From f90bc72ea2bcda0ac8d1f35918002a92dcc08f49 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Tue, 7 Mar 2017 15:08:42 -0600 Subject: [PATCH] x86/platform: Remove warning message for duplicate NMI handlers Orabug: 25920237 Remove the WARNING message associated with multiple NMI handlers as there are at least two that are legitimate. These are the KGDB and the UV handlers and both want to be called if the NMI has not been claimed by any other NMI handler. Use of the UNKNOWN NMI call chain dramatically lowers the NMI call rate when high frequency NMI tools are in use, notably the perf tools. It is required on systems that cannot sustain a high NMI call rate without adversely affecting the system operation. Signed-off-by: Mike Travis Reviewed-by: Dimitri Sivanich Cc: Don Zickus Cc: Peter Zijlstra Cc: Russ Anderson Cc: Frank Ramsay Cc: Tony Ernst Link: http://lkml.kernel.org/r/20170307210841.730959611@asylum.americas.sgi.com Signed-off-by: Thomas Gleixner (cherry picked from commit 0d443b70cc92d741cbc1dcbf1079897b3d8bc3cc) Signed-off-by: Somasundaram Krishnasamy Reviewed-by: Jack Vogel --- arch/x86/kernel/nmi.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index d7853489ebd9..f6dee3b19d41 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -161,11 +161,9 @@ int __register_nmi_handler(unsigned int type, struct nmiaction *action) spin_lock_irqsave(&desc->lock, flags); /* - * most handlers of type NMI_UNKNOWN never return because - * they just assume the NMI is theirs. Just a sanity check - * to manage expectations + * Indicate if there are multiple registrations on the + * internal NMI handler call chains (SERR and IO_CHECK). */ - WARN_ON_ONCE(type == NMI_UNKNOWN && !list_empty(&desc->head)); WARN_ON_ONCE(type == NMI_SERR && !list_empty(&desc->head)); WARN_ON_ONCE(type == NMI_IO_CHECK && !list_empty(&desc->head)); -- 2.50.1