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audk/MdePkg/Library/BaseLib/X86SpeculationBarrier.c

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MdePkg/BaseLib: Introduce new SpeculationBarrier API REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1417 X86 specific BaseLib API AsmLfence() was introduced to address the Spectre Variant 1 (CVE-2017-5753) issue. The purpose of this API is to insert barriers to stop speculative execution. However, the API is highly architecture (X86) specific, and thus should be avoided using across generic code. To address this issue, this patch will add a new BaseLib API called SpeculationBarrier(). Different architectures will have different implementations for this API. For IA32 and x64, the implementation of SpeculationBarrier() will directly call AsmLfence(). For ARM and AARCH64, this patch will add a temporary empty implementation as a placeholder. We hope experts in ARM can help to contribute the actual implementation. For EBC, similar to the ARM and AARCH64 cases, a temporary empty implementation is added. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu <hao.a.wu@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com>
2018-12-21 02:50:39 +01:00
/** @file
SpeculationBarrier() function for IA32 and x64.
Copyright (C) 2018, Intel Corporation. All rights reserved.<BR>
MdePkg: Replace BSD License with BSD+Patent License https://bugzilla.tianocore.org/show_bug.cgi?id=1373 Replace BSD 2-Clause License with BSD+Patent License. This change is based on the following emails: https://lists.01.org/pipermail/edk2-devel/2019-February/036260.html https://lists.01.org/pipermail/edk2-devel/2018-October/030385.html RFCs with detailed process for the license change: V3: https://lists.01.org/pipermail/edk2-devel/2019-March/038116.html V2: https://lists.01.org/pipermail/edk2-devel/2019-March/037669.html V1: https://lists.01.org/pipermail/edk2-devel/2019-March/037500.html Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com>
2019-04-04 01:06:00 +02:00
SPDX-License-Identifier: BSD-2-Clause-Patent
MdePkg/BaseLib: Introduce new SpeculationBarrier API REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1417 X86 specific BaseLib API AsmLfence() was introduced to address the Spectre Variant 1 (CVE-2017-5753) issue. The purpose of this API is to insert barriers to stop speculative execution. However, the API is highly architecture (X86) specific, and thus should be avoided using across generic code. To address this issue, this patch will add a new BaseLib API called SpeculationBarrier(). Different architectures will have different implementations for this API. For IA32 and x64, the implementation of SpeculationBarrier() will directly call AsmLfence(). For ARM and AARCH64, this patch will add a temporary empty implementation as a placeholder. We hope experts in ARM can help to contribute the actual implementation. For EBC, similar to the ARM and AARCH64 cases, a temporary empty implementation is added. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu <hao.a.wu@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com>
2018-12-21 02:50:39 +01:00
**/
#include <Library/BaseLib.h>
/**
Uses as a barrier to stop speculative execution.
Ensures that no later instruction will execute speculatively, until all prior
instructions have completed.
**/
VOID
EFIAPI
SpeculationBarrier (
VOID
)
{
AsmLfence ();
}