Re: tst-arm-mte bug: PSTATE.TCO is cleared on exceptions

[Richard Henderson]

On 4/20/20 3:29 AM, Szabolcs Nagy wrote:
> i'm using the branch at
> 
> https://github.com/rth7680/qemu/tree/tgt-arm-mte
> 
> to test armv8.5-a mte and hope this is ok to report bugs here.
> 
> i'm doing tests in qemu-system-aarch64 with linux userspace
> code and it seems TCO bit gets cleared after syscalls or other
> kernel entry, but PSTATE is expected to be restored, so i
> suspect it is a qemu bug.
> 
> i think the architecture saves/restores PSTATE using SPSR_ELx
> on exceptions.

Yep.  I failed to update aarch64_pstate_valid_mask for TCO.
Will fix.  Thanks,


r~

> 
> i used the linux branch
> https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=devel/mte-v2
> 
> attached a reproducer that segfaults in qemu but should work.
> 
> thanks.
>