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
  10 #include <linux/sched.h>
  11 #include <linux/mm.h>
  12 #include <linux/smp.h>
  13 #include <linux/kernel.h>
  14 #include <linux/signal.h>
  15 #include <linux/errno.h>
  16 #include <linux/wait.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/tracehook.h>
  19 #include <linux/unistd.h>
  20 #include <linux/stddef.h>
  21 #include <linux/personality.h>
  22 #include <linux/uaccess.h>
  23
  24 #include <asm/processor.h>
  25 #include <asm/ucontext.h>
  26 #include <asm/i387.h>
  27 #include <asm/vdso.h>
  28
  29 #ifdef CONFIG_X86_64
  30 #include <asm/proto.h>
  31 #include <asm/ia32_unistd.h>
  32 #include <asm/mce.h>
  33 #endif /* CONFIG_X86_64 */
  34
  35 #include <asm/syscall.h>
  36 #include <asm/syscalls.h>
  37
  38 #include "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)                 {               \
  54         err |= __get_user(regs->x, &sc->x);     \
  55 }
  56
  57 #define COPY_SEG(seg)           {                       \
  58                 unsigned short tmp;                     \
  59                 err |= __get_user(tmp, &sc->seg);       \
  60                 regs->seg = tmp;                        \
  61 }
  62
  63 #define COPY_SEG_CPL3(seg)      {                       \
  64                 unsigned short tmp;                     \
  65                 err |= __get_user(tmp, &sc->seg);       \
  66                 regs->seg = tmp | 3;                    \
  67 }
  68
  69 #define GET_SEG(seg)            {                       \
  70                 unsigned short tmp;                     \
  71                 err |= __get_user(tmp, &sc->seg);       \
  72                 loadsegment(seg, tmp);                  \
  73 }
  74
  75 static int
  76 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  77                    unsigned long *pax)
  78 {
  79         void __user *buf;
  80         unsigned int tmpflags;
  81         unsigned int err = 0;
  82
  83         /* Always make any pending restarted system calls return -EINTR */
  84         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  85
  86 #ifdef CONFIG_X86_32
  87         GET_SEG(gs);
  88         COPY_SEG(fs);
  89         COPY_SEG(es);
  90         COPY_SEG(ds);
  91 #endif /* CONFIG_X86_32 */
  92
  93         COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  94         COPY(dx); COPY(cx); COPY(ip);
  95
  96 #ifdef CONFIG_X86_64
  97         COPY(r8);
  98         COPY(r9);
  99         COPY(r10);
 100         COPY(r11);
 101         COPY(r12);
 102         COPY(r13);
 103         COPY(r14);
 104         COPY(r15);
 105 #endif /* CONFIG_X86_64 */
 106
 107 #ifdef CONFIG_X86_32
 108         COPY_SEG_CPL3(cs);
 109         COPY_SEG_CPL3(ss);
 110 #else /* !CONFIG_X86_32 */
 111         /* Kernel saves and restores only the CS segment register on signals,
 112          * which is the bare minimum needed to allow mixed 32/64-bit code.
 113          * App's signal handler can save/restore other segments if needed. */
 114         COPY_SEG_CPL3(cs);
 115 #endif /* CONFIG_X86_32 */
 116
 117         err |= __get_user(tmpflags, &sc->flags);
 118         regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 119         regs->orig_ax = -1;             /* disable syscall checks */
 120
 121         err |= __get_user(buf, &sc->fpstate);
 122         err |= restore_i387_xstate(buf);
 123
 124         err |= __get_user(*pax, &sc->ax);
 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 #ifdef CONFIG_X86_32
 135         {
 136                 unsigned int tmp;
 137
 138                 savesegment(gs, tmp);
 139                 err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
 140         }
 141         err |= __put_user(regs->fs, (unsigned int __user *)&sc->fs);
 142         err |= __put_user(regs->es, (unsigned int __user *)&sc->es);
 143         err |= __put_user(regs->ds, (unsigned int __user *)&sc->ds);
 144 #endif /* CONFIG_X86_32 */
 145
 146         err |= __put_user(regs->di, &sc->di);
 147         err |= __put_user(regs->si, &sc->si);
 148         err |= __put_user(regs->bp, &sc->bp);
 149         err |= __put_user(regs->sp, &sc->sp);
 150         err |= __put_user(regs->bx, &sc->bx);
 151         err |= __put_user(regs->dx, &sc->dx);
 152         err |= __put_user(regs->cx, &sc->cx);
 153         err |= __put_user(regs->ax, &sc->ax);
 154 #ifdef CONFIG_X86_64
 155         err |= __put_user(regs->r8, &sc->r8);
 156         err |= __put_user(regs->r9, &sc->r9);
 157         err |= __put_user(regs->r10, &sc->r10);
 158         err |= __put_user(regs->r11, &sc->r11);
 159         err |= __put_user(regs->r12, &sc->r12);
 160         err |= __put_user(regs->r13, &sc->r13);
 161         err |= __put_user(regs->r14, &sc->r14);
 162         err |= __put_user(regs->r15, &sc->r15);
 163 #endif /* CONFIG_X86_64 */
 164
 165         err |= __put_user(current->thread.trap_no, &sc->trapno);
 166         err |= __put_user(current->thread.error_code, &sc->err);
 167         err |= __put_user(regs->ip, &sc->ip);
 168 #ifdef CONFIG_X86_32
 169         err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
 170         err |= __put_user(regs->flags, &sc->flags);
 171         err |= __put_user(regs->sp, &sc->sp_at_signal);
 172         err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
 173 #else /* !CONFIG_X86_32 */
 174         err |= __put_user(regs->flags, &sc->flags);
 175         err |= __put_user(regs->cs, &sc->cs);
 176         err |= __put_user(0, &sc->gs);
 177         err |= __put_user(0, &sc->fs);
 178 #endif /* CONFIG_X86_32 */
 179
 180         err |= __put_user(fpstate, &sc->fpstate);
 181
 182         /* non-iBCS2 extensions.. */
 183         err |= __put_user(mask, &sc->oldmask);
 184         err |= __put_user(current->thread.cr2, &sc->cr2);
 185
 186         return err;
 187 }
 188
 189 /*
 190  * Set up a signal frame.
 191  */
 192 #ifdef CONFIG_X86_32
 193 static const struct {
 194         u16 poplmovl;
 195         u32 val;
 196         u16 int80;
 197 } __attribute__((packed)) retcode = {
 198         0xb858,         /* popl %eax; movl $..., %eax */
 199         __NR_sigreturn,
 200         0x80cd,         /* int $0x80 */
 201 };
 202
 203 static const struct {
 204         u8  movl;
 205         u32 val;
 206         u16 int80;
 207         u8  pad;
 208 } __attribute__((packed)) rt_retcode = {
 209         0xb8,           /* movl $..., %eax */
 210         __NR_rt_sigreturn,
 211         0x80cd,         /* int $0x80 */
 212         0
 213 };
 214
 215 /*
 216  * Determine which stack to use..
 217  */
 218 static inline void __user *
 219 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 220              void **fpstate)
 221 {
 222         unsigned long sp;
 223
 224         /* Default to using normal stack */
 225         sp = regs->sp;
 226
 227         /*
 228          * If we are on the alternate signal stack and would overflow it, don't.
 229          * Return an always-bogus address instead so we will die with SIGSEGV.
 230          */
 231         if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
 232                 return (void __user *) -1L;
 233
 234         /* This is the X/Open sanctioned signal stack switching.  */
 235         if (ka->sa.sa_flags & SA_ONSTACK) {
 236                 if (sas_ss_flags(sp) == 0)
 237                         sp = current->sas_ss_sp + current->sas_ss_size;
 238         } else {
 239                 /* This is the legacy signal stack switching. */
 240                 if ((regs->ss & 0xffff) != __USER_DS &&
 241                         !(ka->sa.sa_flags & SA_RESTORER) &&
 242                                 ka->sa.sa_restorer)
 243                         sp = (unsigned long) ka->sa.sa_restorer;
 244         }
 245
 246         if (used_math()) {
 247                 sp = sp - sig_xstate_size;
 248                 *fpstate = (struct _fpstate *) sp;
 249                 if (save_i387_xstate(*fpstate) < 0)
 250                         return (void __user *)-1L;
 251         }
 252
 253         sp -= frame_size;
 254         /*
 255          * Align the stack pointer according to the i386 ABI,
 256          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 257          */
 258         sp = ((sp + 4) & -16ul) - 4;
 259
 260         return (void __user *) sp;
 261 }
 262
 263 static int
 264 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 265               struct pt_regs *regs)
 266 {
 267         struct sigframe __user *frame;
 268         void __user *restorer;
 269         int err = 0;
 270         void __user *fpstate = NULL;
 271
 272         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 273
 274         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 275                 return -EFAULT;
 276
 277         if (__put_user(sig, &frame->sig))
 278                 return -EFAULT;
 279
 280         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 281                 return -EFAULT;
 282
 283         if (_NSIG_WORDS > 1) {
 284                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 285                                    sizeof(frame->extramask)))
 286                         return -EFAULT;
 287         }
 288
 289         if (current->mm->context.vdso)
 290                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 291         else
 292                 restorer = &frame->retcode;
 293         if (ka->sa.sa_flags & SA_RESTORER)
 294                 restorer = ka->sa.sa_restorer;
 295
 296         /* Set up to return from userspace.  */
 297         err |= __put_user(restorer, &frame->pretcode);
 298
 299         /*
 300          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 301          *
 302          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 303          * reasons and because gdb uses it as a signature to notice
 304          * signal handler stack frames.
 305          */
 306         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 307
 308         if (err)
 309                 return -EFAULT;
 310
 311         /* Set up registers for signal handler */
 312         regs->sp = (unsigned long)frame;
 313         regs->ip = (unsigned long)ka->sa.sa_handler;
 314         regs->ax = (unsigned long)sig;
 315         regs->dx = 0;
 316         regs->cx = 0;
 317
 318         regs->ds = __USER_DS;
 319         regs->es = __USER_DS;
 320         regs->ss = __USER_DS;
 321         regs->cs = __USER_CS;
 322
 323         return 0;
 324 }
 325
 326 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 327                             sigset_t *set, struct pt_regs *regs)
 328 {
 329         struct rt_sigframe __user *frame;
 330         void __user *restorer;
 331         int err = 0;
 332         void __user *fpstate = NULL;
 333
 334         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 335
 336         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 337                 return -EFAULT;
 338
 339         err |= __put_user(sig, &frame->sig);
 340         err |= __put_user(&frame->info, &frame->pinfo);
 341         err |= __put_user(&frame->uc, &frame->puc);
 342         err |= copy_siginfo_to_user(&frame->info, info);
 343         if (err)
 344                 return -EFAULT;
 345
 346         /* Create the ucontext.  */
 347         if (cpu_has_xsave)
 348                 err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
 349         else
 350                 err |= __put_user(0, &frame->uc.uc_flags);
 351         err |= __put_user(0, &frame->uc.uc_link);
 352         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 353         err |= __put_user(sas_ss_flags(regs->sp),
 354                           &frame->uc.uc_stack.ss_flags);
 355         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 356         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 357                                 regs, set->sig[0]);
 358         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 359         if (err)
 360                 return -EFAULT;
 361
 362         /* Set up to return from userspace.  */
 363         restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 364         if (ka->sa.sa_flags & SA_RESTORER)
 365                 restorer = ka->sa.sa_restorer;
 366         err |= __put_user(restorer, &frame->pretcode);
 367
 368         /*
 369          * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 370          *
 371          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 372          * reasons and because gdb uses it as a signature to notice
 373          * signal handler stack frames.
 374          */
 375         err |= __put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 376
 377         if (err)
 378                 return -EFAULT;
 379
 380         /* Set up registers for signal handler */
 381         regs->sp = (unsigned long)frame;
 382         regs->ip = (unsigned long)ka->sa.sa_handler;
 383         regs->ax = (unsigned long)sig;
 384         regs->dx = (unsigned long)&frame->info;
 385         regs->cx = (unsigned long)&frame->uc;
 386
 387         regs->ds = __USER_DS;
 388         regs->es = __USER_DS;
 389         regs->ss = __USER_DS;
 390         regs->cs = __USER_CS;
 391
 392         return 0;
 393 }
 394 #else /* !CONFIG_X86_32 */
 395 /*
 396  * Determine which stack to use..
 397  */
 398 static void __user *
 399 get_stack(struct k_sigaction *ka, unsigned long sp, unsigned long size)
 400 {
 401         /* Default to using normal stack - redzone*/
 402         sp -= 128;
 403
 404         /* This is the X/Open sanctioned signal stack switching.  */
 405         if (ka->sa.sa_flags & SA_ONSTACK) {
 406                 if (sas_ss_flags(sp) == 0)
 407                         sp = current->sas_ss_sp + current->sas_ss_size;
 408         }
 409
 410         return (void __user *)round_down(sp - size, 64);
 411 }
 412
 413 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 414                             sigset_t *set, struct pt_regs *regs)
 415 {
 416         struct rt_sigframe __user *frame;
 417         void __user *fp = NULL;
 418         int err = 0;
 419         struct task_struct *me = current;
 420
 421         if (used_math()) {
 422                 fp = get_stack(ka, regs->sp, sig_xstate_size);
 423                 frame = (void __user *)round_down(
 424                         (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
 425
 426                 if (save_i387_xstate(fp) < 0)
 427                         return -EFAULT;
 428         } else
 429                 frame = get_stack(ka, regs->sp, sizeof(struct rt_sigframe)) - 8;
 430
 431         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 432                 return -EFAULT;
 433
 434         if (ka->sa.sa_flags & SA_SIGINFO) {
 435                 if (copy_siginfo_to_user(&frame->info, info))
 436                         return -EFAULT;
 437         }
 438
 439         /* Create the ucontext.  */
 440         if (cpu_has_xsave)
 441                 err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
 442         else
 443                 err |= __put_user(0, &frame->uc.uc_flags);
 444         err |= __put_user(0, &frame->uc.uc_link);
 445         err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 446         err |= __put_user(sas_ss_flags(regs->sp),
 447                           &frame->uc.uc_stack.ss_flags);
 448         err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 449         err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 450         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 451
 452         /* Set up to return from userspace.  If provided, use a stub
 453            already in userspace.  */
 454         /* x86-64 should always use SA_RESTORER. */
 455         if (ka->sa.sa_flags & SA_RESTORER) {
 456                 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
 457         } else {
 458                 /* could use a vstub here */
 459                 return -EFAULT;
 460         }
 461
 462         if (err)
 463                 return -EFAULT;
 464
 465         /* Set up registers for signal handler */
 466         regs->di = sig;
 467         /* In case the signal handler was declared without prototypes */
 468         regs->ax = 0;
 469
 470         /* This also works for non SA_SIGINFO handlers because they expect the
 471            next argument after the signal number on the stack. */
 472         regs->si = (unsigned long)&frame->info;
 473         regs->dx = (unsigned long)&frame->uc;
 474         regs->ip = (unsigned long) ka->sa.sa_handler;
 475
 476         regs->sp = (unsigned long)frame;
 477
 478         /* Set up the CS register to run signal handlers in 64-bit mode,
 479            even if the handler happens to be interrupting 32-bit code. */
 480         regs->cs = __USER_CS;
 481
 482         return 0;
 483 }
 484 #endif /* CONFIG_X86_32 */
 485
 486 #ifdef CONFIG_X86_32
 487 /*
 488  * Atomically swap in the new signal mask, and wait for a signal.
 489  */
 490 asmlinkage int
 491 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 492 {
 493         mask &= _BLOCKABLE;
 494         spin_lock_irq(&current->sighand->siglock);
 495         current->saved_sigmask = current->blocked;
 496         siginitset(&current->blocked, mask);
 497         recalc_sigpending();
 498         spin_unlock_irq(&current->sighand->siglock);
 499
 500         current->state = TASK_INTERRUPTIBLE;
 501         schedule();
 502         set_restore_sigmask();
 503
 504         return -ERESTARTNOHAND;
 505 }
 506
 507 asmlinkage int
 508 sys_sigaction(int sig, const struct old_sigaction __user *act,
 509               struct old_sigaction __user *oact)
 510 {
 511         struct k_sigaction new_ka, old_ka;
 512         int ret;
 513
 514         if (act) {
 515                 old_sigset_t mask;
 516
 517                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 518                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 519                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 520                         return -EFAULT;
 521
 522                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 523                 __get_user(mask, &act->sa_mask);
 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                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 532                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 533                         return -EFAULT;
 534
 535                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 536                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 537         }
 538
 539         return ret;
 540 }
 541 #endif /* CONFIG_X86_32 */
 542
 543 #ifdef CONFIG_X86_32
 544 asmlinkage int sys_sigaltstack(unsigned long bx)
 545 {
 546         /*
 547          * This is needed to make gcc realize it doesn't own the
 548          * "struct pt_regs"
 549          */
 550         struct pt_regs *regs = (struct pt_regs *)&bx;
 551         const stack_t __user *uss = (const stack_t __user *)bx;
 552         stack_t __user *uoss = (stack_t __user *)regs->cx;
 553
 554         return do_sigaltstack(uss, uoss, regs->sp);
 555 }
 556 #else /* !CONFIG_X86_32 */
 557 asmlinkage long
 558 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 559                 struct pt_regs *regs)
 560 {
 561         return do_sigaltstack(uss, uoss, regs->sp);
 562 }
 563 #endif /* CONFIG_X86_32 */
 564
 565 /*
 566  * Do a signal return; undo the signal stack.
 567  */
 568 #ifdef CONFIG_X86_32
 569 asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
 570 {
 571         struct sigframe __user *frame;
 572         struct pt_regs *regs;
 573         unsigned long ax;
 574         sigset_t set;
 575
 576         regs = (struct pt_regs *) &__unused;
 577         frame = (struct sigframe __user *)(regs->sp - 8);
 578
 579         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 580                 goto badframe;
 581         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 582                 && __copy_from_user(&set.sig[1], &frame->extramask,
 583                                     sizeof(frame->extramask))))
 584                 goto badframe;
 585
 586         sigdelsetmask(&set, ~_BLOCKABLE);
 587         spin_lock_irq(&current->sighand->siglock);
 588         current->blocked = set;
 589         recalc_sigpending();
 590         spin_unlock_irq(&current->sighand->siglock);
 591
 592         if (restore_sigcontext(regs, &frame->sc, &ax))
 593                 goto badframe;
 594         return ax;
 595
 596 badframe:
 597         signal_fault(regs, frame, "sigreturn");
 598
 599         return 0;
 600 }
 601 #endif /* CONFIG_X86_32 */
 602
 603 static long do_rt_sigreturn(struct pt_regs *regs)
 604 {
 605         struct rt_sigframe __user *frame;
 606         unsigned long ax;
 607         sigset_t set;
 608
 609         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 610         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 611                 goto badframe;
 612         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 613                 goto badframe;
 614
 615         sigdelsetmask(&set, ~_BLOCKABLE);
 616         spin_lock_irq(&current->sighand->siglock);
 617         current->blocked = set;
 618         recalc_sigpending();
 619         spin_unlock_irq(&current->sighand->siglock);
 620
 621         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 622                 goto badframe;
 623
 624         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 625                 goto badframe;
 626
 627         return ax;
 628
 629 badframe:
 630         signal_fault(regs, frame, "rt_sigreturn");
 631         return 0;
 632 }
 633
 634 #ifdef CONFIG_X86_32
 635 asmlinkage int sys_rt_sigreturn(struct pt_regs regs)
 636 {
 637         return do_rt_sigreturn(&regs);
 638 }
 639 #else /* !CONFIG_X86_32 */
 640 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 641 {
 642         return do_rt_sigreturn(regs);
 643 }
 644 #endif /* CONFIG_X86_32 */
 645
 646 /*
 647  * OK, we're invoking a handler:
 648  */
 649 static int signr_convert(int sig)
 650 {
 651 #ifdef CONFIG_X86_32
 652         struct thread_info *info = current_thread_info();
 653
 654         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 655                 return info->exec_domain->signal_invmap[sig];
 656 #endif /* CONFIG_X86_32 */
 657         return sig;
 658 }
 659
 660 #ifdef CONFIG_X86_32
 661
 662 #define is_ia32 1
 663 #define ia32_setup_frame        __setup_frame
 664 #define ia32_setup_rt_frame     __setup_rt_frame
 665
 666 #else /* !CONFIG_X86_32 */
 667
 668 #ifdef CONFIG_IA32_EMULATION
 669 #define is_ia32 test_thread_flag(TIF_IA32)
 670 #else /* !CONFIG_IA32_EMULATION */
 671 #define is_ia32 0
 672 #endif /* CONFIG_IA32_EMULATION */
 673
 674 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 675                 sigset_t *set, struct pt_regs *regs);
 676 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 677                 sigset_t *set, struct pt_regs *regs);
 678
 679 #endif /* CONFIG_X86_32 */
 680
 681 static int
 682 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 683                sigset_t *set, struct pt_regs *regs)
 684 {
 685         int usig = signr_convert(sig);
 686         int ret;
 687
 688         /* Set up the stack frame */
 689         if (is_ia32) {
 690                 if (ka->sa.sa_flags & SA_SIGINFO)
 691                         ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
 692                 else
 693                         ret = ia32_setup_frame(usig, ka, set, regs);
 694         } else
 695                 ret = __setup_rt_frame(sig, ka, info, set, regs);
 696
 697         if (ret) {
 698                 force_sigsegv(sig, current);
 699                 return -EFAULT;
 700         }
 701
 702         return ret;
 703 }
 704
 705 static int
 706 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 707               sigset_t *oldset, struct pt_regs *regs)
 708 {
 709         int ret;
 710
 711         /* Are we from a system call? */
 712         if (syscall_get_nr(current, regs) >= 0) {
 713                 /* If so, check system call restarting.. */
 714                 switch (syscall_get_error(current, regs)) {
 715                 case -ERESTART_RESTARTBLOCK:
 716                 case -ERESTARTNOHAND:
 717                         regs->ax = -EINTR;
 718                         break;
 719
 720                 case -ERESTARTSYS:
 721                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 722                                 regs->ax = -EINTR;
 723                                 break;
 724                         }
 725                 /* fallthrough */
 726                 case -ERESTARTNOINTR:
 727                         regs->ax = regs->orig_ax;
 728                         regs->ip -= 2;
 729                         break;
 730                 }
 731         }
 732
 733         /*
 734          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 735          * flag so that register information in the sigcontext is correct.
 736          */
 737         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 738             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 739                 regs->flags &= ~X86_EFLAGS_TF;
 740
 741         ret = setup_rt_frame(sig, ka, info, oldset, regs);
 742
 743         if (ret)
 744                 return ret;
 745
 746 #ifdef CONFIG_X86_64
 747         /*
 748          * This has nothing to do with segment registers,
 749          * despite the name.  This magic affects uaccess.h
 750          * macros' behavior.  Reset it to the normal setting.
 751          */
 752         set_fs(USER_DS);
 753 #endif
 754
 755         /*
 756          * Clear the direction flag as per the ABI for function entry.
 757          */
 758         regs->flags &= ~X86_EFLAGS_DF;
 759
 760         /*
 761          * Clear TF when entering the signal handler, but
 762          * notify any tracer that was single-stepping it.
 763          * The tracer may want to single-step inside the
 764          * handler too.
 765          */
 766         regs->flags &= ~X86_EFLAGS_TF;
 767
 768         spin_lock_irq(&current->sighand->siglock);
 769         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 770         if (!(ka->sa.sa_flags & SA_NODEFER))
 771                 sigaddset(&current->blocked, sig);
 772         recalc_sigpending();
 773         spin_unlock_irq(&current->sighand->siglock);
 774
 775         tracehook_signal_handler(sig, info, ka, regs,
 776                                  test_thread_flag(TIF_SINGLESTEP));
 777
 778         return 0;
 779 }
 780
 781 #ifdef CONFIG_X86_32
 782 #define NR_restart_syscall      __NR_restart_syscall
 783 #else /* !CONFIG_X86_32 */
 784 #define NR_restart_syscall      \
 785         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 786 #endif /* CONFIG_X86_32 */
 787
 788 /*
 789  * Note that 'init' is a special process: it doesn't get signals it doesn't
 790  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 791  * mistake.
 792  */
 793 static void do_signal(struct pt_regs *regs)
 794 {
 795         struct k_sigaction ka;
 796         siginfo_t info;
 797         int signr;
 798         sigset_t *oldset;
 799
 800         /*
 801          * We want the common case to go fast, which is why we may in certain
 802          * cases get here from kernel mode. Just return without doing anything
 803          * if so.
 804          * X86_32: vm86 regs switched out by assembly code before reaching
 805          * here, so testing against kernel CS suffices.
 806          */
 807         if (!user_mode(regs))
 808                 return;
 809
 810         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 811                 oldset = &current->saved_sigmask;
 812         else
 813                 oldset = &current->blocked;
 814
 815         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 816         if (signr > 0) {
 817                 /*
 818                  * Re-enable any watchpoints before delivering the
 819                  * signal to user space. The processor register will
 820                  * have been cleared if the watchpoint triggered
 821                  * inside the kernel.
 822                  */
 823                 if (current->thread.debugreg7)
 824                         set_debugreg(current->thread.debugreg7, 7);
 825
 826                 /* Whee! Actually deliver the signal.  */
 827                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 828                         /*
 829                          * A signal was successfully delivered; the saved
 830                          * sigmask will have been stored in the signal frame,
 831                          * and will be restored by sigreturn, so we can simply
 832                          * clear the TS_RESTORE_SIGMASK flag.
 833                          */
 834                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 835                 }
 836                 return;
 837         }
 838
 839         /* Did we come from a system call? */
 840         if (syscall_get_nr(current, regs) >= 0) {
 841                 /* Restart the system call - no handlers present */
 842                 switch (syscall_get_error(current, regs)) {
 843                 case -ERESTARTNOHAND:
 844                 case -ERESTARTSYS:
 845                 case -ERESTARTNOINTR:
 846                         regs->ax = regs->orig_ax;
 847                         regs->ip -= 2;
 848                         break;
 849
 850                 case -ERESTART_RESTARTBLOCK:
 851                         regs->ax = NR_restart_syscall;
 852                         regs->ip -= 2;
 853                         break;
 854                 }
 855         }
 856
 857         /*
 858          * If there's no signal to deliver, we just put the saved sigmask
 859          * back.
 860          */
 861         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 862                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 863                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 864         }
 865 }
 866
 867 /*
 868  * notification of userspace execution resumption
 869  * - triggered by the TIF_WORK_MASK flags
 870  */
 871 void
 872 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 873 {
 874 #if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
 875         /* notify userspace of pending MCEs */
 876         if (thread_info_flags & _TIF_MCE_NOTIFY)
 877                 mce_notify_user();
 878 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 879
 880         /* deal with pending signal delivery */
 881         if (thread_info_flags & _TIF_SIGPENDING)
 882                 do_signal(regs);
 883
 884         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 885                 clear_thread_flag(TIF_NOTIFY_RESUME);
 886                 tracehook_notify_resume(regs);
 887         }
 888
 889 #ifdef CONFIG_X86_32
 890         clear_thread_flag(TIF_IRET);
 891 #endif /* CONFIG_X86_32 */
 892 }
 893
 894 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 895 {
 896         struct task_struct *me = current;
 897
 898         if (show_unhandled_signals && printk_ratelimit()) {
 899                 printk("%s"
 900                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 901                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 902                        me->comm, me->pid, where, frame,
 903                        regs->ip, regs->sp, regs->orig_ax);
 904                 print_vma_addr(" in ", regs->ip);
 905                 printk(KERN_CONT "\n");
 906         }
 907
 908         force_sig(SIGSEGV, me);
 909 }