x86: do_boot_cpu - check if we have ESR register
Impact: fix APIC IRQ irregularities on certain older boxes
We should touch the APIC ESR register if only we have it.
The patch fixes the problem mentioned by Max Kellermann:
http://lkml.org/lkml/2008/10/17/147
Bisected-by: Max Kellermann <mk@cm4all.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
[ mingo@elte.hu: build fix ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 7ece815..7b10933 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -893,9 +893,11 @@
smpboot_setup_warm_reset_vector(start_ip);
/*
* Be paranoid about clearing APIC errors.
- */
- apic_write(APIC_ESR, 0);
- apic_read(APIC_ESR);
+ */
+ if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
+ apic_write(APIC_ESR, 0);
+ apic_read(APIC_ESR);
+ }
}
/*