On 11/22/24 10:35, Stafford Horne wrote:
I just regression tested linux-6.12 against qemu-9.2.0-rc1 and I'm still
getting no output from or1k, with the current image or the old or1k release
image that worked under old qemu versions.
I tried applying your serial patch to current qemu, and it made no
difference: still no output booting the image.
OK, I am trying to get that patch pushed upstream. I will be sure we fix your
issues before we do that.
Thanks. Let me know how/if I can help.
Alas I can no longer test that reverting the commit I identified (git show
$HASH | patch -p1 -r) makes it work again in current qemu (although it did
at one point, that's a standard sanity check at the end of bisect for me),
and I can't fix it up by hand either because hw/openrisc/openrisc_sim.c no
longer contains the string "load_sim", looks like it got collated with
common code for other architectures.
I'm happy to tweak the kernel config if qemu changed in a way that broke
compatibility with old images (I assume _you_ have a kernel that boots), but
I was hoping "this week's kernel release" would have any necessary patches
to work with QEMU's changed ABI.
The patch I have put in 6.12 only helps with earlycon. Regular output has
always been working for me. I will work on testing your image again to see what
is special about it.
Just a guess, but given the alignment change, I suspect it's barfing on
the statically linked initramfs? That seems the most likely step to go
off the rails given the failing patch is a symbol alignment change in
the flattened device tree plumbing, and I think the initramfs extractor
parses device trees very early on to find stuff (I forget why). Moving
"where the data lives" without a corresponding change to the "where to
look for the data" code seems a bit strange, but it's not my area...
Here's the miniconfig I built 6.12 with (90% of which is generic to all
the architectures I'm testing, the sections are labeled. The
console="FIXME" bit is because I can't get qemu-system-or1k -append
"blah" to go through to linux, so I stuck FIXME in that field for the
or1k target and it wound up in the output):
# make ARCH=openrisc allnoconfig KCONFIG_ALLCONFIG=linux-miniconfig
# make ARCH=openrisc -j $(nproc)
# boot vmlinux console=FIXME
# architecture independent
CONFIG_PANIC_TIMEOUT=1
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_RD_GZIP=y
CONFIG_BINFMT_ELF=y
CONFIG_BINFMT_SCRIPT=y
CONFIG_BLK_DEV=y
CONFIG_BLK_DEV_INITRD=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_EXT4_FS=y
CONFIG_EXT4_USE_FOR_EXT2=y
CONFIG_VFAT_FS=y
CONFIG_FAT_DEFAULT_UTF8=y
CONFIG_MISC_FILESYSTEMS=y
CONFIG_NLS_CODEPAGE_437=y
CONFIG_NLS_ISO8859_1=y
CONFIG_SQUASHFS=y
CONFIG_SQUASHFS_XATTR=y
CONFIG_SQUASHFS_ZLIB=y
CONFIG_TMPFS=y
CONFIG_TMPFS_POSIX_ACL=y
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
CONFIG_NET=y
CONFIG_NETDEVICES=y
CONFIG_NET_CORE=y
CONFIG_NETCONSOLE=y
CONFIG_PACKET=y
CONFIG_UNIX=y
CONFIG_INET=y
CONFIG_IPV6=y
CONFIG_ETHERNET=y
CONFIG_COMPAT_32BIT_TIME=y
CONFIG_EARLY_PRINTK=y
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
# architecture specific
CONFIG_ETHOC=y
CONFIG_SERIO=y
CONFIG_SERIAL_OF_PLATFORM=y
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_OPENRISC_BUILTIN_DTB="or1ksim"
# architecture extra
CONFIG_INITRAMFS_SOURCE="../../root/or1k/fs"
And then run-qemu.sh is just:
DIR="$(dirname $0)"; qemu-system-or1k -M or1k-sim -m 256 "$@" -nographic
-no-reboot -kernel "$DIR"/linux-kernel -append "HOST=or1k console=FIXME
$KARGS"
echo -e '\e[?7h'
(The echo is because some qemu bioses disable wordwrap in the terminal
and leave it broken, driving bash cursor-up history nuts. My plumbing
just sticks a reset in all the architectures' scripts...)
The or1k support in mkroot is the 4 lines at:
https://github.com/landley/toybox/blob/master/mkroot/mkroot.sh#L256
(I'd cut and paste them here but thunderbird wordwraps everything.)
Also, looking at that, I'm using a builtin DTB and you might be passing
one in via -dtb? Another thing the alignment change might break...
Note, I did find some issues with the kernel nor properly handling stdout-path.
It seems that if there are multiple uarts the first one will always be used as
the default uart. Only the console= command line argument can be used to
override that.
I've never managed to get console= to go through to linux in
qemu-system-or1k. The above tries but is ignored.
It's also doing a statically linked initramfs because -initrd didn't
work on this target. Happy to update if it's been fixed, the other
targets are almost all using -initrd to feed in an external cpio.gz
So as long as the kernel selects the first uart as the stdout path (it should
have always been the case) AND qemu picks the first uart as the uart connected
to the console (it should be with my latest patch) we should get serial output.
The commit in question is not changing UART configuration. It's changing
the alignment of a symbol. Your patch to the UART plumbing did not fix
it. I don't see how the UART configuration could have changed between
the "working" and "not working" states.
Another thing that may get me delayed is that I need to rebuild my or1k-elf-gdb
as it's python version is no longer compatible with the kernel's python.
Yeah, Python 3's forced upgrade treadmill is deeply silly. I'm not a
fan: https://landley.net/notes-2024.html#09-04-2024
(I know they're doing it to make sure they never have another "our
userbase refuses to move off 2.0 for a full decade" moment by holding
tightly to the control they wrested away from their users and never
giving an inch back now they've forced the issue, by making sure their
code spoils like milk and the installed base is regularly slashed and
burned, but for me that just means "use lua" or something. Yes your dev
team had trauma. So did the perl guys, who eventually gave UP forcing
their transition down an unwilling userbase's throat... But again, not
my area.)
-Stafford
Rob
