Source code of Windows XP (NT5)
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/*++
Copyright (c) 1991 Microsoft Corporation
Module Name:
vdmfault.c
Abstract:
This module contains the support for dispatching VDM page faults.
Author:
Sudeep Bharati (sudeepb) 30-Aug-1992
Revision History:
--*/
#include "vdmp.h"
BOOLEAN
VdmDispatchPageFault(
PKTRAP_FRAME TrapFrame,
ULONG Mode,
ULONG FaultAddr
);
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, VdmDispatchPageFault)
#endif
BOOLEAN
VdmDispatchPageFault(
PKTRAP_FRAME TrapFrame,
ULONG Mode,
ULONG FaultAddr
)
/*++
Routine Description:
This routine dispatches a v86 mode page fault to the VDM monitor.
It verifies that the fault occurred below 1MB.
Arguments:
TrapFrame
Mode - 0 - if read
1 - if write
FaultAddr - faulting address
Return Value:
True if successful, False otherwise
--*/
{
PVDM_TIB VdmTib;
NTSTATUS Status;
KIRQL OldIrql;
PAGED_CODE();
Status = VdmpGetVdmTib (&VdmTib);
if (!NT_SUCCESS(Status)) {
return FALSE;
}
KeRaiseIrql(APC_LEVEL, &OldIrql);
//
// VdmTib is in user mode memory
//
if ((TrapFrame->EFlags & EFLAGS_V86_MASK) ||
(TrapFrame->SegCs != (KGDT_R3_CODE | RPL_MASK))) {
//
// If the faulting address is above 1MB return failure.
//
if (FaultAddr < 0x100000) {
try {
VdmTib->EventInfo.Event = VdmMemAccess;
VdmTib->EventInfo.InstructionSize = 0;
VdmTib->EventInfo.FaultInfo.FaultAddr = FaultAddr;
VdmTib->EventInfo.FaultInfo.RWMode = Mode;
VdmEndExecution(TrapFrame, VdmTib);
} except(EXCEPTION_EXECUTE_HANDLER) {
Status = GetExceptionCode();
}
}
else {
Status = STATUS_ILLEGAL_INSTRUCTION;
}
}
KeLowerIrql (OldIrql);
if (!NT_SUCCESS(Status)) {
return FALSE;
}
return TRUE;
}