From: Ville Syrjälä <[email protected]> Apparently trying to poke a disabled or non-existent APIC leads to a box that doesn't even boot. Let's not do that.
No real clue if this is the right fix, but at least my P3 machine boots again. Cc: [email protected] Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: [email protected] Cc: Prarit Bhargava <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Len Brown <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Juergen Gross <[email protected]> Cc: [email protected] Cc: Eric Biederman <[email protected]> Cc: [email protected] Cc: Thomas Gleixner <[email protected]> Fixes: 2a51fe083eba ("arch/x86: Handle non enumerated CPU after physical hotplug") Signed-off-by: Ville Syrjälä <[email protected]> --- arch/x86/kernel/smpboot.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 951f093a96fe..42f5eb7b4f6c 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1409,15 +1409,17 @@ __init void prefill_possible_map(void) /* No boot processor was found in mptable or ACPI MADT */ if (!num_processors) { - int apicid = boot_cpu_physical_apicid; - int cpu = hard_smp_processor_id(); + if (boot_cpu_has(X86_FEATURE_APIC)) { + int apicid = boot_cpu_physical_apicid; + int cpu = hard_smp_processor_id(); - pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu); + pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu); - /* Make sure boot cpu is enumerated */ - if (apic->cpu_present_to_apicid(0) == BAD_APICID && - apic->apic_id_valid(apicid)) - generic_processor_info(apicid, boot_cpu_apic_version); + /* Make sure boot cpu is enumerated */ + if (apic->cpu_present_to_apicid(0) == BAD_APICID && + apic->apic_id_valid(apicid)) + generic_processor_info(apicid, boot_cpu_apic_version); + } if (!num_processors) num_processors = 1; -- 2.7.4
