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 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