1 files changed, 5 insertions, 7 deletions

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index d35078ea1446..7db54b5d5f86 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -206,23 +206,21 @@ static void __init dtb_apic_setup(void)
 static void __init x86_flattree_get_config(void)
 {
         u32 size, map_len;
-        struct boot_param_header *dt;
+        void *dt;
 
         if (!initial_dtb)
                 return;
 
-        map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK),
-                        (u64)sizeof(struct boot_param_header));
+        map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
 
-        dt = early_memremap(initial_dtb, map_len);
-        size = be32_to_cpu(dt->totalsize);
+        initial_boot_params = dt = early_memremap(initial_dtb, map_len);
+        size = of_get_flat_dt_size();
         if (map_len < size) {
                 early_iounmap(dt, map_len);
-                dt = early_memremap(initial_dtb, size);
+                initial_boot_params = dt = early_memremap(initial_dtb, size);
                 map_len = size;
         }
 
-        initial_boot_params = dt;
         unflatten_and_copy_device_tree();
         early_iounmap(dt, map_len);
 }