/*
* Copyright (c) 2006 Ondrej Palkovsky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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 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.
*/
#ifndef _LIBC_PRIVATE_FIBRIL_H_
#define _LIBC_PRIVATE_FIBRIL_H_
#include <adt/list.h>
#include <context.h>
#include <tls.h>
#include <fibril.h>
#include <ipc/common.h>
#include "./futex.h"
typedef struct {
fibril_t *fibril;
} fibril_event_t;
#define FIBRIL_EVENT_INIT ((fibril_event_t) {0})
struct fibril {
// XXX: The first two fields must not move (for taskdump).
link_t all_link;
context_t ctx;
link_t link;
void *stack;
size_t stack_size;
void *arg;
errno_t (*func)(void *);
tcb_t *tcb;
fibril_t *clean_after_me;
errno_t retval;
fibril_t *thread_ctx;
bool is_running : 1;
bool is_writer : 1;
/* In some places, we use fibril structs that can't be freed. */
bool is_freeable : 1;
/* Debugging stuff. */
int rmutex_locks;
fibril_owner_info_t *waits_for;
fibril_event_t *sleep_event;
};
extern fibril_t *fibril_alloc(void);
extern void fibril_setup(fibril_t *);
extern void fibril_teardown(fibril_t *f);
extern fibril_t *fibril_self(void);
extern void __fibrils_init(void);
extern void __fibrils_fini(void);
extern void fibril_wait_for(fibril_event_t *);
extern errno_t fibril_wait_timeout(fibril_event_t *, const struct timespec *);
extern void fibril_notify(fibril_event_t *);
extern errno_t fibril_ipc_wait(ipc_call_t *, const struct timespec *);
extern void fibril_ipc_poke(void);
/**
* "Restricted" fibril mutex.
*
* Similar to `fibril_mutex_t`, but has a set of restrictions placed on its
* use. Within a rmutex critical section, you
* - may not use any other synchronization primitive,
* save for another `fibril_rmutex_t`. This includes nonblocking
* operations like cvar signal and mutex unlock, unless otherwise
* specified.
* - may not read IPC messages
* - may not start a new thread/fibril
* (creating fibril without starting is fine)
*
* Additionally, locking with a timeout is not possible on this mutex,
* and there is no associated condition variable type.
* This is a design constraint, not a lack of implementation effort.
*/
typedef struct {
// TODO: At this point, this is just silly handwaving to hide current
// futex use behind a fibril based abstraction. Later, the imple-
// mentation will change, but the restrictions placed on this type
// will allow it to be simpler and faster than a regular mutex.
// There might also be optional debug checking of the assumptions.
//
// Note that a consequence of the restrictions is that if we are
// running on a single thread, no other fibril can ever get to run
// while a fibril has a rmutex locked. That means that for
// single-threaded programs, we can reduce all rmutex locks and
// unlocks to simple branches on a global bool variable.
futex_t futex;
} fibril_rmutex_t;
extern errno_t fibril_rmutex_initialize(fibril_rmutex_t *);
extern void fibril_rmutex_destroy(fibril_rmutex_t *);
extern void fibril_rmutex_lock(fibril_rmutex_t *);
extern bool fibril_rmutex_trylock(fibril_rmutex_t *);
extern void fibril_rmutex_unlock(fibril_rmutex_t *);
#endif