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/kernel.h>
13
14 struct word_at_a_time {
15 const unsigned long one_bits, high_bits;
16 };
17
18 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
19
has_zero(unsigned long a,unsigned long * bits,const struct word_at_a_time * c)20 static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
21 const struct word_at_a_time *c)
22 {
23 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
24 *bits = mask;
25 return mask;
26 }
27
28 #define prep_zero_mask(a, bits, c) (bits)
29
create_zero_mask(unsigned long bits)30 static inline unsigned long create_zero_mask(unsigned long bits)
31 {
32 bits = (bits - 1) & ~bits;
33 return bits >> 7;
34 }
35
find_zero(unsigned long mask)36 static inline unsigned long find_zero(unsigned long mask)
37 {
38 return fls64(mask) >> 3;
39 }
40
41 #define zero_bytemask(mask) (mask)
42
43 #else /* __AARCH64EB__ */
44 #include <asm-generic/word-at-a-time.h>
45 #endif
46
47 /*
48 * Load an unaligned word from kernel space.
49 *
50 * In the (very unlikely) case of the word being a page-crosser
51 * and the next page not being mapped, take the exception and
52 * return zeroes in the non-existing part.
53 */
load_unaligned_zeropad(const void * addr)54 static inline unsigned long load_unaligned_zeropad(const void *addr)
55 {
56 unsigned long ret, offset;
57
58 /* Load word from unaligned pointer addr */
59 asm(
60 "1: ldr %0, %3\n"
61 "2:\n"
62 " .pushsection .fixup,\"ax\"\n"
63 " .align 2\n"
64 "3: and %1, %2, #0x7\n"
65 " bic %2, %2, #0x7\n"
66 " ldr %0, [%2]\n"
67 " lsl %1, %1, #0x3\n"
68 #ifndef __AARCH64EB__
69 " lsr %0, %0, %1\n"
70 #else
71 " lsl %0, %0, %1\n"
72 #endif
73 " b 2b\n"
74 " .popsection\n"
75 _ASM_EXTABLE(1b, 3b)
76 : "=&r" (ret), "=&r" (offset)
77 : "r" (addr), "Q" (*(unsigned long *)addr));
78
79 return ret;
80 }
81
82 #endif /* __ASM_WORD_AT_A_TIME_H */
83
