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
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/interrupt.h>
  16 #include <linux/kallsyms.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/kprobes.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/kdebug.h>
  21 #include <linux/kgdb.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/string.h>
  26 #include <linux/delay.h>
  27 #include <linux/errno.h>
  28 #include <linux/kexec.h>
  29 #include <linux/sched.h>
  30 #include <linux/timer.h>
  31 #include <linux/init.h>
  32 #include <linux/bug.h>
  33 #include <linux/nmi.h>
  34 #include <linux/mm.h>
  35 #include <linux/smp.h>
  36 #include <linux/io.h>
  37
  38 #ifdef CONFIG_EISA
  39 #include <linux/ioport.h>
  40 #include <linux/eisa.h>
  41 #endif
  42
  43 #if defined(CONFIG_EDAC)
  44 #include <linux/edac.h>
  45 #endif
  46
  47 #include <asm/kmemcheck.h>
  48 #include <asm/stacktrace.h>
  49 #include <asm/processor.h>
  50 #include <asm/debugreg.h>
  51 #include <linux/atomic.h>
  52 #include <asm/ftrace.h>
  53 #include <asm/traps.h>
  54 #include <asm/desc.h>
  55 #include <asm/i387.h>
  56 #include <asm/fpu-internal.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 < X86_TRAP_UD)
 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_nr 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_nr = trapnr;
 145
 146 #ifdef CONFIG_X86_64
 147         if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
 148             printk_ratelimit()) {
 149                 pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
 150                         tsk->comm, tsk->pid, str,
 151                         regs->ip, regs->sp, error_code);
 152                 print_vma_addr(" in ", regs->ip);
 153                 pr_cont("\n");
 154         }
 155 #endif
 156
 157         if (info)
 158                 force_sig_info(signr, info, tsk);
 159         else
 160                 force_sig(signr, tsk);
 161         return;
 162
 163 kernel_trap:
 164         if (!fixup_exception(regs)) {
 165                 tsk->thread.error_code = error_code;
 166                 tsk->thread.trap_nr = trapnr;
 167                 die(str, regs, error_code);
 168         }
 169         return;
 170
 171 #ifdef CONFIG_X86_32
 172 vm86_trap:
 173         if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
 174                                                 error_code, trapnr))
 175                 goto trap_signal;
 176         return;
 177 #endif
 178 }
 179
 180 #define DO_ERROR(trapnr, signr, str, name)                              \
 181 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 182 {                                                                       \
 183         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 184                                                         == NOTIFY_STOP) \
 185                 return;                                                 \
 186         conditional_sti(regs);                                          \
 187         do_trap(trapnr, signr, str, regs, error_code, NULL);            \
 188 }
 189
 190 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)         \
 191 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 192 {                                                                       \
 193         siginfo_t info;                                                 \
 194         info.si_signo = signr;                                          \
 195         info.si_errno = 0;                                              \
 196         info.si_code = sicode;                                          \
 197         info.si_addr = (void __user *)siaddr;                           \
 198         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
 199                                                         == NOTIFY_STOP) \
 200                 return;                                                 \
 201         conditional_sti(regs);                                          \
 202         do_trap(trapnr, signr, str, regs, error_code, &info);           \
 203 }
 204
 205 DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
 206                 regs->ip)
 207 DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
 208 DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds)
 209 DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN,
 210                 regs->ip)
 211 DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",
 212                 coprocessor_segment_overrun)
 213 DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
 214 DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
 215 #ifdef CONFIG_X86_32
 216 DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
 217 #endif
 218 DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check,
 219                 BUS_ADRALN, 0)
 220
 221 #ifdef CONFIG_X86_64
 222 /* Runs on IST stack */
 223 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
 224 {
 225         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
 226                         X86_TRAP_SS, SIGBUS) == NOTIFY_STOP)
 227                 return;
 228         preempt_conditional_sti(regs);
 229         do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
 230         preempt_conditional_cli(regs);
 231 }
 232
 233 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 234 {
 235         static const char str[] = "double fault";
 236         struct task_struct *tsk = current;
 237
 238         /* Return not checked because double check cannot be ignored */
 239         notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 240
 241         tsk->thread.error_code = error_code;
 242         tsk->thread.trap_nr = X86_TRAP_DF;
 243
 244         /*
 245          * This is always a kernel trap and never fixable (and thus must
 246          * never return).
 247          */
 248         for (;;)
 249                 die(str, regs, error_code);
 250 }
 251 #endif
 252
 253 dotraplinkage void __kprobes
 254 do_general_protection(struct pt_regs *regs, long error_code)
 255 {
 256         struct task_struct *tsk;
 257
 258         conditional_sti(regs);
 259
 260 #ifdef CONFIG_X86_32
 261         if (regs->flags & X86_VM_MASK)
 262                 goto gp_in_vm86;
 263 #endif
 264
 265         tsk = current;
 266         if (!user_mode(regs))
 267                 goto gp_in_kernel;
 268
 269         tsk->thread.error_code = error_code;
 270         tsk->thread.trap_nr = X86_TRAP_GP;
 271
 272         if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
 273                         printk_ratelimit()) {
 274                 pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
 275                         tsk->comm, task_pid_nr(tsk),
 276                         regs->ip, regs->sp, error_code);
 277                 print_vma_addr(" in ", regs->ip);
 278                 pr_cont("\n");
 279         }
 280
 281         force_sig(SIGSEGV, tsk);
 282         return;
 283
 284 #ifdef CONFIG_X86_32
 285 gp_in_vm86:
 286         local_irq_enable();
 287         handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
 288         return;
 289 #endif
 290
 291 gp_in_kernel:
 292         if (fixup_exception(regs))
 293                 return;
 294
 295         tsk->thread.error_code = error_code;
 296         tsk->thread.trap_nr = X86_TRAP_GP;
 297         if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
 298                         X86_TRAP_GP, SIGSEGV) == NOTIFY_STOP)
 299                 return;
 300         die("general protection fault", regs, error_code);
 301 }
 302
 303 /* May run on IST stack. */
 304 dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
 305 {
 306 #ifdef CONFIG_DYNAMIC_FTRACE
 307         /*
 308          * ftrace must be first, everything else may cause a recursive crash.
 309          * See note by declaration of modifying_ftrace_code in ftrace.c
 310          */
 311         if (unlikely(atomic_read(&modifying_ftrace_code)) &&
 312             ftrace_int3_handler(regs))
 313                 return;
 314 #endif
 315 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 316         if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 317                                 SIGTRAP) == NOTIFY_STOP)
 318                 return;
 319 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 320
 321         if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 322                         SIGTRAP) == NOTIFY_STOP)
 323                 return;
 324
 325         /*
 326          * Let others (NMI) know that the debug stack is in use
 327          * as we may switch to the interrupt stack.
 328          */
 329         debug_stack_usage_inc();
 330         preempt_conditional_sti(regs);
 331         do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
 332         preempt_conditional_cli(regs);
 333         debug_stack_usage_dec();
 334 }
 335
 336 #ifdef CONFIG_X86_64
 337 /*
 338  * Help handler running on IST stack to switch back to user stack
 339  * for scheduling or signal handling. The actual stack switch is done in
 340  * entry.S
 341  */
 342 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
 343 {
 344         struct pt_regs *regs = eregs;
 345         /* Did already sync */
 346         if (eregs == (struct pt_regs *)eregs->sp)
 347                 ;
 348         /* Exception from user space */
 349         else if (user_mode(eregs))
 350                 regs = task_pt_regs(current);
 351         /*
 352          * Exception from kernel and interrupts are enabled. Move to
 353          * kernel process stack.
 354          */
 355         else if (eregs->flags & X86_EFLAGS_IF)
 356                 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
 357         if (eregs != regs)
 358                 *regs = *eregs;
 359         return regs;
 360 }
 361 #endif
 362
 363 /*
 364  * Our handling of the processor debug registers is non-trivial.
 365  * We do not clear them on entry and exit from the kernel. Therefore
 366  * it is possible to get a watchpoint trap here from inside the kernel.
 367  * However, the code in ./ptrace.c has ensured that the user can
 368  * only set watchpoints on userspace addresses. Therefore the in-kernel
 369  * watchpoint trap can only occur in code which is reading/writing
 370  * from user space. Such code must not hold kernel locks (since it
 371  * can equally take a page fault), therefore it is safe to call
 372  * force_sig_info even though that claims and releases locks.
 373  *
 374  * Code in ./signal.c ensures that the debug control register
 375  * is restored before we deliver any signal, and therefore that
 376  * user code runs with the correct debug control register even though
 377  * we clear it here.
 378  *
 379  * Being careful here means that we don't have to be as careful in a
 380  * lot of more complicated places (task switching can be a bit lazy
 381  * about restoring all the debug state, and ptrace doesn't have to
 382  * find every occurrence of the TF bit that could be saved away even
 383  * by user code)
 384  *
 385  * May run on IST stack.
 386  */
 387 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 388 {
 389         struct task_struct *tsk = current;
 390         int user_icebp = 0;
 391         unsigned long dr6;
 392         int si_code;
 393
 394         get_debugreg(dr6, 6);
 395
 396         /* Filter out all the reserved bits which are preset to 1 */
 397         dr6 &= ~DR6_RESERVED;
 398
 399         /*
 400          * If dr6 has no reason to give us about the origin of this trap,
 401          * then it's very likely the result of an icebp/int01 trap.
 402          * User wants a sigtrap for that.
 403          */
 404         if (!dr6 && user_mode(regs))
 405                 user_icebp = 1;
 406
 407         /* Catch kmemcheck conditions first of all! */
 408         if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
 409                 return;
 410
 411         /* DR6 may or may not be cleared by the CPU */
 412         set_debugreg(0, 6);
 413
 414         /*
 415          * The processor cleared BTF, so don't mark that we need it set.
 416          */
 417         clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
 418
 419         /* Store the virtualized DR6 value */
 420         tsk->thread.debugreg6 = dr6;
 421
 422         if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
 423                                                         SIGTRAP) == NOTIFY_STOP)
 424                 return;
 425
 426         /*
 427          * Let others (NMI) know that the debug stack is in use
 428          * as we may switch to the interrupt stack.
 429          */
 430         debug_stack_usage_inc();
 431
 432         /* It's safe to allow irq's after DR6 has been saved */
 433         preempt_conditional_sti(regs);
 434
 435         if (regs->flags & X86_VM_MASK) {
 436                 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
 437                                         X86_TRAP_DB);
 438                 preempt_conditional_cli(regs);
 439                 debug_stack_usage_dec();
 440                 return;
 441         }
 442
 443         /*
 444          * Single-stepping through system calls: ignore any exceptions in
 445          * kernel space, but re-enable TF when returning to user mode.
 446          *
 447          * We already checked v86 mode above, so we can check for kernel mode
 448          * by just checking the CPL of CS.
 449          */
 450         if ((dr6 & DR_STEP) && !user_mode(regs)) {
 451                 tsk->thread.debugreg6 &= ~DR_STEP;
 452                 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
 453                 regs->flags &= ~X86_EFLAGS_TF;
 454         }
 455         si_code = get_si_code(tsk->thread.debugreg6);
 456         if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
 457                 send_sigtrap(tsk, regs, error_code, si_code);
 458         preempt_conditional_cli(regs);
 459         debug_stack_usage_dec();
 460
 461         return;
 462 }
 463
 464 /*
 465  * Note that we play around with the 'TS' bit in an attempt to get
 466  * the correct behaviour even in the presence of the asynchronous
 467  * IRQ13 behaviour
 468  */
 469 void math_error(struct pt_regs *regs, int error_code, int trapnr)
 470 {
 471         struct task_struct *task = current;
 472         siginfo_t info;
 473         unsigned short err;
 474         char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
 475                                                 "simd exception";
 476
 477         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
 478                 return;
 479         conditional_sti(regs);
 480
 481         if (!user_mode_vm(regs))
 482         {
 483                 if (!fixup_exception(regs)) {
 484                         task->thread.error_code = error_code;
 485                         task->thread.trap_nr = trapnr;
 486                         die(str, regs, error_code);
 487                 }
 488                 return;
 489         }
 490
 491         /*
 492          * Save the info for the exception handler and clear the error.
 493          */
 494         save_init_fpu(task);
 495         task->thread.trap_nr = trapnr;
 496         task->thread.error_code = error_code;
 497         info.si_signo = SIGFPE;
 498         info.si_errno = 0;
 499         info.si_addr = (void __user *)regs->ip;
 500         if (trapnr == X86_TRAP_MF) {
 501                 unsigned short cwd, swd;
 502                 /*
 503                  * (~cwd & swd) will mask out exceptions that are not set to unmasked
 504                  * status.  0x3f is the exception bits in these regs, 0x200 is the
 505                  * C1 reg you need in case of a stack fault, 0x040 is the stack
 506                  * fault bit.  We should only be taking one exception at a time,
 507                  * so if this combination doesn't produce any single exception,
 508                  * then we have a bad program that isn't synchronizing its FPU usage
 509                  * and it will suffer the consequences since we won't be able to
 510                  * fully reproduce the context of the exception
 511                  */
 512                 cwd = get_fpu_cwd(task);
 513                 swd = get_fpu_swd(task);
 514
 515                 err = swd & ~cwd;
 516         } else {
 517                 /*
 518                  * The SIMD FPU exceptions are handled a little differently, as there
 519                  * is only a single status/control register.  Thus, to determine which
 520                  * unmasked exception was caught we must mask the exception mask bits
 521                  * at 0x1f80, and then use these to mask the exception bits at 0x3f.
 522                  */
 523                 unsigned short mxcsr = get_fpu_mxcsr(task);
 524                 err = ~(mxcsr >> 7) & mxcsr;
 525         }
 526
 527         if (err & 0x001) {      /* Invalid op */
 528                 /*
 529                  * swd & 0x240 == 0x040: Stack Underflow
 530                  * swd & 0x240 == 0x240: Stack Overflow
 531                  * User must clear the SF bit (0x40) if set
 532                  */
 533                 info.si_code = FPE_FLTINV;
 534         } else if (err & 0x004) { /* Divide by Zero */
 535                 info.si_code = FPE_FLTDIV;
 536         } else if (err & 0x008) { /* Overflow */
 537                 info.si_code = FPE_FLTOVF;
 538         } else if (err & 0x012) { /* Denormal, Underflow */
 539                 info.si_code = FPE_FLTUND;
 540         } else if (err & 0x020) { /* Precision */
 541                 info.si_code = FPE_FLTRES;
 542         } else {
 543                 /*
 544                  * If we're using IRQ 13, or supposedly even some trap
 545                  * X86_TRAP_MF implementations, it's possible
 546                  * we get a spurious trap, which is not an error.
 547                  */
 548                 return;
 549         }
 550         force_sig_info(SIGFPE, &info, task);
 551 }
 552
 553 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 554 {
 555 #ifdef CONFIG_X86_32
 556         ignore_fpu_irq = 1;
 557 #endif
 558
 559         math_error(regs, error_code, X86_TRAP_MF);
 560 }
 561
 562 dotraplinkage void
 563 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 564 {
 565         math_error(regs, error_code, X86_TRAP_XF);
 566 }
 567
 568 dotraplinkage void
 569 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 570 {
 571         conditional_sti(regs);
 572 #if 0
 573         /* No need to warn about this any longer. */
 574         pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
 575 #endif
 576 }
 577
 578 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 579 {
 580 }
 581
 582 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
 583 {
 584 }
 585
 586 /*
 587  * 'math_state_restore()' saves the current math information in the
 588  * old math state array, and gets the new ones from the current task
 589  *
 590  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
 591  * Don't touch unless you *really* know how it works.
 592  *
 593  * Must be called with kernel preemption disabled (eg with local
 594  * local interrupts as in the case of do_device_not_available).
 595  */
 596 void math_state_restore(void)
 597 {
 598         struct task_struct *tsk = current;
 599
 600         if (!tsk_used_math(tsk)) {
 601                 local_irq_enable();
 602                 /*
 603                  * does a slab alloc which can sleep
 604                  */
 605                 if (init_fpu(tsk)) {
 606                         /*
 607                          * ran out of memory!
 608                          */
 609                         do_group_exit(SIGKILL);
 610                         return;
 611                 }
 612                 local_irq_disable();
 613         }
 614
 615         __thread_fpu_begin(tsk);
 616
 617         /*
 618          * Paranoid restore. send a SIGSEGV if we fail to restore the state.
 619          */
 620         if (unlikely(restore_fpu_checking(tsk))) {
 621                 drop_init_fpu(tsk);
 622                 force_sig(SIGSEGV, tsk);
 623                 return;
 624         }
 625
 626         tsk->fpu_counter++;
 627 }
 628 EXPORT_SYMBOL_GPL(math_state_restore);
 629
 630 dotraplinkage void __kprobes
 631 do_device_not_available(struct pt_regs *regs, long error_code)
 632 {
 633         BUG_ON(use_xsave());
 634
 635 #ifdef CONFIG_MATH_EMULATION
 636         if (read_cr0() & X86_CR0_EM) {
 637                 struct math_emu_info info = { };
 638
 639                 conditional_sti(regs);
 640
 641                 info.regs = regs;
 642                 math_emulate(&info);
 643                 return;
 644         }
 645 #endif
 646         math_state_restore(); /* interrupts still off */
 647 #ifdef CONFIG_X86_32
 648         conditional_sti(regs);
 649 #endif
 650 }
 651
 652 #ifdef CONFIG_X86_32
 653 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 654 {
 655         siginfo_t info;
 656         local_irq_enable();
 657
 658         info.si_signo = SIGILL;
 659         info.si_errno = 0;
 660         info.si_code = ILL_BADSTK;
 661         info.si_addr = NULL;
 662         if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
 663                         X86_TRAP_IRET, SIGILL) == NOTIFY_STOP)
 664                 return;
 665         do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
 666                 &info);
 667 }
 668 #endif
 669
 670 /* Set of traps needed for early debugging. */
 671 void __init early_trap_init(void)
 672 {
 673         set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
 674         /* int3 can be called from all */
 675         set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
 676         set_intr_gate(X86_TRAP_PF, &page_fault);
 677         load_idt(&idt_descr);
 678 }
 679
 680 void __init trap_init(void)
 681 {
 682         int i;
 683
 684 #ifdef CONFIG_EISA
 685         void __iomem *p = early_ioremap(0x0FFFD9, 4);
 686
 687         if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
 688                 EISA_bus = 1;
 689         early_iounmap(p, 4);
 690 #endif
 691
 692         set_intr_gate(X86_TRAP_DE, &divide_error);
 693         set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
 694         /* int4 can be called from all */
 695         set_system_intr_gate(X86_TRAP_OF, &overflow);
 696         set_intr_gate(X86_TRAP_BR, &bounds);
 697         set_intr_gate(X86_TRAP_UD, &invalid_op);
 698         set_intr_gate(X86_TRAP_NM, &device_not_available);
 699 #ifdef CONFIG_X86_32
 700         set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
 701 #else
 702         set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
 703 #endif
 704         set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
 705         set_intr_gate(X86_TRAP_TS, &invalid_TSS);
 706         set_intr_gate(X86_TRAP_NP, &segment_not_present);
 707         set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
 708         set_intr_gate(X86_TRAP_GP, &general_protection);
 709         set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
 710         set_intr_gate(X86_TRAP_MF, &coprocessor_error);
 711         set_intr_gate(X86_TRAP_AC, &alignment_check);
 712 #ifdef CONFIG_X86_MCE
 713         set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
 714 #endif
 715         set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
 716
 717         /* Reserve all the builtin and the syscall vector: */
 718         for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
 719                 set_bit(i, used_vectors);
 720
 721 #ifdef CONFIG_IA32_EMULATION
 722         set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
 723         set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 724 #endif
 725
 726 #ifdef CONFIG_X86_32
 727         set_system_trap_gate(SYSCALL_VECTOR, &system_call);
 728         set_bit(SYSCALL_VECTOR, used_vectors);
 729 #endif
 730
 731         /*
 732          * Should be a barrier for any external CPU state:
 733          */
 734         cpu_init();
 735
 736         x86_init.irqs.trap_init();
 737
 738 #ifdef CONFIG_X86_64
 739         memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
 740         set_nmi_gate(X86_TRAP_DB, &debug);
 741         set_nmi_gate(X86_TRAP_BP, &int3);
 742 #endif
 743 }