Source code of Windows XP (NT5)
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165 lines
3.6 KiB

if NT_INST
else
TITLE "Spin Locks"
;++
;
; Copyright (c) 1989 Microsoft Corporation
;
; Module Name:
;
; spindbg.asm
;
; Abstract:
;
; Author:
;
; Bryan Willman (bryanwi) 13 Dec 89
;
; Environment:
;
; Kernel mode only.
;
; Revision History:
;
;--
PAGE
.386p
include ks386.inc
include callconv.inc ; calling convention macros
include mac386.inc
if DBG
EXTRNP _KeBugCheckEx,5
EXTRNP _KeGetCurrentIrql,0,IMPORT
ifdef DBGMP
EXTRNP _KiPollDebugger,0
endif
extrn _KeTickCount:DWORD
extrn _KiSpinlockTimeout:DWORD
endif
_TEXT$00 SEGMENT DWORD PUBLIC 'CODE'
ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING
;++
;
; VOID
; Kii386SpinOnSpinLock (
; IN PKSPIN_LOCK SpinLock
; IN ULONG Flag
; )
;
; Routine Description:
;
; This function is called on a debug build to spin on a spinlock.
; It is invoked by the DEBUG version of SPIN_ON_SPINLOCK macro.
;
; Warning:
;
; Not called with C calling conventions
; Does not destroy any register
;
;--
cPublicProc Kii386SpinOnSpinLock,2
if DBG
cPublicFpo 2,2
push eax
push ebx
mov eax, [esp+12] ; (eax) = LockAddress
mov ebx, PCR[PcPrcbData.PbCurrentThread]
or ebx, 1 ; or on busy bit
cmp ebx, [eax] ; current thread the owner?
je short ssl_sameid ; Yes, go abort
ssl_10:
mov ebx, _KeTickCount ; Current time
add ebx, _KiSpinlockTimeout ; wait n ticks
ifdef DBGMP
test byte ptr [esp+16], 2 ; poll debugger while waiting?
jnz short ssl_30
endif
;
; Spin while watching KeTickCount
;
ssl_20: YIELD
cmp _KeTickCount, ebx ; check current time
jnc short ssl_timeout ; NC, too many ticks have gone by
test dword ptr [eax], 1
jnz short ssl_20
ssl_exit:
pop ebx ; Spinlock is not busy, return
pop eax
stdRET Kii386SpinOnSpinLock
ifdef DBGMP
;
; Spin while watching KeTickCount & poll debugger
;
ssl_30: YIELD
cmp _KeTickCount, ebx ; check current time
jnc short ssl_timeout ; overflowed
stdCall _KiPollDebugger
test dword ptr [eax], 1
jnz short ssl_30
pop ebx ; Spinlock is not busy, return
pop eax
stdRET Kii386SpinOnSpinLock
endif
;
; Out of line expection conditions
;
ssl_sameid:
test byte ptr [esp+16], 1 ; ID check enabled?
jz short ssl_10 ; no, continue
; recursed on lock, abort
stdCall _KeBugCheckEx,<SPIN_LOCK_ALREADY_OWNED,eax,0,0,0>
ssl_timeout:
test byte ptr [esp+16], 4 ; Timeout check enabled?
jz short ssl_10 ; no, continue
stdCall _KeGetCurrentIrql ; Check to see what level we're spinning at
cmp al, DISPATCH_LEVEL
mov eax, [esp+12] ; restore eax
jc short ssl_10 ; if < dispatch_level, don't timeout
test dword ptr [eax], 1 ; Check to see if spinlock was freed
jz short ssl_exit
public SpinLockSpinningForTooLong
SpinLockSpinningForTooLong:
int 3 ; Stop here
jmp short ssl_10 ; re-wait
else ; DBG
stdRET Kii386SpinOnSpinLock
endif
stdENDP Kii386SpinOnSpinLock,2
_TEXT$00 ends
endif ; NT_INST
end