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NetBSD/sys/rump/librump/rumpkern/locks.c

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/* $NetBSD: locks.c,v 1.50 2011/01/28 17:04:39 pooka Exp $ */
/*
* Copyright (c) 2007, 2008 Antti Kantee. All Rights Reserved.
*
* Development of this software was supported by the
* Finnish Cultural Foundation.
*
* 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, 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 OR CONTRIBUTORS 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>
__KERNEL_RCSID(0, "$NetBSD: locks.c,v 1.50 2011/01/28 17:04:39 pooka Exp $");
#include <sys/param.h>
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <rump/rumpuser.h>
#include "rump_private.h"
/*
* Simple lockdebug. If it's compiled in, it's always active.
* Currently available only for mtx/rwlock.
*/
#ifdef LOCKDEBUG
#include <sys/lockdebug.h>
static lockops_t mutex_lockops = {
"mutex",
LOCKOPS_SLEEP,
NULL
};
static lockops_t rw_lockops = {
"rwlock",
LOCKOPS_SLEEP,
NULL
};
#define ALLOCK(lock, ops) \
lockdebug_alloc(lock, ops, (uintptr_t)__builtin_return_address(0))
#define FREELOCK(lock) \
lockdebug_free(lock)
#define WANTLOCK(lock, shar, try) \
lockdebug_wantlock(lock, (uintptr_t)__builtin_return_address(0), shar, try)
#define LOCKED(lock, shar) \
lockdebug_locked(lock, NULL, (uintptr_t)__builtin_return_address(0), shar)
#define UNLOCKED(lock, shar) \
lockdebug_unlocked(lock, (uintptr_t)__builtin_return_address(0), shar)
#else
#define ALLOCK(a, b)
#define FREELOCK(a)
#define WANTLOCK(a, b, c)
#define LOCKED(a, b)
#define UNLOCKED(a, b)
#endif
/*
* We map locks to pthread routines. The difference between kernel
* and rumpuser routines is that while the kernel uses static
* storage, rumpuser allocates the object from the heap. This
* indirection is necessary because we don't know the size of
* pthread objects here. It is also beneficial, since we can
* be easily compatible with the kernel ABI because all kernel
* objects regardless of machine architecture are always at least
* the size of a pointer. The downside, of course, is a performance
* penalty.
*/
#define RUMPMTX(mtx) (*(struct rumpuser_mtx **)(mtx))
void
mutex_init(kmutex_t *mtx, kmutex_type_t type, int ipl)
{
CTASSERT(sizeof(kmutex_t) >= sizeof(void *));
rumpuser_mutex_init_kmutex((struct rumpuser_mtx **)mtx);
ALLOCK(mtx, &mutex_lockops);
}
void
mutex_destroy(kmutex_t *mtx)
{
FREELOCK(mtx);
rumpuser_mutex_destroy(RUMPMTX(mtx));
}
void
mutex_enter(kmutex_t *mtx)
{
WANTLOCK(mtx, false, false);
rumpuser_mutex_enter(RUMPMTX(mtx));
LOCKED(mtx, false);
}
__strong_alias(mutex_spin_enter,mutex_enter);
int
mutex_tryenter(kmutex_t *mtx)
{
int rv;
rv = rumpuser_mutex_tryenter(RUMPMTX(mtx));
if (rv) {
WANTLOCK(mtx, false, true);
LOCKED(mtx, false);
}
return rv;
}
void
mutex_exit(kmutex_t *mtx)
{
UNLOCKED(mtx, false);
rumpuser_mutex_exit(RUMPMTX(mtx));
}
__strong_alias(mutex_spin_exit,mutex_exit);
int
mutex_owned(kmutex_t *mtx)
{
return mutex_owner(mtx) == curlwp;
}
struct lwp *
mutex_owner(kmutex_t *mtx)
{
return rumpuser_mutex_owner(RUMPMTX(mtx));
}
#define RUMPRW(rw) (*(struct rumpuser_rw **)(rw))
/* reader/writer locks */
void
rw_init(krwlock_t *rw)
{
CTASSERT(sizeof(krwlock_t) >= sizeof(void *));
rumpuser_rw_init((struct rumpuser_rw **)rw);
ALLOCK(rw, &rw_lockops);
}
void
rw_destroy(krwlock_t *rw)
{
FREELOCK(rw);
rumpuser_rw_destroy(RUMPRW(rw));
}
void
rw_enter(krwlock_t *rw, const krw_t op)
{
WANTLOCK(rw, op == RW_READER, false);
rumpuser_rw_enter(RUMPRW(rw), op == RW_WRITER);
LOCKED(rw, op == RW_READER);
}
int
rw_tryenter(krwlock_t *rw, const krw_t op)
{
int rv;
rv = rumpuser_rw_tryenter(RUMPRW(rw), op == RW_WRITER);
if (rv) {
WANTLOCK(rw, op == RW_READER, true);
LOCKED(rw, op == RW_READER);
}
return rv;
}
void
rw_exit(krwlock_t *rw)
{
#ifdef LOCKDEBUG
bool shared = !rw_write_held(rw);
if (shared)
KASSERT(rw_read_held(rw));
UNLOCKED(rw, shared);
#endif
rumpuser_rw_exit(RUMPRW(rw));
}
/* always fails */
int
rw_tryupgrade(krwlock_t *rw)
{
return 0;
}
void
rw_downgrade(krwlock_t *rw)
{
#ifdef LOCKDEBUG
KASSERT(!rw_write_held(rw));
#endif
/*
* XXX HACK: How we can downgrade re lock in rump properly.
*/
rw_exit(rw);
rw_enter(rw, RW_READER);
return;
}
int
rw_write_held(krwlock_t *rw)
{
return rumpuser_rw_wrheld(RUMPRW(rw));
}
int
rw_read_held(krwlock_t *rw)
{
return rumpuser_rw_rdheld(RUMPRW(rw));
}
int
rw_lock_held(krwlock_t *rw)
{
return rumpuser_rw_held(RUMPRW(rw));
}
/* curriculum vitaes */
#define RUMPCV(cv) (*(struct rumpuser_cv **)(cv))
void
cv_init(kcondvar_t *cv, const char *msg)
{
CTASSERT(sizeof(kcondvar_t) >= sizeof(void *));
rumpuser_cv_init((struct rumpuser_cv **)cv);
}
void
cv_destroy(kcondvar_t *cv)
{
rumpuser_cv_destroy(RUMPCV(cv));
}
static int
docvwait(kcondvar_t *cv, kmutex_t *mtx, struct timespec *ts)
{
struct lwp *l = curlwp;
int rv;
if (__predict_false(l->l_flag & LW_RUMP_DYING)) {
/*
* yield() here, someone might want the cpu
* to set a condition. otherwise we'll just
* loop forever.
*/
yield();
return EINTR;
}
UNLOCKED(mtx, false);
l->l_private = cv;
rv = 0;
if (ts) {
if (rumpuser_cv_timedwait(RUMPCV(cv), RUMPMTX(mtx),
ts->tv_sec, ts->tv_nsec))
rv = EWOULDBLOCK;
} else {
rumpuser_cv_wait(RUMPCV(cv), RUMPMTX(mtx));
}
/*
* Check for DYING. if so, we need to wait here until we
* are allowed to exit.
*/
if (__predict_false(l->l_flag & LW_RUMP_DYING)) {
struct proc *p = l->l_proc;
mutex_exit(mtx); /* drop and retake later */
mutex_enter(p->p_lock);
while (p->p_stat != SDYING) {
/* avoid recursion */
rumpuser_cv_wait(RUMPCV(&p->p_waitcv),
RUMPMTX(p->p_lock));
}
KASSERT(p->p_stat == SDYING);
mutex_exit(p->p_lock);
/* ok, we can exit and remove "reference" to l->private */
mutex_enter(mtx);
rv = EINTR;
}
l->l_private = NULL;
LOCKED(mtx, false);
return rv;
}
void
cv_wait(kcondvar_t *cv, kmutex_t *mtx)
{
if (__predict_false(rump_threads == 0))
panic("cv_wait without threads");
(void) docvwait(cv, mtx, NULL);
}
int
cv_wait_sig(kcondvar_t *cv, kmutex_t *mtx)
{
if (__predict_false(rump_threads == 0))
panic("cv_wait without threads");
return docvwait(cv, mtx, NULL);
}
int
cv_timedwait(kcondvar_t *cv, kmutex_t *mtx, int ticks)
{
struct timespec ts, tick;
extern int hz;
int rv;
if (ticks == 0) {
rv = cv_wait_sig(cv, mtx);
} else {
/*
* XXX: this fetches rump kernel time, but
* rumpuser_cv_timedwait uses host time.
*/
nanotime(&ts);
tick.tv_sec = ticks / hz;
tick.tv_nsec = (ticks % hz) * (1000000000/hz);
timespecadd(&ts, &tick, &ts);
rv = docvwait(cv, mtx, &ts);
}
return rv;
}
__strong_alias(cv_timedwait_sig,cv_timedwait);
void
cv_signal(kcondvar_t *cv)
{
rumpuser_cv_signal(RUMPCV(cv));
}
void
cv_broadcast(kcondvar_t *cv)
{
rumpuser_cv_broadcast(RUMPCV(cv));
}
bool
cv_has_waiters(kcondvar_t *cv)
{
return rumpuser_cv_has_waiters(RUMPCV(cv));
}
/* this is not much of an attempt, but ... */
bool
cv_is_valid(kcondvar_t *cv)
{
return RUMPCV(cv) != NULL;
}
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