On Tue, Feb 13, 2024 at 11:47:04AM +0100, Sumanth Korikkar wrote: > Gcc recently implemented an optimization [1] for loading symbols without > explicit alignment, aligning with the IBM Z ELF ABI. This ABI mandates > symbols to reside on a 2-byte boundary, enabling the use of the larl > instruction. However, kernel linker scripts may still generate unaligned > symbols. To address this, a new -munaligned-symbols option has been > introduced [2] in recent gcc versions. > > [1] https://gcc.gnu.org/pipermail/gcc-patches/2023-June/622872.html > [2] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/625986.html > > However, when -munaligned-symbols is used in vdso code, it leads to the > following compilation error: > `.data.rel.ro.local' referenced in section `.text' of > arch/s390/kernel/vdso64/vdso64_generic.o: defined in discarded section > `.data.rel.ro.local' of arch/s390/kernel/vdso64/vdso64_generic.o > > vdso linker script discards .data section to make it lightweight. > However, -munaligned-symbols in vdso object files references literal > pool and accesses _vdso_data. Hence, compile vdso code without > -munaligned-symbols. This means in the future, vdso code should deal > with alignment of newly introduced unaligned linker symbols. > > Signed-off-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx> > --- > arch/s390/kernel/vdso64/Makefile | 1 + > 1 file changed, 1 insertion(+) Acked-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
