4.9-stable review patch. If anyone has any objections, please let me know.
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From: Shanker Donthineni shankerd@codeaurora.org
commit 21ec30c0ef5234fb1039cc7c7737d885bf875a9e upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/irqchip/irq-gic-v3.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -616,7 +616,7 @@ static void gic_raise_softirq(const stru * Ensure that stores to Normal memory are visible to the * other CPUs before issuing the IPI. */ - smp_wmb(); + wmb();
for_each_cpu(cpu, mask) { unsigned long cluster_id = cpu_logical_map(cpu) & ~0xffUL;