linux-kernel - [PATCH 2/2] x86/apic: check global clockevent in lapic timer setup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <43F901BD926A4E43B106BF17856F07559A257B5C@orsmsx508.amr.corp.intel.com>
Date:	Thu, 17 Dec 2009 09:59:23 -0800
From:	"Pan, Jacob jun" <jacob.jun.pan@...el.com>
To:	"H. Peter Anvin" <hpa@...ux.intel.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>
Subject: [PATCH 2/2] x86/apic: check global clockevent in lapic timer setup

>From 5b3b795b42796e326d34713d4785c161b52e04db Mon Sep 17 00:00:00 2001
From: Jacob Pan <jacob.jun.pan@...el.com>
Date: Thu, 17 Dec 2009 08:07:57 -0800
Subject: [PATCH 2/2] x86/apic: check global clockevent in lapic timer setup

Global clockevent is needed to calibrate local apic timer.
This patch makes sure we have a valid global clockevent prior
to lapic timer setup.
Non-pc x86 mid platform with per cpu platform timer may not
have a global clockevent device.

Signed-off-by: Jacob Pan <jacob.jun.pan@...el.com>
---
 arch/x86/kernel/apic/apic.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index aa57c07..7e7aee1 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -724,6 +724,13 @@ static int __init calibrate_APIC_clock(void)
  */
 void __init setup_boot_APIC_clock(void)
 {
+	/* global clockevent is needed for calibration */
+	if (!global_clock_event) {
+		apic_printk(APIC_DEBUG,
+				"no global clockevent for calibration\n");
+		return;
+	}
+
 	/*
 	 * The local apic timer can be disabled via the kernel
 	 * commandline or from the CPU detection code. Register the lapic
-- 
1.6.5.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/