crossystem: add phase_enforcement field

Provide 'phase_enforcement' field that indicates if a
system should have its full security features enabled while
in the factory. The backend implementation currently is only
for x86 using chromeos_acpi.

On reef:
$ grep ^ /sys/devices/platform/chromeos_acpi/GPIO.*/*
/sys/devices/platform/chromeos_acpi/GPIO.2/GPIO.0:4
/sys/devices/platform/chromeos_acpi/GPIO.2/GPIO.1:1
/sys/devices/platform/chromeos_acpi/GPIO.2/GPIO.2:10
/sys/devices/platform/chromeos_acpi/GPIO.2/GPIO.3:INT3452:00

BUG=chrome-os-partner:59951
BRANCH=None
TEST=Tested on reef with accompanying coreboot patches and flipping
internal pulls to see the correct setting.

Change-Id: Id5401d795cff8874a038f2456121549713a11237
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/418899
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
2 files changed