linux-kernel - [PATCH 3/3] x86, NMI: knob to disable using NMI IPIs to stop cpus

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

Message-Id: <1318346686-12349-4-git-send-email-dzickus@redhat.com>
Date:	Tue, 11 Oct 2011 11:24:46 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>, Andi Kleen <andi@...stfloor.org>,
	<x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Robert Richter <robert.richter@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	seiji.aguchi@....com, vgoyal@...hat.com, mjg@...hat.com,
	tony.luck@...el.com, gong.chen@...el.com, satoru.moriya@....com,
	avi@...hat.com, Don Zickus <dzickus@...hat.com>
Subject: [PATCH 3/3] x86, NMI: knob to disable using NMI IPIs to stop cpus

Some machines may exhibit problems using the NMI to stop other cpus.
This knob just allows one to revert back to the original behaviour to help
diagnose the problem.

Signed-off-by: Don Zickus <dzickus@...hat.com>
---
 Documentation/kernel-parameters.txt |    4 ++++
 arch/x86/kernel/smp.c               |    8 ++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6ca1f5c..dab6439 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1761,6 +1761,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	nomfgpt		[X86-32] Disable Multi-Function General Purpose
 			Timer usage (for AMD Geode machines).
 
+	nonmi_ipi	[X86] Disable using NMI IPIs during panic/reboot to
+			shutdown the other cpus.  Instead use the REBOOT_VECTOR
+			irq.
+
 	nopat		[X86] Disable PAT (page attribute table extension of
 			pagetables) support.
 
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index f54e07a..cc8026a 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -283,6 +283,14 @@ void smp_call_function_single_interrupt(struct pt_regs *regs)
 	irq_exit();
 }
 
+int __init nonmi_ipi_setup(char *str)
+{
+        native_smp_disable_nmi_ipi();
+        return 1;
+}
+
+__setup("nonmi_ipi", nonmi_ipi_setup);
+
 struct smp_ops smp_ops = {
 	.smp_prepare_boot_cpu	= native_smp_prepare_boot_cpu,
 	.smp_prepare_cpus	= native_smp_prepare_cpus,
-- 
1.7.6.4

--
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/