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 #include <linux/interrupt.h> 13 #include <linux/kallsyms.h> 14 #include <linux/spinlock.h> 15 #include <linux/kprobes.h> 16 #include <linux/uaccess.h> 17 #include <linux/utsname.h> 18 #include <linux/kdebug.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/ptrace.h> 22 #include <linux/string.h> 23 #include <linux/delay.h> 24 #include <linux/errno.h> 25 #include <linux/kexec.h> 26 #include <linux/sched.h> 27 #include <linux/timer.h> 28 #include <linux/init.h> 29 #include <linux/bug.h> 30 #include <linux/nmi.h> 31 #include <linux/mm.h> 32 #include <linux/smp.h> 33 #include <linux/io.h> 34 35 #ifdef CONFIG_EISA 36 #include <linux/ioport.h> 37 #include <linux/eisa.h> 38 #endif 39 40 #ifdef CONFIG_MCA 41 #include <linux/mca.h> 42 #endif 43 44 #if defined(CONFIG_EDAC) 45 #include <linux/edac.h> 46 #endif 47 48 #include <asm/stacktrace.h> 49 #include <asm/processor.h> 50 #include <asm/debugreg.h> 51 #include <asm/atomic.h> 52 #include <asm/system.h> 53 #include <asm/traps.h> 54 #include <asm/desc.h> 55 #include <asm/i387.h> 56 57 #include <mach_traps.h> 58 59 #ifdef CONFIG_X86_64 60 #include <asm/pgalloc.h> 61 #include <asm/proto.h> 62 #include <asm/pda.h> 63 #else 64 #include <asm/processor-flags.h> 65 #include <asm/arch_hooks.h> 66 #include <asm/traps.h> 67 68 #include "cpu/mcheck/mce.h" 69 70 asmlinkage int system_call(void); 71 72 /* Do we ignore FPU interrupts ? */ 73 char ignore_fpu_irq; 74 75 /* 76 * The IDT has to be page-aligned to simplify the Pentium 77 * F0 0F bug workaround.. We have a special link segment 78 * for this. 79 */ 80 gate_desc idt_table[256] 81 __attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, }; 82 #endif 83 84 DECLARE_BITMAP(used_vectors, NR_VECTORS); 85 EXPORT_SYMBOL_GPL(used_vectors); 86 87 static int ignore_nmis; 88 89 static inline void conditional_sti(struct pt_regs *regs) 90 { 91 if (regs->flags & X86_EFLAGS_IF) 92 local_irq_enable(); 93 } 94 95 static inline void preempt_conditional_sti(struct pt_regs *regs) 96 { 97 inc_preempt_count(); 98 if (regs->flags & X86_EFLAGS_IF) 99 local_irq_enable(); 100 } 101 102 static inline void conditional_cli(struct pt_regs *regs) 103 { 104 if (regs->flags & X86_EFLAGS_IF) 105 local_irq_disable(); 106 } 107 108 static inline void preempt_conditional_cli(struct pt_regs *regs) 109 { 110 if (regs->flags & X86_EFLAGS_IF) 111 local_irq_disable(); 112 dec_preempt_count(); 113 } 114 115 #ifdef CONFIG_X86_32 116 static inline void 117 die_if_kernel(const char *str, struct pt_regs *regs, long err) 118 { 119 if (!user_mode_vm(regs)) 120 die(str, regs, err); 121 } 122 123 /* 124 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an 125 * invalid offset set (the LAZY one) and the faulting thread has 126 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS, 127 * we set the offset field correctly and return 1. 128 */ 129 static int lazy_iobitmap_copy(void) 130 { 131 struct thread_struct *thread; 132 struct tss_struct *tss; 133 int cpu; 134 135 cpu = get_cpu(); 136 tss = &per_cpu(init_tss, cpu); 137 thread = ¤t->thread; 138 139 if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY && 140 thread->io_bitmap_ptr) { 141 memcpy(tss->io_bitmap, thread->io_bitmap_ptr, 142 thread->io_bitmap_max); 143 /* 144 * If the previously set map was extending to higher ports 145 * than the current one, pad extra space with 0xff (no access). 146 */ 147 if (thread->io_bitmap_max < tss->io_bitmap_max) { 148 memset((char *) tss->io_bitmap + 149 thread->io_bitmap_max, 0xff, 150 tss->io_bitmap_max - thread->io_bitmap_max); 151 } 152 tss->io_bitmap_max = thread->io_bitmap_max; 153 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET; 154 tss->io_bitmap_owner = thread; 155 put_cpu(); 156 157 return 1; 158 } 159 put_cpu(); 160 161 return 0; 162 } 163 #endif 164 165 static void __kprobes 166 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, 167 long error_code, siginfo_t *info) 168 { 169 struct task_struct *tsk = current; 170 171 #ifdef CONFIG_X86_32 172 if (regs->flags & X86_VM_MASK) { 173 /* 174 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86. 175 * On nmi (interrupt 2), do_trap should not be called. 176 */ 177 if (trapnr < 6) 178 goto vm86_trap; 179 goto trap_signal; 180 } 181 #endif 182 183 if (!user_mode(regs)) 184 goto kernel_trap; 185 186 #ifdef CONFIG_X86_32 187 trap_signal: 188 #endif 189 /* 190 * We want error_code and trap_no set for userspace faults and 191 * kernelspace faults which result in die(), but not 192 * kernelspace faults which are fixed up. die() gives the 193 * process no chance to handle the signal and notice the 194 * kernel fault information, so that won't result in polluting 195 * the information about previously queued, but not yet 196 * delivered, faults. See also do_general_protection below. 197 */ 198 tsk->thread.error_code = error_code; 199 tsk->thread.trap_no = trapnr; 200 201 #ifdef CONFIG_X86_64 202 if (show_unhandled_signals && unhandled_signal(tsk, signr) && 203 printk_ratelimit()) { 204 printk(KERN_INFO 205 "%s[%d] trap %s ip:%lx sp:%lx error:%lx", 206 tsk->comm, tsk->pid, str, 207 regs->ip, regs->sp, error_code); 208 print_vma_addr(" in ", regs->ip); 209 printk("\n"); 210 } 211 #endif 212 213 if (info) 214 force_sig_info(signr, info, tsk); 215 else 216 force_sig(signr, tsk); 217 return; 218 219 kernel_trap: 220 if (!fixup_exception(regs)) { 221 tsk->thread.error_code = error_code; 222 tsk->thread.trap_no = trapnr; 223 die(str, regs, error_code); 224 } 225 return; 226 227 #ifdef CONFIG_X86_32 228 vm86_trap: 229 if (handle_vm86_trap((struct kernel_vm86_regs *) regs, 230 error_code, trapnr)) 231 goto trap_signal; 232 return; 233 #endif 234 } 235 236 #define DO_ERROR(trapnr, signr, str, name) \ 237 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ 238 { \ 239 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ 240 == NOTIFY_STOP) \ 241 return; \ 242 conditional_sti(regs); \ 243 do_trap(trapnr, signr, str, regs, error_code, NULL); \ 244 } 245 246 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ 247 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ 248 { \ 249 siginfo_t info; \ 250 info.si_signo = signr; \ 251 info.si_errno = 0; \ 252 info.si_code = sicode; \ 253 info.si_addr = (void __user *)siaddr; \ 254 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ 255 == NOTIFY_STOP) \ 256 return; \ 257 conditional_sti(regs); \ 258 do_trap(trapnr, signr, str, regs, error_code, &info); \ 259 } 260 261 DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip) 262 DO_ERROR(4, SIGSEGV, "overflow", overflow) 263 DO_ERROR(5, SIGSEGV, "bounds", bounds) 264 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip) 265 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun) 266 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS) 267 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present) 268 #ifdef CONFIG_X86_32 269 DO_ERROR(12, SIGBUS, "stack segment", stack_segment) 270 #endif 271 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0) 272 273 #ifdef CONFIG_X86_64 274 /* Runs on IST stack */ 275 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code) 276 { 277 if (notify_die(DIE_TRAP, "stack segment", regs, error_code, 278 12, SIGBUS) == NOTIFY_STOP) 279 return; 280 preempt_conditional_sti(regs); 281 do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL); 282 preempt_conditional_cli(regs); 283 } 284 285 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) 286 { 287 static const char str[] = "double fault"; 288 struct task_struct *tsk = current; 289 290 /* Return not checked because double check cannot be ignored */ 291 notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV); 292 293 tsk->thread.error_code = error_code; 294 tsk->thread.trap_no = 8; 295 296 /* 297 * This is always a kernel trap and never fixable (and thus must 298 * never return). 299 */ 300 for (;;) 301 die(str, regs, error_code); 302 } 303 #endif 304 305 dotraplinkage void __kprobes 306 do_general_protection(struct pt_regs *regs, long error_code) 307 { 308 struct task_struct *tsk; 309 310 conditional_sti(regs); 311 312 #ifdef CONFIG_X86_32 313 if (lazy_iobitmap_copy()) { 314 /* restart the faulting instruction */ 315 return; 316 } 317 318 if (regs->flags & X86_VM_MASK) 319 goto gp_in_vm86; 320 #endif 321 322 tsk = current; 323 if (!user_mode(regs)) 324 goto gp_in_kernel; 325 326 tsk->thread.error_code = error_code; 327 tsk->thread.trap_no = 13; 328 329 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && 330 printk_ratelimit()) { 331 printk(KERN_INFO 332 "%s[%d] general protection ip:%lx sp:%lx error:%lx", 333 tsk->comm, task_pid_nr(tsk), 334 regs->ip, regs->sp, error_code); 335 print_vma_addr(" in ", regs->ip); 336 printk("\n"); 337 } 338 339 force_sig(SIGSEGV, tsk); 340 return; 341 342 #ifdef CONFIG_X86_32 343 gp_in_vm86: 344 local_irq_enable(); 345 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code); 346 return; 347 #endif 348 349 gp_in_kernel: 350 if (fixup_exception(regs)) 351 return; 352 353 tsk->thread.error_code = error_code; 354 tsk->thread.trap_no = 13; 355 if (notify_die(DIE_GPF, "general protection fault", regs, 356 error_code, 13, SIGSEGV) == NOTIFY_STOP) 357 return; 358 die("general protection fault", regs, error_code); 359 } 360 361 static notrace __kprobes void 362 mem_parity_error(unsigned char reason, struct pt_regs *regs) 363 { 364 printk(KERN_EMERG 365 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", 366 reason, smp_processor_id()); 367 368 printk(KERN_EMERG 369 "You have some hardware problem, likely on the PCI bus.\n"); 370 371 #if defined(CONFIG_EDAC) 372 if (edac_handler_set()) { 373 edac_atomic_assert_error(); 374 return; 375 } 376 #endif 377 378 if (panic_on_unrecovered_nmi) 379 panic("NMI: Not continuing"); 380 381 printk(KERN_EMERG "Dazed and confused, but trying to continue\n"); 382 383 /* Clear and disable the memory parity error line. */ 384 reason = (reason & 0xf) | 4; 385 outb(reason, 0x61); 386 } 387 388 static notrace __kprobes void 389 io_check_error(unsigned char reason, struct pt_regs *regs) 390 { 391 unsigned long i; 392 393 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n"); 394 show_registers(regs); 395 396 /* Re-enable the IOCK line, wait for a few seconds */ 397 reason = (reason & 0xf) | 8; 398 outb(reason, 0x61); 399 400 i = 2000; 401 while (--i) 402 udelay(1000); 403 404 reason &= ~8; 405 outb(reason, 0x61); 406 } 407 408 static notrace __kprobes void 409 unknown_nmi_error(unsigned char reason, struct pt_regs *regs) 410 { 411 if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == 412 NOTIFY_STOP) 413 return; 414 #ifdef CONFIG_MCA 415 /* 416 * Might actually be able to figure out what the guilty party 417 * is: 418 */ 419 if (MCA_bus) { 420 mca_handle_nmi(); 421 return; 422 } 423 #endif 424 printk(KERN_EMERG 425 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", 426 reason, smp_processor_id()); 427 428 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n"); 429 if (panic_on_unrecovered_nmi) 430 panic("NMI: Not continuing"); 431 432 printk(KERN_EMERG "Dazed and confused, but trying to continue\n"); 433 } 434 435 static notrace __kprobes void default_do_nmi(struct pt_regs *regs) 436 { 437 unsigned char reason = 0; 438 int cpu; 439 440 cpu = smp_processor_id(); 441 442 /* Only the BSP gets external NMIs from the system. */ 443 if (!cpu) 444 reason = get_nmi_reason(); 445 446 if (!(reason & 0xc0)) { 447 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT) 448 == NOTIFY_STOP) 449 return; 450 #ifdef CONFIG_X86_LOCAL_APIC 451 /* 452 * Ok, so this is none of the documented NMI sources, 453 * so it must be the NMI watchdog. 454 */ 455 if (nmi_watchdog_tick(regs, reason)) 456 return; 457 if (!do_nmi_callback(regs, cpu)) 458 unknown_nmi_error(reason, regs); 459 #else 460 unknown_nmi_error(reason, regs); 461 #endif 462 463 return; 464 } 465 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP) 466 return; 467 468 /* AK: following checks seem to be broken on modern chipsets. FIXME */ 469 if (reason & 0x80) 470 mem_parity_error(reason, regs); 471 if (reason & 0x40) 472 io_check_error(reason, regs); 473 #ifdef CONFIG_X86_32 474 /* 475 * Reassert NMI in case it became active meanwhile 476 * as it's edge-triggered: 477 */ 478 reassert_nmi(); 479 #endif 480 } 481 482 dotraplinkage notrace __kprobes void 483 do_nmi(struct pt_regs *regs, long error_code) 484 { 485 nmi_enter(); 486 487 inc_irq_stat(__nmi_count); 488 489 if (!ignore_nmis) 490 default_do_nmi(regs); 491 492 nmi_exit(); 493 } 494 495 void stop_nmi(void) 496 { 497 acpi_nmi_disable(); 498 ignore_nmis++; 499 } 500 501 void restart_nmi(void) 502 { 503 ignore_nmis--; 504 acpi_nmi_enable(); 505 } 506 507 /* May run on IST stack. */ 508 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code) 509 { 510 #ifdef CONFIG_KPROBES 511 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) 512 == NOTIFY_STOP) 513 return; 514 #else 515 if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP) 516 == NOTIFY_STOP) 517 return; 518 #endif 519 520 preempt_conditional_sti(regs); 521 do_trap(3, SIGTRAP, "int3", regs, error_code, NULL); 522 preempt_conditional_cli(regs); 523 } 524 525 #ifdef CONFIG_X86_64 526 /* 527 * Help handler running on IST stack to switch back to user stack 528 * for scheduling or signal handling. The actual stack switch is done in 529 * entry.S 530 */ 531 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs) 532 { 533 struct pt_regs *regs = eregs; 534 /* Did already sync */ 535 if (eregs == (struct pt_regs *)eregs->sp) 536 ; 537 /* Exception from user space */ 538 else if (user_mode(eregs)) 539 regs = task_pt_regs(current); 540 /* 541 * Exception from kernel and interrupts are enabled. Move to 542 * kernel process stack. 543 */ 544 else if (eregs->flags & X86_EFLAGS_IF) 545 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs)); 546 if (eregs != regs) 547 *regs = *eregs; 548 return regs; 549 } 550 #endif 551 552 /* 553 * Our handling of the processor debug registers is non-trivial. 554 * We do not clear them on entry and exit from the kernel. Therefore 555 * it is possible to get a watchpoint trap here from inside the kernel. 556 * However, the code in ./ptrace.c has ensured that the user can 557 * only set watchpoints on userspace addresses. Therefore the in-kernel 558 * watchpoint trap can only occur in code which is reading/writing 559 * from user space. Such code must not hold kernel locks (since it 560 * can equally take a page fault), therefore it is safe to call 561 * force_sig_info even though that claims and releases locks. 562 * 563 * Code in ./signal.c ensures that the debug control register 564 * is restored before we deliver any signal, and therefore that 565 * user code runs with the correct debug control register even though 566 * we clear it here. 567 * 568 * Being careful here means that we don't have to be as careful in a 569 * lot of more complicated places (task switching can be a bit lazy 570 * about restoring all the debug state, and ptrace doesn't have to 571 * find every occurrence of the TF bit that could be saved away even 572 * by user code) 573 * 574 * May run on IST stack. 575 */ 576 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) 577 { 578 struct task_struct *tsk = current; 579 unsigned long condition; 580 int si_code; 581 582 get_debugreg(condition, 6); 583 584 /* 585 * The processor cleared BTF, so don't mark that we need it set. 586 */ 587 clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR); 588 tsk->thread.debugctlmsr = 0; 589 590 if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code, 591 SIGTRAP) == NOTIFY_STOP) 592 return; 593 594 /* It's safe to allow irq's after DR6 has been saved */ 595 preempt_conditional_sti(regs); 596 597 /* Mask out spurious debug traps due to lazy DR7 setting */ 598 if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) { 599 if (!tsk->thread.debugreg7) 600 goto clear_dr7; 601 } 602 603 #ifdef CONFIG_X86_32 604 if (regs->flags & X86_VM_MASK) 605 goto debug_vm86; 606 #endif 607 608 /* Save debug status register where ptrace can see it */ 609 tsk->thread.debugreg6 = condition; 610 611 /* 612 * Single-stepping through TF: make sure we ignore any events in 613 * kernel space (but re-enable TF when returning to user mode). 614 */ 615 if (condition & DR_STEP) { 616 if (!user_mode(regs)) 617 goto clear_TF_reenable; 618 } 619 620 si_code = get_si_code(condition); 621 /* Ok, finally something we can handle */ 622 send_sigtrap(tsk, regs, error_code, si_code); 623 624 /* 625 * Disable additional traps. They'll be re-enabled when 626 * the signal is delivered. 627 */ 628 clear_dr7: 629 set_debugreg(0, 7); 630 preempt_conditional_cli(regs); 631 return; 632 633 #ifdef CONFIG_X86_32 634 debug_vm86: 635 /* reenable preemption: handle_vm86_trap() might sleep */ 636 dec_preempt_count(); 637 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1); 638 conditional_cli(regs); 639 return; 640 #endif 641 642 clear_TF_reenable: 643 set_tsk_thread_flag(tsk, TIF_SINGLESTEP); 644 regs->flags &= ~X86_EFLAGS_TF; 645 preempt_conditional_cli(regs); 646 return; 647 } 648 649 #ifdef CONFIG_X86_64 650 static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr) 651 { 652 if (fixup_exception(regs)) 653 return 1; 654 655 notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE); 656 /* Illegal floating point operation in the kernel */ 657 current->thread.trap_no = trapnr; 658 die(str, regs, 0); 659 return 0; 660 } 661 #endif 662 663 /* 664 * Note that we play around with the 'TS' bit in an attempt to get 665 * the correct behaviour even in the presence of the asynchronous 666 * IRQ13 behaviour 667 */ 668 void math_error(void __user *ip) 669 { 670 struct task_struct *task; 671 siginfo_t info; 672 unsigned short cwd, swd, err; 673 674 /* 675 * Save the info for the exception handler and clear the error. 676 */ 677 task = current; 678 save_init_fpu(task); 679 task->thread.trap_no = 16; 680 task->thread.error_code = 0; 681 info.si_signo = SIGFPE; 682 info.si_errno = 0; 683 info.si_addr = ip; 684 /* 685 * (~cwd & swd) will mask out exceptions that are not set to unmasked 686 * status. 0x3f is the exception bits in these regs, 0x200 is the 687 * C1 reg you need in case of a stack fault, 0x040 is the stack 688 * fault bit. We should only be taking one exception at a time, 689 * so if this combination doesn't produce any single exception, 690 * then we have a bad program that isn't synchronizing its FPU usage 691 * and it will suffer the consequences since we won't be able to 692 * fully reproduce the context of the exception 693 */ 694 cwd = get_fpu_cwd(task); 695 swd = get_fpu_swd(task); 696 697 err = swd & ~cwd; 698 699 if (err & 0x001) { /* Invalid op */ 700 /* 701 * swd & 0x240 == 0x040: Stack Underflow 702 * swd & 0x240 == 0x240: Stack Overflow 703 * User must clear the SF bit (0x40) if set 704 */ 705 info.si_code = FPE_FLTINV; 706 } else if (err & 0x004) { /* Divide by Zero */ 707 info.si_code = FPE_FLTDIV; 708 } else if (err & 0x008) { /* Overflow */ 709 info.si_code = FPE_FLTOVF; 710 } else if (err & 0x012) { /* Denormal, Underflow */ 711 info.si_code = FPE_FLTUND; 712 } else if (err & 0x020) { /* Precision */ 713 info.si_code = FPE_FLTRES; 714 } else { 715 /* 716 * If we're using IRQ 13, or supposedly even some trap 16 717 * implementations, it's possible we get a spurious trap... 718 */ 719 return; /* Spurious trap, no error */ 720 } 721 force_sig_info(SIGFPE, &info, task); 722 } 723 724 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) 725 { 726 conditional_sti(regs); 727 728 #ifdef CONFIG_X86_32 729 ignore_fpu_irq = 1; 730 #else 731 if (!user_mode(regs) && 732 kernel_math_error(regs, "kernel x87 math error", 16)) 733 return; 734 #endif 735 736 math_error((void __user *)regs->ip); 737 } 738 739 static void simd_math_error(void __user *ip) 740 { 741 struct task_struct *task; 742 siginfo_t info; 743 unsigned short mxcsr; 744 745 /* 746 * Save the info for the exception handler and clear the error. 747 */ 748 task = current; 749 save_init_fpu(task); 750 task->thread.trap_no = 19; 751 task->thread.error_code = 0; 752 info.si_signo = SIGFPE; 753 info.si_errno = 0; 754 info.si_code = __SI_FAULT; 755 info.si_addr = ip; 756 /* 757 * The SIMD FPU exceptions are handled a little differently, as there 758 * is only a single status/control register. Thus, to determine which 759 * unmasked exception was caught we must mask the exception mask bits 760 * at 0x1f80, and then use these to mask the exception bits at 0x3f. 761 */ 762 mxcsr = get_fpu_mxcsr(task); 763 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) { 764 case 0x000: 765 default: 766 break; 767 case 0x001: /* Invalid Op */ 768 info.si_code = FPE_FLTINV; 769 break; 770 case 0x002: /* Denormalize */ 771 case 0x010: /* Underflow */ 772 info.si_code = FPE_FLTUND; 773 break; 774 case 0x004: /* Zero Divide */ 775 info.si_code = FPE_FLTDIV; 776 break; 777 case 0x008: /* Overflow */ 778 info.si_code = FPE_FLTOVF; 779 break; 780 case 0x020: /* Precision */ 781 info.si_code = FPE_FLTRES; 782 break; 783 } 784 force_sig_info(SIGFPE, &info, task); 785 } 786 787 dotraplinkage void 788 do_simd_coprocessor_error(struct pt_regs *regs, long error_code) 789 { 790 conditional_sti(regs); 791 792 #ifdef CONFIG_X86_32 793 if (cpu_has_xmm) { 794 /* Handle SIMD FPU exceptions on PIII+ processors. */ 795 ignore_fpu_irq = 1; 796 simd_math_error((void __user *)regs->ip); 797 return; 798 } 799 /* 800 * Handle strange cache flush from user space exception 801 * in all other cases. This is undocumented behaviour. 802 */ 803 if (regs->flags & X86_VM_MASK) { 804 handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code); 805 return; 806 } 807 current->thread.trap_no = 19; 808 current->thread.error_code = error_code; 809 die_if_kernel("cache flush denied", regs, error_code); 810 force_sig(SIGSEGV, current); 811 #else 812 if (!user_mode(regs) && 813 kernel_math_error(regs, "kernel simd math error", 19)) 814 return; 815 simd_math_error((void __user *)regs->ip); 816 #endif 817 } 818 819 dotraplinkage void 820 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) 821 { 822 conditional_sti(regs); 823 #if 0 824 /* No need to warn about this any longer. */ 825 printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n"); 826 #endif 827 } 828 829 #ifdef CONFIG_X86_32 830 unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp) 831 { 832 struct desc_struct *gdt = get_cpu_gdt_table(smp_processor_id()); 833 unsigned long base = (kesp - uesp) & -THREAD_SIZE; 834 unsigned long new_kesp = kesp - base; 835 unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT; 836 __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS]; 837 838 /* Set up base for espfix segment */ 839 desc &= 0x00f0ff0000000000ULL; 840 desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) | 841 ((((__u64)base) << 32) & 0xff00000000000000ULL) | 842 ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) | 843 (lim_pages & 0xffff); 844 *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc; 845 846 return new_kesp; 847 } 848 #else 849 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void) 850 { 851 } 852 853 asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void) 854 { 855 } 856 #endif 857 858 /* 859 * 'math_state_restore()' saves the current math information in the 860 * old math state array, and gets the new ones from the current task 861 * 862 * Careful.. There are problems with IBM-designed IRQ13 behaviour. 863 * Don't touch unless you *really* know how it works. 864 * 865 * Must be called with kernel preemption disabled (in this case, 866 * local interrupts are disabled at the call-site in entry.S). 867 */ 868 asmlinkage void math_state_restore(void) 869 { 870 struct thread_info *thread = current_thread_info(); 871 struct task_struct *tsk = thread->task; 872 873 if (!tsk_used_math(tsk)) { 874 local_irq_enable(); 875 /* 876 * does a slab alloc which can sleep 877 */ 878 if (init_fpu(tsk)) { 879 /* 880 * ran out of memory! 881 */ 882 do_group_exit(SIGKILL); 883 return; 884 } 885 local_irq_disable(); 886 } 887 888 clts(); /* Allow maths ops (or we recurse) */ 889 #ifdef CONFIG_X86_32 890 restore_fpu(tsk); 891 #else 892 /* 893 * Paranoid restore. send a SIGSEGV if we fail to restore the state. 894 */ 895 if (unlikely(restore_fpu_checking(tsk))) { 896 stts(); 897 force_sig(SIGSEGV, tsk); 898 return; 899 } 900 #endif 901 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ 902 tsk->fpu_counter++; 903 } 904 EXPORT_SYMBOL_GPL(math_state_restore); 905 906 #ifndef CONFIG_MATH_EMULATION 907 void math_emulate(struct math_emu_info *info) 908 { 909 printk(KERN_EMERG 910 "math-emulation not enabled and no coprocessor found.\n"); 911 printk(KERN_EMERG "killing %s.\n", current->comm); 912 force_sig(SIGFPE, current); 913 schedule(); 914 } 915 #endif /* CONFIG_MATH_EMULATION */ 916 917 dotraplinkage void __kprobes do_device_not_available(struct pt_regs regs) 918 { 919 #ifdef CONFIG_X86_32 920 if (read_cr0() & X86_CR0_EM) { 921 struct math_emu_info info = { }; 922 923 conditional_sti(®s); 924 925 info.regs = ®s; 926 math_emulate(&info); 927 } else { 928 math_state_restore(); /* interrupts still off */ 929 conditional_sti(®s); 930 } 931 #else 932 math_state_restore(); 933 #endif 934 } 935 936 #ifdef CONFIG_X86_32 937 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) 938 { 939 siginfo_t info; 940 local_irq_enable(); 941 942 info.si_signo = SIGILL; 943 info.si_errno = 0; 944 info.si_code = ILL_BADSTK; 945 info.si_addr = 0; 946 if (notify_die(DIE_TRAP, "iret exception", 947 regs, error_code, 32, SIGILL) == NOTIFY_STOP) 948 return; 949 do_trap(32, SIGILL, "iret exception", regs, error_code, &info); 950 } 951 #endif 952 953 void __init trap_init(void) 954 { 955 int i; 956 957 #ifdef CONFIG_EISA 958 void __iomem *p = early_ioremap(0x0FFFD9, 4); 959 960 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24)) 961 EISA_bus = 1; 962 early_iounmap(p, 4); 963 #endif 964 965 set_intr_gate(0, ÷_error); 966 set_intr_gate_ist(1, &debug, DEBUG_STACK); 967 set_intr_gate_ist(2, &nmi, NMI_STACK); 968 /* int3 can be called from all */ 969 set_system_intr_gate_ist(3, &int3, DEBUG_STACK); 970 /* int4 can be called from all */ 971 set_system_intr_gate(4, &overflow); 972 set_intr_gate(5, &bounds); 973 set_intr_gate(6, &invalid_op); 974 set_intr_gate(7, &device_not_available); 975 #ifdef CONFIG_X86_32 976 set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS); 977 #else 978 set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK); 979 #endif 980 set_intr_gate(9, &coprocessor_segment_overrun); 981 set_intr_gate(10, &invalid_TSS); 982 set_intr_gate(11, &segment_not_present); 983 set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK); 984 set_intr_gate(13, &general_protection); 985 set_intr_gate(14, &page_fault); 986 set_intr_gate(15, &spurious_interrupt_bug); 987 set_intr_gate(16, &coprocessor_error); 988 set_intr_gate(17, &alignment_check); 989 #ifdef CONFIG_X86_MCE 990 set_intr_gate_ist(18, &machine_check, MCE_STACK); 991 #endif 992 set_intr_gate(19, &simd_coprocessor_error); 993 994 #ifdef CONFIG_IA32_EMULATION 995 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall); 996 #endif 997 998 #ifdef CONFIG_X86_32 999 if (cpu_has_fxsr) { 1000 printk(KERN_INFO "Enabling fast FPU save and restore... "); 1001 set_in_cr4(X86_CR4_OSFXSR); 1002 printk("done.\n"); 1003 } 1004 if (cpu_has_xmm) { 1005 printk(KERN_INFO 1006 "Enabling unmasked SIMD FPU exception support... "); 1007 set_in_cr4(X86_CR4_OSXMMEXCPT); 1008 printk("done.\n"); 1009 } 1010 1011 set_system_trap_gate(SYSCALL_VECTOR, &system_call); 1012 #endif 1013 1014 /* Reserve all the builtin and the syscall vector: */ 1015 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) 1016 set_bit(i, used_vectors); 1017 1018 #ifdef CONFIG_X86_64 1019 set_bit(IA32_SYSCALL_VECTOR, used_vectors); 1020 #else 1021 set_bit(SYSCALL_VECTOR, used_vectors); 1022 #endif 1023 /* 1024 * Should be a barrier for any external CPU state: 1025 */ 1026 cpu_init(); 1027 1028 #ifdef CONFIG_X86_32 1029 trap_init_hook(); 1030 #endif 1031 } 1032