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 <michael.kubacki@microsoft.com>
Support multiple PCI segment for PCI_CONFIG2 opcodes.
PiDxeS3BootScriptLib needs to be updated to consume PciSegmentLib
instead of PciLib. That means platforms need to add PciSegmentLib
declaration like below in platform dsc if the PciSegmentLib was
not declared in platform dsc before.
PciSegmentLib|MdePkg/Library/BasePciSegmentLibPci/BasePciSegmentLibPci.inf
For platforms only have one segment,
MdePkg/Library/BasePciSegmentLibPci/BasePciSegmentLibPci.inf is recommended
to be used and declared in platform dsc for PiDxeS3BootScriptLib to have
equivalent functionality with before.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Amy Chan <amy.chan@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
What to do:
1. Remove a hidden assumption "No SMM driver writes BootScript between
SmmReadyToLock and S3SleepEntryCallback".
1.1. Use SmmExitBootServices and SmmLegacyBoot notification to record
AtRuntime flag.
1.2. Use mBootScriptDataBootTimeGuid LockBox to save boot time boot
script data to handle potential INSERT boot script at runtime in SMM.
2. Do not depend on OS to help restore ACPINvs data and use
EfiReservedMemoryType instead of EfiACPIMemoryNVS.
2.1. Use mBootScriptSmmPrivateDataGuid LockBox to save boot script
SMM private data with BackFromS3 = TRUE at runtime. S3 resume
will help restore it to tell the Library the system is back
from S3.
Why to do:
1. The hidden assumption "No SMM driver writes BootScript between
SmmReadyToLock and S3SleepEntryCallback" will cause confusion to
the library's consumer and block the usage of "SMM driver writes
BootScript after SmmReadyToLock". So Remove the assumption.
2. In original code, there might be a corner case that malicious
code patch ACPINvs boot TableLength field same as SMM boot script.
So that it can skip the table restore. The impact is that BootScript
in SMM may be overridden by malicious code.
--------------------
CopyMem ((VOID*)&TableHeader, (VOID*)mS3BootScriptTablePtr->TableBase, sizeof(EFI_BOOT_SCRIPT_TABLE_HEADER));
if (mS3BootScriptTablePtr->TableLength + sizeof(EFI_BOOT_SCRIPT_TERMINATE) != TableHeader.TableLength) { // TableLength is in NVS
......
//
// NOTE: We should NOT use TableHeader.TableLength, because it is already updated to be whole length.
//
mS3BootScriptTablePtr->TableLength = (UINT32)(mLockBoxLength - sizeof(EFI_BOOT_SCRIPT_TERMINATE)); ? This line can be skipped.
--------------------
So use EfiReservedMemoryType instead of EfiACPIMemoryNVS as the code
has been updated to not depend on OS to help restore ACPINvs data.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18467 6f19259b-4bc3-4df7-8a09-765794883524
