Re: [Xenomai] [PATCH] ipipe: Re-fix migration helper for legacy users

[Philippe Gerum <rpm@xenomai.org>]

On 01/17/2013 10:14 AM, Jan Kiszka wrote:
> On 2013-01-17 10:12, Philippe Gerum wrote:
>> On 01/17/2013 09:51 AM, Philippe Gerum wrote:
>>> On 01/17/2013 09:34 AM, Jan Kiszka wrote:
>>>> On 2013-01-17 09:26, Philippe Gerum wrote:
>>>>> On 01/16/2013 08:17 PM, Jan Kiszka wrote:
>>>>>> In the legacy use case, __ipipe_switch_tail will be invoked over the
>>>>>> non-root domain after hardening. So clearing of TASK_HARDENING must
>>>>>> not
>>>>>> be restricted to root.
>>>>>>
>>>>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>>>>> ---
>>>>>>
>>>>>> For the case my analysis was right. With this, Xenomai 2.6 works again
>>>>>> here.
>>>>>>
>>>>>>     kernel/ipipe/core.c |    2 ++
>>>>>>     1 files changed, 2 insertions(+), 0 deletions(-)
>>>>>>
>>>>>> diff --git a/kernel/ipipe/core.c b/kernel/ipipe/core.c
>>>>>> index 6929156..4695ba8 100644
>>>>>> --- a/kernel/ipipe/core.c
>>>>>> +++ b/kernel/ipipe/core.c
>>>>>> @@ -1124,7 +1124,9 @@ int __ipipe_switch_tail(void)
>>>>>>         hard_local_irq_disable();
>>>>>>     #endif
>>>>>>         x = __ipipe_root_p;
>>>>>> +#ifndef CONFIG_IPIPE_LEGACY
>>>>>>         if (x)
>>>>>> +#endif
>>>>>>             complete_domain_migration();
>>>>>>
>>>>>>     #ifndef CONFIG_IPIPE_WANT_PREEMPTIBLE_SWITCH
>>>>>>
>>>>>
>>>>> The analysis is right. I already fixed this bug in the 3.5 branch, we
>>>>> are missing a forward port to 3.5.7.
>>>>>
>>>>> http://git.denx.de/?p=ipipe-2.6.git;a=commit;h=8b11dc5fee73842a24ec4367b57aaa2dcdd67225
>>>>>
>>>>>
>>>>
>>>> Would you push your new version?
>>>>
>>>> Jan
>>>
>>> These patches introduced between core-3.5-2 and core-3.5-3 were not
>>> propagated to core-3.5.7. They are on their way now.
>>>
>>> ba77ad1 powerpc/ipipe: prevent spurious hw IRQ enabling in activate_mm()
>>> 8b11dc5 ipipe: fix domain migration helper
>>> 1f0d763 x86_64/ipipe: introduce ipipe_clock_name()
>>>
>>
>> 8b11dc5 would reintroduce the issue you saw in legacy mode though. Fix
>> on its way.
>
> Not sure what you were looking at: 8b11dc5 is part of your public
> core-3.5 branch. I was rebasing over it, testing the result and found
> his bug.
>
> Jan
>

We have two bugs in the migration handling in core-3.5.7: one preventing 
the hardening bit to be cleared in legacy mode when running over the 
head domain, the other allowing the migration hook to be fired over the 
head domain. The latter was fixed by 8b11dc5 in core-3.5, but we are 
missing that fix in core-3.5.7. However, that fix did not address the 
issue in legacy mode.

The new patch has to cope with both legacy and non-legacy in this area, 
and made available to 3.2, 3.4, 3.5 and 3.5.7.

-- 
Philippe.