From bb0a8f248dae1ed158dbf6eccafeef6f15caa920 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Sun, 10 Aug 2014 16:59:39 +0000
Subject: [PATCH] On sparc64, do not keep mappings for the destroyed sf_bufs. 
 Sparc64 pmap, unlike i386, and similar to i386/xen pv, does not tolerate
 abandoned mappings for the freed pages.

Reported and tested by:	dumbbell
Diagnosed and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
---
 sys/sparc64/include/sf_buf.h     | 35 ++++++++++++++++++++++++++++++++
 sys/sparc64/include/vmparam.h    |  2 +-
 sys/sparc64/sparc64/vm_machdep.c | 16 +++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 sys/sparc64/include/sf_buf.h

diff --git a/sys/sparc64/include/sf_buf.h b/sys/sparc64/include/sf_buf.h
new file mode 100644
index 000000000000..3566f80f22b4
--- /dev/null
+++ b/sys/sparc64/include/sf_buf.h
@@ -0,0 +1,35 @@
+/*-
+ * Copyright (c) 2014 Gleb Smirnoff <glebius@FreeBSD.org>
+ * All rights reserved.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _MACHINE_SF_BUF_H_
+#define _MACHINE_SF_BUF_H_
+
+void sf_buf_map(struct sf_buf *, int);
+int sf_buf_unmap(struct sf_buf *);
+
+#endif /* !_MACHINE_SF_BUF_H_ */
diff --git a/sys/sparc64/include/vmparam.h b/sys/sparc64/include/vmparam.h
index 10976f166f78..8e7d76c62d00 100644
--- a/sys/sparc64/include/vmparam.h
+++ b/sys/sparc64/include/vmparam.h
@@ -240,6 +240,6 @@ extern vm_offset_t vm_max_kernel_address;
 #define	ZERO_REGION_SIZE	PAGE_SIZE
 
 #define	SFBUF
-#define	SFBUF_NOMD
+#define	SFBUF_MAP
 
 #endif /* !_MACHINE_VMPARAM_H_ */
diff --git a/sys/sparc64/sparc64/vm_machdep.c b/sys/sparc64/sparc64/vm_machdep.c
index 96353eb9ee27..df184fa418bb 100644
--- a/sys/sparc64/sparc64/vm_machdep.c
+++ b/sys/sparc64/sparc64/vm_machdep.c
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/sysent.h>
 #include <sys/sched.h>
+#include <sys/sf_buf.h>
 #include <sys/sysctl.h>
 #include <sys/unistd.h>
 #include <sys/vmmeter.h>
@@ -443,3 +444,18 @@ uma_small_free(void *mem, int size, u_int8_t flags)
 	vm_page_free(m);
 	atomic_subtract_int(&vm_cnt.v_wire_count, 1);
 }
+
+void
+sf_buf_map(struct sf_buf *sf, int flags)
+{
+
+	pmap_qenter(sf->kva, &sf->m, 1);
+}
+
+int
+sf_buf_unmap(struct sf_buf *sf)
+{
+
+	pmap_qremove(sf->kva, 1);
+	return (1);
+}