Mac Easy 2010 May/Mac Life Ubuntu.iso/casper/filesystem.squashfs/usr/src/linux-headers-2.6.28-15/arch/powerpc/include/asm/local.h

C/C++ Source or Header | 2008-12-24 | 4.7 KB | 201 lines

#ifndef _ARCH_POWERPC_LOCAL_H
#define _ARCH_POWERPC_LOCAL_H

#include <linux/percpu.h>
#include <asm/atomic.h>

typedef struct
{
    atomic_long_t a;
} local_t;

#define LOCAL_INIT(i)    { ATOMIC_LONG_INIT(i) }

#define local_read(l)    atomic_long_read(&(l)->a)
#define local_set(l,i)    atomic_long_set(&(l)->a, (i))

#define local_add(i,l)    atomic_long_add((i),(&(l)->a))
#define local_sub(i,l)    atomic_long_sub((i),(&(l)->a))
#define local_inc(l)    atomic_long_inc(&(l)->a)
#define local_dec(l)    atomic_long_dec(&(l)->a)

static __inline__ long local_add_return(long a, local_t *l)
{
    long t;

    __asm__ __volatile__(
"1:"    PPC_LLARX    "%0,0,%2        # local_add_return\n\
    add    %0,%1,%0\n"
    PPC405_ERR77(0,%2)
    PPC_STLCX    "%0,0,%2 \n\
    bne-    1b"
    : "=&r" (t)
    : "r" (a), "r" (&(l->a.counter))
    : "cc", "memory");

    return t;
}

#define local_add_negative(a, l)    (local_add_return((a), (l)) < 0)

static __inline__ long local_sub_return(long a, local_t *l)
{
    long t;

    __asm__ __volatile__(
"1:"    PPC_LLARX    "%0,0,%2        # local_sub_return\n\
    subf    %0,%1,%0\n"
    PPC405_ERR77(0,%2)
    PPC_STLCX    "%0,0,%2 \n\
    bne-    1b"
    : "=&r" (t)
    : "r" (a), "r" (&(l->a.counter))
    : "cc", "memory");

    return t;
}

static __inline__ long local_inc_return(local_t *l)
{
    long t;

    __asm__ __volatile__(
"1:"    PPC_LLARX    "%0,0,%1        # local_inc_return\n\
    addic    %0,%0,1\n"
    PPC405_ERR77(0,%1)
    PPC_STLCX    "%0,0,%1 \n\
    bne-    1b"
    : "=&r" (t)
    : "r" (&(l->a.counter))
    : "cc", "memory");

    return t;
}

/*
 * local_inc_and_test - increment and test
 * @l: pointer of type local_t
 *
 * Atomically increments @l by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
#define local_inc_and_test(l) (local_inc_return(l) == 0)

static __inline__ long local_dec_return(local_t *l)
{
    long t;

    __asm__ __volatile__(
"1:"    PPC_LLARX    "%0,0,%1        # local_dec_return\n\
    addic    %0,%0,-1\n"
    PPC405_ERR77(0,%1)
    PPC_STLCX    "%0,0,%1\n\
    bne-    1b"
    : "=&r" (t)
    : "r" (&(l->a.counter))
    : "cc", "memory");

    return t;
}

#define local_cmpxchg(l, o, n) \
    (cmpxchg_local(&((l)->a.counter), (o), (n)))
#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))

/**
 * local_add_unless - add unless the number is a given value
 * @l: pointer of type local_t
 * @a: the amount to add to v...
 * @u: ...unless v is equal to u.
 *
 * Atomically adds @a to @l, so long as it was not @u.
 * Returns non-zero if @l was not @u, and zero otherwise.
 */
static __inline__ int local_add_unless(local_t *l, long a, long u)
{
    long t;

    __asm__ __volatile__ (
"1:"    PPC_LLARX    "%0,0,%1        # local_add_unless\n\
    cmpw    0,%0,%3 \n\
    beq-    2f \n\
    add    %0,%2,%0 \n"
    PPC405_ERR77(0,%2)
    PPC_STLCX    "%0,0,%1 \n\
    bne-    1b \n"
"    subf    %0,%2,%0 \n\
2:"
    : "=&r" (t)
    : "r" (&(l->a.counter)), "r" (a), "r" (u)
    : "cc", "memory");

    return t != u;
}

#define local_inc_not_zero(l) local_add_unless((l), 1, 0)

#define local_sub_and_test(a, l)    (local_sub_return((a), (l)) == 0)
#define local_dec_and_test(l)        (local_dec_return((l)) == 0)

/*
 * Atomically test *l and decrement if it is greater than 0.
 * The function returns the old value of *l minus 1.
 */
static __inline__ long local_dec_if_positive(local_t *l)
{
    long t;

    __asm__ __volatile__(
"1:"    PPC_LLARX    "%0,0,%1        # local_dec_if_positive\n\
    cmpwi    %0,1\n\
    addi    %0,%0,-1\n\
    blt-    2f\n"
    PPC405_ERR77(0,%1)
    PPC_STLCX    "%0,0,%1\n\
    bne-    1b"
    "\n\
2:"    : "=&b" (t)
    : "r" (&(l->a.counter))
    : "cc", "memory");

    return t;
}

/* Use these for per-cpu local_t variables: on some archs they are
 * much more efficient than these naive implementations.  Note they take
 * a variable, not an address.
 */

#define __local_inc(l)        ((l)->a.counter++)
#define __local_dec(l)        ((l)->a.counter++)
#define __local_add(i,l)    ((l)->a.counter+=(i))
#define __local_sub(i,l)    ((l)->a.counter-=(i))

/* Need to disable preemption for the cpu local counters otherwise we could
   still access a variable of a previous CPU in a non atomic way. */
#define cpu_local_wrap_v(l)         \
    ({ local_t res__;        \
       preempt_disable();         \
       res__ = (l);            \
       preempt_enable();        \
       res__; })
#define cpu_local_wrap(l)        \
    ({ preempt_disable();        \
       l;                \
       preempt_enable(); })        \

#define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))
#define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))
#define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))
#define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))
#define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))
#define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))

#define __cpu_local_inc(l)    cpu_local_inc(l)
#define __cpu_local_dec(l)    cpu_local_dec(l)
#define __cpu_local_add(i, l)    cpu_local_add((i), (l))
#define __cpu_local_sub(i, l)    cpu_local_sub((i), (l))

#endif /* _ARCH_POWERPC_LOCAL_H */