hw/intc/arm_gicv3: fix an extra left-shift when reading IPRIORITYR

When either GICD_IPRIORITYR or GICR_IPRIORITYR is read as a 32-bit
register, the post left-shift operator in the for loop causes an
extra shift after the least significant byte has been placed.

The 32-bit value actually returned is therefore the expected value
shifted left by 8 bits.

Signed-off-by: Amol Surati <suratiamol@gmail.com>
Message-id: 20180614054857.26248-1-suratiamol@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/intc/arm_gicv3_dist.c

@@ -441,7 +441,8 @@ static MemTxResult gicd_readl(GICv3State *s, hwaddr offset,
         int i, irq = offset - GICD_IPRIORITYR;
         uint32_t value = 0;
 
-        for (i = irq + 3; i >= irq; i--, value <<= 8) {
+        for (i = irq + 3; i >= irq; i--) {
+            value <<= 8;
             value |= gicd_read_ipriorityr(s, attrs, i);
         }
         *data = value;

hw/intc/arm_gicv3_redist.c

@@ -192,7 +192,8 @@ static MemTxResult gicr_readl(GICv3CPUState *cs, hwaddr offset,
         int i, irq = offset - GICR_IPRIORITYR;
         uint32_t value = 0;
 
-        for (i = irq + 3; i >= irq; i--, value <<= 8) {
+        for (i = irq + 3; i >= irq; i--) {
+            value <<= 8;
             value |= gicr_read_ipriorityr(cs, attrs, i);
         }
         *data = value;