[PATCH] powerpc: fixup lwsync at runtime

[Benjamin Herrenschmidt]

On Tue, 2008-07-01 at 16:23 +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2008-07-01 at 00:32 -0500, Kumar Gala wrote:
> > To allow for a single kernel image on e500 v1/v2/mc we need to fixup lwsync
> > at runtime.  On e500v1/v2 lwsync causes an illop so we need to patch up
> > the code.  We default to 'sync' since that is always safe and if the cpu
> > is capable we will replace 'sync' with 'lwsync'.
> > 
> > We introduce CPU_FTR_LWSYNC as a way to determine at runtime if this is
> > needed.  This flag could be moved elsewhere since we dont really use it
> > for the normal CPU_FTR purpose.
> > 
> > Finally we only store the relative offset in the fixup section to keep it
> > as small as possible rather than using a full fixup_entry.
> > 
> > Signed-off-by: Kumar Gala <galak at kernel.crashing.org>
> 
> I'd rather have some more generic "alternatives" stuff but in the
> meantime, Ack.

Hrm... minus mpe's comments...

Cheers,
Ben.