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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/smp.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.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 #include <linux/user-return-notifier.h>
  24 #include <linux/uprobes.h>
  25 #include <linux/context_tracking.h>
  26
  27 #include <asm/processor.h>
  28 #include <asm/ucontext.h>
  29 #include <asm/i387.h>
  30 #include <asm/fpu-internal.h>
  31 #include <asm/vdso.h>
  32 #include <asm/mce.h>
  33 #include <asm/sighandling.h>
  34
  35 #ifdef CONFIG_X86_64
  36 #include <asm/proto.h>
  37 #include <asm/ia32_unistd.h>
  38 #include <asm/sys_ia32.h>
  39 #endif /* CONFIG_X86_64 */
  40
  41 #include <asm/syscall.h>
  42 #include <asm/syscalls.h>
  43
  44 #include <asm/sigframe.h>
  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 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  71                        unsigned long *pax)
  72 {
  73         void __user *buf;
  74         unsigned int tmpflags;
  75         unsigned int err = 0;
  76
  77         /* Always make any pending restarted system calls return -EINTR */
  78         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  79
  80         get_user_try {
  81
  82 #ifdef CONFIG_X86_32
  83                 set_user_gs(regs, GET_SEG(gs));
  84                 COPY_SEG(fs);
  85                 COPY_SEG(es);
  86                 COPY_SEG(ds);
  87 #endif /* CONFIG_X86_32 */
  88
  89                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  90                 COPY(dx); COPY(cx); COPY(ip);
  91
  92 #ifdef CONFIG_X86_64
  93                 COPY(r8);
  94                 COPY(r9);
  95                 COPY(r10);
  96                 COPY(r11);
  97                 COPY(r12);
  98                 COPY(r13);
  99                 COPY(r14);
 100                 COPY(r15);
 101 #endif /* CONFIG_X86_64 */
 102
 103 #ifdef CONFIG_X86_32
 104                 COPY_SEG_CPL3(cs);
 105                 COPY_SEG_CPL3(ss);
 106 #else /* !CONFIG_X86_32 */
 107                 /* Kernel saves and restores only the CS segment register on signals,
 108                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 109                  * App's signal handler can save/restore other segments if needed. */
 110                 COPY_SEG_CPL3(cs);
 111 #endif /* CONFIG_X86_32 */
 112
 113                 get_user_ex(tmpflags, &sc->flags);
 114                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 115                 regs->orig_ax = -1;             /* disable syscall checks */
 116
 117                 get_user_ex(buf, &sc->fpstate);
 118
 119                 get_user_ex(*pax, &sc->ax);
 120         } get_user_catch(err);
 121
 122         err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
 123
 124         return err;
 125 }
 126
 127 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 128                      struct pt_regs *regs, unsigned long mask)
 129 {
 130         int err = 0;
 131
 132         put_user_try {
 133
 134 #ifdef CONFIG_X86_32
 135                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 136                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 137                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 138                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 139 #endif /* CONFIG_X86_32 */
 140
 141                 put_user_ex(regs->di, &sc->di);
 142                 put_user_ex(regs->si, &sc->si);
 143                 put_user_ex(regs->bp, &sc->bp);
 144                 put_user_ex(regs->sp, &sc->sp);
 145                 put_user_ex(regs->bx, &sc->bx);
 146                 put_user_ex(regs->dx, &sc->dx);
 147                 put_user_ex(regs->cx, &sc->cx);
 148                 put_user_ex(regs->ax, &sc->ax);
 149 #ifdef CONFIG_X86_64
 150                 put_user_ex(regs->r8, &sc->r8);
 151                 put_user_ex(regs->r9, &sc->r9);
 152                 put_user_ex(regs->r10, &sc->r10);
 153                 put_user_ex(regs->r11, &sc->r11);
 154                 put_user_ex(regs->r12, &sc->r12);
 155                 put_user_ex(regs->r13, &sc->r13);
 156                 put_user_ex(regs->r14, &sc->r14);
 157                 put_user_ex(regs->r15, &sc->r15);
 158 #endif /* CONFIG_X86_64 */
 159
 160                 put_user_ex(current->thread.trap_nr, &sc->trapno);
 161                 put_user_ex(current->thread.error_code, &sc->err);
 162                 put_user_ex(regs->ip, &sc->ip);
 163 #ifdef CONFIG_X86_32
 164                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 165                 put_user_ex(regs->flags, &sc->flags);
 166                 put_user_ex(regs->sp, &sc->sp_at_signal);
 167                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 168 #else /* !CONFIG_X86_32 */
 169                 put_user_ex(regs->flags, &sc->flags);
 170                 put_user_ex(regs->cs, &sc->cs);
 171                 put_user_ex(0, &sc->gs);
 172                 put_user_ex(0, &sc->fs);
 173 #endif /* CONFIG_X86_32 */
 174
 175                 put_user_ex(fpstate, &sc->fpstate);
 176
 177                 /* non-iBCS2 extensions.. */
 178                 put_user_ex(mask, &sc->oldmask);
 179                 put_user_ex(current->thread.cr2, &sc->cr2);
 180         } put_user_catch(err);
 181
 182         return err;
 183 }
 184
 185 /*
 186  * Set up a signal frame.
 187  */
 188
 189 /*
 190  * Determine which stack to use..
 191  */
 192 static unsigned long align_sigframe(unsigned long sp)
 193 {
 194 #ifdef CONFIG_X86_32
 195         /*
 196          * Align the stack pointer according to the i386 ABI,
 197          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 198          */
 199         sp = ((sp + 4) & -16ul) - 4;
 200 #else /* !CONFIG_X86_32 */
 201         sp = round_down(sp, 16) - 8;
 202 #endif
 203         return sp;
 204 }
 205
 206 static inline void __user *
 207 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 208              void __user **fpstate)
 209 {
 210         /* Default to using normal stack */
 211         unsigned long math_size = 0;
 212         unsigned long sp = regs->sp;
 213         unsigned long buf_fx = 0;
 214         int onsigstack = on_sig_stack(sp);
 215
 216         /* redzone */
 217         if (config_enabled(CONFIG_X86_64))
 218                 sp -= 128;
 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 if (config_enabled(CONFIG_X86_32) &&
 226                            (regs->ss & 0xffff) != __USER_DS &&
 227                            !(ka->sa.sa_flags & SA_RESTORER) &&
 228                            ka->sa.sa_restorer) {
 229                                 /* This is the legacy signal stack switching. */
 230                                 sp = (unsigned long) ka->sa.sa_restorer;
 231                 }
 232         }
 233
 234         if (used_math()) {
 235                 sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
 236                                      &buf_fx, &math_size);
 237                 *fpstate = (void __user *)sp;
 238         }
 239
 240         sp = align_sigframe(sp - frame_size);
 241
 242         /*
 243          * If we are on the alternate signal stack and would overflow it, don't.
 244          * Return an always-bogus address instead so we will die with SIGSEGV.
 245          */
 246         if (onsigstack && !likely(on_sig_stack(sp)))
 247                 return (void __user *)-1L;
 248
 249         /* save i387 and extended state */
 250         if (used_math() &&
 251             save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
 252                 return (void __user *)-1L;
 253
 254         return (void __user *)sp;
 255 }
 256
 257 #ifdef CONFIG_X86_32
 258 static const struct {
 259         u16 poplmovl;
 260         u32 val;
 261         u16 int80;
 262 } __attribute__((packed)) retcode = {
 263         0xb858,         /* popl %eax; movl $..., %eax */
 264         __NR_sigreturn,
 265         0x80cd,         /* int $0x80 */
 266 };
 267
 268 static const struct {
 269         u8  movl;
 270         u32 val;
 271         u16 int80;
 272         u8  pad;
 273 } __attribute__((packed)) rt_retcode = {
 274         0xb8,           /* movl $..., %eax */
 275         __NR_rt_sigreturn,
 276         0x80cd,         /* int $0x80 */
 277         0
 278 };
 279
 280 static int
 281 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 282               struct pt_regs *regs)
 283 {
 284         struct sigframe __user *frame;
 285         void __user *restorer;
 286         int err = 0;
 287         void __user *fpstate = NULL;
 288
 289         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 290
 291         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 292                 return -EFAULT;
 293
 294         if (__put_user(sig, &frame->sig))
 295                 return -EFAULT;
 296
 297         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 298                 return -EFAULT;
 299
 300         if (_NSIG_WORDS > 1) {
 301                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 302                                    sizeof(frame->extramask)))
 303                         return -EFAULT;
 304         }
 305
 306         if (current->mm->context.vdso)
 307                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 308         else
 309                 restorer = &frame->retcode;
 310         if (ka->sa.sa_flags & SA_RESTORER)
 311                 restorer = ka->sa.sa_restorer;
 312
 313         /* Set up to return from userspace.  */
 314         err |= __put_user(restorer, &frame->pretcode);
 315
 316         /*
 317          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 318          *
 319          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 320          * reasons and because gdb uses it as a signature to notice
 321          * signal handler stack frames.
 322          */
 323         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 324
 325         if (err)
 326                 return -EFAULT;
 327
 328         /* Set up registers for signal handler */
 329         regs->sp = (unsigned long)frame;
 330         regs->ip = (unsigned long)ka->sa.sa_handler;
 331         regs->ax = (unsigned long)sig;
 332         regs->dx = 0;
 333         regs->cx = 0;
 334
 335         regs->ds = __USER_DS;
 336         regs->es = __USER_DS;
 337         regs->ss = __USER_DS;
 338         regs->cs = __USER_CS;
 339
 340         return 0;
 341 }
 342
 343 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 344                             sigset_t *set, struct pt_regs *regs)
 345 {
 346         struct rt_sigframe __user *frame;
 347         void __user *restorer;
 348         int err = 0;
 349         void __user *fpstate = NULL;
 350
 351         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 352
 353         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 354                 return -EFAULT;
 355
 356         put_user_try {
 357                 put_user_ex(sig, &frame->sig);
 358                 put_user_ex(&frame->info, &frame->pinfo);
 359                 put_user_ex(&frame->uc, &frame->puc);
 360
 361                 /* Create the ucontext.  */
 362                 if (cpu_has_xsave)
 363                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 364                 else
 365                         put_user_ex(0, &frame->uc.uc_flags);
 366                 put_user_ex(0, &frame->uc.uc_link);
 367                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 368                 put_user_ex(sas_ss_flags(regs->sp),
 369                             &frame->uc.uc_stack.ss_flags);
 370                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 371
 372                 /* Set up to return from userspace.  */
 373                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 374                 if (ka->sa.sa_flags & SA_RESTORER)
 375                         restorer = ka->sa.sa_restorer;
 376                 put_user_ex(restorer, &frame->pretcode);
 377
 378                 /*
 379                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 380                  *
 381                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 382                  * reasons and because gdb uses it as a signature to notice
 383                  * signal handler stack frames.
 384                  */
 385                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 386         } put_user_catch(err);
 387
 388         err |= copy_siginfo_to_user(&frame->info, info);
 389         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 390                                 regs, set->sig[0]);
 391         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 392
 393         if (err)
 394                 return -EFAULT;
 395
 396         /* Set up registers for signal handler */
 397         regs->sp = (unsigned long)frame;
 398         regs->ip = (unsigned long)ka->sa.sa_handler;
 399         regs->ax = (unsigned long)sig;
 400         regs->dx = (unsigned long)&frame->info;
 401         regs->cx = (unsigned long)&frame->uc;
 402
 403         regs->ds = __USER_DS;
 404         regs->es = __USER_DS;
 405         regs->ss = __USER_DS;
 406         regs->cs = __USER_CS;
 407
 408         return 0;
 409 }
 410 #else /* !CONFIG_X86_32 */
 411 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 412                             sigset_t *set, struct pt_regs *regs)
 413 {
 414         struct rt_sigframe __user *frame;
 415         void __user *fp = NULL;
 416         int err = 0;
 417         struct task_struct *me = current;
 418
 419         frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
 420
 421         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 422                 return -EFAULT;
 423
 424         if (ka->sa.sa_flags & SA_SIGINFO) {
 425                 if (copy_siginfo_to_user(&frame->info, info))
 426                         return -EFAULT;
 427         }
 428
 429         put_user_try {
 430                 /* Create the ucontext.  */
 431                 if (cpu_has_xsave)
 432                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 433                 else
 434                         put_user_ex(0, &frame->uc.uc_flags);
 435                 put_user_ex(0, &frame->uc.uc_link);
 436                 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 437                 put_user_ex(sas_ss_flags(regs->sp),
 438                             &frame->uc.uc_stack.ss_flags);
 439                 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 440
 441                 /* Set up to return from userspace.  If provided, use a stub
 442                    already in userspace.  */
 443                 /* x86-64 should always use SA_RESTORER. */
 444                 if (ka->sa.sa_flags & SA_RESTORER) {
 445                         put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 446                 } else {
 447                         /* could use a vstub here */
 448                         err |= -EFAULT;
 449                 }
 450         } put_user_catch(err);
 451
 452         err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 453         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 454
 455         if (err)
 456                 return -EFAULT;
 457
 458         /* Set up registers for signal handler */
 459         regs->di = sig;
 460         /* In case the signal handler was declared without prototypes */
 461         regs->ax = 0;
 462
 463         /* This also works for non SA_SIGINFO handlers because they expect the
 464            next argument after the signal number on the stack. */
 465         regs->si = (unsigned long)&frame->info;
 466         regs->dx = (unsigned long)&frame->uc;
 467         regs->ip = (unsigned long) ka->sa.sa_handler;
 468
 469         regs->sp = (unsigned long)frame;
 470
 471         /* Set up the CS register to run signal handlers in 64-bit mode,
 472            even if the handler happens to be interrupting 32-bit code. */
 473         regs->cs = __USER_CS;
 474
 475         return 0;
 476 }
 477 #endif /* CONFIG_X86_32 */
 478
 479 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 480                               siginfo_t *info, compat_sigset_t *set,
 481                               struct pt_regs *regs)
 482 {
 483 #ifdef CONFIG_X86_X32_ABI
 484         struct rt_sigframe_x32 __user *frame;
 485         void __user *restorer;
 486         int err = 0;
 487         void __user *fpstate = NULL;
 488
 489         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 490
 491         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 492                 return -EFAULT;
 493
 494         if (ka->sa.sa_flags & SA_SIGINFO) {
 495                 if (copy_siginfo_to_user32(&frame->info, info))
 496                         return -EFAULT;
 497         }
 498
 499         put_user_try {
 500                 /* Create the ucontext.  */
 501                 if (cpu_has_xsave)
 502                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 503                 else
 504                         put_user_ex(0, &frame->uc.uc_flags);
 505                 put_user_ex(0, &frame->uc.uc_link);
 506                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 507                 put_user_ex(sas_ss_flags(regs->sp),
 508                             &frame->uc.uc_stack.ss_flags);
 509                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 510                 put_user_ex(0, &frame->uc.uc__pad0);
 511
 512                 if (ka->sa.sa_flags & SA_RESTORER) {
 513                         restorer = ka->sa.sa_restorer;
 514                 } else {
 515                         /* could use a vstub here */
 516                         restorer = NULL;
 517                         err |= -EFAULT;
 518                 }
 519                 put_user_ex(restorer, &frame->pretcode);
 520         } put_user_catch(err);
 521
 522         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 523                                 regs, set->sig[0]);
 524         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 525
 526         if (err)
 527                 return -EFAULT;
 528
 529         /* Set up registers for signal handler */
 530         regs->sp = (unsigned long) frame;
 531         regs->ip = (unsigned long) ka->sa.sa_handler;
 532
 533         /* We use the x32 calling convention here... */
 534         regs->di = sig;
 535         regs->si = (unsigned long) &frame->info;
 536         regs->dx = (unsigned long) &frame->uc;
 537
 538         loadsegment(ds, __USER_DS);
 539         loadsegment(es, __USER_DS);
 540
 541         regs->cs = __USER_CS;
 542         regs->ss = __USER_DS;
 543 #endif  /* CONFIG_X86_X32_ABI */
 544
 545         return 0;
 546 }
 547
 548 #ifdef CONFIG_X86_32
 549 /*
 550  * Atomically swap in the new signal mask, and wait for a signal.
 551  */
 552 asmlinkage int
 553 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 554 {
 555         sigset_t blocked;
 556         siginitset(&blocked, mask);
 557         return sigsuspend(&blocked);
 558 }
 559
 560 asmlinkage int
 561 sys_sigaction(int sig, const struct old_sigaction __user *act,
 562               struct old_sigaction __user *oact)
 563 {
 564         struct k_sigaction new_ka, old_ka;
 565         int ret = 0;
 566
 567         if (act) {
 568                 old_sigset_t mask;
 569
 570                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 571                         return -EFAULT;
 572
 573                 get_user_try {
 574                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 575                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 576                         get_user_ex(mask, &act->sa_mask);
 577                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 578                 } get_user_catch(ret);
 579
 580                 if (ret)
 581                         return -EFAULT;
 582                 siginitset(&new_ka.sa.sa_mask, mask);
 583         }
 584
 585         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 586
 587         if (!ret && oact) {
 588                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 589                         return -EFAULT;
 590
 591                 put_user_try {
 592                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 593                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 594                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 595                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 596                 } put_user_catch(ret);
 597
 598                 if (ret)
 599                         return -EFAULT;
 600         }
 601
 602         return ret;
 603 }
 604 #endif /* CONFIG_X86_32 */
 605
 606 long
 607 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 608                 struct pt_regs *regs)
 609 {
 610         return do_sigaltstack(uss, uoss, regs->sp);
 611 }
 612
 613 /*
 614  * Do a signal return; undo the signal stack.
 615  */
 616 #ifdef CONFIG_X86_32
 617 unsigned long sys_sigreturn(struct pt_regs *regs)
 618 {
 619         struct sigframe __user *frame;
 620         unsigned long ax;
 621         sigset_t set;
 622
 623         frame = (struct sigframe __user *)(regs->sp - 8);
 624
 625         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 626                 goto badframe;
 627         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 628                 && __copy_from_user(&set.sig[1], &frame->extramask,
 629                                     sizeof(frame->extramask))))
 630                 goto badframe;
 631
 632         set_current_blocked(&set);
 633
 634         if (restore_sigcontext(regs, &frame->sc, &ax))
 635                 goto badframe;
 636         return ax;
 637
 638 badframe:
 639         signal_fault(regs, frame, "sigreturn");
 640
 641         return 0;
 642 }
 643 #endif /* CONFIG_X86_32 */
 644
 645 long sys_rt_sigreturn(struct pt_regs *regs)
 646 {
 647         struct rt_sigframe __user *frame;
 648         unsigned long ax;
 649         sigset_t set;
 650
 651         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 652         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 653                 goto badframe;
 654         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 655                 goto badframe;
 656
 657         set_current_blocked(&set);
 658
 659         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 660                 goto badframe;
 661
 662         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 663                 goto badframe;
 664
 665         return ax;
 666
 667 badframe:
 668         signal_fault(regs, frame, "rt_sigreturn");
 669         return 0;
 670 }
 671
 672 /*
 673  * OK, we're invoking a handler:
 674  */
 675 static int signr_convert(int sig)
 676 {
 677 #ifdef CONFIG_X86_32
 678         struct thread_info *info = current_thread_info();
 679
 680         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 681                 return info->exec_domain->signal_invmap[sig];
 682 #endif /* CONFIG_X86_32 */
 683         return sig;
 684 }
 685
 686 static int
 687 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 688                 struct pt_regs *regs)
 689 {
 690         int usig = signr_convert(sig);
 691         sigset_t *set = sigmask_to_save();
 692         compat_sigset_t *cset = (compat_sigset_t *) set;
 693
 694         /* Set up the stack frame */
 695         if (is_ia32_frame()) {
 696                 if (ka->sa.sa_flags & SA_SIGINFO)
 697                         return ia32_setup_rt_frame(usig, ka, info, cset, regs);
 698                 else
 699                         return ia32_setup_frame(usig, ka, cset, regs);
 700         } else if (is_x32_frame()) {
 701                 return x32_setup_rt_frame(usig, ka, info, cset, regs);
 702         } else {
 703                 return __setup_rt_frame(sig, ka, info, set, regs);
 704         }
 705 }
 706
 707 static void
 708 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 709                 struct pt_regs *regs)
 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         if (setup_rt_frame(sig, ka, info, regs) < 0) {
 742                 force_sigsegv(sig, current);
 743                 return;
 744         }
 745
 746         /*
 747          * Clear the direction flag as per the ABI for function entry.
 748          */
 749         regs->flags &= ~X86_EFLAGS_DF;
 750
 751         /*
 752          * Clear TF when entering the signal handler, but
 753          * notify any tracer that was single-stepping it.
 754          * The tracer may want to single-step inside the
 755          * handler too.
 756          */
 757         regs->flags &= ~X86_EFLAGS_TF;
 758
 759         signal_delivered(sig, info, ka, regs,
 760                          test_thread_flag(TIF_SINGLESTEP));
 761 }
 762
 763 #ifdef CONFIG_X86_32
 764 #define NR_restart_syscall      __NR_restart_syscall
 765 #else /* !CONFIG_X86_32 */
 766 #define NR_restart_syscall      \
 767         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 768 #endif /* CONFIG_X86_32 */
 769
 770 /*
 771  * Note that 'init' is a special process: it doesn't get signals it doesn't
 772  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 773  * mistake.
 774  */
 775 static void do_signal(struct pt_regs *regs)
 776 {
 777         struct k_sigaction ka;
 778         siginfo_t info;
 779         int signr;
 780
 781         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 782         if (signr > 0) {
 783                 /* Whee! Actually deliver the signal.  */
 784                 handle_signal(signr, &info, &ka, regs);
 785                 return;
 786         }
 787
 788         /* Did we come from a system call? */
 789         if (syscall_get_nr(current, regs) >= 0) {
 790                 /* Restart the system call - no handlers present */
 791                 switch (syscall_get_error(current, regs)) {
 792                 case -ERESTARTNOHAND:
 793                 case -ERESTARTSYS:
 794                 case -ERESTARTNOINTR:
 795                         regs->ax = regs->orig_ax;
 796                         regs->ip -= 2;
 797                         break;
 798
 799                 case -ERESTART_RESTARTBLOCK:
 800                         regs->ax = NR_restart_syscall;
 801                         regs->ip -= 2;
 802                         break;
 803                 }
 804         }
 805
 806         /*
 807          * If there's no signal to deliver, we just put the saved sigmask
 808          * back.
 809          */
 810         restore_saved_sigmask();
 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         user_exit();
 821
 822 #ifdef CONFIG_X86_MCE
 823         /* notify userspace of pending MCEs */
 824         if (thread_info_flags & _TIF_MCE_NOTIFY)
 825                 mce_notify_process();
 826 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 827
 828         if (thread_info_flags & _TIF_UPROBE)
 829                 uprobe_notify_resume(regs);
 830
 831         /* deal with pending signal delivery */
 832         if (thread_info_flags & _TIF_SIGPENDING)
 833                 do_signal(regs);
 834
 835         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 836                 clear_thread_flag(TIF_NOTIFY_RESUME);
 837                 tracehook_notify_resume(regs);
 838         }
 839         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 840                 fire_user_return_notifiers();
 841
 842         user_enter();
 843 }
 844
 845 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 846 {
 847         struct task_struct *me = current;
 848
 849         if (show_unhandled_signals && printk_ratelimit()) {
 850                 printk("%s"
 851                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 852                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 853                        me->comm, me->pid, where, frame,
 854                        regs->ip, regs->sp, regs->orig_ax);
 855                 print_vma_addr(" in ", regs->ip);
 856                 pr_cont("\n");
 857         }
 858
 859         force_sig(SIGSEGV, me);
 860 }
 861
 862 #ifdef CONFIG_X86_X32_ABI
 863 asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)
 864 {
 865         struct rt_sigframe_x32 __user *frame;
 866         sigset_t set;
 867         unsigned long ax;
 868         struct pt_regs tregs;
 869
 870         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 871
 872         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 873                 goto badframe;
 874         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 875                 goto badframe;
 876
 877         set_current_blocked(&set);
 878
 879         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 880                 goto badframe;
 881
 882         tregs = *regs;
 883         if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
 884                 goto badframe;
 885
 886         return ax;
 887
 888 badframe:
 889         signal_fault(regs, frame, "x32 rt_sigreturn");
 890         return 0;
 891 }
 892 #endif