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| author | Robert Elliott <elliott@hpe.com> | 2022-08-27 14:38:36 -0500 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2022-09-27 13:21:44 -0600 |
| commit | 3832d1fd84b6220842d92513239005b2c116633b (patch) | |
| tree | 9945bae34f699f8f992fa17743d31cdb3c71e665 /Documentation | |
| parent | e2815b71cc48c988474dc2f2fc4725c5913f7155 (diff) | |
| download | lwn-3832d1fd84b6220842d92513239005b2c116633b.tar.gz lwn-3832d1fd84b6220842d92513239005b2c116633b.zip | |
docs/core-api: expand Fedora instructions for GCC plugins
In Fedora 36, cross-compiling an allmodconfig configuration
for other architectures on x86 fails with this problem:
In file included from ../scripts/gcc-plugins/gcc-common.h:95,
from ../scripts/gcc-plugins/latent_entropy_plugin.c:78:
/usr/lib/gcc/aarch64-linux-gnu/12/plugin/include/builtins.h:23:10: fatal
error: mpc.h: No such file or directory
23 | #include <mpc.h>
| ^~~~~~~
compilation terminated.
In that distro, that header file is available in the separate
libmpc-devel package.
Although future versions of Fedora might correctly mark
that dependency, mention this additional package.
To help detect such problems ahead of time, describe the
gcc -print-file-name=plugin
command that is used by scripts/gcc-plugins/Kconfig to detect
plugins [1].
[1] https://lore.kernel.org/lkml/CAHk-=wjjiYjCp61gdAMpDOsUBU-A2hFFKJoVx5VAC7yV4K6WYg@xxxxxxxxxxxxxx/
Fixes: 43e96ef8b70c50f ("docs/core-api: Add Fedora instructions for GCC plugins");
Signed-off-by: Robert Elliott <elliott@hpe.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220827193836.2582079-1-elliott@hpe.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kbuild/gcc-plugins.rst | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst index 0ba76719f1b9..c578c6ba3eb6 100644 --- a/Documentation/kbuild/gcc-plugins.rst +++ b/Documentation/kbuild/gcc-plugins.rst @@ -90,7 +90,11 @@ e.g., on Ubuntu for gcc-10:: Or on Fedora:: - dnf install gcc-plugin-devel + dnf install gcc-plugin-devel libmpc-devel + +Or on Fedora when using cross-compilers that include plugins:: + + dnf install libmpc-devel Enable the GCC plugin infrastructure and some plugin(s) you want to use in the kernel config:: @@ -99,6 +103,19 @@ in the kernel config:: CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y ... +Run gcc (native or cross-compiler) to ensure plugin headers are detected:: + + gcc -print-file-name=plugin + CROSS_COMPILE=arm-linux-gnu- ${CROSS_COMPILE}gcc -print-file-name=plugin + +The word "plugin" means they are not detected:: + + plugin + +A full path means they are detected:: + + /usr/lib/gcc/x86_64-redhat-linux/12/plugin + To compile the minimum tool set including the plugin(s):: make scripts |