linux/arch/um/include/asm/uaccess.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/* 
   3 * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
   4 * Copyright (C) 2015 Richard Weinberger (richard@nod.at)
   5 */
   6
   7#ifndef __UM_UACCESS_H
   8#define __UM_UACCESS_H
   9
  10#include <asm/elf.h>
  11
  12#define __under_task_size(addr, size) \
  13        (((unsigned long) (addr) < TASK_SIZE) && \
  14         (((unsigned long) (addr) + (size)) < TASK_SIZE))
  15
  16#define __access_ok_vsyscall(addr, size) \
  17          (((unsigned long) (addr) >= FIXADDR_USER_START) && \
  18          ((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \
  19          ((unsigned long) (addr) + (size) >= (unsigned long)(addr)))
  20
  21#define __addr_range_nowrap(addr, size) \
  22        ((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
  23
  24extern unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n);
  25extern unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n);
  26extern long __strncpy_from_user(char *dst, const char __user *src, long count);
  27extern long __strnlen_user(const void __user *str, long len);
  28extern unsigned long __clear_user(void __user *mem, unsigned long len);
  29static inline int __access_ok(unsigned long addr, unsigned long size);
  30
  31/* Teach asm-generic/uaccess.h that we have C functions for these. */
  32#define __access_ok __access_ok
  33#define __clear_user __clear_user
  34#define __strnlen_user __strnlen_user
  35#define __strncpy_from_user __strncpy_from_user
  36#define INLINE_COPY_FROM_USER
  37#define INLINE_COPY_TO_USER
  38
  39#include <asm-generic/uaccess.h>
  40
  41static inline int __access_ok(unsigned long addr, unsigned long size)
  42{
  43        return __addr_range_nowrap(addr, size) &&
  44                (__under_task_size(addr, size) ||
  45                __access_ok_vsyscall(addr, size) ||
  46                uaccess_kernel());
  47}
  48
  49#endif
  50