1/*
2 * Copyright (C) 2013 ARM Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
15 */
16#ifndef __ASM_WORD_AT_A_TIME_H
17#define __ASM_WORD_AT_A_TIME_H
18
19#ifndef __AARCH64EB__
20
21#include <linux/kernel.h>
22
23struct word_at_a_time {
24	const unsigned long one_bits, high_bits;
25};
26
27#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
28
29static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
30				     const struct word_at_a_time *c)
31{
32	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
33	*bits = mask;
34	return mask;
35}
36
37#define prep_zero_mask(a, bits, c) (bits)
38
39static inline unsigned long create_zero_mask(unsigned long bits)
40{
41	bits = (bits - 1) & ~bits;
42	return bits >> 7;
43}
44
45static inline unsigned long find_zero(unsigned long mask)
46{
47	return fls64(mask) >> 3;
48}
49
50#define zero_bytemask(mask) (mask)
51
52#else	/* __AARCH64EB__ */
53#include <asm-generic/word-at-a-time.h>
54#endif
55
56/*
57 * Load an unaligned word from kernel space.
58 *
59 * In the (very unlikely) case of the word being a page-crosser
60 * and the next page not being mapped, take the exception and
61 * return zeroes in the non-existing part.
62 */
63static inline unsigned long load_unaligned_zeropad(const void *addr)
64{
65	unsigned long ret, offset;
66
67	/* Load word from unaligned pointer addr */
68	asm(
69	"1:	ldr	%0, %3\n"
70	"2:\n"
71	"	.pushsection .fixup,\"ax\"\n"
72	"	.align 2\n"
73	"3:	and	%1, %2, #0x7\n"
74	"	bic	%2, %2, #0x7\n"
75	"	ldr	%0, [%2]\n"
76	"	lsl	%1, %1, #0x3\n"
77#ifndef __AARCH64EB__
78	"	lsr	%0, %0, %1\n"
79#else
80	"	lsl	%0, %0, %1\n"
81#endif
82	"	b	2b\n"
83	"	.popsection\n"
84	"	.pushsection __ex_table,\"a\"\n"
85	"	.align	3\n"
86	"	.quad	1b, 3b\n"
87	"	.popsection"
88	: "=&r" (ret), "=&r" (offset)
89	: "r" (addr), "Q" (*(unsigned long *)addr));
90
91	return ret;
92}
93
94#endif /* __ASM_WORD_AT_A_TIME_H */
95