Re: [PATCH v2 2/6] Add new NOSAVE_DATA linker script macro.

[Sam Ravnborg <sam@ravnborg.org>]

On Thu, Apr 30, 2009 at 03:54:09PM -0400, Tim Abbott wrote:
> This patch is preparation for replacing most ".data.nosave" 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 |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/include/asm-generic/vmlinux.lds.h 
> b/include/asm-generic/vmlinux.lds.h
> index 3d88c87..f5ebd2b 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -124,6 +124,13 @@
>       . = ALIGN(PAGE_SIZE);                                           \
>       *(.bss.page_aligned)
>  
> +#define NOSAVE_DATA                                                  \
> +     . = ALIGN(PAGE_SIZE);                                           \
> +     __nosave_begin = .;                                             \
> +     *(.data.nosave)                                                 \
> +     . = ALIGN(PAGE_SIZE);                                           \
> +     __nosave_end = .;
> +

You need to use:
        VMLINUX_SYMBOL(__nosave_begin) = .;

Otherwise architectures such as m68k wil break as they
add a leading underscore.

See other symbols that is defined inside vmlinux.lds.h

        Sam