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linux-next/arch/x86/kernel/entry_32.S
Roland McGrath af0575bba0 i386 syscall audit fast-path 
This adds fast paths for 32-bit syscall entry and exit when
TIF_SYSCALL_AUDIT is set, but no other kind of syscall tracing.
These paths does not need to save and restore all registers as
the general case of tracing does.  Avoiding the iret return path
when syscall audit is enabled helps performance a lot.

Signed-off-by: Roland McGrath <roland@redhat.com>
2008-07-23 18:00:30 -07:00

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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/ftrace.h>
#include <asm/irq_vectors.h>
/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
#include <linux/elf-em.h>
#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
#define __AUDIT_ARCH_LE 0x40000000
#ifndef CONFIG_AUDITSYSCALL
#define sysenter_audit syscall_trace_entry
#define sysexit_audit syscall_exit_work
#endif
/*
* 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_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
jnz sysenter_audit
sysenter_do_call:
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 sysexit_audit
sysenter_exit:
/* 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
#ifdef CONFIG_AUDITSYSCALL
sysenter_audit:
testw $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
jnz syscall_trace_entry
addl $4,%esp
CFI_ADJUST_CFA_OFFSET -4
/* %esi already in 8(%esp) 6th arg: 4th syscall arg */
/* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
/* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
movl %eax,%edx /* 2nd arg: syscall number */
movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
call audit_syscall_entry
pushl %ebx
CFI_ADJUST_CFA_OFFSET 4
movl PT_EAX(%esp),%eax /* reload syscall number */
jmp sysenter_do_call
sysexit_audit:
testw $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %cx
jne syscall_exit_work
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_ANY)
movl %eax,%edx /* second arg, syscall return value */
cmpl $0,%eax /* is it < 0? */
setl %al /* 1 if so, 0 if not */
movzbl %al,%eax /* zero-extend that */
inc %eax /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
call audit_syscall_exit
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
movl TI_flags(%ebp), %ecx
testw $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %cx
jne syscall_exit_work
movl PT_EAX(%esp),%eax /* reload syscall return value */
jmp sysenter_exit
#endif
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_WORK_SYSCALL_ENTRY,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
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
call syscall_trace_enter
/* What it returned is what we'll actually use. */
cmpl $(nr_syscalls), %eax
jnae syscall_call
jmp syscall_exit
END(syscall_trace_entry)
# perform syscall exit tracing
ALIGN
syscall_exit_work:
testb $_TIF_WORK_SYSCALL_EXIT, %cl
jz work_pending
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
# schedule() instead
movl %esp, %eax
call syscall_trace_leave
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 */
CFI_ADJUST_CFA_OFFSET -5*4
jmp sysenter_past_esp
CFI_ENDPROC
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 */
#ifdef CONFIG_FTRACE
#ifdef CONFIG_DYNAMIC_FTRACE
ENTRY(mcount)
pushl %eax
pushl %ecx
pushl %edx
movl 0xc(%esp), %eax
subl $MCOUNT_INSN_SIZE, %eax
.globl mcount_call
mcount_call:
call ftrace_stub
popl %edx
popl %ecx
popl %eax
ret
END(mcount)
ENTRY(ftrace_caller)
pushl %eax
pushl %ecx
pushl %edx
movl 0xc(%esp), %eax
movl 0x4(%ebp), %edx
subl $MCOUNT_INSN_SIZE, %eax
.globl ftrace_call
ftrace_call:
call ftrace_stub
popl %edx
popl %ecx
popl %eax
.globl ftrace_stub
ftrace_stub:
ret
END(ftrace_caller)
#else /* ! CONFIG_DYNAMIC_FTRACE */
ENTRY(mcount)
cmpl $ftrace_stub, ftrace_trace_function
jnz trace
.globl ftrace_stub
ftrace_stub:
ret
/* taken from glibc */
trace:
pushl %eax
pushl %ecx
pushl %edx
movl 0xc(%esp), %eax
movl 0x4(%ebp), %edx
subl $MCOUNT_INSN_SIZE, %eax
call *ftrace_trace_function
popl %edx
popl %ecx
popl %eax
jmp ftrace_stub
END(mcount)
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_FTRACE */
.section .rodata,"a"
#include "syscall_table_32.S"
syscall_table_size=(.-sys_call_table)
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