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| Rev | Author | Line No. | Line |
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| 7143 | serge | 1 | #ifndef _ASM_X86_UACCESS_32_H |
| 2 | #define _ASM_X86_UACCESS_32_H |
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| 3 | |||
| 4 | /* |
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| 5 | * User space memory access functions |
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| 6 | */ |
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| 7 | #include |
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| 8 | #include |
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| 9 | #include |
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| 10 | #include |
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| 11 | #include |
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| 12 | |||
| 13 | unsigned long __must_check __copy_to_user_ll |
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| 14 | (void __user *to, const void *from, unsigned long n); |
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| 15 | unsigned long __must_check __copy_from_user_ll |
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| 16 | (void *to, const void __user *from, unsigned long n); |
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| 17 | unsigned long __must_check __copy_from_user_ll_nozero |
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| 18 | (void *to, const void __user *from, unsigned long n); |
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| 19 | unsigned long __must_check __copy_from_user_ll_nocache |
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| 20 | (void *to, const void __user *from, unsigned long n); |
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| 21 | unsigned long __must_check __copy_from_user_ll_nocache_nozero |
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| 22 | (void *to, const void __user *from, unsigned long n); |
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| 23 | |||
| 24 | /** |
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| 25 | * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. |
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| 26 | * @to: Destination address, in user space. |
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| 27 | * @from: Source address, in kernel space. |
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| 28 | * @n: Number of bytes to copy. |
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| 29 | * |
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| 30 | * Context: User context only. |
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| 31 | * |
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| 32 | * Copy data from kernel space to user space. Caller must check |
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| 33 | * the specified block with access_ok() before calling this function. |
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| 34 | * The caller should also make sure he pins the user space address |
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| 35 | * so that we don't result in page fault and sleep. |
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| 36 | * |
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| 37 | * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault |
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| 38 | * we return the initial request size (1, 2 or 4), as copy_*_user should do. |
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| 39 | * If a store crosses a page boundary and gets a fault, the x86 will not write |
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| 40 | * anything, so this is accurate. |
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| 41 | */ |
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| 42 | |||
| 43 | static __always_inline unsigned long __must_check |
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| 44 | __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) |
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| 45 | { |
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| 46 | if (__builtin_constant_p(n)) { |
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| 47 | switch(n) { |
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| 48 | case 1: |
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| 49 | *(u8 __force *)to = *(u8 *)from; |
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| 50 | return 0; |
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| 51 | case 2: |
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| 52 | *(u16 __force *)to = *(u16 *)from; |
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| 53 | return 0; |
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| 54 | case 4: |
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| 55 | *(u32 __force *)to = *(u32 *)from; |
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| 56 | return 0; |
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| 57 | |||
| 58 | case 8: |
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| 59 | *(u64 __force *)to = *(u64 *)from; |
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| 60 | return 0; |
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| 61 | |||
| 62 | default: |
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| 63 | break; |
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| 64 | } |
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| 65 | } |
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| 66 | |||
| 67 | __builtin_memcpy((void __force *)to, from, n); |
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| 68 | return 0; |
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| 69 | } |
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| 70 | |||
| 71 | /** |
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| 72 | * __copy_to_user: - Copy a block of data into user space, with less checking. |
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| 73 | * @to: Destination address, in user space. |
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| 74 | * @from: Source address, in kernel space. |
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| 75 | * @n: Number of bytes to copy. |
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| 76 | * |
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| 77 | * Context: User context only. This function may sleep if pagefaults are |
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| 78 | * enabled. |
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| 79 | * |
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| 80 | * Copy data from kernel space to user space. Caller must check |
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| 81 | * the specified block with access_ok() before calling this function. |
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| 82 | * |
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| 83 | * Returns number of bytes that could not be copied. |
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| 84 | * On success, this will be zero. |
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| 85 | */ |
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| 86 | static __always_inline unsigned long __must_check |
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| 87 | __copy_to_user(void __user *to, const void *from, unsigned long n) |
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| 88 | { |
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| 89 | might_fault(); |
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| 90 | return __copy_to_user_inatomic(to, from, n); |
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| 91 | } |
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| 92 | |||
| 93 | static __always_inline unsigned long |
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| 94 | __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) |
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| 95 | { |
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| 96 | /* Avoid zeroing the tail if the copy fails.. |
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| 97 | * If 'n' is constant and 1, 2, or 4, we do still zero on a failure, |
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| 98 | * but as the zeroing behaviour is only significant when n is not |
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| 99 | * constant, that shouldn't be a problem. |
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| 100 | */ |
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| 101 | if (__builtin_constant_p(n)) { |
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| 102 | switch(n) { |
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| 103 | case 1: |
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| 104 | *(u8 *)to = *(u8 __force *)from; |
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| 105 | return 0; |
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| 106 | case 2: |
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| 107 | *(u16 *)to = *(u16 __force *)from; |
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| 108 | return 0; |
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| 109 | case 4: |
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| 110 | *(u32 *)to = *(u32 __force *)from; |
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| 111 | return 0; |
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| 112 | |||
| 113 | case 8: |
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| 114 | *(u64 *)to = *(u64 __force *)from; |
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| 115 | return 0; |
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| 116 | |||
| 117 | default: |
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| 118 | break; |
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| 119 | } |
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| 120 | } |
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| 121 | |||
| 122 | __builtin_memcpy(to, (const void __force *)from, n); |
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| 123 | return 0; |
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| 124 | } |
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| 125 | |||
| 126 | /** |
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| 127 | * __copy_from_user: - Copy a block of data from user space, with less checking. |
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| 128 | * @to: Destination address, in kernel space. |
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| 129 | * @from: Source address, in user space. |
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| 130 | * @n: Number of bytes to copy. |
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| 131 | * |
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| 132 | * Context: User context only. This function may sleep if pagefaults are |
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| 133 | * enabled. |
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| 134 | * |
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| 135 | * Copy data from user space to kernel space. Caller must check |
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| 136 | * the specified block with access_ok() before calling this function. |
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| 137 | * |
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| 138 | * Returns number of bytes that could not be copied. |
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| 139 | * On success, this will be zero. |
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| 140 | * |
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| 141 | * If some data could not be copied, this function will pad the copied |
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| 142 | * data to the requested size using zero bytes. |
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| 143 | * |
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| 144 | * An alternate version - __copy_from_user_inatomic() - may be called from |
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| 145 | * atomic context and will fail rather than sleep. In this case the |
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| 146 | * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h |
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| 147 | * for explanation of why this is needed. |
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| 148 | */ |
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| 149 | static __always_inline unsigned long |
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| 150 | __copy_from_user(void *to, const void __user *from, unsigned long n) |
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| 151 | { |
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| 152 | might_fault(); |
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| 153 | if (__builtin_constant_p(n)) { |
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| 154 | switch(n) { |
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| 155 | case 1: |
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| 156 | *(u8 *)to = *(u8 __force *)from; |
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| 157 | return 0; |
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| 158 | case 2: |
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| 159 | *(u16 *)to = *(u16 __force *)from; |
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| 160 | return 0; |
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| 161 | case 4: |
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| 162 | *(u32 *)to = *(u32 __force *)from; |
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| 163 | return 0; |
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| 164 | |||
| 165 | case 8: |
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| 166 | *(u64 *)to = *(u64 __force *)from; |
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| 167 | return 0; |
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| 168 | |||
| 169 | default: |
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| 170 | break; |
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| 171 | } |
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| 172 | } |
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| 173 | |||
| 174 | __builtin_memcpy(to, (const void __force *)from, n); |
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| 175 | return 0; |
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| 176 | } |
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| 177 | |||
| 178 | static __always_inline unsigned long __copy_from_user_nocache(void *to, |
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| 179 | const void __user *from, unsigned long n) |
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| 180 | { |
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| 181 | might_fault(); |
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| 182 | if (__builtin_constant_p(n)) { |
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| 183 | switch(n) { |
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| 184 | case 1: |
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| 185 | *(u8 *)to = *(u8 __force *)from; |
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| 186 | return 0; |
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| 187 | case 2: |
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| 188 | *(u16 *)to = *(u16 __force *)from; |
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| 189 | return 0; |
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| 190 | case 4: |
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| 191 | *(u32 *)to = *(u32 __force *)from; |
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| 192 | return 0; |
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| 193 | default: |
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| 194 | break; |
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| 195 | } |
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| 196 | } |
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| 197 | __builtin_memcpy(to, (const void __force *)from, n); |
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| 198 | return 0; |
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| 199 | } |
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| 200 | |||
| 201 | static __always_inline unsigned long |
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| 202 | __copy_from_user_inatomic_nocache(void *to, const void __user *from, |
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| 203 | unsigned long n) |
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| 204 | { |
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| 205 | return __copy_from_user_inatomic(to, from, n); |
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| 206 | } |
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| 207 | |||
| 208 | #endif /* _ASM_X86_UACCESS_32_H */ |