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/i387.h> 30 #include <asm/fpu-internal.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 unsigned long *pax) 66 { 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_thread_info()->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); 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, &sc->fpstate); 112 113 get_user_ex(*pax, &sc->ax); 114 } get_user_catch(err); 115 116 err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32)); 117 118 return err; 119 } 120 121 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, 122 struct pt_regs *regs, unsigned long mask) 123 { 124 int err = 0; 125 126 put_user_try { 127 128 #ifdef CONFIG_X86_32 129 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); 130 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); 131 put_user_ex(regs->es, (unsigned int __user *)&sc->es); 132 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); 133 #endif /* CONFIG_X86_32 */ 134 135 put_user_ex(regs->di, &sc->di); 136 put_user_ex(regs->si, &sc->si); 137 put_user_ex(regs->bp, &sc->bp); 138 put_user_ex(regs->sp, &sc->sp); 139 put_user_ex(regs->bx, &sc->bx); 140 put_user_ex(regs->dx, &sc->dx); 141 put_user_ex(regs->cx, &sc->cx); 142 put_user_ex(regs->ax, &sc->ax); 143 #ifdef CONFIG_X86_64 144 put_user_ex(regs->r8, &sc->r8); 145 put_user_ex(regs->r9, &sc->r9); 146 put_user_ex(regs->r10, &sc->r10); 147 put_user_ex(regs->r11, &sc->r11); 148 put_user_ex(regs->r12, &sc->r12); 149 put_user_ex(regs->r13, &sc->r13); 150 put_user_ex(regs->r14, &sc->r14); 151 put_user_ex(regs->r15, &sc->r15); 152 #endif /* CONFIG_X86_64 */ 153 154 put_user_ex(current->thread.trap_nr, &sc->trapno); 155 put_user_ex(current->thread.error_code, &sc->err); 156 put_user_ex(regs->ip, &sc->ip); 157 #ifdef CONFIG_X86_32 158 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); 159 put_user_ex(regs->flags, &sc->flags); 160 put_user_ex(regs->sp, &sc->sp_at_signal); 161 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); 162 #else /* !CONFIG_X86_32 */ 163 put_user_ex(regs->flags, &sc->flags); 164 put_user_ex(regs->cs, &sc->cs); 165 put_user_ex(0, &sc->gs); 166 put_user_ex(0, &sc->fs); 167 #endif /* CONFIG_X86_32 */ 168 169 put_user_ex(fpstate, &sc->fpstate); 170 171 /* non-iBCS2 extensions.. */ 172 put_user_ex(mask, &sc->oldmask); 173 put_user_ex(current->thread.cr2, &sc->cr2); 174 } put_user_catch(err); 175 176 return err; 177 } 178 179 /* 180 * Set up a signal frame. 181 */ 182 183 /* 184 * Determine which stack to use.. 185 */ 186 static unsigned long align_sigframe(unsigned long sp) 187 { 188 #ifdef CONFIG_X86_32 189 /* 190 * Align the stack pointer according to the i386 ABI, 191 * i.e. so that on function entry ((sp + 4) & 15) == 0. 192 */ 193 sp = ((sp + 4) & -16ul) - 4; 194 #else /* !CONFIG_X86_32 */ 195 sp = round_down(sp, 16) - 8; 196 #endif 197 return sp; 198 } 199 200 static inline void __user * 201 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 202 void __user **fpstate) 203 { 204 /* Default to using normal stack */ 205 unsigned long math_size = 0; 206 unsigned long sp = regs->sp; 207 unsigned long buf_fx = 0; 208 int onsigstack = on_sig_stack(sp); 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 (used_math()) { 229 sp = 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 (used_math() && 245 save_xstate_sig(*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 unsigned long ax; 543 sigset_t set; 544 545 frame = (struct sigframe __user *)(regs->sp - 8); 546 547 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 548 goto badframe; 549 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 550 && __copy_from_user(&set.sig[1], &frame->extramask, 551 sizeof(frame->extramask)))) 552 goto badframe; 553 554 set_current_blocked(&set); 555 556 if (restore_sigcontext(regs, &frame->sc, &ax)) 557 goto badframe; 558 return ax; 559 560 badframe: 561 signal_fault(regs, frame, "sigreturn"); 562 563 return 0; 564 } 565 #endif /* CONFIG_X86_32 */ 566 567 asmlinkage long sys_rt_sigreturn(void) 568 { 569 struct pt_regs *regs = current_pt_regs(); 570 struct rt_sigframe __user *frame; 571 unsigned long ax; 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, &ax)) 583 goto badframe; 584 585 if (restore_altstack(&frame->uc.uc_stack)) 586 goto badframe; 587 588 return ax; 589 590 badframe: 591 signal_fault(regs, frame, "rt_sigreturn"); 592 return 0; 593 } 594 595 /* 596 * OK, we're invoking a handler: 597 */ 598 static int signr_convert(int sig) 599 { 600 #ifdef CONFIG_X86_32 601 struct thread_info *info = current_thread_info(); 602 603 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32) 604 return info->exec_domain->signal_invmap[sig]; 605 #endif /* CONFIG_X86_32 */ 606 return sig; 607 } 608 609 static int 610 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 611 { 612 int usig = signr_convert(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 failed; 633 /* Are we from a system call? */ 634 if (syscall_get_nr(current, regs) >= 0) { 635 /* If so, check system call restarting.. */ 636 switch (syscall_get_error(current, regs)) { 637 case -ERESTART_RESTARTBLOCK: 638 case -ERESTARTNOHAND: 639 regs->ax = -EINTR; 640 break; 641 642 case -ERESTARTSYS: 643 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 644 regs->ax = -EINTR; 645 break; 646 } 647 /* fallthrough */ 648 case -ERESTARTNOINTR: 649 regs->ax = regs->orig_ax; 650 regs->ip -= 2; 651 break; 652 } 653 } 654 655 /* 656 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF 657 * flag so that register information in the sigcontext is correct. 658 */ 659 if (unlikely(regs->flags & X86_EFLAGS_TF) && 660 likely(test_and_clear_thread_flag(TIF_FORCED_TF))) 661 regs->flags &= ~X86_EFLAGS_TF; 662 663 failed = (setup_rt_frame(ksig, regs) < 0); 664 if (!failed) { 665 /* 666 * Clear the direction flag as per the ABI for function entry. 667 * 668 * Clear RF when entering the signal handler, because 669 * it might disable possible debug exception from the 670 * signal handler. 671 * 672 * Clear TF when entering the signal handler, but 673 * notify any tracer that was single-stepping it. 674 * The tracer may want to single-step inside the 675 * handler too. 676 */ 677 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); 678 } 679 signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP)); 680 } 681 682 #ifdef CONFIG_X86_32 683 #define NR_restart_syscall __NR_restart_syscall 684 #else /* !CONFIG_X86_32 */ 685 #define NR_restart_syscall \ 686 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall 687 #endif /* CONFIG_X86_32 */ 688 689 /* 690 * Note that 'init' is a special process: it doesn't get signals it doesn't 691 * want to handle. Thus you cannot kill init even with a SIGKILL even by 692 * mistake. 693 */ 694 static void do_signal(struct pt_regs *regs) 695 { 696 struct ksignal ksig; 697 698 if (get_signal(&ksig)) { 699 /* Whee! Actually deliver the signal. */ 700 handle_signal(&ksig, regs); 701 return; 702 } 703 704 /* Did we come from a system call? */ 705 if (syscall_get_nr(current, regs) >= 0) { 706 /* Restart the system call - no handlers present */ 707 switch (syscall_get_error(current, regs)) { 708 case -ERESTARTNOHAND: 709 case -ERESTARTSYS: 710 case -ERESTARTNOINTR: 711 regs->ax = regs->orig_ax; 712 regs->ip -= 2; 713 break; 714 715 case -ERESTART_RESTARTBLOCK: 716 regs->ax = NR_restart_syscall; 717 regs->ip -= 2; 718 break; 719 } 720 } 721 722 /* 723 * If there's no signal to deliver, we just put the saved sigmask 724 * back. 725 */ 726 restore_saved_sigmask(); 727 } 728 729 /* 730 * notification of userspace execution resumption 731 * - triggered by the TIF_WORK_MASK flags 732 */ 733 __visible void 734 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) 735 { 736 user_exit(); 737 738 #ifdef CONFIG_X86_MCE 739 /* notify userspace of pending MCEs */ 740 if (thread_info_flags & _TIF_MCE_NOTIFY) 741 mce_notify_process(); 742 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */ 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 unsigned long ax; 785 786 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); 787 788 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 789 goto badframe; 790 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 791 goto badframe; 792 793 set_current_blocked(&set); 794 795 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax)) 796 goto badframe; 797 798 if (compat_restore_altstack(&frame->uc.uc_stack)) 799 goto badframe; 800 801 return ax; 802 803 badframe: 804 signal_fault(regs, frame, "x32 rt_sigreturn"); 805 return 0; 806 } 807 #endif 808