x86/apic: Allow apic::wait_icr_idle() to be NULL

Nuke more NOOP callbacks and make the invocation conditional. Will be
replaced with a static call later.
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)

arch/x86/include/asm/apic.h

@@ -206,12 +206,6 @@ static inline u32 native_apic_msr_read(u32 reg)
 	return (u32)msr;
 }
 
-static inline void native_x2apic_wait_icr_idle(void)
-{
-	/* no need to wait for icr idle in x2apic */
-	return;
-}
-
 static inline u32 native_safe_x2apic_wait_icr_idle(void)
 {
 	/* no need to wait for icr idle in x2apic */
@@ -376,7 +370,8 @@ static inline void apic_icr_write(u32 low, u32 high)
 
 static inline void apic_wait_icr_idle(void)
 {
-	apic->wait_icr_idle();
+	if (apic->wait_icr_idle)
+		apic->wait_icr_idle();
 }
 
 static inline u32 safe_apic_wait_icr_idle(void)

arch/x86/kernel/apic/apic_noop.c

@@ -20,7 +20,6 @@ static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vec
 static void noop_send_IPI_allbutself(int vector) { }
 static void noop_send_IPI_all(int vector) { }
 static void noop_send_IPI_self(int vector) { }
-static void noop_apic_wait_icr_idle(void) { }
 static void noop_apic_icr_write(u32 low, u32 id) { }
 
 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
@@ -105,6 +104,5 @@ struct apic apic_noop __ro_after_init = {
 	.eoi_write			= noop_apic_write,
 	.icr_read			= noop_apic_icr_read,
 	.icr_write			= noop_apic_icr_write,
-	.wait_icr_idle			= noop_apic_wait_icr_idle,
 	.safe_wait_icr_idle		= noop_safe_apic_wait_icr_idle,
 };

arch/x86/kernel/apic/apic_numachip.c

@@ -223,11 +223,6 @@ static int numachip2_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 	return 1;
 }
 
-/* APIC IPIs are queued */
-static void numachip_apic_wait_icr_idle(void)
-{
-}
-
 /* APIC NMI IPIs are queued */
 static u32 numachip_safe_apic_wait_icr_idle(void)
 {
@@ -269,7 +264,6 @@ static const struct apic apic_numachip1 __refconst = {
 	.eoi_write			= native_apic_mem_write,
 	.icr_read			= native_apic_icr_read,
 	.icr_write			= native_apic_icr_write,
-	.wait_icr_idle			= numachip_apic_wait_icr_idle,
 	.safe_wait_icr_idle		= numachip_safe_apic_wait_icr_idle,
 };
 
@@ -310,7 +304,6 @@ static const struct apic apic_numachip2 __refconst = {
 	.eoi_write			= native_apic_mem_write,
 	.icr_read			= native_apic_icr_read,
 	.icr_write			= native_apic_icr_write,
-	.wait_icr_idle			= numachip_apic_wait_icr_idle,
 	.safe_wait_icr_idle		= numachip_safe_apic_wait_icr_idle,
 };
 

arch/x86/kernel/apic/x2apic_cluster.c

@@ -266,7 +266,6 @@ static struct apic apic_x2apic_cluster __ro_after_init = {
 	.eoi_write			= native_apic_msr_eoi_write,
 	.icr_read			= native_x2apic_icr_read,
 	.icr_write			= native_x2apic_icr_write,
-	.wait_icr_idle			= native_x2apic_wait_icr_idle,
 	.safe_wait_icr_idle		= native_safe_x2apic_wait_icr_idle,
 };
 

arch/x86/kernel/apic/x2apic_phys.c

@@ -180,7 +180,6 @@ static struct apic apic_x2apic_phys __ro_after_init = {
 	.eoi_write			= native_apic_msr_eoi_write,
 	.icr_read			= native_x2apic_icr_read,
 	.icr_write			= native_x2apic_icr_write,
-	.wait_icr_idle			= native_x2apic_wait_icr_idle,
 	.safe_wait_icr_idle		= native_safe_x2apic_wait_icr_idle,
 };
 

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -854,7 +854,6 @@ static struct apic apic_x2apic_uv_x __ro_after_init = {
 	.eoi_write			= native_apic_msr_eoi_write,
 	.icr_read			= native_x2apic_icr_read,
 	.icr_write			= native_x2apic_icr_write,
-	.wait_icr_idle			= native_x2apic_wait_icr_idle,
 	.safe_wait_icr_idle		= native_safe_x2apic_wait_icr_idle,
 };
 

arch/x86/xen/apic.c

@@ -120,10 +120,6 @@ static int xen_phys_pkg_id(int initial_apic_id, int index_msb)
 	return initial_apic_id >> index_msb;
 }
 
-static void xen_noop(void)
-{
-}
-
 static int xen_cpu_present_to_apicid(int cpu)
 {
 	if (cpu_present(cpu))
@@ -165,7 +161,6 @@ static struct apic xen_pv_apic = {
 
 	.icr_read 			= xen_apic_icr_read,
 	.icr_write 			= xen_apic_icr_write,
-	.wait_icr_idle 			= xen_noop,
 	.safe_wait_icr_idle 		= xen_safe_apic_wait_icr_idle,
 };