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/cpufeatures.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:
  60                 __uaccess_begin();
  61                 __get_user_asm(*(u8 *)dst, (u8 __user *)src,
  62                               ret, "b", "b", "=q", 1);
  63                 __uaccess_end();
  64                 return ret;
  65         case 2:
  66                 __uaccess_begin();
  67                 __get_user_asm(*(u16 *)dst, (u16 __user *)src,
  68                               ret, "w", "w", "=r", 2);
  69                 __uaccess_end();
  70                 return ret;
  71         case 4:
  72                 __uaccess_begin();
  73                 __get_user_asm(*(u32 *)dst, (u32 __user *)src,
  74                               ret, "l", "k", "=r", 4);
  75                 __uaccess_end();
  76                 return ret;
  77         case 8:
  78                 __uaccess_begin();
  79                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
  80                               ret, "q", "", "=r", 8);
  81                 __uaccess_end();
  82                 return ret;
  83         case 10:
  84                 __uaccess_begin();
  85                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
  86                                ret, "q", "", "=r", 10);
  87                 if (likely(!ret))
  88                         __get_user_asm(*(u16 *)(8 + (char *)dst),
  89                                        (u16 __user *)(8 + (char __user *)src),
  90                                        ret, "w", "w", "=r", 2);
  91                 __uaccess_end();
  92                 return ret;
  93         case 16:
  94                 __uaccess_begin();
  95                 __get_user_asm(*(u64 *)dst, (u64 __user *)src,
  96                                ret, "q", "", "=r", 16);
  97                 if (likely(!ret))
  98                         __get_user_asm(*(u64 *)(8 + (char *)dst),
  99                                        (u64 __user *)(8 + (char __user *)src),
 100                                        ret, "q", "", "=r", 8);
 101                 __uaccess_end();
 102                 return ret;
 103         default:
 104                 return copy_user_generic(dst, (__force void *)src, size);
 105         }
 106 }
 107
 108 static __always_inline __must_check
 109 int __copy_from_user(void *dst, const void __user *src, unsigned size)
 110 {
 111         might_fault();
 112         return __copy_from_user_nocheck(dst, src, size);
 113 }
 114
 115 static __always_inline __must_check
 116 int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size)
 117 {
 118         int ret = 0;
 119
 120         if (!__builtin_constant_p(size))
 121                 return copy_user_generic((__force void *)dst, src, size);
 122         switch (size) {
 123         case 1:
 124                 __uaccess_begin();
 125                 __put_user_asm(*(u8 *)src, (u8 __user *)dst,
 126                               ret, "b", "b", "iq", 1);
 127                 __uaccess_end();
 128                 return ret;
 129         case 2:
 130                 __uaccess_begin();
 131                 __put_user_asm(*(u16 *)src, (u16 __user *)dst,
 132                               ret, "w", "w", "ir", 2);
 133                 __uaccess_end();
 134                 return ret;
 135         case 4:
 136                 __uaccess_begin();
 137                 __put_user_asm(*(u32 *)src, (u32 __user *)dst,
 138                               ret, "l", "k", "ir", 4);
 139                 __uaccess_end();
 140                 return ret;
 141         case 8:
 142                 __uaccess_begin();
 143                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 144                               ret, "q", "", "er", 8);
 145                 __uaccess_end();
 146                 return ret;
 147         case 10:
 148                 __uaccess_begin();
 149                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 150                                ret, "q", "", "er", 10);
 151                 if (likely(!ret)) {
 152                         asm("":::"memory");
 153                         __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
 154                                        ret, "w", "w", "ir", 2);
 155                 }
 156                 __uaccess_end();
 157                 return ret;
 158         case 16:
 159                 __uaccess_begin();
 160                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 161                                ret, "q", "", "er", 16);
 162                 if (likely(!ret)) {
 163                         asm("":::"memory");
 164                         __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
 165                                        ret, "q", "", "er", 8);
 166                 }
 167                 __uaccess_end();
 168                 return ret;
 169         default:
 170                 return copy_user_generic((__force void *)dst, src, size);
 171         }
 172 }
 173
 174 static __always_inline __must_check
 175 int __copy_to_user(void __user *dst, const void *src, unsigned size)
 176 {
 177         might_fault();
 178         return __copy_to_user_nocheck(dst, src, size);
 179 }
 180
 181 static __always_inline __must_check
 182 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 183 {
 184         int ret = 0;
 185
 186         might_fault();
 187         if (!__builtin_constant_p(size))
 188                 return copy_user_generic((__force void *)dst,
 189                                          (__force void *)src, size);
 190         switch (size) {
 191         case 1: {
 192                 u8 tmp;
 193                 __uaccess_begin();
 194                 __get_user_asm(tmp, (u8 __user *)src,
 195                                ret, "b", "b", "=q", 1);
 196                 if (likely(!ret))
 197                         __put_user_asm(tmp, (u8 __user *)dst,
 198                                        ret, "b", "b", "iq", 1);
 199                 __uaccess_end();
 200                 return ret;
 201         }
 202         case 2: {
 203                 u16 tmp;
 204                 __uaccess_begin();
 205                 __get_user_asm(tmp, (u16 __user *)src,
 206                                ret, "w", "w", "=r", 2);
 207                 if (likely(!ret))
 208                         __put_user_asm(tmp, (u16 __user *)dst,
 209                                        ret, "w", "w", "ir", 2);
 210                 __uaccess_end();
 211                 return ret;
 212         }
 213
 214         case 4: {
 215                 u32 tmp;
 216                 __uaccess_begin();
 217                 __get_user_asm(tmp, (u32 __user *)src,
 218                                ret, "l", "k", "=r", 4);
 219                 if (likely(!ret))
 220                         __put_user_asm(tmp, (u32 __user *)dst,
 221                                        ret, "l", "k", "ir", 4);
 222                 __uaccess_end();
 223                 return ret;
 224         }
 225         case 8: {
 226                 u64 tmp;
 227                 __uaccess_begin();
 228                 __get_user_asm(tmp, (u64 __user *)src,
 229                                ret, "q", "", "=r", 8);
 230                 if (likely(!ret))
 231                         __put_user_asm(tmp, (u64 __user *)dst,
 232                                        ret, "q", "", "er", 8);
 233                 __uaccess_end();
 234                 return ret;
 235         }
 236         default:
 237                 return copy_user_generic((__force void *)dst,
 238                                          (__force void *)src, size);
 239         }
 240 }
 241
 242 static __must_check __always_inline int
 243 __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
 244 {
 245         return __copy_from_user_nocheck(dst, src, size);
 246 }
 247
 248 static __must_check __always_inline int
 249 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
 250 {
 251         return __copy_to_user_nocheck(dst, src, size);
 252 }
 253
 254 extern long __copy_user_nocache(void *dst, const void __user *src,
 255                                 unsigned size, int zerorest);
 256
 257 static inline int
 258 __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
 259 {
 260         might_fault();
 261         return __copy_user_nocache(dst, src, size, 1);
 262 }
 263
 264 static inline int
 265 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
 266                                   unsigned size)
 267 {
 268         return __copy_user_nocache(dst, src, size, 0);
 269 }
 270
 271 unsigned long
 272 copy_user_handle_tail(char *to, char *from, unsigned len);
 273
 274 #endif /* _ASM_X86_UACCESS_64_H */