1 files changed, 348 insertions, 0 deletions
diff --git a/arch/s390/lib/string.c b/arch/s390/lib/string.c
new file mode 100644
index 0000000000..7d87418182
--- /dev/null
+++ b/arch/s390/lib/string.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Optimized string functions
+ *
+ *  S390 version
+ *    Copyright IBM Corp. 2004
+ *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
+ */
+
+#define IN_ARCH_STRING_C 1
+#ifndef __NO_FORTIFY
+# define __NO_FORTIFY
+#endif
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/export.h>
+
+/*
+ * Helper functions to find the end of a string
+ */
+static inline char *__strend(const char *s)
+{
+	unsigned long e = 0;
+
+	asm volatile(
+		"	lghi	0,0\n"
+		"0:	srst	%[e],%[s]\n"
+		"	jo	0b\n"
+		: [e] "+&a" (e), [s] "+&a" (s)
+		:
+		: "cc", "memory", "0");
+	return (char *)e;
+}
+
+static inline char *__strnend(const char *s, size_t n)
+{
+	const char *p = s + n;
+
+	asm volatile(
+		"	lghi	0,0\n"
+		"0:	srst	%[p],%[s]\n"
+		"	jo	0b\n"
+		: [p] "+&d" (p), [s] "+&a" (s)
+		:
+		: "cc", "memory", "0");
+	return (char *)p;
+}
+
+/**
+ * strlen - Find the length of a string
+ * @s: The string to be sized
+ *
+ * returns the length of @s
+ */
+#ifdef __HAVE_ARCH_STRLEN
+size_t strlen(const char *s)
+{
+	return __strend(s) - s;
+}
+EXPORT_SYMBOL(strlen);
+#endif
+
+/**
+ * strnlen - Find the length of a length-limited string
+ * @s: The string to be sized
+ * @n: The maximum number of bytes to search
+ *
+ * returns the minimum of the length of @s and @n
+ */
+#ifdef __HAVE_ARCH_STRNLEN
+size_t strnlen(const char *s, size_t n)
+{
+	return __strnend(s, n) - s;
+}
+EXPORT_SYMBOL(strnlen);
+#endif
+
+/**
+ * strcpy - Copy a %NUL terminated string
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ *
+ * returns a pointer to @dest
+ */
+#ifdef __HAVE_ARCH_STRCPY
+char *strcpy(char *dest, const char *src)
+{
+	char *ret = dest;
+
+	asm volatile(
+		"	lghi	0,0\n"
+		"0:	mvst	%[dest],%[src]\n"
+		"	jo	0b\n"
+		: [dest] "+&a" (dest), [src] "+&a" (src)
+		:
+		: "cc", "memory", "0");
+	return ret;
+}
+EXPORT_SYMBOL(strcpy);
+#endif
+
+/**
+ * strncpy - Copy a length-limited, %NUL-terminated string
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @n: The maximum number of bytes to copy
+ *
+ * The result is not %NUL-terminated if the source exceeds
+ * @n bytes.
+ */
+#ifdef __HAVE_ARCH_STRNCPY
+char *strncpy(char *dest, const char *src, size_t n)
+{
+	size_t len = __strnend(src, n) - src;
+	memset(dest + len, 0, n - len);
+	memcpy(dest, src, len);
+	return dest;
+}
+EXPORT_SYMBOL(strncpy);
+#endif
+
+/**
+ * strcat - Append one %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ *
+ * returns a pointer to @dest
+ */
+#ifdef __HAVE_ARCH_STRCAT
+char *strcat(char *dest, const char *src)
+{
+	unsigned long dummy = 0;
+	char *ret = dest;
+
+	asm volatile(
+		"	lghi	0,0\n"
+		"0:	srst	%[dummy],%[dest]\n"
+		"	jo	0b\n"
+		"1:	mvst	%[dummy],%[src]\n"
+		"	jo	1b\n"
+		: [dummy] "+&a" (dummy), [dest] "+&a" (dest), [src] "+&a" (src)
+		:
+		: "cc", "memory", "0");
+	return ret;
+}
+EXPORT_SYMBOL(strcat);
+#endif
+
+/**
+ * strlcat - Append a length-limited, %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ * @n: The size of the destination buffer.
+ */
+#ifdef __HAVE_ARCH_STRLCAT
+size_t strlcat(char *dest, const char *src, size_t n)
+{
+	size_t dsize = __strend(dest) - dest;
+	size_t len = __strend(src) - src;
+	size_t res = dsize + len;
+
+	if (dsize < n) {
+		dest += dsize;
+		n -= dsize;
+		if (len >= n)
+			len = n - 1;
+		dest[len] = '\0';
+		memcpy(dest, src, len);
+	}
+	return res;
+}
+EXPORT_SYMBOL(strlcat);
+#endif
+
+/**
+ * strncat - Append a length-limited, %NUL-terminated string to another
+ * @dest: The string to be appended to
+ * @src: The string to append to it
+ * @n: The maximum numbers of bytes to copy
+ *
+ * returns a pointer to @dest
+ *
+ * Note that in contrast to strncpy, strncat ensures the result is
+ * terminated.
+ */
+#ifdef __HAVE_ARCH_STRNCAT
+char *strncat(char *dest, const char *src, size_t n)
+{
+	size_t len = __strnend(src, n) - src;
+	char *p = __strend(dest);
+
+	p[len] = '\0';
+	memcpy(p, src, len);
+	return dest;
+}
+EXPORT_SYMBOL(strncat);
+#endif
+
+/**
+ * strcmp - Compare two strings
+ * @s1: One string
+ * @s2: Another string
+ *
+ * returns   0 if @s1 and @s2 are equal,
+ *	   < 0 if @s1 is less than @s2
+ *	   > 0 if @s1 is greater than @s2
+ */
+#ifdef __HAVE_ARCH_STRCMP
+int strcmp(const char *s1, const char *s2)
+{
+	int ret = 0;
+
+	asm volatile(
+		"	lghi	0,0\n"
+		"0:	clst	%[s1],%[s2]\n"
+		"	jo	0b\n"
+		"	je	1f\n"
+		"	ic	%[ret],0(%[s1])\n"
+		"	ic	0,0(%[s2])\n"
+		"	sr	%[ret],0\n"
+		"1:"
+		: [ret] "+&d" (ret), [s1] "+&a" (s1), [s2] "+&a" (s2)
+		:
+		: "cc", "memory", "0");
+	return ret;
+}
+EXPORT_SYMBOL(strcmp);
+#endif
+
+static inline int clcle(const char *s1, unsigned long l1,
+			const char *s2, unsigned long l2)
+{
+	union register_pair r1 = { .even = (unsigned long)s1, .odd = l1, };
+	union register_pair r3 = { .even = (unsigned long)s2, .odd = l2, };
+	int cc;
+
+	asm volatile(
+		"0:	clcle	%[r1],%[r3],0\n"
+		"	jo	0b\n"
+		"	ipm	%[cc]\n"
+		"	srl	%[cc],28\n"
+		: [cc] "=&d" (cc), [r1] "+&d" (r1.pair), [r3] "+&d" (r3.pair)
+		:
+		: "cc", "memory");
+	return cc;
+}
+
+/**
+ * strstr - Find the first substring in a %NUL terminated string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ */
+#ifdef __HAVE_ARCH_STRSTR
+char *strstr(const char *s1, const char *s2)
+{
+	int l1, l2;
+
+	l2 = __strend(s2) - s2;
+	if (!l2)
+		return (char *) s1;
+	l1 = __strend(s1) - s1;
+	while (l1-- >= l2) {
+		int cc;
+
+		cc = clcle(s1, l2, s2, l2);
+		if (!cc)
+			return (char *) s1;
+		s1++;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(strstr);
+#endif
+
+/**
+ * memchr - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first occurrence of @c, or %NULL
+ * if @c is not found
+ */
+#ifdef __HAVE_ARCH_MEMCHR
+void *memchr(const void *s, int c, size_t n)
+{
+	const void *ret = s + n;
+
+	asm volatile(
+		"	lgr	0,%[c]\n"
+		"0:	srst	%[ret],%[s]\n"
+		"	jo	0b\n"
+		"	jl	1f\n"
+		"	la	%[ret],0\n"
+		"1:"
+		: [ret] "+&a" (ret), [s] "+&a" (s)
+		: [c] "d" (c)
+		: "cc", "memory", "0");
+	return (void *) ret;
+}
+EXPORT_SYMBOL(memchr);
+#endif
+
+/**
+ * memcmp - Compare two areas of memory
+ * @s1: One area of memory
+ * @s2: Another area of memory
+ * @n: The size of the area.
+ */
+#ifdef __HAVE_ARCH_MEMCMP
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+	int ret;
+
+	ret = clcle(s1, n, s2, n);
+	if (ret)
+		ret = ret == 1 ? -1 : 1;
+	return ret;
+}
+EXPORT_SYMBOL(memcmp);
+#endif
+
+/**
+ * memscan - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first occurrence of @c, or 1 byte past
+ * the area if @c is not found
+ */
+#ifdef __HAVE_ARCH_MEMSCAN
+void *memscan(void *s, int c, size_t n)
+{
+	const void *ret = s + n;
+
+	asm volatile(
+		"	lgr	0,%[c]\n"
+		"0:	srst	%[ret],%[s]\n"
+		"	jo	0b\n"
+		: [ret] "+&a" (ret), [s] "+&a" (s)
+		: [c] "d" (c)
+		: "cc", "memory", "0");
+	return (void *)ret;
+}
+EXPORT_SYMBOL(memscan);
+#endif