Announce boot-wrapper mode / exception level

When something goes wrong within the boot-wrapper, it can be very
helpful to know where we started from. Add an arch_announce() function
to log this early in the boot process. More information can be added
here in future.

This is logged ot the serial console as:

| Boot-wrapper v0.2
| Entered at EL3

Signed-off-by: Mark Rutland <>
Reviewed-by: Andre Przywara <>
7 files changed