Re: __setup()'s not processed in bk-current

[Andrew Morton <akpm@osdl.org>]

Ricky Beam <jfbeam@bluetronic.net> wrote:
>
> Do I smell some bad pointer math?  Yeap:
>  DEBUG: sizeof(obs_kernel_param): 24 (0x18)
> 
>  obsolete_checksetup(): line: ro
>  obsolete_checksetup(): checking: nosmp(5) @ ffffffff80593510
>  obsolete_checksetup(): checking: <NULL>(1) @ ffffffff80593528
> 
>  p++ moved the pointer sizeof(obs_kernel_param) ahead, but that's 8 bytes
>  short.

Thanks for working that out.  It's been handing around for ages.



We're now putting 24-byte structures into .init.setup via __setup.  But
x86_64's compiler is emitting a `.align 16' in there, so they end up on
32-byte boundaries and do_early_param()'s pointer arithmetic goes wrong.

Fix that up by forcing the compiler to align these structures to sizeof(long).



---

 25-akpm/include/linux/init.h |    1 +
 1 files changed, 1 insertion(+)

diff -puN include/linux/init.h~x86_64-setup-section-alignment-fix include/linux/init.h
--- 25/include/linux/init.h~x86_64-setup-section-alignment-fix	2004-06-28 16:47:41.000000000 -0700
+++ 25-akpm/include/linux/init.h	2004-06-28 16:47:41.000000000 -0700
@@ -119,6 +119,7 @@ struct obs_kernel_param {
 	static struct obs_kernel_param __setup_##unique_id	\
 		 __attribute_used__				\
 		 __attribute__((__section__(".init.setup")))	\
+		__attribute__((aligned((sizeof(long)))))	\
 		= { __setup_str_##unique_id, fn, early }
 
 #define __setup_null_param(str, unique_id)			\

_