aec7465689
Use PcdSpeculationBarrierType in the x86 implementation of SpeculationBarrier() to select between AsmLfence(), AsmCpuid(), and no operation. Cc: Liming Gao <liming.gao@intel.com> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Brian J. Johnson <brian.johnson@hpe.com>
31 lines
648 B
C
31 lines
648 B
C
/** @file
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SpeculationBarrier() function for IA32 and x64.
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Copyright (C) 2018 - 2019, 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 <Library/BaseLib.h>
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/**
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Uses as a barrier to stop speculative execution.
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Ensures that no later instruction will execute speculatively, until all prior
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instructions have completed.
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**/
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VOID
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EFIAPI
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SpeculationBarrier (
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VOID
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)
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{
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if (PcdGet8 (PcdSpeculationBarrierType) == 0x01) {
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AsmLfence ();
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} else if (PcdGet8 (PcdSpeculationBarrierType) == 0x02) {
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AsmCpuid (0x01, NULL, NULL, NULL, NULL);
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}
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}
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