1 /** @file
2 X64 arch function 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 **/
27 BOOLEAN
CheckDebugAgentHandler(IN IA32_DESCRIPTOR * IdtDescriptor,IN UINTN InterruptType)28 CheckDebugAgentHandler (
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 (((UINTN)IdtEntry[InterruptType].Bits.OffsetHigh) << 16) +
43 (((UINTN)IdtEntry[InterruptType].Bits.OffsetUpper) << 32);
44 if (InterruptHandler >= sizeof (UINT32) && *(UINT32 *)(InterruptHandler - sizeof (UINT32)) == AGENT_HANDLER_SIGNATURE) {
45 return TRUE;
46 } else {
47 return FALSE;
48 }
49 }
50
51 /**
52 Save IDT entry for INT1 and update it.
53
54 @param[in] IdtDescriptor Pointer to IDT Descriptor.
55 @param[out] SavedIdtEntry Original IDT entry returned.
56
57 **/
58 VOID
SaveAndUpdateIdtEntry1(IN IA32_DESCRIPTOR * IdtDescriptor,OUT IA32_IDT_GATE_DESCRIPTOR * SavedIdtEntry)59 SaveAndUpdateIdtEntry1 (
60 IN IA32_DESCRIPTOR *IdtDescriptor,
61 OUT IA32_IDT_GATE_DESCRIPTOR *SavedIdtEntry
62 )
63 {
64 IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
65 UINT16 CodeSegment;
66 UINTN InterruptHandler;
67
68 IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
69 CopyMem (SavedIdtEntry, &IdtEntry[1], sizeof (IA32_IDT_GATE_DESCRIPTOR));
70
71 //
72 // Use current CS as the segment selector of interrupt gate in IDT
73 //
74 CodeSegment = AsmReadCs ();
75
76 InterruptHandler = (UINTN) &AsmInterruptHandle;
77 IdtEntry[1].Bits.OffsetLow = (UINT16)(UINTN)InterruptHandler;
78 IdtEntry[1].Bits.OffsetHigh = (UINT16)((UINTN)InterruptHandler >> 16);
79 IdtEntry[1].Bits.OffsetUpper = (UINT32)((UINTN)InterruptHandler >> 32);
80 IdtEntry[1].Bits.Selector = CodeSegment;
81 IdtEntry[1].Bits.GateType = IA32_IDT_GATE_TYPE_INTERRUPT_32;
82 }
83
84 /**
85 Restore IDT entry for INT1.
86
87 @param[in] IdtDescriptor Pointer to IDT Descriptor.
88 @param[in] RestoredIdtEntry IDT entry to be restored.
89
90 **/
91 VOID
RestoreIdtEntry1(IN IA32_DESCRIPTOR * IdtDescriptor,IN IA32_IDT_GATE_DESCRIPTOR * RestoredIdtEntry)92 RestoreIdtEntry1 (
93 IN IA32_DESCRIPTOR *IdtDescriptor,
94 IN IA32_IDT_GATE_DESCRIPTOR *RestoredIdtEntry
95 )
96 {
97 IA32_IDT_GATE_DESCRIPTOR *IdtEntry;
98
99 IdtEntry = (IA32_IDT_GATE_DESCRIPTOR *) IdtDescriptor->Base;
100 CopyMem (&IdtEntry[1], RestoredIdtEntry, sizeof (IA32_IDT_GATE_DESCRIPTOR));
101 }
102