Hi Frédéric,
On 11/24/21 07:55, Frédéric Pétrot wrote:
> On 24/11/2021 07:12, Alistair Francis wrote:
>> On Sat, Nov 13, 2021 at 1:16 AM Frédéric Pétrot
>> <frederic.pet...@univ-grenoble-alpes.fr> wrote:
>>>
>>> This patch is kind of a mess because several files have to be slightly
>>> modified to allow for a new target. In the current status, we have done
>>> our best to have RV64 and RV128 under the same RV64 umbrella, but there
>>> is still work to do to have a single executable for both.
>>> In particular, we have no atomic accesses for aligned 128-bit addresses.
>>>
>>> Once this patch applied, adding risc128-sofmmu to --target-list produces
>>> a (no so useful yet) executable.
>>
>> I can't remember if we discussed this before, but do we need the
>> riscv128-sofmmu executable? Can we instead just use a riscv64-sofmmu
>> executable?
>
> Hello Alistair,
> Richard was also advocating for a single executable, but pointed out that
> we need to disable mttcg because there is a need for specific tcg
> support for
> 128-bit aligned atomics.
> Given my understanding of that part of QEMU, I choose the easy way to
> disable
> it once and for all at compile time until we have that.
In rv128_base_cpu_init():
if (qemu_tcg_mttcg_enabled) {
/* Missing 128-bit aligned atomics */
error_report("128-bit RISC-V currently does not work"
" with Multi Threaded TCG. Please use:"
" -accel tcg,thread=single");
exit(EXIT_FAILURE);
}
Regards,
Phil.
