Often enough the exception vectors are not on TEXT_BASE (for example
on i.MX SoCs in internal boot mode), so the board specific code did
not map the exception vectors to 0x0 but whatever happens to be on
TEXT_BASE. Also, the current section-only mapping requires the
exception vectors to be on a 1MB boundary.
Instead, create the possibility to create second level tables and
use this to map a copy of the exception vectors in a board
independent way.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

before if you specify id = 0 the next available id will be taken
otherwise fail if already registered now as in linux we use -1

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

this will allow each arch to handle the boards more simply and depending on
there need

the env var BOARD will refer to the current board dirent

for sandbox as we have only one board the board dirent is arch/sandbox/board

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>