On Fri, 2023-06-23 at 09:39 -0700, Nick Desaulniers wrote: > On Fri, Jun 23, 2023 at 6:44 AM WANG Xuerui <kernel@xxxxxxxxxx> wrote: > > > > From: WANG Xuerui <git@xxxxxxxxxx> > > > > Now the arch code is mostly ready for LLVM/Clang consumption, it is time > > to re-organize the CFLAGS a little to actually enable the LLVM build. > > > > A build with !RELOCATABLE && !MODULE is confirmed working within a QEMU > > environment; support for the two features are currently blocked by > > LLVM/Clang, and will come later. > > > > Signed-off-by: WANG Xuerui <git@xxxxxxxxxx> > > --- > > arch/loongarch/Makefile | 14 +++++++++++--- > > arch/loongarch/vdso/Makefile | 6 +++++- > > 2 files changed, 16 insertions(+), 4 deletions(-) > > > > diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile > > index a27e264bdaa5..efe9b50bd829 100644 > > --- a/arch/loongarch/Makefile > > +++ b/arch/loongarch/Makefile > > @@ -46,12 +46,18 @@ ld-emul = $(64bit-emul) > > cflags-y += -mabi=lp64s > > endif > > > > -cflags-y += -G0 -pipe -msoft-float > > This seems to drop -msoft-float for GCC. Intentional? > > > -LDFLAGS_vmlinux += -G0 -static -n -nostdlib > > +ifndef CONFIG_CC_IS_CLANG > > +cflags-y += -G0 > > +LDFLAGS_vmlinux += -G0 > > Thanks for the patch! > > I can understand not passing -G0 to clang if clang doesn't understand > it, but should you be using CONFIG_LD_IS_LLD for LDFLAGS? > > What does -G0 do? -G0 is a no-op for now because there is no small bss/data optimization implemented for LoongArch yet. /* snip */ > Why would AS_HAS_EXPLICIT_RELOCS be set if -mexplicit-relocs isn't > supported? Is the kconfig for that broken? Using GCC 12 (w/o -mexplicit-relocs support) together with Binutils >= 2.39 (with explicit relocs support) will cause kernel modules fail to be loaded (because there will be R_LARCH_ABS_* relocations in the modules and the module loader does not support them), so we deliberately reject such a combination at compile time. I could add R_LARCH_ABS_* implementation into the module loader to make it work, but Huacai suggested to just declare the combination of GCC 12 and Binutils >= 2.39 unsupported. -- Xi Ruoyao <xry111@xxxxxxxxxxx> School of Aerospace Science and Technology, Xidian University
