From be0d03f1c3d3612fe2b6aa451ae87a89382c9231 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Sat, 20 May 2006 15:00:21 -0700 Subject: [PATCH] i386 kdump boot cpu physical apicid fix o Kdump second kernel boot fails after a system crash if second kernel is UP and acpi=off and if crash occurred on a non-boot cpu. o Issue here is that MP tables report boot cpu lapic id as 0 but second kernel is booting on a different processor and MP table data is stale in this context. Hence apic_id_registered() check fails in setup_local_APIC() when called from APIC_init_uniprocessor(). o Problem is not seen if ACPI is enabled as in that case boot_cpu_physical_apicid is read from the LAPIC. o Problem is not seen with SMP kernels as well because in this case also boot_cpu_physical_apicid is read from LAPIC. (smp_boot_cpus()). o The problem is fixed by reading boot_cpu_physical_apicid from LAPIC if it is a UP kernel and CRASH_DUMP is enabled. Signed-off-by: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/apic.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/i386/kernel/apic.c') diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c index 013b85df18c6..3d4b2f3d116a 100644 --- a/arch/i386/kernel/apic.c +++ b/arch/i386/kernel/apic.c @@ -1341,6 +1341,14 @@ int __init APIC_init_uniprocessor (void) connect_bsp_APIC(); + /* + * Hack: In case of kdump, after a crash, kernel might be booting + * on a cpu with non-zero lapic id. But boot_cpu_physical_apicid + * might be zero if read from MP tables. Get it from LAPIC. + */ +#ifdef CONFIG_CRASH_DUMP + boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID)); +#endif phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid); setup_local_APIC(); -- cgit v1.2.2