Re: [Xenomai] core-3.5 for x86

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 12/18/2012 12:23 PM, Jan Kiszka wrote:
> On 2012-12-15 20:16, Gilles Chanteperdrix wrote:
>> On 12/15/2012 11:03 PM, Wolfgang Mauerer wrote:
>>
>>> Hi Gilles,
>>>
>>> On 15/12/2012 22:24, Gilles Chanteperdrix wrote:
>>>
>>>> I see some (recent) activity on this git repository:
>>>> https://github.com/siemens/ipipe/commits/core-3.5_for-upstream
>>>>
>>>> In what state is this branch, can I pull from it?
>>> please don't pull yet, I need to port a few more patches forward
>>> and fix one known issue with the tree. But I'll try to send a
>>> pull/discussion request next week.
>>>
>>>> At least the changes allowing preempt_disable()/preempt_enable() to be
>>>> called from non-root context look dubious.
>>> are you referring to 767f0d43fe3? This one still carries a TODO
>>> item in the description to remind me to check with which
>>> non-x86 archs this can cause problems, and what we can do about
>>> them.
>>
>>
>> Actually, we already have ipipe_safe_current(), so I guess what you need
>> is ipipe_safe_current_thread_info() ?
>
> That cannot work unless you patch all the ftrace and perf stack - which
> would surely not be a good idea /wrt maintainability.
>
> The point is remove the instrumentation from preempt_disable/enable at
> least on those archs that do not need it. And then to look at the archs
> that still have stack-based thread_info, if we cannot change this, at
> least for CONFIG_IPIPE enabled.

The problem is the "then", we can not stay with a solution which works 
only for x86_64. The current contents of the github tree which disables 
the ipipe_root_context check on all architectures can not be merged as is.

-- 
					    Gilles.