1 files changed, 4 insertions, 0 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index c246d259822d..03c75ffd5c2a 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -422,6 +422,10 @@ void __init early_ioremap_init(void)
          * The boot-ioremap range spans multiple pmds, for which
          * we are not prepared:
          */
+#define __FIXADDR_TOP (-PAGE_SIZE)
+        BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+                     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+#undef __FIXADDR_TOP
         if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
                 WARN_ON(1);
                 printk(KERN_WARNING "pmd %p != %p\n",