8b59cd81dc
Commit 21c54b7747 ("kconfig: show compiler version text in the top
comment") added the environment variable, CC_VERSION_TEXT in the comment
of the top Kconfig file. It can detect the compiler update, and invoke
the syncconfig because all environment variables referenced in Kconfig
files are recorded in include/config/auto.conf.cmd
This commit makes it a CONFIG option in order to ensure the full rebuild
when the compiler is updated.
This works like follows:
include/config/kconfig.h contains "CONFIG_CC_VERSION_TEXT" in the comment
block.
The top Makefile specifies "-include $(srctree)/include/linux/kconfig.h"
to guarantee it is included from all kernel source files.
fixdep parses every source file and all headers included from it,
searching for words prefixed with "CONFIG_". Then, fixdep finds
CONFIG_CC_VERSION_TEXT in include/config/kconfig.h and adds
include/config/cc/version/text.h into every .*.cmd file.
When the compiler is updated, syncconfig is invoked because init/Kconfig
contains the reference to the environment variable CC_VERTION_TEXT.
CONFIG_CC_VERSION_TEXT is updated to the new version string, and
include/config/cc/version/text.h is touched.
In the next rebuild, Make will rebuild every files since the timestamp
of include/config/cc/version/text.h is newer than that of target.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_KCONFIG_H
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#define __LINUX_KCONFIG_H
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/* CONFIG_CC_VERSION_TEXT (Do not delete this comment. See help in Kconfig) */
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#include <generated/autoconf.h>
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define __BIG_ENDIAN 4321
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#else
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#define __LITTLE_ENDIAN 1234
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#endif
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#define __ARG_PLACEHOLDER_1 0,
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#define __take_second_arg(__ignored, val, ...) val
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/*
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* The use of "&&" / "||" is limited in certain expressions.
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* The following enable to calculate "and" / "or" with macro expansion only.
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*/
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#define __and(x, y) ___and(x, y)
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#define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y)
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#define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0)
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#define __or(x, y) ___or(x, y)
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#define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y)
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#define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y)
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/*
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* Helper macros to use CONFIG_ options in C/CPP expressions. Note that
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* these only work with boolean and tristate options.
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*/
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/*
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* Getting something that works in C and CPP for an arg that may or may
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* not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1"
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* we match on the placeholder define, insert the "0," for arg1 and generate
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* the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one).
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* When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
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* the last step cherry picks the 2nd arg, we get a zero.
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*/
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#define __is_defined(x) ___is_defined(x)
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#define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val)
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#define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0)
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/*
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* IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
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* otherwise. For boolean options, this is equivalent to
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* IS_ENABLED(CONFIG_FOO).
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*/
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#define IS_BUILTIN(option) __is_defined(option)
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/*
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* IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
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* otherwise.
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*/
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#define IS_MODULE(option) __is_defined(option##_MODULE)
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/*
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* IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled
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* code can call a function defined in code compiled based on CONFIG_FOO.
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* This is similar to IS_ENABLED(), but returns false when invoked from
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* built-in code when CONFIG_FOO is set to 'm'.
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*/
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#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
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__and(IS_MODULE(option), __is_defined(MODULE)))
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/*
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* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
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* 0 otherwise.
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*/
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#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
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#endif /* __LINUX_KCONFIG_H */
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