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authorDon Zickus <dzickus@redhat.com>2011-10-13 15:14:27 -0400
committerIngo Molnar <mingo@elte.hu>2011-12-05 12:00:23 +0100
commitbda62633983f9db49ce0b1a9235b3709c1cda5f0 (patch)
treea19384bfa63d4341ee28776ed7554444495ffbb2
parent99e8b9ca90d688c3ac7d3a141b701c9694a93925 (diff)
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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 <dzickus@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> 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 <andi@firstfloor.org> Link: http://lkml.kernel.org/r/1318533267-18880-4-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--Documentation/kernel-parameters.txt4
-rw-r--r--arch/x86/kernel/smp.c13
2 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a0c5c5f4fce6..b4339e5a50da 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 e72b1754a2d7..113acda5879e 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,