[kernel-hardening] Re: [PATCH v5 2/5] GCC plugin infrastructure

Emese Revfy
2016-03-27T21:09:13Z

On Sat, 26 Mar 2016 11:39:32 +0900
Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> > I tried to remove the gcc-plugins target but sadly in this case the plugins aren't complied.
> > I don't know if I understand how it should work. I pushed a commit:
> > https://github.com/ephox-gcc-plugins/gcc-plugins_linux-next/commit/0b005b886bde6c4b9134d01f830d88d464911a65
> > Could you please help me with what I did wrong?
> >
> Sorry, I missed this problem.
>
> GCC-plugins must be compiled before descending into ./Kbuild.
>
>
> Please apply the following on top of commit 0b005b88
> and check if it works.
>
> diff --git a/Makefile b/Makefile
> index 1c7a379..bd643d3 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1009,6 +1009,9 @@ archprepare: archheaders archscripts prepare1
> scripts_basic
> prepare0: KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS)
> prepare0: KBUILD_AFLAGS += $(GCC_PLUGINS_AFLAGS)
> prepare0: archprepare FORCE
> +ifdef CONFIG_GCC_PLUGINS
> + $(Q)$(MAKE) $(build)=scripts/gcc-plugins
> +endif
> $(Q)$(MAKE) $(build)=.
>
> # All the preparing..
> diff --git a/scripts/Makefile b/scripts/Makefile
> index 0ba652c..1d80897 100644
> --- a/scripts/Makefile
> +++ b/scripts/Makefile
> @@ -45,7 +45,6 @@ subdir-y += mod
> subdir-$(CONFIG_SECURITY_SELINUX) += selinux
> subdir-$(CONFIG_DTC) += dtc
> subdir-$(CONFIG_GDB_SCRIPTS) += gdb
> -subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins
>
> # Let clean descend into subdirs
> -subdir- += basic kconfig package
> +subdir- += basic kconfig package gcc-plugins

Thanks for the patch. I tested it and there is a problem when I run a parallel make.
The plugins are compiled later than needed (e.g., scripts/mod/empty.o). There is a lot of important
code under scripts/mod which may need the plugins. If the plugins were compiled when the "scripts_basic"
target runs it would be good but unfortunately the config symbol CONFIG_GCC_PLUGINS doesn't seem to be defined yet.
Could you please help me solve this problem?

--
Emese