1 #ifndef __i386_UACCESS_H
2 #define __i386_UACCESS_H
5 * User space memory access functions
7 #include <linux/errno.h>
8 #include <linux/thread_info.h>
9 #include <linux/prefetch.h>
10 #include <linux/string.h>
14 unsigned long __must_check __copy_to_user_ll
15 (void __user *to, const void *from, unsigned long n);
16 unsigned long __must_check __copy_from_user_ll
17 (void *to, const void __user *from, unsigned long n);
18 unsigned long __must_check __copy_from_user_ll_nozero
19 (void *to, const void __user *from, unsigned long n);
20 unsigned long __must_check __copy_from_user_ll_nocache
21 (void *to, const void __user *from, unsigned long n);
22 unsigned long __must_check __copy_from_user_ll_nocache_nozero
23 (void *to, const void __user *from, unsigned long n);
26 * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
27 * @to: Destination address, in user space.
28 * @from: Source address, in kernel space.
29 * @n: Number of bytes to copy.
31 * Context: User context only.
33 * Copy data from kernel space to user space. Caller must check
34 * the specified block with access_ok() before calling this function.
35 * The caller should also make sure he pins the user space address
36 * so that the we don't result in page fault and sleep.
38 * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
39 * we return the initial request size (1, 2 or 4), as copy_*_user should do.
40 * If a store crosses a page boundary and gets a fault, the x86 will not write
41 * anything, so this is accurate.
44 static __always_inline unsigned long __must_check
45 __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
47 if (__builtin_constant_p(n)) {
52 __put_user_size(*(u8 *)from, (u8 __user *)to,
56 __put_user_size(*(u16 *)from, (u16 __user *)to,
60 __put_user_size(*(u32 *)from, (u32 __user *)to,
65 return __copy_to_user_ll(to, from, n);
69 * __copy_to_user: - Copy a block of data into user space, with less checking.
70 * @to: Destination address, in user space.
71 * @from: Source address, in kernel space.
72 * @n: Number of bytes to copy.
74 * Context: User context only. This function may sleep.
76 * Copy data from kernel space to user space. Caller must check
77 * the specified block with access_ok() before calling this function.
79 * Returns number of bytes that could not be copied.
80 * On success, this will be zero.
82 static __always_inline unsigned long __must_check
83 __copy_to_user(void __user *to, const void *from, unsigned long n)
87 might_lock_read(¤t->mm->mmap_sem);
88 return __copy_to_user_inatomic(to, from, n);
91 static __always_inline unsigned long
92 __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
94 /* Avoid zeroing the tail if the copy fails..
95 * If 'n' is constant and 1, 2, or 4, we do still zero on a failure,
96 * but as the zeroing behaviour is only significant when n is not
97 * constant, that shouldn't be a problem.
99 if (__builtin_constant_p(n)) {
104 __get_user_size(*(u8 *)to, from, 1, ret, 1);
107 __get_user_size(*(u16 *)to, from, 2, ret, 2);
110 __get_user_size(*(u32 *)to, from, 4, ret, 4);
114 return __copy_from_user_ll_nozero(to, from, n);
118 * __copy_from_user: - Copy a block of data from user space, with less checking.
119 * @to: Destination address, in kernel space.
120 * @from: Source address, in user space.
121 * @n: Number of bytes to copy.
123 * Context: User context only. This function may sleep.
125 * Copy data from user space to kernel space. Caller must check
126 * the specified block with access_ok() before calling this function.
128 * Returns number of bytes that could not be copied.
129 * On success, this will be zero.
131 * If some data could not be copied, this function will pad the copied
132 * data to the requested size using zero bytes.
134 * An alternate version - __copy_from_user_inatomic() - may be called from
135 * atomic context and will fail rather than sleep. In this case the
136 * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h
137 * for explanation of why this is needed.
139 static __always_inline unsigned long
140 __copy_from_user(void *to, const void __user *from, unsigned long n)
144 might_lock_read(¤t->mm->mmap_sem);
145 if (__builtin_constant_p(n)) {
150 __get_user_size(*(u8 *)to, from, 1, ret, 1);
153 __get_user_size(*(u16 *)to, from, 2, ret, 2);
156 __get_user_size(*(u32 *)to, from, 4, ret, 4);
160 return __copy_from_user_ll(to, from, n);
163 static __always_inline unsigned long __copy_from_user_nocache(void *to,
164 const void __user *from, unsigned long n)
168 might_lock_read(¤t->mm->mmap_sem);
169 if (__builtin_constant_p(n)) {
174 __get_user_size(*(u8 *)to, from, 1, ret, 1);
177 __get_user_size(*(u16 *)to, from, 2, ret, 2);
180 __get_user_size(*(u32 *)to, from, 4, ret, 4);
184 return __copy_from_user_ll_nocache(to, from, n);
187 static __always_inline unsigned long
188 __copy_from_user_inatomic_nocache(void *to, const void __user *from,
191 return __copy_from_user_ll_nocache_nozero(to, from, n);
194 unsigned long __must_check copy_to_user(void __user *to,
195 const void *from, unsigned long n);
196 unsigned long __must_check copy_from_user(void *to,
197 const void __user *from,
199 long __must_check strncpy_from_user(char *dst, const char __user *src,
201 long __must_check __strncpy_from_user(char *dst,
202 const char __user *src, long count);
205 * strlen_user: - Get the size of a string in user space.
206 * @str: The string to measure.
208 * Context: User context only. This function may sleep.
210 * Get the size of a NUL-terminated string in user space.
212 * Returns the size of the string INCLUDING the terminating NUL.
213 * On exception, returns 0.
215 * If there is a limit on the length of a valid string, you may wish to
216 * consider using strnlen_user() instead.
218 #define strlen_user(str) strnlen_user(str, LONG_MAX)
220 long strnlen_user(const char __user *str, long n);
221 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
222 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
224 #endif /* __i386_UACCESS_H */