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/** @file
Ia32 arch functions to access IDT vector.
Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PeCoffExtraActionLib.h>
/**
Read IDT entry to check if IDT entries are setup by Debug Agent.
@param[in] IdtDescriptor Pointer to IDT Descriptor.
@param[in] InterruptType Interrupt type.
@retval TRUE IDT entries were setup by Debug Agent.
@retval FALSE IDT entries were not setuo by Debug Agent.
**/
BOOLEAN
CheckDebugAgentHandler (
IN IA32_DESCRIPTOR *IdtDescriptor,
IN UINTN InterruptType
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
UINTN InterruptHandler;
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
if (IdtEntry == NULL) {
return FALSE;
}
InterruptHandler = IdtEntry[InterruptType].Bits.OffsetLow +
(IdtEntry[InterruptType].Bits.OffsetHigh << 16);
if (InterruptHandler >= sizeof (UINT32) && *(UINT32 *)(InterruptHandler - sizeof (UINT32)) == AGENT_HANDLER_SIGNATURE) {
return TRUE;
} else {
return FALSE;
}
}
/**
Save IDT entry for INT1 and update it.
@param[in] IdtDescriptor Pointer to IDT Descriptor.
@param[out] SavedIdtEntry Original IDT entry returned.
**/
VOID
SaveAndUpdateIdtEntry1 (
IN IA32_DESCRIPTOR *IdtDescriptor,
OUT IA32_IDT_GATE_DESCRIPTOR *SavedIdtEntry
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
UINT16 CodeSegment;
UINTN InterruptHandler;
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
CopyMem (SavedIdtEntry, &IdtEntry[1], sizeof (IA32_IDT_GATE_DESCRIPTOR));
//
// Use current CS as the segment selector of interrupt gate in IDT
//
CodeSegment = AsmReadCs ();
InterruptHandler = (UINTN) &AsmInterruptHandle;
IdtEntry[1].Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
IdtEntry[1].Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16);
IdtEntry[1].Bits.Selector = CodeSegment;
IdtEntry[1].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
}
/**
Restore IDT entry for INT1.
@param[in] IdtDescriptor Pointer to IDT Descriptor.
@param[in] RestoredIdtEntry IDT entry to be restored.
**/
VOID
RestoreIdtEntry1 (
IN IA32_DESCRIPTOR *IdtDescriptor,
IN IA32_IDT_GATE_DESCRIPTOR *RestoredIdtEntry
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
CopyMem (&IdtEntry[1], RestoredIdtEntry, sizeof (IA32_IDT_GATE_DESCRIPTOR));
}
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