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|
/*
* linux/arch/i386/entry.S
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* entry.S contains the system-call and fault low-level handling routines.
* This also contains the timer-interrupt handler, as well as all interrupts
* and faults that can result in a task-switch.
*
* NOTE: This code handles signal-recognition, which happens every time
* after a timer-interrupt and after each system call.
*
* I changed all the .align's to 4 (16 byte alignment), as that's faster
* on a 486.
*
* Stack layout in 'ret_from_system_call':
* ptrace needs to have all regs on the stack.
* if the order here is changed, it needs to be
* updated in fork.c:copy_process, signal.c:do_signal,
* ptrace.c and ptrace.h
*
* 0(%esp) - %ebx
* 4(%esp) - %ecx
* 8(%esp) - %edx
* C(%esp) - %esi
* 10(%esp) - %edi
* 14(%esp) - %ebp
* 18(%esp) - %eax
* 1C(%esp) - %ds
* 20(%esp) - %es
* 24(%esp) - orig_eax
* 28(%esp) - %eip
* 2C(%esp) - %cs
* 30(%esp) - %eflags
* 34(%esp) - %oldesp
* 38(%esp) - %oldss
*
* "current" is in register %ebx during any slow entries.
*/
#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/errno.h>
#include <asm/segment.h>
#include <asm/smp.h>
#include <asm/page.h>
#include <asm/desc.h>
#include "irq_vectors.h"
#include <xen/interface/xen.h>
#define nr_syscalls ((syscall_table_size)/4)
EBX = 0x00
ECX = 0x04
EDX = 0x08
ESI = 0x0C
EDI = 0x10
EBP = 0x14
EAX = 0x18
DS = 0x1C
ES = 0x20
ORIG_EAX = 0x24
EIP = 0x28
CS = 0x2C
EFLAGS = 0x30
OLDESP = 0x34
OLDSS = 0x38
CF_MASK = 0x00000001
TF_MASK = 0x00000100
IF_MASK = 0x00000200
DF_MASK = 0x00000400
NT_MASK = 0x00004000
VM_MASK = 0x00020000
/* Pseudo-eflags. */
NMI_MASK = 0x80000000
#ifndef CONFIG_XEN
#define DISABLE_INTERRUPTS cli
#define ENABLE_INTERRUPTS sti
#else
/* Offsets into shared_info_t. */
#define evtchn_upcall_pending /* 0 */
#define evtchn_upcall_mask 1
#define sizeof_vcpu_shift 6
#ifdef CONFIG_SMP
#define GET_VCPU_INFO movl TI_cpu(%ebp),%esi ; \
shl $sizeof_vcpu_shift,%esi ; \
addl HYPERVISOR_shared_info,%esi
#else
#define GET_VCPU_INFO movl HYPERVISOR_shared_info,%esi
#endif
#define __DISABLE_INTERRUPTS movb $1,evtchn_upcall_mask(%esi)
#define __ENABLE_INTERRUPTS movb $0,evtchn_upcall_mask(%esi)
#define DISABLE_INTERRUPTS GET_VCPU_INFO ; \
__DISABLE_INTERRUPTS
#define ENABLE_INTERRUPTS GET_VCPU_INFO ; \
__ENABLE_INTERRUPTS
#define __TEST_PENDING testb $0xFF,evtchn_upcall_pending(%esi)
#endif
#ifdef CONFIG_PREEMPT
#define preempt_stop cli
#else
#define preempt_stop
#define resume_kernel restore_nocheck
#endif
#define SAVE_ALL \
cld; \
pushl %es; \
pushl %ds; \
pushl %eax; \
pushl %ebp; \
pushl %edi; \
pushl %esi; \
pushl %edx; \
pushl %ecx; \
pushl %ebx; \
movl $(__USER_DS), %edx; \
movl %edx, %ds; \
movl %edx, %es;
#define RESTORE_INT_REGS \
popl %ebx; \
popl %ecx; \
popl %edx; \
popl %esi; \
popl %edi; \
popl %ebp; \
popl %eax
#define RESTORE_REGS \
RESTORE_INT_REGS; \
1: popl %ds; \
2: popl %es; \
.section .fixup,"ax"; \
3: movl $0,(%esp); \
jmp 1b; \
4: movl $0,(%esp); \
jmp 2b; \
.previous; \
.section __ex_table,"a";\
.align 4; \
.long 1b,3b; \
.long 2b,4b; \
.previous
ENTRY(ret_from_fork)
pushl %eax
call schedule_tail
GET_THREAD_INFO(%ebp)
popl %eax
jmp syscall_exit
/*
* Return to user mode is not as complex as all this looks,
* but we want the default path for a system call return to
* go as quickly as possible which is why some of this is
* less clear than it otherwise should be.
*/
# userspace resumption stub bypassing syscall exit tracing
ALIGN
ret_from_exception:
preempt_stop
ret_from_intr:
GET_THREAD_INFO(%ebp)
movl EFLAGS(%esp), %eax # mix EFLAGS and CS
movb CS(%esp), %al
testl $(VM_MASK | 2), %eax
jz resume_kernel
ENTRY(resume_userspace)
DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
# int/exception return?
jne work_pending
jmp restore_all
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
cli
cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
jnz restore_nocheck
need_resched:
movl TI_flags(%ebp), %ecx # need_resched set ?
testb $_TIF_NEED_RESCHED, %cl
jz restore_all
testl $IF_MASK,EFLAGS(%esp) # interrupts off (exception path) ?
jz restore_all
call preempt_schedule_irq
jmp need_resched
#endif
/* SYSENTER_RETURN points to after the "sysenter" instruction in
the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
# sysenter call handler stub
ENTRY(sysenter_entry)
movl SYSENTER_stack_esp0(%esp),%esp
sysenter_past_esp:
sti
pushl $(__USER_DS)
pushl %ebp
pushfl
pushl $(__USER_CS)
pushl $SYSENTER_RETURN
/*
* Load the potential sixth argument from user stack.
* Careful about security.
*/
cmpl $__PAGE_OFFSET-3,%ebp
jae syscall_fault
1: movl (%ebp),%ebp
.section __ex_table,"a"
.align 4
.long 1b,syscall_fault
.previous
pushl %eax
SAVE_ALL
GET_THREAD_INFO(%ebp)
/* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
jnz syscall_trace_entry
cmpl $(nr_syscalls), %eax
jae syscall_badsys
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp)
DISABLE_INTERRUPTS
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx
jne syscall_exit_work
/* if something modifies registers it must also disable sysexit */
movl EIP(%esp), %edx
movl OLDESP(%esp), %ecx
xorl %ebp,%ebp
#ifdef CONFIG_XEN
__ENABLE_INTERRUPTS
sysexit_scrit: /**** START OF SYSEXIT CRITICAL REGION ****/
__TEST_PENDING
jnz 14f # process more events if necessary...
movl ESI(%esp), %esi
sysexit
14: __DISABLE_INTERRUPTS
sysexit_ecrit: /**** END OF SYSEXIT CRITICAL REGION ****/
push %esp
call evtchn_do_upcall
add $4,%esp
jmp ret_from_intr
#else
sti
sysexit
#endif /* !CONFIG_XEN */
# system call handler stub
ENTRY(system_call)
pushl %eax # save orig_eax
SAVE_ALL
GET_THREAD_INFO(%ebp)
# system call tracing in operation / emulation
/* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
jnz syscall_trace_entry
cmpl $(nr_syscalls), %eax
jae syscall_badsys
syscall_call:
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp) # store the return value
syscall_exit:
DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx # current->work
jne syscall_exit_work
restore_all:
#ifndef CONFIG_XEN
movl EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
# Warning: OLDSS(%esp) contains the wrong/random values if we
# are returning to the kernel.
# See comments in process.c:copy_thread() for details.
movb OLDSS(%esp), %ah
movb CS(%esp), %al
andl $(VM_MASK | (4 << 8) | 3), %eax
cmpl $((4 << 8) | 3), %eax
je ldt_ss # returning to user-space with LDT SS
restore_nocheck:
#else
restore_nocheck:
movl EFLAGS(%esp), %eax
testl $(VM_MASK|NMI_MASK), %eax
jnz hypervisor_iret
shr $9, %eax # EAX[0] == IRET_EFLAGS.IF
GET_VCPU_INFO
andb evtchn_upcall_mask(%esi),%al
andb $1,%al # EAX[0] == IRET_EFLAGS.IF & event_mask
jnz restore_all_enable_events # != 0 => enable event delivery
#endif
RESTORE_REGS
addl $4, %esp
1: iret
.section .fixup,"ax"
iret_exc:
#ifndef CONFIG_XEN
sti
#endif
pushl $0 # no error code
pushl $do_iret_error
jmp error_code
.previous
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
.previous
#ifndef CONFIG_XEN
ldt_ss:
larl OLDSS(%esp), %eax
jnz restore_nocheck
testl $0x00400000, %eax # returning to 32bit stack?
jnz restore_nocheck # allright, normal return
/* If returning to userspace with 16bit stack,
* try to fix the higher word of ESP, as the CPU
* won't restore it.
* This is an "official" bug of all the x86-compatible
* CPUs, which we can try to work around to make
* dosemu and wine happy. */
subl $8, %esp # reserve space for switch16 pointer
cli
movl %esp, %eax
/* Set up the 16bit stack frame with switch32 pointer on top,
* and a switch16 pointer on top of the current frame. */
call setup_x86_bogus_stack
RESTORE_REGS
lss 20+4(%esp), %esp # switch to 16bit stack
1: iret
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
.previous
#else
hypervisor_iret:
andl $~NMI_MASK, EFLAGS(%esp)
RESTORE_REGS
addl $4, %esp
jmp hypercall_page + (__HYPERVISOR_iret * 32)
#endif
# perform work that needs to be done immediately before resumption
ALIGN
work_pending:
testb $_TIF_NEED_RESCHED, %cl
jz work_notifysig
work_resched:
call schedule
DISABLE_INTERRUPTS # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
movl TI_flags(%ebp), %ecx
andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
# than syscall tracing?
jz restore_all
testb $_TIF_NEED_RESCHED, %cl
jnz work_resched
work_notifysig: # deal with pending signals and
# notify-resume requests
testl $VM_MASK, EFLAGS(%esp)
movl %esp, %eax
jne work_notifysig_v86 # returning to kernel-space or
# vm86-space
xorl %edx, %edx
call do_notify_resume
jmp resume_userspace
ALIGN
work_notifysig_v86:
#ifdef CONFIG_VM86
pushl %ecx # save ti_flags for do_notify_resume
call save_v86_state # %eax contains pt_regs pointer
popl %ecx
movl %eax, %esp
xorl %edx, %edx
call do_notify_resume
jmp resume_userspace
#endif
# perform syscall exit tracing
ALIGN
syscall_trace_entry:
movl $-ENOSYS,EAX(%esp)
movl %esp, %eax
xorl %edx,%edx
call do_syscall_trace
cmpl $0, %eax
jne resume_userspace # ret != 0 -> running under PTRACE_SYSEMU,
# so must skip actual syscall
movl ORIG_EAX(%esp), %eax
cmpl $(nr_syscalls), %eax
jnae syscall_call
jmp syscall_exit
# perform syscall exit tracing
ALIGN
syscall_exit_work:
testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
jz work_pending
ENABLE_INTERRUPTS # could let do_syscall_trace() call
# schedule() instead
movl %esp, %eax
movl $1, %edx
call do_syscall_trace
jmp resume_userspace
ALIGN
syscall_fault:
pushl %eax # save orig_eax
SAVE_ALL
GET_THREAD_INFO(%ebp)
movl $-EFAULT,EAX(%esp)
jmp resume_userspace
ALIGN
syscall_badsys:
movl $-ENOSYS,EAX(%esp)
jmp resume_userspace
#ifndef CONFIG_XEN
#define FIXUP_ESPFIX_STACK \
movl %esp, %eax; \
/* switch to 32bit stack using the pointer on top of 16bit stack */ \
lss %ss:CPU_16BIT_STACK_SIZE-8, %esp; \
/* copy data from 16bit stack to 32bit stack */ \
call fixup_x86_bogus_stack; \
/* put ESP to the proper location */ \
movl %eax, %esp;
#define UNWIND_ESPFIX_STACK \
pushl %eax; \
movl %ss, %eax; \
/* see if on 16bit stack */ \
cmpw $__ESPFIX_SS, %ax; \
jne 28f; \
movl $__KERNEL_DS, %edx; \
movl %edx, %ds; \
movl %edx, %es; \
/* switch to 32bit stack */ \
FIXUP_ESPFIX_STACK \
28: popl %eax;
/*
* Build the entry stubs and pointer table with
* some assembler magic.
*/
.data
ENTRY(interrupt)
.text
vector=0
ENTRY(irq_entries_start)
.rept NR_IRQS
ALIGN
1: pushl $~(vector)
jmp common_interrupt
.data
.long 1b
.text
vector=vector+1
.endr
ALIGN
common_interrupt:
SAVE_ALL
movl %esp,%eax
call do_IRQ
jmp ret_from_intr
#define BUILD_INTERRUPT(name, nr) \
ENTRY(name) \
pushl $~(nr); \
SAVE_ALL \
movl %esp,%eax; \
call smp_/**/name; \
jmp ret_from_intr;
/* The include is where all of the SMP etc. interrupts come from */
#include "entry_arch.h"
#else
#define UNWIND_ESPFIX_STACK
#endif
ENTRY(divide_error)
pushl $0 # no error code
pushl $do_divide_error
ALIGN
error_code:
pushl %ds
pushl %eax
xorl %eax, %eax
pushl %ebp
pushl %edi
pushl %esi
pushl %edx
decl %eax # eax = -1
pushl %ecx
pushl %ebx
cld
pushl %es
UNWIND_ESPFIX_STACK
popl %ecx
movl ES(%esp), %edi # get the function address
movl ORIG_EAX(%esp), %edx # get the error code
movl %eax, ORIG_EAX(%esp)
movl %ecx, ES(%esp)
movl $(__USER_DS), %ecx
movl %ecx, %ds
movl %ecx, %es
movl %esp,%eax # pt_regs pointer
call *%edi
jmp ret_from_exception
#ifdef CONFIG_XEN
# A note on the "critical region" in our callback handler.
# We want to avoid stacking callback handlers due to events occurring
# during handling of the last event. To do this, we keep events disabled
# until we've done all processing. HOWEVER, we must enable events before
# popping the stack frame (can't be done atomically) and so it would still
# be possible to get enough handler activations to overflow the stack.
# Although unlikely, bugs of that kind are hard to track down, so we'd
# like to avoid the possibility.
# So, on entry to the handler we detect whether we interrupted an
# existing activation in its critical region -- if so, we pop the current
# activation and restart the handler using the previous one.
#
# The sysexit critical region is slightly different. sysexit
# atomically removes the entire stack frame. If we interrupt in the
# critical region we know that the entire frame is present and correct
# so we can simply throw away the new one.
ENTRY(hypervisor_callback)
pushl %eax
SAVE_ALL
movl EIP(%esp),%eax
cmpl $scrit,%eax
jb 11f
cmpl $ecrit,%eax
jb critical_region_fixup
cmpl $sysexit_scrit,%eax
jb 11f
cmpl $sysexit_ecrit,%eax
ja 11f
addl $0x34,%esp # Remove cs...ebx from stack frame.
11: push %esp
call evtchn_do_upcall
add $4,%esp
jmp ret_from_intr
ALIGN
restore_all_enable_events:
__ENABLE_INTERRUPTS
scrit: /**** START OF CRITICAL REGION ****/
__TEST_PENDING
jnz 14f # process more events if necessary...
RESTORE_REGS
addl $4, %esp
1: iret
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
.previous
14: __DISABLE_INTERRUPTS
jmp 11b
ecrit: /**** END OF CRITICAL REGION ****/
# [How we do the fixup]. We want to merge the current stack frame with the
# just-interrupted frame. How we do this depends on where in the critical
# region the interrupted handler was executing, and so how many saved
# registers are in each frame. We do this quickly using the lookup table
# 'critical_fixup_table'. For each byte offset in the critical region, it
# provides the number of bytes which have already been popped from the
# interrupted stack frame.
critical_region_fixup:
addl $critical_fixup_table-scrit,%eax
movzbl (%eax),%eax # %eax contains num bytes popped
cmpb $0xff,%al # 0xff => vcpu_info critical region
jne 15f
GET_THREAD_INFO(%ebp)
xorl %eax,%eax
15: mov %esp,%esi
add %eax,%esi # %esi points at end of src region
mov %esp,%edi
add $0x34,%edi # %edi points at end of dst region
mov %eax,%ecx
shr $2,%ecx # convert words to bytes
je 17f # skip loop if nothing to copy
16: subl $4,%esi # pre-decrementing copy loop
subl $4,%edi
movl (%esi),%eax
movl %eax,(%edi)
loop 16b
17: movl %edi,%esp # final %edi is top of merged stack
jmp 11b
critical_fixup_table:
.byte 0xff,0xff,0xff # testb $0xff,(%esi) = __TEST_PENDING
.byte 0xff,0xff # jnz 14f
.byte 0x00 # pop %ebx
.byte 0x04 # pop %ecx
.byte 0x08 # pop %edx
.byte 0x0c # pop %esi
.byte 0x10 # pop %edi
.byte 0x14 # pop %ebp
.byte 0x18 # pop %eax
.byte 0x1c # pop %ds
.byte 0x20 # pop %es
.byte 0x24,0x24,0x24 # add $4,%esp
.byte 0x28 # iret
.byte 0xff,0xff,0xff,0xff # movb $1,1(%esi)
.byte 0x00,0x00 # jmp 11b
# Hypervisor uses this for application faults while it executes.
# We get here for two reasons:
# 1. Fault while reloading DS, ES, FS or GS
# 2. Fault while executing IRET
# Category 1 we fix up by reattempting the load, and zeroing the segment
# register if the load fails.
# Category 2 we fix up by jumping to do_iret_error. We cannot use the
# normal Linux return path in this case because if we use the IRET hypercall
# to pop the stack frame we end up in an infinite loop of failsafe callbacks.
# We distinguish between categories by maintaining a status value in EAX.
ENTRY(failsafe_callback)
pushl %eax
movl $1,%eax
1: mov 4(%esp),%ds
2: mov 8(%esp),%es
3: mov 12(%esp),%fs
4: mov 16(%esp),%gs
testl %eax,%eax
popl %eax
jz 5f
addl $16,%esp # EAX != 0 => Category 2 (Bad IRET)
jmp iret_exc
5: addl $16,%esp # EAX == 0 => Category 1 (Bad segment)
pushl $0
SAVE_ALL
jmp ret_from_exception
.section .fixup,"ax"; \
6: xorl %eax,%eax; \
movl %eax,4(%esp); \
jmp 1b; \
7: xorl %eax,%eax; \
movl %eax,8(%esp); \
jmp 2b; \
8: xorl %eax,%eax; \
movl %eax,12(%esp); \
jmp 3b; \
9: xorl %eax,%eax; \
movl %eax,16(%esp); \
jmp 4b; \
.previous; \
.section __ex_table,"a"; \
.align 4; \
.long 1b,6b; \
.long 2b,7b; \
.long 3b,8b; \
.long 4b,9b; \
.previous
#endif
ENTRY(coprocessor_error)
pushl $0
pushl $do_coprocessor_error
jmp error_code
ENTRY(simd_coprocessor_error)
pushl $0
pushl $do_simd_coprocessor_error
jmp error_code
ENTRY(device_not_available)
pushl $-1 # mark this as an int
SAVE_ALL
#ifndef CONFIG_XEN
movl %cr0, %eax
testl $0x4, %eax # EM (math emulation bit)
je device_available_emulate
pushl $0 # temporary storage for ORIG_EIP
call math_emulate
addl $4, %esp
jmp ret_from_exception
device_available_emulate:
#endif
preempt_stop
call math_state_restore
jmp ret_from_exception
#ifndef CONFIG_XEN
/*
* Debug traps and NMI can happen at the one SYSENTER instruction
* that sets up the real kernel stack. Check here, since we can't
* allow the wrong stack to be used.
*
* "SYSENTER_stack_esp0+12" is because the NMI/debug handler will have
* already pushed 3 words if it hits on the sysenter instruction:
* eflags, cs and eip.
*
* We just load the right stack, and push the three (known) values
* by hand onto the new stack - while updating the return eip past
* the instruction that would have done it for sysenter.
*/
#define FIX_STACK(offset, ok, label) \
cmpw $__KERNEL_CS,4(%esp); \
jne ok; \
label: \
movl SYSENTER_stack_esp0+offset(%esp),%esp; \
pushfl; \
pushl $__KERNEL_CS; \
pushl $sysenter_past_esp
#endif /* CONFIG_XEN */
KPROBE_ENTRY(debug)
#ifndef CONFIG_XEN
cmpl $sysenter_entry,(%esp)
jne debug_stack_correct
FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
debug_stack_correct:
#endif /* !CONFIG_XEN */
pushl $-1 # mark this as an int
SAVE_ALL
xorl %edx,%edx # error code 0
movl %esp,%eax # pt_regs pointer
call do_debug
jmp ret_from_exception
.previous .text
#ifndef CONFIG_XEN
/*
* NMI is doubly nasty. It can happen _while_ we're handling
* a debug fault, and the debug fault hasn't yet been able to
* clear up the stack. So we first check whether we got an
* NMI on the sysenter entry path, but after that we need to
* check whether we got an NMI on the debug path where the debug
* fault happened on the sysenter path.
*/
ENTRY(nmi)
pushl %eax
movl %ss, %eax
cmpw $__ESPFIX_SS, %ax
popl %eax
je nmi_16bit_stack
cmpl $sysenter_entry,(%esp)
je nmi_stack_fixup
pushl %eax
movl %esp,%eax
/* Do not access memory above the end of our stack page,
* it might not exist.
*/
andl $(THREAD_SIZE-1),%eax
cmpl $(THREAD_SIZE-20),%eax
popl %eax
jae nmi_stack_correct
cmpl $sysenter_entry,12(%esp)
je nmi_debug_stack_check
nmi_stack_correct:
pushl %eax
SAVE_ALL
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_nmi
jmp restore_all
nmi_stack_fixup:
FIX_STACK(12,nmi_stack_correct, 1)
jmp nmi_stack_correct
nmi_debug_stack_check:
cmpw $__KERNEL_CS,16(%esp)
jne nmi_stack_correct
cmpl $debug,(%esp)
jb nmi_stack_correct
cmpl $debug_esp_fix_insn,(%esp)
ja nmi_stack_correct
FIX_STACK(24,nmi_stack_correct, 1)
jmp nmi_stack_correct
nmi_16bit_stack:
/* create the pointer to lss back */
pushl %ss
pushl %esp
movzwl %sp, %esp
addw $4, (%esp)
/* copy the iret frame of 12 bytes */
.rept 3
pushl 16(%esp)
.endr
pushl %eax
SAVE_ALL
FIXUP_ESPFIX_STACK # %eax == %esp
xorl %edx,%edx # zero error code
call do_nmi
RESTORE_REGS
lss 12+4(%esp), %esp # back to 16bit stack
1: iret
.section __ex_table,"a"
.align 4
.long 1b,iret_exc
.previous
#else
ENTRY(nmi)
pushl %eax
SAVE_ALL
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_nmi
orl $NMI_MASK, EFLAGS(%esp)
jmp restore_all
#endif
KPROBE_ENTRY(int3)
pushl $-1 # mark this as an int
SAVE_ALL
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_int3
jmp ret_from_exception
.previous .text
ENTRY(overflow)
pushl $0
pushl $do_overflow
jmp error_code
ENTRY(bounds)
pushl $0
pushl $do_bounds
jmp error_code
ENTRY(invalid_op)
pushl $0
pushl $do_invalid_op
jmp error_code
ENTRY(coprocessor_segment_overrun)
pushl $0
pushl $do_coprocessor_segment_overrun
jmp error_code
ENTRY(invalid_TSS)
pushl $do_invalid_TSS
jmp error_code
ENTRY(segment_not_present)
pushl $do_segment_not_present
jmp error_code
ENTRY(stack_segment)
pushl $do_stack_segment
jmp error_code
KPROBE_ENTRY(general_protection)
pushl $do_general_protection
jmp error_code
.previous .text
ENTRY(alignment_check)
pushl $do_alignment_check
jmp error_code
KPROBE_ENTRY(page_fault)
pushl $do_page_fault
jmp error_code
.previous .text
#ifdef CONFIG_X86_MCE
ENTRY(machine_check)
pushl $0
pushl machine_check_vector
jmp error_code
#endif
ENTRY(fixup_4gb_segment)
pushl $do_fixup_4gb_segment
jmp error_code
.section .rodata,"a"
#include "syscall_table.S"
syscall_table_size=(.-sys_call_table)
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