确保ARCH=arm64，并且使用64bit的编译器进行编译，否则会出现如下错误。

玩转树莓派4B之Uboot移植

配置uboot工具链生成64位的 (32位就是个弟弟，有时候多玩玩64位的吧)
export ARCH=arm64
export CROSS_COMPILE=aarch64-linux-gnu-
（32位就改成：export CROSS_COMPILE=arm-linux-gnueabi-）
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原文链接：https://blog.csdn.net/u010629326/java/article/details/101555576Screen Shot 2020-07-08 at 15.57.39.png](https://img.haomeiwen.com/i14412485/d23f6418908c21b6.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

include/asm-generic/bitops/__fls.h:38:21: warning: left shift count >= width of type [-Wshift-count-overflow]
if (!(word & (~0ul << (BITS_PER_LONG-1))))
^~
arm-linux-gnueabi-ld.bfd -r -o drivers/crypto/built-in.o drivers/crypto/rsa_mod_exp/built-in.o drivers/crypto/fsl/built-in.o
In file included from include/common.h:52:0,
from drivers/input/keyboard-uclass.c:6:
include/dm/of.h: At top level:
./arch/arm/include/asm/global_data.h:110:58: error: invalid register name for ‘gd’

define DECLARE_GLOBAL_DATA_PTR register volatile gd_t *gd asm ("x18")

                                                      ^

include/dm/of.h:86:1: note: in expansion of macro ‘DECLARE_GLOBAL_DATA_PTR’
DECLARE_GLOBAL_DATA_PTR;
^~~~~~~~~~~~~~~~~~~~~~~
scripts/Makefile.build:278: recipe for target 'drivers/input/keyboard-uclass.o' failed
make[2]: *** [drivers/input/keyboard-uclass.o] Error 1
scripts/Makefile.build:432: recipe for target 'drivers/input' failed
make[1]: *** [drivers/input] Error 2
Makefile:1629: recipe for target 'drivers' failed
make: *** [drivers] Error 2
Makefile:1629: recipe for target 'cmd' failed
make: *** [cmd] Error 2