1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_WORD_AT_A_TIME_H
3 #define _ASM_WORD_AT_A_TIME_H
4
5 #include <linux/bitops.h>
6 #include <linux/wordpart.h>
7 #include <asm/asm-extable.h>
8 #include <asm/bitsperlong.h>
9
10 struct word_at_a_time {
11 const unsigned long bits;
12 };
13
14 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x7f) }
15
16 static inline unsigned long prep_zero_mask(unsigned long val, unsigned long data, const struct word_at_a_time *c)
17 {
18 return data;
19 }
20
21 static inline unsigned long create_zero_mask(unsigned long data)
22 {
23 return __fls(data);
24 }
25
26 static inline unsigned long find_zero(unsigned long data)
27 {
28 return (data ^ (BITS_PER_LONG - 1)) >> 3;
29 }
30
31 static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
32 {
33 unsigned long mask = (val & c->bits) + c->bits;
34
35 *data = ~(mask | val | c->bits);
36 return *data;
37 }
38
39 static inline unsigned long zero_bytemask(unsigned long data)
40 {
41 return ~1UL << data;
42 }
43
44 /*
45 * Load an unaligned word from kernel space.
46 *
47 * In the (very unlikely) case of the word being a page-crosser
48 * and the next page not being mapped, take the exception and
49 * return zeroes in the non-existing part.
50 */
51 static inline unsigned long load_unaligned_zeropad(const void *addr)
52 {
53 unsigned long data;
54
55 asm volatile(
56 "0: lg %[data],0(%[addr])\n"
57 "1: nopr %%r7\n"
58 EX_TABLE_ZEROPAD(0b, 1b, %[data], %[addr])
59 EX_TABLE_ZEROPAD(1b, 1b, %[data], %[addr])
60 : [data] "=d" (data)
61 : [addr] "a" (addr), "m" (*(unsigned long *)addr));
62 return data;
63 }
64
65 #endif /* _ASM_WORD_AT_A_TIME_H */
66
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