[U-Boot] [PATCH 2/2] x86: Allow 32-bit toolchain to compile 64-bit U-Boot

[Bin Meng]

Attempting to use a 32-bit toolchain (eg: kernel.org 4.9
i386-linux-gcc) to compile 64-bit U-Boot (qemu-x86_64_defconfig)
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 with 32-bit toolchain compiling sources for 64-bit.
Using a 64-bit toolchain (eg: kernel.org 4.9 x86_64-linux-gcc)
works out of the box. When compiling sources for 32-bit, '-m32' is
passed to the toolchain (no matter it's 32-bit or 64-bit).

Now do the same thing, passing '-m64' to the toolchain for 64-bit
sources build.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 arch/x86/config.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/config.mk b/arch/x86/config.mk
index 043425e..8835dcf 100644
--- a/arch/x86/config.mk
+++ b/arch/x86/config.mk
@@ -26,7 +26,7 @@ endif
 ifeq ($(IS_32BIT),y)
 PLATFORM_CPPFLAGS += -march=i386 -m32
 else
-PLATFORM_CPPFLAGS += $(if $(CONFIG_SPL_BUILD),,-fpic) -fno-common
+PLATFORM_CPPFLAGS += $(if $(CONFIG_SPL_BUILD),,-fpic) -fno-common -m64
 endif
 
 PLATFORM_RELFLAGS += -ffunction-sections -fvisibility=hidden
-- 
2.9.2