1/*
  2 * User memory access support for Hexagon
  3 *
  4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License version 2 and
  8 * only version 2 as published by the Free Software Foundation.
  9 *
 10 * This program is distributed in the hope that it will be useful,
 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13 * GNU General Public License for more details.
 14 *
 15 * You should have received a copy of the GNU General Public License
 16 * along with this program; if not, write to the Free Software
 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 18 * 02110-1301, USA.
 19 */
 20
 21#ifndef _ASM_UACCESS_H
 22#define _ASM_UACCESS_H
 23/*
 24 * User space memory access functions
 25 */
 26#include <linux/mm.h>
 27#include <asm/segment.h>
 28#include <asm/sections.h>
 29
 30/*
 31 * access_ok: - Checks if a user space pointer is valid
 32 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
 33 *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
 34 *        to write to a block, it is always safe to read from it.
 35 * @addr: User space pointer to start of block to check
 36 * @size: Size of block to check
 37 *
 38 * Context: User context only. This function may sleep if pagefaults are
 39 *          enabled.
 40 *
 41 * Checks if a pointer to a block of memory in user space is valid.
 42 *
 43 * Returns true (nonzero) if the memory block *may* be valid, false (zero)
 44 * if it is definitely invalid.
 45 *
 46 * User address space in Hexagon, like x86, goes to 0xbfffffff, so the
 47 * simple MSB-based tests used by MIPS won't work.  Some further
 48 * optimization is probably possible here, but for now, keep it
 49 * reasonably simple and not *too* slow.  After all, we've got the
 50 * MMU for backup.
 51 */
 52
 53#define __access_ok(addr, size) \
 54	((get_fs().seg == KERNEL_DS.seg) || \
 55	(((unsigned long)addr < get_fs().seg) && \
 56	  (unsigned long)size < (get_fs().seg - (unsigned long)addr)))
 57
 58/*
 59 * When a kernel-mode page fault is taken, the faulting instruction
 60 * address is checked against a table of exception_table_entries.
 61 * Each entry is a tuple of the address of an instruction that may
 62 * be authorized to fault, and the address at which execution should
 63 * be resumed instead of the faulting instruction, so as to effect
 64 * a workaround.
 65 */
 66
 67/*  Assembly somewhat optimized copy routines  */
 68unsigned long raw_copy_from_user(void *to, const void __user *from,
 69				     unsigned long n);
 70unsigned long raw_copy_to_user(void __user *to, const void *from,
 71				   unsigned long n);
 72#define INLINE_COPY_FROM_USER
 73#define INLINE_COPY_TO_USER
 74
 75__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count);
 76#define __clear_user(a, s) __clear_user_hexagon((a), (s))
 77
 78#define __strncpy_from_user(dst, src, n) hexagon_strncpy_from_user(dst, src, n)
 79
 80/*  get around the ifndef in asm-generic/uaccess.h  */
 81#define __strnlen_user __strnlen_user
 82
 83extern long __strnlen_user(const char __user *src, long n);
 84
 85static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
 86					     long n);
 87
 88#include <asm-generic/uaccess.h>
 89
 90/*  Todo:  an actual accelerated version of this.  */
 91static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
 92					     long n)
 93{
 94	long res = __strnlen_user(src, n);
 95
 96	if (unlikely(!res))
 97		return -EFAULT;
 98
 99	if (res > n) {
100		long left = raw_copy_from_user(dst, src, n);
101		if (unlikely(left))
102			memset(dst + (n - left), 0, left);
103		return n;
104	} else {
105		long left = raw_copy_from_user(dst, src, res);
106		if (unlikely(left))
107			memset(dst + (res - left), 0, left);
108		return res-1;
109	}
110}
111
112#endif

 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 * When a kernel-mode page fault is taken, the faulting instruction
17 * address is checked against a table of exception_table_entries.
18 * Each entry is a tuple of the address of an instruction that may
19 * be authorized to fault, and the address at which execution should
20 * be resumed instead of the faulting instruction, so as to effect
21 * a workaround.
22 */
23
24/*  Assembly somewhat optimized copy routines  */
25unsigned long raw_copy_from_user(void *to, const void __user *from,
26				     unsigned long n);
27unsigned long raw_copy_to_user(void __user *to, const void *from,
28				   unsigned long n);
29#define INLINE_COPY_FROM_USER
30#define INLINE_COPY_TO_USER
31
32__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count);
33#define __clear_user(a, s) __clear_user_hexagon((a), (s))
34
 
 
 
 
 
 
 
 
 
 
35#include <asm-generic/uaccess.h>
36
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
37
38#endif