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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 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);