From 4c1aaf9dc6007ffb2f8a82b93450017db9394201 Mon Sep 17 00:00:00 2001
From: maxv <maxv@NetBSD.org>
Date: Sun, 15 May 2016 07:17:53 +0000
Subject: [PATCH] Split the PRELOADED_MODULES+BOOTSTRAP_TABLES chunk into two
 separate chunks mapped independently with RWX and RW, on both amd64 and i386.

This way the BOOTSTRAP TABLES are non-executable.
---
 sys/arch/amd64/amd64/locore.S | 21 ++++++++++-----------
 sys/arch/i386/i386/locore.S   | 23 +++++++++++------------
 2 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/sys/arch/amd64/amd64/locore.S b/sys/arch/amd64/amd64/locore.S
index 5c4c6f21df9f..081e37572c48 100644
--- a/sys/arch/amd64/amd64/locore.S
+++ b/sys/arch/amd64/amd64/locore.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: locore.S,v 1.91 2016/05/15 07:01:36 maxv Exp $	*/
+/*	$NetBSD: locore.S,v 1.92 2016/05/15 07:17:53 maxv Exp $	*/
 
 /*
  * Copyright-o-rama!
@@ -654,22 +654,21 @@ no_NOX:
 	orl	$(PG_V|PG_KW),%eax
 	fillkpt_nox
 
-	/*
-	 * We actually have to be careful here. The memory layout is as
-	 * follows:
-	 *    +----------+---------------------+------------------+
-	 *    | DATA+BSS < [PRELOADED MODULES] | BOOTSTRAP TABLES >
-	 *    +----------+---------------------+------------------+
-	 * We just map everything from < to > with RWX rights.
-	 */
+	/* Map [SYMS]+[PRELOADED MODULES] RWX. */
 	movl	$RELOC(__kernel_end),%eax
 	movl	%esi,%ecx		/* start of BOOTSTRAP TABLES */
-	addl	$TABLESIZE,%ecx		/* end of BOOTSTRAP TABLES */
-	subl	%eax,%ecx		/* subtract end of kernel image */
+	subl	%eax,%ecx
 	shrl	$PGSHIFT,%ecx
 	orl	$(PG_V|PG_KW),%eax
 	fillkpt
 
+	/* Map the BOOTSTRAP TABLES RW. */
+	movl	%esi,%eax		/* start of BOOTSTRAP TABLES */
+	movl	$TABLESIZE,%ecx		/* length of BOOTSTRAP TABLES */
+	shrl	$PGSHIFT,%ecx
+	orl	$(PG_V|PG_KW),%eax
+	fillkpt_nox
+
 	/* We are on (4). Map ISA I/O mem (later atdevbase) RWX. */
 	movl	$(IOM_BEGIN|PG_V|PG_KW/*|PG_N*/),%eax
 	movl	$(IOM_SIZE>>PGSHIFT),%ecx
diff --git a/sys/arch/i386/i386/locore.S b/sys/arch/i386/i386/locore.S
index 2007af5c595c..fce1bf85a335 100644
--- a/sys/arch/i386/i386/locore.S
+++ b/sys/arch/i386/i386/locore.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: locore.S,v 1.123 2016/05/15 07:01:36 maxv Exp $	*/
+/*	$NetBSD: locore.S,v 1.124 2016/05/15 07:17:53 maxv Exp $	*/
 
 /*
  * Copyright-o-rama!
@@ -128,7 +128,7 @@
  */
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: locore.S,v 1.123 2016/05/15 07:01:36 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: locore.S,v 1.124 2016/05/15 07:17:53 maxv Exp $");
 
 #include "opt_compat_oldboot.h"
 #include "opt_copy_symtab.h"
@@ -718,22 +718,21 @@ no_NOX:
 	orl	$(PG_V|PG_KW),%eax
 	fillkpt_nox
 
-	/*
-	 * We actually have to be careful here. The memory layout is as
-	 * follows:
-	 *    +----------+---------------------+------------------+
-	 *    | DATA+BSS < [PRELOADED MODULES] | BOOTSTRAP TABLES >
-	 *    +----------+---------------------+------------------+
-	 * We just map everything from < to > with RWX rights.
-	 */
+	/* Map [SYMS]+[PRELOADED MODULES] RWX. */
 	movl	$RELOC(__kernel_end),%eax
 	movl	%esi,%ecx		/* start of BOOTSTRAP TABLES */
-	addl	RELOC(tablesize),%ecx	/* end of BOOTSTRAP TABLES */
-	subl	%eax,%ecx		/* subtract end of kernel image */
+	subl	%eax,%ecx
 	shrl	$PGSHIFT,%ecx
 	orl	$(PG_V|PG_KW),%eax
 	fillkpt
 
+	/* Map the BOOTSTRAP TABLES RW. */
+	movl	%esi,%eax		/* start of BOOTSTRAP TABLES */
+	movl	RELOC(tablesize),%ecx	/* length of BOOTSTRAP TABLES */
+	shrl	$PGSHIFT,%ecx
+	orl	$(PG_V|PG_KW),%eax
+	fillkpt_nox
+
 	/* We are on (4). Map ISA I/O mem (later atdevbase) RWX. */
 	movl	$(IOM_BEGIN|PG_V|PG_KW/*|PG_N*/),%eax
 	movl	$(IOM_SIZE>>PGSHIFT),%ecx