2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
5 * Pentium III FXSR, SSE support
6 * Gareth Hughes <gareth@valinux.com>, May 2000
10 * Handle hardware traps and faults.
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 #include <linux/context_tracking.h>
16 #include <linux/interrupt.h>
17 #include <linux/kallsyms.h>
18 #include <linux/spinlock.h>
19 #include <linux/kprobes.h>
20 #include <linux/uaccess.h>
21 #include <linux/kdebug.h>
22 #include <linux/kgdb.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/ptrace.h>
26 #include <linux/uprobes.h>
27 #include <linux/string.h>
28 #include <linux/delay.h>
29 #include <linux/errno.h>
30 #include <linux/kexec.h>
31 #include <linux/sched.h>
32 #include <linux/timer.h>
33 #include <linux/init.h>
34 #include <linux/bug.h>
35 #include <linux/nmi.h>
37 #include <linux/smp.h>
41 #include <linux/ioport.h>
42 #include <linux/eisa.h>
45 #if defined(CONFIG_EDAC)
46 #include <linux/edac.h>
49 #include <asm/kmemcheck.h>
50 #include <asm/stacktrace.h>
51 #include <asm/processor.h>
52 #include <asm/debugreg.h>
53 #include <linux/atomic.h>
54 #include <asm/ftrace.h>
55 #include <asm/traps.h>
58 #include <asm/fpu-internal.h>
60 #include <asm/fixmap.h>
61 #include <asm/mach_traps.h>
62 #include <asm/alternative.h>
65 #include <asm/x86_init.h>
66 #include <asm/pgalloc.h>
67 #include <asm/proto.h>
69 /* No need to be aligned, but done to keep all IDTs defined the same way. */
70 gate_desc debug_idt_table
[NR_VECTORS
] __page_aligned_bss
;
72 #include <asm/processor-flags.h>
73 #include <asm/setup.h>
75 asmlinkage
int system_call(void);
78 /* Must be page-aligned because the real IDT is used in a fixmap. */
79 gate_desc idt_table
[NR_VECTORS
] __page_aligned_bss
;
81 DECLARE_BITMAP(used_vectors
, NR_VECTORS
);
82 EXPORT_SYMBOL_GPL(used_vectors
);
84 static inline void conditional_sti(struct pt_regs
*regs
)
86 if (regs
->flags
& X86_EFLAGS_IF
)
90 static inline void preempt_conditional_sti(struct pt_regs
*regs
)
93 if (regs
->flags
& X86_EFLAGS_IF
)
97 static inline void conditional_cli(struct pt_regs
*regs
)
99 if (regs
->flags
& X86_EFLAGS_IF
)
103 static inline void preempt_conditional_cli(struct pt_regs
*regs
)
105 if (regs
->flags
& X86_EFLAGS_IF
)
110 static nokprobe_inline
int
111 do_trap_no_signal(struct task_struct
*tsk
, int trapnr
, char *str
,
112 struct pt_regs
*regs
, long error_code
)
115 if (regs
->flags
& X86_VM_MASK
) {
117 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
118 * On nmi (interrupt 2), do_trap should not be called.
120 if (trapnr
< X86_TRAP_UD
) {
121 if (!handle_vm86_trap((struct kernel_vm86_regs
*) regs
,
128 if (!user_mode(regs
)) {
129 if (!fixup_exception(regs
)) {
130 tsk
->thread
.error_code
= error_code
;
131 tsk
->thread
.trap_nr
= trapnr
;
132 die(str
, regs
, error_code
);
140 static siginfo_t
*fill_trap_info(struct pt_regs
*regs
, int signr
, int trapnr
,
143 unsigned long siaddr
;
148 return SEND_SIG_PRIV
;
152 siaddr
= uprobe_get_trap_addr(regs
);
156 siaddr
= uprobe_get_trap_addr(regs
);
164 info
->si_signo
= signr
;
166 info
->si_code
= sicode
;
167 info
->si_addr
= (void __user
*)siaddr
;
172 do_trap(int trapnr
, int signr
, char *str
, struct pt_regs
*regs
,
173 long error_code
, siginfo_t
*info
)
175 struct task_struct
*tsk
= current
;
178 if (!do_trap_no_signal(tsk
, trapnr
, str
, regs
, error_code
))
181 * We want error_code and trap_nr set for userspace faults and
182 * kernelspace faults which result in die(), but not
183 * kernelspace faults which are fixed up. die() gives the
184 * process no chance to handle the signal and notice the
185 * kernel fault information, so that won't result in polluting
186 * the information about previously queued, but not yet
187 * delivered, faults. See also do_general_protection below.
189 tsk
->thread
.error_code
= error_code
;
190 tsk
->thread
.trap_nr
= trapnr
;
193 if (show_unhandled_signals
&& unhandled_signal(tsk
, signr
) &&
194 printk_ratelimit()) {
195 pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
196 tsk
->comm
, tsk
->pid
, str
,
197 regs
->ip
, regs
->sp
, error_code
);
198 print_vma_addr(" in ", regs
->ip
);
203 force_sig_info(signr
, info
?: SEND_SIG_PRIV
, tsk
);
205 NOKPROBE_SYMBOL(do_trap
);
207 static void do_error_trap(struct pt_regs
*regs
, long error_code
, char *str
,
208 unsigned long trapnr
, int signr
)
210 enum ctx_state prev_state
= exception_enter();
213 if (notify_die(DIE_TRAP
, str
, regs
, error_code
, trapnr
, signr
) !=
215 conditional_sti(regs
);
216 do_trap(trapnr
, signr
, str
, regs
, error_code
,
217 fill_trap_info(regs
, signr
, trapnr
, &info
));
220 exception_exit(prev_state
);
223 #define DO_ERROR(trapnr, signr, str, name) \
224 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
226 do_error_trap(regs, error_code, str, trapnr, signr); \
229 DO_ERROR(X86_TRAP_DE
, SIGFPE
, "divide error", divide_error
)
230 DO_ERROR(X86_TRAP_OF
, SIGSEGV
, "overflow", overflow
)
231 DO_ERROR(X86_TRAP_BR
, SIGSEGV
, "bounds", bounds
)
232 DO_ERROR(X86_TRAP_UD
, SIGILL
, "invalid opcode", invalid_op
)
233 DO_ERROR(X86_TRAP_OLD_MF
, SIGFPE
, "coprocessor segment overrun",coprocessor_segment_overrun
)
234 DO_ERROR(X86_TRAP_TS
, SIGSEGV
, "invalid TSS", invalid_TSS
)
235 DO_ERROR(X86_TRAP_NP
, SIGBUS
, "segment not present", segment_not_present
)
237 DO_ERROR(X86_TRAP_SS
, SIGBUS
, "stack segment", stack_segment
)
239 DO_ERROR(X86_TRAP_AC
, SIGBUS
, "alignment check", alignment_check
)
242 /* Runs on IST stack */
243 dotraplinkage
void do_stack_segment(struct pt_regs
*regs
, long error_code
)
245 enum ctx_state prev_state
;
247 prev_state
= exception_enter();
248 if (notify_die(DIE_TRAP
, "stack segment", regs
, error_code
,
249 X86_TRAP_SS
, SIGBUS
) != NOTIFY_STOP
) {
250 preempt_conditional_sti(regs
);
251 do_trap(X86_TRAP_SS
, SIGBUS
, "stack segment", regs
, error_code
, NULL
);
252 preempt_conditional_cli(regs
);
254 exception_exit(prev_state
);
257 dotraplinkage
void do_double_fault(struct pt_regs
*regs
, long error_code
)
259 static const char str
[] = "double fault";
260 struct task_struct
*tsk
= current
;
263 /* Return not checked because double check cannot be ignored */
264 notify_die(DIE_TRAP
, str
, regs
, error_code
, X86_TRAP_DF
, SIGSEGV
);
266 tsk
->thread
.error_code
= error_code
;
267 tsk
->thread
.trap_nr
= X86_TRAP_DF
;
269 #ifdef CONFIG_DOUBLEFAULT
270 df_debug(regs
, error_code
);
273 * This is always a kernel trap and never fixable (and thus must
277 die(str
, regs
, error_code
);
282 do_general_protection(struct pt_regs
*regs
, long error_code
)
284 struct task_struct
*tsk
;
285 enum ctx_state prev_state
;
287 prev_state
= exception_enter();
288 conditional_sti(regs
);
291 if (regs
->flags
& X86_VM_MASK
) {
293 handle_vm86_fault((struct kernel_vm86_regs
*) regs
, error_code
);
299 if (!user_mode(regs
)) {
300 if (fixup_exception(regs
))
303 tsk
->thread
.error_code
= error_code
;
304 tsk
->thread
.trap_nr
= X86_TRAP_GP
;
305 if (notify_die(DIE_GPF
, "general protection fault", regs
, error_code
,
306 X86_TRAP_GP
, SIGSEGV
) != NOTIFY_STOP
)
307 die("general protection fault", regs
, error_code
);
311 tsk
->thread
.error_code
= error_code
;
312 tsk
->thread
.trap_nr
= X86_TRAP_GP
;
314 if (show_unhandled_signals
&& unhandled_signal(tsk
, SIGSEGV
) &&
315 printk_ratelimit()) {
316 pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
317 tsk
->comm
, task_pid_nr(tsk
),
318 regs
->ip
, regs
->sp
, error_code
);
319 print_vma_addr(" in ", regs
->ip
);
323 force_sig_info(SIGSEGV
, SEND_SIG_PRIV
, tsk
);
325 exception_exit(prev_state
);
327 NOKPROBE_SYMBOL(do_general_protection
);
329 /* May run on IST stack. */
330 dotraplinkage
void notrace
do_int3(struct pt_regs
*regs
, long error_code
)
332 enum ctx_state prev_state
;
334 #ifdef CONFIG_DYNAMIC_FTRACE
336 * ftrace must be first, everything else may cause a recursive crash.
337 * See note by declaration of modifying_ftrace_code in ftrace.c
339 if (unlikely(atomic_read(&modifying_ftrace_code
)) &&
340 ftrace_int3_handler(regs
))
343 if (poke_int3_handler(regs
))
346 prev_state
= exception_enter();
347 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
348 if (kgdb_ll_trap(DIE_INT3
, "int3", regs
, error_code
, X86_TRAP_BP
,
349 SIGTRAP
) == NOTIFY_STOP
)
351 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
353 #ifdef CONFIG_KPROBES
354 if (kprobe_int3_handler(regs
))
358 if (notify_die(DIE_INT3
, "int3", regs
, error_code
, X86_TRAP_BP
,
359 SIGTRAP
) == NOTIFY_STOP
)
363 * Let others (NMI) know that the debug stack is in use
364 * as we may switch to the interrupt stack.
366 debug_stack_usage_inc();
367 preempt_conditional_sti(regs
);
368 do_trap(X86_TRAP_BP
, SIGTRAP
, "int3", regs
, error_code
, NULL
);
369 preempt_conditional_cli(regs
);
370 debug_stack_usage_dec();
372 exception_exit(prev_state
);
374 NOKPROBE_SYMBOL(do_int3
);
378 * Help handler running on IST stack to switch back to user stack
379 * for scheduling or signal handling. The actual stack switch is done in
382 asmlinkage __visible
struct pt_regs
*sync_regs(struct pt_regs
*eregs
)
384 struct pt_regs
*regs
= eregs
;
385 /* Did already sync */
386 if (eregs
== (struct pt_regs
*)eregs
->sp
)
388 /* Exception from user space */
389 else if (user_mode(eregs
))
390 regs
= task_pt_regs(current
);
392 * Exception from kernel and interrupts are enabled. Move to
393 * kernel process stack.
395 else if (eregs
->flags
& X86_EFLAGS_IF
)
396 regs
= (struct pt_regs
*)(eregs
->sp
-= sizeof(struct pt_regs
));
401 NOKPROBE_SYMBOL(sync_regs
);
405 * Our handling of the processor debug registers is non-trivial.
406 * We do not clear them on entry and exit from the kernel. Therefore
407 * it is possible to get a watchpoint trap here from inside the kernel.
408 * However, the code in ./ptrace.c has ensured that the user can
409 * only set watchpoints on userspace addresses. Therefore the in-kernel
410 * watchpoint trap can only occur in code which is reading/writing
411 * from user space. Such code must not hold kernel locks (since it
412 * can equally take a page fault), therefore it is safe to call
413 * force_sig_info even though that claims and releases locks.
415 * Code in ./signal.c ensures that the debug control register
416 * is restored before we deliver any signal, and therefore that
417 * user code runs with the correct debug control register even though
420 * Being careful here means that we don't have to be as careful in a
421 * lot of more complicated places (task switching can be a bit lazy
422 * about restoring all the debug state, and ptrace doesn't have to
423 * find every occurrence of the TF bit that could be saved away even
426 * May run on IST stack.
428 dotraplinkage
void do_debug(struct pt_regs
*regs
, long error_code
)
430 struct task_struct
*tsk
= current
;
431 enum ctx_state prev_state
;
436 prev_state
= exception_enter();
438 get_debugreg(dr6
, 6);
440 /* Filter out all the reserved bits which are preset to 1 */
441 dr6
&= ~DR6_RESERVED
;
444 * If dr6 has no reason to give us about the origin of this trap,
445 * then it's very likely the result of an icebp/int01 trap.
446 * User wants a sigtrap for that.
448 if (!dr6
&& user_mode(regs
))
451 /* Catch kmemcheck conditions first of all! */
452 if ((dr6
& DR_STEP
) && kmemcheck_trap(regs
))
455 /* DR6 may or may not be cleared by the CPU */
459 * The processor cleared BTF, so don't mark that we need it set.
461 clear_tsk_thread_flag(tsk
, TIF_BLOCKSTEP
);
463 /* Store the virtualized DR6 value */
464 tsk
->thread
.debugreg6
= dr6
;
466 #ifdef CONFIG_KPROBES
467 if (kprobe_debug_handler(regs
))
471 if (notify_die(DIE_DEBUG
, "debug", regs
, (long)&dr6
, error_code
,
472 SIGTRAP
) == NOTIFY_STOP
)
476 * Let others (NMI) know that the debug stack is in use
477 * as we may switch to the interrupt stack.
479 debug_stack_usage_inc();
481 /* It's safe to allow irq's after DR6 has been saved */
482 preempt_conditional_sti(regs
);
484 if (regs
->flags
& X86_VM_MASK
) {
485 handle_vm86_trap((struct kernel_vm86_regs
*) regs
, error_code
,
487 preempt_conditional_cli(regs
);
488 debug_stack_usage_dec();
493 * Single-stepping through system calls: ignore any exceptions in
494 * kernel space, but re-enable TF when returning to user mode.
496 * We already checked v86 mode above, so we can check for kernel mode
497 * by just checking the CPL of CS.
499 if ((dr6
& DR_STEP
) && !user_mode(regs
)) {
500 tsk
->thread
.debugreg6
&= ~DR_STEP
;
501 set_tsk_thread_flag(tsk
, TIF_SINGLESTEP
);
502 regs
->flags
&= ~X86_EFLAGS_TF
;
504 si_code
= get_si_code(tsk
->thread
.debugreg6
);
505 if (tsk
->thread
.debugreg6
& (DR_STEP
| DR_TRAP_BITS
) || user_icebp
)
506 send_sigtrap(tsk
, regs
, error_code
, si_code
);
507 preempt_conditional_cli(regs
);
508 debug_stack_usage_dec();
511 exception_exit(prev_state
);
513 NOKPROBE_SYMBOL(do_debug
);
516 * Note that we play around with the 'TS' bit in an attempt to get
517 * the correct behaviour even in the presence of the asynchronous
520 static void math_error(struct pt_regs
*regs
, int error_code
, int trapnr
)
522 struct task_struct
*task
= current
;
525 char *str
= (trapnr
== X86_TRAP_MF
) ? "fpu exception" :
528 if (notify_die(DIE_TRAP
, str
, regs
, error_code
, trapnr
, SIGFPE
) == NOTIFY_STOP
)
530 conditional_sti(regs
);
532 if (!user_mode_vm(regs
))
534 if (!fixup_exception(regs
)) {
535 task
->thread
.error_code
= error_code
;
536 task
->thread
.trap_nr
= trapnr
;
537 die(str
, regs
, error_code
);
543 * Save the info for the exception handler and clear the error.
546 task
->thread
.trap_nr
= trapnr
;
547 task
->thread
.error_code
= error_code
;
548 info
.si_signo
= SIGFPE
;
550 info
.si_addr
= (void __user
*)uprobe_get_trap_addr(regs
);
551 if (trapnr
== X86_TRAP_MF
) {
552 unsigned short cwd
, swd
;
554 * (~cwd & swd) will mask out exceptions that are not set to unmasked
555 * status. 0x3f is the exception bits in these regs, 0x200 is the
556 * C1 reg you need in case of a stack fault, 0x040 is the stack
557 * fault bit. We should only be taking one exception at a time,
558 * so if this combination doesn't produce any single exception,
559 * then we have a bad program that isn't synchronizing its FPU usage
560 * and it will suffer the consequences since we won't be able to
561 * fully reproduce the context of the exception
563 cwd
= get_fpu_cwd(task
);
564 swd
= get_fpu_swd(task
);
569 * The SIMD FPU exceptions are handled a little differently, as there
570 * is only a single status/control register. Thus, to determine which
571 * unmasked exception was caught we must mask the exception mask bits
572 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
574 unsigned short mxcsr
= get_fpu_mxcsr(task
);
575 err
= ~(mxcsr
>> 7) & mxcsr
;
578 if (err
& 0x001) { /* Invalid op */
580 * swd & 0x240 == 0x040: Stack Underflow
581 * swd & 0x240 == 0x240: Stack Overflow
582 * User must clear the SF bit (0x40) if set
584 info
.si_code
= FPE_FLTINV
;
585 } else if (err
& 0x004) { /* Divide by Zero */
586 info
.si_code
= FPE_FLTDIV
;
587 } else if (err
& 0x008) { /* Overflow */
588 info
.si_code
= FPE_FLTOVF
;
589 } else if (err
& 0x012) { /* Denormal, Underflow */
590 info
.si_code
= FPE_FLTUND
;
591 } else if (err
& 0x020) { /* Precision */
592 info
.si_code
= FPE_FLTRES
;
595 * If we're using IRQ 13, or supposedly even some trap
596 * X86_TRAP_MF implementations, it's possible
597 * we get a spurious trap, which is not an error.
601 force_sig_info(SIGFPE
, &info
, task
);
604 dotraplinkage
void do_coprocessor_error(struct pt_regs
*regs
, long error_code
)
606 enum ctx_state prev_state
;
608 prev_state
= exception_enter();
609 math_error(regs
, error_code
, X86_TRAP_MF
);
610 exception_exit(prev_state
);
614 do_simd_coprocessor_error(struct pt_regs
*regs
, long error_code
)
616 enum ctx_state prev_state
;
618 prev_state
= exception_enter();
619 math_error(regs
, error_code
, X86_TRAP_XF
);
620 exception_exit(prev_state
);
624 do_spurious_interrupt_bug(struct pt_regs
*regs
, long error_code
)
626 conditional_sti(regs
);
628 /* No need to warn about this any longer. */
629 pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
633 asmlinkage __visible
void __attribute__((weak
)) smp_thermal_interrupt(void)
637 asmlinkage __visible
void __attribute__((weak
)) smp_threshold_interrupt(void)
642 * 'math_state_restore()' saves the current math information in the
643 * old math state array, and gets the new ones from the current task
645 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
646 * Don't touch unless you *really* know how it works.
648 * Must be called with kernel preemption disabled (eg with local
649 * local interrupts as in the case of do_device_not_available).
651 void math_state_restore(void)
653 struct task_struct
*tsk
= current
;
655 if (!tsk_used_math(tsk
)) {
658 * does a slab alloc which can sleep
664 do_group_exit(SIGKILL
);
670 __thread_fpu_begin(tsk
);
673 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
675 if (unlikely(restore_fpu_checking(tsk
))) {
677 force_sig_info(SIGSEGV
, SEND_SIG_PRIV
, tsk
);
681 tsk
->thread
.fpu_counter
++;
683 EXPORT_SYMBOL_GPL(math_state_restore
);
686 do_device_not_available(struct pt_regs
*regs
, long error_code
)
688 enum ctx_state prev_state
;
690 prev_state
= exception_enter();
691 BUG_ON(use_eager_fpu());
693 #ifdef CONFIG_MATH_EMULATION
694 if (read_cr0() & X86_CR0_EM
) {
695 struct math_emu_info info
= { };
697 conditional_sti(regs
);
701 exception_exit(prev_state
);
705 math_state_restore(); /* interrupts still off */
707 conditional_sti(regs
);
709 exception_exit(prev_state
);
711 NOKPROBE_SYMBOL(do_device_not_available
);
714 dotraplinkage
void do_iret_error(struct pt_regs
*regs
, long error_code
)
717 enum ctx_state prev_state
;
719 prev_state
= exception_enter();
722 info
.si_signo
= SIGILL
;
724 info
.si_code
= ILL_BADSTK
;
726 if (notify_die(DIE_TRAP
, "iret exception", regs
, error_code
,
727 X86_TRAP_IRET
, SIGILL
) != NOTIFY_STOP
) {
728 do_trap(X86_TRAP_IRET
, SIGILL
, "iret exception", regs
, error_code
,
731 exception_exit(prev_state
);
735 /* Set of traps needed for early debugging. */
736 void __init
early_trap_init(void)
738 set_intr_gate_ist(X86_TRAP_DB
, &debug
, DEBUG_STACK
);
739 /* int3 can be called from all */
740 set_system_intr_gate_ist(X86_TRAP_BP
, &int3
, DEBUG_STACK
);
742 set_intr_gate(X86_TRAP_PF
, page_fault
);
744 load_idt(&idt_descr
);
747 void __init
early_trap_pf_init(void)
750 set_intr_gate(X86_TRAP_PF
, page_fault
);
754 void __init
trap_init(void)
759 void __iomem
*p
= early_ioremap(0x0FFFD9, 4);
761 if (readl(p
) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
766 set_intr_gate(X86_TRAP_DE
, divide_error
);
767 set_intr_gate_ist(X86_TRAP_NMI
, &nmi
, NMI_STACK
);
768 /* int4 can be called from all */
769 set_system_intr_gate(X86_TRAP_OF
, &overflow
);
770 set_intr_gate(X86_TRAP_BR
, bounds
);
771 set_intr_gate(X86_TRAP_UD
, invalid_op
);
772 set_intr_gate(X86_TRAP_NM
, device_not_available
);
774 set_task_gate(X86_TRAP_DF
, GDT_ENTRY_DOUBLEFAULT_TSS
);
776 set_intr_gate_ist(X86_TRAP_DF
, &double_fault
, DOUBLEFAULT_STACK
);
778 set_intr_gate(X86_TRAP_OLD_MF
, coprocessor_segment_overrun
);
779 set_intr_gate(X86_TRAP_TS
, invalid_TSS
);
780 set_intr_gate(X86_TRAP_NP
, segment_not_present
);
781 set_intr_gate_ist(X86_TRAP_SS
, &stack_segment
, STACKFAULT_STACK
);
782 set_intr_gate(X86_TRAP_GP
, general_protection
);
783 set_intr_gate(X86_TRAP_SPURIOUS
, spurious_interrupt_bug
);
784 set_intr_gate(X86_TRAP_MF
, coprocessor_error
);
785 set_intr_gate(X86_TRAP_AC
, alignment_check
);
786 #ifdef CONFIG_X86_MCE
787 set_intr_gate_ist(X86_TRAP_MC
, &machine_check
, MCE_STACK
);
789 set_intr_gate(X86_TRAP_XF
, simd_coprocessor_error
);
791 /* Reserve all the builtin and the syscall vector: */
792 for (i
= 0; i
< FIRST_EXTERNAL_VECTOR
; i
++)
793 set_bit(i
, used_vectors
);
795 #ifdef CONFIG_IA32_EMULATION
796 set_system_intr_gate(IA32_SYSCALL_VECTOR
, ia32_syscall
);
797 set_bit(IA32_SYSCALL_VECTOR
, used_vectors
);
801 set_system_trap_gate(SYSCALL_VECTOR
, &system_call
);
802 set_bit(SYSCALL_VECTOR
, used_vectors
);
806 * Set the IDT descriptor to a fixed read-only location, so that the
807 * "sidt" instruction will not leak the location of the kernel, and
808 * to defend the IDT against arbitrary memory write vulnerabilities.
809 * It will be reloaded in cpu_init() */
810 __set_fixmap(FIX_RO_IDT
, __pa_symbol(idt_table
), PAGE_KERNEL_RO
);
811 idt_descr
.address
= fix_to_virt(FIX_RO_IDT
);
814 * Should be a barrier for any external CPU state:
818 x86_init
.irqs
.trap_init();
821 memcpy(&debug_idt_table
, &idt_table
, IDT_ENTRIES
* 16);
822 set_nmi_gate(X86_TRAP_DB
, &debug
);
823 set_nmi_gate(X86_TRAP_BP
, &int3
);