| Message ID | 20250124-arm64-handle-arm-attributes-in-linker-script-v1-1-74135b6cf349@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: Handle .ARM.attributes section in linker scripts | expand |
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/ee99c4d4845db66c4daa2373352133f4b237c942 [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
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) } /DISCARD/ : { *(.data .data.* .gnu.linkonce.d.* .sdata*) 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) } HEAD_SYMBOLS
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/ee99c4d4845db66c4daa2373352133f4b237c942 [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(+) --- base-commit: 1dd3393696efba1598aa7692939bba99d0cffae3 change-id: 20250123-arm64-handle-arm-attributes-in-linker-script-82aee25313ac Best regards,