1 /*
2 * Based on arch/arm/include/asm/barrier.h
3 *
4 * Copyright (C) 2012 ARM Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18 #ifndef __ASM_BARRIER_H
19 #define __ASM_BARRIER_H
20
21 #ifndef __ASSEMBLY__
22
23 #define __nops(n) ".rept " #n "\nnop\n.endr\n"
24 #define nops(n) asm volatile(__nops(n))
25
26 #define sev() asm volatile("sev" : : : "memory")
27 #define wfe() asm volatile("wfe" : : : "memory")
28 #define wfi() asm volatile("wfi" : : : "memory")
29
30 #define isb() asm volatile("isb" : : : "memory")
31 #define dmb(opt) asm volatile("dmb " #opt : : : "memory")
32 #define dsb(opt) asm volatile("dsb " #opt : : : "memory")
33
34 #define psb_csync() asm volatile("hint #17" : : : "memory")
35 #define csdb() asm volatile("hint #20" : : : "memory")
36
37 #define mb() dsb(sy)
38 #define rmb() dsb(ld)
39 #define wmb() dsb(st)
40
41 #define dma_rmb() dmb(oshld)
42 #define dma_wmb() dmb(oshst)
43
44 /*
45 * Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz
46 * and 0 otherwise.
47 */
48 #define array_index_mask_nospec array_index_mask_nospec
array_index_mask_nospec(unsigned long idx,unsigned long sz)49 static inline unsigned long array_index_mask_nospec(unsigned long idx,
50 unsigned long sz)
51 {
52 unsigned long mask;
53
54 asm volatile(
55 " cmp %1, %2\n"
56 " sbc %0, xzr, xzr\n"
57 : "=r" (mask)
58 : "r" (idx), "Ir" (sz)
59 : "cc");
60
61 csdb();
62 return mask;
63 }
64
65 #define __smp_mb() dmb(ish)
66 #define __smp_rmb() dmb(ishld)
67 #define __smp_wmb() dmb(ishst)
68
69 #define __smp_store_release(p, v) \
70 do { \
71 union { typeof(*p) __val; char __c[1]; } __u = \
72 { .__val = (__force typeof(*p)) (v) }; \
73 compiletime_assert_atomic_type(*p); \
74 switch (sizeof(*p)) { \
75 case 1: \
76 asm volatile ("stlrb %w1, %0" \
77 : "=Q" (*p) \
78 : "r" (*(__u8 *)__u.__c) \
79 : "memory"); \
80 break; \
81 case 2: \
82 asm volatile ("stlrh %w1, %0" \
83 : "=Q" (*p) \
84 : "r" (*(__u16 *)__u.__c) \
85 : "memory"); \
86 break; \
87 case 4: \
88 asm volatile ("stlr %w1, %0" \
89 : "=Q" (*p) \
90 : "r" (*(__u32 *)__u.__c) \
91 : "memory"); \
92 break; \
93 case 8: \
94 asm volatile ("stlr %1, %0" \
95 : "=Q" (*p) \
96 : "r" (*(__u64 *)__u.__c) \
97 : "memory"); \
98 break; \
99 } \
100 } while (0)
101
102 #define __smp_load_acquire(p) \
103 ({ \
104 union { typeof(*p) __val; char __c[1]; } __u; \
105 compiletime_assert_atomic_type(*p); \
106 switch (sizeof(*p)) { \
107 case 1: \
108 asm volatile ("ldarb %w0, %1" \
109 : "=r" (*(__u8 *)__u.__c) \
110 : "Q" (*p) : "memory"); \
111 break; \
112 case 2: \
113 asm volatile ("ldarh %w0, %1" \
114 : "=r" (*(__u16 *)__u.__c) \
115 : "Q" (*p) : "memory"); \
116 break; \
117 case 4: \
118 asm volatile ("ldar %w0, %1" \
119 : "=r" (*(__u32 *)__u.__c) \
120 : "Q" (*p) : "memory"); \
121 break; \
122 case 8: \
123 asm volatile ("ldar %0, %1" \
124 : "=r" (*(__u64 *)__u.__c) \
125 : "Q" (*p) : "memory"); \
126 break; \
127 } \
128 __u.__val; \
129 })
130
131 #define smp_cond_load_relaxed(ptr, cond_expr) \
132 ({ \
133 typeof(ptr) __PTR = (ptr); \
134 typeof(*ptr) VAL; \
135 for (;;) { \
136 VAL = READ_ONCE(*__PTR); \
137 if (cond_expr) \
138 break; \
139 __cmpwait_relaxed(__PTR, VAL); \
140 } \
141 VAL; \
142 })
143
144 #define smp_cond_load_acquire(ptr, cond_expr) \
145 ({ \
146 typeof(ptr) __PTR = (ptr); \
147 typeof(*ptr) VAL; \
148 for (;;) { \
149 VAL = smp_load_acquire(__PTR); \
150 if (cond_expr) \
151 break; \
152 __cmpwait_relaxed(__PTR, VAL); \
153 } \
154 VAL; \
155 })
156
157 #include <asm-generic/barrier.h>
158
159 #endif /* __ASSEMBLY__ */
160
161 #endif /* __ASM_BARRIER_H */
162
