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
  35 #ifdef CONFIG_X86_64
  36 #include <asm/proto.h>
  37 #include <asm/ia32_unistd.h>
  38 #include <asm/sys_ia32.h>
  39 #endif /* CONFIG_X86_64 */
  40
  41 #include <asm/syscall.h>
  42 #include <asm/syscalls.h>
  43
  44 #include <asm/sigframe.h>
  45
  46 #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         void __user *buf;
  67         unsigned int tmpflags;
  68         unsigned int err = 0;
  69
  70         /* Always make any pending restarted system calls return -EINTR */
  71         current->restart_block.fn = do_no_restart_syscall;
  72
  73         get_user_try {
  74
  75 #ifdef CONFIG_X86_32
  76                 set_user_gs(regs, GET_SEG(gs));
  77                 COPY_SEG(fs);
  78                 COPY_SEG(es);
  79                 COPY_SEG(ds);
  80 #endif /* CONFIG_X86_32 */
  81
  82                 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  83                 COPY(dx); COPY(cx); COPY(ip); COPY(ax);
  84
  85 #ifdef CONFIG_X86_64
  86                 COPY(r8);
  87                 COPY(r9);
  88                 COPY(r10);
  89                 COPY(r11);
  90                 COPY(r12);
  91                 COPY(r13);
  92                 COPY(r14);
  93                 COPY(r15);
  94 #endif /* CONFIG_X86_64 */
  95
  96 #ifdef CONFIG_X86_32
  97                 COPY_SEG_CPL3(cs);
  98                 COPY_SEG_CPL3(ss);
  99 #else /* !CONFIG_X86_32 */
 100                 /* Kernel saves and restores only the CS segment register on signals,
 101                  * which is the bare minimum needed to allow mixed 32/64-bit code.
 102                  * App's signal handler can save/restore other segments if needed. */
 103                 COPY_SEG_CPL3(cs);
 104 #endif /* CONFIG_X86_32 */
 105
 106                 get_user_ex(tmpflags, &sc->flags);
 107                 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
 108                 regs->orig_ax = -1;             /* disable syscall checks */
 109
 110                 get_user_ex(buf, &sc->fpstate);
 111         } get_user_catch(err);
 112
 113         err |= fpu__restore_sig(buf, config_enabled(CONFIG_X86_32));
 114
 115         force_iret();
 116
 117         return err;
 118 }
 119
 120 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 121                      struct pt_regs *regs, unsigned long mask)
 122 {
 123         int err = 0;
 124
 125         put_user_try {
 126
 127 #ifdef CONFIG_X86_32
 128                 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
 129                 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
 130                 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
 131                 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
 132 #endif /* CONFIG_X86_32 */
 133
 134                 put_user_ex(regs->di, &sc->di);
 135                 put_user_ex(regs->si, &sc->si);
 136                 put_user_ex(regs->bp, &sc->bp);
 137                 put_user_ex(regs->sp, &sc->sp);
 138                 put_user_ex(regs->bx, &sc->bx);
 139                 put_user_ex(regs->dx, &sc->dx);
 140                 put_user_ex(regs->cx, &sc->cx);
 141                 put_user_ex(regs->ax, &sc->ax);
 142 #ifdef CONFIG_X86_64
 143                 put_user_ex(regs->r8, &sc->r8);
 144                 put_user_ex(regs->r9, &sc->r9);
 145                 put_user_ex(regs->r10, &sc->r10);
 146                 put_user_ex(regs->r11, &sc->r11);
 147                 put_user_ex(regs->r12, &sc->r12);
 148                 put_user_ex(regs->r13, &sc->r13);
 149                 put_user_ex(regs->r14, &sc->r14);
 150                 put_user_ex(regs->r15, &sc->r15);
 151 #endif /* CONFIG_X86_64 */
 152
 153                 put_user_ex(current->thread.trap_nr, &sc->trapno);
 154                 put_user_ex(current->thread.error_code, &sc->err);
 155                 put_user_ex(regs->ip, &sc->ip);
 156 #ifdef CONFIG_X86_32
 157                 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
 158                 put_user_ex(regs->flags, &sc->flags);
 159                 put_user_ex(regs->sp, &sc->sp_at_signal);
 160                 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
 161 #else /* !CONFIG_X86_32 */
 162                 put_user_ex(regs->flags, &sc->flags);
 163                 put_user_ex(regs->cs, &sc->cs);
 164                 put_user_ex(0, &sc->gs);
 165                 put_user_ex(0, &sc->fs);
 166 #endif /* CONFIG_X86_32 */
 167
 168                 put_user_ex(fpstate, &sc->fpstate);
 169
 170                 /* non-iBCS2 extensions.. */
 171                 put_user_ex(mask, &sc->oldmask);
 172                 put_user_ex(current->thread.cr2, &sc->cr2);
 173         } put_user_catch(err);
 174
 175         return err;
 176 }
 177
 178 /*
 179  * Set up a signal frame.
 180  */
 181
 182 /*
 183  * Determine which stack to use..
 184  */
 185 static unsigned long align_sigframe(unsigned long sp)
 186 {
 187 #ifdef CONFIG_X86_32
 188         /*
 189          * Align the stack pointer according to the i386 ABI,
 190          * i.e. so that on function entry ((sp + 4) & 15) == 0.
 191          */
 192         sp = ((sp + 4) & -16ul) - 4;
 193 #else /* !CONFIG_X86_32 */
 194         sp = round_down(sp, 16) - 8;
 195 #endif
 196         return sp;
 197 }
 198
 199 static inline void __user *
 200 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 201              void __user **fpstate)
 202 {
 203         /* Default to using normal stack */
 204         unsigned long math_size = 0;
 205         unsigned long sp = regs->sp;
 206         unsigned long buf_fx = 0;
 207         int onsigstack = on_sig_stack(sp);
 208         struct fpu *fpu = &current->thread.fpu;
 209
 210         /* redzone */
 211         if (config_enabled(CONFIG_X86_64))
 212                 sp -= 128;
 213
 214         if (!onsigstack) {
 215                 /* This is the X/Open sanctioned signal stack switching.  */
 216                 if (ka->sa.sa_flags & SA_ONSTACK) {
 217                         if (current->sas_ss_size)
 218                                 sp = current->sas_ss_sp + current->sas_ss_size;
 219                 } else if (config_enabled(CONFIG_X86_32) &&
 220                            (regs->ss & 0xffff) != __USER_DS &&
 221                            !(ka->sa.sa_flags & SA_RESTORER) &&
 222                            ka->sa.sa_restorer) {
 223                                 /* This is the legacy signal stack switching. */
 224                                 sp = (unsigned long) ka->sa.sa_restorer;
 225                 }
 226         }
 227
 228         if (fpu->fpstate_active) {
 229                 sp = fpu__alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
 230                                           &buf_fx, &math_size);
 231                 *fpstate = (void __user *)sp;
 232         }
 233
 234         sp = align_sigframe(sp - frame_size);
 235
 236         /*
 237          * If we are on the alternate signal stack and would overflow it, don't.
 238          * Return an always-bogus address instead so we will die with SIGSEGV.
 239          */
 240         if (onsigstack && !likely(on_sig_stack(sp)))
 241                 return (void __user *)-1L;
 242
 243         /* save i387 and extended state */
 244         if (fpu->fpstate_active &&
 245             copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
 246                 return (void __user *)-1L;
 247
 248         return (void __user *)sp;
 249 }
 250
 251 #ifdef CONFIG_X86_32
 252 static const struct {
 253         u16 poplmovl;
 254         u32 val;
 255         u16 int80;
 256 } __attribute__((packed)) retcode = {
 257         0xb858,         /* popl %eax; movl $..., %eax */
 258         __NR_sigreturn,
 259         0x80cd,         /* int $0x80 */
 260 };
 261
 262 static const struct {
 263         u8  movl;
 264         u32 val;
 265         u16 int80;
 266         u8  pad;
 267 } __attribute__((packed)) rt_retcode = {
 268         0xb8,           /* movl $..., %eax */
 269         __NR_rt_sigreturn,
 270         0x80cd,         /* int $0x80 */
 271         0
 272 };
 273
 274 static int
 275 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
 276               struct pt_regs *regs)
 277 {
 278         struct sigframe __user *frame;
 279         void __user *restorer;
 280         int err = 0;
 281         void __user *fpstate = NULL;
 282
 283         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 284
 285         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 286                 return -EFAULT;
 287
 288         if (__put_user(sig, &frame->sig))
 289                 return -EFAULT;
 290
 291         if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
 292                 return -EFAULT;
 293
 294         if (_NSIG_WORDS > 1) {
 295                 if (__copy_to_user(&frame->extramask, &set->sig[1],
 296                                    sizeof(frame->extramask)))
 297                         return -EFAULT;
 298         }
 299
 300         if (current->mm->context.vdso)
 301                 restorer = current->mm->context.vdso +
 302                         selected_vdso32->sym___kernel_sigreturn;
 303         else
 304                 restorer = &frame->retcode;
 305         if (ksig->ka.sa.sa_flags & SA_RESTORER)
 306                 restorer = ksig->ka.sa.sa_restorer;
 307
 308         /* Set up to return from userspace.  */
 309         err |= __put_user(restorer, &frame->pretcode);
 310
 311         /*
 312          * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
 313          *
 314          * WE DO NOT USE IT ANY MORE! It's only left here for historical
 315          * reasons and because gdb uses it as a signature to notice
 316          * signal handler stack frames.
 317          */
 318         err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
 319
 320         if (err)
 321                 return -EFAULT;
 322
 323         /* Set up registers for signal handler */
 324         regs->sp = (unsigned long)frame;
 325         regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
 326         regs->ax = (unsigned long)sig;
 327         regs->dx = 0;
 328         regs->cx = 0;
 329
 330         regs->ds = __USER_DS;
 331         regs->es = __USER_DS;
 332         regs->ss = __USER_DS;
 333         regs->cs = __USER_CS;
 334
 335         return 0;
 336 }
 337
 338 static int __setup_rt_frame(int sig, struct ksignal *ksig,
 339                             sigset_t *set, struct pt_regs *regs)
 340 {
 341         struct rt_sigframe __user *frame;
 342         void __user *restorer;
 343         int err = 0;
 344         void __user *fpstate = NULL;
 345
 346         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 347
 348         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 349                 return -EFAULT;
 350
 351         put_user_try {
 352                 put_user_ex(sig, &frame->sig);
 353                 put_user_ex(&frame->info, &frame->pinfo);
 354                 put_user_ex(&frame->uc, &frame->puc);
 355
 356                 /* Create the ucontext.  */
 357                 if (cpu_has_xsave)
 358                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 359                 else
 360                         put_user_ex(0, &frame->uc.uc_flags);
 361                 put_user_ex(0, &frame->uc.uc_link);
 362                 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 363
 364                 /* Set up to return from userspace.  */
 365                 restorer = current->mm->context.vdso +
 366                         selected_vdso32->sym___kernel_rt_sigreturn;
 367                 if (ksig->ka.sa.sa_flags & SA_RESTORER)
 368                         restorer = ksig->ka.sa.sa_restorer;
 369                 put_user_ex(restorer, &frame->pretcode);
 370
 371                 /*
 372                  * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
 373                  *
 374                  * WE DO NOT USE IT ANY MORE! It's only left here for historical
 375                  * reasons and because gdb uses it as a signature to notice
 376                  * signal handler stack frames.
 377                  */
 378                 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
 379         } put_user_catch(err);
 380
 381         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 382         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 383                                 regs, set->sig[0]);
 384         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 385
 386         if (err)
 387                 return -EFAULT;
 388
 389         /* Set up registers for signal handler */
 390         regs->sp = (unsigned long)frame;
 391         regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
 392         regs->ax = (unsigned long)sig;
 393         regs->dx = (unsigned long)&frame->info;
 394         regs->cx = (unsigned long)&frame->uc;
 395
 396         regs->ds = __USER_DS;
 397         regs->es = __USER_DS;
 398         regs->ss = __USER_DS;
 399         regs->cs = __USER_CS;
 400
 401         return 0;
 402 }
 403 #else /* !CONFIG_X86_32 */
 404 static int __setup_rt_frame(int sig, struct ksignal *ksig,
 405                             sigset_t *set, struct pt_regs *regs)
 406 {
 407         struct rt_sigframe __user *frame;
 408         void __user *fp = NULL;
 409         int err = 0;
 410
 411         frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
 412
 413         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 414                 return -EFAULT;
 415
 416         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 417                 if (copy_siginfo_to_user(&frame->info, &ksig->info))
 418                         return -EFAULT;
 419         }
 420
 421         put_user_try {
 422                 /* Create the ucontext.  */
 423                 if (cpu_has_xsave)
 424                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 425                 else
 426                         put_user_ex(0, &frame->uc.uc_flags);
 427                 put_user_ex(0, &frame->uc.uc_link);
 428                 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 429
 430                 /* Set up to return from userspace.  If provided, use a stub
 431                    already in userspace.  */
 432                 /* x86-64 should always use SA_RESTORER. */
 433                 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 434                         put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
 435                 } else {
 436                         /* could use a vstub here */
 437                         err |= -EFAULT;
 438                 }
 439         } put_user_catch(err);
 440
 441         err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
 442         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 443
 444         if (err)
 445                 return -EFAULT;
 446
 447         /* Set up registers for signal handler */
 448         regs->di = sig;
 449         /* In case the signal handler was declared without prototypes */
 450         regs->ax = 0;
 451
 452         /* This also works for non SA_SIGINFO handlers because they expect the
 453            next argument after the signal number on the stack. */
 454         regs->si = (unsigned long)&frame->info;
 455         regs->dx = (unsigned long)&frame->uc;
 456         regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
 457
 458         regs->sp = (unsigned long)frame;
 459
 460         /* Set up the CS register to run signal handlers in 64-bit mode,
 461            even if the handler happens to be interrupting 32-bit code. */
 462         regs->cs = __USER_CS;
 463
 464         return 0;
 465 }
 466 #endif /* CONFIG_X86_32 */
 467
 468 static int x32_setup_rt_frame(struct ksignal *ksig,
 469                               compat_sigset_t *set,
 470                               struct pt_regs *regs)
 471 {
 472 #ifdef CONFIG_X86_X32_ABI
 473         struct rt_sigframe_x32 __user *frame;
 474         void __user *restorer;
 475         int err = 0;
 476         void __user *fpstate = NULL;
 477
 478         frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 479
 480         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 481                 return -EFAULT;
 482
 483         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 484                 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
 485                         return -EFAULT;
 486         }
 487
 488         put_user_try {
 489                 /* Create the ucontext.  */
 490                 if (cpu_has_xsave)
 491                         put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 492                 else
 493                         put_user_ex(0, &frame->uc.uc_flags);
 494                 put_user_ex(0, &frame->uc.uc_link);
 495                 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 496                 put_user_ex(0, &frame->uc.uc__pad0);
 497
 498                 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 499                         restorer = ksig->ka.sa.sa_restorer;
 500                 } else {
 501                         /* could use a vstub here */
 502                         restorer = NULL;
 503                         err |= -EFAULT;
 504                 }
 505                 put_user_ex(restorer, &frame->pretcode);
 506         } put_user_catch(err);
 507
 508         err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
 509                                 regs, set->sig[0]);
 510         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 511
 512         if (err)
 513                 return -EFAULT;
 514
 515         /* Set up registers for signal handler */
 516         regs->sp = (unsigned long) frame;
 517         regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
 518
 519         /* We use the x32 calling convention here... */
 520         regs->di = ksig->sig;
 521         regs->si = (unsigned long) &frame->info;
 522         regs->dx = (unsigned long) &frame->uc;
 523
 524         loadsegment(ds, __USER_DS);
 525         loadsegment(es, __USER_DS);
 526
 527         regs->cs = __USER_CS;
 528         regs->ss = __USER_DS;
 529 #endif  /* CONFIG_X86_X32_ABI */
 530
 531         return 0;
 532 }
 533
 534 /*
 535  * Do a signal return; undo the signal stack.
 536  */
 537 #ifdef CONFIG_X86_32
 538 asmlinkage unsigned long sys_sigreturn(void)
 539 {
 540         struct pt_regs *regs = current_pt_regs();
 541         struct sigframe __user *frame;
 542         sigset_t set;
 543
 544         frame = (struct sigframe __user *)(regs->sp - 8);
 545
 546         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 547                 goto badframe;
 548         if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
 549                 && __copy_from_user(&set.sig[1], &frame->extramask,
 550                                     sizeof(frame->extramask))))
 551                 goto badframe;
 552
 553         set_current_blocked(&set);
 554
 555         if (restore_sigcontext(regs, &frame->sc))
 556                 goto badframe;
 557         return regs->ax;
 558
 559 badframe:
 560         signal_fault(regs, frame, "sigreturn");
 561
 562         return 0;
 563 }
 564 #endif /* CONFIG_X86_32 */
 565
 566 asmlinkage long sys_rt_sigreturn(void)
 567 {
 568         struct pt_regs *regs = current_pt_regs();
 569         struct rt_sigframe __user *frame;
 570         sigset_t set;
 571
 572         frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
 573         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 574                 goto badframe;
 575         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 576                 goto badframe;
 577
 578         set_current_blocked(&set);
 579
 580         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 581                 goto badframe;
 582
 583         if (restore_altstack(&frame->uc.uc_stack))
 584                 goto badframe;
 585
 586         return regs->ax;
 587
 588 badframe:
 589         signal_fault(regs, frame, "rt_sigreturn");
 590         return 0;
 591 }
 592
 593 static inline int is_ia32_compat_frame(void)
 594 {
 595         return config_enabled(CONFIG_IA32_EMULATION) &&
 596                test_thread_flag(TIF_IA32);
 597 }
 598
 599 static inline int is_ia32_frame(void)
 600 {
 601         return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame();
 602 }
 603
 604 static inline int is_x32_frame(void)
 605 {
 606         return config_enabled(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32);
 607 }
 608
 609 static int
 610 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
 611 {
 612         int usig = ksig->sig;
 613         sigset_t *set = sigmask_to_save();
 614         compat_sigset_t *cset = (compat_sigset_t *) set;
 615
 616         /* Set up the stack frame */
 617         if (is_ia32_frame()) {
 618                 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 619                         return ia32_setup_rt_frame(usig, ksig, cset, regs);
 620                 else
 621                         return ia32_setup_frame(usig, ksig, cset, regs);
 622         } else if (is_x32_frame()) {
 623                 return x32_setup_rt_frame(ksig, cset, regs);
 624         } else {
 625                 return __setup_rt_frame(ksig->sig, ksig, set, regs);
 626         }
 627 }
 628
 629 static void
 630 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 631 {
 632         bool stepping, failed;
 633         struct fpu *fpu = &current->thread.fpu;
 634
 635         /* Are we from a system call? */
 636         if (syscall_get_nr(current, regs) >= 0) {
 637                 /* If so, check system call restarting.. */
 638                 switch (syscall_get_error(current, regs)) {
 639                 case -ERESTART_RESTARTBLOCK:
 640                 case -ERESTARTNOHAND:
 641                         regs->ax = -EINTR;
 642                         break;
 643
 644                 case -ERESTARTSYS:
 645                         if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
 646                                 regs->ax = -EINTR;
 647                                 break;
 648                         }
 649                 /* fallthrough */
 650                 case -ERESTARTNOINTR:
 651                         regs->ax = regs->orig_ax;
 652                         regs->ip -= 2;
 653                         break;
 654                 }
 655         }
 656
 657         /*
 658          * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
 659          * so that register information in the sigcontext is correct and
 660          * then notify the tracer before entering the signal handler.
 661          */
 662         stepping = test_thread_flag(TIF_SINGLESTEP);
 663         if (stepping)
 664                 user_disable_single_step(current);
 665
 666         failed = (setup_rt_frame(ksig, regs) < 0);
 667         if (!failed) {
 668                 /*
 669                  * Clear the direction flag as per the ABI for function entry.
 670                  *
 671                  * Clear RF when entering the signal handler, because
 672                  * it might disable possible debug exception from the
 673                  * signal handler.
 674                  *
 675                  * Clear TF for the case when it wasn't set by debugger to
 676                  * avoid the recursive send_sigtrap() in SIGTRAP handler.
 677                  */
 678                 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
 679                 /*
 680                  * Ensure the signal handler starts with the new fpu state.
 681                  */
 682                 if (fpu->fpstate_active)
 683                         fpu__clear(fpu);
 684         }
 685         signal_setup_done(failed, ksig, stepping);
 686 }
 687
 688 #ifdef CONFIG_X86_32
 689 #define NR_restart_syscall      __NR_restart_syscall
 690 #else /* !CONFIG_X86_32 */
 691 #define NR_restart_syscall      \
 692         test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
 693 #endif /* CONFIG_X86_32 */
 694
 695 /*
 696  * Note that 'init' is a special process: it doesn't get signals it doesn't
 697  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 698  * mistake.
 699  */
 700 static void do_signal(struct pt_regs *regs)
 701 {
 702         struct ksignal ksig;
 703
 704         if (get_signal(&ksig)) {
 705                 /* Whee! Actually deliver the signal.  */
 706                 handle_signal(&ksig, regs);
 707                 return;
 708         }
 709
 710         /* Did we come from a system call? */
 711         if (syscall_get_nr(current, regs) >= 0) {
 712                 /* Restart the system call - no handlers present */
 713                 switch (syscall_get_error(current, regs)) {
 714                 case -ERESTARTNOHAND:
 715                 case -ERESTARTSYS:
 716                 case -ERESTARTNOINTR:
 717                         regs->ax = regs->orig_ax;
 718                         regs->ip -= 2;
 719                         break;
 720
 721                 case -ERESTART_RESTARTBLOCK:
 722                         regs->ax = NR_restart_syscall;
 723                         regs->ip -= 2;
 724                         break;
 725                 }
 726         }
 727
 728         /*
 729          * If there's no signal to deliver, we just put the saved sigmask
 730          * back.
 731          */
 732         restore_saved_sigmask();
 733 }
 734
 735 /*
 736  * notification of userspace execution resumption
 737  * - triggered by the TIF_WORK_MASK flags
 738  */
 739 __visible void
 740 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 741 {
 742         user_exit();
 743
 744         if (thread_info_flags & _TIF_UPROBE)
 745                 uprobe_notify_resume(regs);
 746
 747         /* deal with pending signal delivery */
 748         if (thread_info_flags & _TIF_SIGPENDING)
 749                 do_signal(regs);
 750
 751         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 752                 clear_thread_flag(TIF_NOTIFY_RESUME);
 753                 tracehook_notify_resume(regs);
 754         }
 755         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
 756                 fire_user_return_notifiers();
 757
 758         user_enter();
 759 }
 760
 761 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 762 {
 763         struct task_struct *me = current;
 764
 765         if (show_unhandled_signals && printk_ratelimit()) {
 766                 printk("%s"
 767                        "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
 768                        task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
 769                        me->comm, me->pid, where, frame,
 770                        regs->ip, regs->sp, regs->orig_ax);
 771                 print_vma_addr(" in ", regs->ip);
 772                 pr_cont("\n");
 773         }
 774
 775         force_sig(SIGSEGV, me);
 776 }
 777
 778 #ifdef CONFIG_X86_X32_ABI
 779 asmlinkage long sys32_x32_rt_sigreturn(void)
 780 {
 781         struct pt_regs *regs = current_pt_regs();
 782         struct rt_sigframe_x32 __user *frame;
 783         sigset_t set;
 784
 785         frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
 786
 787         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 788                 goto badframe;
 789         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 790                 goto badframe;
 791
 792         set_current_blocked(&set);
 793
 794         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 795                 goto badframe;
 796
 797         if (compat_restore_altstack(&frame->uc.uc_stack))
 798                 goto badframe;
 799
 800         return regs->ax;
 801
 802 badframe:
 803         signal_fault(regs, frame, "x32 rt_sigreturn");
 804         return 0;
 805 }
 806 #endif