[Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Jan Kiszka]

The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:

  ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)

are available in the git repository at:
  git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch

[edited log]
Jan Kiszka (4):
      ipipe: Provide wrapper for IRQ mask/unmask at chip level
      ipipe: Drop spurious irq_enter/exit from __ipipe_sync_stage
      ipipe: Provide __ipipe_spin_trylock_irq for !CONFIG_IPIPE
      Merge commit 'v2.6.35.9' into queues/2.6.35-noarch

Will follow up with the ipipe specific patches for review.

[Adeos-main] [PATCH 1/3] ipipe: Provide wrapper for IRQ mask/unmask at chip level

[Jan Kiszka]

We need to overload these services for irqchips that cannot be hardened
to work from arbitrary contexts.

Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
---

I'm still lagging behind with making use of this for MSI masking or
refactoring the Xenomai HAL to use it, but it's a start.

 include/linux/ipipe.h      |   22 ++++++++++++++++++++++
 include/linux/ipipe_base.h |    1 +
 include/linux/irq.h        |    2 ++
 kernel/ipipe/core.c        |    6 ++++++
 4 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/include/linux/ipipe.h b/include/linux/ipipe.h
index 854f132..da2bd68 100644
--- a/include/linux/ipipe.h
+++ b/include/linux/ipipe.h
@@ -28,6 +28,7 @@
 #include <linux/mutex.h>
 #include <linux/linkage.h>
 #include <linux/ipipe_base.h>
+#include <linux/irq.h>
 #include <asm/ipipe.h>
 #include <asm/bug.h>
 
@@ -440,6 +441,27 @@ int ipipe_control_irq(struct ipipe_domain *ipd,
 		      unsigned clrmask,
 		      unsigned setmask);
 
+static inline void ipipe_irq_chip_mask(unsigned int irq, struct irq_desc *desc)
+{
+	desc->ipipe_mask(irq);
+}
+
+static inline void
+ipipe_irq_chip_unmask(unsigned int irq, struct irq_desc *desc)
+{
+	desc->ipipe_unmask(irq);
+}
+
+void __ipipe_irq_chip_nop(unsigned int irq);
+
+#ifndef HAVE_IPIPE_IRQ_DESC_SET_HANDLERS
+static inline void ipipe_irq_desc_set_handlers(struct irq_desc *desc)
+{
+	desc->ipipe_mask = desc->chip->mask ? : __ipipe_irq_chip_nop;
+	desc->ipipe_unmask = desc->chip->unmask ? : __ipipe_irq_chip_nop;
+}
+#endif
+
 unsigned ipipe_alloc_virq(void);
 
 int ipipe_free_virq(unsigned virq);
diff --git a/include/linux/ipipe_base.h b/include/linux/ipipe_base.h
index 3f43ba5..7152485 100644
--- a/include/linux/ipipe_base.h
+++ b/include/linux/ipipe_base.h
@@ -110,6 +110,7 @@ static inline void ipipe_check_context(struct ipipe_domain *border_ipd) { }
 #define __IPIPE_FEATURE_PREPARE_PANIC		1
 #define __IPIPE_FEATURE_ROOT_PREEMPT_NOTIFIER	1
 #define __IPIPE_FEATURE_CONTROL_IRQ		1
+#define __IPIPE_FEATURE_IRQ_CHIP_MASK		1
 
 #else /* !CONFIG_IPIPE */
 
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 630e995..a6969d6 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -181,6 +181,8 @@ struct irq_desc {
 					     struct irq_desc *desc);
 	void			(*ipipe_end)(unsigned int irq,
 					     struct irq_desc *desc);
+	void			(*ipipe_mask)(unsigned int irq);
+	void			(*ipipe_unmask)(unsigned int irq);
 #endif /* CONFIG_IPIPE */
 	unsigned int		irq;
 	struct timer_rand_state *timer_rand_state;
diff --git a/kernel/ipipe/core.c b/kernel/ipipe/core.c
index 9d025b2..756ad02 100644
--- a/kernel/ipipe/core.c
+++ b/kernel/ipipe/core.c
@@ -889,6 +889,10 @@ unsigned ipipe_alloc_virq(void)
 	return irq;
 }
 
+void __ipipe_irq_chip_nop(unsigned int irq)
+{
+}
+
 /*
  * ipipe_virtualize_irq() -- Set a per-domain pipelined interrupt
  * handler.
@@ -981,6 +985,8 @@ int ipipe_virtualize_irq(struct ipipe_domain *ipd,
 	if (desc == NULL)
 		goto unlock_and_exit;
 
+	ipipe_irq_desc_set_handlers(desc);
+
 	if (irq < NR_IRQS && !ipipe_virtual_irq_p(irq)) {
 		__ipipe_enable_irqdesc(ipd, irq);
 		/*

[Adeos-main] [PATCH 2/3] ipipe: Drop spurious irq_enter/exit from __ipipe_sync_stage

[Jan Kiszka]

Invoking irq_enter/exit for root vIRQs is arch business (at least x86
needs to interleave it with exit code).

Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
---
 kernel/ipipe/core.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/ipipe/core.c b/kernel/ipipe/core.c
index 756ad02..129113b 100644
--- a/kernel/ipipe/core.c
+++ b/kernel/ipipe/core.c
@@ -1240,11 +1240,9 @@ void __ipipe_sync_stage(void)
 		if (likely(ipd != ipipe_root_domain)) {
 			ipd->irqs[irq].handler(irq, ipd->irqs[irq].cookie);
 			__ipipe_run_irqtail(irq);
-		} else if (ipipe_virtual_irq_p(irq)) {
-			irq_enter();
+		} else if (ipipe_virtual_irq_p(irq))
 			__ipipe_do_root_virq(ipd, irq);
-			irq_exit();
-		} else
+		else
 			__ipipe_do_root_xirq(ipd, irq);
 
 		local_irq_disable_hw();
-- 
1.7.1

[Adeos-main] [PATCH 3/3] ipipe: Provide __ipipe_spin_trylock_irq for !CONFIG_IPIPE

[Jan Kiszka]

Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
---
 include/linux/ipipe_lock.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/include/linux/ipipe_lock.h b/include/linux/ipipe_lock.h
index 75bf0e8..5382208 100644
--- a/include/linux/ipipe_lock.h
+++ b/include/linux/ipipe_lock.h
@@ -224,6 +224,7 @@ void __ipipe_spin_unlock_debug(unsigned long flags);
 #define __ipipe_spin_lock_irq(lock)		do { } while (0)
 #define __ipipe_spin_unlock_irq(lock)		do { } while (0)
 #define __ipipe_spin_lock_irqsave(lock)		0
+#define __ipipe_spin_trylock_irq(lock)		1
 #define __ipipe_spin_trylock_irqsave(lock, x)	({ (void)(x); 1; })
 #define __ipipe_spin_unlock_irqrestore(lock, x)	do { (void)(x); } while (0)
 #define __ipipe_spin_unlock_irqbegin(lock)	do { } while (0)
-- 
1.7.1

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Philippe Gerum]

On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
> 
>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
> 
> are available in the git repository at:
>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
> 
> [edited log]
> Jan Kiszka (4):
>       ipipe: Provide wrapper for IRQ mask/unmask at chip level

Could you give me some hints about the intended usage of these?

>       ipipe: Drop spurious irq_enter/exit from __ipipe_sync_stage

Actually, what is wrong is not with irq_enter/exit, but rather with the
fact that we should only attempt a preemption resched when a virq
handler returns, and that is a generic operation. There is no point in
having uselessly hairy code in the arch-dep section, and that code is
pure nop with CONFIG_PREEMPT off.

I just merged something along these lines.

>       ipipe: Provide __ipipe_spin_trylock_irq for !CONFIG_IPIPE
>       Merge commit 'v2.6.35.9' into queues/2.6.35-noarch
> 
> Will follow up with the ipipe specific patches for review.

I'll be merging the IRQ virtualization removal for x86_32 next, but I
want to issue an intermediate patch with the pending fixes first, given
the potential for regression there is when messing with entry.S.
However, I'll merge the EFLAGS fixes early on, since they are obviously
required and right, and merge them along with 2.8-03 asap.

-- 
Philippe.

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Jan Kiszka]

On 2011-01-18 18:13, Philippe Gerum wrote:
> On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
>> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
>>
>>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
>>
>> are available in the git repository at:
>>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
>>
>> [edited log]
>> Jan Kiszka (4):
>>       ipipe: Provide wrapper for IRQ mask/unmask at chip level
> 
> Could you give me some hints about the intended usage of these?

The idea was (and still is but effort stalled ATM) to emulate MSI
masking on top of that.

> 
>>       ipipe: Drop spurious irq_enter/exit from __ipipe_sync_stage
> 
> Actually, what is wrong is not with irq_enter/exit, but rather with the
> fact that we should only attempt a preemption resched when a virq
> handler returns, and that is a generic operation. There is no point in
> having uselessly hairy code in the arch-dep section, and that code is
> pure nop with CONFIG_PREEMPT off.
> 
> I just merged something along these lines.

OK, will have a look.

> 
>>       ipipe: Provide __ipipe_spin_trylock_irq for !CONFIG_IPIPE
>>       Merge commit 'v2.6.35.9' into queues/2.6.35-noarch
>>
>> Will follow up with the ipipe specific patches for review.
> 
> I'll be merging the IRQ virtualization removal for x86_32 next, but I
> want to issue an intermediate patch with the pending fixes first, given
> the potential for regression there is when messing with entry.S.
> However, I'll merge the EFLAGS fixes early on, since they are obviously
> required and right, and merge them along with 2.8-03 asap.
> 

Fine with me.

Thanks,
Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Philippe Gerum]

On Tue, 2011-01-18 at 18:22 +0100, Jan Kiszka wrote:
> On 2011-01-18 18:13, Philippe Gerum wrote:
> > On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
> >> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
> >>
> >>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
> >>
> >> are available in the git repository at:
> >>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
> >>
> >> [edited log]
> >> Jan Kiszka (4):
> >>       ipipe: Provide wrapper for IRQ mask/unmask at chip level
> > 
> > Could you give me some hints about the intended usage of these?
> 
> The idea was (and still is but effort stalled ATM) to emulate MSI
> masking on top of that.

Ok, let's keep this on the shelf until we come with a complete solution.
I suspect we will have to resync the Xenomai and I-pipe interfaces to
this end.

> 
> > 
> >>       ipipe: Drop spurious irq_enter/exit from __ipipe_sync_stage
> > 
> > Actually, what is wrong is not with irq_enter/exit, but rather with the
> > fact that we should only attempt a preemption resched when a virq
> > handler returns, and that is a generic operation. There is no point in
> > having uselessly hairy code in the arch-dep section, and that code is
> > pure nop with CONFIG_PREEMPT off.
> > 
> > I just merged something along these lines.
> 
> OK, will have a look.
> 
> > 
> >>       ipipe: Provide __ipipe_spin_trylock_irq for !CONFIG_IPIPE
> >>       Merge commit 'v2.6.35.9' into queues/2.6.35-noarch
> >>
> >> Will follow up with the ipipe specific patches for review.
> > 
> > I'll be merging the IRQ virtualization removal for x86_32 next, but I
> > want to issue an intermediate patch with the pending fixes first, given
> > the potential for regression there is when messing with entry.S.
> > However, I'll merge the EFLAGS fixes early on, since they are obviously
> > required and right, and merge them along with 2.8-03 asap.
> > 
> 
> Fine with me.
> 
> Thanks,
> Jan
> 

-- 
Philippe.

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Jan Kiszka]

On 2011-01-18 18:27, Philippe Gerum wrote:
> On Tue, 2011-01-18 at 18:22 +0100, Jan Kiszka wrote:
>> On 2011-01-18 18:13, Philippe Gerum wrote:
>>> On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
>>>> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
>>>>
>>>>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
>>>>
>>>> are available in the git repository at:
>>>>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
>>>>
>>>> [edited log]
>>>> Jan Kiszka (4):
>>>>       ipipe: Provide wrapper for IRQ mask/unmask at chip level
>>>
>>> Could you give me some hints about the intended usage of these?
>>
>> The idea was (and still is but effort stalled ATM) to emulate MSI
>> masking on top of that.
> 
> Ok, let's keep this on the shelf until we come with a complete solution.
> I suspect we will have to resync the Xenomai and I-pipe interfaces to
> this end.

Definitely. So the patch was intended as a starting point, enbling
refactoring on Xenomai side. Quite a lot of work is actually to be done
on the rthal, also to clean up lots of duplicate irq descriptor
translations over there.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Gilles Chanteperdrix]

Jan Kiszka wrote:
> On 2011-01-18 18:27, Philippe Gerum wrote:
>> On Tue, 2011-01-18 at 18:22 +0100, Jan Kiszka wrote:
>>> On 2011-01-18 18:13, Philippe Gerum wrote:
>>>> On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
>>>>> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
>>>>>
>>>>>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
>>>>>
>>>>> are available in the git repository at:
>>>>>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
>>>>>
>>>>> [edited log]
>>>>> Jan Kiszka (4):
>>>>>       ipipe: Provide wrapper for IRQ mask/unmask at chip level
>>>> Could you give me some hints about the intended usage of these?
>>> The idea was (and still is but effort stalled ATM) to emulate MSI
>>> masking on top of that.
>> Ok, let's keep this on the shelf until we come with a complete solution.
>> I suspect we will have to resync the Xenomai and I-pipe interfaces to
>> this end.
> 
> Definitely. So the patch was intended as a starting point, enbling
> refactoring on Xenomai side. Quite a lot of work is actually to be done
> on the rthal, also to clean up lots of duplicate irq descriptor
> translations over there.

As a maintainer of low end architectures, I am not too fond with
introducing one more level of function pointers. A substantial part of
the worst case interrupt latency on ARM is spent in these routines, so,
it would be nice if we could avoid make this even longer. And still on
ARM, acking/masking an interrupt line is just about writing some bit to
some MMIO memory, so, the cost of the function pointer is definitely not
negligible.

-- 
                                                                Gilles.

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Jan Kiszka]

On 2011-01-18 18:37, Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> On 2011-01-18 18:27, Philippe Gerum wrote:
>>> On Tue, 2011-01-18 at 18:22 +0100, Jan Kiszka wrote:
>>>> On 2011-01-18 18:13, Philippe Gerum wrote:
>>>>> On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
>>>>>> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
>>>>>>
>>>>>>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
>>>>>>
>>>>>> are available in the git repository at:
>>>>>>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
>>>>>>
>>>>>> [edited log]
>>>>>> Jan Kiszka (4):
>>>>>>       ipipe: Provide wrapper for IRQ mask/unmask at chip level
>>>>> Could you give me some hints about the intended usage of these?
>>>> The idea was (and still is but effort stalled ATM) to emulate MSI
>>>> masking on top of that.
>>> Ok, let's keep this on the shelf until we come with a complete solution.
>>> I suspect we will have to resync the Xenomai and I-pipe interfaces to
>>> this end.
>>
>> Definitely. So the patch was intended as a starting point, enbling
>> refactoring on Xenomai side. Quite a lot of work is actually to be done
>> on the rthal, also to clean up lots of duplicate irq descriptor
>> translations over there.
> 
> As a maintainer of low end architectures, I am not too fond with
> introducing one more level of function pointers. A substantial part of
> the worst case interrupt latency on ARM is spent in these routines, so,
> it would be nice if we could avoid make this even longer. And still on
> ARM, acking/masking an interrupt line is just about writing some bit to
> some MMIO memory, so, the cost of the function pointer is definitely not
> negligible.

Then we need to push the definition of ipipe_irq_chip_[un]mask into arch
hands and effectively keep it for those setups as is which do not need
more. But we do need this abstraction.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Philippe Gerum]

On Tue, 2011-01-18 at 18:13 +0100, Philippe Gerum wrote:
> On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
> > The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
> > 
> >   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
> > 
> > are available in the git repository at:
> >   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
> > 
> > [edited log]
> > Jan Kiszka (4):
> >       ipipe: Provide wrapper for IRQ mask/unmask at chip level
> 
> Could you give me some hints about the intended usage of these?
> 
> >       ipipe: Drop spurious irq_enter/exit from __ipipe_sync_stage
> 
> Actually, what is wrong is not with irq_enter/exit, but rather with the
> fact that we should only attempt a preemption resched when a virq
> handler returns, and that is a generic operation. There is no point in
> having uselessly hairy code in the arch-dep section, and that code is
> pure nop with CONFIG_PREEMPT off.
> 
> I just merged something along these lines.
> 
> >       ipipe: Provide __ipipe_spin_trylock_irq for !CONFIG_IPIPE
> >       Merge commit 'v2.6.35.9' into queues/2.6.35-noarch
> > 
> > Will follow up with the ipipe specific patches for review.
> 
> I'll be merging the IRQ virtualization removal for x86_32 next, but I
> want to issue an intermediate patch with the pending fixes first, given
> the potential for regression there is when messing with entry.S.
> However, I'll merge the EFLAGS fixes early on, since they are obviously
> required and right, and merge them along with 2.8-03 asap.
> 

Actually, my latest patch is crap. 2.8-03 introduces a regression w/
CONFIG_PREEMPT. I'll revert this and provide a better approach.

-- 
Philippe.