kthread abstraction from NetBSD, implemented with our rfork

1 files changed, 190 insertions, 0 deletions

diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
new file mode 100644
index 00000000000..d9cd931b537
--- /dev/null
+++ b/sys/kern/kern_kthread.c
@@ -0,0 +1,190 @@
+/*	$OpenBSD: kern_kthread.c,v 1.1 1999/01/11 01:37:13 niklas Exp $	*/
+/*	$NetBSD: kern_kthread.c,v 1.3 1998/12/22 21:21:36 kleink Exp $	*/
+
+/*-
+ * Copyright (c) 1998 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
+ * NASA Ames Research Center.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the NetBSD
+ *	Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/kthread.h>
+#include <sys/proc.h>
+#include <sys/wait.h>
+#include <sys/malloc.h>
+#include <sys/queue.h>
+
+/*
+ * note that stdarg.h and the ansi style va_start macro is used for both
+ * ansi and traditional c complers.
+ * XXX: this requires that stdarg.h define: va_alist and va_dcl
+ */
+#include <machine/stdarg.h>
+
+/*
+ * Fork a kernel thread.  Any process can request this to be done.
+ * The VM space and limits, etc. will be shared with proc0.
+ */
+int
+#if __STDC__
+kthread_create(void (*func)(void *), void *arg,
+    struct proc **newpp, const char *fmt, ...)
+#else
+kthread_create(func, arg, newpp, fmt, va_alist)
+	void (*func) __P((void *));
+	void *arg;
+	struct proc **newpp;
+	const char *fmt;
+	va_dcl
+#endif
+{
+	struct proc *p2;
+	register_t rv[2];
+	int error;
+	va_list ap;
+
+	/*
+	 * First, create the new process.  Share the memory, copy file
+	 * descriptors and don't leave the exit status around for the
+	 * parent to wait for.
+	 */
+	error = fork1(&proc0, ISRFORK, RFPROC | RFMEM | RFFDG | RFNOWAIT, rv);
+	if (error)
+		return (error);
+
+#ifdef cpu_set_init_frame			/* XXX should go away */
+	if (rv[1]) {
+		/*
+		 * Now in child.
+		 */
+		func(arg);
+		return (0);
+	}
+#endif
+
+	p2 = pfind(rv[0]);
+
+#ifndef cpu_set_init_frame			/* XXX should go away */
+	/* Arrange for it to start at the specified function. */
+	cpu_set_kpc(p2, func, arg);
+#endif
+
+	/*
+	 * Mark it as a system process and not a candidate for
+	 * swapping.
+	 */
+	p2->p_flag |= P_INMEM | P_SYSTEM;	/* XXX */
+
+	/* Name it as specified. */
+	va_start(ap, fmt);
+	vsprintf(p2->p_comm, fmt, ap);
+	va_end(ap);
+
+	/* All done! */
+	if (newpp != NULL)
+		*newpp = p2;
+	return (0);
+}
+
+/*
+ * Cause a kernel thread to exit.  Assumes the exiting thread is the
+ * current context.
+ */
+void
+kthread_exit(ecode)
+	int ecode;
+{
+
+	/*
+	 * XXX What do we do with the exit code?  Should we even bother
+	 * XXX with it?  The parent (proc0) isn't going to do much with
+	 * XXX it.
+	 */
+	if (ecode != 0)
+		printf("WARNING: thread `%s' (%d) exits with status %d\n",
+		    curproc->p_comm, curproc->p_pid, ecode);
+
+	exit1(curproc, W_EXITCODE(ecode, 0));
+
+	/*
+	 * XXX Fool the compiler.  Making exit1() __noreturn__ is a can
+	 * XXX of worms right now.
+	 */
+	for (;;);
+}
+
+struct kthread_q {
+	SIMPLEQ_ENTRY(kthread_q) kq_q;
+	void (*kq_func) __P((void *));
+	void *kq_arg;
+};
+
+SIMPLEQ_HEAD(, kthread_q) kthread_q = SIMPLEQ_HEAD_INITIALIZER(kthread_q);
+
+/*
+ * Defer the creation of a kernel thread.  Once the standard kernel threads
+ * and processes have been created, this queue will be run to callback to
+ * the caller to create threads for e.g. file systems and device drivers.
+ */
+void
+kthread_create_deferred(func, arg)
+	void (*func) __P((void *));
+	void *arg;
+{
+	struct kthread_q *kq;
+
+	kq = malloc(sizeof(*kq), M_TEMP, M_NOWAIT);
+	if (kq == NULL)
+		panic("unable to allocate kthread_q");
+	memset(kq, 0, sizeof(*kq));
+
+	kq->kq_func = func;
+	kq->kq_arg = arg;
+
+	SIMPLEQ_INSERT_TAIL(&kthread_q, kq, kq_q);
+}
+
+void
+kthread_run_deferred_queue()
+{
+	struct kthread_q *kq;
+
+	while ((kq = SIMPLEQ_FIRST(&kthread_q)) != NULL) {
+		SIMPLEQ_REMOVE_HEAD(&kthread_q, kq, kq_q);
+		(*kq->kq_func)(kq->kq_arg);
+		free(kq, M_TEMP);
+	}
+}