Re: [PATCH V2 18/24] irqchip: mips-gic: Stop using per-platform mapping tables

From: James Hogan
Date: Thu Jan 15 2015 - 12:25:16 EST


On 15/01/15 16:58, Andrew Bresticker wrote:
> Hi James, Qais,
>
> On Thu, Jan 15, 2015 at 8:36 AM, Qais Yousef <qais.yousef@xxxxxxxxxx> wrote:
>> On 01/15/2015 04:29 PM, James Hogan wrote:
>>>
>>> On 15/01/15 11:59, James Hogan wrote:
>>>>
>>>> Hi Andrew,
>>>>
>>>> On 18/09/14 22:47, Andrew Bresticker wrote:
>>>>>
>>>>> Now that the GIC properly uses IRQ domains, kill off the per-platform
>>>>> routing tables that were used to make the GIC appear transparent.
>>>>>
>>>>> This includes:
>>>>> - removing the mapping tables and the support for applying them,
>>>>> - moving GIC IPI support to the GIC driver,
>>>>> - properly routing the i8259 through the GIC on Malta, and
>>>>> - updating IRQ assignments on SEAD-3 when the GIC is present.
>>>>>
>>>>> Platforms no longer will pass an interrupt mapping table to gic_init.
>>>>> Instead, they will pass the CPU interrupt vector (2 - 7) that they
>>>>> expect the GIC to route interrupts to. Note that in EIC mode this
>>>>> value is ignored and all GIC interrupts are routed to EIC vector 1.
>>>>>
>>>>> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
>>>>> Acked-by: Jason Cooper <jason@xxxxxxxxxxxxxx>
>>>>> Reviewed-by: Qais Yousef <qais.yousef@xxxxxxxxxx>
>>>>> Tested-by: Qais Yousef <qais.yousef@xxxxxxxxxx>
>>>>
>>>> This commit (18743d2781d01d34d132f952a2e16353ccb4c3de) appears to break
>>>> boot of interAptiv, dual core, dual vpe per core, on malta with
>>>> malta_defconfig.
>>>>
>>>> It gets to here:
>>>> ...
>>>> CPU1 revision is: 0001a120 (MIPS interAptiv (multi))
>>>> FPU revision is: 0173a000
>>>> Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
>>>> Primary data cache 64kB, 4-way, PIPT, no aliases, linesize 32 bytes
>>>> MIPS secondary cache 1024kB, 8-way, linesize 32 bytes.
>>>> Synchronize counters for CPU 1: done.
>>>> Brought up 2 CPUs
>>>>
>>>> and then appears to just hang. Passing nosmp works around it, allowing
>>>> it to get to userland.
>>>>
>>>> Is that a problem you've already come across?
>>>>
>>>> I'll keep debugging.
>>>
>>> Right, it appears the CPU IRQ line that the GIC is using doesn't get
>>> unmasked (STATUSF_IP2) when a new VPE is brought up, so only the first
>>> CPU will actually get any interrupts after your patch (including the
>>> rather critical IPIs), i.e. hacking it in vsmp_init_secondary() in
>>> smp-mt.c allows it to boot.
>>>
>>> Hmm, I'll have a think about what the most generic fix is, since
>>> arbitrary stuff may or may not have registered handlers for the raw CPU
>>> interrupts (timer, performance counter, gic etc)...
>>>
>>> Cheers
>>> James
>>>
>>
>> Is this similar to the issue addressed by this (ff1e29ade4c6 MIPS: smp-cps:
>> Enable all hardware interrupts on secondary CPUs)?
>
> I believe so.
>
> James, I think you can apply a similar patch to smp-mt.c:vsmp_init_secondary.

Yes, I've come to the same conclusion. smp-cmp.c is also affected. I'll
post patches tomorrow.

Thanks
James

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