From: Ben Dooks ben.dooks@codethink.co.uk
commit c1f6eff304e4dfa4558b6a8c6b2d26a91db6c998 upstream.
When trying to load modules built for RISC-V which include assembly files the kernel loader errors with "unexpected relocation type 'R_RISCV_ALIGN'" due to R_RISCV_ALIGN relocations being generated by the assembler.
The R_RISCV_ALIGN relocations can be removed at the expense of code space by adding -mno-relax to gcc and as. In commit 7a8e7da42250138 ("RISC-V: Fixes to module loading") -mno-relax is added to the build variable KBUILD_CFLAGS_MODULE. See [1] for more info.
The issue is that when kbuild builds a .S file, it invokes gcc with the -mno-relax flag, but this is not being passed through to the assembler. Adding -Wa,-mno-relax to KBUILD_AFLAGS_MODULE ensures that the assembler is invoked correctly. This may have now been fixed in gcc[2] and this addition should not stop newer gcc and as from working.
[1] https://github.com/riscv/riscv-elf-psabi-doc/issues/183 [2] https://github.com/gcc-mirror/gcc/commit/3b0a7d624e64eeb81e4d5e8c62c46d86ef5...
Signed-off-by: Ben Dooks ben.dooks@codethink.co.uk Reviewed-by: Bin Meng bmeng.cn@gmail.com Link: https://lore.kernel.org/r/20220529152200.609809-1-ben.dooks@codethink.co.uk Fixes: ab1ef68e5401 ("RISC-V: Add sections of PLT and GOT for kernel module") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/Makefile | 1 + 1 file changed, 1 insertion(+)
--- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -74,6 +74,7 @@ ifeq ($(CONFIG_PERF_EVENTS),y) endif
KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax) +KBUILD_AFLAGS_MODULE += $(call as-option,-Wa$(comma)-mno-relax)
# GCC versions that support the "-mstrict-align" option default to allowing # unaligned accesses. While unaligned accesses are explicitly allowed in the