On Thu, 2024-07-18 at 10:34 -0700, Fangrui Song wrote:
> glibc added support for .gnu.hash in 2006 and .hash has been obsoleted
> for more than one decade in many Linux distributions. Using
> --hash-style=sysv might imply unaddressed issues and confuse readers.
>
> Just drop the option and rely on the linker default, which is likely
> "both", or "gnu" when the distribution really wants to eliminate sysv
> hash overhead.
>
> Similar to commit 6b7e26547fad ("x86/vdso: Emit a GNU hash").
>
> Signed-off-by: Fangrui Song <maskray@xxxxxxxxxx>
Hi Fangrui,
If I read tools/testing/selftests/vDSO/parse_vdso.c correctly, it does
know DT_GNU_HASH as at now. Thus after this change the vDSO selftests
are skipped with "Couldn't find __vdso_gettimeofday" etc if the distro
enables --hash-style=gnu by default.
So it seems we need to add DT_GNU_HASH support for parse_vdso.c to keep
test coverage.
> ---
> arch/arm64/kernel/vdso/Makefile | 2 +-
> arch/arm64/kernel/vdso32/Makefile | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
> index d63930c82839..d11da6461278 100644
> --- a/arch/arm64/kernel/vdso/Makefile
> +++ b/arch/arm64/kernel/vdso/Makefile
> @@ -21,7 +21,7 @@ btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
> # potential future proofing if we end up with internal calls to the exported
> # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
> # preparation in build-time C")).
> -ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv \
> +ldflags-y := -shared -soname=linux-vdso.so.1 \
> -Bsymbolic --build-id=sha1 -n $(btildflags-y)
>
> ifdef CONFIG_LD_ORPHAN_WARN
> diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
> index cc4508c604b2..25a2cb6317f3 100644
> --- a/arch/arm64/kernel/vdso32/Makefile
> +++ b/arch/arm64/kernel/vdso32/Makefile
> @@ -98,7 +98,7 @@ VDSO_AFLAGS += -D__ASSEMBLY__
> # From arm vDSO Makefile
> VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1
> VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096
> -VDSO_LDFLAGS += -shared --hash-style=sysv --build-id=sha1
> +VDSO_LDFLAGS += -shared --build-id=sha1
> VDSO_LDFLAGS += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
>
>
--
Xi Ruoyao <xry111@xxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University
