vboot: Separate vboot from chromeos

VBOOT_VERIFY_FIRMWARE should be independent of CHROMEOS. This allows use
of verified boot library without having to stick to CHROMEOS.

BUG=chrome-os-partner:55639

Change-Id: Ia2c328712caedd230ab295b8a613e3c1ed1532d9
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/15867
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/vboot/vboot_loader.c

@@ -0,0 +1,159 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/early_variables.h>
+#include <cbfs.h>
+#include <cbmem.h>
+#include <console/console.h>
+#include <rmodule.h>
+#include <rules.h>
+#include <string.h>
+#include <vboot/misc.h>
+#include <vboot/symbols.h>
+#include <vboot/vboot_common.h>
+
+/* The stage loading code is compiled and entered from multiple stages. The
+ * helper functions below attempt to provide more clarity on when certain
+ * code should be called. */
+
+static int verification_should_run(void)
+{
+	if (ENV_VERSTAGE && IS_ENABLED(CONFIG_SEPARATE_VERSTAGE))
+		return 1;
+
+	if (!IS_ENABLED(CONFIG_SEPARATE_VERSTAGE)) {
+		if (ENV_ROMSTAGE &&
+		    IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE))
+			return 1;
+		if (ENV_BOOTBLOCK &&
+		    IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
+			return 1;
+	}
+
+	return 0;
+}
+
+static int verstage_should_load(void)
+{
+	if (!IS_ENABLED(CONFIG_SEPARATE_VERSTAGE))
+		return 0;
+
+	if (ENV_ROMSTAGE && IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE))
+		return 1;
+
+	if (ENV_BOOTBLOCK && IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
+		return 1;
+
+	return 0;
+}
+
+static int vboot_executed CAR_GLOBAL;
+
+int vb2_logic_executed(void)
+{
+	/* If this stage is supposed to run the vboot logic ensure it has been
+	 * executed. */
+	if (verification_should_run() && car_get_var(vboot_executed))
+		return 1;
+
+	/* If this stage is supposed to load verstage and verstage is returning
+	 * back to the calling stage check that it has been executed. */
+	if (verstage_should_load() && IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE))
+		if (car_get_var(vboot_executed))
+			return 1;
+
+	/* Handle all other stages post vboot execution. */
+	if (!ENV_BOOTBLOCK) {
+		if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_BOOTBLOCK))
+			return 1;
+		if (IS_ENABLED(CONFIG_VBOOT_STARTS_IN_ROMSTAGE) &&
+				!ENV_ROMSTAGE)
+			return 1;
+	}
+
+	return 0;
+}
+
+static void vboot_prepare(void)
+{
+	if (verification_should_run()) {
+		verstage_main();
+		car_set_var(vboot_executed, 1);
+		vb2_save_recovery_reason_vbnv();
+	} else if (verstage_should_load()) {
+		struct cbfsf file;
+		struct prog verstage =
+			PROG_INIT(PROG_VERSTAGE,
+				CONFIG_CBFS_PREFIX "/verstage");
+
+		printk(BIOS_DEBUG, "VBOOT: Loading verstage.\n");
+
+		/* load verstage from RO */
+		if (cbfs_boot_locate(&file, prog_name(&verstage), NULL))
+			die("failed to load verstage");
+
+		cbfs_file_data(prog_rdev(&verstage), &file);
+
+		if (cbfs_prog_stage_load(&verstage))
+			die("failed to load verstage");
+
+		/* verify and select a slot */
+		prog_run(&verstage);
+
+		/* This is not actually possible to hit this condition at
+		 * runtime, but this provides a hint to the compiler for dead
+		 * code elimination below. */
+		if (!IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE))
+			return;
+
+		car_set_var(vboot_executed, 1);
+	}
+
+	/*
+	 * Fill in vboot cbmem objects before moving to ramstage so all
+	 * downstream users have access to vboot results. This path only
+	 * applies to platforms employing VBOOT_DYNAMIC_WORK_BUFFER because
+	 * cbmem comes online prior to vboot verification taking place. For
+	 * other platforms the vboot cbmem objects are initialized when
+	 * cbmem comes online.
+	 */
+	if (ENV_ROMSTAGE && IS_ENABLED(CONFIG_VBOOT_DYNAMIC_WORK_BUFFER)) {
+		vb2_store_selected_region();
+		vboot_fill_handoff();
+	}
+}
+
+static int vboot_locate(struct cbfs_props *props)
+{
+	struct region selected_region;
+
+	/* Don't honor vboot results until the vboot logic has run. */
+	if (!vb2_logic_executed())
+		return -1;
+
+	if (vb2_get_selected_region(&selected_region))
+		return -1;
+
+	props->offset = region_offset(&selected_region);
+	props->size = region_sz(&selected_region);
+
+	return 0;
+}
+
+const struct cbfs_locator vboot_locator = {
+	.name = "VBOOT",
+	.prepare = vboot_prepare,
+	.locate = vboot_locate,
+};