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1275 |
phoenix |
#ifndef __ARCH_S390_ATOMIC__
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#define __ARCH_S390_ATOMIC__
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/*
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* include/asm-s390x/atomic.h
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*
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* S390 version
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* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
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* Denis Joseph Barrow
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*
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* Derived from "include/asm-i386/bitops.h"
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* Copyright (C) 1992, Linus Torvalds
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*
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*/
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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* S390 uses 'Compare And Swap' for atomicity in SMP enviroment
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*/
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typedef struct { volatile int counter; } __attribute__ ((aligned (4))) atomic_t;
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#define ATOMIC_INIT(i) { (i) }
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#define atomic_eieio() __asm__ __volatile__ ("BCR 15,0")
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#define __CS_LOOP(old_val, new_val, ptr, op_val, op_string) \
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__asm__ __volatile__(" l %0,0(%2)\n" \
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"0: lr %1,%0\n" \
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op_string " %1,%3\n" \
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" cs %0,%1,0(%2)\n" \
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" jl 0b" \
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: "=&d" (old_val), "=&d" (new_val) \
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: "a" (ptr), "d" (op_val) : "cc" );
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#define atomic_read(v) ((v)->counter)
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#define atomic_set(v,i) (((v)->counter) = (i))
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static __inline__ void atomic_add(int i, atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, i, "ar");
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}
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static __inline__ int atomic_add_return (int i, atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, i, "ar");
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return new_val;
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}
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static __inline__ int atomic_add_negative(int i, atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, i, "ar");
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return new_val < 0;
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}
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static __inline__ void atomic_sub(int i, atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, i, "sr");
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}
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static __inline__ void atomic_inc(volatile atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, 1, "ar");
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}
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static __inline__ int atomic_inc_return(volatile atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, 1, "ar");
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return new_val;
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}
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static __inline__ int atomic_inc_and_test(volatile atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, 1, "ar");
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return new_val != 0;
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}
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static __inline__ void atomic_dec(volatile atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, 1, "sr");
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}
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static __inline__ int atomic_dec_return(volatile atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, 1, "sr");
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return new_val;
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}
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static __inline__ int atomic_dec_and_test(volatile atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, 1, "sr");
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return new_val == 0;
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}
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static __inline__ void atomic_clear_mask(unsigned long mask, atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, ~mask, "nr");
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}
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static __inline__ void atomic_set_mask(unsigned long mask, atomic_t *v)
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{
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int old_val, new_val;
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__CS_LOOP(old_val, new_val, v, mask, "or");
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}
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/*
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returns 0 if expected_oldval==value in *v ( swap was successful )
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returns 1 if unsuccessful.
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*/
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static __inline__ int
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atomic_compare_and_swap(int expected_oldval,int new_val,atomic_t *v)
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{
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int retval;
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__asm__ __volatile__(
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" lr 0,%2\n"
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" cs 0,%3,0(%1)\n"
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" ipm %0\n"
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" srl %0,28\n"
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"0:"
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: "=&d" (retval)
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: "a" (v), "d" (expected_oldval) , "d" (new_val)
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: "0", "cc");
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return retval;
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}
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/*
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Spin till *v = expected_oldval then swap with newval.
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*/
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static __inline__ void
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atomic_compare_and_swap_spin(int expected_oldval,int new_val,atomic_t *v)
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{
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__asm__ __volatile__(
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"0: lr 0,%1\n"
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" cs 0,%2,0(%0)\n"
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" jl 0b\n"
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: : "a" (v), "d" (expected_oldval) , "d" (new_val)
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: "cc", "0" );
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}
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#define atomic_compare_and_swap_debug(where,from,to) \
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if (atomic_compare_and_swap ((from), (to), (where))) {\
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printk (KERN_WARNING"%s/%d atomic counter:%s couldn't be changed from %d(%s) to %d(%s), was %d\n",\
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__FILE__,__LINE__,#where,(from),#from,(to),#to,atomic_read (where));\
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atomic_set(where,(to));\
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}
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#define smp_mb__before_atomic_dec() smp_mb()
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#define smp_mb__after_atomic_dec() smp_mb()
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#define smp_mb__before_atomic_inc() smp_mb()
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#define smp_mb__after_atomic_inc() smp_mb()
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#endif /* __ARCH_S390_ATOMIC __ */
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