Re: [PATCH 17/22] arm64: vdso: disable LTO

Nick Desaulniers
2020-06-24T20:59:11Z

On Wed, Jun 24, 2020 at 1:33 PM Sami Tolvanen <samitolvanen@google.com> wrote:
>
> Filter out CC_FLAGS_LTO for the vDSO.

Just curious about this patch (and the following one for x86's vdso),
do you happen to recall specifically what the issues with the vdso's
are?

>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> ---
> arch/arm64/kernel/vdso/Makefile | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
> index 556d424c6f52..cfad4c296ca1 100644
> --- a/arch/arm64/kernel/vdso/Makefile
> +++ b/arch/arm64/kernel/vdso/Makefile
> @@ -29,8 +29,8 @@ ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
> ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
> ccflags-y += -DDISABLE_BRANCH_PROFILING
>
> -CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS)
> -KBUILD_CFLAGS += $(DISABLE_LTO)
> +CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
> + $(CC_FLAGS_LTO)
> KASAN_SANITIZE := n
> UBSAN_SANITIZE := n
> OBJECT_FILES_NON_STANDARD := y
> --
> 2.27.0.212.ge8ba1cc988-goog
>

--
Thanks,
~Nick Desaulniers