arch/x86/kernel/signal.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
   4  *
   5  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   6  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   7  *  2000-2002   x86-64 support by Andi Kleen
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/smp.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.h>
  18 #include <linux/tracehook.h>
  19 #include <linux/unistd.h>
  20 #include <linux/stddef.h>
  21 #include <linux/personality.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/user-return-notifier.h>
  24 #include <linux/uprobes.h>
  25 #include <linux/context_tracking.h>
  26
  27 #include <asm/processor.h>
  28 #include <asm/ucontext.h>
  29 #include <asm/fpu/internal.h>
  30 #include <asm/fpu/signal.h>
  31 #include <asm/vdso.h>
  32 #include <asm/mce.h>
  33 #include <asm/sighandling.h>
  34 #include <asm/vm86.h>
  35
  36 #ifdef CONFIG_X86_64
  37 #include <asm/proto.h>
  38 #include <asm/ia32_unistd.h>
  39 #endif /* CONFIG_X86_64 */
  40
  41 #include <asm/syscall.h>
  42 #include <asm/syscalls.h>
  43
  44 #include <asm/sigframe.h>
  45
  46 #define COPY(x)                 do {                    \
  47         get_user_ex(regs->x, &sc->x);                   \
  48 } while (0)
  49
  50 #define GET_SEG(seg)            ({                      \
  51         unsigned short tmp;                             \
  52         get_user_ex(tmp, &sc->seg);                     \
  53         tmp;                                            \
  54 })
  55
  56 #define COPY_SEG(seg)           do {                    \
  57         regs->seg = GET_SEG(seg);                       \
  58 } while (0)
  59
  60 #define COPY_SEG_CPL3(seg)      do {                    \
  61         regs->seg = GET_SEG(seg) | 3;                   \
  62 } while (0)
  63
  64 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  65 {
  66         unsigned long buf_val;
  67         void __user *buf;
  68         unsigned int tmpflags;
  69         unsigned int err = 0;
  70
  71         /* Always make any pending restarted system calls return -EINTR */
  72         current->restart_block.fn = do_no_restart_syscall;
  73
  74         get_user_try {
  75
  76 #ifdef CONFIG_X86_32
  77                 set_user_gs(regs, GET_SEG(gs));
  78                 COPY_SEG(fs);
  79                 COPY_SEG(es);
  80                 COPY_SEG(ds);
  81 #endif /* CONFIG_X86_32 */
  82
  83                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  84                 COPY(dx); COPY(cx); COPY(ip); COPY(ax);
  85
  86 #ifdef CONFIG_X86_64
  87                 COPY(r8);
  88                 COPY(r9);
  89                 COPY(r10);
  90                 COPY(r11);
  91                 COPY(r12);
  92                 COPY(r13);
  93                 COPY(r14);
  94                 COPY(r15);
  95 #endif /* CONFIG_X86_64 */
  96
  97 #ifdef CONFIG_X86_32
  98                 COPY_SEG_CPL3(cs);
  99                 COPY_SEG_CPL3(ss);
 100 #else /* !CONFIG_X86_32 */
 101                 /* Kernel saves and restores only the CS segment register on signals,
 102                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 103                  * App's signal handler can save/restore other segments if needed. */
 104                 COPY_SEG_CPL3(cs);
 105 #endif /* CONFIG_X86_32 */
 106
 107                 get_user_ex(tmpflags, &sc->flags);
 108                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 109                 regs->orig_ax = -1;             /* disable syscall checks */
 110
 111                 get_user_ex(buf_val, &sc->fpstate);
 112                 buf = (void __user *)buf_val;
 113         } get_user_catch(err);
 114
 115         err |= fpu__restore_sig(buf, config_enabled(CONFIG_X86_32));
 116
 117         force_iret();
 118
 119         return err;
 120 }
 121
 122 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 123                      struct pt_regs *regs, unsigned long mask)
 124 {
 125         int err = 0;
 126
 127         put_user_try {
 128
 129 #ifdef CONFIG_X86_32
 130                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 131                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 132                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 133                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 134 #endif /* CONFIG_X86_32 */
 135
 136                 put_user_ex(regs->di, &sc->di);
 137                 put_user_ex(regs->si, &sc->si);
 138                 put_user_ex(regs->bp, &sc->bp);
 139                 put_user_ex(regs->sp, &sc->sp);
 140                 put_user_ex(regs->bx, &sc->bx);
 141                 put_user_ex(regs->dx, &sc->dx);
 142                 put_user_ex(regs->cx, &sc->cx);
 143                 put_user_ex(regs->ax, &sc->ax);
 144 #ifdef CONFIG_X86_64
 145                 put_user_ex(regs->r8, &sc->r8);
 146                 put_user_ex(regs->r9, &sc->r9);
 147                 put_user_ex(regs->r10, &sc->r10);
 148                 put_user_ex(regs->r11, &sc->r11);
 149                 put_user_ex(regs->r12, &sc->r12);
 150                 put_user_ex(regs->r13, &sc->r13);
 151                 put_user_ex(regs->r14, &sc->r14);
 152                 put_user_ex(regs->r15, &sc->r15);
 153 #endif /* CONFIG_X86_64 */
 154
 155                 put_user_ex(current->thread.trap_nr, &sc->trapno);
 156                 put_user_ex(current->thread.error_code, &sc->err);
 157                 put_user_ex(regs->ip, &sc->ip);
 158 #ifdef CONFIG_X86_32
 159                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 160                 put_user_ex(regs->flags, &sc->flags);
 161                 put_user_ex(regs->sp, &sc->sp_at_signal);
 162                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 163 #else /* !CONFIG_X86_32 */
 164                 put_user_ex(regs->flags, &sc->flags);
 165                 put_user_ex(regs->cs, &sc->cs);
 166                 put_user_ex(0, &sc->gs);
 167                 put_user_ex(0, &sc->fs);
 168 #endif /* CONFIG_X86_32 */
 169
 170                 put_user_ex(fpstate, &sc->fpstate);
 171
 172                 /* non-iBCS2 extensions.. */
 173                 put_user_ex(mask, &sc->oldmask);
 174                 put_user_ex(current->thread.cr2, &sc->cr2);
 175         } put_user_catch(err);
 176
 177         return err;
 178 }
 179
 180 /*
 181  * Set up a signal frame.
 182  */
 183
 184 /*
 185  * Determine which stack to use..
 186  */
 187 static unsigned long align_sigframe(unsigned long sp)
 188 {
 189 #ifdef CONFIG_X86_32
 190         /*
 191          * Align the stack pointer according to the i386 ABI,
 192          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 193          */
 194         sp = ((sp + 4) & -16ul) - 4;
 195 #else /* !CONFIG_X86_32 */
 196         sp = round_down(sp, 16) - 8;
 197 #endif
 198         return sp;
 199 }
 200
 201 static void __user *
 202 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 203              void __user **fpstate)
 204 {
 205         /* Default to using normal stack */
 206         unsigned long math_size = 0;
 207         unsigned long sp = regs->sp;
 208         unsigned long buf_fx = 0;
 209         int onsigstack = on_sig_stack(sp);
 210         struct fpu *fpu = &current->thread.fpu;
 211
 212         /* redzone */
 213         if (config_enabled(CONFIG_X86_64))
 214                 sp -= 128;
 215
 216         if (!onsigstack) {
 217                 /* This is the X/Open sanctioned signal stack switching.  */
 218                 if (ka->sa.sa_flags & SA_ONSTACK) {
 219                         if (current->sas_ss_size)
 220                                 sp = current->sas_ss_sp + current->sas_ss_size;
 221                 } else if (config_enabled(CONFIG_X86_32) &&
 222                            (regs->ss & 0xffff) != __USER_DS &&
 223                            !(ka->sa.sa_flags & SA_RESTORER) &&
 224                            ka->sa.sa_restorer) {
 225                                 /* This is the legacy signal stack switching. */
 226                                 sp = (unsigned long) ka->sa.sa_restorer;
 227                 }
 228         }
 229
 230         if (fpu->fpstate_active) {
 231                 sp = fpu__alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
 232                                           &buf_fx, &math_size);
 233                 *fpstate = (void __user *)sp;
 234         }
 235
 236         sp = align_sigframe(sp - frame_size);
 237
 238         /*
 239          * If we are on the alternate signal stack and would overflow it, don't.
 240          * Return an always-bogus address instead so we will die with SIGSEGV.
 241          */
 242         if (onsigstack && !likely(on_sig_stack(sp)))
 243                 return (void __user *)-1L;
 244
 245         /* save i387 and extended state */
 246         if (fpu->fpstate_active &&
 247             copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
 248                 return (void __user *)-1L;
 249
 250         return (void __user *)sp;
 251 }
 252
 253 #ifdef CONFIG_X86_32
 254 static const struct {
 255         u16 poplmovl;
 256         u32 val;
 257         u16 int80;
 258 } __attribute__((packed)) retcode = {
 259         0xb858,         /* popl %eax; movl $..., %eax */
 260         __NR_sigreturn,
 261         0x80cd,         /* int $0x80 */
 262 };
 263
 264 static const struct {
 265         u8  movl;
 266         u32 val;
 267         u16 int80;
 268         u8  pad;
 269 } __attribute__((packed)) rt_retcode = {
 270         0xb8,           /* movl $..., %eax */
 271         __NR_rt_sigreturn,
 272         0x80cd,         /* int $0x80 */
 273         0
 274 };
 275
 276 static int
 277 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
 278               struct pt_regs *regs)
 279 {
 280         struct sigframe __user *frame;
 281         void __user *restorer;
 282         int err = 0;
 283         void __user *fpstate = NULL;
 284
 285         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 286
 287         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 288                 return -EFAULT;
 289
 290         if (__put_user(sig, &frame->sig))
 291                 return -EFAULT;
 292
 293         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 294                 return -EFAULT;
 295
 296         if (_NSIG_WORDS > 1) {
 297                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 298                                    sizeof(frame->extramask)))
 299                         return -EFAULT;
 300         }
 301
 302         if (current->mm->context.vdso)
 303                 restorer = current->mm->context.vdso +
 304                         vdso_image_32.sym___kernel_sigreturn;
 305         else
 306                 restorer = &frame->retcode;
 307         if (ksig->ka.sa.sa_flags & SA_RESTORER)
 308                 restorer = ksig->ka.sa.sa_restorer;
 309
 310         /* Set up to return from userspace.  */
 311         err |= __put_user(restorer, &frame->pretcode);
 312
 313         /*
 314          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 315          *
 316          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 317          * reasons and because gdb uses it as a signature to notice
 318          * signal handler stack frames.
 319          */
 320         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 321
 322         if (err)
 323                 return -EFAULT;
 324
 325         /* Set up registers for signal handler */
 326         regs->sp = (unsigned long)frame;
 327         regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
 328         regs->ax = (unsigned long)sig;
 329         regs->dx = 0;
 330         regs->cx = 0;
 331
 332         regs->ds = __USER_DS;
 333         regs->es = __USER_DS;
 334         regs->ss = __USER_DS;
 335         regs->cs = __USER_CS;
 336
 337         return 0;
 338 }
 339
 340 static int __setup_rt_frame(int sig, struct ksignal *ksig,
 341                             sigset_t *set, struct pt_regs *regs)
 342 {
 343         struct rt_sigframe __user *frame;
 344         void __user *restorer;
 345         int err = 0;
 346         void __user *fpstate = NULL;
 347
 348         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 349
 350         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 351                 return -EFAULT;
 352
 353         put_user_try {
 354                 put_user_ex(sig, &frame->sig);
 355                 put_user_ex(&frame->info, &frame->pinfo);
 356                 put_user_ex(&frame->uc, &frame->puc);
 357
 358                 /* Create the ucontext.  */
 359                 if (cpu_has_xsave)
 360                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 361                 else
 362                         put_user_ex(0, &frame->uc.uc_flags);
 363                 put_user_ex(0, &frame->uc.uc_link);
 364                 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 365
 366                 /* Set up to return from userspace.  */
 367                 restorer = current->mm->context.vdso +
 368                         vdso_image_32.sym___kernel_rt_sigreturn;
 369                 if (ksig->ka.sa.sa_flags & SA_RESTORER)
 370                         restorer = ksig->ka.sa.sa_restorer;
 371                 put_user_ex(restorer, &frame->pretcode);
 372
 373                 /*
 374                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 375                  *
 376                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 377                  * reasons and because gdb uses it as a signature to notice
 378                  * signal handler stack frames.
 379                  */
 380                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 381         } put_user_catch(err);
 382
 383         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 384         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 385                                 regs, set->sig[0]);
 386         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 387
 388         if (err)
 389                 return -EFAULT;
 390
 391         /* Set up registers for signal handler */
 392         regs->sp = (unsigned long)frame;
 393         regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
 394         regs->ax = (unsigned long)sig;
 395         regs->dx = (unsigned long)&frame->info;
 396         regs->cx = (unsigned long)&frame->uc;
 397
 398         regs->ds = __USER_DS;
 399         regs->es = __USER_DS;
 400         regs->ss = __USER_DS;
 401         regs->cs = __USER_CS;
 402
 403         return 0;
 404 }
 405 #else /* !CONFIG_X86_32 */
 406 static int __setup_rt_frame(int sig, struct ksignal *ksig,
 407                             sigset_t *set, struct pt_regs *regs)
 408 {
 409         struct rt_sigframe __user *frame;
 410         void __user *fp = NULL;
 411         int err = 0;
 412
 413         frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
 414
 415         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 416                 return -EFAULT;
 417
 418         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 419                 if (copy_siginfo_to_user(&frame->info, &ksig->info))
 420                         return -EFAULT;
 421         }
 422
 423         put_user_try {
 424                 /* Create the ucontext.  */
 425                 if (cpu_has_xsave)
 426                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 427                 else
 428                         put_user_ex(0, &frame->uc.uc_flags);
 429                 put_user_ex(0, &frame->uc.uc_link);
 430                 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 431
 432                 /* Set up to return from userspace.  If provided, use a stub
 433                    already in userspace.  */
 434                 /* x86-64 should always use SA_RESTORER. */
 435                 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 436                         put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
 437                 } else {
 438                         /* could use a vstub here */
 439                         err |= -EFAULT;
 440                 }
 441         } put_user_catch(err);
 442
 443         err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 444         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 445
 446         if (err)
 447                 return -EFAULT;
 448
 449         /* Set up registers for signal handler */
 450         regs->di = sig;
 451         /* In case the signal handler was declared without prototypes */
 452         regs->ax = 0;
 453
 454         /* This also works for non SA_SIGINFO handlers because they expect the
 455            next argument after the signal number on the stack. */
 456         regs->si = (unsigned long)&frame->info;
 457         regs->dx = (unsigned long)&frame->uc;
 458         regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
 459
 460         regs->sp = (unsigned long)frame;
 461
 462         /* Set up the CS register to run signal handlers in 64-bit mode,
 463            even if the handler happens to be interrupting 32-bit code. */
 464         regs->cs = __USER_CS;
 465
 466         return 0;
 467 }
 468 #endif /* CONFIG_X86_32 */
 469
 470 static int x32_setup_rt_frame(struct ksignal *ksig,
 471                               compat_sigset_t *set,
 472                               struct pt_regs *regs)
 473 {
 474 #ifdef CONFIG_X86_X32_ABI
 475         struct rt_sigframe_x32 __user *frame;
 476         void __user *restorer;
 477         int err = 0;
 478         void __user *fpstate = NULL;
 479
 480         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 481
 482         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 483                 return -EFAULT;
 484
 485         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 486                 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
 487                         return -EFAULT;
 488         }
 489
 490         put_user_try {
 491                 /* Create the ucontext.  */
 492                 if (cpu_has_xsave)
 493                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 494                 else
 495                         put_user_ex(0, &frame->uc.uc_flags);
 496                 put_user_ex(0, &frame->uc.uc_link);
 497                 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 498                 put_user_ex(0, &frame->uc.uc__pad0);
 499
 500                 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 501                         restorer = ksig->ka.sa.sa_restorer;
 502                 } else {
 503                         /* could use a vstub here */
 504                         restorer = NULL;
 505                         err |= -EFAULT;
 506                 }
 507                 put_user_ex(restorer, &frame->pretcode);
 508         } put_user_catch(err);
 509
 510         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 511                                 regs, set->sig[0]);
 512         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 513
 514         if (err)
 515                 return -EFAULT;
 516
 517         /* Set up registers for signal handler */
 518         regs->sp = (unsigned long) frame;
 519         regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
 520
 521         /* We use the x32 calling convention here... */
 522         regs->di = ksig->sig;
 523         regs->si = (unsigned long) &frame->info;
 524         regs->dx = (unsigned long) &frame->uc;
 525
 526         loadsegment(ds, __USER_DS);
 527         loadsegment(es, __USER_DS);
 528
 529         regs->cs = __USER_CS;
 530         regs->ss = __USER_DS;
 531 #endif  /* CONFIG_X86_X32_ABI */
 532
 533         return 0;
 534 }
 535
 536 /*
 537  * Do a signal return; undo the signal stack.
 538  */
 539 #ifdef CONFIG_X86_32
 540 asmlinkage unsigned long sys_sigreturn(void)
 541 {
 542         struct pt_regs *regs = current_pt_regs();
 543         struct sigframe __user *frame;
 544         sigset_t set;
 545
 546         frame = (struct sigframe __user *)(regs->sp - 8);
 547
 548         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 549                 goto badframe;
 550         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 551                 && __copy_from_user(&set.sig[1], &frame->extramask,
 552                                     sizeof(frame->extramask))))
 553                 goto badframe;
 554
 555         set_current_blocked(&set);
 556
 557         if (restore_sigcontext(regs, &frame->sc))
 558                 goto badframe;
 559         return regs->ax;
 560
 561 badframe:
 562         signal_fault(regs, frame, "sigreturn");
 563
 564         return 0;
 565 }
 566 #endif /* CONFIG_X86_32 */
 567
 568 asmlinkage long sys_rt_sigreturn(void)
 569 {
 570         struct pt_regs *regs = current_pt_regs();
 571         struct rt_sigframe __user *frame;
 572         sigset_t set;
 573
 574         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 575         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 576                 goto badframe;
 577         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 578                 goto badframe;
 579
 580         set_current_blocked(&set);
 581
 582         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 583                 goto badframe;
 584
 585         if (restore_altstack(&frame->uc.uc_stack))
 586                 goto badframe;
 587
 588         return regs->ax;
 589
 590 badframe:
 591         signal_fault(regs, frame, "rt_sigreturn");
 592         return 0;
 593 }
 594
 595 static inline int is_ia32_compat_frame(void)
 596 {
 597         return config_enabled(CONFIG_IA32_EMULATION) &&
 598                test_thread_flag(TIF_IA32);
 599 }
 600
 601 static inline int is_ia32_frame(void)
 602 {
 603         return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame();
 604 }
 605
 606 static inline int is_x32_frame(void)
 607 {
 608         return config_enabled(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32);
 609 }
 610
 611 static int
 612 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 613 {
 614         int usig = ksig->sig;
 615         sigset_t *set = sigmask_to_save();
 616         compat_sigset_t *cset = (compat_sigset_t *) set;
 617
 618         /* Set up the stack frame */
 619         if (is_ia32_frame()) {
 620                 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 621                         return ia32_setup_rt_frame(usig, ksig, cset, regs);
 622                 else
 623                         return ia32_setup_frame(usig, ksig, cset, regs);
 624         } else if (is_x32_frame()) {
 625                 return x32_setup_rt_frame(ksig, cset, regs);
 626         } else {
 627                 return __setup_rt_frame(ksig->sig, ksig, set, regs);
 628         }
 629 }
 630
 631 static void
 632 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 633 {
 634         bool stepping, failed;
 635         struct fpu *fpu = &current->thread.fpu;
 636
 637         if (v8086_mode(regs))
 638                 save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL);
 639
 640         /* Are we from a system call? */
 641         if (syscall_get_nr(current, regs) >= 0) {
 642                 /* If so, check system call restarting.. */
 643                 switch (syscall_get_error(current, regs)) {
 644                 case -ERESTART_RESTARTBLOCK:
 645                 case -ERESTARTNOHAND:
 646                         regs->ax = -EINTR;
 647                         break;
 648
 649                 case -ERESTARTSYS:
 650                         if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 651                                 regs->ax = -EINTR;
 652                                 break;
 653                         }
 654                 /* fallthrough */
 655                 case -ERESTARTNOINTR:
 656                         regs->ax = regs->orig_ax;
 657                         regs->ip -= 2;
 658                         break;
 659                 }
 660         }
 661
 662         /*
 663          * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
 664          * so that register information in the sigcontext is correct and
 665          * then notify the tracer before entering the signal handler.
 666          */
 667         stepping = test_thread_flag(TIF_SINGLESTEP);
 668         if (stepping)
 669                 user_disable_single_step(current);
 670
 671         failed = (setup_rt_frame(ksig, regs) < 0);
 672         if (!failed) {
 673                 /*
 674                  * Clear the direction flag as per the ABI for function entry.
 675                  *
 676                  * Clear RF when entering the signal handler, because
 677                  * it might disable possible debug exception from the
 678                  * signal handler.
 679                  *
 680                  * Clear TF for the case when it wasn't set by debugger to
 681                  * avoid the recursive send_sigtrap() in SIGTRAP handler.
 682                  */
 683                 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
 684                 /*
 685                  * Ensure the signal handler starts with the new fpu state.
 686                  */
 687                 if (fpu->fpstate_active)
 688                         fpu__clear(fpu);
 689         }
 690         signal_setup_done(failed, ksig, stepping);
 691 }
 692
 693 #ifdef CONFIG_X86_32
 694 #define NR_restart_syscall      __NR_restart_syscall
 695 #else /* !CONFIG_X86_32 */
 696 #define NR_restart_syscall      \
 697         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 698 #endif /* CONFIG_X86_32 */
 699
 700 /*
 701  * Note that 'init' is a special process: it doesn't get signals it doesn't
 702  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 703  * mistake.
 704  */
 705 void do_signal(struct pt_regs *regs)
 706 {
 707         struct ksignal ksig;
 708
 709         if (get_signal(&ksig)) {
 710                 /* Whee! Actually deliver the signal.  */
 711                 handle_signal(&ksig, regs);
 712                 return;
 713         }
 714
 715         /* Did we come from a system call? */
 716         if (syscall_get_nr(current, regs) >= 0) {
 717                 /* Restart the system call - no handlers present */
 718                 switch (syscall_get_error(current, regs)) {
 719                 case -ERESTARTNOHAND:
 720                 case -ERESTARTSYS:
 721                 case -ERESTARTNOINTR:
 722                         regs->ax = regs->orig_ax;
 723                         regs->ip -= 2;
 724                         break;
 725
 726                 case -ERESTART_RESTARTBLOCK:
 727                         regs->ax = NR_restart_syscall;
 728                         regs->ip -= 2;
 729                         break;
 730                 }
 731         }
 732
 733         /*
 734          * If there's no signal to deliver, we just put the saved sigmask
 735          * back.
 736          */
 737         restore_saved_sigmask();
 738 }
 739
 740 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 741 {
 742         struct task_struct *me = current;
 743
 744         if (show_unhandled_signals && printk_ratelimit()) {
 745                 printk("%s"
 746                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 747                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 748                        me->comm, me->pid, where, frame,
 749                        regs->ip, regs->sp, regs->orig_ax);
 750                 print_vma_addr(" in ", regs->ip);
 751                 pr_cont("\n");
 752         }
 753
 754         force_sig(SIGSEGV, me);
 755 }
 756
 757 #ifdef CONFIG_X86_X32_ABI
 758 asmlinkage long sys32_x32_rt_sigreturn(void)
 759 {
 760         struct pt_regs *regs = current_pt_regs();
 761         struct rt_sigframe_x32 __user *frame;
 762         sigset_t set;
 763
 764         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 765
 766         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 767                 goto badframe;
 768         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 769                 goto badframe;
 770
 771         set_current_blocked(&set);
 772
 773         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 774                 goto badframe;
 775
 776         if (compat_restore_altstack(&frame->uc.uc_stack))
 777                 goto badframe;
 778
 779         return regs->ax;
 780
 781 badframe:
 782         signal_fault(regs, frame, "x32 rt_sigreturn");
 783         return 0;
 784 }
 785 #endif