arch/x86/kernel/traps.c

   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/kdebug.h>
  18 #include <linux/kgdb.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/kmemcheck.h>
  49 #include <asm/stacktrace.h>
  50 #include <asm/processor.h>
  51 #include <asm/debugreg.h>
  52 #include <linux/atomic.h>
  53 #include <asm/system.h>
  54 #include <asm/traps.h>
  55 #include <asm/desc.h>
  56 #include <asm/i387.h>
  57 #include <asm/mce.h>
  58
  59 #include <asm/mach_traps.h>
  60
  61 #ifdef CONFIG_X86_64
  62 #include <asm/x86_init.h>
  63 #include <asm/pgalloc.h>
  64 #include <asm/proto.h>
  65 #else
  66 #include <asm/processor-flags.h>
  67 #include <asm/setup.h>
  68
  69 asmlinkage int system_call(void);
  70
  71 /* Do we ignore FPU interrupts ? */
  72 char ignore_fpu_irq;
  73
  74 /*
  75  * The IDT has to be page-aligned to simplify the Pentium
  76  * F0 0F bug workaround.
  77  */
  78 gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
  79 #endif
  80
  81 DECLARE_BITMAP(used_vectors, NR_VECTORS);
  82 EXPORT_SYMBOL_GPL(used_vectors);
  83
  84 static inline void conditional_sti(struct pt_regs *regs)
  85 {
  86         if (regs->flags & X86_EFLAGS_IF)
  87                 local_irq_enable();
  88 }
  89
  90 static inline void preempt_conditional_sti(struct pt_regs *regs)
  91 {
  92         inc_preempt_count();
  93         if (regs->flags & X86_EFLAGS_IF)
  94                 local_irq_enable();
  95 }
  96
  97 static inline void conditional_cli(struct pt_regs *regs)
  98 {
  99         if (regs->flags & X86_EFLAGS_IF)
 100                 local_irq_disable();
 101 }
 102
 103 static inline void preempt_conditional_cli(struct pt_regs *regs)
 104 {
 105         if (regs->flags & X86_EFLAGS_IF)
 106                 local_irq_disable();
 107         dec_preempt_count();
 108 }
 109
 110 static void __kprobes
 111 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
 112         long error_code, siginfo_t *info)
 113 {
 114         struct task_struct *tsk = current;
 115
 116 #ifdef CONFIG_X86_32
 117         if (regs->flags & X86_VM_MASK) {
 118                 /*
 119                  * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
 120                  * On nmi (interrupt 2), do_trap should not be called.
 121                  */
 122                 if (trapnr < 6)
 123                         goto vm86_trap;
 124                 goto trap_signal;
 125         }
 126 #endif
 127
 128         if (!user_mode(regs))
 129                 goto kernel_trap;
 130
 131 #ifdef CONFIG_X86_32
 132 trap_signal:
 133 #endif
 134         /*
 135          * We want error_code and trap_no set for userspace faults and
 136          * kernelspace faults which result in die(), but not
 137          * kernelspace faults which are fixed up.  die() gives the
 138          * process no chance to handle the signal and notice the
 139          * kernel fault information, so that won't result in polluting
 140          * the information about previously queued, but not yet
 141          * delivered, faults.  See also do_general_protection below.
 142          */
 143         tsk->thread.error_code = error_code;
 144         tsk->thread.trap_no = trapnr;
 145
 146 #ifdef CONFIG_X86_64
 147         if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
 148             printk_ratelimit()) {
 149                 printk(KERN_INFO
 150                        "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
 151                        tsk->comm, tsk->pid, str,
 152                        regs->ip, regs->sp, error_code);
 153                 print_vma_addr(" in ", regs->ip);
 154                 printk("\n");
 155         }
 156 #endif
 157
 158         if (info)
 159                 force_sig_info(signr, info, tsk);
 160         else
 161                 force_sig(signr, tsk);
 162         return;
 163
 164 kernel_trap:
 165         if (!fixup_exception(regs)) {
 166                 tsk->thread.error_code = error_code;
 167                 tsk->thread.trap_no = trapnr;
 168                 die(str, regs, error_code);
 169         }
 170         return;
 171
 172 #ifdef CONFIG_X86_32
 173 vm86_trap:
 174         if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
 175                                                 error_code, trapnr))
 176                 goto trap_signal;
 177         return;
 178 #endif
 179 }
 180
 181 #define DO_ERROR(trapnr, signr, str, name)                              \
 182 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 183 {                                                                       \
 184         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 185                                                         == NOTIFY_STOP) \
 186                 return;                                                 \
 187         conditional_sti(regs);                                          \
 188         do_trap(trapnr, signr, str, regs, error_code, NULL);            \
 189 }
 190
 191 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)         \
 192 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 193 {                                                                       \
 194         siginfo_t info;                                                 \
 195         info.si_signo = signr;                                          \
 196         info.si_errno = 0;                                              \
 197         info.si_code = sicode;                                          \
 198         info.si_addr = (void __user *)siaddr;                           \
 199         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 200                                                         == NOTIFY_STOP) \
 201                 return;                                                 \
 202         conditional_sti(regs);                                          \
 203         do_trap(trapnr, signr, str, regs, error_code, &info);           \
 204 }
 205
 206 DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
 207 DO_ERROR(4, SIGSEGV, "overflow", overflow)
 208 DO_ERROR(5, SIGSEGV, "bounds", bounds)
 209 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)
 210 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
 211 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
 212 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
 213 #ifdef CONFIG_X86_32
 214 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
 215 #endif
 216 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
 217
 218 #ifdef CONFIG_X86_64
 219 /* Runs on IST stack */
 220 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
 221 {
 222         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
 223                         12, SIGBUS) == NOTIFY_STOP)
 224                 return;
 225         preempt_conditional_sti(regs);
 226         do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
 227         preempt_conditional_cli(regs);
 228 }
 229
 230 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 231 {
 232         static const char str[] = "double fault";
 233         struct task_struct *tsk = current;
 234
 235         /* Return not checked because double check cannot be ignored */
 236         notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
 237
 238         tsk->thread.error_code = error_code;
 239         tsk->thread.trap_no = 8;
 240
 241         /*
 242          * This is always a kernel trap and never fixable (and thus must
 243          * never return).
 244          */
 245         for (;;)
 246                 die(str, regs, error_code);
 247 }
 248 #endif
 249
 250 dotraplinkage void __kprobes
 251 do_general_protection(struct pt_regs *regs, long error_code)
 252 {
 253         struct task_struct *tsk;
 254
 255         conditional_sti(regs);
 256
 257 #ifdef CONFIG_X86_32
 258         if (regs->flags & X86_VM_MASK)
 259                 goto gp_in_vm86;
 260 #endif
 261
 262         tsk = current;
 263         if (!user_mode(regs))
 264                 goto gp_in_kernel;
 265
 266         tsk->thread.error_code = error_code;
 267         tsk->thread.trap_no = 13;
 268
 269         if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
 270                         printk_ratelimit()) {
 271                 printk(KERN_INFO
 272                         "%s[%d] general protection ip:%lx sp:%lx error:%lx",
 273                         tsk->comm, task_pid_nr(tsk),
 274                         regs->ip, regs->sp, error_code);
 275                 print_vma_addr(" in ", regs->ip);
 276                 printk("\n");
 277         }
 278
 279         force_sig(SIGSEGV, tsk);
 280         return;
 281
 282 #ifdef CONFIG_X86_32
 283 gp_in_vm86:
 284         local_irq_enable();
 285         handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
 286         return;
 287 #endif
 288
 289 gp_in_kernel:
 290         if (fixup_exception(regs))
 291                 return;
 292
 293         tsk->thread.error_code = error_code;
 294         tsk->thread.trap_no = 13;
 295         if (notify_die(DIE_GPF, "general protection fault", regs,
 296                                 error_code, 13, SIGSEGV) == NOTIFY_STOP)
 297                 return;
 298         die("general protection fault", regs, error_code);
 299 }
 300
 301 /* May run on IST stack. */
 302 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
 303 {
 304 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 305         if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 306                         == NOTIFY_STOP)
 307                 return;
 308 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 309
 310         if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 311                         == NOTIFY_STOP)
 312                 return;
 313
 314         preempt_conditional_sti(regs);
 315         do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
 316         preempt_conditional_cli(regs);
 317 }
 318
 319 #ifdef CONFIG_X86_64
 320 /*
 321  * Help handler running on IST stack to switch back to user stack
 322  * for scheduling or signal handling. The actual stack switch is done in
 323  * entry.S
 324  */
 325 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
 326 {
 327         struct pt_regs *regs = eregs;
 328         /* Did already sync */
 329         if (eregs == (struct pt_regs *)eregs->sp)
 330                 ;
 331         /* Exception from user space */
 332         else if (user_mode(eregs))
 333                 regs = task_pt_regs(current);
 334         /*
 335          * Exception from kernel and interrupts are enabled. Move to
 336          * kernel process stack.
 337          */
 338         else if (eregs->flags & X86_EFLAGS_IF)
 339                 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
 340         if (eregs != regs)
 341                 *regs = *eregs;
 342         return regs;
 343 }
 344 #endif
 345
 346 /*
 347  * Our handling of the processor debug registers is non-trivial.
 348  * We do not clear them on entry and exit from the kernel. Therefore
 349  * it is possible to get a watchpoint trap here from inside the kernel.
 350  * However, the code in ./ptrace.c has ensured that the user can
 351  * only set watchpoints on userspace addresses. Therefore the in-kernel
 352  * watchpoint trap can only occur in code which is reading/writing
 353  * from user space. Such code must not hold kernel locks (since it
 354  * can equally take a page fault), therefore it is safe to call
 355  * force_sig_info even though that claims and releases locks.
 356  *
 357  * Code in ./signal.c ensures that the debug control register
 358  * is restored before we deliver any signal, and therefore that
 359  * user code runs with the correct debug control register even though
 360  * we clear it here.
 361  *
 362  * Being careful here means that we don't have to be as careful in a
 363  * lot of more complicated places (task switching can be a bit lazy
 364  * about restoring all the debug state, and ptrace doesn't have to
 365  * find every occurrence of the TF bit that could be saved away even
 366  * by user code)
 367  *
 368  * May run on IST stack.
 369  */
 370 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 371 {
 372         struct task_struct *tsk = current;
 373         int user_icebp = 0;
 374         unsigned long dr6;
 375         int si_code;
 376
 377         get_debugreg(dr6, 6);
 378
 379         /* Filter out all the reserved bits which are preset to 1 */
 380         dr6 &= ~DR6_RESERVED;
 381
 382         /*
 383          * If dr6 has no reason to give us about the origin of this trap,
 384          * then it's very likely the result of an icebp/int01 trap.
 385          * User wants a sigtrap for that.
 386          */
 387         if (!dr6 && user_mode(regs))
 388                 user_icebp = 1;
 389
 390         /* Catch kmemcheck conditions first of all! */
 391         if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
 392                 return;
 393
 394         /* DR6 may or may not be cleared by the CPU */
 395         set_debugreg(0, 6);
 396
 397         /*
 398          * The processor cleared BTF, so don't mark that we need it set.
 399          */
 400         clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
 401
 402         /* Store the virtualized DR6 value */
 403         tsk->thread.debugreg6 = dr6;
 404
 405         if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
 406                                                         SIGTRAP) == NOTIFY_STOP)
 407                 return;
 408
 409         /* It's safe to allow irq's after DR6 has been saved */
 410         preempt_conditional_sti(regs);
 411
 412         if (regs->flags & X86_VM_MASK) {
 413                 handle_vm86_trap((struct kernel_vm86_regs *) regs,
 414                                 error_code, 1);
 415                 preempt_conditional_cli(regs);
 416                 return;
 417         }
 418
 419         /*
 420          * Single-stepping through system calls: ignore any exceptions in
 421          * kernel space, but re-enable TF when returning to user mode.
 422          *
 423          * We already checked v86 mode above, so we can check for kernel mode
 424          * by just checking the CPL of CS.
 425          */
 426         if ((dr6 & DR_STEP) && !user_mode(regs)) {
 427                 tsk->thread.debugreg6 &= ~DR_STEP;
 428                 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
 429                 regs->flags &= ~X86_EFLAGS_TF;
 430         }
 431         si_code = get_si_code(tsk->thread.debugreg6);
 432         if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
 433                 send_sigtrap(tsk, regs, error_code, si_code);
 434         preempt_conditional_cli(regs);
 435
 436         return;
 437 }
 438
 439 /*
 440  * Note that we play around with the 'TS' bit in an attempt to get
 441  * the correct behaviour even in the presence of the asynchronous
 442  * IRQ13 behaviour
 443  */
 444 void math_error(struct pt_regs *regs, int error_code, int trapnr)
 445 {
 446         struct task_struct *task = current;
 447         siginfo_t info;
 448         unsigned short err;
 449         char *str = (trapnr == 16) ? "fpu exception" : "simd exception";
 450
 451         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
 452                 return;
 453         conditional_sti(regs);
 454
 455         if (!user_mode_vm(regs))
 456         {
 457                 if (!fixup_exception(regs)) {
 458                         task->thread.error_code = error_code;
 459                         task->thread.trap_no = trapnr;
 460                         die(str, regs, error_code);
 461                 }
 462                 return;
 463         }
 464
 465         /*
 466          * Save the info for the exception handler and clear the error.
 467          */
 468         save_init_fpu(task);
 469         task->thread.trap_no = trapnr;
 470         task->thread.error_code = error_code;
 471         info.si_signo = SIGFPE;
 472         info.si_errno = 0;
 473         info.si_addr = (void __user *)regs->ip;
 474         if (trapnr == 16) {
 475                 unsigned short cwd, swd;
 476                 /*
 477                  * (~cwd & swd) will mask out exceptions that are not set to unmasked
 478                  * status.  0x3f is the exception bits in these regs, 0x200 is the
 479                  * C1 reg you need in case of a stack fault, 0x040 is the stack
 480                  * fault bit.  We should only be taking one exception at a time,
 481                  * so if this combination doesn't produce any single exception,
 482                  * then we have a bad program that isn't synchronizing its FPU usage
 483                  * and it will suffer the consequences since we won't be able to
 484                  * fully reproduce the context of the exception
 485                  */
 486                 cwd = get_fpu_cwd(task);
 487                 swd = get_fpu_swd(task);
 488
 489                 err = swd & ~cwd;
 490         } else {
 491                 /*
 492                  * The SIMD FPU exceptions are handled a little differently, as there
 493                  * is only a single status/control register.  Thus, to determine which
 494                  * unmasked exception was caught we must mask the exception mask bits
 495                  * at 0x1f80, and then use these to mask the exception bits at 0x3f.
 496                  */
 497                 unsigned short mxcsr = get_fpu_mxcsr(task);
 498                 err = ~(mxcsr >> 7) & mxcsr;
 499         }
 500
 501         if (err & 0x001) {      /* Invalid op */
 502                 /*
 503                  * swd & 0x240 == 0x040: Stack Underflow
 504                  * swd & 0x240 == 0x240: Stack Overflow
 505                  * User must clear the SF bit (0x40) if set
 506                  */
 507                 info.si_code = FPE_FLTINV;
 508         } else if (err & 0x004) { /* Divide by Zero */
 509                 info.si_code = FPE_FLTDIV;
 510         } else if (err & 0x008) { /* Overflow */
 511                 info.si_code = FPE_FLTOVF;
 512         } else if (err & 0x012) { /* Denormal, Underflow */
 513                 info.si_code = FPE_FLTUND;
 514         } else if (err & 0x020) { /* Precision */
 515                 info.si_code = FPE_FLTRES;
 516         } else {
 517                 /*
 518                  * If we're using IRQ 13, or supposedly even some trap 16
 519                  * implementations, it's possible we get a spurious trap...
 520                  */
 521                 return;         /* Spurious trap, no error */
 522         }
 523         force_sig_info(SIGFPE, &info, task);
 524 }
 525
 526 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 527 {
 528 #ifdef CONFIG_X86_32
 529         ignore_fpu_irq = 1;
 530 #endif
 531
 532         math_error(regs, error_code, 16);
 533 }
 534
 535 dotraplinkage void
 536 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 537 {
 538         math_error(regs, error_code, 19);
 539 }
 540
 541 dotraplinkage void
 542 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 543 {
 544         conditional_sti(regs);
 545 #if 0
 546         /* No need to warn about this any longer. */
 547         printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
 548 #endif
 549 }
 550
 551 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 552 {
 553 }
 554
 555 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
 556 {
 557 }
 558
 559 /*
 560  * __math_state_restore assumes that cr0.TS is already clear and the
 561  * fpu state is all ready for use.  Used during context switch.
 562  */
 563 void __math_state_restore(void)
 564 {
 565         struct thread_info *thread = current_thread_info();
 566         struct task_struct *tsk = thread->task;
 567
 568         /*
 569          * Paranoid restore. send a SIGSEGV if we fail to restore the state.
 570          */
 571         if (unlikely(restore_fpu_checking(tsk))) {
 572                 stts();
 573                 force_sig(SIGSEGV, tsk);
 574                 return;
 575         }
 576
 577         thread->status |= TS_USEDFPU;   /* So we fnsave on switch_to() */
 578         tsk->fpu_counter++;
 579 }
 580
 581 /*
 582  * 'math_state_restore()' saves the current math information in the
 583  * old math state array, and gets the new ones from the current task
 584  *
 585  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
 586  * Don't touch unless you *really* know how it works.
 587  *
 588  * Must be called with kernel preemption disabled (in this case,
 589  * local interrupts are disabled at the call-site in entry.S).
 590  */
 591 asmlinkage void math_state_restore(void)
 592 {
 593         struct thread_info *thread = current_thread_info();
 594         struct task_struct *tsk = thread->task;
 595
 596         if (!tsk_used_math(tsk)) {
 597                 local_irq_enable();
 598                 /*
 599                  * does a slab alloc which can sleep
 600                  */
 601                 if (init_fpu(tsk)) {
 602                         /*
 603                          * ran out of memory!
 604                          */
 605                         do_group_exit(SIGKILL);
 606                         return;
 607                 }
 608                 local_irq_disable();
 609         }
 610
 611         clts();                         /* Allow maths ops (or we recurse) */
 612
 613         __math_state_restore();
 614 }
 615 EXPORT_SYMBOL_GPL(math_state_restore);
 616
 617 dotraplinkage void __kprobes
 618 do_device_not_available(struct pt_regs *regs, long error_code)
 619 {
 620 #ifdef CONFIG_MATH_EMULATION
 621         if (read_cr0() & X86_CR0_EM) {
 622                 struct math_emu_info info = { };
 623
 624                 conditional_sti(regs);
 625
 626                 info.regs = regs;
 627                 math_emulate(&info);
 628                 return;
 629         }
 630 #endif
 631         math_state_restore(); /* interrupts still off */
 632 #ifdef CONFIG_X86_32
 633         conditional_sti(regs);
 634 #endif
 635 }
 636
 637 #ifdef CONFIG_X86_32
 638 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 639 {
 640         siginfo_t info;
 641         local_irq_enable();
 642
 643         info.si_signo = SIGILL;
 644         info.si_errno = 0;
 645         info.si_code = ILL_BADSTK;
 646         info.si_addr = NULL;
 647         if (notify_die(DIE_TRAP, "iret exception",
 648                         regs, error_code, 32, SIGILL) == NOTIFY_STOP)
 649                 return;
 650         do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
 651 }
 652 #endif
 653
 654 /* Set of traps needed for early debugging. */
 655 void __init early_trap_init(void)
 656 {
 657         set_intr_gate_ist(1, &debug, DEBUG_STACK);
 658         /* int3 can be called from all */
 659         set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
 660         set_intr_gate(14, &page_fault);
 661         load_idt(&idt_descr);
 662 }
 663
 664 void __init trap_init(void)
 665 {
 666         int i;
 667
 668 #ifdef CONFIG_EISA
 669         void __iomem *p = early_ioremap(0x0FFFD9, 4);
 670
 671         if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
 672                 EISA_bus = 1;
 673         early_iounmap(p, 4);
 674 #endif
 675
 676         set_intr_gate(0, &divide_error);
 677         set_intr_gate_ist(2, &nmi, NMI_STACK);
 678         /* int4 can be called from all */
 679         set_system_intr_gate(4, &overflow);
 680         set_intr_gate(5, &bounds);
 681         set_intr_gate(6, &invalid_op);
 682         set_intr_gate(7, &device_not_available);
 683 #ifdef CONFIG_X86_32
 684         set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
 685 #else
 686         set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
 687 #endif
 688         set_intr_gate(9, &coprocessor_segment_overrun);
 689         set_intr_gate(10, &invalid_TSS);
 690         set_intr_gate(11, &segment_not_present);
 691         set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
 692         set_intr_gate(13, &general_protection);
 693         set_intr_gate(15, &spurious_interrupt_bug);
 694         set_intr_gate(16, &coprocessor_error);
 695         set_intr_gate(17, &alignment_check);
 696 #ifdef CONFIG_X86_MCE
 697         set_intr_gate_ist(18, &machine_check, MCE_STACK);
 698 #endif
 699         set_intr_gate(19, &simd_coprocessor_error);
 700
 701         /* Reserve all the builtin and the syscall vector: */
 702         for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
 703                 set_bit(i, used_vectors);
 704
 705 #ifdef CONFIG_IA32_EMULATION
 706         set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
 707         set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 708 #endif
 709
 710 #ifdef CONFIG_X86_32
 711         set_system_trap_gate(SYSCALL_VECTOR, &system_call);
 712         set_bit(SYSCALL_VECTOR, used_vectors);
 713 #endif
 714
 715         /*
 716          * Should be a barrier for any external CPU state:
 717          */
 718         cpu_init();
 719
 720         x86_init.irqs.trap_init();
 721 }