x86, efi: Ensure that the entirity of a region is mapped

It's possible for init_memory_mapping() to fail to map the entire region
if it crosses a boundary, so ensure that we complete the mapping.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Link: http://lkml.kernel.org/r/1304623186-18261-5-git-send-email-mjg@redhat.comSigned-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/platform/efi/efi_64.c

@@ -89,8 +89,10 @@ void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 		return ioremap(phys_addr, size);
 
 	last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
-	if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size)
-		return NULL;
+	if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
+		unsigned long top = last_map_pfn << PAGE_SHIFT;
+		efi_ioremap(top, size - (top - phys_addr), type);
+	}
 
 	return (void __iomem *)__va(phys_addr);
 }