vboot: provide a unified flow for separate verstage

The vboot verification in a stage proper is unified
replacing duplicate code in the tegra SoC code. The
original verstage.c file is renamed to reflect its
real purpose. The support for a single verstage flow
is added to the vboot2 directory proper.

BUG=chrome-os-partner:44827
BRANCH=None
TEST=Built glados.

Change-Id: I14593e1fc69a1654fa27b512eb4b612395b94ce5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11744
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

11 files changed, 380 insertions, 448 deletions

diff --git a/src/mainboard/google/foster/Makefile.inc b/src/mainboard/google/foster/Makefile.inc
index 7b2329ea60..51208c7f12 100644
--- a/src/mainboard/google/foster/Makefile.inc
+++ b/src/mainboard/google/foster/Makefile.inc
@@ -32,7 +32,6 @@ bootblock-y += bootblock.c
 bootblock-y += pmic.c
 bootblock-y += reset.c
 
-verstage-y += verstage.c
 verstage-y += chromeos.c
 verstage-y += reset.c
 
diff --git a/src/mainboard/google/foster/verstage.c b/src/mainboard/google/foster/verstage.c
deleted file mode 100644
index d5bcd44680..0000000000
--- a/src/mainboard/google/foster/verstage.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2014 Google Inc.
- * Copyright (c) 2015, NVIDIA CORPORATION.  All rights reserved.
- *
- * 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc.
- */
-
-#include <soc/addressmap.h>
-#include <soc/funitcfg.h>
-#include <soc/padconfig.h>
-#include <soc/verstage.h>
-#include <soc/nvidia/tegra/i2c.h>
-
-void verstage_mainboard_init(void)
-{
-}
diff --git a/src/soc/nvidia/tegra132/include/soc/verstage.h b/src/soc/nvidia/tegra132/include/soc/verstage.h
index df6a386e15..d54a111942 100644
--- a/src/soc/nvidia/tegra132/include/soc/verstage.h
+++ b/src/soc/nvidia/tegra132/include/soc/verstage.h
@@ -20,6 +20,6 @@
 #ifndef __SOC_NVIDIA_TEGRA132_SOC_VERSTAGE_H__
 #define __SOC_NVIDIA_TEGRA132_SOC_VERSTAGE_H__
 
-void verstage_mainboard_init(void);
+#include <vendorcode/google/chromeos/chromeos.h>
 
 #endif /* __SOC_NVIDIA_TEGRA132_SOC_VERSTAGE_H__ */
diff --git a/src/soc/nvidia/tegra132/verstage.c b/src/soc/nvidia/tegra132/verstage.c
deleted file mode 100644
index d6eba9a8ef..0000000000
--- a/src/soc/nvidia/tegra132/verstage.c
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2014 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc.
- */
-
-#include <arch/cache.h>
-#include <arch/exception.h>
-#include <arch/hlt.h>
-#include <arch/stages.h>
-#include <console/console.h>
-#include <soc/verstage.h>
-#include <program_loading.h>
-#include <timestamp.h>
-
-void __attribute__((weak)) verstage_mainboard_init(void)
-{
-	/* Default empty implementation. */
-}
-
-static void verstage(void)
-{
-	console_init();
-	timestamp_add_now(TS_START_VBOOT);
-	exception_init();
-	verstage_mainboard_init();
-
-	run_romstage();
-}
-
-void main(void)
-{
-	verstage();
-	hlt();
-}
diff --git a/src/soc/nvidia/tegra210/include/soc/verstage.h b/src/soc/nvidia/tegra210/include/soc/verstage.h
index 6c37218e9e..d6564c932a 100644
--- a/src/soc/nvidia/tegra210/include/soc/verstage.h
+++ b/src/soc/nvidia/tegra210/include/soc/verstage.h
@@ -20,6 +20,6 @@
 #ifndef __SOC_NVIDIA_TEGRA210_SOC_VERSTAGE_H__
 #define __SOC_NVIDIA_TEGRA210_SOC_VERSTAGE_H__
 
-void verstage_mainboard_init(void);
+#include <vendorcode/google/chromeos/chromeos.h>
 
 #endif /* __SOC_NVIDIA_TEGRA210_SOC_VERSTAGE_H__ */
diff --git a/src/soc/nvidia/tegra210/verstage.c b/src/soc/nvidia/tegra210/verstage.c
deleted file mode 100644
index 6a4df29018..0000000000
--- a/src/soc/nvidia/tegra210/verstage.c
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright 2014 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc.
- */
-
-#include <arch/cache.h>
-#include <arch/exception.h>
-#include <arch/hlt.h>
-#include <soc/verstage.h>
-#include <console/console.h>
-#include <program_loading.h>
-
-void __attribute__((weak)) verstage_mainboard_init(void)
-{
-	/* Default empty implementation. */
-}
-
-static void verstage(void)
-{
-	console_init();
-	exception_init();
-	verstage_mainboard_init();
-
-	run_romstage();
-}
-
-void main(void)
-{
-	verstage();
-	hlt();
-}
diff --git a/src/vendorcode/google/chromeos/vboot2/Makefile.inc b/src/vendorcode/google/chromeos/vboot2/Makefile.inc
index 21613ba52f..c2ee868a7b 100644
--- a/src/vendorcode/google/chromeos/vboot2/Makefile.inc
+++ b/src/vendorcode/google/chromeos/vboot2/Makefile.inc
@@ -31,8 +31,9 @@ romstage-y += ../vboot_common.c
 ramstage-y += ../vboot_common.c
 
 bootblock-y += common.c
-libverstage-y += verstage.c
+libverstage-y += vboot_logic.c
 verstage-y += common.c
+verstage-y += verstage.c
 ifeq (${CONFIG_VBOOT2_MOCK_SECDATA},y)
 libverstage-y += secdata_mock.c
 else
diff --git a/src/vendorcode/google/chromeos/vboot2/misc.h b/src/vendorcode/google/chromeos/vboot2/misc.h
index d4f9f48cf0..305d0daf1a 100644
--- a/src/vendorcode/google/chromeos/vboot2/misc.h
+++ b/src/vendorcode/google/chromeos/vboot2/misc.h
@@ -23,7 +23,6 @@
 #include "../vboot_common.h"
 
 void vboot_fill_handoff(void);
-void verstage_main(void);
 void *vboot_load_stage(int stage_index,
 		       struct region *fw_main,
 		       struct vboot_components *fw_info);
diff --git a/src/vendorcode/google/chromeos/vboot2/vboot_logic.c b/src/vendorcode/google/chromeos/vboot2/vboot_logic.c
new file mode 100644
index 0000000000..76355ecdab
--- /dev/null
+++ b/src/vendorcode/google/chromeos/vboot2/vboot_logic.c
@@ -0,0 +1,352 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#include <antirollback.h>
+#include <arch/exception.h>
+#include <assert.h>
+#include <console/console.h>
+#include <console/vtxprintf.h>
+#include <delay.h>
+#include <string.h>
+#include <timestamp.h>
+#include <vb2_api.h>
+
+#include "../chromeos.h"
+#include "misc.h"
+
+#define TODO_BLOCK_SIZE 1024
+
+static int is_slot_a(struct vb2_context *ctx)
+{
+	return !(ctx->flags & VB2_CONTEXT_FW_SLOT_B);
+}
+
+/* exports */
+
+void vb2ex_printf(const char *func, const char *fmt, ...)
+{
+	va_list args;
+
+	printk(BIOS_INFO, "VB2:%s() ", func);
+	va_start(args, fmt);
+	do_printk_va_list(BIOS_INFO, fmt, args);
+	va_end(args);
+
+	return;
+}
+
+int vb2ex_tpm_clear_owner(struct vb2_context *ctx)
+{
+	uint32_t rv;
+	printk(BIOS_INFO, "Clearing TPM owner\n");
+	rv = tpm_clear_and_reenable();
+	if (rv)
+		return VB2_ERROR_EX_TPM_CLEAR_OWNER;
+	return VB2_SUCCESS;
+}
+
+int vb2ex_read_resource(struct vb2_context *ctx,
+			enum vb2_resource_index index,
+			uint32_t offset,
+			void *buf,
+			uint32_t size)
+{
+	struct region_device rdev;
+	const char *name;
+
+	switch (index) {
+	case VB2_RES_GBB:
+		name = "GBB";
+		break;
+	case VB2_RES_FW_VBLOCK:
+		if (is_slot_a(ctx))
+			name = "VBLOCK_A";
+		else
+			name = "VBLOCK_B";
+		break;
+	default:
+		return VB2_ERROR_EX_READ_RESOURCE_INDEX;
+	}
+
+	if (vboot_named_region_device(name, &rdev))
+		return VB2_ERROR_EX_READ_RESOURCE_SIZE;
+
+	if (rdev_readat(&rdev, buf, offset, size) != size)
+		return VB2_ERROR_EX_READ_RESOURCE_SIZE;
+
+	return VB2_SUCCESS;
+}
+
+/* No-op stubs that can be overridden by SoCs with hardware crypto support. */
+__attribute__((weak))
+int vb2ex_hwcrypto_digest_init(enum vb2_hash_algorithm hash_alg,
+			       uint32_t data_size)
+{
+	return VB2_ERROR_EX_HWCRYPTO_UNSUPPORTED;
+}
+
+__attribute__((weak))
+int vb2ex_hwcrypto_digest_extend(const uint8_t *buf, uint32_t size)
+{
+	BUG();	/* Should never get called if init() returned an error. */
+	return VB2_ERROR_UNKNOWN;
+}
+
+__attribute__((weak))
+int vb2ex_hwcrypto_digest_finalize(uint8_t *digest, uint32_t digest_size)
+{
+	BUG();	/* Should never get called if init() returned an error. */
+	return VB2_ERROR_UNKNOWN;
+}
+
+static int hash_body(struct vb2_context *ctx, struct region_device *fw_main)
+{
+	uint64_t load_ts;
+	uint32_t expected_size;
+	uint8_t block[TODO_BLOCK_SIZE];
+	size_t block_size = sizeof(block);
+	size_t offset;
+	int rv;
+
+	/*
+	 * Since loading the firmware and calculating its hash is intertwined,
+	 * we use this little trick to measure them separately and pretend it
+	 * was first loaded and then hashed in one piece with the timestamps.
+	 * (This split won't make sense with memory-mapped media like on x86.)
+	 */
+	load_ts = timestamp_get();
+	timestamp_add(TS_START_HASH_BODY, load_ts);
+
+	expected_size = region_device_sz(fw_main);
+	offset = 0;
+
+	/* Start the body hash */
+	rv = vb2api_init_hash(ctx, VB2_HASH_TAG_FW_BODY, &expected_size);
+	if (rv)
+		return rv;
+
+	/* Extend over the body */
+	while (expected_size) {
+		uint64_t temp_ts;
+		if (block_size > expected_size)
+			block_size = expected_size;
+
+		temp_ts = timestamp_get();
+		if (rdev_readat(fw_main, block, offset, block_size) < 0)
+			return VB2_ERROR_UNKNOWN;
+		load_ts += timestamp_get() - temp_ts;
+
+		rv = vb2api_extend_hash(ctx, block, block_size);
+		if (rv)
+			return rv;
+
+		expected_size -= block_size;
+		offset += block_size;
+	}
+
+	timestamp_add(TS_DONE_LOADING, load_ts);
+	timestamp_add_now(TS_DONE_HASHING);
+
+	/* Check the result (with RSA signature verification) */
+	rv = vb2api_check_hash(ctx);
+	if (rv)
+		return rv;
+
+	timestamp_add_now(TS_END_HASH_BODY);
+
+	return VB2_SUCCESS;
+}
+
+static int locate_firmware(struct vb2_context *ctx,
+				struct region_device *fw_main)
+{
+	const char *name;
+
+	if (is_slot_a(ctx))
+		name = "FW_MAIN_A";
+	else
+		name = "FW_MAIN_B";
+
+	return vboot_named_region_device(name, fw_main);
+}
+
+/**
+ * Save non-volatile and/or secure data if needed.
+ */
+static void save_if_needed(struct vb2_context *ctx)
+{
+	if (ctx->flags & VB2_CONTEXT_NVDATA_CHANGED) {
+		printk(BIOS_INFO, "Saving nvdata\n");
+		save_vbnv(ctx->nvdata);
+		ctx->flags &= ~VB2_CONTEXT_NVDATA_CHANGED;
+	}
+	if (ctx->flags & VB2_CONTEXT_SECDATA_CHANGED) {
+		printk(BIOS_INFO, "Saving secdata\n");
+		antirollback_write_space_firmware(ctx);
+		ctx->flags &= ~VB2_CONTEXT_SECDATA_CHANGED;
+	}
+}
+
+static uint32_t extend_pcrs(struct vb2_context *ctx)
+{
+	return tpm_extend_pcr(ctx, 0, BOOT_MODE_PCR) ||
+	       tpm_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
+}
+
+static void init_vb2_working_data(void)
+{
+	struct vb2_working_data *wd;
+	size_t work_size;
+
+	work_size = vb2_working_data_size();
+	wd = vboot_get_working_data();
+	memset(wd, 0, work_size);
+	/*
+	 * vboot prefers 16-byte alignment. This takes away 16 bytes
+	 * from the VBOOT2_WORK region, but the vboot devs said that's okay.
+	 */
+	wd->buffer_offset = ALIGN_UP(sizeof(*wd), 16);
+	wd->buffer_size = work_size - wd->buffer_offset;
+}
+
+/**
+ * Verify and select the firmware in the RW image
+ *
+ * TODO: Avoid loading a stage twice (once in hash_body & again in load_stage).
+ * when per-stage verification is ready.
+ */
+void verstage_main(void)
+{
+	struct vb2_context ctx;
+	struct region_device fw_main;
+	struct vb2_working_data *wd;
+	int rv;
+	init_vb2_working_data();
+	wd = vboot_get_working_data();
+	timestamp_add_now(TS_START_VBOOT);
+
+	/* Set up context and work buffer */
+	memset(&ctx, 0, sizeof(ctx));
+	ctx.workbuf = vboot_get_work_buffer(wd);
+	ctx.workbuf_size = wd->buffer_size;
+
+	/* Read nvdata from a non-volatile storage */
+	read_vbnv(ctx.nvdata);
+
+	/* Read secdata from TPM. Initialize TPM if secdata not found. We don't
+	 * check the return value here because vb2api_fw_phase1 will catch
+	 * invalid secdata and tell us what to do (=reboot). */
+	timestamp_add_now(TS_START_TPMINIT);
+	antirollback_read_space_firmware(&ctx);
+	timestamp_add_now(TS_END_TPMINIT);
+
+	if (!IS_ENABLED(CONFIG_VIRTUAL_DEV_SWITCH) &&
+	    get_developer_mode_switch())
+		ctx.flags |= VB2_CONTEXT_FORCE_DEVELOPER_MODE;
+
+	if (get_recovery_mode_switch()) {
+		clear_recovery_mode_switch();
+		ctx.flags |= VB2_CONTEXT_FORCE_RECOVERY_MODE;
+		if (IS_ENABLED(CONFIG_VBOOT_DISABLE_DEV_ON_RECOVERY))
+			ctx.flags |= VB2_DISABLE_DEVELOPER_MODE;
+	}
+
+	if (IS_ENABLED(CONFIG_WIPEOUT_SUPPORTED) && get_wipeout_mode_switch())
+		ctx.flags |= VB2_CONTEXT_FORCE_WIPEOUT_MODE;
+
+	if (IS_ENABLED(CONFIG_LID_SWITCH) && !get_lid_switch())
+		ctx.flags |= VB2_CONTEXT_NOFAIL_BOOT;
+
+	/* Do early init (set up secdata and NVRAM, load GBB) */
+	printk(BIOS_INFO, "Phase 1\n");
+	rv = vb2api_fw_phase1(&ctx);
+
+	if (rv) {
+		/*
+		 * If vb2api_fw_phase1 fails, check for return value.
+		 * If it is set to VB2_ERROR_API_PHASE1_RECOVERY, then continue
+		 * into recovery mode.
+		 * For any other error code, save context if needed and reboot.
+		 */
+		if (rv == VB2_ERROR_API_PHASE1_RECOVERY) {
+			printk(BIOS_INFO, "Recovery requested (%x)\n", rv);
+			save_if_needed(&ctx);
+			extend_pcrs(&ctx);	/* ignore failures */
+			timestamp_add_now(TS_END_VBOOT);
+			return;
+		}
+
+		printk(BIOS_INFO, "Reboot reqested (%x)\n", rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Determine which firmware slot to boot (based on NVRAM) */
+	printk(BIOS_INFO, "Phase 2\n");
+	rv = vb2api_fw_phase2(&ctx);
+	if (rv) {
+		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Try that slot (verify its keyblock and preamble) */
+	printk(BIOS_INFO, "Phase 3\n");
+	timestamp_add_now(TS_START_VERIFY_SLOT);
+	rv = vb2api_fw_phase3(&ctx);
+	timestamp_add_now(TS_END_VERIFY_SLOT);
+	if (rv) {
+		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	printk(BIOS_INFO, "Phase 4\n");
+	rv = locate_firmware(&ctx, &fw_main);
+	if (rv)
+		die("Failed to read FMAP to locate firmware");
+
+	rv = hash_body(&ctx, &fw_main);
+	save_if_needed(&ctx);
+	if (rv) {
+		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
+		vboot_reboot();
+	}
+
+	rv = extend_pcrs(&ctx);
+	if (rv) {
+		printk(BIOS_WARNING, "Failed to extend TPM PCRs (%#x)\n", rv);
+		vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_U_ERROR, rv);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	/* Lock TPM */
+	rv = antirollback_lock_space_firmware();
+	if (rv) {
+		printk(BIOS_INFO, "Failed to lock TPM (%x)\n", rv);
+		vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_L_ERROR, 0);
+		save_if_needed(&ctx);
+		vboot_reboot();
+	}
+
+	printk(BIOS_INFO, "Slot %c is selected\n", is_slot_a(&ctx) ? 'A' : 'B');
+	vb2_set_selected_region(wd, &fw_main);
+	timestamp_add_now(TS_END_VBOOT);
+}
diff --git a/src/vendorcode/google/chromeos/vboot2/verstage.c b/src/vendorcode/google/chromeos/vboot2/verstage.c
index 7803d39fdf..955635992f 100644
--- a/src/vendorcode/google/chromeos/vboot2/verstage.c
+++ b/src/vendorcode/google/chromeos/vboot2/verstage.c
@@ -1,7 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright 2014 Google Inc.
+ * 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
@@ -9,7 +9,7 @@
  *
  * 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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
@@ -17,333 +17,30 @@
  * Foundation, Inc.
  */
 
-#include <antirollback.h>
 #include <arch/exception.h>
-#include <assert.h>
+#include <arch/hlt.h>
 #include <console/console.h>
-#include <console/vtxprintf.h>
-#include <delay.h>
-#include <string.h>
-#include <timestamp.h>
-#include <vb2_api.h>
+#include <program_loading.h>
+#include "../vboot_common.h"
 
-#include "../chromeos.h"
-#include "misc.h"
-
-#define TODO_BLOCK_SIZE 1024
-
-static int is_slot_a(struct vb2_context *ctx)
-{
-	return !(ctx->flags & VB2_CONTEXT_FW_SLOT_B);
-}
-
-/* exports */
-
-void vb2ex_printf(const char *func, const char *fmt, ...)
+void __attribute__((weak)) verstage_mainboard_init(void)
 {
-	va_list args;
-
-	printk(BIOS_INFO, "VB2:%s() ", func);
-	va_start(args, fmt);
-	do_printk_va_list(BIOS_INFO, fmt, args);
-	va_end(args);
-
-	return;
-}
-
-int vb2ex_tpm_clear_owner(struct vb2_context *ctx)
-{
-	uint32_t rv;
-	printk(BIOS_INFO, "Clearing TPM owner\n");
-	rv = tpm_clear_and_reenable();
-	if (rv)
-		return VB2_ERROR_EX_TPM_CLEAR_OWNER;
-	return VB2_SUCCESS;
+	/* Default empty implementation. */
 }
 
-int vb2ex_read_resource(struct vb2_context *ctx,
-			enum vb2_resource_index index,
-			uint32_t offset,
-			void *buf,
-			uint32_t size)
+void verstage(void)
 {
-	struct region_device rdev;
-	const char *name;
-
-	switch (index) {
-	case VB2_RES_GBB:
-		name = "GBB";
-		break;
-	case VB2_RES_FW_VBLOCK:
-		if (is_slot_a(ctx))
-			name = "VBLOCK_A";
-		else
-			name = "VBLOCK_B";
-		break;
-	default:
-		return VB2_ERROR_EX_READ_RESOURCE_INDEX;
-	}
-
-	if (vboot_named_region_device(name, &rdev))
-		return VB2_ERROR_EX_READ_RESOURCE_SIZE;
-
-	if (rdev_readat(&rdev, buf, offset, size) != size)
-		return VB2_ERROR_EX_READ_RESOURCE_SIZE;
-
-	return VB2_SUCCESS;
-}
-
-/* No-op stubs that can be overridden by SoCs with hardware crypto support. */
-__attribute__((weak))
-int vb2ex_hwcrypto_digest_init(enum vb2_hash_algorithm hash_alg,
-			       uint32_t data_size)
-{
-	return VB2_ERROR_EX_HWCRYPTO_UNSUPPORTED;
-}
-
-__attribute__((weak))
-int vb2ex_hwcrypto_digest_extend(const uint8_t *buf, uint32_t size)
-{
-	BUG();	/* Should never get called if init() returned an error. */
-	return VB2_ERROR_UNKNOWN;
-}
-
-__attribute__((weak))
-int vb2ex_hwcrypto_digest_finalize(uint8_t *digest, uint32_t digest_size)
-{
-	BUG();	/* Should never get called if init() returned an error. */
-	return VB2_ERROR_UNKNOWN;
-}
-
-static int hash_body(struct vb2_context *ctx, struct region_device *fw_main)
-{
-	uint64_t load_ts;
-	uint32_t expected_size;
-	uint8_t block[TODO_BLOCK_SIZE];
-	size_t block_size = sizeof(block);
-	size_t offset;
-	int rv;
-
-	/*
-	 * Since loading the firmware and calculating its hash is intertwined,
-	 * we use this little trick to measure them separately and pretend it
-	 * was first loaded and then hashed in one piece with the timestamps.
-	 * (This split won't make sense with memory-mapped media like on x86.)
-	 */
-	load_ts = timestamp_get();
-	timestamp_add(TS_START_HASH_BODY, load_ts);
-
-	expected_size = region_device_sz(fw_main);
-	offset = 0;
-
-	/* Start the body hash */
-	rv = vb2api_init_hash(ctx, VB2_HASH_TAG_FW_BODY, &expected_size);
-	if (rv)
-		return rv;
-
-	/* Extend over the body */
-	while (expected_size) {
-		uint64_t temp_ts;
-		if (block_size > expected_size)
-			block_size = expected_size;
-
-		temp_ts = timestamp_get();
-		if (rdev_readat(fw_main, block, offset, block_size) < 0)
-			return VB2_ERROR_UNKNOWN;
-		load_ts += timestamp_get() - temp_ts;
-
-		rv = vb2api_extend_hash(ctx, block, block_size);
-		if (rv)
-			return rv;
-
-		expected_size -= block_size;
-		offset += block_size;
-	}
-
-	timestamp_add(TS_DONE_LOADING, load_ts);
-	timestamp_add_now(TS_DONE_HASHING);
-
-	/* Check the result (with RSA signature verification) */
-	rv = vb2api_check_hash(ctx);
-	if (rv)
-		return rv;
-
-	timestamp_add_now(TS_END_HASH_BODY);
-
-	return VB2_SUCCESS;
-}
-
-static int locate_firmware(struct vb2_context *ctx,
-				struct region_device *fw_main)
-{
-	const char *name;
-
-	if (is_slot_a(ctx))
-		name = "FW_MAIN_A";
-	else
-		name = "FW_MAIN_B";
-
-	return vboot_named_region_device(name, fw_main);
-}
-
-/**
- * Save non-volatile and/or secure data if needed.
- */
-static void save_if_needed(struct vb2_context *ctx)
-{
-	if (ctx->flags & VB2_CONTEXT_NVDATA_CHANGED) {
-		printk(BIOS_INFO, "Saving nvdata\n");
-		save_vbnv(ctx->nvdata);
-		ctx->flags &= ~VB2_CONTEXT_NVDATA_CHANGED;
-	}
-	if (ctx->flags & VB2_CONTEXT_SECDATA_CHANGED) {
-		printk(BIOS_INFO, "Saving secdata\n");
-		antirollback_write_space_firmware(ctx);
-		ctx->flags &= ~VB2_CONTEXT_SECDATA_CHANGED;
-	}
-}
-
-static uint32_t extend_pcrs(struct vb2_context *ctx)
-{
-	return tpm_extend_pcr(ctx, 0, BOOT_MODE_PCR) ||
-	       tpm_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
-}
-
-static void init_vb2_working_data(void)
-{
-	struct vb2_working_data *wd;
-	size_t work_size;
-
-	work_size = vb2_working_data_size();
-	wd = vboot_get_working_data();
-	memset(wd, 0, work_size);
-	/*
-	 * vboot prefers 16-byte alignment. This takes away 16 bytes
-	 * from the VBOOT2_WORK region, but the vboot devs said that's okay.
-	 */
-	wd->buffer_offset = ALIGN_UP(sizeof(*wd), 16);
-	wd->buffer_size = work_size - wd->buffer_offset;
-}
-
-/**
- * Verify and select the firmware in the RW image
- *
- * TODO: Avoid loading a stage twice (once in hash_body & again in load_stage).
- * when per-stage verification is ready.
- */
-void verstage_main(void)
-{
-	struct vb2_context ctx;
-	struct region_device fw_main;
-	struct vb2_working_data *wd;
-	int rv;
-	init_vb2_working_data();
-	wd = vboot_get_working_data();
-	timestamp_add_now(TS_START_VBOOT);
-
-	/* Set up context and work buffer */
-	memset(&ctx, 0, sizeof(ctx));
-	ctx.workbuf = vboot_get_work_buffer(wd);
-	ctx.workbuf_size = wd->buffer_size;
-
-	/* Read nvdata from a non-volatile storage */
-	read_vbnv(ctx.nvdata);
-
-	/* Read secdata from TPM. Initialize TPM if secdata not found. We don't
-	 * check the return value here because vb2api_fw_phase1 will catch
-	 * invalid secdata and tell us what to do (=reboot). */
-	timestamp_add_now(TS_START_TPMINIT);
-	antirollback_read_space_firmware(&ctx);
-	timestamp_add_now(TS_END_TPMINIT);
-
-	if (!IS_ENABLED(CONFIG_VIRTUAL_DEV_SWITCH) &&
-	    get_developer_mode_switch())
-		ctx.flags |= VB2_CONTEXT_FORCE_DEVELOPER_MODE;
-
-	if (get_recovery_mode_switch()) {
-		clear_recovery_mode_switch();
-		ctx.flags |= VB2_CONTEXT_FORCE_RECOVERY_MODE;
-		if (IS_ENABLED(CONFIG_VBOOT_DISABLE_DEV_ON_RECOVERY))
-			ctx.flags |= VB2_DISABLE_DEVELOPER_MODE;
-	}
-
-	if (IS_ENABLED(CONFIG_WIPEOUT_SUPPORTED) && get_wipeout_mode_switch())
-		ctx.flags |= VB2_CONTEXT_FORCE_WIPEOUT_MODE;
-
-	if (IS_ENABLED(CONFIG_LID_SWITCH) && !get_lid_switch())
-		ctx.flags |= VB2_CONTEXT_NOFAIL_BOOT;
-
-	/* Do early init (set up secdata and NVRAM, load GBB) */
-	printk(BIOS_INFO, "Phase 1\n");
-	rv = vb2api_fw_phase1(&ctx);
-	if (rv) {
-		printk(BIOS_INFO, "Recovery requested (%x)\n", rv);
-		/* If we need recovery mode, leave firmware selection now */
-		save_if_needed(&ctx);
-		extend_pcrs(&ctx);	/* ignore failures */
-		timestamp_add_now(TS_END_VBOOT);
-		return;
-	}
-
-	/* Determine which firmware slot to boot (based on NVRAM) */
-	printk(BIOS_INFO, "Phase 2\n");
-	rv = vb2api_fw_phase2(&ctx);
-	if (rv) {
-		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
-		save_if_needed(&ctx);
-		vboot_reboot();
-	}
-
-	/* Try that slot (verify its keyblock and preamble) */
-	printk(BIOS_INFO, "Phase 3\n");
-	timestamp_add_now(TS_START_VERIFY_SLOT);
-	rv = vb2api_fw_phase3(&ctx);
-	timestamp_add_now(TS_END_VERIFY_SLOT);
-	if (rv) {
-		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
-		save_if_needed(&ctx);
-		vboot_reboot();
-	}
-
-	printk(BIOS_INFO, "Phase 4\n");
-	rv = locate_firmware(&ctx, &fw_main);
-	if (rv)
-		die("Failed to read FMAP to locate firmware");
-
-	rv = hash_body(&ctx, &fw_main);
-	save_if_needed(&ctx);
-	if (rv) {
-		printk(BIOS_INFO, "Reboot requested (%x)\n", rv);
-		vboot_reboot();
-	}
-
-	rv = extend_pcrs(&ctx);
-	if (rv) {
-		printk(BIOS_WARNING, "Failed to extend TPM PCRs (%#x)\n", rv);
-		vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_U_ERROR, rv);
-		save_if_needed(&ctx);
-		vboot_reboot();
-	}
+	console_init();
+	exception_init();
+	verstage_mainboard_init();
 
-	/* Lock TPM */
-	rv = antirollback_lock_space_firmware();
-	if (rv) {
-		printk(BIOS_INFO, "Failed to lock TPM (%x)\n", rv);
-		vb2api_fail(&ctx, VB2_RECOVERY_RO_TPM_L_ERROR, 0);
-		save_if_needed(&ctx);
-		vboot_reboot();
+	if (IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE)) {
+		verstage_main();
+	} else {
+		run_romstage();
+		hlt();
 	}
-
-	printk(BIOS_INFO, "Slot %c is selected\n", is_slot_a(&ctx) ? 'A' : 'B');
-	vb2_set_selected_region(wd, &fw_main);
-	timestamp_add_now(TS_END_VBOOT);
 }
 
-#if IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE)
-void main(void)
-{
-	console_init();
-	exception_init();
-	verstage_main();
-}
-#endif
+/* This is for boards that rely on main() for an entry point of a stage. */
+void main(void) __attribute__((alias ("verstage")));
diff --git a/src/vendorcode/google/chromeos/vboot_common.h b/src/vendorcode/google/chromeos/vboot_common.h
index f4d5e11537..3a9c89bff1 100644
--- a/src/vendorcode/google/chromeos/vboot_common.h
+++ b/src/vendorcode/google/chromeos/vboot_common.h
@@ -48,4 +48,10 @@ int vboot_enable_developer(void);
 
 void vboot_reboot(void);
 
+/* Main logic for verified boot. verstage() is the stage entry point
+ * while the verstage_main() is just the core logic. */
+void verstage_main(void);
+void verstage_mainboard_init(void);
+void verstage(void);
+
 #endif /* VBOOT_COMMON_H */