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1. make umtx sharable between processes, the way is two or more processes

Browse Source 
call mmap() to create a shared space, and then initialize umtx on it,
   after that, each thread in different processes can use the umtx same
   as threads in same process.
2. introduce a new syscall _umtx_op to support timed lock and condition
   variable semantics. also, orignal umtx_lock and umtx_unlock inline
   functions now are reimplemented by using _umtx_op, the _umtx_op can
   use arbitrary id not just a thread id.
This commit is contained in:
David Xu 2004-12-18 12:52:44 +00:00
parent 9a5393ac68
commit 50586e8b6b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=139013
9 changed files with 621 additions and 185 deletions
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1
sys/kern/init_sysent.c
View File

@ -482,4 +482,5 @@ struct sysent sysent[] = {
{ SYF_MPSAFE | AS(getaudit_addr_args), (sy_call_t *)lkmressys }, /* 451 = getaudit_addr */
{ SYF_MPSAFE | AS(setaudit_addr_args), (sy_call_t *)lkmressys }, /* 452 = setaudit_addr */
{ SYF_MPSAFE | AS(auditctl_args), (sy_call_t *)lkmressys }, /* 453 = auditctl */
{ SYF_MPSAFE | AS(_umtx_op_args), (sy_call_t *)_umtx_op }, /* 454 = _umtx_op */
};

724
sys/kern/kern_umtx.c
View File

@ -1,4 +1,5 @@
/*
* Copyright (c) 2004, David Xu <davidxu@freebsd.org>
* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
@ -37,21 +38,51 @@ __FBSDID("$FreeBSD$");
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/eventhandler.h>
#include <sys/thr.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>
#define UMTX_PRIVATE 0
#define UMTX_SHARED 1
#define UMTX_STATIC_SHARED
struct umtx_key {
int type;
union {
struct {
vm_object_t object;
long offset;
} shared;
struct {
struct umtx *umtx;
long pid;
} private;
struct {
void *ptr;
long word;
} both;
} info;
};
struct umtx_q {
LIST_ENTRY(umtx_q) uq_next; /* Linked list for the hash. */
TAILQ_HEAD(, thread) uq_tdq; /* List of threads blocked here. */
struct umtx *uq_umtx; /* Pointer key component. */
pid_t uq_pid; /* Pid key component. */
int uq_count; /* How many threads blocked. */
struct umtx_key uq_key; /* Umtx key. */
struct thread *uq_thread; /* The thread waits on */
LIST_ENTRY(umtx_q) uq_rqnext; /* Linked list for requeuing. */
vm_offset_t uq_addr; /* Umtx's virtual address. */
};
LIST_HEAD(umtx_head, umtx_q);
struct umtxq_chain {
struct mtx uc_lock; /* lock for this chain. */
struct umtx_head uc_queues; /* List of sleep queues. */
struct mtx uc_lock; /* Lock for this chain. */
struct umtx_head uc_queue; /* List of sleep queues. */
};
#define GOLDEN_RATIO_PRIME 2654404609U
@ -63,203 +94,344 @@ static MALLOC_DEFINE(M_UMTX, "umtx", "UMTX queue memory");
#define UMTX_CONTESTED LONG_MIN
static void umtx_init_chains(void *);
static int umtxq_hash(struct thread *, struct umtx *);
static void umtxq_lock(struct thread *td, struct umtx *key);
static void umtxq_unlock(struct thread *td, struct umtx *key);
static struct umtx_q *umtxq_lookup(struct thread *, struct umtx *);
static struct umtx_q *umtxq_insert(struct thread *, struct umtx *);
static int umtxq_count(struct thread *td, struct umtx *umtx);
static int umtx_sleep(struct thread *td, struct umtx *umtx, int priority,
const char *wmesg, int timo);
static void umtx_signal(struct thread *td, struct umtx *umtx);
static void umtxq_init_chains(void *);
static int umtxq_hash(struct umtx_key *key);
static struct mtx *umtxq_mtx(int chain);
static void umtxq_lock(struct umtx_key *key);
static void umtxq_unlock(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 thread *td, struct umtx_key *key,
int prio, const char *wmesg, int timo);
static int umtxq_count(struct umtx_key *key);
static void umtxq_signal(struct umtx_key *key);
static void umtxq_broadcast(struct umtx_key *key);
#ifdef UMTX_DYNAMIC_SHARED
static void fork_handler(void *arg, struct proc *p1, struct proc *p2,
int flags);
#endif
static int umtx_key_match(const struct umtx_key *k1, const struct umtx_key *k2);
static int umtx_key_get(struct thread *td, struct umtx *umtx,
struct umtx_key *key);
static void umtx_key_release(struct umtx_key *key);
SYSINIT(umtx, SI_SUB_LOCK, SI_ORDER_MIDDLE, umtx_init_chains, NULL);
SYSINIT(umtx, SI_SUB_EVENTHANDLER+1, SI_ORDER_MIDDLE, umtxq_init_chains, NULL);
static void
umtx_init_chains(void *arg __unused)
umtxq_init_chains(void *arg __unused)
{
int i;
for (i = 0; i < UMTX_CHAINS; ++i) {
mtx_init(&umtxq_chains[i].uc_lock, "umtxq_lock", NULL,
MTX_DEF | MTX_DUPOK);
LIST_INIT(&umtxq_chains[i].uc_queues);
LIST_INIT(&umtxq_chains[i].uc_queue);
}
#ifdef UMTX_DYNAMIC_SHARED
EVENTHANDLER_REGISTER(process_fork, fork_handler, 0, 10000);
#endif
}
static inline int
umtxq_hash(struct thread *td, struct umtx *umtx)
umtxq_hash(struct umtx_key *key)
{
unsigned n = (uintptr_t)umtx + td->td_proc->p_pid;
unsigned n = (uintptr_t)key->info.both.ptr + key->info.both.word;
return (((n * GOLDEN_RATIO_PRIME) >> UMTX_SHIFTS) % UMTX_CHAINS);
}
static inline void
umtxq_lock(struct thread *td, struct umtx *key)
static inline int
umtx_key_match(const struct umtx_key *k1, const struct umtx_key *k2)
{
int chain = umtxq_hash(td, key);
mtx_lock(&umtxq_chains[chain].uc_lock);
return (k1->type == k2->type &&
k1->info.both.ptr == k2->info.both.ptr &&
k1->info.both.word == k2->info.both.word);
}
static inline struct mtx *
umtxq_mtx(int chain)
{
return (&umtxq_chains[chain].uc_lock);
}
static inline void
umtxq_unlock(struct thread *td, struct umtx *key)
umtxq_lock(struct umtx_key *key)
{
int chain = umtxq_hash(td, key);
mtx_unlock(&umtxq_chains[chain].uc_lock);
int chain = umtxq_hash(key);
mtx_lock(umtxq_mtx(chain));
}
static struct umtx_q *
umtxq_lookup(struct thread *td, struct umtx *umtx)
static inline void
umtxq_unlock(struct umtx_key *key)
{
struct umtx_head *head;
struct umtx_q *uq;
pid_t pid;
int chain;
chain = umtxq_hash(td, umtx);
mtx_assert(&umtxq_chains[chain].uc_lock, MA_OWNED);
pid = td->td_proc->p_pid;
head = &umtxq_chains[chain].uc_queues;
LIST_FOREACH(uq, head, uq_next) {
if (uq->uq_pid == pid && uq->uq_umtx == umtx)
return (uq);
}
return (NULL);
int chain = umtxq_hash(key);
mtx_unlock(umtxq_mtx(chain));
}
/*
* Insert a thread onto the umtx queue.
*/
static struct umtx_q *
umtxq_insert(struct thread *td, struct umtx *umtx)
static inline void
umtxq_insert(struct umtx_q *uq)
{
struct umtx_head *head;
struct umtx_q *uq, *ins = NULL;
pid_t pid;
int chain;
int chain = umtxq_hash(&uq->uq_key);
chain = umtxq_hash(td, umtx);
pid = td->td_proc->p_pid;
if ((uq = umtxq_lookup(td, umtx)) == NULL) {
umtxq_unlock(td, umtx);
ins = malloc(sizeof(*uq), M_UMTX, M_ZERO | M_WAITOK);
umtxq_lock(td, umtx);
/*
* Some one else could have succeeded while we were blocked
* waiting on memory.
*/
if ((uq = umtxq_lookup(td, umtx)) == NULL) {
head = &umtxq_chains[chain].uc_queues;
uq = ins;
uq->uq_pid = pid;
uq->uq_umtx = umtx;
uq->uq_count = 0;
LIST_INSERT_HEAD(head, uq, uq_next);
TAILQ_INIT(&uq->uq_tdq);
ins = NULL;
}
}
TAILQ_INSERT_TAIL(&uq->uq_tdq, td, td_umtx);
uq->uq_count++;
if (ins) {
umtxq_unlock(td, umtx);
free(ins, M_UMTX);
umtxq_lock(td, umtx);
}
return (uq);
head = &umtxq_chains[chain].uc_queue;
LIST_INSERT_HEAD(head, uq, uq_next);
uq->uq_thread->td_umtxq = uq;
mtx_lock_spin(&sched_lock);
uq->uq_thread->td_flags |= TDF_UMTXQ;
mtx_unlock_spin(&sched_lock);
}
/*
* Remove thread from umtx queue, umtx chain lock is also
* released.
* Remove thread from the umtx queue.
*/
static void
umtx_remove(struct umtx_q *uq, struct thread *td, struct umtx *umtx)
static inline void
umtxq_remove(struct umtx_q *uq)
{
int chain;
chain = umtxq_hash(td, umtx);
mtx_assert(&umtxq_chains[chain].uc_lock, MA_OWNED);
TAILQ_REMOVE(&uq->uq_tdq, td, td_umtx);
uq->uq_count--;
if (TAILQ_EMPTY(&uq->uq_tdq)) {
if (uq->uq_thread->td_flags & TDF_UMTXQ) {
LIST_REMOVE(uq, uq_next);
umtxq_unlock(td, umtx);
free(uq, M_UMTX);
} else
umtxq_unlock(td, umtx);
uq->uq_thread->td_umtxq = NULL;
/* turning off TDF_UMTXQ should be the last thing. */
mtx_lock_spin(&sched_lock);
uq->uq_thread->td_flags &= ~TDF_UMTXQ;
mtx_unlock_spin(&sched_lock);
}
}
static inline int
umtxq_count(struct thread *td, struct umtx *umtx)
static int
umtxq_count(struct umtx_key *key)
{
struct umtx_q *uq;
int count = 0;
struct umtx_head *head;
int chain, count = 0;
umtxq_lock(td, umtx);
if ((uq = umtxq_lookup(td, umtx)) != NULL)
count = uq->uq_count;
umtxq_unlock(td, umtx);
chain = umtxq_hash(key);
umtxq_lock(key);
head = &umtxq_chains[chain].uc_queue;
LIST_FOREACH(uq, head, uq_next) {
if (umtx_key_match(&uq->uq_key, key)) {
if (++count > 1)
break;
}
}
umtxq_unlock(key);
return (count);
}
static inline int
umtx_sleep(struct thread *td, struct umtx *umtx, int priority,
const char *wmesg, int timo)
{
int chain;
chain = umtxq_hash(td, umtx);
mtx_assert(&umtxq_chains[chain].uc_lock, MA_OWNED);
return (msleep(td, &umtxq_chains[chain].uc_lock, priority,
wmesg, timo));
}
static void
umtx_signal(struct thread *td, struct umtx *umtx)
umtxq_signal(struct umtx_key *key)
{
struct umtx_q *uq;
struct umtx_head *head;
struct thread *blocked = NULL;
int chain;
umtxq_lock(td, umtx);
if ((uq = umtxq_lookup(td, umtx)) != NULL) {
if ((blocked = TAILQ_FIRST(&uq->uq_tdq)) != NULL) {
mtx_lock_spin(&sched_lock);
blocked->td_flags |= TDF_UMTXWAKEUP;
mtx_unlock_spin(&sched_lock);
chain = umtxq_hash(key);
umtxq_lock(key);
head = &umtxq_chains[chain].uc_queue;
LIST_FOREACH(uq, head, uq_next) {
if (umtx_key_match(&uq->uq_key, key)) {
blocked = uq->uq_thread;
umtxq_remove(uq);
break;
}
}
umtxq_unlock(td, umtx);
umtxq_unlock(key);
if (blocked != NULL)
wakeup(blocked);
}
int
_umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
/* struct umtx *umtx */
static void
umtxq_broadcast(struct umtx_key *key)
{
struct umtx_q *uq, *next;
struct umtx_head *head;
struct thread *blocked;
int chain;
chain = umtxq_hash(key);
umtxq_lock(key);
head = &umtxq_chains[chain].uc_queue;
for (uq = LIST_FIRST(head); uq != NULL; uq = next) {
next = LIST_NEXT(uq, uq_next);
if (umtx_key_match(&uq->uq_key, key)) {
blocked = uq->uq_thread;
umtxq_remove(uq);
wakeup(blocked);
}
uq = next;
}
umtxq_unlock(key);
}
static inline int
umtxq_sleep(struct thread *td, struct umtx_key *key, int priority,
const char *wmesg, int timo)
{
int error;
int chain = umtxq_hash(key);
error = msleep(td, umtxq_mtx(chain), priority, wmesg, timo);
return (error);
}
static int
umtx_key_get(struct thread *td, struct umtx *umtx, struct umtx_key *key)
{
#if defined(UMTX_DYNAMIC_SHARED) || defined(UMTX_STATIC_SHARED)
vm_map_t map;
vm_map_entry_t entry;
vm_pindex_t pindex;
vm_prot_t prot;
boolean_t wired;
map = &td->td_proc->p_vmspace->vm_map;
if (vm_map_lookup(&map, (vm_offset_t)umtx, VM_PROT_WRITE,
&entry, &key->info.shared.object, &pindex, &prot,
&wired) != KERN_SUCCESS) {
return EFAULT;
}
#endif
#if defined(UMTX_DYNAMIC_SHARED)
key->type = UMTX_SHARED;
key->info.shared.offset = entry->offset + entry->start -
(vm_offset_t)umtx;
/*
* Add object reference, if we don't do this, a buggy application
* deallocates the object, the object will be reused by other
* applications, then unlock will wake wrong thread.
*/
vm_object_reference(key->info.shared.object);
vm_map_lookup_done(map, entry);
#elif defined(UMTX_STATIC_SHARED)
if (VM_INHERIT_SHARE == entry->inheritance) {
key->type = UMTX_SHARED;
key->info.shared.offset = entry->offset + entry->start -
(vm_offset_t)umtx;
vm_object_reference(key->info.shared.object);
} else {
key->type = UMTX_PRIVATE;
key->info.private.umtx = umtx;
key->info.private.pid = td->td_proc->p_pid;
}
vm_map_lookup_done(map, entry);
#else
key->type = UMTX_PRIVATE;
key->info.private.umtx = umtx;
key->info.private.pid = td->td_proc->p_pid;
#endif
return (0);
}
static inline void
umtx_key_release(struct umtx_key *key)
{
if (key->type == UMTX_SHARED)
vm_object_deallocate(key->info.shared.object);
}
static inline int
umtxq_queue_me(struct thread *td, struct umtx *umtx, struct umtx_q *uq)
{
int error;
if ((error = umtx_key_get(td, umtx, &uq->uq_key)) != 0)
return (error);
uq->uq_addr = (vm_offset_t)umtx;
uq->uq_thread = td;
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
return (0);
}
#if defined(UMTX_DYNAMIC_SHARED)
static void
fork_handler(void *arg, struct proc *p1, struct proc *p2, int flags)
{
vm_map_t map;
vm_map_entry_t entry;
vm_object_t object;
vm_pindex_t pindex;
vm_prot_t prot;
boolean_t wired;
struct umtx_key key;
LIST_HEAD(, umtx_q) workq;
struct umtx_q *uq;
struct umtx *umtx;
struct thread *td;
int onq;
LIST_INIT(&workq);
/* Collect threads waiting on umtxq */
PROC_LOCK(p1);
FOREACH_THREAD_IN_PROC(p1, td) {
if (td->td_flags & TDF_UMTXQ) {
uq = td->td_umtxq;
if (uq)
LIST_INSERT_HEAD(&workq, uq, uq_rqnext);
}
}
PROC_UNLOCK(p1);
LIST_FOREACH(uq, &workq, uq_rqnext) {
map = &p1->p_vmspace->vm_map;
if (vm_map_lookup(&map, uq->uq_addr, VM_PROT_WRITE,
&entry, &object, &pindex, &prot, &wired) != KERN_SUCCESS) {
continue;
}
key.type = UMTX_SHARED;
key.info.shared.object = object;
key.info.shared.offset = entry->offset + entry->start -
uq->uq_addr;
if (umtx_key_match(&key, &uq->uq_key)) {
vm_map_lookup_done(map, entry);
continue;
}
umtxq_lock(&uq->uq_key);
if (uq->uq_thread->td_flags & TDF_UMTXQ) {
umtxq_remove(uq);
onq = 1;
} else
onq = 0;
umtxq_unlock(&uq->uq_key);
if (onq) {
vm_object_deallocate(uq->uq_key.info.shared.object);
uq->uq_key = key;
umtxq_lock(&uq->uq_key);
umtxq_insert(uq);
umtxq_unlock(&uq->uq_key);
vm_object_reference(uq->uq_key.info.shared.object);
}
vm_map_lookup_done(map, entry);
}
}
#endif
static int
_do_lock(struct thread *td, struct umtx *umtx, long id, int timo)
{
struct umtx_q uq;
intptr_t owner;
intptr_t old;
int error = 0;
uq = NULL;
/*
* Care must be exercised when dealing with this structure. It
* Care must be exercised when dealing with umtx structure. It
* can fault on any access.
*/
umtx = uap->umtx;
for (;;) {
/*
* Try the uncontested case. This should be done in userland.
*/
owner = casuptr((intptr_t *)&umtx->u_owner,
UMTX_UNOWNED, td->td_tid);
UMTX_UNOWNED, id);
/* The acquire succeeded. */
if (owner == UMTX_UNOWNED)
@ -272,7 +444,7 @@ _umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
/* 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, td->td_tid | UMTX_CONTESTED);
UMTX_CONTESTED, id | UMTX_CONTESTED);
if (owner == UMTX_CONTESTED)
return (0);
@ -289,13 +461,9 @@ _umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
* If we caught a signal, we have retried and now
* exit immediately.
*/
if (error)
if (error || (error = umtxq_queue_me(td, umtx, &uq)) != 0)
return (error);
umtxq_lock(td, umtx);
uq = umtxq_insert(td, umtx);
umtxq_unlock(td, umtx);
/*
* Set the contested bit so that a release in user space
* knows to use the system call for unlock. If this fails
@ -307,9 +475,10 @@ _umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
/* The address was invalid. */
if (old == -1) {
umtxq_lock(td, umtx);
umtx_remove(uq, td, umtx);
/* unlocked by umtx_remove */
umtxq_lock(&uq.uq_key);
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
umtx_key_release(&uq.uq_key);
return (EFAULT);
}
@ -318,46 +487,66 @@ _umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
* and we need to retry or we lost a race to the thread
* unlocking the umtx.
*/
umtxq_lock(td, umtx);
if (old == owner && (td->td_flags & TDF_UMTXWAKEUP) == 0)
error = umtx_sleep(td, umtx, td->td_priority | PCATCH,
"umtx", 0);
else
umtxq_lock(&uq.uq_key);
if (old == owner && (td->td_flags & TDF_UMTXQ)) {
error = umtxq_sleep(td, &uq.uq_key,
td->td_priority | PCATCH | PDROP,
"umtx", timo);
if (td->td_flags & TDF_UMTXQ) {
umtxq_lock(&uq.uq_key);
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
}
} else {
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
error = 0;
umtx_remove(uq, td, umtx);
/* unlocked by umtx_remove */
if (td->td_flags & TDF_UMTXWAKEUP) {
/*
* If we were resumed by umtxq_unlock, we should retry
* to avoid a race.
*/
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_UMTXWAKEUP;
mtx_unlock_spin(&sched_lock);
continue;
}
/*
* If we caught a signal, exit immediately.
*/
if (error)
return (error);
umtx_key_release(&uq.uq_key);
}
return (0);
}
int
_umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
/* struct umtx *umtx */
static int
do_lock(struct thread *td, struct umtx *umtx, long id,
struct timespec *abstime)
{
struct umtx *umtx;
struct timespec ts1, ts2;
struct timeval tv;
int timo, error;
if (abstime == NULL) {
error = _do_lock(td, umtx, id, 0);
} else {
for (;;) {
ts1 = *abstime;
getnanotime(&ts2);
timespecsub(&ts1, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts1);
if (tv.tv_sec < 0) {
error = ETIMEDOUT;
break;
}
timo = tvtohz(&tv);
error = _do_lock(td, umtx, id, timo);
if (error != ETIMEDOUT) {
if (error == ERESTART)
error = EINTR;
break;
}
}
}
return (error);
}
static int
do_unlock(struct thread *td, struct umtx *umtx, long id)
{
struct umtx_key key;
intptr_t owner;
intptr_t old;
int count;
umtx = uap->umtx;
int count, error;
/*
* Make sure we own this mtx.
@ -368,7 +557,7 @@ _umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
if ((owner = fuword(&umtx->u_owner)) == -1)
return (EFAULT);
if ((owner & ~UMTX_CONTESTED) != td->td_tid)
if ((owner & ~UMTX_CONTESTED) != id)
return (EPERM);
/* We should only ever be in here for contested locks */
@ -386,15 +575,20 @@ _umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
if (old != owner)
return (EINVAL);
if ((error = umtx_key_get(td, umtx, &key)) != 0)
return (error);
/*
* At the point, a new thread can lock the umtx before we
* reach here, so contested bit will not be set, if there
* are two or more threads on wait queue, we should set
* contensted bit for them.
*/
count = umtxq_count(td, umtx);
if (count <= 0)
count = umtxq_count(&key);
if (count <= 0) {
umtx_key_release(&key);
return (0);
}
/*
* If there is second thread waiting on umtx, set contested bit,
@ -408,8 +602,10 @@ _umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
owner | UMTX_CONTESTED);
if (old == owner)
break;
if (old == -1)
if (old == -1) {
umtx_key_release(&key);
return (EFAULT);
}
owner = old;
}
/*
@ -417,12 +613,190 @@ _umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
* to wake more threads, that thread will do it when it unlocks
* the umtx.
*/
if ((owner & ~UMTX_CONTESTED) != 0)
if ((owner & ~UMTX_CONTESTED) != 0) {
umtx_key_release(&key);
return (0);
}
}
/* Wake blocked thread. */
umtx_signal(td, umtx);
umtxq_signal(&key);
umtx_key_release(&key);
return (0);
}
static int
do_unlock_and_wait(struct thread *td, struct umtx *umtx, long id, void *uaddr,
struct timespec *abstime)
{
struct umtx_q uq;
intptr_t owner;
intptr_t old;
struct timespec ts1, ts2;
struct timeval tv;
int timo, error = 0;
if (umtx == uaddr)
return (EINVAL);
/*
* Make sure we own this mtx.
*
* XXX Need a {fu,su}ptr this is not correct on arch where
* sizeof(intptr_t) != sizeof(long).
*/
if ((owner = fuword(&umtx->u_owner)) == -1)
return (EFAULT);
if ((owner & ~UMTX_CONTESTED) != id)
return (EPERM);
if ((error = umtxq_queue_me(td, uaddr, &uq)) != 0)
return (error);
old = casuptr((intptr_t *)&umtx->u_owner, id, UMTX_UNOWNED);
if (old == -1) {
umtxq_lock(&uq.uq_key);
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
umtx_key_release(&uq.uq_key);
return (EFAULT);
}
if (old != id) {
error = do_unlock(td, umtx, id);
if (error) {
umtxq_lock(&uq.uq_key);
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
umtx_key_release(&uq.uq_key);
return (error);
}
}
if (abstime == NULL) {
umtxq_lock(&uq.uq_key);
if (td->td_flags & TDF_UMTXQ)
error = umtxq_sleep(td, &uq.uq_key,
td->td_priority | PCATCH, "ucond", 0);
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
if (error == ERESTART)
error = EINTR;
} else {
for (;;) {
ts1 = *abstime;
getnanotime(&ts2);
timespecsub(&ts1, &ts2);
TIMESPEC_TO_TIMEVAL(&tv, &ts1);
if (tv.tv_sec < 0) {
error = ETIMEDOUT;
break;
}
timo = tvtohz(&tv);
umtxq_lock(&uq.uq_key);
if (td->td_flags & TDF_UMTXQ) {
error = umtxq_sleep(td, &uq.uq_key,
td->td_priority | PCATCH,
"ucond", timo);
if (!(td->td_flags & TDF_UMTXQ)) {
umtxq_unlock(&uq.uq_key);
error = 0;
break;
}
if (error != 0 && error != ETIMEDOUT) {
umtxq_unlock(&uq.uq_key);
if (error == ERESTART)
error = EINTR;
break;
}
} else {
umtxq_unlock(&uq.uq_key);
error = 0;
break;
}
}
if (td->td_flags & TDF_UMTXQ) {
umtxq_lock(&uq.uq_key);
umtxq_remove(&uq);
umtxq_unlock(&uq.uq_key);
}
}
umtx_key_release(&uq.uq_key);
return (error);
}
static int
do_wake(struct thread *td, void *uaddr, int broadcast)
{
struct umtx_key key;
int error;
if ((error = umtx_key_get(td, uaddr, &key)) != 0)
return (error);
if (!broadcast)
umtxq_signal(&key);
else
umtxq_broadcast(&key);
umtx_key_release(&key);
return (0);
}
int
_umtx_lock(struct thread *td, struct _umtx_lock_args *uap)
/* struct umtx *umtx */
{
return _do_lock(td, uap->umtx, td->td_tid, 0);
}
int
_umtx_unlock(struct thread *td, struct _umtx_unlock_args *uap)
/* struct umtx *umtx */
{
return do_unlock(td, uap->umtx, td->td_tid);
}
int
_umtx_op(struct thread *td, struct _umtx_op_args *uap)
{
struct timespec abstime;
struct timespec *ts;
int error;
switch(uap->op) {
case UMTX_OP_LOCK:
/* Allow a null timespec (wait forever). */
if (uap->abstime == NULL)
ts = NULL;
else {
error = copyin(uap->abstime, &abstime, sizeof(abstime));
if (error != 0)
return (error);
if (abstime.tv_nsec >= 1000000000 ||
abstime.tv_nsec < 0)
return (EINVAL);
ts = &abstime;
}
return do_lock(td, uap->umtx, uap->id, ts);
case UMTX_OP_UNLOCK:
return do_unlock(td, uap->umtx, uap->id);
case UMTX_OP_UNLOCK_AND_WAIT:
/* Allow a null timespec (wait forever). */
if (uap->abstime == NULL)
ts = NULL;
else {
error = copyin(uap->abstime, &abstime, sizeof(abstime));
if (error != 0)
return (error);
if (abstime.tv_nsec >= 1000000000 ||
abstime.tv_nsec < 0)
return (EINVAL);
ts = &abstime;
}
return do_unlock_and_wait(td, uap->umtx, uap->id,
uap->uaddr, ts);
case UMTX_OP_WAKE:
return do_wake(td, uap->uaddr, uap->id);
default:
return (EINVAL);
}
}

1
sys/kern/syscalls.c
View File

@ -461,4 +461,5 @@ const char *syscallnames[] = {
"getaudit_addr", /* 451 = getaudit_addr */
"setaudit_addr", /* 452 = setaudit_addr */
"auditctl", /* 453 = auditctl */
"_umtx_op", /* 454 = _umtx_op */
};

2
sys/kern/syscalls.master
View File

@ -643,5 +643,7 @@
452 MNOSTD { int setaudit_addr(struct auditinfo_addr \
*auditinfo_addr, u_int length); }
453 MNOSTD { int auditctl(int cmd, char *path); }
454 MSTD { int _umtx_op(struct umtx *umtx, int op, long id, void *uaddr,\
struct timespec *abstime); }
; Please copy any additions and changes to the following compatability tables:
; sys/compat/freebsd32/syscalls.master

4
sys/sys/proc.h
View File

@ -282,7 +282,7 @@ struct thread {
sigset_t td_sigmask; /* (c) Current signal mask. */
sigset_t td_siglist; /* (c) Sigs arrived, not delivered. */
sigset_t *td_waitset; /* (c) Wait set for sigwait. */
TAILQ_ENTRY(thread) td_umtx; /* (c?) Link for when we're blocked. */
struct umtx_q *td_umtxq; /* (c?) Link for when we're blocked. */
volatile u_int td_generation; /* (k) For detection of preemption */
stack_t td_sigstk; /* (k) Stack ptr and on-stack flag. */
int td_kflags; /* (c) Flags for KSE threading. */
@ -345,7 +345,7 @@ struct thread {
#define TDF_NEEDRESCHED 0x00010000 /* Thread needs to yield. */
#define TDF_NEEDSIGCHK 0x00020000 /* Thread may need signal delivery. */
#define TDF_XSIG 0x00040000 /* Thread is exchanging signal under trace */
#define TDF_UMTXWAKEUP 0x00080000 /* Libthr thread must not sleep on a umtx. */
#define TDF_UMTXQ 0x00080000 /* Thread is sleeping on a umtx. */
#define TDF_THRWAKEUP 0x00100000 /* Libthr thread must not suspend itself. */
#define TDF_DBSUSPEND 0x00200000 /* Thread is suspended by debugger */
#define TDF_UNUSED22 0x00400000 /* --available -- */

5
sys/sys/syscall.h
View File

@ -3,7 +3,7 @@
*
* DO NOT EDIT-- this file is automatically generated.
* $FreeBSD$
* created from FreeBSD: src/sys/kern/syscalls.master,v 1.178 2004/10/23 20:00:43 rwatson Exp
* created from FreeBSD: src/sys/kern/syscalls.master,v 1.180 2004/11/25 12:07:28 phk Exp
*/
#define SYS_syscall 0
@ -367,4 +367,5 @@
#define SYS_getaudit_addr 451
#define SYS_setaudit_addr 452
#define SYS_auditctl 453
#define SYS_MAXSYSCALL 454
#define SYS__umtx_op 454
#define SYS_MAXSYSCALL 455

5
sys/sys/syscall.mk
View File

@ -1,7 +1,7 @@
# FreeBSD system call names.
# DO NOT EDIT-- this file is automatically generated.
# $FreeBSD$
# created from FreeBSD: src/sys/kern/syscalls.master,v 1.178 2004/10/23 20:00:43 rwatson Exp
# created from FreeBSD: src/sys/kern/syscalls.master,v 1.180 2004/11/25 12:07:28 phk Exp
MIASM = \
syscall.o \
exit.o \
@ -308,4 +308,5 @@ MIASM = \
setaudit.o \
getaudit_addr.o \
setaudit_addr.o \
auditctl.o
auditctl.o \
_umtx_op.o

10
sys/sys/sysproto.h
View File

@ -3,7 +3,7 @@
*
* DO NOT EDIT-- this file is automatically generated.
* $FreeBSD$
* created from FreeBSD: src/sys/kern/syscalls.master,v 1.178 2004/10/23 20:00:43 rwatson Exp
* created from FreeBSD: src/sys/kern/syscalls.master,v 1.180 2004/11/25 12:07:28 phk Exp
*/
#ifndef _SYS_SYSPROTO_H_
@ -1342,6 +1342,13 @@ struct auditctl_args {
char cmd_l_[PADL_(int)]; int cmd; char cmd_r_[PADR_(int)];
char path_l_[PADL_(char *)]; char * path; char path_r_[PADR_(char *)];
};
struct _umtx_op_args {
char umtx_l_[PADL_(struct umtx *)]; struct umtx * umtx; char umtx_r_[PADR_(struct umtx *)];
char op_l_[PADL_(int)]; int op; char op_r_[PADR_(int)];
char id_l_[PADL_(long)]; long id; char id_r_[PADR_(long)];
char uaddr_l_[PADL_(void *)]; void * uaddr; char uaddr_r_[PADR_(void *)];
char abstime_l_[PADL_(struct timespec *)]; struct timespec * abstime; char abstime_r_[PADR_(struct timespec *)];
};
int nosys(struct thread *, struct nosys_args *);
void sys_exit(struct thread *, struct sys_exit_args *);
int fork(struct thread *, struct fork_args *);
@ -1647,6 +1654,7 @@ int setaudit(struct thread *, struct setaudit_args *);
int getaudit_addr(struct thread *, struct getaudit_addr_args *);
int setaudit_addr(struct thread *, struct setaudit_addr_args *);
int auditctl(struct thread *, struct auditctl_args *);
int _umtx_op(struct thread *, struct _umtx_op_args *);
#ifdef COMPAT_43

54
sys/sys/umtx.h
View File

@ -40,13 +40,23 @@ struct umtx {
void *u_owner; /* Owner of the mutex. */
};
/* op code for _umtx_op */
#define UMTX_OP_LOCK 0
#define UMTX_OP_UNLOCK 1
#define UMTX_OP_UNLOCK_AND_WAIT 2
#define UMTX_OP_WAKE 3
#ifndef _KERNEL
/*
* System calls for acquiring and releasing contested mutexes.
*/
/* deprecated becaues it can only use thread id */
int _umtx_lock(struct umtx *mtx);
/* deprecated becaues it can only use thread id */
int _umtx_unlock(struct umtx *mtx);
int _umtx_op(struct umtx *umtx, int op, long id, void *uaddr,
struct timespec *abstime);
/*
* Standard api. Try uncontested acquire/release and asks the
@ -57,7 +67,7 @@ umtx_lock(struct umtx *umtx, long id)
{
if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
(void *)id) == 0)
if (_umtx_lock(umtx) == -1)
if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0, 0) == -1)
return (errno);
return (0);
}
@ -71,15 +81,53 @@ umtx_trylock(struct umtx *umtx, long id)
return (0);
}
static __inline int
umtx_timedlock(struct umtx *umtx, long id, struct timespec *abstime)
{
if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
(void *)id) == 0)
if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0, abstime) == -1)
return (errno);
return (0);
}
static __inline int
umtx_unlock(struct umtx *umtx, long id)
{
if (atomic_cmpset_rel_ptr(&umtx->u_owner, (void *)id,
(void *)UMTX_UNOWNED) == 0)
if (_umtx_unlock(umtx) == -1)
if (_umtx_op(umtx, UMTX_OP_UNLOCK, id, 0, 0) == -1)
return (errno);
return (0);
}
#endif /* !_KERNEL */
/* Unlock umtx and wait on a user address. */
static __inline int
umtx_wait(struct umtx *umtx, long id, void *uaddr)
{
if (_umtx_op(umtx, UMTX_OP_UNLOCK_AND_WAIT, id, uaddr, 0) == -1)
return (errno);
return (0);
}
static __inline int
umtx_timedwait(struct umtx *umtx, long id, void *uaddr,
struct timespec *abstime)
{
if (_umtx_op(umtx, UMTX_OP_UNLOCK_AND_WAIT, id, uaddr, abstime) == -1)
return (errno);
return (0);
}
/* Wake threads waiting on a user address. */
static __inline int
umtx_wake(void *uaddr, int broadcast)
{
if (_umtx_op(0, UMTX_OP_WAKE, broadcast, uaddr, 0) == -1)
return (errno);
return (0);
}
#endif /* !_KERNEL */
#endif /* !_SYS_UMTX_H_ */