diff mbox series

[kvm-unit-tests,v4,04/11] arm/arm64: gic: Remove unnecessary synchronization with stats_reset()

Message ID 20210219121337.76533-5-alexandru.elisei@arm.com (mailing list archive)
State New, archived
Headers show
Series GIC fixes and improvements | expand

Commit Message

Alexandru Elisei Feb. 19, 2021, 12:13 p.m. UTC 
The GICv3 driver executes a DSB barrier before sending an IPI, which
ensures that memory accesses have completed. This removes the need to
enforce ordering with respect to stats_reset() in the IPI handler.

For GICv2, the wmb() from writel(), executed when triggering an IPI,
coupled with the rmb() from readl() when handling the IPI will enforce the
desired memory ordering.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
 arm/gic.c | 2 --
 1 file changed, 2 deletions(-)
diff mbox series

Patch

diff --git a/arm/gic.c b/arm/gic.c
index 8bb804abf34d..db1417ae1ca1 100644
--- a/arm/gic.c
+++ b/arm/gic.c
@@ -59,7 +59,6 @@  static void stats_reset(void)
 		bad_sender[i] = -1;
 		bad_irq[i] = -1;
 	}
-	smp_wmb();
 }
 
 static void check_acked(const char *testname, cpumask_t *mask)
@@ -149,7 +148,6 @@  static void ipi_handler(struct pt_regs *regs __unused)
 
 	if (irqnr != GICC_INT_SPURIOUS) {
 		gic_write_eoir(irqstat);
-		smp_rmb(); /* pairs with wmb in stats_reset */
 		++acked[smp_processor_id()];
 		check_ipi_sender(irqstat);
 		check_irqnr(irqnr);