[U-Boot] [PATCH 7/8] armv7: adapt omap3 to the new cache maintenance framework
Wolfgang Denk
wd at denx.de
Tue Jan 18 10:23:22 CET 2011
Dear Aneesh V,
In message <4D3525CD.8090001 at ti.com> you wrote:
>
> >>>> +struct __attribute__ ((__packed__)) emu_hal_params {
> >>>> + u32 num_params;
> >>>> + u32 param1;
> >>>> +};
> >>>
> >>> Why exactly do we need the "__attribute__ ((__packed__))" here?
> >>
> >> Because a pointer to it has to be passed to ROM code and ROM code
> >> wouldn't expect any padding.
> >
> > But padding would only be needed if there were any alignment
> > requirements requiring it. There are none here.
>
> Yes. But, is that guaranteed? I didn't want to make it compiler
Well, there has never been a guarantee agains broken tools doing
stupid or plain wrong things.
> dependent. Isn't it safer to use '__attribute__ ((__packed__))'
'__attribute__ ((__packed__))' has (especially on ARM) certain
side-effects that are neither needed nor wanted here, I think.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
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Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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