[PATCH 01/14] Add new macros for page-aligned data and bss sections.

Tim Abbott
2009-04-27T20:37:48Z

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@mit.edu>
Cc: Sam Ravnborg <sam@ravnborg.org>
---
include/asm-generic/vmlinux.lds.h | 8 ++++++++
include/linux/linkage.h | 9 +++++++++
2 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 89853bc..d6ae1bd 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -116,6 +116,14 @@
FTRACE_EVENTS() \
TRACE_SYSCALLS()

+#define PAGE_ALIGNED_DATA \
+ . = ALIGN(PAGE_SIZE) \
+ *(.data.page_aligned)
+
+#define PAGE_ALIGNED_BSS \
+ . = ALIGN(PAGE_SIZE) \
+ *(.bss.page_aligned)
+
#define RO_DATA(align) \
. = ALIGN((align)); \
.rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
diff --git a/include/linux/linkage.h b/include/linux/linkage.h
index fee9e59..af051fc 100644
--- a/include/linux/linkage.h
+++ b/include/linux/linkage.h
@@ -22,6 +22,15 @@
#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", @progbits
+#define __PAGE_ALIGNED_BSS .section ".bss.page_aligned", "aw", @nobits
+
+/*
* This is used by architectures to keep arguments on the stack
* untouched by the compiler by keeping them live until the end.
* The argument stack may be owned by the assembly-language
--
1.6.2.1