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/** @file
X64 arch function to access IDT vector.
Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <PeCoffExtraActionLib.h>
/**
Read IDT entry to check if IDT entries are setup by Debug Agent.
@param[in] IdtDescriptor Pointer to IDT Descriptor.
@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
)
{
IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
UINTN InterruptHandler;
IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
if (IdtEntry == NULL) {
return FALSE;
}
InterruptHandler = IdtEntry[0].Bits.OffsetLow + (((UINTN)IdtEntry[0].Bits.OffsetHigh) << 16) +
(((UINTN)IdtEntry[0].Bits.OffsetUpper) << 32);
if (InterruptHandler >= 4 && *(UINT32 *)(InterruptHandler - 4) == 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.OffsetUpper = (UINT32)((UINTN)InterruptHandler >> 32);
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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