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 #include <asm/vm86.h> 35 36 #ifdef CONFIG_X86_64 37 #include <asm/proto.h> 38 #include <asm/ia32_unistd.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 #ifdef CONFIG_X86_64 65 /* 66 * If regs->ss will cause an IRET fault, change it. Otherwise leave it 67 * alone. Using this generally makes no sense unless 68 * user_64bit_mode(regs) would return true. 69 */ 70 static void force_valid_ss(struct pt_regs *regs) 71 { 72 u32 ar; 73 asm volatile ("lar %[old_ss], %[ar]\n\t" 74 "jz 1f\n\t" /* If invalid: */ 75 "xorl %[ar], %[ar]\n\t" /* set ar = 0 */ 76 "1:" 77 : [ar] "=r" (ar) 78 : [old_ss] "rm" ((u16)regs->ss)); 79 80 /* 81 * For a valid 64-bit user context, we need DPL 3, type 82 * read-write data or read-write exp-down data, and S and P 83 * set. We can't use VERW because VERW doesn't check the 84 * P bit. 85 */ 86 ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK; 87 if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) && 88 ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) 89 regs->ss = __USER_DS; 90 } 91 #endif 92 93 static int restore_sigcontext(struct pt_regs *regs, 94 struct sigcontext __user *sc, 95 unsigned long uc_flags) 96 { 97 unsigned long buf_val; 98 void __user *buf; 99 unsigned int tmpflags; 100 unsigned int err = 0; 101 102 /* Always make any pending restarted system calls return -EINTR */ 103 current->restart_block.fn = do_no_restart_syscall; 104 105 get_user_try { 106 107 #ifdef CONFIG_X86_32 108 set_user_gs(regs, GET_SEG(gs)); 109 COPY_SEG(fs); 110 COPY_SEG(es); 111 COPY_SEG(ds); 112 #endif /* CONFIG_X86_32 */ 113 114 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); 115 COPY(dx); COPY(cx); COPY(ip); COPY(ax); 116 117 #ifdef CONFIG_X86_64 118 COPY(r8); 119 COPY(r9); 120 COPY(r10); 121 COPY(r11); 122 COPY(r12); 123 COPY(r13); 124 COPY(r14); 125 COPY(r15); 126 #endif /* CONFIG_X86_64 */ 127 128 COPY_SEG_CPL3(cs); 129 COPY_SEG_CPL3(ss); 130 131 #ifdef CONFIG_X86_64 132 /* 133 * Fix up SS if needed for the benefit of old DOSEMU and 134 * CRIU. 135 */ 136 if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && 137 user_64bit_mode(regs))) 138 force_valid_ss(regs); 139 #endif 140 141 get_user_ex(tmpflags, &sc->flags); 142 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); 143 regs->orig_ax = -1; /* disable syscall checks */ 144 145 get_user_ex(buf_val, &sc->fpstate); 146 buf = (void __user *)buf_val; 147 } get_user_catch(err); 148 149 err |= fpu__restore_sig(buf, config_enabled(CONFIG_X86_32)); 150 151 force_iret(); 152 153 return err; 154 } 155 156 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, 157 struct pt_regs *regs, unsigned long mask) 158 { 159 int err = 0; 160 161 put_user_try { 162 163 #ifdef CONFIG_X86_32 164 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); 165 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); 166 put_user_ex(regs->es, (unsigned int __user *)&sc->es); 167 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); 168 #endif /* CONFIG_X86_32 */ 169 170 put_user_ex(regs->di, &sc->di); 171 put_user_ex(regs->si, &sc->si); 172 put_user_ex(regs->bp, &sc->bp); 173 put_user_ex(regs->sp, &sc->sp); 174 put_user_ex(regs->bx, &sc->bx); 175 put_user_ex(regs->dx, &sc->dx); 176 put_user_ex(regs->cx, &sc->cx); 177 put_user_ex(regs->ax, &sc->ax); 178 #ifdef CONFIG_X86_64 179 put_user_ex(regs->r8, &sc->r8); 180 put_user_ex(regs->r9, &sc->r9); 181 put_user_ex(regs->r10, &sc->r10); 182 put_user_ex(regs->r11, &sc->r11); 183 put_user_ex(regs->r12, &sc->r12); 184 put_user_ex(regs->r13, &sc->r13); 185 put_user_ex(regs->r14, &sc->r14); 186 put_user_ex(regs->r15, &sc->r15); 187 #endif /* CONFIG_X86_64 */ 188 189 put_user_ex(current->thread.trap_nr, &sc->trapno); 190 put_user_ex(current->thread.error_code, &sc->err); 191 put_user_ex(regs->ip, &sc->ip); 192 #ifdef CONFIG_X86_32 193 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); 194 put_user_ex(regs->flags, &sc->flags); 195 put_user_ex(regs->sp, &sc->sp_at_signal); 196 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); 197 #else /* !CONFIG_X86_32 */ 198 put_user_ex(regs->flags, &sc->flags); 199 put_user_ex(regs->cs, &sc->cs); 200 put_user_ex(0, &sc->gs); 201 put_user_ex(0, &sc->fs); 202 put_user_ex(regs->ss, &sc->ss); 203 #endif /* CONFIG_X86_32 */ 204 205 put_user_ex(fpstate, &sc->fpstate); 206 207 /* non-iBCS2 extensions.. */ 208 put_user_ex(mask, &sc->oldmask); 209 put_user_ex(current->thread.cr2, &sc->cr2); 210 } put_user_catch(err); 211 212 return err; 213 } 214 215 /* 216 * Set up a signal frame. 217 */ 218 219 /* 220 * Determine which stack to use.. 221 */ 222 static unsigned long align_sigframe(unsigned long sp) 223 { 224 #ifdef CONFIG_X86_32 225 /* 226 * Align the stack pointer according to the i386 ABI, 227 * i.e. so that on function entry ((sp + 4) & 15) == 0. 228 */ 229 sp = ((sp + 4) & -16ul) - 4; 230 #else /* !CONFIG_X86_32 */ 231 sp = round_down(sp, 16) - 8; 232 #endif 233 return sp; 234 } 235 236 static void __user * 237 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 238 void __user **fpstate) 239 { 240 /* Default to using normal stack */ 241 unsigned long math_size = 0; 242 unsigned long sp = regs->sp; 243 unsigned long buf_fx = 0; 244 int onsigstack = on_sig_stack(sp); 245 struct fpu *fpu = ¤t->thread.fpu; 246 247 /* redzone */ 248 if (config_enabled(CONFIG_X86_64)) 249 sp -= 128; 250 251 /* This is the X/Open sanctioned signal stack switching. */ 252 if (ka->sa.sa_flags & SA_ONSTACK) { 253 if (sas_ss_flags(sp) == 0) 254 sp = current->sas_ss_sp + current->sas_ss_size; 255 } else if (config_enabled(CONFIG_X86_32) && 256 !onsigstack && 257 (regs->ss & 0xffff) != __USER_DS && 258 !(ka->sa.sa_flags & SA_RESTORER) && 259 ka->sa.sa_restorer) { 260 /* This is the legacy signal stack switching. */ 261 sp = (unsigned long) ka->sa.sa_restorer; 262 } 263 264 if (fpu->fpstate_active) { 265 sp = fpu__alloc_mathframe(sp, config_enabled(CONFIG_X86_32), 266 &buf_fx, &math_size); 267 *fpstate = (void __user *)sp; 268 } 269 270 sp = align_sigframe(sp - frame_size); 271 272 /* 273 * If we are on the alternate signal stack and would overflow it, don't. 274 * Return an always-bogus address instead so we will die with SIGSEGV. 275 */ 276 if (onsigstack && !likely(on_sig_stack(sp))) 277 return (void __user *)-1L; 278 279 /* save i387 and extended state */ 280 if (fpu->fpstate_active && 281 copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0) 282 return (void __user *)-1L; 283 284 return (void __user *)sp; 285 } 286 287 #ifdef CONFIG_X86_32 288 static const struct { 289 u16 poplmovl; 290 u32 val; 291 u16 int80; 292 } __attribute__((packed)) retcode = { 293 0xb858, /* popl %eax; movl $..., %eax */ 294 __NR_sigreturn, 295 0x80cd, /* int $0x80 */ 296 }; 297 298 static const struct { 299 u8 movl; 300 u32 val; 301 u16 int80; 302 u8 pad; 303 } __attribute__((packed)) rt_retcode = { 304 0xb8, /* movl $..., %eax */ 305 __NR_rt_sigreturn, 306 0x80cd, /* int $0x80 */ 307 0 308 }; 309 310 static int 311 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, 312 struct pt_regs *regs) 313 { 314 struct sigframe __user *frame; 315 void __user *restorer; 316 int err = 0; 317 void __user *fpstate = NULL; 318 319 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 320 321 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 322 return -EFAULT; 323 324 if (__put_user(sig, &frame->sig)) 325 return -EFAULT; 326 327 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) 328 return -EFAULT; 329 330 if (_NSIG_WORDS > 1) { 331 if (__copy_to_user(&frame->extramask, &set->sig[1], 332 sizeof(frame->extramask))) 333 return -EFAULT; 334 } 335 336 if (current->mm->context.vdso) 337 restorer = current->mm->context.vdso + 338 vdso_image_32.sym___kernel_sigreturn; 339 else 340 restorer = &frame->retcode; 341 if (ksig->ka.sa.sa_flags & SA_RESTORER) 342 restorer = ksig->ka.sa.sa_restorer; 343 344 /* Set up to return from userspace. */ 345 err |= __put_user(restorer, &frame->pretcode); 346 347 /* 348 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 349 * 350 * WE DO NOT USE IT ANY MORE! It's only left here for historical 351 * reasons and because gdb uses it as a signature to notice 352 * signal handler stack frames. 353 */ 354 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); 355 356 if (err) 357 return -EFAULT; 358 359 /* Set up registers for signal handler */ 360 regs->sp = (unsigned long)frame; 361 regs->ip = (unsigned long)ksig->ka.sa.sa_handler; 362 regs->ax = (unsigned long)sig; 363 regs->dx = 0; 364 regs->cx = 0; 365 366 regs->ds = __USER_DS; 367 regs->es = __USER_DS; 368 regs->ss = __USER_DS; 369 regs->cs = __USER_CS; 370 371 return 0; 372 } 373 374 static int __setup_rt_frame(int sig, struct ksignal *ksig, 375 sigset_t *set, struct pt_regs *regs) 376 { 377 struct rt_sigframe __user *frame; 378 void __user *restorer; 379 int err = 0; 380 void __user *fpstate = NULL; 381 382 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 383 384 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 385 return -EFAULT; 386 387 put_user_try { 388 put_user_ex(sig, &frame->sig); 389 put_user_ex(&frame->info, &frame->pinfo); 390 put_user_ex(&frame->uc, &frame->puc); 391 392 /* Create the ucontext. */ 393 if (boot_cpu_has(X86_FEATURE_XSAVE)) 394 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); 395 else 396 put_user_ex(0, &frame->uc.uc_flags); 397 put_user_ex(0, &frame->uc.uc_link); 398 save_altstack_ex(&frame->uc.uc_stack, regs->sp); 399 400 /* Set up to return from userspace. */ 401 restorer = current->mm->context.vdso + 402 vdso_image_32.sym___kernel_rt_sigreturn; 403 if (ksig->ka.sa.sa_flags & SA_RESTORER) 404 restorer = ksig->ka.sa.sa_restorer; 405 put_user_ex(restorer, &frame->pretcode); 406 407 /* 408 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 409 * 410 * WE DO NOT USE IT ANY MORE! It's only left here for historical 411 * reasons and because gdb uses it as a signature to notice 412 * signal handler stack frames. 413 */ 414 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); 415 } put_user_catch(err); 416 417 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 418 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, 419 regs, set->sig[0]); 420 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 421 422 if (err) 423 return -EFAULT; 424 425 /* Set up registers for signal handler */ 426 regs->sp = (unsigned long)frame; 427 regs->ip = (unsigned long)ksig->ka.sa.sa_handler; 428 regs->ax = (unsigned long)sig; 429 regs->dx = (unsigned long)&frame->info; 430 regs->cx = (unsigned long)&frame->uc; 431 432 regs->ds = __USER_DS; 433 regs->es = __USER_DS; 434 regs->ss = __USER_DS; 435 regs->cs = __USER_CS; 436 437 return 0; 438 } 439 #else /* !CONFIG_X86_32 */ 440 static unsigned long frame_uc_flags(struct pt_regs *regs) 441 { 442 unsigned long flags; 443 444 if (boot_cpu_has(X86_FEATURE_XSAVE)) 445 flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; 446 else 447 flags = UC_SIGCONTEXT_SS; 448 449 if (likely(user_64bit_mode(regs))) 450 flags |= UC_STRICT_RESTORE_SS; 451 452 return flags; 453 } 454 455 static int __setup_rt_frame(int sig, struct ksignal *ksig, 456 sigset_t *set, struct pt_regs *regs) 457 { 458 struct rt_sigframe __user *frame; 459 void __user *fp = NULL; 460 int err = 0; 461 462 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); 463 464 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 465 return -EFAULT; 466 467 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 468 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 469 return -EFAULT; 470 } 471 472 put_user_try { 473 /* Create the ucontext. */ 474 put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags); 475 put_user_ex(0, &frame->uc.uc_link); 476 save_altstack_ex(&frame->uc.uc_stack, regs->sp); 477 478 /* Set up to return from userspace. If provided, use a stub 479 already in userspace. */ 480 /* x86-64 should always use SA_RESTORER. */ 481 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 482 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); 483 } else { 484 /* could use a vstub here */ 485 err |= -EFAULT; 486 } 487 } put_user_catch(err); 488 489 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); 490 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 491 492 if (err) 493 return -EFAULT; 494 495 /* Set up registers for signal handler */ 496 regs->di = sig; 497 /* In case the signal handler was declared without prototypes */ 498 regs->ax = 0; 499 500 /* This also works for non SA_SIGINFO handlers because they expect the 501 next argument after the signal number on the stack. */ 502 regs->si = (unsigned long)&frame->info; 503 regs->dx = (unsigned long)&frame->uc; 504 regs->ip = (unsigned long) ksig->ka.sa.sa_handler; 505 506 regs->sp = (unsigned long)frame; 507 508 /* 509 * Set up the CS and SS registers to run signal handlers in 510 * 64-bit mode, even if the handler happens to be interrupting 511 * 32-bit or 16-bit code. 512 * 513 * SS is subtle. In 64-bit mode, we don't need any particular 514 * SS descriptor, but we do need SS to be valid. It's possible 515 * that the old SS is entirely bogus -- this can happen if the 516 * signal we're trying to deliver is #GP or #SS caused by a bad 517 * SS value. We also have a compatbility issue here: DOSEMU 518 * relies on the contents of the SS register indicating the 519 * SS value at the time of the signal, even though that code in 520 * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU 521 * avoids relying on sigreturn to restore SS; instead it uses 522 * a trampoline.) So we do our best: if the old SS was valid, 523 * we keep it. Otherwise we replace it. 524 */ 525 regs->cs = __USER_CS; 526 527 if (unlikely(regs->ss != __USER_DS)) 528 force_valid_ss(regs); 529 530 return 0; 531 } 532 #endif /* CONFIG_X86_32 */ 533 534 static int x32_setup_rt_frame(struct ksignal *ksig, 535 compat_sigset_t *set, 536 struct pt_regs *regs) 537 { 538 #ifdef CONFIG_X86_X32_ABI 539 struct rt_sigframe_x32 __user *frame; 540 void __user *restorer; 541 int err = 0; 542 void __user *fpstate = NULL; 543 544 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); 545 546 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 547 return -EFAULT; 548 549 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 550 if (copy_siginfo_to_user32(&frame->info, &ksig->info)) 551 return -EFAULT; 552 } 553 554 put_user_try { 555 /* Create the ucontext. */ 556 put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags); 557 put_user_ex(0, &frame->uc.uc_link); 558 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); 559 put_user_ex(0, &frame->uc.uc__pad0); 560 561 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 562 restorer = ksig->ka.sa.sa_restorer; 563 } else { 564 /* could use a vstub here */ 565 restorer = NULL; 566 err |= -EFAULT; 567 } 568 put_user_ex(restorer, &frame->pretcode); 569 } put_user_catch(err); 570 571 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, 572 regs, set->sig[0]); 573 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 574 575 if (err) 576 return -EFAULT; 577 578 /* Set up registers for signal handler */ 579 regs->sp = (unsigned long) frame; 580 regs->ip = (unsigned long) ksig->ka.sa.sa_handler; 581 582 /* We use the x32 calling convention here... */ 583 regs->di = ksig->sig; 584 regs->si = (unsigned long) &frame->info; 585 regs->dx = (unsigned long) &frame->uc; 586 587 loadsegment(ds, __USER_DS); 588 loadsegment(es, __USER_DS); 589 590 regs->cs = __USER_CS; 591 regs->ss = __USER_DS; 592 #endif /* CONFIG_X86_X32_ABI */ 593 594 return 0; 595 } 596 597 /* 598 * Do a signal return; undo the signal stack. 599 */ 600 #ifdef CONFIG_X86_32 601 asmlinkage unsigned long sys_sigreturn(void) 602 { 603 struct pt_regs *regs = current_pt_regs(); 604 struct sigframe __user *frame; 605 sigset_t set; 606 607 frame = (struct sigframe __user *)(regs->sp - 8); 608 609 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 610 goto badframe; 611 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 612 && __copy_from_user(&set.sig[1], &frame->extramask, 613 sizeof(frame->extramask)))) 614 goto badframe; 615 616 set_current_blocked(&set); 617 618 /* 619 * x86_32 has no uc_flags bits relevant to restore_sigcontext. 620 * Save a few cycles by skipping the __get_user. 621 */ 622 if (restore_sigcontext(regs, &frame->sc, 0)) 623 goto badframe; 624 return regs->ax; 625 626 badframe: 627 signal_fault(regs, frame, "sigreturn"); 628 629 return 0; 630 } 631 #endif /* CONFIG_X86_32 */ 632 633 asmlinkage long sys_rt_sigreturn(void) 634 { 635 struct pt_regs *regs = current_pt_regs(); 636 struct rt_sigframe __user *frame; 637 sigset_t set; 638 unsigned long uc_flags; 639 640 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); 641 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 642 goto badframe; 643 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 644 goto badframe; 645 if (__get_user(uc_flags, &frame->uc.uc_flags)) 646 goto badframe; 647 648 set_current_blocked(&set); 649 650 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) 651 goto badframe; 652 653 if (restore_altstack(&frame->uc.uc_stack)) 654 goto badframe; 655 656 return regs->ax; 657 658 badframe: 659 signal_fault(regs, frame, "rt_sigreturn"); 660 return 0; 661 } 662 663 static inline int is_ia32_compat_frame(void) 664 { 665 return config_enabled(CONFIG_IA32_EMULATION) && 666 test_thread_flag(TIF_IA32); 667 } 668 669 static inline int is_ia32_frame(void) 670 { 671 return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame(); 672 } 673 674 static inline int is_x32_frame(void) 675 { 676 return config_enabled(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32); 677 } 678 679 static int 680 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 681 { 682 int usig = ksig->sig; 683 sigset_t *set = sigmask_to_save(); 684 compat_sigset_t *cset = (compat_sigset_t *) set; 685 686 /* Set up the stack frame */ 687 if (is_ia32_frame()) { 688 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 689 return ia32_setup_rt_frame(usig, ksig, cset, regs); 690 else 691 return ia32_setup_frame(usig, ksig, cset, regs); 692 } else if (is_x32_frame()) { 693 return x32_setup_rt_frame(ksig, cset, regs); 694 } else { 695 return __setup_rt_frame(ksig->sig, ksig, set, regs); 696 } 697 } 698 699 static void 700 handle_signal(struct ksignal *ksig, struct pt_regs *regs) 701 { 702 bool stepping, failed; 703 struct fpu *fpu = ¤t->thread.fpu; 704 705 if (v8086_mode(regs)) 706 save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); 707 708 /* Are we from a system call? */ 709 if (syscall_get_nr(current, regs) >= 0) { 710 /* If so, check system call restarting.. */ 711 switch (syscall_get_error(current, regs)) { 712 case -ERESTART_RESTARTBLOCK: 713 case -ERESTARTNOHAND: 714 regs->ax = -EINTR; 715 break; 716 717 case -ERESTARTSYS: 718 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 719 regs->ax = -EINTR; 720 break; 721 } 722 /* fallthrough */ 723 case -ERESTARTNOINTR: 724 regs->ax = regs->orig_ax; 725 regs->ip -= 2; 726 break; 727 } 728 } 729 730 /* 731 * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now 732 * so that register information in the sigcontext is correct and 733 * then notify the tracer before entering the signal handler. 734 */ 735 stepping = test_thread_flag(TIF_SINGLESTEP); 736 if (stepping) 737 user_disable_single_step(current); 738 739 failed = (setup_rt_frame(ksig, regs) < 0); 740 if (!failed) { 741 /* 742 * Clear the direction flag as per the ABI for function entry. 743 * 744 * Clear RF when entering the signal handler, because 745 * it might disable possible debug exception from the 746 * signal handler. 747 * 748 * Clear TF for the case when it wasn't set by debugger to 749 * avoid the recursive send_sigtrap() in SIGTRAP handler. 750 */ 751 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); 752 /* 753 * Ensure the signal handler starts with the new fpu state. 754 */ 755 if (fpu->fpstate_active) 756 fpu__clear(fpu); 757 } 758 signal_setup_done(failed, ksig, stepping); 759 } 760 761 static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) 762 { 763 #ifdef CONFIG_X86_64 764 if (in_ia32_syscall()) 765 return __NR_ia32_restart_syscall; 766 #endif 767 #ifdef CONFIG_X86_X32_ABI 768 return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); 769 #else 770 return __NR_restart_syscall; 771 #endif 772 } 773 774 /* 775 * Note that 'init' is a special process: it doesn't get signals it doesn't 776 * want to handle. Thus you cannot kill init even with a SIGKILL even by 777 * mistake. 778 */ 779 void do_signal(struct pt_regs *regs) 780 { 781 struct ksignal ksig; 782 783 if (get_signal(&ksig)) { 784 /* Whee! Actually deliver the signal. */ 785 handle_signal(&ksig, regs); 786 return; 787 } 788 789 /* Did we come from a system call? */ 790 if (syscall_get_nr(current, regs) >= 0) { 791 /* Restart the system call - no handlers present */ 792 switch (syscall_get_error(current, regs)) { 793 case -ERESTARTNOHAND: 794 case -ERESTARTSYS: 795 case -ERESTARTNOINTR: 796 regs->ax = regs->orig_ax; 797 regs->ip -= 2; 798 break; 799 800 case -ERESTART_RESTARTBLOCK: 801 regs->ax = get_nr_restart_syscall(regs); 802 regs->ip -= 2; 803 break; 804 } 805 } 806 807 /* 808 * If there's no signal to deliver, we just put the saved sigmask 809 * back. 810 */ 811 restore_saved_sigmask(); 812 } 813 814 void signal_fault(struct pt_regs *regs, void __user *frame, char *where) 815 { 816 struct task_struct *me = current; 817 818 if (show_unhandled_signals && printk_ratelimit()) { 819 printk("%s" 820 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", 821 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, 822 me->comm, me->pid, where, frame, 823 regs->ip, regs->sp, regs->orig_ax); 824 print_vma_addr(" in ", regs->ip); 825 pr_cont("\n"); 826 } 827 828 force_sig(SIGSEGV, me); 829 } 830 831 #ifdef CONFIG_X86_X32_ABI 832 asmlinkage long sys32_x32_rt_sigreturn(void) 833 { 834 struct pt_regs *regs = current_pt_regs(); 835 struct rt_sigframe_x32 __user *frame; 836 sigset_t set; 837 unsigned long uc_flags; 838 839 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); 840 841 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 842 goto badframe; 843 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 844 goto badframe; 845 if (__get_user(uc_flags, &frame->uc.uc_flags)) 846 goto badframe; 847 848 set_current_blocked(&set); 849 850 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) 851 goto badframe; 852 853 if (compat_restore_altstack(&frame->uc.uc_stack)) 854 goto badframe; 855 856 return regs->ax; 857 858 badframe: 859 signal_fault(regs, frame, "x32 rt_sigreturn"); 860 return 0; 861 } 862 #endif 863