CloverBootloader/OvmfPkg/Library/NestedInterruptTplLib/Iret.c

63 lines
1.3 KiB
C

/** @file
Force interrupt handler to return with interrupts still disabled.
Copyright (C) 2022, Fen Systems Ltd.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include "Iret.h"
/**
Force interrupt handler to return with interrupts still disabled.
@param SystemContext A pointer to the system context when the
interrupt occurred.
**/
VOID
DisableInterruptsOnIret (
IN OUT EFI_SYSTEM_CONTEXT SystemContext
)
{
#if defined (MDE_CPU_X64)
IA32_EFLAGS32 Rflags;
//
// Get flags from system context.
//
Rflags.UintN = SystemContext.SystemContextX64->Rflags;
ASSERT (Rflags.Bits.IF);
//
// Clear interrupts-enabled flag.
//
Rflags.Bits.IF = 0;
SystemContext.SystemContextX64->Rflags = Rflags.UintN;
#elif defined (MDE_CPU_IA32)
IA32_EFLAGS32 Eflags;
//
// Get flags from system context.
//
Eflags.UintN = SystemContext.SystemContextIa32->Eflags;
ASSERT (Eflags.Bits.IF);
//
// Clear interrupts-enabled flag.
//
Eflags.Bits.IF = 0;
SystemContext.SystemContextIa32->Eflags = Eflags.UintN;
#else
#error "Unsupported CPU"
#endif
}