aec6c60a01
Paul Gortmaker reported a regression in the GCC version check. [1] If you use GCC 4.8, the build breaks before showing the error message "error Sorry, your version of GCC is too old - please use 4.9 or newer." I do not want to apply his fix-up since it implies we would not be able to remove any cc-option test. Anyway, I admit checking the GCC version in <linux/compiler-gcc.h> is too late. Almost at the same time, Linus also suggested to move the compiler version error to Kconfig time. [2] I unified the two similar scripts, gcc-version.sh and clang-version.sh into cc-version.sh. The old scripts invoked the compiler multiple times (3 times for gcc-version.sh, 4 times for clang-version.sh). I refactored the code so the new one invokes the compiler just once, and also tried my best to use shell-builtin commands where possible. The new script runs faster. $ time ./scripts/clang-version.sh clang 120000 real 0m0.029s user 0m0.012s sys 0m0.021s $ time ./scripts/cc-version.sh clang Clang 120000 real 0m0.009s user 0m0.006s sys 0m0.004s cc-version.sh also shows an error message if the compiler is too old: $ make defconfig CC=clang-9 *** Default configuration is based on 'x86_64_defconfig' *** *** Compiler is too old. *** Your Clang version: 9.0.1 *** Minimum Clang version: 10.0.1 *** scripts/Kconfig.include:46: Sorry, this compiler is not supported. make[1]: *** [scripts/kconfig/Makefile:81: defconfig] Error 1 make: *** [Makefile:602: defconfig] Error 2 The new script takes care of ICC because we have <linux/compiler-intel.h> although I am not sure if building the kernel with ICC is well-supported. [1]: https://lore.kernel.org/r/20210110190807.134996-1-paul.gortmaker@windriver.com [2]: https://lore.kernel.org/r/CAHk-=wh-+TMHPTFo1qs-MYyK7tZh-OQovA=pP3=e06aCVp6_kA@mail.gmail.com Fixes: 87de84c9140e ("kbuild: remove cc-option test of -Werror=date-time") Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.