x86/apic: Nuke empty init_apic_ldr() callbacks

apic::init_apic_ldr() is only invoked when the APIC is initialized. So
there is really no point in having:

  - Default empty callbacks all over the place

  - Two implementations of the actual LDR init function where one is
    just unreadable gunk but does exactly the same as the other.

Make the apic::init_apic_ldr() invocation conditional, remove the empty
callbacks and consolidate the two implementation into one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic/apic_common.c b/arch/x86/kernel/apic/apic_common.c
index 41528bb3a608..d55fdb33b8e5 100644
--- a/arch/x86/kernel/apic/apic_common.c
+++ b/arch/x86/kernel/apic/apic_common.c
@@ -6,6 +6,8 @@
 #include <linux/irq.h>
 #include <asm/apic.h>
 
+#include "local.h"
+
 u32 apic_default_calc_apicid(unsigned int cpu)
 {
 	return per_cpu(x86_cpu_to_apicid, cpu);
@@ -39,3 +41,17 @@ int default_apic_id_valid(u32 apicid)
 {
 	return (apicid < 255);
 }
+
+/*
+ * Set up the logical destination ID when the APIC operates in logical
+ * destination mode.
+ */
+void default_init_apic_ldr(void)
+{
+	unsigned long val;
+
+	apic_write(APIC_DFR, APIC_DFR_FLAT);
+	val = apic_read(APIC_LDR) & ~APIC_LDR_MASK;
+	val |= SET_APIC_LOGICAL_ID(1UL << smp_processor_id());
+	apic_write(APIC_LDR, val);
+}