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/** @file
X64 specific functions to support Debug Support protocol.
Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "PlDebugSupport.h"
IA32_IDT_GATE_DESCRIPTOR NullDesc = {{0,0}};
/**
Get Interrupt Handle from IDT Gate Descriptor.
@param IdtGateDecriptor IDT Gate Descriptor.
@return Interrupt Handle stored in IDT Gate Descriptor.
**/
UINTN
GetInterruptHandleFromIdt (
IN IA32_IDT_GATE_DESCRIPTOR *IdtGateDecriptor
)
{
UINTN InterruptHandle;
//
// InterruptHandle 0-15 : OffsetLow
// InterruptHandle 16-31 : OffsetHigh
// InterruptHandle 32-63 : OffsetUpper
//
InterruptHandle = ((UINTN) IdtGateDecriptor->Bits.OffsetLow) |
(((UINTN) IdtGateDecriptor->Bits.OffsetHigh) << 16) |
(((UINTN) IdtGateDecriptor->Bits.OffsetUpper) << 32) ;
return InterruptHandle;
}
/**
Allocate pool for a new IDT entry stub.
Copy the generic stub into the new buffer and fixup the vector number
and jump target address.
@param ExceptionType This is the exception type that the new stub will be created
for.
@param Stub On successful exit, *Stub contains the newly allocated entry stub.
**/
VOID
CreateEntryStub (
IN EFI_EXCEPTION_TYPE ExceptionType,
OUT VOID **Stub
)
{
UINT8 *StubCopy;
StubCopy = *Stub;
//
// Fixup the stub code for this vector
//
// The stub code looks like this:
//
// 00000000 6A 00 push 0 ; push vector number - will be modified before installed
// 00000002 E9 db 0e9h ; jump rel32
// 00000003 00000000 dd 0 ; fixed up to relative address of CommonIdtEntry
//
//
// poke in the exception type so the second push pushes the exception type
//
StubCopy[0x1] = (UINT8) ExceptionType;
//
// fixup the jump target to point to the common entry
//
*(UINT32 *) &StubCopy[0x3] = (UINT32)((UINTN) CommonIdtEntry - (UINTN) &StubCopy[StubSize]);
return;
}
/**
This is the main worker function that manages the state of the interrupt
handlers. It both installs and uninstalls interrupt handlers based on the
value of NewCallback. If NewCallback is NULL, then uninstall is indicated.
If NewCallback is non-NULL, then install is indicated.
@param NewCallback If non-NULL, NewCallback specifies the new handler to register.
If NULL, specifies that the previously registered handler should
be uninstalled.
@param ExceptionType Indicates which entry to manage.
@retval EFI_SUCCESS Process is ok.
@retval EFI_INVALID_PARAMETER Requested uninstalling a handler from a vector that has
no handler registered for it
@retval EFI_ALREADY_STARTED Requested install to a vector that already has a handler registered.
@retval others Possible return values are passed through from UnHookEntry and HookEntry.
**/
EFI_STATUS
ManageIdtEntryTable (
CALLBACK_FUNC NewCallback,
EFI_EXCEPTION_TYPE ExceptionType
)
{
EFI_STATUS Status;
Status = EFI_SUCCESS;
if (CompareMem (&IdtEntryTable[ExceptionType].NewDesc, &NullDesc, sizeof (IA32_IDT_GATE_DESCRIPTOR)) != 0) {
//
// we've already installed to this vector
//
if (NewCallback != NULL) {
//
// if the input handler is non-null, error
//
Status = EFI_ALREADY_STARTED;
} else {
UnhookEntry (ExceptionType);
}
} else {
//
// no user handler installed on this vector
//
if (NewCallback == NULL) {
//
// if the input handler is null, error
//
Status = EFI_INVALID_PARAMETER;
} else {
HookEntry (ExceptionType, NewCallback);
}
}
return Status;
}
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