/**
* @file
*
* @ingroup rtems_bsd_rtems
*
* @brief TODO.
*/
/*
* Copyright (c) 2011 OPTI Medical. All rights reserved.
*
* OPTI Medical
* 235 Hembree Park Drive
* Roswell, GA 30076
* USA
* <kevin.kirspel@optimedical.com>
*
* 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 AND CONTRIBUTORS ``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.
*/
/* Necessary to obtain some internal functions */
#define __RTEMS_VIOLATE_KERNEL_VISIBILITY__
#include <freebsd/machine/rtems-bsd-config.h>
#include <sys/types.h>
#include <freebsd/sys/param.h>
#include <freebsd/sys/types.h>
#include <freebsd/sys/systm.h>
#include <freebsd/sys/lock.h>
#include <freebsd/sys/rwlock.h>
#include <pthread.h>
#ifndef INVARIANTS
#define _rw_assert(rw, what, file, line)
#endif
static void assert_rw(struct lock_object *lock, int what);
static void lock_rw(struct lock_object *lock, int how);
#ifdef KDTRACE_HOOKS
static int owner_rw(struct lock_object *lock, struct thread **owner);
#endif
static int unlock_rw(struct lock_object *lock);
typedef uint32_t pthread_rwlock_t;
struct lock_class lock_class_rw = {
.lc_name = "rw",
.lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_UPGRADABLE,
.lc_assert = assert_rw,
#ifdef DDB
.lc_ddb_show = db_show_rwlock,
#endif
.lc_lock = lock_rw,
.lc_unlock = unlock_rw,
#ifdef KDTRACE_HOOKS
.lc_owner = owner_rw,
#endif
};
RTEMS_CHAIN_DEFINE_EMPTY(rtems_bsd_rwlock_chain);
void
assert_rw(struct lock_object *lock, int what)
{
rw_assert((struct rwlock *)lock, what);
}
void
lock_rw(struct lock_object *lock, int how)
{
struct rwlock *rw;
rw = (struct rwlock *)lock;
if (how)
rw_wlock(rw);
else
rw_rlock(rw);
}
int
unlock_rw(struct lock_object *lock)
{
struct rwlock *rw;
rw = (struct rwlock *)lock;
rw_assert(rw, RA_LOCKED | LA_NOTRECURSED);
if (rw->rw_lock & RW_LOCK_READ) {
rw_runlock(rw);
return (0);
} else {
rw_wunlock(rw);
return (1);
}
}
#ifdef KDTRACE_HOOKS
int
owner_rw(struct lock_object *lock, struct thread **owner)
{
struct rwlock *rw = (struct rwlock *)lock;
uintptr_t x = rw->rw_lock;
*owner = rw_wowner(rw);
return ((x & RW_LOCK_READ) != 0 ? (RW_READERS(x) != 0) :
(*owner != NULL));
}
#endif
void
rw_init_flags(struct rwlock *rw, const char *name, int opts)
{
struct lock_class *class;
int i;
pthread_rwlock_t lock;
int iret;
if ((opts & RW_RECURSE) != 0) {
/* FIXME */
}
class = &lock_class_rw;
/* Check for double-init and zero object. */
KASSERT(!lock_initalized(&rw->lock_object), ("lock \"%s\" %p already initialized", name, rw->lock_object));
/* Look up lock class to find its index. */
for (i = 0; i < LOCK_CLASS_MAX; i++)
{
if (lock_classes[i] == class)
{
rw->lock_object.lo_flags = i << LO_CLASSSHIFT;
break;
}
}
KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class));
iret = pthread_rwlock_init( &lock, NULL );
BSD_ASSERT( iret == 0 );
rw->lock_object.lo_name = name;
rw->lock_object.lo_flags |= LO_INITIALIZED;
rw->lock_object.lo_id = lock;
rtems_chain_append(&rtems_bsd_rwlock_chain, &rw->lock_object.lo_node);
}
void
rw_destroy(struct rwlock *rw)
{
int iret;
pthread_rwlock_destroy( rw->lock_object.lo_id );
BSD_ASSERT( iret == 0 );
rtems_chain_extract( &rw->lock_object.lo_node );
rw->lock_object.lo_id = 0;
rw->lock_object.lo_flags &= ~LO_INITIALIZED;
}
void
rw_sysinit(void *arg)
{
struct rw_args *args = arg;
rw_init(args->ra_rw, args->ra_desc);
}
void
rw_sysinit_flags(void *arg)
{
struct rw_args_flags *args = arg;
rw_init_flags(args->ra_rw, args->ra_desc, args->ra_flags);
}
int
rw_wowned(struct rwlock *rw)
{
Objects_Locations location;
Semaphore_Control *sema = _Semaphore_Get(rw->lock_object.lo_id, &location);
if (location == OBJECTS_LOCAL && !_Attributes_Is_counting_semaphore(sema->attribute_set)) {
int owned = sema->Core_control.mutex.holder_id == rtems_task_self();
_Thread_Enable_dispatch();
return owned;
} else {
_Thread_Enable_dispatch();
BSD_PANIC("unexpected semaphore location or attributes");
}
}
void
_rw_wlock(struct rwlock *rw, const char *file, int line)
{
int iret;
pthread_rwlock_wrlock( &rw->lock_object.lo_id );
BSD_ASSERT( iret == 0 );
return 0;
}
int
_rw_try_wlock(struct rwlock *rw, const char *file, int line)
{
int iret;
iret = pthread_rwlock_trywrlock( &rw->lock_object.lo_id );
if (iret == 0) {
return 1;
} else {
return 0;
}
}
void
_rw_wunlock(struct rwlock *rw, const char *file, int line)
{
int iret;
iret = pthread_rwlock_unlock( &rw->lock_object.lo_id );
BSD_ASSERT( iret == 0 );
}
void
_rw_rlock(struct rwlock *rw, const char *file, int line)
{
int iret;
iret = pthread_rwlock_rdlock( &rw->lock_object.lo_id );
BSD_ASSERT( iret == 0 );
}
int
_rw_try_rlock(struct rwlock *rw, const char *file, int line)
{
int iret;
iret = pthread_rwlock_tryrdlock( &rw->lock_object.lo_id );
if (iret == 0) {
return 1;
} else {
return 0;
}
}
void
_rw_runlock(struct rwlock *rw, const char *file, int line)
{
int iret;
iret = pthread_rwlock_unlock( &rw->lock_object.lo_id );
BSD_ASSERT( iret == 0 );
}
/*
* Attempt to do a non-blocking upgrade from a read lock to a write
* lock. This will only succeed if this thread holds a single read
* lock. Returns true if the upgrade succeeded and false otherwise.
*/
int
_rw_try_upgrade(struct rwlock *rw, const char *file, int line)
{
return 0; /* XXX */
}
/*
* Downgrade a write lock into a single read lock.
*/
void
_rw_downgrade(struct rwlock *rw, const char *file, int line)
{
/* XXX */
}
#ifdef INVARIANT_SUPPORT
#ifndef INVARIANTS
#undef _rw_assert
#endif
/*
* In the non-WITNESS case, rw_assert() can only detect that at least
* *some* thread owns an rlock, but it cannot guarantee that *this*
* thread owns an rlock.
*/
void
_rw_assert(struct rwlock *rw, int what, const char *file, int line)
{
if (panicstr != NULL)
return;
switch (what) {
case RA_LOCKED:
case RA_LOCKED | RA_RECURSED:
case RA_LOCKED | RA_NOTRECURSED:
case RA_RLOCKED:
#ifdef WITNESS
witness_assert(&rw->lock_object, what, file, line);
#else
/*
* If some other thread has a write lock or we have one
* and are asserting a read lock, fail. Also, if no one
* has a lock at all, fail.
*/
if (rw->rw_lock == RW_UNLOCKED ||
(!(rw->rw_lock & RW_LOCK_READ) && (what == RA_RLOCKED ||
rw_wowner(rw) != curthread)))
panic("Lock %s not %slocked @ %s:%d\n",
rw->lock_object.lo_name, (what == RA_RLOCKED) ?
"read " : "", file, line);
if (!(rw->rw_lock & RW_LOCK_READ)) {
if (rw_recursed(rw)) {
if (what & RA_NOTRECURSED)
panic("Lock %s recursed @ %s:%d\n",
rw->lock_object.lo_name, file,
line);
} else if (what & RA_RECURSED)
panic("Lock %s not recursed @ %s:%d\n",
rw->lock_object.lo_name, file, line);
}
#endif
break;
case RA_WLOCKED:
case RA_WLOCKED | RA_RECURSED:
case RA_WLOCKED | RA_NOTRECURSED:
if (rw_wowner(rw) != curthread)
panic("Lock %s not exclusively locked @ %s:%d\n",
rw->lock_object.lo_name, file, line);
if (rw_recursed(rw)) {
if (what & RA_NOTRECURSED)
panic("Lock %s recursed @ %s:%d\n",
rw->lock_object.lo_name, file, line);
} else if (what & RA_RECURSED)
panic("Lock %s not recursed @ %s:%d\n",
rw->lock_object.lo_name, file, line);
break;
case RA_UNLOCKED:
#ifdef WITNESS
witness_assert(&rw->lock_object, what, file, line);
#else
/*
* If we hold a write lock fail. We can't reliably check
* to see if we hold a read lock or not.
*/
if (rw_wowner(rw) == curthread)
panic("Lock %s exclusively locked @ %s:%d\n",
rw->lock_object.lo_name, file, line);
#endif
break;
default:
panic("Unknown rw lock assertion: %d @ %s:%d", what, file,
line);
}
}
#endif /* INVARIANT_SUPPORT */