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freebsd-skq/sys/kern/kern_umtx.c
David Xu ae7d8a6766 Implement 32bit umtx_lock and umtx_unlock system calls, these two system 
calls are not used by libthr in RELENG_6 and HEAD, it is only used by
the libthr in RELENG-5, the _umtx_op system call can do more incremental
dirty works than these two system calls without having to introduce new
system calls or throw away old system calls when things are going on.
2006-10-06 08:22:08 +00:00

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/*-
* Copyright (c) 2004, David Xu <davidxu@freebsd.org>
* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/eventhandler.h>
#include <sys/umtx.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#ifdef COMPAT_IA32
#include <compat/freebsd32/freebsd32_proto.h>
#endif
#define TYPE_SIMPLE_LOCK 0
#define TYPE_SIMPLE_WAIT 1
#define TYPE_NORMAL_UMUTEX 2
#define TYPE_PI_UMUTEX 3
#define TYPE_PP_UMUTEX 4
#define TYPE_CV 5
/* Key to represent a unique userland synchronous object */
struct umtx_key {
int hash;
int type;
int shared;
union {
struct {
vm_object_t object;
uintptr_t offset;
} shared;
struct {
struct vmspace *vs;
uintptr_t addr;
} private;
struct {
void *a;
uintptr_t b;
} both;
} info;
};
/* Priority inheritance mutex info. */
struct umtx_pi {
/* Owner thread */
struct thread *pi_owner;
/* Reference count */
int pi_refcount;
/* List entry to link umtx holding by thread */
TAILQ_ENTRY(umtx_pi) pi_link;
/* List entry in hash */
TAILQ_ENTRY(umtx_pi) pi_hashlink;
/* List for waiters */
TAILQ_HEAD(,umtx_q) pi_blocked;
/* Identify a userland lock object */
struct umtx_key pi_key;
};
/* A userland synchronous object user. */
struct umtx_q {
/* Linked list for the hash. */
TAILQ_ENTRY(umtx_q) uq_link;
/* Umtx key. */
struct umtx_key uq_key;
/* Umtx flags. */
int uq_flags;
#define UQF_UMTXQ 0x0001
/* The thread waits on. */
struct thread *uq_thread;
/*
* Blocked on PI mutex. read can use chain lock
* or sched_lock, write must have both chain lock and
* sched_lock being hold.
*/
struct umtx_pi *uq_pi_blocked;
/* On blocked list */
TAILQ_ENTRY(umtx_q) uq_lockq;
/* Thread contending with us */
TAILQ_HEAD(,umtx_pi) uq_pi_contested;
/* Inherited priority from PP mutex */
u_char uq_inherited_pri;
};
TAILQ_HEAD(umtxq_head, umtx_q);
/* Userland lock object's wait-queue chain */
struct umtxq_chain {
/* Lock for this chain. */
struct mtx uc_lock;
/* List of sleep queues. */
struct umtxq_head uc_queue;
/* Busy flag */
char uc_busy;
/* Chain lock waiters */
int uc_waiters;
/* All PI in the list */
TAILQ_HEAD(,umtx_pi) uc_pi_list;
};
#define UMTXQ_LOCKED_ASSERT(uc) mtx_assert(&(uc)->uc_lock, MA_OWNED)
/*
* Don't propagate time-sharing priority, there is a security reason,
* a user can simply introduce PI-mutex, let thread A lock the mutex,
* and let another thread B block on the mutex, because B is
* sleeping, its priority will be boosted, this causes A's priority to
* be boosted via priority propagating too and will never be lowered even
* if it is using 100%CPU, this is unfair to other processes.
*/
#define UPRI(td) (((td)->td_ksegrp->kg_user_pri >= PRI_MIN_TIMESHARE &&\
(td)->td_ksegrp->kg_user_pri <= PRI_MAX_TIMESHARE) ?\
PRI_MAX_TIMESHARE : (td)->td_ksegrp->kg_user_pri)
#define GOLDEN_RATIO_PRIME 2654404609U
#define UMTX_CHAINS 128
#define UMTX_SHIFTS (__WORD_BIT - 7)
#define THREAD_SHARE 0
#define PROCESS_SHARE 1
#define AUTO_SHARE 2
#define GET_SHARE(flags) \
(((flags) & USYNC_PROCESS_SHARED) == 0 ? THREAD_SHARE : PROCESS_SHARE)
static uma_zone_t umtx_pi_zone;
static struct umtxq_chain umtxq_chains[UMTX_CHAINS];
static MALLOC_DEFINE(M_UMTX, "umtx", "UMTX queue memory");
static int umtx_pi_allocated;
SYSCTL_NODE(_debug, OID_AUTO, umtx, CTLFLAG_RW, 0, "umtx debug");
SYSCTL_INT(_debug_umtx, OID_AUTO, umtx_pi_allocated, CTLFLAG_RD,
&umtx_pi_allocated, 0, "Allocated umtx_pi");
static void umtxq_sysinit(void *);
static void umtxq_hash(struct umtx_key *key);
static struct umtxq_chain *umtxq_getchain(struct umtx_key *key);
static void umtxq_lock(struct umtx_key *key);
static void umtxq_unlock(struct umtx_key *key);
static void umtxq_busy(struct umtx_key *key);
static void umtxq_unbusy(struct umtx_key *key);
static void umtxq_insert(struct umtx_q *uq);
static void umtxq_remove(struct umtx_q *uq);
static int umtxq_sleep(struct umtx_q *uq, const char *wmesg, int timo);
static int umtxq_count(struct umtx_key *key);
static int umtxq_signal(struct umtx_key *key, int nr_wakeup);
static int umtx_key_match(const struct umtx_key *k1, const struct umtx_key *k2);
static int umtx_key_get(void *addr, int type, int share,
struct umtx_key *key);
static void umtx_key_release(struct umtx_key *key);
static struct umtx_pi *umtx_pi_alloc(void);
static void umtx_pi_free(struct umtx_pi *pi);
static int do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags);
static void umtx_thread_cleanup(struct thread *td);
static void umtx_exec_hook(void *arg __unused, struct proc *p __unused,
struct image_params *imgp __unused);
SYSINIT(umtx, SI_SUB_EVENTHANDLER+1, SI_ORDER_MIDDLE, umtxq_sysinit, NULL);
static void
umtxq_sysinit(void *arg __unused)
{
int i;
umtx_pi_zone = uma_zcreate("umtx pi", sizeof(struct umtx_pi),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
for (i = 0; i < UMTX_CHAINS; ++i) {
mtx_init(&umtxq_chains[i].uc_lock, "umtxql", NULL,
MTX_DEF | MTX_DUPOK);
TAILQ_INIT(&umtxq_chains[i].uc_queue);
TAILQ_INIT(&umtxq_chains[i].uc_pi_list);
umtxq_chains[i].uc_busy = 0;
umtxq_chains[i].uc_waiters = 0;
}
EVENTHANDLER_REGISTER(process_exec, umtx_exec_hook, NULL,
EVENTHANDLER_PRI_ANY);
}
struct umtx_q *
umtxq_alloc(void)
{
struct umtx_q *uq;
uq = malloc(sizeof(struct umtx_q), M_UMTX, M_WAITOK | M_ZERO);
TAILQ_INIT(&uq->uq_pi_contested);
uq->uq_inherited_pri = PRI_MAX;
return (uq);
}
void
umtxq_free(struct umtx_q *uq)
{
free(uq, M_UMTX);
}
static inline void
umtxq_hash(struct umtx_key *key)
{
unsigned n = (uintptr_t)key->info.both.a + key->info.both.b;
key->hash = ((n * GOLDEN_RATIO_PRIME) >> UMTX_SHIFTS) % UMTX_CHAINS;
}
static inline int
umtx_key_match(const struct umtx_key *k1, const struct umtx_key *k2)
{
return (k1->type == k2->type &&
k1->info.both.a == k2->info.both.a &&
k1->info.both.b == k2->info.both.b);
}
static inline struct umtxq_chain *
umtxq_getchain(struct umtx_key *key)
{
return (&umtxq_chains[key->hash]);
}
/*
* Set chain to busy state when following operation
* may be blocked (kernel mutex can not be used).
*/
static inline void
umtxq_busy(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_assert(&uc->uc_lock, MA_OWNED);
while (uc->uc_busy != 0) {
uc->uc_waiters++;
msleep(uc, &uc->uc_lock, 0, "umtxqb", 0);
uc->uc_waiters--;
}
uc->uc_busy = 1;
}
/*
* Unbusy a chain.
*/
static inline void
umtxq_unbusy(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_assert(&uc->uc_lock, MA_OWNED);
KASSERT(uc->uc_busy != 0, ("not busy"));
uc->uc_busy = 0;
if (uc->uc_waiters)
wakeup_one(uc);
}
/*
* Lock a chain.
*/
static inline void
umtxq_lock(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_lock(&uc->uc_lock);
}
/*
* Unlock a chain.
*/
static inline void
umtxq_unlock(struct umtx_key *key)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(key);
mtx_unlock(&uc->uc_lock);
}
/*
* Insert a thread onto the umtx queue.
*/
static inline void
umtxq_insert(struct umtx_q *uq)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_INSERT_TAIL(&uc->uc_queue, uq, uq_link);
uq->uq_flags |= UQF_UMTXQ;
}
/*
* Remove thread from the umtx queue.
*/
static inline void
umtxq_remove(struct umtx_q *uq)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
if (uq->uq_flags & UQF_UMTXQ) {
TAILQ_REMOVE(&uc->uc_queue, uq, uq_link);
uq->uq_flags &= ~UQF_UMTXQ;
}
}
/*
* Check if there are multiple waiters
*/
static int
umtxq_count(struct umtx_key *key)
{
struct umtxq_chain *uc;
struct umtx_q *uq;
int count = 0;
uc = umtxq_getchain(key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_FOREACH(uq, &uc->uc_queue, uq_link) {
if (umtx_key_match(&uq->uq_key, key)) {
if (++count > 1)
break;
}
}
return (count);
}
/*
* Check if there are multiple PI waiters and returns first
* waiter.
*/
static int
umtxq_count_pi(struct umtx_key *key, struct umtx_q **first)
{
struct umtxq_chain *uc;
struct umtx_q *uq;
int count = 0;
*first = NULL;
uc = umtxq_getchain(key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_FOREACH(uq, &uc->uc_queue, uq_link) {
if (umtx_key_match(&uq->uq_key, key)) {
if (++count > 1)
break;
*first = uq;
}
}
return (count);
}
/*
* Wake up threads waiting on an userland object.
*/
static int
umtxq_signal(struct umtx_key *key, int n_wake)
{
struct umtxq_chain *uc;
struct umtx_q *uq, *next;
int ret;
ret = 0;
uc = umtxq_getchain(key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_FOREACH_SAFE(uq, &uc->uc_queue, uq_link, next) {
if (umtx_key_match(&uq->uq_key, key)) {
umtxq_remove(uq);
wakeup(uq);
if (++ret >= n_wake)
break;
}
}
return (ret);
}
/*
* Wake up specified thread.
*/
static inline void
umtxq_signal_thread(struct umtx_q *uq)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
umtxq_remove(uq);
wakeup(uq);
}
/*
* Put thread into sleep state, before sleeping, check if
* thread was removed from umtx queue.
*/
static inline int
umtxq_sleep(struct umtx_q *uq, const char *wmesg, int timo)
{
struct umtxq_chain *uc;
int error;
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
if (!(uq->uq_flags & UQF_UMTXQ))
return (0);
error = msleep(uq, &uc->uc_lock, PCATCH, wmesg, timo);
if (error == EWOULDBLOCK)
error = ETIMEDOUT;
return (error);
}
/*
* Convert userspace address into unique logical address.
*/
static int
umtx_key_get(void *addr, int type, int share, struct umtx_key *key)
{
struct thread *td = curthread;
vm_map_t map;
vm_map_entry_t entry;
vm_pindex_t pindex;
vm_prot_t prot;
boolean_t wired;
key->type = type;
if (share == THREAD_SHARE) {
key->shared = 0;
key->info.private.vs = td->td_proc->p_vmspace;
key->info.private.addr = (uintptr_t)addr;
} else if (share == PROCESS_SHARE || share == AUTO_SHARE) {
map = &td->td_proc->p_vmspace->vm_map;
if (vm_map_lookup(&map, (vm_offset_t)addr, VM_PROT_WRITE,
&entry, &key->info.shared.object, &pindex, &prot,
&wired) != KERN_SUCCESS) {
return EFAULT;
}
if ((share == PROCESS_SHARE) ||
(share == AUTO_SHARE &&
VM_INHERIT_SHARE == entry->inheritance)) {
key->shared = 1;
key->info.shared.offset = entry->offset + entry->start -
(vm_offset_t)addr;
vm_object_reference(key->info.shared.object);
} else {
key->shared = 0;
key->info.private.vs = td->td_proc->p_vmspace;
key->info.private.addr = (uintptr_t)addr;
}
vm_map_lookup_done(map, entry);
}
umtxq_hash(key);
return (0);
}
/*
* Release key.
*/
static inline void
umtx_key_release(struct umtx_key *key)
{
if (key->shared)
vm_object_deallocate(key->info.shared.object);
}
/*
* Lock a umtx object.
*/
static int
_do_lock_umtx(struct thread *td, struct umtx *umtx, uintptr_t id, int timo)
{
struct umtx_q *uq;
intptr_t owner;
intptr_t old;
int error = 0;
uq = td->td_umtxq;
/*
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
for (;;) {
/*
* Try the uncontested case. This should be done in userland.
*/
owner = casuptr((intptr_t *)&umtx->u_owner, UMTX_UNOWNED, id);
/* The acquire succeeded. */
if (owner == UMTX_UNOWNED)
return (0);
/* The address was invalid. */
if (owner == -1)
return (EFAULT);
/* If no one owns it but it is contested try to acquire it. */
if (owner == UMTX_CONTESTED) {
owner = casuptr((intptr_t *)&umtx->u_owner,
UMTX_CONTESTED, id | UMTX_CONTESTED);
if (owner == UMTX_CONTESTED)
return (0);
/* The address was invalid. */
if (owner == -1)
return (EFAULT);
/* If this failed the lock has changed, restart. */
continue;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
return (error);
if ((error = umtx_key_get(umtx, TYPE_SIMPLE_LOCK,
AUTO_SHARE, &uq->uq_key)) != 0)
return (error);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
* either some one else has acquired the lock or it has been
* released.
*/
old = casuptr((intptr_t *)&umtx->u_owner, owner,
owner | UMTX_CONTESTED);
/* The address was invalid. */
if (old == -1) {
umtxq_lock(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(&uq->uq_key);
if (old == owner)
error = umtxq_sleep(uq, "umtx", timo);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
}
return (0);
}
/*
* Lock a umtx object.
*/
static int
do_lock_umtx(struct thread *td, struct umtx *umtx, uintptr_t id,
struct timespec *timeout)
{
struct timespec ts, ts2, ts3;
struct timeval tv;
int error;
if (timeout == NULL) {
error = _do_lock_umtx(td, umtx, id, 0);
/* Mutex locking is restarted if it is interrupted. */
if (error == EINTR)
error = ERESTART;
} else {
getnanouptime(&ts);
timespecadd(&ts, timeout);
TIMESPEC_TO_TIMEVAL(&tv, timeout);
for (;;) {
error = _do_lock_umtx(td, umtx, id, tvtohz(&tv));
if (error != ETIMEDOUT)
break;
getnanouptime(&ts2);
if (timespeccmp(&ts2, &ts, >=)) {
error = ETIMEDOUT;
break;
}
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
}
/* Timed-locking is not restarted. */
if (error == ERESTART)
error = EINTR;
}
return (error);
}
/*
* Unlock a umtx object.
*/
static int
do_unlock_umtx(struct thread *td, struct umtx *umtx, uintptr_t id)
{
struct umtx_key key;
intptr_t owner;
intptr_t old;
int error;
int count;
/*
* Make sure we own this mtx.
*
* XXX Need a {fu,su}ptr this is not correct on arch where
* sizeof(intptr_t) != sizeof(long).
*/
owner = fuword(&umtx->u_owner);
if (owner == -1)
return (EFAULT);
if ((owner & ~UMTX_CONTESTED) != id)
return (EPERM);
/* This should be done in userland */
if ((owner & UMTX_CONTESTED) == 0) {
old = casuptr((intptr_t *)&umtx->u_owner, owner,
UMTX_UNOWNED);
if (old == -1)
return (EFAULT);
if (old == owner)
return (0);
owner = old;
}
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(umtx, TYPE_SIMPLE_LOCK, AUTO_SHARE,
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count(&key);
umtxq_unlock(&key);
/*
* When unlocking the umtx, it must be marked as unowned if
* there is zero or one thread only waiting for it.
* Otherwise, it must be marked as contested.
*/
old = casuptr((intptr_t *)&umtx->u_owner, owner,
count <= 1 ? UMTX_UNOWNED : UMTX_CONTESTED);
umtxq_lock(&key);
umtxq_signal(&key,1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
if (old == -1)
return (EFAULT);
if (old != owner)
return (EINVAL);
return (0);
}
#ifdef COMPAT_IA32
/*
* Lock a umtx object.
*/
static int
_do_lock_umtx32(struct thread *td, uint32_t *m, uint32_t id, int timo)
{
struct umtx_q *uq;
uint32_t owner;
uint32_t old;
int error = 0;
uq = td->td_umtxq;
/*
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
for (;;) {
/*
* Try the uncontested case. This should be done in userland.
*/
owner = casuword32(m, UMUTEX_UNOWNED, id);
/* The acquire succeeded. */
if (owner == UMUTEX_UNOWNED)
return (0);
/* The address was invalid. */
if (owner == -1)
return (EFAULT);
/* If no one owns it but it is contested try to acquire it. */
if (owner == UMUTEX_CONTESTED) {
owner = casuword32(m,
UMUTEX_CONTESTED, id | UMUTEX_CONTESTED);
if (owner == UMUTEX_CONTESTED)
return (0);
/* The address was invalid. */
if (owner == -1)
return (EFAULT);
/* If this failed the lock has changed, restart. */
continue;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
return (error);
if ((error = umtx_key_get(m, TYPE_SIMPLE_LOCK,
AUTO_SHARE, &uq->uq_key)) != 0)
return (error);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
* either some one else has acquired the lock or it has been
* released.
*/
old = casuword32(m, owner, owner | UMUTEX_CONTESTED);
/* The address was invalid. */
if (old == -1) {
umtxq_lock(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(&uq->uq_key);
if (old == owner)
error = umtxq_sleep(uq, "umtx", timo);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
}
return (0);
}
/*
* Lock a umtx object.
*/
static int
do_lock_umtx32(struct thread *td, void *m, uint32_t id,
struct timespec *timeout)
{
struct timespec ts, ts2, ts3;
struct timeval tv;
int error;
if (timeout == NULL) {
error = _do_lock_umtx32(td, m, id, 0);
/* Mutex locking is restarted if it is interrupted. */
if (error == EINTR)
error = ERESTART;
} else {
getnanouptime(&ts);
timespecadd(&ts, timeout);
TIMESPEC_TO_TIMEVAL(&tv, timeout);
for (;;) {
error = _do_lock_umtx32(td, m, id, tvtohz(&tv));
if (error != ETIMEDOUT)
break;
getnanouptime(&ts2);
if (timespeccmp(&ts2, &ts, >=)) {
error = ETIMEDOUT;
break;
}
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
}
/* Timed-locking is not restarted. */
if (error == ERESTART)
error = EINTR;
}
return (error);
}
/*
* Unlock a umtx object.
*/
static int
do_unlock_umtx32(struct thread *td, uint32_t *m, uint32_t id)
{
struct umtx_key key;
uint32_t owner;
uint32_t old;
int error;
int count;
/*
* Make sure we own this mtx.
*
* XXX Need a {fu,su}ptr this is not correct on arch where
* sizeof(intptr_t) != sizeof(long).
*/
owner = fuword32(m);
if (owner == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
/* This should be done in userland */
if ((owner & UMUTEX_CONTESTED) == 0) {
old = casuword32(m, owner, UMUTEX_UNOWNED);
if (old == -1)
return (EFAULT);
if (old == owner)
return (0);
owner = old;
}
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(m, TYPE_SIMPLE_LOCK, AUTO_SHARE,
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count(&key);
umtxq_unlock(&key);
/*
* When unlocking the umtx, it must be marked as unowned if
* there is zero or one thread only waiting for it.
* Otherwise, it must be marked as contested.
*/
old = casuword32(m, owner,
count <= 1 ? UMUTEX_UNOWNED : UMUTEX_CONTESTED);
umtxq_lock(&key);
umtxq_signal(&key,1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
if (old == -1)
return (EFAULT);
if (old != owner)
return (EINVAL);
return (0);
}
#endif
/*
* Fetch and compare value, sleep on the address if value is not changed.
*/
static int
do_wait(struct thread *td, void *addr, uintptr_t id,
struct timespec *timeout, int compat32)
{
struct umtx_q *uq;
struct timespec ts, ts2, ts3;
struct timeval tv;
uintptr_t tmp;
int error = 0;
uq = td->td_umtxq;
if ((error = umtx_key_get(addr, TYPE_SIMPLE_WAIT, AUTO_SHARE,
&uq->uq_key)) != 0)
return (error);
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
if (compat32 == 0)
tmp = fuword(addr);
else
tmp = fuword32(addr);
if (tmp != id) {
umtxq_lock(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
} else if (timeout == NULL) {
umtxq_lock(&uq->uq_key);
error = umtxq_sleep(uq, "ucond", 0);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
} else {
getnanouptime(&ts);
timespecadd(&ts, timeout);
TIMESPEC_TO_TIMEVAL(&tv, timeout);
umtxq_lock(&uq->uq_key);
for (;;) {
error = umtxq_sleep(uq, "ucond", tvtohz(&tv));
if (!(uq->uq_flags & UQF_UMTXQ))
break;
if (error != ETIMEDOUT)
break;
umtxq_unlock(&uq->uq_key);
getnanouptime(&ts2);
if (timespeccmp(&ts2, &ts, >=)) {
error = ETIMEDOUT;
umtxq_lock(&uq->uq_key);
break;
}
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
umtxq_lock(&uq->uq_key);
}
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
}
umtx_key_release(&uq->uq_key);
if (error == ERESTART)
error = EINTR;
return (error);
}
/*
* Wake up threads sleeping on the specified address.
*/
int
kern_umtx_wake(struct thread *td, void *uaddr, int n_wake)
{
struct umtx_key key;
int ret;
if ((ret = umtx_key_get(uaddr, TYPE_SIMPLE_WAIT, AUTO_SHARE,
&key)) != 0)
return (ret);
umtxq_lock(&key);
ret = umtxq_signal(&key, n_wake);
umtxq_unlock(&key);
umtx_key_release(&key);
return (0);
}
/*
* Lock PTHREAD_PRIO_NONE protocol POSIX mutex.
*/
static int
_do_lock_normal(struct thread *td, struct umutex *m, uint32_t flags, int timo,
int try)
{
struct umtx_q *uq;
uint32_t owner, old, id;
int error = 0;
id = td->td_tid;
uq = td->td_umtxq;
/*
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
for (;;) {
/*
* Try the uncontested case. This should be done in userland.
*/
owner = casuword32(&m->m_owner, UMUTEX_UNOWNED, id);
/* The acquire succeeded. */
if (owner == UMUTEX_UNOWNED)
return (0);
/* The address was invalid. */
if (owner == -1)
return (EFAULT);
/* If no one owns it but it is contested try to acquire it. */
if (owner == UMUTEX_CONTESTED) {
owner = casuword32(&m->m_owner,
UMUTEX_CONTESTED, id | UMUTEX_CONTESTED);
if (owner == UMUTEX_CONTESTED)
return (0);
/* The address was invalid. */
if (owner == -1)
return (EFAULT);
/* If this failed the lock has changed, restart. */
continue;
}
if ((flags & UMUTEX_ERROR_CHECK) != 0 &&
(owner & ~UMUTEX_CONTESTED) == id)
return (EDEADLK);
if (try != 0)
return (EBUSY);
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
return (error);
if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX,
GET_SHARE(flags), &uq->uq_key)) != 0)
return (error);
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
* either some one else has acquired the lock or it has been
* released.
*/
old = casuword32(&m->m_owner, owner, owner | UMUTEX_CONTESTED);
/* The address was invalid. */
if (old == -1) {
umtxq_lock(&uq->uq_key);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (EFAULT);
}
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(&uq->uq_key);
if (old == owner)
error = umtxq_sleep(uq, "umtxn", timo);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
}
return (0);
}
/*
* Lock PTHREAD_PRIO_NONE protocol POSIX mutex.
*/
/*
* Unlock PTHREAD_PRIO_NONE protocol POSIX mutex.
*/
static int
do_unlock_normal(struct thread *td, struct umutex *m, uint32_t flags)
{
struct umtx_key key;
uint32_t owner, old, id;
int error;
int count;
id = td->td_tid;
/*
* Make sure we own this mtx.
*/
owner = fuword32(&m->m_owner);
if (owner == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
/* This should be done in userland */
if ((owner & UMUTEX_CONTESTED) == 0) {
old = casuword32(&m->m_owner, owner, UMUTEX_UNOWNED);
if (old == -1)
return (EFAULT);
if (old == owner)
return (0);
owner = old;
}
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count(&key);
umtxq_unlock(&key);
/*
* When unlocking the umtx, it must be marked as unowned if
* there is zero or one thread only waiting for it.
* Otherwise, it must be marked as contested.
*/
old = casuword32(&m->m_owner, owner,
count <= 1 ? UMUTEX_UNOWNED : UMUTEX_CONTESTED);
umtxq_lock(&key);
umtxq_signal(&key,1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
if (old == -1)
return (EFAULT);
if (old != owner)
return (EINVAL);
return (0);
}
static inline struct umtx_pi *
umtx_pi_alloc(void)
{
struct umtx_pi *pi;
pi = uma_zalloc(umtx_pi_zone, M_ZERO | M_WAITOK);
TAILQ_INIT(&pi->pi_blocked);
atomic_add_int(&umtx_pi_allocated, 1);
return (pi);
}
static inline void
umtx_pi_free(struct umtx_pi *pi)
{
uma_zfree(umtx_pi_zone, pi);
atomic_add_int(&umtx_pi_allocated, -1);
}
/*
* Adjust the thread's position on a pi_state after its priority has been
* changed.
*/
static int
umtx_pi_adjust_thread(struct umtx_pi *pi, struct thread *td)
{
struct umtx_q *uq, *uq1, *uq2;
struct thread *td1;
mtx_assert(&sched_lock, MA_OWNED);
if (pi == NULL)
return (0);
uq = td->td_umtxq;
/*
* Check if the thread needs to be moved on the blocked chain.
* It needs to be moved if either its priority is lower than
* the previous thread or higher than the next thread.
*/
uq1 = TAILQ_PREV(uq, umtxq_head, uq_lockq);
uq2 = TAILQ_NEXT(uq, uq_lockq);
if ((uq1 != NULL && UPRI(td) < UPRI(uq1->uq_thread)) ||
(uq2 != NULL && UPRI(td) > UPRI(uq2->uq_thread))) {
/*
* Remove thread from blocked chain and determine where
* it should be moved to.
*/
TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
td1 = uq1->uq_thread;
MPASS(td1->td_proc->p_magic == P_MAGIC);
if (UPRI(td1) > UPRI(td))
break;
}
if (uq1 == NULL)
TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
else
TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
}
return (1);
}
/*
* Propagate priority when a thread is blocked on POSIX
* PI mutex.
*/
static void
umtx_propagate_priority(struct thread *td)
{
struct umtx_q *uq;
struct umtx_pi *pi;
int pri;
mtx_assert(&sched_lock, MA_OWNED);
pri = UPRI(td);
uq = td->td_umtxq;
pi = uq->uq_pi_blocked;
if (pi == NULL)
return;
for (;;) {
td = pi->pi_owner;
if (td == NULL)
return;
MPASS(td->td_proc != NULL);
MPASS(td->td_proc->p_magic == P_MAGIC);
if (UPRI(td) <= pri)
return;
sched_lend_user_prio(td, pri);
/*
* Pick up the lock that td is blocked on.
*/
uq = td->td_umtxq;
pi = uq->uq_pi_blocked;
/* Resort td on the list if needed. */
if (!umtx_pi_adjust_thread(pi, td))
break;
}
}
/*
* Unpropagate priority for a PI mutex when a thread blocked on
* it is interrupted by signal or resumed by others.
*/
static void
umtx_unpropagate_priority(struct umtx_pi *pi)
{
struct umtx_q *uq, *uq_owner;
struct umtx_pi *pi2;
int pri;
mtx_assert(&sched_lock, MA_OWNED);
while (pi != NULL && pi->pi_owner != NULL) {
pri = PRI_MAX;
uq_owner = pi->pi_owner->td_umtxq;
TAILQ_FOREACH(pi2, &uq_owner->uq_pi_contested, pi_link) {
uq = TAILQ_FIRST(&pi2->pi_blocked);
if (uq != NULL) {
if (pri > UPRI(uq->uq_thread))
pri = UPRI(uq->uq_thread);
}
}
if (pri > uq_owner->uq_inherited_pri)
pri = uq_owner->uq_inherited_pri;
sched_unlend_user_prio(pi->pi_owner, pri);
pi = uq_owner->uq_pi_blocked;
}
}
/*
* Insert a PI mutex into owned list.
*/
static void
umtx_pi_setowner(struct umtx_pi *pi, struct thread *owner)
{
struct umtx_q *uq_owner;
uq_owner = owner->td_umtxq;
mtx_assert(&sched_lock, MA_OWNED);
if (pi->pi_owner != NULL)
panic("pi_ower != NULL");
pi->pi_owner = owner;
TAILQ_INSERT_TAIL(&uq_owner->uq_pi_contested, pi, pi_link);
}
/*
* Claim ownership of a PI mutex.
*/
static int
umtx_pi_claim(struct umtx_pi *pi, struct thread *owner)
{
struct umtx_q *uq, *uq_owner;
uq_owner = owner->td_umtxq;
mtx_lock_spin(&sched_lock);
if (pi->pi_owner == owner) {
mtx_unlock_spin(&sched_lock);
return (0);
}
if (pi->pi_owner != NULL) {
/*
* userland may have already messed the mutex, sigh.
*/
mtx_unlock_spin(&sched_lock);
return (EPERM);
}
umtx_pi_setowner(pi, owner);
uq = TAILQ_FIRST(&pi->pi_blocked);
if (uq != NULL) {
int pri;
pri = UPRI(uq->uq_thread);
if (pri < UPRI(owner))
sched_lend_user_prio(owner, pri);
}
mtx_unlock_spin(&sched_lock);
return (0);
}
/*
* Adjust a thread's order position in its blocked PI mutex,
* this may result new priority propagating process.
*/
void
umtx_pi_adjust(struct thread *td, u_char oldpri)
{
struct umtx_q *uq;
struct umtx_pi *pi;
uq = td->td_umtxq;
mtx_assert(&sched_lock, MA_OWNED);
MPASS(TD_ON_UPILOCK(td));
/*
* Pick up the lock that td is blocked on.
*/
pi = uq->uq_pi_blocked;
MPASS(pi != NULL);
/* Resort the turnstile on the list. */
if (!umtx_pi_adjust_thread(pi, td))
return;
/*
* If our priority was lowered and we are at the head of the
* turnstile, then propagate our new priority up the chain.
*/
if (uq == TAILQ_FIRST(&pi->pi_blocked) && UPRI(td) < oldpri)
umtx_propagate_priority(td);
}
/*
* Sleep on a PI mutex.
*/
static int
umtxq_sleep_pi(struct umtx_q *uq, struct umtx_pi *pi,
uint32_t owner, const char *wmesg, int timo)
{
struct umtxq_chain *uc;
struct thread *td, *td1;
struct umtx_q *uq1;
int pri;
int error = 0;
td = uq->uq_thread;
KASSERT(td == curthread, ("inconsistent uq_thread"));
uc = umtxq_getchain(&uq->uq_key);
UMTXQ_LOCKED_ASSERT(uc);
umtxq_insert(uq);
if (pi->pi_owner == NULL) {
/* XXX
* Current, We only support process private PI-mutex,
* non-contended PI-mutexes are locked in userland.
* Process shared PI-mutex should always be initialized
* by kernel and be registered in kernel, locking should
* always be done by kernel to avoid security problems.
* For process private PI-mutex, we can find owner
* thread and boost its priority safely.
*/
PROC_LOCK(curproc);
td1 = thread_find(curproc, owner);
mtx_lock_spin(&sched_lock);
if (td1 != NULL && pi->pi_owner == NULL) {
uq1 = td1->td_umtxq;
umtx_pi_setowner(pi, td1);
}
PROC_UNLOCK(curproc);
} else {
mtx_lock_spin(&sched_lock);
}
TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
pri = UPRI(uq1->uq_thread);
if (pri > UPRI(td))
break;
}
if (uq1 != NULL)
TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
else
TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
uq->uq_pi_blocked = pi;
td->td_flags |= TDF_UPIBLOCKED;
mtx_unlock_spin(&sched_lock);
umtxq_unlock(&uq->uq_key);
mtx_lock_spin(&sched_lock);
umtx_propagate_priority(td);
mtx_unlock_spin(&sched_lock);
umtxq_lock(&uq->uq_key);
if (uq->uq_flags & UQF_UMTXQ) {
error = msleep(uq, &uc->uc_lock, PCATCH, wmesg, timo);
if (error == EWOULDBLOCK)
error = ETIMEDOUT;
if (uq->uq_flags & UQF_UMTXQ) {
umtxq_busy(&uq->uq_key);
umtxq_remove(uq);
umtxq_unbusy(&uq->uq_key);
}
}
umtxq_unlock(&uq->uq_key);
mtx_lock_spin(&sched_lock);
uq->uq_pi_blocked = NULL;
td->td_flags &= ~TDF_UPIBLOCKED;
TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
umtx_unpropagate_priority(pi);
mtx_unlock_spin(&sched_lock);
umtxq_lock(&uq->uq_key);
return (error);
}
/*
* Add reference count for a PI mutex.
*/
static void
umtx_pi_ref(struct umtx_pi *pi)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&pi->pi_key);
UMTXQ_LOCKED_ASSERT(uc);
pi->pi_refcount++;
}
/*
* Decrease reference count for a PI mutex, if the counter
* is decreased to zero, its memory space is freed.
*/
static void
umtx_pi_unref(struct umtx_pi *pi)
{
struct umtxq_chain *uc;
int free = 0;
uc = umtxq_getchain(&pi->pi_key);
UMTXQ_LOCKED_ASSERT(uc);
KASSERT(pi->pi_refcount > 0, ("invalid reference count"));
if (--pi->pi_refcount == 0) {
mtx_lock_spin(&sched_lock);
if (pi->pi_owner != NULL) {
TAILQ_REMOVE(&pi->pi_owner->td_umtxq->uq_pi_contested,
pi, pi_link);
pi->pi_owner = NULL;
}
KASSERT(TAILQ_EMPTY(&pi->pi_blocked),
("blocked queue not empty"));
mtx_unlock_spin(&sched_lock);
TAILQ_REMOVE(&uc->uc_pi_list, pi, pi_hashlink);
free = 1;
}
if (free)
umtx_pi_free(pi);
}
/*
* Find a PI mutex in hash table.
*/
static struct umtx_pi *
umtx_pi_lookup(struct umtx_key *key)
{
struct umtxq_chain *uc;
struct umtx_pi *pi;
uc = umtxq_getchain(key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_FOREACH(pi, &uc->uc_pi_list, pi_hashlink) {
if (umtx_key_match(&pi->pi_key, key)) {
return (pi);
}
}
return (NULL);
}
/*
* Insert a PI mutex into hash table.
*/
static inline void
umtx_pi_insert(struct umtx_pi *pi)
{
struct umtxq_chain *uc;
uc = umtxq_getchain(&pi->pi_key);
UMTXQ_LOCKED_ASSERT(uc);
TAILQ_INSERT_TAIL(&uc->uc_pi_list, pi, pi_hashlink);
}
/*
* Lock a PI mutex.
*/
static int
_do_lock_pi(struct thread *td, struct umutex *m, uint32_t flags, int timo,
int try)
{
struct umtx_q *uq;
struct umtx_pi *pi, *new_pi;
uint32_t id, owner, old;
int error;
id = td->td_tid;
uq = td->td_umtxq;
if ((error = umtx_key_get(m, TYPE_PI_UMUTEX, GET_SHARE(flags),
&uq->uq_key)) != 0)
return (error);
for (;;) {
pi = NULL;
umtxq_lock(&uq->uq_key);
pi = umtx_pi_lookup(&uq->uq_key);
if (pi == NULL) {
umtxq_unlock(&uq->uq_key);
new_pi = umtx_pi_alloc();
new_pi->pi_key = uq->uq_key;
umtxq_lock(&uq->uq_key);
pi = umtx_pi_lookup(&uq->uq_key);
if (pi != NULL)
umtx_pi_free(new_pi);
else {
umtx_pi_insert(new_pi);
pi = new_pi;
}
}
umtx_pi_ref(pi);
umtxq_unlock(&uq->uq_key);
/*
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
/*
* Try the uncontested case. This should be done in userland.
*/
owner = casuword32(&m->m_owner, UMUTEX_UNOWNED, id);
/* The acquire succeeded. */
if (owner == UMUTEX_UNOWNED) {
error = 0;
break;
}
/* The address was invalid. */
if (owner == -1) {
error = EFAULT;
break;
}
/* If no one owns it but it is contested try to acquire it. */
if (owner == UMUTEX_CONTESTED) {
owner = casuword32(&m->m_owner,
UMUTEX_CONTESTED, id | UMUTEX_CONTESTED);
if (owner == UMUTEX_CONTESTED) {
umtxq_lock(&uq->uq_key);
error = umtx_pi_claim(pi, td);
umtxq_unlock(&uq->uq_key);
break;
}
/* The address was invalid. */
if (owner == -1) {
error = EFAULT;
break;
}
/* If this failed the lock has changed, restart. */
umtxq_lock(&uq->uq_key);
umtx_pi_unref(pi);
umtxq_unlock(&uq->uq_key);
pi = NULL;
continue;
}
if ((flags & UMUTEX_ERROR_CHECK) != 0 &&
(owner & ~UMUTEX_CONTESTED) == id) {
error = EDEADLK;
break;
}
if (try != 0) {
error = EBUSY;
break;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
break;
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
* either some one else has acquired the lock or it has been
* released.
*/
old = casuword32(&m->m_owner, owner, owner | UMUTEX_CONTESTED);
/* The address was invalid. */
if (old == -1) {
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
error = EFAULT;
break;
}
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
if (old == owner)
error = umtxq_sleep_pi(uq, pi, owner & ~UMUTEX_CONTESTED,
"umtxpi", timo);
umtx_pi_unref(pi);
umtxq_unlock(&uq->uq_key);
pi = NULL;
}
if (pi != NULL) {
umtxq_lock(&uq->uq_key);
umtx_pi_unref(pi);
umtxq_unlock(&uq->uq_key);
}
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Unlock a PI mutex.
*/
static int
do_unlock_pi(struct thread *td, struct umutex *m, uint32_t flags)
{
struct umtx_key key;
struct umtx_q *uq_first, *uq_first2, *uq_me;
struct umtx_pi *pi, *pi2;
uint32_t owner, old, id;
int error;
int count;
int pri;
id = td->td_tid;
/*
* Make sure we own this mtx.
*/
owner = fuword32(&m->m_owner);
if (owner == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
/* This should be done in userland */
if ((owner & UMUTEX_CONTESTED) == 0) {
old = casuword32(&m->m_owner, owner, UMUTEX_UNOWNED);
if (old == -1)
return (EFAULT);
if (old == owner)
return (0);
owner = old;
}
/* We should only ever be in here for contested locks */
if ((error = umtx_key_get(m, TYPE_PI_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
count = umtxq_count_pi(&key, &uq_first);
if (uq_first != NULL) {
pi = uq_first->uq_pi_blocked;
if (pi->pi_owner != curthread) {
umtxq_unbusy(&key);
umtxq_unlock(&key);
/* userland messed the mutex */
return (EPERM);
}
uq_me = curthread->td_umtxq;
mtx_lock_spin(&sched_lock);
pi->pi_owner = NULL;
TAILQ_REMOVE(&uq_me->uq_pi_contested, pi, pi_link);
uq_first = TAILQ_FIRST(&pi->pi_blocked);
pri = PRI_MAX;
TAILQ_FOREACH(pi2, &uq_me->uq_pi_contested, pi_link) {
uq_first2 = TAILQ_FIRST(&pi2->pi_blocked);
if (uq_first2 != NULL) {
if (pri > UPRI(uq_first2->uq_thread))
pri = UPRI(uq_first2->uq_thread);
}
}
sched_unlend_user_prio(curthread, pri);
mtx_unlock_spin(&sched_lock);
}
umtxq_unlock(&key);
/*
* When unlocking the umtx, it must be marked as unowned if
* there is zero or one thread only waiting for it.
* Otherwise, it must be marked as contested.
*/
old = casuword32(&m->m_owner, owner,
count <= 1 ? UMUTEX_UNOWNED : UMUTEX_CONTESTED);
umtxq_lock(&key);
if (uq_first != NULL)
umtxq_signal_thread(uq_first);
umtxq_unbusy(&key);
umtxq_unlock(&key);
umtx_key_release(&key);
if (old == -1)
return (EFAULT);
if (old != owner)
return (EINVAL);
return (0);
}
/*
* Lock a PP mutex.
*/
static int
_do_lock_pp(struct thread *td, struct umutex *m, uint32_t flags, int timo,
int try)
{
struct umtx_q *uq, *uq2;
struct umtx_pi *pi;
uint32_t ceiling;
uint32_t owner, id;
int error, pri, old_inherited_pri, su;
id = td->td_tid;
uq = td->td_umtxq;
if ((error = umtx_key_get(m, TYPE_PP_UMUTEX, GET_SHARE(flags),
&uq->uq_key)) != 0)
return (error);
su = (suser(td) == 0);
for (;;) {
old_inherited_pri = uq->uq_inherited_pri;
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
ceiling = RTP_PRIO_MAX - fuword32(&m->m_ceilings[0]);
if (ceiling > RTP_PRIO_MAX) {
error = EINVAL;
goto out;
}
mtx_lock_spin(&sched_lock);
if (UPRI(td) < PRI_MIN_REALTIME + ceiling) {
mtx_unlock_spin(&sched_lock);
error = EINVAL;
goto out;
}
if (su && PRI_MIN_REALTIME + ceiling < uq->uq_inherited_pri) {
uq->uq_inherited_pri = PRI_MIN_REALTIME + ceiling;
if (uq->uq_inherited_pri < UPRI(td))
sched_lend_user_prio(td, uq->uq_inherited_pri);
}
mtx_unlock_spin(&sched_lock);
owner = casuword32(&m->m_owner,
UMUTEX_CONTESTED, id | UMUTEX_CONTESTED);
if (owner == UMUTEX_CONTESTED) {
error = 0;
break;
}
/* The address was invalid. */
if (owner == -1) {
error = EFAULT;
break;
}
if ((flags & UMUTEX_ERROR_CHECK) != 0 &&
(owner & ~UMUTEX_CONTESTED) == id) {
error = EDEADLK;
break;
}
if (try != 0) {
error = EBUSY;
break;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
break;
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "umtxpp", timo);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
mtx_lock_spin(&sched_lock);
uq->uq_inherited_pri = old_inherited_pri;
pri = PRI_MAX;
TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
uq2 = TAILQ_FIRST(&pi->pi_blocked);
if (uq2 != NULL) {
if (pri > UPRI(uq2->uq_thread))
pri = UPRI(uq2->uq_thread);
}
}
if (pri > uq->uq_inherited_pri)
pri = uq->uq_inherited_pri;
sched_unlend_user_prio(td, pri);
mtx_unlock_spin(&sched_lock);
}
if (error != 0) {
mtx_lock_spin(&sched_lock);
uq->uq_inherited_pri = old_inherited_pri;
pri = PRI_MAX;
TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
uq2 = TAILQ_FIRST(&pi->pi_blocked);
if (uq2 != NULL) {
if (pri > UPRI(uq2->uq_thread))
pri = UPRI(uq2->uq_thread);
}
}
if (pri > uq->uq_inherited_pri)
pri = uq->uq_inherited_pri;
sched_unlend_user_prio(td, pri);
mtx_unlock_spin(&sched_lock);
}
out:
umtxq_lock(&uq->uq_key);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
return (error);
}
/*
* Unlock a PP mutex.
*/
static int
do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags)
{
struct umtx_key key;
struct umtx_q *uq, *uq2;
struct umtx_pi *pi;
uint32_t owner, id;
uint32_t rceiling;
int error, pri, new_inherited_pri, su;
id = td->td_tid;
uq = td->td_umtxq;
su = (suser(td) == 0);
/*
* Make sure we own this mtx.
*/
owner = fuword32(&m->m_owner);
if (owner == -1)
return (EFAULT);
if ((owner & ~UMUTEX_CONTESTED) != id)
return (EPERM);
error = copyin(&m->m_ceilings[1], &rceiling, sizeof(uint32_t));
if (error != 0)
return (error);
if (rceiling == -1)
new_inherited_pri = PRI_MAX;
else {
rceiling = RTP_PRIO_MAX - rceiling;
if (rceiling > RTP_PRIO_MAX)
return (EINVAL);
new_inherited_pri = PRI_MIN_REALTIME + rceiling;
}
if ((error = umtx_key_get(m, TYPE_PP_UMUTEX, GET_SHARE(flags),
&key)) != 0)
return (error);
umtxq_lock(&key);
umtxq_busy(&key);
umtxq_unlock(&key);
/*
* For priority protected mutex, always set unlocked state
* to UMUTEX_CONTESTED, so that userland always enters kernel
* to lock the mutex, it is necessary because thread priority
* has to be adjusted for such mutex.
*/
error = suword32(&m->m_owner, UMUTEX_CONTESTED);
umtxq_lock(&key);
if (error == 0)
umtxq_signal(&key, 1);
umtxq_unbusy(&key);
umtxq_unlock(&key);
if (error == -1)
error = EFAULT;
else {
mtx_lock_spin(&sched_lock);
if (su != 0)
uq->uq_inherited_pri = new_inherited_pri;
pri = PRI_MAX;
TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
uq2 = TAILQ_FIRST(&pi->pi_blocked);
if (uq2 != NULL) {
if (pri > UPRI(uq2->uq_thread))
pri = UPRI(uq2->uq_thread);
}
}
if (pri > uq->uq_inherited_pri)
pri = uq->uq_inherited_pri;
sched_unlend_user_prio(td, pri);
mtx_unlock_spin(&sched_lock);
}
umtx_key_release(&key);
return (error);
}
static int
do_set_ceiling(struct thread *td, struct umutex *m, uint32_t ceiling,
uint32_t *old_ceiling)
{
struct umtx_q *uq;
uint32_t save_ceiling;
uint32_t owner, id;
uint32_t flags;
int error;
flags = fuword32(&m->m_flags);
if ((flags & UMUTEX_PRIO_PROTECT) == 0)
return (EINVAL);
if (ceiling > RTP_PRIO_MAX)
return (EINVAL);
id = td->td_tid;
uq = td->td_umtxq;
if ((error = umtx_key_get(m, TYPE_PP_UMUTEX, GET_SHARE(flags),
&uq->uq_key)) != 0)
return (error);
for (;;) {
umtxq_lock(&uq->uq_key);
umtxq_busy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
save_ceiling = fuword32(&m->m_ceilings[0]);
owner = casuword32(&m->m_owner,
UMUTEX_CONTESTED, id | UMUTEX_CONTESTED);
if (owner == UMUTEX_CONTESTED) {
suword32(&m->m_ceilings[0], ceiling);
suword32(&m->m_owner, UMUTEX_CONTESTED);
error = 0;
break;
}
/* The address was invalid. */
if (owner == -1) {
error = EFAULT;
break;
}
if ((owner & ~UMUTEX_CONTESTED) == id) {
suword32(&m->m_ceilings[0], ceiling);
error = 0;
break;
}
/*
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error != 0)
break;
/*
* We set the contested bit, sleep. Otherwise the lock changed
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unbusy(&uq->uq_key);
error = umtxq_sleep(uq, "umtxpp", 0);
umtxq_remove(uq);
umtxq_unlock(&uq->uq_key);
}
umtxq_lock(&uq->uq_key);
if (error == 0)
umtxq_signal(&uq->uq_key, INT_MAX);
umtxq_unbusy(&uq->uq_key);
umtxq_unlock(&uq->uq_key);
umtx_key_release(&uq->uq_key);
if (error == 0 && old_ceiling != NULL)
suword32(old_ceiling, save_ceiling);
return (error);
}
static int
_do_lock_umutex(struct thread *td, struct umutex *m, int flags, int timo,
int try)
{
switch(flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
case 0:
return (_do_lock_normal(td, m, flags, timo, try));
case UMUTEX_PRIO_INHERIT:
return (_do_lock_pi(td, m, flags, timo, try));
case UMUTEX_PRIO_PROTECT:
return (_do_lock_pp(td, m, flags, timo, try));
}
return (EINVAL);
}
/*
* Lock a userland POSIX mutex.
*/
static int
do_lock_umutex(struct thread *td, struct umutex *m,
struct timespec *timeout, int try)
{
struct timespec ts, ts2, ts3;
struct timeval tv;
uint32_t flags;
int error;
flags = fuword32(&m->m_flags);
if (flags == -1)
return (EFAULT);
if (timeout == NULL) {
error = _do_lock_umutex(td, m, flags, 0, try);
/* Mutex locking is restarted if it is interrupted. */
if (error == EINTR)
error = ERESTART;
} else {
getnanouptime(&ts);
timespecadd(&ts, timeout);
TIMESPEC_TO_TIMEVAL(&tv, timeout);
for (;;) {
error = _do_lock_umutex(td, m, flags, tvtohz(&tv), try);
if (error != ETIMEDOUT)
break;
getnanouptime(&ts2);
if (timespeccmp(&ts2, &ts, >=)) {
error = ETIMEDOUT;
break;
}
ts3 = ts;
timespecsub(&ts3, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts3);
}
/* Timed-locking is not restarted. */
if (error == ERESTART)
error = EINTR;
}
return (error);
}
/*
* Unlock a userland POSIX mutex.
*/
static int
do_unlock_umutex(struct thread *td, struct umutex *m)
{
uint32_t flags;
flags = fuword32(&m->m_flags);
if (flags == -1)
return (EFAULT);
switch(flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
case 0:
return (do_unlock_normal(td, m, flags));
case UMUTEX_PRIO_INHERIT:
return (do_unlock_pi(td, m, flags));
case UMUTEX_PRIO_PROTECT:
return (do_unlock_pp(td, m, flags));
}
return (EINVAL);
}
int
_umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
/* struct umtx *umtx */
{
return _do_lock_umtx(td, uap->umtx, td->td_tid, 0);
}
int
_umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
/* struct umtx *umtx */
{
return do_unlock_umtx(td, uap->umtx, td->td_tid);
}
static int
__umtx_op_lock_umtx(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = copyin(uap->uaddr2, &timeout, sizeof(timeout));
if (error != 0)
return (error);
if (timeout.tv_nsec >= 1000000000 ||
timeout.tv_nsec < 0) {
return (EINVAL);
}
ts = &timeout;
}
return (do_lock_umtx(td, uap->obj, uap->val, ts));
}
static int
__umtx_op_unlock_umtx(struct thread *td, struct _umtx_op_args *uap)
{
return (do_unlock_umtx(td, uap->obj, uap->val));
}
static int
__umtx_op_wait(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = copyin(uap->uaddr2, &timeout, sizeof(timeout));
if (error != 0)
return (error);
if (timeout.tv_nsec >= 1000000000 ||
timeout.tv_nsec < 0)
return (EINVAL);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 0);
}
static int
__umtx_op_wake(struct thread *td, struct _umtx_op_args *uap)
{
return (kern_umtx_wake(td, uap->obj, uap->val));
}
static int
__umtx_op_lock_umutex(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = copyin(uap->uaddr2, &timeout,
sizeof(timeout));
if (error != 0)
return (error);
if (timeout.tv_nsec >= 1000000000 ||
timeout.tv_nsec < 0) {
return (EINVAL);
}
ts = &timeout;
}
return do_lock_umutex(td, uap->obj, ts, 0);
}
static int
__umtx_op_trylock_umutex(struct thread *td, struct _umtx_op_args *uap)
{
return do_lock_umutex(td, uap->obj, NULL, 1);
}
static int
__umtx_op_unlock_umutex(struct thread *td, struct _umtx_op_args *uap)
{
return do_unlock_umutex(td, uap->obj);
}
static int
__umtx_op_set_ceiling(struct thread *td, struct _umtx_op_args *uap)
{
return do_set_ceiling(td, uap->obj, uap->val, uap->uaddr1);
}
typedef int (*_umtx_op_func)(struct thread *td, struct _umtx_op_args *uap);
static _umtx_op_func op_table[] = {
__umtx_op_lock_umtx, /* UMTX_OP_LOCK */
__umtx_op_unlock_umtx, /* UMTX_OP_UNLOCK */
__umtx_op_wait, /* UMTX_OP_WAIT */
__umtx_op_wake, /* UMTX_OP_WAKE */
__umtx_op_trylock_umutex, /* UMTX_OP_MUTEX_TRYLOCK */
__umtx_op_lock_umutex, /* UMTX_OP_MUTEX_LOCK */
__umtx_op_unlock_umutex, /* UMTX_OP_MUTEX_UNLOCK */
__umtx_op_set_ceiling /* UMTX_OP_SET_CEILING */
};
int
_umtx_op(struct thread *td, struct _umtx_op_args *uap)
{
if (uap->op >= 0 && uap->op < UMTX_OP_MAX)
return (*op_table[uap->op])(td, uap);
return (EINVAL);
}
#ifdef COMPAT_IA32
int
freebsd32_umtx_lock(struct thread *td, struct freebsd32_umtx_lock_args *uap)
/* struct umtx *umtx */
{
return (do_lock_umtx32(td, (uint32_t *)uap->umtx, td->td_tid, NULL));
}
int
freebsd32_umtx_unlock(struct thread *td, struct freebsd32_umtx_unlock_args *uap)
/* struct umtx *umtx */
{
return (do_unlock_umtx32(td, (uint32_t *)uap->umtx, td->td_tid));
}
struct timespec32 {
u_int32_t tv_sec;
u_int32_t tv_nsec;
};
static inline int
copyin_timeout32(void *addr, struct timespec *tsp)
{
struct timespec32 ts32;
int error;
error = copyin(addr, &ts32, sizeof(struct timespec32));
if (error == 0) {
tsp->tv_sec = ts32.tv_sec;
tsp->tv_nsec = ts32.tv_nsec;
}
return (error);
}
static int
__umtx_op_lock_umtx_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = copyin_timeout32(uap->uaddr2, &timeout);
if (error != 0)
return (error);
if (timeout.tv_nsec >= 1000000000 ||
timeout.tv_nsec < 0) {
return (EINVAL);
}
ts = &timeout;
}
return (do_lock_umtx32(td, uap->obj, uap->val, ts));
}
static int
__umtx_op_unlock_umtx_compat32(struct thread *td, struct _umtx_op_args *uap)
{
return (do_unlock_umtx32(td, uap->obj, (uint32_t)uap->val));
}
static int
__umtx_op_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = copyin_timeout32(uap->uaddr2, &timeout);
if (error != 0)
return (error);
if (timeout.tv_nsec >= 1000000000 ||
timeout.tv_nsec < 0)
return (EINVAL);
ts = &timeout;
}
return do_wait(td, uap->obj, uap->val, ts, 1);
}
static int
__umtx_op_lock_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec *ts, timeout;
int error;
/* Allow a null timespec (wait forever). */
if (uap->uaddr2 == NULL)
ts = NULL;
else {
error = copyin_timeout32(uap->uaddr2, &timeout);
if (error != 0)
return (error);
if (timeout.tv_nsec >= 1000000000 ||
timeout.tv_nsec < 0)
return (EINVAL);
ts = &timeout;
}
return do_lock_umutex(td, uap->obj, ts, 0);
}
static _umtx_op_func op_table_compat32[] = {
__umtx_op_lock_umtx_compat32, /* UMTX_OP_LOCK */
__umtx_op_unlock_umtx_compat32, /* UMTX_OP_UNLOCK */
__umtx_op_wait_compat32, /* UMTX_OP_WAIT */
__umtx_op_wake, /* UMTX_OP_WAKE */
__umtx_op_trylock_umutex, /* UMTX_OP_MUTEX_LOCK */
__umtx_op_lock_umutex_compat32, /* UMTX_OP_MUTEX_TRYLOCK */
__umtx_op_unlock_umutex, /* UMTX_OP_MUTEX_UNLOCK */
__umtx_op_set_ceiling /* UMTX_OP_SET_CEILING */
};
int
freebsd32_umtx_op(struct thread *td, struct freebsd32_umtx_op_args *uap)
{
if (uap->op >= 0 && uap->op < UMTX_OP_MAX)
return (*op_table_compat32[uap->op])(td,
(struct _umtx_op_args *)uap);
return (EINVAL);
}
#endif
void
umtx_thread_init(struct thread *td)
{
td->td_umtxq = umtxq_alloc();
td->td_umtxq->uq_thread = td;
}
void
umtx_thread_fini(struct thread *td)
{
umtxq_free(td->td_umtxq);
}
/*
* It will be called when new thread is created, e.g fork().
*/
void
umtx_thread_alloc(struct thread *td)
{
struct umtx_q *uq;
uq = td->td_umtxq;
uq->uq_inherited_pri = PRI_MAX;
KASSERT(uq->uq_flags == 0, ("uq_flags != 0"));
KASSERT(uq->uq_thread == td, ("uq_thread != td"));
KASSERT(uq->uq_pi_blocked == NULL, ("uq_pi_blocked != NULL"));
KASSERT(TAILQ_EMPTY(&uq->uq_pi_contested), ("uq_pi_contested is not empty"));
}
/*
* exec() hook.
*/
static void
umtx_exec_hook(void *arg __unused, struct proc *p __unused,
struct image_params *imgp __unused)
{
umtx_thread_cleanup(curthread);
}
/*
* thread_exit() hook.
*/
void
umtx_thread_exit(struct thread *td)
{
umtx_thread_cleanup(td);
}
/*
* clean up umtx data.
*/
static void
umtx_thread_cleanup(struct thread *td)
{
struct umtx_q *uq;
struct umtx_pi *pi;
if ((uq = td->td_umtxq) == NULL)
return;
mtx_lock_spin(&sched_lock);
uq->uq_inherited_pri = PRI_MAX;
while ((pi = TAILQ_FIRST(&uq->uq_pi_contested)) != NULL) {
pi->pi_owner = NULL;
TAILQ_REMOVE(&uq->uq_pi_contested, pi, pi_link);
}
td->td_flags &= ~TDF_UBORROWING;
mtx_unlock_spin(&sched_lock);
}
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