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

[Szabolcs Nagy]

The 04/24/2020 12:47, Richard Henderson wrote:
> On 4/21/20 9:39 PM, Richard Henderson wrote:
> > Yep.  I failed to update aarch64_pstate_valid_mask for TCO.
> > Will fix.  Thanks,
> 
> Fixed on the branch.
> 
> I still need to work out how best to plumb the arm,armv8.5-memtag property so
> the devel/mte-v3 kernel branch isn't usable as-is for the moment.  For myself,
> I've just commented that test out for now.

The fix worked well thanks (in linux devel/mte-v3 i
reverted the patch that introduced arm,armv8.5-memtag)

However later on during testing malloc with PROT_MTE
i got a qemu assert failure:

Bail out! ERROR:/S/target/arm/mte_helper.c:97:allocation_tag_mem: assertion 
failed: (tag_size <= in_page)

i can reproduce it, but i don't know how to debug it
further, i don't know what the application is doing
when this happens, nor what the kernel is doing.

i rebuilt qemu with --enable-debug but now it's very
slow (still booting into linux 3h later).

let me know if there are ways to narrow this down.