arch/x86/assembly_entry: allow early post CAR stages to use common code

The skylake-based Chromebooks use a separate verstage which runs
just after bootblock and prior to romstage. The normal path for
romstage would be to reload the gdt, however in the previously
described scenario has verstage performing that work. Therefore,
provide that path under those conditions. The only difference
from the C_ENVIRONMENT_BOOTBLOCK scenario is that the stack
should not be reloaded since there's no way to know the top
of the stack.

Change-Id: Ic39ab52a856233d3042ac02a15ae4816ddfe07c7
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/14548
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-by: Leroy P Leahy <leroy.p.leahy@intel.com>
1 file changed