[PATCH 4.4 47/60] irqchip/gic-v3: Add missing barrier to 32bit version of gic_read_iar()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@xxxxxxx>

commit 8f318526a292c5e7cebb82f3f766b83c22343293 upstream.

Commit 1a1ebd5 ("irqchip/gic-v3: Make sure read from ICC_IAR1_EL1 is
visible on redestributor") fixed the missing barrier on arm64, but
forgot to update the 32bit counterpart, which has the same requirements.
Let's fix it.

Fixes: 1a1ebd5 ("irqchip/gic-v3: Make sure read from ICC_IAR1_EL1 is visible on redestributor")
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm/include/asm/arch_gicv3.h |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/arm/include/asm/arch_gicv3.h
+++ b/arch/arm/include/asm/arch_gicv3.h
@@ -117,6 +117,7 @@ static inline u32 gic_read_iar(void)
 	u32 irqstat;
 
 	asm volatile("mrc " __stringify(ICC_IAR1) : "=r" (irqstat));
+	dsb(sy);
 	return irqstat;
 }