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