4 files changed, 17 insertions, 2 deletions

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 15aa190..4d72aab 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -294,7 +294,7 @@ void __init fixrange_init(unsigned long start, unsigned long end,
 }
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
-static int __init page_is_ram(unsigned long pagenr)
+int page_is_ram(unsigned long pagenr)
 {
 	int i;
 
diff --git a/arch/score/mm/init.c b/arch/score/mm/init.c
index 4e3dcd0..f684a59 100644
--- a/arch/score/mm/init.c
+++ b/arch/score/mm/init.c
@@ -59,7 +59,7 @@ static unsigned long setup_zero_page(void)
 }
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
-static int __init page_is_ram(unsigned long pagenr)
+int page_is_ram(unsigned long pagenr)
 {
 	if (pagenr >= min_low_pfn && pagenr < max_low_pfn)
 		return 1;
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 83aa812..11ef795 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -188,5 +188,7 @@ extern int
 walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 		void *arg, int (*func)(unsigned long, unsigned long, void *));
 
+extern int page_is_ram(unsigned long pfn);
+
 #endif /* __ASSEMBLY__ */
 #endif	/* _LINUX_IOPORT_H */
diff --git a/kernel/resource.c b/kernel/resource.c
index fb11a58..b4d637a 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -297,6 +297,19 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 
 #endif
 
+static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
+{
+	return 1;
+}
+/*
+ * This generic page_is_ram() returns true if specified address is
+ * registered as "System RAM" in iomem_resource list.
+ */
+int __attribute__((weak)) page_is_ram(unsigned long pfn)
+{
+	return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
+}
+
 /*
  * Find empty slot in the resource tree given range and alignment.
  */