x86: provide consistent cbmem_top() for CONFIG_LATE_CBMEM_INIT

For x86 systems employing CONFIG_LATE_CBMEM_INIT, set_top_of_ram() is
called in ramstage to note the upper address of the 32-bit address
space. This in turn is consumed by cbmem. However, in this scenario
cbmem_top() cannot always be relied upon because get_top_of_ram()
doesn't return the same value provided to set_top_of_ram().
To fix the inconsistency in ramstage save the value passed in
to set_top_of_ram() and defer to it as the return value for
cbmem_top().

Change-Id: Ida796fb836c59b9776019e7f8b3f2cd71156f0e5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10313
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins)
2 files changed