svn commit: r353701 - head/sys/conf

[Mark Johnston]

Author: markj
Date: Thu Oct 17 21:39:23 2019
New Revision: 353701
URL: https://svnweb.freebsd.org/changeset/base/353701

Log:
  Add an ldscript for amd64 kernel modules.
  
  Use it to pad the text and read-only data sections to a 4KB boundary.
  This will be used to enforce strict memory protections for some
  sections of loadable kernel modules.
  
  Reviewed by:	kib
  MFC after:	2 weeks
  Sponsored by:	Netflix
  Differential Revision:	https://reviews.freebsd.org/D21970

Added:
  head/sys/conf/ldscript.kmod.amd64   (contents, props changed)

Added: head/sys/conf/ldscript.kmod.amd64
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ head/sys/conf/ldscript.kmod.amd64	Thu Oct 17 21:39:23 2019	(r353701)
@@ -0,0 +1,48 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Mark Johnston <markj at FreeBSD.org>
+ *
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+ /*
+  * Coalesce executable and read-only sections, and pad to page alignment so
+  * that memory protections can be strictly enforced.
+  */
+
+SECTIONS
+{
+	.text		:
+	{
+		*(.text .text.*)
+		. = ALIGN(CONSTANT(COMMONPAGESIZE));
+	}
+
+	.rodata		:
+	{
+		*(.rodata .rodata.*)
+		. = ALIGN(CONSTANT(COMMONPAGESIZE));
+	}
+}