Loading...
1/*
2 * arch/s390/lib/string.c
3 * Optimized string functions
4 *
5 * S390 version
6 * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
8 */
9
10#define IN_ARCH_STRING_C 1
11
12#include <linux/types.h>
13#include <linux/module.h>
14
15/*
16 * Helper functions to find the end of a string
17 */
18static inline char *__strend(const char *s)
19{
20 register unsigned long r0 asm("0") = 0;
21
22 asm volatile ("0: srst %0,%1\n"
23 " jo 0b"
24 : "+d" (r0), "+a" (s) : : "cc" );
25 return (char *) r0;
26}
27
28static inline char *__strnend(const char *s, size_t n)
29{
30 register unsigned long r0 asm("0") = 0;
31 const char *p = s + n;
32
33 asm volatile ("0: srst %0,%1\n"
34 " jo 0b"
35 : "+d" (p), "+a" (s) : "d" (r0) : "cc" );
36 return (char *) p;
37}
38
39/**
40 * strlen - Find the length of a string
41 * @s: The string to be sized
42 *
43 * returns the length of @s
44 */
45size_t strlen(const char *s)
46{
47#if __GNUC__ < 4
48 return __strend(s) - s;
49#else
50 return __builtin_strlen(s);
51#endif
52}
53EXPORT_SYMBOL(strlen);
54
55/**
56 * strnlen - Find the length of a length-limited string
57 * @s: The string to be sized
58 * @n: The maximum number of bytes to search
59 *
60 * returns the minimum of the length of @s and @n
61 */
62size_t strnlen(const char * s, size_t n)
63{
64 return __strnend(s, n) - s;
65}
66EXPORT_SYMBOL(strnlen);
67
68/**
69 * strcpy - Copy a %NUL terminated string
70 * @dest: Where to copy the string to
71 * @src: Where to copy the string from
72 *
73 * returns a pointer to @dest
74 */
75char *strcpy(char *dest, const char *src)
76{
77#if __GNUC__ < 4
78 register int r0 asm("0") = 0;
79 char *ret = dest;
80
81 asm volatile ("0: mvst %0,%1\n"
82 " jo 0b"
83 : "+&a" (dest), "+&a" (src) : "d" (r0)
84 : "cc", "memory" );
85 return ret;
86#else
87 return __builtin_strcpy(dest, src);
88#endif
89}
90EXPORT_SYMBOL(strcpy);
91
92/**
93 * strlcpy - Copy a %NUL terminated string into a sized buffer
94 * @dest: Where to copy the string to
95 * @src: Where to copy the string from
96 * @size: size of destination buffer
97 *
98 * Compatible with *BSD: the result is always a valid
99 * NUL-terminated string that fits in the buffer (unless,
100 * of course, the buffer size is zero). It does not pad
101 * out the result like strncpy() does.
102 */
103size_t strlcpy(char *dest, const char *src, size_t size)
104{
105 size_t ret = __strend(src) - src;
106
107 if (size) {
108 size_t len = (ret >= size) ? size-1 : ret;
109 dest[len] = '\0';
110 __builtin_memcpy(dest, src, len);
111 }
112 return ret;
113}
114EXPORT_SYMBOL(strlcpy);
115
116/**
117 * strncpy - Copy a length-limited, %NUL-terminated string
118 * @dest: Where to copy the string to
119 * @src: Where to copy the string from
120 * @n: The maximum number of bytes to copy
121 *
122 * The result is not %NUL-terminated if the source exceeds
123 * @n bytes.
124 */
125char *strncpy(char *dest, const char *src, size_t n)
126{
127 size_t len = __strnend(src, n) - src;
128 __builtin_memset(dest + len, 0, n - len);
129 __builtin_memcpy(dest, src, len);
130 return dest;
131}
132EXPORT_SYMBOL(strncpy);
133
134/**
135 * strcat - Append one %NUL-terminated string to another
136 * @dest: The string to be appended to
137 * @src: The string to append to it
138 *
139 * returns a pointer to @dest
140 */
141char *strcat(char *dest, const char *src)
142{
143 register int r0 asm("0") = 0;
144 unsigned long dummy;
145 char *ret = dest;
146
147 asm volatile ("0: srst %0,%1\n"
148 " jo 0b\n"
149 "1: mvst %0,%2\n"
150 " jo 1b"
151 : "=&a" (dummy), "+a" (dest), "+a" (src)
152 : "d" (r0), "0" (0UL) : "cc", "memory" );
153 return ret;
154}
155EXPORT_SYMBOL(strcat);
156
157/**
158 * strlcat - Append a length-limited, %NUL-terminated string to another
159 * @dest: The string to be appended to
160 * @src: The string to append to it
161 * @n: The size of the destination buffer.
162 */
163size_t strlcat(char *dest, const char *src, size_t n)
164{
165 size_t dsize = __strend(dest) - dest;
166 size_t len = __strend(src) - src;
167 size_t res = dsize + len;
168
169 if (dsize < n) {
170 dest += dsize;
171 n -= dsize;
172 if (len >= n)
173 len = n - 1;
174 dest[len] = '\0';
175 __builtin_memcpy(dest, src, len);
176 }
177 return res;
178}
179EXPORT_SYMBOL(strlcat);
180
181/**
182 * strncat - Append a length-limited, %NUL-terminated string to another
183 * @dest: The string to be appended to
184 * @src: The string to append to it
185 * @n: The maximum numbers of bytes to copy
186 *
187 * returns a pointer to @dest
188 *
189 * Note that in contrast to strncpy, strncat ensures the result is
190 * terminated.
191 */
192char *strncat(char *dest, const char *src, size_t n)
193{
194 size_t len = __strnend(src, n) - src;
195 char *p = __strend(dest);
196
197 p[len] = '\0';
198 __builtin_memcpy(p, src, len);
199 return dest;
200}
201EXPORT_SYMBOL(strncat);
202
203/**
204 * strcmp - Compare two strings
205 * @cs: One string
206 * @ct: Another string
207 *
208 * returns 0 if @cs and @ct are equal,
209 * < 0 if @cs is less than @ct
210 * > 0 if @cs is greater than @ct
211 */
212int strcmp(const char *cs, const char *ct)
213{
214 register int r0 asm("0") = 0;
215 int ret = 0;
216
217 asm volatile ("0: clst %2,%3\n"
218 " jo 0b\n"
219 " je 1f\n"
220 " ic %0,0(%2)\n"
221 " ic %1,0(%3)\n"
222 " sr %0,%1\n"
223 "1:"
224 : "+d" (ret), "+d" (r0), "+a" (cs), "+a" (ct)
225 : : "cc" );
226 return ret;
227}
228EXPORT_SYMBOL(strcmp);
229
230/**
231 * strrchr - Find the last occurrence of a character in a string
232 * @s: The string to be searched
233 * @c: The character to search for
234 */
235char * strrchr(const char * s, int c)
236{
237 size_t len = __strend(s) - s;
238
239 if (len)
240 do {
241 if (s[len] == (char) c)
242 return (char *) s + len;
243 } while (--len > 0);
244 return NULL;
245}
246EXPORT_SYMBOL(strrchr);
247
248/**
249 * strstr - Find the first substring in a %NUL terminated string
250 * @s1: The string to be searched
251 * @s2: The string to search for
252 */
253char * strstr(const char * s1,const char * s2)
254{
255 int l1, l2;
256
257 l2 = __strend(s2) - s2;
258 if (!l2)
259 return (char *) s1;
260 l1 = __strend(s1) - s1;
261 while (l1-- >= l2) {
262 register unsigned long r2 asm("2") = (unsigned long) s1;
263 register unsigned long r3 asm("3") = (unsigned long) l2;
264 register unsigned long r4 asm("4") = (unsigned long) s2;
265 register unsigned long r5 asm("5") = (unsigned long) l2;
266 int cc;
267
268 asm volatile ("0: clcle %1,%3,0\n"
269 " jo 0b\n"
270 " ipm %0\n"
271 " srl %0,28"
272 : "=&d" (cc), "+a" (r2), "+a" (r3),
273 "+a" (r4), "+a" (r5) : : "cc" );
274 if (!cc)
275 return (char *) s1;
276 s1++;
277 }
278 return NULL;
279}
280EXPORT_SYMBOL(strstr);
281
282/**
283 * memchr - Find a character in an area of memory.
284 * @s: The memory area
285 * @c: The byte to search for
286 * @n: The size of the area.
287 *
288 * returns the address of the first occurrence of @c, or %NULL
289 * if @c is not found
290 */
291void *memchr(const void *s, int c, size_t n)
292{
293 register int r0 asm("0") = (char) c;
294 const void *ret = s + n;
295
296 asm volatile ("0: srst %0,%1\n"
297 " jo 0b\n"
298 " jl 1f\n"
299 " la %0,0\n"
300 "1:"
301 : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
302 return (void *) ret;
303}
304EXPORT_SYMBOL(memchr);
305
306/**
307 * memcmp - Compare two areas of memory
308 * @cs: One area of memory
309 * @ct: Another area of memory
310 * @count: The size of the area.
311 */
312int memcmp(const void *cs, const void *ct, size_t n)
313{
314 register unsigned long r2 asm("2") = (unsigned long) cs;
315 register unsigned long r3 asm("3") = (unsigned long) n;
316 register unsigned long r4 asm("4") = (unsigned long) ct;
317 register unsigned long r5 asm("5") = (unsigned long) n;
318 int ret;
319
320 asm volatile ("0: clcle %1,%3,0\n"
321 " jo 0b\n"
322 " ipm %0\n"
323 " srl %0,28"
324 : "=&d" (ret), "+a" (r2), "+a" (r3), "+a" (r4), "+a" (r5)
325 : : "cc" );
326 if (ret)
327 ret = *(char *) r2 - *(char *) r4;
328 return ret;
329}
330EXPORT_SYMBOL(memcmp);
331
332/**
333 * memscan - Find a character in an area of memory.
334 * @s: The memory area
335 * @c: The byte to search for
336 * @n: The size of the area.
337 *
338 * returns the address of the first occurrence of @c, or 1 byte past
339 * the area if @c is not found
340 */
341void *memscan(void *s, int c, size_t n)
342{
343 register int r0 asm("0") = (char) c;
344 const void *ret = s + n;
345
346 asm volatile ("0: srst %0,%1\n"
347 " jo 0b\n"
348 : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
349 return (void *) ret;
350}
351EXPORT_SYMBOL(memscan);
352
353/**
354 * memcpy - Copy one area of memory to another
355 * @dest: Where to copy to
356 * @src: Where to copy from
357 * @n: The size of the area.
358 *
359 * returns a pointer to @dest
360 */
361void *memcpy(void *dest, const void *src, size_t n)
362{
363 return __builtin_memcpy(dest, src, n);
364}
365EXPORT_SYMBOL(memcpy);
366
367/**
368 * memset - Fill a region of memory with the given value
369 * @s: Pointer to the start of the area.
370 * @c: The byte to fill the area with
371 * @n: The size of the area.
372 *
373 * returns a pointer to @s
374 */
375void *memset(void *s, int c, size_t n)
376{
377 char *xs;
378
379 if (c == 0)
380 return __builtin_memset(s, 0, n);
381
382 xs = (char *) s;
383 if (n > 0)
384 do {
385 *xs++ = c;
386 } while (--n > 0);
387 return s;
388}
389EXPORT_SYMBOL(memset);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Optimized string functions
4 *
5 * S390 version
6 * Copyright IBM Corp. 2004
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
8 */
9
10#define IN_ARCH_STRING_C 1
11#ifndef __NO_FORTIFY
12# define __NO_FORTIFY
13#endif
14
15#include <linux/types.h>
16#include <linux/string.h>
17#include <linux/export.h>
18
19/*
20 * Helper functions to find the end of a string
21 */
22static inline char *__strend(const char *s)
23{
24 unsigned long e = 0;
25
26 asm volatile(
27 " lghi 0,0\n"
28 "0: srst %[e],%[s]\n"
29 " jo 0b\n"
30 : [e] "+&a" (e), [s] "+&a" (s)
31 :
32 : "cc", "memory", "0");
33 return (char *)e;
34}
35
36static inline char *__strnend(const char *s, size_t n)
37{
38 const char *p = s + n;
39
40 asm volatile(
41 " lghi 0,0\n"
42 "0: srst %[p],%[s]\n"
43 " jo 0b\n"
44 : [p] "+&d" (p), [s] "+&a" (s)
45 :
46 : "cc", "memory", "0");
47 return (char *)p;
48}
49
50/**
51 * strlen - Find the length of a string
52 * @s: The string to be sized
53 *
54 * returns the length of @s
55 */
56#ifdef __HAVE_ARCH_STRLEN
57size_t strlen(const char *s)
58{
59 return __strend(s) - s;
60}
61EXPORT_SYMBOL(strlen);
62#endif
63
64/**
65 * strnlen - Find the length of a length-limited string
66 * @s: The string to be sized
67 * @n: The maximum number of bytes to search
68 *
69 * returns the minimum of the length of @s and @n
70 */
71#ifdef __HAVE_ARCH_STRNLEN
72size_t strnlen(const char *s, size_t n)
73{
74 return __strnend(s, n) - s;
75}
76EXPORT_SYMBOL(strnlen);
77#endif
78
79/**
80 * strcpy - Copy a %NUL terminated string
81 * @dest: Where to copy the string to
82 * @src: Where to copy the string from
83 *
84 * returns a pointer to @dest
85 */
86#ifdef __HAVE_ARCH_STRCPY
87char *strcpy(char *dest, const char *src)
88{
89 char *ret = dest;
90
91 asm volatile(
92 " lghi 0,0\n"
93 "0: mvst %[dest],%[src]\n"
94 " jo 0b\n"
95 : [dest] "+&a" (dest), [src] "+&a" (src)
96 :
97 : "cc", "memory", "0");
98 return ret;
99}
100EXPORT_SYMBOL(strcpy);
101#endif
102
103/**
104 * strncpy - Copy a length-limited, %NUL-terminated string
105 * @dest: Where to copy the string to
106 * @src: Where to copy the string from
107 * @n: The maximum number of bytes to copy
108 *
109 * The result is not %NUL-terminated if the source exceeds
110 * @n bytes.
111 */
112#ifdef __HAVE_ARCH_STRNCPY
113char *strncpy(char *dest, const char *src, size_t n)
114{
115 size_t len = __strnend(src, n) - src;
116 memset(dest + len, 0, n - len);
117 memcpy(dest, src, len);
118 return dest;
119}
120EXPORT_SYMBOL(strncpy);
121#endif
122
123/**
124 * strcat - Append one %NUL-terminated string to another
125 * @dest: The string to be appended to
126 * @src: The string to append to it
127 *
128 * returns a pointer to @dest
129 */
130#ifdef __HAVE_ARCH_STRCAT
131char *strcat(char *dest, const char *src)
132{
133 unsigned long dummy = 0;
134 char *ret = dest;
135
136 asm volatile(
137 " lghi 0,0\n"
138 "0: srst %[dummy],%[dest]\n"
139 " jo 0b\n"
140 "1: mvst %[dummy],%[src]\n"
141 " jo 1b\n"
142 : [dummy] "+&a" (dummy), [dest] "+&a" (dest), [src] "+&a" (src)
143 :
144 : "cc", "memory", "0");
145 return ret;
146}
147EXPORT_SYMBOL(strcat);
148#endif
149
150/**
151 * strlcat - Append a length-limited, %NUL-terminated string to another
152 * @dest: The string to be appended to
153 * @src: The string to append to it
154 * @n: The size of the destination buffer.
155 */
156#ifdef __HAVE_ARCH_STRLCAT
157size_t strlcat(char *dest, const char *src, size_t n)
158{
159 size_t dsize = __strend(dest) - dest;
160 size_t len = __strend(src) - src;
161 size_t res = dsize + len;
162
163 if (dsize < n) {
164 dest += dsize;
165 n -= dsize;
166 if (len >= n)
167 len = n - 1;
168 dest[len] = '\0';
169 memcpy(dest, src, len);
170 }
171 return res;
172}
173EXPORT_SYMBOL(strlcat);
174#endif
175
176/**
177 * strncat - Append a length-limited, %NUL-terminated string to another
178 * @dest: The string to be appended to
179 * @src: The string to append to it
180 * @n: The maximum numbers of bytes to copy
181 *
182 * returns a pointer to @dest
183 *
184 * Note that in contrast to strncpy, strncat ensures the result is
185 * terminated.
186 */
187#ifdef __HAVE_ARCH_STRNCAT
188char *strncat(char *dest, const char *src, size_t n)
189{
190 size_t len = __strnend(src, n) - src;
191 char *p = __strend(dest);
192
193 p[len] = '\0';
194 memcpy(p, src, len);
195 return dest;
196}
197EXPORT_SYMBOL(strncat);
198#endif
199
200/**
201 * strcmp - Compare two strings
202 * @s1: One string
203 * @s2: Another string
204 *
205 * returns 0 if @s1 and @s2 are equal,
206 * < 0 if @s1 is less than @s2
207 * > 0 if @s1 is greater than @s2
208 */
209#ifdef __HAVE_ARCH_STRCMP
210int strcmp(const char *s1, const char *s2)
211{
212 int ret = 0;
213
214 asm volatile(
215 " lghi 0,0\n"
216 "0: clst %[s1],%[s2]\n"
217 " jo 0b\n"
218 " je 1f\n"
219 " ic %[ret],0(%[s1])\n"
220 " ic 0,0(%[s2])\n"
221 " sr %[ret],0\n"
222 "1:"
223 : [ret] "+&d" (ret), [s1] "+&a" (s1), [s2] "+&a" (s2)
224 :
225 : "cc", "memory", "0");
226 return ret;
227}
228EXPORT_SYMBOL(strcmp);
229#endif
230
231static inline int clcle(const char *s1, unsigned long l1,
232 const char *s2, unsigned long l2)
233{
234 union register_pair r1 = { .even = (unsigned long)s1, .odd = l1, };
235 union register_pair r3 = { .even = (unsigned long)s2, .odd = l2, };
236 int cc;
237
238 asm volatile(
239 "0: clcle %[r1],%[r3],0\n"
240 " jo 0b\n"
241 " ipm %[cc]\n"
242 " srl %[cc],28\n"
243 : [cc] "=&d" (cc), [r1] "+&d" (r1.pair), [r3] "+&d" (r3.pair)
244 :
245 : "cc", "memory");
246 return cc;
247}
248
249/**
250 * strstr - Find the first substring in a %NUL terminated string
251 * @s1: The string to be searched
252 * @s2: The string to search for
253 */
254#ifdef __HAVE_ARCH_STRSTR
255char *strstr(const char *s1, const char *s2)
256{
257 int l1, l2;
258
259 l2 = __strend(s2) - s2;
260 if (!l2)
261 return (char *) s1;
262 l1 = __strend(s1) - s1;
263 while (l1-- >= l2) {
264 int cc;
265
266 cc = clcle(s1, l2, s2, l2);
267 if (!cc)
268 return (char *) s1;
269 s1++;
270 }
271 return NULL;
272}
273EXPORT_SYMBOL(strstr);
274#endif
275
276/**
277 * memchr - Find a character in an area of memory.
278 * @s: The memory area
279 * @c: The byte to search for
280 * @n: The size of the area.
281 *
282 * returns the address of the first occurrence of @c, or %NULL
283 * if @c is not found
284 */
285#ifdef __HAVE_ARCH_MEMCHR
286void *memchr(const void *s, int c, size_t n)
287{
288 const void *ret = s + n;
289
290 asm volatile(
291 " lgr 0,%[c]\n"
292 "0: srst %[ret],%[s]\n"
293 " jo 0b\n"
294 " jl 1f\n"
295 " la %[ret],0\n"
296 "1:"
297 : [ret] "+&a" (ret), [s] "+&a" (s)
298 : [c] "d" (c)
299 : "cc", "memory", "0");
300 return (void *) ret;
301}
302EXPORT_SYMBOL(memchr);
303#endif
304
305/**
306 * memcmp - Compare two areas of memory
307 * @s1: One area of memory
308 * @s2: Another area of memory
309 * @n: The size of the area.
310 */
311#ifdef __HAVE_ARCH_MEMCMP
312int memcmp(const void *s1, const void *s2, size_t n)
313{
314 int ret;
315
316 ret = clcle(s1, n, s2, n);
317 if (ret)
318 ret = ret == 1 ? -1 : 1;
319 return ret;
320}
321EXPORT_SYMBOL(memcmp);
322#endif
323
324/**
325 * memscan - Find a character in an area of memory.
326 * @s: The memory area
327 * @c: The byte to search for
328 * @n: The size of the area.
329 *
330 * returns the address of the first occurrence of @c, or 1 byte past
331 * the area if @c is not found
332 */
333#ifdef __HAVE_ARCH_MEMSCAN
334void *memscan(void *s, int c, size_t n)
335{
336 const void *ret = s + n;
337
338 asm volatile(
339 " lgr 0,%[c]\n"
340 "0: srst %[ret],%[s]\n"
341 " jo 0b\n"
342 : [ret] "+&a" (ret), [s] "+&a" (s)
343 : [c] "d" (c)
344 : "cc", "memory", "0");
345 return (void *)ret;
346}
347EXPORT_SYMBOL(memscan);
348#endif