arch/x86/include/asm/uaccess_64.h

   1 #ifndef _ASM_X86_UACCESS_64_H
   2 #define _ASM_X86_UACCESS_64_H
   3
   4 /*
   5  * User space memory access functions
   6  */
   7 #include <linux/compiler.h>
   8 #include <linux/errno.h>
   9 #include <linux/lockdep.h>
  10 #include <asm/alternative.h>
  11 #include <asm/cpufeature.h>
  12 #include <asm/page.h>
  13
  14 /*
  15  * Copy To/From Userspace
  16  */
  17
  18 /* Handles exceptions in both to and from, but doesn't do access_ok */
  19 __must_check unsigned long
  20 copy_user_enhanced_fast_string(void *to, const void *from, unsigned len);
  21 __must_check unsigned long
  22 copy_user_generic_string(void *to, const void *from, unsigned len);
  23 __must_check unsigned long
  24 copy_user_generic_unrolled(void *to, const void *from, unsigned len);
  25
  26 static __always_inline __must_check unsigned long
  27 copy_user_generic(void *to, const void *from, unsigned len)
  28 {
  29         unsigned ret;
  30
  31         /*
  32          * If CPU has ERMS feature, use copy_user_enhanced_fast_string.
  33          * Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
  34          * Otherwise, use copy_user_generic_unrolled.
  35          */
  36         alternative_call_2(copy_user_generic_unrolled,
  37                          copy_user_generic_string,
  38                          X86_FEATURE_REP_GOOD,
  39                          copy_user_enhanced_fast_string,
  40                          X86_FEATURE_ERMS,
  41                          ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
  42                                      "=d" (len)),
  43                          "1" (to), "2" (from), "3" (len)
  44                          : "memory", "rcx", "r8", "r9", "r10", "r11");
  45         return ret;
  46 }
  47
  48 __must_check unsigned long
  49 copy_in_user(void __user *to, const void __user *from, unsigned len);
  50
  51 static __always_inline __must_check
  52 int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size)
  53 {
  54         int ret = 0;
  55
  56         if (!__builtin_constant_p(size))
  57                 return copy_user_generic(dst, (__force void *)src, size);
  58         switch (size) {
  59         case 1:__get_user_asm(*(u8 *)dst, (u8 __user *)src,
  60                               ret, "b", "b", "=q", 1);
  61                 return ret;
  62         case 2:__get_user_asm(*(u16 *)dst, (u16 __user *)src,
  63                               ret, "w", "w", "=r", 2);
  64                 return ret;
  65         case 4:__get_user_asm(*(u32 *)dst, (u32 __user *)src,
  66                               ret, "l", "k", "=r", 4);
  67                 return ret;
  68         case 8:__get_user_asm(*(u64 *)dst, (u64 __user *)src,
  69                               ret, "q", "", "=r", 8);
  70                 return ret;
  71         case 10:
  72                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
  73                                ret, "q", "", "=r", 10);
  74                 if (unlikely(ret))
  75                         return ret;
  76                 __get_user_asm(*(u16 *)(8 + (char *)dst),
  77                                (u16 __user *)(8 + (char __user *)src),
  78                                ret, "w", "w", "=r", 2);
  79                 return ret;
  80         case 16:
  81                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
  82                                ret, "q", "", "=r", 16);
  83                 if (unlikely(ret))
  84                         return ret;
  85                 __get_user_asm(*(u64 *)(8 + (char *)dst),
  86                                (u64 __user *)(8 + (char __user *)src),
  87                                ret, "q", "", "=r", 8);
  88                 return ret;
  89         default:
  90                 return copy_user_generic(dst, (__force void *)src, size);
  91         }
  92 }
  93
  94 static __always_inline __must_check
  95 int __copy_from_user(void *dst, const void __user *src, unsigned size)
  96 {
  97         might_fault();
  98         return __copy_from_user_nocheck(dst, src, size);
  99 }
 100
 101 static __always_inline __must_check
 102 int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size)
 103 {
 104         int ret = 0;
 105
 106         if (!__builtin_constant_p(size))
 107                 return copy_user_generic((__force void *)dst, src, size);
 108         switch (size) {
 109         case 1:__put_user_asm(*(u8 *)src, (u8 __user *)dst,
 110                               ret, "b", "b", "iq", 1);
 111                 return ret;
 112         case 2:__put_user_asm(*(u16 *)src, (u16 __user *)dst,
 113                               ret, "w", "w", "ir", 2);
 114                 return ret;
 115         case 4:__put_user_asm(*(u32 *)src, (u32 __user *)dst,
 116                               ret, "l", "k", "ir", 4);
 117                 return ret;
 118         case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst,
 119                               ret, "q", "", "er", 8);
 120                 return ret;
 121         case 10:
 122                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 123                                ret, "q", "", "er", 10);
 124                 if (unlikely(ret))
 125                         return ret;
 126                 asm("":::"memory");
 127                 __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
 128                                ret, "w", "w", "ir", 2);
 129                 return ret;
 130         case 16:
 131                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 132                                ret, "q", "", "er", 16);
 133                 if (unlikely(ret))
 134                         return ret;
 135                 asm("":::"memory");
 136                 __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
 137                                ret, "q", "", "er", 8);
 138                 return ret;
 139         default:
 140                 return copy_user_generic((__force void *)dst, src, size);
 141         }
 142 }
 143
 144 static __always_inline __must_check
 145 int __copy_to_user(void __user *dst, const void *src, unsigned size)
 146 {
 147         might_fault();
 148         return __copy_to_user_nocheck(dst, src, size);
 149 }
 150
 151 static __always_inline __must_check
 152 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 153 {
 154         int ret = 0;
 155
 156         might_fault();
 157         if (!__builtin_constant_p(size))
 158                 return copy_user_generic((__force void *)dst,
 159                                          (__force void *)src, size);
 160         switch (size) {
 161         case 1: {
 162                 u8 tmp;
 163                 __get_user_asm(tmp, (u8 __user *)src,
 164                                ret, "b", "b", "=q", 1);
 165                 if (likely(!ret))
 166                         __put_user_asm(tmp, (u8 __user *)dst,
 167                                        ret, "b", "b", "iq", 1);
 168                 return ret;
 169         }
 170         case 2: {
 171                 u16 tmp;
 172                 __get_user_asm(tmp, (u16 __user *)src,
 173                                ret, "w", "w", "=r", 2);
 174                 if (likely(!ret))
 175                         __put_user_asm(tmp, (u16 __user *)dst,
 176                                        ret, "w", "w", "ir", 2);
 177                 return ret;
 178         }
 179
 180         case 4: {
 181                 u32 tmp;
 182                 __get_user_asm(tmp, (u32 __user *)src,
 183                                ret, "l", "k", "=r", 4);
 184                 if (likely(!ret))
 185                         __put_user_asm(tmp, (u32 __user *)dst,
 186                                        ret, "l", "k", "ir", 4);
 187                 return ret;
 188         }
 189         case 8: {
 190                 u64 tmp;
 191                 __get_user_asm(tmp, (u64 __user *)src,
 192                                ret, "q", "", "=r", 8);
 193                 if (likely(!ret))
 194                         __put_user_asm(tmp, (u64 __user *)dst,
 195                                        ret, "q", "", "er", 8);
 196                 return ret;
 197         }
 198         default:
 199                 return copy_user_generic((__force void *)dst,
 200                                          (__force void *)src, size);
 201         }
 202 }
 203
 204 static __must_check __always_inline int
 205 __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
 206 {
 207         return __copy_from_user_nocheck(dst, src, size);
 208 }
 209
 210 static __must_check __always_inline int
 211 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
 212 {
 213         return __copy_to_user_nocheck(dst, src, size);
 214 }
 215
 216 extern long __copy_user_nocache(void *dst, const void __user *src,
 217                                 unsigned size, int zerorest);
 218
 219 static inline int
 220 __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
 221 {
 222         might_fault();
 223         return __copy_user_nocache(dst, src, size, 1);
 224 }
 225
 226 static inline int
 227 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
 228                                   unsigned size)
 229 {
 230         return __copy_user_nocache(dst, src, size, 0);
 231 }
 232
 233 unsigned long
 234 copy_user_handle_tail(char *to, char *from, unsigned len);
 235
 236 #endif /* _ASM_X86_UACCESS_64_H */