MdePkg/BaseLib: Add new AsmLfence API

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1193

This commit will add a new BaseLib API AsmLfence(). This API will perform
a serializing operation on all load-from-memory instructions that were
issued prior to the call of this function. Please note that this API is
only available on IA-32 and x64.

The purpose of adding this API is to mitigate of the [CVE-2017-5753]
Bounds Check Bypass issue when untrusted data are being processed within
SMM. More details can be referred at the 'Bounds check bypass mitigation'
section at the below link:

https://software.intel.com/security-software-guidance/insights/host-firmware-speculative-execution-side-channel-mitigation

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index 2fae312f2f..8cc086983d 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -7697,6 +7697,19 @@ AsmWriteTr (
   );

 

 /**

+  Performs a serializing operation on all load-from-memory instructions that

+  were issued prior the AsmLfence function.

+

+  Executes a LFENCE instruction. This function is only available on IA-32 and x64.

+

+**/

+VOID

+EFIAPI

+AsmLfence (

+  VOID

+  );

+

+/**

   Patch the immediate operand of an IA32 or X64 instruction such that the byte,

   word, dword or qword operand is encoded at the end of the instruction's

   binary representation.