s390/numa: establish cpu to node mapping early

Initialize the cpu topology and therefore also the cpu to node mapping
much earlier. Fixes this warning and subsequent crashes when using the
fake numa emulation mode on s390:

WARNING: CPU: 0 PID: 1 at include/linux/cpumask.h:121 select_task_rq+0xe6/0x1a8
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.6.0-rc6-00001-ge9d867a67fd0-dirty #28
task: 00000001dd270008 ti: 00000001eccb4000 task.ti: 00000001eccb4000
Krnl PSW : 0404c00180000000 0000000000176c56 (select_task_rq+0xe6/0x1a8)
           R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
Call Trace:
([<0000000000176c30>] select_task_rq+0xc0/0x1a8)
([<0000000000177d64>] try_to_wake_up+0x2e4/0x478)
([<000000000015d46c>] create_worker+0x174/0x1c0)
([<0000000000161a98>] alloc_unbound_pwq+0x360/0x438)
([<0000000000162550>] apply_wqattrs_prepare+0x200/0x2a0)
([<000000000016266a>] apply_workqueue_attrs_locked+0x7a/0xb0)
([<0000000000162af0>] apply_workqueue_attrs+0x50/0x78)
([<000000000016441c>] __alloc_workqueue_key+0x304/0x520)
([<0000000000ee3706>] default_bdi_init+0x3e/0x70)
([<0000000000100270>] do_one_initcall+0x140/0x1d8)
([<0000000000ec9da8>] kernel_init_freeable+0x220/0x2d8)
([<0000000000984a7a>] kernel_init+0x2a/0x150)
([<00000000009913fa>] kernel_thread_starter+0x6/0xc)
([<00000000009913f4>] kernel_thread_starter+0x0/0xc)

Reviewed-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/numa/mode_emu.c

@@ -21,6 +21,7 @@
 #include <linux/kernel.h>
 #include <linux/cpumask.h>
 #include <linux/memblock.h>
+#include <linux/bootmem.h>
 #include <linux/node.h>
 #include <linux/memory.h>
 #include <linux/slab.h>
@@ -307,13 +308,11 @@ fail:
 /*
  * Allocate and initialize core to node mapping
  */
-static void create_core_to_node_map(void)
+static void __ref create_core_to_node_map(void)
 {
 	int i;
 
-	emu_cores = kzalloc(sizeof(*emu_cores), GFP_KERNEL);
-	if (emu_cores == NULL)
-		panic("Could not allocate cores to node memory");
+	emu_cores = memblock_virt_alloc(sizeof(*emu_cores), 8);
 	for (i = 0; i < ARRAY_SIZE(emu_cores->to_node_id); i++)
 		emu_cores->to_node_id[i] = NODE_ID_FREE;
 }
@@ -354,7 +353,7 @@ static struct toptree *toptree_from_topology(void)
 
 	phys = toptree_new(TOPTREE_ID_PHYS, 1);
 
-	for_each_online_cpu(cpu) {
+	for_each_cpu(cpu, &cpus_with_topology) {
 		top = &cpu_topology[cpu];
 		node = toptree_get_child(phys, 0);
 		drawer = toptree_get_child(node, top->drawer_id);

arch/s390/numa/toptree.c

@@ -7,6 +7,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/bootmem.h>
 #include <linux/cpumask.h>
 #include <linux/list.h>
 #include <linux/list_sort.h>
@@ -25,10 +26,14 @@
  * RETURNS:
  * Pointer to the new tree node or NULL on error
  */
-struct toptree *toptree_alloc(int level, int id)
+struct toptree __ref *toptree_alloc(int level, int id)
 {
-	struct toptree *res = kzalloc(sizeof(struct toptree), GFP_KERNEL);
+	struct toptree *res;
 
+	if (slab_is_available())
+		res = kzalloc(sizeof(*res), GFP_KERNEL);
+	else
+		res = memblock_virt_alloc(sizeof(*res), 8);
 	if (!res)
 		return res;
 
@@ -65,7 +70,7 @@ static void toptree_remove(struct toptree *cand)
  * cleanly using toptree_remove. Possible children are freed
  * recursively. In the end @cand itself is freed.
  */
-void toptree_free(struct toptree *cand)
+void __ref toptree_free(struct toptree *cand)
 {
 	struct toptree *child, *tmp;
 
@@ -73,7 +78,10 @@ void toptree_free(struct toptree *cand)
 		toptree_remove(cand);
 	toptree_for_each_child_safe(child, tmp, cand)
 		toptree_free(child);
-	kfree(cand);
+	if (slab_is_available())
+		kfree(cand);
+	else
+		memblock_free_early((unsigned long)cand, sizeof(*cand));
 }
 
 /**