1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
4 */
5#ifndef __ASM_BARRIER_H
6#define __ASM_BARRIER_H
7
8/*
9 * Hint encoding:
10 *
11 * Bit4: ordering or completion (0: completion, 1: ordering)
12 * Bit3: barrier for previous read (0: true, 1: false)
13 * Bit2: barrier for previous write (0: true, 1: false)
14 * Bit1: barrier for succeeding read (0: true, 1: false)
15 * Bit0: barrier for succeeding write (0: true, 1: false)
16 *
17 * Hint 0x700: barrier for "read after read" from the same address
18 */
19
20#define DBAR(hint) __asm__ __volatile__("dbar %0 " : : "I"(hint) : "memory")
21
22#define crwrw		0b00000
23#define cr_r_		0b00101
24#define c_w_w		0b01010
25
26#define orwrw		0b10000
27#define or_r_		0b10101
28#define o_w_w		0b11010
29
30#define orw_w		0b10010
31#define or_rw		0b10100
32
33#define c_sync()	DBAR(crwrw)
34#define c_rsync()	DBAR(cr_r_)
35#define c_wsync()	DBAR(c_w_w)
36
37#define o_sync()	DBAR(orwrw)
38#define o_rsync()	DBAR(or_r_)
39#define o_wsync()	DBAR(o_w_w)
40
41#define ldacq_mb()	DBAR(or_rw)
42#define strel_mb()	DBAR(orw_w)
43
44#define mb()		c_sync()
45#define rmb()		c_rsync()
46#define wmb()		c_wsync()
47#define iob()		c_sync()
48#define wbflush()	c_sync()
49
50#define __smp_mb()	o_sync()
51#define __smp_rmb()	o_rsync()
52#define __smp_wmb()	o_wsync()
53
54#ifdef CONFIG_SMP
55#define __WEAK_LLSC_MB		"	dbar 0x700	\n"
56#else
57#define __WEAK_LLSC_MB		"			\n"
58#endif
59
60#define __smp_mb__before_atomic()	barrier()
61#define __smp_mb__after_atomic()	barrier()
62
63/**
64 * array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
65 * @index: array element index
66 * @size: number of elements in array
67 *
68 * Returns:
69 *     0 - (@index < @size)
70 */
71#define array_index_mask_nospec array_index_mask_nospec
72static inline unsigned long array_index_mask_nospec(unsigned long index,
73						    unsigned long size)
74{
75	unsigned long mask;
76
77	__asm__ __volatile__(
78		"sltu	%0, %1, %2\n\t"
79#if (__SIZEOF_LONG__ == 4)
80		"sub.w	%0, $zero, %0\n\t"
81#elif (__SIZEOF_LONG__ == 8)
82		"sub.d	%0, $zero, %0\n\t"
83#endif
84		: "=r" (mask)
85		: "r" (index), "r" (size)
86		:);
87
88	return mask;
89}
90
91#define __smp_load_acquire(p)				\
92({							\
93	typeof(*p) ___p1 = READ_ONCE(*p);		\
94	compiletime_assert_atomic_type(*p);		\
95	ldacq_mb();					\
96	___p1;						\
97})
98
99#define __smp_store_release(p, v)			\
100do {							\
101	compiletime_assert_atomic_type(*p);		\
102	strel_mb();					\
103	WRITE_ONCE(*p, v);				\
104} while (0)
105
106#define __smp_store_mb(p, v)							\
107do {										\
108	union { typeof(p) __val; char __c[1]; } __u =				\
109		{ .__val = (__force typeof(p)) (v) };				\
110	unsigned long __tmp;							\
111	switch (sizeof(p)) {							\
112	case 1:									\
113		*(volatile __u8 *)&p = *(__u8 *)__u.__c;			\
114		__smp_mb();							\
115		break;								\
116	case 2:									\
117		*(volatile __u16 *)&p = *(__u16 *)__u.__c;			\
118		__smp_mb();							\
119		break;								\
120	case 4:									\
121		__asm__ __volatile__(						\
122		"amswap_db.w %[tmp], %[val], %[mem]	\n"			\
123		: [mem] "+ZB" (*(u32 *)&p), [tmp] "=&r" (__tmp)			\
124		: [val] "r" (*(__u32 *)__u.__c)					\
125		: );								\
126		break;								\
127	case 8:									\
128		__asm__ __volatile__(						\
129		"amswap_db.d %[tmp], %[val], %[mem]	\n"			\
130		: [mem] "+ZB" (*(u64 *)&p), [tmp] "=&r" (__tmp)			\
131		: [val] "r" (*(__u64 *)__u.__c)					\
132		: );								\
133		break;								\
134	}									\
135} while (0)
136
137#include <asm-generic/barrier.h>
138
139#endif /* __ASM_BARRIER_H */
140