Revision 34f7145a63211eb7ecfcafa6c2a8db5646baf953 authored by Phil Edworthy on 24 August 2011, 10:43:59 UTC, committed by Paul Mundt on 29 August 2011, 06:32:10 UTC
This adds unaligned memory access support for the following instructions: mov.w @(disp,PC),Rn mov.l @(disp,PC),Rn These instructions are often used on SH2A toolchains. Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
1 parent 0710b91
dec_and_lock.c
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
/*
* This is an implementation of the notion of "decrement a
* reference count, and return locked if it decremented to zero".
*
* NOTE NOTE NOTE! This is _not_ equivalent to
*
* if (atomic_dec_and_test(&atomic)) {
* spin_lock(&lock);
* return 1;
* }
* return 0;
*
* because the spin-lock and the decrement must be
* "atomic".
*/
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
if (atomic_add_unless(atomic, -1, 1))
return 0;
/* Otherwise do it the slow way */
spin_lock(lock);
if (atomic_dec_and_test(atomic))
return 1;
spin_unlock(lock);
return 0;
}
EXPORT_SYMBOL(_atomic_dec_and_lock);
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