diff --git a/lib/libc/memchr.c b/lib/libc/memchr.c
index 66d7ba1..e009a5f 100644
--- a/lib/libc/memchr.c
+++ b/lib/libc/memchr.c
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2013-2019, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <stddef.h>
-#include <string.h>
+#include <string_private.h>
 
 void *memchr(const void *src, int c, size_t len)
 {
diff --git a/lib/libc/memcmp.c b/lib/libc/memcmp.c
index db2701b..1458208 100644
--- a/lib/libc/memcmp.c
+++ b/lib/libc/memcmp.c
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2013-2019, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <stddef.h>
-#include <string.h>
+#include <string_private.h>
 
 int memcmp(const void *s1, const void *s2, size_t len)
 {
diff --git a/lib/libc/memcpy.c b/lib/libc/memcpy.c
index af9ed45..ca31de5 100644
--- a/lib/libc/memcpy.c
+++ b/lib/libc/memcpy.c
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2013-2019, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <stddef.h>
-#include <string.h>
+#include <string_private.h>
 
 void *memcpy(void *dst, const void *src, size_t len)
 {
diff --git a/lib/libc/memcpy_s.c b/lib/libc/memcpy_s.c
index 26953bf..ee87637 100644
--- a/lib/libc/memcpy_s.c
+++ b/lib/libc/memcpy_s.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
  * Copyright (c) 2023, Intel Corporation. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
@@ -53,12 +53,7 @@
 		}
 	}
 
-	/*
-	 * Start copy process when there is no error
-	 */
-	while (ssize--) {
-		d[ssize] = s[ssize];
-	}
+	(void)memcpy(dst, src, ssize);
 
 	return 0;
 }
diff --git a/lib/libc/memset.c b/lib/libc/memset.c
index c5bac8d..2513221 100644
--- a/lib/libc/memset.c
+++ b/lib/libc/memset.c
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2013-2020, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <stddef.h>
-#include <string.h>
+#include <string_private.h>
 #include <stdint.h>
 
 void *memset(void *dst, int val, size_t count)
diff --git a/lib/libc/strchr.c b/lib/libc/strchr.c
index 1cd03ca..b3bebe4 100644
--- a/lib/libc/strchr.c
+++ b/lib/libc/strchr.c
@@ -30,12 +30,12 @@
  */
 
 /*
- * Portions copyright (c) 2018, Arm Limited and Contributors.
+ * Portions copyright (c) 2018-2025, Arm Limited and Contributors.
  * All rights reserved.
  */
 
 #include <stddef.h>
-#include <string.h>
+#include <string_private.h>
 
 char *
 strchr(const char *p, int ch)
diff --git a/lib/libc/strcmp.c b/lib/libc/strcmp.c
index 290db4c..5afd0e9 100644
--- a/lib/libc/strcmp.c
+++ b/lib/libc/strcmp.c
@@ -33,11 +33,11 @@
  */
 
 /*
- * Portions copyright (c) 2018, Arm Limited and Contributors.
+ * Portions copyright (c) 2018-2025, Arm Limited and Contributors.
  * All rights reserved.
  */
 
-#include <string.h>
+#include <string_private.h>
 
 /*
  * Compare strings.
diff --git a/lib/libc/strlen.c b/lib/libc/strlen.c
index e4b79d9..cc1d1df 100644
--- a/lib/libc/strlen.c
+++ b/lib/libc/strlen.c
@@ -1,10 +1,10 @@
 /*
- * Copyright (c) 2018, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2025, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#include <string.h>
+#include <string_private.h>
 
 size_t strlen(const char *s)
 {
diff --git a/lib/libc/strncmp.c b/lib/libc/strncmp.c
index f0bbadc..828e0c5 100644
--- a/lib/libc/strncmp.c
+++ b/lib/libc/strncmp.c
@@ -30,11 +30,11 @@
  */
 
 /*
- * Portions copyright (c) 2018, Arm Limited and Contributors.
+ * Portions copyright (c) 2018-2025, Arm Limited and Contributors.
  * All rights reserved.
  */
 
-#include <string.h>
+#include <string_private.h>
 
 int
 strncmp(const char *s1, const char *s2, size_t n)
diff --git a/lib/libc/strrchr.c b/lib/libc/strrchr.c
index cd435ff..98f76c6 100644
--- a/lib/libc/strrchr.c
+++ b/lib/libc/strrchr.c
@@ -30,7 +30,7 @@
  */
 
 #include <stddef.h>
-#include <string.h>
+#include <string_private.h>
 
 char *
 strrchr(const char *p, int ch)