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    SubjectRe: [PATCH] kbuild: Always link with '-z norelro'
    On Thu, Nov 12, 2020 at 11:38:40AM -0700, Nathan Chancellor wrote:
    > Commit 3bbd3db86470 ("arm64: relocatable: fix inconsistencies in linker
    > script and options") added '-z norelro' to the arm64 Makefile when
    > CONFIG_RELOCATABLE was set to help support ld.lld because ld.lld
    > defaults to '-z relro' but the kernel does not use program headers or
    > adhere to the section layout that is required for RELRO to work.
    >
    > Commit 3b92fa7485eb ("arm64: link with -z norelro regardless of
    > CONFIG_RELOCATABLE") unconditionally added it to LDFLAGS_vmlinux because
    > an error occurs with CONFIG_KASAN set even when CONFIG_RELOCATABLE is
    > unset.
    >
    > As it turns out, ARM experiences the same error after CONFIG_KASAN was
    > implemented, meaning that '-z norelro' needs to be added to that
    > Makefile as well (multi_v7_defconfig + CONFIG_KASAN=y + LD=ld.lld):
    >
    > $ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 zImage
    > ld.lld: error: section: .exit.data is not contiguous with other relro sections
    >
    > To avoid playing whack-a-mole with different architectures over time,
    > hoist '-z norelro' into the main Makefile. This does not affect ld.bfd
    > because '-z norelro' is the default for it.
    >
    > Link: https://github.com/ClangBuiltLinux/linux/issues/1189
    > Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
    > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
    > ---
    >
    > Hi all,
    >
    > This should probably go into Russell's tree with acks from the arm64 and
    > kbuild maintainers.

    So that's a fix for arch/arm going in the top Makefile.

    For the arm64 part:

    Acked-by: Catalin Marinas <catalin.marinas@arm.com>

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