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                 err |= restore_i387_xstate(buf);
 118
 119                 get_user_ex(*pax, &sc->ax);
 120         } get_user_catch(err);
 121
 122         return err;
 123 }
 124
 125 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 126                      struct pt_regs *regs, unsigned long mask)
 127 {
 128         int err = 0;
 129
 130         put_user_try {
 131
 132 #ifdef CONFIG_X86_32
 133                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 134                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 135                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 136                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 137 #endif /* CONFIG_X86_32 */
 138
 139                 put_user_ex(regs->di, &sc->di);
 140                 put_user_ex(regs->si, &sc->si);
 141                 put_user_ex(regs->bp, &sc->bp);
 142                 put_user_ex(regs->sp, &sc->sp);
 143                 put_user_ex(regs->bx, &sc->bx);
 144                 put_user_ex(regs->dx, &sc->dx);
 145                 put_user_ex(regs->cx, &sc->cx);
 146                 put_user_ex(regs->ax, &sc->ax);
 147 #ifdef CONFIG_X86_64
 148                 put_user_ex(regs->r8, &sc->r8);
 149                 put_user_ex(regs->r9, &sc->r9);
 150                 put_user_ex(regs->r10, &sc->r10);
 151                 put_user_ex(regs->r11, &sc->r11);
 152                 put_user_ex(regs->r12, &sc->r12);
 153                 put_user_ex(regs->r13, &sc->r13);
 154                 put_user_ex(regs->r14, &sc->r14);
 155                 put_user_ex(regs->r15, &sc->r15);
 156 #endif /* CONFIG_X86_64 */
 157
 158                 put_user_ex(current->thread.trap_nr, &sc->trapno);
 159                 put_user_ex(current->thread.error_code, &sc->err);
 160                 put_user_ex(regs->ip, &sc->ip);
 161 #ifdef CONFIG_X86_32
 162                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 163                 put_user_ex(regs->flags, &sc->flags);
 164                 put_user_ex(regs->sp, &sc->sp_at_signal);
 165                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 166 #else /* !CONFIG_X86_32 */
 167                 put_user_ex(regs->flags, &sc->flags);
 168                 put_user_ex(regs->cs, &sc->cs);
 169                 put_user_ex(0, &sc->gs);
 170                 put_user_ex(0, &sc->fs);
 171 #endif /* CONFIG_X86_32 */
 172
 173                 put_user_ex(fpstate, &sc->fpstate);
 174
 175                 /* non-iBCS2 extensions.. */
 176                 put_user_ex(mask, &sc->oldmask);
 177                 put_user_ex(current->thread.cr2, &sc->cr2);
 178         } put_user_catch(err);
 179
 180         return err;
 181 }
 182
 183 /*
 184  * Set up a signal frame.
 185  */
 186
 187 /*
 188  * Determine which stack to use..
 189  */
 190 static unsigned long align_sigframe(unsigned long sp)
 191 {
 192 #ifdef CONFIG_X86_32
 193         /*
 194          * Align the stack pointer according to the i386 ABI,
 195          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 196          */
 197         sp = ((sp + 4) & -16ul) - 4;
 198 #else /* !CONFIG_X86_32 */
 199         sp = round_down(sp, 16) - 8;
 200 #endif
 201         return sp;
 202 }
 203
 204 static inline void __user *
 205 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 206              void __user **fpstate)
 207 {
 208         /* Default to using normal stack */
 209         unsigned long sp = regs->sp;
 210         int onsigstack = on_sig_stack(sp);
 211
 212 #ifdef CONFIG_X86_64
 213         /* redzone */
 214         sp -= 128;
 215 #endif /* CONFIG_X86_64 */
 216
 217         if (!onsigstack) {
 218                 /* This is the X/Open sanctioned signal stack switching.  */
 219                 if (ka->sa.sa_flags & SA_ONSTACK) {
 220                         if (current->sas_ss_size)
 221                                 sp = current->sas_ss_sp + current->sas_ss_size;
 222                 } else {
 223 #ifdef CONFIG_X86_32
 224                         /* This is the legacy signal stack switching. */
 225                         if ((regs->ss & 0xffff) != __USER_DS &&
 226                                 !(ka->sa.sa_flags & SA_RESTORER) &&
 227                                         ka->sa.sa_restorer)
 228                                 sp = (unsigned long) ka->sa.sa_restorer;
 229 #endif /* CONFIG_X86_32 */
 230                 }
 231         }
 232
 233         if (used_math()) {
 234                 sp -= sig_xstate_size;
 235 #ifdef CONFIG_X86_64
 236                 sp = round_down(sp, 64);
 237 #endif /* CONFIG_X86_64 */
 238                 *fpstate = (void __user *)sp;
 239         }
 240
 241         sp = align_sigframe(sp - frame_size);
 242
 243         /*
 244          * If we are on the alternate signal stack and would overflow it, don't.
 245          * Return an always-bogus address instead so we will die with SIGSEGV.
 246          */
 247         if (onsigstack && !likely(on_sig_stack(sp)))
 248                 return (void __user *)-1L;
 249
 250         /* save i387 state */
 251         if (used_math() && save_i387_xstate(*fpstate) < 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                 err |= copy_siginfo_to_user(&frame->info, info);
 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                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 373                                         regs, set->sig[0]);
 374                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 375
 376                 /* Set up to return from userspace.  */
 377                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
 378                 if (ka->sa.sa_flags & SA_RESTORER)
 379                         restorer = ka->sa.sa_restorer;
 380                 put_user_ex(restorer, &frame->pretcode);
 381
 382                 /*
 383                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 384                  *
 385                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 386                  * reasons and because gdb uses it as a signature to notice
 387                  * signal handler stack frames.
 388                  */
 389                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 390         } put_user_catch(err);
 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                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 440                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 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         if (err)
 454                 return -EFAULT;
 455
 456         /* Set up registers for signal handler */
 457         regs->di = sig;
 458         /* In case the signal handler was declared without prototypes */
 459         regs->ax = 0;
 460
 461         /* This also works for non SA_SIGINFO handlers because they expect the
 462            next argument after the signal number on the stack. */
 463         regs->si = (unsigned long)&frame->info;
 464         regs->dx = (unsigned long)&frame->uc;
 465         regs->ip = (unsigned long) ka->sa.sa_handler;
 466
 467         regs->sp = (unsigned long)frame;
 468
 469         /* Set up the CS register to run signal handlers in 64-bit mode,
 470            even if the handler happens to be interrupting 32-bit code. */
 471         regs->cs = __USER_CS;
 472
 473         return 0;
 474 }
 475 #endif /* CONFIG_X86_32 */
 476
 477 #ifdef CONFIG_X86_32
 478 /*
 479  * Atomically swap in the new signal mask, and wait for a signal.
 480  */
 481 asmlinkage int
 482 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 483 {
 484         sigset_t blocked;
 485         siginitset(&blocked, mask);
 486         return sigsuspend(&blocked);
 487 }
 488
 489 asmlinkage int
 490 sys_sigaction(int sig, const struct old_sigaction __user *act,
 491               struct old_sigaction __user *oact)
 492 {
 493         struct k_sigaction new_ka, old_ka;
 494         int ret = 0;
 495
 496         if (act) {
 497                 old_sigset_t mask;
 498
 499                 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
 500                         return -EFAULT;
 501
 502                 get_user_try {
 503                         get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
 504                         get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
 505                         get_user_ex(mask, &act->sa_mask);
 506                         get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
 507                 } get_user_catch(ret);
 508
 509                 if (ret)
 510                         return -EFAULT;
 511                 siginitset(&new_ka.sa.sa_mask, mask);
 512         }
 513
 514         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 515
 516         if (!ret && oact) {
 517                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
 518                         return -EFAULT;
 519
 520                 put_user_try {
 521                         put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
 522                         put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
 523                         put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 524                         put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
 525                 } put_user_catch(ret);
 526
 527                 if (ret)
 528                         return -EFAULT;
 529         }
 530
 531         return ret;
 532 }
 533 #endif /* CONFIG_X86_32 */
 534
 535 long
 536 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
 537                 struct pt_regs *regs)
 538 {
 539         return do_sigaltstack(uss, uoss, regs->sp);
 540 }
 541
 542 /*
 543  * Do a signal return; undo the signal stack.
 544  */
 545 #ifdef CONFIG_X86_32
 546 unsigned long sys_sigreturn(struct pt_regs *regs)
 547 {
 548         struct sigframe __user *frame;
 549         unsigned long ax;
 550         sigset_t set;
 551
 552         frame = (struct sigframe __user *)(regs->sp - 8);
 553
 554         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 555                 goto badframe;
 556         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 557                 && __copy_from_user(&set.sig[1], &frame->extramask,
 558                                     sizeof(frame->extramask))))
 559                 goto badframe;
 560
 561         set_current_blocked(&set);
 562
 563         if (restore_sigcontext(regs, &frame->sc, &ax))
 564                 goto badframe;
 565         return ax;
 566
 567 badframe:
 568         signal_fault(regs, frame, "sigreturn");
 569
 570         return 0;
 571 }
 572 #endif /* CONFIG_X86_32 */
 573
 574 long sys_rt_sigreturn(struct pt_regs *regs)
 575 {
 576         struct rt_sigframe __user *frame;
 577         unsigned long ax;
 578         sigset_t set;
 579
 580         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 581         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 582                 goto badframe;
 583         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 584                 goto badframe;
 585
 586         set_current_blocked(&set);
 587
 588         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 589                 goto badframe;
 590
 591         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 592                 goto badframe;
 593
 594         return ax;
 595
 596 badframe:
 597         signal_fault(regs, frame, "rt_sigreturn");
 598         return 0;
 599 }
 600
 601 /*
 602  * OK, we're invoking a handler:
 603  */
 604 static int signr_convert(int sig)
 605 {
 606 #ifdef CONFIG_X86_32
 607         struct thread_info *info = current_thread_info();
 608
 609         if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
 610                 return info->exec_domain->signal_invmap[sig];
 611 #endif /* CONFIG_X86_32 */
 612         return sig;
 613 }
 614
 615 #ifdef CONFIG_X86_32
 616
 617 #define is_ia32 1
 618 #define ia32_setup_frame        __setup_frame
 619 #define ia32_setup_rt_frame     __setup_rt_frame
 620
 621 #else /* !CONFIG_X86_32 */
 622
 623 #ifdef CONFIG_IA32_EMULATION
 624 #define is_ia32 test_thread_flag(TIF_IA32)
 625 #else /* !CONFIG_IA32_EMULATION */
 626 #define is_ia32 0
 627 #endif /* CONFIG_IA32_EMULATION */
 628
 629 #ifdef CONFIG_X86_X32_ABI
 630 #define is_x32  test_thread_flag(TIF_X32)
 631
 632 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 633                               siginfo_t *info, compat_sigset_t *set,
 634                               struct pt_regs *regs);
 635 #else /* !CONFIG_X86_X32_ABI */
 636 #define is_x32  0
 637 #endif /* CONFIG_X86_X32_ABI */
 638
 639 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 640                 sigset_t *set, struct pt_regs *regs);
 641 int ia32_setup_frame(int sig, struct k_sigaction *ka,
 642                 sigset_t *set, struct pt_regs *regs);
 643
 644 #endif /* CONFIG_X86_32 */
 645
 646 static int
 647 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 648                 struct pt_regs *regs)
 649 {
 650         int usig = signr_convert(sig);
 651         sigset_t *set = sigmask_to_save();
 652
 653         /* Set up the stack frame */
 654         if (is_ia32) {
 655                 if (ka->sa.sa_flags & SA_SIGINFO)
 656                         return ia32_setup_rt_frame(usig, ka, info, set, regs);
 657                 else
 658                         return ia32_setup_frame(usig, ka, set, regs);
 659 #ifdef CONFIG_X86_X32_ABI
 660         } else if (is_x32) {
 661                 return x32_setup_rt_frame(usig, ka, info,
 662                                          (compat_sigset_t *)set, regs);
 663 #endif
 664         } else {
 665                 return __setup_rt_frame(sig, ka, info, set, regs);
 666         }
 667 }
 668
 669 static void
 670 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 671                 struct pt_regs *regs)
 672 {
 673         /* Are we from a system call? */
 674         if (syscall_get_nr(current, regs) >= 0) {
 675                 /* If so, check system call restarting.. */
 676                 switch (syscall_get_error(current, regs)) {
 677                 case -ERESTART_RESTARTBLOCK:
 678                 case -ERESTARTNOHAND:
 679                         regs->ax = -EINTR;
 680                         break;
 681
 682                 case -ERESTARTSYS:
 683                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 684                                 regs->ax = -EINTR;
 685                                 break;
 686                         }
 687                 /* fallthrough */
 688                 case -ERESTARTNOINTR:
 689                         regs->ax = regs->orig_ax;
 690                         regs->ip -= 2;
 691                         break;
 692                 }
 693         }
 694
 695         /*
 696          * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
 697          * flag so that register information in the sigcontext is correct.
 698          */
 699         if (unlikely(regs->flags & X86_EFLAGS_TF) &&
 700             likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
 701                 regs->flags &= ~X86_EFLAGS_TF;
 702
 703         if (setup_rt_frame(sig, ka, info, regs) < 0) {
 704                 force_sigsegv(sig, current);
 705                 return;
 706         }
 707
 708         /*
 709          * Clear the direction flag as per the ABI for function entry.
 710          */
 711         regs->flags &= ~X86_EFLAGS_DF;
 712
 713         /*
 714          * Clear TF when entering the signal handler, but
 715          * notify any tracer that was single-stepping it.
 716          * The tracer may want to single-step inside the
 717          * handler too.
 718          */
 719         regs->flags &= ~X86_EFLAGS_TF;
 720
 721         signal_delivered(sig, info, ka, regs,
 722                          test_thread_flag(TIF_SINGLESTEP));
 723 }
 724
 725 #ifdef CONFIG_X86_32
 726 #define NR_restart_syscall      __NR_restart_syscall
 727 #else /* !CONFIG_X86_32 */
 728 #define NR_restart_syscall      \
 729         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 730 #endif /* CONFIG_X86_32 */
 731
 732 /*
 733  * Note that 'init' is a special process: it doesn't get signals it doesn't
 734  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 735  * mistake.
 736  */
 737 static void do_signal(struct pt_regs *regs)
 738 {
 739         struct k_sigaction ka;
 740         siginfo_t info;
 741         int signr;
 742
 743         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 744         if (signr > 0) {
 745                 /* Whee! Actually deliver the signal.  */
 746                 handle_signal(signr, &info, &ka, regs);
 747                 return;
 748         }
 749
 750         /* Did we come from a system call? */
 751         if (syscall_get_nr(current, regs) >= 0) {
 752                 /* Restart the system call - no handlers present */
 753                 switch (syscall_get_error(current, regs)) {
 754                 case -ERESTARTNOHAND:
 755                 case -ERESTARTSYS:
 756                 case -ERESTARTNOINTR:
 757                         regs->ax = regs->orig_ax;
 758                         regs->ip -= 2;
 759                         break;
 760
 761                 case -ERESTART_RESTARTBLOCK:
 762                         regs->ax = NR_restart_syscall;
 763                         regs->ip -= 2;
 764                         break;
 765                 }
 766         }
 767
 768         /*
 769          * If there's no signal to deliver, we just put the saved sigmask
 770          * back.
 771          */
 772         restore_saved_sigmask();
 773 }
 774
 775 /*
 776  * notification of userspace execution resumption
 777  * - triggered by the TIF_WORK_MASK flags
 778  */
 779 void
 780 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 781 {
 782 #ifdef CONFIG_X86_MCE
 783         /* notify userspace of pending MCEs */
 784         if (thread_info_flags & _TIF_MCE_NOTIFY)
 785                 mce_notify_process();
 786 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 787
 788         if (thread_info_flags & _TIF_UPROBE) {
 789                 clear_thread_flag(TIF_UPROBE);
 790                 uprobe_notify_resume(regs);
 791         }
 792
 793         /* deal with pending signal delivery */
 794         if (thread_info_flags & _TIF_SIGPENDING)
 795                 do_signal(regs);
 796
 797         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 798                 clear_thread_flag(TIF_NOTIFY_RESUME);
 799                 tracehook_notify_resume(regs);
 800         }
 801         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 802                 fire_user_return_notifiers();
 803
 804 #ifdef CONFIG_X86_32
 805         clear_thread_flag(TIF_IRET);
 806 #endif /* CONFIG_X86_32 */
 807 }
 808
 809 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 810 {
 811         struct task_struct *me = current;
 812
 813         if (show_unhandled_signals && printk_ratelimit()) {
 814                 printk("%s"
 815                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 816                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 817                        me->comm, me->pid, where, frame,
 818                        regs->ip, regs->sp, regs->orig_ax);
 819                 print_vma_addr(" in ", regs->ip);
 820                 pr_cont("\n");
 821         }
 822
 823         force_sig(SIGSEGV, me);
 824 }
 825
 826 #ifdef CONFIG_X86_X32_ABI
 827 static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
 828                               siginfo_t *info, compat_sigset_t *set,
 829                               struct pt_regs *regs)
 830 {
 831         struct rt_sigframe_x32 __user *frame;
 832         void __user *restorer;
 833         int err = 0;
 834         void __user *fpstate = NULL;
 835
 836         frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
 837
 838         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 839                 return -EFAULT;
 840
 841         if (ka->sa.sa_flags & SA_SIGINFO) {
 842                 if (copy_siginfo_to_user32(&frame->info, info))
 843                         return -EFAULT;
 844         }
 845
 846         put_user_try {
 847                 /* Create the ucontext.  */
 848                 if (cpu_has_xsave)
 849                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 850                 else
 851                         put_user_ex(0, &frame->uc.uc_flags);
 852                 put_user_ex(0, &frame->uc.uc_link);
 853                 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 854                 put_user_ex(sas_ss_flags(regs->sp),
 855                             &frame->uc.uc_stack.ss_flags);
 856                 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 857                 put_user_ex(0, &frame->uc.uc__pad0);
 858                 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 859                                         regs, set->sig[0]);
 860                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 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         if (err)
 873                 return -EFAULT;
 874
 875         /* Set up registers for signal handler */
 876         regs->sp = (unsigned long) frame;
 877         regs->ip = (unsigned long) ka->sa.sa_handler;
 878
 879         /* We use the x32 calling convention here... */
 880         regs->di = sig;
 881         regs->si = (unsigned long) &frame->info;
 882         regs->dx = (unsigned long) &frame->uc;
 883
 884         loadsegment(ds, __USER_DS);
 885         loadsegment(es, __USER_DS);
 886
 887         regs->cs = __USER_CS;
 888         regs->ss = __USER_DS;
 889
 890         return 0;
 891 }
 892
 893 asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)
 894 {
 895         struct rt_sigframe_x32 __user *frame;
 896         sigset_t set;
 897         unsigned long ax;
 898         struct pt_regs tregs;
 899
 900         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 901
 902         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 903                 goto badframe;
 904         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 905                 goto badframe;
 906
 907         set_current_blocked(&set);
 908
 909         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
 910                 goto badframe;
 911
 912         tregs = *regs;
 913         if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
 914                 goto badframe;
 915
 916         return ax;
 917
 918 badframe:
 919         signal_fault(regs, frame, "x32 rt_sigreturn");
 920         return 0;
 921 }
 922 #endif