Re: [PATCH v2] firmware_loader: Align .builtin_fw to 8

From: Doug Anderson <dianders@chromium.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Fangrui Song <maskray@google.com>, Arnd Bergmann <arnd@arndb.de>,
	linux-arch <linux-arch@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v2] firmware_loader: Align .builtin_fw to 8
Date: Fri, 5 Feb 2021 09:19:33 -0800	[thread overview]
Message-ID: <CAD=FV=UTQCdd9dDG8W8fZZZhSPY3cwWgZk-3VYXZdz6pRbp8Ow@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=XUuo3OaDVOnFiczUTeyKt1moX7nQ+XEX_HiDpv2f3k8A@mail.gmail.com>

Hi,

On Fri, Jan 22, 2021 at 11:04 AM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Tue, Jan 5, 2021 at 11:20 AM Nick Desaulniers
> <ndesaulniers@google.com> wrote:
> >
> > On Tue, Jan 5, 2021 at 9:45 AM Doug Anderson <dianders@chromium.org> wrote:
> > >
> > > Hi,
> > >
> > > On Mon, Dec 7, 2020 at 9:49 PM Fangrui Song <maskray@google.com> wrote:
> > > >
> > > > arm64 references the start address of .builtin_fw (__start_builtin_fw)
> > > > with a pair of R_AARCH64_ADR_PREL_PG_HI21/R_AARCH64_LDST64_ABS_LO12_NC
> > > > relocations. The compiler is allowed to emit the
> > > > R_AARCH64_LDST64_ABS_LO12_NC relocation because struct builtin_fw in
> > > > include/linux/firmware.h is 8-byte aligned.
> > > >
> > > > The R_AARCH64_LDST64_ABS_LO12_NC relocation requires the address to be a
> > > > multiple of 8, which may not be the case if .builtin_fw is empty.
> > > > Unconditionally align .builtin_fw to fix the linker error. 32-bit
> > > > architectures could use ALIGN(4) but that would add unnecessary
> > > > complexity, so just use ALIGN(8).
> > > >
> > > > Fixes: 5658c76 ("firmware: allow firmware files to be built into kernel image")
> > > > Link: https://github.com/ClangBuiltLinux/linux/issues/1204
> > > > Reported-by: kernel test robot <lkp@intel.com>
> > > > Signed-off-by: Fangrui Song <maskray@google.com>
> > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > >
> > > > ---
> > > > Change in v2:
> > > > * Use output section alignment instead of inappropriate ALIGN_FUNCTION()
> > > > ---
> > > >  include/asm-generic/vmlinux.lds.h | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > Tested-by: Douglas Anderson <dianders@chromium.org>
> > >
> > > For whatever reason this is hitting developers on Chrome OS a whole
> > > lot suddenly.  Any chance it could be landed?  Which tree should it go
> > > through?
> >
> > Andrew,
> > Would you mind picking up this patch for us, please?
> > https://lore.kernel.org/lkml/20201208054646.2913063-1-maskray@google.com/
>
> I just synced today and I'm still hitting this error when building
> mainline.  Perhaps Andrew is busy and someone else can pick it up?
> It'd be nice to get this into v5.11

I hate to be a broken record, but I synced and built mainline today
(v5.11-rc6-139-gdd86e7fa07a3) and I'm still hitting this.  It feels
like we need an alternate way to get this landed...

-Doug