218 lines
6.5 KiB
C
218 lines
6.5 KiB
C
#ifndef _ASM_X86_UACCESS_32_H
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#define _ASM_X86_UACCESS_32_H
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/*
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* User space memory access functions
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*/
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#include <linux/errno.h>
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#include <linux/thread_info.h>
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#include <linux/prefetch.h>
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#include <linux/string.h>
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#include <asm/asm.h>
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#include <asm/page.h>
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unsigned long __must_check __copy_to_user_ll
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(void __user *to, const void *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll
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(void *to, const void __user *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll_nozero
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(void *to, const void __user *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll_nocache
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(void *to, const void __user *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll_nocache_nozero
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(void *to, const void __user *from, unsigned long n);
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/**
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* __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only.
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*
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* Copy data from kernel space to user space. Caller must check
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* the specified block with access_ok() before calling this function.
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* The caller should also make sure he pins the user space address
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* so that the we don't result in page fault and sleep.
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*
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* Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
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* we return the initial request size (1, 2 or 4), as copy_*_user should do.
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* If a store crosses a page boundary and gets a fault, the x86 will not write
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* anything, so this is accurate.
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*/
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static __always_inline unsigned long __must_check
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__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
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{
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__put_user_size(*(u8 *)from, (u8 __user *)to,
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1, ret, 1);
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return ret;
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case 2:
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__put_user_size(*(u16 *)from, (u16 __user *)to,
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2, ret, 2);
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return ret;
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case 4:
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__put_user_size(*(u32 *)from, (u32 __user *)to,
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4, ret, 4);
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return ret;
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}
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}
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return __copy_to_user_ll(to, from, n);
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}
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/**
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* __copy_to_user: - Copy a block of data into user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only. This function may sleep.
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*
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* Copy data from kernel space to user space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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*/
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static __always_inline unsigned long __must_check
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__copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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might_fault();
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return __copy_to_user_inatomic(to, from, n);
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}
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static __always_inline unsigned long
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__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
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{
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/* Avoid zeroing the tail if the copy fails..
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* If 'n' is constant and 1, 2, or 4, we do still zero on a failure,
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* but as the zeroing behaviour is only significant when n is not
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* constant, that shouldn't be a problem.
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*/
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__get_user_size(*(u8 *)to, from, 1, ret, 1);
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return ret;
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case 2:
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__get_user_size(*(u16 *)to, from, 2, ret, 2);
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return ret;
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case 4:
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__get_user_size(*(u32 *)to, from, 4, ret, 4);
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return ret;
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}
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}
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return __copy_from_user_ll_nozero(to, from, n);
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}
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/**
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* __copy_from_user: - Copy a block of data from user space, with less checking.
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* @to: Destination address, in kernel space.
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* @from: Source address, in user space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only. This function may sleep.
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*
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* Copy data from user space to kernel space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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*
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* If some data could not be copied, this function will pad the copied
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* data to the requested size using zero bytes.
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*
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* An alternate version - __copy_from_user_inatomic() - may be called from
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* atomic context and will fail rather than sleep. In this case the
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* uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h
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* for explanation of why this is needed.
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*/
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static __always_inline unsigned long
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__copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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might_fault();
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__get_user_size(*(u8 *)to, from, 1, ret, 1);
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return ret;
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case 2:
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__get_user_size(*(u16 *)to, from, 2, ret, 2);
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return ret;
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case 4:
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__get_user_size(*(u32 *)to, from, 4, ret, 4);
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return ret;
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}
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}
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return __copy_from_user_ll(to, from, n);
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}
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static __always_inline unsigned long __copy_from_user_nocache(void *to,
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const void __user *from, unsigned long n)
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{
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might_fault();
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__get_user_size(*(u8 *)to, from, 1, ret, 1);
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return ret;
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case 2:
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__get_user_size(*(u16 *)to, from, 2, ret, 2);
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return ret;
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case 4:
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__get_user_size(*(u32 *)to, from, 4, ret, 4);
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return ret;
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}
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}
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return __copy_from_user_ll_nocache(to, from, n);
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}
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static __always_inline unsigned long
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__copy_from_user_inatomic_nocache(void *to, const void __user *from,
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unsigned long n)
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{
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return __copy_from_user_ll_nocache_nozero(to, from, n);
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}
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unsigned long __must_check copy_to_user(void __user *to,
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const void *from, unsigned long n);
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unsigned long __must_check copy_from_user(void *to,
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const void __user *from,
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unsigned long n);
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long __must_check strncpy_from_user(char *dst, const char __user *src,
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long count);
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long __must_check __strncpy_from_user(char *dst,
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const char __user *src, long count);
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/**
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* strlen_user: - Get the size of a string in user space.
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* @str: The string to measure.
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*
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* Context: User context only. This function may sleep.
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*
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* Get the size of a NUL-terminated string in user space.
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*
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* Returns the size of the string INCLUDING the terminating NUL.
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* On exception, returns 0.
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*
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* If there is a limit on the length of a valid string, you may wish to
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* consider using strnlen_user() instead.
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*/
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#define strlen_user(str) strnlen_user(str, LONG_MAX)
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long strnlen_user(const char __user *str, long n);
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unsigned long __must_check clear_user(void __user *mem, unsigned long len);
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unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
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#endif /* _ASM_X86_UACCESS_32_H */
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