arch/x86/include/asm/atomic64_64.h

   1 #ifndef _ASM_X86_ATOMIC64_64_H
   2 #define _ASM_X86_ATOMIC64_64_H
   3
   4 #include <linux/types.h>
   5 #include <asm/alternative.h>
   6 #include <asm/cmpxchg.h>
   7
   8 /* The 64-bit atomic type */
   9
  10 #define ATOMIC64_INIT(i)        { (i) }
  11
  12 /**
  13  * atomic64_read - read atomic64 variable
  14  * @v: pointer of type atomic64_t
  15  *
  16  * Atomically reads the value of @v.
  17  * Doesn't imply a read memory barrier.
  18  */
  19 static inline long atomic64_read(const atomic64_t *v)
  20 {
  21         return READ_ONCE((v)->counter);
  22 }
  23
  24 /**
  25  * atomic64_set - set atomic64 variable
  26  * @v: pointer to type atomic64_t
  27  * @i: required value
  28  *
  29  * Atomically sets the value of @v to @i.
  30  */
  31 static inline void atomic64_set(atomic64_t *v, long i)
  32 {
  33         WRITE_ONCE(v->counter, i);
  34 }
  35
  36 /**
  37  * atomic64_add - add integer to atomic64 variable
  38  * @i: integer value to add
  39  * @v: pointer to type atomic64_t
  40  *
  41  * Atomically adds @i to @v.
  42  */
  43 static __always_inline void atomic64_add(long i, atomic64_t *v)
  44 {
  45         asm volatile(LOCK_PREFIX "addq %1,%0"
  46                      : "=m" (v->counter)
  47                      : "er" (i), "m" (v->counter));
  48 }
  49
  50 /**
  51  * atomic64_sub - subtract the atomic64 variable
  52  * @i: integer value to subtract
  53  * @v: pointer to type atomic64_t
  54  *
  55  * Atomically subtracts @i from @v.
  56  */
  57 static inline void atomic64_sub(long i, atomic64_t *v)
  58 {
  59         asm volatile(LOCK_PREFIX "subq %1,%0"
  60                      : "=m" (v->counter)
  61                      : "er" (i), "m" (v->counter));
  62 }
  63
  64 /**
  65  * atomic64_sub_and_test - subtract value from variable and test result
  66  * @i: integer value to subtract
  67  * @v: pointer to type atomic64_t
  68  *
  69  * Atomically subtracts @i from @v and returns
  70  * true if the result is zero, or false for all
  71  * other cases.
  72  */
  73 static inline int atomic64_sub_and_test(long i, atomic64_t *v)
  74 {
  75         GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, "er", i, "%0", "e");
  76 }
  77
  78 /**
  79  * atomic64_inc - increment atomic64 variable
  80  * @v: pointer to type atomic64_t
  81  *
  82  * Atomically increments @v by 1.
  83  */
  84 static __always_inline void atomic64_inc(atomic64_t *v)
  85 {
  86         asm volatile(LOCK_PREFIX "incq %0"
  87                      : "=m" (v->counter)
  88                      : "m" (v->counter));
  89 }
  90
  91 /**
  92  * atomic64_dec - decrement atomic64 variable
  93  * @v: pointer to type atomic64_t
  94  *
  95  * Atomically decrements @v by 1.
  96  */
  97 static __always_inline void atomic64_dec(atomic64_t *v)
  98 {
  99         asm volatile(LOCK_PREFIX "decq %0"
 100                      : "=m" (v->counter)
 101                      : "m" (v->counter));
 102 }
 103
 104 /**
 105  * atomic64_dec_and_test - decrement and test
 106  * @v: pointer to type atomic64_t
 107  *
 108  * Atomically decrements @v by 1 and
 109  * returns true if the result is 0, or false for all other
 110  * cases.
 111  */
 112 static inline int atomic64_dec_and_test(atomic64_t *v)
 113 {
 114         GEN_UNARY_RMWcc(LOCK_PREFIX "decq", v->counter, "%0", "e");
 115 }
 116
 117 /**
 118  * atomic64_inc_and_test - increment and test
 119  * @v: pointer to type atomic64_t
 120  *
 121  * Atomically increments @v by 1
 122  * and returns true if the result is zero, or false for all
 123  * other cases.
 124  */
 125 static inline int atomic64_inc_and_test(atomic64_t *v)
 126 {
 127         GEN_UNARY_RMWcc(LOCK_PREFIX "incq", v->counter, "%0", "e");
 128 }
 129
 130 /**
 131  * atomic64_add_negative - add and test if negative
 132  * @i: integer value to add
 133  * @v: pointer to type atomic64_t
 134  *
 135  * Atomically adds @i to @v and returns true
 136  * if the result is negative, or false when
 137  * result is greater than or equal to zero.
 138  */
 139 static inline int atomic64_add_negative(long i, atomic64_t *v)
 140 {
 141         GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, "er", i, "%0", "s");
 142 }
 143
 144 /**
 145  * atomic64_add_return - add and return
 146  * @i: integer value to add
 147  * @v: pointer to type atomic64_t
 148  *
 149  * Atomically adds @i to @v and returns @i + @v
 150  */
 151 static __always_inline long atomic64_add_return(long i, atomic64_t *v)
 152 {
 153         return i + xadd(&v->counter, i);
 154 }
 155
 156 static inline long atomic64_sub_return(long i, atomic64_t *v)
 157 {
 158         return atomic64_add_return(-i, v);
 159 }
 160
 161 #define atomic64_inc_return(v)  (atomic64_add_return(1, (v)))
 162 #define atomic64_dec_return(v)  (atomic64_sub_return(1, (v)))
 163
 164 static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
 165 {
 166         return cmpxchg(&v->counter, old, new);
 167 }
 168
 169 static inline long atomic64_xchg(atomic64_t *v, long new)
 170 {
 171         return xchg(&v->counter, new);
 172 }
 173
 174 /**
 175  * atomic64_add_unless - add unless the number is a given value
 176  * @v: pointer of type atomic64_t
 177  * @a: the amount to add to v...
 178  * @u: ...unless v is equal to u.
 179  *
 180  * Atomically adds @a to @v, so long as it was not @u.
 181  * Returns the old value of @v.
 182  */
 183 static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
 184 {
 185         long c, old;
 186         c = atomic64_read(v);
 187         for (;;) {
 188                 if (unlikely(c == (u)))
 189                         break;
 190                 old = atomic64_cmpxchg((v), c, c + (a));
 191                 if (likely(old == c))
 192                         break;
 193                 c = old;
 194         }
 195         return c != (u);
 196 }
 197
 198 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 199
 200 /*
 201  * atomic64_dec_if_positive - decrement by 1 if old value positive
 202  * @v: pointer of type atomic_t
 203  *
 204  * The function returns the old value of *v minus 1, even if
 205  * the atomic variable, v, was not decremented.
 206  */
 207 static inline long atomic64_dec_if_positive(atomic64_t *v)
 208 {
 209         long c, old, dec;
 210         c = atomic64_read(v);
 211         for (;;) {
 212                 dec = c - 1;
 213                 if (unlikely(dec < 0))
 214                         break;
 215                 old = atomic64_cmpxchg((v), c, dec);
 216                 if (likely(old == c))
 217                         break;
 218                 c = old;
 219         }
 220         return dec;
 221 }
 222
 223 #define ATOMIC64_OP(op)                                                 \
 224 static inline void atomic64_##op(long i, atomic64_t *v)                 \
 225 {                                                                       \
 226         asm volatile(LOCK_PREFIX #op"q %1,%0"                           \
 227                         : "+m" (v->counter)                             \
 228                         : "er" (i)                                      \
 229                         : "memory");                                    \
 230 }
 231
 232 ATOMIC64_OP(and)
 233 ATOMIC64_OP(or)
 234 ATOMIC64_OP(xor)
 235
 236 #undef ATOMIC64_OP
 237
 238 #endif /* _ASM_X86_ATOMIC64_64_H */