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

[Doug Anderson]

Hi,

On Mon, Dec 7, 2020 at 9:49 PM Fangrui Song <maskray@xxxxxxxxxx> 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@xxxxxxxxx>
> Signed-off-by: Fangrui Song <maskray@xxxxxxxxxx>
> Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
>
> ---
> 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@xxxxxxxxxxxx>

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?

-Doug