Import edk2-stable202005vendor/edk2/ca407c7246bf405da6d9b1b9d93e5e7f17b4b1f9vendor/edk2

As with the previous import, only the MdePkg subdirectory has been
brought in. The line-endings were also converted using:

% find . -type f | xargs -n 1 sed -I.BAK -e `printf "s/\r//g"`
% find . -name \*.BAK | xargs rm

1 files changed, 33 insertions, 0 deletions

diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm
new file mode 100644
index 000000000000..3b4d5c3f501d
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm
@@ -0,0 +1,33 @@
+;------------------------------------------------------------------------------
+;
+; SpeculationBarrier() for AArch64
+;
+; Copyright (c) 2019, Linaro Ltd. All rights reserved.
+;
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+    EXPORT SpeculationBarrier
+
+    AREA MemoryBarriers, CODE, READONLY
+
+;/**
+;  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
+;  );
+;
+SpeculationBarrier
+    dsb
+    isb
+    bx    lr
+
+  END