4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Aniruddha Banerjee <aniruddhab@xxxxxxxxxx>
commit aa08192a254d362a4d5317647a81de6996961aef 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.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Aniruddha Banerjee <aniruddhab@xxxxxxxxxx>
[maz: updated changelog]
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/irqchip/irq-gic-common.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/irqchip/irq-gic-common.c
+++ b/drivers/irqchip/irq-gic-common.c
@@ -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,
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);
if (type & IRQ_TYPE_LEVEL_MASK)
val &= ~confmask;
@@ -64,8 +68,10 @@ int gic_configure_irq(unsigned int irq,
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,
pr_warn("GIC: PPI%d is secure or misconfigured\n",
irq - 16);
}
+ raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
if (sync_access)
sync_access();