#include "rtmutex_common.h"
+int __read_mostly futex_cmpxchg_enabled;
+
#define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8)
/*
*/
static void get_futex_key_refs(union futex_key *key)
{
- if (key->both.ptr == 0)
+ if (key->both.ptr == NULL)
return;
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
struct futex_hash_bucket *hb;
union futex_key key;
+ if (!futex_cmpxchg_enabled)
+ return;
/*
* We are a ZOMBIE and nobody can enqueue itself on
* pi_state_list anymore, but we have to be careful
if (!abs_time)
schedule();
else {
- hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
t.timer.expires = *abs_time;
- hrtimer_start(&t.timer, t.timer.expires, HRTIMER_MODE_ABS);
+ hrtimer_start(&t.timer, t.timer.expires,
+ HRTIMER_MODE_ABS);
if (!hrtimer_active(&t.timer))
t.task = NULL;
/* Flag if a timeout occured */
rem = (t.task == NULL);
+
+ destroy_hrtimer_on_stack(&t.timer);
}
}
__set_current_state(TASK_RUNNING);
if (time) {
to = &timeout;
- hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+ hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME,
+ HRTIMER_MODE_ABS);
hrtimer_init_sleeper(to, current);
to->timer.expires = *time;
}
unqueue_me_pi(&q);
futex_unlock_mm(fshared);
+ if (to)
+ destroy_hrtimer_on_stack(&to->timer);
return ret != -EINTR ? ret : -ERESTARTNOINTR;
out_unlock_release_sem:
out_release_sem:
futex_unlock_mm(fshared);
+ if (to)
+ destroy_hrtimer_on_stack(&to->timer);
return ret;
uaddr_faulted:
if (!ret && (uval != -EFAULT))
goto retry;
+ if (to)
+ destroy_hrtimer_on_stack(&to->timer);
return ret;
}
sys_set_robust_list(struct robust_list_head __user *head,
size_t len)
{
+ if (!futex_cmpxchg_enabled)
+ return -ENOSYS;
/*
* The kernel knows only one size for now:
*/
struct robust_list_head __user *head;
unsigned long ret;
+ if (!futex_cmpxchg_enabled)
+ return -ENOSYS;
+
if (!pid)
head = current->robust_list;
else {
unsigned long futex_offset;
int rc;
+ if (!futex_cmpxchg_enabled)
+ return;
+
/*
* Fetch the list head (which was registered earlier, via
* sys_set_robust_list()):
long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3)
{
- int ret;
+ int ret = -ENOSYS;
int cmd = op & FUTEX_CMD_MASK;
struct rw_semaphore *fshared = NULL;
ret = futex_wake_op(uaddr, fshared, uaddr2, val, val2, val3);
break;
case FUTEX_LOCK_PI:
- ret = futex_lock_pi(uaddr, fshared, val, timeout, 0);
+ if (futex_cmpxchg_enabled)
+ ret = futex_lock_pi(uaddr, fshared, val, timeout, 0);
break;
case FUTEX_UNLOCK_PI:
- ret = futex_unlock_pi(uaddr, fshared);
+ if (futex_cmpxchg_enabled)
+ ret = futex_unlock_pi(uaddr, fshared);
break;
case FUTEX_TRYLOCK_PI:
- ret = futex_lock_pi(uaddr, fshared, 0, timeout, 1);
+ if (futex_cmpxchg_enabled)
+ ret = futex_lock_pi(uaddr, fshared, 0, timeout, 1);
break;
default:
ret = -ENOSYS;
.kill_sb = kill_anon_super,
};
-static int __init init(void)
+static int __init futex_init(void)
{
- int i = register_filesystem(&futex_fs_type);
+ u32 curval;
+ int i;
+
+ /*
+ * This will fail and we want it. Some arch implementations do
+ * runtime detection of the futex_atomic_cmpxchg_inatomic()
+ * functionality. We want to know that before we call in any
+ * of the complex code paths. Also we want to prevent
+ * registration of robust lists in that case. NULL is
+ * guaranteed to fault and we get -EFAULT on functional
+ * implementation, the non functional ones will return
+ * -ENOSYS.
+ */
+ curval = cmpxchg_futex_value_locked(NULL, 0, 0);
+ if (curval == -EFAULT)
+ futex_cmpxchg_enabled = 1;
+
+ for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
+ plist_head_init(&futex_queues[i].chain, &futex_queues[i].lock);
+ spin_lock_init(&futex_queues[i].lock);
+ }
+ i = register_filesystem(&futex_fs_type);
if (i)
return i;
return PTR_ERR(futex_mnt);
}
- for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
- plist_head_init(&futex_queues[i].chain, &futex_queues[i].lock);
- spin_lock_init(&futex_queues[i].lock);
- }
return 0;
}
-__initcall(init);
+__initcall(futex_init);