/**
* @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>
*
* Copyright (c) 2013 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* 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.
*/
#include <machine/rtems-bsd-kernel-space.h>
#include <machine/rtems-bsd-thread.h>
#include <machine/rtems-bsd-support.h>
#include <rtems.h>
#include <rtems/bsd/sys/param.h>
#include <rtems/bsd/sys/types.h>
#include <sys/systm.h>
#include <rtems/bsd/sys/lock.h>
#include <sys/rwlock.h>
#include <sys/mutex.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);
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)
{
int flags;
rtems_status_code sc;
rtems_id id;
rtems_attribute attr = RTEMS_LOCAL | RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_INHERIT_PRIORITY;
flags = LO_UPGRADABLE;
if (opts & RW_RECURSE)
flags |= LO_RECURSABLE;
lock_init(&rw->lock_object, &lock_class_rw, name, NULL, flags);
sc = rtems_semaphore_create(
rtems_build_name('_', '_', 'R', 'W'),
1,
attr,
BSD_TASK_PRIORITY_RESOURCE_OWNER,
&id
);
BSD_ASSERT_SC(sc);
rw->lock_object.lo_id = id;
rtems_chain_append(&rtems_bsd_rwlock_chain, &rw->lock_object.lo_node);
}
void
rw_destroy(struct rwlock *rw)
{
mtx_destroy((struct mtx *) rw);
}
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)
{
return mtx_owned((struct mtx *) rw);
}
void
_rw_wlock(struct rwlock *rw, const char *file, int line)
{
_mtx_lock_flags((struct mtx *) rw, 0, file, line);
}
int
_rw_try_wlock(struct rwlock *rw, const char *file, int line)
{
return _mtx_trylock((struct mtx *) rw, 0, file, line);
}
void
_rw_wunlock(struct rwlock *rw, const char *file, int line)
{
_mtx_unlock_flags((struct mtx *) rw, 0, file, line);
}
void
_rw_rlock(struct rwlock *rw, const char *file, int line)
{
_mtx_lock_flags((struct mtx *) rw, 0, file, line);
}
int
_rw_try_rlock(struct rwlock *rw, const char *file, int line)
{
return _mtx_trylock((struct mtx *) rw, 0, file, line);
}
void
_rw_runlock(struct rwlock *rw, const char *file, int line)
{
_mtx_unlock_flags((struct mtx *) rw, 0, file, line);
}
int
_rw_try_upgrade(struct rwlock *rw, const char *file, int line)
{
return 1;
}
void
_rw_downgrade(struct rwlock *rw, const char *file, int line)
{
/* Nothing to do */
}
#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 */
