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 COPY_SEG_CPL3(cs); 97 COPY_SEG_CPL3(ss); 98 99 get_user_ex(tmpflags, &sc->flags); 100 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); 101 regs->orig_ax = -1; /* disable syscall checks */ 102 103 get_user_ex(buf, &sc->fpstate); 104 } get_user_catch(err); 105 106 err |= fpu__restore_sig(buf, config_enabled(CONFIG_X86_32)); 107 108 force_iret(); 109 110 return err; 111 } 112 113 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, 114 struct pt_regs *regs, unsigned long mask) 115 { 116 int err = 0; 117 118 put_user_try { 119 120 #ifdef CONFIG_X86_32 121 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); 122 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); 123 put_user_ex(regs->es, (unsigned int __user *)&sc->es); 124 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); 125 #endif /* CONFIG_X86_32 */ 126 127 put_user_ex(regs->di, &sc->di); 128 put_user_ex(regs->si, &sc->si); 129 put_user_ex(regs->bp, &sc->bp); 130 put_user_ex(regs->sp, &sc->sp); 131 put_user_ex(regs->bx, &sc->bx); 132 put_user_ex(regs->dx, &sc->dx); 133 put_user_ex(regs->cx, &sc->cx); 134 put_user_ex(regs->ax, &sc->ax); 135 #ifdef CONFIG_X86_64 136 put_user_ex(regs->r8, &sc->r8); 137 put_user_ex(regs->r9, &sc->r9); 138 put_user_ex(regs->r10, &sc->r10); 139 put_user_ex(regs->r11, &sc->r11); 140 put_user_ex(regs->r12, &sc->r12); 141 put_user_ex(regs->r13, &sc->r13); 142 put_user_ex(regs->r14, &sc->r14); 143 put_user_ex(regs->r15, &sc->r15); 144 #endif /* CONFIG_X86_64 */ 145 146 put_user_ex(current->thread.trap_nr, &sc->trapno); 147 put_user_ex(current->thread.error_code, &sc->err); 148 put_user_ex(regs->ip, &sc->ip); 149 #ifdef CONFIG_X86_32 150 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); 151 put_user_ex(regs->flags, &sc->flags); 152 put_user_ex(regs->sp, &sc->sp_at_signal); 153 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); 154 #else /* !CONFIG_X86_32 */ 155 put_user_ex(regs->flags, &sc->flags); 156 put_user_ex(regs->cs, &sc->cs); 157 put_user_ex(0, &sc->__pad2); 158 put_user_ex(0, &sc->__pad1); 159 put_user_ex(regs->ss, &sc->ss); 160 #endif /* CONFIG_X86_32 */ 161 162 put_user_ex(fpstate, &sc->fpstate); 163 164 /* non-iBCS2 extensions.. */ 165 put_user_ex(mask, &sc->oldmask); 166 put_user_ex(current->thread.cr2, &sc->cr2); 167 } put_user_catch(err); 168 169 return err; 170 } 171 172 /* 173 * Set up a signal frame. 174 */ 175 176 /* 177 * Determine which stack to use.. 178 */ 179 static unsigned long align_sigframe(unsigned long sp) 180 { 181 #ifdef CONFIG_X86_32 182 /* 183 * Align the stack pointer according to the i386 ABI, 184 * i.e. so that on function entry ((sp + 4) & 15) == 0. 185 */ 186 sp = ((sp + 4) & -16ul) - 4; 187 #else /* !CONFIG_X86_32 */ 188 sp = round_down(sp, 16) - 8; 189 #endif 190 return sp; 191 } 192 193 static inline void __user * 194 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 195 void __user **fpstate) 196 { 197 /* Default to using normal stack */ 198 unsigned long math_size = 0; 199 unsigned long sp = regs->sp; 200 unsigned long buf_fx = 0; 201 int onsigstack = on_sig_stack(sp); 202 struct fpu *fpu = ¤t->thread.fpu; 203 204 /* redzone */ 205 if (config_enabled(CONFIG_X86_64)) 206 sp -= 128; 207 208 if (!onsigstack) { 209 /* This is the X/Open sanctioned signal stack switching. */ 210 if (ka->sa.sa_flags & SA_ONSTACK) { 211 if (current->sas_ss_size) 212 sp = current->sas_ss_sp + current->sas_ss_size; 213 } else if (config_enabled(CONFIG_X86_32) && 214 (regs->ss & 0xffff) != __USER_DS && 215 !(ka->sa.sa_flags & SA_RESTORER) && 216 ka->sa.sa_restorer) { 217 /* This is the legacy signal stack switching. */ 218 sp = (unsigned long) ka->sa.sa_restorer; 219 } 220 } 221 222 if (fpu->fpstate_active) { 223 sp = fpu__alloc_mathframe(sp, config_enabled(CONFIG_X86_32), 224 &buf_fx, &math_size); 225 *fpstate = (void __user *)sp; 226 } 227 228 sp = align_sigframe(sp - frame_size); 229 230 /* 231 * If we are on the alternate signal stack and would overflow it, don't. 232 * Return an always-bogus address instead so we will die with SIGSEGV. 233 */ 234 if (onsigstack && !likely(on_sig_stack(sp))) 235 return (void __user *)-1L; 236 237 /* save i387 and extended state */ 238 if (fpu->fpstate_active && 239 copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0) 240 return (void __user *)-1L; 241 242 return (void __user *)sp; 243 } 244 245 #ifdef CONFIG_X86_32 246 static const struct { 247 u16 poplmovl; 248 u32 val; 249 u16 int80; 250 } __attribute__((packed)) retcode = { 251 0xb858, /* popl %eax; movl $..., %eax */ 252 __NR_sigreturn, 253 0x80cd, /* int $0x80 */ 254 }; 255 256 static const struct { 257 u8 movl; 258 u32 val; 259 u16 int80; 260 u8 pad; 261 } __attribute__((packed)) rt_retcode = { 262 0xb8, /* movl $..., %eax */ 263 __NR_rt_sigreturn, 264 0x80cd, /* int $0x80 */ 265 0 266 }; 267 268 static int 269 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, 270 struct pt_regs *regs) 271 { 272 struct sigframe __user *frame; 273 void __user *restorer; 274 int err = 0; 275 void __user *fpstate = NULL; 276 277 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 278 279 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 280 return -EFAULT; 281 282 if (__put_user(sig, &frame->sig)) 283 return -EFAULT; 284 285 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) 286 return -EFAULT; 287 288 if (_NSIG_WORDS > 1) { 289 if (__copy_to_user(&frame->extramask, &set->sig[1], 290 sizeof(frame->extramask))) 291 return -EFAULT; 292 } 293 294 if (current->mm->context.vdso) 295 restorer = current->mm->context.vdso + 296 selected_vdso32->sym___kernel_sigreturn; 297 else 298 restorer = &frame->retcode; 299 if (ksig->ka.sa.sa_flags & SA_RESTORER) 300 restorer = ksig->ka.sa.sa_restorer; 301 302 /* Set up to return from userspace. */ 303 err |= __put_user(restorer, &frame->pretcode); 304 305 /* 306 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 307 * 308 * WE DO NOT USE IT ANY MORE! It's only left here for historical 309 * reasons and because gdb uses it as a signature to notice 310 * signal handler stack frames. 311 */ 312 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); 313 314 if (err) 315 return -EFAULT; 316 317 /* Set up registers for signal handler */ 318 regs->sp = (unsigned long)frame; 319 regs->ip = (unsigned long)ksig->ka.sa.sa_handler; 320 regs->ax = (unsigned long)sig; 321 regs->dx = 0; 322 regs->cx = 0; 323 324 regs->ds = __USER_DS; 325 regs->es = __USER_DS; 326 regs->ss = __USER_DS; 327 regs->cs = __USER_CS; 328 329 return 0; 330 } 331 332 static int __setup_rt_frame(int sig, struct ksignal *ksig, 333 sigset_t *set, struct pt_regs *regs) 334 { 335 struct rt_sigframe __user *frame; 336 void __user *restorer; 337 int err = 0; 338 void __user *fpstate = NULL; 339 340 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 341 342 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 343 return -EFAULT; 344 345 put_user_try { 346 put_user_ex(sig, &frame->sig); 347 put_user_ex(&frame->info, &frame->pinfo); 348 put_user_ex(&frame->uc, &frame->puc); 349 350 /* Create the ucontext. */ 351 if (cpu_has_xsave) 352 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 353 else 354 put_user_ex(0, &frame->uc.uc_flags); 355 put_user_ex(0, &frame->uc.uc_link); 356 save_altstack_ex(&frame->uc.uc_stack, regs->sp); 357 358 /* Set up to return from userspace. */ 359 restorer = current->mm->context.vdso + 360 selected_vdso32->sym___kernel_rt_sigreturn; 361 if (ksig->ka.sa.sa_flags & SA_RESTORER) 362 restorer = ksig->ka.sa.sa_restorer; 363 put_user_ex(restorer, &frame->pretcode); 364 365 /* 366 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 367 * 368 * WE DO NOT USE IT ANY MORE! It's only left here for historical 369 * reasons and because gdb uses it as a signature to notice 370 * signal handler stack frames. 371 */ 372 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); 373 } put_user_catch(err); 374 375 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 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 if (err) 381 return -EFAULT; 382 383 /* Set up registers for signal handler */ 384 regs->sp = (unsigned long)frame; 385 regs->ip = (unsigned long)ksig->ka.sa.sa_handler; 386 regs->ax = (unsigned long)sig; 387 regs->dx = (unsigned long)&frame->info; 388 regs->cx = (unsigned long)&frame->uc; 389 390 regs->ds = __USER_DS; 391 regs->es = __USER_DS; 392 regs->ss = __USER_DS; 393 regs->cs = __USER_CS; 394 395 return 0; 396 } 397 #else /* !CONFIG_X86_32 */ 398 static int __setup_rt_frame(int sig, struct ksignal *ksig, 399 sigset_t *set, struct pt_regs *regs) 400 { 401 struct rt_sigframe __user *frame; 402 void __user *fp = NULL; 403 int err = 0; 404 405 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); 406 407 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 408 return -EFAULT; 409 410 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 411 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 412 return -EFAULT; 413 } 414 415 put_user_try { 416 /* Create the ucontext. */ 417 if (cpu_has_xsave) 418 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 419 else 420 put_user_ex(0, &frame->uc.uc_flags); 421 put_user_ex(0, &frame->uc.uc_link); 422 save_altstack_ex(&frame->uc.uc_stack, regs->sp); 423 424 /* Set up to return from userspace. If provided, use a stub 425 already in userspace. */ 426 /* x86-64 should always use SA_RESTORER. */ 427 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 428 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); 429 } else { 430 /* could use a vstub here */ 431 err |= -EFAULT; 432 } 433 } put_user_catch(err); 434 435 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); 436 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 437 438 if (err) 439 return -EFAULT; 440 441 /* Set up registers for signal handler */ 442 regs->di = sig; 443 /* In case the signal handler was declared without prototypes */ 444 regs->ax = 0; 445 446 /* This also works for non SA_SIGINFO handlers because they expect the 447 next argument after the signal number on the stack. */ 448 regs->si = (unsigned long)&frame->info; 449 regs->dx = (unsigned long)&frame->uc; 450 regs->ip = (unsigned long) ksig->ka.sa.sa_handler; 451 452 regs->sp = (unsigned long)frame; 453 454 /* 455 * Set up the CS and SS registers to run signal handlers in 456 * 64-bit mode, even if the handler happens to be interrupting 457 * 32-bit or 16-bit code. 458 * 459 * SS is subtle. In 64-bit mode, we don't need any particular 460 * SS descriptor, but we do need SS to be valid. It's possible 461 * that the old SS is entirely bogus -- this can happen if the 462 * signal we're trying to deliver is #GP or #SS caused by a bad 463 * SS value. 464 */ 465 regs->cs = __USER_CS; 466 regs->ss = __USER_DS; 467 468 return 0; 469 } 470 #endif /* CONFIG_X86_32 */ 471 472 static int x32_setup_rt_frame(struct ksignal *ksig, 473 compat_sigset_t *set, 474 struct pt_regs *regs) 475 { 476 #ifdef CONFIG_X86_X32_ABI 477 struct rt_sigframe_x32 __user *frame; 478 void __user *restorer; 479 int err = 0; 480 void __user *fpstate = NULL; 481 482 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 483 484 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 485 return -EFAULT; 486 487 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 488 if (copy_siginfo_to_user32(&frame->info, &ksig->info)) 489 return -EFAULT; 490 } 491 492 put_user_try { 493 /* Create the ucontext. */ 494 if (cpu_has_xsave) 495 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 496 else 497 put_user_ex(0, &frame->uc.uc_flags); 498 put_user_ex(0, &frame->uc.uc_link); 499 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); 500 put_user_ex(0, &frame->uc.uc__pad0); 501 502 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 503 restorer = ksig->ka.sa.sa_restorer; 504 } else { 505 /* could use a vstub here */ 506 restorer = NULL; 507 err |= -EFAULT; 508 } 509 put_user_ex(restorer, &frame->pretcode); 510 } put_user_catch(err); 511 512 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, 513 regs, set->sig[0]); 514 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 515 516 if (err) 517 return -EFAULT; 518 519 /* Set up registers for signal handler */ 520 regs->sp = (unsigned long) frame; 521 regs->ip = (unsigned long) ksig->ka.sa.sa_handler; 522 523 /* We use the x32 calling convention here... */ 524 regs->di = ksig->sig; 525 regs->si = (unsigned long) &frame->info; 526 regs->dx = (unsigned long) &frame->uc; 527 528 loadsegment(ds, __USER_DS); 529 loadsegment(es, __USER_DS); 530 531 regs->cs = __USER_CS; 532 regs->ss = __USER_DS; 533 #endif /* CONFIG_X86_X32_ABI */ 534 535 return 0; 536 } 537 538 /* 539 * Do a signal return; undo the signal stack. 540 */ 541 #ifdef CONFIG_X86_32 542 asmlinkage unsigned long sys_sigreturn(void) 543 { 544 struct pt_regs *regs = current_pt_regs(); 545 struct sigframe __user *frame; 546 sigset_t set; 547 548 frame = (struct sigframe __user *)(regs->sp - 8); 549 550 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 551 goto badframe; 552 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 553 && __copy_from_user(&set.sig[1], &frame->extramask, 554 sizeof(frame->extramask)))) 555 goto badframe; 556 557 set_current_blocked(&set); 558 559 if (restore_sigcontext(regs, &frame->sc)) 560 goto badframe; 561 return regs->ax; 562 563 badframe: 564 signal_fault(regs, frame, "sigreturn"); 565 566 return 0; 567 } 568 #endif /* CONFIG_X86_32 */ 569 570 asmlinkage long sys_rt_sigreturn(void) 571 { 572 struct pt_regs *regs = current_pt_regs(); 573 struct rt_sigframe __user *frame; 574 sigset_t set; 575 576 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); 577 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 578 goto badframe; 579 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 580 goto badframe; 581 582 set_current_blocked(&set); 583 584 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 585 goto badframe; 586 587 if (restore_altstack(&frame->uc.uc_stack)) 588 goto badframe; 589 590 return regs->ax; 591 592 badframe: 593 signal_fault(regs, frame, "rt_sigreturn"); 594 return 0; 595 } 596 597 static inline int is_ia32_compat_frame(void) 598 { 599 return config_enabled(CONFIG_IA32_EMULATION) && 600 test_thread_flag(TIF_IA32); 601 } 602 603 static inline int is_ia32_frame(void) 604 { 605 return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame(); 606 } 607 608 static inline int is_x32_frame(void) 609 { 610 return config_enabled(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32); 611 } 612 613 static int 614 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 615 { 616 int usig = ksig->sig; 617 sigset_t *set = sigmask_to_save(); 618 compat_sigset_t *cset = (compat_sigset_t *) set; 619 620 /* Set up the stack frame */ 621 if (is_ia32_frame()) { 622 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 623 return ia32_setup_rt_frame(usig, ksig, cset, regs); 624 else 625 return ia32_setup_frame(usig, ksig, cset, regs); 626 } else if (is_x32_frame()) { 627 return x32_setup_rt_frame(ksig, cset, regs); 628 } else { 629 return __setup_rt_frame(ksig->sig, ksig, set, regs); 630 } 631 } 632 633 static void 634 handle_signal(struct ksignal *ksig, struct pt_regs *regs) 635 { 636 bool stepping, failed; 637 struct fpu *fpu = ¤t->thread.fpu; 638 639 /* Are we from a system call? */ 640 if (syscall_get_nr(current, regs) >= 0) { 641 /* If so, check system call restarting.. */ 642 switch (syscall_get_error(current, regs)) { 643 case -ERESTART_RESTARTBLOCK: 644 case -ERESTARTNOHAND: 645 regs->ax = -EINTR; 646 break; 647 648 case -ERESTARTSYS: 649 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 650 regs->ax = -EINTR; 651 break; 652 } 653 /* fallthrough */ 654 case -ERESTARTNOINTR: 655 regs->ax = regs->orig_ax; 656 regs->ip -= 2; 657 break; 658 } 659 } 660 661 /* 662 * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now 663 * so that register information in the sigcontext is correct and 664 * then notify the tracer before entering the signal handler. 665 */ 666 stepping = test_thread_flag(TIF_SINGLESTEP); 667 if (stepping) 668 user_disable_single_step(current); 669 670 failed = (setup_rt_frame(ksig, regs) < 0); 671 if (!failed) { 672 /* 673 * Clear the direction flag as per the ABI for function entry. 674 * 675 * Clear RF when entering the signal handler, because 676 * it might disable possible debug exception from the 677 * signal handler. 678 * 679 * Clear TF for the case when it wasn't set by debugger to 680 * avoid the recursive send_sigtrap() in SIGTRAP handler. 681 */ 682 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); 683 /* 684 * Ensure the signal handler starts with the new fpu state. 685 */ 686 if (fpu->fpstate_active) 687 fpu__clear(fpu); 688 } 689 signal_setup_done(failed, ksig, stepping); 690 } 691 692 #ifdef CONFIG_X86_32 693 #define NR_restart_syscall __NR_restart_syscall 694 #else /* !CONFIG_X86_32 */ 695 #define NR_restart_syscall \ 696 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall 697 #endif /* CONFIG_X86_32 */ 698 699 /* 700 * Note that 'init' is a special process: it doesn't get signals it doesn't 701 * want to handle. Thus you cannot kill init even with a SIGKILL even by 702 * mistake. 703 */ 704 static void do_signal(struct pt_regs *regs) 705 { 706 struct ksignal ksig; 707 708 if (get_signal(&ksig)) { 709 /* Whee! Actually deliver the signal. */ 710 handle_signal(&ksig, regs); 711 return; 712 } 713 714 /* Did we come from a system call? */ 715 if (syscall_get_nr(current, regs) >= 0) { 716 /* Restart the system call - no handlers present */ 717 switch (syscall_get_error(current, regs)) { 718 case -ERESTARTNOHAND: 719 case -ERESTARTSYS: 720 case -ERESTARTNOINTR: 721 regs->ax = regs->orig_ax; 722 regs->ip -= 2; 723 break; 724 725 case -ERESTART_RESTARTBLOCK: 726 regs->ax = NR_restart_syscall; 727 regs->ip -= 2; 728 break; 729 } 730 } 731 732 /* 733 * If there's no signal to deliver, we just put the saved sigmask 734 * back. 735 */ 736 restore_saved_sigmask(); 737 } 738 739 /* 740 * notification of userspace execution resumption 741 * - triggered by the TIF_WORK_MASK flags 742 */ 743 __visible void 744 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) 745 { 746 user_exit(); 747 748 if (thread_info_flags & _TIF_UPROBE) 749 uprobe_notify_resume(regs); 750 751 /* deal with pending signal delivery */ 752 if (thread_info_flags & _TIF_SIGPENDING) 753 do_signal(regs); 754 755 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 756 clear_thread_flag(TIF_NOTIFY_RESUME); 757 tracehook_notify_resume(regs); 758 } 759 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY) 760 fire_user_return_notifiers(); 761 762 user_enter(); 763 } 764 765 void signal_fault(struct pt_regs *regs, void __user *frame, char *where) 766 { 767 struct task_struct *me = current; 768 769 if (show_unhandled_signals && printk_ratelimit()) { 770 printk("%s" 771 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", 772 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, 773 me->comm, me->pid, where, frame, 774 regs->ip, regs->sp, regs->orig_ax); 775 print_vma_addr(" in ", regs->ip); 776 pr_cont("\n"); 777 } 778 779 force_sig(SIGSEGV, me); 780 } 781 782 #ifdef CONFIG_X86_X32_ABI 783 asmlinkage long sys32_x32_rt_sigreturn(void) 784 { 785 struct pt_regs *regs = current_pt_regs(); 786 struct rt_sigframe_x32 __user *frame; 787 sigset_t set; 788 789 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); 790 791 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 792 goto badframe; 793 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 794 goto badframe; 795 796 set_current_blocked(&set); 797 798 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 799 goto badframe; 800 801 if (compat_restore_altstack(&frame->uc.uc_stack)) 802 goto badframe; 803 804 return regs->ax; 805 806 badframe: 807 signal_fault(regs, frame, "x32 rt_sigreturn"); 808 return 0; 809 } 810 #endif 811