From e77deacb7b078156fcadf27b838a4ce1a65eda04 Mon Sep 17 00:00:00 2001 From: Keith Owens Date: Mon, 26 Jun 2006 13:59:56 +0200 Subject: [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 Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/genapic_flat.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) (limited to 'arch') diff --git a/arch/x86_64/kernel/genapic_flat.c b/arch/x86_64/kernel/genapic_flat.c index c66ca7b1d31..21c7066e236 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_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 - cpumask_t allbutme = cpu_online_map; + int hotplug = 0; +#endif + if (hotplug || vector == NMI_VECTOR) { + cpumask_t allbutme = cpu_online_map; - cpu_clear(smp_processor_id(), allbutme); + cpu_clear(smp_processor_id(), allbutme); - if (!cpus_empty(allbutme)) - flat_send_IPI_mask(allbutme, vector); -#endif + 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) -- cgit v1.2.3