Commit 439e8b2d authored by Aniruddha Banerjee's avatar Aniruddha Banerjee Committed by Greg Kroah-Hartman

irqchip/gic: Take lock when updating irq type

commit aa08192a upstream.

Most MMIO GIC register accesses use a 1-hot bit scheme that
avoids requiring any form of locking. This isn't true for the
GICD_ICFGRn registers, which require a RMW sequence.

Unfortunately, we seem to be missing a lock for these particular
accesses, which could result in a race condition if changing the
trigger type on any two interrupts within the same set of 16
interrupts (and thus controlled by the same CFGR register).

Introduce a private lock in the GIC common comde for this
particular case, making it cover both GIC implementations
in one go.

Signed-off-by: default avatarAniruddha Banerjee <>
[maz: updated changelog]
Signed-off-by: default avatarMarc Zyngier <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 28363778
......@@ -21,6 +21,8 @@
#include "irq-gic-common.h"
static DEFINE_RAW_SPINLOCK(irq_controller_lock);
static const struct gic_kvm_info *gic_kvm_info;
const struct gic_kvm_info *gic_get_kvm_info(void)
......@@ -52,11 +54,13 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
u32 confoff = (irq / 16) * 4;
u32 val, oldval;
int ret = 0;
unsigned long flags;
* Read current configuration register, and insert the config
* for "irq", depending on "type".
raw_spin_lock_irqsave(&irq_controller_lock, flags);
val = oldval = readl_relaxed(base + GIC_DIST_CONFIG + confoff);
val &= ~confmask;
......@@ -64,8 +68,10 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
val |= confmask;
/* If the current configuration is the same, then we are done */
if (val == oldval)
if (val == oldval) {
raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
return 0;
* Write back the new configuration, and possibly re-enable
......@@ -83,6 +89,7 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
pr_warn("GIC: PPI%d is secure or misconfigured\n",
irq - 16);
raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
if (sync_access)
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