2 IA32 specific functions to support Debug Support protocol.
4 Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
5 SPDX-License-Identifier: BSD-2-Clause-Patent
9 #include "PlDebugSupport.h"
11 IA32_IDT_GATE_DESCRIPTOR NullDesc
= {
16 Get Interrupt Handle from IDT Gate Descriptor.
18 @param IdtGateDescriptor IDT Gate Descriptor.
20 @return Interrupt Handle stored in IDT Gate Descriptor.
24 GetInterruptHandleFromIdt (
25 IN IA32_IDT_GATE_DESCRIPTOR
*IdtGateDescriptor
28 UINTN InterruptHandle
;
31 // InterruptHandle 0-15 : OffsetLow
32 // InterruptHandle 16-31 : OffsetHigh
34 ((UINT16
*)&InterruptHandle
)[0] = (UINT16
)IdtGateDescriptor
->Bits
.OffsetLow
;
35 ((UINT16
*)&InterruptHandle
)[1] = (UINT16
)IdtGateDescriptor
->Bits
.OffsetHigh
;
37 return InterruptHandle
;
41 Allocate pool for a new IDT entry stub.
43 Copy the generic stub into the new buffer and fixup the vector number
44 and jump target address.
46 @param ExceptionType This is the exception type that the new stub will be created
48 @param Stub On successful exit, *Stub contains the newly allocated entry stub.
53 IN EFI_EXCEPTION_TYPE ExceptionType
,
62 // Fixup the stub code for this vector
65 // The stub code looks like this:
67 // 00000000 89 25 00000004 R mov AppEsp, esp ; save stack top
68 // 00000006 BC 00008014 R mov esp, offset DbgStkBot ; switch to debugger stack
69 // 0000000B 6A 00 push 0 ; push vector number - will be modified before installed
70 // 0000000D E9 db 0e9h ; jump rel32
71 // 0000000E 00000000 dd 0 ; fixed up to relative address of CommonIdtEntry
75 // poke in the exception type so the second push pushes the exception type
77 StubCopy
[0x0c] = (UINT8
)ExceptionType
;
80 // fixup the jump target to point to the common entry
82 *(UINT32
*)&StubCopy
[0x0e] = (UINT32
)CommonIdtEntry
- (UINT32
)&StubCopy
[StubSize
];
88 This is the main worker function that manages the state of the interrupt
89 handlers. It both installs and uninstalls interrupt handlers based on the
90 value of NewCallback. If NewCallback is NULL, then uninstall is indicated.
91 If NewCallback is non-NULL, then install is indicated.
93 @param NewCallback If non-NULL, NewCallback specifies the new handler to register.
94 If NULL, specifies that the previously registered handler should
96 @param ExceptionType Indicates which entry to manage.
98 @retval EFI_SUCCESS Installing or Uninstalling operation is ok.
99 @retval EFI_INVALID_PARAMETER Requested uninstalling a handler from a vector that has
100 no handler registered for it
101 @retval EFI_ALREADY_STARTED Requested install to a vector that already has a handler registered.
105 ManageIdtEntryTable (
106 CALLBACK_FUNC NewCallback
,
107 EFI_EXCEPTION_TYPE ExceptionType
112 Status
= EFI_SUCCESS
;
114 if (CompareMem (&IdtEntryTable
[ExceptionType
].NewDesc
, &NullDesc
, sizeof (IA32_IDT_GATE_DESCRIPTOR
)) != 0) {
116 // we've already installed to this vector
118 if (NewCallback
!= NULL
) {
120 // if the input handler is non-null, error
122 Status
= EFI_ALREADY_STARTED
;
124 UnhookEntry (ExceptionType
);
128 // no user handler installed on this vector
130 if (NewCallback
== NULL
) {
132 // if the input handler is null, error
134 Status
= EFI_INVALID_PARAMETER
;
136 HookEntry (ExceptionType
, NewCallback
);