
On Tue, Jul 13, 2021 at 02:15:08PM +0500, Ahsan Hussain wrote:
Hello,
I'm dumbfounded by a seemingly unrelated early kernel hang/failing to boot when CONFIG_RANDOMIZE_BASE=n is set in kernel and we use FIT uImage. I've verified this behavior on a couple of i.MX8 SoCs (i.MX8M plus and i.MX8QXP) and the results remain consistent.
I'm able to boot kernel when I use booti command. However when I use bootm to boot a U-Boot fitImage (with kernel and fdt load addresses/entrypoint in .its file same as I used for booti command; also tried disabling relocation for fdt by setting fdt_high=~0UL), the boot gets stuck at "Starting kernel ...". On disabling RANDOMIZE_BASE kconfig in Linux the same fitImage is able to boot.
Can you say which address you're trying to load the kernel to?
I've tried enabling earlycon and U-Boot debug messages in common/bootm.c and arch/arm/lib/bootm.c but found no helpful difference in both boot flows. Please let me know if I'm missing something obvious or where do I start looking to debug this issue.
IIUC, the booti command respects the text_offset from the kernel header, whereas bootm will not. If you have a hard-coded offset, it's possible you're violating the offset the kernel expects, and where the kernel is not relocatable, if can't fix itself up.
I suspect you have a hard-coded offset of 0x80000, whereas recent kernels have a text offset of 0x00000. Your bootloader *should* read this dynamially rather than hard-coding it.
For details, see:
https://www.kernel.org/doc/html/v5.4/arm64/booting.html#call-the-kernel-imag...
Thanks, Mark.