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/lockdep.h>
   9 #include <linux/kasan-checks.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         check_object_size(dst, size, false);
  57         if (!__builtin_constant_p(size))
  58                 return copy_user_generic(dst, (__force void *)src, size);
  59         switch (size) {
  60         case 1:
  61                 __uaccess_begin();
  62                 __get_user_asm_nozero(*(u8 *)dst, (u8 __user *)src,
  63                               ret, "b", "b", "=q", 1);
  64                 __uaccess_end();
  65                 return ret;
  66         case 2:
  67                 __uaccess_begin();
  68                 __get_user_asm_nozero(*(u16 *)dst, (u16 __user *)src,
  69                               ret, "w", "w", "=r", 2);
  70                 __uaccess_end();
  71                 return ret;
  72         case 4:
  73                 __uaccess_begin();
  74                 __get_user_asm_nozero(*(u32 *)dst, (u32 __user *)src,
  75                               ret, "l", "k", "=r", 4);
  76                 __uaccess_end();
  77                 return ret;
  78         case 8:
  79                 __uaccess_begin();
  80                 __get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
  81                               ret, "q", "", "=r", 8);
  82                 __uaccess_end();
  83                 return ret;
  84         case 10:
  85                 __uaccess_begin();
  86                 __get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
  87                                ret, "q", "", "=r", 10);
  88                 if (likely(!ret))
  89                         __get_user_asm_nozero(*(u16 *)(8 + (char *)dst),
  90                                        (u16 __user *)(8 + (char __user *)src),
  91                                        ret, "w", "w", "=r", 2);
  92                 __uaccess_end();
  93                 return ret;
  94         case 16:
  95                 __uaccess_begin();
  96                 __get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
  97                                ret, "q", "", "=r", 16);
  98                 if (likely(!ret))
  99                         __get_user_asm_nozero(*(u64 *)(8 + (char *)dst),
 100                                        (u64 __user *)(8 + (char __user *)src),
 101                                        ret, "q", "", "=r", 8);
 102                 __uaccess_end();
 103                 return ret;
 104         default:
 105                 return copy_user_generic(dst, (__force void *)src, size);
 106         }
 107 }
 108
 109 static __always_inline __must_check
 110 int __copy_from_user(void *dst, const void __user *src, unsigned size)
 111 {
 112         might_fault();
 113         kasan_check_write(dst, size);
 114         return __copy_from_user_nocheck(dst, src, size);
 115 }
 116
 117 static __always_inline __must_check
 118 int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size)
 119 {
 120         int ret = 0;
 121
 122         check_object_size(src, size, true);
 123         if (!__builtin_constant_p(size))
 124                 return copy_user_generic((__force void *)dst, src, size);
 125         switch (size) {
 126         case 1:
 127                 __uaccess_begin();
 128                 __put_user_asm(*(u8 *)src, (u8 __user *)dst,
 129                               ret, "b", "b", "iq", 1);
 130                 __uaccess_end();
 131                 return ret;
 132         case 2:
 133                 __uaccess_begin();
 134                 __put_user_asm(*(u16 *)src, (u16 __user *)dst,
 135                               ret, "w", "w", "ir", 2);
 136                 __uaccess_end();
 137                 return ret;
 138         case 4:
 139                 __uaccess_begin();
 140                 __put_user_asm(*(u32 *)src, (u32 __user *)dst,
 141                               ret, "l", "k", "ir", 4);
 142                 __uaccess_end();
 143                 return ret;
 144         case 8:
 145                 __uaccess_begin();
 146                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 147                               ret, "q", "", "er", 8);
 148                 __uaccess_end();
 149                 return ret;
 150         case 10:
 151                 __uaccess_begin();
 152                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 153                                ret, "q", "", "er", 10);
 154                 if (likely(!ret)) {
 155                         asm("":::"memory");
 156                         __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
 157                                        ret, "w", "w", "ir", 2);
 158                 }
 159                 __uaccess_end();
 160                 return ret;
 161         case 16:
 162                 __uaccess_begin();
 163                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 164                                ret, "q", "", "er", 16);
 165                 if (likely(!ret)) {
 166                         asm("":::"memory");
 167                         __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
 168                                        ret, "q", "", "er", 8);
 169                 }
 170                 __uaccess_end();
 171                 return ret;
 172         default:
 173                 return copy_user_generic((__force void *)dst, src, size);
 174         }
 175 }
 176
 177 static __always_inline __must_check
 178 int __copy_to_user(void __user *dst, const void *src, unsigned size)
 179 {
 180         might_fault();
 181         kasan_check_read(src, size);
 182         return __copy_to_user_nocheck(dst, src, size);
 183 }
 184
 185 static __always_inline __must_check
 186 int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
 187 {
 188         int ret = 0;
 189
 190         might_fault();
 191         if (!__builtin_constant_p(size))
 192                 return copy_user_generic((__force void *)dst,
 193                                          (__force void *)src, size);
 194         switch (size) {
 195         case 1: {
 196                 u8 tmp;
 197                 __uaccess_begin();
 198                 __get_user_asm(tmp, (u8 __user *)src,
 199                                ret, "b", "b", "=q", 1);
 200                 if (likely(!ret))
 201                         __put_user_asm(tmp, (u8 __user *)dst,
 202                                        ret, "b", "b", "iq", 1);
 203                 __uaccess_end();
 204                 return ret;
 205         }
 206         case 2: {
 207                 u16 tmp;
 208                 __uaccess_begin();
 209                 __get_user_asm(tmp, (u16 __user *)src,
 210                                ret, "w", "w", "=r", 2);
 211                 if (likely(!ret))
 212                         __put_user_asm(tmp, (u16 __user *)dst,
 213                                        ret, "w", "w", "ir", 2);
 214                 __uaccess_end();
 215                 return ret;
 216         }
 217
 218         case 4: {
 219                 u32 tmp;
 220                 __uaccess_begin();
 221                 __get_user_asm(tmp, (u32 __user *)src,
 222                                ret, "l", "k", "=r", 4);
 223                 if (likely(!ret))
 224                         __put_user_asm(tmp, (u32 __user *)dst,
 225                                        ret, "l", "k", "ir", 4);
 226                 __uaccess_end();
 227                 return ret;
 228         }
 229         case 8: {
 230                 u64 tmp;
 231                 __uaccess_begin();
 232                 __get_user_asm(tmp, (u64 __user *)src,
 233                                ret, "q", "", "=r", 8);
 234                 if (likely(!ret))
 235                         __put_user_asm(tmp, (u64 __user *)dst,
 236                                        ret, "q", "", "er", 8);
 237                 __uaccess_end();
 238                 return ret;
 239         }
 240         default:
 241                 return copy_user_generic((__force void *)dst,
 242                                          (__force void *)src, size);
 243         }
 244 }
 245
 246 static __must_check __always_inline int
 247 __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
 248 {
 249         kasan_check_write(dst, size);
 250         return __copy_from_user_nocheck(dst, src, size);
 251 }
 252
 253 static __must_check __always_inline int
 254 __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
 255 {
 256         kasan_check_read(src, size);
 257         return __copy_to_user_nocheck(dst, src, size);
 258 }
 259
 260 extern long __copy_user_nocache(void *dst, const void __user *src,
 261                                 unsigned size, int zerorest);
 262
 263 static inline int
 264 __copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
 265 {
 266         might_fault();
 267         kasan_check_write(dst, size);
 268         return __copy_user_nocache(dst, src, size, 1);
 269 }
 270
 271 static inline int
 272 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
 273                                   unsigned size)
 274 {
 275         kasan_check_write(dst, size);
 276         return __copy_user_nocache(dst, src, size, 0);
 277 }
 278
 279 unsigned long
 280 copy_user_handle_tail(char *to, char *from, unsigned len);
 281
 282 #endif /* _ASM_X86_UACCESS_64_H */