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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#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#include <asm/asm.h>
19
20/*
21 * Helper functions to find the end of a string
22 */
23static inline char *__strend(const char *s)
24{
25 unsigned long e = 0;
26
27 asm volatile(
28 " lghi 0,0\n"
29 "0: srst %[e],%[s]\n"
30 " jo 0b\n"
31 : [e] "+&a" (e), [s] "+&a" (s)
32 :
33 : "cc", "memory", "0");
34 return (char *)e;
35}
36
37static inline char *__strnend(const char *s, size_t n)
38{
39 const char *p = s + n;
40
41 asm volatile(
42 " lghi 0,0\n"
43 "0: srst %[p],%[s]\n"
44 " jo 0b\n"
45 : [p] "+&d" (p), [s] "+&a" (s)
46 :
47 : "cc", "memory", "0");
48 return (char *)p;
49}
50
51/**
52 * strlen - Find the length of a string
53 * @s: The string to be sized
54 *
55 * returns the length of @s
56 */
57#ifdef __HAVE_ARCH_STRLEN
58size_t strlen(const char *s)
59{
60 return __strend(s) - s;
61}
62EXPORT_SYMBOL(strlen);
63#endif
64
65/**
66 * strnlen - Find the length of a length-limited string
67 * @s: The string to be sized
68 * @n: The maximum number of bytes to search
69 *
70 * returns the minimum of the length of @s and @n
71 */
72#ifdef __HAVE_ARCH_STRNLEN
73size_t strnlen(const char *s, size_t n)
74{
75 return __strnend(s, n) - s;
76}
77EXPORT_SYMBOL(strnlen);
78#endif
79
80/**
81 * strcpy - Copy a %NUL terminated string
82 * @dest: Where to copy the string to
83 * @src: Where to copy the string from
84 *
85 * returns a pointer to @dest
86 */
87#ifdef __HAVE_ARCH_STRCPY
88char *strcpy(char *dest, const char *src)
89{
90 char *ret = dest;
91
92 asm volatile(
93 " lghi 0,0\n"
94 "0: mvst %[dest],%[src]\n"
95 " jo 0b\n"
96 : [dest] "+&a" (dest), [src] "+&a" (src)
97 :
98 : "cc", "memory", "0");
99 return ret;
100}
101EXPORT_SYMBOL(strcpy);
102#endif
103
104/**
105 * strncpy - Copy a length-limited, %NUL-terminated string
106 * @dest: Where to copy the string to
107 * @src: Where to copy the string from
108 * @n: The maximum number of bytes to copy
109 *
110 * The result is not %NUL-terminated if the source exceeds
111 * @n bytes.
112 */
113#ifdef __HAVE_ARCH_STRNCPY
114char *strncpy(char *dest, const char *src, size_t n)
115{
116 size_t len = __strnend(src, n) - src;
117 memset(dest + len, 0, n - len);
118 memcpy(dest, src, len);
119 return dest;
120}
121EXPORT_SYMBOL(strncpy);
122#endif
123
124/**
125 * strcat - Append one %NUL-terminated string to another
126 * @dest: The string to be appended to
127 * @src: The string to append to it
128 *
129 * returns a pointer to @dest
130 */
131#ifdef __HAVE_ARCH_STRCAT
132char *strcat(char *dest, const char *src)
133{
134 unsigned long dummy = 0;
135 char *ret = dest;
136
137 asm volatile(
138 " lghi 0,0\n"
139 "0: srst %[dummy],%[dest]\n"
140 " jo 0b\n"
141 "1: mvst %[dummy],%[src]\n"
142 " jo 1b\n"
143 : [dummy] "+&a" (dummy), [dest] "+&a" (dest), [src] "+&a" (src)
144 :
145 : "cc", "memory", "0");
146 return ret;
147}
148EXPORT_SYMBOL(strcat);
149#endif
150
151/**
152 * strlcat - Append a length-limited, %NUL-terminated string to another
153 * @dest: The string to be appended to
154 * @src: The string to append to it
155 * @n: The size of the destination buffer.
156 */
157#ifdef __HAVE_ARCH_STRLCAT
158size_t strlcat(char *dest, const char *src, size_t n)
159{
160 size_t dsize = __strend(dest) - dest;
161 size_t len = __strend(src) - src;
162 size_t res = dsize + len;
163
164 if (dsize < n) {
165 dest += dsize;
166 n -= dsize;
167 if (len >= n)
168 len = n - 1;
169 dest[len] = '\0';
170 memcpy(dest, src, len);
171 }
172 return res;
173}
174EXPORT_SYMBOL(strlcat);
175#endif
176
177/**
178 * strncat - Append a length-limited, %NUL-terminated string to another
179 * @dest: The string to be appended to
180 * @src: The string to append to it
181 * @n: The maximum numbers of bytes to copy
182 *
183 * returns a pointer to @dest
184 *
185 * Note that in contrast to strncpy, strncat ensures the result is
186 * terminated.
187 */
188#ifdef __HAVE_ARCH_STRNCAT
189char *strncat(char *dest, const char *src, size_t n)
190{
191 size_t len = __strnend(src, n) - src;
192 char *p = __strend(dest);
193
194 p[len] = '\0';
195 memcpy(p, src, len);
196 return dest;
197}
198EXPORT_SYMBOL(strncat);
199#endif
200
201/**
202 * strcmp - Compare two strings
203 * @s1: One string
204 * @s2: Another string
205 *
206 * returns 0 if @s1 and @s2 are equal,
207 * < 0 if @s1 is less than @s2
208 * > 0 if @s1 is greater than @s2
209 */
210#ifdef __HAVE_ARCH_STRCMP
211int strcmp(const char *s1, const char *s2)
212{
213 int ret = 0;
214
215 asm volatile(
216 " lghi 0,0\n"
217 "0: clst %[s1],%[s2]\n"
218 " jo 0b\n"
219 " je 1f\n"
220 " ic %[ret],0(%[s1])\n"
221 " ic 0,0(%[s2])\n"
222 " sr %[ret],0\n"
223 "1:"
224 : [ret] "+&d" (ret), [s1] "+&a" (s1), [s2] "+&a" (s2)
225 :
226 : "cc", "memory", "0");
227 return ret;
228}
229EXPORT_SYMBOL(strcmp);
230#endif
231
232static inline int clcle(const char *s1, unsigned long l1,
233 const char *s2, unsigned long l2)
234{
235 union register_pair r1 = { .even = (unsigned long)s1, .odd = l1, };
236 union register_pair r3 = { .even = (unsigned long)s2, .odd = l2, };
237 int cc;
238
239 asm volatile(
240 "0: clcle %[r1],%[r3],0\n"
241 " jo 0b\n"
242 CC_IPM(cc)
243 : CC_OUT(cc, cc), [r1] "+d" (r1.pair), [r3] "+d" (r3.pair)
244 :
245 : CC_CLOBBER_LIST("memory"));
246 return CC_TRANSFORM(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
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