Re: [PATCH] target/ppc: Fix e6500 boot

["Cédric Le Goater" <clg@kaod.org>]

On 12/25/21 22:53, BALATON Zoltan wrote:
> On Sat, 25 Dec 2021, mario@locati.it wrote:
>> I have tried to launch a freshly compiled qemu from git master on a NXP T2080RDB devkit that has a e6500 CPU in combination with a freshly compiled kernel 5.16-rc6
>> I have Debian SID ppc64 up and running using such a kernel, and when I launch qemu to run a VM with the same debian sid for ppc64 and the same kernel using --enable-kvm I end up with a kernel panic

Thanks for testing,

>>
>> [....]
>> Run /sbin/init as init process
>> random: fast init done
>> systemd[1]: illegal instruction (4) at 3fff96562ac8 nip 3fff96562ac8 lr 3fff96562aa8 code 1 in libc-2.32.so[3fff96516000+1f7000]

debian ppc64 sid has a glibc 2.33 AFAICT

>> systemd[1]: code: 60000000 38600006 9122b7e8 4801bead 60000000 60000000 8122b7e8 2c090004
>> systemd[1]: code: 40820014 39200005 60000000 9122b7e8 <00000000> 60000000 8122b7e8 2c090005
> 
> Looks like it trips on a 0 opcode here in the middle of other values that look like valid code so I wonder how that 0 got there? Did something overwrite it before it tried to execute it? 

This looks like the abort() routine.

> If it always happens on the same address maybe you could try attaching gdb and put a watch point on that address to see what writes there, otherwise I don't know how to debug this.

Could you deduce the routine name from the nip ?

Thanks,

C.