+ (folks recommended by ./scripts/get_maintainer.pl <patchfile>)
(See also, step 7:
https://nickdesaulniers.github.io/blog/2017/05/16/submitting-your-first-patch-to-the-linux-kernel-and-responding-to-feedback/)
On Wed, Sep 4, 2019 at 2:45 PM Steve Wahl <steve.w...@hpe.com> wrote:
>
> The last change to this Makefile caused relocation errors when loading
It's good to add a fixes tag like below when a patch fixes a
regression, so that stable backports the fix as far back as the
regression:
Fixes: b059f801a937 ("x86/purgatory: Use CFLAGS_REMOVE rather than
reset KBUILD_CFLAGS")
> a kdump kernel. This change restores the appropriate flags, without
> reverting to the former practice of resetting KBUILD_CFLAGS.
>
> Signed-off-by: Steve Wahl <steve.w...@hpe.com>
> ---
> arch/x86/purgatory/Makefile | 35 +++++++++++++++++++----------------
> 1 file changed, 19 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 8901a1f89cf5..9f0bfef1f5db 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -18,37 +18,40 @@ targets += purgatory.ro
> KASAN_SANITIZE := n
> KCOV_INSTRUMENT := n
>
> +# These are adjustments to the compiler flags used for objects that
> +# make up the standalone porgatory.ro
> +
> +PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
> +PURGATORY_CFLAGS := -mcmodel=large -ffreestanding
> -fno-zero-initialized-in-bss
Thanks for confirming the fix. While it sounds like -mcmodel=large is
the only necessary change, I don't object to -ffreestanding of
-fno-zero-initialized-in-bss being readded, especially since I think
what you've done with PURGATORY_CFLAGS_REMOVE is more concise.
Reviewed-by: Nick Desaulniers <ndesaulni...@google.com>
Vaibhav, do you still have an environment setup to quickly test this
again w/ Clang builds?
Tglx, we'll likely want to get this into 5.3 if it's not too late (I
saw Miguel Ojeda mention there might be an -rc8)?
> +
> # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
> # in turn leaves some undefined symbols like __fentry__ in purgatory and not
> # sure how to relocate those.
> ifdef CONFIG_FUNCTION_TRACER
> -CFLAGS_REMOVE_sha256.o += $(CC_FLAGS_FTRACE)
> -CFLAGS_REMOVE_purgatory.o += $(CC_FLAGS_FTRACE)
> -CFLAGS_REMOVE_string.o += $(CC_FLAGS_FTRACE)
> -CFLAGS_REMOVE_kexec-purgatory.o += $(CC_FLAGS_FTRACE)
> +PURGATORY_CFLAGS_REMOVE += $(CC_FLAGS_FTRACE)
> endif
>
> ifdef CONFIG_STACKPROTECTOR
> -CFLAGS_REMOVE_sha256.o += -fstack-protector
> -CFLAGS_REMOVE_purgatory.o += -fstack-protector
> -CFLAGS_REMOVE_string.o += -fstack-protector
> -CFLAGS_REMOVE_kexec-purgatory.o += -fstack-protector
> +PURGATORY_CFLAGS_REMOVE += -fstack-protector
> endif
>
> ifdef CONFIG_STACKPROTECTOR_STRONG
> -CFLAGS_REMOVE_sha256.o += -fstack-protector-strong
> -CFLAGS_REMOVE_purgatory.o += -fstack-protector-strong
> -CFLAGS_REMOVE_string.o += -fstack-protector-strong
> -CFLAGS_REMOVE_kexec-purgatory.o += -fstack-protector-strong
> +PURGATORY_CFLAGS_REMOVE += -fstack-protector-strong
> endif
>
> ifdef CONFIG_RETPOLINE
> -CFLAGS_REMOVE_sha256.o += $(RETPOLINE_CFLAGS)
> -CFLAGS_REMOVE_purgatory.o += $(RETPOLINE_CFLAGS)
> -CFLAGS_REMOVE_string.o += $(RETPOLINE_CFLAGS)
> -CFLAGS_REMOVE_kexec-purgatory.o += $(RETPOLINE_CFLAGS)
> +PURGATORY_CFLAGS_REMOVE += $(RETPOLINE_CFLAGS)
> endif
>
> +CFLAGS_REMOVE_purgatory.o += $(PURGATORY_CFLAGS_REMOVE)
> +CFLAGS_purgatory.o += $(PURGATORY_CFLAGS)
> +
> +CFLAGS_REMOVE_sha256.o += $(PURGATORY_CFLAGS_REMOVE)
> +CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
> +
> +CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
> +CFLAGS_string.o += $(PURGATORY_CFLAGS)
> +
> $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
> $(call if_changed,ld)
>
> --
> 2.12.3
>
--
Thanks,
~Nick Desaulniers
