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
  23 #include <asm/processor.h>
  24 #include <asm/ucontext.h>
  25 #include <asm/i387.h>
  26 #include <asm/vdso.h>
  27 #include <asm/mce.h>
  28
  29 #ifdef CONFIG_X86_64
  30 #include <asm/proto.h>
  31 #include <asm/ia32_unistd.h>
  32 #endif /* CONFIG_X86_64 */
  33
  34 #include <asm/syscall.h>
  35 #include <asm/syscalls.h>
  36
  37 #include <asm/sigframe.h>
  38
  39 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  40
  41 #define __FIX_EFLAGS    (X86_EFLAGS_AC | X86_EFLAGS_OF | \
  42                          X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
  43                          X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
  44                          X86_EFLAGS_CF)
  45
  46 #ifdef CONFIG_X86_32
  47 # define FIX_EFLAGS     (__FIX_EFLAGS | X86_EFLAGS_RF)
  48 #else
  49 # define FIX_EFLAGS     __FIX_EFLAGS
  50 #endif
  51
  52 #define COPY(x)                 do {                    \
  53         get_user_ex(regs->x, &sc->x);                   \
  54 } while (0)
  55
  56 #define GET_SEG(seg)            ({                      \
  57         unsigned short tmp;                             \
  58         get_user_ex(tmp, &sc->seg);                     \
  59         tmp;                                            \
  60 })
  61
  62 #define COPY_SEG(seg)           do {                    \
  63         regs->seg = GET_SEG(seg);                       \
  64 } while (0)
  65
  66 #define COPY_SEG_CPL3(seg)      do {                    \
  67         regs->seg = GET_SEG(seg) | 3;                   \
  68 } while (0)
  69
  70 static int
  71 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  72                    unsigned long *pax)
  73 {
  74         void __user *buf;
  75         unsigned int tmpflags;
  76         unsigned int err = 0;
  77
  78         /* Always make any pending restarted system calls return -EINTR */
  79         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  80
  81         get_user_try {
  82
  83 #ifdef CONFIG_X86_32
  84                 set_user_gs(regs, GET_SEG(gs));
  85                 COPY_SEG(fs);
  86                 COPY_SEG(es);
  87                 COPY_SEG(ds);
  88 #endif /* CONFIG_X86_32 */
  89
  90                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  91                 COPY(dx); COPY(cx); COPY(ip);
  92
  93 #ifdef CONFIG_X86_64
  94                 COPY(r8);
  95                 COPY(r9);
  96                 COPY(r10);
  97                 COPY(r11);
  98                 COPY(r12);
  99                 COPY(r13);
 100                 COPY(r14);
 101                 COPY(r15);
 102 #endif /* CONFIG_X86_64 */
 103
 104 #ifdef CONFIG_X86_32
 105                 COPY_SEG_CPL3(cs);
 106                 COPY_SEG_CPL3(ss);
 107 #else /* !CONFIG_X86_32 */
 108                 /* Kernel saves and restores only the CS segment register on signals,
 109                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 110                  * App's signal handler can save/restore other segments if needed. */
 111                 COPY_SEG_CPL3(cs);
 112 #endif /* CONFIG_X86_32 */
 113
 114                 get_user_ex(tmpflags, &sc->flags);
 115                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 116                 regs->orig_ax = -1;             /* disable syscall checks */
 117
 118                 get_user_ex(buf, &sc->fpstate);
 119                 err |= restore_i387_xstate(buf);
 120
 121                 get_user_ex(*pax, &sc->ax);
 122         } get_user_catch(err);
 123
 124         return err;
 125 }
 126
 127 static int
 128 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 129                  struct pt_regs *regs, unsigned long mask)
 130 {
 131         int err = 0;
 132
 133         put_user_try {
 134
 135 #ifdef CONFIG_X86_32
 136                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 137                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 138                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 139                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 140 #endif /* CONFIG_X86_32 */
 141
 142                 put_user_ex(regs->di, &sc->di);
 143                 put_user_ex(regs->si, &sc->si);
 144                 put_user_ex(regs->bp, &sc->bp);
 145                 put_user_ex(regs->sp, &sc->sp);
 146                 put_user_ex(regs->bx, &sc->bx);
 147                 put_user_ex(regs->dx, &sc->dx);
 148                 put_user_ex(regs->cx, &sc->cx);
 149                 put_user_ex(regs->ax, &sc->ax);
 150 #ifdef CONFIG_X86_64
 151                 put_user_ex(regs->r8, &sc->r8);
 152                 put_user_ex(regs->r9, &sc->r9);
 153                 put_user_ex(regs->r10, &sc->r10);
 154                 put_user_ex(regs->r11, &sc->r11);
 155                 put_user_ex(regs->r12, &sc->r12);
 156                 put_user_ex(regs->r13, &sc->r13);
 157                 put_user_ex(regs->r14, &sc->r14);
 158                 put_user_ex(regs->r15, &sc->r15);
 159 #endif /* CONFIG_X86_64 */
 160
 161                 put_user_ex(current->thread.trap_no, &sc->trapno);
 162                 put_user_ex(current->thread.error_code, &sc->err);
 163                 put_user_ex(regs->ip, &sc->ip);
 164 #ifdef CONFIG_X86_32
 165                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 166                 put_user_ex(regs->flags, &sc->flags);
 167                 put_user_ex(regs->sp, &sc->sp_at_signal);
 168                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 169 #else /* !CONFIG_X86_32 */
 170                 put_user_ex(regs->flags, &sc->flags);
 171                 put_user_ex(regs->cs, &sc->cs);
 172                 put_user_ex(0, &sc->gs);
 173                 put_user_ex(0, &sc->fs);
 174 #endif /* CONFIG_X86_32 */
 175
 176                 put_user_ex(fpstate, &sc->fpstate);
 177
 178                 /* non-iBCS2 extensions.. */
 179                 put_user_ex(mask, &sc->oldmask);
 180                 put_user_ex(current->thread.cr2, &sc->cr2);
 181         } put_user_catch(err);
 182
 183         return err;
 184 }
 185
 186 /*
 187  * Set up a signal frame.
 188  */
 189
 190 /*
 191  * Determine which stack to use..
 192  */
 193 static unsigned long align_sigframe(unsigned long sp)
 194 {
 195 #ifdef CONFIG_X86_32
 196         /*
 197          * Align the stack pointer according to the i386 ABI,
 198          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 199          */
 200         sp = ((sp + 4) & -16ul) - 4;
 201 #else /* !CONFIG_X86_32 */
 202         sp = round_down(sp, 16) - 8;
 203 #endif
 204         return sp;
 205 }
 206
 207 static inline void __user *
 208 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 209              void __user **fpstate)
 210 {
 211         /* Default to using normal stack */
 212         unsigned long sp = regs->sp;
 213         int onsigstack = on_sig_stack(sp);
 214
 215 #ifdef CONFIG_X86_64
 216         /* redzone */
 217         sp -= 128;
 218 #endif /* CONFIG_X86_64 */
 219
 220         if (!onsigstack) {
 221                 /* This is the X/Open sanctioned signal stack switching.  */
 222                 if (ka->sa.sa_flags & SA_ONSTACK) {
 223                         if (current->sas_ss_size)
 224                                 sp = current->sas_ss_sp + current->sas_ss_size;
 225                 } else {
 226 #ifdef CONFIG_X86_32
 227                         /* This is the legacy signal stack switching. */
 228                         if ((regs->ss & 0xffff) != __USER_DS &&
 229                                 !(ka->sa.sa_flags & SA_RESTORER) &&
 230                                         ka->sa.sa_restorer)
 231                                 sp = (unsigned long) ka->sa.sa_restorer;
 232 #endif /* CONFIG_X86_32 */
 233                 }
 234         }
 235
 236         if (used_math()) {
 237                 sp -= sig_xstate_size;
 238 #ifdef CONFIG_X86_64
 239                 sp = round_down(sp, 64);
 240 #endif /* CONFIG_X86_64 */
 241                 *fpstate = (void __user *)sp;
 242         }
 243
 244         sp = align_sigframe(sp - frame_size);
 245
 246         /*
 247          * If we are on the alternate signal stack and would overflow it, don't.
 248          * Return an always-bogus address instead so we will die with SIGSEGV.
 249          */
 250         if (onsigstack && !likely(on_sig_stack(sp)))
 251                 return (void __user *)-1L;
 252
 253         /* save i387 state */
 254         if (used_math() && save_i387_xstate(*fpstate) < 0)
 255                 return (void __user *)-1L;
 256
 257         return (void __user *)sp;
 258 }
 259
 260 #ifdef CONFIG_X86_32
 261 static const struct {
 262         u16 poplmovl;
 263         u32 val;
 264         u16 int80;
 265 } __attribute__((packed)) retcode = {
 266         0xb858,         /* popl %eax; movl $..., %eax */
 267         __NR_sigreturn,
 268         0x80cd,         /* int $0x80 */
 269 };
 270
 271 static const struct {
 272         u8  movl;
 273         u32 val;
 274         u16 int80;
 275         u8  pad;
 276 } __attribute__((packed)) rt_retcode = {
 277         0xb8,           /* movl $..., %eax */
 278         __NR_rt_sigreturn,
 279         0x80cd,         /* int $0x80 */
 280         0
 281 };
 282
 283 static int
 284 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 285               struct pt_regs *regs)
 286 {
 287         struct sigframe __user *frame;
 288         void __user *restorer;
 289         int err = 0;
 290         void __user *fpstate = NULL;
 291
 292         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 293
 294         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 295                 return -EFAULT;
 296
 297         if (__put_user(sig, &frame->sig))
 298                 return -EFAULT;
 299
 300         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 301                 return -EFAULT;
 302
 303         if (_NSIG_WORDS > 1) {
 304                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 305                                    sizeof(frame->extramask)))
 306                         return -EFAULT;
 307         }
 308
 309         if (current->mm->context.vdso)
 310                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 311         else
 312                 restorer = &frame->retcode;
 313         if (ka->sa.sa_flags & SA_RESTORER)
 314                 restorer = ka->sa.sa_restorer;
 315
 316         /* Set up to return from userspace.  */
 317         err |= __put_user(restorer, &frame->pretcode);
 318
 319         /*
 320          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 321          *
 322          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 323          * reasons and because gdb uses it as a signature to notice
 324          * signal handler stack frames.
 325          */
 326         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 327
 328         if (err)
 329                 return -EFAULT;
 330
 331         /* Set up registers for signal handler */
 332         regs->sp = (unsigned long)frame;
 333         regs->ip = (unsigned long)ka->sa.sa_handler;
 334         regs->ax = (unsigned long)sig;
 335         regs->dx = 0;
 336         regs->cx = 0;
 337
 338         regs->ds = __USER_DS;
 339         regs->es = __USER_DS;
 340         regs->ss = __USER_DS;
 341         regs->cs = __USER_CS;
 342
 343         return 0;
 344 }
 345
 346 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 347                             sigset_t *set, struct pt_regs *regs)
 348 {
 349         struct rt_sigframe __user *frame;
 350         void __user *restorer;
 351         int err = 0;
 352         void __user *fpstate = NULL;
 353
 354         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 355
 356         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 357                 return -EFAULT;
 358
 359         put_user_try {
 360                 put_user_ex(sig, &frame->sig);
 361                 put_user_ex(&frame->info, &frame->pinfo);
 362                 put_user_ex(&frame->uc, &frame->puc);
 363                 err |= copy_siginfo_to_user(&frame->info, info);
 364
 365                 /* Create the ucontext.  */
 366                 if (cpu_has_xsave)
 367                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 368                 else
 369                         put_user_ex(0, &frame->uc.uc_flags);
 370                 put_user_ex(0, &frame->uc.uc_link);
 371                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 372                 put_user_ex(sas_ss_flags(regs->sp),
 373                             &frame->uc.uc_stack.ss_flags);
 374                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 375                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 376                                         regs, set->sig[0]);
 377                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 378
 379                 /* Set up to return from userspace.  */
 380                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 381                 if (ka->sa.sa_flags & SA_RESTORER)
 382                         restorer = ka->sa.sa_restorer;
 383                 put_user_ex(restorer, &frame->pretcode);
 384
 385                 /*
 386                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 387                  *
 388                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 389                  * reasons and because gdb uses it as a signature to notice
 390                  * signal handler stack frames.
 391                  */
 392                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 393         } put_user_catch(err);
 394
 395         if (err)
 396                 return -EFAULT;
 397
 398         /* Set up registers for signal handler */
 399         regs->sp = (unsigned long)frame;
 400         regs->ip = (unsigned long)ka->sa.sa_handler;
 401         regs->ax = (unsigned long)sig;
 402         regs->dx = (unsigned long)&frame->info;
 403         regs->cx = (unsigned long)&frame->uc;
 404
 405         regs->ds = __USER_DS;
 406         regs->es = __USER_DS;
 407         regs->ss = __USER_DS;
 408         regs->cs = __USER_CS;
 409
 410         return 0;
 411 }
 412 #else /* !CONFIG_X86_32 */
 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         frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
 422
 423         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 424                 return -EFAULT;
 425
 426         if (ka->sa.sa_flags & SA_SIGINFO) {
 427                 if (copy_siginfo_to_user(&frame->info, info))
 428                         return -EFAULT;
 429         }
 430
 431         put_user_try {
 432                 /* Create the ucontext.  */
 433                 if (cpu_has_xsave)
 434                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 435                 else
 436                         put_user_ex(0, &frame->uc.uc_flags);
 437                 put_user_ex(0, &frame->uc.uc_link);
 438                 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 439                 put_user_ex(sas_ss_flags(regs->sp),
 440                             &frame->uc.uc_stack.ss_flags);
 441                 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 442                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 443                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 444
 445                 /* Set up to return from userspace.  If provided, use a stub
 446                    already in userspace.  */
 447                 /* x86-64 should always use SA_RESTORER. */
 448                 if (ka->sa.sa_flags & SA_RESTORER) {
 449                         put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 450                 } else {
 451                         /* could use a vstub here */
 452                         err |= -EFAULT;
 453                 }
 454         } put_user_catch(err);
 455
 456         if (err)
 457                 return -EFAULT;
 458
 459         /* Set up registers for signal handler */
 460         regs->di = sig;
 461         /* In case the signal handler was declared without prototypes */
 462         regs->ax = 0;
 463
 464         /* This also works for non SA_SIGINFO handlers because they expect the
 465            next argument after the signal number on the stack. */
 466         regs->si = (unsigned long)&frame->info;
 467         regs->dx = (unsigned long)&frame->uc;
 468         regs->ip = (unsigned long) ka->sa.sa_handler;
 469
 470         regs->sp = (unsigned long)frame;
 471
 472         /* Set up the CS register to run signal handlers in 64-bit mode,
 473            even if the handler happens to be interrupting 32-bit code. */
 474         regs->cs = __USER_CS;
 475
 476         return 0;
 477 }
 478 #endif /* CONFIG_X86_32 */
 479
 480 #ifdef CONFIG_X86_32
 481 /*
 482  * Atomically swap in the new signal mask, and wait for a signal.
 483  */
 484 asmlinkage int
 485 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 486 {
 487         mask &= _BLOCKABLE;
 488         spin_lock_irq(&current->sighand->siglock);
 489         current->saved_sigmask = current->blocked;
 490         siginitset(&current->blocked, mask);
 491         recalc_sigpending();
 492         spin_unlock_irq(&current->sighand->siglock);
 493
 494         current->state = TASK_INTERRUPTIBLE;
 495         schedule();
 496         set_restore_sigmask();
 497
 498         return -ERESTARTNOHAND;
 499 }
 500
 501 asmlinkage int
 502 sys_sigaction(int sig, const struct old_sigaction __user *act,
 503               struct old_sigaction __user *oact)
 504 {
 505         struct k_sigaction new_ka, old_ka;
 506         int ret = 0;
 507
 508         if (act) {
 509                 old_sigset_t mask;
 510
 511                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 512                         return -EFAULT;
 513
 514                 get_user_try {
 515                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 516                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 517                         get_user_ex(mask, &act->sa_mask);
 518                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 519                 } get_user_catch(ret);
 520
 521                 if (ret)
 522                         return -EFAULT;
 523                 siginitset(&new_ka.sa.sa_mask, mask);
 524         }
 525
 526         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 527
 528         if (!ret && oact) {
 529                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 530                         return -EFAULT;
 531
 532                 put_user_try {
 533                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 534                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 535                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 536                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 537                 } put_user_catch(ret);
 538
 539                 if (ret)
 540                         return -EFAULT;
 541         }
 542
 543         return ret;
 544 }
 545 #endif /* CONFIG_X86_32 */
 546
 547 #ifdef CONFIG_X86_32
 548 int sys_sigaltstack(struct pt_regs *regs)
 549 {
 550         const stack_t __user *uss = (const stack_t __user *)regs->bx;
 551         stack_t __user *uoss = (stack_t __user *)regs->cx;
 552
 553         return do_sigaltstack(uss, uoss, regs->sp);
 554 }
 555 #else /* !CONFIG_X86_32 */
 556 asmlinkage long
 557 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 558                 struct pt_regs *regs)
 559 {
 560         return do_sigaltstack(uss, uoss, regs->sp);
 561 }
 562 #endif /* CONFIG_X86_32 */
 563
 564 /*
 565  * Do a signal return; undo the signal stack.
 566  */
 567 #ifdef CONFIG_X86_32
 568 unsigned long sys_sigreturn(struct pt_regs *regs)
 569 {
 570         struct sigframe __user *frame;
 571         unsigned long ax;
 572         sigset_t set;
 573
 574         frame = (struct sigframe __user *)(regs->sp - 8);
 575
 576         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 577                 goto badframe;
 578         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 579                 && __copy_from_user(&set.sig[1], &frame->extramask,
 580                                     sizeof(frame->extramask))))
 581                 goto badframe;
 582
 583         sigdelsetmask(&set, ~_BLOCKABLE);
 584         spin_lock_irq(&current->sighand->siglock);
 585         current->blocked = set;
 586         recalc_sigpending();
 587         spin_unlock_irq(&current->sighand->siglock);
 588
 589         if (restore_sigcontext(regs, &frame->sc, &ax))
 590                 goto badframe;
 591         return ax;
 592
 593 badframe:
 594         signal_fault(regs, frame, "sigreturn");
 595
 596         return 0;
 597 }
 598 #endif /* CONFIG_X86_32 */
 599
 600 long sys_rt_sigreturn(struct pt_regs *regs)
 601 {
 602         struct rt_sigframe __user *frame;
 603         unsigned long ax;
 604         sigset_t set;
 605
 606         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 607         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 608                 goto badframe;
 609         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 610                 goto badframe;
 611
 612         sigdelsetmask(&set, ~_BLOCKABLE);
 613         spin_lock_irq(&current->sighand->siglock);
 614         current->blocked = set;
 615         recalc_sigpending();
 616         spin_unlock_irq(&current->sighand->siglock);
 617
 618         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 619                 goto badframe;
 620
 621         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 622                 goto badframe;
 623
 624         return ax;
 625
 626 badframe:
 627         signal_fault(regs, frame, "rt_sigreturn");
 628         return 0;
 629 }
 630
 631 /*
 632  * OK, we're invoking a handler:
 633  */
 634 static int signr_convert(int sig)
 635 {
 636 #ifdef CONFIG_X86_32
 637         struct thread_info *info = current_thread_info();
 638
 639         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 640                 return info->exec_domain->signal_invmap[sig];
 641 #endif /* CONFIG_X86_32 */
 642         return sig;
 643 }
 644
 645 #ifdef CONFIG_X86_32
 646
 647 #define is_ia32 1
 648 #define ia32_setup_frame        __setup_frame
 649 #define ia32_setup_rt_frame     __setup_rt_frame
 650
 651 #else /* !CONFIG_X86_32 */
 652
 653 #ifdef CONFIG_IA32_EMULATION
 654 #define is_ia32 test_thread_flag(TIF_IA32)
 655 #else /* !CONFIG_IA32_EMULATION */
 656 #define is_ia32 0
 657 #endif /* CONFIG_IA32_EMULATION */
 658
 659 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 660                 sigset_t *set, struct pt_regs *regs);
 661 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 662                 sigset_t *set, struct pt_regs *regs);
 663
 664 #endif /* CONFIG_X86_32 */
 665
 666 static int
 667 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 668                sigset_t *set, struct pt_regs *regs)
 669 {
 670         int usig = signr_convert(sig);
 671         int ret;
 672
 673         /* Set up the stack frame */
 674         if (is_ia32) {
 675                 if (ka->sa.sa_flags & SA_SIGINFO)
 676                         ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
 677                 else
 678                         ret = ia32_setup_frame(usig, ka, set, regs);
 679         } else
 680                 ret = __setup_rt_frame(sig, ka, info, set, regs);
 681
 682         if (ret) {
 683                 force_sigsegv(sig, current);
 684                 return -EFAULT;
 685         }
 686
 687         return ret;
 688 }
 689
 690 static int
 691 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 692               sigset_t *oldset, struct pt_regs *regs)
 693 {
 694         int ret;
 695
 696         /* Are we from a system call? */
 697         if (syscall_get_nr(current, regs) >= 0) {
 698                 /* If so, check system call restarting.. */
 699                 switch (syscall_get_error(current, regs)) {
 700                 case -ERESTART_RESTARTBLOCK:
 701                 case -ERESTARTNOHAND:
 702                         regs->ax = -EINTR;
 703                         break;
 704
 705                 case -ERESTARTSYS:
 706                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 707                                 regs->ax = -EINTR;
 708                                 break;
 709                         }
 710                 /* fallthrough */
 711                 case -ERESTARTNOINTR:
 712                         regs->ax = regs->orig_ax;
 713                         regs->ip -= 2;
 714                         break;
 715                 }
 716         }
 717
 718         /*
 719          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 720          * flag so that register information in the sigcontext is correct.
 721          */
 722         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 723             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 724                 regs->flags &= ~X86_EFLAGS_TF;
 725
 726         ret = setup_rt_frame(sig, ka, info, oldset, regs);
 727
 728         if (ret)
 729                 return ret;
 730
 731 #ifdef CONFIG_X86_64
 732         /*
 733          * This has nothing to do with segment registers,
 734          * despite the name.  This magic affects uaccess.h
 735          * macros' behavior.  Reset it to the normal setting.
 736          */
 737         set_fs(USER_DS);
 738 #endif
 739
 740         /*
 741          * Clear the direction flag as per the ABI for function entry.
 742          */
 743         regs->flags &= ~X86_EFLAGS_DF;
 744
 745         /*
 746          * Clear TF when entering the signal handler, but
 747          * notify any tracer that was single-stepping it.
 748          * The tracer may want to single-step inside the
 749          * handler too.
 750          */
 751         regs->flags &= ~X86_EFLAGS_TF;
 752
 753         spin_lock_irq(&current->sighand->siglock);
 754         sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
 755         if (!(ka->sa.sa_flags & SA_NODEFER))
 756                 sigaddset(&current->blocked, sig);
 757         recalc_sigpending();
 758         spin_unlock_irq(&current->sighand->siglock);
 759
 760         tracehook_signal_handler(sig, info, ka, regs,
 761                                  test_thread_flag(TIF_SINGLESTEP));
 762
 763         return 0;
 764 }
 765
 766 #ifdef CONFIG_X86_32
 767 #define NR_restart_syscall      __NR_restart_syscall
 768 #else /* !CONFIG_X86_32 */
 769 #define NR_restart_syscall      \
 770         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 771 #endif /* CONFIG_X86_32 */
 772
 773 /*
 774  * Note that 'init' is a special process: it doesn't get signals it doesn't
 775  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 776  * mistake.
 777  */
 778 static void do_signal(struct pt_regs *regs)
 779 {
 780         struct k_sigaction ka;
 781         siginfo_t info;
 782         int signr;
 783         sigset_t *oldset;
 784
 785         /*
 786          * We want the common case to go fast, which is why we may in certain
 787          * cases get here from kernel mode. Just return without doing anything
 788          * if so.
 789          * X86_32: vm86 regs switched out by assembly code before reaching
 790          * here, so testing against kernel CS suffices.
 791          */
 792         if (!user_mode(regs))
 793                 return;
 794
 795         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 796                 oldset = &current->saved_sigmask;
 797         else
 798                 oldset = &current->blocked;
 799
 800         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 801         if (signr > 0) {
 802                 /*
 803                  * Re-enable any watchpoints before delivering the
 804                  * signal to user space. The processor register will
 805                  * have been cleared if the watchpoint triggered
 806                  * inside the kernel.
 807                  */
 808                 if (current->thread.debugreg7)
 809                         set_debugreg(current->thread.debugreg7, 7);
 810
 811                 /* Whee! Actually deliver the signal.  */
 812                 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 813                         /*
 814                          * A signal was successfully delivered; the saved
 815                          * sigmask will have been stored in the signal frame,
 816                          * and will be restored by sigreturn, so we can simply
 817                          * clear the TS_RESTORE_SIGMASK flag.
 818                          */
 819                         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 820                 }
 821                 return;
 822         }
 823
 824         /* Did we come from a system call? */
 825         if (syscall_get_nr(current, regs) >= 0) {
 826                 /* Restart the system call - no handlers present */
 827                 switch (syscall_get_error(current, regs)) {
 828                 case -ERESTARTNOHAND:
 829                 case -ERESTARTSYS:
 830                 case -ERESTARTNOINTR:
 831                         regs->ax = regs->orig_ax;
 832                         regs->ip -= 2;
 833                         break;
 834
 835                 case -ERESTART_RESTARTBLOCK:
 836                         regs->ax = NR_restart_syscall;
 837                         regs->ip -= 2;
 838                         break;
 839                 }
 840         }
 841
 842         /*
 843          * If there's no signal to deliver, we just put the saved sigmask
 844          * back.
 845          */
 846         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 847                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 848                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 849         }
 850 }
 851
 852 /*
 853  * notification of userspace execution resumption
 854  * - triggered by the TIF_WORK_MASK flags
 855  */
 856 void
 857 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 858 {
 859 #ifdef CONFIG_X86_MCE
 860         /* notify userspace of pending MCEs */
 861         if (thread_info_flags & _TIF_MCE_NOTIFY)
 862                 mce_notify_process();
 863 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 864
 865         /* deal with pending signal delivery */
 866         if (thread_info_flags & _TIF_SIGPENDING)
 867                 do_signal(regs);
 868
 869         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 870                 clear_thread_flag(TIF_NOTIFY_RESUME);
 871                 tracehook_notify_resume(regs);
 872                 if (current->replacement_session_keyring)
 873                         key_replace_session_keyring();
 874         }
 875
 876 #ifdef CONFIG_X86_32
 877         clear_thread_flag(TIF_IRET);
 878 #endif /* CONFIG_X86_32 */
 879 }
 880
 881 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 882 {
 883         struct task_struct *me = current;
 884
 885         if (show_unhandled_signals && printk_ratelimit()) {
 886                 printk("%s"
 887                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 888                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 889                        me->comm, me->pid, where, frame,
 890                        regs->ip, regs->sp, regs->orig_ax);
 891                 print_vma_addr(" in ", regs->ip);
 892                 printk(KERN_CONT "\n");
 893         }
 894
 895         force_sig(SIGSEGV, me);
 896 }