x86/apic: Move logical APIC ID away from apic_bsp_setup()

apic_bsp_setup() sets and returns logical APIC ID for initializing
cpu0_logical_apicid in a SMP-capable system.

The id has nothing to do with the initialization of local APIC and I/O
APIC. And apic_bsp_setup() should be called for interrupt mode setup only.

Move the id setup into a separate helper function for cleanup and mark
apic_bsp_setup() void.
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-5-git-send-email-douly.fnst@cn.fujitsu.com

arch/x86/include/asm/apic.h

@@ -146,7 +146,7 @@ static inline int apic_force_enable(unsigned long addr)
 extern int apic_force_enable(unsigned long addr);
 #endif
 
-extern int apic_bsp_setup(bool upmode);
+extern void apic_bsp_setup(bool upmode);
 extern void apic_ap_setup(void);
 
 /*

arch/x86/kernel/apic/apic.c

@@ -2379,25 +2379,17 @@ static void __init apic_bsp_up_setup(void)
  * Returns:
  * apic_id of BSP APIC
  */
-int __init apic_bsp_setup(bool upmode)
+void __init apic_bsp_setup(bool upmode)
 {
-	int id;
-
 	connect_bsp_APIC();
 	if (upmode)
 		apic_bsp_up_setup();
 	setup_local_APIC();
 
-	if (x2apic_mode)
-		id = apic_read(APIC_LDR);
-	else
-		id = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
-
 	enable_IO_APIC();
 	end_local_APIC_setup();
 	irq_remap_enable_fault_handling();
 	setup_IO_APIC();
-	return id;
 }
 
 /*

arch/x86/kernel/smpboot.c

@@ -1294,6 +1294,14 @@ static void __init smp_cpu_index_default(void)
 	}
 }
 
+static void __init smp_get_logical_apicid(void)
+{
+	if (x2apic_mode)
+		cpu0_logical_apicid = apic_read(APIC_LDR);
+	else
+		cpu0_logical_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
+}
+
 /*
  * Prepare for SMP bootup.  The MP table or ACPI has been read
  * earlier.  Just do some sanity checking here and enable APIC mode.
@@ -1354,11 +1362,13 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
 	}
 
 	default_setup_apic_routing();
-	cpu0_logical_apicid = apic_bsp_setup(false);
+	apic_bsp_setup(false);
 
 	/* Setup local timer */
 	x86_init.timers.setup_percpu_clockev();
 
+	smp_get_logical_apicid();
+
 	pr_info("CPU0: ");
 	print_cpu_info(&cpu_data(0));