1#ifndef __ASM_ARM_WORD_AT_A_TIME_H
2#define __ASM_ARM_WORD_AT_A_TIME_H
3
4#ifndef __ARMEB__
5
6/*
7 * Little-endian word-at-a-time zero byte handling.
8 * Heavily based on the x86 algorithm.
9 */
10#include <linux/kernel.h>
11
12struct word_at_a_time {
13	const unsigned long one_bits, high_bits;
14};
15
16#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
17
18static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
19				     const struct word_at_a_time *c)
20{
21	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
22	*bits = mask;
23	return mask;
24}
25
26#define prep_zero_mask(a, bits, c) (bits)
27
28static inline unsigned long create_zero_mask(unsigned long bits)
29{
30	bits = (bits - 1) & ~bits;
31	return bits >> 7;
32}
33
34static inline unsigned long find_zero(unsigned long mask)
35{
36	unsigned long ret;
37
38#if __LINUX_ARM_ARCH__ >= 5
39	/* We have clz available. */
40	ret = fls(mask) >> 3;
41#else
42	/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
43	ret = (0x0ff0001 + mask) >> 23;
44	/* Fix the 1 for 00 case */
45	ret &= mask;
46#endif
47
48	return ret;
49}
50
51#define zero_bytemask(mask) (mask)
52
53#else	/* __ARMEB__ */
54#include <asm-generic/word-at-a-time.h>
55#endif
56
57#ifdef CONFIG_DCACHE_WORD_ACCESS
58
59/*
60 * Load an unaligned word from kernel space.
61 *
62 * In the (very unlikely) case of the word being a page-crosser
63 * and the next page not being mapped, take the exception and
64 * return zeroes in the non-existing part.
65 */
66static inline unsigned long load_unaligned_zeropad(const void *addr)
67{
68	unsigned long ret, offset;
69
70	/* Load word from unaligned pointer addr */
71	asm(
72	"1:	ldr	%0, [%2]\n"
73	"2:\n"
74	"	.pushsection .text.fixup,\"ax\"\n"
75	"	.align 2\n"
76	"3:	and	%1, %2, #0x3\n"
77	"	bic	%2, %2, #0x3\n"
78	"	ldr	%0, [%2]\n"
79	"	lsl	%1, %1, #0x3\n"
80#ifndef __ARMEB__
81	"	lsr	%0, %0, %1\n"
82#else
83	"	lsl	%0, %0, %1\n"
84#endif
85	"	b	2b\n"
86	"	.popsection\n"
87	"	.pushsection __ex_table,\"a\"\n"
88	"	.align	3\n"
89	"	.long	1b, 3b\n"
90	"	.popsection"
91	: "=&r" (ret), "=&r" (offset)
92	: "r" (addr), "Qo" (*(unsigned long *)addr));
93
94	return ret;
95}
96
97#endif	/* DCACHE_WORD_ACCESS */
98#endif /* __ASM_ARM_WORD_AT_A_TIME_H */
99