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https://github.com/CloverHackyColor/CloverBootloader.git
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140 lines
4.0 KiB
C
140 lines
4.0 KiB
C
/** @file
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IA32 specific functions to support Debug Support protocol.
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Copyright (c) 2008 - 2010, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include "PlDebugSupport.h"
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IA32_IDT_GATE_DESCRIPTOR NullDesc = {{0}};
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/**
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Get Interrupt Handle from IDT Gate Descriptor.
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@param IdtGateDescriptor IDT Gate Descriptor.
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@return Interrupt Handle stored in IDT Gate Descriptor.
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**/
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UINTN
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GetInterruptHandleFromIdt (
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IN IA32_IDT_GATE_DESCRIPTOR *IdtGateDescriptor
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)
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{
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UINTN InterruptHandle;
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//
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// InterruptHandle 0-15 : OffsetLow
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// InterruptHandle 16-31 : OffsetHigh
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//
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((UINT16 *) &InterruptHandle)[0] = (UINT16) IdtGateDescriptor->Bits.OffsetLow;
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((UINT16 *) &InterruptHandle)[1] = (UINT16) IdtGateDescriptor->Bits.OffsetHigh;
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return InterruptHandle;
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}
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/**
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Allocate pool for a new IDT entry stub.
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Copy the generic stub into the new buffer and fixup the vector number
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and jump target address.
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@param ExceptionType This is the exception type that the new stub will be created
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for.
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@param Stub On successful exit, *Stub contains the newly allocated entry stub.
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**/
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VOID
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CreateEntryStub (
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IN EFI_EXCEPTION_TYPE ExceptionType,
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OUT VOID **Stub
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)
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{
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UINT8 *StubCopy;
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StubCopy = *Stub;
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//
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// Fixup the stub code for this vector
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//
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// The stub code looks like this:
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//
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// 00000000 89 25 00000004 R mov AppEsp, esp ; save stack top
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// 00000006 BC 00008014 R mov esp, offset DbgStkBot ; switch to debugger stack
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// 0000000B 6A 00 push 0 ; push vector number - will be modified before installed
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// 0000000D E9 db 0e9h ; jump rel32
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// 0000000E 00000000 dd 0 ; fixed up to relative address of CommonIdtEntry
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//
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//
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// poke in the exception type so the second push pushes the exception type
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//
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StubCopy[0x0c] = (UINT8) ExceptionType;
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//
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// fixup the jump target to point to the common entry
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//
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*(UINT32 *) &StubCopy[0x0e] = (UINT32) CommonIdtEntry - (UINT32) &StubCopy[StubSize];
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return ;
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}
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/**
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This is the main worker function that manages the state of the interrupt
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handlers. It both installs and uninstalls interrupt handlers based on the
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value of NewCallback. If NewCallback is NULL, then uninstall is indicated.
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If NewCallback is non-NULL, then install is indicated.
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@param NewCallback If non-NULL, NewCallback specifies the new handler to register.
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If NULL, specifies that the previously registered handler should
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be uninstalled.
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@param ExceptionType Indicates which entry to manage.
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@retval EFI_SUCCESS Installing or Uninstalling operation is ok.
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@retval EFI_INVALID_PARAMETER Requested uninstalling a handler from a vector that has
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no handler registered for it
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@retval EFI_ALREADY_STARTED Requested install to a vector that already has a handler registered.
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**/
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EFI_STATUS
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ManageIdtEntryTable (
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CALLBACK_FUNC NewCallback,
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EFI_EXCEPTION_TYPE ExceptionType
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)
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{
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EFI_STATUS Status;
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Status = EFI_SUCCESS;
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if (CompareMem (&IdtEntryTable[ExceptionType].NewDesc, &NullDesc, sizeof (IA32_IDT_GATE_DESCRIPTOR)) != 0) {
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//
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// we've already installed to this vector
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//
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if (NewCallback != NULL) {
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//
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// if the input handler is non-null, error
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//
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Status = EFI_ALREADY_STARTED;
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} else {
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UnhookEntry (ExceptionType);
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}
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} else {
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//
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// no user handler installed on this vector
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//
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if (NewCallback == NULL) {
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//
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// if the input handler is null, error
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//
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Status = EFI_INVALID_PARAMETER;
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} else {
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HookEntry (ExceptionType, NewCallback);
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}
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}
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return Status;
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}
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