On 11/12/20 17:36, Will Deacon wrote: > On Thu, Nov 12, 2020 at 04:49:43PM +0000, 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? > > | CPU features: CPU4: Detected conflict for capability 53 (32-bit EL1 Support), System: 1, CPU: 0 > > So we're doing the right thing here. Okay. So the systems we test on will always fail until we have real hardware. Makes sense. > I've already queued fixes for the splat in for-next/fixes, as it's > unrelated. Great thanks! Cheers -- Qais Yousef
