS_POKED;
 935                 break;
 936
 937         case offsetof(struct user32, regs.eflags):
 938                 return set_flags(child, value);
 939
 940         case offsetof(struct user32, u_debugreg[0]) ...
 941                 offsetof(struct user32, u_debugreg[7]):
 942                 regno -= offsetof(struct user32, u_debugreg[0]);
 943                 return ptrace_set_debugreg(child, regno / 4, value);
 944
 945         default:
 946                 if (regno > sizeof(struct user32) || (regno & 3))
 947                         return -EIO;
 948
 949                 /*
 950                  * Other dummy fields in the virtual user structure
 951                  * are ignored
 952                  */
 953                 break;
 954         }
 955         return 0;
 956 }
 957
 958 #undef R32
 959 #undef SEG32
 960
 961 #define R32(l,q)                                                        \
 962         case offsetof(struct user32, regs.l):                           \
 963                 *val = regs->q; break
 964
 965 #define SEG32(rs)                                                       \
 966         case offsetof(struct user32, regs.rs):                          \
 967                 *val = get_segment_reg(child,                           \
 968                                        offsetof(struct user_regs_struct, rs)); \
 969                 break
 970
 971 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
 972 {
 973         struct pt_regs *regs = task_pt_regs(child);
 974
 975         switch (regno) {
 976
 977         SEG32(ds);
 978         SEG32(es);
 979         SEG32(fs);
 980         SEG32(gs);
 981
 982         R32(cs, cs);
 983         R32(ss, ss);
 984         R32(ebx, bx);
 985         R32(ecx, cx);
 986         R32(edx, dx);
 987         R32(edi, di);
 988         R32(esi, si);
 989         R32(ebp, bp);
 990         R32(eax, ax);
 991         R32(orig_eax, orig_ax);
 992         R32(eip, ip);
 993         R32(esp, sp);
 994
 995         case offsetof(struct user32, regs.eflags):
 996                 *val = get_flags(child);
 997                 break;
 998
 999         case offsetof(struct user32, u_debugreg[0]) ...
1000                 offsetof(struct user32, u_debugreg[7]):
1001                 regno -= offsetof(struct user32, u_debugreg[0]);
1002                 *val = ptrace_get_debugreg(child, regno / 4);
1003                 break;
1004
1005         default:
1006                 if (regno > sizeof(struct user32) || (regno & 3))
1007                         return -EIO;
1008
1009                 /*
1010                  * Other dummy fields in the virtual user structure
1011                  * are ignored
1012                  */
1013                 *val = 0;
1014                 break;
1015         }
1016         return 0;
1017 }
1018
1019 #undef R32
1020 #undef SEG32
1021
1022 static int genregs32_get(struct task_struct *target,
1023                          const struct user_regset *regset,
1024                          struct membuf to)
1025 {
1026         int reg;
1027
1028         for (reg = 0; to.left; reg++) {
1029                 u32 val;
1030                 getreg32(target, reg * 4, &val);
1031                 membuf_store(&to, val);
1032         }
1033         return 0;
1034 }
1035
1036 static int genregs32_set(struct task_struct *target,
1037                          const struct user_regset *regset,
1038                          unsigned int pos, unsigned int count,
1039                          const void *kbuf, const void __user *ubuf)
1040 {
1041         int ret = 0;
1042         if (kbuf) {
1043                 const compat_ulong_t *k = kbuf;
1044                 while (count >= sizeof(*k) && !ret) {
1045                         ret = putreg32(target, pos, *k++);
1046                         count -= sizeof(*k);
1047                         pos += sizeof(*k);
1048                 }
1049         } else {
1050                 const compat_ulong_t __user *u = ubuf;
1051                 while (count >= sizeof(*u) && !ret) {
1052                         compat_ulong_t word;
1053                         ret = __get_user(word, u++);
1054                         if (ret)
1055                                 break;
1056                         ret = putreg32(target, pos, word);
1057                         count -= sizeof(*u);
1058                         pos += sizeof(*u);
1059                 }
1060         }
1061         return ret;
1062 }
1063
1064 static long ia32_arch_ptrace(struct task_struct *child, compat_long_t request,
1065                              compat_ulong_t caddr, compat_ulong_t cdata)
1066 {
1067         unsigned long addr = caddr;
1068         unsigned long data = cdata;
1069         void __user *datap = compat_ptr(data);
1070         int ret;
1071         __u32 val;
1072
1073         switch (request) {
1074         case PTRACE_PEEKUSR:
1075                 ret = getreg32(child, addr, &val);
1076                 if (ret == 0)
1077                         ret = put_user(val, (__u32 __user *)datap);
1078                 break;
1079
1080         case PTRACE_POKEUSR:
1081                 ret = putreg32(child, addr, data);
1082                 break;
1083
1084         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
1085                 return copy_regset_to_user(child, &user_x86_32_view,
1086                                            REGSET_GENERAL,
1087                                            0, sizeof(struct user_regs_struct32),
1088                                            datap);
1089
1090         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
1091                 return copy_regset_from_user(child, &user_x86_32_view,
1092                                              REGSET_GENERAL, 0,
1093                                              sizeof(struct user_regs_struct32),
1094                                              datap);
1095
1096         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
1097                 return copy_regset_to_user(child, &user_x86_32_view,
1098                                            REGSET_FP, 0,
1099                                            sizeof(struct user_i387_ia32_struct),
1100                                            datap);
1101
1102         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
1103                 return copy_regset_from_user(
1104                         child, &user_x86_32_view, REGSET_FP,
1105                         0, sizeof(struct user_i387_ia32_struct), datap);
1106
1107         case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
1108                 return copy_regset_to_user(child, &user_x86_32_view,
1109                                            REGSET32_XFP, 0,
1110                                            sizeof(struct user32_fxsr_struct),
1111                                            datap);
1112
1113         case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
1114                 return copy_regset_from_user(child, &user_x86_32_view,
1115                                              REGSET32_XFP, 0,
1116                                              sizeof(struct user32_fxsr_struct),
1117                                              datap);
1118
1119         case PTRACE_GET_THREAD_AREA:
1120         case PTRACE_SET_THREAD_AREA:
1121                 return arch_ptrace(child, request, addr, data);
1122
1123         default:
1124                 return compat_ptrace_request(child, request, addr, data);
1125         }
1126
1127         return ret;
1128 }
1129 #endif /* CONFIG_IA32_EMULATION */
1130
1131 #ifdef CONFIG_X86_X32_ABI
1132 static long x32_arch_ptrace(struct task_struct *child,
1133                             compat_long_t request, compat_ulong_t caddr,
1134                             compat_ulong_t cdata)
1135 {
1136         unsigned long addr = caddr;
1137         unsigned long data = cdata;
1138         void __user *datap = compat_ptr(data);
1139         int ret;
1140
1141         switch (request) {
1142         /* Read 32bits at location addr in the USER area.  Only allow
1143            to return the lower 32bits of segment and debug registers.  */
1144         case PTRACE_PEEKUSR: {
1145                 u32 tmp;
1146
1147                 ret = -EIO;
1148                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1149                     addr < offsetof(struct user_regs_struct, cs))
1150                         break;
1151
1152                 tmp = 0;  /* Default return condition */
1153                 if (addr < sizeof(struct user_regs_struct))
1154                         tmp = getreg(child, addr);
1155                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1156                          addr <= offsetof(struct user, u_debugreg[7])) {
1157                         addr -= offsetof(struct user, u_debugreg[0]);
1158                         tmp = ptrace_get_debugreg(child, addr / sizeof(data));
1159                 }
1160                 ret = put_user(tmp, (__u32 __user *)datap);
1161                 break;
1162         }
1163
1164         /* Write the word at location addr in the USER area.  Only allow
1165            to update segment and debug registers with the upper 32bits
1166            zero-extended. */
1167         case PTRACE_POKEUSR:
1168                 ret = -EIO;
1169                 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1170                     addr < offsetof(struct user_regs_struct, cs))
1171                         break;
1172
1173                 if (addr < sizeof(struct user_regs_struct))
1174                         ret = putreg(child, addr, data);
1175                 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1176                          addr <= offsetof(struct user, u_debugreg[7])) {
1177                         addr -= offsetof(struct user, u_debugreg[0]);
1178                         ret = ptrace_set_debugreg(child,
1179                                                   addr / sizeof(data), data);
1180                 }
1181                 break;
1182
1183         case PTRACE_GETREGS:    /* Get all gp regs from the child. */
1184                 return copy_regset_to_user(child,
1185                                            &user_x86_64_view,
1186                                            REGSET_GENERAL,
1187                                            0, sizeof(struct user_regs_struct),
1188                                            datap);
1189
1190         case PTRACE_SETREGS:    /* Set all gp regs in the child. */
1191                 return copy_regset_from_user(child,
1192                                              &user_x86_64_view,
1193                                              REGSET_GENERAL,
1194                                              0, sizeof(struct user_regs_struct),
1195                                              datap);
1196
1197         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
1198                 return copy_regset_to_user(child,
1199                                            &user_x86_64_view,
1200                                            REGSET_FP,
1201                                            0, sizeof(struct user_i387_struct),
1202                                            datap);
1203
1204         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
1205                 return copy_regset_from_user(child,
1206                                              &user_x86_64_view,
1207                                              REGSET_FP,
1208                                              0, sizeof(struct user_i387_struct),
1209                                              datap);
1210
1211         default:
1212                 return compat_ptrace_request(child, request, addr, data);
1213         }
1214
1215         return ret;
1216 }
1217 #endif
1218
1219 #ifdef CONFIG_COMPAT
1220 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1221                         compat_ulong_t caddr, compat_ulong_t cdata)
1222 {
1223 #ifdef CONFIG_X86_X32_ABI
1224         if (!in_ia32_syscall())
1225                 return x32_arch_ptrace(child, request, caddr, cdata);
1226 #endif
1227 #ifdef CONFIG_IA32_EMULATION
1228         return ia32_arch_ptrace(child, request, caddr, cdata);
1229 #else
1230         return 0;
1231 #endif
1232 }
1233 #endif  /* CONFIG_COMPAT */
1234
1235 #ifdef CONFIG_X86_64
1236
1237 static struct user_regset x86_64_regsets[] __ro_after_init = {
1238         [REGSET64_GENERAL] = {
1239                 .core_note_type = NT_PRSTATUS,
1240                 .n              = sizeof(struct user_regs_struct) / sizeof(long),
1241                 .size           = sizeof(long),
1242                 .align          = sizeof(long),
1243                 .regset_get     = genregs_get,
1244                 .set            = genregs_set
1245         },
1246         [REGSET64_FP] = {
1247                 .core_note_type = NT_PRFPREG,
1248                 .n              = sizeof(struct fxregs_state) / sizeof(long),
1249                 .size           = sizeof(long),
1250                 .align          = sizeof(long),
1251                 .active         = regset_xregset_fpregs_active,
1252                 .regset_get     = xfpregs_get,
1253                 .set            = xfpregs_set
1254         },
1255         [REGSET64_XSTATE] = {
1256                 .core_note_type = NT_X86_XSTATE,
1257                 .size           = sizeof(u64),
1258                 .align          = sizeof(u64),
1259                 .active         = xstateregs_active,
1260                 .regset_get     = xstateregs_get,
1261                 .set            = xstateregs_set
1262         },
1263         [REGSET64_IOPERM] = {
1264                 .core_note_type = NT_386_IOPERM,
1265                 .n              = IO_BITMAP_LONGS,
1266                 .size           = sizeof(long),
1267                 .align          = sizeof(long),
1268                 .active         = ioperm_active,
1269                 .regset_get     = ioperm_get
1270         },
1271 #ifdef CONFIG_X86_USER_SHADOW_STACK
1272         [REGSET64_SSP] = {
1273                 .core_note_type = NT_X86_SHSTK,
1274                 .n              = 1,
1275                 .size           = sizeof(u64),
1276                 .align          = sizeof(u64),
1277                 .active         = ssp_active,
1278                 .regset_get     = ssp_get,
1279                 .set            = ssp_set
1280         },
1281 #endif
1282 };
1283
1284 static const struct user_regset_view user_x86_64_view = {
1285         .name = "x86_64", .e_machine = EM_X86_64,
1286         .regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
1287 };
1288
1289 #else  /* CONFIG_X86_32 */
1290
1291 #define user_regs_struct32      user_regs_struct
1292 #define genregs32_get           genregs_get
1293 #define genregs32_set           genregs_set
1294
1295 #endif  /* CONFIG_X86_64 */
1296
1297 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1298 static struct user_regset x86_32_regsets[] __ro_after_init = {
1299         [REGSET32_GENERAL] = {
1300                 .core_note_type = NT_PRSTATUS,
1301                 .n              = sizeof(struct user_regs_struct32) / sizeof(u32),
1302                 .size           = sizeof(u32),
1303                 .align          = sizeof(u32),
1304                 .regset_get     = genregs32_get,
1305                 .set            = genregs32_set
1306         },
1307         [REGSET32_FP] = {
1308                 .core_note_type = NT_PRFPREG,
1309                 .n              = sizeof(struct user_i387_ia32_struct) / sizeof(u32),
1310                 .size           = sizeof(u32),
1311                 .align          = sizeof(u32),
1312                 .active         = regset_fpregs_active,
1313                 .regset_get     = fpregs_get,
1314                 .set            = fpregs_set
1315         },
1316         [REGSET32_XFP] = {
1317                 .core_note_type = NT_PRXFPREG,
1318                 .n              = sizeof(struct fxregs_state) / sizeof(u32),
1319                 .size           = sizeof(u32),
1320                 .align          = sizeof(u32),
1321                 .active         = regset_xregset_fpregs_active,
1322                 .regset_get     = xfpregs_get,
1323                 .set            = xfpregs_set
1324         },
1325         [REGSET32_XSTATE] = {
1326                 .core_note_type = NT_X86_XSTATE,
1327                 .size           = sizeof(u64),
1328                 .align          = sizeof(u64),
1329                 .active         = xstateregs_active,
1330                 .regset_get     = xstateregs_get,
1331                 .set            = xstateregs_set
1332         },
1333         [REGSET32_TLS] = {
1334                 .core_note_type = NT_386_TLS,
1335                 .n              = GDT_ENTRY_TLS_ENTRIES,
1336                 .bias           = GDT_ENTRY_TLS_MIN,
1337                 .size           = sizeof(struct user_desc),
1338                 .align          = sizeof(struct user_desc),
1339                 .active         = regset_tls_active,
1340                 .regset_get     = regset_tls_get,
1341                 .set            = regset_tls_set
1342         },
1343         [REGSET32_IOPERM] = {
1344                 .core_note_type = NT_386_IOPERM,
1345                 .n              = IO_BITMAP_BYTES / sizeof(u32),
1346                 .size           = sizeof(u32),
1347                 .align          = sizeof(u32),
1348                 .active         = ioperm_active,
1349                 .regset_get     = ioperm_get
1350         },
1351 };
1352
1353 static const struct user_regset_view user_x86_32_view = {
1354         .name = "i386", .e_machine = EM_386,
1355         .regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
1356 };
1357 #endif
1358
1359 /*
1360  * This represents bytes 464..511 in the memory layout exported through
1361  * the REGSET_XSTATE interface.
1362  */
1363 u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
1364
1365 void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask)
1366 {
1367 #ifdef CONFIG_X86_64
1368         x86_64_regsets[REGSET64_XSTATE].n = size / sizeof(u64);
1369 #endif
1370 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1371         x86_32_regsets[REGSET32_XSTATE].n = size / sizeof(u64);
1372 #endif
1373         xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
1374 }
1375
1376 /*
1377  * This is used by the core dump code to decide which regset to dump.  The
1378  * core dump code writes out the resulting .e_machine and the corresponding
1379  * regsets.  This is suboptimal if the task is messing around with its CS.L
1380  * field, but at worst the core dump will end up missing some information.
1381  *
1382  * Unfortunately, it is also used by the broken PTRACE_GETREGSET and
1383  * PTRACE_SETREGSET APIs.  These APIs look at the .regsets field but have
1384  * no way to make sure that the e_machine they use matches the caller's
1385  * expectations.  The result is that the data format returned by
1386  * PTRACE_GETREGSET depends on the returned CS field (and even the offset
1387  * of the returned CS field depends on its value!) and the data format
1388  * accepted by PTRACE_SETREGSET is determined by the old CS value.  The
1389  * upshot is that it is basically impossible to use these APIs correctly.
1390  *
1391  * The best way to fix it in the long run would probably be to add new
1392  * improved ptrace() APIs to read and write registers reliably, possibly by
1393  * allowing userspace to select the ELF e_machine variant that they expect.
1394  */
1395 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1396 {
1397 #ifdef CONFIG_IA32_EMULATION
1398         if (!user_64bit_mode(task_pt_regs(task)))
1399 #endif
1400 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1401                 return &user_x86_32_view;
1402 #endif
1403 #ifdef CONFIG_X86_64
1404         return &user_x86_64_view;
1405 #endif
1406 }
1407
1408 void send_sigtrap(struct pt_regs *regs, int error_code, int si_code)
1409 {
1410         struct task_struct *tsk = current;
1411
1412         tsk->thread.trap_nr = X86_TRAP_DB;
1413         tsk->thread.error_code = error_code;
1414
1415         /* Send us the fake SIGTRAP */
1416         force_sig_fault(SIGTRAP, si_code,
1417                         user_mode(regs) ? (void __user *)regs->ip : NULL);
1418 }
1419
1420 void user_single_step_report(struct pt_regs *regs)
1421 {
1422         send_sigtrap(regs, 0, TRAP_BRKPT);
1423 }