Tianocore/edk2.git/MdeModulePkg/Include/Guid/SmmVariableCommon.h, branch master

MdeModulePkg: Replace include guards with #pragma once

2026-02-23T21:01:28+00:00

Replace traditional `#ifndef`/`#define`/`#endif` include guards with `#pragma` once. `#pragma once` is a widely supported preprocessor directive that prevents header files from being included multiple times. It is supported by all toolchains used to build edk2: GCC, Clang/LLVM, and MSVC. Compared to macro-based include guards, `#pragma once`: - Eliminates the risk of macro name collisions or copy/paste errors where two headers inadvertently use the same guard macro. - Eliminate inconsistency in the way include guard macros are named (e.g., some files use `__FILE_H__`, others use `FILE_H_`, etc.). - Reduces boilerplate (three lines replaced by one). - Avoids polluting the macro namespace with guard symbols. - Can improve build times as the preprocessor can skip re-opening the file entirely, rather than re-reading it to find the matching `#endif` ("multiple-include optimization"). - Note that some compilers may already optimize traditional include guards, by recognzining the idiomatic pattern. This change is made acknowledging that overall portability of the code will technically be reduced, as `#pragma once` is not part of the C/C++ standards. However, this is considered acceptable given: 1. edk2 already defines a subset of supported compilers in BaseTools/Conf/tools_def.template, all of which have supported `#pragma once` for over two decades. 2. There have been concerns raised to the project about inconsistent include guard naming and potential macro collisions. Approximate compiler support dates: - MSVC: Supported since Visual C++ 4.2 (1996) - GCC: Supported since 3.4 (2004) (http://gnu.ist.utl.pt/software/gcc/gcc-3.4/changes.html) - Clang (LLVM based): Since initial release in 2007 Signed-off-by: Michael Kubacki

MdeModulePkg: VariableSmmRuntimeDxe: Use MM communicate v3

2025-06-26T21:43:56+00:00

As MM cores start to support MM communciate v3. This change moves the variable driver to use MM communicate v3 if it is available, otherwise the driver will fallback to v2 to keep the same functionality. Signed-off-by: Kun Qin

MdeModulePkg: Apply uncrustify changes

2021-12-07T17:24:28+00:00

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3737 Apply uncrustify changes to .c/.h files in the MdeModulePkg package Cc: Andrew Fish Cc: Leif Lindholm Cc: Michael D Kinney Signed-off-by: Michael Kubacki Reviewed-by: Liming Gao

MdeModulePkg/VariableSmmRuntimeDxe: switch to MM communicate 2

2020-05-12T19:23:44+00:00

Switch to the new MM communicate 2 protocol which supports both traditional and standalone MM. Signed-off-by: Ard Biesheuvel Reviewed-by: Liming Gao Reviewed-by: Sami Mujawar

MdeModulePkg/Variable: Add RT GetVariable() cache support

2019-11-06T05:55:54+00:00

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2220 This change reduces SMIs for GetVariable () by maintaining a UEFI variable cache in Runtime DXE in addition to the pre- existing cache in SMRAM. When the Runtime Service GetVariable() is invoked, a Runtime DXE cache is used instead of triggering an SMI to VariableSmm. This can improve overall system performance by servicing variable read requests without rendezvousing all cores into SMM. The runtime cache can be disabled with by setting the FeaturePCD gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache to FALSE. If the PCD is set to FALSE, the runtime cache will not be used and an SMI will be triggered for Runtime Service GetVariable () and GetNextVariableName () invocations. The following are important points regarding the behavior of the variable drivers when the variable runtime cache is enabled. 1. All of the non-volatile storage contents are loaded into the cache upon driver load. This one time load operation from storage is preferred as opposed to building the cache on demand. An on- demand cache would require a fallback SMI to load data into the cache as variables are requested. 2. SetVariable () requests will continue to always trigger an SMI. This occurs regardless of whether the variable is volatile or non-volatile. 3. Both volatile and non-volatile variables are cached in a runtime buffer. As is the case in the current EDK II variable driver, they continue to be cached in separate buffers. 4. The cache in Runtime DXE and SMM are intended to be exact copies of one another. All SMM variable accesses only return data from the SMM cache. The runtime caches are only updated after the variable I/O operation is successful in SMM. The runtime caches are only updated from SMM. 5. Synchronization mechanisms are in place to ensure the runtime cache content integrity with the SMM cache. These may result in updates to runtime cache that are the same in content but different in offset and size from updates to the SMM cache. When using SMM variables with runtime cache enabled, two caches will now be present. 1. "Runtime Cache" - Maintained in VariableSmmRuntimeDxe. Used to service Runtime Services GetVariable () and GetNextVariableName () callers. 2. "SMM Cache" - Maintained in VariableSmm to service SMM GetVariable () and GetNextVariableName () callers. a. This cache is retained so SMM modules do not operate on data outside SMRAM. Because a race condition can occur if an SMI occurs during the execution of runtime code reading from the runtime cache, a runtime cache read lock is introduced that explicitly moves pending updates from SMM to the runtime cache if an SMM update occurs while the runtime cache is locked. Note that it is not expected a Runtime services call will interrupt SMM processing since all CPU cores rendezvous in SMM. It is possible to view UEFI variable read and write statistics by setting the gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics FeaturePcd to TRUE and using the VariableInfo UEFI application in MdeModulePkg to dump variable statistics to the console. By doing so, a user can view the number of GetVariable () hits from the Runtime DXE variable driver (Runtime Cache hits) and the SMM variable driver (SMM Cache hits). SMM Cache hits for GetVariable () will occur when SMM modules invoke GetVariable (). Cc: Dandan Bi Cc: Ard Biesheuvel Cc: Eric Dong Cc: Laszlo Ersek Cc: Liming Gao Cc: Michael D Kinney Cc: Ray Ni Cc: Jian J Wang Cc: Hao A Wu Cc: Jiewen Yao Signed-off-by: Michael Kubacki Reviewed-by: Jian J Wang

MdeModulePkg: Replace BSD License with BSD+Patent License

2019-04-09T17:58:08+00:00

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 Reviewed-by: Hao Wu Reviewed-by: Jian J Wang

MdeModulePkg Variable: Merge from Auth Variable driver in SecurityPkg

2015-07-01T03:08:29+00:00

What to do: 1. Merge from Auth Variable driver in SecurityPkg to Variable drive in MdeModulePkg. Then the merged Variable driver in MdeModulePkg will link to AuthVariableLib and TpmMeasurementLib. AuthVariableLibNull and TpmMeasurementLibNull in MdeModulePkg could be used for non auth variable support. AuthVariableLib and DxeTpmMeasurementLib in SecurityPkg may be used for auth variable support. Why to do: 1. Remove code duplication and reduce maintenance effort. After auth variable service separated from Auth Variable driver in SecurityPkg to AuthVariableLib. The remaining code logic of Auth Variable driver in SecurityPkg will be almost same with Variable driver in MdeModulePkg. Now it is to merge them. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Star Zeng Reviewed-by: Jiewen Yao Reviewed-by: Liming Gao git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17765 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg Variable: Implement VarCheck PROTOCOL

2015-01-05T03:38:36+00:00

and follow UEFI spec to check UEFI defined variables. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Star Zeng Reviewed-by: Jiewen Yao git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16579 6f19259b-4bc3-4df7-8a09-765794883524

Add EDKII_VARIABLE_LOCK_PROTOCOL and the implementation in MdeModulePkg variable drivers.

2013-05-17T03:49:35+00:00

Add code in BdsDxe driver to call the protocol to mark the read-only variables defined in the UEFI Spec. Signed-off-by: Ruiyu Ni Reviewed-by: Guo Dong Reviewed-by: Star Zeng git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14372 6f19259b-4bc3-4df7-8a09-765794883524

Update SMM variable DXE driver GetNextVariable interface to comply with UEFI spec

2013-04-12T05:59:11+00:00

VariableNameSize is the returned buffer size. GetNextVariable should behavior correct if it is bigger than SMM communication buffer or less than string size of VariableName. Signed-off-by: Chao Zhang Reviewed-by : Dong Guo Reviewed-by : Fu Siyuan Reviewed-by : Zeng Star git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14258 6f19259b-4bc3-4df7-8a09-765794883524