[PATCH v3] x86/ACPI: Ignore CPUs that are not online capable for x2apic, entries as well

[James Puthukattukaran <james.puthukattukaran@oracle.com>]

Extending commit aa06e20f1be6 ("x86/ACPI: Don't add CPUs that are not
online capable") to include acpi_parse_x2apic as well. There is a check
for invalid apicid; however, there are BIOS FW with madt version >= 5
support that do not bother setting apic id to an invalid value since they
assume the OS will check the enabled and online capable flags.

Signed-off-by: James Puthukattukaran<james.puthukattukaran@oracle.com>
Reported-by: Benjamin Fuller<ben.fuller@oracle.com>

v2 : use 'enabled' local variable. Also fix checkpatch.pl catches
v3 : updates as per Rafael's comments
---
 arch/x86/kernel/acpi/boot.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 907cc98b1938..cf2509f9de31 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -208,7 +208,15 @@ acpi_parse_x2apic(union acpi_subtable_headers *header, const unsigned long end)
 	apic_id = processor->local_apic_id;
 	enabled = processor->lapic_flags & ACPI_MADT_ENABLED;
 
-	/* Ignore invalid ID */
+	/* don't register processors that can not be onlined */
+	if (!enabled && acpi_support_online_capable &&
+	    !(processor->lapic_flags & ACPI_MADT_ONLINE_CAPABLE))
+		return 0;
+
+	/*
+	 * for systems older than madt version 5 (does not have
+	 * ACPI_MADT_ONLINE_CAPABLE defined); ignore invalid ID
+	 */
 	if (apic_id == 0xffffffff)
 		return 0;
 
-- 
2.31.1