Module Name:    src
Committed By:   riastradh
Date:           Sun Dec 19 01:34:57 UTC 2021

Modified Files:
        src/sys/external/bsd/drm2/include/linux: stop_machine.h
        src/sys/external/bsd/drm2/linux: files.drmkms_linux
Added Files:
        src/sys/external/bsd/drm2/linux: linux_stop_machine.c

Log Message:
Draft stop_machine. Hope the callback runs quickly under splhigh...


To generate a diff of this commit:
cvs rdiff -u -r1.1 -r1.2 \
    src/sys/external/bsd/drm2/include/linux/stop_machine.h
cvs rdiff -u -r1.21 -r1.22 src/sys/external/bsd/drm2/linux/files.drmkms_linux
cvs rdiff -u -r0 -r1.1 src/sys/external/bsd/drm2/linux/linux_stop_machine.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/external/bsd/drm2/include/linux/stop_machine.h
diff -u src/sys/external/bsd/drm2/include/linux/stop_machine.h:1.1 src/sys/external/bsd/drm2/include/linux/stop_machine.h:1.2
--- src/sys/external/bsd/drm2/include/linux/stop_machine.h:1.1	Sun Dec 19 00:31:27 2021
+++ src/sys/external/bsd/drm2/include/linux/stop_machine.h	Sun Dec 19 01:34:57 2021
@@ -0,0 +1,41 @@
+/*	$NetBSD: stop_machine.h,v 1.2 2021/12/19 01:34:57 riastradh Exp $	*/
+
+/*-
+ * Copyright (c) 2018 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Taylor R. Campbell.
+ *
+ * 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 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.
+ */
+
+#ifndef	_LINUX_STOP_MACHINE_H_
+#define	_LINUX_STOP_MACHINE_H_
+
+#define	stop_machine		linux_stop_machine
+
+struct kcpuset;
+
+void	stop_machine(int (*)(void *), void *, const struct kcpuset *);
+
+#endif	/* _LINUX_STOP_MACHINE_H_ */

Index: src/sys/external/bsd/drm2/linux/files.drmkms_linux
diff -u src/sys/external/bsd/drm2/linux/files.drmkms_linux:1.21 src/sys/external/bsd/drm2/linux/files.drmkms_linux:1.22
--- src/sys/external/bsd/drm2/linux/files.drmkms_linux:1.21	Sun Dec 19 01:33:18 2021
+++ src/sys/external/bsd/drm2/linux/files.drmkms_linux	Sun Dec 19 01:34:57 2021
@@ -1,4 +1,4 @@
-#       $NetBSD: files.drmkms_linux,v 1.21 2021/12/19 01:33:18 riastradh Exp $
+#       $NetBSD: files.drmkms_linux,v 1.22 2021/12/19 01:34:57 riastradh Exp $
 
 define	drmkms_linux: i2cexec, i2c_bitbang
 
@@ -17,6 +17,7 @@ file	external/bsd/drm2/linux/linux_modul
 file	external/bsd/drm2/linux/linux_pci.c		drmkms_linux
 file	external/bsd/drm2/linux/linux_reservation.c	drmkms_linux
 file	external/bsd/drm2/linux/linux_srcu.c		drmkms_linux
+file	external/bsd/drm2/linux/linux_stop_machine.c	drmkms_linux
 file	external/bsd/drm2/linux/linux_wait_bit.c	drmkms_linux
 file	external/bsd/drm2/linux/linux_writecomb.c	drmkms_linux
 file	external/bsd/drm2/linux/linux_ww_mutex.c	drmkms_linux

Added files:

Index: src/sys/external/bsd/drm2/linux/linux_stop_machine.c
diff -u /dev/null src/sys/external/bsd/drm2/linux/linux_stop_machine.c:1.1
--- /dev/null	Sun Dec 19 01:34:57 2021
+++ src/sys/external/bsd/drm2/linux/linux_stop_machine.c	Sun Dec 19 01:34:57 2021
@@ -0,0 +1,90 @@
+/*	$NetBSD: linux_stop_machine.c,v 1.1 2021/12/19 01:34:57 riastradh Exp $	*/
+
+/*-
+ * Copyright (c) 2018 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Taylor R. Campbell.
+ *
+ * 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 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/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: linux_stop_machine.c,v 1.1 2021/12/19 01:34:57 riastradh Exp $");
+
+#include <sys/atomic.h>
+#include <sys/intr.h>
+#include <sys/lock.h>
+#include <sys/systm.h>
+#include <sys/xcall.h>
+
+#include <linux/stop_machine.h>
+
+struct stop_machine {
+	int			(*callback)(void *);
+	void			*cookie;
+	volatile unsigned	ncpu;
+	volatile bool		done;
+};
+
+static void
+stop_machine_xcall(void *a, void *b)
+{
+	struct stop_machine *S = a;
+	int s;
+
+	/* Block all activity on this CPU.  */
+	s = splhigh();
+
+	/* Note that we're ready, and see whether we're the chosen one.  */
+	if (atomic_dec_uint_nv(&S->ncpu) != 0) {
+		/* Not the chosen one.  Wait until done.  */
+		while (!S->done)
+			SPINLOCK_BACKOFF_HOOK;
+		goto out;
+	}
+
+	/* It's time.  Call the callback.  */
+	S->callback(S->cookie);
+
+	/* Notify everyone else that we're done.  */
+	S->done = true;
+
+	/* Allow activity again.  */
+out:	splx(s);
+}
+
+void
+stop_machine(int (*callback)(void *), void *cookie, const struct kcpuset *cpus)
+{
+	struct stop_machine stop, *S = &stop;
+
+	KASSERT(cpus == NULL);	/* not implemented */
+
+	S->callback = callback;
+	S->cookie = cookie;
+	S->ncpu = ncpu;		/* XXX cpu hotplug */
+	S->done = false;
+
+	xc_wait(xc_broadcast(0, stop_machine_xcall, &S, NULL));
+}

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