[RFC PATCH v3 11/12] x86/apic: Mark the apic_interrupt_mode extern for disable_smp()

[Dou Liyang]

Calling native_smp_prepare_cpus() to prepare for SMP bootup, does
some sanity checking, enables APIC mode and disables SMP feature.

Now, APIC mode setup has been unified to apic_interrupt_mode_init()
earlier, the sanity checking is redundant and need to be cleaned up.

Mark the apic_interrupt_mode extern to refine the switch and remove
the redundant sanity check.

Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
---
 arch/x86/include/asm/apic.h |  9 +++++++++
 arch/x86/kernel/apic/apic.c | 12 +++--------
 arch/x86/kernel/smpboot.c   | 49 ++++++++-------------------------------------
 3 files changed, 20 insertions(+), 50 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 78a0c74..9f6ac51 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -53,6 +53,15 @@ extern int local_apic_timer_c2_ok;
 extern int disable_apic;
 extern unsigned int lapic_timer_frequency;
 
+extern enum apic_interrupt_mode_id apic_interrupt_mode;
+enum apic_interrupt_mode_id {
+	APIC_PIC = 0,
+	APIC_VIRTUAL_WIRE,
+	APIC_VIRTUAL_WIRE_NO_CONFIG,
+	APIC_SYMMETRIC_IO,
+	APIC_SYMMETRIC_IO_NO_ROUTING
+};
+
 #ifdef CONFIG_SMP
 extern void __inquire_remote_apic(int apicid);
 #else /* CONFIG_SMP */
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 5fe98b9..c2635bf 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1157,14 +1157,7 @@ void __init sync_Arb_IDs(void)
 			APIC_INT_LEVELTRIG | APIC_DM_INIT);
 }
 
-enum apic_interrupt_mode {
-	APIC_PIC = 0,
-	APIC_VIRTUAL_WIRE,
-	APIC_VIRTUAL_WIRE_NO_CONFIG,
-	APIC_SYMMETRIC_IO,
-	APIC_SYMMETRIC_IO_NO_ROUTING,
-	APIC_MODE_COUNT
-};
+enum apic_interrupt_mode_id apic_interrupt_mode;
 
 static int __init apic_interrupt_mode_select(int *upmode)
 {
@@ -1295,7 +1288,8 @@ void __init apic_interrupt_mode_init(void)
 {
 	int upmode = false;
 
-	switch (apic_interrupt_mode_select(&upmode)) {
+	apic_interrupt_mode = apic_interrupt_mode_select(&upmode);
+	switch (apic_interrupt_mode) {
 	case APIC_PIC:
 		pr_info("Keep in PIC mode(8259)\n");
 		return;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6e8c39b..bc8f475 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1193,7 +1193,7 @@ enum {
 /*
  * Various sanity checks.
  */
-static int __init smp_sanity_check(unsigned max_cpus)
+static void __init smp_sanity_check(void)
 {
 	preempt_disable();
 
@@ -1231,16 +1231,6 @@ static int __init smp_sanity_check(unsigned max_cpus)
 	}
 
 	/*
-	 * If we couldn't find an SMP configuration at boot time,
-	 * get out of here now!
-	 */
-	if (!smp_found_config && !acpi_lapic) {
-		preempt_enable();
-		pr_notice("SMP motherboard not detected\n");
-		return SMP_NO_CONFIG;
-	}
-
-	/*
 	 * Should not be necessary because the MP table should list the boot
 	 * CPU too, but we do it for the sake of robustness anyway.
 	 */
@@ -1250,29 +1240,6 @@ static int __init smp_sanity_check(unsigned max_cpus)
 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
 	}
 	preempt_enable();
-
-	/*
-	 * If we couldn't find a local APIC, then get out of here now!
-	 */
-	if (APIC_INTEGRATED(boot_cpu_apic_version) &&
-	    !boot_cpu_has(X86_FEATURE_APIC)) {
-		if (!disable_apic) {
-			pr_err("BIOS bug, local APIC #%d not detected!...\n",
-				boot_cpu_physical_apicid);
-			pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");
-		}
-		return SMP_NO_APIC;
-	}
-
-	/*
-	 * If SMP should be disabled, then really disable it!
-	 */
-	if (!max_cpus) {
-		pr_info("SMP mode deactivated\n");
-		return SMP_FORCE_UP;
-	}
-
-	return SMP_OK;
 }
 
 static void __init smp_cpu_index_default(void)
@@ -1320,18 +1287,18 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
 	set_sched_topology(x86_topology);
 
 	set_cpu_sibling_map(0);
+	smp_sanity_check();
 
-	switch (smp_sanity_check(max_cpus)) {
-	case SMP_NO_CONFIG:
-		disable_smp();
-		return;
-	case SMP_NO_APIC:
+	switch (apic_interrupt_mode) {
+	case APIC_PIC:
+	case APIC_VIRTUAL_WIRE_NO_CONFIG:
 		disable_smp();
 		return;
-	case SMP_FORCE_UP:
+	case APIC_SYMMETRIC_IO_NO_ROUTING:
 		disable_smp();
+		x86_init.timers.setup_percpu_clockev();
 		return;
-	case SMP_OK:
+	default:
 		break;
 	}
 
-- 
2.5.5