Hi Tom, On Thu, Jun 19, 2025 at 2:27 PM Tom Rini <[email protected]> wrote: > > On Thu, Jun 19, 2025 at 01:37:53PM -0700, Tony Dinh wrote: > > Hi Jerome, > > > > While fixing some ext4 file system problems on 2025.07-rc4, I ran into > > a problem booting a few Kirkwood boards. kwboot loaded the u-boot > > image, > > and then u-boot execution was frozen without anything going to the > > serial console. I did a bisect and found the commit that caused it. > > > > https://github.com/trini/u-boot/commit/6fe50e39508043f386fc1bd40bbc02b8a75c1940 > > > > When I tried to reverse this commit, I had a build error like this > > "{standard input}:24246: Error: selected processor does not support > > `mrc p15,1,r3,c15,c1,0' in Thumb mode" > > > > Currently, the only way to boot Kirkwood boards is to disable either > > CONFIG_LTO or CONFIG_SYS_THUMB_BUILD or both. > > > > I'm using the pogo_v4 and nsa325 boards as test beds. Please let me > > know if I can help with testing to troubleshoot this regression. > > I wonder if the right answer is that CONFIG_SYS_THUMB_BUILD should be > off? A quick look around and this (and sheevaplug) are ARM926EJ-S which > is Thumb-1 not Thumb-2 and it looks like the kernel for example only > supports building itself with thumb2 on armv7/v7m. I know that this was > working, so we should dig more too, but I'm not sure what the best > answer here is.
I recalled we added support for Thumb-1 from way back and a few people have helped porting more changes from the Linux kernel. U-boot has grown larger and larger over the years, especially with bootstd enabled (I know you have been watching closely for size growth). Built without CONFIG_SYS_THUMB_BUILD, the sheevaplug board is about 107K over the CONFIG_BOARD_SIZE_LIMIT of 512K. And it would be an unpleasant surprise to see size growth for other downstream projects still supporting Kirkwood SoCs. All the best, Tony > > -- > Tom
