arm64/numa: remove the limitation that cpu0 must bind to node0

1. Remove the old binding code.
2. Read the nid of cpu0 from dts.
3. Fallback the nid of cpu0 to 0 when numa=off is set in bootargs.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/smp.c

@@ -624,6 +624,7 @@ static void __init of_parse_and_init_cpus(void)
 			}
 
 			bootcpu_valid = true;
+			early_map_cpu_to_node(0, of_node_to_nid(dn));
 
 			/*
 			 * cpu_logical_map has already been

arch/arm64/mm/numa.c

@@ -116,16 +116,24 @@ static void __init setup_node_to_cpumask_map(void)
  */
 void numa_store_cpu_info(unsigned int cpu)
 {
-	map_cpu_to_node(cpu, numa_off ? 0 : cpu_to_node_map[cpu]);
+	map_cpu_to_node(cpu, cpu_to_node_map[cpu]);
 }
 
 void __init early_map_cpu_to_node(unsigned int cpu, int nid)
 {
 	/* fallback to node 0 */
-	if (nid < 0 || nid >= MAX_NUMNODES)
+	if (nid < 0 || nid >= MAX_NUMNODES || numa_off)
 		nid = 0;
 
 	cpu_to_node_map[cpu] = nid;
+
+	/*
+	 * We should set the numa node of cpu0 as soon as possible, because it
+	 * has already been set up online before. cpu_to_node(0) will soon be
+	 * called.
+	 */
+	if (!cpu)
+		set_cpu_numa_node(cpu, nid);
 }
 
 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
@@ -393,10 +401,6 @@ static int __init numa_init(int (*init_func)(void))
 
 	setup_node_to_cpumask_map();
 
-	/* init boot processor */
-	cpu_to_node_map[0] = 0;
-	map_cpu_to_node(0, 0);
-
 	return 0;
 }