blob: 422a47746657af80c0b9dc035e245affe862dbc8 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_WORD_AT_A_TIME_H
#define _ASM_WORD_AT_A_TIME_H
#include <linux/bitops.h>
#include <linux/wordpart.h>
struct word_at_a_time {
const unsigned long one_bits, high_bits;
};
#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
/* Return nonzero if it has a zero */
static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
{
unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
*bits = mask;
return mask;
}
static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
{
return bits;
}
#ifdef CONFIG_64BIT
/* Keep the initial has_zero() value for both bitmask and size calc */
#define create_zero_mask(bits) (bits)
static inline unsigned long zero_bytemask(unsigned long bits)
{
bits = (bits - 1) & ~bits;
return bits >> 7;
}
#define find_zero(bits) (__ffs(bits) >> 3)
#else
/* Create the final mask for both bytemask and size */
static inline unsigned long create_zero_mask(unsigned long bits)
{
bits = (bits - 1) & ~bits;
return bits >> 7;
}
/* The mask we created is directly usable as a bytemask */
#define zero_bytemask(mask) (mask)
/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
static inline unsigned long find_zero(unsigned long mask)
{
/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
long a = (0x0ff0001+mask) >> 23;
/* Fix the 1 for 00 case */
return a & mask;
}
#endif
/*
* Load an unaligned word from kernel space.
*
* In the (very unlikely) case of the word being a page-crosser
* and the next page not being mapped, take the exception and
* return zeroes in the non-existing part.
*/
static inline unsigned long load_unaligned_zeropad(const void *addr)
{
unsigned long ret;
asm volatile(
"1: mov %[mem], %[ret]\n"
"2:\n"
_ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_ZEROPAD)
: [ret] "=r" (ret)
: [mem] "m" (*(unsigned long *)addr));
return ret;
}
#endif /* _ASM_WORD_AT_A_TIME_H */
|
