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atomic.h

#ifndef __ARCH_S390_ATOMIC__
#define __ARCH_S390_ATOMIC__

#include <linux/compiler.h>

/*
 *  include/asm-s390/atomic.h
 *
 *  S390 version
 *    Copyright (C) 1999-2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *               Denis Joseph Barrow,
 *           Arnd Bergmann (arndb@de.ibm.com)
 *
 *  Derived from "include/asm-i386/bitops.h"
 *    Copyright (C) 1992, Linus Torvalds
 *
 */

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 * S390 uses 'Compare And Swap' for atomicity in SMP enviroment
 */

typedef struct {
      int counter;
} __attribute__ ((aligned (4))) atomic_t;
#define ATOMIC_INIT(i)  { (i) }

#ifdef __KERNEL__

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)

#define __CS_LOOP(ptr, op_val, op_string) ({                      \
      typeof(ptr->counter) old_val, new_val;                      \
      asm volatile(                                         \
            "     l     %0,%2\n"                      \
            "0:   lr    %1,%0\n"                      \
            op_string " %1,%3\n"                      \
            "     cs    %0,%1,%2\n"                   \
            "     jl    0b"                           \
            : "=&d" (old_val), "=&d" (new_val),             \
              "=Q" (((atomic_t *)(ptr))->counter)                 \
            : "d" (op_val),    "Q" (((atomic_t *)(ptr))->counter) \
            : "cc", "memory");                              \
      new_val;                                        \
})

#else /* __GNUC__ */

#define __CS_LOOP(ptr, op_val, op_string) ({                      \
      typeof(ptr->counter) old_val, new_val;                      \
      asm volatile(                                         \
            "     l     %0,0(%3)\n"                   \
            "0:   lr    %1,%0\n"                      \
            op_string " %1,%4\n"                      \
            "     cs    %0,%1,0(%3)\n"                      \
            "     jl    0b"                           \
            : "=&d" (old_val), "=&d" (new_val),             \
              "=m" (((atomic_t *)(ptr))->counter)                 \
            : "a" (ptr), "d" (op_val),                      \
              "m" (((atomic_t *)(ptr))->counter)                  \
            : "cc", "memory");                              \
      new_val;                                        \
})

#endif /* __GNUC__ */

static inline int atomic_read(const atomic_t *v)
{
      barrier();
      return v->counter;
}

static inline void atomic_set(atomic_t *v, int i)
{
      v->counter = i;
      barrier();
}

static __inline__ int atomic_add_return(int i, atomic_t * v)
{
      return __CS_LOOP(v, i, "ar");
}
#define atomic_add(_i, _v)          atomic_add_return(_i, _v)
#define atomic_add_negative(_i, _v) (atomic_add_return(_i, _v) < 0)
#define atomic_inc(_v)              atomic_add_return(1, _v)
#define atomic_inc_return(_v)       atomic_add_return(1, _v)
#define atomic_inc_and_test(_v)           (atomic_add_return(1, _v) == 0)

static __inline__ int atomic_sub_return(int i, atomic_t * v)
{
      return __CS_LOOP(v, i, "sr");
}
#define atomic_sub(_i, _v)          atomic_sub_return(_i, _v)
#define atomic_sub_and_test(_i, _v) (atomic_sub_return(_i, _v) == 0)
#define atomic_dec(_v)              atomic_sub_return(1, _v)
#define atomic_dec_return(_v)       atomic_sub_return(1, _v)
#define atomic_dec_and_test(_v)           (atomic_sub_return(1, _v) == 0)

static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t * v)
{
             __CS_LOOP(v, ~mask, "nr");
}

static __inline__ void atomic_set_mask(unsigned long mask, atomic_t * v)
{
             __CS_LOOP(v, mask, "or");
}

#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

static __inline__ int atomic_cmpxchg(atomic_t *v, int old, int new)
{
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
      asm volatile(
            "     cs    %0,%2,%1"
            : "+d" (old), "=Q" (v->counter)
            : "d" (new), "Q" (v->counter)
            : "cc", "memory");
#else /* __GNUC__ */
      asm volatile(
            "     cs    %0,%3,0(%2)"
            : "+d" (old), "=m" (v->counter)
            : "a" (v), "d" (new), "m" (v->counter)
            : "cc", "memory");
#endif /* __GNUC__ */
      return old;
}

static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
{
      int c, old;
      c = atomic_read(v);
      for (;;) {
            if (unlikely(c == u))
                  break;
            old = atomic_cmpxchg(v, c, c + a);
            if (likely(old == c))
                  break;
            c = old;
      }
      return c != u;
}

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

#undef __CS_LOOP

#ifdef __s390x__
typedef struct {
      long long counter;
} __attribute__ ((aligned (8))) atomic64_t;
#define ATOMIC64_INIT(i)  { (i) }

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)

#define __CSG_LOOP(ptr, op_val, op_string) ({                     \
      typeof(ptr->counter) old_val, new_val;                      \
      asm volatile(                                         \
            "     lg    %0,%2\n"                      \
            "0:   lgr   %1,%0\n"                      \
            op_string " %1,%3\n"                      \
            "     csg   %0,%1,%2\n"                   \
            "     jl    0b"                           \
            : "=&d" (old_val), "=&d" (new_val),             \
              "=Q" (((atomic_t *)(ptr))->counter)                 \
            : "d" (op_val),   "Q" (((atomic_t *)(ptr))->counter)  \
            : "cc", "memory" );                             \
      new_val;                                        \
})

#else /* __GNUC__ */

#define __CSG_LOOP(ptr, op_val, op_string) ({                     \
      typeof(ptr->counter) old_val, new_val;                      \
      asm volatile(                                         \
            "     lg    %0,0(%3)\n"                   \
            "0:   lgr   %1,%0\n"                      \
            op_string " %1,%4\n"                      \
            "     csg   %0,%1,0(%3)\n"                      \
            "     jl    0b"                           \
            : "=&d" (old_val), "=&d" (new_val),             \
              "=m" (((atomic_t *)(ptr))->counter)                 \
            : "a" (ptr), "d" (op_val),                      \
              "m" (((atomic_t *)(ptr))->counter)                  \
            : "cc", "memory" );                             \
      new_val;                                        \
})

#endif /* __GNUC__ */

static inline long long atomic64_read(const atomic64_t *v)
{
      barrier();
      return v->counter;
}

static inline void atomic64_set(atomic64_t *v, long long i)
{
      v->counter = i;
      barrier();
}

static __inline__ long long atomic64_add_return(long long i, atomic64_t * v)
{
      return __CSG_LOOP(v, i, "agr");
}
#define atomic64_add(_i, _v)        atomic64_add_return(_i, _v)
#define atomic64_add_negative(_i, _v)     (atomic64_add_return(_i, _v) < 0)
#define atomic64_inc(_v)            atomic64_add_return(1, _v)
#define atomic64_inc_return(_v)           atomic64_add_return(1, _v)
#define atomic64_inc_and_test(_v)   (atomic64_add_return(1, _v) == 0)

static __inline__ long long atomic64_sub_return(long long i, atomic64_t * v)
{
      return __CSG_LOOP(v, i, "sgr");
}
#define atomic64_sub(_i, _v)        atomic64_sub_return(_i, _v)
#define atomic64_sub_and_test(_i, _v)     (atomic64_sub_return(_i, _v) == 0)
#define atomic64_dec(_v)            atomic64_sub_return(1, _v)
#define atomic64_dec_return(_v)           atomic64_sub_return(1, _v)
#define atomic64_dec_and_test(_v)   (atomic64_sub_return(1, _v) == 0)

static __inline__ void atomic64_clear_mask(unsigned long mask, atomic64_t * v)
{
             __CSG_LOOP(v, ~mask, "ngr");
}

static __inline__ void atomic64_set_mask(unsigned long mask, atomic64_t * v)
{
             __CSG_LOOP(v, mask, "ogr");
}

#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

static __inline__ long long atomic64_cmpxchg(atomic64_t *v,
                                   long long old, long long new)
{
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
      asm volatile(
            "     csg   %0,%2,%1"
            : "+d" (old), "=Q" (v->counter)
            : "d" (new), "Q" (v->counter)
            : "cc", "memory");
#else /* __GNUC__ */
      asm volatile(
            "     csg   %0,%3,0(%2)"
            : "+d" (old), "=m" (v->counter)
            : "a" (v), "d" (new), "m" (v->counter)
            : "cc", "memory");
#endif /* __GNUC__ */
      return old;
}

static __inline__ int atomic64_add_unless(atomic64_t *v,
                                long long a, long long u)
{
      long long c, old;
      c = atomic64_read(v);
      for (;;) {
            if (unlikely(c == u))
                  break;
            old = atomic64_cmpxchg(v, c, c + a);
            if (likely(old == c))
                  break;
            c = old;
      }
      return c != u;
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)

#undef __CSG_LOOP
#endif

#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec()  smp_mb()
#define smp_mb__before_atomic_inc() smp_mb()
#define smp_mb__after_atomic_inc()  smp_mb()

#include <asm-generic/atomic.h>
#endif /* __KERNEL__ */
#endif /* __ARCH_S390_ATOMIC__  */

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