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