Module Name: src
Committed By: tls
Date: Thu Feb 16 15:00:30 UTC 2017
Modified Files:
src/sys/arch/x86/x86: identcpu.c
Log Message:
On i386 (but not on amd64) we can enable SSE comparatively very late, when
probing/attaching the FPU. This is a problem for cpu_rng with the VIA
processors because, by design, cpu_rng attaches, and the entropy subsystem
starts up, very early.
If SSE is not enabled, calls to any "PadLock" instructions (ACE, RNG)
on the VIA processors will trap, per the manual:
linux.via.com.tw/support/beginDownload.action?eleid=181&fid=261
All VIA CPUs with PadLock, or which match the model/stepping test as
possibly having PadLock, have SSE. Just unconditionally enable it before
trying to turn the crypto block on.
Fixes crash at RNG attach time reported by Andrus V.; fix proposed by
jak@.
To generate a diff of this commit:
cvs rdiff -u -r1.52 -r1.53 src/sys/arch/x86/x86/identcpu.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/x86/x86/identcpu.c
diff -u src/sys/arch/x86/x86/identcpu.c:1.52 src/sys/arch/x86/x86/identcpu.c:1.53
--- src/sys/arch/x86/x86/identcpu.c:1.52 Thu Feb 2 08:57:04 2017
+++ src/sys/arch/x86/x86/identcpu.c Thu Feb 16 15:00:30 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: identcpu.c,v 1.52 2017/02/02 08:57:04 maxv Exp $ */
+/* $NetBSD: identcpu.c,v 1.53 2017/02/16 15:00:30 tls Exp $ */
/*-
* Copyright (c) 1999, 2000, 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.52 2017/02/02 08:57:04 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.53 2017/02/16 15:00:30 tls Exp $");
#include "opt_xen.h"
@@ -551,7 +551,19 @@ cpu_probe_c3(struct cpu_info *ci)
}
}
- /* Actually do the enables. */
+ /*
+ * Actually do the enables. It's a little gross,
+ * but per the PadLock programming guide, "Enabling
+ * PadLock", condition 3, we must enable SSE too or
+ * else the first use of RNG or ACE instructions
+ * will generate a trap.
+ *
+ * We must do this early because of kernel RNG
+ * initialization but it is safe without the full
+ * FPU-detect as all these CPUs have SSE.
+ */
+ lcr4(rcr4() | CR4_OSFXSR);
+
if (rng_enable) {
msr = rdmsr(MSR_VIA_RNG);
msr |= MSR_VIA_RNG_ENABLE;
