genirq: Export affinity setter for modules

mainline inclusion
from mainline-v5.13-rc3
commit 4d80d6ca
category: bugfix
bugzilla: 175148
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4d80d6ca5d77fde9880da8466e5b64f250e5bf82

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

Perf modules abuse irq_set_affinity_hint() to set the affinity of system
PMU interrupts just because irq_set_affinity() was not exported.

The fact that irq_set_affinity_hint() actually sets the affinity is a
non-documented side effect and the name is clearly saying it's a hint.

To clean this up, export the real affinity setter.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210518093117.968251441@linutronix.deReviewed-by: NShaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/interrupt.h

@@ -314,39 +314,8 @@ struct irq_affinity_desc {
 
 extern cpumask_var_t irq_default_affinity;
 
-/* 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
- * @cpumask:	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
- * @cpumask:	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_set_affinity(unsigned int irq, const struct cpumask *cpumask);
+extern int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask);
 
 extern int irq_can_set_affinity(unsigned int irq);
 extern int irq_select_affinity(unsigned int irq);

kernel/irq/manage.c

@@ -371,7 +371,8 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
 	return ret;
 }
 
-int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
+static int __irq_set_affinity(unsigned int irq, const struct cpumask *mask,
+			      bool force)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long flags;
@@ -386,6 +387,36 @@ int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
 	return ret;
 }
 
+/**
+ * irq_set_affinity - Set the irq affinity of a given irq
+ * @irq:	Interrupt to set affinity
+ * @cpumask:	cpumask
+ *
+ * Fails if cpumask does not contain an online CPU
+ */
+int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	return __irq_set_affinity(irq, cpumask, false);
+}
+EXPORT_SYMBOL_GPL(irq_set_affinity);
+
+/**
+ * irq_force_affinity - Force the irq affinity of a given irq
+ * @irq:	Interrupt to set affinity
+ * @cpumask:	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.
+ */
+int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
+{
+	return __irq_set_affinity(irq, cpumask, true);
+}
+EXPORT_SYMBOL_GPL(irq_force_affinity);
+
 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 {
 	unsigned long flags;