On Mon, Mar 26, 2018 at 10:29 PM, Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote: > To get an environment value, Kconfig needs to define a symbol using > "option env=" syntax. It is tedious to add a config entry for each > environment given that we need more environments such as 'CC', 'AS', > 'srctree' etc. to evaluate the compiler capability in Kconfig. > > Adding '$' to symbols is weird. Kconfig can reference symbols directly > like this: > > config FOO > string > default BAR > > So, I want to use the following syntax to get environment 'BAR' from > the system: > > config FOO > string > default $BAR > > Looking at the code, the symbols prefixed with 'S' are expanded by: > - conf_expand_value() > This is used to expand 'arch/$ARCH/defconfig' and 'defconfig_list' > - expand_string_value() > This is used to expand strings in 'source' and 'mainmenu' > > All of them are fixed values independent of user configuration. So, > this kind of syntax should be moved to simply take the environment. > > 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 be given from the environment. > > ARCH_DEFCONFIG is a normal symbol, so it should be simply referenced > by 'default ARCH_DEFCONFIG'. > > The environments are expanding in the lexer; when '$' is encountered, > it is expanded, and resulted strings are pushed back to the input > stream. This makes the implementation simpler. > > For example, the following code works. > > [Example code] > > config TOOLCHAIN_LIST > string > default "My tools: CC=$CC, AS=$AS, CPP=$CPP" > > [Result] > > $ make -s alldefconfig && tail -n 1 .config > CONFIG_TOOLCHAIN_LIST="My tools: CC=gcc, AS=as, CPP=gcc -E" > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> For easier review this patch could maybe get split into a couple (i.e. refactoring of things like env_write_dep()) but it's probably fine as-is. :) Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees -- Kees Cook Pixel Security -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
