boot hang issue on S5PV210 with the latest kernel

Hi all,

I am testing the latest kernel(4.8+) on my S5PV210 ARM boards. I found I
have to add the kputc debug in __armv7_mmu_cache_on in
boot/compressed/head.S:
mov r11, r3
kputc #'x'
mov r3, r11

Without the above kputc, the kernel boot hang, there is no any output on UART

Any suggestions?

Thanks,
Yong