1/** @file 2 Ia32 arch functions to access IDT vector. 3 4 Copyright (c) 2013, Intel Corporation. All rights reserved.<BR> 5 This program and the accompanying materials 6 are licensed and made available under the terms and conditions of the BSD License 7 which accompanies this distribution. The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php. 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13**/ 14 15#include <PeCoffExtraActionLib.h> 16 17/** 18 Read IDT entry to check if IDT entries are setup by Debug Agent. 19 20 @param[in] IdtDescriptor Pointer to IDT Descriptor. 21 @param[in] InterruptType Interrupt type. 22 23 @retval TRUE IDT entries were setup by Debug Agent. 24 @retval FALSE IDT entries were not setuo by Debug Agent. 25 26**/ 27BOOLEAN 28CheckDebugAgentHandler ( 29 IN IA32_DESCRIPTOR *IdtDescriptor, 30 IN UINTN InterruptType 31 ) 32{ 33 IA32_IDT_GATE_DESCRIPTOR *IdtEntry; 34 UINTN InterruptHandler; 35 36 IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base; 37 if (IdtEntry == NULL) { 38 return FALSE; 39 } 40 41 InterruptHandler = IdtEntry[InterruptType].Bits.OffsetLow + 42 (IdtEntry[InterruptType].Bits.OffsetHigh << 16); 43 if (InterruptHandler >= sizeof (UINT32) && *(UINT32 *)(InterruptHandler - sizeof (UINT32)) == AGENT_HANDLER_SIGNATURE) { 44 return TRUE; 45 } else { 46 return FALSE; 47 } 48} 49 50/** 51 Save IDT entry for INT1 and update it. 52 53 @param[in] IdtDescriptor Pointer to IDT Descriptor. 54 @param[out] SavedIdtEntry Original IDT entry returned. 55 56**/ 57VOID 58SaveAndUpdateIdtEntry1 ( 59 IN IA32_DESCRIPTOR *IdtDescriptor, 60 OUT IA32_IDT_GATE_DESCRIPTOR *SavedIdtEntry 61 ) 62{ 63 IA32_IDT_GATE_DESCRIPTOR *IdtEntry; 64 UINT16 CodeSegment; 65 UINTN InterruptHandler; 66 67 IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base; 68 CopyMem (SavedIdtEntry, &IdtEntry[1], sizeof (IA32_IDT_GATE_DESCRIPTOR)); 69 70 // 71 // Use current CS as the segment selector of interrupt gate in IDT 72 // 73 CodeSegment = AsmReadCs (); 74 75 InterruptHandler = (UINTN) &AsmInterruptHandle; 76 IdtEntry[1].Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler; 77 IdtEntry[1].Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16); 78 IdtEntry[1].Bits.Selector = CodeSegment; 79 IdtEntry[1].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32; 80} 81 82/** 83 Restore IDT entry for INT1. 84 85 @param[in] IdtDescriptor Pointer to IDT Descriptor. 86 @param[in] RestoredIdtEntry IDT entry to be restored. 87 88**/ 89VOID 90RestoreIdtEntry1 ( 91 IN IA32_DESCRIPTOR *IdtDescriptor, 92 IN IA32_IDT_GATE_DESCRIPTOR *RestoredIdtEntry 93 ) 94{ 95 IA32_IDT_GATE_DESCRIPTOR *IdtEntry; 96 97 IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base; 98 CopyMem (&IdtEntry[1], RestoredIdtEntry, sizeof (IA32_IDT_GATE_DESCRIPTOR)); 99} 100