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 #include <linux/sched.h> 10 #include <linux/mm.h> 11 #include <linux/smp.h> 12 #include <linux/kernel.h> 13 #include <linux/signal.h> 14 #include <linux/errno.h> 15 #include <linux/wait.h> 16 #include <linux/ptrace.h> 17 #include <linux/tracehook.h> 18 #include <linux/unistd.h> 19 #include <linux/stddef.h> 20 #include <linux/personality.h> 21 #include <linux/uaccess.h> 22 #include <linux/user-return-notifier.h> 23 24 #include <asm/processor.h> 25 #include <asm/ucontext.h> 26 #include <asm/i387.h> 27 #include <asm/vdso.h> 28 #include <asm/mce.h> 29 30 #ifdef CONFIG_X86_64 31 #include <asm/proto.h> 32 #include <asm/ia32_unistd.h> 33 #endif /* CONFIG_X86_64 */ 34 35 #include <asm/syscall.h> 36 #include <asm/syscalls.h> 37 38 #include <asm/sigframe.h> 39 40 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 41 42 #define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \ 43 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \ 44 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \ 45 X86_EFLAGS_CF) 46 47 #ifdef CONFIG_X86_32 48 # define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF) 49 #else 50 # define FIX_EFLAGS __FIX_EFLAGS 51 #endif 52 53 #define COPY(x) do { \ 54 get_user_ex(regs->x, &sc->x); \ 55 } while (0) 56 57 #define GET_SEG(seg) ({ \ 58 unsigned short tmp; \ 59 get_user_ex(tmp, &sc->seg); \ 60 tmp; \ 61 }) 62 63 #define COPY_SEG(seg) do { \ 64 regs->seg = GET_SEG(seg); \ 65 } while (0) 66 67 #define COPY_SEG_CPL3(seg) do { \ 68 regs->seg = GET_SEG(seg) | 3; \ 69 } while (0) 70 71 static int 72 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, 73 unsigned long *pax) 74 { 75 void __user *buf; 76 unsigned int tmpflags; 77 unsigned int err = 0; 78 79 /* Always make any pending restarted system calls return -EINTR */ 80 current_thread_info()->restart_block.fn = do_no_restart_syscall; 81 82 get_user_try { 83 84 #ifdef CONFIG_X86_32 85 set_user_gs(regs, GET_SEG(gs)); 86 COPY_SEG(fs); 87 COPY_SEG(es); 88 COPY_SEG(ds); 89 #endif /* CONFIG_X86_32 */ 90 91 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); 92 COPY(dx); COPY(cx); COPY(ip); 93 94 #ifdef CONFIG_X86_64 95 COPY(r8); 96 COPY(r9); 97 COPY(r10); 98 COPY(r11); 99 COPY(r12); 100 COPY(r13); 101 COPY(r14); 102 COPY(r15); 103 #endif /* CONFIG_X86_64 */ 104 105 #ifdef CONFIG_X86_32 106 COPY_SEG_CPL3(cs); 107 COPY_SEG_CPL3(ss); 108 #else /* !CONFIG_X86_32 */ 109 /* Kernel saves and restores only the CS segment register on signals, 110 * which is the bare minimum needed to allow mixed 32/64-bit code. 111 * App's signal handler can save/restore other segments if needed. */ 112 COPY_SEG_CPL3(cs); 113 #endif /* CONFIG_X86_32 */ 114 115 get_user_ex(tmpflags, &sc->flags); 116 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); 117 regs->orig_ax = -1; /* disable syscall checks */ 118 119 get_user_ex(buf, &sc->fpstate); 120 err |= restore_i387_xstate(buf); 121 122 get_user_ex(*pax, &sc->ax); 123 } get_user_catch(err); 124 125 return err; 126 } 127 128 static int 129 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, 130 struct pt_regs *regs, unsigned long mask) 131 { 132 int err = 0; 133 134 put_user_try { 135 136 #ifdef CONFIG_X86_32 137 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); 138 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); 139 put_user_ex(regs->es, (unsigned int __user *)&sc->es); 140 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); 141 #endif /* CONFIG_X86_32 */ 142 143 put_user_ex(regs->di, &sc->di); 144 put_user_ex(regs->si, &sc->si); 145 put_user_ex(regs->bp, &sc->bp); 146 put_user_ex(regs->sp, &sc->sp); 147 put_user_ex(regs->bx, &sc->bx); 148 put_user_ex(regs->dx, &sc->dx); 149 put_user_ex(regs->cx, &sc->cx); 150 put_user_ex(regs->ax, &sc->ax); 151 #ifdef CONFIG_X86_64 152 put_user_ex(regs->r8, &sc->r8); 153 put_user_ex(regs->r9, &sc->r9); 154 put_user_ex(regs->r10, &sc->r10); 155 put_user_ex(regs->r11, &sc->r11); 156 put_user_ex(regs->r12, &sc->r12); 157 put_user_ex(regs->r13, &sc->r13); 158 put_user_ex(regs->r14, &sc->r14); 159 put_user_ex(regs->r15, &sc->r15); 160 #endif /* CONFIG_X86_64 */ 161 162 put_user_ex(current->thread.trap_no, &sc->trapno); 163 put_user_ex(current->thread.error_code, &sc->err); 164 put_user_ex(regs->ip, &sc->ip); 165 #ifdef CONFIG_X86_32 166 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); 167 put_user_ex(regs->flags, &sc->flags); 168 put_user_ex(regs->sp, &sc->sp_at_signal); 169 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); 170 #else /* !CONFIG_X86_32 */ 171 put_user_ex(regs->flags, &sc->flags); 172 put_user_ex(regs->cs, &sc->cs); 173 put_user_ex(0, &sc->gs); 174 put_user_ex(0, &sc->fs); 175 #endif /* CONFIG_X86_32 */ 176 177 put_user_ex(fpstate, &sc->fpstate); 178 179 /* non-iBCS2 extensions.. */ 180 put_user_ex(mask, &sc->oldmask); 181 put_user_ex(current->thread.cr2, &sc->cr2); 182 } put_user_catch(err); 183 184 return err; 185 } 186 187 /* 188 * Set up a signal frame. 189 */ 190 191 /* 192 * Determine which stack to use.. 193 */ 194 static unsigned long align_sigframe(unsigned long sp) 195 { 196 #ifdef CONFIG_X86_32 197 /* 198 * Align the stack pointer according to the i386 ABI, 199 * i.e. so that on function entry ((sp + 4) & 15) == 0. 200 */ 201 sp = ((sp + 4) & -16ul) - 4; 202 #else /* !CONFIG_X86_32 */ 203 sp = round_down(sp, 16) - 8; 204 #endif 205 return sp; 206 } 207 208 static inline void __user * 209 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 210 void __user **fpstate) 211 { 212 /* Default to using normal stack */ 213 unsigned long sp = regs->sp; 214 int onsigstack = on_sig_stack(sp); 215 216 #ifdef CONFIG_X86_64 217 /* redzone */ 218 sp -= 128; 219 #endif /* CONFIG_X86_64 */ 220 221 if (!onsigstack) { 222 /* This is the X/Open sanctioned signal stack switching. */ 223 if (ka->sa.sa_flags & SA_ONSTACK) { 224 if (current->sas_ss_size) 225 sp = current->sas_ss_sp + current->sas_ss_size; 226 } else { 227 #ifdef CONFIG_X86_32 228 /* This is the legacy signal stack switching. */ 229 if ((regs->ss & 0xffff) != __USER_DS && 230 !(ka->sa.sa_flags & SA_RESTORER) && 231 ka->sa.sa_restorer) 232 sp = (unsigned long) ka->sa.sa_restorer; 233 #endif /* CONFIG_X86_32 */ 234 } 235 } 236 237 if (used_math()) { 238 sp -= sig_xstate_size; 239 #ifdef CONFIG_X86_64 240 sp = round_down(sp, 64); 241 #endif /* CONFIG_X86_64 */ 242 *fpstate = (void __user *)sp; 243 } 244 245 sp = align_sigframe(sp - frame_size); 246 247 /* 248 * If we are on the alternate signal stack and would overflow it, don't. 249 * Return an always-bogus address instead so we will die with SIGSEGV. 250 */ 251 if (onsigstack && !likely(on_sig_stack(sp))) 252 return (void __user *)-1L; 253 254 /* save i387 state */ 255 if (used_math() && save_i387_xstate(*fpstate) < 0) 256 return (void __user *)-1L; 257 258 return (void __user *)sp; 259 } 260 261 #ifdef CONFIG_X86_32 262 static const struct { 263 u16 poplmovl; 264 u32 val; 265 u16 int80; 266 } __attribute__((packed)) retcode = { 267 0xb858, /* popl %eax; movl $..., %eax */ 268 __NR_sigreturn, 269 0x80cd, /* int $0x80 */ 270 }; 271 272 static const struct { 273 u8 movl; 274 u32 val; 275 u16 int80; 276 u8 pad; 277 } __attribute__((packed)) rt_retcode = { 278 0xb8, /* movl $..., %eax */ 279 __NR_rt_sigreturn, 280 0x80cd, /* int $0x80 */ 281 0 282 }; 283 284 static int 285 __setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, 286 struct pt_regs *regs) 287 { 288 struct sigframe __user *frame; 289 void __user *restorer; 290 int err = 0; 291 void __user *fpstate = NULL; 292 293 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate); 294 295 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 296 return -EFAULT; 297 298 if (__put_user(sig, &frame->sig)) 299 return -EFAULT; 300 301 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) 302 return -EFAULT; 303 304 if (_NSIG_WORDS > 1) { 305 if (__copy_to_user(&frame->extramask, &set->sig[1], 306 sizeof(frame->extramask))) 307 return -EFAULT; 308 } 309 310 if (current->mm->context.vdso) 311 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn); 312 else 313 restorer = &frame->retcode; 314 if (ka->sa.sa_flags & SA_RESTORER) 315 restorer = ka->sa.sa_restorer; 316 317 /* Set up to return from userspace. */ 318 err |= __put_user(restorer, &frame->pretcode); 319 320 /* 321 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 322 * 323 * WE DO NOT USE IT ANY MORE! It's only left here for historical 324 * reasons and because gdb uses it as a signature to notice 325 * signal handler stack frames. 326 */ 327 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); 328 329 if (err) 330 return -EFAULT; 331 332 /* Set up registers for signal handler */ 333 regs->sp = (unsigned long)frame; 334 regs->ip = (unsigned long)ka->sa.sa_handler; 335 regs->ax = (unsigned long)sig; 336 regs->dx = 0; 337 regs->cx = 0; 338 339 regs->ds = __USER_DS; 340 regs->es = __USER_DS; 341 regs->ss = __USER_DS; 342 regs->cs = __USER_CS; 343 344 return 0; 345 } 346 347 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 348 sigset_t *set, struct pt_regs *regs) 349 { 350 struct rt_sigframe __user *frame; 351 void __user *restorer; 352 int err = 0; 353 void __user *fpstate = NULL; 354 355 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate); 356 357 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 358 return -EFAULT; 359 360 put_user_try { 361 put_user_ex(sig, &frame->sig); 362 put_user_ex(&frame->info, &frame->pinfo); 363 put_user_ex(&frame->uc, &frame->puc); 364 err |= copy_siginfo_to_user(&frame->info, info); 365 366 /* Create the ucontext. */ 367 if (cpu_has_xsave) 368 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 369 else 370 put_user_ex(0, &frame->uc.uc_flags); 371 put_user_ex(0, &frame->uc.uc_link); 372 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); 373 put_user_ex(sas_ss_flags(regs->sp), 374 &frame->uc.uc_stack.ss_flags); 375 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 376 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, 377 regs, set->sig[0]); 378 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 379 380 /* Set up to return from userspace. */ 381 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn); 382 if (ka->sa.sa_flags & SA_RESTORER) 383 restorer = ka->sa.sa_restorer; 384 put_user_ex(restorer, &frame->pretcode); 385 386 /* 387 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 388 * 389 * WE DO NOT USE IT ANY MORE! It's only left here for historical 390 * reasons and because gdb uses it as a signature to notice 391 * signal handler stack frames. 392 */ 393 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); 394 } put_user_catch(err); 395 396 if (err) 397 return -EFAULT; 398 399 /* Set up registers for signal handler */ 400 regs->sp = (unsigned long)frame; 401 regs->ip = (unsigned long)ka->sa.sa_handler; 402 regs->ax = (unsigned long)sig; 403 regs->dx = (unsigned long)&frame->info; 404 regs->cx = (unsigned long)&frame->uc; 405 406 regs->ds = __USER_DS; 407 regs->es = __USER_DS; 408 regs->ss = __USER_DS; 409 regs->cs = __USER_CS; 410 411 return 0; 412 } 413 #else /* !CONFIG_X86_32 */ 414 static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 415 sigset_t *set, struct pt_regs *regs) 416 { 417 struct rt_sigframe __user *frame; 418 void __user *fp = NULL; 419 int err = 0; 420 struct task_struct *me = current; 421 422 frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp); 423 424 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 425 return -EFAULT; 426 427 if (ka->sa.sa_flags & SA_SIGINFO) { 428 if (copy_siginfo_to_user(&frame->info, info)) 429 return -EFAULT; 430 } 431 432 put_user_try { 433 /* Create the ucontext. */ 434 if (cpu_has_xsave) 435 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 436 else 437 put_user_ex(0, &frame->uc.uc_flags); 438 put_user_ex(0, &frame->uc.uc_link); 439 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp); 440 put_user_ex(sas_ss_flags(regs->sp), 441 &frame->uc.uc_stack.ss_flags); 442 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size); 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 /* Set up to return from userspace. If provided, use a stub 447 already in userspace. */ 448 /* x86-64 should always use SA_RESTORER. */ 449 if (ka->sa.sa_flags & SA_RESTORER) { 450 put_user_ex(ka->sa.sa_restorer, &frame->pretcode); 451 } else { 452 /* could use a vstub here */ 453 err |= -EFAULT; 454 } 455 } put_user_catch(err); 456 457 if (err) 458 return -EFAULT; 459 460 /* Set up registers for signal handler */ 461 regs->di = sig; 462 /* In case the signal handler was declared without prototypes */ 463 regs->ax = 0; 464 465 /* This also works for non SA_SIGINFO handlers because they expect the 466 next argument after the signal number on the stack. */ 467 regs->si = (unsigned long)&frame->info; 468 regs->dx = (unsigned long)&frame->uc; 469 regs->ip = (unsigned long) ka->sa.sa_handler; 470 471 regs->sp = (unsigned long)frame; 472 473 /* Set up the CS register to run signal handlers in 64-bit mode, 474 even if the handler happens to be interrupting 32-bit code. */ 475 regs->cs = __USER_CS; 476 477 return 0; 478 } 479 #endif /* CONFIG_X86_32 */ 480 481 #ifdef CONFIG_X86_32 482 /* 483 * Atomically swap in the new signal mask, and wait for a signal. 484 */ 485 asmlinkage int 486 sys_sigsuspend(int history0, int history1, old_sigset_t mask) 487 { 488 mask &= _BLOCKABLE; 489 spin_lock_irq(¤t->sighand->siglock); 490 current->saved_sigmask = current->blocked; 491 siginitset(¤t->blocked, mask); 492 recalc_sigpending(); 493 spin_unlock_irq(¤t->sighand->siglock); 494 495 current->state = TASK_INTERRUPTIBLE; 496 schedule(); 497 set_restore_sigmask(); 498 499 return -ERESTARTNOHAND; 500 } 501 502 asmlinkage int 503 sys_sigaction(int sig, const struct old_sigaction __user *act, 504 struct old_sigaction __user *oact) 505 { 506 struct k_sigaction new_ka, old_ka; 507 int ret = 0; 508 509 if (act) { 510 old_sigset_t mask; 511 512 if (!access_ok(VERIFY_READ, act, sizeof(*act))) 513 return -EFAULT; 514 515 get_user_try { 516 get_user_ex(new_ka.sa.sa_handler, &act->sa_handler); 517 get_user_ex(new_ka.sa.sa_flags, &act->sa_flags); 518 get_user_ex(mask, &act->sa_mask); 519 get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer); 520 } get_user_catch(ret); 521 522 if (ret) 523 return -EFAULT; 524 siginitset(&new_ka.sa.sa_mask, mask); 525 } 526 527 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 528 529 if (!ret && oact) { 530 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact))) 531 return -EFAULT; 532 533 put_user_try { 534 put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler); 535 put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags); 536 put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 537 put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer); 538 } put_user_catch(ret); 539 540 if (ret) 541 return -EFAULT; 542 } 543 544 return ret; 545 } 546 #endif /* CONFIG_X86_32 */ 547 548 long 549 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 550 struct pt_regs *regs) 551 { 552 return do_sigaltstack(uss, uoss, regs->sp); 553 } 554 555 /* 556 * Do a signal return; undo the signal stack. 557 */ 558 #ifdef CONFIG_X86_32 559 unsigned long sys_sigreturn(struct pt_regs *regs) 560 { 561 struct sigframe __user *frame; 562 unsigned long ax; 563 sigset_t set; 564 565 frame = (struct sigframe __user *)(regs->sp - 8); 566 567 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 568 goto badframe; 569 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 570 && __copy_from_user(&set.sig[1], &frame->extramask, 571 sizeof(frame->extramask)))) 572 goto badframe; 573 574 sigdelsetmask(&set, ~_BLOCKABLE); 575 spin_lock_irq(¤t->sighand->siglock); 576 current->blocked = set; 577 recalc_sigpending(); 578 spin_unlock_irq(¤t->sighand->siglock); 579 580 if (restore_sigcontext(regs, &frame->sc, &ax)) 581 goto badframe; 582 return ax; 583 584 badframe: 585 signal_fault(regs, frame, "sigreturn"); 586 587 return 0; 588 } 589 #endif /* CONFIG_X86_32 */ 590 591 long sys_rt_sigreturn(struct pt_regs *regs) 592 { 593 struct rt_sigframe __user *frame; 594 unsigned long ax; 595 sigset_t set; 596 597 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); 598 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 599 goto badframe; 600 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 601 goto badframe; 602 603 sigdelsetmask(&set, ~_BLOCKABLE); 604 set_current_blocked(&set); 605 606 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax)) 607 goto badframe; 608 609 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT) 610 goto badframe; 611 612 return ax; 613 614 badframe: 615 signal_fault(regs, frame, "rt_sigreturn"); 616 return 0; 617 } 618 619 /* 620 * OK, we're invoking a handler: 621 */ 622 static int signr_convert(int sig) 623 { 624 #ifdef CONFIG_X86_32 625 struct thread_info *info = current_thread_info(); 626 627 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32) 628 return info->exec_domain->signal_invmap[sig]; 629 #endif /* CONFIG_X86_32 */ 630 return sig; 631 } 632 633 #ifdef CONFIG_X86_32 634 635 #define is_ia32 1 636 #define ia32_setup_frame __setup_frame 637 #define ia32_setup_rt_frame __setup_rt_frame 638 639 #else /* !CONFIG_X86_32 */ 640 641 #ifdef CONFIG_IA32_EMULATION 642 #define is_ia32 test_thread_flag(TIF_IA32) 643 #else /* !CONFIG_IA32_EMULATION */ 644 #define is_ia32 0 645 #endif /* CONFIG_IA32_EMULATION */ 646 647 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 648 sigset_t *set, struct pt_regs *regs); 649 int ia32_setup_frame(int sig, struct k_sigaction *ka, 650 sigset_t *set, struct pt_regs *regs); 651 652 #endif /* CONFIG_X86_32 */ 653 654 static int 655 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 656 sigset_t *set, struct pt_regs *regs) 657 { 658 int usig = signr_convert(sig); 659 int ret; 660 661 /* Set up the stack frame */ 662 if (is_ia32) { 663 if (ka->sa.sa_flags & SA_SIGINFO) 664 ret = ia32_setup_rt_frame(usig, ka, info, set, regs); 665 else 666 ret = ia32_setup_frame(usig, ka, set, regs); 667 } else 668 ret = __setup_rt_frame(sig, ka, info, set, regs); 669 670 if (ret) { 671 force_sigsegv(sig, current); 672 return -EFAULT; 673 } 674 675 return ret; 676 } 677 678 static int 679 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, 680 sigset_t *oldset, struct pt_regs *regs) 681 { 682 sigset_t blocked; 683 int ret; 684 685 /* Are we from a system call? */ 686 if (syscall_get_nr(current, regs) >= 0) { 687 /* If so, check system call restarting.. */ 688 switch (syscall_get_error(current, regs)) { 689 case -ERESTART_RESTARTBLOCK: 690 case -ERESTARTNOHAND: 691 regs->ax = -EINTR; 692 break; 693 694 case -ERESTARTSYS: 695 if (!(ka->sa.sa_flags & SA_RESTART)) { 696 regs->ax = -EINTR; 697 break; 698 } 699 /* fallthrough */ 700 case -ERESTARTNOINTR: 701 regs->ax = regs->orig_ax; 702 regs->ip -= 2; 703 break; 704 } 705 } 706 707 /* 708 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF 709 * flag so that register information in the sigcontext is correct. 710 */ 711 if (unlikely(regs->flags & X86_EFLAGS_TF) && 712 likely(test_and_clear_thread_flag(TIF_FORCED_TF))) 713 regs->flags &= ~X86_EFLAGS_TF; 714 715 ret = setup_rt_frame(sig, ka, info, oldset, regs); 716 717 if (ret) 718 return ret; 719 720 #ifdef CONFIG_X86_64 721 /* 722 * This has nothing to do with segment registers, 723 * despite the name. This magic affects uaccess.h 724 * macros' behavior. Reset it to the normal setting. 725 */ 726 set_fs(USER_DS); 727 #endif 728 729 /* 730 * Clear the direction flag as per the ABI for function entry. 731 */ 732 regs->flags &= ~X86_EFLAGS_DF; 733 734 /* 735 * Clear TF when entering the signal handler, but 736 * notify any tracer that was single-stepping it. 737 * The tracer may want to single-step inside the 738 * handler too. 739 */ 740 regs->flags &= ~X86_EFLAGS_TF; 741 742 sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask); 743 if (!(ka->sa.sa_flags & SA_NODEFER)) 744 sigaddset(&blocked, sig); 745 set_current_blocked(&blocked); 746 747 tracehook_signal_handler(sig, info, ka, regs, 748 test_thread_flag(TIF_SINGLESTEP)); 749 750 return 0; 751 } 752 753 #ifdef CONFIG_X86_32 754 #define NR_restart_syscall __NR_restart_syscall 755 #else /* !CONFIG_X86_32 */ 756 #define NR_restart_syscall \ 757 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall 758 #endif /* CONFIG_X86_32 */ 759 760 /* 761 * Note that 'init' is a special process: it doesn't get signals it doesn't 762 * want to handle. Thus you cannot kill init even with a SIGKILL even by 763 * mistake. 764 */ 765 static void do_signal(struct pt_regs *regs) 766 { 767 struct k_sigaction ka; 768 siginfo_t info; 769 int signr; 770 sigset_t *oldset; 771 772 /* 773 * We want the common case to go fast, which is why we may in certain 774 * cases get here from kernel mode. Just return without doing anything 775 * if so. 776 * X86_32: vm86 regs switched out by assembly code before reaching 777 * here, so testing against kernel CS suffices. 778 */ 779 if (!user_mode(regs)) 780 return; 781 782 if (current_thread_info()->status & TS_RESTORE_SIGMASK) 783 oldset = ¤t->saved_sigmask; 784 else 785 oldset = ¤t->blocked; 786 787 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 788 if (signr > 0) { 789 /* Whee! Actually deliver the signal. */ 790 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { 791 /* 792 * A signal was successfully delivered; the saved 793 * sigmask will have been stored in the signal frame, 794 * and will be restored by sigreturn, so we can simply 795 * clear the TS_RESTORE_SIGMASK flag. 796 */ 797 current_thread_info()->status &= ~TS_RESTORE_SIGMASK; 798 } 799 return; 800 } 801 802 /* Did we come from a system call? */ 803 if (syscall_get_nr(current, regs) >= 0) { 804 /* Restart the system call - no handlers present */ 805 switch (syscall_get_error(current, regs)) { 806 case -ERESTARTNOHAND: 807 case -ERESTARTSYS: 808 case -ERESTARTNOINTR: 809 regs->ax = regs->orig_ax; 810 regs->ip -= 2; 811 break; 812 813 case -ERESTART_RESTARTBLOCK: 814 regs->ax = NR_restart_syscall; 815 regs->ip -= 2; 816 break; 817 } 818 } 819 820 /* 821 * If there's no signal to deliver, we just put the saved sigmask 822 * back. 823 */ 824 if (current_thread_info()->status & TS_RESTORE_SIGMASK) { 825 current_thread_info()->status &= ~TS_RESTORE_SIGMASK; 826 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 827 } 828 } 829 830 /* 831 * notification of userspace execution resumption 832 * - triggered by the TIF_WORK_MASK flags 833 */ 834 void 835 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) 836 { 837 #ifdef CONFIG_X86_MCE 838 /* notify userspace of pending MCEs */ 839 if (thread_info_flags & _TIF_MCE_NOTIFY) 840 mce_notify_process(); 841 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */ 842 843 /* deal with pending signal delivery */ 844 if (thread_info_flags & _TIF_SIGPENDING) 845 do_signal(regs); 846 847 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 848 clear_thread_flag(TIF_NOTIFY_RESUME); 849 tracehook_notify_resume(regs); 850 if (current->replacement_session_keyring) 851 key_replace_session_keyring(); 852 } 853 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY) 854 fire_user_return_notifiers(); 855 856 #ifdef CONFIG_X86_32 857 clear_thread_flag(TIF_IRET); 858 #endif /* CONFIG_X86_32 */ 859 } 860 861 void signal_fault(struct pt_regs *regs, void __user *frame, char *where) 862 { 863 struct task_struct *me = current; 864 865 if (show_unhandled_signals && printk_ratelimit()) { 866 printk("%s" 867 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", 868 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, 869 me->comm, me->pid, where, frame, 870 regs->ip, regs->sp, regs->orig_ax); 871 print_vma_addr(" in ", regs->ip); 872 printk(KERN_CONT "\n"); 873 } 874 875 force_sig(SIGSEGV, me); 876 } 877