[Qemu-devel] Powerpc regressions?

[Rob Landley <rob@landley.net>]

If you grab this tarball:

http://impactlinux.com/fwl/downloads/binaries/system-image/system-image-powerpc.tar.bz2

Extract it, and ./run-emulator.sh.

This ran fine under svn 6657 (which is git 2d18e637e5ec).  The next commit screwed up openbios, but 
reverting openbios worked for a while.

In the last couple months, two problems have cropped up:

1) -hda sets /dev/hdc instead of /dev/hda (which is the cdrom).
2) The kernel panics running init:

Unable to handle kernel paging request for data at address 0x0000007c
Faulting instruction address: 0xc0125610
Oops: Kernel access of bad area, sig: 11 [#1]
PowerMac
NIP: c0125610 LR: c013ea9c CTR: c013ea88
REGS: c7827be0 TRAP: 0300   Not tainted  (2.6.29)
MSR: 00009032 <EE,ME,IR,DR>  CR: 42224022  XER: 00000000
DAR: 0000007c, DSISR: 40000000
TASK = c78257f0[1] 'init.sh' THREAD: c7826000
GPR00: c013ea9c c7827c90 c78257f0 00000000 c7825820 00000000 b2f34226 00000000 
GPR08: c7822ed8 00000001 c013ea88 00000000 58389c00 100834dc 28220022 10060000 
GPR16: 10080000 100852a8 00000000 10040000 00000000 c0310000 c031594c c0270000 
GPR24: 00000001 c0310000 0000000a c0310000 c02ee370 00000000 00000001 00000000 
NIP [c0125610] tty_wakeup+0x14/0xa0
LR [c013ea9c] uart_tasklet_action+0x14/0x24
Call Trace:
[c7827c90] [c0125630] tty_wakeup+0x34/0xa0 (unreliable)
[c7827ca0] [c013ea9c] uart_tasklet_action+0x14/0x24
[c7827cb0] [c00303c8] tasklet_action+0x88/0x104
[c7827cd0] [c00304d0] __do_softirq+0x8c/0x134
[c7827d10] [c0006ba0] do_softirq+0x58/0x5c
[c7827d20] [c003033c] irq_exit+0x94/0x98
[c7827d30] [c0006c40] do_IRQ+0x9c/0xc0
[c7827d50] [c0012778] ret_from_except+0x0/0x1c
--- Exception: 501 at uart_start+0x24/0x38
    LR = uart_start+0x20/0x38
[c7827e30] [c014043c] uart_write+0xc4/0xe8
[c7827e60] [c01293a0] n_tty_write+0x1d4/0x3c4
[c7827eb0] [c0126540] tty_write+0x180/0x268
[c7827ef0] [c007feec] vfs_write+0xc4/0x16c
[c7827f10] [c0080404] sys_write+0x4c/0x90
[c7827f40] [c00120ac] ret_from_syscall+0x0/0x40
--- Exception: c01 at 0x4803a2dc
    LR = 0x4804c490
Instruction dump:
38c00000 4bf02255 80010024 bba10014 38210020 7c0803a6 4e800020 9421fff0 
7c0802a6 bfc10008 7c7f1b78 90010014 <8003007c> 70090020 4082002c 387f00d8 
Kernel panic - not syncing: Fatal exception in interrupt

I note that this is the same kernel binary and same system image that used to run fine, only qemu changed.  
I can try to tweak the kernel .config to work around this, but I don't know what the actual problem is...

Suggestions?

Rob
-- 
Latency is more important than throughput. It's that simple. - Linus Torvalds