CVS commit: src/sys/arch/x86/x86

[Maxime Villard]

Module Name:    src
Committed By:   maxv
Date:           Sat Dec 22 08:59:45 UTC 2018

Modified Files:
        src/sys/arch/x86/x86: spectre.c

Log Message:
If the CPU is not vulnerable to SpectreV4, say it in the sysctl by default.
Apply some minor style while here.


To generate a diff of this commit:
cvs rdiff -u -r1.19 -r1.20 src/sys/arch/x86/x86/spectre.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/spectre.c
diff -u src/sys/arch/x86/x86/spectre.c:1.19 src/sys/arch/x86/x86/spectre.c:1.20
--- src/sys/arch/x86/x86/spectre.c:1.19	Mon May 28 20:18:58 2018
+++ src/sys/arch/x86/x86/spectre.c	Sat Dec 22 08:59:44 2018
@@ -1,4 +1,4 @@
-/*	$NetBSD: spectre.c,v 1.19 2018/05/28 20:18:58 maxv Exp $	*/
+/*	$NetBSD: spectre.c,v 1.20 2018/12/22 08:59:44 maxv Exp $	*/
 
 /*
  * Copyright (c) 2018 NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: spectre.c,v 1.19 2018/05/28 20:18:58 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: spectre.c,v 1.20 2018/12/22 08:59:44 maxv Exp $");
 
 #include "opt_spectre.h"
 
@@ -483,7 +483,8 @@ mitigation_v4_change_cpu(void *arg1, voi
 	mitigation_v4_apply_cpu(enabled);
 }
 
-static int mitigation_v4_change(bool enabled)
+static int
+mitigation_v4_change(bool enabled)
 {
 	struct cpu_info *ci = NULL;
 	CPU_INFO_ITERATOR cii;
@@ -609,6 +610,10 @@ cpu_speculation_init(struct cpu_info *ci
 	 *
 	 * cpu0 is the one that detects the method and sets the global
 	 * variable.
+	 *
+	 * Disabled by default, as recommended by AMD, but can be enabled
+	 * dynamically. We only detect if the CPU is not vulnerable, to
+	 * mark it as 'mitigated' in the sysctl.
 	 */
 #if 0
 	if (ci == &cpu_info_primary) {
@@ -617,9 +622,18 @@ cpu_speculation_init(struct cpu_info *ci
 		    (v4_mitigation_method != V4_MITIGATION_NONE);
 		v4_set_name();
 	}
-	if (v4_mitigation_method != V4_MITIGATION_NONE) {
+	if (v4_mitigation_method != V4_MITIGATION_NONE &&
+	    v4_mitigation_method != V4_MITIGATION_INTEL_SSB_NO) {
 		mitigation_v4_apply_cpu(ci, true);
 	}
+#else
+	if (ci == &cpu_info_primary) {
+		v4_detect_method();
+		if (v4_mitigation_method == V4_MITIGATION_INTEL_SSB_NO) {
+			v4_mitigation_enabled = true;
+			v4_set_name();
+		}
+	}
 #endif
 }