[PATCH 3.10 005/103] irqchip: Gic: Support forced affinity setting

[PATCH 3.10 005/103] irqchip: Gic: Support forced affinity setting

[Greg Kroah-Hartman]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@linutronix.de>

commit ffde1de64012c406dfdda8690918248b472f24e4 upstream.

To support the affinity setting of per cpu timers in the early startup
of a not yet online cpu, implement the force logic, which disables the
cpu online check.

Tagged for stable to allow a simple fix of the affected SoC clock
event drivers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Tomasz Figa <t.figa@samsung.com>,
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: linux-arm-kernel at lists.infradead.org,
Link: http://lkml.kernel.org/r/20140416143315.916984416 at linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/irqchip/irq-gic.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -246,10 +246,14 @@ static int gic_set_affinity(struct irq_d
 			    bool force)
 {
 	void __iomem *reg = gic_dist_base(d) + GIC_DIST_TARGET + (gic_irq(d) & ~3);
-	unsigned int shift = (gic_irq(d) % 4) * 8;
-	unsigned int cpu = cpumask_any_and(mask_val, cpu_online_mask);
+	unsigned int cpu, shift = (gic_irq(d) % 4) * 8;
 	u32 val, mask, bit;
 
+	if (!force)
+		cpu = cpumask_any_and(mask_val, cpu_online_mask);
+	else
+		cpu = cpumask_first(mask_val);
+
 	if (cpu >= NR_GIC_CPU_IF || cpu >= nr_cpu_ids)
 		return -EINVAL;
 

[PATCH 3.10 006/103] genirq: Allow forcing cpu affinity of interrupts

[Greg Kroah-Hartman]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@linutronix.de>

commit 01f8fa4f01d8362358eb90e412bd7ae18a3ec1ad upstream.

The current implementation of irq_set_affinity() refuses rightfully to
route an interrupt to an offline cpu.

But there is a special case, where this is actually desired. Some of
the ARM SoCs have per cpu timers which require setting the affinity
during cpu startup where the cpu is not yet in the online mask.

If we can't do that, then the local timer interrupt for the about to
become online cpu is routed to some random online cpu.

The developers of the affected machines tried to work around that
issue, but that results in a massive mess in that timer code.

We have a yet unused argument in the set_affinity callbacks of the irq
chips, which I added back then for a similar reason. It was never
required so it got not used. But I'm happy that I never removed it.

That allows us to implement a sane handling of the above scenario. So
the affected SoC drivers can add the required force handling to their
interrupt chip, switch the timer code to irq_force_affinity() and
things just work.

This does not affect any existing user of irq_set_affinity().

Tagged for stable to allow a simple fix of the affected SoC clock
event drivers.

Reported-and-tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Tomasz Figa <t.figa@samsung.com>,
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: linux-arm-kernel at lists.infradead.org,
Link: http://lkml.kernel.org/r/20140416143315.717251504 at linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/cavium-octeon/octeon-irq.c |    2 +-
 include/linux/interrupt.h            |   35 ++++++++++++++++++++++++++++++++++-
 include/linux/irq.h                  |    3 ++-
 kernel/irq/manage.c                  |   17 ++++++-----------
 4 files changed, 43 insertions(+), 14 deletions(-)

--- a/arch/mips/cavium-octeon/octeon-irq.c
+++ b/arch/mips/cavium-octeon/octeon-irq.c
@@ -635,7 +635,7 @@ static void octeon_irq_cpu_offline_ciu(s
 		cpumask_clear(&new_affinity);
 		cpumask_set_cpu(cpumask_first(cpu_online_mask), &new_affinity);
 	}
-	__irq_set_affinity_locked(data, &new_affinity);
+	irq_set_affinity_locked(data, &new_affinity, false);
 }
 
 static int octeon_irq_ciu_set_affinity(struct irq_data *data,
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -239,7 +239,40 @@ static inline int check_wakeup_irqs(void
 
 extern cpumask_var_t irq_default_affinity;
 
-extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask);
+/* Internal implementation. Use the helpers below */
+extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask,
+			      bool force);
+
+/**
+ * irq_set_affinity - Set the irq affinity of a given irq
+ * @irq:	Interrupt to set affinity
+ * @mask:	cpumask
+ *
+ * Fails if cpumask does not contain an online CPU
+ */
+static inline int
+irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	return __irq_set_affinity(irq, cpumask, false);
+}
+
+/**
+ * irq_force_affinity - Force the irq affinity of a given irq
+ * @irq:	Interrupt to set affinity
+ * @mask:	cpumask
+ *
+ * Same as irq_set_affinity, but without checking the mask against
+ * online cpus.
+ *
+ * Solely for low level cpu hotplug code, where we need to make per
+ * cpu interrupts affine before the cpu becomes online.
+ */
+static inline int
+irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	return __irq_set_affinity(irq, cpumask, true);
+}
+
 extern int irq_can_set_affinity(unsigned int irq);
 extern int irq_select_affinity(unsigned int irq);
 
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -375,7 +375,8 @@ extern void remove_percpu_irq(unsigned i
 
 extern void irq_cpu_online(void);
 extern void irq_cpu_offline(void);
-extern int __irq_set_affinity_locked(struct irq_data *data,  const struct cpumask *cpumask);
+extern int irq_set_affinity_locked(struct irq_data *data,
+				   const struct cpumask *cpumask, bool force);
 
 #ifdef CONFIG_GENERIC_HARDIRQS
 
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -150,7 +150,7 @@ int irq_do_set_affinity(struct irq_data
 	struct irq_chip *chip = irq_data_get_irq_chip(data);
 	int ret;
 
-	ret = chip->irq_set_affinity(data, mask, false);
+	ret = chip->irq_set_affinity(data, mask, force);
 	switch (ret) {
 	case IRQ_SET_MASK_OK:
 		cpumask_copy(data->affinity, mask);
@@ -162,7 +162,8 @@ int irq_do_set_affinity(struct irq_data
 	return ret;
 }
 
-int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
+int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
+			    bool force)
 {
 	struct irq_chip *chip = irq_data_get_irq_chip(data);
 	struct irq_desc *desc = irq_data_to_desc(data);
@@ -172,7 +173,7 @@ int __irq_set_affinity_locked(struct irq
 		return -EINVAL;
 
 	if (irq_can_move_pcntxt(data)) {
-		ret = irq_do_set_affinity(data, mask, false);
+		ret = irq_do_set_affinity(data, mask, force);
 	} else {
 		irqd_set_move_pending(data);
 		irq_copy_pending(desc, mask);
@@ -187,13 +188,7 @@ int __irq_set_affinity_locked(struct irq
 	return ret;
 }
 
-/**
- *	irq_set_affinity - Set the irq affinity of a given irq
- *	@irq:		Interrupt to set affinity
- *	@mask:		cpumask
- *
- */
-int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
+int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long flags;
@@ -203,7 +198,7 @@ int irq_set_affinity(unsigned int irq, c
 		return -EINVAL;
 
 	raw_spin_lock_irqsave(&desc->lock, flags);
-	ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
+	ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 	return ret;
 }

[PATCH 3.10 007/103] clocksource: Exynos_mct: Register clock event after request_irq()

[Greg Kroah-Hartman]

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Krzysztof Kozlowski <k.kozlowski@samsung.com>

commit 8db6e5104b77de5d0b7002b95069da0992a34be9 upstream.

After hotplugging CPU1 the first call of interrupt handler for CPU1
oneshot timer was called on CPU0 because it fired before setting IRQ
affinity. Affected are SoCs where Multi Core Timer interrupts are
shared (SPI), e.g. Exynos 4210.

During setup of the MCT timers the clock event device should be
registered after setting the affinity for interrupt. This will prevent
starting the timer too early.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Tomasz Figa <t.figa@samsung.com>,
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: linux-arm-kernel at lists.infradead.org,
Link: http://lkml.kernel.org/r/20140416143316.299247848 at linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/clocksource/exynos_mct.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -429,8 +429,6 @@ static int __cpuinit exynos4_local_timer
 	evt->set_mode = exynos4_tick_set_mode;
 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 	evt->rating = 450;
-	clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
-					0xf, 0x7fffffff);
 
 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 
@@ -448,6 +446,8 @@ static int __cpuinit exynos4_local_timer
 	} else {
 		enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
 	}
+	clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
+					0xf, 0x7fffffff);
 
 	return 0;
 }

[PATCH 3.10 005/103] irqchip: Gic: Support forced affinity setting

[Mark Rutland]

Hi Greg,

On Thu, Jun 05, 2014 at 12:24:28AM +0100, Greg Kroah-Hartman wrote:
> 3.10-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Thomas Gleixner <tglx@linutronix.de>
> 
> commit ffde1de64012c406dfdda8690918248b472f24e4 upstream.
> 
> To support the affinity setting of per cpu timers in the early startup
> of a not yet online cpu, implement the force logic, which disables the
> cpu online check.
> 
> Tagged for stable to allow a simple fix of the affected SoC clock
> event drivers.

This patch alone has the possiblity of breaking CPU hotplug on arm and
arm64 (specifically it breaks hot unplugging CPU0 where interrupts may
be left targetting the offline CPU).

For arm64 [1] that's fixed by commit 601c942176d8 (arm64: use
cpu_online_mask when using forced irq_set_affinity).

Unfortunately there is not an equivalent fix for arm - Russell objected
to the approach [2,3,4], and that's not yet settled.

Mark.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/254836.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/254838.html
[3] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/259245.html
[4] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/259255.html

> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: Tomasz Figa <t.figa@samsung.com>,
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
> Cc: Kukjin Kim <kgene.kim@samsung.com>
> Cc: linux-arm-kernel at lists.infradead.org,
> Link: http://lkml.kernel.org/r/20140416143315.916984416 at linutronix.de
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> ---
>  drivers/irqchip/irq-gic.c |    8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -246,10 +246,14 @@ static int gic_set_affinity(struct irq_d
>  			    bool force)
>  {
>  	void __iomem *reg = gic_dist_base(d) + GIC_DIST_TARGET + (gic_irq(d) & ~3);
> -	unsigned int shift = (gic_irq(d) % 4) * 8;
> -	unsigned int cpu = cpumask_any_and(mask_val, cpu_online_mask);
> +	unsigned int cpu, shift = (gic_irq(d) % 4) * 8;
>  	u32 val, mask, bit;
>  
> +	if (!force)
> +		cpu = cpumask_any_and(mask_val, cpu_online_mask);
> +	else
> +		cpu = cpumask_first(mask_val);
> +
>  	if (cpu >= NR_GIC_CPU_IF || cpu >= nr_cpu_ids)
>  		return -EINVAL;
>  
> 
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

[PATCH 3.10 005/103] irqchip: Gic: Support forced affinity setting

[Greg Kroah-Hartman]

On Thu, Jun 05, 2014 at 05:05:00PM +0100, Mark Rutland wrote:
> Hi Greg,
> 
> On Thu, Jun 05, 2014 at 12:24:28AM +0100, Greg Kroah-Hartman wrote:
> > 3.10-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Thomas Gleixner <tglx@linutronix.de>
> > 
> > commit ffde1de64012c406dfdda8690918248b472f24e4 upstream.
> > 
> > To support the affinity setting of per cpu timers in the early startup
> > of a not yet online cpu, implement the force logic, which disables the
> > cpu online check.
> > 
> > Tagged for stable to allow a simple fix of the affected SoC clock
> > event drivers.
> 
> This patch alone has the possiblity of breaking CPU hotplug on arm and
> arm64 (specifically it breaks hot unplugging CPU0 where interrupts may
> be left targetting the offline CPU).
> 
> For arm64 [1] that's fixed by commit 601c942176d8 (arm64: use
> cpu_online_mask when using forced irq_set_affinity).

Thanks, I'll apply that to the 3.14-stable tree, but, it doesn't seem
relevant at all for 3.10-stable as arch/arm64/kernel/irq.c doesn't do
anything with cpumask or set_affinity.  If it's relevant for 3.10,
please provide a backported version.

> Unfortunately there is not an equivalent fix for arm - Russell objected
> to the approach [2,3,4], and that's not yet settled.

Ok, be sure to cc: stable on the patch when it goes into the tree and
I'll pick it up then.

thanks,

greg k-h

[PATCH 3.10 005/103] irqchip: Gic: Support forced affinity setting

[Mark Rutland]

On Thu, Jun 05, 2014 at 07:05:24PM +0100, Greg Kroah-Hartman wrote:
> On Thu, Jun 05, 2014 at 05:05:00PM +0100, Mark Rutland wrote:
> > Hi Greg,
> > 
> > On Thu, Jun 05, 2014 at 12:24:28AM +0100, Greg Kroah-Hartman wrote:
> > > 3.10-stable review patch.  If anyone has any objections, please let me know.
> > > 
> > > ------------------
> > > 
> > > From: Thomas Gleixner <tglx@linutronix.de>
> > > 
> > > commit ffde1de64012c406dfdda8690918248b472f24e4 upstream.
> > > 
> > > To support the affinity setting of per cpu timers in the early startup
> > > of a not yet online cpu, implement the force logic, which disables the
> > > cpu online check.
> > > 
> > > Tagged for stable to allow a simple fix of the affected SoC clock
> > > event drivers.
> > 
> > This patch alone has the possiblity of breaking CPU hotplug on arm and
> > arm64 (specifically it breaks hot unplugging CPU0 where interrupts may
> > be left targetting the offline CPU).
> > 
> > For arm64 [1] that's fixed by commit 601c942176d8 (arm64: use
> > cpu_online_mask when using forced irq_set_affinity).
> 
> Thanks, I'll apply that to the 3.14-stable tree, but, it doesn't seem
> relevant at all for 3.10-stable as arch/arm64/kernel/irq.c doesn't do
> anything with cpumask or set_affinity.  If it's relevant for 3.10,
> please provide a backported version.

Sorry, my bad. It's not relevant for v3.10, I'd gotten confused over
when I added CPU hotplug.

Thanks,
Mark.

> > Unfortunately there is not an equivalent fix for arm - Russell objected
> > to the approach [2,3,4], and that's not yet settled.
> 
> Ok, be sure to cc: stable on the patch when it goes into the tree and
> I'll pick it up then.
> 
> thanks,
> 
> greg k-h
> 

[PATCH 3.10 005/103] irqchip: Gic: Support forced affinity setting

[Mark Brown]

On Thu, Jun 05, 2014 at 11:05:24AM -0700, Greg Kroah-Hartman wrote:
> On Thu, Jun 05, 2014 at 05:05:00PM +0100, Mark Rutland wrote:

> > This patch alone has the possiblity of breaking CPU hotplug on arm and
> > arm64 (specifically it breaks hot unplugging CPU0 where interrupts may
> > be left targetting the offline CPU).

...

> > Unfortunately there is not an equivalent fix for arm - Russell objected
> > to the approach [2,3,4], and that's not yet settled.

> Ok, be sure to cc: stable on the patch when it goes into the tree and
> I'll pick it up then.

Sadly that fix still hasn't materialised so stable remains broken for
ARM.  The discussion was restarted on Friday but Russell is looking to
Thomas for input.
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