diff --git a/lib/pmf/pmf_main.c b/lib/pmf/pmf_main.c
index bf0ad83..b33f49c 100644
--- a/lib/pmf/pmf_main.c
+++ b/lib/pmf/pmf_main.c
@@ -165,7 +165,7 @@
 	/* Search for registered service. */
 	svc_desc = get_service(tid);
 
-	if ((svc_desc == NULL) || (plat_core_pos_by_mpidr(mpidr) < 0)) {
+	if (svc_desc == NULL) {
 		*ts_value = 0;
 		return -EINVAL;
 	} else {
diff --git a/lib/pmf/pmf_smc.c b/lib/pmf/pmf_smc.c
index 71486df..f3dd112 100644
--- a/lib/pmf/pmf_smc.c
+++ b/lib/pmf/pmf_smc.c
@@ -26,6 +26,10 @@
 	int rc;
 	unsigned long long ts_value;
 
+	/* Determine if the cpu exists of not */
+	if (!is_valid_mpidr(x2))
+		return PSCI_E_INVALID_PARAMS;
+
 	if (((smc_fid >> FUNCID_CC_SHIFT) & FUNCID_CC_MASK) == SMC_32) {
 
 		x1 = (uint32_t)x1;