1 /* 2 * Based on arch/arm/include/asm/cmpxchg.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_CMPXCHG_H 19 #define __ASM_CMPXCHG_H 20 21 #include <linux/build_bug.h> 22 23 #include <asm/atomic.h> 24 #include <asm/barrier.h> 25 #include <asm/lse.h> 26 27 /* 28 * We need separate acquire parameters for ll/sc and lse, since the full 29 * barrier case is generated as release+dmb for the former and 30 * acquire+release for the latter. 31 */ 32 #define __XCHG_CASE(w, sz, name, mb, nop_lse, acq, acq_lse, rel, cl) \ 33 static inline unsigned long __xchg_case_##name(unsigned long x, \ 34 volatile void *ptr) \ 35 { \ 36 unsigned long ret, tmp; \ 37 \ 38 asm volatile(ARM64_LSE_ATOMIC_INSN( \ 39 /* LL/SC */ \ 40 " prfm pstl1strm, %2\n" \ 41 "1: ld" #acq "xr" #sz "\t%" #w "0, %2\n" \ 42 " st" #rel "xr" #sz "\t%w1, %" #w "3, %2\n" \ 43 " cbnz %w1, 1b\n" \ 44 " " #mb, \ 45 /* LSE atomics */ \ 46 " swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n" \ 47 __nops(3) \ 48 " " #nop_lse) \ 49 : "=&r" (ret), "=&r" (tmp), "+Q" (*(unsigned long *)ptr) \ 50 : "r" (x) \ 51 : cl); \ 52 \ 53 return ret; \ 54 } 55 56 __XCHG_CASE(w, b, 1, , , , , , ) 57 __XCHG_CASE(w, h, 2, , , , , , ) 58 __XCHG_CASE(w, , 4, , , , , , ) 59 __XCHG_CASE( , , 8, , , , , , ) 60 __XCHG_CASE(w, b, acq_1, , , a, a, , "memory") 61 __XCHG_CASE(w, h, acq_2, , , a, a, , "memory") 62 __XCHG_CASE(w, , acq_4, , , a, a, , "memory") 63 __XCHG_CASE( , , acq_8, , , a, a, , "memory") 64 __XCHG_CASE(w, b, rel_1, , , , , l, "memory") 65 __XCHG_CASE(w, h, rel_2, , , , , l, "memory") 66 __XCHG_CASE(w, , rel_4, , , , , l, "memory") 67 __XCHG_CASE( , , rel_8, , , , , l, "memory") 68 __XCHG_CASE(w, b, mb_1, dmb ish, nop, , a, l, "memory") 69 __XCHG_CASE(w, h, mb_2, dmb ish, nop, , a, l, "memory") 70 __XCHG_CASE(w, , mb_4, dmb ish, nop, , a, l, "memory") 71 __XCHG_CASE( , , mb_8, dmb ish, nop, , a, l, "memory") 72 73 #undef __XCHG_CASE 74 75 #define __XCHG_GEN(sfx) \ 76 static inline unsigned long __xchg##sfx(unsigned long x, \ 77 volatile void *ptr, \ 78 int size) \ 79 { \ 80 switch (size) { \ 81 case 1: \ 82 return __xchg_case##sfx##_1(x, ptr); \ 83 case 2: \ 84 return __xchg_case##sfx##_2(x, ptr); \ 85 case 4: \ 86 return __xchg_case##sfx##_4(x, ptr); \ 87 case 8: \ 88 return __xchg_case##sfx##_8(x, ptr); \ 89 default: \ 90 BUILD_BUG(); \ 91 } \ 92 \ 93 unreachable(); \ 94 } 95 96 __XCHG_GEN() 97 __XCHG_GEN(_acq) 98 __XCHG_GEN(_rel) 99 __XCHG_GEN(_mb) 100 101 #undef __XCHG_GEN 102 103 #define __xchg_wrapper(sfx, ptr, x) \ 104 ({ \ 105 __typeof__(*(ptr)) __ret; \ 106 __ret = (__typeof__(*(ptr))) \ 107 __xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \ 108 __ret; \ 109 }) 110 111 /* xchg */ 112 #define xchg_relaxed(...) __xchg_wrapper( , __VA_ARGS__) 113 #define xchg_acquire(...) __xchg_wrapper(_acq, __VA_ARGS__) 114 #define xchg_release(...) __xchg_wrapper(_rel, __VA_ARGS__) 115 #define xchg(...) __xchg_wrapper( _mb, __VA_ARGS__) 116 117 #define __CMPXCHG_GEN(sfx) \ 118 static inline unsigned long __cmpxchg##sfx(volatile void *ptr, \ 119 unsigned long old, \ 120 unsigned long new, \ 121 int size) \ 122 { \ 123 switch (size) { \ 124 case 1: \ 125 return __cmpxchg_case##sfx##_1(ptr, (u8)old, new); \ 126 case 2: \ 127 return __cmpxchg_case##sfx##_2(ptr, (u16)old, new); \ 128 case 4: \ 129 return __cmpxchg_case##sfx##_4(ptr, old, new); \ 130 case 8: \ 131 return __cmpxchg_case##sfx##_8(ptr, old, new); \ 132 default: \ 133 BUILD_BUG(); \ 134 } \ 135 \ 136 unreachable(); \ 137 } 138 139 __CMPXCHG_GEN() 140 __CMPXCHG_GEN(_acq) 141 __CMPXCHG_GEN(_rel) 142 __CMPXCHG_GEN(_mb) 143 144 #undef __CMPXCHG_GEN 145 146 #define __cmpxchg_wrapper(sfx, ptr, o, n) \ 147 ({ \ 148 __typeof__(*(ptr)) __ret; \ 149 __ret = (__typeof__(*(ptr))) \ 150 __cmpxchg##sfx((ptr), (unsigned long)(o), \ 151 (unsigned long)(n), sizeof(*(ptr))); \ 152 __ret; \ 153 }) 154 155 /* cmpxchg */ 156 #define cmpxchg_relaxed(...) __cmpxchg_wrapper( , __VA_ARGS__) 157 #define cmpxchg_acquire(...) __cmpxchg_wrapper(_acq, __VA_ARGS__) 158 #define cmpxchg_release(...) __cmpxchg_wrapper(_rel, __VA_ARGS__) 159 #define cmpxchg(...) __cmpxchg_wrapper( _mb, __VA_ARGS__) 160 #define cmpxchg_local cmpxchg_relaxed 161 162 /* cmpxchg64 */ 163 #define cmpxchg64_relaxed cmpxchg_relaxed 164 #define cmpxchg64_acquire cmpxchg_acquire 165 #define cmpxchg64_release cmpxchg_release 166 #define cmpxchg64 cmpxchg 167 #define cmpxchg64_local cmpxchg_local 168 169 /* cmpxchg_double */ 170 #define system_has_cmpxchg_double() 1 171 172 #define __cmpxchg_double_check(ptr1, ptr2) \ 173 ({ \ 174 if (sizeof(*(ptr1)) != 8) \ 175 BUILD_BUG(); \ 176 VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1); \ 177 }) 178 179 #define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \ 180 ({\ 181 int __ret;\ 182 __cmpxchg_double_check(ptr1, ptr2); \ 183 __ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \ 184 (unsigned long)(n1), (unsigned long)(n2), \ 185 ptr1); \ 186 __ret; \ 187 }) 188 189 #define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \ 190 ({\ 191 int __ret;\ 192 __cmpxchg_double_check(ptr1, ptr2); \ 193 __ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \ 194 (unsigned long)(n1), (unsigned long)(n2), \ 195 ptr1); \ 196 __ret; \ 197 }) 198 199 #define __CMPWAIT_CASE(w, sz, name) \ 200 static inline void __cmpwait_case_##name(volatile void *ptr, \ 201 unsigned long val) \ 202 { \ 203 unsigned long tmp; \ 204 \ 205 asm volatile( \ 206 " ldxr" #sz "\t%" #w "[tmp], %[v]\n" \ 207 " eor %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n" \ 208 " cbnz %" #w "[tmp], 1f\n" \ 209 " wfe\n" \ 210 "1:" \ 211 : [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr) \ 212 : [val] "r" (val)); \ 213 } 214 215 __CMPWAIT_CASE(w, b, 1); 216 __CMPWAIT_CASE(w, h, 2); 217 __CMPWAIT_CASE(w, , 4); 218 __CMPWAIT_CASE( , , 8); 219 220 #undef __CMPWAIT_CASE 221 222 #define __CMPWAIT_GEN(sfx) \ 223 static inline void __cmpwait##sfx(volatile void *ptr, \ 224 unsigned long val, \ 225 int size) \ 226 { \ 227 switch (size) { \ 228 case 1: \ 229 return __cmpwait_case##sfx##_1(ptr, (u8)val); \ 230 case 2: \ 231 return __cmpwait_case##sfx##_2(ptr, (u16)val); \ 232 case 4: \ 233 return __cmpwait_case##sfx##_4(ptr, val); \ 234 case 8: \ 235 return __cmpwait_case##sfx##_8(ptr, val); \ 236 default: \ 237 BUILD_BUG(); \ 238 } \ 239 \ 240 unreachable(); \ 241 } 242 243 __CMPWAIT_GEN() 244 245 #undef __CMPWAIT_GEN 246 247 #define __cmpwait_relaxed(ptr, val) \ 248 __cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr))) 249 250 #endif /* __ASM_CMPXCHG_H */ 251