x86/apic: Add max_apic_id member

There is really no point to have a callback which compares numbers.

Add a field which allows each APIC to store the maximum APIC ID supported
and fill it in for all APIC incarnations.

The next step will remove the callback.

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

@@ -277,6 +277,9 @@ struct apic {
 	u64	(*icr_read)(void);
 	void	(*icr_write)(u32 low, u32 high);
 
+	/* The limit of the APIC ID space. */
+	u32	max_apic_id;
+
 	/* Probe, setup and smpboot functions */
 	int	(*probe)(void);
 	int	(*acpi_madt_oem_check)(char *oem_id, char *oem_table_id);

arch/x86/kernel/apic/apic_flat_64.c

@@ -94,6 +94,7 @@ static struct apic apic_flat __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= flat_phys_pkg_id,
 
+	.max_apic_id			= 0xFE,
 	.get_apic_id			= flat_get_apic_id,
 	.set_apic_id			= set_apic_id,
 
@@ -170,6 +171,7 @@ static struct apic apic_physflat __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= flat_phys_pkg_id,
 
+	.max_apic_id			= 0xFE,
 	.get_apic_id			= flat_get_apic_id,
 	.set_apic_id			= set_apic_id,
 

arch/x86/kernel/apic/apic_noop.c

@@ -80,6 +80,7 @@ struct apic apic_noop __ro_after_init = {
 
 	.phys_pkg_id			= noop_phys_pkg_id,
 
+	.max_apic_id			= 0xFE,
 	.get_apic_id			= noop_get_apic_id,
 	.set_apic_id			= NULL,
 

arch/x86/kernel/apic/apic_numachip.c

@@ -239,6 +239,7 @@ static const struct apic apic_numachip1 __refconst = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= numachip_phys_pkg_id,
 
+	.max_apic_id			= UINT_MAX,
 	.get_apic_id			= numachip1_get_apic_id,
 	.set_apic_id			= numachip1_set_apic_id,
 
@@ -278,6 +279,7 @@ static const struct apic apic_numachip2 __refconst = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= numachip_phys_pkg_id,
 
+	.max_apic_id			= UINT_MAX,
 	.get_apic_id			= numachip2_get_apic_id,
 	.set_apic_id			= numachip2_set_apic_id,
 

arch/x86/kernel/apic/bigsmp_32.c

@@ -91,6 +91,7 @@ static struct apic apic_bigsmp __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= bigsmp_phys_pkg_id,
 
+	.max_apic_id			= 0xFE,
 	.get_apic_id			= bigsmp_get_apic_id,
 	.set_apic_id			= NULL,
 

arch/x86/kernel/apic/probe_32.c

@@ -47,6 +47,7 @@ static struct apic apic_default __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= default_phys_pkg_id,
 
+	.max_apic_id			= 0xFE,
 	.get_apic_id			= default_get_apic_id,
 	.set_apic_id			= NULL,
 

arch/x86/kernel/apic/x2apic_cluster.c

@@ -239,6 +239,7 @@ static struct apic apic_x2apic_cluster __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= x2apic_phys_pkg_id,
 
+	.max_apic_id			= UINT_MAX,
 	.get_apic_id			= x2apic_get_apic_id,
 	.set_apic_id			= x2apic_set_apic_id,
 

arch/x86/kernel/apic/x2apic_phys.c

@@ -163,6 +163,7 @@ static struct apic apic_x2apic_phys __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= x2apic_phys_pkg_id,
 
+	.max_apic_id			= UINT_MAX,
 	.get_apic_id			= x2apic_get_apic_id,
 	.set_apic_id			= x2apic_set_apic_id,
 

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -822,6 +822,7 @@ static struct apic apic_x2apic_uv_x __ro_after_init = {
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.phys_pkg_id			= uv_phys_pkg_id,
 
+	.max_apic_id			= UINT_MAX,
 	.get_apic_id			= x2apic_get_apic_id,
 	.set_apic_id			= set_apic_id,
 

arch/x86/xen/apic.c

@@ -138,6 +138,7 @@ static struct apic xen_pv_apic = {
 	.cpu_present_to_apicid		= xen_cpu_present_to_apicid,
 	.phys_pkg_id			= xen_phys_pkg_id, /* detect_ht */
 
+	.max_apic_id			= UINT_MAX,
 	.get_apic_id 			= xen_get_apic_id,
 	.set_apic_id 			= xen_set_apic_id, /* Can be NULL on 32-bit. */