1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #ifndef _ASM_ARC_ATOMIC_H 10 #define _ASM_ARC_ATOMIC_H 11 12 #ifndef __ASSEMBLY__ 13 14 #include <linux/types.h> 15 #include <linux/compiler.h> 16 #include <asm/cmpxchg.h> 17 #include <asm/barrier.h> 18 #include <asm/smp.h> 19 20 #define atomic_read(v) READ_ONCE((v)->counter) 21 22 #ifdef CONFIG_ARC_HAS_LLSC 23 24 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) 25 26 #ifdef CONFIG_ARC_STAR_9000923308 27 28 #define SCOND_FAIL_RETRY_VAR_DEF \ 29 unsigned int delay = 1, tmp; \ 30 31 #define SCOND_FAIL_RETRY_ASM \ 32 " bz 4f \n" \ 33 " ; --- scond fail delay --- \n" \ 34 " mov %[tmp], %[delay] \n" /* tmp = delay */ \ 35 "2: brne.d %[tmp], 0, 2b \n" /* while (tmp != 0) */ \ 36 " sub %[tmp], %[tmp], 1 \n" /* tmp-- */ \ 37 " rol %[delay], %[delay] \n" /* delay *= 2 */ \ 38 " b 1b \n" /* start over */ \ 39 "4: ; --- success --- \n" \ 40 41 #define SCOND_FAIL_RETRY_VARS \ 42 ,[delay] "+&r" (delay),[tmp] "=&r" (tmp) \ 43 44 #else /* !CONFIG_ARC_STAR_9000923308 */ 45 46 #define SCOND_FAIL_RETRY_VAR_DEF 47 48 #define SCOND_FAIL_RETRY_ASM \ 49 " bnz 1b \n" \ 50 51 #define SCOND_FAIL_RETRY_VARS 52 53 #endif 54 55 #define ATOMIC_OP(op, c_op, asm_op) \ 56 static inline void atomic_##op(int i, atomic_t *v) \ 57 { \ 58 unsigned int val; \ 59 SCOND_FAIL_RETRY_VAR_DEF \ 60 \ 61 __asm__ __volatile__( \ 62 "1: llock %[val], [%[ctr]] \n" \ 63 " " #asm_op " %[val], %[val], %[i] \n" \ 64 " scond %[val], [%[ctr]] \n" \ 65 " \n" \ 66 SCOND_FAIL_RETRY_ASM \ 67 \ 68 : [val] "=&r" (val) /* Early clobber to prevent reg reuse */ \ 69 SCOND_FAIL_RETRY_VARS \ 70 : [ctr] "r" (&v->counter), /* Not "m": llock only supports reg direct addr mode */ \ 71 [i] "ir" (i) \ 72 : "cc"); \ 73 } \ 74 75 #define ATOMIC_OP_RETURN(op, c_op, asm_op) \ 76 static inline int atomic_##op##_return(int i, atomic_t *v) \ 77 { \ 78 unsigned int val; \ 79 SCOND_FAIL_RETRY_VAR_DEF \ 80 \ 81 /* \ 82 * Explicit full memory barrier needed before/after as \ 83 * LLOCK/SCOND thmeselves don't provide any such semantics \ 84 */ \ 85 smp_mb(); \ 86 \ 87 __asm__ __volatile__( \ 88 "1: llock %[val], [%[ctr]] \n" \ 89 " " #asm_op " %[val], %[val], %[i] \n" \ 90 " scond %[val], [%[ctr]] \n" \ 91 " \n" \ 92 SCOND_FAIL_RETRY_ASM \ 93 \ 94 : [val] "=&r" (val) \ 95 SCOND_FAIL_RETRY_VARS \ 96 : [ctr] "r" (&v->counter), \ 97 [i] "ir" (i) \ 98 : "cc"); \ 99 \ 100 smp_mb(); \ 101 \ 102 return val; \ 103 } 104 105 #else /* !CONFIG_ARC_HAS_LLSC */ 106 107 #ifndef CONFIG_SMP 108 109 /* violating atomic_xxx API locking protocol in UP for optimization sake */ 110 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) 111 112 #else 113 114 static inline void atomic_set(atomic_t *v, int i) 115 { 116 /* 117 * Independent of hardware support, all of the atomic_xxx() APIs need 118 * to follow the same locking rules to make sure that a "hardware" 119 * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn 120 * sequence 121 * 122 * Thus atomic_set() despite being 1 insn (and seemingly atomic) 123 * requires the locking. 124 */ 125 unsigned long flags; 126 127 atomic_ops_lock(flags); 128 WRITE_ONCE(v->counter, i); 129 atomic_ops_unlock(flags); 130 } 131 132 #endif 133 134 /* 135 * Non hardware assisted Atomic-R-M-W 136 * Locking would change to irq-disabling only (UP) and spinlocks (SMP) 137 */ 138 139 #define ATOMIC_OP(op, c_op, asm_op) \ 140 static inline void atomic_##op(int i, atomic_t *v) \ 141 { \ 142 unsigned long flags; \ 143 \ 144 atomic_ops_lock(flags); \ 145 v->counter c_op i; \ 146 atomic_ops_unlock(flags); \ 147 } 148 149 #define ATOMIC_OP_RETURN(op, c_op, asm_op) \ 150 static inline int atomic_##op##_return(int i, atomic_t *v) \ 151 { \ 152 unsigned long flags; \ 153 unsigned long temp; \ 154 \ 155 /* \ 156 * spin lock/unlock provides the needed smp_mb() before/after \ 157 */ \ 158 atomic_ops_lock(flags); \ 159 temp = v->counter; \ 160 temp c_op i; \ 161 v->counter = temp; \ 162 atomic_ops_unlock(flags); \ 163 \ 164 return temp; \ 165 } 166 167 #endif /* !CONFIG_ARC_HAS_LLSC */ 168 169 #define ATOMIC_OPS(op, c_op, asm_op) \ 170 ATOMIC_OP(op, c_op, asm_op) \ 171 ATOMIC_OP_RETURN(op, c_op, asm_op) 172 173 ATOMIC_OPS(add, +=, add) 174 ATOMIC_OPS(sub, -=, sub) 175 176 #define atomic_andnot atomic_andnot 177 178 ATOMIC_OP(and, &=, and) 179 ATOMIC_OP(andnot, &= ~, bic) 180 ATOMIC_OP(or, |=, or) 181 ATOMIC_OP(xor, ^=, xor) 182 183 #undef ATOMIC_OPS 184 #undef ATOMIC_OP_RETURN 185 #undef ATOMIC_OP 186 #undef SCOND_FAIL_RETRY_VAR_DEF 187 #undef SCOND_FAIL_RETRY_ASM 188 #undef SCOND_FAIL_RETRY_VARS 189 190 /** 191 * __atomic_add_unless - add unless the number is a given value 192 * @v: pointer of type atomic_t 193 * @a: the amount to add to v... 194 * @u: ...unless v is equal to u. 195 * 196 * Atomically adds @a to @v, so long as it was not @u. 197 * Returns the old value of @v 198 */ 199 #define __atomic_add_unless(v, a, u) \ 200 ({ \ 201 int c, old; \ 202 \ 203 /* \ 204 * Explicit full memory barrier needed before/after as \ 205 * LLOCK/SCOND thmeselves don't provide any such semantics \ 206 */ \ 207 smp_mb(); \ 208 \ 209 c = atomic_read(v); \ 210 while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ 211 c = old; \ 212 \ 213 smp_mb(); \ 214 \ 215 c; \ 216 }) 217 218 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) 219 220 #define atomic_inc(v) atomic_add(1, v) 221 #define atomic_dec(v) atomic_sub(1, v) 222 223 #define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) 224 #define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) 225 #define atomic_inc_return(v) atomic_add_return(1, (v)) 226 #define atomic_dec_return(v) atomic_sub_return(1, (v)) 227 #define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) 228 229 #define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0) 230 231 #define ATOMIC_INIT(i) { (i) } 232 233 #include <asm-generic/atomic64.h> 234 235 #endif 236 237 #endif 238