#include <linux/syscalls.h>
#include <linux/signal.h>
#include <linux/module.h>
+#include <linux/magic.h>
+#include <linux/pid.h>
+#include <linux/nsproxy.h>
+
#include <asm/futex.h>
#include "rtmutex_common.h"
+int __read_mostly futex_cmpxchg_enabled;
+
#define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8)
/*
/* Key which the futex is hashed on: */
union futex_key key;
- /* For fd, sigio sent using these: */
- int fd;
- struct file *filp;
-
/* Optional priority inheritance state: */
struct futex_pi_state *pi_state;
struct task_struct *task;
+
+ /* Bitset for the optional bitmasked wakeup */
+ u32 bitset;
};
/*
static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
-/* Futex-fs vfsmount entry: */
-static struct vfsmount *futex_mnt;
-
/*
* Take mm->mmap_sem, when futex is shared
*/
* For other futexes, it points to ¤t->mm->mmap_sem and
* caller must have taken the reader lock. but NOT any spinlocks.
*/
-int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared,
- union futex_key *key)
+static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared,
+ union futex_key *key)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
}
return err;
}
-EXPORT_SYMBOL_GPL(get_futex_key);
/*
* Take a reference to the resource addressed by a key.
* Can be called while holding spinlocks.
*
*/
-inline void get_futex_key_refs(union futex_key *key)
+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:
break;
}
}
-EXPORT_SYMBOL_GPL(get_futex_key_refs);
/*
* Drop a reference to the resource addressed by a key.
* The hash bucket spinlock must not be held.
*/
-void drop_futex_key_refs(union futex_key *key)
+static void drop_futex_key_refs(union futex_key *key)
{
- if (key->both.ptr == 0)
+ if (!key->both.ptr)
return;
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
break;
}
}
-EXPORT_SYMBOL_GPL(drop_futex_key_refs);
static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)
{
struct task_struct *p;
rcu_read_lock();
- p = find_task_by_pid(pid);
-
+ p = find_task_by_vpid(pid);
if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
p = ERR_PTR(-ESRCH);
else
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
static void wake_futex(struct futex_q *q)
{
plist_del(&q->list, &q->list.plist);
- if (q->filp)
- send_sigio(&q->filp->f_owner, q->fd, POLL_IN);
/*
* The lock in wake_up_all() is a crucial memory barrier after the
* plist_del() and also before assigning to q->lock_ptr.
if (!(uval & FUTEX_OWNER_DIED)) {
int ret = 0;
- newval = FUTEX_WAITERS | new_owner->pid;
+ newval = FUTEX_WAITERS | task_pid_vnr(new_owner);
curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
if (curval == -EFAULT)
ret = -EFAULT;
- if (curval != uval)
+ else if (curval != uval)
ret = -EINVAL;
if (ret) {
spin_unlock(&pi_state->pi_mutex.wait_lock);
* to this virtual address:
*/
static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
- int nr_wake)
+ int nr_wake, u32 bitset)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
union futex_key key;
int ret;
+ if (!bitset)
+ return -EINVAL;
+
futex_lock_mm(fshared);
ret = get_futex_key(uaddr, fshared, &key);
ret = -EINVAL;
break;
}
+
+ /* Check if one of the bits is set in both bitsets */
+ if (!(this->bitset & bitset))
+ continue;
+
wake_futex(this);
if (++ret >= nr_wake)
break;
}
/* The key must be already stored in q->key. */
-static inline struct futex_hash_bucket *
-queue_lock(struct futex_q *q, int fd, struct file *filp)
+static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)
{
struct futex_hash_bucket *hb;
- q->fd = fd;
- q->filp = filp;
-
init_waitqueue_head(&q->waiters);
get_futex_key_refs(&q->key);
return hb;
}
-static inline void __queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
+static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
{
int prio;
* exactly once. They are called with the hashed spinlock held.
*/
-/* The key must be already stored in q->key. */
-static void queue_me(struct futex_q *q, int fd, struct file *filp)
-{
- struct futex_hash_bucket *hb;
-
- hb = queue_lock(q, fd, filp);
- __queue_me(q, hb);
-}
-
/* Return 1 if we were still queued (ie. 0 means we were woken) */
static int unqueue_me(struct futex_q *q)
{
retry:
lock_ptr = q->lock_ptr;
barrier();
- if (lock_ptr != 0) {
+ if (lock_ptr != NULL) {
spin_lock(lock_ptr);
/*
* q->lock_ptr can change between reading it and
}
/*
- * Fixup the pi_state owner with current.
+ * Fixup the pi_state owner with the new owner.
*
* Must be called with hash bucket lock held and mm->sem held for non
* private futexes.
*/
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
- struct task_struct *curr)
+ struct task_struct *newowner,
+ struct rw_semaphore *fshared)
{
- u32 newtid = curr->pid | FUTEX_WAITERS;
+ u32 newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
struct futex_pi_state *pi_state = q->pi_state;
+ struct task_struct *oldowner = pi_state->owner;
u32 uval, curval, newval;
- int ret;
+ int ret, attempt = 0;
/* Owner died? */
- if (pi_state->owner != NULL) {
- spin_lock_irq(&pi_state->owner->pi_lock);
- WARN_ON(list_empty(&pi_state->list));
- list_del_init(&pi_state->list);
- spin_unlock_irq(&pi_state->owner->pi_lock);
- } else
+ if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;
- pi_state->owner = curr;
-
- spin_lock_irq(&curr->pi_lock);
- WARN_ON(!list_empty(&pi_state->list));
- list_add(&pi_state->list, &curr->pi_state_list);
- spin_unlock_irq(&curr->pi_lock);
-
/*
- * We own it, so we have to replace the pending owner
- * TID. This must be atomic as we have preserve the
- * owner died bit here.
+ * We are here either because we stole the rtmutex from the
+ * pending owner or we are the pending owner which failed to
+ * get the rtmutex. We have to replace the pending owner TID
+ * in the user space variable. This must be atomic as we have
+ * to preserve the owner died bit here.
+ *
+ * Note: We write the user space value _before_ changing the
+ * pi_state because we can fault here. Imagine swapped out
+ * pages or a fork, which was running right before we acquired
+ * mmap_sem, that marked all the anonymous memory readonly for
+ * cow.
+ *
+ * Modifying pi_state _before_ the user space value would
+ * leave the pi_state in an inconsistent state when we fault
+ * here, because we need to drop the hash bucket lock to
+ * handle the fault. This might be observed in the PID check
+ * in lookup_pi_state.
*/
- ret = get_futex_value_locked(&uval, uaddr);
+retry:
+ if (get_futex_value_locked(&uval, uaddr))
+ goto handle_fault;
- while (!ret) {
+ while (1) {
newval = (uval & FUTEX_OWNER_DIED) | newtid;
curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
if (curval == -EFAULT)
- ret = -EFAULT;
+ goto handle_fault;
if (curval == uval)
break;
uval = curval;
}
- return ret;
+
+ /*
+ * We fixed up user space. Now we need to fix the pi_state
+ * itself.
+ */
+ if (pi_state->owner != NULL) {
+ spin_lock_irq(&pi_state->owner->pi_lock);
+ WARN_ON(list_empty(&pi_state->list));
+ list_del_init(&pi_state->list);
+ spin_unlock_irq(&pi_state->owner->pi_lock);
+ }
+
+ pi_state->owner = newowner;
+
+ spin_lock_irq(&newowner->pi_lock);
+ WARN_ON(!list_empty(&pi_state->list));
+ list_add(&pi_state->list, &newowner->pi_state_list);
+ spin_unlock_irq(&newowner->pi_lock);
+ return 0;
+
+ /*
+ * To handle the page fault we need to drop the hash bucket
+ * lock here. That gives the other task (either the pending
+ * owner itself or the task which stole the rtmutex) the
+ * chance to try the fixup of the pi_state. So once we are
+ * back from handling the fault we need to check the pi_state
+ * after reacquiring the hash bucket lock and before trying to
+ * do another fixup. When the fixup has been done already we
+ * simply return.
+ */
+handle_fault:
+ spin_unlock(q->lock_ptr);
+
+ ret = futex_handle_fault((unsigned long)uaddr, fshared, attempt++);
+
+ spin_lock(q->lock_ptr);
+
+ /*
+ * Check if someone else fixed it for us:
+ */
+ if (pi_state->owner != oldowner)
+ return 0;
+
+ if (ret)
+ return ret;
+
+ goto retry;
}
/*
* In case we must use restart_block to restart a futex_wait,
- * we encode in the 'arg3' shared capability
+ * we encode in the 'flags' shared capability
*/
-#define ARG3_SHARED 1
+#define FLAGS_SHARED 1
static long futex_wait_restart(struct restart_block *restart);
static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
- u32 val, ktime_t *abs_time)
+ u32 val, ktime_t *abs_time, u32 bitset)
{
struct task_struct *curr = current;
DECLARE_WAITQUEUE(wait, curr);
struct hrtimer_sleeper t;
int rem = 0;
+ if (!bitset)
+ return -EINVAL;
+
q.pi_state = NULL;
+ q.bitset = bitset;
retry:
futex_lock_mm(fshared);
if (unlikely(ret != 0))
goto out_release_sem;
- hb = queue_lock(&q, -1, NULL);
+ hb = queue_lock(&q);
/*
* Access the page AFTER the futex is queued.
goto out_unlock_release_sem;
/* Only actually queue if *uaddr contained val. */
- __queue_me(&q, hb);
+ queue_me(&q, hb);
/*
* Now the futex is queued and we have checked the data, we
if (!abs_time)
schedule();
else {
- hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ unsigned long slack;
+ slack = current->timer_slack_ns;
+ if (rt_task(current))
+ slack = 0;
+ hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_ABS);
hrtimer_init_sleeper(&t, current);
- t.timer.expires = *abs_time;
+ hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
- hrtimer_start(&t.timer, t.timer.expires, HRTIMER_MODE_ABS);
+ hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
+ if (!hrtimer_active(&t.timer))
+ t.task = NULL;
/*
* the timer could have already expired, in which
/* Flag if a timeout occured */
rem = (t.task == NULL);
+
+ destroy_hrtimer_on_stack(&t.timer);
}
}
__set_current_state(TASK_RUNNING);
struct restart_block *restart;
restart = ¤t_thread_info()->restart_block;
restart->fn = futex_wait_restart;
- restart->arg0 = (unsigned long)uaddr;
- restart->arg1 = (unsigned long)val;
- restart->arg2 = (unsigned long)abs_time;
- restart->arg3 = 0;
+ restart->futex.uaddr = (u32 *)uaddr;
+ restart->futex.val = val;
+ restart->futex.time = abs_time->tv64;
+ restart->futex.bitset = bitset;
+ restart->futex.flags = 0;
+
if (fshared)
- restart->arg3 |= ARG3_SHARED;
+ restart->futex.flags |= FLAGS_SHARED;
return -ERESTART_RESTARTBLOCK;
}
static long futex_wait_restart(struct restart_block *restart)
{
- u32 __user *uaddr = (u32 __user *)restart->arg0;
- u32 val = (u32)restart->arg1;
- ktime_t *abs_time = (ktime_t *)restart->arg2;
+ u32 __user *uaddr = (u32 __user *)restart->futex.uaddr;
struct rw_semaphore *fshared = NULL;
+ ktime_t t;
+ t.tv64 = restart->futex.time;
restart->fn = do_no_restart_syscall;
- if (restart->arg3 & ARG3_SHARED)
+ if (restart->futex.flags & FLAGS_SHARED)
fshared = ¤t->mm->mmap_sem;
- return (long)futex_wait(uaddr, fshared, val, abs_time);
+ return (long)futex_wait(uaddr, fshared, restart->futex.val, &t,
+ restart->futex.bitset);
}
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;
+ hrtimer_set_expires(&to->timer, *time);
}
q.pi_state = NULL;
goto out_release_sem;
retry_unlocked:
- hb = queue_lock(&q, -1, NULL);
+ hb = queue_lock(&q);
retry_locked:
ret = lock_taken = 0;
* (by doing a 0 -> TID atomic cmpxchg), while holding all
* the locks. It will most likely not succeed.
*/
- newval = current->pid;
+ newval = task_pid_vnr(current);
curval = cmpxchg_futex_value_locked(uaddr, 0, newval);
* Detect deadlocks. In case of REQUEUE_PI this is a valid
* situation and we return success to user space.
*/
- if (unlikely((curval & FUTEX_TID_MASK) == current->pid)) {
+ if (unlikely((curval & FUTEX_TID_MASK) == task_pid_vnr(current))) {
ret = -EDEADLK;
goto out_unlock_release_sem;
}
*/
if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {
/* Keep the OWNER_DIED bit */
- newval = (curval & ~FUTEX_TID_MASK) | current->pid;
+ newval = (curval & ~FUTEX_TID_MASK) | task_pid_vnr(current);
ownerdied = 0;
lock_taken = 1;
}
/*
* Only actually queue now that the atomic ops are done:
*/
- __queue_me(&q, hb);
+ queue_me(&q, hb);
/*
* Now the futex is queued and we have checked the data, we
* that case:
*/
if (q.pi_state->owner != curr)
- ret = fixup_pi_state_owner(uaddr, &q, curr);
+ ret = fixup_pi_state_owner(uaddr, &q, curr, fshared);
} else {
/*
* Catch the rare case, where the lock was released
* when we were on the way back before we locked the
* hash bucket.
*/
- if (q.pi_state->owner == curr &&
- rt_mutex_trylock(&q.pi_state->pi_mutex)) {
- ret = 0;
+ if (q.pi_state->owner == curr) {
+ /*
+ * Try to get the rt_mutex now. This might
+ * fail as some other task acquired the
+ * rt_mutex after we removed ourself from the
+ * rt_mutex waiters list.
+ */
+ if (rt_mutex_trylock(&q.pi_state->pi_mutex))
+ ret = 0;
+ else {
+ /*
+ * pi_state is incorrect, some other
+ * task did a lock steal and we
+ * returned due to timeout or signal
+ * without taking the rt_mutex. Too
+ * late. We can access the
+ * rt_mutex_owner without locking, as
+ * the other task is now blocked on
+ * the hash bucket lock. Fix the state
+ * up.
+ */
+ struct task_struct *owner;
+ int res;
+
+ owner = rt_mutex_owner(&q.pi_state->pi_mutex);
+ res = fixup_pi_state_owner(uaddr, &q, owner,
+ fshared);
+
+ /* propagate -EFAULT, if the fixup failed */
+ if (res)
+ ret = res;
+ }
} else {
/*
* Paranoia check. If we did not take the lock
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;
}
/*
* We release only a lock we actually own:
*/
- if ((uval & FUTEX_TID_MASK) != current->pid)
+ if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current))
return -EPERM;
/*
* First take all the futex related locks:
* anyone else up:
*/
if (!(uval & FUTEX_OWNER_DIED))
- uval = cmpxchg_futex_value_locked(uaddr, current->pid, 0);
+ uval = cmpxchg_futex_value_locked(uaddr, task_pid_vnr(current), 0);
if (unlikely(uval == -EFAULT))
* Rare case: we managed to release the lock atomically,
* no need to wake anyone else up:
*/
- if (unlikely(uval == current->pid))
+ if (unlikely(uval == task_pid_vnr(current)))
goto out_unlock;
/*
return ret;
}
-static int futex_close(struct inode *inode, struct file *filp)
-{
- struct futex_q *q = filp->private_data;
-
- unqueue_me(q);
- kfree(q);
-
- return 0;
-}
-
-/* This is one-shot: once it's gone off you need a new fd */
-static unsigned int futex_poll(struct file *filp,
- struct poll_table_struct *wait)
-{
- struct futex_q *q = filp->private_data;
- int ret = 0;
-
- poll_wait(filp, &q->waiters, wait);
-
- /*
- * plist_node_empty() is safe here without any lock.
- * q->lock_ptr != 0 is not safe, because of ordering against wakeup.
- */
- if (plist_node_empty(&q->list))
- ret = POLLIN | POLLRDNORM;
-
- return ret;
-}
-
-static const struct file_operations futex_fops = {
- .release = futex_close,
- .poll = futex_poll,
-};
-
-/*
- * Signal allows caller to avoid the race which would occur if they
- * set the sigio stuff up afterwards.
- */
-static int futex_fd(u32 __user *uaddr, int signal)
-{
- struct futex_q *q;
- struct file *filp;
- int ret, err;
- struct rw_semaphore *fshared;
- static unsigned long printk_interval;
-
- if (printk_timed_ratelimit(&printk_interval, 60 * 60 * 1000)) {
- printk(KERN_WARNING "Process `%s' used FUTEX_FD, which "
- "will be removed from the kernel in June 2007\n",
- current->comm);
- }
-
- ret = -EINVAL;
- if (!valid_signal(signal))
- goto out;
-
- ret = get_unused_fd();
- if (ret < 0)
- goto out;
- filp = get_empty_filp();
- if (!filp) {
- put_unused_fd(ret);
- ret = -ENFILE;
- goto out;
- }
- filp->f_op = &futex_fops;
- filp->f_path.mnt = mntget(futex_mnt);
- filp->f_path.dentry = dget(futex_mnt->mnt_root);
- filp->f_mapping = filp->f_path.dentry->d_inode->i_mapping;
-
- if (signal) {
- err = __f_setown(filp, task_pid(current), PIDTYPE_PID, 1);
- if (err < 0) {
- goto error;
- }
- filp->f_owner.signum = signal;
- }
-
- q = kmalloc(sizeof(*q), GFP_KERNEL);
- if (!q) {
- err = -ENOMEM;
- goto error;
- }
- q->pi_state = NULL;
-
- fshared = ¤t->mm->mmap_sem;
- down_read(fshared);
- err = get_futex_key(uaddr, fshared, &q->key);
-
- if (unlikely(err != 0)) {
- up_read(fshared);
- kfree(q);
- goto error;
- }
-
- /*
- * queue_me() must be called before releasing mmap_sem, because
- * key->shared.inode needs to be referenced while holding it.
- */
- filp->private_data = q;
-
- queue_me(q, ret, filp);
- up_read(fshared);
-
- /* Now we map fd to filp, so userspace can access it */
- fd_install(ret, filp);
-out:
- return ret;
-error:
- put_unused_fd(ret);
- put_filp(filp);
- ret = err;
- goto out;
-}
-
/*
* Support for robust futexes: the kernel cleans up held futexes at
* thread exit time.
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 {
ret = -ESRCH;
rcu_read_lock();
- p = find_task_by_pid(pid);
+ p = find_task_by_vpid(pid);
if (!p)
goto err_unlock;
ret = -EPERM;
if (get_user(uval, uaddr))
return -1;
- if ((uval & FUTEX_TID_MASK) == curr->pid) {
+ if ((uval & FUTEX_TID_MASK) == task_pid_vnr(curr)) {
/*
* Ok, this dying thread is truly holding a futex
* of interest. Set the OWNER_DIED bit atomically
* PI futexes happens in exit_pi_state():
*/
if (!pi && (uval & FUTEX_WAITERS))
- futex_wake(uaddr, &curr->mm->mmap_sem, 1);
+ futex_wake(uaddr, &curr->mm->mmap_sem, 1,
+ FUTEX_BITSET_MATCH_ANY);
}
return 0;
}
void exit_robust_list(struct task_struct *curr)
{
struct robust_list_head __user *head = curr->robust_list;
- struct robust_list __user *entry, *pending;
- unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+ struct robust_list __user *entry, *next_entry, *pending;
+ unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
unsigned long futex_offset;
+ int rc;
+
+ if (!futex_cmpxchg_enabled)
+ return;
/*
* Fetch the list head (which was registered earlier, via
if (fetch_robust_entry(&pending, &head->list_op_pending, &pip))
return;
- if (pending)
- handle_futex_death((void __user *)pending + futex_offset,
- curr, pip);
-
+ next_entry = NULL; /* avoid warning with gcc */
while (entry != &head->list) {
/*
+ * Fetch the next entry in the list before calling
+ * handle_futex_death:
+ */
+ rc = fetch_robust_entry(&next_entry, &entry->next, &next_pi);
+ /*
* A pending lock might already be on the list, so
* don't process it twice:
*/
if (handle_futex_death((void __user *)entry + futex_offset,
curr, pi))
return;
- /*
- * Fetch the next entry in the list:
- */
- if (fetch_robust_entry(&entry, &entry->next, &pi))
+ if (rc)
return;
+ entry = next_entry;
+ pi = next_pi;
/*
* Avoid excessively long or circular lists:
*/
cond_resched();
}
+
+ if (pending)
+ handle_futex_death((void __user *)pending + futex_offset,
+ curr, pip);
}
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;
switch (cmd) {
case FUTEX_WAIT:
- ret = futex_wait(uaddr, fshared, val, timeout);
+ val3 = FUTEX_BITSET_MATCH_ANY;
+ case FUTEX_WAIT_BITSET:
+ ret = futex_wait(uaddr, fshared, val, timeout, val3);
break;
case FUTEX_WAKE:
- ret = futex_wake(uaddr, fshared, val);
- break;
- case FUTEX_FD:
- /* non-zero val means F_SETOWN(getpid()) & F_SETSIG(val) */
- ret = futex_fd(uaddr, val);
+ val3 = FUTEX_BITSET_MATCH_ANY;
+ case FUTEX_WAKE_BITSET:
+ ret = futex_wake(uaddr, fshared, val, val3);
break;
case FUTEX_REQUEUE:
ret = futex_requeue(uaddr, fshared, uaddr2, val, val2, 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;
u32 val2 = 0;
int cmd = op & FUTEX_CMD_MASK;
- if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI)) {
+ if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
+ cmd == FUTEX_WAIT_BITSET)) {
if (copy_from_user(&ts, utime, sizeof(ts)) != 0)
return -EFAULT;
if (!timespec_valid(&ts))
t = timespec_to_ktime(ts);
if (cmd == FUTEX_WAIT)
- t = ktime_add(ktime_get(), t);
+ t = ktime_add_safe(ktime_get(), t);
tp = &t;
}
/*
return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
}
-static int futexfs_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data,
- struct vfsmount *mnt)
-{
- return get_sb_pseudo(fs_type, "futex", NULL, 0xBAD1DEA, mnt);
-}
-
-static struct file_system_type futex_fs_type = {
- .name = "futexfs",
- .get_sb = futexfs_get_sb,
- .kill_sb = kill_anon_super,
-};
-
-static int __init init(void)
+static int __init futex_init(void)
{
- int i = register_filesystem(&futex_fs_type);
-
- if (i)
- return i;
+ u32 curval;
+ int i;
- futex_mnt = kern_mount(&futex_fs_type);
- if (IS_ERR(futex_mnt)) {
- unregister_filesystem(&futex_fs_type);
- return PTR_ERR(futex_mnt);
- }
+ /*
+ * 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);
}
+
return 0;
}
-__initcall(init);
+__initcall(futex_init);
projects / h-e-n / blobdiff