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