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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
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
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);