[src/trunk]: src/sys/external/bsd/drm2/linux Draft stop_machine. Hope the cal...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3ac3a176bc53
branches:  trunk
changeset: 1028004:3ac3a176bc53
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 01:34:57 2021 +0000

description:
Draft stop_machine. Hope the callback runs quickly under splhigh...

diffstat:

 sys/external/bsd/drm2/include/linux/stop_machine.h |  41 ++++++++++
 sys/external/bsd/drm2/linux/files.drmkms_linux     |   3 +-
 sys/external/bsd/drm2/linux/linux_stop_machine.c   |  90 ++++++++++++++++++++++
 3 files changed, 133 insertions(+), 1 deletions(-)

diffs (156 lines):

diff -r 840c27b024ff -r 3ac3a176bc53 sys/external/bsd/drm2/include/linux/stop_machine.h
--- a/sys/external/bsd/drm2/include/linux/stop_machine.h        Sun Dec 19 01:34:46 2021 +0000
+++ b/sys/external/bsd/drm2/include/linux/stop_machine.h        Sun Dec 19 01:34:57 2021 +0000
@@ -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_ */
diff -r 840c27b024ff -r 3ac3a176bc53 sys/external/bsd/drm2/linux/files.drmkms_linux
--- a/sys/external/bsd/drm2/linux/files.drmkms_linux    Sun Dec 19 01:34:46 2021 +0000
+++ b/sys/external/bsd/drm2/linux/files.drmkms_linux    Sun Dec 19 01:34:57 2021 +0000
@@ -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_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
diff -r 840c27b024ff -r 3ac3a176bc53 sys/external/bsd/drm2/linux/linux_stop_machine.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/external/bsd/drm2/linux/linux_stop_machine.c  Sun Dec 19 01:34:57 2021 +0000
@@ -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));
+}