Re: [arm] Dom0 hangs after enable KROBE_EVENTS and/or UPROBE_EVENTS in kernel config

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 22 Jul 2021, Julien Grall wrote:
> > You can go and edit 76085aff29f585139a37a10ea0a7daa63f70872c to change
> > from 4K to any multiple of 4K, e.g. 8K, 12K, 16K, 20K. They should all
> > work the same.
> > 
> > Looking at the boot logs on pastebin I noticed that Xen is not loaded at
> > a 2MB aligned address. I recommend you change Xen loading address to
> > 0x500200000. And the kernel loading address to 0x500400000.
> 
> I am curious to know why you recommend to load at 2MB aligned address. The
> Image protocol doesn't require to load a 2MB aligned address. In fact, we add
> issue on Juno because the bootloader would load Xen at a 4KB address. UEFI
> will also load at a 4KB align address.

It is from empirical evidence :-)

I cannot tell you the exact reason but I saw "strange" problems in the
past that went away after choosing a 2MB alignment. So we settled for
using 2MB in ImageBuilder and we haven't seen any more issues.

However, it could have been anything: a bug in U-Boot not relevant
anymore, a bug in Linux, etc. I don't know for sure.