Re: [PATCH] ARM: crypto: comment out gcc warning that breaks clang builds

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sun, Jul 31, 2022 at 01:13:14PM +0200, Ard Biesheuvel wrote:
> On Sun, 31 Jul 2022 at 12:39, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, Jul 31, 2022 at 12:17:40PM +0200, Ard Biesheuvel wrote:
> > > On Sun, 31 Jul 2022 at 12:05, Greg Kroah-Hartman
> > > <gregkh@linuxfoundation.org> wrote:
> > > >
> > > > From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > >
> > > > The gcc build warning prevents all clang-built kernels from working
> > > > properly, so comment it out to fix the build.
> > > >
> > > > This is a -stable kernel only patch for now, it will be resolved
> > > > differently in mainline releases in the future.
> > > >
> > > > Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
> > > > Cc: "Justin M. Forbes" <jforbes@fedoraproject.org>
> > > > Cc: Ard Biesheuvel <ardb@kernel.org>
> > > > Cc: Arnd Bergmann <arnd@kernel.org>
> > > > Cc: Nicolas Pitre <nico@linaro.org>
> > > > Cc: Nathan Chancellor <nathan@kernel.org>
> > > > Cc: Nick Desaulniers <ndesaulniers@google.com>
> > > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > ---
> > > >  arch/arm/lib/xor-neon.c | 3 ++-
> > > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/arch/arm/lib/xor-neon.c b/arch/arm/lib/xor-neon.c
> > > > index b99dd8e1c93f..7ba6cf826162 100644
> > > > --- a/arch/arm/lib/xor-neon.c
> > > > +++ b/arch/arm/lib/xor-neon.c
> > > > @@ -26,8 +26,9 @@ MODULE_LICENSE("GPL");
> > > >   * While older versions of GCC do not generate incorrect code, they fail to
> > > >   * recognize the parallel nature of these functions, and emit plain ARM code,
> > > >   * which is known to be slower than the optimized ARM code in asm-arm/xor.h.
> > > > + *
> > > > + * #warning This code requires at least version 4.6 of GCC
> > > >   */
> > > > -#warning This code requires at least version 4.6 of GCC
> > > >  #endif
> > > >
> > > >  #pragma GCC diagnostic ignored "-Wunused-variable"
> > >
> > > LGTM but doesn't Clang also complain about the GCC specific pragma?
> >
> > I don't know, all clang builds always failed at the first #warning line :)
> 
> Just tried it, and it appears to ignore the #pragma so we're all good.

Wonderful, thanks for testing.

greg k-h