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
  26 #include <asm/processor.h>
  27 #include <asm/ucontext.h>
  28 #include <asm/i387.h>
  29 #include <asm/fpu-internal.h>
  30 #include <asm/vdso.h>
  31 #include <asm/mce.h>
  32 #include <asm/sighandling.h>
  33
  34 #ifdef CONFIG_X86_64
  35 #include <asm/proto.h>
  36 #include <asm/ia32_unistd.h>
  37 #include <asm/sys_ia32.h>
  38 #endif /* CONFIG_X86_64 */
  39
  40 #include <asm/syscall.h>
  41 #include <asm/syscalls.h>
  42
  43 #include <asm/sigframe.h>
  44
  45 #ifdef CONFIG_X86_32
  46 # define FIX_EFLAGS     (__FIX_EFLAGS | X86_EFLAGS_RF)
  47 #else
  48 # define FIX_EFLAGS     __FIX_EFLAGS
  49 #endif
  50
  51 #define COPY(x)                 do {                    \
  52         get_user_ex(regs->x, &sc->x);                   \
  53 } while (0)
  54
  55 #define GET_SEG(seg)            ({                      \
  56         unsigned short tmp;                             \
  57         get_user_ex(tmp, &sc->seg);                     \
  58         tmp;                                            \
  59 })
  60
  61 #define COPY_SEG(seg)           do {                    \
  62         regs->seg = GET_SEG(seg);                       \
  63 } while (0)
  64
  65 #define COPY_SEG_CPL3(seg)      do {                    \
  66         regs->seg = GET_SEG(seg) | 3;                   \
  67 } while (0)
  68
  69 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
  70                        unsigned long *pax)
  71 {
  72         void __user *buf;
  73         unsigned int tmpflags;
  74         unsigned int err = 0;
  75
  76         /* Always make any pending restarted system calls return -EINTR */
  77         current_thread_info()->restart_block.fn = do_no_restart_syscall;
  78
  79         get_user_try {
  80
  81 #ifdef CONFIG_X86_32
  82                 set_user_gs(regs, GET_SEG(gs));
  83                 COPY_SEG(fs);
  84                 COPY_SEG(es);
  85                 COPY_SEG(ds);
  86 #endif /* CONFIG_X86_32 */
  87
  88                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  89                 COPY(dx); COPY(cx); COPY(ip);
  90
  91 #ifdef CONFIG_X86_64
  92                 COPY(r8);
  93                 COPY(r9);
  94                 COPY(r10);
  95                 COPY(r11);
  96                 COPY(r12);
  97                 COPY(r13);
  98                 COPY(r14);
  99                 COPY(r15);
 100 #endif /* CONFIG_X86_64 */
 101
 102 #ifdef CONFIG_X86_32
 103                 COPY_SEG_CPL3(cs);
 104                 COPY_SEG_CPL3(ss);
 105 #else /* !CONFIG_X86_32 */
 106                 /* Kernel saves and restores only the CS segment register on signals,
 107                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 108                  * App's signal handler can save/restore other segments if needed. */
 109                 COPY_SEG_CPL3(cs);
 110 #endif /* CONFIG_X86_32 */
 111
 112                 get_user_ex(tmpflags, &sc->flags);
 113                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 114                 regs->orig_ax = -1;             /* disable syscall checks */
 115
 116                 get_user_ex(buf, &sc->fpstate);
 117
 118                 get_user_ex(*pax, &sc->ax);
 119         } get_user_catch(err);
 120
 121         err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
 122
 123         return err;
 124 }
 125
 126 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 127                      struct pt_regs *regs, unsigned long mask)
 128 {
 129         int err = 0;
 130
 131         put_user_try {
 132
 133 #ifdef CONFIG_X86_32
 134                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 135                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 136                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 137                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 138 #endif /* CONFIG_X86_32 */
 139
 140                 put_user_ex(regs->di, &sc->di);
 141                 put_user_ex(regs->si, &sc->si);
 142                 put_user_ex(regs->bp, &sc->bp);
 143                 put_user_ex(regs->sp, &sc->sp);
 144                 put_user_ex(regs->bx, &sc->bx);
 145                 put_user_ex(regs->dx, &sc->dx);
 146                 put_user_ex(regs->cx, &sc->cx);
 147                 put_user_ex(regs->ax, &sc->ax);
 148 #ifdef CONFIG_X86_64
 149                 put_user_ex(regs->r8, &sc->r8);
 150                 put_user_ex(regs->r9, &sc->r9);
 151                 put_user_ex(regs->r10, &sc->r10);
 152                 put_user_ex(regs->r11, &sc->r11);
 153                 put_user_ex(regs->r12, &sc->r12);
 154                 put_user_ex(regs->r13, &sc->r13);
 155                 put_user_ex(regs->r14, &sc->r14);
 156                 put_user_ex(regs->r15, &sc->r15);
 157 #endif /* CONFIG_X86_64 */
 158
 159                 put_user_ex(current->thread.trap_nr, &sc->trapno);
 160                 put_user_ex(current->thread.error_code, &sc->err);
 161                 put_user_ex(regs->ip, &sc->ip);
 162 #ifdef CONFIG_X86_32
 163                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 164                 put_user_ex(regs->flags, &sc->flags);
 165                 put_user_ex(regs->sp, &sc->sp_at_signal);
 166                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 167 #else /* !CONFIG_X86_32 */
 168                 put_user_ex(regs->flags, &sc->flags);
 169                 put_user_ex(regs->cs, &sc->cs);
 170                 put_user_ex(0, &sc->gs);
 171                 put_user_ex(0, &sc->fs);
 172 #endif /* CONFIG_X86_32 */
 173
 174                 put_user_ex(fpstate, &sc->fpstate);
 175
 176                 /* non-iBCS2 extensions.. */
 177                 put_user_ex(mask, &sc->oldmask);
 178                 put_user_ex(current->thread.cr2, &sc->cr2);
 179         } put_user_catch(err);
 180
 181         return err;
 182 }
 183
 184 /*
 185  * Set up a signal frame.
 186  */
 187
 188 /*
 189  * Determine which stack to use..
 190  */
 191 static unsigned long align_sigframe(unsigned long sp)
 192 {
 193 #ifdef CONFIG_X86_32
 194         /*
 195          * Align the stack pointer according to the i386 ABI,
 196          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 197          */
 198         sp = ((sp + 4) & -16ul) - 4;
 199 #else /* !CONFIG_X86_32 */
 200         sp = round_down(sp, 16) - 8;
 201 #endif
 202         return sp;
 203 }
 204
 205 static inline void __user *
 206 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 207              void __user **fpstate)
 208 {
 209         /* Default to using normal stack */
 210         unsigned long math_size = 0;
 211         unsigned long sp = regs->sp;
 212         unsigned long buf_fx = 0;
 213         int onsigstack = on_sig_stack(sp);
 214
 215         /* redzone */
 216         if (config_enabled(CONFIG_X86_64))
 217                 sp -= 128;
 218
 219         if (!onsigstack) {
 220                 /* This is the X/Open sanctioned signal stack switching.  */
 221                 if (ka->sa.sa_flags & SA_ONSTACK) {
 222                         if (current->sas_ss_size)
 223                                 sp = current->sas_ss_sp + current->sas_ss_size;
 224                 } else if (config_enabled(CONFIG_X86_32) &&
 225                            (regs->ss & 0xffff) != __USER_DS &&
 226                            !(ka->sa.sa_flags & SA_RESTORER) &&
 227                            ka->sa.sa_restorer) {
 228                                 /* This is the legacy signal stack switching. */
 229                                 sp = (unsigned long) ka->sa.sa_restorer;
 230                 }
 231         }
 232
 233         if (used_math()) {
 234                 sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
 235                                      &buf_fx, &math_size);
 236                 *fpstate = (void __user *)sp;
 237         }
 238
 239         sp = align_sigframe(sp - frame_size);
 240
 241         /*
 242          * If we are on the alternate signal stack and would overflow it, don't.
 243          * Return an always-bogus address instead so we will die with SIGSEGV.
 244          */
 245         if (onsigstack && !likely(on_sig_stack(sp)))
 246                 return (void __user *)-1L;
 247
 248         /* save i387 and extended state */
 249         if (used_math() &&
 250             save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
 251                 return (void __user *)-1L;
 252
 253         return (void __user *)sp;
 254 }
 255
 256 #ifdef CONFIG_X86_32
 257 static const struct {
 258         u16 poplmovl;
 259         u32 val;
 260         u16 int80;
 261 } __attribute__((packed)) retcode = {
 262         0xb858,         /* popl %eax; movl $..., %eax */
 263         __NR_sigreturn,
 264         0x80cd,         /* int $0x80 */
 265 };
 266
 267 static const struct {
 268         u8  movl;
 269         u32 val;
 270         u16 int80;
 271         u8  pad;
 272 } __attribute__((packed)) rt_retcode = {
 273         0xb8,           /* movl $..., %eax */
 274         __NR_rt_sigreturn,
 275         0x80cd,         /* int $0x80 */
 276         0
 277 };
 278
 279 static int
 280 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 281               struct pt_regs *regs)
 282 {
 283         struct sigframe __user *frame;
 284         void __user *restorer;
 285         int err = 0;
 286         void __user *fpstate = NULL;
 287
 288         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 289
 290         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 291                 return -EFAULT;
 292
 293         if (__put_user(sig, &frame->sig))
 294                 return -EFAULT;
 295
 296         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 297                 return -EFAULT;
 298
 299         if (_NSIG_WORDS > 1) {
 300                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 301                                    sizeof(frame->extramask)))
 302                         return -EFAULT;
 303         }
 304
 305         if (current->mm->context.vdso)
 306                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 307         else
 308                 restorer = &frame->retcode;
 309         if (ka->sa.sa_flags & SA_RESTORER)
 310                 restorer = ka->sa.sa_restorer;
 311
 312         /* Set up to return from userspace.  */
 313         err |= __put_user(restorer, &frame->pretcode);
 314
 315         /*
 316          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 317          *
 318          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 319          * reasons and because gdb uses it as a signature to notice
 320          * signal handler stack frames.
 321          */
 322         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 323
 324         if (err)
 325                 return -EFAULT;
 326
 327         /* Set up registers for signal handler */
 328         regs->sp = (unsigned long)frame;
 329         regs->ip = (unsigned long)ka->sa.sa_handler;
 330         regs->ax = (unsigned long)sig;
 331         regs->dx = 0;
 332         regs->cx = 0;
 333
 334         regs->ds = __USER_DS;
 335         regs->es = __USER_DS;
 336         regs->ss = __USER_DS;
 337         regs->cs = __USER_CS;
 338
 339         return 0;
 340 }
 341
 342 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 343                             sigset_t *set, struct pt_regs *regs)
 344 {
 345         struct rt_sigframe __user *frame;
 346         void __user *restorer;
 347         int err = 0;
 348         void __user *fpstate = NULL;
 349
 350         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 351
 352         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 353                 return -EFAULT;
 354
 355         put_user_try {
 356                 put_user_ex(sig, &frame->sig);
 357                 put_user_ex(&frame->info, &frame->pinfo);
 358                 put_user_ex(&frame->uc, &frame->puc);
 359
 360                 /* Create the ucontext.  */
 361                 if (cpu_has_xsave)
 362                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 363                 else
 364                         put_user_ex(0, &frame->uc.uc_flags);
 365                 put_user_ex(0, &frame->uc.uc_link);
 366                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 367                 put_user_ex(sas_ss_flags(regs->sp),
 368                             &frame->uc.uc_stack.ss_flags);
 369                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 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         err |= copy_siginfo_to_user(&frame->info, info);
 388         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 389                                 regs, set->sig[0]);
 390         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 391
 392         if (err)
 393                 return -EFAULT;
 394
 395         /* Set up registers for signal handler */
 396         regs->sp = (unsigned long)frame;
 397         regs->ip = (unsigned long)ka->sa.sa_handler;
 398         regs->ax = (unsigned long)sig;
 399         regs->dx = (unsigned long)&frame->info;
 400         regs->cx = (unsigned long)&frame->uc;
 401
 402         regs->ds = __USER_DS;
 403         regs->es = __USER_DS;
 404         regs->ss = __USER_DS;
 405         regs->cs = __USER_CS;
 406
 407         return 0;
 408 }
 409 #else /* !CONFIG_X86_32 */
 410 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 411                             sigset_t *set, struct pt_regs *regs)
 412 {
 413         struct rt_sigframe __user *frame;
 414         void __user *fp = NULL;
 415         int err = 0;
 416         struct task_struct *me = current;
 417
 418         frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
 419
 420         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 421                 return -EFAULT;
 422
 423         if (ka->sa.sa_flags & SA_SIGINFO) {
 424                 if (copy_siginfo_to_user(&frame->info, info))
 425                         return -EFAULT;
 426         }
 427
 428         put_user_try {
 429                 /* Create the ucontext.  */
 430                 if (cpu_has_xsave)
 431                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 432                 else
 433                         put_user_ex(0, &frame->uc.uc_flags);
 434                 put_user_ex(0, &frame->uc.uc_link);
 435                 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 436                 put_user_ex(sas_ss_flags(regs->sp),
 437                             &frame->uc.uc_stack.ss_flags);
 438                 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 439
 440                 /* Set up to return from userspace.  If provided, use a stub
 441                    already in userspace.  */
 442                 /* x86-64 should always use SA_RESTORER. */
 443                 if (ka->sa.sa_flags & SA_RESTORER) {
 444                         put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 445                 } else {
 446                         /* could use a vstub here */
 447                         err |= -EFAULT;
 448                 }
 449         } put_user_catch(err);
 450
 451         err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 452         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 453
 454         if (err)
 455                 return -EFAULT;
 456
 457         /* Set up registers for signal handler */
 458         regs->di = sig;
 459         /* In case the signal handler was declared without prototypes */
 460         regs->ax = 0;
 461
 462         /* This also works for non SA_SIGINFO handlers because they expect the
 463            next argument after the signal number on the stack. */
 464         regs->si = (unsigned long)&frame->info;
 465         regs->dx = (unsigned long)&frame->uc;
 466         regs->ip = (unsigned long) ka->sa.sa_handler;
 467
 468         regs->sp = (unsigned long)frame;
 469
 470         /* Set up the CS register to run signal handlers in 64-bit mode,
 471            even if the handler happens to be interrupting 32-bit code. */
 472         regs->cs = __USER_CS;
 473
 474         return 0;
 475 }
 476 #endif /* CONFIG_X86_32 */
 477
 478 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 479                               siginfo_t *info, compat_sigset_t *set,
 480                               struct pt_regs *regs)
 481 {
 482 #ifdef CONFIG_X86_X32_ABI
 483         struct rt_sigframe_x32 __user *frame;
 484         void __user *restorer;
 485         int err = 0;
 486         void __user *fpstate = NULL;
 487
 488         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 489
 490         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 491                 return -EFAULT;
 492
 493         if (ka->sa.sa_flags & SA_SIGINFO) {
 494                 if (copy_siginfo_to_user32(&frame->info, info))
 495                         return -EFAULT;
 496         }
 497
 498         put_user_try {
 499                 /* Create the ucontext.  */
 500                 if (cpu_has_xsave)
 501                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 502                 else
 503                         put_user_ex(0, &frame->uc.uc_flags);
 504                 put_user_ex(0, &frame->uc.uc_link);
 505                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 506                 put_user_ex(sas_ss_flags(regs->sp),
 507                             &frame->uc.uc_stack.ss_flags);
 508                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 509                 put_user_ex(0, &frame->uc.uc__pad0);
 510
 511                 if (ka->sa.sa_flags & SA_RESTORER) {
 512                         restorer = ka->sa.sa_restorer;
 513                 } else {
 514                         /* could use a vstub here */
 515                         restorer = NULL;
 516                         err |= -EFAULT;
 517                 }
 518                 put_user_ex(restorer, &frame->pretcode);
 519         } put_user_catch(err);
 520
 521         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 522                                 regs, set->sig[0]);
 523         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 524
 525         if (err)
 526                 return -EFAULT;
 527
 528         /* Set up registers for signal handler */
 529         regs->sp = (unsigned long) frame;
 530         regs->ip = (unsigned long) ka->sa.sa_handler;
 531
 532         /* We use the x32 calling convention here... */
 533         regs->di = sig;
 534         regs->si = (unsigned long) &frame->info;
 535         regs->dx = (unsigned long) &frame->uc;
 536
 537         loadsegment(ds, __USER_DS);
 538         loadsegment(es, __USER_DS);
 539
 540         regs->cs = __USER_CS;
 541         regs->ss = __USER_DS;
 542 #endif  /* CONFIG_X86_X32_ABI */
 543
 544         return 0;
 545 }
 546
 547 #ifdef CONFIG_X86_32
 548 /*
 549  * Atomically swap in the new signal mask, and wait for a signal.
 550  */
 551 asmlinkage int
 552 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 553 {
 554         sigset_t blocked;
 555         siginitset(&blocked, mask);
 556         return sigsuspend(&blocked);
 557 }
 558
 559 asmlinkage int
 560 sys_sigaction(int sig, const struct old_sigaction __user *act,
 561               struct old_sigaction __user *oact)
 562 {
 563         struct k_sigaction new_ka, old_ka;
 564         int ret = 0;
 565
 566         if (act) {
 567                 old_sigset_t mask;
 568
 569                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 570                         return -EFAULT;
 571
 572                 get_user_try {
 573                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 574                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 575                         get_user_ex(mask, &act->sa_mask);
 576                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 577                 } get_user_catch(ret);
 578
 579                 if (ret)
 580                         return -EFAULT;
 581                 siginitset(&new_ka.sa.sa_mask, mask);
 582         }
 583
 584         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 585
 586         if (!ret && oact) {
 587                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 588                         return -EFAULT;
 589
 590                 put_user_try {
 591                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 592                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 593                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 594                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 595                 } put_user_catch(ret);
 596
 597                 if (ret)
 598                         return -EFAULT;
 599         }
 600
 601         return ret;
 602 }
 603 #endif /* CONFIG_X86_32 */
 604
 605 /*
 606  * Do a signal return; undo the signal stack.
 607  */
 608 #ifdef CONFIG_X86_32
 609 unsigned long sys_sigreturn(struct pt_regs *regs)
 610 {
 611         struct sigframe __user *frame;
 612         unsigned long ax;
 613         sigset_t set;
 614
 615         frame = (struct sigframe __user *)(regs->sp - 8);
 616
 617         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 618                 goto badframe;
 619         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 620                 && __copy_from_user(&set.sig[1], &frame->extramask,
 621                                     sizeof(frame->extramask))))
 622                 goto badframe;
 623
 624         set_current_blocked(&set);
 625
 626         if (restore_sigcontext(regs, &frame->sc, &ax))
 627                 goto badframe;
 628         return ax;
 629
 630 badframe:
 631         signal_fault(regs, frame, "sigreturn");
 632
 633         return 0;
 634 }
 635 #endif /* CONFIG_X86_32 */
 636
 637 long sys_rt_sigreturn(struct pt_regs *regs)
 638 {
 639         struct rt_sigframe __user *frame;
 640         unsigned long ax;
 641         sigset_t set;
 642
 643         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 644         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 645                 goto badframe;
 646         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 647                 goto badframe;
 648
 649         set_current_blocked(&set);
 650
 651         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 652                 goto badframe;
 653
 654         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 655                 goto badframe;
 656
 657         return ax;
 658
 659 badframe:
 660         signal_fault(regs, frame, "rt_sigreturn");
 661         return 0;
 662 }
 663
 664 /*
 665  * OK, we're invoking a handler:
 666  */
 667 static int signr_convert(int sig)
 668 {
 669 #ifdef CONFIG_X86_32
 670         struct thread_info *info = current_thread_info();
 671
 672         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 673                 return info->exec_domain->signal_invmap[sig];
 674 #endif /* CONFIG_X86_32 */
 675         return sig;
 676 }
 677
 678 static int
 679 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 680                 struct pt_regs *regs)
 681 {
 682         int usig = signr_convert(sig);
 683         sigset_t *set = sigmask_to_save();
 684         compat_sigset_t *cset = (compat_sigset_t *) set;
 685
 686         /* Set up the stack frame */
 687         if (is_ia32_frame()) {
 688                 if (ka->sa.sa_flags & SA_SIGINFO)
 689                         return ia32_setup_rt_frame(usig, ka, info, cset, regs);
 690                 else
 691                         return ia32_setup_frame(usig, ka, cset, regs);
 692         } else if (is_x32_frame()) {
 693                 return x32_setup_rt_frame(usig, ka, info, cset, regs);
 694         } else {
 695                 return __setup_rt_frame(sig, ka, info, set, regs);
 696         }
 697 }
 698
 699 static void
 700 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 701                 struct pt_regs *regs)
 702 {
 703         /* Are we from a system call? */
 704         if (syscall_get_nr(current, regs) >= 0) {
 705                 /* If so, check system call restarting.. */
 706                 switch (syscall_get_error(current, regs)) {
 707                 case -ERESTART_RESTARTBLOCK:
 708                 case -ERESTARTNOHAND:
 709                         regs->ax = -EINTR;
 710                         break;
 711
 712                 case -ERESTARTSYS:
 713                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 714                                 regs->ax = -EINTR;
 715                                 break;
 716                         }
 717                 /* fallthrough */
 718                 case -ERESTARTNOINTR:
 719                         regs->ax = regs->orig_ax;
 720                         regs->ip -= 2;
 721                         break;
 722                 }
 723         }
 724
 725         /*
 726          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 727          * flag so that register information in the sigcontext is correct.
 728          */
 729         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 730             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 731                 regs->flags &= ~X86_EFLAGS_TF;
 732
 733         if (setup_rt_frame(sig, ka, info, regs) < 0) {
 734                 force_sigsegv(sig, current);
 735                 return;
 736         }
 737
 738         /*
 739          * Clear the direction flag as per the ABI for function entry.
 740          */
 741         regs->flags &= ~X86_EFLAGS_DF;
 742
 743         /*
 744          * Clear TF when entering the signal handler, but
 745          * notify any tracer that was single-stepping it.
 746          * The tracer may want to single-step inside the
 747          * handler too.
 748          */
 749         regs->flags &= ~X86_EFLAGS_TF;
 750
 751         signal_delivered(sig, info, ka, regs,
 752                          test_thread_flag(TIF_SINGLESTEP));
 753 }
 754
 755 #ifdef CONFIG_X86_32
 756 #define NR_restart_syscall      __NR_restart_syscall
 757 #else /* !CONFIG_X86_32 */
 758 #define NR_restart_syscall      \
 759         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 760 #endif /* CONFIG_X86_32 */
 761
 762 /*
 763  * Note that 'init' is a special process: it doesn't get signals it doesn't
 764  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 765  * mistake.
 766  */
 767 static void do_signal(struct pt_regs *regs)
 768 {
 769         struct k_sigaction ka;
 770         siginfo_t info;
 771         int signr;
 772
 773         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 774         if (signr > 0) {
 775                 /* Whee! Actually deliver the signal.  */
 776                 handle_signal(signr, &info, &ka, regs);
 777                 return;
 778         }
 779
 780         /* Did we come from a system call? */
 781         if (syscall_get_nr(current, regs) >= 0) {
 782                 /* Restart the system call - no handlers present */
 783                 switch (syscall_get_error(current, regs)) {
 784                 case -ERESTARTNOHAND:
 785                 case -ERESTARTSYS:
 786                 case -ERESTARTNOINTR:
 787                         regs->ax = regs->orig_ax;
 788                         regs->ip -= 2;
 789                         break;
 790
 791                 case -ERESTART_RESTARTBLOCK:
 792                         regs->ax = NR_restart_syscall;
 793                         regs->ip -= 2;
 794                         break;
 795                 }
 796         }
 797
 798         /*
 799          * If there's no signal to deliver, we just put the saved sigmask
 800          * back.
 801          */
 802         restore_saved_sigmask();
 803 }
 804
 805 /*
 806  * notification of userspace execution resumption
 807  * - triggered by the TIF_WORK_MASK flags
 808  */
 809 void
 810 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 811 {
 812         rcu_user_exit();
 813
 814 #ifdef CONFIG_X86_MCE
 815         /* notify userspace of pending MCEs */
 816         if (thread_info_flags & _TIF_MCE_NOTIFY)
 817                 mce_notify_process();
 818 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 819
 820         if (thread_info_flags & _TIF_UPROBE)
 821                 uprobe_notify_resume(regs);
 822
 823         /* deal with pending signal delivery */
 824         if (thread_info_flags & _TIF_SIGPENDING)
 825                 do_signal(regs);
 826
 827         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 828                 clear_thread_flag(TIF_NOTIFY_RESUME);
 829                 tracehook_notify_resume(regs);
 830         }
 831         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 832                 fire_user_return_notifiers();
 833
 834         rcu_user_enter();
 835 }
 836
 837 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 838 {
 839         struct task_struct *me = current;
 840
 841         if (show_unhandled_signals && printk_ratelimit()) {
 842                 printk("%s"
 843                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 844                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 845                        me->comm, me->pid, where, frame,
 846                        regs->ip, regs->sp, regs->orig_ax);
 847                 print_vma_addr(" in ", regs->ip);
 848                 pr_cont("\n");
 849         }
 850
 851         force_sig(SIGSEGV, me);
 852 }
 853
 854 #ifdef CONFIG_X86_X32_ABI
 855 asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)
 856 {
 857         struct rt_sigframe_x32 __user *frame;
 858         sigset_t set;
 859         unsigned long ax;
 860
 861         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 862
 863         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 864                 goto badframe;
 865         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 866                 goto badframe;
 867
 868         set_current_blocked(&set);
 869
 870         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 871                 goto badframe;
 872
 873         if (compat_restore_altstack(&frame->uc.uc_stack))
 874                 goto badframe;
 875
 876         return ax;
 877
 878 badframe:
 879         signal_fault(regs, frame, "x32 rt_sigreturn");
 880         return 0;
 881 }
 882 #endif