51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
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#ifndef UACCESS_H
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#define UACCESS_H
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extern void *__user_addr_min, *__user_addr_max;
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#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
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static inline void __chk_user_ptr(const volatile void *p, size_t size)
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{
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assert(p >= __user_addr_min && p + size <= __user_addr_max);
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}
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#define put_user(x, ptr) \
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({ \
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typeof(ptr) __pu_ptr = (ptr); \
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__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr)); \
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ACCESS_ONCE(*(__pu_ptr)) = x; \
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0; \
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})
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#define get_user(x, ptr) \
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({ \
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typeof(ptr) __pu_ptr = (ptr); \
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__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr)); \
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x = ACCESS_ONCE(*(__pu_ptr)); \
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0; \
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})
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static void volatile_memcpy(volatile char *to, const volatile char *from,
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unsigned long n)
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{
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while (n--)
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*(to++) = *(from++);
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}
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static inline int copy_from_user(void *to, const void __user volatile *from,
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unsigned long n)
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{
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__chk_user_ptr(from, n);
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volatile_memcpy(to, from, n);
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return 0;
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}
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static inline int copy_to_user(void __user volatile *to, const void *from,
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unsigned long n)
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{
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__chk_user_ptr(to, n);
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volatile_memcpy(to, from, n);
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return 0;
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}
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#endif /* UACCESS_H */
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