arch/arc/include/asm/atomic.h

   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 #ifndef CONFIG_ARC_PLAT_EZNPS
  21
  22 #define atomic_read(v)  READ_ONCE((v)->counter)
  23
  24 #ifdef CONFIG_ARC_HAS_LLSC
  25
  26 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
  27
  28 #define ATOMIC_OP(op, c_op, asm_op)                                     \
  29 static inline void atomic_##op(int i, atomic_t *v)                      \
  30 {                                                                       \
  31         unsigned int val;                                               \
  32                                                                         \
  33         __asm__ __volatile__(                                           \
  34         "1:     llock   %[val], [%[ctr]]                \n"             \
  35         "       " #asm_op " %[val], %[val], %[i]        \n"             \
  36         "       scond   %[val], [%[ctr]]                \n"             \
  37         "       bnz     1b                              \n"             \
  38         : [val] "=&r"   (val) /* Early clobber to prevent reg reuse */  \
  39         : [ctr] "r"     (&v->counter), /* Not "m": llock only supports reg direct addr mode */  \
  40           [i]   "ir"    (i)                                             \
  41         : "cc");                                                        \
  42 }                                                                       \
  43
  44 #define ATOMIC_OP_RETURN(op, c_op, asm_op)                              \
  45 static inline int atomic_##op##_return(int i, atomic_t *v)              \
  46 {                                                                       \
  47         unsigned int val;                                               \
  48                                                                         \
  49         /*                                                              \
  50          * Explicit full memory barrier needed before/after as          \
  51          * LLOCK/SCOND thmeselves don't provide any such semantics      \
  52          */                                                             \
  53         smp_mb();                                                       \
  54                                                                         \
  55         __asm__ __volatile__(                                           \
  56         "1:     llock   %[val], [%[ctr]]                \n"             \
  57         "       " #asm_op " %[val], %[val], %[i]        \n"             \
  58         "       scond   %[val], [%[ctr]]                \n"             \
  59         "       bnz     1b                              \n"             \
  60         : [val] "=&r"   (val)                                           \
  61         : [ctr] "r"     (&v->counter),                                  \
  62           [i]   "ir"    (i)                                             \
  63         : "cc");                                                        \
  64                                                                         \
  65         smp_mb();                                                       \
  66                                                                         \
  67         return val;                                                     \
  68 }
  69
  70 #else   /* !CONFIG_ARC_HAS_LLSC */
  71
  72 #ifndef CONFIG_SMP
  73
  74  /* violating atomic_xxx API locking protocol in UP for optimization sake */
  75 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
  76
  77 #else
  78
  79 static inline void atomic_set(atomic_t *v, int i)
  80 {
  81         /*
  82          * Independent of hardware support, all of the atomic_xxx() APIs need
  83          * to follow the same locking rules to make sure that a "hardware"
  84          * atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn
  85          * sequence
  86          *
  87          * Thus atomic_set() despite being 1 insn (and seemingly atomic)
  88          * requires the locking.
  89          */
  90         unsigned long flags;
  91
  92         atomic_ops_lock(flags);
  93         WRITE_ONCE(v->counter, i);
  94         atomic_ops_unlock(flags);
  95 }
  96
  97 #endif
  98
  99 /*
 100  * Non hardware assisted Atomic-R-M-W
 101  * Locking would change to irq-disabling only (UP) and spinlocks (SMP)
 102  */
 103
 104 #define ATOMIC_OP(op, c_op, asm_op)                                     \
 105 static inline void atomic_##op(int i, atomic_t *v)                      \
 106 {                                                                       \
 107         unsigned long flags;                                            \
 108                                                                         \
 109         atomic_ops_lock(flags);                                         \
 110         v->counter c_op i;                                              \
 111         atomic_ops_unlock(flags);                                       \
 112 }
 113
 114 #define ATOMIC_OP_RETURN(op, c_op, asm_op)                              \
 115 static inline int atomic_##op##_return(int i, atomic_t *v)              \
 116 {                                                                       \
 117         unsigned long flags;                                            \
 118         unsigned long temp;                                             \
 119                                                                         \
 120         /*                                                              \
 121          * spin lock/unlock provides the needed smp_mb() before/after   \
 122          */                                                             \
 123         atomic_ops_lock(flags);                                         \
 124         temp = v->counter;                                              \
 125         temp c_op i;                                                    \
 126         v->counter = temp;                                              \
 127         atomic_ops_unlock(flags);                                       \
 128                                                                         \
 129         return temp;                                                    \
 130 }
 131
 132 #endif /* !CONFIG_ARC_HAS_LLSC */
 133
 134 #define ATOMIC_OPS(op, c_op, asm_op)                                    \
 135         ATOMIC_OP(op, c_op, asm_op)                                     \
 136         ATOMIC_OP_RETURN(op, c_op, asm_op)
 137
 138 ATOMIC_OPS(add, +=, add)
 139 ATOMIC_OPS(sub, -=, sub)
 140
 141 #define atomic_andnot atomic_andnot
 142
 143 ATOMIC_OP(and, &=, and)
 144 ATOMIC_OP(andnot, &= ~, bic)
 145 ATOMIC_OP(or, |=, or)
 146 ATOMIC_OP(xor, ^=, xor)
 147
 148 #undef SCOND_FAIL_RETRY_VAR_DEF
 149 #undef SCOND_FAIL_RETRY_ASM
 150 #undef SCOND_FAIL_RETRY_VARS
 151
 152 #else /* CONFIG_ARC_PLAT_EZNPS */
 153
 154 static inline int atomic_read(const atomic_t *v)
 155 {
 156         int temp;
 157
 158         __asm__ __volatile__(
 159         "       ld.di %0, [%1]"
 160         : "=r"(temp)
 161         : "r"(&v->counter)
 162         : "memory");
 163         return temp;
 164 }
 165
 166 static inline void atomic_set(atomic_t *v, int i)
 167 {
 168         __asm__ __volatile__(
 169         "       st.di %0,[%1]"
 170         :
 171         : "r"(i), "r"(&v->counter)
 172         : "memory");
 173 }
 174
 175 #define ATOMIC_OP(op, c_op, asm_op)                                     \
 176 static inline void atomic_##op(int i, atomic_t *v)                      \
 177 {                                                                       \
 178         __asm__ __volatile__(                                           \
 179         "       mov r2, %0\n"                                           \
 180         "       mov r3, %1\n"                                           \
 181         "       .word %2\n"                                             \
 182         :                                                               \
 183         : "r"(i), "r"(&v->counter), "i"(asm_op)                         \
 184         : "r2", "r3", "memory");                                        \
 185 }                                                                       \
 186
 187 #define ATOMIC_OP_RETURN(op, c_op, asm_op)                              \
 188 static inline int atomic_##op##_return(int i, atomic_t *v)              \
 189 {                                                                       \
 190         unsigned int temp = i;                                          \
 191                                                                         \
 192         /* Explicit full memory barrier needed before/after */          \
 193         smp_mb();                                                       \
 194                                                                         \
 195         __asm__ __volatile__(                                           \
 196         "       mov r2, %0\n"                                           \
 197         "       mov r3, %1\n"                                           \
 198         "       .word %2\n"                                             \
 199         "       mov %0, r2"                                             \
 200         : "+r"(temp)                                                    \
 201         : "r"(&v->counter), "i"(asm_op)                                 \
 202         : "r2", "r3", "memory");                                        \
 203                                                                         \
 204         smp_mb();                                                       \
 205                                                                         \
 206         temp c_op i;                                                    \
 207                                                                         \
 208         return temp;                                                    \
 209 }
 210
 211 #define ATOMIC_OPS(op, c_op, asm_op)                                    \
 212         ATOMIC_OP(op, c_op, asm_op)                                     \
 213         ATOMIC_OP_RETURN(op, c_op, asm_op)
 214
 215 ATOMIC_OPS(add, +=, CTOP_INST_AADD_DI_R2_R2_R3)
 216 #define atomic_sub(i, v) atomic_add(-(i), (v))
 217 #define atomic_sub_return(i, v) atomic_add_return(-(i), (v))
 218
 219 ATOMIC_OP(and, &=, CTOP_INST_AAND_DI_R2_R2_R3)
 220 #define atomic_andnot(mask, v) atomic_and(~(mask), (v))
 221 ATOMIC_OP(or, |=, CTOP_INST_AOR_DI_R2_R2_R3)
 222 ATOMIC_OP(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3)
 223
 224 #endif /* CONFIG_ARC_PLAT_EZNPS */
 225
 226 #undef ATOMIC_OPS
 227 #undef ATOMIC_OP_RETURN
 228 #undef ATOMIC_OP
 229
 230 /**
 231  * __atomic_add_unless - add unless the number is a given value
 232  * @v: pointer of type atomic_t
 233  * @a: the amount to add to v...
 234  * @u: ...unless v is equal to u.
 235  *
 236  * Atomically adds @a to @v, so long as it was not @u.
 237  * Returns the old value of @v
 238  */
 239 #define __atomic_add_unless(v, a, u)                                    \
 240 ({                                                                      \
 241         int c, old;                                                     \
 242                                                                         \
 243         /*                                                              \
 244          * Explicit full memory barrier needed before/after as          \
 245          * LLOCK/SCOND thmeselves don't provide any such semantics      \
 246          */                                                             \
 247         smp_mb();                                                       \
 248                                                                         \
 249         c = atomic_read(v);                                             \
 250         while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\
 251                 c = old;                                                \
 252                                                                         \
 253         smp_mb();                                                       \
 254                                                                         \
 255         c;                                                              \
 256 })
 257
 258 #define atomic_inc_not_zero(v)          atomic_add_unless((v), 1, 0)
 259
 260 #define atomic_inc(v)                   atomic_add(1, v)
 261 #define atomic_dec(v)                   atomic_sub(1, v)
 262
 263 #define atomic_inc_and_test(v)          (atomic_add_return(1, v) == 0)
 264 #define atomic_dec_and_test(v)          (atomic_sub_return(1, v) == 0)
 265 #define atomic_inc_return(v)            atomic_add_return(1, (v))
 266 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
 267 #define atomic_sub_and_test(i, v)       (atomic_sub_return(i, v) == 0)
 268
 269 #define atomic_add_negative(i, v)       (atomic_add_return(i, v) < 0)
 270
 271 #define ATOMIC_INIT(i)                  { (i) }
 272
 273 #include <asm-generic/atomic64.h>
 274
 275 #endif
 276
 277 #endif