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 = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn); 302 else 303 restorer = &frame->retcode; 304 if (ksig->ka.sa.sa_flags & SA_RESTORER) 305 restorer = ksig->ka.sa.sa_restorer; 306 307 /* Set up to return from userspace. */ 308 err |= __put_user(restorer, &frame->pretcode); 309 310 /* 311 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 312 * 313 * WE DO NOT USE IT ANY MORE! It's only left here for historical 314 * reasons and because gdb uses it as a signature to notice 315 * signal handler stack frames. 316 */ 317 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); 318 319 if (err) 320 return -EFAULT; 321 322 /* Set up registers for signal handler */ 323 regs->sp = (unsigned long)frame; 324 regs->ip = (unsigned long)ksig->ka.sa.sa_handler; 325 regs->ax = (unsigned long)sig; 326 regs->dx = 0; 327 regs->cx = 0; 328 329 regs->ds = __USER_DS; 330 regs->es = __USER_DS; 331 regs->ss = __USER_DS; 332 regs->cs = __USER_CS; 333 334 return 0; 335 } 336 337 static int __setup_rt_frame(int sig, struct ksignal *ksig, 338 sigset_t *set, struct pt_regs *regs) 339 { 340 struct rt_sigframe __user *frame; 341 void __user *restorer; 342 int err = 0; 343 void __user *fpstate = NULL; 344 345 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 346 347 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 348 return -EFAULT; 349 350 put_user_try { 351 put_user_ex(sig, &frame->sig); 352 put_user_ex(&frame->info, &frame->pinfo); 353 put_user_ex(&frame->uc, &frame->puc); 354 355 /* Create the ucontext. */ 356 if (cpu_has_xsave) 357 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 358 else 359 put_user_ex(0, &frame->uc.uc_flags); 360 put_user_ex(0, &frame->uc.uc_link); 361 save_altstack_ex(&frame->uc.uc_stack, regs->sp); 362 363 /* Set up to return from userspace. */ 364 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn); 365 if (ksig->ka.sa.sa_flags & SA_RESTORER) 366 restorer = ksig->ka.sa.sa_restorer; 367 put_user_ex(restorer, &frame->pretcode); 368 369 /* 370 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 371 * 372 * WE DO NOT USE IT ANY MORE! It's only left here for historical 373 * reasons and because gdb uses it as a signature to notice 374 * signal handler stack frames. 375 */ 376 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); 377 } put_user_catch(err); 378 379 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 380 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, 381 regs, set->sig[0]); 382 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 383 384 if (err) 385 return -EFAULT; 386 387 /* Set up registers for signal handler */ 388 regs->sp = (unsigned long)frame; 389 regs->ip = (unsigned long)ksig->ka.sa.sa_handler; 390 regs->ax = (unsigned long)sig; 391 regs->dx = (unsigned long)&frame->info; 392 regs->cx = (unsigned long)&frame->uc; 393 394 regs->ds = __USER_DS; 395 regs->es = __USER_DS; 396 regs->ss = __USER_DS; 397 regs->cs = __USER_CS; 398 399 return 0; 400 } 401 #else /* !CONFIG_X86_32 */ 402 static int __setup_rt_frame(int sig, struct ksignal *ksig, 403 sigset_t *set, struct pt_regs *regs) 404 { 405 struct rt_sigframe __user *frame; 406 void __user *fp = NULL; 407 int err = 0; 408 409 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); 410 411 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 412 return -EFAULT; 413 414 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 415 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 416 return -EFAULT; 417 } 418 419 put_user_try { 420 /* Create the ucontext. */ 421 if (cpu_has_xsave) 422 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 423 else 424 put_user_ex(0, &frame->uc.uc_flags); 425 put_user_ex(0, &frame->uc.uc_link); 426 save_altstack_ex(&frame->uc.uc_stack, regs->sp); 427 428 /* Set up to return from userspace. If provided, use a stub 429 already in userspace. */ 430 /* x86-64 should always use SA_RESTORER. */ 431 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 432 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); 433 } else { 434 /* could use a vstub here */ 435 err |= -EFAULT; 436 } 437 } put_user_catch(err); 438 439 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); 440 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 441 442 if (err) 443 return -EFAULT; 444 445 /* Set up registers for signal handler */ 446 regs->di = sig; 447 /* In case the signal handler was declared without prototypes */ 448 regs->ax = 0; 449 450 /* This also works for non SA_SIGINFO handlers because they expect the 451 next argument after the signal number on the stack. */ 452 regs->si = (unsigned long)&frame->info; 453 regs->dx = (unsigned long)&frame->uc; 454 regs->ip = (unsigned long) ksig->ka.sa.sa_handler; 455 456 regs->sp = (unsigned long)frame; 457 458 /* Set up the CS register to run signal handlers in 64-bit mode, 459 even if the handler happens to be interrupting 32-bit code. */ 460 regs->cs = __USER_CS; 461 462 return 0; 463 } 464 #endif /* CONFIG_X86_32 */ 465 466 static int x32_setup_rt_frame(struct ksignal *ksig, 467 compat_sigset_t *set, 468 struct pt_regs *regs) 469 { 470 #ifdef CONFIG_X86_X32_ABI 471 struct rt_sigframe_x32 __user *frame; 472 void __user *restorer; 473 int err = 0; 474 void __user *fpstate = NULL; 475 476 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 477 478 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 479 return -EFAULT; 480 481 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 482 if (copy_siginfo_to_user32(&frame->info, &ksig->info)) 483 return -EFAULT; 484 } 485 486 put_user_try { 487 /* Create the ucontext. */ 488 if (cpu_has_xsave) 489 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 490 else 491 put_user_ex(0, &frame->uc.uc_flags); 492 put_user_ex(0, &frame->uc.uc_link); 493 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); 494 put_user_ex(0, &frame->uc.uc__pad0); 495 496 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 497 restorer = ksig->ka.sa.sa_restorer; 498 } else { 499 /* could use a vstub here */ 500 restorer = NULL; 501 err |= -EFAULT; 502 } 503 put_user_ex(restorer, &frame->pretcode); 504 } put_user_catch(err); 505 506 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, 507 regs, set->sig[0]); 508 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 509 510 if (err) 511 return -EFAULT; 512 513 /* Set up registers for signal handler */ 514 regs->sp = (unsigned long) frame; 515 regs->ip = (unsigned long) ksig->ka.sa.sa_handler; 516 517 /* We use the x32 calling convention here... */ 518 regs->di = ksig->sig; 519 regs->si = (unsigned long) &frame->info; 520 regs->dx = (unsigned long) &frame->uc; 521 522 loadsegment(ds, __USER_DS); 523 loadsegment(es, __USER_DS); 524 525 regs->cs = __USER_CS; 526 regs->ss = __USER_DS; 527 #endif /* CONFIG_X86_X32_ABI */ 528 529 return 0; 530 } 531 532 /* 533 * Do a signal return; undo the signal stack. 534 */ 535 #ifdef CONFIG_X86_32 536 asmlinkage unsigned long sys_sigreturn(void) 537 { 538 struct pt_regs *regs = current_pt_regs(); 539 struct sigframe __user *frame; 540 unsigned long ax; 541 sigset_t set; 542 543 frame = (struct sigframe __user *)(regs->sp - 8); 544 545 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 546 goto badframe; 547 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 548 && __copy_from_user(&set.sig[1], &frame->extramask, 549 sizeof(frame->extramask)))) 550 goto badframe; 551 552 set_current_blocked(&set); 553 554 if (restore_sigcontext(regs, &frame->sc, &ax)) 555 goto badframe; 556 return ax; 557 558 badframe: 559 signal_fault(regs, frame, "sigreturn"); 560 561 return 0; 562 } 563 #endif /* CONFIG_X86_32 */ 564 565 asmlinkage long sys_rt_sigreturn(void) 566 { 567 struct pt_regs *regs = current_pt_regs(); 568 struct rt_sigframe __user *frame; 569 unsigned long ax; 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, &ax)) 581 goto badframe; 582 583 if (restore_altstack(&frame->uc.uc_stack)) 584 goto badframe; 585 586 return ax; 587 588 badframe: 589 signal_fault(regs, frame, "rt_sigreturn"); 590 return 0; 591 } 592 593 /* 594 * OK, we're invoking a handler: 595 */ 596 static int signr_convert(int sig) 597 { 598 #ifdef CONFIG_X86_32 599 struct thread_info *info = current_thread_info(); 600 601 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32) 602 return info->exec_domain->signal_invmap[sig]; 603 #endif /* CONFIG_X86_32 */ 604 return sig; 605 } 606 607 static int 608 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 609 { 610 int usig = signr_convert(ksig->sig); 611 sigset_t *set = sigmask_to_save(); 612 compat_sigset_t *cset = (compat_sigset_t *) set; 613 614 /* Set up the stack frame */ 615 if (is_ia32_frame()) { 616 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 617 return ia32_setup_rt_frame(usig, ksig, cset, regs); 618 else 619 return ia32_setup_frame(usig, ksig, cset, regs); 620 } else if (is_x32_frame()) { 621 return x32_setup_rt_frame(ksig, cset, regs); 622 } else { 623 return __setup_rt_frame(ksig->sig, ksig, set, regs); 624 } 625 } 626 627 static void 628 handle_signal(struct ksignal *ksig, struct pt_regs *regs) 629 { 630 bool failed; 631 /* Are we from a system call? */ 632 if (syscall_get_nr(current, regs) >= 0) { 633 /* If so, check system call restarting.. */ 634 switch (syscall_get_error(current, regs)) { 635 case -ERESTART_RESTARTBLOCK: 636 case -ERESTARTNOHAND: 637 regs->ax = -EINTR; 638 break; 639 640 case -ERESTARTSYS: 641 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 642 regs->ax = -EINTR; 643 break; 644 } 645 /* fallthrough */ 646 case -ERESTARTNOINTR: 647 regs->ax = regs->orig_ax; 648 regs->ip -= 2; 649 break; 650 } 651 } 652 653 /* 654 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF 655 * flag so that register information in the sigcontext is correct. 656 */ 657 if (unlikely(regs->flags & X86_EFLAGS_TF) && 658 likely(test_and_clear_thread_flag(TIF_FORCED_TF))) 659 regs->flags &= ~X86_EFLAGS_TF; 660 661 failed = (setup_rt_frame(ksig, regs) < 0); 662 if (!failed) { 663 /* 664 * Clear the direction flag as per the ABI for function entry. 665 * 666 * Clear RF when entering the signal handler, because 667 * it might disable possible debug exception from the 668 * signal handler. 669 * 670 * Clear TF when entering the signal handler, but 671 * notify any tracer that was single-stepping it. 672 * The tracer may want to single-step inside the 673 * handler too. 674 */ 675 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); 676 } 677 signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP)); 678 } 679 680 #ifdef CONFIG_X86_32 681 #define NR_restart_syscall __NR_restart_syscall 682 #else /* !CONFIG_X86_32 */ 683 #define NR_restart_syscall \ 684 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall 685 #endif /* CONFIG_X86_32 */ 686 687 /* 688 * Note that 'init' is a special process: it doesn't get signals it doesn't 689 * want to handle. Thus you cannot kill init even with a SIGKILL even by 690 * mistake. 691 */ 692 static void do_signal(struct pt_regs *regs) 693 { 694 struct ksignal ksig; 695 696 if (get_signal(&ksig)) { 697 /* Whee! Actually deliver the signal. */ 698 handle_signal(&ksig, regs); 699 return; 700 } 701 702 /* Did we come from a system call? */ 703 if (syscall_get_nr(current, regs) >= 0) { 704 /* Restart the system call - no handlers present */ 705 switch (syscall_get_error(current, regs)) { 706 case -ERESTARTNOHAND: 707 case -ERESTARTSYS: 708 case -ERESTARTNOINTR: 709 regs->ax = regs->orig_ax; 710 regs->ip -= 2; 711 break; 712 713 case -ERESTART_RESTARTBLOCK: 714 regs->ax = NR_restart_syscall; 715 regs->ip -= 2; 716 break; 717 } 718 } 719 720 /* 721 * If there's no signal to deliver, we just put the saved sigmask 722 * back. 723 */ 724 restore_saved_sigmask(); 725 } 726 727 /* 728 * notification of userspace execution resumption 729 * - triggered by the TIF_WORK_MASK flags 730 */ 731 __visible void 732 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) 733 { 734 user_exit(); 735 736 #ifdef CONFIG_X86_MCE 737 /* notify userspace of pending MCEs */ 738 if (thread_info_flags & _TIF_MCE_NOTIFY) 739 mce_notify_process(); 740 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */ 741 742 if (thread_info_flags & _TIF_UPROBE) 743 uprobe_notify_resume(regs); 744 745 /* deal with pending signal delivery */ 746 if (thread_info_flags & _TIF_SIGPENDING) 747 do_signal(regs); 748 749 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 750 clear_thread_flag(TIF_NOTIFY_RESUME); 751 tracehook_notify_resume(regs); 752 } 753 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY) 754 fire_user_return_notifiers(); 755 756 user_enter(); 757 } 758 759 void signal_fault(struct pt_regs *regs, void __user *frame, char *where) 760 { 761 struct task_struct *me = current; 762 763 if (show_unhandled_signals && printk_ratelimit()) { 764 printk("%s" 765 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", 766 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, 767 me->comm, me->pid, where, frame, 768 regs->ip, regs->sp, regs->orig_ax); 769 print_vma_addr(" in ", regs->ip); 770 pr_cont("\n"); 771 } 772 773 force_sig(SIGSEGV, me); 774 } 775 776 #ifdef CONFIG_X86_X32_ABI 777 asmlinkage long sys32_x32_rt_sigreturn(void) 778 { 779 struct pt_regs *regs = current_pt_regs(); 780 struct rt_sigframe_x32 __user *frame; 781 sigset_t set; 782 unsigned long ax; 783 784 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); 785 786 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 787 goto badframe; 788 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 789 goto badframe; 790 791 set_current_blocked(&set); 792 793 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax)) 794 goto badframe; 795 796 if (compat_restore_altstack(&frame->uc.uc_stack)) 797 goto badframe; 798 799 return ax; 800 801 badframe: 802 signal_fault(regs, frame, "x32 rt_sigreturn"); 803 return 0; 804 } 805 #endif 806