From e1e6b78824fba1bdd61d26c625547546d5c1f316 Mon Sep 17 00:00:00 2001
From: Ted Unangst <tedu@cvs.openbsd.org>
Date: Fri, 25 Jul 2003 17:41:20 +0000
Subject: make sure SYSENTER registers are 0 at boot time.  should fix an
 unusual DOS reported by Michal Zalewski to bugtraq.  ok mickey@ toby@

---
 sys/arch/i386/i386/machdep.c       | 8 +++++++-
 sys/arch/i386/include/specialreg.h | 5 ++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

(limited to 'sys')

diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index c185f43599f..fd6d0a6dccd 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.237 2003/07/07 03:07:19 tedu Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.238 2003/07/25 17:41:19 tedu Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -1260,6 +1260,12 @@ intel686_cpu_setup(cpu_device, model, step)
 	if ((model == 1) && (step < 3))
 		cpu_feature &= ~CPUID_SYS2;
 
+	/*
+	 * Make sure SYSENTER is disabled.
+	 */
+	if (cpu_feature & CPUID_SYS2)
+		wrmsr(MSR_SYSENTER_CS, 0);
+
 	/*
 	 * Disable the Pentium3 serial number.
 	 */
diff --git a/sys/arch/i386/include/specialreg.h b/sys/arch/i386/include/specialreg.h
index a3d004b7b3d..4876dec9eae 100644
--- a/sys/arch/i386/include/specialreg.h
+++ b/sys/arch/i386/include/specialreg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: specialreg.h,v 1.14 2003/06/06 11:11:54 andreas Exp $	*/
+/*	$OpenBSD: specialreg.h,v 1.15 2003/07/25 17:41:18 tedu Exp $	*/
 /*	$NetBSD: specialreg.h,v 1.7 1994/10/27 04:16:26 cgd Exp $	*/
 
 /*-
@@ -160,6 +160,9 @@
 #define	MSR_BBL_CR_TRIG		0x11a	/* PII+ only */
 #define	MSR_BBL_CR_BUSY		0x11b	/* PII+ only */
 #define	MSR_BBL_CR_CTR3		0x11e	/* PII+ only */
+#define MSR_SYSENTER_CS		0x174
+#define MSR_SYSENTER_ESP	0x175
+#define MSR_SYSENTER_EIP	0x176
 #define MSR_MCG_CAP		0x179
 #define MSR_MCG_STATUS		0x17a
 #define MSR_MCG_CTL		0x17b
-- 
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