fix(xlat): correct attribute retrieval in a RME enabled system

In a system enabled with RME, the function
'xlat_get_mem_attributes_internal' fails to accurately provide
'output PA space' for Realm and Root memory because it does not
consider the 'nse' bit in page table descriptor.
This patch resolves the issue by extracting the 'nse' bit value.
As a result, it ensures correct retrieval of attributes
in RME-enabled systems while maintaining unaffected attribute
retrieval for non-RME systems.

Change-Id: If2d01545b921c9074f48c52a98027ff331e14237
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>

include/lib/xlat_tables/xlat_tables_defs.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -171,8 +171,10 @@
 #define SHAREABILITY_SHIFT		8
 /* The Access Flag, AF. */
 #define ACCESS_FLAG_SHIFT		10
-/* The not global bit, nG. */
+/* The not global bit, nG */
 #define NOT_GLOBAL_SHIFT		11
+/* The Non-secure Extension bit, NSE */
+#define NSE_SHIFT			11
 /* Contiguous hint bit. */
 #define CONT_HINT_SHIFT			52
 /* Execute-never bits, XN. */

lib/xlat_tables_v2/xlat_tables_utils.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -13,6 +13,7 @@
 
 #include <platform_def.h>
 
+#include <arch_features.h>
 #include <arch_helpers.h>
 #include <common/debug.h>
 #include <lib/utils_def.h>
@@ -419,10 +420,59 @@ static int xlat_get_mem_attributes_internal(const xlat_ctx_t *ctx,
 			*attributes |= MT_USER;
 	}
 
-	uint64_t ns_bit = (desc >> NS_SHIFT) & 1U;
+	uint64_t ns_bit = (desc >> NS_SHIFT) & 1ULL;
 
-	if (ns_bit == 1U)
+#if ENABLE_RME
+	uint64_t nse_bit = (desc >> NSE_SHIFT) & 1ULL;
+	uint32_t sec_state = (uint32_t)(ns_bit | (nse_bit << 1ULL));
+
+/*
+ * =========================================================
+ *  NSE    NS  |  Output PA space
+ * =========================================================
+ *    0    0   |  Secure (if S-EL2 is present, else invalid)
+ *    0    1   |  Non-secure
+ *    1    0   |  Root
+ *    1    1   |  Realm
+ *==========================================================
+ */
+	switch (sec_state) {
+	case 0U:
+		/*
+		 * We expect to get Secure mapping on an RME system only if
+		 * S-EL2 is enabled.
+		 * Hence panic() if we hit the case without EEL2 being enabled.
+		 */
+		if ((read_scr_el3() & SCR_EEL2_BIT) == 0ULL) {
+			ERROR("A secure descriptor is not supported when"
+			      "FEAT_RME is implemented and FEAT_SEL2 is"
+			      "not enabled\n");
+			panic();
+		} else {
+			*attributes |= MT_SECURE;
+		}
+		break;
+	case 1U:
 		*attributes |= MT_NS;
+		break;
+	case 2U:
+		*attributes |= MT_ROOT;
+		break;
+	case 3U:
+		*attributes |= MT_REALM;
+		break;
+	default:
+		/* unreachable code */
+		assert(false);
+		break;
+	}
+#else /* !ENABLE_RME */
+	if (ns_bit == 1ULL) {
+		*attributes |= MT_NS;
+	} else {
+		*attributes |= MT_SECURE;
+	}
+#endif /* ENABLE_RME */
 
 	uint64_t xn_mask = xlat_arch_regime_get_xn_desc(ctx->xlat_regime);