当前位置：首页 > news >正文

HalEndSystemInterrupt为什么能调用KiDispatchInterrupt因为HalRequestSoftwareInterrupt设置PCR[PcHal.DpcPending]为1

news 2026/8/13 15:52:18

hal!HalEndSystemInterrupt函数为什么能调用nt!KiDispatchInterrupt函数因为hal!HalRequestSoftwareInterrupt最后设置PCR[PcHal.DpcPending]为1

第一部分：

HeiNewIrql equ [esp + 4]
HeiVector equ [esp + 8]

cPublicProc _HalEndSystemInterrupt ,2
cPublicFpo 2, 0
xor ecx,ecx
mov cl, byte ptr HeiNewIrql ; get new IRQL
mov cl, _HalpIRQLtoTPR[ecx] ; get corresponding TPR value

mov dword ptr APIC[LU_EOI], 0 ; send EOI to APIC local unit
APICFIX edx

cmp cl, DPC_VECTOR ; Is new irql < DPC?
jc short es10 ; Yes, go check for pending DPC

es05: mov dword ptr APIC[LU_TPR], ecx ; Set new Priority

;
; We have to ensure that the requested priority is set before
; we return. The caller is counting on it.
;
mov edx, dword ptr APIC[LU_TPR]
CHECKTPR ecx, edx
stdRET _HalEndSystemInterrupt

es10: cmp PCR[PcHal.DpcPending], 0 ; Is a DPC pending?
mov PCR[PcHal.ShortDpc], 0 ; Clear short dpc flag
jz short es05 ; No, eoi

mov dword ptr APIC[LU_TPR], DPC_VECTOR ; lower to DPC level
APICFIX edx

push ebx ; Save EBX (used by KiDispatchInterrupt)
push ecx ; Save OldIrql
cPublicFpo 2, 2

sti

es20: mov PCR[PcHal.DpcPending], 0 ; Clear pending flag

stdCall _KiDispatchInterrupt ; Dispatch interrupt //这里调用了_KiDispatchInterrupt

cli

pop ecx
pop ebx
jmp short es05

stdENDP _HalEndSystemInterrupt

第二部分：

F:\srv03rtm>grep "DpcPending" -nr F:\srv03rtm\base\hals |grep -v "inary"
F:\srv03rtm\base\hals/halmps/i386/mpswint.asm:132:; DpcPending flag - whomever set ShortDpc will check the flag
F:\srv03rtm\base\hals/halmps/i386/mpswint.asm:136:rsi10: mov PCR[PcHal.DpcPending], 1
F:\srv03rtm\base\hals/halmps/i386/mpsysint.asm:121:es10: cmp PCR[PcHal.DpcPending], 0 ; Is a DPC pending?
F:\srv03rtm\base\hals/halmps/i386/mpsysint.asm:134:es20: mov PCR[PcHal.DpcPending], 0 ; Clear pending flag

参考：

cPublicFastCall HalRequestSoftwareInterrupt ,1
cPublicFpo 0,0

cmp cl, PCR[PcHal.ShortDpc]
je short rsi10

xor eax, eax
mov al, cl ; get irql

;
; In an APIC based system the TPR is the IDTEntry
;

xor ecx, ecx
mov cl, _HalpIRQLtoTPR[eax] ; get IDTEntry for IRQL

;
; Build the ICR Command - Fixed Delivery to Self, IDTEntry == al
;

or ecx, (DELIVER_FIXED OR ICR_SELF)

;
; Make sure the ICR is available
;

pushfd ; save interrupt mode
cli ; disable interrupt
STALL_WHILE_APIC_BUSY

;
; Now write the command to the Memory Mapped Register
;

mov dword ptr APIC[LU_INT_CMD_LOW], ecx

;
; We have to wait for the request to be delivered.
; If we don't wait here, then we will return to the caller
; before the request has been issued.
;
STALL_WHILE_APIC_BUSY

popfd ; restore original interrupt mode
fstRET HalRequestSoftwareInterrupt

;
; Requesting a DPC interrupt when ShortDpc is set. Just set the
; DpcPending flag - whomever set ShortDpc will check the flag
; at the proper time
;