mirror of https://github.com/acidanthera/audk.git
100 lines
3.0 KiB
C
100 lines
3.0 KiB
C
/** @file
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Ia32 arch functions to access IDT vector.
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Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <PeCoffExtraActionLib.h>
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/**
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Read IDT entry to check if IDT entries are setup by Debug Agent.
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@param[in] IdtDescriptor Pointer to IDT Descriptor.
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@param[in] InterruptType Interrupt type.
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@retval TRUE IDT entries were setup by Debug Agent.
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@retval FALSE IDT entries were not setuo by Debug Agent.
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**/
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BOOLEAN
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CheckDebugAgentHandler (
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IN IA32_DESCRIPTOR *IdtDescriptor,
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IN UINTN InterruptType
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)
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{
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IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
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UINTN InterruptHandler;
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IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
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if (IdtEntry == NULL) {
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return FALSE;
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}
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InterruptHandler = IdtEntry[InterruptType].Bits.OffsetLow +
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(IdtEntry[InterruptType].Bits.OffsetHigh << 16);
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if (InterruptHandler >= sizeof (UINT32) && *(UINT32 *)(InterruptHandler - sizeof (UINT32)) == AGENT_HANDLER_SIGNATURE) {
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return TRUE;
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} else {
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return FALSE;
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}
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}
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/**
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Save IDT entry for INT1 and update it.
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@param[in] IdtDescriptor Pointer to IDT Descriptor.
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@param[out] SavedIdtEntry Original IDT entry returned.
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**/
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VOID
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SaveAndUpdateIdtEntry1 (
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IN IA32_DESCRIPTOR *IdtDescriptor,
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OUT IA32_IDT_GATE_DESCRIPTOR *SavedIdtEntry
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)
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{
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IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
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UINT16 CodeSegment;
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UINTN InterruptHandler;
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IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
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CopyMem (SavedIdtEntry, &IdtEntry[1], sizeof (IA32_IDT_GATE_DESCRIPTOR));
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//
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// Use current CS as the segment selector of interrupt gate in IDT
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//
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CodeSegment = AsmReadCs ();
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InterruptHandler = (UINTN) &AsmInterruptHandle;
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IdtEntry[1].Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
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IdtEntry[1].Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16);
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IdtEntry[1].Bits.Selector = CodeSegment;
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IdtEntry[1].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
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}
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/**
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Restore IDT entry for INT1.
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@param[in] IdtDescriptor Pointer to IDT Descriptor.
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@param[in] RestoredIdtEntry IDT entry to be restored.
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**/
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VOID
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RestoreIdtEntry1 (
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IN IA32_DESCRIPTOR *IdtDescriptor,
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IN IA32_IDT_GATE_DESCRIPTOR *RestoredIdtEntry
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)
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{
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IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
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IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
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CopyMem (&IdtEntry[1], RestoredIdtEntry, sizeof (IA32_IDT_GATE_DESCRIPTOR));
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}
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