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_i387_xstate(buf);
 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 sp = regs->sp;
 211         int onsigstack = on_sig_stack(sp);
 212
 213 #ifdef CONFIG_X86_64
 214         /* redzone */
 215         sp -= 128;
 216 #endif /* CONFIG_X86_64 */
 217
 218         if (!onsigstack) {
 219                 /* This is the X/Open sanctioned signal stack switching.  */
 220                 if (ka->sa.sa_flags & SA_ONSTACK) {
 221                         if (current->sas_ss_size)
 222                                 sp = current->sas_ss_sp + current->sas_ss_size;
 223                 } else {
 224 #ifdef CONFIG_X86_32
 225                         /* This is the legacy signal stack switching. */
 226                         if ((regs->ss & 0xffff) != __USER_DS &&
 227                                 !(ka->sa.sa_flags & SA_RESTORER) &&
 228                                         ka->sa.sa_restorer)
 229                                 sp = (unsigned long) ka->sa.sa_restorer;
 230 #endif /* CONFIG_X86_32 */
 231                 }
 232         }
 233
 234         if (used_math()) {
 235                 sp -= sig_xstate_size;
 236 #ifdef CONFIG_X86_64
 237                 sp = round_down(sp, 64);
 238 #endif /* CONFIG_X86_64 */
 239                 *fpstate = (void __user *)sp;
 240         }
 241
 242         sp = align_sigframe(sp - frame_size);
 243
 244         /*
 245          * If we are on the alternate signal stack and would overflow it, don't.
 246          * Return an always-bogus address instead so we will die with SIGSEGV.
 247          */
 248         if (onsigstack && !likely(on_sig_stack(sp)))
 249                 return (void __user *)-1L;
 250
 251         /* save i387 state */
 252         if (used_math() && save_i387_xstate(*fpstate) < 0)
 253                 return (void __user *)-1L;
 254
 255         return (void __user *)sp;
 256 }
 257
 258 #ifdef CONFIG_X86_32
 259 static const struct {
 260         u16 poplmovl;
 261         u32 val;
 262         u16 int80;
 263 } __attribute__((packed)) retcode = {
 264         0xb858,         /* popl %eax; movl $..., %eax */
 265         __NR_sigreturn,
 266         0x80cd,         /* int $0x80 */
 267 };
 268
 269 static const struct {
 270         u8  movl;
 271         u32 val;
 272         u16 int80;
 273         u8  pad;
 274 } __attribute__((packed)) rt_retcode = {
 275         0xb8,           /* movl $..., %eax */
 276         __NR_rt_sigreturn,
 277         0x80cd,         /* int $0x80 */
 278         0
 279 };
 280
 281 static int
 282 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 283               struct pt_regs *regs)
 284 {
 285         struct sigframe __user *frame;
 286         void __user *restorer;
 287         int err = 0;
 288         void __user *fpstate = NULL;
 289
 290         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 291
 292         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 293                 return -EFAULT;
 294
 295         if (__put_user(sig, &frame->sig))
 296                 return -EFAULT;
 297
 298         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 299                 return -EFAULT;
 300
 301         if (_NSIG_WORDS > 1) {
 302                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 303                                    sizeof(frame->extramask)))
 304                         return -EFAULT;
 305         }
 306
 307         if (current->mm->context.vdso)
 308                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
 309         else
 310                 restorer = &frame->retcode;
 311         if (ka->sa.sa_flags & SA_RESTORER)
 312                 restorer = ka->sa.sa_restorer;
 313
 314         /* Set up to return from userspace.  */
 315         err |= __put_user(restorer, &frame->pretcode);
 316
 317         /*
 318          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 319          *
 320          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 321          * reasons and because gdb uses it as a signature to notice
 322          * signal handler stack frames.
 323          */
 324         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 325
 326         if (err)
 327                 return -EFAULT;
 328
 329         /* Set up registers for signal handler */
 330         regs->sp = (unsigned long)frame;
 331         regs->ip = (unsigned long)ka->sa.sa_handler;
 332         regs->ax = (unsigned long)sig;
 333         regs->dx = 0;
 334         regs->cx = 0;
 335
 336         regs->ds = __USER_DS;
 337         regs->es = __USER_DS;
 338         regs->ss = __USER_DS;
 339         regs->cs = __USER_CS;
 340
 341         return 0;
 342 }
 343
 344 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 345                             sigset_t *set, struct pt_regs *regs)
 346 {
 347         struct rt_sigframe __user *frame;
 348         void __user *restorer;
 349         int err = 0;
 350         void __user *fpstate = NULL;
 351
 352         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 353
 354         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 355                 return -EFAULT;
 356
 357         put_user_try {
 358                 put_user_ex(sig, &frame->sig);
 359                 put_user_ex(&frame->info, &frame->pinfo);
 360                 put_user_ex(&frame->uc, &frame->puc);
 361
 362                 /* Create the ucontext.  */
 363                 if (cpu_has_xsave)
 364                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 365                 else
 366                         put_user_ex(0, &frame->uc.uc_flags);
 367                 put_user_ex(0, &frame->uc.uc_link);
 368                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 369                 put_user_ex(sas_ss_flags(regs->sp),
 370                             &frame->uc.uc_stack.ss_flags);
 371                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 372
 373                 /* Set up to return from userspace.  */
 374                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 375                 if (ka->sa.sa_flags & SA_RESTORER)
 376                         restorer = ka->sa.sa_restorer;
 377                 put_user_ex(restorer, &frame->pretcode);
 378
 379                 /*
 380                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 381                  *
 382                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 383                  * reasons and because gdb uses it as a signature to notice
 384                  * signal handler stack frames.
 385                  */
 386                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 387         } put_user_catch(err);
 388
 389         err |= copy_siginfo_to_user(&frame->info, info);
 390         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 391                                 regs, set->sig[0]);
 392         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 393
 394         if (err)
 395                 return -EFAULT;
 396
 397         /* Set up registers for signal handler */
 398         regs->sp = (unsigned long)frame;
 399         regs->ip = (unsigned long)ka->sa.sa_handler;
 400         regs->ax = (unsigned long)sig;
 401         regs->dx = (unsigned long)&frame->info;
 402         regs->cx = (unsigned long)&frame->uc;
 403
 404         regs->ds = __USER_DS;
 405         regs->es = __USER_DS;
 406         regs->ss = __USER_DS;
 407         regs->cs = __USER_CS;
 408
 409         return 0;
 410 }
 411 #else /* !CONFIG_X86_32 */
 412 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 413                             sigset_t *set, struct pt_regs *regs)
 414 {
 415         struct rt_sigframe __user *frame;
 416         void __user *fp = NULL;
 417         int err = 0;
 418         struct task_struct *me = current;
 419
 420         frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
 421
 422         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 423                 return -EFAULT;
 424
 425         if (ka->sa.sa_flags & SA_SIGINFO) {
 426                 if (copy_siginfo_to_user(&frame->info, info))
 427                         return -EFAULT;
 428         }
 429
 430         put_user_try {
 431                 /* Create the ucontext.  */
 432                 if (cpu_has_xsave)
 433                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 434                 else
 435                         put_user_ex(0, &frame->uc.uc_flags);
 436                 put_user_ex(0, &frame->uc.uc_link);
 437                 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 438                 put_user_ex(sas_ss_flags(regs->sp),
 439                             &frame->uc.uc_stack.ss_flags);
 440                 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
 441
 442                 /* Set up to return from userspace.  If provided, use a stub
 443                    already in userspace.  */
 444                 /* x86-64 should always use SA_RESTORER. */
 445                 if (ka->sa.sa_flags & SA_RESTORER) {
 446                         put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
 447                 } else {
 448                         /* could use a vstub here */
 449                         err |= -EFAULT;
 450                 }
 451         } put_user_catch(err);
 452
 453         err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 454         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 455
 456         if (err)
 457                 return -EFAULT;
 458
 459         /* Set up registers for signal handler */
 460         regs->di = sig;
 461         /* In case the signal handler was declared without prototypes */
 462         regs->ax = 0;
 463
 464         /* This also works for non SA_SIGINFO handlers because they expect the
 465            next argument after the signal number on the stack. */
 466         regs->si = (unsigned long)&frame->info;
 467         regs->dx = (unsigned long)&frame->uc;
 468         regs->ip = (unsigned long) ka->sa.sa_handler;
 469
 470         regs->sp = (unsigned long)frame;
 471
 472         /* Set up the CS register to run signal handlers in 64-bit mode,
 473            even if the handler happens to be interrupting 32-bit code. */
 474         regs->cs = __USER_CS;
 475
 476         return 0;
 477 }
 478 #endif /* CONFIG_X86_32 */
 479
 480 #ifdef CONFIG_X86_32
 481 /*
 482  * Atomically swap in the new signal mask, and wait for a signal.
 483  */
 484 asmlinkage int
 485 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 486 {
 487         sigset_t blocked;
 488         siginitset(&blocked, mask);
 489         return sigsuspend(&blocked);
 490 }
 491
 492 asmlinkage int
 493 sys_sigaction(int sig, const struct old_sigaction __user *act,
 494               struct old_sigaction __user *oact)
 495 {
 496         struct k_sigaction new_ka, old_ka;
 497         int ret = 0;
 498
 499         if (act) {
 500                 old_sigset_t mask;
 501
 502                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 503                         return -EFAULT;
 504
 505                 get_user_try {
 506                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 507                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 508                         get_user_ex(mask, &act->sa_mask);
 509                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 510                 } get_user_catch(ret);
 511
 512                 if (ret)
 513                         return -EFAULT;
 514                 siginitset(&new_ka.sa.sa_mask, mask);
 515         }
 516
 517         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 518
 519         if (!ret && oact) {
 520                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 521                         return -EFAULT;
 522
 523                 put_user_try {
 524                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 525                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 526                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 527                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 528                 } put_user_catch(ret);
 529
 530                 if (ret)
 531                         return -EFAULT;
 532         }
 533
 534         return ret;
 535 }
 536 #endif /* CONFIG_X86_32 */
 537
 538 long
 539 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 540                 struct pt_regs *regs)
 541 {
 542         return do_sigaltstack(uss, uoss, regs->sp);
 543 }
 544
 545 /*
 546  * Do a signal return; undo the signal stack.
 547  */
 548 #ifdef CONFIG_X86_32
 549 unsigned long sys_sigreturn(struct pt_regs *regs)
 550 {
 551         struct sigframe __user *frame;
 552         unsigned long ax;
 553         sigset_t set;
 554
 555         frame = (struct sigframe __user *)(regs->sp - 8);
 556
 557         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 558                 goto badframe;
 559         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 560                 && __copy_from_user(&set.sig[1], &frame->extramask,
 561                                     sizeof(frame->extramask))))
 562                 goto badframe;
 563
 564         set_current_blocked(&set);
 565
 566         if (restore_sigcontext(regs, &frame->sc, &ax))
 567                 goto badframe;
 568         return ax;
 569
 570 badframe:
 571         signal_fault(regs, frame, "sigreturn");
 572
 573         return 0;
 574 }
 575 #endif /* CONFIG_X86_32 */
 576
 577 long sys_rt_sigreturn(struct pt_regs *regs)
 578 {
 579         struct rt_sigframe __user *frame;
 580         unsigned long ax;
 581         sigset_t set;
 582
 583         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 584         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 585                 goto badframe;
 586         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 587                 goto badframe;
 588
 589         set_current_blocked(&set);
 590
 591         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 592                 goto badframe;
 593
 594         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 595                 goto badframe;
 596
 597         return ax;
 598
 599 badframe:
 600         signal_fault(regs, frame, "rt_sigreturn");
 601         return 0;
 602 }
 603
 604 /*
 605  * OK, we're invoking a handler:
 606  */
 607 static int signr_convert(int sig)
 608 {
 609 #ifdef CONFIG_X86_32
 610         struct thread_info *info = current_thread_info();
 611
 612         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 613                 return info->exec_domain->signal_invmap[sig];
 614 #endif /* CONFIG_X86_32 */
 615         return sig;
 616 }
 617
 618 #ifdef CONFIG_X86_32
 619
 620 #define is_ia32 1
 621 #define ia32_setup_frame        __setup_frame
 622 #define ia32_setup_rt_frame     __setup_rt_frame
 623
 624 #else /* !CONFIG_X86_32 */
 625
 626 #ifdef CONFIG_IA32_EMULATION
 627 #define is_ia32 test_thread_flag(TIF_IA32)
 628 #else /* !CONFIG_IA32_EMULATION */
 629 #define is_ia32 0
 630 #endif /* CONFIG_IA32_EMULATION */
 631
 632 #ifdef CONFIG_X86_X32_ABI
 633 #define is_x32  test_thread_flag(TIF_X32)
 634
 635 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 636                               siginfo_t *info, compat_sigset_t *set,
 637                               struct pt_regs *regs);
 638 #else /* !CONFIG_X86_X32_ABI */
 639 #define is_x32  0
 640 #endif /* CONFIG_X86_X32_ABI */
 641
 642 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 643                 sigset_t *set, struct pt_regs *regs);
 644 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 645                 sigset_t *set, struct pt_regs *regs);
 646
 647 #endif /* CONFIG_X86_32 */
 648
 649 static int
 650 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 651                 struct pt_regs *regs)
 652 {
 653         int usig = signr_convert(sig);
 654         sigset_t *set = sigmask_to_save();
 655
 656         /* Set up the stack frame */
 657         if (is_ia32) {
 658                 if (ka->sa.sa_flags & SA_SIGINFO)
 659                         return ia32_setup_rt_frame(usig, ka, info, set, regs);
 660                 else
 661                         return ia32_setup_frame(usig, ka, set, regs);
 662 #ifdef CONFIG_X86_X32_ABI
 663         } else if (is_x32) {
 664                 return x32_setup_rt_frame(usig, ka, info,
 665                                          (compat_sigset_t *)set, regs);
 666 #endif
 667         } else {
 668                 return __setup_rt_frame(sig, ka, info, set, regs);
 669         }
 670 }
 671
 672 static void
 673 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 674                 struct pt_regs *regs)
 675 {
 676         /* Are we from a system call? */
 677         if (syscall_get_nr(current, regs) >= 0) {
 678                 /* If so, check system call restarting.. */
 679                 switch (syscall_get_error(current, regs)) {
 680                 case -ERESTART_RESTARTBLOCK:
 681                 case -ERESTARTNOHAND:
 682                         regs->ax = -EINTR;
 683                         break;
 684
 685                 case -ERESTARTSYS:
 686                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 687                                 regs->ax = -EINTR;
 688                                 break;
 689                         }
 690                 /* fallthrough */
 691                 case -ERESTARTNOINTR:
 692                         regs->ax = regs->orig_ax;
 693                         regs->ip -= 2;
 694                         break;
 695                 }
 696         }
 697
 698         /*
 699          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 700          * flag so that register information in the sigcontext is correct.
 701          */
 702         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 703             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 704                 regs->flags &= ~X86_EFLAGS_TF;
 705
 706         if (setup_rt_frame(sig, ka, info, regs) < 0) {
 707                 force_sigsegv(sig, current);
 708                 return;
 709         }
 710
 711         /*
 712          * Clear the direction flag as per the ABI for function entry.
 713          */
 714         regs->flags &= ~X86_EFLAGS_DF;
 715
 716         /*
 717          * Clear TF when entering the signal handler, but
 718          * notify any tracer that was single-stepping it.
 719          * The tracer may want to single-step inside the
 720          * handler too.
 721          */
 722         regs->flags &= ~X86_EFLAGS_TF;
 723
 724         signal_delivered(sig, info, ka, regs,
 725                          test_thread_flag(TIF_SINGLESTEP));
 726 }
 727
 728 #ifdef CONFIG_X86_32
 729 #define NR_restart_syscall      __NR_restart_syscall
 730 #else /* !CONFIG_X86_32 */
 731 #define NR_restart_syscall      \
 732         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 733 #endif /* CONFIG_X86_32 */
 734
 735 /*
 736  * Note that 'init' is a special process: it doesn't get signals it doesn't
 737  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 738  * mistake.
 739  */
 740 static void do_signal(struct pt_regs *regs)
 741 {
 742         struct k_sigaction ka;
 743         siginfo_t info;
 744         int signr;
 745
 746         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 747         if (signr > 0) {
 748                 /* Whee! Actually deliver the signal.  */
 749                 handle_signal(signr, &info, &ka, regs);
 750                 return;
 751         }
 752
 753         /* Did we come from a system call? */
 754         if (syscall_get_nr(current, regs) >= 0) {
 755                 /* Restart the system call - no handlers present */
 756                 switch (syscall_get_error(current, regs)) {
 757                 case -ERESTARTNOHAND:
 758                 case -ERESTARTSYS:
 759                 case -ERESTARTNOINTR:
 760                         regs->ax = regs->orig_ax;
 761                         regs->ip -= 2;
 762                         break;
 763
 764                 case -ERESTART_RESTARTBLOCK:
 765                         regs->ax = NR_restart_syscall;
 766                         regs->ip -= 2;
 767                         break;
 768                 }
 769         }
 770
 771         /*
 772          * If there's no signal to deliver, we just put the saved sigmask
 773          * back.
 774          */
 775         restore_saved_sigmask();
 776 }
 777
 778 /*
 779  * notification of userspace execution resumption
 780  * - triggered by the TIF_WORK_MASK flags
 781  */
 782 void
 783 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 784 {
 785 #ifdef CONFIG_X86_MCE
 786         /* notify userspace of pending MCEs */
 787         if (thread_info_flags & _TIF_MCE_NOTIFY)
 788                 mce_notify_process();
 789 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 790
 791         if (thread_info_flags & _TIF_UPROBE) {
 792                 clear_thread_flag(TIF_UPROBE);
 793                 uprobe_notify_resume(regs);
 794         }
 795
 796         /* deal with pending signal delivery */
 797         if (thread_info_flags & _TIF_SIGPENDING)
 798                 do_signal(regs);
 799
 800         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 801                 clear_thread_flag(TIF_NOTIFY_RESUME);
 802                 tracehook_notify_resume(regs);
 803         }
 804         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 805                 fire_user_return_notifiers();
 806
 807 #ifdef CONFIG_X86_32
 808         clear_thread_flag(TIF_IRET);
 809 #endif /* CONFIG_X86_32 */
 810 }
 811
 812 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 813 {
 814         struct task_struct *me = current;
 815
 816         if (show_unhandled_signals && printk_ratelimit()) {
 817                 printk("%s"
 818                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 819                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 820                        me->comm, me->pid, where, frame,
 821                        regs->ip, regs->sp, regs->orig_ax);
 822                 print_vma_addr(" in ", regs->ip);
 823                 pr_cont("\n");
 824         }
 825
 826         force_sig(SIGSEGV, me);
 827 }
 828
 829 #ifdef CONFIG_X86_X32_ABI
 830 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 831                               siginfo_t *info, compat_sigset_t *set,
 832                               struct pt_regs *regs)
 833 {
 834         struct rt_sigframe_x32 __user *frame;
 835         void __user *restorer;
 836         int err = 0;
 837         void __user *fpstate = NULL;
 838
 839         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 840
 841         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 842                 return -EFAULT;
 843
 844         if (ka->sa.sa_flags & SA_SIGINFO) {
 845                 if (copy_siginfo_to_user32(&frame->info, info))
 846                         return -EFAULT;
 847         }
 848
 849         put_user_try {
 850                 /* Create the ucontext.  */
 851                 if (cpu_has_xsave)
 852                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 853                 else
 854                         put_user_ex(0, &frame->uc.uc_flags);
 855                 put_user_ex(0, &frame->uc.uc_link);
 856                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 857                 put_user_ex(sas_ss_flags(regs->sp),
 858                             &frame->uc.uc_stack.ss_flags);
 859                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 860                 put_user_ex(0, &frame->uc.uc__pad0);
 861
 862                 if (ka->sa.sa_flags & SA_RESTORER) {
 863                         restorer = ka->sa.sa_restorer;
 864                 } else {
 865                         /* could use a vstub here */
 866                         restorer = NULL;
 867                         err |= -EFAULT;
 868                 }
 869                 put_user_ex(restorer, &frame->pretcode);
 870         } put_user_catch(err);
 871
 872         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 873                                 regs, set->sig[0]);
 874         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 875
 876         if (err)
 877                 return -EFAULT;
 878
 879         /* Set up registers for signal handler */
 880         regs->sp = (unsigned long) frame;
 881         regs->ip = (unsigned long) ka->sa.sa_handler;
 882
 883         /* We use the x32 calling convention here... */
 884         regs->di = sig;
 885         regs->si = (unsigned long) &frame->info;
 886         regs->dx = (unsigned long) &frame->uc;
 887
 888         loadsegment(ds, __USER_DS);
 889         loadsegment(es, __USER_DS);
 890
 891         regs->cs = __USER_CS;
 892         regs->ss = __USER_DS;
 893
 894         return 0;
 895 }
 896
 897 asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)
 898 {
 899         struct rt_sigframe_x32 __user *frame;
 900         sigset_t set;
 901         unsigned long ax;
 902         struct pt_regs tregs;
 903
 904         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 905
 906         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 907                 goto badframe;
 908         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 909                 goto badframe;
 910
 911         set_current_blocked(&set);
 912
 913         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 914                 goto badframe;
 915
 916         tregs = *regs;
 917         if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
 918                 goto badframe;
 919
 920         return ax;
 921
 922 badframe:
 923         signal_fault(regs, frame, "x32 rt_sigreturn");
 924         return 0;
 925 }
 926 #endif