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Commit e77deacb authored by Keith Owens's avatar Keith Owens Committed by Linus Torvalds
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[PATCH] x86_64: Avoid broadcasting NMI IPIs 



On some i386/x86_64 systems, sending an NMI IPI as a broadcast will
reset the system.  This seems to be a BIOS bug which affects machines
where one or more cpus are not under OS control.  It occurs on HT
systems with a version of the OS that is not compiled without HT
support.  It also occurs when a system is booted with max_cpus=n where
2 <= n < cpus known to the BIOS.  The fix is to always send NMI IPI as
a mask instead of as a broadcast.

Signed-off-by: default avatarKeith Owens <kaos@sgi.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 704fc59e

arch/x86_64/kernel/genapic_flat.c

+16 −9
Original line number Diff line number Diff line
@@ -78,21 +78,28 @@ static void flat_send_IPI_mask(cpumask_t cpumask, int vector) 


static void flat_send_IPI_allbutself(int vector)

{

#ifndef CONFIG_HOTPLUG_CPU

	if (((num_online_cpus()) - 1) >= 1)

		__send_IPI_shortcut(APIC_DEST_ALLBUT, vector,APIC_DEST_LOGICAL);

#ifdef	CONFIG_HOTPLUG_CPU

	int hotplug = 1;

#else

	int hotplug = 0;

#endif

	if (hotplug || vector == NMI_VECTOR) {

		cpumask_t allbutme = cpu_online_map;



		cpu_clear(smp_processor_id(), allbutme);



		if (!cpus_empty(allbutme))

			flat_send_IPI_mask(allbutme, vector);

#endif

	} else if (num_online_cpus() > 1) {

		__send_IPI_shortcut(APIC_DEST_ALLBUT, vector,APIC_DEST_LOGICAL);

	}

}



static void flat_send_IPI_all(int vector)

{

	if (vector == NMI_VECTOR)

		flat_send_IPI_mask(cpu_online_map, vector);

	else

		__send_IPI_shortcut(APIC_DEST_ALLINC, vector, APIC_DEST_LOGICAL);

}

include/asm-i386/mach-default/mach_ipi.h

+5 −2
Original line number Diff line number Diff line 
#ifndef __ASM_MACH_IPI_H

#define __ASM_MACH_IPI_H



/* Avoid include hell */

#define NMI_VECTOR 0x02



void send_IPI_mask_bitmask(cpumask_t mask, int vector);

void __send_IPI_shortcut(unsigned int shortcut, int vector);
@@ -13,7 +16,7 @@ static inline void send_IPI_mask(cpumask_t mask, int vector) 


static inline void __local_send_IPI_allbutself(int vector)

{

	if (no_broadcast) {

	if (no_broadcast || vector == NMI_VECTOR) {

		cpumask_t mask = cpu_online_map;



		cpu_clear(smp_processor_id(), mask);
@@ -24,7 +27,7 @@ static inline void __local_send_IPI_allbutself(int vector) 


static inline void __local_send_IPI_all(int vector)

{

	if (no_broadcast)

	if (no_broadcast || vector == NMI_VECTOR)

		send_IPI_mask(cpu_online_map, vector);

	else

		__send_IPI_shortcut(APIC_DEST_ALLINC, vector);