1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-only */
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2013 ARM Ltd.
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun #ifndef __ASM_WORD_AT_A_TIME_H
6*4882a593Smuzhiyun #define __ASM_WORD_AT_A_TIME_H
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/uaccess.h>
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #ifndef __AARCH64EB__
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/kernel.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun struct word_at_a_time {
15*4882a593Smuzhiyun const unsigned long one_bits, high_bits;
16*4882a593Smuzhiyun };
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
19*4882a593Smuzhiyun
has_zero(unsigned long a,unsigned long * bits,const struct word_at_a_time * c)20*4882a593Smuzhiyun static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
21*4882a593Smuzhiyun const struct word_at_a_time *c)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
24*4882a593Smuzhiyun *bits = mask;
25*4882a593Smuzhiyun return mask;
26*4882a593Smuzhiyun }
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun #define prep_zero_mask(a, bits, c) (bits)
29*4882a593Smuzhiyun
create_zero_mask(unsigned long bits)30*4882a593Smuzhiyun static inline unsigned long create_zero_mask(unsigned long bits)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun bits = (bits - 1) & ~bits;
33*4882a593Smuzhiyun return bits >> 7;
34*4882a593Smuzhiyun }
35*4882a593Smuzhiyun
find_zero(unsigned long mask)36*4882a593Smuzhiyun static inline unsigned long find_zero(unsigned long mask)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun return fls64(mask) >> 3;
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun #define zero_bytemask(mask) (mask)
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun #else /* __AARCH64EB__ */
44*4882a593Smuzhiyun #include <asm-generic/word-at-a-time.h>
45*4882a593Smuzhiyun #endif
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun /*
48*4882a593Smuzhiyun * Load an unaligned word from kernel space.
49*4882a593Smuzhiyun *
50*4882a593Smuzhiyun * In the (very unlikely) case of the word being a page-crosser
51*4882a593Smuzhiyun * and the next page not being mapped, take the exception and
52*4882a593Smuzhiyun * return zeroes in the non-existing part.
53*4882a593Smuzhiyun */
load_unaligned_zeropad(const void * addr)54*4882a593Smuzhiyun static inline unsigned long load_unaligned_zeropad(const void *addr)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun unsigned long ret, tmp;
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun __uaccess_enable_tco_async();
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun /* Load word from unaligned pointer addr */
61*4882a593Smuzhiyun asm(
62*4882a593Smuzhiyun "1: ldr %0, %3\n"
63*4882a593Smuzhiyun "2:\n"
64*4882a593Smuzhiyun " .pushsection .fixup,\"ax\"\n"
65*4882a593Smuzhiyun " .align 2\n"
66*4882a593Smuzhiyun "3: bic %1, %2, #0x7\n"
67*4882a593Smuzhiyun " ldr %0, [%1]\n"
68*4882a593Smuzhiyun " and %1, %2, #0x7\n"
69*4882a593Smuzhiyun " lsl %1, %1, #0x3\n"
70*4882a593Smuzhiyun #ifndef __AARCH64EB__
71*4882a593Smuzhiyun " lsr %0, %0, %1\n"
72*4882a593Smuzhiyun #else
73*4882a593Smuzhiyun " lsl %0, %0, %1\n"
74*4882a593Smuzhiyun #endif
75*4882a593Smuzhiyun " b 2b\n"
76*4882a593Smuzhiyun " .popsection\n"
77*4882a593Smuzhiyun _ASM_EXTABLE(1b, 3b)
78*4882a593Smuzhiyun : "=&r" (ret), "=&r" (tmp)
79*4882a593Smuzhiyun : "r" (addr), "Q" (*(unsigned long *)addr));
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun __uaccess_disable_tco_async();
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun return ret;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun #endif /* __ASM_WORD_AT_A_TIME_H */
87