arch/x86/include/asm/uaccess_32.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_UACCESS_32_H
   3 #define _ASM_X86_UACCESS_32_H
   4
   5 /*
   6  * User space memory access functions
   7  */
   8 #include <linux/string.h>
   9 #include <asm/asm.h>
  10 #include <asm/page.h>
  11
  12 unsigned long __must_check __copy_user_ll
  13                 (void *to, const void *from, unsigned long n);
  14 unsigned long __must_check __copy_from_user_ll_nocache_nozero
  15                 (void *to, const void __user *from, unsigned long n);
  16
  17 static __always_inline unsigned long __must_check
  18 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
  19 {
  20         return __copy_user_ll((__force void *)to, from, n);
  21 }
  22
  23 static __always_inline unsigned long
  24 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
  25 {
  26         if (__builtin_constant_p(n)) {
  27                 unsigned long ret;
  28
  29                 switch (n) {
  30                 case 1:
  31                         ret = 0;
  32                         __uaccess_begin_nospec();
  33                         __get_user_asm_nozero(*(u8 *)to, from, ret,
  34                                               "b", "b", "=q", 1);
  35                         __uaccess_end();
  36                         return ret;
  37                 case 2:
  38                         ret = 0;
  39                         __uaccess_begin_nospec();
  40                         __get_user_asm_nozero(*(u16 *)to, from, ret,
  41                                               "w", "w", "=r", 2);
  42                         __uaccess_end();
  43                         return ret;
  44                 case 4:
  45                         ret = 0;
  46                         __uaccess_begin_nospec();
  47                         __get_user_asm_nozero(*(u32 *)to, from, ret,
  48                                               "l", "k", "=r", 4);
  49                         __uaccess_end();
  50                         return ret;
  51                 }
  52         }
  53         return __copy_user_ll(to, (__force const void *)from, n);
  54 }
  55
  56 static __always_inline unsigned long
  57 __copy_from_user_inatomic_nocache(void *to, const void __user *from,
  58                                   unsigned long n)
  59 {
  60        return __copy_from_user_ll_nocache_nozero(to, from, n);
  61 }
  62
  63 #endif /* _ASM_X86_UACCESS_32_H */