Fix CPU_SUSPEND when invoked with affinity level higher than get_max_afflvl()

This patch fixes the assertion failure when CPU_SUSPEND is invoked with
an affinity level higher than supported by the platform by adding suitable
checks for affinity level within `psci_cpu_suspend`. Also added suitable
bound checks within `psci_aff_map_get_idx` to prevent indexing beyond array
limits.

Fixes ARM-software/tf-issues#260

Change-Id: I04b75c49729e6c6d1983add590f60146c8fc3630

services/std_svc/psci/psci_common.c

@@ -201,7 +201,7 @@ unsigned long mpidr_set_aff_inst(unsigned long mpidr,
 int psci_check_afflvl_range(int start_afflvl, int end_afflvl)
 {
 	/* Sanity check the parameters passed */
-	if (end_afflvl > MPIDR_MAX_AFFLVL)
+	if (end_afflvl > get_max_afflvl())
 		return PSCI_E_INVALID_PARAMS;
 
 	if (start_afflvl < MPIDR_AFFLVL0)

services/std_svc/psci/psci_main.c

@@ -86,7 +86,7 @@ int psci_cpu_suspend(unsigned int power_state,
 
 	/* Sanity check the requested state */
 	target_afflvl = psci_get_pstate_afflvl(power_state);
-	if (target_afflvl > MPIDR_MAX_AFFLVL)
+	if (target_afflvl > get_max_afflvl())
 		return PSCI_E_INVALID_PARAMS;
 
 	/* Determine the 'state type' in the 'power_state' parameter */

services/std_svc/psci/psci_setup.c

@@ -76,6 +76,11 @@ static int psci_aff_map_get_idx(unsigned long key,
 	if (max_idx < min_idx)
 		return PSCI_E_INVALID_PARAMS;
 
+	/*
+	 * Make sure we are within array limits.
+	 */
+	assert(min_idx >= 0 && max_idx < PSCI_NUM_AFFS);
+
 	/*
 	 * Bisect the array around 'mid' and then recurse into the array chunk
 	 * where the key is likely to be found. The mpidrs in each node in the
@@ -83,6 +88,7 @@ static int psci_aff_map_get_idx(unsigned long key,
 	 * order which makes the binary search possible.
 	 */
 	mid = min_idx + ((max_idx - min_idx) >> 1);	/* Divide by 2 */
+
 	if (psci_aff_map[mid].mpidr > key)
 		return psci_aff_map_get_idx(key, min_idx, mid - 1);
 	else if (psci_aff_map[mid].mpidr < key)
@@ -95,6 +101,9 @@ aff_map_node_t *psci_get_aff_map_node(unsigned long mpidr, int aff_lvl)
 {
 	int rc;
 
+	if (aff_lvl > get_max_afflvl())
+		return NULL;
+
 	/* Right shift the mpidr to the required affinity level */
 	mpidr = mpidr_mask_lower_afflvls(mpidr, aff_lvl);