tree 6449e2071969fda7441437856da6a4739d719851
parent 5daa3ba0c6a41a8bb4ba17ad8d5514172e103504
author Vivek Goyal <vgoyal@in.ibm.com> 1148162421 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1148241560 -0700

[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 <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>