diff options
Diffstat (limited to 'kernel/arch/alpha/lib/dec_and_lock.c')
| -rw-r--r-- | kernel/arch/alpha/lib/dec_and_lock.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/kernel/arch/alpha/lib/dec_and_lock.c b/kernel/arch/alpha/lib/dec_and_lock.c new file mode 100644 index 000000000..f9f5fe830 --- /dev/null +++ b/kernel/arch/alpha/lib/dec_and_lock.c @@ -0,0 +1,41 @@ +/* + * arch/alpha/lib/dec_and_lock.c + * + * ll/sc version of atomic_dec_and_lock() + * + */ + +#include <linux/spinlock.h> +#include <linux/atomic.h> + + asm (".text \n\ + .global _atomic_dec_and_lock \n\ + .ent _atomic_dec_and_lock \n\ + .align 4 \n\ +_atomic_dec_and_lock: \n\ + .prologue 0 \n\ +1: ldl_l $1, 0($16) \n\ + subl $1, 1, $1 \n\ + beq $1, 2f \n\ + stl_c $1, 0($16) \n\ + beq $1, 4f \n\ + mb \n\ + clr $0 \n\ + ret \n\ +2: br $29, 3f \n\ +3: ldgp $29, 0($29) \n\ + br $atomic_dec_and_lock_1..ng \n\ + .subsection 2 \n\ +4: br 1b \n\ + .previous \n\ + .end _atomic_dec_and_lock"); + +static int __used atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock) +{ + /* Slow path */ + spin_lock(lock); + if (atomic_dec_and_test(atomic)) + return 1; + spin_unlock(lock); + return 0; +} |