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, 22 Jan 2021 11:04:02 -0800	[thread overview]
Message-ID: <CAD=FV=XUuo3OaDVOnFiczUTeyKt1moX7nQ+XEX_HiDpv2f3k8A@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOdkFpqEDvJ5b9wpwEhnOdh-YJ8GxCc33JcHXqNRDnO=RfQ@mail.gmail.com>

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

-Doug