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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#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