core: sp: fix FFA_MEM_RECLAIM checks

Currently it is assumed that a NS endpoint's ID is always 0. This is not
true if multiple VMs are present in the NWd, so the check will fail when
reclaiming shared memory from an SP. Fix this by removing the owner ID
check if the reclaim call comes from NWd, in this case the necessary
checks are done by the hypervisor.

Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Balint Dobszay <balint.dobszay@arm.com>

core/arch/arm/kernel/spmc_sp_handler.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: BSD-2-Clause
 /*
- * Copyright (c) 2021-2022, Arm Limited
+ * Copyright (c) 2021-2023, Arm Limited
  */
 #include <assert.h>
 #include <bench.h>
@@ -768,7 +768,6 @@ bool ffa_mem_reclaim(struct thread_smc_args *args,
 {
 	uint64_t handle = reg_pair_to_64(args->a2, args->a1);
 	uint32_t flags = args->a3;
-	uint32_t endpoint = 0;
 	struct sp_mem *smem = NULL;
 	struct sp_mem_receiver *receiver  = NULL;
 	uint32_t exceptions = 0;
@@ -777,12 +776,12 @@ bool ffa_mem_reclaim(struct thread_smc_args *args,
 	if (!smem)
 		return false;
 
-	if (caller_sp)
-		endpoint = caller_sp->endpoint_id;
-
-	/* Make sure that the caller is the owner of the share */
-	if (smem->sender_id != endpoint) {
-		ffa_set_error(args, FFA_DENIED);
+	/*
+	 * If the caller is an SP, make sure that it is the owner of the share.
+	 * If the call comes from NWd this is ensured by the hypervisor.
+	 */
+	if (caller_sp && caller_sp->endpoint_id != smem->sender_id) {
+		ffa_set_error(args, FFA_INVALID_PARAMETERS);
 		return true;
 	}