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Cleanup i386 entry.S.

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Many of the changes to entry.S can be removed because we don't support
CONFIG_PREEMPT anymore.

Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
This commit is contained in:
cl349@firebug.cl.cam.ac.uk committed 2006-03-07 15:48:36 +00:00
1 parent 5afef2d800
commit 15c0d5d00a
1 file changed
+85 -81
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linux-2.6-xen-sparse/arch/i386/kernel/entry-xen.S
+85 -81
View File
@@ -79,6 +79,10 @@ 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
@@ -86,33 +90,24 @@ NMI_MASK = 0x80000000
#define sizeof_vcpu_shift 6
#ifdef CONFIG_SMP
#define preempt_disable(reg) incl TI_preempt_count(reg)
#define preempt_enable(reg) decl TI_preempt_count(reg)
#define XEN_GET_VCPU_INFO(reg) preempt_disable(%ebp) ; \
movl TI_cpu(%ebp),reg ; \
shl $sizeof_vcpu_shift,reg ; \
addl HYPERVISOR_shared_info,reg
#define XEN_PUT_VCPU_INFO(reg) preempt_enable(%ebp)
#define XEN_PUT_VCPU_INFO_fixup .byte 0xff,0xff,0xff
#define GET_VCPU_INFO movl TI_cpu(%ebp),%esi ; \
shl $sizeof_vcpu_shift,%esi ; \
addl HYPERVISOR_shared_info,%esi
#else
#define XEN_GET_VCPU_INFO(reg) movl HYPERVISOR_shared_info,reg
#define XEN_PUT_VCPU_INFO(reg)
#define XEN_PUT_VCPU_INFO_fixup
#define GET_VCPU_INFO movl HYPERVISOR_shared_info,%esi
#endif
#define XEN_LOCKED_BLOCK_EVENTS(reg) movb $1,evtchn_upcall_mask(reg)
#define XEN_LOCKED_UNBLOCK_EVENTS(reg) movb $0,evtchn_upcall_mask(reg)
#define XEN_BLOCK_EVENTS(reg) XEN_GET_VCPU_INFO(reg) ; \
XEN_LOCKED_BLOCK_EVENTS(reg) ; \
XEN_PUT_VCPU_INFO(reg)
#define XEN_UNBLOCK_EVENTS(reg) XEN_GET_VCPU_INFO(reg) ; \
XEN_LOCKED_UNBLOCK_EVENTS(reg) ; \
XEN_PUT_VCPU_INFO(reg)
#define XEN_TEST_PENDING(reg) testb $0xFF,evtchn_upcall_pending(reg)
#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 GET_THREAD_INFO(%ebp) ; \
XEN_BLOCK_EVENTS(%esi)
#define preempt_stop cli
#else
#define preempt_stop
#define resume_kernel restore_nocheck
@@ -159,21 +154,6 @@ NMI_MASK = 0x80000000
.previous
#define RESTORE_ALL \
RESTORE_REGS \
addl $4, %esp; \
1: iret; \
.section .fixup,"ax"; \
2: pushl $0; \
pushl $do_iret_error; \
jmp error_code; \
.previous; \
.section __ex_table,"a";\
.align 4; \
.long 1b,2b; \
.previous
ENTRY(ret_from_fork)
pushl %eax
call schedule_tail
@@ -199,7 +179,7 @@ ret_from_intr:
testl $(VM_MASK | 2), %eax
jz resume_kernel
ENTRY(resume_userspace)
XEN_BLOCK_EVENTS(%esi) # make sure we don't miss an interrupt
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
@@ -210,15 +190,15 @@ ENTRY(resume_userspace)
#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
XEN_BLOCK_EVENTS(%esi)
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
testb $0xFF,EVENT_MASK(%esp) # interrupts off (exception path) ?
jnz restore_all
testl $IF_MASK,EFLAGS(%esp) # interrupts off (exception path) ?
jz restore_all
call preempt_schedule_irq
jmp need_resched
#endif
@@ -289,7 +269,7 @@ syscall_call:
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp) # store the return value
syscall_exit:
XEN_BLOCK_EVENTS(%esi) # make sure we don't miss an interrupt
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
@@ -297,7 +277,7 @@ syscall_exit:
jne syscall_exit_work
restore_all:
#if 0 /* XEN */
#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.
@@ -307,22 +287,26 @@ restore_all:
andl $(VM_MASK | (4 << 8) | 3), %eax
cmpl $((4 << 8) | 3), %eax
je ldt_ss # returning to user-space with LDT SS
#endif /* XEN */
restore_nocheck:
#else
restore_nocheck:
testl $(VM_MASK|NMI_MASK), EFLAGS(%esp)
jnz hypervisor_iret
movb EVENT_MASK(%esp), %al
notb %al # %al == ~saved_mask
XEN_GET_VCPU_INFO(%esi)
GET_VCPU_INFO
andb evtchn_upcall_mask(%esi),%al
andb $1,%al # %al == mask & ~saved_mask
jnz restore_all_enable_events # != 0 => reenable event delivery
XEN_PUT_VCPU_INFO(%esi)
#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
@@ -332,13 +316,7 @@ iret_exc:
.long 1b,iret_exc
.previous
hypervisor_iret:
andl $~NMI_MASK, EFLAGS(%esp)
RESTORE_REGS
addl $4, %esp
jmp hypercall_page + (__HYPERVISOR_iret * 32)
#if 0 /* XEN */
#ifndef CONFIG_XEN
ldt_ss:
larl OLDSS(%esp), %eax
jnz restore_nocheck
@@ -363,7 +341,13 @@ ldt_ss:
.align 4
.long 1b,iret_exc
.previous
#endif /* XEN */
#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
@@ -372,7 +356,7 @@ work_pending:
jz work_notifysig
work_resched:
call schedule
XEN_BLOCK_EVENTS(%esi) # make sure we don't miss an interrupt
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
@@ -424,7 +408,7 @@ syscall_trace_entry:
syscall_exit_work:
testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
jz work_pending
XEN_UNBLOCK_EVENTS(%esi) # could let do_syscall_trace() call
ENABLE_INTERRUPTS # could let do_syscall_trace() call
# schedule() instead
movl %esp, %eax
movl $1, %edx
@@ -444,7 +428,7 @@ syscall_badsys:
movl $-ENOSYS,EAX(%esp)
jmp resume_userspace
#if 0 /* XEN */
#ifndef CONFIG_XEN
#define FIXUP_ESPFIX_STACK \
movl %esp, %eax; \
/* switch to 32bit stack using the pointer on top of 16bit stack */ \
@@ -503,7 +487,9 @@ ENTRY(name) \
/* The include is where all of the SMP etc. interrupts come from */
#include "entry_arch.h"
#endif /* XEN */
#else
#define UNWIND_ESPFIX_STACK
#endif
ENTRY(divide_error)
pushl $0 # no error code
@@ -522,7 +508,7 @@ error_code:
pushl %ebx
cld
pushl %es
# UNWIND_ESPFIX_STACK
UNWIND_ESPFIX_STACK
popl %ecx
movl ES(%esp), %edi # get the function address
movl ORIG_EAX(%esp), %edx # get the error code
@@ -535,6 +521,7 @@ error_code:
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
@@ -561,14 +548,23 @@ ENTRY(hypervisor_callback)
ALIGN
restore_all_enable_events:
XEN_LOCKED_UNBLOCK_EVENTS(%esi)
__ENABLE_INTERRUPTS
scrit: /**** START OF CRITICAL REGION ****/
XEN_TEST_PENDING(%esi)
__TEST_PENDING
jnz 14f # process more events if necessary...
XEN_PUT_VCPU_INFO(%esi)
RESTORE_ALL
14: XEN_LOCKED_BLOCK_EVENTS(%esi)
XEN_PUT_VCPU_INFO(%esi)
RESTORE_REGS
addl $4, %esp
1: iret
.section .fixup,"ax"
2: pushl $0
pushl $do_iret_error
jmp error_code
.previous
.section __ex_table,"a"
.align 4
.long 1b,2b
.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
@@ -584,7 +580,6 @@ critical_region_fixup:
cmpb $0xff,%al # 0xff => vcpu_info critical region
jne 15f
GET_THREAD_INFO(%ebp)
XEN_PUT_VCPU_INFO(%esi) # abort vcpu_info critical region
xorl %eax,%eax
15: mov %esp,%esi
add %eax,%esi # %esi points at end of src region
@@ -602,9 +597,8 @@ critical_region_fixup:
jmp 11b
critical_fixup_table:
.byte 0xff,0xff,0xff # testb $0xff,(%esi) = XEN_TEST_PENDING
.byte 0xff,0xff,0xff # testb $0xff,(%esi) = __TEST_PENDING
.byte 0xff,0xff # jnz 14f
XEN_PUT_VCPU_INFO_fixup
.byte 0x00 # pop %ebx
.byte 0x04 # pop %ecx
.byte 0x08 # pop %edx
@@ -617,7 +611,6 @@ critical_fixup_table:
.byte 0x24,0x24,0x24 # add $4,%esp
.byte 0x28 # iret
.byte 0xff,0xff,0xff,0xff # movb $1,1(%esi)
XEN_PUT_VCPU_INFO_fixup
.byte 0x00,0x00 # jmp 11b
# Hypervisor uses this for application faults while it executes.
@@ -646,6 +639,7 @@ ENTRY(failsafe_callback)
.long 3b,8b; \
.long 4b,9b; \
.previous
#endif
ENTRY(coprocessor_error)
pushl $0
@@ -660,7 +654,17 @@ ENTRY(simd_coprocessor_error)
ENTRY(device_not_available)
pushl $-1 # mark this as an int
SAVE_ALL
#preempt_stop /* This is already an interrupt gate on Xen. */
#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
@@ -703,16 +707,7 @@ debug_stack_correct:
jmp ret_from_exception
.previous .text
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
#if 0 /* XEN */
#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
@@ -783,7 +778,16 @@ nmi_16bit_stack:
.align 4
.long 1b,iret_exc
.previous
#endif /* XEN */
#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
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