On Fri, Jan 24, 2025 at 06:31:57AM -0700, Nathan Chancellor wrote:

A recent LLVM commit [1] started generating an .ARM.attributes section similar to the one that exists for 32-bit, which results in orphan section warnings (or errors if CONFIG_WERROR is enabled) from the linker because it is not handled in the arm64 linker scripts.

ld.lld: error: arch/arm64/kernel/vdso/vgettimeofday.o:(.ARM.attributes) is being placed in '.ARM.attributes' ld.lld: error: arch/arm64/kernel/vdso/vgetrandom.o:(.ARM.attributes) is being placed in '.ARM.attributes'

ld.lld: error: vmlinux.a(lib/vsprintf.o):(.ARM.attributes) is being placed in '.ARM.attributes' ld.lld: error: vmlinux.a(lib/win_minmax.o):(.ARM.attributes) is being placed in '.ARM.attributes' ld.lld: error: vmlinux.a(lib/xarray.o):(.ARM.attributes) is being placed in '.ARM.attributes'

Add this new section to the necessary linker scripts to resolve the warnings.

Cc: stable@vger.kernel.org Fixes: b3e5d80d0c48 ("arm64/build: Warn on orphan section placement") Link: https://github.com/llvm/llvm-project/commit/ee99c4d4845db66c4daa2373352133f4... [1] Signed-off-by: Nathan Chancellor nathan@kernel.org

---

arch/arm64/kernel/vdso/vdso.lds.S | 1 + arch/arm64/kernel/vmlinux.lds.S | 1 + 2 files changed, 2 insertions(+)

Hmm. I wonder what this new attributes section is for and how it will co-exist with .note.gnu.property in future? For example, the spec linked form the above commit:

https://github.com/ARM-software/abi-aa/pull/230

has references to GCS, which I don't think has a corresponding feature bit for the ELF note (at least, Linux doesn't know about it if it does).

diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S index 4ec32e86a8da..f8418a3a2758 100644 --- a/arch/arm64/kernel/vdso/vdso.lds.S +++ b/arch/arm64/kernel/vdso/vdso.lds.S @@ -75,6 +75,7 @@ SECTIONS DWARF_DEBUG ELF_DETAILS

• .ARM.attributes 0 : { *(.ARM.attributes) }

Let's just add this to the /DISCARD/ section higher up, where we chuck away .note.gnu.property.

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index f84c71f04d9e..c94942e9eb46 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -335,6 +335,7 @@ SECTIONS STABS_DEBUG DWARF_DEBUG ELF_DETAILS

• .ARM.attributes 0 : { *(.ARM.attributes) }

I think we should discard this too (afaict, RO_DATA() discards .note.gnu.property via NOTES()).

Will