arch/x86/kernel/signal.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
   4  *
   5  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   6  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   7  *  2000-2002   x86-64 support by Andi Kleen
   8  */
   9 #include <linux/sched.h>
  10 #include <linux/mm.h>
  11 #include <linux/smp.h>
  12 #include <linux/kernel.h>
  13 #include <linux/signal.h>
  14 #include <linux/errno.h>
  15 #include <linux/wait.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/tracehook.h>
  18 #include <linux/unistd.h>
  19 #include <linux/stddef.h>
  20 #include <linux/personality.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/user-return-notifier.h>
  23
  24 #include <asm/processor.h>
  25 #include <asm/ucontext.h>
  26 #include <asm/i387.h>
  27 #include <asm/vdso.h>
  28 #include <asm/mce.h>
  29
  30 #ifdef CONFIG_X86_64
  31 #include <asm/proto.h>
  32 #include <asm/ia32_unistd.h>
  33 #endif /* CONFIG_X86_64 */
  34
  35 #include <asm/syscall.h>
  36 #include <asm/syscalls.h>
  37
  38 #include <asm/sigframe.h>
  39
  40 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  41
  42 #define __FIX_EFLAGS    (X86_EFLAGS_AC | X86_EFLAGS_OF | \
  43                          X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
  44                          X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
  45                          X86_EFLAGS_CF)
  46
  47 #ifdef CONFIG_X86_32
  48 # define FIX_EFLAGS     (__FIX_EFLAGS | X86_EFLAGS_RF)
  49 #else
  50 # define FIX_EFLAGS     __FIX_EFLAGS
  51 #endif
  52
  53 #define COPY(x)                 do {                    \
  54         get_user_ex(regs->x, &sc->x);                   \
  55 } while (0)
  56
  57 #define GET_SEG(seg)            ({                      \
  58         unsigned short tmp;                             \
  59         get_user_ex(tmp, &sc->seg);                     \
  60         tmp;                                            \
  61 })
  62
  63 #define COPY_SEG(seg)           do {                    \
  64         regs->seg = GET_SEG(seg);                       \
  65 } while (0)
  66
  67 #define COPY_SEG_CPL3(seg)      do {                    \
  68         regs->seg = GET_SEG(seg) | 3;                   \
  69 } while (0)
  70
  71 static int
  72 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  73                    unsigned long *pax)
  74 {
  75         void __user *buf;
  76         unsigned int tmpflags;
  77         unsigned int err = 0;
  78
  79         /* Always make any pending restarted system calls return -EINTR */
  80         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  81
  82         get_user_try {
  83
  84 #ifdef CONFIG_X86_32
  85                 set_user_gs(regs, GET_SEG(gs));
  86                 COPY_SEG(fs);
  87                 COPY_SEG(es);
  88                 COPY_SEG(ds);
  89 #endif /* CONFIG_X86_32 */
  90
  91                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  92                 COPY(dx); COPY(cx); COPY(ip);
  93
  94 #ifdef CONFIG_X86_64
  95                 COPY(r8);
  96                 COPY(r9);
  97                 COPY(r10);
  98                 COPY(r11);
  99                 COPY(r12);
 100                 COPY(r13);
 101                 COPY(r14);
 102                 COPY(r15);
 103 #endif /* CONFIG_X86_64 */
 104
 105 #ifdef CONFIG_X86_32
 106                 COPY_SEG_CPL3(cs);
 107                 COPY_SEG_CPL3(ss);
 108 #else /* !CONFIG_X86_32 */
 109                 /* Kernel saves and restores only the CS segment register on signals,
 110                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 111                  * App's signal handler can save/restore other segments if needed. */
 112                 COPY_SEG_CPL3(cs);
 113 #endif /* CONFIG_X86_32 */
 114
 115                 get_user_ex(tmpflags, &sc->flags);
 116                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 117                 regs->orig_ax = -1;             /* disable syscall checks */
 118
 119                 get_user_ex(buf, &sc->fpstate);
 120                 err |= restore_i387_xstate(buf);
 121
 122                 get_user_ex(*pax, &sc->ax);
 123         } get_user_catch(err);
 124
 125         return err;
 126 }
 127
 128 static int
 129 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 130                  struct pt_regs *regs, unsigned long mask)
 131 {
 132         int err = 0;
 133
 134         put_user_try {
 135
 136 #ifdef CONFIG_X86_32
 137                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 138                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 139                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 140                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 141 #endif /* CONFIG_X86_32 */
 142
 143                 put_user_ex(regs->di, &sc->di);
 144                 put_user_ex(regs->si, &sc->si);
 145                 put_user_ex(regs->bp, &sc->bp);
 146                 put_user_ex(regs->sp, &sc->sp);
 147                 put_user_ex(regs->bx, &sc->bx);
 148                 put_user_ex(regs->dx, &sc->dx);
 149                 put_user_ex(regs->cx, &sc->cx);
 150                 put_user_ex(regs->ax, &sc->ax);
 151 #ifdef CONFIG_X86_64
 152                 put_user_ex(regs->r8, &sc->r8);
 153                 put_user_ex(regs->r9, &sc->r9);
 154                 put_user_ex(regs->r10, &sc->r10);
 155                 put_user_ex(regs->r11, &sc->r11);
 156                 put_user_ex(regs->r12, &sc->r12);
 157                 put_user_ex(regs->r13, &sc->r13);
 158                 put_user_ex(regs->r14, &sc->r14);
 159                 put_user_ex(regs->r15, &sc->r15);
 160 #endif /* CONFIG_X86_64 */
 161
 162                 put_user_ex(current->thread.trap_no, &sc->trapno);
 163                 put_user_ex(current->thread.error_code, &sc->err);
 164                 put_user_ex(regs->ip, &sc->ip);
 165 #ifdef CONFIG_X86_32
 166                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 167                 put_user_ex(regs->flags, &sc->flags);
 168                 put_user_ex(regs->sp, &sc->sp_at_signal);
 169                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 170 #else /* !CONFIG_X86_32 */
 171                 put_user_ex(regs->flags, &sc->flags);
 172                 put_user_ex(regs->cs, &sc->cs);
 173                 put_user_ex(0, &sc->gs);
 174                 put_user_ex(0, &sc->fs);
 175 #endif /* CONFIG_X86_32 */
 176
 177                 put_user_ex(fpstate, &sc->fpstate);
 178
 179                 /* non-iBCS2 extensions.. */
 180                 put_user_ex(mask, &sc->oldmask);
 181                 put_user_ex(current->thread.cr2, &sc->cr2);
 182         } put_user_catch(err);
 183
 184         return err;
 185 }
 186
 187 /*
 188  * Set up a signal frame.
 189  */
 190
 191 /*
 192  * Determine which stack to use..
 193  */
 194 static unsigned long align_sigframe(unsigned long sp)
 195 {
 196 #ifdef CONFIG_X86_32
 197         /*
 198          * Align the stack pointer according to the i386 ABI,
 199          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 200          */
 201         sp = ((sp + 4) & -16ul) - 4;
 202 #else /* !CONFIG_X86_32 */
 203         sp = round_down(sp, 16) - 8;
 204 #endif
 205         return sp;
 206 }
 207
 208 static inline void __user *
 209 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 210              void __user **fpstate)
 211 {
 212         /* Default to using normal stack */
 213         unsigned long sp = regs->sp;
 214         int onsigstack = on_sig_stack(sp);
 215
 216 #ifdef CONFIG_X86_64
 217         /* redzone */
 218         sp -= 128;
 219 #endif /* CONFIG_X86_64 */
 220
 221         if (!onsigstack) {
 222                 /* This is the X/Open sanctioned signal stack switching.  */
 223                 if (ka->sa.sa_flags & SA_ONSTACK) {
 224                         if (current->sas_ss_size)
 225                                 sp = current->sas_ss_sp + current->sas_ss_size;
 226                 } else {
 227 #ifdef CONFIG_X86_32
 228                         /* This is the legacy signal stack switching. */
 229                         if ((regs->ss & 0xffff) != __USER_DS &&
 230                                 !(ka->sa.sa_flags & SA_RESTORER) &&
 231                                         ka->sa.sa_restorer)
 232                                 sp = (unsigned long) ka->sa.sa_restorer;
 233 #endif /* CONFIG_X86_32 */
 234                 }
 235         }
 236
 237         if (used_math()) {
 238                 sp -= sig_xstate_size;
 239 #ifdef CONFIG_X86_64
 240                 sp = round_down(sp, 64);
 241 #endif /* CONFIG_X86_64 */
 242                 *fpstate = (void __user *)sp;
 243         }
 244
 245         sp = align_sigframe(sp - frame_size);
 246
 247         /*
 248          * If we are on the alternate signal stack and would overflow it, don't.
 249          * Return an always-bogus address instead so we will die with SIGSEGV.
 250          */
 251         if (onsigstack && !likely(on_sig_stack(sp)))
 252                 return (void __user *)-1L;
 253
 254         /* save i387 state */
 255         if (used_math() && save_i387_xstate(*fpstate) < 0)
 256                 return (void __user *)-1L;
 257
 258         return (void __user *)sp;
 259 }
 260
 261 #ifdef CONFIG_X86_32
 262 static const struct {
 263         u16 poplmovl;
 264         u32 val;
 265         u16 int80;
 266 } __attribute__((packed)) retcode = {
 267         0xb858,         /* popl %eax; movl $..., %eax */
 268         __NR_sigreturn,
 269         0x80cd,         /* int $0x80 */
 270 };
 271
 272 static const struct {
 273         u8  movl;
 274         u32 val;
 275         u16 int80;
 276         u8  pad;
 277 } __attribute__((packed)) rt_retcode = {
 278         0xb8,           /* movl $..., %eax */
 279         __NR_rt_sigreturn,
 280         0x80cd,         /* int $0x80 */
 281         0
 282 };
 283
 284 static int
 285 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 286               struct pt_regs *regs)
 287 {
 288         struct sigframe __user *frame;
 289         void __user *restorer;
 290         int err = 0;
 291         void __user *fpstate = NULL;
 292
 293         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 294
 295         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 296                 return -EFAULT;
 297
 298         if (__put_user(sig, &frame->sig))
 299                 return -EFAULT;
 300
 301         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 302                 return -EFAULT;
 303
 304         if (_NSIG_WORDS > 1) {
 305                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 306                                    sizeof(frame->extramask)))
 307                         return -EFAULT;
 308         }
 309
 310         if (current->mm->context.vdso)
 311                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 312         else
 313                 restorer = &frame->retcode;
 314         if (ka->sa.sa_flags & SA_RESTORER)
 315                 restorer = ka->sa.sa_restorer;
 316
 317         /* Set up to return from userspace.  */
 318         err |= __put_user(restorer, &frame->pretcode);
 319
 320         /*
 321          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 322          *
 323          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 324          * reasons and because gdb uses it as a signature to notice
 325          * signal handler stack frames.
 326          */
 327         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 328
 329         if (err)
 330                 return -EFAULT;
 331
 332         /* Set up registers for signal handler */
 333         regs->sp = (unsigned long)frame;
 334         regs->ip = (unsigned long)ka->sa.sa_handler;
 335         regs->ax = (unsigned long)sig;
 336         regs->dx = 0;
 337         regs->cx = 0;
 338
 339         regs->ds = __USER_DS;
 340         regs->es = __USER_DS;
 341         regs->ss = __USER_DS;
 342         regs->cs = __USER_CS;
 343
 344         return 0;
 345 }
 346
 347 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 348                             sigset_t *set, struct pt_regs *regs)
 349 {
 350         struct rt_sigframe __user *frame;
 351         void __user *restorer;
 352         int err = 0;
 353         void __user *fpstate = NULL;
 354
 355         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 356
 357         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 358                 return -EFAULT;
 359
 360         put_user_try {
 361                 put_user_ex(sig, &frame->sig);
 362                 put_user_ex(&frame->info, &frame->pinfo);
 363                 put_user_ex(&frame->uc, &frame->puc);
 364                 err |= copy_siginfo_to_user(&frame->info, info);
 365
 366                 /* Create the ucontext.  */
 367                 if (cpu_has_xsave)
 368                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 369                 else
 370                         put_user_ex(0, &frame->uc.uc_flags);
 371                 put_user_ex(0, &frame->uc.uc_link);
 372                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 373                 put_user_ex(sas_ss_flags(regs->sp),
 374                             &frame->uc.uc_stack.ss_flags);
 375                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 376                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 377                                         regs, set->sig[0]);
 378                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 379
 380                 /* Set up to return from userspace.  */
 381                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 382                 if (ka->sa.sa_flags & SA_RESTORER)
 383                         restorer = ka->sa.sa_restorer;
 384                 put_user_ex(restorer, &frame->pretcode);
 385
 386                 /*
 387                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 388                  *
 389                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 390                  * reasons and because gdb uses it as a signature to notice
 391                  * signal handler stack frames.
 392                  */
 393                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 394         } put_user_catch(err);
 395
 396         if (err)
 397                 return -EFAULT;
 398
 399         /* Set up registers for signal handler */
 400         regs->sp = (unsigned long)frame;
 401         regs->ip = (unsigned long)ka->sa.sa_handler;
 402         regs->ax = (unsigned long)sig;
 403         regs->dx = (unsigned long)&frame->info;
 404         regs->cx = (unsigned long)&frame->uc;
 405
 406         regs->ds = __USER_DS;
 407         regs->es = __USER_DS;
 408         regs->ss = __USER_DS;
 409         regs->cs = __USER_CS;
 410
 411         return 0;
 412 }
 413 #else /* !CONFIG_X86_32 */
 414 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 415                             sigset_t *set, struct pt_regs *regs)
 416 {
 417         struct rt_sigframe __user *frame;
 418         void __user *fp = NULL;
 419         int err = 0;
 420         struct task_struct *me = current;
 421
 422         frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
 423
 424         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 425                 return -EFAULT;
 426
 427         if (ka->sa.sa_flags & SA_SIGINFO) {
 428                 if (copy_siginfo_to_user(&frame->info, info))
 429                         return -EFAULT;
 430         }
 431
 432         put_user_try {
 433                 /* Create the ucontext.  */
 434                 if (cpu_has_xsave)
 435                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 436                 else
 437                         put_user_ex(0, &frame->uc.uc_flags);
 438                 put_user_ex(0, &frame->uc.uc_link);
 439                 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 440                 put_user_ex(sas_ss_flags(regs->sp),
 441                             &frame->uc.uc_stack.ss_flags);
 442                 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 443                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 444                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 445
 446                 /* Set up to return from userspace.  If provided, use a stub
 447                    already in userspace.  */
 448                 /* x86-64 should always use SA_RESTORER. */
 449                 if (ka->sa.sa_flags & SA_RESTORER) {
 450                         put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 451                 } else {
 452                         /* could use a vstub here */
 453                         err |= -EFAULT;
 454                 }
 455         } put_user_catch(err);
 456
 457         if (err)
 458                 return -EFAULT;
 459
 460         /* Set up registers for signal handler */
 461         regs->di = sig;
 462         /* In case the signal handler was declared without prototypes */
 463         regs->ax = 0;
 464
 465         /* This also works for non SA_SIGINFO handlers because they expect the
 466            next argument after the signal number on the stack. */
 467         regs->si = (unsigned long)&frame->info;
 468         regs->dx = (unsigned long)&frame->uc;
 469         regs->ip = (unsigned long) ka->sa.sa_handler;
 470
 471         regs->sp = (unsigned long)frame;
 472
 473         /* Set up the CS register to run signal handlers in 64-bit mode,
 474            even if the handler happens to be interrupting 32-bit code. */
 475         regs->cs = __USER_CS;
 476
 477         return 0;
 478 }
 479 #endif /* CONFIG_X86_32 */
 480
 481 #ifdef CONFIG_X86_32
 482 /*
 483  * Atomically swap in the new signal mask, and wait for a signal.
 484  */
 485 asmlinkage int
 486 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 487 {
 488         mask &= _BLOCKABLE;
 489         spin_lock_irq(&current->sighand->siglock);
 490         current->saved_sigmask = current->blocked;
 491         siginitset(&current->blocked, mask);
 492         recalc_sigpending();
 493         spin_unlock_irq(&current->sighand->siglock);
 494
 495         current->state = TASK_INTERRUPTIBLE;
 496         schedule();
 497         set_restore_sigmask();
 498
 499         return -ERESTARTNOHAND;
 500 }
 501
 502 asmlinkage int
 503 sys_sigaction(int sig, const struct old_sigaction __user *act,
 504               struct old_sigaction __user *oact)
 505 {
 506         struct k_sigaction new_ka, old_ka;
 507         int ret = 0;
 508
 509         if (act) {
 510                 old_sigset_t mask;
 511
 512                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 513                         return -EFAULT;
 514
 515                 get_user_try {
 516                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 517                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 518                         get_user_ex(mask, &act->sa_mask);
 519                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 520                 } get_user_catch(ret);
 521
 522                 if (ret)
 523                         return -EFAULT;
 524                 siginitset(&new_ka.sa.sa_mask, mask);
 525         }
 526
 527         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 528
 529         if (!ret && oact) {
 530                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 531                         return -EFAULT;
 532
 533                 put_user_try {
 534                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 535                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 536                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 537                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 538                 } put_user_catch(ret);
 539
 540                 if (ret)
 541                         return -EFAULT;
 542         }
 543
 544         return ret;
 545 }
 546 #endif /* CONFIG_X86_32 */
 547
 548 long
 549 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 550                 struct pt_regs *regs)
 551 {
 552         return do_sigaltstack(uss, uoss, regs->sp);
 553 }
 554
 555 /*
 556  * Do a signal return; undo the signal stack.
 557  */
 558 #ifdef CONFIG_X86_32
 559 unsigned long sys_sigreturn(struct pt_regs *regs)
 560 {
 561         struct sigframe __user *frame;
 562         unsigned long ax;
 563         sigset_t set;
 564
 565         frame = (struct sigframe __user *)(regs->sp - 8);
 566
 567         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 568                 goto badframe;
 569         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 570                 && __copy_from_user(&set.sig[1], &frame->extramask,
 571                                     sizeof(frame->extramask))))
 572                 goto badframe;
 573
 574         sigdelsetmask(&set, ~_BLOCKABLE);
 575         spin_lock_irq(&current->sighand->siglock);
 576         current->blocked = set;
 577         recalc_sigpending();
 578         spin_unlock_irq(&current->sighand->siglock);
 579
 580         if (restore_sigcontext(regs, &frame->sc, &ax))
 581                 goto badframe;
 582         return ax;
 583
 584 badframe:
 585         signal_fault(regs, frame, "sigreturn");
 586
 587         return 0;
 588 }
 589 #endif /* CONFIG_X86_32 */
 590
 591 long sys_rt_sigreturn(struct pt_regs *regs)
 592 {
 593         struct rt_sigframe __user *frame;
 594         unsigned long ax;
 595         sigset_t set;
 596
 597         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 598         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 599                 goto badframe;
 600         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 601                 goto badframe;
 602
 603         sigdelsetmask(&set, ~_BLOCKABLE);
 604         spin_lock_irq(&current->sighand->siglock);
 605         current->blocked = set;
 606         recalc_sigpending();
 607         spin_unlock_irq(&current->sighand->siglock);
 608
 609         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 610                 goto badframe;
 611
 612         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 613                 goto badframe;
 614
 615         return ax;
 616
 617 badframe:
 618         signal_fault(regs, frame, "rt_sigreturn");
 619         return 0;
 620 }
 621
 622 /*
 623  * OK, we're invoking a handler:
 624  */
 625 static int signr_convert(int sig)
 626 {
 627 #ifdef CONFIG_X86_32
 628         struct thread_info *info = current_thread_info();
 629
 630         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 631                 return info->exec_domain->signal_invmap[sig];
 632 #endif /* CONFIG_X86_32 */
 633         return sig;
 634 }
 635
 636 #ifdef CONFIG_X86_32
 637
 638 #define is_ia32 1
 639 #define ia32_setup_frame        __setup_frame
 640 #define ia32_setup_rt_frame     __setup_rt_frame
 641
 642 #else /* !CONFIG_X86_32 */
 643
 644 #ifdef CONFIG_IA32_EMULATION
 645 #define is_ia32 test_thread_flag(TIF_IA32)
 646 #else /* !CONFIG_IA32_EMULATION */
 647 #define is_ia32 0
 648 #endif /* CONFIG_IA32_EMULATION */
 649
 650 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 651                 sigset_t *set, struct pt_regs *regs);
 652 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 653                 sigset_t *set, struct pt_regs *regs);
 654
 655 #endif /* CONFIG_X86_32 */
 656
 657 static int
 658 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 659                sigset_t *set, struct pt_regs *regs)
 660 {
 661         int usig = signr_convert(sig);
 662         int ret;
 663
 664         /* Set up the stack frame */
 665         if (is_ia32) {
 666                 if (ka->sa.sa_flags & SA_SIGINFO)
 667                         ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
 668                 else
 669                         ret = ia32_setup_frame(usig, ka, set, regs);
 670         } else
 671                 ret = __setup_rt_frame(sig, ka, info, set, regs);
 672
 673         if (ret) {
 674                 force_sigsegv(sig, current);
 675                 return -EFAULT;
 676         }
 677
 678         return ret;
 679 }
 680
 681 static int
 682 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 683               sigset_t *oldset, struct pt_regs *regs)
 684 {
 685         int ret;
 686
 687         /* Are we from a system call? */
 688         if (syscall_get_nr(current, regs) >= 0) {
 689                 /* If so, check system call restarting.. */
 690                 switch (syscall_get_error(current, regs)) {
 691                 case -ERESTART_RESTARTBLOCK:
 692                 case -ERESTARTNOHAND:
 693                         regs->ax = -EINTR;
 694                         break;
 695
 696                 case -ERESTARTSYS:
 697                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 698                                 regs->ax = -EINTR;
 699                                 break;
 700                         }
 701                 /* fallthrough */
 702                 case -ERESTARTNOINTR:
 703                         regs->ax = regs->orig_ax;
 704                         regs->ip -= 2;
 705                         break;
 706                 }
 707         }
 708
 709         /*
 710          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 711          * flag so that register information in the sigcontext is correct.
 712          */
 713         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 714             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 715                 regs->flags &= ~X86_EFLAGS_TF;
 716
 717         ret = setup_rt_frame(sig, ka, info, oldset, regs);
 718
 719         if (ret)
 720                 return ret;
 721
 722 #ifdef CONFIG_X86_64
 723         /*
 724          * This has nothing to do with segment registers,
 725          * despite the name.  This magic affects uaccess.h
 726          * macros' behavior.  Reset it to the normal setting.
 727          */
 728         set_fs(USER_DS);
 729 #endif
 730
 731         /*
 732          * Clear the direction flag as per the ABI for function entry.
 733          */
 734         regs->flags &= ~X86_EFLAGS_DF;
 735
 736         /*
 737          * Clear TF when entering the signal handler, but
 738          * notify any tracer that was single-stepping it.
 739          * The tracer may want to single-step inside the
 740          * handler too.
 741          */
 742         regs->flags &= ~X86_EFLAGS_TF;
 743
 744         spin_lock_irq(&current->sighand->siglock);
 745         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 746         if (!(ka->sa.sa_flags & SA_NODEFER))
 747                 sigaddset(&current->blocked, sig);
 748         recalc_sigpending();
 749         spin_unlock_irq(&current->sighand->siglock);
 750
 751         tracehook_signal_handler(sig, info, ka, regs,
 752                                  test_thread_flag(TIF_SINGLESTEP));
 753
 754         return 0;
 755 }
 756
 757 #ifdef CONFIG_X86_32
 758 #define NR_restart_syscall      __NR_restart_syscall
 759 #else /* !CONFIG_X86_32 */
 760 #define NR_restart_syscall      \
 761         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 762 #endif /* CONFIG_X86_32 */
 763
 764 /*
 765  * Note that 'init' is a special process: it doesn't get signals it doesn't
 766  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 767  * mistake.
 768  */
 769 static void do_signal(struct pt_regs *regs)
 770 {
 771         struct k_sigaction ka;
 772         siginfo_t info;
 773         int signr;
 774         sigset_t *oldset;
 775
 776         /*
 777          * We want the common case to go fast, which is why we may in certain
 778          * cases get here from kernel mode. Just return without doing anything
 779          * if so.
 780          * X86_32: vm86 regs switched out by assembly code before reaching
 781          * here, so testing against kernel CS suffices.
 782          */
 783         if (!user_mode(regs))
 784                 return;
 785
 786         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 787                 oldset = &current->saved_sigmask;
 788         else
 789                 oldset = &current->blocked;
 790
 791         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 792         if (signr > 0) {
 793                 /* Whee! Actually deliver the signal.  */
 794                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 795                         /*
 796                          * A signal was successfully delivered; the saved
 797                          * sigmask will have been stored in the signal frame,
 798                          * and will be restored by sigreturn, so we can simply
 799                          * clear the TS_RESTORE_SIGMASK flag.
 800                          */
 801                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 802                 }
 803                 return;
 804         }
 805
 806         /* Did we come from a system call? */
 807         if (syscall_get_nr(current, regs) >= 0) {
 808                 /* Restart the system call - no handlers present */
 809                 switch (syscall_get_error(current, regs)) {
 810                 case -ERESTARTNOHAND:
 811                 case -ERESTARTSYS:
 812                 case -ERESTARTNOINTR:
 813                         regs->ax = regs->orig_ax;
 814                         regs->ip -= 2;
 815                         break;
 816
 817                 case -ERESTART_RESTARTBLOCK:
 818                         regs->ax = NR_restart_syscall;
 819                         regs->ip -= 2;
 820                         break;
 821                 }
 822         }
 823
 824         /*
 825          * If there's no signal to deliver, we just put the saved sigmask
 826          * back.
 827          */
 828         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 829                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 830                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 831         }
 832 }
 833
 834 /*
 835  * notification of userspace execution resumption
 836  * - triggered by the TIF_WORK_MASK flags
 837  */
 838 void
 839 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 840 {
 841 #ifdef CONFIG_X86_MCE
 842         /* notify userspace of pending MCEs */
 843         if (thread_info_flags & _TIF_MCE_NOTIFY)
 844                 mce_notify_process();
 845 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 846
 847         /* deal with pending signal delivery */
 848         if (thread_info_flags & _TIF_SIGPENDING)
 849                 do_signal(regs);
 850
 851         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 852                 clear_thread_flag(TIF_NOTIFY_RESUME);
 853                 tracehook_notify_resume(regs);
 854                 if (current->replacement_session_keyring)
 855                         key_replace_session_keyring();
 856         }
 857         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 858                 fire_user_return_notifiers();
 859
 860 #ifdef CONFIG_X86_32
 861         clear_thread_flag(TIF_IRET);
 862 #endif /* CONFIG_X86_32 */
 863 }
 864
 865 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 866 {
 867         struct task_struct *me = current;
 868
 869         if (show_unhandled_signals && printk_ratelimit()) {
 870                 printk("%s"
 871                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 872                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 873                        me->comm, me->pid, where, frame,
 874                        regs->ip, regs->sp, regs->orig_ax);
 875                 print_vma_addr(" in ", regs->ip);
 876                 printk(KERN_CONT "\n");
 877         }
 878
 879         force_sig(SIGSEGV, me);
 880 }