Re: [PATCH 10/12] efi/libstub: Remove obsolete .note.gnu.property workaround

[Nick Desaulniers]

On Fri, Aug 14, 2026 at 9:45 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
>
> Commit e2179a09ab08 ("efi/libstub: Disable -mbranch-protection") added
> --remove-section=.note.gnu.property to the stub objcopy invocation to
> work around a Clang bug where the note was emitted for code-less object
> files even with -mbranch-protection=none.
>
> That was fixed by LLVM commit a48f6079f288 ("[AArch64] Generate
> .note.gnu.property based on module flags") which was released with
> Clang 12.  The minimum Clang version is now Clang 17, so this workaround
> is no longer needed.
>
> On arm64, the stub also no longer builds with -mbranch-protection=none,
> as it has inherited the kernel's flags since commit 8358098b9787
> ("arm64: efi: Enable BTI codegen and add PE/COFF annotation").

I verified the above all looks correct.  Thanks for the cleanup.
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>

>
> Remove the workaround.  This fixes BTI on arm64, and is a no-op on
> RISC-V and LoongArch where the vmlinux generic NOTES macro discards it,
> and the x86 and ARM decompressors discard .note.* explicitly.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> ---
>  drivers/firmware/efi/libstub/Makefile | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index b1c95f69e807d..e18e124a89acf 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -106,12 +106,6 @@ lib-$(CONFIG_UNACCEPTED_MEMORY) += unaccepted_memory.o bitmap.o find.o
>  targets                                := $(lib-y)
>  lib-y                          := $(patsubst %.o,%.stub.o,$(lib-y))
>
> -# Even when -mbranch-protection=none is set, Clang will generate a
> -# .note.gnu.property for code-less object files (like lib/ctype.c),
> -# so work around this by explicitly removing the unwanted section.
> -# https://llvm.org/pr46480
> -STUBCOPY_FLAGS-y               += --remove-section=.note.gnu.property
> -
>  STUBCOPY_RELOC-$(CONFIG_X86_32)        := R_386_32
>  STUBCOPY_RELOC-$(CONFIG_X86_64)        := R_X86_64_64
>
> --
> 2.55.0
>


-- 
Thanks,
~Nick Desaulniers