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

Stefan Reinauer stefan.reinauer at coresystems.de
Mon Sep 6 12:03:27 CEST 2010

 On 9/6/10 5:32 AM, Scott Duplichan wrote:
> Resend: one more attempt to get this patch right. The previous
> submission included the patch as an attachement. The attachment
> contained Windows-style line endings. The attachment is missing
> from the mailing list archive: "A non-text attachment was scrubbed".
> http://www.coreboot.org/pipermail/coreboot/2010-September/060090.html
The patch is there, just click on the link below the message.
(Unfortunately with a wrong name)
> Root cause: After function STOP_CAR_AND_CPU disables cache as
> ram, the cache as ram stack can no longer be used. Called 
> functions must be inlined to avoid stack usage. Also, the
> compiler must keep local variables register based and not
> allocated them from the stack. With gcc 4.5.0, some functions
> declared as inline are not being inlined. This patch forces
> these functions to always be inlined by adding the qualifier
> __attribute__((always_inline)) to their declaration.

I think this explanation should go into the two files that get the
always_inline attributes so people looking at this code 3ys (or months)
from now know why it was done this way.
> Update: Still no test reports for real hardware are available.
> If we cannot get this change tested on real hardware, I suggest
> we conditionally compile in only if gcc 4.5.0 or later is used.
I think it's safe to use it as is, though I don't have a Tilapia to test
it on.

> Signed-off-by: Scott Duplichan <scott at notabs.org>

With the explanation above added to each of the two files, this is

Acked-by: Stefan Reinauer <stepan at coresystems.de>

However, I think we should additionally look at "fixing" AMD's CAR code
to not call C functions with neither CAR or RAM backing them. I reworked
all CAR code to behave like that a while ago (ie. , but the AMD code was
considerably more complex . The complexity of the code also brings along
some bugs that currently need workarounds[1]. A proper fix for this
would be nice, but it's hard to determine what's wrong with the current
code. Should you have some insights on this, please share!


[1] http://article.gmane.org/gmane.linux.bios/57707

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