位于arch/arm/lib/vectors.S文件中存有uboot执行的第一段代码_start。
.globl _start
/*
*************************************************************************
*
* Vectors have their own section so linker script can map them easily
*
*************************************************************************
*/
.section ".vectors", "ax"
/*
*************************************************************************
*
* Exception vectors as described in ARM reference manuals
*
* Uses indirect branch to allow reaching handlers anywhere in memory.
*
*************************************************************************
*/
_start:
#ifdef CONFIG_SYS_DV_NOR_BOOT_CFG
.word CONFIG_SYS_DV_NOR_BOOT_CFG
#endif
b reset
...
可以看到它会跳转到reset(位于arch/arm/cpu/armv7/start.S), 关于start.S 请看下一篇博文。