cbmem: Always maintain backing store struct in a global on non-x86

The current CBMEM code contains an optimization that maintains the
structure with information about the CBMEM backing store in a global
variable, so that we don't have to recover it from cbmem_top() again
every single time we access CBMEM. However, due to the problems with
using globals in x86 romstage, this optimization has only been enabled
in ramstage.

However, all non-x86 platforms are SRAM-based (at least for now) and
can use globals perfectly fine in earlier stages. Therefore, this patch
extends the optimization on those platforms to all stages. This also
allows us to remove the requirement that cbmem_top() needs to return
NULL before its backing store has been initialized from those boards,
since the CBMEM code can now keep track of whether it has been
initialized by itself.

Change-Id: Ia6c1db00ae01dee485d5e96e4315cb399dc63696
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/16273
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

0 files changed, 0 insertions, 0 deletions