On 04/30/19 03:30, Michael D Kinney wrote:
> Use PcdSpeculationBarrierType in the x86 implementation
> of SpeculationBarrier() to select between AsmLfence(),
> AsmCpuid(), and no operation.
>
> Cc: Liming Gao <liming....@intel.com>
> Signed-off-by: Michael D Kinney <michael.d.kin...@intel.com>
> ---
> MdePkg/Library/BaseLib/BaseLib.inf | 1 +
> MdePkg/Library/BaseLib/X86SpeculationBarrier.c | 8 ++++++--
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/MdePkg/Library/BaseLib/BaseLib.inf
> b/MdePkg/Library/BaseLib/BaseLib.inf
> index 533e83e0b2..3586beb0ab 100644
> --- a/MdePkg/Library/BaseLib/BaseLib.inf
> +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> @@ -394,6 +394,7 @@ [Pcd]
> gEfiMdePkgTokenSpaceGuid.PcdMaximumAsciiStringLength ##
> SOMETIMES_CONSUMES
> gEfiMdePkgTokenSpaceGuid.PcdMaximumUnicodeStringLength ##
> SOMETIMES_CONSUMES
> gEfiMdePkgTokenSpaceGuid.PcdControlFlowEnforcementPropertyMask ##
> SOMETIMES_CONSUMES
> + gEfiMdePkgTokenSpaceGuid.PcdSpeculationBarrierType ##
> SOMETIMES_CONSUMES
>
> [FeaturePcd]
> gEfiMdePkgTokenSpaceGuid.PcdVerifyNodeInList ## CONSUMES
So, based on the example of
MdePkg/Library/SecPeiDxeTimerLibCpu/SecPeiDxeTimerLibCpu.inf
and a few other INF files, I think we could use
[Pcd.IA32, Pcd.X64]
here as well.
Just an idea.
Reviewed-by: Laszlo Ersek <ler...@redhat.com>
Thanks
Laszlo
> diff --git a/MdePkg/Library/BaseLib/X86SpeculationBarrier.c
> b/MdePkg/Library/BaseLib/X86SpeculationBarrier.c
> index 8e5f983bb8..b28fd8de9b 100644
> --- a/MdePkg/Library/BaseLib/X86SpeculationBarrier.c
> +++ b/MdePkg/Library/BaseLib/X86SpeculationBarrier.c
> @@ -1,7 +1,7 @@
> /** @file
> SpeculationBarrier() function for IA32 and x64.
>
> - Copyright (C) 2018, Intel Corporation. All rights reserved.<BR>
> + Copyright (C) 2018 - 2019, Intel Corporation. All rights reserved.<BR>
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
>
> @@ -22,5 +22,9 @@ SpeculationBarrier (
> VOID
> )
> {
> - AsmLfence ();
> + if (PcdGet8 (PcdSpeculationBarrierType) == 0x01) {
> + AsmLfence ();
> + } else if (PcdGet8 (PcdSpeculationBarrierType) == 0x02) {
> + AsmCpuid (0x01, NULL, NULL, NULL, NULL);
> + }
> }
>
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