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SubjectRe: __setup()'s not processed in bk-current
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) \
_

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