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![Masahiro Yamada](/assets/img/avatar_default.png)
To get access to environment variables, Kconfig needs to define a symbol using "option env=" syntax. It is tedious to add a symbol entry for each environment variable given that we need to define much more such as 'CC', 'AS', 'srctree' etc. to evaluate the compiler capability in Kconfig. Adding '$' for symbol references is grammatically inconsistent. Looking at the code, the symbols prefixed with 'S' are expanded by: - conf_expand_value() This is used to expand 'arch/$ARCH/defconfig' and 'defconfig_list' - sym_expand_string_value() This is used to expand strings in 'source' and 'mainmenu' All of them are fixed values independent of user configuration. So, they can be changed into the direct expansion instead of symbols. This change makes the code much cleaner. The bounce symbols 'SRCARCH', 'ARCH', 'SUBARCH', 'KERNELVERSION' are gone. sym_init() hard-coding 'UNAME_RELEASE' is also gone. 'UNAME_RELEASE' should be replaced with an environment variable. ARCH_DEFCONFIG is a normal symbol, so it should be simply referenced without '$' prefix. The new syntax is addicted by Make. The variable reference needs parentheses, like $(FOO), but you can omit them for single-letter variables, like $F. Yet, in Makefiles, people tend to use the parenthetical form for consistency / clarification. At this moment, only the environment variable is supported, but I will extend the concept of 'variable' later on. The variables are expanded in the lexer so we can simplify the token handling on the parser side. For example, the following code works. [Example code] config MY_TOOLCHAIN_LIST string default "My tools: CC=$(CC), AS=$(AS), CPP=$(CPP)" [Result] $ make -s alldefconfig && tail -n 1 .config CONFIG_MY_TOOLCHAIN_LIST="My tools: CC=gcc, AS=as, CPP=gcc -E" Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Kees Cook <keescook@chromium.org>
60 lines
777 B
Text
60 lines
777 B
Text
# SPDX-License-Identifier: GPL-2.0
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config UML
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bool
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default y
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select ARCH_HAS_KCOV
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select HAVE_ARCH_AUDITSYSCALL
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select HAVE_ARCH_SECCOMP_FILTER
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select HAVE_UID16
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select HAVE_FUTEX_CMPXCHG if FUTEX
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select HAVE_DEBUG_KMEMLEAK
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select GENERIC_IRQ_SHOW
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select GENERIC_CPU_DEVICES
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select GENERIC_CLOCKEVENTS
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select HAVE_GCC_PLUGINS
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select TTY # Needed for line.c
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config MMU
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bool
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default y
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config NO_IOMEM
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def_bool y
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config ISA
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bool
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config SBUS
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bool
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config PCI
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bool
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config PCMCIA
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bool
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config TRACE_IRQFLAGS_SUPPORT
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bool
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default y
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config LOCKDEP_SUPPORT
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bool
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default y
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config STACKTRACE_SUPPORT
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bool
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default y
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select STACKTRACE
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config GENERIC_CALIBRATE_DELAY
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bool
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default y
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config HZ
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int
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default 100
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config NR_CPUS
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int
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range 1 1
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default 1
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