1 /* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> 2 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org> 3 */ 4 5 #ifndef _ASM_PARISC_ATOMIC_H_ 6 #define _ASM_PARISC_ATOMIC_H_ 7 8 #include <linux/types.h> 9 #include <asm/cmpxchg.h> 10 #include <asm/barrier.h> 11 12 /* 13 * Atomic operations that C can't guarantee us. Useful for 14 * resource counting etc.. 15 * 16 * And probably incredibly slow on parisc. OTOH, we don't 17 * have to write any serious assembly. prumpf 18 */ 19 20 #ifdef CONFIG_SMP 21 #include <asm/spinlock.h> 22 #include <asm/cache.h> /* we use L1_CACHE_BYTES */ 23 24 /* Use an array of spinlocks for our atomic_ts. 25 * Hash function to index into a different SPINLOCK. 26 * Since "a" is usually an address, use one spinlock per cacheline. 27 */ 28 # define ATOMIC_HASH_SIZE 4 29 # define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ])) 30 31 extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned; 32 33 /* Can't use raw_spin_lock_irq because of #include problems, so 34 * this is the substitute */ 35 #define _atomic_spin_lock_irqsave(l,f) do { \ 36 arch_spinlock_t *s = ATOMIC_HASH(l); \ 37 local_irq_save(f); \ 38 arch_spin_lock(s); \ 39 } while(0) 40 41 #define _atomic_spin_unlock_irqrestore(l,f) do { \ 42 arch_spinlock_t *s = ATOMIC_HASH(l); \ 43 arch_spin_unlock(s); \ 44 local_irq_restore(f); \ 45 } while(0) 46 47 48 #else 49 # define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0) 50 # define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0) 51 #endif 52 53 /* 54 * Note that we need not lock read accesses - aligned word writes/reads 55 * are atomic, so a reader never sees inconsistent values. 56 */ 57 58 static __inline__ void atomic_set(atomic_t *v, int i) 59 { 60 unsigned long flags; 61 _atomic_spin_lock_irqsave(v, flags); 62 63 v->counter = i; 64 65 _atomic_spin_unlock_irqrestore(v, flags); 66 } 67 68 static __inline__ int atomic_read(const atomic_t *v) 69 { 70 return READ_ONCE((v)->counter); 71 } 72 73 /* exported interface */ 74 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) 75 #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) 76 77 /** 78 * __atomic_add_unless - add unless the number is a given value 79 * @v: pointer of type atomic_t 80 * @a: the amount to add to v... 81 * @u: ...unless v is equal to u. 82 * 83 * Atomically adds @a to @v, so long as it was not @u. 84 * Returns the old value of @v. 85 */ 86 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) 87 { 88 int c, old; 89 c = atomic_read(v); 90 for (;;) { 91 if (unlikely(c == (u))) 92 break; 93 old = atomic_cmpxchg((v), c, c + (a)); 94 if (likely(old == c)) 95 break; 96 c = old; 97 } 98 return c; 99 } 100 101 #define ATOMIC_OP(op, c_op) \ 102 static __inline__ void atomic_##op(int i, atomic_t *v) \ 103 { \ 104 unsigned long flags; \ 105 \ 106 _atomic_spin_lock_irqsave(v, flags); \ 107 v->counter c_op i; \ 108 _atomic_spin_unlock_irqrestore(v, flags); \ 109 } \ 110 111 #define ATOMIC_OP_RETURN(op, c_op) \ 112 static __inline__ int atomic_##op##_return(int i, atomic_t *v) \ 113 { \ 114 unsigned long flags; \ 115 int ret; \ 116 \ 117 _atomic_spin_lock_irqsave(v, flags); \ 118 ret = (v->counter c_op i); \ 119 _atomic_spin_unlock_irqrestore(v, flags); \ 120 \ 121 return ret; \ 122 } 123 124 #define ATOMIC_FETCH_OP(op, c_op) \ 125 static __inline__ int atomic_fetch_##op(int i, atomic_t *v) \ 126 { \ 127 unsigned long flags; \ 128 int ret; \ 129 \ 130 _atomic_spin_lock_irqsave(v, flags); \ 131 ret = v->counter; \ 132 v->counter c_op i; \ 133 _atomic_spin_unlock_irqrestore(v, flags); \ 134 \ 135 return ret; \ 136 } 137 138 #define ATOMIC_OPS(op, c_op) \ 139 ATOMIC_OP(op, c_op) \ 140 ATOMIC_OP_RETURN(op, c_op) \ 141 ATOMIC_FETCH_OP(op, c_op) 142 143 ATOMIC_OPS(add, +=) 144 ATOMIC_OPS(sub, -=) 145 146 #undef ATOMIC_OPS 147 #define ATOMIC_OPS(op, c_op) \ 148 ATOMIC_OP(op, c_op) \ 149 ATOMIC_FETCH_OP(op, c_op) 150 151 ATOMIC_OPS(and, &=) 152 ATOMIC_OPS(or, |=) 153 ATOMIC_OPS(xor, ^=) 154 155 #undef ATOMIC_OPS 156 #undef ATOMIC_FETCH_OP 157 #undef ATOMIC_OP_RETURN 158 #undef ATOMIC_OP 159 160 #define atomic_inc(v) (atomic_add( 1,(v))) 161 #define atomic_dec(v) (atomic_add( -1,(v))) 162 163 #define atomic_inc_return(v) (atomic_add_return( 1,(v))) 164 #define atomic_dec_return(v) (atomic_add_return( -1,(v))) 165 166 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) 167 168 /* 169 * atomic_inc_and_test - increment and test 170 * @v: pointer of type atomic_t 171 * 172 * Atomically increments @v by 1 173 * and returns true if the result is zero, or false for all 174 * other cases. 175 */ 176 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) 177 178 #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) 179 180 #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0) 181 182 #define ATOMIC_INIT(i) { (i) } 183 184 #ifdef CONFIG_64BIT 185 186 #define ATOMIC64_INIT(i) { (i) } 187 188 #define ATOMIC64_OP(op, c_op) \ 189 static __inline__ void atomic64_##op(s64 i, atomic64_t *v) \ 190 { \ 191 unsigned long flags; \ 192 \ 193 _atomic_spin_lock_irqsave(v, flags); \ 194 v->counter c_op i; \ 195 _atomic_spin_unlock_irqrestore(v, flags); \ 196 } \ 197 198 #define ATOMIC64_OP_RETURN(op, c_op) \ 199 static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v) \ 200 { \ 201 unsigned long flags; \ 202 s64 ret; \ 203 \ 204 _atomic_spin_lock_irqsave(v, flags); \ 205 ret = (v->counter c_op i); \ 206 _atomic_spin_unlock_irqrestore(v, flags); \ 207 \ 208 return ret; \ 209 } 210 211 #define ATOMIC64_FETCH_OP(op, c_op) \ 212 static __inline__ s64 atomic64_fetch_##op(s64 i, atomic64_t *v) \ 213 { \ 214 unsigned long flags; \ 215 s64 ret; \ 216 \ 217 _atomic_spin_lock_irqsave(v, flags); \ 218 ret = v->counter; \ 219 v->counter c_op i; \ 220 _atomic_spin_unlock_irqrestore(v, flags); \ 221 \ 222 return ret; \ 223 } 224 225 #define ATOMIC64_OPS(op, c_op) \ 226 ATOMIC64_OP(op, c_op) \ 227 ATOMIC64_OP_RETURN(op, c_op) \ 228 ATOMIC64_FETCH_OP(op, c_op) 229 230 ATOMIC64_OPS(add, +=) 231 ATOMIC64_OPS(sub, -=) 232 233 #undef ATOMIC64_OPS 234 #define ATOMIC64_OPS(op, c_op) \ 235 ATOMIC64_OP(op, c_op) \ 236 ATOMIC64_FETCH_OP(op, c_op) 237 238 ATOMIC64_OPS(and, &=) 239 ATOMIC64_OPS(or, |=) 240 ATOMIC64_OPS(xor, ^=) 241 242 #undef ATOMIC64_OPS 243 #undef ATOMIC64_FETCH_OP 244 #undef ATOMIC64_OP_RETURN 245 #undef ATOMIC64_OP 246 247 static __inline__ void 248 atomic64_set(atomic64_t *v, s64 i) 249 { 250 unsigned long flags; 251 _atomic_spin_lock_irqsave(v, flags); 252 253 v->counter = i; 254 255 _atomic_spin_unlock_irqrestore(v, flags); 256 } 257 258 static __inline__ s64 259 atomic64_read(const atomic64_t *v) 260 { 261 return ACCESS_ONCE((v)->counter); 262 } 263 264 #define atomic64_inc(v) (atomic64_add( 1,(v))) 265 #define atomic64_dec(v) (atomic64_add( -1,(v))) 266 267 #define atomic64_inc_return(v) (atomic64_add_return( 1,(v))) 268 #define atomic64_dec_return(v) (atomic64_add_return( -1,(v))) 269 270 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0) 271 272 #define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0) 273 #define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0) 274 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i),(v)) == 0) 275 276 /* exported interface */ 277 #define atomic64_cmpxchg(v, o, n) \ 278 ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n))) 279 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) 280 281 /** 282 * atomic64_add_unless - add unless the number is a given value 283 * @v: pointer of type atomic64_t 284 * @a: the amount to add to v... 285 * @u: ...unless v is equal to u. 286 * 287 * Atomically adds @a to @v, so long as it was not @u. 288 * Returns the old value of @v. 289 */ 290 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) 291 { 292 long c, old; 293 c = atomic64_read(v); 294 for (;;) { 295 if (unlikely(c == (u))) 296 break; 297 old = atomic64_cmpxchg((v), c, c + (a)); 298 if (likely(old == c)) 299 break; 300 c = old; 301 } 302 return c != (u); 303 } 304 305 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) 306 307 /* 308 * atomic64_dec_if_positive - decrement by 1 if old value positive 309 * @v: pointer of type atomic_t 310 * 311 * The function returns the old value of *v minus 1, even if 312 * the atomic variable, v, was not decremented. 313 */ 314 static inline long atomic64_dec_if_positive(atomic64_t *v) 315 { 316 long c, old, dec; 317 c = atomic64_read(v); 318 for (;;) { 319 dec = c - 1; 320 if (unlikely(dec < 0)) 321 break; 322 old = atomic64_cmpxchg((v), c, dec); 323 if (likely(old == c)) 324 break; 325 c = old; 326 } 327 return dec; 328 } 329 330 #endif /* !CONFIG_64BIT */ 331 332 333 #endif /* _ASM_PARISC_ATOMIC_H_ */ 334