x86/acpi: Prevent LAPIC id 0xff from being accounted

Yinghai reported that the recent changes to make the cpuid - nodeid
relationship permanent causes a cpuid ordering regression on a system which
has 2apic enabled..

The reason is that the ACPI local APIC parser has no sanity check for
apicid 0xff, which is an invalid id. So a CPU id for this invalid local
APIC id is allocated and therefor breaks the cpuid ordering.

Add a sanity check to acpi_parse_lapic() which ignores the invalid id.

Fixes: 8f54969dc8d6 ("x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping")
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>,
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: douly.fnst@cn.fujitsu.com,
Cc: zhugh.fnst@cn.fujitsu.com
Cc: Tony Luck <tony.luck@intel.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Lv Zheng <lv.zheng@intel.com>,
Cc: robert.moore@intel.com
Cc: linux-acpi@vger.kernel.org
Link: https://lkml.kernel.org/r/CAE9FiQVQx6FRXT-RdR7Crz4dg5LeUWHcUSy1KacjR+JgU_vGJg@mail.gmail.com

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 32a7d70..8a5abaa 100644 (file)
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -233,6 +233,10 @@ acpi_parse_lapic(struct acpi_subtable_header * header, const unsigned long end)
 
        acpi_table_print_madt_entry(header);
 
+       /* Ignore invalid ID */
+       if (processor->id == 0xff)
+               return 0;
+
        /*
         * We need to register disabled CPU as well to permit
         * counting disabled CPUs. This allows us to size