[PATCH] ARM: Link with '-z norelro'

[Nick Desaulniers]

On Mon, Nov 9, 2020 at 6:05 PM Nick Desaulniers <ndesaulniers at google.com> wrote:
>
> On Mon, Nov 9, 2020 at 5:56 PM Nathan Chancellor
> <natechancellor at gmail.com> wrote:
> >
> > When linking a multi_v7_defconfig + CONFIG_KASAN=y kernel with
> > LD=ld.lld, the following error occurs:
> >
> > $ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 zImage
> > ld.lld: error: section: .exit.data is not contiguous with other relro sections
> >
> > LLD defaults to '-z relro', which is unneeded for the kernel because
> > program headers are not used nor is there any position independent code
> > generation or linking for ARM. Add '-z norelro' to LDFLAGS_vmlinux to
> > avoid this error.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1189
> > Signed-off-by: Nathan Chancellor <natechancellor at gmail.com>
>
> Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>
> Tested-by: Nick Desaulniers <ndesaulniers at google.com>
>
> Thanks for the patch!
> See also: https://lore.kernel.org/linux-arm-kernel/20201016175339.2429280-1-ndesaulniers@google.com/
> where we just did the same thing for aarch64.

I was thinking more about this last night.  If we're going to be
playing whack-a-mole for each architecture with this, would it be
worthwhile for us to raise this up to the top level Makefile?
-- 
Thanks,
~Nick Desaulniers