2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * NOTE! This file may be compiled for userland libraries as well as for
29 * $DragonFly: src/sys/kern/lwkt_msgport.c,v 1.8 2003/11/20 06:05:30 dillon Exp $
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
38 #include <sys/rtprio.h>
39 #include <sys/queue.h>
40 #include <sys/sysctl.h>
41 #include <sys/kthread.h>
42 #include <machine/cpu.h>
46 #include <vm/vm_param.h>
47 #include <vm/vm_kern.h>
48 #include <vm/vm_object.h>
49 #include <vm/vm_page.h>
50 #include <vm/vm_map.h>
51 #include <vm/vm_pager.h>
52 #include <vm/vm_extern.h>
53 #include <vm/vm_zone.h>
55 #include <sys/thread2.h>
56 #include <sys/msgport2.h>
58 #include <machine/stdarg.h>
59 #include <machine/ipl.h>
61 #include <machine/smp.h>
66 #include <sys/msgport.h>
67 #include <sys/msgport2.h>
72 /************************************************************************
74 ************************************************************************/
76 static void lwkt_replyport_remote(lwkt_msg_t msg);
77 static void lwkt_putport_remote(lwkt_msg_t msg);
80 lwkt_initmsg_td(lwkt_msg_t msg, thread_t td)
82 lwkt_initmsg(msg, &td->td_msgport, 0);
88 * Send a message asynchronously. This function requests asynchronous
89 * completion and calls lwkt_beginmsg(). If the target port decides to
90 * run the message synchronously this function will automatically queue
91 * the message to the current thread's message queue to present a
92 * consistent interface to the caller.
94 * The message's ms_cmd must be initialized and its ms_flags must be
95 * at least zero'd out. lwkt_sendmsg() will initialize the message's
96 * reply port to the current thread's built-in reply port.
99 lwkt_sendmsg(lwkt_port_t port, lwkt_msg_t msg)
103 msg->ms_flags |= MSGF_ASYNC;
104 msg->ms_flags &= ~(MSGF_REPLY | MSGF_QUEUED);
105 msg->ms_reply_port = &curthread->td_msgport;
106 if ((error = lwkt_beginmsg(port, msg)) != EASYNC) {
107 lwkt_replymsg(msg, error);
114 * Send a message synchronously. This function requests synchronous
115 * completion and calls lwkt_beginmsg(). If the target port decides to
116 * run the message asynchronously this function will block waiting for
117 * the message to complete. Since MSGF_ASYNC is not set the target
118 * will not attempt to queue the reply to a reply port but will simply
119 * wake up anyone waiting on the message.
121 * A synchronous error code is always returned.
123 * The message's ms_cmd must be initialized and its ms_flags must be
124 * at least zero'd out. lwkt_domsg() will initialize the message's
125 * reply port to the current thread's built-in reply port.
128 lwkt_domsg(lwkt_port_t port, lwkt_msg_t msg)
132 msg->ms_flags &= ~(MSGF_ASYNC | MSGF_REPLY | MSGF_QUEUED);
133 msg->ms_reply_port = &curthread->td_msgport;
134 if ((error = lwkt_beginmsg(port, msg)) == EASYNC) {
135 error = lwkt_waitmsg(msg);
140 /************************************************************************
142 ************************************************************************/
147 * Initialize a port for use and assign it to the specified thread.
150 lwkt_init_port(lwkt_port_t port, thread_t td)
152 bzero(port, sizeof(*port));
153 TAILQ_INIT(&port->mp_msgq);
155 port->mp_putport = lwkt_putport;
156 port->mp_waitport = lwkt_waitport;
157 port->mp_replyport = lwkt_replyport;
158 port->mp_abortport = lwkt_abortport;
162 * The rest of the procedures implement the kernel's port functions. Userland
163 * will have a different set of these
171 * This function is typically assigned to the mp_replyport port vector.
173 * The message is being returned to the specified port. The port is
174 * owned by the mp_td thread. If we are on the same cpu as the mp_td
175 * thread we can trivially queue the message to the messageq, otherwise
176 * we have to send an ipi message to the correct cpu. We then schedule
179 * If MSGF_ASYNC is not set we do not bother queueing the message, we
180 * just set the DONE bit.
182 * This inline must be entered with a critical section already held.
183 * Note that the IPIQ callback function (*_remote) is entered with a
184 * critical section already held, and we obtain one in lwkt_replyport().
188 _lwkt_replyport(lwkt_port_t port, lwkt_msg_t msg)
190 thread_t td = port->mp_td;
192 if (td->td_gd == mycpu) {
193 TAILQ_INSERT_TAIL(&port->mp_msgq, msg, ms_node);
194 msg->ms_flags |= MSGF_DONE | MSGF_REPLY | MSGF_QUEUED;
195 if (port->mp_flags & MSGPORTF_WAITING)
198 lwkt_send_ipiq(td->td_gd->gd_cpuid, (ipifunc_t)lwkt_replyport_remote, msg);
204 lwkt_replyport_remote(lwkt_msg_t msg)
206 _lwkt_replyport(msg->ms_reply_port, msg);
210 lwkt_replyport(lwkt_port_t port, lwkt_msg_t msg)
213 if (msg->ms_flags & MSGF_ASYNC) {
214 _lwkt_replyport(port, msg);
216 msg->ms_flags |= MSGF_DONE;
217 if (port->mp_flags & MSGPORTF_WAITING)
218 lwkt_schedule(port->mp_td);
226 * This function is typically assigned to the mp_putport port vector.
228 * Queue a message to the target port and wakeup the thread owning it.
229 * This function always returns EASYNC and may be assigned to a
230 * message port's mp_putport function vector.
232 * You must already be in a critical section when calling
233 * the inline function. The _remote function will be in a critical
234 * section due to being called from the IPI, and lwkt_putport() enters
235 * a critical section.
240 _lwkt_putport(lwkt_port_t port, lwkt_msg_t msg)
242 thread_t td = port->mp_td;
244 if (td->td_gd == mycpu) {
245 TAILQ_INSERT_TAIL(&port->mp_msgq, msg, ms_node);
246 msg->ms_flags |= MSGF_QUEUED;
247 if (port->mp_flags & MSGPORTF_WAITING)
250 msg->ms_target_port = port;
251 lwkt_send_ipiq(td->td_gd->gd_cpuid, (ipifunc_t)lwkt_putport_remote, msg);
257 lwkt_putport_remote(lwkt_msg_t msg)
259 _lwkt_putport(msg->ms_target_port, msg);
263 lwkt_putport(lwkt_port_t port, lwkt_msg_t msg)
266 msg->ms_flags &= ~MSGF_DONE;
267 _lwkt_putport(port, msg);
275 * This function is typically assigned to the mp_abortport port vector.
277 * This vector is typically called via the message's ms_target_port
278 * pointer. It should be noted that ms_target_port may race against
279 * a forwarding operation run on a different cpu. Any implementation
280 * of lwkt_abortport() must deal with potential races by following
281 * the message to the next appropriate port.
283 * This function is a NOP. by defaults message ports have no abort
284 * capabilities. Remember that aborts are always optional so doing
285 * nothing is perfectly reasonable.
288 lwkt_abortport(lwkt_port_t port, lwkt_msg_t msg)
296 * Retrieve the next message from the port's message queue, return NULL
297 * if no messages are pending.
299 * The calling thread MUST own the port.
302 lwkt_getport(lwkt_port_t port)
306 KKASSERT(port->mp_td == curthread);
309 if ((msg = TAILQ_FIRST(&port->mp_msgq)) != NULL) {
310 TAILQ_REMOVE(&port->mp_msgq, msg, ms_node);
311 msg->ms_flags &= ~MSGF_QUEUED;
320 * If msg is NULL, dequeue the next message from the port's message
321 * queue, block until a message is ready. This function never
324 * If msg is non-NULL, block until the requested message has been returned
325 * to the port then dequeue and return it.
327 * Note that the API does not currently support multiple threads waiting
328 * on a port. By virtue of owning the port it is controlled by our
329 * cpu and we can safely manipulate it's contents.
332 lwkt_waitport(lwkt_port_t port, lwkt_msg_t msg)
334 KKASSERT(port->mp_td == curthread);
338 if ((msg = TAILQ_FIRST(&port->mp_msgq)) == NULL) {
339 port->mp_flags |= MSGPORTF_WAITING;
341 lwkt_deschedule_self();
343 } while ((msg = TAILQ_FIRST(&port->mp_msgq)) == NULL);
344 port->mp_flags &= ~MSGPORTF_WAITING;
346 TAILQ_REMOVE(&port->mp_msgq, msg, ms_node);
347 msg->ms_flags &= ~MSGF_QUEUED;
350 * If the message is marked done by not queued it has already been
351 * pulled off the port and returned and we do not have to do anything.
352 * Otherwise we do not own the message have to wait for message
353 * completion. Beware of cpu races if MSGF_DONE is not foudn to be
356 if ((msg->ms_flags & (MSGF_DONE|MSGF_REPLY)) != MSGF_DONE) {
358 * We must own the reply port to safely mess with it's contents.
360 port = msg->ms_reply_port;
361 KKASSERT(port->mp_td == curthread);
364 if ((msg->ms_flags & MSGF_DONE) == 0) {
365 port->mp_flags |= MSGPORTF_WAITING; /* saved by the BGL */
367 lwkt_deschedule_self();
369 } while ((msg->ms_flags & MSGF_DONE) == 0);
370 port->mp_flags &= ~MSGPORTF_WAITING; /* saved by the BGL */
373 * We own the message now.
375 if (msg->ms_flags & MSGF_QUEUED) {
376 msg->ms_flags &= ~MSGF_QUEUED;
377 TAILQ_REMOVE(&port->mp_msgq, msg, ms_node);