From bda62633983f9db49ce0b1a9235b3709c1cda5f0 Mon Sep 17 00:00:00 2001 From: Don Zickus Date: Thu, 13 Oct 2011 15:14:27 -0400 Subject: [PATCH] x86, NMI: Add 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. V2: make function static Signed-off-by: Don Zickus Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Robert Richter Cc: seiji.aguchi@hds.com Cc: vgoyal@redhat.com Cc: mjg@redhat.com Cc: tony.luck@intel.com Cc: gong.chen@intel.com Cc: satoru.moriya@hds.com Cc: avi@redhat.com Cc: Andi Kleen Link: http://lkml.kernel.org/r/1318533267-18880-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 4 ++++ arch/x86/kernel/smp.c | 13 +++++++++++++ 2 files changed, 17 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a0c5c5f..b4339e5 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1796,6 +1796,10 @@ 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 e72b175..113acda 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -249,6 +249,11 @@ static void native_irq_stop_other_cpus(int wait) local_irq_restore(flags); } +static void native_smp_disable_nmi_ipi(void) +{ + smp_ops.stop_other_cpus = native_irq_stop_other_cpus; +} + /* * Reschedule call back. */ @@ -280,6 +285,14 @@ void smp_call_function_single_interrupt(struct pt_regs *regs) irq_exit(); } +static 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, -- 2.7.4