From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <50D081EB.6080800@xenomai.org> Date: Tue, 18 Dec 2012 15:47:07 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <50CCEA7E.1080000__518.307140055363$1355606686$gmane$org@xenomai.org> <50CCF3B8.5000201@linux-kernel.net> <50CCF6C4.80408@xenomai.org> <50D05218.1080406@web.de> In-Reply-To: <50D05218.1080406@web.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] core-3.5 for x86 List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Wolfgang Mauerer , "Mauerer, Wolfgang" , xenomai@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.