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-rw-r--r--drivers/irqchip/irq-gic-v3-its.c56
-rw-r--r--include/linux/irqchip/arm-gic-v4.h5
2 files changed, 53 insertions, 8 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index da883a691028..1af713990123 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -239,15 +239,41 @@ static struct its_vlpi_map *get_vlpi_map(struct irq_data *d)
return NULL;
}
-static int irq_to_cpuid(struct irq_data *d)
+static int vpe_to_cpuid_lock(struct its_vpe *vpe, unsigned long *flags)
+{
+ raw_spin_lock_irqsave(&vpe->vpe_lock, *flags);
+ return vpe->col_idx;
+}
+
+static void vpe_to_cpuid_unlock(struct its_vpe *vpe, unsigned long flags)
+{
+ raw_spin_unlock_irqrestore(&vpe->vpe_lock, flags);
+}
+
+static int irq_to_cpuid_lock(struct irq_data *d, unsigned long *flags)
{
- struct its_device *its_dev = irq_data_get_irq_chip_data(d);
struct its_vlpi_map *map = get_vlpi_map(d);
+ int cpu;
- if (map)
- return map->vpe->col_idx;
+ if (map) {
+ cpu = vpe_to_cpuid_lock(map->vpe, flags);
+ } else {
+ /* Physical LPIs are already locked via the irq_desc lock */
+ struct its_device *its_dev = irq_data_get_irq_chip_data(d);
+ cpu = its_dev->event_map.col_map[its_get_event_id(d)];
+ /* Keep GCC quiet... */
+ *flags = 0;
+ }
- return its_dev->event_map.col_map[its_get_event_id(d)];
+ return cpu;
+}
+
+static void irq_to_cpuid_unlock(struct irq_data *d, unsigned long flags)
+{
+ struct its_vlpi_map *map = get_vlpi_map(d);
+
+ if (map)
+ vpe_to_cpuid_unlock(map->vpe, flags);
}
static struct its_collection *valid_col(struct its_collection *col)
@@ -1329,7 +1355,9 @@ static void direct_lpi_inv(struct irq_data *d)
{
struct its_vlpi_map *map = get_vlpi_map(d);
void __iomem *rdbase;
+ unsigned long flags;
u64 val;
+ int cpu;
if (map) {
struct its_device *its_dev = irq_data_get_irq_chip_data(d);
@@ -1344,10 +1372,12 @@ static void direct_lpi_inv(struct irq_data *d)
}
/* Target the redistributor this LPI is currently routed to */
- rdbase = per_cpu_ptr(gic_rdists->rdist, irq_to_cpuid(d))->rd_base;
+ cpu = irq_to_cpuid_lock(d, &flags);
+ rdbase = per_cpu_ptr(gic_rdists->rdist, cpu)->rd_base;
gic_write_lpir(val, rdbase + GICR_INVLPIR);
wait_for_syncr(rdbase);
+ irq_to_cpuid_unlock(d, flags);
}
static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
@@ -3486,17 +3516,25 @@ static int its_vpe_set_affinity(struct irq_data *d,
{
struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
int from, cpu = cpumask_first(mask_val);
+ unsigned long flags;
/*
* Changing affinity is mega expensive, so let's be as lazy as
* we can and only do it if we really have to. Also, if mapped
* into the proxy device, we need to move the doorbell
* interrupt to its new location.
+ *
+ * Another thing is that changing the affinity of a vPE affects
+ * *other interrupts* such as all the vLPIs that are routed to
+ * this vPE. This means that the irq_desc lock is not enough to
+ * protect us, and that we must ensure nobody samples vpe->col_idx
+ * during the update, hence the lock below which must also be
+ * taken on any vLPI handling path that evaluates vpe->col_idx.
*/
- if (vpe->col_idx == cpu)
+ from = vpe_to_cpuid_lock(vpe, &flags);
+ if (from == cpu)
goto out;
- from = vpe->col_idx;
vpe->col_idx = cpu;
/*
@@ -3512,6 +3550,7 @@ static int its_vpe_set_affinity(struct irq_data *d,
out:
irq_data_update_effective_affinity(d, cpumask_of(cpu));
+ vpe_to_cpuid_unlock(vpe, flags);
return IRQ_SET_MASK_OK_DONE;
}
@@ -3855,6 +3894,7 @@ static int its_vpe_init(struct its_vpe *vpe)
return -ENOMEM;
}
+ raw_spin_lock_init(&vpe->vpe_lock);
vpe->vpe_id = vpe_id;
vpe->vpt_page = vpt_page;
if (gic_rdists->has_rvpeid)
diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h
index d9c34968467a..439963f4c66a 100644
--- a/include/linux/irqchip/arm-gic-v4.h
+++ b/include/linux/irqchip/arm-gic-v4.h
@@ -54,6 +54,11 @@ struct its_vpe {
};
/*
+ * Ensures mutual exclusion between affinity setting of the
+ * vPE and vLPI operations using vpe->col_idx.
+ */
+ raw_spinlock_t vpe_lock;
+ /*
* This collection ID is used to indirect the target
* redistributor for this VPE. The ID itself isn't involved in
* programming of the ITS.