[FSL P50xx] IRQ issues

[Nicholas Piggin]

Nice, thanks for reporting and testing. I submitted a qemu patch to 
hopefully avoid this happening again in future.

Thanks,
Nick

Excerpts from Christian Zigotzky's message of July 7, 2021 1:22 am:
> Hi Nick,
> 
> Your patch works (see patch below)! Many thanks for your help! We tested 
> it on an A-EON AmigaOne X5000/20 and in a virtual e5500 QEMU machine today.
> 
> Screenshots:
> 
> - 
> http://www.skateman.nl/wp-content/uploads/2021/07/Screenshot-at-2021-07-06-113237.png
> - https://i.ibb.co/h813RRp/Kernel-5-14-alpha3-Power-PC.png
> 
> Thanks,
> Christian
> 
> On 06 July 2021 at 06:07 am, Christian Zigotzky wrote:
>> Hi Nick,
>>
>> Thanks a lot for your patch! We will test it as soon as possible. 
>> You're right that this issue doesn't exist in a virtual e5500 QEMU 
>> machine.
>>
>> Have a nice day,
>> Christian
>>
>> On 06 July 2021 at 01:36 am, Nicholas Piggin wrote:
>>> Excerpts from Christian Zigotzky's message of July 6, 2021 4:49 am:
>>>> Hi All,
>>>>
>>>> Our FSL P50xx machines don't boot anymore because of IRQ issues. [1]
>>>>
>>>> Please check the IRQ changes in the latest PowerPC updates 5.14-1. [2]
>>>>
>>>> Thanks,
>>>> Christian
>>>>
>>>> [1]
>>>> https://forum.hyperion-entertainment.com/download/file.php?id=2592&mode=view 
>>>>
>>>> [2]
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=019b3fd94ba73d3ac615f0537440b81f129821f6 
>>>>
>>> This looks like mtmsrd in the 64e code. I think this should fix it.
>>>
>>> QEMU does not seem to trap on this, maybe something to improve.
>>>
>>> Thanks,
>>> Nick
>>> -- 
>>>
>>> diff --git a/arch/powerpc/kernel/interrupt_64.S 
>>> b/arch/powerpc/kernel/interrupt_64.S
>>> index 4063e8a3f704..d4212d2ff0b5 100644
>>> --- a/arch/powerpc/kernel/interrupt_64.S
>>> +++ b/arch/powerpc/kernel/interrupt_64.S
>>> @@ -311,9 +311,13 @@ END_BTB_FLUSH_SECTION
>>>        * trace_hardirqs_off().
>>>        */
>>>       li    r11,IRQS_ALL_DISABLED
>>> -    li    r12,-1 /* Set MSR_EE and MSR_RI */
>>>       stb    r11,PACAIRQSOFTMASK(r13)
>>> +#ifdef CONFIG_PPC_BOOK3S
>>> +    li    r12,-1 /* Set MSR_EE and MSR_RI */
>>>       mtmsrd    r12,1
>>> +#else
>>> +    wrteei    1
>>> +#endif
>>>         /* Calling convention has r9 = orig r0, r10 = regs */
>>>       mr    r9,r0
>>
> 
>