Re: [LinuxBIOS] initram / xip issue

[Jordan Crouse]

On 07/10/07 04:52 +0200, Stefan Reinauer wrote:
> Ok, here's my latest patch that makes initram callbacks to stage0 work
> in v3. It's not all that pretty, but it is the least ugly thing I could
> find.
>
> Stefan
> This patch against LinuxBIOSv3 enables calls from initram (freely located XIP
> code) to stage0 (fixed location code) by forcing gcc to create an absolute call
> instruction to stage0.
>
> Signed-off-by: Stefan Reinauer
> Index: include/console.h
>
> --- include/console.h	(revision 503)
> +++ include/console.h	(working copy)
> @@ -46,7 +46,13 @@
>  };
>
> // 
> +#ifndef XIP

I really don't like the idea of singling out XIP segements.  I vote we
changed this to SHARED, and do this for all segments, regardless of where
they live.  The code impact should be minimal.
> int printk(int msg_level, const char *fmt, ...) 
>    __attribute__((format (printf, 2, 3)));
> +#else
> +int stage0printk(int msg_level, const char *fmt, ...)
> __attribute__((format (printf, 2, 3)));
>
> +int (*printk)(int msg_level, const char *fmt, ...) = stage0printk;
> +#endif

There has got to be a way that we can turn this into a general
purpose macro to make it easy for developers to mark new functions
as shared without understanding whats happening above
> Index: arch/x86/ldscript.ld
>
> --- arch/x86/ldscript.ld	(revision 503)
> +++ arch/x86/ldscript.ld	(working copy)
> @@ -33,10 +33,13 @@
>    .stage0_1 . : {
>    	_stage0_1 = .;
>    	*(.text);
> *(.text.*)
> *(.rodata)
> *(.rodata.*)
> *(.got)
> *(.got.*)

How much size does the GOT add?

Jordan