On 2020-11-12 16:49, Qais Yousef wrote:
On 11/12/20 11:55, Qais Yousef wrote:
On 11/12/20 10:24, Will Deacon wrote:
> On Wed, Nov 11, 2020 at 04:27:00PM +0000, Qais Yousef wrote:
> > On 11/09/20 13:52, Will Deacon wrote:
> > > On Fri, Nov 06, 2020 at 02:48:35PM +0000, Qais Yousef wrote:
> > > > On 11/06/20 13:00, Will Deacon wrote:
> > > > > On Fri, Nov 06, 2020 at 12:54:25PM +0000, Qais Yousef wrote:
> > > > > > FWIW I have my v3 over here in case it's of any help. It solves the problem of
> > > > > > HWCAP discovery when late AArch32 CPU is booted by populating boot_cpu_date
> > > > > > with 32bit features then.
> > > > > >
> > > > > > git clone https://git.gitlab.arm.com/linux-arm/linux-qy.git -b asym-aarch32-upstream-v3 origin/asym-aarch32-upstream-v3
> > > > >
> > > > > Cheers, I've done something similar. I was hoping to post it today, but I've
> > > > > been side-tracked with bug fixing this morning. The main headache I ended up
> > > > > with was allowing late-onlining of 64-bit-only CPUs if all the boot CPUs
> > > > > are 32-bit capable. What do you do in that case?
> > > >
> > > > Do you mean if CPUs 0-3 were 32bit capable and we boot with maxcpus=4 then
> > > > attempt to bring the remaining 64bit-only cpus online later?
> > >
> > > Right. I think we will refuse to online them. I'll post my attempt at
> > > handling that shortly.
> >
> > Sorry for the delayed response.
> >
> > You're right, I tried that and they refuse to come online. We missed that tbh.
> >
> > Haven't thought what we should do yet. I tried your v2 and it failed similarly.
>
> Hmm, it shouldn't do. Please could you provide the log? My hunch is that you
> are blatting 32-bit EL1 support as well, and we can't handle a mismatch for
> that with a late CPU. Do you know if the CPUs being integrated into these
> broken designs have a mismatch at EL1 as well?
Hmm my test could have been invalid then. We shouldn't have mismatch
at EL1,
for ease of testing I used a hacked up patch to fake asymmetry on
Juno. Testing
on FVP now, it takes time to boot up though..
Let me re-run this and get you the log from proper environment.
Assuming it
still fails.
Still fails the same on FVP. dmesg attached. There's a splat shortly
after
attempting to online CPU 4.
# cat /sys/devices/system/cpu/online
0-3
# cat /sys/devices/system/cpu/aarch32_el0
0-3
Now while writing this I just realized I tell the FVP to disable
aarch32
support at EL0. So this might still make the kernel thinks there's
AArch32
support at EL1 - which seems is what makes your series get confused?
You can't have AArch32 at EL1 and not have it at EL0.
Anyway. No real hardware to test on and not sure if I can tell the FVP
to
disable AArch32 support at EL1.
/me goes and dig
-C cluster0.max_32bit_el=-1 # no 32bit support whatsoever
-C cluster1.max_32bit_el=0 # 32bit support at EL0 only
M.
--
Jazz is not dead. It just smells funny...
