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linux/arch/x86/kernel/entry_32.S
Jeremy Fitzhardinge d75cd22fdd x86/paravirt: split sysret and sysexit 
Don't conflate sysret and sysexit; they're different instructions with
different semantics, and may be in use at the same time (at least
within the same kernel, depending on whether its an Intel or AMD
system).

sysexit - just return to userspace, does no register restoration of
    any kind; must explicitly atomically enable interrupts.

sysret - reloads flags from r11, so no need to explicitly enable
    interrupts on 64-bit, responsible for restoring usermode %gs

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citirx.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-08 13:13:15 +02:00

1116 lines
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/*
*
* 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 'syscall_exit':
* 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) - %fs
* 28(%esp) - orig_eax
* 2C(%esp) - %eip
* 30(%esp) - %cs
* 34(%esp) - %eflags
* 38(%esp) - %oldesp
* 3C(%esp) - %oldss
*
* "current" is in register %ebx during any slow entries.
*/
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/irqflags.h>
#include <asm/errno.h>
#include <asm/segment.h>
#include <asm/smp.h>
#include <asm/page.h>
#include <asm/desc.h>
#include <asm/percpu.h>
#include <asm/dwarf2.h>
#include <asm/processor-flags.h>
#include <asm/irq_vectors.h>
/*
* We use macros for low-level operations which need to be overridden
* for paravirtualization. The following will never clobber any registers:
* INTERRUPT_RETURN (aka. "iret")
* GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
* ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
*
* For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
* specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
* Allowing a register to be clobbered can shrink the paravirt replacement
* enough to patch inline, increasing performance.
*/
#define nr_syscalls ((syscall_table_size)/4)
#ifdef CONFIG_PREEMPT
#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
#else
#define preempt_stop(clobbers)
#define resume_kernel restore_nocheck
#endif
.macro TRACE_IRQS_IRET
#ifdef CONFIG_TRACE_IRQFLAGS
testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
jz 1f
TRACE_IRQS_ON
1:
#endif
.endm
#ifdef CONFIG_VM86
#define resume_userspace_sig check_userspace
#else
#define resume_userspace_sig resume_userspace
#endif
#define SAVE_ALL \
cld; \
pushl %fs; \
CFI_ADJUST_CFA_OFFSET 4;\
/*CFI_REL_OFFSET fs, 0;*/\
pushl %es; \
CFI_ADJUST_CFA_OFFSET 4;\
/*CFI_REL_OFFSET es, 0;*/\
pushl %ds; \
CFI_ADJUST_CFA_OFFSET 4;\
/*CFI_REL_OFFSET ds, 0;*/\
pushl %eax; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET eax, 0;\
pushl %ebp; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET ebp, 0;\
pushl %edi; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET edi, 0;\
pushl %esi; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET esi, 0;\
pushl %edx; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET edx, 0;\
pushl %ecx; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET ecx, 0;\
pushl %ebx; \
CFI_ADJUST_CFA_OFFSET 4;\
CFI_REL_OFFSET ebx, 0;\
movl $(__USER_DS), %edx; \
movl %edx, %ds; \
movl %edx, %es; \
movl $(__KERNEL_PERCPU), %edx; \
movl %edx, %fs
#define RESTORE_INT_REGS \
popl %ebx; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE ebx;\
popl %ecx; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE ecx;\
popl %edx; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE edx;\
popl %esi; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE esi;\
popl %edi; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE edi;\
popl %ebp; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE ebp;\
popl %eax; \
CFI_ADJUST_CFA_OFFSET -4;\
CFI_RESTORE eax
#define RESTORE_REGS \
RESTORE_INT_REGS; \
1: popl %ds; \
CFI_ADJUST_CFA_OFFSET -4;\
/*CFI_RESTORE ds;*/\
2: popl %es; \
CFI_ADJUST_CFA_OFFSET -4;\
/*CFI_RESTORE es;*/\
3: popl %fs; \
CFI_ADJUST_CFA_OFFSET -4;\
/*CFI_RESTORE fs;*/\
.pushsection .fixup,"ax"; \
4: movl $0,(%esp); \
jmp 1b; \
5: movl $0,(%esp); \
jmp 2b; \
6: movl $0,(%esp); \
jmp 3b; \
.section __ex_table,"a";\
.align 4; \
.long 1b,4b; \
.long 2b,5b; \
.long 3b,6b; \
.popsection
#define RING0_INT_FRAME \
CFI_STARTPROC simple;\
CFI_SIGNAL_FRAME;\
CFI_DEF_CFA esp, 3*4;\
/*CFI_OFFSET cs, -2*4;*/\
CFI_OFFSET eip, -3*4
#define RING0_EC_FRAME \
CFI_STARTPROC simple;\
CFI_SIGNAL_FRAME;\
CFI_DEF_CFA esp, 4*4;\
/*CFI_OFFSET cs, -2*4;*/\
CFI_OFFSET eip, -3*4
#define RING0_PTREGS_FRAME \
CFI_STARTPROC simple;\
CFI_SIGNAL_FRAME;\
CFI_DEF_CFA esp, PT_OLDESP-PT_EBX;\
/*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/\
CFI_OFFSET eip, PT_EIP-PT_OLDESP;\
/*CFI_OFFSET es, PT_ES-PT_OLDESP;*/\
/*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/\
CFI_OFFSET eax, PT_EAX-PT_OLDESP;\
CFI_OFFSET ebp, PT_EBP-PT_OLDESP;\
CFI_OFFSET edi, PT_EDI-PT_OLDESP;\
CFI_OFFSET esi, PT_ESI-PT_OLDESP;\
CFI_OFFSET edx, PT_EDX-PT_OLDESP;\
CFI_OFFSET ecx, PT_ECX-PT_OLDESP;\
CFI_OFFSET ebx, PT_EBX-PT_OLDESP
ENTRY(ret_from_fork)
CFI_STARTPROC
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
call schedule_tail
GET_THREAD_INFO(%ebp)
popl %eax
CFI_ADJUST_CFA_OFFSET -4
pushl $0x0202 # Reset kernel eflags
CFI_ADJUST_CFA_OFFSET 4
popfl
CFI_ADJUST_CFA_OFFSET -4
jmp syscall_exit
CFI_ENDPROC
END(ret_from_fork)
/*
* 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
RING0_PTREGS_FRAME
ret_from_exception:
preempt_stop(CLBR_ANY)
ret_from_intr:
GET_THREAD_INFO(%ebp)
check_userspace:
movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
movb PT_CS(%esp), %al
andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
cmpl $USER_RPL, %eax
jb resume_kernel # not returning to v8086 or userspace
ENTRY(resume_userspace)
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
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
END(ret_from_exception)
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
DISABLE_INTERRUPTS(CLBR_ANY)
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 $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
jz restore_all
call preempt_schedule_irq
jmp need_resched
END(resume_kernel)
#endif
CFI_ENDPROC
/* 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(ia32_sysenter_target)
CFI_STARTPROC simple
CFI_SIGNAL_FRAME
CFI_DEF_CFA esp, 0
CFI_REGISTER esp, ebp
movl TSS_sysenter_sp0(%esp),%esp
sysenter_past_esp:
/*
* Interrupts are disabled here, but we can't trace it until
* enough kernel state to call TRACE_IRQS_OFF can be called - but
* we immediately enable interrupts at that point anyway.
*/
pushl $(__USER_DS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET ss, 0*/
pushl %ebp
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET esp, 0
pushfl
orl $X86_EFLAGS_IF, (%esp)
CFI_ADJUST_CFA_OFFSET 4
pushl $(__USER_CS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET cs, 0*/
/*
* Push current_thread_info()->sysenter_return to the stack.
* A tiny bit of offset fixup is necessary - 4*4 means the 4 words
* pushed above; +8 corresponds to copy_thread's esp0 setting.
*/
pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET eip, 0
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
ENABLE_INTERRUPTS(CLBR_NONE)
/*
* Load the potential sixth argument from user stack.
* Careful about security.
*/
cmpl $__PAGE_OFFSET-3,%ebp
jae syscall_fault
1: movl (%ebp),%ebp
movl %ebp,PT_EBP(%esp)
.section __ex_table,"a"
.align 4
.long 1b,syscall_fault
.previous
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,PT_EAX(%esp)
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx
jne syscall_exit_work
/* if something modifies registers it must also disable sysexit */
movl PT_EIP(%esp), %edx
movl PT_OLDESP(%esp), %ecx
xorl %ebp,%ebp
TRACE_IRQS_ON
1: mov PT_FS(%esp), %fs
ENABLE_INTERRUPTS_SYSEXIT
CFI_ENDPROC
.pushsection .fixup,"ax"
2: movl $0,PT_FS(%esp)
jmp 1b
.section __ex_table,"a"
.align 4
.long 1b,2b
.popsection
ENDPROC(ia32_sysenter_target)
# system call handler stub
ENTRY(system_call)
RING0_INT_FRAME # can't unwind into user space anyway
pushl %eax # save orig_eax
CFI_ADJUST_CFA_OFFSET 4
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,PT_EAX(%esp) # store the return value
syscall_exit:
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
testl $X86_EFLAGS_TF,PT_EFLAGS(%esp) # If tracing set singlestep flag on exit
jz no_singlestep
orl $_TIF_SINGLESTEP,TI_flags(%ebp)
no_singlestep:
movl TI_flags(%ebp), %ecx
testw $_TIF_ALLWORK_MASK, %cx # current->work
jne syscall_exit_work
restore_all:
movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
# Warning: PT_OLDSS(%esp) contains the wrong/random values if we
# are returning to the kernel.
# See comments in process.c:copy_thread() for details.
movb PT_OLDSS(%esp), %ah
movb PT_CS(%esp), %al
andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
CFI_REMEMBER_STATE
je ldt_ss # returning to user-space with LDT SS
restore_nocheck:
TRACE_IRQS_IRET
restore_nocheck_notrace:
RESTORE_REGS
addl $4, %esp # skip orig_eax/error_code
CFI_ADJUST_CFA_OFFSET -4
irq_return:
INTERRUPT_RETURN
.section .fixup,"ax"
ENTRY(iret_exc)
pushl $0 # no error code
pushl $do_iret_error
jmp error_code
.previous
.section __ex_table,"a"
.align 4
.long irq_return,iret_exc
.previous
CFI_RESTORE_STATE
ldt_ss:
larl PT_OLDSS(%esp), %eax
jnz restore_nocheck
testl $0x00400000, %eax # returning to 32bit stack?
jnz restore_nocheck # allright, normal return
#ifdef CONFIG_PARAVIRT
/*
* The kernel can't run on a non-flat stack if paravirt mode
* is active. Rather than try to fixup the high bits of
* ESP, bypass this code entirely. This may break DOSemu
* and/or Wine support in a paravirt VM, although the option
* is still available to implement the setting of the high
* 16-bits in the INTERRUPT_RETURN paravirt-op.
*/
cmpl $0, pv_info+PARAVIRT_enabled
jne restore_nocheck
#endif
/* 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. */
movl PT_OLDESP(%esp), %eax
movl %esp, %edx
call patch_espfix_desc
pushl $__ESPFIX_SS
CFI_ADJUST_CFA_OFFSET 4
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
DISABLE_INTERRUPTS(CLBR_EAX)
TRACE_IRQS_OFF
lss (%esp), %esp
CFI_ADJUST_CFA_OFFSET -8
jmp restore_nocheck
CFI_ENDPROC
ENDPROC(system_call)
# perform work that needs to be done immediately before resumption
ALIGN
RING0_PTREGS_FRAME # can't unwind into user space anyway
work_pending:
testb $_TIF_NEED_RESCHED, %cl
jz work_notifysig
work_resched:
call schedule
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
TRACE_IRQS_OFF
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
#ifdef CONFIG_VM86
testl $X86_EFLAGS_VM, PT_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_sig
ALIGN
work_notifysig_v86:
pushl %ecx # save ti_flags for do_notify_resume
CFI_ADJUST_CFA_OFFSET 4
call save_v86_state # %eax contains pt_regs pointer
popl %ecx
CFI_ADJUST_CFA_OFFSET -4
movl %eax, %esp
#else
movl %esp, %eax
#endif
xorl %edx, %edx
call do_notify_resume
jmp resume_userspace_sig
END(work_pending)
# perform syscall exit tracing
ALIGN
syscall_trace_entry:
movl $-ENOSYS,PT_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 PT_ORIG_EAX(%esp), %eax
cmpl $(nr_syscalls), %eax
jnae syscall_call
jmp syscall_exit
END(syscall_trace_entry)
# perform syscall exit tracing
ALIGN
syscall_exit_work:
testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
jz work_pending
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_ANY) # could let do_syscall_trace() call
# schedule() instead
movl %esp, %eax
movl $1, %edx
call do_syscall_trace
jmp resume_userspace
END(syscall_exit_work)
CFI_ENDPROC
RING0_INT_FRAME # can't unwind into user space anyway
syscall_fault:
GET_THREAD_INFO(%ebp)
movl $-EFAULT,PT_EAX(%esp)
jmp resume_userspace
END(syscall_fault)
syscall_badsys:
movl $-ENOSYS,PT_EAX(%esp)
jmp resume_userspace
END(syscall_badsys)
CFI_ENDPROC
#define FIXUP_ESPFIX_STACK \
/* since we are on a wrong stack, we cant make it a C code :( */ \
PER_CPU(gdt_page, %ebx); \
GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
addl %esp, %eax; \
pushl $__KERNEL_DS; \
CFI_ADJUST_CFA_OFFSET 4; \
pushl %eax; \
CFI_ADJUST_CFA_OFFSET 4; \
lss (%esp), %esp; \
CFI_ADJUST_CFA_OFFSET -8;
#define UNWIND_ESPFIX_STACK \
movl %ss, %eax; \
/* see if on espfix stack */ \
cmpw $__ESPFIX_SS, %ax; \
jne 27f; \
movl $__KERNEL_DS, %eax; \
movl %eax, %ds; \
movl %eax, %es; \
/* switch to normal stack */ \
FIXUP_ESPFIX_STACK; \
27:;
/*
* Build the entry stubs and pointer table with
* some assembler magic.
*/
.section .rodata,"a"
ENTRY(interrupt)
.text
ENTRY(irq_entries_start)
RING0_INT_FRAME
vector=0
.rept NR_IRQS
ALIGN
.if vector
CFI_ADJUST_CFA_OFFSET -4
.endif
1: pushl $~(vector)
CFI_ADJUST_CFA_OFFSET 4
jmp common_interrupt
.previous
.long 1b
.text
vector=vector+1
.endr
END(irq_entries_start)
.previous
END(interrupt)
.previous
/*
* the CPU automatically disables interrupts when executing an IRQ vector,
* so IRQ-flags tracing has to follow that:
*/
ALIGN
common_interrupt:
SAVE_ALL
TRACE_IRQS_OFF
movl %esp,%eax
call do_IRQ
jmp ret_from_intr
ENDPROC(common_interrupt)
CFI_ENDPROC
#define BUILD_INTERRUPT(name, nr) \
ENTRY(name) \
RING0_INT_FRAME; \
pushl $~(nr); \
CFI_ADJUST_CFA_OFFSET 4; \
SAVE_ALL; \
TRACE_IRQS_OFF \
movl %esp,%eax; \
call smp_##name; \
jmp ret_from_intr; \
CFI_ENDPROC; \
ENDPROC(name)
/* The include is where all of the SMP etc. interrupts come from */
#include "entry_arch.h"
KPROBE_ENTRY(page_fault)
RING0_EC_FRAME
pushl $do_page_fault
CFI_ADJUST_CFA_OFFSET 4
ALIGN
error_code:
/* the function address is in %fs's slot on the stack */
pushl %es
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET es, 0*/
pushl %ds
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET ds, 0*/
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET eax, 0
pushl %ebp
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ebp, 0
pushl %edi
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edi, 0
pushl %esi
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET esi, 0
pushl %edx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET edx, 0
pushl %ecx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ecx, 0
pushl %ebx
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET ebx, 0
cld
pushl %fs
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET fs, 0*/
movl $(__KERNEL_PERCPU), %ecx
movl %ecx, %fs
UNWIND_ESPFIX_STACK
popl %ecx
CFI_ADJUST_CFA_OFFSET -4
/*CFI_REGISTER es, ecx*/
movl PT_FS(%esp), %edi # get the function address
movl PT_ORIG_EAX(%esp), %edx # get the error code
movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
mov %ecx, PT_FS(%esp)
/*CFI_REL_OFFSET fs, ES*/
movl $(__USER_DS), %ecx
movl %ecx, %ds
movl %ecx, %es
movl %esp,%eax # pt_regs pointer
call *%edi
jmp ret_from_exception
CFI_ENDPROC
KPROBE_END(page_fault)
ENTRY(coprocessor_error)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_coprocessor_error
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(coprocessor_error)
ENTRY(simd_coprocessor_error)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_simd_coprocessor_error
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(simd_coprocessor_error)
ENTRY(device_not_available)
RING0_INT_FRAME
pushl $-1 # mark this as an int
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
GET_CR0_INTO_EAX
testl $0x4, %eax # EM (math emulation bit)
jne device_not_available_emulate
preempt_stop(CLBR_ANY)
call math_state_restore
jmp ret_from_exception
device_not_available_emulate:
pushl $0 # temporary storage for ORIG_EIP
CFI_ADJUST_CFA_OFFSET 4
call math_emulate
addl $4, %esp
CFI_ADJUST_CFA_OFFSET -4
jmp ret_from_exception
CFI_ENDPROC
END(device_not_available)
/*
* 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.
*
* "TSS_sysenter_sp0+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 TSS_sysenter_sp0+offset(%esp),%esp; \
CFI_DEF_CFA esp, 0; \
CFI_UNDEFINED eip; \
pushfl; \
CFI_ADJUST_CFA_OFFSET 4; \
pushl $__KERNEL_CS; \
CFI_ADJUST_CFA_OFFSET 4; \
pushl $sysenter_past_esp; \
CFI_ADJUST_CFA_OFFSET 4; \
CFI_REL_OFFSET eip, 0
KPROBE_ENTRY(debug)
RING0_INT_FRAME
cmpl $ia32_sysenter_target,(%esp)
jne debug_stack_correct
FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
debug_stack_correct:
pushl $-1 # mark this as an int
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
xorl %edx,%edx # error code 0
movl %esp,%eax # pt_regs pointer
call do_debug
jmp ret_from_exception
CFI_ENDPROC
KPROBE_END(debug)
/*
* 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.
*/
KPROBE_ENTRY(nmi)
RING0_INT_FRAME
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
movl %ss, %eax
cmpw $__ESPFIX_SS, %ax
popl %eax
CFI_ADJUST_CFA_OFFSET -4
je nmi_espfix_stack
cmpl $ia32_sysenter_target,(%esp)
je nmi_stack_fixup
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
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
CFI_ADJUST_CFA_OFFSET -4
jae nmi_stack_correct
cmpl $ia32_sysenter_target,12(%esp)
je nmi_debug_stack_check
nmi_stack_correct:
/* We have a RING0_INT_FRAME here */
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_nmi
jmp restore_nocheck_notrace
CFI_ENDPROC
nmi_stack_fixup:
RING0_INT_FRAME
FIX_STACK(12,nmi_stack_correct, 1)
jmp nmi_stack_correct
nmi_debug_stack_check:
/* We have a RING0_INT_FRAME here */
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_espfix_stack:
/* We have a RING0_INT_FRAME here.
*
* create the pointer to lss back
*/
pushl %ss
CFI_ADJUST_CFA_OFFSET 4
pushl %esp
CFI_ADJUST_CFA_OFFSET 4
addw $4, (%esp)
/* copy the iret frame of 12 bytes */
.rept 3
pushl 16(%esp)
CFI_ADJUST_CFA_OFFSET 4
.endr
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
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 espfix stack
CFI_ADJUST_CFA_OFFSET -24
jmp irq_return
CFI_ENDPROC
KPROBE_END(nmi)
#ifdef CONFIG_PARAVIRT
ENTRY(native_iret)
iret
.section __ex_table,"a"
.align 4
.long native_iret, iret_exc
.previous
END(native_iret)
ENTRY(native_irq_enable_sysexit)
sti
sysexit
END(native_irq_enable_sysexit)
#endif
KPROBE_ENTRY(int3)
RING0_INT_FRAME
pushl $-1 # mark this as an int
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
xorl %edx,%edx # zero error code
movl %esp,%eax # pt_regs pointer
call do_int3
jmp ret_from_exception
CFI_ENDPROC
KPROBE_END(int3)
ENTRY(overflow)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_overflow
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(overflow)
ENTRY(bounds)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_bounds
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(bounds)
ENTRY(invalid_op)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_invalid_op
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(invalid_op)
ENTRY(coprocessor_segment_overrun)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_coprocessor_segment_overrun
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(coprocessor_segment_overrun)
ENTRY(invalid_TSS)
RING0_EC_FRAME
pushl $do_invalid_TSS
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(invalid_TSS)
ENTRY(segment_not_present)
RING0_EC_FRAME
pushl $do_segment_not_present
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(segment_not_present)
ENTRY(stack_segment)
RING0_EC_FRAME
pushl $do_stack_segment
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(stack_segment)
KPROBE_ENTRY(general_protection)
RING0_EC_FRAME
pushl $do_general_protection
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
KPROBE_END(general_protection)
ENTRY(alignment_check)
RING0_EC_FRAME
pushl $do_alignment_check
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(alignment_check)
ENTRY(divide_error)
RING0_INT_FRAME
pushl $0 # no error code
CFI_ADJUST_CFA_OFFSET 4
pushl $do_divide_error
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(divide_error)
#ifdef CONFIG_X86_MCE
ENTRY(machine_check)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl machine_check_vector
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(machine_check)
#endif
ENTRY(spurious_interrupt_bug)
RING0_INT_FRAME
pushl $0
CFI_ADJUST_CFA_OFFSET 4
pushl $do_spurious_interrupt_bug
CFI_ADJUST_CFA_OFFSET 4
jmp error_code
CFI_ENDPROC
END(spurious_interrupt_bug)
ENTRY(kernel_thread_helper)
pushl $0 # fake return address for unwinder
CFI_STARTPROC
movl %edx,%eax
push %edx
CFI_ADJUST_CFA_OFFSET 4
call *%ebx
push %eax
CFI_ADJUST_CFA_OFFSET 4
call do_exit
CFI_ENDPROC
ENDPROC(kernel_thread_helper)
#ifdef CONFIG_XEN
/* Xen doesn't set %esp to be precisely what the normal sysenter
entrypoint expects, so fix it up before using the normal path. */
ENTRY(xen_sysenter_target)
RING0_INT_FRAME
addl $5*4, %esp /* remove xen-provided frame */
jmp sysenter_past_esp
ENTRY(xen_hypervisor_callback)
CFI_STARTPROC
pushl $0
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
TRACE_IRQS_OFF
/* Check to see if we got the event in the critical
region in xen_iret_direct, after we've reenabled
events and checked for pending events. This simulates
iret instruction's behaviour where it delivers a
pending interrupt when enabling interrupts. */
movl PT_EIP(%esp),%eax
cmpl $xen_iret_start_crit,%eax
jb 1f
cmpl $xen_iret_end_crit,%eax
jae 1f
jmp xen_iret_crit_fixup
ENTRY(xen_do_upcall)
1: mov %esp, %eax
call xen_evtchn_do_upcall
jmp ret_from_intr
CFI_ENDPROC
ENDPROC(xen_hypervisor_callback)
# 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(xen_failsafe_callback)
CFI_STARTPROC
pushl %eax
CFI_ADJUST_CFA_OFFSET 4
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
CFI_ADJUST_CFA_OFFSET -4
lea 16(%esp),%esp
CFI_ADJUST_CFA_OFFSET -16
jz 5f
addl $16,%esp
jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
5: pushl $0 # EAX == 0 => Category 1 (Bad segment)
CFI_ADJUST_CFA_OFFSET 4
SAVE_ALL
jmp ret_from_exception
CFI_ENDPROC
.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
ENDPROC(xen_failsafe_callback)
#endif /* CONFIG_XEN */
.section .rodata,"a"
#include "syscall_table_32.S"
syscall_table_size=(.-sys_call_table)
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