On Wed, Jan 11, 2023 at 08:30:20AM +0000, Emmanuel Dreyfus wrote:
> An interesting problem on an all-in-one HP PC. Booting
> NetBSD-10.0_BETA/amd64 (or prior versions) works fine until the
> kernel starts displaying its messages. At that point the screen
> turns dark.
So far, the thing seems to crash very early in bootstrap, probably
before main().
By adding printf in bootx64.efi (and commenting out ExitBootServices
call so that I can see it), I know I reach the point where
startprog64 is called.
Debugging what happens after that is more tricky. This is assembly
code, I am not sure I can printf from there. I try to make the
machine reboot at startprog64() start to see if I just reach that
place.
Searching the web suggests inserting this at the begining of
startprog64 could do it:
/* jmp 0xffff:0 to reset */
.byte 0xea
.byte 0x00
.byte 0x00
.byte 0xff
.byte 0xff
With that change, the all-in-one PC still hangs, while another machine
does reboot. That may be a question for port-i386@, but is that
debugging technique relibale? Is there something else to try?
If the technique is reliable, then I can only imagine the stack
got corrupted enough that the call to startprog64() does not even
reach it.
--
Emmanuel Dreyfus
m...@netbsd.org
