| // 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 |
| |
| #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) |
| { |
| register unsigned long r0 asm("0") = 0; |
| |
| asm volatile ("0: srst %0,%1\n" |
| " jo 0b" |
| : "+d" (r0), "+a" (s) : : "cc", "memory"); |
| return (char *) r0; |
| } |
| |
| static inline char *__strnend(const char *s, size_t n) |
| { |
| register unsigned long r0 asm("0") = 0; |
| const char *p = s + n; |
| |
| asm volatile ("0: srst %0,%1\n" |
| " jo 0b" |
| : "+d" (p), "+a" (s) : "d" (r0) : "cc", "memory"); |
| 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) |
| { |
| register int r0 asm("0") = 0; |
| char *ret = dest; |
| |
| asm volatile ("0: mvst %0,%1\n" |
| " jo 0b" |
| : "+&a" (dest), "+&a" (src) : "d" (r0) |
| : "cc", "memory" ); |
| return ret; |
| } |
| EXPORT_SYMBOL(strcpy); |
| #endif |
| |
| /** |
| * strlcpy - Copy a %NUL terminated string into a sized buffer |
| * @dest: Where to copy the string to |
| * @src: Where to copy the string from |
| * @size: size of destination buffer |
| * |
| * Compatible with *BSD: the result is always a valid |
| * NUL-terminated string that fits in the buffer (unless, |
| * of course, the buffer size is zero). It does not pad |
| * out the result like strncpy() does. |
| */ |
| #ifdef __HAVE_ARCH_STRLCPY |
| size_t strlcpy(char *dest, const char *src, size_t size) |
| { |
| size_t ret = __strend(src) - src; |
| |
| if (size) { |
| size_t len = (ret >= size) ? size-1 : ret; |
| dest[len] = '\0'; |
| memcpy(dest, src, len); |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(strlcpy); |
| #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) |
| { |
| register int r0 asm("0") = 0; |
| unsigned long dummy; |
| char *ret = dest; |
| |
| asm volatile ("0: srst %0,%1\n" |
| " jo 0b\n" |
| "1: mvst %0,%2\n" |
| " jo 1b" |
| : "=&a" (dummy), "+a" (dest), "+a" (src) |
| : "d" (r0), "0" (0UL) : "cc", "memory" ); |
| 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) |
| { |
| register int r0 asm("0") = 0; |
| int ret = 0; |
| |
| asm volatile ("0: clst %2,%3\n" |
| " jo 0b\n" |
| " je 1f\n" |
| " ic %0,0(%2)\n" |
| " ic %1,0(%3)\n" |
| " sr %0,%1\n" |
| "1:" |
| : "+d" (ret), "+d" (r0), "+a" (s1), "+a" (s2) |
| : : "cc", "memory"); |
| return ret; |
| } |
| EXPORT_SYMBOL(strcmp); |
| #endif |
| |
| /** |
| * strrchr - Find the last occurrence of a character in a string |
| * @s: The string to be searched |
| * @c: The character to search for |
| */ |
| #ifdef __HAVE_ARCH_STRRCHR |
| char *strrchr(const char *s, int c) |
| { |
| ssize_t len = __strend(s) - s; |
| |
| do { |
| if (s[len] == (char)c) |
| return (char *)s + len; |
| } while (--len >= 0); |
| return NULL; |
| } |
| EXPORT_SYMBOL(strrchr); |
| #endif |
| |
| static inline int clcle(const char *s1, unsigned long l1, |
| const char *s2, unsigned long l2) |
| { |
| register unsigned long r2 asm("2") = (unsigned long) s1; |
| register unsigned long r3 asm("3") = (unsigned long) l1; |
| register unsigned long r4 asm("4") = (unsigned long) s2; |
| register unsigned long r5 asm("5") = (unsigned long) l2; |
| int cc; |
| |
| asm volatile ("0: clcle %1,%3,0\n" |
| " jo 0b\n" |
| " ipm %0\n" |
| " srl %0,28" |
| : "=&d" (cc), "+a" (r2), "+a" (r3), |
| "+a" (r4), "+a" (r5) : : "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) |
| { |
| register int r0 asm("0") = (char) c; |
| const void *ret = s + n; |
| |
| asm volatile ("0: srst %0,%1\n" |
| " jo 0b\n" |
| " jl 1f\n" |
| " la %0,0\n" |
| "1:" |
| : "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory"); |
| 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) |
| { |
| register int r0 asm("0") = (char) c; |
| const void *ret = s + n; |
| |
| asm volatile ("0: srst %0,%1\n" |
| " jo 0b\n" |
| : "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory"); |
| return (void *) ret; |
| } |
| EXPORT_SYMBOL(memscan); |
| #endif |