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

From: Nick Desaulniers <ndesaulniers@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: 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>,
	Doug Anderson <dianders@chromium.org>
Subject: Re: [PATCH v2] firmware_loader: Align .builtin_fw to 8
Date: Tue, 5 Jan 2021 11:20:07 -0800	[thread overview]
Message-ID: <CAKwvOdkFpqEDvJ5b9wpwEhnOdh-YJ8GxCc33JcHXqNRDnO=RfQ@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=WWSniXCaC+vAKRa1fCZB4_dbaejwq+NCF56aZFYE-Xsg@mail.gmail.com>

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/

-- 
Thanks,
~Nick Desaulniers