From: Marc Zyngier <maz@kernel.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Morten Rasmussen <Morten.Rasmussen@arm.com>,
Suren Baghdasaryan <surenb@google.com>,
kernel-team@android.com
Subject: Re: [PATCH 2/6] arm64: Allow mismatched 32-bit EL0 support
Date: Thu, 12 Nov 2020 17:06:20 +0000 [thread overview]
Message-ID: <901a3fe0c600d81d6097fe31b0b9b02b@kernel.org> (raw)
In-Reply-To: <20201112164943.7kdskvxcnuodphow@e107158-lin.cambridge.arm.com>
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...
next prev parent reply other threads:[~2020-11-12 17:06 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 21:51 [PATCH 0/6] An alternative series for asymmetric AArch32 systems Will Deacon
2020-10-27 21:51 ` [PATCH 1/6] KVM: arm64: Handle Asymmetric " Will Deacon
2020-10-27 21:51 ` [PATCH 2/6] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-10-28 11:12 ` Catalin Marinas
2020-10-28 11:17 ` Will Deacon
2020-10-28 11:22 ` Catalin Marinas
2020-10-28 11:23 ` Will Deacon
2020-10-28 11:49 ` Catalin Marinas
2020-10-28 12:40 ` Will Deacon
2020-10-28 18:56 ` Catalin Marinas
2020-10-29 22:20 ` Will Deacon
2020-10-30 11:18 ` Catalin Marinas
2020-10-30 16:13 ` Will Deacon
2020-11-02 11:44 ` Catalin Marinas
2020-11-05 21:38 ` Will Deacon
2020-11-06 12:54 ` Qais Yousef
2020-11-06 13:00 ` Will Deacon
2020-11-06 14:48 ` Qais Yousef
2020-11-09 13:52 ` Will Deacon
2020-11-11 16:27 ` Qais Yousef
2020-11-12 10:24 ` Will Deacon
2020-11-12 11:55 ` Qais Yousef
2020-11-12 16:49 ` Qais Yousef
2020-11-12 17:06 ` Marc Zyngier [this message]
2020-11-12 17:36 ` Qais Yousef
2020-11-12 17:44 ` Will Deacon
2020-11-12 17:36 ` Will Deacon
2020-11-13 10:45 ` Qais Yousef
2020-11-06 14:30 ` Catalin Marinas
2020-10-28 11:18 ` Catalin Marinas
2020-10-28 11:21 ` Will Deacon
2020-10-27 21:51 ` [PATCH 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-10-27 21:51 ` [PATCH 4/6] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-10-28 12:10 ` Catalin Marinas
2020-10-28 12:36 ` Will Deacon
2020-10-27 21:51 ` [PATCH 5/6] arm64: Advertise CPUs capable of running 32-bit applcations in sysfs Will Deacon
2020-10-28 8:37 ` Greg Kroah-Hartman
2020-10-28 9:51 ` Will Deacon
2020-10-28 12:15 ` Catalin Marinas
2020-10-28 12:27 ` Will Deacon
2020-10-28 15:14 ` Catalin Marinas
2020-10-28 15:35 ` Will Deacon
2020-10-27 21:51 ` [PATCH 6/6] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-10-29 18:42 ` [PATCH 0/6] An alternative series for asymmetric AArch32 systems Suren Baghdasaryan
2020-10-29 22:17 ` Will Deacon
2020-10-30 16:16 ` Marc Zyngier
2020-10-30 16:24 ` Will Deacon
2020-10-30 17:04 ` Marc Zyngier
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