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Linux kernel source tree for SHARP Brain series (PW-SH1 or later)
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Nathan Chancellor 589834b3a0 kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS 
In commit ebcc5928c5 ("arm64: Silence gcc warnings about arch ABI
drift"), the arm64 Makefile added -Wno-psabi to KBUILD_CFLAGS, which is
a GCC only option so clang rightfully complains:

warning: unknown warning option '-Wno-psabi' [-Wunknown-warning-option]

https://clang.llvm.org/docs/DiagnosticsReference.html#wunknown-warning-option

However, by default, this is merely a warning so the build happily goes
on with a slew of these warnings in the process.

Commit c3f0d0bc5b ("kbuild, LLVMLinux: Add -Werror to cc-option to
support clang") worked around this behavior in cc-option by adding
-Werror so that unknown flags cause an error. However, this all happens
silently and when an unknown flag is added to the build unconditionally
like -Wno-psabi, cc-option will always fail because there is always an
unknown flag in the list of flags. This manifested as link time failures
in the arm64 libstub because -fno-stack-protector didn't get added to
KBUILD_CFLAGS.

To avoid these weird cryptic failures in the future, make clang behave
like gcc and immediately error when it encounters an unknown flag by
adding -Werror=unknown-warning-option to CLANG_FLAGS. This can be added
unconditionally for clang because it is supported by at least 3.0.0,
according to godbolt [1] and 4.0.0, according to its documentation [2],
which is far earlier than we typically support.

[1]: https://godbolt.org/z/7F7rm3
[2]: https://releases.llvm.org/4.0.0/tools/clang/docs/DiagnosticsReference.html#wunknown-warning-option

Link: https://github.com/ClangBuiltLinux/linux/issues/511
Link: https://github.com/ClangBuiltLinux/linux/issues/517
Suggested-by: Peter Smith <peter.smith@linaro.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-24 03:43:03 +09:00
arch kbuild: add CONFIG_HEADERS_INSTALL and loosen the dependency of samples 2019-06-15 19:57:01 +09:00
block block, bfq: add weight symlink to the bfq.weight cgroup parameter 2019-06-07 01:29:40 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
Documentation kbuild: add support for ensuring headers are self-contained 2019-06-15 19:57:02 +09:00
drivers kbuild: add support for ensuring headers are self-contained 2019-06-15 19:57:02 +09:00
fs A change to call iput() asynchronously to avoid a possible deadlock 2019-06-08 15:57:35 -07:00
include kbuild: re-implement Makefile.headersinst without recursion 2019-06-15 19:57:02 +09:00
init kbuild: add support for ensuring headers are self-contained 2019-06-15 19:57:02 +09:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
kernel SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
lib kbuild: add 'headers' target to build up uapi headers in usr/include 2019-06-15 19:57:02 +09:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
net SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
samples kbuild: add CONFIG_HEADERS_INSTALL and loosen the dependency of samples 2019-06-15 19:57:01 +09:00
scripts kbuild: add support for ensuring headers are self-contained 2019-06-15 19:57:02 +09:00
security treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
sound treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
tools SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: add support for ensuring headers are self-contained 2019-06-15 19:57:02 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Farewell Martin Schwidefsky 2019-05-31 10:14:11 +02:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-06-08 12:48:49 -07:00
Makefile kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS 2019-06-24 03:43:03 +09:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.