include/asm-x86/local_64.h

   1 #ifndef _ARCH_X8664_LOCAL_H
   2 #define _ARCH_X8664_LOCAL_H
   3
   4 static inline void local_inc(local_t *l)
   5 {
   6         __asm__ __volatile__(
   7                 "incq %0"
   8                 :"+m" (l->a.counter));
   9 }
  10
  11 static inline void local_dec(local_t *l)
  12 {
  13         __asm__ __volatile__(
  14                 "decq %0"
  15                 :"+m" (l->a.counter));
  16 }
  17
  18 static inline void local_add(long i, local_t *l)
  19 {
  20         __asm__ __volatile__(
  21                 "addq %1,%0"
  22                 :"+m" (l->a.counter)
  23                 :"ir" (i));
  24 }
  25
  26 static inline void local_sub(long i, local_t *l)
  27 {
  28         __asm__ __volatile__(
  29                 "subq %1,%0"
  30                 :"+m" (l->a.counter)
  31                 :"ir" (i));
  32 }
  33
  34 /**
  35  * local_sub_and_test - subtract value from variable and test result
  36  * @i: integer value to subtract
  37  * @l: pointer to type local_t
  38  *
  39  * Atomically subtracts @i from @l and returns
  40  * true if the result is zero, or false for all
  41  * other cases.
  42  */
  43 static inline int local_sub_and_test(long i, local_t *l)
  44 {
  45         unsigned char c;
  46
  47         __asm__ __volatile__(
  48                 "subq %2,%0; sete %1"
  49                 :"+m" (l->a.counter), "=qm" (c)
  50                 :"ir" (i) : "memory");
  51         return c;
  52 }
  53
  54 /**
  55  * local_dec_and_test - decrement and test
  56  * @l: pointer to type local_t
  57  *
  58  * Atomically decrements @l by 1 and
  59  * returns true if the result is 0, or false for all other
  60  * cases.
  61  */
  62 static inline int local_dec_and_test(local_t *l)
  63 {
  64         unsigned char c;
  65
  66         __asm__ __volatile__(
  67                 "decq %0; sete %1"
  68                 :"+m" (l->a.counter), "=qm" (c)
  69                 : : "memory");
  70         return c != 0;
  71 }
  72
  73 /**
  74  * local_inc_and_test - increment and test
  75  * @l: pointer to type local_t
  76  *
  77  * Atomically increments @l by 1
  78  * and returns true if the result is zero, or false for all
  79  * other cases.
  80  */
  81 static inline int local_inc_and_test(local_t *l)
  82 {
  83         unsigned char c;
  84
  85         __asm__ __volatile__(
  86                 "incq %0; sete %1"
  87                 :"+m" (l->a.counter), "=qm" (c)
  88                 : : "memory");
  89         return c != 0;
  90 }
  91
  92 /**
  93  * local_add_negative - add and test if negative
  94  * @i: integer value to add
  95  * @l: pointer to type local_t
  96  *
  97  * Atomically adds @i to @l and returns true
  98  * if the result is negative, or false when
  99  * result is greater than or equal to zero.
 100  */
 101 static inline int local_add_negative(long i, local_t *l)
 102 {
 103         unsigned char c;
 104
 105         __asm__ __volatile__(
 106                 "addq %2,%0; sets %1"
 107                 :"+m" (l->a.counter), "=qm" (c)
 108                 :"ir" (i) : "memory");
 109         return c;
 110 }
 111
 112 /**
 113  * local_add_return - add and return
 114  * @i: integer value to add
 115  * @l: pointer to type local_t
 116  *
 117  * Atomically adds @i to @l and returns @i + @l
 118  */
 119 static inline long local_add_return(long i, local_t *l)
 120 {
 121         long __i = i;
 122         __asm__ __volatile__(
 123                 "xaddq %0, %1;"
 124                 :"+r" (i), "+m" (l->a.counter)
 125                 : : "memory");
 126         return i + __i;
 127 }
 128
 129 static inline long local_sub_return(long i, local_t *l)
 130 {
 131         return local_add_return(-i,l);
 132 }
 133
 134 #define local_inc_return(l)  (local_add_return(1,l))
 135 #define local_dec_return(l)  (local_sub_return(1,l))
 136
 137 #define local_cmpxchg(l, o, n) \
 138         (cmpxchg_local(&((l)->a.counter), (o), (n)))
 139 /* Always has a lock prefix */
 140 #define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
 141
 142 /**
 143  * atomic_up_add_unless - add unless the number is a given value
 144  * @l: pointer of type local_t
 145  * @a: the amount to add to l...
 146  * @u: ...unless l is equal to u.
 147  *
 148  * Atomically adds @a to @l, so long as it was not @u.
 149  * Returns non-zero if @l was not @u, and zero otherwise.
 150  */
 151 #define local_add_unless(l, a, u)                               \
 152 ({                                                              \
 153         long c, old;                                            \
 154         c = local_read(l);                                      \
 155         for (;;) {                                              \
 156                 if (unlikely(c == (u)))                         \
 157                         break;                                  \
 158                 old = local_cmpxchg((l), c, c + (a));   \
 159                 if (likely(old == c))                           \
 160                         break;                                  \
 161                 c = old;                                        \
 162         }                                                       \
 163         c != (u);                                               \
 164 })
 165 #define local_inc_not_zero(l) local_add_unless((l), 1, 0)
 166
 167 /* On x86-64 these are better than the atomic variants on SMP kernels
 168    because they dont use a lock prefix. */
 169 #define __local_inc(l)          local_inc(l)
 170 #define __local_dec(l)          local_dec(l)
 171 #define __local_add(i,l)        local_add((i),(l))
 172 #define __local_sub(i,l)        local_sub((i),(l))
 173
 174 /* Use these for per-cpu local_t variables: on some archs they are
 175  * much more efficient than these naive implementations.  Note they take
 176  * a variable, not an address.
 177  *
 178  * This could be done better if we moved the per cpu data directly
 179  * after GS.
 180  */
 181
 182 /* Need to disable preemption for the cpu local counters otherwise we could
 183    still access a variable of a previous CPU in a non atomic way. */
 184 #define cpu_local_wrap_v(l)             \
 185         ({ local_t res__;               \
 186            preempt_disable();           \
 187            res__ = (l);                 \
 188            preempt_enable();            \
 189            res__; })
 190 #define cpu_local_wrap(l)               \
 191         ({ preempt_disable();           \
 192            l;                           \
 193            preempt_enable(); })         \
 194
 195 #define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
 196 #define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
 197 #define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))
 198 #define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))
 199 #define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
 200 #define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
 201
 202 #define __cpu_local_inc(l)      cpu_local_inc(l)
 203 #define __cpu_local_dec(l)      cpu_local_dec(l)
 204 #define __cpu_local_add(i, l)   cpu_local_add((i), (l))
 205 #define __cpu_local_sub(i, l)   cpu_local_sub((i), (l))
 206
 207 #endif /* _ARCH_X8664_LOCAL_H */