1 #include <linux/string.h> 2 #include <linux/module.h> 3 #include <linux/io.h> 4 #include <linux/kmsan-checks.h> 5 6 #define movs(type,to,from) \ 7 asm volatile("movs" type:"=&D" (to), "=&S" (from):"0" (to), "1" (from):"memory") 8 9 /* Originally from i386/string.h */ 10 static __always_inline void rep_movs(void *to, const void *from, size_t n) 11 { 12 unsigned long d0, d1, d2; 13 asm volatile("rep ; movsl\n\t" 14 "testb $2,%b4\n\t" 15 "je 1f\n\t" 16 "movsw\n" 17 "1:\ttestb $1,%b4\n\t" 18 "je 2f\n\t" 19 "movsb\n" 20 "2:" 21 : "=&c" (d0), "=&D" (d1), "=&S" (d2) 22 : "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from) 23 : "memory"); 24 } 25 26 static void string_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n) 27 { 28 const void *orig_to = to; 29 const size_t orig_n = n; 30 31 if (unlikely(!n)) 32 return; 33 34 /* Align any unaligned source IO */ 35 if (unlikely(1 & (unsigned long)from)) { 36 movs("b", to, from); 37 n--; 38 } 39 if (n > 1 && unlikely(2 & (unsigned long)from)) { 40 movs("w", to, from); 41 n-=2; 42 } 43 rep_movs(to, (const void *)from, n); 44 /* KMSAN must treat values read from devices as initialized. */ 45 kmsan_unpoison_memory(orig_to, orig_n); 46 } 47 48 static void string_memcpy_toio(volatile void __iomem *to, const void *from, size_t n) 49 { 50 if (unlikely(!n)) 51 return; 52 53 /* Make sure uninitialized memory isn't copied to devices. */ 54 kmsan_check_memory(from, n); 55 /* Align any unaligned destination IO */ 56 if (unlikely(1 & (unsigned long)to)) { 57 movs("b", to, from); 58 n--; 59 } 60 if (n > 1 && unlikely(2 & (unsigned long)to)) { 61 movs("w", to, from); 62 n-=2; 63 } 64 rep_movs((void *)to, (const void *) from, n); 65 } 66 67 static void unrolled_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n) 68 { 69 const volatile char __iomem *in = from; 70 char *out = to; 71 int i; 72 73 for (i = 0; i < n; ++i) 74 out[i] = readb(&in[i]); 75 } 76 77 static void unrolled_memcpy_toio(volatile void __iomem *to, const void *from, size_t n) 78 { 79 volatile char __iomem *out = to; 80 const char *in = from; 81 int i; 82 83 for (i = 0; i < n; ++i) 84 writeb(in[i], &out[i]); 85 } 86 87 static void unrolled_memset_io(volatile void __iomem *a, int b, size_t c) 88 { 89 volatile char __iomem *mem = a; 90 int i; 91 92 for (i = 0; i < c; ++i) 93 writeb(b, &mem[i]); 94 } 95 96 void memcpy_fromio(void *to, const volatile void __iomem *from, size_t n) 97 { 98 if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) 99 unrolled_memcpy_fromio(to, from, n); 100 else 101 string_memcpy_fromio(to, from, n); 102 } 103 EXPORT_SYMBOL(memcpy_fromio); 104 105 void memcpy_toio(volatile void __iomem *to, const void *from, size_t n) 106 { 107 if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) 108 unrolled_memcpy_toio(to, from, n); 109 else 110 string_memcpy_toio(to, from, n); 111 } 112 EXPORT_SYMBOL(memcpy_toio); 113 114 void memset_io(volatile void __iomem *a, int b, size_t c) 115 { 116 if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) { 117 unrolled_memset_io(a, b, c); 118 } else { 119 /* 120 * TODO: memset can mangle the IO patterns quite a bit. 121 * perhaps it would be better to use a dumb one: 122 */ 123 memset((void *)a, b, c); 124 } 125 } 126 EXPORT_SYMBOL(memset_io); 127