[U-Boot] [PATCH v2 2/2] x86: Enforce toolchain to generate 64-bit codes for 64-bit U-Boot

[Simon Glass]

On 27 July 2017 at 07:12, Bin Meng <bmeng.cn at gmail.com> wrote:
> 64-bit U-Boot image is a combination of 32-bit U-Boot (SPL) plus
> 64-bit U-Boot (proper). For the U-Boot proper, it has be compiled
> to 64-bit object codes. Attempting to use a toolchain to compile
> 64-bit U-Boot for qemu-x86_64, like kernel.org 4.9 i386-linux-gcc,
> fails with the following errors:
>
>   arch/x86/cpu/intel_common/microcode.c:79:2: error: PIC register
>   clobbered by 'ebx' in 'asm'
>
> The issue is because toolchain is preconfigured to generate code
> for the 32-bit architecture (i386), and currently '-m64' is missing
> in the makefile fragment. Using kernel.org 4.9 x86_64-linux-gcc
> works out of the box, since it is preconfigured to generate 64-bit
> codes.
>
> When compiling U-Boot SPL, '-m32' is passed to the toolchain, no
> mater 32-bit (i386-linux-) or 64-bit (x86_64-linux) the toolchain
> is preconfigured to generate.
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>
> ---
>
> Changes in v2:
> - reword the commit message
>
>  arch/x86/config.mk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Simon Glass <sjg at chromium.org>