x86/x2apic: Use state information for disable

Use the state information to simplify the disable logic further.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.209387598@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 16 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 0ee96b9fe4e6..0c554f5d03a6 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1547,26 +1547,20 @@ void x2apic_setup(void)
 
 static __init void x2apic_disable(void)
 {
-        u64 msr;
-
-        if (!cpu_has_x2apic)
-                return;
-
-        rdmsrl(MSR_IA32_APICBASE, msr);
-        if (msr & X2APIC_ENABLE) {
-                u32 x2apic_id = read_apic_id();
+        u32 x2apic_id;
 
-                if (x2apic_id >= 255)
-                        panic("Cannot disable x2apic, id: %08x\n", x2apic_id);
+        if (x2apic_state != X2APIC_ON)
+                goto out;
 
-                __x2apic_disable();
-
-                x2apic_mode = 0;
-
-                register_lapic_address(mp_lapic_addr);
-        }
+        x2apic_id = read_apic_id();
+        if (x2apic_id >= 255)
+                panic("Cannot disable x2apic, id: %08x\n", x2apic_id);
 
+        __x2apic_disable();
+        register_lapic_address(mp_lapic_addr);
+out:
         x2apic_state = X2APIC_DISABLED;
+        x2apic_mode = 0;
 }
 
 static __init void x2apic_enable(void)