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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2013 ARM Ltd.
4 */
5#ifndef __ASM_WORD_AT_A_TIME_H
6#define __ASM_WORD_AT_A_TIME_H
7
8#include <linux/uaccess.h>
9
10#ifndef __AARCH64EB__
11
12#include <linux/bitops.h>
13#include <linux/wordpart.h>
14
15struct word_at_a_time {
16 const unsigned long one_bits, high_bits;
17};
18
19#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
20
21static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
22 const struct word_at_a_time *c)
23{
24 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
25 *bits = mask;
26 return mask;
27}
28
29#define prep_zero_mask(a, bits, c) (bits)
30
31static inline unsigned long create_zero_mask(unsigned long bits)
32{
33 bits = (bits - 1) & ~bits;
34 return bits >> 7;
35}
36
37static inline unsigned long find_zero(unsigned long mask)
38{
39 return fls64(mask) >> 3;
40}
41
42#define zero_bytemask(mask) (mask)
43
44#else /* __AARCH64EB__ */
45#include <asm-generic/word-at-a-time.h>
46#endif
47
48/*
49 * Load an unaligned word from kernel space.
50 *
51 * In the (very unlikely) case of the word being a page-crosser
52 * and the next page not being mapped, take the exception and
53 * return zeroes in the non-existing part.
54 */
55static inline unsigned long load_unaligned_zeropad(const void *addr)
56{
57 unsigned long ret;
58
59 __mte_enable_tco_async();
60
61 /* Load word from unaligned pointer addr */
62 asm(
63 "1: ldr %0, %2\n"
64 "2:\n"
65 _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1)
66 : "=&r" (ret)
67 : "r" (addr), "Q" (*(unsigned long *)addr));
68
69 __mte_disable_tco_async();
70
71 return ret;
72}
73
74#endif /* __ASM_WORD_AT_A_TIME_H */