irqchip/gic-v3: Use wmb() instead of smb_wmb() in gic_raise_softirq()

A DMB instruction can be used to ensure the relative order of only
memory accesses before and after the barrier. Since writes to system
registers are not memory operations, barrier DMB is not sufficient
for observability of memory accesses that occur before ICC_SGI1R_EL1
writes.

A DSB instruction ensures that no instructions that appear in program
order after the DSB instruction, can execute until the DSB instruction
has completed.

Cc: stable@vger.kernel.org
Acked-by: Will Deacon <will.deacon@arm.com>,
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index d71be9a1f9d286db047083c931a54816533ab12c..d99cc07903ec497279e3baf563743d9146e77f09 100644 (file)
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -688,7 +688,7 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
         * Ensure that stores to Normal memory are visible to the
         * other CPUs before issuing the IPI.
         */
-       smp_wmb();
+       wmb();
 
        for_each_cpu(cpu, mask) {
                u64 cluster_id = MPIDR_TO_SGI_CLUSTER_ID(cpu_logical_map(cpu));