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 #if defined(CONFIG_EDAC)
  41 #include <linux/edac.h>
  42 #endif
  43
  44 #include <asm/kmemcheck.h>
  45 #include <asm/stacktrace.h>
  46 #include <asm/processor.h>
  47 #include <asm/debugreg.h>
  48 #include <linux/atomic.h>
  49 #include <asm/ftrace.h>
  50 #include <asm/traps.h>
  51 #include <asm/desc.h>
  52 #include <asm/i387.h>
  53 #include <asm/fpu-internal.h>
  54 #include <asm/mce.h>
  55
  56 #include <asm/mach_traps.h>
  57
  58 #ifdef CONFIG_X86_64
  59 #include <asm/x86_init.h>
  60 #include <asm/pgalloc.h>
  61 #include <asm/proto.h>
  62 #else
  63 #include <asm/processor-flags.h>
  64 #include <asm/setup.h>
  65
  66 asmlinkage int system_call(void);
  67
  68 /* Do we ignore FPU interrupts ? */
  69 char ignore_fpu_irq;
  70
  71 /*
  72  * The IDT has to be page-aligned to simplify the Pentium
  73  * F0 0F bug workaround.
  74  */
  75 gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
  76 #endif
  77
  78 DECLARE_BITMAP(used_vectors, NR_VECTORS);
  79 EXPORT_SYMBOL_GPL(used_vectors);
  80
  81 static inline void conditional_sti(struct pt_regs *regs)
  82 {
  83         if (regs->flags & X86_EFLAGS_IF)
  84                 local_irq_enable();
  85 }
  86
  87 static inline void preempt_conditional_sti(struct pt_regs *regs)
  88 {
  89         inc_preempt_count();
  90         if (regs->flags & X86_EFLAGS_IF)
  91                 local_irq_enable();
  92 }
  93
  94 static inline void conditional_cli(struct pt_regs *regs)
  95 {
  96         if (regs->flags & X86_EFLAGS_IF)
  97                 local_irq_disable();
  98 }
  99
 100 static inline void preempt_conditional_cli(struct pt_regs *regs)
 101 {
 102         if (regs->flags & X86_EFLAGS_IF)
 103                 local_irq_disable();
 104         dec_preempt_count();
 105 }
 106
 107 static void __kprobes
 108 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
 109         long error_code, siginfo_t *info)
 110 {
 111         struct task_struct *tsk = current;
 112
 113 #ifdef CONFIG_X86_32
 114         if (regs->flags & X86_VM_MASK) {
 115                 /*
 116                  * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
 117                  * On nmi (interrupt 2), do_trap should not be called.
 118                  */
 119                 if (trapnr < X86_TRAP_UD)
 120                         goto vm86_trap;
 121                 goto trap_signal;
 122         }
 123 #endif
 124
 125         if (!user_mode(regs))
 126                 goto kernel_trap;
 127
 128 #ifdef CONFIG_X86_32
 129 trap_signal:
 130 #endif
 131         /*
 132          * We want error_code and trap_nr set for userspace faults and
 133          * kernelspace faults which result in die(), but not
 134          * kernelspace faults which are fixed up.  die() gives the
 135          * process no chance to handle the signal and notice the
 136          * kernel fault information, so that won't result in polluting
 137          * the information about previously queued, but not yet
 138          * delivered, faults.  See also do_general_protection below.
 139          */
 140         tsk->thread.error_code = error_code;
 141         tsk->thread.trap_nr = trapnr;
 142
 143 #ifdef CONFIG_X86_64
 144         if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
 145             printk_ratelimit()) {
 146                 printk(KERN_INFO
 147                        "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
 148                        tsk->comm, tsk->pid, str,
 149                        regs->ip, regs->sp, error_code);
 150                 print_vma_addr(" in ", regs->ip);
 151                 printk("\n");
 152         }
 153 #endif
 154
 155         if (info)
 156                 force_sig_info(signr, info, tsk);
 157         else
 158                 force_sig(signr, tsk);
 159         return;
 160
 161 kernel_trap:
 162         if (!fixup_exception(regs)) {
 163                 tsk->thread.error_code = error_code;
 164                 tsk->thread.trap_nr = trapnr;
 165                 die(str, regs, error_code);
 166         }
 167         return;
 168
 169 #ifdef CONFIG_X86_32
 170 vm86_trap:
 171         if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
 172                                                 error_code, trapnr))
 173                 goto trap_signal;
 174         return;
 175 #endif
 176 }
 177
 178 #define DO_ERROR(trapnr, signr, str, name)                              \
 179 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 180 {                                                                       \
 181         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 182                                                         == NOTIFY_STOP) \
 183                 return;                                                 \
 184         conditional_sti(regs);                                          \
 185         do_trap(trapnr, signr, str, regs, error_code, NULL);            \
 186 }
 187
 188 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)         \
 189 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 190 {                                                                       \
 191         siginfo_t info;                                                 \
 192         info.si_signo = signr;                                          \
 193         info.si_errno = 0;                                              \
 194         info.si_code = sicode;                                          \
 195         info.si_addr = (void __user *)siaddr;                           \
 196         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 197                                                         == NOTIFY_STOP) \
 198                 return;                                                 \
 199         conditional_sti(regs);                                          \
 200         do_trap(trapnr, signr, str, regs, error_code, &info);           \
 201 }
 202
 203 DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
 204                 regs->ip)
 205 DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
 206 DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds)
 207 DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN,
 208                 regs->ip)
 209 DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",
 210                 coprocessor_segment_overrun)
 211 DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
 212 DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
 213 #ifdef CONFIG_X86_32
 214 DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
 215 #endif
 216 DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check,
 217                 BUS_ADRALN, 0)
 218
 219 #ifdef CONFIG_X86_64
 220 /* Runs on IST stack */
 221 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
 222 {
 223         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
 224                         X86_TRAP_SS, SIGBUS) == NOTIFY_STOP)
 225                 return;
 226         preempt_conditional_sti(regs);
 227         do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
 228         preempt_conditional_cli(regs);
 229 }
 230
 231 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 232 {
 233         static const char str[] = "double fault";
 234         struct task_struct *tsk = current;
 235
 236         /* Return not checked because double check cannot be ignored */
 237         notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 238
 239         tsk->thread.error_code = error_code;
 240         tsk->thread.trap_nr = X86_TRAP_DF;
 241
 242         /*
 243          * This is always a kernel trap and never fixable (and thus must
 244          * never return).
 245          */
 246         for (;;)
 247                 die(str, regs, error_code);
 248 }
 249 #endif
 250
 251 dotraplinkage void __kprobes
 252 do_general_protection(struct pt_regs *regs, long error_code)
 253 {
 254         struct task_struct *tsk;
 255
 256         conditional_sti(regs);
 257
 258 #ifdef CONFIG_X86_32
 259         if (regs->flags & X86_VM_MASK)
 260                 goto gp_in_vm86;
 261 #endif
 262
 263         tsk = current;
 264         if (!user_mode(regs))
 265                 goto gp_in_kernel;
 266
 267         tsk->thread.error_code = error_code;
 268         tsk->thread.trap_nr = X86_TRAP_GP;
 269
 270         if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
 271                         printk_ratelimit()) {
 272                 printk(KERN_INFO
 273                         "%s[%d] general protection ip:%lx sp:%lx error:%lx",
 274                         tsk->comm, task_pid_nr(tsk),
 275                         regs->ip, regs->sp, error_code);
 276                 print_vma_addr(" in ", regs->ip);
 277                 printk("\n");
 278         }
 279
 280         force_sig(SIGSEGV, tsk);
 281         return;
 282
 283 #ifdef CONFIG_X86_32
 284 gp_in_vm86:
 285         local_irq_enable();
 286         handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
 287         return;
 288 #endif
 289
 290 gp_in_kernel:
 291         if (fixup_exception(regs))
 292                 return;
 293
 294         tsk->thread.error_code = error_code;
 295         tsk->thread.trap_nr = X86_TRAP_GP;
 296         if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
 297                         X86_TRAP_GP, SIGSEGV) == NOTIFY_STOP)
 298                 return;
 299         die("general protection fault", regs, error_code);
 300 }
 301
 302 /* May run on IST stack. */
 303 dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
 304 {
 305 #ifdef CONFIG_DYNAMIC_FTRACE
 306         /*
 307          * ftrace must be first, everything else may cause a recursive crash.
 308          * See note by declaration of modifying_ftrace_code in ftrace.c
 309          */
 310         if (unlikely(atomic_read(&modifying_ftrace_code)) &&
 311             ftrace_int3_handler(regs))
 312                 return;
 313 #endif
 314 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 315         if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 316                                 SIGTRAP) == NOTIFY_STOP)
 317                 return;
 318 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 319
 320         if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 321                         SIGTRAP) == NOTIFY_STOP)
 322                 return;
 323
 324         /*
 325          * Let others (NMI) know that the debug stack is in use
 326          * as we may switch to the interrupt stack.
 327          */
 328         debug_stack_usage_inc();
 329         preempt_conditional_sti(regs);
 330         do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
 331         preempt_conditional_cli(regs);
 332         debug_stack_usage_dec();
 333 }
 334
 335 #ifdef CONFIG_X86_64
 336 /*
 337  * Help handler running on IST stack to switch back to user stack
 338  * for scheduling or signal handling. The actual stack switch is done in
 339  * entry.S
 340  */
 341 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
 342 {
 343         struct pt_regs *regs = eregs;
 344         /* Did already sync */
 345         if (eregs == (struct pt_regs *)eregs->sp)
 346                 ;
 347         /* Exception from user space */
 348         else if (user_mode(eregs))
 349                 regs = task_pt_regs(current);
 350         /*
 351          * Exception from kernel and interrupts are enabled. Move to
 352          * kernel process stack.
 353          */
 354         else if (eregs->flags & X86_EFLAGS_IF)
 355                 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
 356         if (eregs != regs)
 357                 *regs = *eregs;
 358         return regs;
 359 }
 360 #endif
 361
 362 /*
 363  * Our handling of the processor debug registers is non-trivial.
 364  * We do not clear them on entry and exit from the kernel. Therefore
 365  * it is possible to get a watchpoint trap here from inside the kernel.
 366  * However, the code in ./ptrace.c has ensured that the user can
 367  * only set watchpoints on userspace addresses. Therefore the in-kernel
 368  * watchpoint trap can only occur in code which is reading/writing
 369  * from user space. Such code must not hold kernel locks (since it
 370  * can equally take a page fault), therefore it is safe to call
 371  * force_sig_info even though that claims and releases locks.
 372  *
 373  * Code in ./signal.c ensures that the debug control register
 374  * is restored before we deliver any signal, and therefore that
 375  * user code runs with the correct debug control register even though
 376  * we clear it here.
 377  *
 378  * Being careful here means that we don't have to be as careful in a
 379  * lot of more complicated places (task switching can be a bit lazy
 380  * about restoring all the debug state, and ptrace doesn't have to
 381  * find every occurrence of the TF bit that could be saved away even
 382  * by user code)
 383  *
 384  * May run on IST stack.
 385  */
 386 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 387 {
 388         struct task_struct *tsk = current;
 389         int user_icebp = 0;
 390         unsigned long dr6;
 391         int si_code;
 392
 393         get_debugreg(dr6, 6);
 394
 395         /* Filter out all the reserved bits which are preset to 1 */
 396         dr6 &= ~DR6_RESERVED;
 397
 398         /*
 399          * If dr6 has no reason to give us about the origin of this trap,
 400          * then it's very likely the result of an icebp/int01 trap.
 401          * User wants a sigtrap for that.
 402          */
 403         if (!dr6 && user_mode(regs))
 404                 user_icebp = 1;
 405
 406         /* Catch kmemcheck conditions first of all! */
 407         if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
 408                 return;
 409
 410         /* DR6 may or may not be cleared by the CPU */
 411         set_debugreg(0, 6);
 412
 413         /*
 414          * The processor cleared BTF, so don't mark that we need it set.
 415          */
 416         clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
 417
 418         /* Store the virtualized DR6 value */
 419         tsk->thread.debugreg6 = dr6;
 420
 421         if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
 422                                                         SIGTRAP) == NOTIFY_STOP)
 423                 return;
 424
 425         /*
 426          * Let others (NMI) know that the debug stack is in use
 427          * as we may switch to the interrupt stack.
 428          */
 429         debug_stack_usage_inc();
 430
 431         /* It's safe to allow irq's after DR6 has been saved */
 432         preempt_conditional_sti(regs);
 433
 434         if (regs->flags & X86_VM_MASK) {
 435                 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
 436                                         X86_TRAP_DB);
 437                 preempt_conditional_cli(regs);
 438                 debug_stack_usage_dec();
 439                 return;
 440         }
 441
 442         /*
 443          * Single-stepping through system calls: ignore any exceptions in
 444          * kernel space, but re-enable TF when returning to user mode.
 445          *
 446          * We already checked v86 mode above, so we can check for kernel mode
 447          * by just checking the CPL of CS.
 448          */
 449         if ((dr6 & DR_STEP) && !user_mode(regs)) {
 450                 tsk->thread.debugreg6 &= ~DR_STEP;
 451                 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
 452                 regs->flags &= ~X86_EFLAGS_TF;
 453         }
 454         si_code = get_si_code(tsk->thread.debugreg6);
 455         if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
 456                 send_sigtrap(tsk, regs, error_code, si_code);
 457         preempt_conditional_cli(regs);
 458         debug_stack_usage_dec();
 459
 460         return;
 461 }
 462
 463 /*
 464  * Note that we play around with the 'TS' bit in an attempt to get
 465  * the correct behaviour even in the presence of the asynchronous
 466  * IRQ13 behaviour
 467  */
 468 void math_error(struct pt_regs *regs, int error_code, int trapnr)
 469 {
 470         struct task_struct *task = current;
 471         siginfo_t info;
 472         unsigned short err;
 473         char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
 474                                                 "simd exception";
 475
 476         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
 477                 return;
 478         conditional_sti(regs);
 479
 480         if (!user_mode_vm(regs))
 481         {
 482                 if (!fixup_exception(regs)) {
 483                         task->thread.error_code = error_code;
 484                         task->thread.trap_nr = trapnr;
 485                         die(str, regs, error_code);
 486                 }
 487                 return;
 488         }
 489
 490         /*
 491          * Save the info for the exception handler and clear the error.
 492          */
 493         save_init_fpu(task);
 494         task->thread.trap_nr = trapnr;
 495         task->thread.error_code = error_code;
 496         info.si_signo = SIGFPE;
 497         info.si_errno = 0;
 498         info.si_addr = (void __user *)regs->ip;
 499         if (trapnr == X86_TRAP_MF) {
 500                 unsigned short cwd, swd;
 501                 /*
 502                  * (~cwd & swd) will mask out exceptions that are not set to unmasked
 503                  * status.  0x3f is the exception bits in these regs, 0x200 is the
 504                  * C1 reg you need in case of a stack fault, 0x040 is the stack
 505                  * fault bit.  We should only be taking one exception at a time,
 506                  * so if this combination doesn't produce any single exception,
 507                  * then we have a bad program that isn't synchronizing its FPU usage
 508                  * and it will suffer the consequences since we won't be able to
 509                  * fully reproduce the context of the exception
 510                  */
 511                 cwd = get_fpu_cwd(task);
 512                 swd = get_fpu_swd(task);
 513
 514                 err = swd & ~cwd;
 515         } else {
 516                 /*
 517                  * The SIMD FPU exceptions are handled a little differently, as there
 518                  * is only a single status/control register.  Thus, to determine which
 519                  * unmasked exception was caught we must mask the exception mask bits
 520                  * at 0x1f80, and then use these to mask the exception bits at 0x3f.
 521                  */
 522                 unsigned short mxcsr = get_fpu_mxcsr(task);
 523                 err = ~(mxcsr >> 7) & mxcsr;
 524         }
 525
 526         if (err & 0x001) {      /* Invalid op */
 527                 /*
 528                  * swd & 0x240 == 0x040: Stack Underflow
 529                  * swd & 0x240 == 0x240: Stack Overflow
 530                  * User must clear the SF bit (0x40) if set
 531                  */
 532                 info.si_code = FPE_FLTINV;
 533         } else if (err & 0x004) { /* Divide by Zero */
 534                 info.si_code = FPE_FLTDIV;
 535         } else if (err & 0x008) { /* Overflow */
 536                 info.si_code = FPE_FLTOVF;
 537         } else if (err & 0x012) { /* Denormal, Underflow */
 538                 info.si_code = FPE_FLTUND;
 539         } else if (err & 0x020) { /* Precision */
 540                 info.si_code = FPE_FLTRES;
 541         } else {
 542                 /*
 543                  * If we're using IRQ 13, or supposedly even some trap
 544                  * X86_TRAP_MF implementations, it's possible
 545                  * we get a spurious trap, which is not an error.
 546                  */
 547                 return;
 548         }
 549         force_sig_info(SIGFPE, &info, task);
 550 }
 551
 552 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 553 {
 554 #ifdef CONFIG_X86_32
 555         ignore_fpu_irq = 1;
 556 #endif
 557
 558         math_error(regs, error_code, X86_TRAP_MF);
 559 }
 560
 561 dotraplinkage void
 562 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 563 {
 564         math_error(regs, error_code, X86_TRAP_XF);
 565 }
 566
 567 dotraplinkage void
 568 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 569 {
 570         conditional_sti(regs);
 571 #if 0
 572         /* No need to warn about this any longer. */
 573         printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
 574 #endif
 575 }
 576
 577 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 578 {
 579 }
 580
 581 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
 582 {
 583 }
 584
 585 /*
 586  * 'math_state_restore()' saves the current math information in the
 587  * old math state array, and gets the new ones from the current task
 588  *
 589  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
 590  * Don't touch unless you *really* know how it works.
 591  *
 592  * Must be called with kernel preemption disabled (eg with local
 593  * local interrupts as in the case of do_device_not_available).
 594  */
 595 void math_state_restore(void)
 596 {
 597         struct task_struct *tsk = current;
 598
 599         if (!tsk_used_math(tsk)) {
 600                 local_irq_enable();
 601                 /*
 602                  * does a slab alloc which can sleep
 603                  */
 604                 if (init_fpu(tsk)) {
 605                         /*
 606                          * ran out of memory!
 607                          */
 608                         do_group_exit(SIGKILL);
 609                         return;
 610                 }
 611                 local_irq_disable();
 612         }
 613
 614         __thread_fpu_begin(tsk);
 615         /*
 616          * Paranoid restore. send a SIGSEGV if we fail to restore the state.
 617          */
 618         if (unlikely(restore_fpu_checking(tsk))) {
 619                 __thread_fpu_end(tsk);
 620                 force_sig(SIGSEGV, tsk);
 621                 return;
 622         }
 623
 624         tsk->fpu_counter++;
 625 }
 626 EXPORT_SYMBOL_GPL(math_state_restore);
 627
 628 dotraplinkage void __kprobes
 629 do_device_not_available(struct pt_regs *regs, long error_code)
 630 {
 631 #ifdef CONFIG_MATH_EMULATION
 632         if (read_cr0() & X86_CR0_EM) {
 633                 struct math_emu_info info = { };
 634
 635                 conditional_sti(regs);
 636
 637                 info.regs = regs;
 638                 math_emulate(&info);
 639                 return;
 640         }
 641 #endif
 642         math_state_restore(); /* interrupts still off */
 643 #ifdef CONFIG_X86_32
 644         conditional_sti(regs);
 645 #endif
 646 }
 647
 648 #ifdef CONFIG_X86_32
 649 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 650 {
 651         siginfo_t info;
 652         local_irq_enable();
 653
 654         info.si_signo = SIGILL;
 655         info.si_errno = 0;
 656         info.si_code = ILL_BADSTK;
 657         info.si_addr = NULL;
 658         if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
 659                         X86_TRAP_IRET, SIGILL) == NOTIFY_STOP)
 660                 return;
 661         do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
 662                 &info);
 663 }
 664 #endif
 665
 666 /* Set of traps needed for early debugging. */
 667 void __init early_trap_init(void)
 668 {
 669         set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
 670         /* int3 can be called from all */
 671         set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
 672         set_intr_gate(X86_TRAP_PF, &page_fault);
 673         load_idt(&idt_descr);
 674 }
 675
 676 void __init trap_init(void)
 677 {
 678         int i;
 679
 680 #ifdef CONFIG_EISA
 681         void __iomem *p = early_ioremap(0x0FFFD9, 4);
 682
 683         if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
 684                 EISA_bus = 1;
 685         early_iounmap(p, 4);
 686 #endif
 687
 688         set_intr_gate(X86_TRAP_DE, &divide_error);
 689         set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
 690         /* int4 can be called from all */
 691         set_system_intr_gate(X86_TRAP_OF, &overflow);
 692         set_intr_gate(X86_TRAP_BR, &bounds);
 693         set_intr_gate(X86_TRAP_UD, &invalid_op);
 694         set_intr_gate(X86_TRAP_NM, &device_not_available);
 695 #ifdef CONFIG_X86_32
 696         set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
 697 #else
 698         set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
 699 #endif
 700         set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
 701         set_intr_gate(X86_TRAP_TS, &invalid_TSS);
 702         set_intr_gate(X86_TRAP_NP, &segment_not_present);
 703         set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
 704         set_intr_gate(X86_TRAP_GP, &general_protection);
 705         set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
 706         set_intr_gate(X86_TRAP_MF, &coprocessor_error);
 707         set_intr_gate(X86_TRAP_AC, &alignment_check);
 708 #ifdef CONFIG_X86_MCE
 709         set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
 710 #endif
 711         set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
 712
 713         /* Reserve all the builtin and the syscall vector: */
 714         for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
 715                 set_bit(i, used_vectors);
 716
 717 #ifdef CONFIG_IA32_EMULATION
 718         set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
 719         set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 720 #endif
 721
 722 #ifdef CONFIG_X86_32
 723         set_system_trap_gate(SYSCALL_VECTOR, &system_call);
 724         set_bit(SYSCALL_VECTOR, used_vectors);
 725 #endif
 726
 727         /*
 728          * Should be a barrier for any external CPU state:
 729          */
 730         cpu_init();
 731
 732         x86_init.irqs.trap_init();
 733
 734 #ifdef CONFIG_X86_64
 735         memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
 736         set_nmi_gate(X86_TRAP_DB, &debug);
 737         set_nmi_gate(X86_TRAP_BP, &int3);
 738 #endif
 739 }