spd: trusty: allow clients to retrieve service UUID

This patch implements support for the 64-bit and 32-bit versions of
0xBF00FF01 SMC function ID, as documented by the SMCCC, to allow
non-secure world clients to query SPD's UUID.

In order to service this FID, the Trusty SPD now increases the range
of SMCs that it services. To restrict Trusty from receiving the extra
SMC FIDs, this patch drops any unsupported FID.

Verified with TFTF tests for UID query and internal gtest for Trusty.

Change-Id: If96fe4993f7e641595cfe67cc6b4210a0d52403f
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

services/spd/trusty/smcall.h

 /*
  * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -71,4 +72,11 @@
 #define SMC_YC_VDEV_KICK_VQ	  SMC_YIELDCALL_NR(SMC_ENTITY_TRUSTED_OS, 24U)
 #define SMC_YC_SET_ROT_PARAMS	  SMC_YIELDCALL_NR(SMC_ENTITY_TRUSTED_OS, 65535U)
 
+/*
+ * Standard Trusted OS Function IDs that fall under Trusted OS call range
+ * according to SMC calling convention
+ */
+#define SMC_FC64_GET_UUID		SMC_FASTCALL64_NR(63U, 0xFF01U) /* Implementation UID */
+#define SMC_FC_GET_UUID			SMC_FASTCALL_NR(63U, 0xFF01U) /* Implementation.UID */
+
 #endif /* SMCALL_H */

services/spd/trusty/trusty.c

 /*
  * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -16,11 +17,18 @@
 #include <common/debug.h>
 #include <common/runtime_svc.h>
 #include <lib/el3_runtime/context_mgmt.h>
+#include <lib/smccc.h>
 #include <plat/common/platform.h>
+#include <tools_share/uuid.h>
 
 #include "sm_err.h"
 #include "smcall.h"
 
+/* Trusty UID: RFC-4122 compliant UUID version 4 */
+DEFINE_SVC_UUID2(trusty_uuid,
+		 0x40ee25f0, 0xa2bc, 0x304c, 0x8c, 0x4c,
+		 0xa1, 0x73, 0xc5, 0x7d, 0x8a, 0xf1);
+
 /* macro to check if Hypervisor is enabled in the HCR_EL2 register */
 #define HYP_ENABLE_FLAG		0x286001U
 
@@ -256,6 +264,11 @@ static uintptr_t trusty_smc_handler(uint32_t smc_fid,
 		SMC_RET1(handle, SMC_UNK);
 	} else {
 		switch (smc_fid) {
+		case SMC_FC64_GET_UUID:
+		case SMC_FC_GET_UUID:
+			/* provide the UUID for the service to the client */
+			SMC_UUID_RET(handle, trusty_uuid);
+			break;
 		case SMC_FC64_SET_FIQ_HANDLER:
 			return trusty_set_fiq_handler(handle, x1, x2, x3);
 		case SMC_FC64_GET_FIQ_REGS:
@@ -263,6 +276,12 @@ static uintptr_t trusty_smc_handler(uint32_t smc_fid,
 		case SMC_FC_FIQ_EXIT:
 			return trusty_fiq_exit(handle, x1, x2, x3);
 		default:
+			/* Not all OENs greater than SMC_ENTITY_SECURE_MONITOR are supported */
+			if (SMC_ENTITY(smc_fid) > SMC_ENTITY_SECURE_MONITOR) {
+				VERBOSE("%s: unsupported SMC FID (0x%x)\n", __func__, smc_fid);
+				SMC_RET1(handle, SMC_UNK);
+			}
+
 			if (is_hypervisor_mode())
 				vmid = SMC_GET_GP(handle, CTX_GPREG_X7);
 
@@ -502,7 +521,7 @@ DECLARE_RT_SVC(
 	trusty_fast,
 
 	OEN_TOS_START,
-	SMC_ENTITY_SECURE_MONITOR,
+	OEN_TOS_END,
 	SMC_TYPE_FAST,
 	trusty_setup,
 	trusty_smc_handler