[PATCH v3 02/16] genirq: Allow interrupts to be excluded from /proc/interrupts

Marc Zyngier
2020-09-01T14:44:08Z

A number of architectures implement IPI statistics directly,
duplicating the core kstat_irqs accounting. As we move IPIs to
being actual IRQs, we would end-up with a confusing display
in /proc/interrupts (where the IPIs would appear twice).

In order to solve this, allow interrupts to be flagged as
"hidden", which excludes them from /proc/interrupts.

Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
include/linux/irq.h | 4 +++-
kernel/irq/debugfs.c | 1 +
kernel/irq/proc.c | 2 +-
kernel/irq/settings.h | 7 +++++++
4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 57205bbf46bf..63b9d962ee67 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -71,6 +71,7 @@ enum irqchip_irq_state;
* it from the spurious interrupt detection
* mechanism and from core side polling.
* IRQ_DISABLE_UNLAZY - Disable lazy irq disable
+ * IRQ_HIDDEN - Don't show up in /proc/interrupts
*/
enum {
IRQ_TYPE_NONE = 0x00000000,
@@ -97,13 +98,14 @@ enum {
IRQ_PER_CPU_DEVID = (1 << 17),
IRQ_IS_POLLED = (1 << 18),
IRQ_DISABLE_UNLAZY = (1 << 19),
+ IRQ_HIDDEN = (1 << 20),
};

#define IRQF_MODIFY_MASK \
(IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \
IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \
IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \
- IRQ_IS_POLLED | IRQ_DISABLE_UNLAZY)
+ IRQ_IS_POLLED | IRQ_DISABLE_UNLAZY | IRQ_HIDDEN)

#define IRQ_NO_BALANCING_MASK (IRQ_PER_CPU | IRQ_NO_BALANCING)

diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index b95ff5d5f4bd..acabc0c0e46b 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -136,6 +136,7 @@ static const struct irq_bit_descr irqdesc_states[] = {
BIT_MASK_DESCR(_IRQ_PER_CPU_DEVID),
BIT_MASK_DESCR(_IRQ_IS_POLLED),
BIT_MASK_DESCR(_IRQ_DISABLE_UNLAZY),
+ BIT_MASK_DESCR(_IRQ_HIDDEN),
};

static const struct irq_bit_descr irqdesc_istates[] = {
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 32c071d7bc03..72513ed2a5fc 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -485,7 +485,7 @@ int show_interrupts(struct seq_file *p, void *v)

rcu_read_lock();
desc = irq_to_desc(i);
- if (!desc)
+ if (!desc || irq_settings_is_hidden(desc))
goto outsparse;

if (desc->kstat_irqs)
diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h
index e43795cd2ccf..403378b9947b 100644
--- a/kernel/irq/settings.h
+++ b/kernel/irq/settings.h
@@ -17,6 +17,7 @@ enum {
_IRQ_PER_CPU_DEVID = IRQ_PER_CPU_DEVID,
_IRQ_IS_POLLED = IRQ_IS_POLLED,
_IRQ_DISABLE_UNLAZY = IRQ_DISABLE_UNLAZY,
+ _IRQ_HIDDEN = IRQ_HIDDEN,
_IRQF_MODIFY_MASK = IRQF_MODIFY_MASK,
};

@@ -31,6 +32,7 @@ enum {
#define IRQ_PER_CPU_DEVID GOT_YOU_MORON
#define IRQ_IS_POLLED GOT_YOU_MORON
#define IRQ_DISABLE_UNLAZY GOT_YOU_MORON
+#define IRQ_HIDDEN GOT_YOU_MORON
#undef IRQF_MODIFY_MASK
#define IRQF_MODIFY_MASK GOT_YOU_MORON

@@ -167,3 +169,8 @@ static inline void irq_settings_clr_disable_unlazy(struct irq_desc *desc)
{
desc->status_use_accessors &= ~_IRQ_DISABLE_UNLAZY;
}
+
+static inline bool irq_settings_is_hidden(struct irq_desc *desc)
+{
+ return desc->status_use_accessors & _IRQ_HIDDEN;
+}
--
2.27.0