string_32.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_X86_STRING_32_H
  3#define _ASM_X86_STRING_32_H
  4
  5#ifdef __KERNEL__
  6
  7/* Let gcc decide whether to inline or use the out of line functions */
  8
  9#define __HAVE_ARCH_STRCPY
 10extern char *strcpy(char *dest, const char *src);
 11
 12#define __HAVE_ARCH_STRNCPY
 13extern char *strncpy(char *dest, const char *src, size_t count);
 14
 15#define __HAVE_ARCH_STRCAT
 16extern char *strcat(char *dest, const char *src);
 17
 18#define __HAVE_ARCH_STRNCAT
 19extern char *strncat(char *dest, const char *src, size_t count);
 20
 21#define __HAVE_ARCH_STRCMP
 22extern int strcmp(const char *cs, const char *ct);
 23
 24#define __HAVE_ARCH_STRNCMP
 25extern int strncmp(const char *cs, const char *ct, size_t count);
 26
 27#define __HAVE_ARCH_STRCHR
 28extern char *strchr(const char *s, int c);
 29
 30#define __HAVE_ARCH_STRLEN
 31extern size_t strlen(const char *s);
 32
 33static __always_inline void *__memcpy(void *to, const void *from, size_t n)
 34{
 35	int d0, d1, d2;
 36	asm volatile("rep movsl\n\t"
 37		     "movl %4,%%ecx\n\t"
 38		     "andl $3,%%ecx\n\t"
 39		     "jz 1f\n\t"
 40		     "rep movsb\n\t"
 41		     "1:"
 42		     : "=&c" (d0), "=&D" (d1), "=&S" (d2)
 43		     : "0" (n / 4), "g" (n), "1" ((long)to), "2" ((long)from)
 44		     : "memory");
 45	return to;
 46}
 47
 48/*
 49 * This looks ugly, but the compiler can optimize it totally,
 50 * as the count is constant.
 51 */
 52static __always_inline void *__constant_memcpy(void *to, const void *from,
 53					       size_t n)
 54{
 55	long esi, edi;
 56	if (!n)
 57		return to;
 58
 59	switch (n) {
 60	case 1:
 61		*(char *)to = *(char *)from;
 62		return to;
 63	case 2:
 64		*(short *)to = *(short *)from;
 65		return to;
 66	case 4:
 67		*(int *)to = *(int *)from;
 68		return to;
 69	case 3:
 70		*(short *)to = *(short *)from;
 71		*((char *)to + 2) = *((char *)from + 2);
 72		return to;
 73	case 5:
 74		*(int *)to = *(int *)from;
 75		*((char *)to + 4) = *((char *)from + 4);
 76		return to;
 77	case 6:
 78		*(int *)to = *(int *)from;
 79		*((short *)to + 2) = *((short *)from + 2);
 80		return to;
 81	case 8:
 82		*(int *)to = *(int *)from;
 83		*((int *)to + 1) = *((int *)from + 1);
 84		return to;
 85	}
 86
 87	esi = (long)from;
 88	edi = (long)to;
 89	if (n >= 5 * 4) {
 90		/* large block: use rep prefix */
 91		int ecx;
 92		asm volatile("rep movsl"
 93			     : "=&c" (ecx), "=&D" (edi), "=&S" (esi)
 94			     : "0" (n / 4), "1" (edi), "2" (esi)
 95			     : "memory"
 96		);
 97	} else {
 98		/* small block: don't clobber ecx + smaller code */
 99		if (n >= 4 * 4)
100			asm volatile("movsl"
101				     : "=&D"(edi), "=&S"(esi)
102				     : "0"(edi), "1"(esi)
103				     : "memory");
104		if (n >= 3 * 4)
105			asm volatile("movsl"
106				     : "=&D"(edi), "=&S"(esi)
107				     : "0"(edi), "1"(esi)
108				     : "memory");
109		if (n >= 2 * 4)
110			asm volatile("movsl"
111				     : "=&D"(edi), "=&S"(esi)
112				     : "0"(edi), "1"(esi)
113				     : "memory");
114		if (n >= 1 * 4)
115			asm volatile("movsl"
116				     : "=&D"(edi), "=&S"(esi)
117				     : "0"(edi), "1"(esi)
118				     : "memory");
119	}
120	switch (n % 4) {
121		/* tail */
122	case 0:
123		return to;
124	case 1:
125		asm volatile("movsb"
126			     : "=&D"(edi), "=&S"(esi)
127			     : "0"(edi), "1"(esi)
128			     : "memory");
129		return to;
130	case 2:
131		asm volatile("movsw"
132			     : "=&D"(edi), "=&S"(esi)
133			     : "0"(edi), "1"(esi)
134			     : "memory");
135		return to;
136	default:
137		asm volatile("movsw\n\tmovsb"
138			     : "=&D"(edi), "=&S"(esi)
139			     : "0"(edi), "1"(esi)
140			     : "memory");
141		return to;
142	}
143}
144
145#define __HAVE_ARCH_MEMCPY
146extern void *memcpy(void *, const void *, size_t);
147
148#ifndef CONFIG_FORTIFY_SOURCE
149
150#define memcpy(t, f, n) __builtin_memcpy(t, f, n)
151
152#endif /* !CONFIG_FORTIFY_SOURCE */
153
154#define __HAVE_ARCH_MEMMOVE
155void *memmove(void *dest, const void *src, size_t n);
156
157extern int memcmp(const void *, const void *, size_t);
158#ifndef CONFIG_FORTIFY_SOURCE
159#define memcmp __builtin_memcmp
160#endif
161
162#define __HAVE_ARCH_MEMCHR
163extern void *memchr(const void *cs, int c, size_t count);
164
165static inline void *__memset_generic(void *s, char c, size_t count)
166{
167	int d0, d1;
168	asm volatile("rep stosb"
169		     : "=&c" (d0), "=&D" (d1)
170		     : "a" (c), "1" (s), "0" (count)
171		     : "memory");
172	return s;
173}
174
175/* we might want to write optimized versions of these later */
176#define __constant_count_memset(s, c, count) __memset_generic((s), (c), (count))
177
178/* Added by Gertjan van Wingerde to make minix and sysv module work */
179#define __HAVE_ARCH_STRNLEN
180extern size_t strnlen(const char *s, size_t count);
181/* end of additional stuff */
182
183#define __HAVE_ARCH_STRSTR
184extern char *strstr(const char *cs, const char *ct);
185
186#define __memset(s, c, count)				\
187	(__builtin_constant_p(count)			\
188	 ? __constant_count_memset((s), (c), (count))	\
189	 : __memset_generic((s), (c), (count)))
190
191#define __HAVE_ARCH_MEMSET
192extern void *memset(void *, int, size_t);
193#ifndef CONFIG_FORTIFY_SOURCE
194#define memset(s, c, count) __builtin_memset(s, c, count)
195#endif /* !CONFIG_FORTIFY_SOURCE */
196
197#define __HAVE_ARCH_MEMSET16
198static inline void *memset16(uint16_t *s, uint16_t v, size_t n)
199{
200	int d0, d1;
201	asm volatile("rep stosw"
202		     : "=&c" (d0), "=&D" (d1)
203		     : "a" (v), "1" (s), "0" (n)
204		     : "memory");
205	return s;
206}
207
208#define __HAVE_ARCH_MEMSET32
209static inline void *memset32(uint32_t *s, uint32_t v, size_t n)
210{
211	int d0, d1;
212	asm volatile("rep stosl"
213		     : "=&c" (d0), "=&D" (d1)
214		     : "a" (v), "1" (s), "0" (n)
215		     : "memory");
216	return s;
217}
218
219/*
220 * find the first occurrence of byte 'c', or 1 past the area if none
221 */
222#define __HAVE_ARCH_MEMSCAN
223extern void *memscan(void *addr, int c, size_t size);
224
225#endif /* __KERNEL__ */
226
227#endif /* _ASM_X86_STRING_32_H */