[coreboot] [PATCH] fix 'AMD Fam10 code breaks with gcc 4.5.0'

Paul Menzel paulepanter at users.sourceforge.net
Thu Sep 2 11:11:05 CEST 2010


Dear Scott,


Am Donnerstag, den 02.09.2010, 10:59 +0200 schrieb Paul Menzel:
> Am Donnerstag, den 02.09.2010, 00:40 -0500 schrieb Scott:
> 
> > The subversion comment for -r 5571 states:
> > 
> >    The AMD Fam10 code breaks with coreboot 4.5.0.
> >    Potentially caused by reordering. Going back to 4.4.4
> >    which is known working on Fam10 until gcc or the Fam10 code is fixed.
> > 
> >    Signed-off-by: Stefan Reinauer <stepan at coresystems.de>
> >    Acked-by: Stefan Reinauer <stepan at coresystems.de>
> > 
> > 
> > I encountered the same problem and debugged it. The AP code that disables
> > cache as ram before the final halt has to be all inline. Function calls
> > require a valid stack, and the stack is kept in the very cache as ram that
> > the code is disabling. I found with gcc 450, the code for rdmsr, disable_cache,
> > and enable_cache and not getting inlined as intended. Function calls are
> 
> s/and/are/
> 
> > generated, and the first one after the AP clears msr 268 fails. The solution
> > is to force these functions to generate inline code by adding
> > __attribute__((always_inline)) to their declarations:
> 
> great find!!! Could you please send a patch according to the development
> guidelines. Especially do not forget to add your Signed-off-by line.

They are documented in the Wiki [1].

> Just to leave no doubt, could you please add that you tested your fix
> using GCC 4.5.0 with the used hardware.
> 
> […]


Thanks,

Paul


[1] http://www.coreboot.org/Development_Guidelines
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