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'

Discard the new sections in the necessary linker scripts to resolve the
warnings, as the kernel and vDSO do not need to retain it, similar to
the .note.gnu.property section.

Cc: stable@vger.kernel.org
Fixes: b3e5d80d0c48 ("arm64/build: Warn on orphan section placement")
Link: https://github.com/llvm/llvm-project/commit/ee99c4d4845db66c4daa2373352133f4b237c942 [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
Changes in v3:
- Update location of section discard in vDSO to align with
  .note.gnu.property discard since the sectionss are similar in
  nature (Will).
- Link to v2: https://lore.kernel.org/r/20250204-arm64-handle-arm-attributes-in-linker-script-v2-1-d684097f5554@kernel.org

Changes in v2:
- Discard the section instead of adding it to the final artifacts to
  mirror the .note.gnu.property section handling (Will).
- Link to v1: https://lore.kernel.org/r/20250124-arm64-handle-arm-attributes-in-linker-script-v1-1-74135b6cf349@kernel.org
---
 arch/arm64/kernel/vdso/vdso.lds.S | 1 +
 arch/arm64/kernel/vmlinux.lds.S   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
index 4ec32e86a8da..47ad6944f9f0 100644
--- a/arch/arm64/kernel/vdso/vdso.lds.S
+++ b/arch/arm64/kernel/vdso/vdso.lds.S
@@ -41,6 +41,7 @@ SECTIONS
 	 */
 	/DISCARD/	: {
 		*(.note.GNU-stack .note.gnu.property)
+		*(.ARM.attributes)
 	}
 	.note		: { *(.note.*) }		:text	:note
 
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index f84c71f04d9e..e73326bd3ff7 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -162,6 +162,7 @@ SECTIONS
 	/DISCARD/ : {
 		*(.interp .dynamic)
 		*(.dynsym .dynstr .hash .gnu.hash)
+		*(.ARM.attributes)
 	}
 
 	. = KIMAGE_VADDR;

---
base-commit: 1dd3393696efba1598aa7692939bba99d0cffae3
change-id: 20250123-arm64-handle-arm-attributes-in-linker-script-82aee25313ac

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>

On Thu, 06 Feb 2025 10:21:38 -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'
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: Handle .ARM.attributes section in linker scripts
      https://git.kernel.org/arm64/c/ca0f4fe7cf71

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev