2 files changed, 21 insertions, 0 deletions

diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h
index c1f06289b14b..86af26091d6c 100644
--- a/arch/x86/include/asm/iomap.h
+++ b/arch/x86/include/asm/iomap.h
@@ -23,6 +23,9 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 
+int
+is_io_mapping_possible(resource_size_t base, unsigned long size);
+
 void *
 iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
 
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index ca53224fc56c..6c2b1af16926 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -20,6 +20,24 @@
 #include <asm/pat.h>
 #include <linux/module.h>
 
+#ifdef CONFIG_X86_PAE
+int
+is_io_mapping_possible(resource_size_t base, unsigned long size)
+{
+        return 1;
+}
+#else
+int
+is_io_mapping_possible(resource_size_t base, unsigned long size)
+{
+        /* There is no way to map greater than 1 << 32 address without PAE */
+        if (base + size > 0x100000000ULL)
+                return 0;
+
+        return 1;
+}
+#endif
+
 /* Map 'pfn' using fixed map 'type' and protections 'prot'
  */
 void *