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\n\t"
169		     "stosb"
170		     : "=&c" (d0), "=&D" (d1)
171		     : "a" (c), "1" (s), "0" (count)
172		     : "memory");
173	return s;
174}
175
176/* we might want to write optimized versions of these later */
177#define __constant_count_memset(s, c, count) __memset_generic((s), (c), (count))
178
179/* Added by Gertjan van Wingerde to make minix and sysv module work */
180#define __HAVE_ARCH_STRNLEN
181extern size_t strnlen(const char *s, size_t count);
182/* end of additional stuff */
183
184#define __HAVE_ARCH_STRSTR
185extern char *strstr(const char *cs, const char *ct);
186
187#define __memset(s, c, count)				\
188	(__builtin_constant_p(count)			\
189	 ? __constant_count_memset((s), (c), (count))	\
190	 : __memset_generic((s), (c), (count)))
191
192#define __HAVE_ARCH_MEMSET
193extern void *memset(void *, int, size_t);
194#ifndef CONFIG_FORTIFY_SOURCE
195#define memset(s, c, count) __builtin_memset(s, c, count)
196#endif /* !CONFIG_FORTIFY_SOURCE */
197
198#define __HAVE_ARCH_MEMSET16
199static inline void *memset16(uint16_t *s, uint16_t v, size_t n)
200{
201	int d0, d1;
202	asm volatile("rep\n\t"
203		     "stosw"
204		     : "=&c" (d0), "=&D" (d1)
205		     : "a" (v), "1" (s), "0" (n)
206		     : "memory");
207	return s;
208}
209
210#define __HAVE_ARCH_MEMSET32
211static inline void *memset32(uint32_t *s, uint32_t v, size_t n)
212{
213	int d0, d1;
214	asm volatile("rep\n\t"
215		     "stosl"
216		     : "=&c" (d0), "=&D" (d1)
217		     : "a" (v), "1" (s), "0" (n)
218		     : "memory");
219	return s;
220}
221
222/*
223 * find the first occurrence of byte 'c', or 1 past the area if none
224 */
225#define __HAVE_ARCH_MEMSCAN
226extern void *memscan(void *addr, int c, size_t size);
227
228#endif /* __KERNEL__ */
229
230#endif /* _ASM_X86_STRING_32_H */
231