With GNU binutils 2.35+, linking with BFD produces warnings for vmlinux:
aarch64-linux-gnu-ld: warning: -z norelro ignored
BFD can produce this warning when the target emulation mode does not
support RELRO program headers, and -z relro or -z norelro is passed.
Alan Modra clarifies:
The default linker emulation for an aarch64-linux ld.bfd is
-maarch64linux, the default for an aarch64-elf linker is
-maarch64elf. They are not equivalent. If you choose -maarch64elf
you get an emulation that doesn't support -z relro.
The ARCH=arm64 kernel prefers -maarch64elf, but may fall back to
-maarch64linux based on the toolchain configuration.
LLD will always create RELRO program header regardless of target
emulation.
To avoid the above warning when linking with BFD, pass -z norelro only
when linking with LLD or with -maarch64linux.
Fixes: 3b92fa7485 ("arm64: link with -z norelro regardless of CONFIG_RELOCATABLE")
Fixes: 3bbd3db864 ("arm64: relocatable: fix inconsistencies in linker script and options")
Cc: <stable@vger.kernel.org> # 5.0.x-
Reported-by: kernelci.org bot <bot@kernelci.org>
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alan Modra <amodra@gmail.com>
Cc: Fāng-ruì Sòng <maskray@google.com>
Link: https://lore.kernel.org/r/20201218002432.788499-1-ndesaulniers@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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