arm/mach-vexpress: array accessed out of bounds

dcscb_allcpus_mask is an array of size 2.

The index variable cluster has to be checked against this limit
before accessing the array.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/arm/mach-vexpress/dcscb.c b/arch/arm/mach-vexpress/dcscb.c
index 788495d35cf9..30b993399ed7 100644
--- a/arch/arm/mach-vexpress/dcscb.c
+++ b/arch/arm/mach-vexpress/dcscb.c
@@ -51,12 +51,14 @@ static int dcscb_allcpus_mask[2];
 static int dcscb_power_up(unsigned int cpu, unsigned int cluster)
 {
         unsigned int rst_hold, cpumask = (1 << cpu);
-        unsigned int all_mask = dcscb_allcpus_mask[cluster];
+        unsigned int all_mask;
 
         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
         if (cpu >= 4 || cluster >= 2)
                 return -EINVAL;
 
+        all_mask = dcscb_allcpus_mask[cluster];
+
         /*
          * Since this is called with IRQs enabled, and no arch_spin_lock_irq
          * variant exists, we need to disable IRQs manually here.
@@ -101,11 +103,12 @@ static void dcscb_power_down(void)
         cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
         cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
         cpumask = (1 << cpu);
-        all_mask = dcscb_allcpus_mask[cluster];
 
         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
         BUG_ON(cpu >= 4 || cluster >= 2);
 
+        all_mask = dcscb_allcpus_mask[cluster];
+
         __mcpm_cpu_going_down(cpu, cluster);
 
         arch_spin_lock(&dcscb_lock);