Re: [tip:x86/core 1/1] arch/x86/um/../lib/csum-partial_64.c:98:12: error: implicit declaration of function 'load_unaligned_zeropad'

From: Johannes Berg <johannes@sipsolutions.net>
To: Peter Zijlstra <peterz@infradead.org>,
	Eric Dumazet <edumazet@google.com>
Cc: kernel test robot <lkp@intel.com>,
	kbuild-all@lists.01.org, linux-kernel@vger.kernel.org,
	x86@kernel.org, Alexander Duyck <alexanderduyck@fb.com>,
	linux-um@lists.infradead.org
Subject: Re: [tip:x86/core 1/1] arch/x86/um/../lib/csum-partial_64.c:98:12: error: implicit declaration of function 'load_unaligned_zeropad'
Date: Thu, 18 Nov 2021 17:26:51 +0100	[thread overview]
Message-ID: <21f86e2bc817b6ec0c7a9194a4fefb1d55e3040b.camel@sipsolutions.net> (raw)
In-Reply-To: <YZZ4upqWGMOY+r56@hirez.programming.kicks-ass.net>

On Thu, 2021-11-18 at 17:00 +0100, Peter Zijlstra wrote:
> On Wed, Nov 17, 2021 at 11:40:35AM -0800, Eric Dumazet wrote:
> > On Wed, Nov 17, 2021 at 10:55 AM Eric Dumazet <edumazet@google.com> wrote:
> > > 
> > > On Wed, Nov 17, 2021 at 10:46 AM kernel test robot <lkp@intel.com> wrote:
> > > > 
> > > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/core
> > > > head:   d31c3c683ee668ba5d87c0730610442fd672525f
> > > > commit: d31c3c683ee668ba5d87c0730610442fd672525f [1/1] x86/csum: Rewrite/optimize csum_partial()
> > > > config: um-x86_64_defconfig (attached as .config)
> > > > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> > > > reproduce (this is a W=1 build):
> > > >         # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=d31c3c683ee668ba5d87c0730610442fd672525f
> > > >         git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
> > > >         git fetch --no-tags tip x86/core
> > > >         git checkout d31c3c683ee668ba5d87c0730610442fd672525f
> > > >         # save the attached .config to linux build tree
> > > >         make W=1 ARCH=um SUBARCH=x86_64
> > > > 
> > > > If you fix the issue, kindly add following tag as appropriate
> > > > Reported-by: kernel test robot <lkp@intel.com>
> > > > 
> > > > All errors (new ones prefixed by >>):
> > > > 
> > > >    arch/x86/um/../lib/csum-partial_64.c: In function 'csum_partial':
> > > > > > arch/x86/um/../lib/csum-partial_64.c:98:12: error: implicit declaration of function 'load_unaligned_zeropad' [-Werror=implicit-function-declaration]
> > > >       98 |   trail = (load_unaligned_zeropad(buff) << shift) >> shift;
> > > >          |            ^~~~~~~~~~~~~~~~~~~~~~
> > > >    cc1: some warnings being treated as errors
> > > > 
> > > > 
> > > 
> > > Hmmm... it seems we need to guard this with CONFIG_DCACHE_WORD_ACCESS ?
> > 
> > Perhaps something like the following ?
> 
> Dear um folks, is this indeed the best solution? It's a bit sad to have
> to add this to x86_64, but if that's the way it is...
> 

I guess we can add load_unaligned_zeropad() or even just somehow add the
include with it (asm/word-at-a-time.h) from x86?

johannes

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