uaccess.h (762f99f4f3cb41a775b5157dd761217beba65873) uaccess.h (12700c17fc286149324f92d6d380bc48e43f253d)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
5 * vineetg: June 2010
6 * -__clear_user( ) called multiple times during elf load was byte loop
7 * converted to do as much word clear as possible.
8 *

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18 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
19 */
20
21#ifndef _ASM_ARC_UACCESS_H
22#define _ASM_ARC_UACCESS_H
23
24#include <linux/string.h> /* for generic string functions */
25
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
5 * vineetg: June 2010
6 * -__clear_user( ) called multiple times during elf load was byte loop
7 * converted to do as much word clear as possible.
8 *

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18 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
19 */
20
21#ifndef _ASM_ARC_UACCESS_H
22#define _ASM_ARC_UACCESS_H
23
24#include <linux/string.h> /* for generic string functions */
25
26
27#define __kernel_ok (uaccess_kernel())
28
29/*
30 * Algorithmically, for __user_ok() we want do:
31 * (start < TASK_SIZE) && (start+len < TASK_SIZE)
32 * where TASK_SIZE could either be retrieved from thread_info->addr_limit or
33 * emitted directly in code.
34 *
35 * This can however be rewritten as follows:
36 * (len <= TASK_SIZE) && (start+len < TASK_SIZE)
37 *
38 * Because it essentially checks if buffer end is within limit and @len is
39 * non-ngeative, which implies that buffer start will be within limit too.
40 *
41 * The reason for rewriting being, for majority of cases, @len is generally
42 * compile time constant, causing first sub-expression to be compile time
43 * subsumed.
44 *
45 * The second part would generate weird large LIMMs e.g. (0x6000_0000 - 0x10),
46 * so we check for TASK_SIZE using get_fs() since the addr_limit load from mem
47 * would already have been done at this call site for __kernel_ok()
48 *
49 */
50#define __user_ok(addr, sz) (((sz) <= TASK_SIZE) && \
51 ((addr) <= (get_fs() - (sz))))
52#define __access_ok(addr, sz) (unlikely(__kernel_ok) || \
53 likely(__user_ok((addr), (sz))))
54
55/*********** Single byte/hword/word copies ******************/
56
57#define __get_user_fn(sz, u, k) \
58({ \
59 long __ret = 0; /* success by default */ \
60 switch (sz) { \
61 case 1: __arc_get_user_one(*(k), u, "ldb", __ret); break; \
62 case 2: __arc_get_user_one(*(k), u, "ldw", __ret); break; \

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27
28#define __get_user_fn(sz, u, k) \
29({ \
30 long __ret = 0; /* success by default */ \
31 switch (sz) { \
32 case 1: __arc_get_user_one(*(k), u, "ldb", __ret); break; \
33 case 2: __arc_get_user_one(*(k), u, "ldw", __ret); break; \

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