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/errno.h>
  14 #include <linux/wait.h>
  15 #include <linux/tracehook.h>
  16 #include <linux/unistd.h>
  17 #include <linux/stddef.h>
  18 #include <linux/personality.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/user-return-notifier.h>
  21
  22 #include <asm/processor.h>
  23 #include <asm/ucontext.h>
  24 #include <asm/i387.h>
  25 #include <asm/vdso.h>
  26 #include <asm/mce.h>
  27 #include <asm/sighandling.h>
  28
  29 #ifdef CONFIG_X86_64
  30 #include <asm/proto.h>
  31 #include <asm/ia32_unistd.h>
  32 #include <asm/sys_ia32.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 #ifdef CONFIG_X86_32
  41 # define FIX_EFLAGS     (__FIX_EFLAGS | X86_EFLAGS_RF)
  42 #else
  43 # define FIX_EFLAGS     __FIX_EFLAGS
  44 #endif
  45
  46 #define COPY(x)                 do {                    \
  47         get_user_ex(regs->x, &sc->x);                   \
  48 } while (0)
  49
  50 #define GET_SEG(seg)            ({                      \
  51         unsigned short tmp;                             \
  52         get_user_ex(tmp, &sc->seg);                     \
  53         tmp;                                            \
  54 })
  55
  56 #define COPY_SEG(seg)           do {                    \
  57         regs->seg = GET_SEG(seg);                       \
  58 } while (0)
  59
  60 #define COPY_SEG_CPL3(seg)      do {                    \
  61         regs->seg = GET_SEG(seg) | 3;                   \
  62 } while (0)
  63
  64 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  65                        unsigned long *pax)
  66 {
  67         void __user *buf;
  68         unsigned int tmpflags;
  69         unsigned int err = 0;
  70
  71         /* Always make any pending restarted system calls return -EINTR */
  72         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  73
  74         get_user_try {
  75
  76 #ifdef CONFIG_X86_32
  77                 set_user_gs(regs, GET_SEG(gs));
  78                 COPY_SEG(fs);
  79                 COPY_SEG(es);
  80                 COPY_SEG(ds);
  81 #endif /* CONFIG_X86_32 */
  82
  83                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  84                 COPY(dx); COPY(cx); COPY(ip);
  85
  86 #ifdef CONFIG_X86_64
  87                 COPY(r8);
  88                 COPY(r9);
  89                 COPY(r10);
  90                 COPY(r11);
  91                 COPY(r12);
  92                 COPY(r13);
  93                 COPY(r14);
  94                 COPY(r15);
  95 #endif /* CONFIG_X86_64 */
  96
  97 #ifdef CONFIG_X86_32
  98                 COPY_SEG_CPL3(cs);
  99                 COPY_SEG_CPL3(ss);
 100 #else /* !CONFIG_X86_32 */
 101                 /* Kernel saves and restores only the CS segment register on signals,
 102                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 103                  * App's signal handler can save/restore other segments if needed. */
 104                 COPY_SEG_CPL3(cs);
 105 #endif /* CONFIG_X86_32 */
 106
 107                 get_user_ex(tmpflags, &sc->flags);
 108                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 109                 regs->orig_ax = -1;             /* disable syscall checks */
 110
 111                 get_user_ex(buf, &sc->fpstate);
 112                 err |= restore_i387_xstate(buf);
 113
 114                 get_user_ex(*pax, &sc->ax);
 115         } get_user_catch(err);
 116
 117         return err;
 118 }
 119
 120 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 121                      struct pt_regs *regs, unsigned long mask)
 122 {
 123         int err = 0;
 124
 125         put_user_try {
 126
 127 #ifdef CONFIG_X86_32
 128                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 129                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 130                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 131                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 132 #endif /* CONFIG_X86_32 */
 133
 134                 put_user_ex(regs->di, &sc->di);
 135                 put_user_ex(regs->si, &sc->si);
 136                 put_user_ex(regs->bp, &sc->bp);
 137                 put_user_ex(regs->sp, &sc->sp);
 138                 put_user_ex(regs->bx, &sc->bx);
 139                 put_user_ex(regs->dx, &sc->dx);
 140                 put_user_ex(regs->cx, &sc->cx);
 141                 put_user_ex(regs->ax, &sc->ax);
 142 #ifdef CONFIG_X86_64
 143                 put_user_ex(regs->r8, &sc->r8);
 144                 put_user_ex(regs->r9, &sc->r9);
 145                 put_user_ex(regs->r10, &sc->r10);
 146                 put_user_ex(regs->r11, &sc->r11);
 147                 put_user_ex(regs->r12, &sc->r12);
 148                 put_user_ex(regs->r13, &sc->r13);
 149                 put_user_ex(regs->r14, &sc->r14);
 150                 put_user_ex(regs->r15, &sc->r15);
 151 #endif /* CONFIG_X86_64 */
 152
 153                 put_user_ex(current->thread.trap_nr, &sc->trapno);
 154                 put_user_ex(current->thread.error_code, &sc->err);
 155                 put_user_ex(regs->ip, &sc->ip);
 156 #ifdef CONFIG_X86_32
 157                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 158                 put_user_ex(regs->flags, &sc->flags);
 159                 put_user_ex(regs->sp, &sc->sp_at_signal);
 160                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 161 #else /* !CONFIG_X86_32 */
 162                 put_user_ex(regs->flags, &sc->flags);
 163                 put_user_ex(regs->cs, &sc->cs);
 164                 put_user_ex(0, &sc->gs);
 165                 put_user_ex(0, &sc->fs);
 166 #endif /* CONFIG_X86_32 */
 167
 168                 put_user_ex(fpstate, &sc->fpstate);
 169
 170                 /* non-iBCS2 extensions.. */
 171                 put_user_ex(mask, &sc->oldmask);
 172                 put_user_ex(current->thread.cr2, &sc->cr2);
 173         } put_user_catch(err);
 174
 175         return err;
 176 }
 177
 178 /*
 179  * Set up a signal frame.
 180  */
 181
 182 /*
 183  * Determine which stack to use..
 184  */
 185 static unsigned long align_sigframe(unsigned long sp)
 186 {
 187 #ifdef CONFIG_X86_32
 188         /*
 189          * Align the stack pointer according to the i386 ABI,
 190          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 191          */
 192         sp = ((sp + 4) & -16ul) - 4;
 193 #else /* !CONFIG_X86_32 */
 194         sp = round_down(sp, 16) - 8;
 195 #endif
 196         return sp;
 197 }
 198
 199 static inline void __user *
 200 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 201              void __user **fpstate)
 202 {
 203         /* Default to using normal stack */
 204         unsigned long sp = regs->sp;
 205         int onsigstack = on_sig_stack(sp);
 206
 207 #ifdef CONFIG_X86_64
 208         /* redzone */
 209         sp -= 128;
 210 #endif /* CONFIG_X86_64 */
 211
 212         if (!onsigstack) {
 213                 /* This is the X/Open sanctioned signal stack switching.  */
 214                 if (ka->sa.sa_flags & SA_ONSTACK) {
 215                         if (current->sas_ss_size)
 216                                 sp = current->sas_ss_sp + current->sas_ss_size;
 217                 } else {
 218 #ifdef CONFIG_X86_32
 219                         /* This is the legacy signal stack switching. */
 220                         if ((regs->ss & 0xffff) != __USER_DS &&
 221                                 !(ka->sa.sa_flags & SA_RESTORER) &&
 222                                         ka->sa.sa_restorer)
 223                                 sp = (unsigned long) ka->sa.sa_restorer;
 224 #endif /* CONFIG_X86_32 */
 225                 }
 226         }
 227
 228         if (used_math()) {
 229                 sp -= sig_xstate_size;
 230 #ifdef CONFIG_X86_64
 231                 sp = round_down(sp, 64);
 232 #endif /* CONFIG_X86_64 */
 233                 *fpstate = (void __user *)sp;
 234         }
 235
 236         sp = align_sigframe(sp - frame_size);
 237
 238         /*
 239          * If we are on the alternate signal stack and would overflow it, don't.
 240          * Return an always-bogus address instead so we will die with SIGSEGV.
 241          */
 242         if (onsigstack && !likely(on_sig_stack(sp)))
 243                 return (void __user *)-1L;
 244
 245         /* save i387 state */
 246         if (used_math() && save_i387_xstate(*fpstate) < 0)
 247                 return (void __user *)-1L;
 248
 249         return (void __user *)sp;
 250 }
 251
 252 #ifdef CONFIG_X86_32
 253 static const struct {
 254         u16 poplmovl;
 255         u32 val;
 256         u16 int80;
 257 } __attribute__((packed)) retcode = {
 258         0xb858,         /* popl %eax; movl $..., %eax */
 259         __NR_sigreturn,
 260         0x80cd,         /* int $0x80 */
 261 };
 262
 263 static const struct {
 264         u8  movl;
 265         u32 val;
 266         u16 int80;
 267         u8  pad;
 268 } __attribute__((packed)) rt_retcode = {
 269         0xb8,           /* movl $..., %eax */
 270         __NR_rt_sigreturn,
 271         0x80cd,         /* int $0x80 */
 272         0
 273 };
 274
 275 static int
 276 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 277               struct pt_regs *regs)
 278 {
 279         struct sigframe __user *frame;
 280         void __user *restorer;
 281         int err = 0;
 282         void __user *fpstate = NULL;
 283
 284         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 285
 286         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 287                 return -EFAULT;
 288
 289         if (__put_user(sig, &frame->sig))
 290                 return -EFAULT;
 291
 292         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 293                 return -EFAULT;
 294
 295         if (_NSIG_WORDS > 1) {
 296                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 297                                    sizeof(frame->extramask)))
 298                         return -EFAULT;
 299         }
 300
 301         if (current->mm->context.vdso)
 302                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 303         else
 304                 restorer = &frame->retcode;
 305         if (ka->sa.sa_flags & SA_RESTORER)
 306                 restorer = ka->sa.sa_restorer;
 307
 308         /* Set up to return from userspace.  */
 309         err |= __put_user(restorer, &frame->pretcode);
 310
 311         /*
 312          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 313          *
 314          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 315          * reasons and because gdb uses it as a signature to notice
 316          * signal handler stack frames.
 317          */
 318         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 319
 320         if (err)
 321                 return -EFAULT;
 322
 323         /* Set up registers for signal handler */
 324         regs->sp = (unsigned long)frame;
 325         regs->ip = (unsigned long)ka->sa.sa_handler;
 326         regs->ax = (unsigned long)sig;
 327         regs->dx = 0;
 328         regs->cx = 0;
 329
 330         regs->ds = __USER_DS;
 331         regs->es = __USER_DS;
 332         regs->ss = __USER_DS;
 333         regs->cs = __USER_CS;
 334
 335         return 0;
 336 }
 337
 338 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 339                             sigset_t *set, struct pt_regs *regs)
 340 {
 341         struct rt_sigframe __user *frame;
 342         void __user *restorer;
 343         int err = 0;
 344         void __user *fpstate = NULL;
 345
 346         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 347
 348         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 349                 return -EFAULT;
 350
 351         put_user_try {
 352                 put_user_ex(sig, &frame->sig);
 353                 put_user_ex(&frame->info, &frame->pinfo);
 354                 put_user_ex(&frame->uc, &frame->puc);
 355                 err |= copy_siginfo_to_user(&frame->info, info);
 356
 357                 /* Create the ucontext.  */
 358                 if (cpu_has_xsave)
 359                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 360                 else
 361                         put_user_ex(0, &frame->uc.uc_flags);
 362                 put_user_ex(0, &frame->uc.uc_link);
 363                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 364                 put_user_ex(sas_ss_flags(regs->sp),
 365                             &frame->uc.uc_stack.ss_flags);
 366                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 367                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 368                                         regs, set->sig[0]);
 369                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 370
 371                 /* Set up to return from userspace.  */
 372                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 373                 if (ka->sa.sa_flags & SA_RESTORER)
 374                         restorer = ka->sa.sa_restorer;
 375                 put_user_ex(restorer, &frame->pretcode);
 376
 377                 /*
 378                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 379                  *
 380                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 381                  * reasons and because gdb uses it as a signature to notice
 382                  * signal handler stack frames.
 383                  */
 384                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 385         } put_user_catch(err);
 386
 387         if (err)
 388                 return -EFAULT;
 389
 390         /* Set up registers for signal handler */
 391         regs->sp = (unsigned long)frame;
 392         regs->ip = (unsigned long)ka->sa.sa_handler;
 393         regs->ax = (unsigned long)sig;
 394         regs->dx = (unsigned long)&frame->info;
 395         regs->cx = (unsigned long)&frame->uc;
 396
 397         regs->ds = __USER_DS;
 398         regs->es = __USER_DS;
 399         regs->ss = __USER_DS;
 400         regs->cs = __USER_CS;
 401
 402         return 0;
 403 }
 404 #else /* !CONFIG_X86_32 */
 405 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 406                             sigset_t *set, struct pt_regs *regs)
 407 {
 408         struct rt_sigframe __user *frame;
 409         void __user *fp = NULL;
 410         int err = 0;
 411         struct task_struct *me = current;
 412
 413         frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
 414
 415         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 416                 return -EFAULT;
 417
 418         if (ka->sa.sa_flags & SA_SIGINFO) {
 419                 if (copy_siginfo_to_user(&frame->info, info))
 420                         return -EFAULT;
 421         }
 422
 423         put_user_try {
 424                 /* Create the ucontext.  */
 425                 if (cpu_has_xsave)
 426                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 427                 else
 428                         put_user_ex(0, &frame->uc.uc_flags);
 429                 put_user_ex(0, &frame->uc.uc_link);
 430                 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 431                 put_user_ex(sas_ss_flags(regs->sp),
 432                             &frame->uc.uc_stack.ss_flags);
 433                 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 434                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 435                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 436
 437                 /* Set up to return from userspace.  If provided, use a stub
 438                    already in userspace.  */
 439                 /* x86-64 should always use SA_RESTORER. */
 440                 if (ka->sa.sa_flags & SA_RESTORER) {
 441                         put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 442                 } else {
 443                         /* could use a vstub here */
 444                         err |= -EFAULT;
 445                 }
 446         } put_user_catch(err);
 447
 448         if (err)
 449                 return -EFAULT;
 450
 451         /* Set up registers for signal handler */
 452         regs->di = sig;
 453         /* In case the signal handler was declared without prototypes */
 454         regs->ax = 0;
 455
 456         /* This also works for non SA_SIGINFO handlers because they expect the
 457            next argument after the signal number on the stack. */
 458         regs->si = (unsigned long)&frame->info;
 459         regs->dx = (unsigned long)&frame->uc;
 460         regs->ip = (unsigned long) ka->sa.sa_handler;
 461
 462         regs->sp = (unsigned long)frame;
 463
 464         /* Set up the CS register to run signal handlers in 64-bit mode,
 465            even if the handler happens to be interrupting 32-bit code. */
 466         regs->cs = __USER_CS;
 467
 468         return 0;
 469 }
 470 #endif /* CONFIG_X86_32 */
 471
 472 #ifdef CONFIG_X86_32
 473 /*
 474  * Atomically swap in the new signal mask, and wait for a signal.
 475  */
 476 asmlinkage int
 477 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 478 {
 479         sigset_t blocked;
 480
 481         current->saved_sigmask = current->blocked;
 482
 483         mask &= _BLOCKABLE;
 484         siginitset(&blocked, mask);
 485         set_current_blocked(&blocked);
 486
 487         current->state = TASK_INTERRUPTIBLE;
 488         schedule();
 489
 490         set_restore_sigmask();
 491         return -ERESTARTNOHAND;
 492 }
 493
 494 asmlinkage int
 495 sys_sigaction(int sig, const struct old_sigaction __user *act,
 496               struct old_sigaction __user *oact)
 497 {
 498         struct k_sigaction new_ka, old_ka;
 499         int ret = 0;
 500
 501         if (act) {
 502                 old_sigset_t mask;
 503
 504                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 505                         return -EFAULT;
 506
 507                 get_user_try {
 508                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 509                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 510                         get_user_ex(mask, &act->sa_mask);
 511                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 512                 } get_user_catch(ret);
 513
 514                 if (ret)
 515                         return -EFAULT;
 516                 siginitset(&new_ka.sa.sa_mask, mask);
 517         }
 518
 519         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 520
 521         if (!ret && oact) {
 522                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 523                         return -EFAULT;
 524
 525                 put_user_try {
 526                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 527                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 528                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 529                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 530                 } put_user_catch(ret);
 531
 532                 if (ret)
 533                         return -EFAULT;
 534         }
 535
 536         return ret;
 537 }
 538 #endif /* CONFIG_X86_32 */
 539
 540 long
 541 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 542                 struct pt_regs *regs)
 543 {
 544         return do_sigaltstack(uss, uoss, regs->sp);
 545 }
 546
 547 /*
 548  * Do a signal return; undo the signal stack.
 549  */
 550 #ifdef CONFIG_X86_32
 551 unsigned long sys_sigreturn(struct pt_regs *regs)
 552 {
 553         struct sigframe __user *frame;
 554         unsigned long ax;
 555         sigset_t set;
 556
 557         frame = (struct sigframe __user *)(regs->sp - 8);
 558
 559         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 560                 goto badframe;
 561         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 562                 && __copy_from_user(&set.sig[1], &frame->extramask,
 563                                     sizeof(frame->extramask))))
 564                 goto badframe;
 565
 566         sigdelsetmask(&set, ~_BLOCKABLE);
 567         set_current_blocked(&set);
 568
 569         if (restore_sigcontext(regs, &frame->sc, &ax))
 570                 goto badframe;
 571         return ax;
 572
 573 badframe:
 574         signal_fault(regs, frame, "sigreturn");
 575
 576         return 0;
 577 }
 578 #endif /* CONFIG_X86_32 */
 579
 580 long sys_rt_sigreturn(struct pt_regs *regs)
 581 {
 582         struct rt_sigframe __user *frame;
 583         unsigned long ax;
 584         sigset_t set;
 585
 586         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 587         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 588                 goto badframe;
 589         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 590                 goto badframe;
 591
 592         sigdelsetmask(&set, ~_BLOCKABLE);
 593         set_current_blocked(&set);
 594
 595         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 596                 goto badframe;
 597
 598         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 599                 goto badframe;
 600
 601         return ax;
 602
 603 badframe:
 604         signal_fault(regs, frame, "rt_sigreturn");
 605         return 0;
 606 }
 607
 608 /*
 609  * OK, we're invoking a handler:
 610  */
 611 static int signr_convert(int sig)
 612 {
 613 #ifdef CONFIG_X86_32
 614         struct thread_info *info = current_thread_info();
 615
 616         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 617                 return info->exec_domain->signal_invmap[sig];
 618 #endif /* CONFIG_X86_32 */
 619         return sig;
 620 }
 621
 622 #ifdef CONFIG_X86_32
 623
 624 #define is_ia32 1
 625 #define ia32_setup_frame        __setup_frame
 626 #define ia32_setup_rt_frame     __setup_rt_frame
 627
 628 #else /* !CONFIG_X86_32 */
 629
 630 #ifdef CONFIG_IA32_EMULATION
 631 #define is_ia32 test_thread_flag(TIF_IA32)
 632 #else /* !CONFIG_IA32_EMULATION */
 633 #define is_ia32 0
 634 #endif /* CONFIG_IA32_EMULATION */
 635
 636 #ifdef CONFIG_X86_X32_ABI
 637 #define is_x32  test_thread_flag(TIF_X32)
 638
 639 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 640                               siginfo_t *info, compat_sigset_t *set,
 641                               struct pt_regs *regs);
 642 #else /* !CONFIG_X86_X32_ABI */
 643 #define is_x32  0
 644 #endif /* CONFIG_X86_X32_ABI */
 645
 646 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 647                 sigset_t *set, struct pt_regs *regs);
 648 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 649                 sigset_t *set, struct pt_regs *regs);
 650
 651 #endif /* CONFIG_X86_32 */
 652
 653 static int
 654 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 655                 struct pt_regs *regs)
 656 {
 657         int usig = signr_convert(sig);
 658         sigset_t *set = &current->blocked;
 659         int ret;
 660
 661         if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 662                 set = &current->saved_sigmask;
 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 #ifdef CONFIG_X86_X32_ABI
 671         } else if (is_x32) {
 672                 ret = x32_setup_rt_frame(usig, ka, info,
 673                                          (compat_sigset_t *)set, regs);
 674 #endif
 675         } else {
 676                 ret = __setup_rt_frame(sig, ka, info, set, regs);
 677         }
 678
 679         if (ret) {
 680                 force_sigsegv(sig, current);
 681                 return -EFAULT;
 682         }
 683
 684         current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 685         return ret;
 686 }
 687
 688 static int
 689 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 690                 struct pt_regs *regs)
 691 {
 692         int ret;
 693
 694         /* Are we from a system call? */
 695         if (syscall_get_nr(current, regs) >= 0) {
 696                 /* If so, check system call restarting.. */
 697                 switch (syscall_get_error(current, regs)) {
 698                 case -ERESTART_RESTARTBLOCK:
 699                 case -ERESTARTNOHAND:
 700                         regs->ax = -EINTR;
 701                         break;
 702
 703                 case -ERESTARTSYS:
 704                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 705                                 regs->ax = -EINTR;
 706                                 break;
 707                         }
 708                 /* fallthrough */
 709                 case -ERESTARTNOINTR:
 710                         regs->ax = regs->orig_ax;
 711                         regs->ip -= 2;
 712                         break;
 713                 }
 714         }
 715
 716         /*
 717          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 718          * flag so that register information in the sigcontext is correct.
 719          */
 720         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 721             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 722                 regs->flags &= ~X86_EFLAGS_TF;
 723
 724         ret = setup_rt_frame(sig, ka, info, regs);
 725
 726         if (ret)
 727                 return ret;
 728
 729         /*
 730          * Clear the direction flag as per the ABI for function entry.
 731          */
 732         regs->flags &= ~X86_EFLAGS_DF;
 733
 734         /*
 735          * Clear TF when entering the signal handler, but
 736          * notify any tracer that was single-stepping it.
 737          * The tracer may want to single-step inside the
 738          * handler too.
 739          */
 740         regs->flags &= ~X86_EFLAGS_TF;
 741
 742         block_sigmask(ka, sig);
 743
 744         tracehook_signal_handler(sig, info, ka, regs,
 745                                  test_thread_flag(TIF_SINGLESTEP));
 746
 747         return 0;
 748 }
 749
 750 #ifdef CONFIG_X86_32
 751 #define NR_restart_syscall      __NR_restart_syscall
 752 #else /* !CONFIG_X86_32 */
 753 #define NR_restart_syscall      \
 754         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 755 #endif /* CONFIG_X86_32 */
 756
 757 /*
 758  * Note that 'init' is a special process: it doesn't get signals it doesn't
 759  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 760  * mistake.
 761  */
 762 static void do_signal(struct pt_regs *regs)
 763 {
 764         struct k_sigaction ka;
 765         siginfo_t info;
 766         int signr;
 767
 768         /*
 769          * We want the common case to go fast, which is why we may in certain
 770          * cases get here from kernel mode. Just return without doing anything
 771          * if so.
 772          * X86_32: vm86 regs switched out by assembly code before reaching
 773          * here, so testing against kernel CS suffices.
 774          */
 775         if (!user_mode(regs))
 776                 return;
 777
 778         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 779         if (signr > 0) {
 780                 /* Whee! Actually deliver the signal.  */
 781                 handle_signal(signr, &info, &ka, regs);
 782                 return;
 783         }
 784
 785         /* Did we come from a system call? */
 786         if (syscall_get_nr(current, regs) >= 0) {
 787                 /* Restart the system call - no handlers present */
 788                 switch (syscall_get_error(current, regs)) {
 789                 case -ERESTARTNOHAND:
 790                 case -ERESTARTSYS:
 791                 case -ERESTARTNOINTR:
 792                         regs->ax = regs->orig_ax;
 793                         regs->ip -= 2;
 794                         break;
 795
 796                 case -ERESTART_RESTARTBLOCK:
 797                         regs->ax = NR_restart_syscall;
 798                         regs->ip -= 2;
 799                         break;
 800                 }
 801         }
 802
 803         /*
 804          * If there's no signal to deliver, we just put the saved sigmask
 805          * back.
 806          */
 807         if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 808                 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 809                 set_current_blocked(&current->saved_sigmask);
 810         }
 811 }
 812
 813 /*
 814  * notification of userspace execution resumption
 815  * - triggered by the TIF_WORK_MASK flags
 816  */
 817 void
 818 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 819 {
 820 #ifdef CONFIG_X86_MCE
 821         /* notify userspace of pending MCEs */
 822         if (thread_info_flags & _TIF_MCE_NOTIFY)
 823                 mce_notify_process();
 824 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 825
 826         /* deal with pending signal delivery */
 827         if (thread_info_flags & _TIF_SIGPENDING)
 828                 do_signal(regs);
 829
 830         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 831                 clear_thread_flag(TIF_NOTIFY_RESUME);
 832                 tracehook_notify_resume(regs);
 833                 if (current->replacement_session_keyring)
 834                         key_replace_session_keyring();
 835         }
 836         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 837                 fire_user_return_notifiers();
 838
 839 #ifdef CONFIG_X86_32
 840         clear_thread_flag(TIF_IRET);
 841 #endif /* CONFIG_X86_32 */
 842 }
 843
 844 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 845 {
 846         struct task_struct *me = current;
 847
 848         if (show_unhandled_signals && printk_ratelimit()) {
 849                 printk("%s"
 850                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 851                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 852                        me->comm, me->pid, where, frame,
 853                        regs->ip, regs->sp, regs->orig_ax);
 854                 print_vma_addr(" in ", regs->ip);
 855                 printk(KERN_CONT "\n");
 856         }
 857
 858         force_sig(SIGSEGV, me);
 859 }
 860
 861 #ifdef CONFIG_X86_X32_ABI
 862 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 863                               siginfo_t *info, compat_sigset_t *set,
 864                               struct pt_regs *regs)
 865 {
 866         struct rt_sigframe_x32 __user *frame;
 867         void __user *restorer;
 868         int err = 0;
 869         void __user *fpstate = NULL;
 870
 871         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 872
 873         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 874                 return -EFAULT;
 875
 876         if (ka->sa.sa_flags & SA_SIGINFO) {
 877                 if (copy_siginfo_to_user32(&frame->info, info))
 878                         return -EFAULT;
 879         }
 880
 881         put_user_try {
 882                 /* Create the ucontext.  */
 883                 if (cpu_has_xsave)
 884                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 885                 else
 886                         put_user_ex(0, &frame->uc.uc_flags);
 887                 put_user_ex(0, &frame->uc.uc_link);
 888                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 889                 put_user_ex(sas_ss_flags(regs->sp),
 890                             &frame->uc.uc_stack.ss_flags);
 891                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 892                 put_user_ex(0, &frame->uc.uc__pad0);
 893                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 894                                         regs, set->sig[0]);
 895                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 896
 897                 if (ka->sa.sa_flags & SA_RESTORER) {
 898                         restorer = ka->sa.sa_restorer;
 899                 } else {
 900                         /* could use a vstub here */
 901                         restorer = NULL;
 902                         err |= -EFAULT;
 903                 }
 904                 put_user_ex(restorer, &frame->pretcode);
 905         } put_user_catch(err);
 906
 907         if (err)
 908                 return -EFAULT;
 909
 910         /* Set up registers for signal handler */
 911         regs->sp = (unsigned long) frame;
 912         regs->ip = (unsigned long) ka->sa.sa_handler;
 913
 914         /* We use the x32 calling convention here... */
 915         regs->di = sig;
 916         regs->si = (unsigned long) &frame->info;
 917         regs->dx = (unsigned long) &frame->uc;
 918
 919         loadsegment(ds, __USER_DS);
 920         loadsegment(es, __USER_DS);
 921
 922         regs->cs = __USER_CS;
 923         regs->ss = __USER_DS;
 924
 925         return 0;
 926 }
 927
 928 asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)
 929 {
 930         struct rt_sigframe_x32 __user *frame;
 931         sigset_t set;
 932         unsigned long ax;
 933         struct pt_regs tregs;
 934
 935         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 936
 937         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 938                 goto badframe;
 939         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 940                 goto badframe;
 941
 942         sigdelsetmask(&set, ~_BLOCKABLE);
 943         set_current_blocked(&set);
 944
 945         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 946                 goto badframe;
 947
 948         tregs = *regs;
 949         if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
 950                 goto badframe;
 951
 952         return ax;
 953
 954 badframe:
 955         signal_fault(regs, frame, "x32 rt_sigreturn");
 956         return 0;
 957 }
 958 #endif