LXR linux/arch/hexagon/include/asm/uaccess.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * User memory access support for Hexagon
   4 *
   5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   6 */
   7
   8#ifndef _ASM_UACCESS_H
   9#define _ASM_UACCESS_H
  10/*
  11 * User space memory access functions
  12 */
  13#include <asm/sections.h>
  14
  15/*
  16 * access_ok: - Checks if a user space pointer is valid
  17 * @addr: User space pointer to start of block to check
  18 * @size: Size of block to check
  19 *
  20 * Context: User context only. This function may sleep if pagefaults are
  21 *          enabled.
  22 *
  23 * Checks if a pointer to a block of memory in user space is valid.
  24 *
  25 * Returns true (nonzero) if the memory block *may* be valid, false (zero)
  26 * if it is definitely invalid.
  27 *
  28 * User address space in Hexagon, like x86, goes to 0xbfffffff, so the
  29 * simple MSB-based tests used by MIPS won't work.  Some further
  30 * optimization is probably possible here, but for now, keep it
  31 * reasonably simple and not *too* slow.  After all, we've got the
  32 * MMU for backup.
  33 */
  34
  35#define __access_ok(addr, size) \
  36        ((get_fs().seg == KERNEL_DS.seg) || \
  37        (((unsigned long)addr < get_fs().seg) && \
  38          (unsigned long)size < (get_fs().seg - (unsigned long)addr)))
  39
  40/*
  41 * When a kernel-mode page fault is taken, the faulting instruction
  42 * address is checked against a table of exception_table_entries.
  43 * Each entry is a tuple of the address of an instruction that may
  44 * be authorized to fault, and the address at which execution should
  45 * be resumed instead of the faulting instruction, so as to effect
  46 * a workaround.
  47 */
  48
  49/*  Assembly somewhat optimized copy routines  */
  50unsigned long raw_copy_from_user(void *to, const void __user *from,
  51                                     unsigned long n);
  52unsigned long raw_copy_to_user(void __user *to, const void *from,
  53                                   unsigned long n);
  54#define INLINE_COPY_FROM_USER
  55#define INLINE_COPY_TO_USER
  56
  57__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count);
  58#define __clear_user(a, s) __clear_user_hexagon((a), (s))
  59
  60#include <asm-generic/uaccess.h>
  61
  62
  63#endif
  64