/**
* @file
*
* @ingroup rtems_bsd_rtems
*
* @brief TODO.
*/
/*
* Copyright (c) 2009-2014 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-support.h>
#include <rtems/score/objectimpl.h>
#include <rtems/rtems/attrimpl.h>
#include <rtems/rtems/semimpl.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/sx.h>
#ifndef INVARIANTS
#define _sx_assert(sx, what, file, line)
#endif
static void assert_sx(struct lock_object *lock, int what);
static void lock_sx(struct lock_object *lock, int how);
#ifdef KDTRACE_HOOKS
static int owner_sx(struct lock_object *lock, struct thread **owner);
#endif
static int unlock_sx(struct lock_object *lock);
struct lock_class lock_class_sx = {
.lc_name = "sx",
.lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_RECURSABLE | LC_UPGRADABLE,
.lc_assert = assert_sx,
#ifdef DDB
.lc_ddb_show = db_show_sx,
#endif
.lc_lock = lock_sx,
.lc_unlock = unlock_sx,
#ifdef KDTRACE_HOOKS
.lc_owner = owner_sx,
#endif
};
RTEMS_CHAIN_DEFINE_EMPTY(rtems_bsd_sx_chain);
void
assert_sx(struct lock_object *lock, int what)
{
sx_assert((struct sx *)lock, what);
}
void
lock_sx(struct lock_object *lock, int how)
{
struct sx *sx;
sx = (struct sx *)lock;
if (how)
sx_xlock(sx);
else
sx_slock(sx);
}
int
unlock_sx(struct lock_object *lock)
{
struct sx *sx;
sx = (struct sx *)lock;
sx_assert(sx, SA_LOCKED | SA_NOTRECURSED);
if (sx_xlocked(sx)) {
sx_xunlock(sx);
return (1);
} else {
sx_sunlock(sx);
return (0);
}
}
#ifdef KDTRACE_HOOKS
int
owner_sx(struct lock_object *lock, struct thread **owner)
{
struct sx *sx = (struct sx *)lock;
uintptr_t x = sx->sx_lock;
*owner = (struct thread *)SX_OWNER(x);
return ((x & SX_LOCK_SHARED) != 0 ? (SX_SHARERS(x) != 0) :
(*owner != NULL));
}
#endif
void
sx_sysinit(void *arg)
{
struct sx_args *sargs = arg;
sx_init(sargs->sa_sx, sargs->sa_desc);
}
void
sx_init_flags(struct sx *sx, const char *description, int opts)
{
struct lock_class *class;
int i;
rtems_status_code sc = RTEMS_SUCCESSFUL;
rtems_id id = RTEMS_ID_NONE;
rtems_attribute attr = RTEMS_LOCAL | RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE;
if ((opts & SX_RECURSE) != 0) {
/* FIXME */
}
class = &lock_class_sx;
/* Check for double-init and zero object. */
KASSERT(!lock_initalized(&sx->lock_object), ("lock \"%s\" %p already initialized", name, sx->lock_object));
/* Look up lock class to find its index. */
for (i = 0; i < LOCK_CLASS_MAX; i++)
{
if (lock_classes[i] == class)
{
sx->lock_object.lo_flags = i << LO_CLASSSHIFT;
break;
}
}
KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class));
sc = rtems_semaphore_create(
rtems_build_name( '_', 'S', 'X', ' '),
1,
attr,
0,
&id
);
BSD_ASSERT_SC(sc);
sx->lock_object.lo_name = description;
sx->lock_object.lo_flags |= LO_INITIALIZED;
sx->lock_object.lo_id = id;
rtems_chain_append(&rtems_bsd_sx_chain, &sx->lock_object.lo_node);
}
void
sx_destroy(struct sx *sx)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
sc = rtems_semaphore_delete( sx->lock_object.lo_id);
BSD_ASSERT_SC(sc);
rtems_chain_extract(&sx->lock_object.lo_node);
sx->lock_object.lo_id = 0;
sx->lock_object.lo_flags &= ~LO_INITIALIZED;
}
int
_sx_xlock(struct sx *sx, int opts, const char *file, int line)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
#warning "SX_INTERRUPTIBLE NOT SUPPORTED YET"
/* BSD_ASSERT((opts & SX_INTERRUPTIBLE) == 0); */
BSD_ASSERT(!rtems_interrupt_is_in_progress());
sc = rtems_semaphore_obtain( sx->lock_object.lo_id, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
BSD_ASSERT_SC(sc);
return 0;
}
int
_sx_try_xlock(struct sx *sx, const char *file, int line)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
sc = rtems_semaphore_obtain( sx->lock_object.lo_id, RTEMS_NO_WAIT, 0);
if (sc == RTEMS_SUCCESSFUL) {
return 1;
} else if (sc == RTEMS_UNSATISFIED) {
return 0;
} else {
BSD_ASSERT_SC(sc);
return 0;
}
}
void
_sx_xunlock(struct sx *sx, const char *file, int line)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
sc = rtems_semaphore_release( sx->lock_object.lo_id);
BSD_ASSERT_SC(sc);
}
int
_sx_try_upgrade(struct sx *sx, const char *file, int line)
{
return 1;
}
void
_sx_downgrade(struct sx *sx, const char *file, int line)
{
/* Do nothing */
}
#ifdef INVARIANT_SUPPORT
#ifndef INVARIANTS
#undef _sx_assert
#endif
/*
* In the non-WITNESS case, sx_assert() can only detect that at least
* *some* thread owns an slock, but it cannot guarantee that *this*
* thread owns an slock.
*/
void
_sx_assert(struct sx *sx, int what, const char *file, int line)
{
#ifndef WITNESS
int slocked = 0;
#endif
if (panicstr != NULL)
return;
switch (what) {
case SA_SLOCKED:
case SA_SLOCKED | SA_NOTRECURSED:
case SA_SLOCKED | SA_RECURSED:
#ifndef WITNESS
slocked = 1;
/* FALLTHROUGH */
#endif
case SA_LOCKED:
case SA_LOCKED | SA_NOTRECURSED:
case SA_LOCKED | SA_RECURSED:
#ifdef WITNESS
witness_assert(&sx->lock_object, what, file, line);
#else
/*
* If some other thread has an exclusive lock or we
* have one and are asserting a shared lock, fail.
* Also, if no one has a lock at all, fail.
*/
if (sx->sx_lock == SX_LOCK_UNLOCKED ||
(!(sx->sx_lock & SX_LOCK_SHARED) && (slocked ||
sx_xholder(sx) != curthread)))
panic("Lock %s not %slocked @ %s:%d\n",
sx->lock_object.lo_name, slocked ? "share " : "",
file, line);
if (!(sx->sx_lock & SX_LOCK_SHARED)) {
if (sx_recursed(sx)) {
if (what & SA_NOTRECURSED)
panic("Lock %s recursed @ %s:%d\n",
sx->lock_object.lo_name, file,
line);
} else if (what & SA_RECURSED)
panic("Lock %s not recursed @ %s:%d\n",
sx->lock_object.lo_name, file, line);
}
#endif
break;
case SA_XLOCKED:
case SA_XLOCKED | SA_NOTRECURSED:
case SA_XLOCKED | SA_RECURSED:
if (sx_xholder(sx) != curthread)
panic("Lock %s not exclusively locked @ %s:%d\n",
sx->lock_object.lo_name, file, line);
if (sx_recursed(sx)) {
if (what & SA_NOTRECURSED)
panic("Lock %s recursed @ %s:%d\n",
sx->lock_object.lo_name, file, line);
} else if (what & SA_RECURSED)
panic("Lock %s not recursed @ %s:%d\n",
sx->lock_object.lo_name, file, line);
break;
case SA_UNLOCKED:
#ifdef WITNESS
witness_assert(&sx->lock_object, what, file, line);
#else
/*
* If we hold an exclusve lock fail. We can't
* reliably check to see if we hold a shared lock or
* not.
*/
if (sx_xholder(sx) == curthread)
panic("Lock %s exclusively locked @ %s:%d\n",
sx->lock_object.lo_name, file, line);
#endif
break;
default:
panic("Unknown sx lock assertion: %d @ %s:%d", what, file,
line);
}
}
#endif /* INVARIANT_SUPPORT */
int
sx_xlocked(struct sx *sx)
{
Objects_Locations location;
Semaphore_Control *sema = _Semaphore_Get(sx->lock_object.lo_id, &location);
if (location == OBJECTS_LOCAL && !_Attributes_Is_counting_semaphore(sema->attribute_set)) {
int xlocked = sema->Core_control.mutex.holder == _Thread_Executing;
_Thread_Enable_dispatch();
return xlocked;
} else {
_Thread_Enable_dispatch();
BSD_PANIC("unexpected semaphore location or attributes");
}
}
