summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorBarry Song <song.bao.hua@hisilicon.com>2021-03-03 11:49:15 +1300
committerIngo Molnar <mingo@kernel.org>2021-03-06 12:48:00 +0100
commitcbe16f35bee6880becca6f20d2ebf6b457148552 (patch)
tree4c82c004e0be2e9100af1407c11b5f35028a0d48
parenta38fd8748464831584a19438cbb3082b5a2dab15 (diff)
downloadlinux-stable-cbe16f35bee6880becca6f20d2ebf6b457148552.tar.gz
linux-stable-cbe16f35bee6880becca6f20d2ebf6b457148552.tar.bz2
linux-stable-cbe16f35bee6880becca6f20d2ebf6b457148552.zip
genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()
Many drivers don't want interrupts enabled automatically via request_irq(). So they are handling this issue by either way of the below two: (1) irq_set_status_flags(irq, IRQ_NOAUTOEN); request_irq(dev, irq...); (2) request_irq(dev, irq...); disable_irq(irq); The code in the second way is silly and unsafe. In the small time gap between request_irq() and disable_irq(), interrupts can still come. The code in the first way is safe though it's subobtimal. Add a new IRQF_NO_AUTOEN flag which can be handed in by drivers to request_irq() and request_nmi(). It prevents the automatic enabling of the requested interrupt/nmi in the same safe way as #1 above. With that the various usage sites of #1 and #2 above can be simplified and corrected. Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: dmitry.torokhov@gmail.com Link: https://lore.kernel.org/r/20210302224916.13980-2-song.bao.hua@hisilicon.com
-rw-r--r--include/linux/interrupt.h4
-rw-r--r--kernel/irq/manage.c11
2 files changed, 13 insertions, 2 deletions
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 967e25767153..76f1161a441a 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -61,6 +61,9 @@
* interrupt handler after suspending interrupts. For system
* wakeup devices users need to implement wakeup detection in
* their interrupt handlers.
+ * IRQF_NO_AUTOEN - Don't enable IRQ or NMI automatically when users request it.
+ * Users will enable it explicitly by enable_irq() or enable_nmi()
+ * later.
*/
#define IRQF_SHARED 0x00000080
#define IRQF_PROBE_SHARED 0x00000100
@@ -74,6 +77,7 @@
#define IRQF_NO_THREAD 0x00010000
#define IRQF_EARLY_RESUME 0x00020000
#define IRQF_COND_SUSPEND 0x00040000
+#define IRQF_NO_AUTOEN 0x00080000
#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index dec3f73e8db9..97c231a5644c 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1693,7 +1693,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
}
- if (irq_settings_can_autoenable(desc)) {
+ if (!(new->flags & IRQF_NO_AUTOEN) &&
+ irq_settings_can_autoenable(desc)) {
irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
} else {
/*
@@ -2086,10 +2087,15 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
* which interrupt is which (messes up the interrupt freeing
* logic etc).
*
+ * Also shared interrupts do not go well with disabling auto enable.
+ * The sharing interrupt might request it while it's still disabled
+ * and then wait for interrupts forever.
+ *
* Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
* it cannot be set along with IRQF_NO_SUSPEND.
*/
if (((irqflags & IRQF_SHARED) && !dev_id) ||
+ ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
(!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
return -EINVAL;
@@ -2245,7 +2251,8 @@ int request_nmi(unsigned int irq, irq_handler_t handler,
desc = irq_to_desc(irq);
- if (!desc || irq_settings_can_autoenable(desc) ||
+ if (!desc || (irq_settings_can_autoenable(desc) &&
+ !(irqflags & IRQF_NO_AUTOEN)) ||
!irq_settings_can_request(desc) ||
WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
!irq_supports_nmi(desc))