chromeos: vboot_loader: Add support for SW_WP_ENABLED flag

Set VB_INIT_FLAG_SW_WP_ENABLED according to the status returned by an
optional platform / mainboard function vboot_get_sw_write_protect().

BUG=chrome-os-partner:26777
TEST=Manual on Rambi with all patches in sequence:
`crossystem sw_wpsw_boot` prints 0
`flashrom --wp-enable` and reboot
`crossystem sw_wpsw_boot` prints 1
BRANCH=Rambi

Original-Change-Id: Ifb852d75cc106d10120cfee0a396b0662282051a
Original-Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/190096
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
(cherry picked from commit c4668fc8a9ab31d9cf876b3d9ad3405756d4d683)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Idace325439958f6b490d2e6705d55e95305c4b2a
Reviewed-on: http://review.coreboot.org/7750
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)

1 files changed, 6 insertions, 0 deletions

diff --git a/src/vendorcode/google/chromeos/vboot_handoff.c b/src/vendorcode/google/chromeos/vboot_handoff.c
index 71ac5cdb48..1a66f56828 100644
--- a/src/vendorcode/google/chromeos/vboot_handoff.c
+++ b/src/vendorcode/google/chromeos/vboot_handoff.c
@@ -93,6 +93,12 @@ void *vboot_get_region(uintptr_t offset_addr, size_t size, void *dest)
        }
 }
 
+int __attribute((weak)) vboot_get_sw_write_protect(void)
+{
+	// Can be implemented by a platform / mainboard
+	return 0;
+}
+
 static void *vboot_get_payload(size_t *len)
 {
 	struct vboot_handoff *vboot_handoff;