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