1 files changed, 45 insertions, 1 deletions
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 3cbc4058dd2..493f3fd9f13 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -12,7 +12,16 @@
  * Very basic string functions
  */
 
-#include "boot.h"
+#include <linux/types.h>
+#include "ctype.h"
+
+int memcmp(const void *s1, const void *s2, size_t len)
+{
+	u8 diff;
+	asm("repe; cmpsb; setnz %0"
+	    : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
+	return diff;
+}
 
 int strcmp(const char *str1, const char *str2)
 {
@@ -111,3 +120,38 @@ unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int bas
 
 	return result;
 }
+
+/**
+ * strlen - Find the length of a string
+ * @s: The string to be sized
+ */
+size_t strlen(const char *s)
+{
+	const char *sc;
+
+	for (sc = s; *sc != '\0'; ++sc)
+		/* nothing */;
+	return sc - s;
+}
+
+/**
+ * strstr - Find the first substring in a %NUL terminated string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ */
+char *strstr(const char *s1, const char *s2)
+{
+	size_t l1, l2;
+
+	l2 = strlen(s2);
+	if (!l2)
+		return (char *)s1;
+	l1 = strlen(s1);
+	while (l1 >= l2) {
+		l1--;
+		if (!memcmp(s1, s2, l2))
+			return (char *)s1;
+		s1++;
+	}
+	return NULL;
+}