x86: Support Generic Initiator only proximity domains

In common with memoryless domains only register GI domains
if the proximity node is not online. If a domain is already
a memory containing domain, or a memoryless domain there is
nothing to do just because it also contains a Generic Initiator.

Signed-off-by: Jonathan Cameron <[e-mail]>
Acked-by: Borislav Petkov <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

arch/x86/include/asm/numa.h

···
 extern void __init init_cpu_to_node(void);
 extern void numa_add_cpu(int cpu);
 extern void numa_remove_cpu(int cpu);
+extern void init_gi_nodes(void);
 #else	/* CONFIG_NUMA */
 static inline void numa_set_node(int cpu, int node)	{ }
 static inline void numa_clear_node(int cpu)		{ }
 static inline void init_cpu_to_node(void)		{ }
 static inline void numa_add_cpu(int cpu)		{ }
 static inline void numa_remove_cpu(int cpu)		{ }
+static inline void init_gi_nodes(void)			{ }
 #endif	/* CONFIG_NUMA */
 
 #ifdef CONFIG_DEBUG_PER_CPU_MAPS

arch/x86/kernel/setup.c

···
 	prefill_possible_map();
 
 	init_cpu_to_node();
+	init_gi_nodes();
 
 	io_apic_init_mappings();
 

arch/x86/mm/numa.c

···
 }
 
 /*
+ * A node may exist which has one or more Generic Initiators but no CPUs and no
+ * memory.
+ *
+ * This function must be called after init_cpu_to_node(), to ensure that any
+ * memoryless CPU nodes have already been brought online, and before the
+ * node_data[nid] is needed for zone list setup in build_all_zonelists().
+ *
+ * When this function is called, any nodes containing either memory and/or CPUs
+ * will already be online and there is no need to do anything extra, even if
+ * they also contain one or more Generic Initiators.
+ */
+void __init init_gi_nodes(void)
+{
+	int nid;
+
+	for_each_node_state(nid, N_GENERIC_INITIATOR)
+		if (!node_online(nid))
+			init_memory_less_node(nid);
+}
+
+/*
  * Setup early cpu_to_node.
  *
  * Populate cpu_to_node[] only if x86_cpu_to_apicid[],