From e3c0869f6fbd8008b556738384e3f3a22cf981c3 Mon Sep 17 00:00:00 2001
From: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Date: Mon, 24 Jun 2024 14:35:46 +0100
Subject: [PATCH] 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 |  6 ++-
 lib/xlat_tables_v2/xlat_tables_utils.c     | 56 ++++++++++++++++++++--
 2 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/include/lib/xlat_tables/xlat_tables_defs.h b/include/lib/xlat_tables/xlat_tables_defs.h
index 2d0949b51..5434a9a27 100644
--- a/include/lib/xlat_tables/xlat_tables_defs.h
+++ b/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. */
diff --git a/lib/xlat_tables_v2/xlat_tables_utils.c b/lib/xlat_tables_v2/xlat_tables_utils.c
index f3a53ccd3..a3b913c26 100644
--- a/lib/xlat_tables_v2/xlat_tables_utils.c
+++ b/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);