arch/powerpc/include/asm/local.h

   1 #ifndef _ARCH_POWERPC_LOCAL_H
   2 #define _ARCH_POWERPC_LOCAL_H
   3
   4 #include <linux/percpu.h>
   5 #include <asm/atomic.h>
   6
   7 typedef struct
   8 {
   9         atomic_long_t a;
  10 } local_t;
  11
  12 #define LOCAL_INIT(i)   { ATOMIC_LONG_INIT(i) }
  13
  14 #define local_read(l)   atomic_long_read(&(l)->a)
  15 #define local_set(l,i)  atomic_long_set(&(l)->a, (i))
  16
  17 #define local_add(i,l)  atomic_long_add((i),(&(l)->a))
  18 #define local_sub(i,l)  atomic_long_sub((i),(&(l)->a))
  19 #define local_inc(l)    atomic_long_inc(&(l)->a)
  20 #define local_dec(l)    atomic_long_dec(&(l)->a)
  21
  22 static __inline__ long local_add_return(long a, local_t *l)
  23 {
  24         long t;
  25
  26         __asm__ __volatile__(
  27 "1:"    PPC_LLARX       "%0,0,%2                # local_add_return\n\
  28         add     %0,%1,%0\n"
  29         PPC405_ERR77(0,%2)
  30         PPC_STLCX       "%0,0,%2 \n\
  31         bne-    1b"
  32         : "=&r" (t)
  33         : "r" (a), "r" (&(l->a.counter))
  34         : "cc", "memory");
  35
  36         return t;
  37 }
  38
  39 #define local_add_negative(a, l)        (local_add_return((a), (l)) < 0)
  40
  41 static __inline__ long local_sub_return(long a, local_t *l)
  42 {
  43         long t;
  44
  45         __asm__ __volatile__(
  46 "1:"    PPC_LLARX       "%0,0,%2                # local_sub_return\n\
  47         subf    %0,%1,%0\n"
  48         PPC405_ERR77(0,%2)
  49         PPC_STLCX       "%0,0,%2 \n\
  50         bne-    1b"
  51         : "=&r" (t)
  52         : "r" (a), "r" (&(l->a.counter))
  53         : "cc", "memory");
  54
  55         return t;
  56 }
  57
  58 static __inline__ long local_inc_return(local_t *l)
  59 {
  60         long t;
  61
  62         __asm__ __volatile__(
  63 "1:"    PPC_LLARX       "%0,0,%1                # local_inc_return\n\
  64         addic   %0,%0,1\n"
  65         PPC405_ERR77(0,%1)
  66         PPC_STLCX       "%0,0,%1 \n\
  67         bne-    1b"
  68         : "=&r" (t)
  69         : "r" (&(l->a.counter))
  70         : "cc", "xer", "memory");
  71
  72         return t;
  73 }
  74
  75 /*
  76  * local_inc_and_test - increment and test
  77  * @l: pointer of type local_t
  78  *
  79  * Atomically increments @l by 1
  80  * and returns true if the result is zero, or false for all
  81  * other cases.
  82  */
  83 #define local_inc_and_test(l) (local_inc_return(l) == 0)
  84
  85 static __inline__ long local_dec_return(local_t *l)
  86 {
  87         long t;
  88
  89         __asm__ __volatile__(
  90 "1:"    PPC_LLARX       "%0,0,%1                # local_dec_return\n\
  91         addic   %0,%0,-1\n"
  92         PPC405_ERR77(0,%1)
  93         PPC_STLCX       "%0,0,%1\n\
  94         bne-    1b"
  95         : "=&r" (t)
  96         : "r" (&(l->a.counter))
  97         : "cc", "xer", "memory");
  98
  99         return t;
 100 }
 101
 102 #define local_cmpxchg(l, o, n) \
 103         (cmpxchg_local(&((l)->a.counter), (o), (n)))
 104 #define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
 105
 106 /**
 107  * local_add_unless - add unless the number is a given value
 108  * @l: pointer of type local_t
 109  * @a: the amount to add to v...
 110  * @u: ...unless v is equal to u.
 111  *
 112  * Atomically adds @a to @l, so long as it was not @u.
 113  * Returns non-zero if @l was not @u, and zero otherwise.
 114  */
 115 static __inline__ int local_add_unless(local_t *l, long a, long u)
 116 {
 117         long t;
 118
 119         __asm__ __volatile__ (
 120 "1:"    PPC_LLARX       "%0,0,%1                # local_add_unless\n\
 121         cmpw    0,%0,%3 \n\
 122         beq-    2f \n\
 123         add     %0,%2,%0 \n"
 124         PPC405_ERR77(0,%2)
 125         PPC_STLCX       "%0,0,%1 \n\
 126         bne-    1b \n"
 127 "       subf    %0,%2,%0 \n\
 128 2:"
 129         : "=&r" (t)
 130         : "r" (&(l->a.counter)), "r" (a), "r" (u)
 131         : "cc", "memory");
 132
 133         return t != u;
 134 }
 135
 136 #define local_inc_not_zero(l) local_add_unless((l), 1, 0)
 137
 138 #define local_sub_and_test(a, l)        (local_sub_return((a), (l)) == 0)
 139 #define local_dec_and_test(l)           (local_dec_return((l)) == 0)
 140
 141 /*
 142  * Atomically test *l and decrement if it is greater than 0.
 143  * The function returns the old value of *l minus 1.
 144  */
 145 static __inline__ long local_dec_if_positive(local_t *l)
 146 {
 147         long t;
 148
 149         __asm__ __volatile__(
 150 "1:"    PPC_LLARX       "%0,0,%1                # local_dec_if_positive\n\
 151         cmpwi   %0,1\n\
 152         addi    %0,%0,-1\n\
 153         blt-    2f\n"
 154         PPC405_ERR77(0,%1)
 155         PPC_STLCX       "%0,0,%1\n\
 156         bne-    1b"
 157         "\n\
 158 2:"     : "=&b" (t)
 159         : "r" (&(l->a.counter))
 160         : "cc", "memory");
 161
 162         return t;
 163 }
 164
 165 /* Use these for per-cpu local_t variables: on some archs they are
 166  * much more efficient than these naive implementations.  Note they take
 167  * a variable, not an address.
 168  */
 169
 170 #define __local_inc(l)          ((l)->a.counter++)
 171 #define __local_dec(l)          ((l)->a.counter++)
 172 #define __local_add(i,l)        ((l)->a.counter+=(i))
 173 #define __local_sub(i,l)        ((l)->a.counter-=(i))
 174
 175 /* Need to disable preemption for the cpu local counters otherwise we could
 176    still access a variable of a previous CPU in a non atomic way. */
 177 #define cpu_local_wrap_v(l)             \
 178         ({ local_t res__;               \
 179            preempt_disable();           \
 180            res__ = (l);                 \
 181            preempt_enable();            \
 182            res__; })
 183 #define cpu_local_wrap(l)               \
 184         ({ preempt_disable();           \
 185            l;                           \
 186            preempt_enable(); })         \
 187
 188 #define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
 189 #define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
 190 #define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))
 191 #define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))
 192 #define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
 193 #define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))
 194
 195 #define __cpu_local_inc(l)      cpu_local_inc(l)
 196 #define __cpu_local_dec(l)      cpu_local_dec(l)
 197 #define __cpu_local_add(i, l)   cpu_local_add((i), (l))
 198 #define __cpu_local_sub(i, l)   cpu_local_sub((i), (l))
 199
 200 #endif /* _ARCH_POWERPC_LOCAL_H */