On Wed, 22 May 2024 at 19:32, Nathan Chancellor <nathan@xxxxxxxxxx> wrote: > > When building ARCH=loongarch defconfig + CONFIG_UNWINDER_ORC=y using > LLVM, there is a warning from ld.lld when linking the EFI zboot image > due to the use of unreachable() in number() in vsprintf.c: > > ld.lld: warning: drivers/firmware/efi/libstub/lib.a(vsprintf.stub.o):(.discard.unreachable+0x0): has non-ABS relocation R_LARCH_32_PCREL against symbol '' > > If the compiler cannot eliminate the default case for any reason, the > .discard.unreachable section will remain in the final binary but the > entire point of any section prefixed with .discard is that it is only > used at compile time, so it can be discarded via /DISCARD/ in a linker > script. The asm-generic vmlinux.lds.h includes .discard and .discard.* > in the COMMON_DISCARDS macro but that is not used for zboot.lds, as it > is not a kernel image linker script. > > Add .discard and .discard.* to /DISCARD/ in zboot.lds, so that any > sections meant to be discarded at link time are not included in the > final zboot image. This issue is not specific to LoongArch, it is just > the first architecture to select CONFIG_OBJTOOL, which defines > annotate_unreachable() as an asm statement to add the > .discard.unreachable section, and use the EFI stub. > > Closes: https://github.com/ClangBuiltLinux/linux/issues/2023 > Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> Thanks, I'll take this as a fix. > --- > drivers/firmware/efi/libstub/zboot.lds | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/firmware/efi/libstub/zboot.lds b/drivers/firmware/efi/libstub/zboot.lds > index ac8c0ef85158..af2c82f7bd90 100644 > --- a/drivers/firmware/efi/libstub/zboot.lds > +++ b/drivers/firmware/efi/libstub/zboot.lds > @@ -41,6 +41,7 @@ SECTIONS > } > > /DISCARD/ : { > + *(.discard .discard.*) > *(.modinfo .init.modinfo) > } > } > > --- > base-commit: 15aa8fb852f995dd234a57f12dfb989044968bb6 > change-id: 20240522-efi-zboot-lds-add-discard-sections-to-discard-5fe29bf42d6a > > Best regards, > -- > Nathan Chancellor <nathan@xxxxxxxxxx> >
