arch/x86/include/asm/uaccess_64.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_UACCESS_64_H
   3 #define _ASM_X86_UACCESS_64_H
   4
   5 /*
   6  * User space memory access functions
   7  */
   8 #include <linux/compiler.h>
   9 #include <linux/lockdep.h>
  10 #include <linux/kasan-checks.h>
  11 #include <asm/alternative.h>
  12 #include <asm/cpufeatures.h>
  13 #include <asm/page.h>
  14
  15 /*
  16  * Copy To/From Userspace
  17  */
  18
  19 /* Handles exceptions in both to and from, but doesn't do access_ok */
  20 __must_check unsigned long
  21 copy_user_enhanced_fast_string(void *to, const void *from, unsigned len);
  22 __must_check unsigned long
  23 copy_user_generic_string(void *to, const void *from, unsigned len);
  24 __must_check unsigned long
  25 copy_user_generic_unrolled(void *to, const void *from, unsigned len);
  26
  27 static __always_inline __must_check unsigned long
  28 copy_user_generic(void *to, const void *from, unsigned len)
  29 {
  30         unsigned ret;
  31
  32         /*
  33          * If CPU has ERMS feature, use copy_user_enhanced_fast_string.
  34          * Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
  35          * Otherwise, use copy_user_generic_unrolled.
  36          */
  37         alternative_call_2(copy_user_generic_unrolled,
  38                          copy_user_generic_string,
  39                          X86_FEATURE_REP_GOOD,
  40                          copy_user_enhanced_fast_string,
  41                          X86_FEATURE_ERMS,
  42                          ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
  43                                      "=d" (len)),
  44                          "1" (to), "2" (from), "3" (len)
  45                          : "memory", "rcx", "r8", "r9", "r10", "r11");
  46         return ret;
  47 }
  48
  49 static __always_inline __must_check unsigned long
  50 raw_copy_from_user(void *dst, const void __user *src, unsigned long size)
  51 {
  52         int ret = 0;
  53
  54         if (!__builtin_constant_p(size))
  55                 return copy_user_generic(dst, (__force void *)src, size);
  56         switch (size) {
  57         case 1:
  58                 __uaccess_begin_nospec();
  59                 __get_user_asm_nozero(*(u8 *)dst, (u8 __user *)src,
  60                               ret, "b", "b", "=q", 1);
  61                 __uaccess_end();
  62                 return ret;
  63         case 2:
  64                 __uaccess_begin_nospec();
  65                 __get_user_asm_nozero(*(u16 *)dst, (u16 __user *)src,
  66                               ret, "w", "w", "=r", 2);
  67                 __uaccess_end();
  68                 return ret;
  69         case 4:
  70                 __uaccess_begin_nospec();
  71                 __get_user_asm_nozero(*(u32 *)dst, (u32 __user *)src,
  72                               ret, "l", "k", "=r", 4);
  73                 __uaccess_end();
  74                 return ret;
  75         case 8:
  76                 __uaccess_begin_nospec();
  77                 __get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
  78                               ret, "q", "", "=r", 8);
  79                 __uaccess_end();
  80                 return ret;
  81         case 10:
  82                 __uaccess_begin_nospec();
  83                 __get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
  84                                ret, "q", "", "=r", 10);
  85                 if (likely(!ret))
  86                         __get_user_asm_nozero(*(u16 *)(8 + (char *)dst),
  87                                        (u16 __user *)(8 + (char __user *)src),
  88                                        ret, "w", "w", "=r", 2);
  89                 __uaccess_end();
  90                 return ret;
  91         case 16:
  92                 __uaccess_begin_nospec();
  93                 __get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
  94                                ret, "q", "", "=r", 16);
  95                 if (likely(!ret))
  96                         __get_user_asm_nozero(*(u64 *)(8 + (char *)dst),
  97                                        (u64 __user *)(8 + (char __user *)src),
  98                                        ret, "q", "", "=r", 8);
  99                 __uaccess_end();
 100                 return ret;
 101         default:
 102                 return copy_user_generic(dst, (__force void *)src, size);
 103         }
 104 }
 105
 106 static __always_inline __must_check unsigned long
 107 raw_copy_to_user(void __user *dst, const void *src, unsigned long size)
 108 {
 109         int ret = 0;
 110
 111         if (!__builtin_constant_p(size))
 112                 return copy_user_generic((__force void *)dst, src, size);
 113         switch (size) {
 114         case 1:
 115                 __uaccess_begin();
 116                 __put_user_asm(*(u8 *)src, (u8 __user *)dst,
 117                               ret, "b", "b", "iq", 1);
 118                 __uaccess_end();
 119                 return ret;
 120         case 2:
 121                 __uaccess_begin();
 122                 __put_user_asm(*(u16 *)src, (u16 __user *)dst,
 123                               ret, "w", "w", "ir", 2);
 124                 __uaccess_end();
 125                 return ret;
 126         case 4:
 127                 __uaccess_begin();
 128                 __put_user_asm(*(u32 *)src, (u32 __user *)dst,
 129                               ret, "l", "k", "ir", 4);
 130                 __uaccess_end();
 131                 return ret;
 132         case 8:
 133                 __uaccess_begin();
 134                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 135                               ret, "q", "", "er", 8);
 136                 __uaccess_end();
 137                 return ret;
 138         case 10:
 139                 __uaccess_begin();
 140                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 141                                ret, "q", "", "er", 10);
 142                 if (likely(!ret)) {
 143                         asm("":::"memory");
 144                         __put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
 145                                        ret, "w", "w", "ir", 2);
 146                 }
 147                 __uaccess_end();
 148                 return ret;
 149         case 16:
 150                 __uaccess_begin();
 151                 __put_user_asm(*(u64 *)src, (u64 __user *)dst,
 152                                ret, "q", "", "er", 16);
 153                 if (likely(!ret)) {
 154                         asm("":::"memory");
 155                         __put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
 156                                        ret, "q", "", "er", 8);
 157                 }
 158                 __uaccess_end();
 159                 return ret;
 160         default:
 161                 return copy_user_generic((__force void *)dst, src, size);
 162         }
 163 }
 164
 165 static __always_inline __must_check
 166 unsigned long raw_copy_in_user(void __user *dst, const void __user *src, unsigned long size)
 167 {
 168         return copy_user_generic((__force void *)dst,
 169                                  (__force void *)src, size);
 170 }
 171
 172 extern long __copy_user_nocache(void *dst, const void __user *src,
 173                                 unsigned size, int zerorest);
 174
 175 extern long __copy_user_flushcache(void *dst, const void __user *src, unsigned size);
 176 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 177                            size_t len);
 178
 179 static inline int
 180 __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
 181                                   unsigned size)
 182 {
 183         kasan_check_write(dst, size);
 184         return __copy_user_nocache(dst, src, size, 0);
 185 }
 186
 187 static inline int
 188 __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
 189 {
 190         kasan_check_write(dst, size);
 191         return __copy_user_flushcache(dst, src, size);
 192 }
 193
 194 unsigned long
 195 copy_user_handle_tail(char *to, char *from, unsigned len);
 196
 197 #endif /* _ASM_X86_UACCESS_64_H */