On 25/11/2021 12:47, Alistair Francis wrote:
On Wed, Nov 24, 2021 at 5:33 PM Philippe Mathieu-Daudé <f4...@amsat.org> wrote:
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);
}
That seems like a good option! I think we could add this to the CPU
realise function.
The problem with a riscv128-sofmmu executable is that it's hard to get
rid of in the future. We are very slowly moving towards a single
executable and adding a new one means we are stuck with it for a
while.
Alistair
Ooups, I replied yesterday to Philippe that I would work that out, but I
missed the reply all button, sorry.
Frédéric
Regards,
Phil.
--
+---------------------------------------------------------------------------+
| Frédéric Pétrot, Pr. Grenoble INP-Ensimag/TIMA, Ensimag deputy director |
| Mob/Pho: +33 6 74 57 99 65/+33 4 76 57 48 70 Ad augusta per angusta |
| http://tima.univ-grenoble-alpes.fr frederic.pet...@univ-grenoble-alpes.fr |
+---------------------------------------------------------------------------+