1 #ifndef _ASM_X86_UACCESS_32_H 2 #define _ASM_X86_UACCESS_32_H 3 4 /* 5 * User space memory access functions 6 */ 7 #include <linux/errno.h> 8 #include <linux/thread_info.h> 9 #include <linux/string.h> 10 #include <asm/asm.h> 11 #include <asm/page.h> 12 13 unsigned long __must_check __copy_to_user_ll 14 (void __user *to, const void *from, unsigned long n); 15 unsigned long __must_check __copy_from_user_ll 16 (void *to, const void __user *from, unsigned long n); 17 unsigned long __must_check __copy_from_user_ll_nozero 18 (void *to, const void __user *from, unsigned long n); 19 unsigned long __must_check __copy_from_user_ll_nocache 20 (void *to, const void __user *from, unsigned long n); 21 unsigned long __must_check __copy_from_user_ll_nocache_nozero 22 (void *to, const void __user *from, unsigned long n); 23 24 /** 25 * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. 26 * @to: Destination address, in user space. 27 * @from: Source address, in kernel space. 28 * @n: Number of bytes to copy. 29 * 30 * Context: User context only. 31 * 32 * Copy data from kernel space to user space. Caller must check 33 * the specified block with access_ok() before calling this function. 34 * The caller should also make sure he pins the user space address 35 * so that we don't result in page fault and sleep. 36 */ 37 static __always_inline unsigned long __must_check 38 __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) 39 { 40 return __copy_to_user_ll(to, from, n); 41 } 42 43 /** 44 * __copy_to_user: - Copy a block of data into user space, with less checking. 45 * @to: Destination address, in user space. 46 * @from: Source address, in kernel space. 47 * @n: Number of bytes to copy. 48 * 49 * Context: User context only. This function may sleep if pagefaults are 50 * enabled. 51 * 52 * Copy data from kernel space to user space. Caller must check 53 * the specified block with access_ok() before calling this function. 54 * 55 * Returns number of bytes that could not be copied. 56 * On success, this will be zero. 57 */ 58 static __always_inline unsigned long __must_check 59 __copy_to_user(void __user *to, const void *from, unsigned long n) 60 { 61 might_fault(); 62 return __copy_to_user_inatomic(to, from, n); 63 } 64 65 static __always_inline unsigned long 66 __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) 67 { 68 return __copy_from_user_ll_nozero(to, from, n); 69 } 70 71 /** 72 * __copy_from_user: - Copy a block of data from user space, with less checking. 73 * @to: Destination address, in kernel space. 74 * @from: Source address, in user space. 75 * @n: Number of bytes to copy. 76 * 77 * Context: User context only. This function may sleep if pagefaults are 78 * enabled. 79 * 80 * Copy data from user space to kernel space. Caller must check 81 * the specified block with access_ok() before calling this function. 82 * 83 * Returns number of bytes that could not be copied. 84 * On success, this will be zero. 85 * 86 * If some data could not be copied, this function will pad the copied 87 * data to the requested size using zero bytes. 88 * 89 * An alternate version - __copy_from_user_inatomic() - may be called from 90 * atomic context and will fail rather than sleep. In this case the 91 * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h 92 * for explanation of why this is needed. 93 */ 94 static __always_inline unsigned long 95 __copy_from_user(void *to, const void __user *from, unsigned long n) 96 { 97 might_fault(); 98 if (__builtin_constant_p(n)) { 99 unsigned long ret; 100 101 switch (n) { 102 case 1: 103 __uaccess_begin(); 104 __get_user_size(*(u8 *)to, from, 1, ret, 1); 105 __uaccess_end(); 106 return ret; 107 case 2: 108 __uaccess_begin(); 109 __get_user_size(*(u16 *)to, from, 2, ret, 2); 110 __uaccess_end(); 111 return ret; 112 case 4: 113 __uaccess_begin(); 114 __get_user_size(*(u32 *)to, from, 4, ret, 4); 115 __uaccess_end(); 116 return ret; 117 } 118 } 119 return __copy_from_user_ll(to, from, n); 120 } 121 122 static __always_inline unsigned long __copy_from_user_nocache(void *to, 123 const void __user *from, unsigned long n) 124 { 125 might_fault(); 126 if (__builtin_constant_p(n)) { 127 unsigned long ret; 128 129 switch (n) { 130 case 1: 131 __uaccess_begin(); 132 __get_user_size(*(u8 *)to, from, 1, ret, 1); 133 __uaccess_end(); 134 return ret; 135 case 2: 136 __uaccess_begin(); 137 __get_user_size(*(u16 *)to, from, 2, ret, 2); 138 __uaccess_end(); 139 return ret; 140 case 4: 141 __uaccess_begin(); 142 __get_user_size(*(u32 *)to, from, 4, ret, 4); 143 __uaccess_end(); 144 return ret; 145 } 146 } 147 return __copy_from_user_ll_nocache(to, from, n); 148 } 149 150 static __always_inline unsigned long 151 __copy_from_user_inatomic_nocache(void *to, const void __user *from, 152 unsigned long n) 153 { 154 return __copy_from_user_ll_nocache_nozero(to, from, n); 155 } 156 157 #endif /* _ASM_X86_UACCESS_32_H */ 158