Module Name: src
Committed By: andvar
Date: Mon Jan 13 18:51:37 UTC 2025
Modified Files:
src/sys/arch/x86/x86: identcpu.c
Log Message:
Remove stepping check for APL30 Errata. Issue also affects newer Apollo Lake
CPUs. Therefore, the stepping check is unnecessary.
Include a reference to the errata and provide a description to clarify
the nature of the issue.
Should fix PR port-amd64/58982 reported by Wolfgang Stukenbrock.
To generate a diff of this commit:
cvs rdiff -u -r1.131 -r1.132 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:1.131 src/sys/arch/x86/x86/identcpu.c:1.132
--- src/sys/arch/x86/x86/identcpu.c:1.131 Mon Dec 2 13:31:32 2024
+++ src/sys/arch/x86/x86/identcpu.c Mon Jan 13 18:51:37 2025
@@ -1,4 +1,4 @@
-/* $NetBSD: identcpu.c,v 1.131 2024/12/02 13:31:32 bouyer Exp $ */
+/* $NetBSD: identcpu.c,v 1.132 2025/01/13 18:51:37 andvar 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 1.131 2024/12/02 13:31:32 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.132 2025/01/13 18:51:37 andvar Exp $");
#include "opt_xen.h"
@@ -144,13 +144,25 @@ cpu_probe_intel_cache(struct cpu_info *c
static void
cpu_probe_intel_errata(struct cpu_info *ci)
{
- u_int family, model, stepping;
+ u_int family, model;
family = CPUID_TO_FAMILY(ci->ci_signature);
model = CPUID_TO_MODEL(ci->ci_signature);
- stepping = CPUID_TO_STEPPING(ci->ci_signature);
- if (family == 0x6 && model == 0x5C && stepping == 0x9) { /* Apollo Lake */
+ /*
+ * For details, refer to the Intel Pentium and Celeron Processor
+ * N- and J- Series Specification Update (Document number: 334820-010),
+ * August 2022, Revision 010. See page 28, Section 5.30: "APL30 A Store
+ * Instruction May Not Wake Up MWAIT."
+ * https://cdrdv2-public.intel.com/334820/334820-APL_Spec_Update_rev010.pdf
+ *
+ * Disable MWAIT/MONITOR on Apollo Lake CPUs to address the APL30 erratum.
+ * When using the MONITOR/MWAIT instruction pair, stores to the armed
+ * address range may fail to trigger MWAIT to resume execution.
+ * When these instructions are used to hatch secondary CPUs,
+ * this erratum causes SMP boot failures.
+ */
+ if (family == 0x6 && model == 0x5C) {
wrmsr(MSR_MISC_ENABLE,
rdmsr(MSR_MISC_ENABLE) & ~IA32_MISC_MWAIT_EN);
