Re: [RFC PATCH] arm: drop Execute-In-Place

Re: [RFC PATCH] arm: drop Execute-In-Place

[Tim Bird]

On 05/05/2011 11:00 AM, Tim Bird wrote:
> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>> nearly no-one use it, only amop1, pxa and sa1100 implement it
> 
> Sony uses this - a lot.  Principally we're using this on a NEC
> naviengine part, which is ARM11MPCore based, support for which
> is (sadly) out of tree.
> 
> I'd like to see MORE support for XIP in the kernel, not less.
> 
> NAK from me.

By the way - it would be good to copy linux-embedded on this,
to expand the discussion.

I should have done that in my response, but I'm doing so now.
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Workgroup of the Linux Foundation
Senior Staff Engineer, Sony Network Entertainment
=============================

Re: [RFC PATCH] arm: drop Execute-In-Place

[David Woodhouse]

On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
> On 05/05/2011 11:00 AM, Tim Bird wrote:
> > On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> >> nearly no-one use it, only amop1, pxa and sa1100 implement it
> > 
> > Sony uses this - a lot.  Principally we're using this on a NEC
> > naviengine part, which is ARM11MPCore based, support for which
> > is (sadly) out of tree. 

If you're out of tree, you don't exist.

-- 
dwmw2

Re: [RFC PATCH] arm: drop Execute-In-Place

[Tim Bird]

On 05/05/2011 11:32 AM, David Woodhouse wrote:
> On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
>> On 05/05/2011 11:00 AM, Tim Bird wrote:
>>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
>>>
>>> Sony uses this - a lot.  Principally we're using this on a NEC
>>> naviengine part, which is ARM11MPCore based, support for which
>>> is (sadly) out of tree. 
> 
> If you're out of tree, you don't exist.

Yeah - I know.  I guess I should tell NEC we'll drop support
for their chip and move to another one that supports XIP
if they don't get their act together.  If XIP survives...
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Workgroup of the Linux Foundation
Senior Staff Engineer, Sony Network Entertainment
=============================

Re: [RFC PATCH] arm: drop Execute-In-Place

[Nicolas Pitre]

On Thu, 5 May 2011, Tim Bird wrote:

> On 05/05/2011 11:32 AM, David Woodhouse wrote:
> > On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
> >> On 05/05/2011 11:00 AM, Tim Bird wrote:
> >>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> >>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
> >>>
> >>> Sony uses this - a lot.  Principally we're using this on a NEC
> >>> naviengine part, which is ARM11MPCore based, support for which
> >>> is (sadly) out of tree. 
> > 
> > If you're out of tree, you don't exist.
> 
> Yeah - I know.  I guess I should tell NEC we'll drop support
> for their chip and move to another one that supports XIP
> if they don't get their act together.  If XIP survives...

It is easy enough to keep it alive... as long as someone uses it of 
course.


Nicolas

Re: [RFC PATCH] arm: drop Execute-In-Place

[Mike Frysinger]

On Thu, May 5, 2011 at 14:54, Nicolas Pitre wrote:
> On Thu, 5 May 2011, Tim Bird wrote:
>> On 05/05/2011 11:32 AM, David Woodhouse wrote:
>> > On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
>> >> On 05/05/2011 11:00 AM, Tim Bird wrote:
>> >>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>> >>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
>> >>>
>> >>> Sony uses this - a lot.  Principally we're using this on a NEC
>> >>> naviengine part, which is ARM11MPCore based, support for which
>> >>> is (sadly) out of tree.
>> >
>> > If you're out of tree, you don't exist.
>>
>> Yeah - I know.  I guess I should tell NEC we'll drop support
>> for their chip and move to another one that supports XIP
>> if they don't get their act together.  If XIP survives...
>
> It is easy enough to keep it alive... as long as someone uses it of
> course.

i think David's point:
... someone <in tree> uses it ...
-mike

Re: [RFC PATCH] arm: drop Execute-In-Place

[Tim Bird]

On 05/05/2011 12:04 PM, Mike Frysinger wrote:
> On Thu, May 5, 2011 at 14:54, Nicolas Pitre wrote:
>> On Thu, 5 May 2011, Tim Bird wrote:
>>> On 05/05/2011 11:32 AM, David Woodhouse wrote:
>>>> On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
>>>>> On 05/05/2011 11:00 AM, Tim Bird wrote:
>>>>>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>>>>>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
>>>>>>
>>>>>> Sony uses this - a lot.  Principally we're using this on a NEC
>>>>>> naviengine part, which is ARM11MPCore based, support for which
>>>>>> is (sadly) out of tree.
>>>>
>>>> If you're out of tree, you don't exist.
>>>
>>> Yeah - I know.  I guess I should tell NEC we'll drop support
>>> for their chip and move to another one that supports XIP
>>> if they don't get their act together.  If XIP survives...
>>
>> It is easy enough to keep it alive... as long as someone uses it of
>> course.
> 
> i think David's point:
> ... someone <in tree> uses it ...

I should add that I tried to use XIP on omap (for research purposes),
but it was broken and I didn't have time to fix it.  My bad.
If anyone is using XIP on in-tree platforms, I'd like to hear
about it.

As for in-tree-ness - I thought the most recent message was to stay
out of tree until the refactoring was over. ;-)
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Workgroup of the Linux Foundation
Senior Staff Engineer, Sony Network Entertainment
=============================

Re: [RFC PATCH] arm: drop Execute-In-Place

[Nicolas Pitre]

On Thu, 5 May 2011, Tim Bird wrote:

> On 05/05/2011 12:04 PM, Mike Frysinger wrote:
> > On Thu, May 5, 2011 at 14:54, Nicolas Pitre wrote:
> >> On Thu, 5 May 2011, Tim Bird wrote:
> >>> On 05/05/2011 11:32 AM, David Woodhouse wrote:
> >>>> On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
> >>>>> On 05/05/2011 11:00 AM, Tim Bird wrote:
> >>>>>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> >>>>>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
> >>>>>>
> >>>>>> Sony uses this - a lot.  Principally we're using this on a NEC
> >>>>>> naviengine part, which is ARM11MPCore based, support for which
> >>>>>> is (sadly) out of tree.
> >>>>
> >>>> If you're out of tree, you don't exist.
> >>>
> >>> Yeah - I know.  I guess I should tell NEC we'll drop support
> >>> for their chip and move to another one that supports XIP
> >>> if they don't get their act together.  If XIP survives...
> >>
> >> It is easy enough to keep it alive... as long as someone uses it of
> >> course.
> > 
> > i think David's point:
> > ... someone <in tree> uses it ...
> 
> I should add that I tried to use XIP on omap (for research purposes),
> but it was broken and I didn't have time to fix it.  My bad.

OMAP is doing pretty nasty things with their early serial port support.  
This is most likely to screw up XIP.

> If anyone is using XIP on in-tree platforms, I'd like to hear
> about it.
> 
> As for in-tree-ness - I thought the most recent message was to stay
> out of tree until the refactoring was over. ;-)

Just to be clear... We have XIP in the tree already.  If it is useful 
to someone, in-tree or out-of-tree, then it is worth keeping around.  
Even if the only user was out-of-tree which certainly wasn't the case 
when I added XIP support to the kernel, then ripping it out and adding 
it back later would be more trouble than preserving it.

What I was asking recently is whether or not XIP is still useful to 
someone today.  Apparently it is, which is the answer I was looking for.


Nicolas

Re: [RFC PATCH] arm: drop Execute-In-Place

[Mike Frysinger]

On Thu, May 5, 2011 at 15:12, Tim Bird wrote:
> On 05/05/2011 12:04 PM, Mike Frysinger wrote:
>> On Thu, May 5, 2011 at 14:54, Nicolas Pitre wrote:
>>> On Thu, 5 May 2011, Tim Bird wrote:
>>>> On 05/05/2011 11:32 AM, David Woodhouse wrote:
>>>>> On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
>>>>>> On 05/05/2011 11:00 AM, Tim Bird wrote:
>>>>>>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>>>>>>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
>>>>>>>
>>>>>>> Sony uses this - a lot.  Principally we're using this on a NEC
>>>>>>> naviengine part, which is ARM11MPCore based, support for which
>>>>>>> is (sadly) out of tree.
>>>>>
>>>>> If you're out of tree, you don't exist.
>>>>
>>>> Yeah - I know.  I guess I should tell NEC we'll drop support
>>>> for their chip and move to another one that supports XIP
>>>> if they don't get their act together.  If XIP survives...
>>>
>>> It is easy enough to keep it alive... as long as someone uses it of
>>> course.
>>
>> i think David's point:
>> ... someone <in tree> uses it ...
>
> I should add that I tried to use XIP on omap (for research purposes),
> but it was broken and I didn't have time to fix it.  My bad.
> If anyone is using XIP on in-tree platforms, I'd like to hear
> about it.

XIP on Blackfin should work right now, but that doesnt directly apply
to the patch in question here.  it does however imply that other
pieces in the stack work (like the MTD/mm layers).

> As for in-tree-ness - I thought the most recent message was to stay
> out of tree until the refactoring was over. ;-)

to be fair, does this have any relevance whatsoever to NEC parts ?
istm that the hindrance here is NEC doing any actual work for
mainline.  even if there was no refactoring, i find it hard to believe
that an NEC port would be posted.  if it were actually something that
could happen, then they should already be posting patches for *basic*
review to get the pieces unrelated to the refactoring worked out.
there's no reason this has to be done serially.
-mike

Re: [RFC PATCH] arm: drop Execute-In-Place

[Vitaly Wool]

On Thu, May 5, 2011 at 9:27 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:

> Just to be clear... We have XIP in the tree already.  If it is useful
> to someone, in-tree or out-of-tree, then it is worth keeping around.
> Even if the only user was out-of-tree which certainly wasn't the case
> when I added XIP support to the kernel, then ripping it out and adding
> it back later would be more trouble than preserving it.
>
> What I was asking recently is whether or not XIP is still useful to
> someone today.  Apparently it is, which is the answer I was looking for.

Surely it is. The last thing I tried was the i.mx deviation which is
very much based on what's in the tree. It didn't work out without some
bits of hackery and I never got it straight enough to try upstreaming.

But nevertheless, IMO XIP is not dead and is not going to be in the
closest future.

~Vitaly

Re: [RFC PATCH] arm: drop Execute-In-Place

[Tim Bird]

On 05/05/2011 12:27 PM, Mike Frysinger wrote:
> On Thu, May 5, 2011 at 15:12, Tim Bird wrote:
>> On 05/05/2011 12:04 PM, Mike Frysinger wrote:
>>> On Thu, May 5, 2011 at 14:54, Nicolas Pitre wrote:
>>>> On Thu, 5 May 2011, Tim Bird wrote:
>>>>> On 05/05/2011 11:32 AM, David Woodhouse wrote:
>>>>>> On Thu, 2011-05-05 at 11:03 -0700, Tim Bird wrote:
>>>>>>> On 05/05/2011 11:00 AM, Tim Bird wrote:
>>>>>>>> On 05/05/2011 07:52 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>>>>>>>>> nearly no-one use it, only amop1, pxa and sa1100 implement it
>>>>>>>>
>>>>>>>> Sony uses this - a lot.  Principally we're using this on a NEC
>>>>>>>> naviengine part, which is ARM11MPCore based, support for which
>>>>>>>> is (sadly) out of tree.
>>>>>>
>>>>>> If you're out of tree, you don't exist.
>>>>>
>>>>> Yeah - I know.  I guess I should tell NEC we'll drop support
>>>>> for their chip and move to another one that supports XIP
>>>>> if they don't get their act together.  If XIP survives...
>>>>
>>>> It is easy enough to keep it alive... as long as someone uses it of
>>>> course.
>>>
>>> i think David's point:
>>> ... someone <in tree> uses it ...
>>
>> I should add that I tried to use XIP on omap (for research purposes),
>> but it was broken and I didn't have time to fix it.  My bad.
>> If anyone is using XIP on in-tree platforms, I'd like to hear
>> about it.
> 
> XIP on Blackfin should work right now, but that doesnt directly apply
> to the patch in question here.  it does however imply that other
> pieces in the stack work (like the MTD/mm layers).
> 
>> As for in-tree-ness - I thought the most recent message was to stay
>> out of tree until the refactoring was over. ;-)
> 
> to be fair, does this have any relevance whatsoever to NEC parts ?
> istm that the hindrance here is NEC doing any actual work for
> mainline.  even if there was no refactoring, i find it hard to believe
> that an NEC port would be posted.  if it were actually something that
> could happen, then they should already be posting patches for *basic*
> review to get the pieces unrelated to the refactoring worked out.
> there's no reason this has to be done serially.

Well, OK.  I just don't want to lob bombs at NEC and then
have some poor soul over there get immediately rebuffed, due to
basic ARM churn.  Maybe not having naviengine support upstream
is my fault, but Sony doesn't make the CPU, so it doesn't seem
like it should be my job to mainline the chip support.  About
the only thing I have at my disposal is pressure not to buy
the chip (but this is harder to exercise than one might think.)
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Workgroup of the Linux Foundation
Senior Staff Engineer, Sony Network Entertainment
=============================

Re: [RFC PATCH] arm: drop Execute-In-Place

[Mike Frysinger]

On Thu, May 5, 2011 at 16:25, Tim Bird wrote:
> On 05/05/2011 12:27 PM, Mike Frysinger wrote:
>> On Thu, May 5, 2011 at 15:12, Tim Bird wrote:
>>> As for in-tree-ness - I thought the most recent message was to stay
>>> out of tree until the refactoring was over. ;-)
>>
>> to be fair, does this have any relevance whatsoever to NEC parts ?
>> istm that the hindrance here is NEC doing any actual work for
>> mainline.  even if there was no refactoring, i find it hard to believe
>> that an NEC port would be posted.  if it were actually something that
>> could happen, then they should already be posting patches for *basic*
>> review to get the pieces unrelated to the refactoring worked out.
>> there's no reason this has to be done serially.
>
> Well, OK.  I just don't want to lob bombs at NEC and then
> have some poor soul over there get immediately rebuffed, due to
> basic ARM churn.  Maybe not having naviengine support upstream
> is my fault, but Sony doesn't make the CPU, so it doesn't seem
> like it should be my job to mainline the chip support.  About
> the only thing I have at my disposal is pressure not to buy
> the chip (but this is harder to exercise than one might think.)

i dont have any vested interest either way wrt NEC or ARM/XIP.  i was
just trying to highlight what i saw as a red herring.

i think the axiom "post early & post often" holds just as true here.
-mike

Re: [RFC PATCH] arm: drop Execute-In-Place

[Jean-Christophe PLAGNIOL-VILLARD]

On 16:31 Thu 05 May     , Mike Frysinger wrote:
> On Thu, May 5, 2011 at 16:25, Tim Bird wrote:
> > On 05/05/2011 12:27 PM, Mike Frysinger wrote:
> >> On Thu, May 5, 2011 at 15:12, Tim Bird wrote:
> >>> As for in-tree-ness - I thought the most recent message was to stay
> >>> out of tree until the refactoring was over. ;-)
> >>
> >> to be fair, does this have any relevance whatsoever to NEC parts ?
> >> istm that the hindrance here is NEC doing any actual work for
> >> mainline.  even if there was no refactoring, i find it hard to believe
> >> that an NEC port would be posted.  if it were actually something that
> >> could happen, then they should already be posting patches for *basic*
> >> review to get the pieces unrelated to the refactoring worked out.
> >> there's no reason this has to be done serially.
> >
> > Well, OK.  I just don't want to lob bombs at NEC and then
> > have some poor soul over there get immediately rebuffed, due to
> > basic ARM churn.  Maybe not having naviengine support upstream
> > is my fault, but Sony doesn't make the CPU, so it doesn't seem
> > like it should be my job to mainline the chip support.  About
> > the only thing I have at my disposal is pressure not to buy
> > the chip (but this is harder to exercise than one might think.)
> 
> i dont have any vested interest either way wrt NEC or ARM/XIP.  i was
> just trying to highlight what i saw as a red herring.
> 
> i think the axiom "post early & post often" holds just as true here.
I've the same felling as Mike or David

Out of tree does not exist

Specially when they do effort to come mainline

Best Regards,
J.

Re: [RFC PATCH] arm: drop Execute-In-Place

[Tony Lindgren]

* Nicolas Pitre <nicolas.pitre@linaro.org> [110505 22:23]:
> On Thu, 5 May 2011, Tim Bird wrote:
> > 
> > I should add that I tried to use XIP on omap (for research purposes),
> > but it was broken and I didn't have time to fix it.  My bad.
> 
> OMAP is doing pretty nasty things with their early serial port support.  
> This is most likely to screw up XIP.

Yes to debug it you'd have to hardcode the uart_phys and virt
in the debug-macro.S for DEBUG_LL and EARLY_PRINTK. But should
be easy enough to do for anybody using XIP.

Of course there may also be other issues too :)

Tony