UBUNTU: SAUCE: (noup) arm64: Move unflatten_device_tree() call earlier.

BugLink: http://bugs.launchpad.net/bugs/1558765

In order to extract NUMA information from the device tree, we need to
have the tree in its unflattened form.

Split paging_init() into two pieces.  The first piece maps memory so
that unflatten_device_tree(), can allocate memory.  The second piece
containing the bootmem_init() call that will be patched in a follow-on
patch to add NUMA handling.

Move the unflatten_device_tree() call between the two new pieces.
Signed-off-by: David Daney <david.daney@cavium.com>
[ dannf: v15 submittal ]
Reference: http://www.spinics.net/lists/arm-kernel/msg489637.htmlSigned-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

arch/arm64/include/asm/mmu.h

@@ -28,7 +28,8 @@ typedef struct {
  */
 #define ASID(mm)	((mm)->context.id.counter & 0xffff)
 
-extern void paging_init(void);
+extern void paging_init_map_mem(void);
+extern void paging_init_rest(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
 extern void init_mem_pgprot(void);
 extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,

arch/arm64/kernel/setup.c

@@ -319,7 +319,13 @@ void __init setup_arch(char **cmdline_p)
 	/* Parse the ACPI tables for possible boot-time configuration */
 	acpi_boot_table_init();
 
-	paging_init();
+	paging_init_map_mem();
+
+	if (acpi_disabled)
+		unflatten_device_tree();
+
+	paging_init_rest();
+
 	relocate_initrd();
 
 	kasan_init();
@@ -328,12 +334,11 @@ void __init setup_arch(char **cmdline_p)
 
 	early_ioremap_reset();
 
-	if (acpi_disabled) {
-		unflatten_device_tree();
+	if (acpi_disabled)
 		psci_dt_init();
-	} else {
+	else
 		psci_acpi_init();
-	}
+
 	xen_early_init();
 
 	cpu_read_bootcpu_ops();

arch/arm64/mm/mmu.c

@@ -439,18 +439,23 @@ void fixup_init(void)
 }
 
 /*
- * paging_init() sets up the page tables, initialises the zone memory
- * maps and sets up the zero page.
+ * paging_init_map_mem() sets up the page tables so that memblock
+ * memory is usable.
  */
-void __init paging_init(void)
+void __init paging_init_map_mem(void)
 {
-	void *zero_page;
-
 	map_mem();
 	fixup_executable();
+}
 
+/*
+ * paging_init_rest() finishes setting up the page tables, initializes
+ * the zone memory maps and sets up the zero page.
+ */
+void __init paging_init_rest(void)
+{
 	/* allocate the zero page. */
-	zero_page = early_alloc(PAGE_SIZE);
+	void *zero_page = early_alloc(PAGE_SIZE);
 
 	bootmem_init();