Add new macros for page-aligned data and bss sections.

This patch is preparation for replacing most uses of
".bss.page_aligned" and ".data.page_aligned" in the kernel with
macros, so that the section name can later be changed without having
to touch a lot of the kernel.

The long-term goal here is to be able to change the kernel's magic
section names to those that are compatible with -ffunction-sections
-fdata-sections.  This requires renaming all magic sections with names
of the form ".data.foo".

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

include/linux/linkage.h

@@ -21,6 +21,15 @@
 #define __page_aligned_data	__section(.data.page_aligned) __aligned(PAGE_SIZE)
 #define __page_aligned_bss	__section(.bss.page_aligned) __aligned(PAGE_SIZE)
 
+/*
+ * For assembly routines.
+ *
+ * Note when using these that you must specify the appropriate
+ * alignment directives yourself
+ */
+#define __PAGE_ALIGNED_DATA	.section ".data.page_aligned", "aw"
+#define __PAGE_ALIGNED_BSS	.section ".bss.page_aligned", "aw"
+
 /*
  * This is used by architectures to keep arguments on the stack
  * untouched by the compiler by keeping them live until the end.