1 #include <linux/string.h>
2 #include <linux/module.h>
5 #define movs(type,to,from) \
6 asm volatile("movs" type:"=&D" (to), "=&S" (from):"0" (to), "1" (from):"memory")
8 /* Originally from i386/string.h */
9 static __always_inline void rep_movs(void *to, const void *from, size_t n)
11 unsigned long d0, d1, d2;
12 asm volatile("rep ; movsl\n\t"
16 "1:\ttestb $1,%b4\n\t"
20 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
21 : "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
25 static void string_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
30 /* Align any unaligned source IO */
31 if (unlikely(1 & (unsigned long)from)) {
35 if (n > 1 && unlikely(2 & (unsigned long)from)) {
39 rep_movs(to, (const void *)from, n);
42 static void string_memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
47 /* Align any unaligned destination IO */
48 if (unlikely(1 & (unsigned long)to)) {
52 if (n > 1 && unlikely(2 & (unsigned long)to)) {
56 rep_movs((void *)to, (const void *) from, n);
59 static void unrolled_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
61 const volatile char __iomem *in = from;
65 for (i = 0; i < n; ++i)
66 out[i] = readb(&in[i]);
69 static void unrolled_memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
71 volatile char __iomem *out = to;
72 const char *in = from;
75 for (i = 0; i < n; ++i)
76 writeb(in[i], &out[i]);
79 static void unrolled_memset_io(volatile void __iomem *a, int b, size_t c)
81 volatile char __iomem *mem = a;
84 for (i = 0; i < c; ++i)
88 void memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
90 if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO))
91 unrolled_memcpy_fromio(to, from, n);
93 string_memcpy_fromio(to, from, n);
95 EXPORT_SYMBOL(memcpy_fromio);
97 void memcpy_toio(volatile void __iomem *to, const void *from, size_t n)
99 if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO))
100 unrolled_memcpy_toio(to, from, n);
102 string_memcpy_toio(to, from, n);
104 EXPORT_SYMBOL(memcpy_toio);
106 void memset_io(volatile void __iomem *a, int b, size_t c)
108 if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) {
109 unrolled_memset_io(a, b, c);
112 * TODO: memset can mangle the IO patterns quite a bit.
113 * perhaps it would be better to use a dumb one:
115 memset((void *)a, b, c);
118 EXPORT_SYMBOL(memset_io);