Re: [linux-stable-rc:linux-5.15.y 6874/8723] arch/arm/lib/xor-neon.c:30:2: warning: This code requires at least version 4.6 of GCC

Greg Kroah-Hartman
2022-07-30T14:33:31Z

On Mon, Jul 25, 2022 at 04:35:38PM +0200, Arnd Bergmann wrote:
> On Mon, Jul 25, 2022 at 2:55 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> > The other easy workaround would be to just turn off the xor-neon code
> > when building with clang, e.g. using this Makefile hack:
> >
> > diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
> > index 6d2ba454f25b..8e4fe6421dd2 100644
> > --- a/arch/arm/lib/Makefile
> > +++ b/arch/arm/lib/Makefile
> > @@ -43,8 +43,10 @@ endif
> > $(obj)/csumpartialcopy.o: $(obj)/csumpartialcopygeneric.S
> > $(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S
> >
> > +ifdef CONFIG_CC_IS_CLANG
> > ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
> > NEON_FLAGS := -march=armv7-a -mfloat-abi=softfp -mfpu=neon
> > CFLAGS_xor-neon.o += $(NEON_FLAGS)
> > obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o
> > endif
> > +endif
>
> Nevermind, this does not actually work. Just turning off the warning
> is probably best then, as actually disabling this code would still
> be invasive not do much beyond saving a little bit of kernel .text size.

Ok, if it triggers again, and I get annoyed, I'll write a patch,
otherwise I'll just leave it alone unless someone else wants to send it
to me...

thanks,

greg k-h