security/vboot: Add two weak methods for vboot2

In order to make VBOOT2 independent from the CHROMEOS
kconfig option a weak method for get_write_protect_state
and get_recovery_mode_switch() is required.

Introduce a kconfig option for controlling this
behaviour.

This is a temporary fix and will be removed afterwards.

Change-Id: I3b1555bd93e1605e04d5c3ea6a752eb1459e426e
Signed-off-by: Philipp Deppenwiese <zaolin@das-labor.org>
Reviewed-on: https://review.coreboot.org/22102
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/security/vboot/Kconfig

@@ -221,6 +221,15 @@ config VBOOT_FWID_VERSION
 	  This is the second part of the FWID written to various regions of a
 	  vboot firmware image to identify its version.
 
+config VBOOT_NO_BOARD_SUPPORT
+	bool "Allow the use of vboot without board support"
+	default n
+	help
+	  Enable weak functions for get_write_protect_state and
+	  get_recovery_mode_switch in order to proceed with refactoring
+	  of the vboot2 code base. Later on this code is removed and replaced
+	  by interfaces.
+
 config RO_REGION_ONLY
 	string "Additional files that should not be copied to RW"
 	default ""

src/security/vboot/bootmode.c

@@ -169,3 +169,20 @@ int vboot_developer_mode_enabled(void)
 
 	return 0;
 }
+
+#if IS_ENABLED(CONFIG_VBOOT_NO_BOARD_SUPPORT)
+/**
+ * TODO: Create flash protection interface which implements get_write_protect_state.
+ * get_recovery_mode_switch should be implemented as default function.
+ */
+int __attribute__((weak)) get_write_protect_state(void)
+{
+	return 0;
+}
+
+int __attribute__((weak)) get_recovery_mode_switch(void)
+{
+	return 0;
+}
+
+#endif