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authorVivek Goyal <vgoyal@in.ibm.com>2006-05-20 15:00:21 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-05-21 12:59:20 -0700
commitbe0d03f1c3d3612fe2b6aa451ae87a89382c9231 (patch)
tree6449e2071969fda7441437856da6a4739d719851 /arch/i386
parent5daa3ba0c6a41a8bb4ba17ad8d5514172e103504 (diff)
[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>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/kernel/apic.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 013b85df18c..3d4b2f3d116 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();