[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: Keith Owens <kaos@sgi.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/genapic_flat.c b/arch/x86_64/kernel/genapic_flat.c
index c66ca7b..21c7066 100644
--- a/arch/x86_64/kernel/genapic_flat.c
+++ b/arch/x86_64/kernel/genapic_flat.c
@@ -78,22 +78,29 @@
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
- cpumask_t allbutme = cpu_online_map;
-
- cpu_clear(smp_processor_id(), allbutme);
-
- if (!cpus_empty(allbutme))
- flat_send_IPI_mask(allbutme, vector);
+ 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);
+ } else if (num_online_cpus() > 1) {
+ __send_IPI_shortcut(APIC_DEST_ALLBUT, vector,APIC_DEST_LOGICAL);
+ }
}
static void flat_send_IPI_all(int vector)
{
- __send_IPI_shortcut(APIC_DEST_ALLINC, vector, APIC_DEST_LOGICAL);
+ if (vector == NMI_VECTOR)
+ flat_send_IPI_mask(cpu_online_map, vector);
+ else
+ __send_IPI_shortcut(APIC_DEST_ALLINC, vector, APIC_DEST_LOGICAL);
}
static int flat_apic_id_registered(void)