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_to_user(void __user *to, const void *from, unsigned len);
  50 __must_check unsigned long
  51 _copy_from_user(void *to, const void __user *from, unsigned len);
  52 __must_check unsigned long
  53 copy_in_user(void __user *to, const void __user *from, unsigned len);
  54
  55 static inline unsigned long __must_check copy_from_user(void *to,
  56                                           const void __user *from,
  57                                           unsigned long n)
  58 {
  59         int sz = __compiletime_object_size(to);
  60
  61         might_fault();
  62         if (likely(sz == -1 || sz >= n))
  63                 n = _copy_from_user(to, from, n);
  64 #ifdef CONFIG_DEBUG_VM
  65         else
  66                 WARN(1, "Buffer overflow detected!\n");
  67 #endif
  68         return n;
  69 }
  70
  71 static __always_inline __must_check
  72 int copy_to_user(void __user *dst, const void *src, unsigned size)
  73 {
  74         might_fault();
  75
  76         return _copy_to_user(dst, src, size);
  77 }
  78
  79 static __always_inline __must_check
  80 int __copy_from_user(void *dst, const void __user *src, unsigned size)
  81 {
  82         int ret = 0;
  83
  84         might_fault();
  85         if (!__builtin_constant_p(size))
  86                 return copy_user_generic(dst, (__force void *)src, size);
  87         switch (size) {
  88         case 1:__get_user_asm(*(u8 *)dst, (u8 __user *)src,
  89                               ret, "b", "b", "=q", 1);
  90                 return ret;
  91         case 2:__get_user_asm(*(u16 *)dst, (u16 __user *)src,
  92                               ret, "w", "w", "=r", 2);
  93                 return ret;
  94         case 4:__get_user_asm(*(u32 *)dst, (u32 __user *)src,
  95                               ret, "l", "k", "=r", 4);
  96                 return ret;
  97         case 8:__get_user_asm(*(u64 *)dst, (u64 __user *)src,
  98                               ret, "q", "", "=r", 8);
  99                 return ret;
 100         case 10:
 101                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
 102                                ret, "q", "", "=r", 10);
 103                 if (unlikely(ret))
 104                         return ret;
 105                 __get_user_asm(*(u16 *)(8 + (char *)dst),
 106                                (u16 __user *)(8 + (char __user *)src),
 107                                ret, "w", "w", "=r", 2);
 108                 return ret;
 109         case 16:
 110                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
 111                                ret, "q", "", "=r", 16);
 112                 if (unlikely(ret))
 113                         return ret;
 114                 __get_user_asm(*(u64 *)(8 + (char *)dst),
 115                                (u64 __user *)(8 + (char __user *)src),
 116                                ret, "q", "", "=r", 8);
 117                 return ret;
 118         default:
 119                 return copy_user_generic(dst, (__force void *)src, size);
 120         }
 121 }
 122
 123 static __always_inline __must_check
 124 int __copy_to_user(void __user *dst, const void *src, unsigned size)
 125 {
 126         int ret = 0;
 127
 128         might_fault();
 129         if (!__builtin_constant_p(size))
 130                 return copy_user_generic((__force void *)dst, src, size);
 131         switch (size) {
 132         case 1:__put_user_asm(*(u8 *)src, (u8 __user *)dst,
 133                               ret, "b", "b", "iq", 1);
 134                 return ret;
 135         case 2:__put_user_asm(*(u16 *)src, (u16 __user *)dst,
 136                               ret, "w", "w", "ir", 2);
 137                 return ret;
 138         case 4:__put_user_asm(*(u32 *)src, (u32 __user *)dst,
 139                               ret, "l", "k", "ir", 4);
 140                 return ret;
 141         case 8:__put_user_asm(*(u64 *)src, (u64 __user *)dst,
 142                               ret, "q", "", "er", 8);
 143                 return ret;
 144         case 10:
 145                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 146                                ret, "q", "", "er", 10);
 147                 if (unlikely(ret))
 148                         return ret;
 149                 asm("":::"memory");
 150                 __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
 151                                ret, "w", "w", "ir", 2);
 152                 return ret;
 153         case 16:
 154                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 155                                ret, "q", "", "er", 16);
 156                 if (unlikely(ret))
 157                         return ret;
 158                 asm("":::"memory");
 159                 __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
 160                                ret, "q", "", "er", 8);
 161                 return ret;
 162         default:
 163                 return copy_user_generic((__force void *)dst, src, size);
 164         }
 165 }
 166
 167 static __always_inline __must_check
 168 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 169 {
 170         int ret = 0;
 171
 172         might_fault();
 173         if (!__builtin_constant_p(size))
 174                 return copy_user_generic((__force void *)dst,
 175                                          (__force void *)src, size);
 176         switch (size) {
 177         case 1: {
 178                 u8 tmp;
 179                 __get_user_asm(tmp, (u8 __user *)src,
 180                                ret, "b", "b", "=q", 1);
 181                 if (likely(!ret))
 182                         __put_user_asm(tmp, (u8 __user *)dst,
 183                                        ret, "b", "b", "iq", 1);
 184                 return ret;
 185         }
 186         case 2: {
 187                 u16 tmp;
 188                 __get_user_asm(tmp, (u16 __user *)src,
 189                                ret, "w", "w", "=r", 2);
 190                 if (likely(!ret))
 191                         __put_user_asm(tmp, (u16 __user *)dst,
 192                                        ret, "w", "w", "ir", 2);
 193                 return ret;
 194         }
 195
 196         case 4: {
 197                 u32 tmp;
 198                 __get_user_asm(tmp, (u32 __user *)src,
 199                                ret, "l", "k", "=r", 4);
 200                 if (likely(!ret))
 201                         __put_user_asm(tmp, (u32 __user *)dst,
 202                                        ret, "l", "k", "ir", 4);
 203                 return ret;
 204         }
 205         case 8: {
 206                 u64 tmp;
 207                 __get_user_asm(tmp, (u64 __user *)src,
 208                                ret, "q", "", "=r", 8);
 209                 if (likely(!ret))
 210                         __put_user_asm(tmp, (u64 __user *)dst,
 211                                        ret, "q", "", "er", 8);
 212                 return ret;
 213         }
 214         default:
 215                 return copy_user_generic((__force void *)dst,
 216                                          (__force void *)src, size);
 217         }
 218 }
 219
 220 static __must_check __always_inline int
 221 __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
 222 {
 223         return copy_user_generic(dst, (__force const void *)src, size);
 224 }
 225
 226 static __must_check __always_inline int
 227 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
 228 {
 229         return copy_user_generic((__force void *)dst, src, size);
 230 }
 231
 232 extern long __copy_user_nocache(void *dst, const void __user *src,
 233                                 unsigned size, int zerorest);
 234
 235 static inline int
 236 __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
 237 {
 238         might_sleep();
 239         return __copy_user_nocache(dst, src, size, 1);
 240 }
 241
 242 static inline int
 243 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
 244                                   unsigned size)
 245 {
 246         return __copy_user_nocache(dst, src, size, 0);
 247 }
 248
 249 unsigned long
 250 copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest);
 251
 252 #endif /* _ASM_X86_UACCESS_64_H */