[PATCH v2 4/6] Add new INIT_TASK_DATA() linker script macro.

[Tim Abbott]

This patch is preparation for replacing most ".data.init_task" 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 at mit.edu>
Cc: Sam Ravnborg <sam at ravnborg.org>
---
 include/asm-generic/vmlinux.lds.h |    4 ++++
 include/linux/init_task.h         |    3 +++
 2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index fa7801b..4b020e8 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -135,6 +135,10 @@
 	. = ALIGN(alignment);						\
 	*(.data.cacheline_aligned)
 
+#define INIT_TASK_DATA(alignment)					\
+	. = ALIGN(alignment);						\
+	*(.data.init_task)
+
 #define RO_DATA(align)							\
 	. = ALIGN((align));						\
 	.rodata           : AT(ADDR(.rodata) - LOAD_OFFSET) {		\
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index d87247d..e555baa 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -184,5 +184,8 @@ extern struct cred init_cred;
 	LIST_HEAD_INIT(cpu_timers[2]),					\
 }
 
+/* Attach to the init_task data structure for proper alignment */
+#define __init_task_data __attribute__((__section__(".data.init_task")))
+
 
 #endif
-- 
1.6.2.1