MIPS: GIC: Prevent array overrun

commit ffc8415a upstream.

A GIC interrupt which is declared as having a GIC_MAP_TO_NMI_MSK
mapping causes the cpu parameter to gic_setup_intr() to be increased
to 32, causing memory corruption when pcpu_masks[] is written to again
later in the function.
Signed-off-by: Jeffrey Deans <jeffrey.deans@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7375/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

arch/mips/kernel/irq-gic.c

@@ -166,11 +166,13 @@ static void __init gic_setup_intr(unsigned int intr, unsigned int cpu,
 {
 	/* Setup Intr to Pin mapping */
 	if (pin & GIC_MAP_TO_NMI_MSK) {
+		int i;
+
 		GICWRITE(GIC_REG_ADDR(SHARED, GIC_SH_MAP_TO_PIN(intr)), pin);
 		/* FIXME: hack to route NMI to all cpu's */
-		for (cpu = 0; cpu < NR_CPUS; cpu += 32) {
+		for (i = 0; i < NR_CPUS; i += 32) {
 			GICWRITE(GIC_REG_ADDR(SHARED,
-					  GIC_SH_MAP_TO_VPE_REG_OFF(intr, cpu)),
+					  GIC_SH_MAP_TO_VPE_REG_OFF(intr, i)),
 				 0xffffffff);
 		}
 	} else {