arch/x86/include/asm/string_64.h

   1 #ifndef _ASM_X86_STRING_64_H
   2 #define _ASM_X86_STRING_64_H
   3
   4 #ifdef __KERNEL__
   5 #include <linux/jump_label.h>
   6
   7 /* Written 2002 by Andi Kleen */
   8
   9 /* Only used for special circumstances. Stolen from i386/string.h */
  10 static __always_inline void *__inline_memcpy(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         return to;
  25 }
  26
  27 /* Even with __builtin_ the compiler may decide to use the out of line
  28    function. */
  29
  30 #define __HAVE_ARCH_MEMCPY 1
  31 extern void *memcpy(void *to, const void *from, size_t len);
  32 extern void *__memcpy(void *to, const void *from, size_t len);
  33
  34 #ifndef CONFIG_KMEMCHECK
  35 #if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
  36 #define memcpy(dst, src, len)                                   \
  37 ({                                                              \
  38         size_t __len = (len);                                   \
  39         void *__ret;                                            \
  40         if (__builtin_constant_p(len) && __len >= 64)           \
  41                 __ret = __memcpy((dst), (src), __len);          \
  42         else                                                    \
  43                 __ret = __builtin_memcpy((dst), (src), __len);  \
  44         __ret;                                                  \
  45 })
  46 #endif
  47 #else
  48 /*
  49  * kmemcheck becomes very happy if we use the REP instructions unconditionally,
  50  * because it means that we know both memory operands in advance.
  51  */
  52 #define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
  53 #endif
  54
  55 #define __HAVE_ARCH_MEMSET
  56 void *memset(void *s, int c, size_t n);
  57 void *__memset(void *s, int c, size_t n);
  58
  59 #define __HAVE_ARCH_MEMMOVE
  60 void *memmove(void *dest, const void *src, size_t count);
  61 void *__memmove(void *dest, const void *src, size_t count);
  62
  63 int memcmp(const void *cs, const void *ct, size_t count);
  64 size_t strlen(const char *s);
  65 char *strcpy(char *dest, const char *src);
  66 char *strcat(char *dest, const char *src);
  67 int strcmp(const char *cs, const char *ct);
  68
  69 #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
  70
  71 /*
  72  * For files that not instrumented (e.g. mm/slub.c) we
  73  * should use not instrumented version of mem* functions.
  74  */
  75
  76 #undef memcpy
  77 #define memcpy(dst, src, len) __memcpy(dst, src, len)
  78 #define memmove(dst, src, len) __memmove(dst, src, len)
  79 #define memset(s, c, n) __memset(s, c, n)
  80 #endif
  81
  82 __must_check int memcpy_mcsafe_unrolled(void *dst, const void *src, size_t cnt);
  83 DECLARE_STATIC_KEY_FALSE(mcsafe_key);
  84
  85 /**
  86  * memcpy_mcsafe - copy memory with indication if a machine check happened
  87  *
  88  * @dst:        destination address
  89  * @src:        source address
  90  * @cnt:        number of bytes to copy
  91  *
  92  * Low level memory copy function that catches machine checks
  93  * We only call into the "safe" function on systems that can
  94  * actually do machine check recovery. Everyone else can just
  95  * use memcpy().
  96  *
  97  * Return 0 for success, -EFAULT for fail
  98  */
  99 static __always_inline __must_check int
 100 memcpy_mcsafe(void *dst, const void *src, size_t cnt)
 101 {
 102 #ifdef CONFIG_X86_MCE
 103         if (static_branch_unlikely(&mcsafe_key))
 104                 return memcpy_mcsafe_unrolled(dst, src, cnt);
 105         else
 106 #endif
 107                 memcpy(dst, src, cnt);
 108         return 0;
 109 }
 110
 111 #endif /* __KERNEL__ */
 112
 113 #endif /* _ASM_X86_STRING_64_H */