[PATCH 00/15] arm/arm64: fix use of irq_find_mapping outside of legal RCU context

[PATCH 00/15] arm/arm64: fix use of irq_find_mapping outside of legal RCU context

[Marc Zyngier]

A number of irqchip drivers are directly calling irq_find_mapping,
which may use a rcu_read_lock call when walking the radix tree.

Turns out that if you hit that point with CONFIG_PROVE_RCU enabled,
the kernel will shout at you, as using RCU in this context may be
illegal (specially if coming from the idle state, where RCU would be
in a quiescent state).

A possible fix would be to wrap calls to irq_find_mapping into a
RCU_NONIDLE macro, but that really looks ugly.

This patch series introduce another IRQ entry point on arm and arm64
(handle_domain_irq), which has the exact same behaviour as handle_IRQ,
except that it also takes a irq_domain pointer. This allows the
logical IRQ lookup to be done inside the irq_{enter,exit} section,
which contains a rcu_irq_{enter,exit}, making it safe.

A number of irqchips are then converted to this new entry point. I've
converted all the direct users of irq_find_mapping, except for the
cases where it was used as a chained handler (chained_irq_{enter,exit}
makes it safe). Users of irq_linear_revmap are safe as well.

I've given it some light testing on arm64. The series is also
available in my tree:

git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git handle_domain_irq

Marc Zyngier (15):
  arm64: pass IRQ domain to the core IRQ handler
  ARM: pass IRQ domain to the core IRQ handler
  irqchip: GIC: convert to handle_domain_irq
  irqchip: armada-370-xp: convert to handle_domain_irq
  irqchip: clps711x: convert to handle_domain_irq
  irqchip: mmp: convert to handle_domain_irq
  irqchip: mxs: convert to handle_domain_irq
  irqchip: orion: convert to handle_domain_irq
  irqchip: s3c24xx: convert to handle_domain_irq
  irqchip: sirfsoc: convert to handle_domain_irq
  irqchip: sun4i: convert to handle_domain_irq
  irqchip: versatile-fpga: convert to handle_domain_irq
  irqchip: vic: convert to handle_domain_irq
  irqchip: vt8500: convert to handle_domain_irq
  irqchip: zevio: convert to handle_domain_irq

 arch/arm/include/asm/irq.h           |  2 ++
 arch/arm/kernel/irq.c                | 23 +++++++++++++++++++----
 arch/arm64/include/asm/hardirq.h     |  4 ++++
 arch/arm64/kernel/irq.c              | 23 ++++++++++++++++++++---
 drivers/irqchip/irq-armada-370-xp.c  | 19 ++++++++++---------
 drivers/irqchip/irq-clps711x.c       | 18 +++++++-----------
 drivers/irqchip/irq-gic.c            |  3 +--
 drivers/irqchip/irq-mmp.c            | 10 ++++------
 drivers/irqchip/irq-mxs.c            |  3 +--
 drivers/irqchip/irq-orion.c          |  5 ++---
 drivers/irqchip/irq-s3c24xx.c        |  4 +---
 drivers/irqchip/irq-sirfsoc.c        |  6 ++----
 drivers/irqchip/irq-sun4i.c          |  5 ++---
 drivers/irqchip/irq-versatile-fpga.c |  2 +-
 drivers/irqchip/irq-vic.c            |  2 +-
 drivers/irqchip/irq-vt8500.c         |  5 ++---
 drivers/irqchip/irq-zevio.c          |  3 +--
 17 files changed, 80 insertions(+), 57 deletions(-)

-- 
2.0.0

[PATCH 01/15] arm64: pass IRQ domain to the core IRQ handler

[Marc Zyngier]

Calling irq_find_mapping from outside a irq_{enter,exit} section is
unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
If coming from the idle state, the rcu_read_lock call in irq_find_mapping
will generate an an unpleasant warning:

<quote>
===============================
[ INFO: suspicious RCU usage. ]
3.16.0-rc1+ #135 Not tainted
-------------------------------
include/linux/rcupdate.h:871 rcu_read_lock() used illegally while idle!

other info that might help us debug this:

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
1 lock held by swapper/0/0:
 #0:  (rcu_read_lock){......}, at: [<ffffffc00010206c>]
irq_find_mapping+0x4c/0x198
</quote>

A solution is to add a new handle_domain_irq entry point into
the arm64 code that the interrupt controller code can call.
This new function takes an irq_domain, and calls into irq_find_domain
inside the irq_{enter,exit} block.

Interrupt controllers can then be updated to use the new mechanism.

Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/hardirq.h |  4 ++++
 arch/arm64/kernel/irq.c          | 23 ++++++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h
index 0be6782..fb3e318 100644
--- a/arch/arm64/include/asm/hardirq.h
+++ b/arch/arm64/include/asm/hardirq.h
@@ -49,6 +49,10 @@ static inline void ack_bad_irq(unsigned int irq)
 
 extern void handle_IRQ(unsigned int, struct pt_regs *);
 
+struct irq_domain;
+extern void handle_domain_irq(struct irq_domain *,
+			      unsigned int, struct pt_regs *);
+
 /*
  * No arch-specific IRQ flags.
  */
diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
index 0f08dfd..cb487ad 100644
--- a/arch/arm64/kernel/irq.c
+++ b/arch/arm64/kernel/irq.c
@@ -23,6 +23,7 @@
 
 #include <linux/kernel_stat.h>
 #include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/smp.h>
 #include <linux/init.h>
 #include <linux/irqchip.h>
@@ -45,19 +46,30 @@ int arch_show_interrupts(struct seq_file *p, int prec)
  * not come via this function.  Instead, they should provide their
  * own 'handler'.  Used by platform code implementing C-based 1st
  * level decoding.
+ *
+ * handle_domain_irq does the same thing, but also converts the HW
+ * interrupt number into a logical one using the provided domain. A
+ * NULL domain indicates that this conversion has already been done.
  */
-void handle_IRQ(unsigned int irq, struct pt_regs *regs)
+void handle_domain_irq(struct irq_domain *domain,
+		       unsigned int hwirq, struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
+	unsigned int irq;
 
 	irq_enter();
 
+	if (domain)
+		irq = irq_find_mapping(domain, hwirq);
+	else
+		irq = hwirq;
+
 	/*
 	 * Some hardware gives randomly wrong interrupts.  Rather
 	 * than crashing, do something sensible.
 	 */
-	if (unlikely(irq >= nr_irqs)) {
-		pr_warn_ratelimited("Bad IRQ%u\n", irq);
+	if (unlikely(!irq || irq >= nr_irqs)) {
+		pr_warn_ratelimited("Bad IRQ%u (%u)\n", irq, hwirq);
 		ack_bad_irq(irq);
 	} else {
 		generic_handle_irq(irq);
@@ -67,6 +79,11 @@ void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 	set_irq_regs(old_regs);
 }
 
+void handle_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+	handle_domain_irq(NULL, irq, regs);
+}
+
 void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 {
 	if (handle_arch_irq)
-- 
2.0.0

[PATCH 02/15] ARM: pass IRQ domain to the core IRQ handler

[Marc Zyngier]

Calling irq_find_mapping from outside a irq_{enter,exit} section is
unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
If coming from the idle state, the rcu_read_lock call in irq_find_mapping
will generate an an unpleasant warning.

A solution is to add a new handle_domain_irq entry point into
the arm code that the interrupt controller code can call.
This new function takes an irq_domain, and calls into irq_find_domain
inside the irq_{enter,exit} block.

Interrupt controllers can then be updated to use the new mechanism.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/irq.h |  2 ++
 arch/arm/kernel/irq.c      | 23 +++++++++++++++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h
index 53c15de..8578811 100644
--- a/arch/arm/include/asm/irq.h
+++ b/arch/arm/include/asm/irq.h
@@ -24,10 +24,12 @@
 #ifndef __ASSEMBLY__
 struct irqaction;
 struct pt_regs;
+struct irq_domain;
 extern void migrate_irqs(void);
 
 extern void asm_do_IRQ(unsigned int, struct pt_regs *);
 void handle_IRQ(unsigned int, struct pt_regs *);
+void handle_domain_irq(struct irq_domain *, unsigned int, struct pt_regs *);
 void init_IRQ(void);
 
 #ifdef CONFIG_MULTI_IRQ_HANDLER
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index 2c42576..d6af69f5 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -62,20 +62,30 @@ int arch_show_interrupts(struct seq_file *p, int prec)
  * not come via this function.  Instead, they should provide their
  * own 'handler'.  Used by platform code implementing C-based 1st
  * level decoding.
+ *
+ * handle_domain_irq does the same thing, but also converts the HW
+ * interrupt number into a logical one using the provided domain. A
+ * NULL domain indicates that this conversion has already been done.
  */
-void handle_IRQ(unsigned int irq, struct pt_regs *regs)
+void handle_domain_irq(struct irq_domain *domain,
+		       unsigned int hwirq, struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
+	unsigned int irq;
 
 	irq_enter();
 
+	if (domain)
+		irq = irq_find_mapping(domain, hwirq);
+	else
+		irq = hwirq;
+
 	/*
 	 * Some hardware gives randomly wrong interrupts.  Rather
 	 * than crashing, do something sensible.
 	 */
-	if (unlikely(irq >= nr_irqs)) {
-		if (printk_ratelimit())
-			printk(KERN_WARNING "Bad IRQ%u\n", irq);
+	if (unlikely(!irq || irq >= nr_irqs)) {
+		pr_warn_ratelimited("Bad IRQ%u (%u)\n", irq, hwirq);
 		ack_bad_irq(irq);
 	} else {
 		generic_handle_irq(irq);
@@ -85,6 +95,11 @@ void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 	set_irq_regs(old_regs);
 }
 
+void handle_IRQ(unsigned int irq, struct pt_regs *regs)
+{
+	handle_domain_irq(NULL, irq, regs);
+}
+
 /*
  * asm_do_IRQ is the interface to be used from assembly code.
  */
-- 
2.0.0

[PATCH 03/15] irqchip: GIC: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-gic.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 7e11c9d..f1f09a7 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -294,8 +294,7 @@ static void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
 		irqnr = irqstat & GICC_IAR_INT_ID_MASK;
 
 		if (likely(irqnr > 15 && irqnr < 1021)) {
-			irqnr = irq_find_mapping(gic->domain, irqnr);
-			handle_IRQ(irqnr, regs);
+			handle_domain_irq(gic->domain, irqnr, regs);
 			continue;
 		}
 		if (irqnr < 16) {
-- 
2.0.0

[PATCH 04/15] irqchip: armada-370-xp: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-armada-370-xp.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index 574aba0..47144be 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -393,13 +393,15 @@ static void armada_370_xp_handle_msi_irq(struct pt_regs *regs, bool is_chained)
 		if (!(msimask & BIT(msinr)))
 			continue;
 
-		irq = irq_find_mapping(armada_370_xp_msi_domain,
-				       msinr - 16);
-
-		if (is_chained)
+		if (is_chained) {
+			irq = irq_find_mapping(armada_370_xp_msi_domain,
+					       msinr - 16);
 			generic_handle_irq(irq);
-		else
-			handle_IRQ(irq, regs);
+		} else {
+			irq = msi - 16;
+			handle_domain_irq(armada_370_xp_msi_domain,
+					  irq, regs);
+		}
 	}
 }
 #else
@@ -444,9 +446,8 @@ armada_370_xp_handle_irq(struct pt_regs *regs)
 			break;
 
 		if (irqnr > 1) {
-			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
-					irqnr);
-			handle_IRQ(irqnr, regs);
+			handle_domain_irq(armada_370_xp_mpic_domain,
+					  irqnr, regs);
 			continue;
 		}
 
-- 
2.0.0

[PATCH 05/15] irqchip: clps711x: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-clps711x.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/irqchip/irq-clps711x.c b/drivers/irqchip/irq-clps711x.c
index 33340dc..33127f1 100644
--- a/drivers/irqchip/irq-clps711x.c
+++ b/drivers/irqchip/irq-clps711x.c
@@ -76,24 +76,20 @@ static struct {
 
 static asmlinkage void __exception_irq_entry clps711x_irqh(struct pt_regs *regs)
 {
-	u32 irqnr, irqstat;
+	u32 irqstat;
 
 	do {
 		irqstat = readw_relaxed(clps711x_intc->intmr[0]) &
 			  readw_relaxed(clps711x_intc->intsr[0]);
-		if (irqstat) {
-			irqnr =	irq_find_mapping(clps711x_intc->domain,
-						 fls(irqstat) - 1);
-			handle_IRQ(irqnr, regs);
-		}
+		if (irqstat)
+			handle_domain_irq(clps711x_intc->domain,
+					  fls(irqstat) - 1, regs);
 
 		irqstat = readw_relaxed(clps711x_intc->intmr[1]) &
 			  readw_relaxed(clps711x_intc->intsr[1]);
-		if (irqstat) {
-			irqnr =	irq_find_mapping(clps711x_intc->domain,
-						 fls(irqstat) - 1 + 16);
-			handle_IRQ(irqnr, regs);
-		}
+		if (irqstat)
+			handle_domain_irq(clps711x_intc->domain,
+					  fls(irqstat) - 1 + 16, regs);
 	} while (irqstat);
 }
 
-- 
2.0.0

[PATCH 06/15] irqchip: mmp: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-mmp.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-mmp.c b/drivers/irqchip/irq-mmp.c
index 1c3e2c9..c0da57b 100644
--- a/drivers/irqchip/irq-mmp.c
+++ b/drivers/irqchip/irq-mmp.c
@@ -196,26 +196,24 @@ static struct mmp_intc_conf mmp2_conf = {
 
 static void __exception_irq_entry mmp_handle_irq(struct pt_regs *regs)
 {
-	int irq, hwirq;
+	int hwirq;
 
 	hwirq = readl_relaxed(mmp_icu_base + PJ1_INT_SEL);
 	if (!(hwirq & SEL_INT_PENDING))
 		return;
 	hwirq &= SEL_INT_NUM_MASK;
-	irq = irq_find_mapping(icu_data[0].domain, hwirq);
-	handle_IRQ(irq, regs);
+	handle_domain_irq(icu_data[0].domain, hwirq, regs);
 }
 
 static void __exception_irq_entry mmp2_handle_irq(struct pt_regs *regs)
 {
-	int irq, hwirq;
+	int hwirq;
 
 	hwirq = readl_relaxed(mmp_icu_base + PJ4_INT_SEL);
 	if (!(hwirq & SEL_INT_PENDING))
 		return;
 	hwirq &= SEL_INT_NUM_MASK;
-	irq = irq_find_mapping(icu_data[0].domain, hwirq);
-	handle_IRQ(irq, regs);
+	handle_domain_irq(icu_data[0].domain, hwirq, regs);
 }
 
 /* MMP (ARMv5) */
-- 
2.0.0

[PATCH 07/15] irqchip: mxs: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-mxs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-mxs.c b/drivers/irqchip/irq-mxs.c
index 4044ff2..e4acf1e 100644
--- a/drivers/irqchip/irq-mxs.c
+++ b/drivers/irqchip/irq-mxs.c
@@ -78,8 +78,7 @@ asmlinkage void __exception_irq_entry icoll_handle_irq(struct pt_regs *regs)
 
 	irqnr = __raw_readl(icoll_base + HW_ICOLL_STAT_OFFSET);
 	__raw_writel(irqnr, icoll_base + HW_ICOLL_VECTOR);
-	irqnr = irq_find_mapping(icoll_domain, irqnr);
-	handle_IRQ(irqnr, regs);
+	handle_domain_irq(icoll_domain, irqnr, regs);
 }
 
 static int icoll_irq_domain_map(struct irq_domain *d, unsigned int virq,
-- 
2.0.0

[PATCH 08/15] irqchip: orion: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-orion.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-orion.c b/drivers/irqchip/irq-orion.c
index 34d18b4..ad0c0f6 100644
--- a/drivers/irqchip/irq-orion.c
+++ b/drivers/irqchip/irq-orion.c
@@ -43,9 +43,8 @@ __exception_irq_entry orion_handle_irq(struct pt_regs *regs)
 			gc->mask_cache;
 		while (stat) {
 			u32 hwirq = __fls(stat);
-			u32 irq = irq_find_mapping(orion_irq_domain,
-						   gc->irq_base + hwirq);
-			handle_IRQ(irq, regs);
+			handle_domain_irq(orion_irq_domain,
+					  gc->irq_base + hwirq, regs);
 			stat &= ~(1 << hwirq);
 		}
 	}
-- 
2.0.0

[PATCH 09/15] irqchip: s3c24xx: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-s3c24xx.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-s3c24xx.c b/drivers/irqchip/irq-s3c24xx.c
index 78a6acc..c8d373f 100644
--- a/drivers/irqchip/irq-s3c24xx.c
+++ b/drivers/irqchip/irq-s3c24xx.c
@@ -339,7 +339,6 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
 {
 	int pnd;
 	int offset;
-	int irq;
 
 	pnd = __raw_readl(intc->reg_intpnd);
 	if (!pnd)
@@ -365,8 +364,7 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
 	if (!(pnd & (1 << offset)))
 		offset =  __ffs(pnd);
 
-	irq = irq_find_mapping(intc->domain, intc_offset + offset);
-	handle_IRQ(irq, regs);
+	handle_domain_irq(intc->domain, intc_offset + offset, regs);
 	return true;
 }
 
-- 
2.0.0

[PATCH 10/15] irqchip: sirfsoc: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-sirfsoc.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-sirfsoc.c b/drivers/irqchip/irq-sirfsoc.c
index 5e54f6d..a469355 100644
--- a/drivers/irqchip/irq-sirfsoc.c
+++ b/drivers/irqchip/irq-sirfsoc.c
@@ -50,12 +50,10 @@ sirfsoc_alloc_gc(void __iomem *base, unsigned int irq_start, unsigned int num)
 static void __exception_irq_entry sirfsoc_handle_irq(struct pt_regs *regs)
 {
 	void __iomem *base = sirfsoc_irqdomain->host_data;
-	u32 irqstat, irqnr;
+	u32 irqstat;
 
 	irqstat = readl_relaxed(base + SIRFSOC_INIT_IRQ_ID);
-	irqnr = irq_find_mapping(sirfsoc_irqdomain, irqstat & 0xff);
-
-	handle_IRQ(irqnr, regs);
+	handle_domain_irq(sirfsoc_irqdomain, irqstat & 0xff, regs);
 }
 
 static int __init sirfsoc_irq_init(struct device_node *np,
-- 
2.0.0

[PATCH 11/15] irqchip: sun4i: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-sun4i.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 6fcef4a..64155b6 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -136,7 +136,7 @@ IRQCHIP_DECLARE(allwinner_sun4i_ic, "allwinner,sun4i-a10-ic", sun4i_of_init);
 
 static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
 {
-	u32 irq, hwirq;
+	u32 hwirq;
 
 	/*
 	 * hwirq == 0 can mean one of 3 things:
@@ -154,8 +154,7 @@ static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
 		return;
 
 	do {
-		irq = irq_find_mapping(sun4i_irq_domain, hwirq);
-		handle_IRQ(irq, regs);
+		handle_domain_irq(sun4i_irq_domain, hwirq, regs);
 		hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
 	} while (hwirq != 0);
 }
-- 
2.0.0

[PATCH 12/15] irqchip: versatile-fpga: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-versatile-fpga.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-versatile-fpga.c b/drivers/irqchip/irq-versatile-fpga.c
index 3ae2bb8..73085b7 100644
--- a/drivers/irqchip/irq-versatile-fpga.c
+++ b/drivers/irqchip/irq-versatile-fpga.c
@@ -92,7 +92,7 @@ static int handle_one_fpga(struct fpga_irq_data *f, struct pt_regs *regs)
 
 	while ((status  = readl(f->base + IRQ_STATUS))) {
 		irq = ffs(status) - 1;
-		handle_IRQ(irq_find_mapping(f->domain, irq), regs);
+		handle_domain_irq(f->domain, irq, regs);
 		handled = 1;
 	}
 
-- 
2.0.0

[PATCH 13/15] irqchip: vic: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-vic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-vic.c b/drivers/irqchip/irq-vic.c
index 7d35287..54089de 100644
--- a/drivers/irqchip/irq-vic.c
+++ b/drivers/irqchip/irq-vic.c
@@ -219,7 +219,7 @@ static int handle_one_vic(struct vic_device *vic, struct pt_regs *regs)
 
 	while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) {
 		irq = ffs(stat) - 1;
-		handle_IRQ(irq_find_mapping(vic->domain, irq), regs);
+		handle_domain_irq(vic->domain, irq, regs);
 		handled = 1;
 	}
 
-- 
2.0.0

[PATCH 14/15] irqchip: vt8500: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-vt8500.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-vt8500.c b/drivers/irqchip/irq-vt8500.c
index eb6e91e..b7af816 100644
--- a/drivers/irqchip/irq-vt8500.c
+++ b/drivers/irqchip/irq-vt8500.c
@@ -181,7 +181,7 @@ static struct irq_domain_ops vt8500_irq_domain_ops = {
 static void __exception_irq_entry vt8500_handle_irq(struct pt_regs *regs)
 {
 	u32 stat, i;
-	int irqnr, virq;
+	int irqnr;
 	void __iomem *base;
 
 	/* Loop through each active controller */
@@ -198,8 +198,7 @@ static void __exception_irq_entry vt8500_handle_irq(struct pt_regs *regs)
 				continue;
 		}
 
-		virq = irq_find_mapping(intc[i].domain, irqnr);
-		handle_IRQ(virq, regs);
+		handle_domain_irq(intc[i].domain, irqnr, regs);
 	}
 }
 
-- 
2.0.0

[PATCH 15/15] irqchip: zevio: convert to handle_domain_irq

[Marc Zyngier]

Use the new handle_domain_irq method to handle interrupts.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/irq-zevio.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-zevio.c b/drivers/irqchip/irq-zevio.c
index ceb3a43..1b7c67d 100644
--- a/drivers/irqchip/irq-zevio.c
+++ b/drivers/irqchip/irq-zevio.c
@@ -56,8 +56,7 @@ static void __exception_irq_entry zevio_handle_irq(struct pt_regs *regs)
 
 	while (readl(zevio_irq_io + IO_STATUS)) {
 		irqnr = readl(zevio_irq_io + IO_CURRENT);
-		irqnr = irq_find_mapping(zevio_irq_domain, irqnr);
-		handle_IRQ(irqnr, regs);
+		handle_domain_IRQ(zevio_irq_domain, irqnr, regs);
 	};
 }
 
-- 
2.0.0

Re: [PATCH 00/15] arm/arm64: fix use of irq_find_mapping outside of legal RCU context

[Christopher Covington]

Hi Mark,

On 07/08/2014 09:10 AM, Marc Zyngier wrote:
> A number of irqchip drivers are directly calling irq_find_mapping,
> which may use a rcu_read_lock call when walking the radix tree.

If this happens to be easy for you to determine: do direct callers of
irq_find_host such as irq_create_of_mapping have a similar problem with
irq_domain_mutex?

Thanks,
Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.

Re: [PATCH 11/15] irqchip: sun4i: convert to handle_domain_irq

[Antoine Ténart]

Hi Marc,

On Tue, Jul 08, 2014 at 02:10:34PM +0100, Marc Zyngier wrote:
> Use the new handle_domain_irq method to handle interrupts.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

I tested this one on an A13 olinuxino. It worked well. I also tested
with CONFIG_PROVE_RCU enabled.

Antoine

> ---
>  drivers/irqchip/irq-sun4i.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
> index 6fcef4a..64155b6 100644
> --- a/drivers/irqchip/irq-sun4i.c
> +++ b/drivers/irqchip/irq-sun4i.c
> @@ -136,7 +136,7 @@ IRQCHIP_DECLARE(allwinner_sun4i_ic, "allwinner,sun4i-a10-ic", sun4i_of_init);
>  
>  static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
>  {
> -	u32 irq, hwirq;
> +	u32 hwirq;
>  
>  	/*
>  	 * hwirq == 0 can mean one of 3 things:
> @@ -154,8 +154,7 @@ static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
>  		return;
>  
>  	do {
> -		irq = irq_find_mapping(sun4i_irq_domain, hwirq);
> -		handle_IRQ(irq, regs);
> +		handle_domain_irq(sun4i_irq_domain, hwirq, regs);
>  		hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
>  	} while (hwirq != 0);
>  }
> -- 
> 2.0.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
Antoine Ténart, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

Re: [PATCH 00/15] arm/arm64: fix use of irq_find_mapping outside of legal RCU context

[Marc Zyngier]

On Fri, Jul 11 2014 at  9:38:22 pm BST, Christopher Covington <cov@codeaurora.org> wrote:
> Hi Mark,
>
> On 07/08/2014 09:10 AM, Marc Zyngier wrote:
>> A number of irqchip drivers are directly calling irq_find_mapping,
>> which may use a rcu_read_lock call when walking the radix tree.
>
> If this happens to be easy for you to determine: do direct callers of
> irq_find_host such as irq_create_of_mapping have a similar problem with
> irq_domain_mutex?

Definitely not from this problem. irq_find_host doesn't use RCU at all,
so it shouldn't be an issue.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny.

Re: [PATCH 02/15] ARM: pass IRQ domain to the core IRQ handler

[Russell King - ARM Linux]

On Tue, Jul 08, 2014 at 02:10:25PM +0100, Marc Zyngier wrote:
> Calling irq_find_mapping from outside a irq_{enter,exit} section is
> unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
> If coming from the idle state, the rcu_read_lock call in irq_find_mapping
> will generate an an unpleasant warning.
> 
> A solution is to add a new handle_domain_irq entry point into
> the arm code that the interrupt controller code can call.
> This new function takes an irq_domain, and calls into irq_find_domain
> inside the irq_{enter,exit} block.
> 
> Interrupt controllers can then be updated to use the new mechanism.

I merged this last night, and this says it all...

Subject: rmk build: 244 warnings 49 failures (rmk/v3.16-rc3-70-gc1ed1df)

arch/arm/kernel/irq.c:81:3: error: implicit declaration of function 'irq_find_mapping' [-Werror=implicit-function-declaration]

So I'm dropping it.

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH 02/15] ARM: pass IRQ domain to the core IRQ handler

[Marc Zyngier]

Hi Russell,

On Sat, Aug 02 2014 at  8:51:18 am BST, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:
> On Tue, Jul 08, 2014 at 02:10:25PM +0100, Marc Zyngier wrote:
>> Calling irq_find_mapping from outside a irq_{enter,exit} section is
>> unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
>> If coming from the idle state, the rcu_read_lock call in irq_find_mapping
>> will generate an an unpleasant warning.
>> 
>> A solution is to add a new handle_domain_irq entry point into
>> the arm code that the interrupt controller code can call.
>> This new function takes an irq_domain, and calls into irq_find_domain
>> inside the irq_{enter,exit} block.
>> 
>> Interrupt controllers can then be updated to use the new mechanism.
>
> I merged this last night, and this says it all...
>
> Subject: rmk build: 244 warnings 49 failures (rmk/v3.16-rc3-70-gc1ed1df)
>
> arch/arm/kernel/irq.c:81:3: error: implicit declaration of function 'irq_find_mapping' [-Werror=implicit-function-declaration]
>
> So I'm dropping it.

Ouch. Sorry about that. Seems like I only tested this with a config that
has CONFIG_IRQ_DOMAIN set. I'll respin in after the merge window.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny.