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