| Message ID | 20220529152200.609809-1-ben.dooks@codethink.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] riscv: add as-options for modules with assembly compontents | expand |
On Sun, 29 May 2022 08:22:00 PDT (-0700), ben.dooks@codethink.co.uk wrote: > 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/3b0a7d624e64eeb81e4d5e8c62c46d86ef521857 > > Notes: > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > Reviewed-by: Bin Meng <bmeng.cn@gmail.com> > --- > arch/riscv/Makefile | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > index 1f5c03082976..fca40511a8c6 100644 > --- a/arch/riscv/Makefile > +++ b/arch/riscv/Makefile > @@ -60,6 +60,7 @@ 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 Sorry for being so slow here, I've gotten pretty buried and it wasn't clear this was a fix. I put it in fixes with some tags. Thanks!
On 21/07/2022 20:53, Palmer Dabbelt wrote: > On Sun, 29 May 2022 08:22:00 PDT (-0700), ben.dooks@codethink.co.uk wrote: [nip >> # GCC versions that support the "-mstrict-align" option default to >> allowing >> # unaligned accesses. While unaligned accesses are explicitly >> allowed in the > > Sorry for being so slow here, I've gotten pretty buried and it wasn't > clear this was a fix. I put it in fixes with some tags. Is it time for linux-riscv list to have a patch tracker on? This might help with tracking patches for everyone.
On 25/07/2022 12:38, Ben Dooks wrote: > On 21/07/2022 20:53, Palmer Dabbelt wrote: >> On Sun, 29 May 2022 08:22:00 PDT (-0700), ben.dooks@codethink.co.uk wrote: > > [nip > >>> # GCC versions that support the "-mstrict-align" option default to allowing >>> # unaligned accesses. While unaligned accesses are explicitly allowed in the >> >> Sorry for being so slow here, I've gotten pretty buried and it wasn't clear this was a fix. I put it in fixes with some tags. > > Is it time for linux-riscv list to have a patch tracker on? This might > help with tracking patches for everyone. https://patchwork.kernel.org/project/linux-riscv/list/ Just isn't used at all from what I can see.
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 1f5c03082976..fca40511a8c6 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -60,6 +60,7 @@ 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
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/3b0a7d624e64eeb81e4d5e8c62c46d86ef521857 Notes: Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> --- arch/riscv/Makefile | 1 + 1 file changed, 1 insertion(+)