1/* 2 * Copyright (C) 1991, 1992 Linus Torvalds 3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs 4 * 5 * Pentium III FXSR, SSE support 6 * Gareth Hughes <gareth@valinux.com>, May 2000 7 */ 8 9/* 10 * Handle hardware traps and faults. 11 */ 12 13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15#include <linux/context_tracking.h> 16#include <linux/interrupt.h> 17#include <linux/kallsyms.h> 18#include <linux/spinlock.h> 19#include <linux/kprobes.h> 20#include <linux/uaccess.h> 21#include <linux/kdebug.h> 22#include <linux/kgdb.h> 23#include <linux/kernel.h> 24#include <linux/module.h> 25#include <linux/ptrace.h> 26#include <linux/uprobes.h> 27#include <linux/string.h> 28#include <linux/delay.h> 29#include <linux/errno.h> 30#include <linux/kexec.h> 31#include <linux/sched.h> 32#include <linux/timer.h> 33#include <linux/init.h> 34#include <linux/bug.h> 35#include <linux/nmi.h> 36#include <linux/mm.h> 37#include <linux/smp.h> 38#include <linux/io.h> 39 40#ifdef CONFIG_EISA 41#include <linux/ioport.h> 42#include <linux/eisa.h> 43#endif 44 45#if defined(CONFIG_EDAC) 46#include <linux/edac.h> 47#endif 48 49#include <asm/kmemcheck.h> 50#include <asm/stacktrace.h> 51#include <asm/processor.h> 52#include <asm/debugreg.h> 53#include <linux/atomic.h> 54#include <asm/ftrace.h> 55#include <asm/traps.h> 56#include <asm/desc.h> 57#include <asm/i387.h> 58#include <asm/fpu-internal.h> 59#include <asm/mce.h> 60#include <asm/fixmap.h> 61#include <asm/mach_traps.h> 62#include <asm/alternative.h> 63 64#ifdef CONFIG_X86_64 65#include <asm/x86_init.h> 66#include <asm/pgalloc.h> 67#include <asm/proto.h> 68 69/* No need to be aligned, but done to keep all IDTs defined the same way. */ 70gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss; 71#else 72#include <asm/processor-flags.h> 73#include <asm/setup.h> 74 75asmlinkage int system_call(void); 76#endif 77 78/* Must be page-aligned because the real IDT is used in a fixmap. */ 79gate_desc idt_table[NR_VECTORS] __page_aligned_bss; 80 81DECLARE_BITMAP(used_vectors, NR_VECTORS); 82EXPORT_SYMBOL_GPL(used_vectors); 83 84static inline void conditional_sti(struct pt_regs *regs) 85{ 86 if (regs->flags & X86_EFLAGS_IF) 87 local_irq_enable(); 88} 89 90static inline void preempt_conditional_sti(struct pt_regs *regs) 91{ 92 preempt_count_inc(); 93 if (regs->flags & X86_EFLAGS_IF) 94 local_irq_enable(); 95} 96 97static inline void conditional_cli(struct pt_regs *regs) 98{ 99 if (regs->flags & X86_EFLAGS_IF) 100 local_irq_disable(); 101} 102 103static inline void preempt_conditional_cli(struct pt_regs *regs) 104{ 105 if (regs->flags & X86_EFLAGS_IF) 106 local_irq_disable(); 107 preempt_count_dec(); 108} 109 110static nokprobe_inline int 111do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str, 112 struct pt_regs *regs, long error_code) 113{ 114#ifdef CONFIG_X86_32 115 if (regs->flags & X86_VM_MASK) { 116 /* 117 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86. 118 * On nmi (interrupt 2), do_trap should not be called. 119 */ 120 if (trapnr < X86_TRAP_UD) { 121 if (!handle_vm86_trap((struct kernel_vm86_regs *) regs, 122 error_code, trapnr)) 123 return 0; 124 } 125 return -1; 126 } 127#endif 128 if (!user_mode(regs)) { 129 if (!fixup_exception(regs)) { 130 tsk->thread.error_code = error_code; 131 tsk->thread.trap_nr = trapnr; 132 die(str, regs, error_code); 133 } 134 return 0; 135 } 136 137 return -1; 138} 139 140static siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr, 141 siginfo_t *info) 142{ 143 unsigned long siaddr; 144 int sicode; 145 146 switch (trapnr) { 147 default: 148 return SEND_SIG_PRIV; 149 150 case X86_TRAP_DE: 151 sicode = FPE_INTDIV; 152 siaddr = uprobe_get_trap_addr(regs); 153 break; 154 case X86_TRAP_UD: 155 sicode = ILL_ILLOPN; 156 siaddr = uprobe_get_trap_addr(regs); 157 break; 158 case X86_TRAP_AC: 159 sicode = BUS_ADRALN; 160 siaddr = 0; 161 break; 162 } 163 164 info->si_signo = signr; 165 info->si_errno = 0; 166 info->si_code = sicode; 167 info->si_addr = (void __user *)siaddr; 168 return info; 169} 170 171static void 172do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, 173 long error_code, siginfo_t *info) 174{ 175 struct task_struct *tsk = current; 176 177 178 if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code)) 179 return; 180 /* 181 * We want error_code and trap_nr set for userspace faults and 182 * kernelspace faults which result in die(), but not 183 * kernelspace faults which are fixed up. die() gives the 184 * process no chance to handle the signal and notice the 185 * kernel fault information, so that won't result in polluting 186 * the information about previously queued, but not yet 187 * delivered, faults. See also do_general_protection below. 188 */ 189 tsk->thread.error_code = error_code; 190 tsk->thread.trap_nr = trapnr; 191 192#ifdef CONFIG_X86_64 193 if (show_unhandled_signals && unhandled_signal(tsk, signr) && 194 printk_ratelimit()) { 195 pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx", 196 tsk->comm, tsk->pid, str, 197 regs->ip, regs->sp, error_code); 198 print_vma_addr(" in ", regs->ip); 199 pr_cont("\n"); 200 } 201#endif 202 203 force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk); 204} 205NOKPROBE_SYMBOL(do_trap); 206 207static void do_error_trap(struct pt_regs *regs, long error_code, char *str, 208 unsigned long trapnr, int signr) 209{ 210 enum ctx_state prev_state = exception_enter(); 211 siginfo_t info; 212 213 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) != 214 NOTIFY_STOP) { 215 conditional_sti(regs); 216 do_trap(trapnr, signr, str, regs, error_code, 217 fill_trap_info(regs, signr, trapnr, &info)); 218 } 219 220 exception_exit(prev_state); 221} 222 223#define DO_ERROR(trapnr, signr, str, name) \ 224dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ 225{ \ 226 do_error_trap(regs, error_code, str, trapnr, signr); \ 227} 228 229DO_ERROR(X86_TRAP_DE, SIGFPE, "divide error", divide_error) 230DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow) 231DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds) 232DO_ERROR(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op) 233DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",coprocessor_segment_overrun) 234DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS) 235DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present) 236DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment) 237DO_ERROR(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check) 238 239#ifdef CONFIG_X86_64 240/* Runs on IST stack */ 241dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) 242{ 243 static const char str[] = "double fault"; 244 struct task_struct *tsk = current; 245 246#ifdef CONFIG_X86_ESPFIX64 247 extern unsigned char native_irq_return_iret[]; 248 249 /* 250 * If IRET takes a non-IST fault on the espfix64 stack, then we 251 * end up promoting it to a doublefault. In that case, modify 252 * the stack to make it look like we just entered the #GP 253 * handler from user space, similar to bad_iret. 254 */ 255 if (((long)regs->sp >> PGDIR_SHIFT) == ESPFIX_PGD_ENTRY && 256 regs->cs == __KERNEL_CS && 257 regs->ip == (unsigned long)native_irq_return_iret) 258 { 259 struct pt_regs *normal_regs = task_pt_regs(current); 260 261 /* Fake a #GP(0) from userspace. */ 262 memmove(&normal_regs->ip, (void *)regs->sp, 5*8); 263 normal_regs->orig_ax = 0; /* Missing (lost) #GP error code */ 264 regs->ip = (unsigned long)general_protection; 265 regs->sp = (unsigned long)&normal_regs->orig_ax; 266 return; 267 } 268#endif 269 270 exception_enter(); 271 /* Return not checked because double check cannot be ignored */ 272 notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV); 273 274 tsk->thread.error_code = error_code; 275 tsk->thread.trap_nr = X86_TRAP_DF; 276 277#ifdef CONFIG_DOUBLEFAULT 278 df_debug(regs, error_code); 279#endif 280 /* 281 * This is always a kernel trap and never fixable (and thus must 282 * never return). 283 */ 284 for (;;) 285 die(str, regs, error_code); 286} 287#endif 288 289dotraplinkage void 290do_general_protection(struct pt_regs *regs, long error_code) 291{ 292 struct task_struct *tsk; 293 enum ctx_state prev_state; 294 295 prev_state = exception_enter(); 296 conditional_sti(regs); 297 298#ifdef CONFIG_X86_32 299 if (regs->flags & X86_VM_MASK) { 300 local_irq_enable(); 301 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code); 302 goto exit; 303 } 304#endif 305 306 tsk = current; 307 if (!user_mode(regs)) { 308 if (fixup_exception(regs)) 309 goto exit; 310 311 tsk->thread.error_code = error_code; 312 tsk->thread.trap_nr = X86_TRAP_GP; 313 if (notify_die(DIE_GPF, "general protection fault", regs, error_code, 314 X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP) 315 die("general protection fault", regs, error_code); 316 goto exit; 317 } 318 319 tsk->thread.error_code = error_code; 320 tsk->thread.trap_nr = X86_TRAP_GP; 321 322 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && 323 printk_ratelimit()) { 324 pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx", 325 tsk->comm, task_pid_nr(tsk), 326 regs->ip, regs->sp, error_code); 327 print_vma_addr(" in ", regs->ip); 328 pr_cont("\n"); 329 } 330 331 force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk); 332exit: 333 exception_exit(prev_state); 334} 335NOKPROBE_SYMBOL(do_general_protection); 336 337/* May run on IST stack. */ 338dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) 339{ 340 enum ctx_state prev_state; 341 342#ifdef CONFIG_DYNAMIC_FTRACE 343 /* 344 * ftrace must be first, everything else may cause a recursive crash. 345 * See note by declaration of modifying_ftrace_code in ftrace.c 346 */ 347 if (unlikely(atomic_read(&modifying_ftrace_code)) && 348 ftrace_int3_handler(regs)) 349 return; 350#endif 351 if (poke_int3_handler(regs)) 352 return; 353 354 prev_state = exception_enter(); 355#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP 356 if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, 357 SIGTRAP) == NOTIFY_STOP) 358 goto exit; 359#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */ 360 361#ifdef CONFIG_KPROBES 362 if (kprobe_int3_handler(regs)) 363 goto exit; 364#endif 365 366 if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, 367 SIGTRAP) == NOTIFY_STOP) 368 goto exit; 369 370 /* 371 * Let others (NMI) know that the debug stack is in use 372 * as we may switch to the interrupt stack. 373 */ 374 debug_stack_usage_inc(); 375 preempt_conditional_sti(regs); 376 do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL); 377 preempt_conditional_cli(regs); 378 debug_stack_usage_dec(); 379exit: 380 exception_exit(prev_state); 381} 382NOKPROBE_SYMBOL(do_int3); 383 384#ifdef CONFIG_X86_64 385/* 386 * Help handler running on IST stack to switch back to user stack 387 * for scheduling or signal handling. The actual stack switch is done in 388 * entry.S 389 */ 390asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs) 391{ 392 struct pt_regs *regs = eregs; 393 /* Did already sync */ 394 if (eregs == (struct pt_regs *)eregs->sp) 395 ; 396 /* Exception from user space */ 397 else if (user_mode(eregs)) 398 regs = task_pt_regs(current); 399 /* 400 * Exception from kernel and interrupts are enabled. Move to 401 * kernel process stack. 402 */ 403 else if (eregs->flags & X86_EFLAGS_IF) 404 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs)); 405 if (eregs != regs) 406 *regs = *eregs; 407 return regs; 408} 409NOKPROBE_SYMBOL(sync_regs); 410 411struct bad_iret_stack { 412 void *error_entry_ret; 413 struct pt_regs regs; 414}; 415 416asmlinkage __visible notrace 417struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) 418{ 419 /* 420 * This is called from entry_64.S early in handling a fault 421 * caused by a bad iret to user mode. To handle the fault 422 * correctly, we want move our stack frame to task_pt_regs 423 * and we want to pretend that the exception came from the 424 * iret target. 425 */ 426 struct bad_iret_stack *new_stack = 427 container_of(task_pt_regs(current), 428 struct bad_iret_stack, regs); 429 430 /* Copy the IRET target to the new stack. */ 431 memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8); 432 433 /* Copy the remainder of the stack from the current stack. */ 434 memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip)); 435 436 BUG_ON(!user_mode_vm(&new_stack->regs)); 437 return new_stack; 438} 439NOKPROBE_SYMBOL(fixup_bad_iret); 440#endif 441 442/* 443 * Our handling of the processor debug registers is non-trivial. 444 * We do not clear them on entry and exit from the kernel. Therefore 445 * it is possible to get a watchpoint trap here from inside the kernel. 446 * However, the code in ./ptrace.c has ensured that the user can 447 * only set watchpoints on userspace addresses. Therefore the in-kernel 448 * watchpoint trap can only occur in code which is reading/writing 449 * from user space. Such code must not hold kernel locks (since it 450 * can equally take a page fault), therefore it is safe to call 451 * force_sig_info even though that claims and releases locks. 452 * 453 * Code in ./signal.c ensures that the debug control register 454 * is restored before we deliver any signal, and therefore that 455 * user code runs with the correct debug control register even though 456 * we clear it here. 457 * 458 * Being careful here means that we don't have to be as careful in a 459 * lot of more complicated places (task switching can be a bit lazy 460 * about restoring all the debug state, and ptrace doesn't have to 461 * find every occurrence of the TF bit that could be saved away even 462 * by user code) 463 * 464 * May run on IST stack. 465 */ 466dotraplinkage void do_debug(struct pt_regs *regs, long error_code) 467{ 468 struct task_struct *tsk = current; 469 enum ctx_state prev_state; 470 int user_icebp = 0; 471 unsigned long dr6; 472 int si_code; 473 474 prev_state = exception_enter(); 475 476 get_debugreg(dr6, 6); 477 478 /* Filter out all the reserved bits which are preset to 1 */ 479 dr6 &= ~DR6_RESERVED; 480 481 /* 482 * If dr6 has no reason to give us about the origin of this trap, 483 * then it's very likely the result of an icebp/int01 trap. 484 * User wants a sigtrap for that. 485 */ 486 if (!dr6 && user_mode(regs)) 487 user_icebp = 1; 488 489 /* Catch kmemcheck conditions first of all! */ 490 if ((dr6 & DR_STEP) && kmemcheck_trap(regs)) 491 goto exit; 492 493 /* DR6 may or may not be cleared by the CPU */ 494 set_debugreg(0, 6); 495 496 /* 497 * The processor cleared BTF, so don't mark that we need it set. 498 */ 499 clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP); 500 501 /* Store the virtualized DR6 value */ 502 tsk->thread.debugreg6 = dr6; 503 504#ifdef CONFIG_KPROBES 505 if (kprobe_debug_handler(regs)) 506 goto exit; 507#endif 508 509 if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code, 510 SIGTRAP) == NOTIFY_STOP) 511 goto exit; 512 513 /* 514 * Let others (NMI) know that the debug stack is in use 515 * as we may switch to the interrupt stack. 516 */ 517 debug_stack_usage_inc(); 518 519 /* It's safe to allow irq's after DR6 has been saved */ 520 preempt_conditional_sti(regs); 521 522 if (regs->flags & X86_VM_MASK) { 523 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 524 X86_TRAP_DB); 525 preempt_conditional_cli(regs); 526 debug_stack_usage_dec(); 527 goto exit; 528 } 529 530 /* 531 * Single-stepping through system calls: ignore any exceptions in 532 * kernel space, but re-enable TF when returning to user mode. 533 * 534 * We already checked v86 mode above, so we can check for kernel mode 535 * by just checking the CPL of CS. 536 */ 537 if ((dr6 & DR_STEP) && !user_mode(regs)) { 538 tsk->thread.debugreg6 &= ~DR_STEP; 539 set_tsk_thread_flag(tsk, TIF_SINGLESTEP); 540 regs->flags &= ~X86_EFLAGS_TF; 541 } 542 si_code = get_si_code(tsk->thread.debugreg6); 543 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp) 544 send_sigtrap(tsk, regs, error_code, si_code); 545 preempt_conditional_cli(regs); 546 debug_stack_usage_dec(); 547 548exit: 549 exception_exit(prev_state); 550} 551NOKPROBE_SYMBOL(do_debug); 552 553/* 554 * Note that we play around with the 'TS' bit in an attempt to get 555 * the correct behaviour even in the presence of the asynchronous 556 * IRQ13 behaviour 557 */ 558static void math_error(struct pt_regs *regs, int error_code, int trapnr) 559{ 560 struct task_struct *task = current; 561 siginfo_t info; 562 unsigned short err; 563 char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" : 564 "simd exception"; 565 566 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP) 567 return; 568 conditional_sti(regs); 569 570 if (!user_mode_vm(regs)) 571 { 572 if (!fixup_exception(regs)) { 573 task->thread.error_code = error_code; 574 task->thread.trap_nr = trapnr; 575 die(str, regs, error_code); 576 } 577 return; 578 } 579 580 /* 581 * Save the info for the exception handler and clear the error. 582 */ 583 save_init_fpu(task); 584 task->thread.trap_nr = trapnr; 585 task->thread.error_code = error_code; 586 info.si_signo = SIGFPE; 587 info.si_errno = 0; 588 info.si_addr = (void __user *)uprobe_get_trap_addr(regs); 589 if (trapnr == X86_TRAP_MF) { 590 unsigned short cwd, swd; 591 /* 592 * (~cwd & swd) will mask out exceptions that are not set to unmasked 593 * status. 0x3f is the exception bits in these regs, 0x200 is the 594 * C1 reg you need in case of a stack fault, 0x040 is the stack 595 * fault bit. We should only be taking one exception at a time, 596 * so if this combination doesn't produce any single exception, 597 * then we have a bad program that isn't synchronizing its FPU usage 598 * and it will suffer the consequences since we won't be able to 599 * fully reproduce the context of the exception 600 */ 601 cwd = get_fpu_cwd(task); 602 swd = get_fpu_swd(task); 603 604 err = swd & ~cwd; 605 } else { 606 /* 607 * The SIMD FPU exceptions are handled a little differently, as there 608 * is only a single status/control register. Thus, to determine which 609 * unmasked exception was caught we must mask the exception mask bits 610 * at 0x1f80, and then use these to mask the exception bits at 0x3f. 611 */ 612 unsigned short mxcsr = get_fpu_mxcsr(task); 613 err = ~(mxcsr >> 7) & mxcsr; 614 } 615 616 if (err & 0x001) { /* Invalid op */ 617 /* 618 * swd & 0x240 == 0x040: Stack Underflow 619 * swd & 0x240 == 0x240: Stack Overflow 620 * User must clear the SF bit (0x40) if set 621 */ 622 info.si_code = FPE_FLTINV; 623 } else if (err & 0x004) { /* Divide by Zero */ 624 info.si_code = FPE_FLTDIV; 625 } else if (err & 0x008) { /* Overflow */ 626 info.si_code = FPE_FLTOVF; 627 } else if (err & 0x012) { /* Denormal, Underflow */ 628 info.si_code = FPE_FLTUND; 629 } else if (err & 0x020) { /* Precision */ 630 info.si_code = FPE_FLTRES; 631 } else { 632 /* 633 * If we're using IRQ 13, or supposedly even some trap 634 * X86_TRAP_MF implementations, it's possible 635 * we get a spurious trap, which is not an error. 636 */ 637 return; 638 } 639 force_sig_info(SIGFPE, &info, task); 640} 641 642dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) 643{ 644 enum ctx_state prev_state; 645 646 prev_state = exception_enter(); 647 math_error(regs, error_code, X86_TRAP_MF); 648 exception_exit(prev_state); 649} 650 651dotraplinkage void 652do_simd_coprocessor_error(struct pt_regs *regs, long error_code) 653{ 654 enum ctx_state prev_state; 655 656 prev_state = exception_enter(); 657 math_error(regs, error_code, X86_TRAP_XF); 658 exception_exit(prev_state); 659} 660 661dotraplinkage void 662do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) 663{ 664 conditional_sti(regs); 665#if 0 666 /* No need to warn about this any longer. */ 667 pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n"); 668#endif 669} 670 671asmlinkage __visible void __attribute__((weak)) smp_thermal_interrupt(void) 672{ 673} 674 675asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void) 676{ 677} 678 679/* 680 * 'math_state_restore()' saves the current math information in the 681 * old math state array, and gets the new ones from the current task 682 * 683 * Careful.. There are problems with IBM-designed IRQ13 behaviour. 684 * Don't touch unless you *really* know how it works. 685 * 686 * Must be called with kernel preemption disabled (eg with local 687 * local interrupts as in the case of do_device_not_available). 688 */ 689void math_state_restore(void) 690{ 691 struct task_struct *tsk = current; 692 693 if (!tsk_used_math(tsk)) { 694 local_irq_enable(); 695 /* 696 * does a slab alloc which can sleep 697 */ 698 if (init_fpu(tsk)) { 699 /* 700 * ran out of memory! 701 */ 702 do_group_exit(SIGKILL); 703 return; 704 } 705 local_irq_disable(); 706 } 707 708 __thread_fpu_begin(tsk); 709 710 /* 711 * Paranoid restore. send a SIGSEGV if we fail to restore the state. 712 */ 713 if (unlikely(restore_fpu_checking(tsk))) { 714 drop_init_fpu(tsk); 715 force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk); 716 return; 717 } 718 719 tsk->thread.fpu_counter++; 720} 721EXPORT_SYMBOL_GPL(math_state_restore); 722 723dotraplinkage void 724do_device_not_available(struct pt_regs *regs, long error_code) 725{ 726 enum ctx_state prev_state; 727 728 prev_state = exception_enter(); 729 BUG_ON(use_eager_fpu()); 730 731#ifdef CONFIG_MATH_EMULATION 732 if (read_cr0() & X86_CR0_EM) { 733 struct math_emu_info info = { }; 734 735 conditional_sti(regs); 736 737 info.regs = regs; 738 math_emulate(&info); 739 exception_exit(prev_state); 740 return; 741 } 742#endif 743 math_state_restore(); /* interrupts still off */ 744#ifdef CONFIG_X86_32 745 conditional_sti(regs); 746#endif 747 exception_exit(prev_state); 748} 749NOKPROBE_SYMBOL(do_device_not_available); 750 751#ifdef CONFIG_X86_32 752dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) 753{ 754 siginfo_t info; 755 enum ctx_state prev_state; 756 757 prev_state = exception_enter(); 758 local_irq_enable(); 759 760 info.si_signo = SIGILL; 761 info.si_errno = 0; 762 info.si_code = ILL_BADSTK; 763 info.si_addr = NULL; 764 if (notify_die(DIE_TRAP, "iret exception", regs, error_code, 765 X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) { 766 do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code, 767 &info); 768 } 769 exception_exit(prev_state); 770} 771#endif 772 773/* Set of traps needed for early debugging. */ 774void __init early_trap_init(void) 775{ 776 set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK); 777 /* int3 can be called from all */ 778 set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK); 779#ifdef CONFIG_X86_32 780 set_intr_gate(X86_TRAP_PF, page_fault); 781#endif 782 load_idt(&idt_descr); 783} 784 785void __init early_trap_pf_init(void) 786{ 787#ifdef CONFIG_X86_64 788 set_intr_gate(X86_TRAP_PF, page_fault); 789#endif 790} 791 792void __init trap_init(void) 793{ 794 int i; 795 796#ifdef CONFIG_EISA 797 void __iomem *p = early_ioremap(0x0FFFD9, 4); 798 799 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24)) 800 EISA_bus = 1; 801 early_iounmap(p, 4); 802#endif 803 804 set_intr_gate(X86_TRAP_DE, divide_error); 805 set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK); 806 /* int4 can be called from all */ 807 set_system_intr_gate(X86_TRAP_OF, &overflow); 808 set_intr_gate(X86_TRAP_BR, bounds); 809 set_intr_gate(X86_TRAP_UD, invalid_op); 810 set_intr_gate(X86_TRAP_NM, device_not_available); 811#ifdef CONFIG_X86_32 812 set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS); 813#else 814 set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK); 815#endif 816 set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun); 817 set_intr_gate(X86_TRAP_TS, invalid_TSS); 818 set_intr_gate(X86_TRAP_NP, segment_not_present); 819 set_intr_gate(X86_TRAP_SS, stack_segment); 820 set_intr_gate(X86_TRAP_GP, general_protection); 821 set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug); 822 set_intr_gate(X86_TRAP_MF, coprocessor_error); 823 set_intr_gate(X86_TRAP_AC, alignment_check); 824#ifdef CONFIG_X86_MCE 825 set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK); 826#endif 827 set_intr_gate(X86_TRAP_XF, simd_coprocessor_error); 828 829 /* Reserve all the builtin and the syscall vector: */ 830 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) 831 set_bit(i, used_vectors); 832 833#ifdef CONFIG_IA32_EMULATION 834 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall); 835 set_bit(IA32_SYSCALL_VECTOR, used_vectors); 836#endif 837 838#ifdef CONFIG_X86_32 839 set_system_trap_gate(SYSCALL_VECTOR, &system_call); 840 set_bit(SYSCALL_VECTOR, used_vectors); 841#endif 842 843 /* 844 * Set the IDT descriptor to a fixed read-only location, so that the 845 * "sidt" instruction will not leak the location of the kernel, and 846 * to defend the IDT against arbitrary memory write vulnerabilities. 847 * It will be reloaded in cpu_init() */ 848 __set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO); 849 idt_descr.address = fix_to_virt(FIX_RO_IDT); 850 851 /* 852 * Should be a barrier for any external CPU state: 853 */ 854 cpu_init(); 855 856 x86_init.irqs.trap_init(); 857 858#ifdef CONFIG_X86_64 859 memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16); 860 set_nmi_gate(X86_TRAP_DB, &debug); 861 set_nmi_gate(X86_TRAP_BP, &int3); 862#endif 863} 864