UEFI的编译细节
UEFI编译
uefi的常规编译方式为：build -t CompilerName -A Arch -p PkgName -j logfile
UEFI的编译细节展开
通常UEFI的编译包括以下三个步骤：
. edksetup.sh
make -C BaseTools
build -t CompilerName -A Arch -p PkgName -j logfile
edksetup.sh
上述准备过程中,edksetup.sh的工作是准备工作的核心,具体来看一下:
SCRIPTNAME="edksetup.sh"
RECONFIG=FALSE
#使用帮助
function HelpMsg()
{
echo "Usage: $SCRIPTNAME [Options]"
echo
echo "The system environment variable, WORKSPACE, is always set to the current"
echo "working directory."
echo
echo "Options: "
echo " --help, -h, -? Print this help screen and exit."
echo
echo " --reconfig Overwrite the WORKSPACE/Conf/*.txt files with the"
echo " template files from the BaseTools/Conf directory."
echo
echo Please note: This script must be \'sourced\' so the environment can be changed.
echo ". $SCRIPTNAME"
echo "source $SCRIPTNAME"
}
# 设定工作目录
function SetWorkspace()
{
#
# If WORKSPACE is already set, then we can return right now
#
if [ -n "$WORKSPACE" ]
then
return 0
fi
if [ ! ${BASH_SOURCE[0]} -ef ./edksetup.sh ] && [ -z "$PACKAGES_PATH" ]
then
echo Run this script from the base of your tree. For example:
echo " cd /Path/To/Edk/Root"
echo " . edksetup.sh"
return 1
fi
#
# Check for BaseTools/BuildEnv before dirtying the user's environment.
#
if [ ! -f BaseTools/BuildEnv ] && [ -z "$EDK_TOOLS_PATH" ]
then
echo BaseTools not found in your tree, and EDK_TOOLS_PATH is not set.
echo Please point EDK_TOOLS_PATH at the directory that contains
echo the EDK2 BuildEnv script.
return 1
fi
#
# Set $WORKSPACE
#
export WORKSPACE=`pwd`
return 0
}
# 设定环境变量
function SetupEnv()
{
# !!环境变量的重要内容在BuildEnv里面!!
if [ -n "$EDK_TOOLS_PATH" ]
then
. $EDK_TOOLS_PATH/BuildEnv
elif [ -f "$WORKSPACE/BaseTools/BuildEnv" ]
then
. $WORKSPACE/BaseTools/BuildEnv
elif [ -n "$PACKAGES_PATH" ]
then
PATH_LIST=$PACKAGES_PATH
PATH_LIST=${PATH_LIST//:/ }
for DIR in $PATH_LIST
do
if [ -f "$DIR/BaseTools/BuildEnv" ]
then
export EDK_TOOLS_PATH=$DIR/BaseTools
. $DIR/BaseTools/BuildEnv
break
fi
done
else
echo BaseTools not found in your tree, and EDK_TOOLS_PATH is not set.
echo Please check that WORKSPACE or PACKAGES_PATH is not set incorrectly
echo in your shell, or point EDK_TOOLS_PATH at the directory that contains
echo the EDK2 BuildEnv script.
return 1
fi
}
# 设定环境变量和工作目录的入口
function SourceEnv()
{
SetWorkspace &&
SetupEnv
}
# 文件运行的入口,获取运行参数并按需执行
I=$#
while [ $I -gt 0 ]
do
case "$1" in
BaseTools)
# Ignore argument for backwards compatibility
shift
;;
--reconfig)
RECONFIG=TRUE
shift
;;
-?|-h|--help|*)
HelpMsg
break
;;
esac
I=$(($I - 1))
done
if [ $I -gt 0 ]
then
return 1
fi
SourceEnv
unset SCRIPTNAME RECONFIG
return $?
上面核心的内容在BuildEnv里
# 同样在设置环境变量
SetWorkspace() {
#
# If WORKSPACE is already set, then we can return right now
#
if [ -n "$WORKSPACE" ]
then
return 0
fi
#
# Set $WORKSPACE
#
export WORKSPACE=`pwd`
return 0
}
# 恢复配置
RestorePreviousConfiguration() {
#
# Restore previous configuration
#
if [ -z "$CONF_PATH" ]
then
export CONF_PATH=$WORKSPACE/Conf
if [ ! -d $WORKSPACE/Conf ] && [ -n "$PACKAGES_PATH" ]
then
PATH_LIST=${PACKAGES_PATH//:/ }
for DIR in $PATH_LIST
do
if [ -d $DIR/Conf ]
then
export CONF_PATH=$DIR/Conf
break
fi
done
fi
fi
PREVIOUS_CONF_FILE=$CONF_PATH/BuildEnv.sh
if [ -e $PREVIOUS_CONF_FILE ]
then
echo Loading previous configuration from $PREVIOUS_CONF_FILE
. $PREVIOUS_CONF_FILE
fi
}
# 生成Shell脚本去设置变量
GenerateShellCodeToSetVariable() {
VARIABLE=$1
OUTPUT_FILE=$2
VAR_VALUE="echo \${${VARIABLE}}"
VAR_VALUE=`eval $VAR_VALUE`
echo "if [ -z \"\$${VARIABLE}\" ]" >> $OUTPUT_FILE
echo "then" >> $OUTPUT_FILE
echo " export ${VARIABLE}=${VAR_VALUE}" >> $OUTPUT_FILE
echo "fi" >> $OUTPUT_FILE
}
# 生成shell脚本去更新环境变量
GenerateShellCodeToUpdatePath() {
OUTPUT_FILE=$1
echo "if [ -e $EDK_TOOLS_PATH_BIN ]" >> $OUTPUT_FILE
echo "then" >> $OUTPUT_FILE
echo " if [ "\${PATH/$EDK_TOOLS_PATH_BIN/}" == "\$PATH" ]" >> $OUTPUT_FILE
echo " then" >> $OUTPUT_FILE
echo " export PATH=$EDK_TOOLS_PATH_BIN:\$PATH" >> $OUTPUT_FILE
echo " fi" >> $OUTPUT_FILE
echo "fi" >> $OUTPUT_FILE
}
# 存储当前配置信息
StoreCurrentConfiguration() {
#
# Write configuration to a shell script to allow for configuration to be
# easily reloaded.
#
OUTPUT_FILE=$CONF_PATH/BuildEnv.sh
#echo Storing current configuration into $OUTPUT_FILE
echo "# Auto-generated by ${BASH_SOURCE[0]}" >| $OUTPUT_FILE
GenerateShellCodeToSetVariable WORKSPACE $OUTPUT_FILE
GenerateShellCodeToSetVariable EDK_TOOLS_PATH $OUTPUT_FILE
GenerateShellCodeToUpdatePath $OUTPUT_FILE
}
# 设定配置信息的目录
SetEdkToolsPath() {
#
# If EDK_TOOLS_PATH is already set, then we can return right now
#
if [ -n "$EDK_TOOLS_PATH" ]
then
return 0
fi
#
# Try $CONF_PATH/EdkTools
#
if [ -e $CONF_PATH/EdkTools ]
then
export EDK_TOOLS_PATH=$CONF_PATH/EdkTools
return 0
fi
#
# Try $CONF_PATH/BaseToolsSource
#
if [ -e $CONF_PATH/BaseToolsSource ]
then
export EDK_TOOLS_PATH=$CONF_PATH/BaseToolsSource
return 0
fi
#
# Try $WORKSPACE/BaseTools
#
if [ -e $WORKSPACE/BaseTools ]
then
export EDK_TOOLS_PATH=$WORKSPACE/BaseTools
return 0
fi
#
# Try $PACKAGES_PATH
#
if [ -n "$PACKAGES_PATH"]
then
PATH_LIST=${PACKAGES_PATH//:/ }
for DIR in $PATH_LIST
do
if [ -d $DIR/BaseTools ]
then
export EDK_TOOLS_PATH=$DIR/BaseTools
return 0
fi
done
fi
echo "Unable to determine EDK_TOOLS_PATH"
echo
echo "You may need to download the 'BaseTools' from buildtools.tianocore.org."
echo "After downloading, either create a symbolic link to the source at"
echo "\$WORKSPACE/Conf/BaseToolsSource, or set the EDK_TOOLS_PATH environment"
echo "variable."
}
# 由系统类型,获取相关的子文件夹名称
GetBaseToolsBinSubDir() {
#
# Figure out a uniq directory name from the uname command
#
UNAME_DIRNAME=`uname -sm`
UNAME_DIRNAME=${UNAME_DIRNAME// /-}
UNAME_DIRNAME=${UNAME_DIRNAME//\//-}
echo $UNAME_DIRNAME
}
# 结合上一个函数,得到edk下二进制存放目录
GetEdkToolsPathBinDirectory() {
#
# Figure out a uniq directory name from the uname command
#
BIN_SUB_DIR=`GetBaseToolsBinSubDir`
if [ -e $EDK_TOOLS_PATH/BinWrappers/$BIN_SUB_DIR ]
then
EDK_TOOLS_PATH_BIN=$EDK_TOOLS_PATH/BinWrappers/$BIN_SUB_DIR
else
EDK_TOOLS_PATH_BIN=$EDK_TOOLS_PATH/Bin/$BIN_SUB_DIR
fi
echo $EDK_TOOLS_PATH_BIN
}
# 还是环境变量
AddDirToStartOfPath() {
DIRNAME=$1
PATH=$DIRNAME:$DIRNAME:$DIRNAME:$PATH
PATH=${PATH//$DIRNAME:/}
PATH=$DIRNAME:$PATH
export PATH
}
AddEdkToolsToPath() {
#
# If EDK_TOOLS_PATH is not set, then we cannot update PATH
#
if [ -z "$EDK_TOOLS_PATH" ]
then
return 1
fi
EDK_TOOLS_PATH_BIN=`GetEdkToolsPathBinDirectory`
AddDirToStartOfPath $EDK_TOOLS_PATH/BinWrappers/PosixLike
AddDirToStartOfPath $EDK_TOOLS_PATH_BIN
}
# !!拷贝配置文件模板!!
# 把BaseTools/Conf下的模板文件,拷贝到Conf下
# 拷贝的模板文件为:build_rule, tools_def, target
CopySingleTemplateFile() {
SRC_FILENAME=Conf/$1.template
DST_FILENAME=$CONF_PATH/$1.txt
if [ -e $DST_FILENAME ]
then
[ $RECONFIG != TRUE ] && return
fi
echo "Copying \$EDK_TOOLS_PATH/$SRC_FILENAME"
echo " to $DST_FILENAME"
SRC_FILENAME=$EDK_TOOLS_PATH/$SRC_FILENAME
cp $SRC_FILENAME $DST_FILENAME
}
CopyTemplateFiles() {
CopySingleTemplateFile build_rule
CopySingleTemplateFile tools_def
CopySingleTemplateFile target
}
# 脚本入口
ScriptMain() {
SetWorkspace
if [ -z $WORKSPACE ]
then
echo "Failure setting WORKSPACE"
return 1
fi
RestorePreviousConfiguration
SetEdkToolsPath
if [ -z $EDK_TOOLS_PATH ]
then
return 1
fi
AddEdkToolsToPath
if [ $? -ne 0 ]
then
echo "Failure adding EDK Tools into PATH!"
return 1
fi
StoreCurrentConfiguration
echo WORKSPACE: $WORKSPACE
echo EDK_TOOLS_PATH: $EDK_TOOLS_PATH
echo CONF_PATH: $CONF_PATH
CopyTemplateFiles
}
#
# Run the main function
#
ScriptMain
make -C BaseTools
上面所述编译前的准备中,Basetools会在edksetup.sh没有生效时执行,也稍作分析吧
来看一眼其中的的Makefile
!IFNDEF BASE_TOOLS_PATH
!ERROR "BASE_TOOLS_PATH is not set! Please run toolsetup.bat first!"
!ENDIF
SUBDIRS = $(BASE_TOOLS_PATH)\Source\C $(BASE_TOOLS_PATH)\Source\Python
//#编译依赖项是c和python
all: c python
c :
@$(BASE_TOOLS_PATH)\Source\C\Makefiles\NmakeSubdirs.bat all $(BASE_TOOLS_PATH)\Source\C
python:
@$(BASE_TOOLS_PATH)\Source\C\Makefiles\NmakeSubdirs.bat all $(BASE_TOOLS_PATH)\Source\Python
subdirs: $(SUBDIRS)
@$(BASE_TOOLS_PATH)\Source\C\Makefiles\NmakeSubdirs.bat all $**
.PHONY: clean
clean:
@$(BASE_TOOLS_PATH)\Source\C\Makefiles\NmakeSubdirs.bat clean $(SUBDIRS)
.PHONY: cleanall
cleanall:
@$(BASE_TOOLS_PATH)\Source\C\Makefiles\NmakeSubdirs.bat cleanall $(SUBDIRS)
需要编译相应的C和Python库,但是使用的是bat脚本,真正make输出的log确是正常的shell输出,这点还不知道怎么处理的,先分析到这,之后继续吧TODO
Build
build才是真正编译的开始!
build -a ARM64 -p /home/mxdon/clone/UEFI/uefi-arm/ArmCodePkg/SampleCode/Desktop/Script/Arm.dsc -t GCC83 -b DEBUG -j log.txt
显然,执行者是build,所以看看build的实质
先找到build在哪
[mxdon@5 uefi-arm]$ cat `which build`
#!/usr/bin/env bash
#python `dirname $0`/RunToolFromSource.py `basename $0` $*
# If a python2 command is available, use it in preference to python
if command -v python2 >/dev/null 2>&1; then
python_exe=python2
fi
full_cmd=${BASH_SOURCE:-$0} # see http://mywiki.wooledge.org/BashFAQ/028 for a discussion of why $0 is not a good choice here
dir=$(dirname "$full_cmd")
cmd=${full_cmd##*/}
export PYTHONPATH="$dir/../../Source/Python"
exec "${python_exe:-python}" "$dir/../../Source/Python/$cmd/$cmd.py" "$@"
可以看到，先是设置了环境，然后执行$cmd.py $@来执行build
所以再找到cmd在Source/Python下面，所以执行什么命令，就是在运行该命令名称下的以该命令命名的py文件。
所以执行build的时候是执行的build.py，AutoGen执行AutoGen.py以此类推，由于python文件较长，此后选择性展开。
如果查看打印log的话，也可以发现入口是build.py
ok,继续看，在编译的log中,首先打印的是:
Build environment: Linux-4.18.0-305.10.2.el8_4.x86_64-x86_64-with-centos-8.4.2105
Build start time: 15:00:53, Jan.04 2022
对应于build.py中:
EdkLogger.quiet("Build environment: %s" % platform.platform())
EdkLogger.quiet(time.strftime("Build start time: %H:%M:%S, %b.%d %Y\n", time.localtime()));
相关变量在之前获取.
类似的分析,log中设定环境变量:
WORKSPACE = /home/mxdon/clone/UEFI/uefi-arm
ECP_SOURCE = /home/mxdon/clone/UEFI/uefi-arm/EdkCompatibilityPkg
EDK_SOURCE = /home/mxdon/clone/UEFI/uefi-arm/EdkCompatibilityPkg
EFI_SOURCE = /home/mxdon/clone/UEFI/uefi-arm/EdkCompatibilityPkg
EDK_TOOLS_PATH = /home/mxdon/clone/UEFI/uefi-arm/BaseTools/
CONF_PATH = /home/mxdon/clone/UEFI/uefi-arm/Conf
Architecture(s) = ARM64
Build target = DEBUG
Toolchain = GCC83
Active Platform = /home/mxdon/clone/UEFI/uefi-arm/ArmCodePkg/SampleCode/Desktop/Script/Arm.dsc
Flash Image Definition = /home/mxdon/clone/UEFI/uefi-arm/ArmCodePkg/SampleCode/Desktop/Script/Arm.fdf
对应build.py中的则是:
CheckEnvVariable() ->
MyBuild = Build(Target, Workspace, Option) ->
__init__() ->
EdkLogger.quiet(...)
类似的分析不再赘述,简要说明如下:
main->MyBuild->Build->__init__->... #设定及检验用于build的环境,包括加载target.txt中的编译器,dsc文件中的描述等,用于生成最终的编译规则.
->_BuildPlatform->WorkspaceAutoGen->PlatformAutoGen #通过解析FDF文件和INF文件,生成相应的C代码(宏变量)和Makefile(编译规则)
->_BuildPa->_GenFfsCmd #编译模块
->_CollectModuleMapBuffer #根据PCD修改EFI的内存分布,并获取modules的内存分布,用于重定位modules,链接生成最终的FD文件
->_Build #编译模块
->_CollectFvMapBuffer #获取重定位FV的信息
大概流程如上,其中重定位相关的内容调用_RebaseModule->LaunchCommand[GenFw...],其中LaunchCommand也是在Build中执行make的途径.
从前面知道,执行的命令与其文件名相同,GenFw所用到的文件不是Python,而是C/GenFw/GenFw.c,其中具体细节暂不展开.
重定位
TODO
总结
UEFI是像一个魔改的Kernel,图形化,文字功能,网络功能都具备,在一定条件下可以变成内核,具有学习的价值和意义.
尤其,UEFI比内核简单许多,作为一个嵌入式C的大型项目来说是非常不错的,基于此,再看上述分析过程,整个UEFI的核心也无非就是C,Python,Shell(Makefile)这三种语言.也竟然有这三种语言.
我的意思是,项目开发中,只会一种语言可能越来越不够了,技多不压身,多学吧~
最后，点个关注不迷路
公众号：孟游先生的旅游笔记
