vboot: make vboot2_verify_firmware return

this allows each board to decide what to do after firmware verification is
done. some board needs to return back to the previous stage and let the
previous stage kick off the verified stage.

this also makes it more visible what is going to happen in the verstage since
stage_exit now resides in main().

BUG=none
BRANCH=tot
TEST=booted cosmos dev board. booted blaze in normal and recovery mode.
built for all current boards.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: I3cb466cedf2a9c2b0d48fc4b0f73f76d0714c0c7
Reviewed-on: https://chromium-review.googlesource.com/232517

src/arch/arm/armv7/bootblock_simple.c

@@ -54,7 +54,7 @@ void main(void)
 	if (IS_ENABLED(CONFIG_VBOOT2_VERIFY_FIRMWARE)) {
 		timestamp_add_now(TS_START_COPYVER);
 		if (IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE))
-			vboot2_verify_firmware();	/* doesn't return */
+			entry = vboot2_verify_firmware();
 		else
 			entry = cbfs_load_stage(CBFS_DEFAULT_MEDIA,
 						CONFIG_CBFS_PREFIX "/verstage");

src/soc/nvidia/tegra124/verstage.c

@@ -19,6 +19,8 @@
 
 #include <arch/cache.h>
 #include <arch/exception.h>
+#include <arch/hlt.h>
+#include <arch/stages.h>
 #include <console/console.h>
 #include <soc/cache.h>
 #include <soc/early_configs.h>
@@ -47,12 +49,23 @@ static void soc_init(void)
 	enable_cache();
 }
 
+static void verstage(void)
+{
+	void *entry;
+
+	soc_init();
+	early_mainboard_init();
+
+	entry = vboot2_verify_firmware();
+	if (entry != (void *)-1)
+		stage_exit(entry);
+}
+
 void main(void)
 {
 	asm volatile ("bl arm_init_caches"
 		      : : : "r0", "r1", "r2", "r3", "r4", "r5", "ip");
 
-	soc_init();
-	early_mainboard_init();
-	vboot2_verify_firmware();
+	verstage();
+	hlt();
 }

src/soc/nvidia/tegra132/verstage.c

@@ -19,6 +19,8 @@
 
 #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 <timestamp.h>
@@ -29,13 +31,22 @@ void __attribute__((weak)) verstage_mainboard_init(void)
 	/* Default empty implementation. */
 }
 
-void main(void)
+static void verstage(void)
 {
+	void *entry;
+
 	console_init();
 	timestamp_add_now(TS_START_VBOOT);
 	exception_init();
-
 	verstage_mainboard_init();
 
-	vboot2_verify_firmware();
+	entry = vboot2_verify_firmware();
+	if (entry != (void *)-1)
+		stage_exit(entry);
+}
+
+void main(void)
+{
+	verstage();
+	hlt();
 }

src/vendorcode/google/chromeos/vboot2/misc.h

@@ -22,7 +22,7 @@
 
 #include "../vboot_common.h"
 
-void vboot2_verify_firmware(void);
+void *vboot2_verify_firmware(void);
 void *vboot2_load_ramstage(void);
 void verstage_main(void);
 void *vboot_load_stage(int stage_index,

src/vendorcode/google/chromeos/vboot2/verstub.c

@@ -53,7 +53,7 @@ static struct vb2_working_data *init_vb2_working_data(void)
  * 2) We're already in the verstage. Verify firmware, then load the romstage and
  * exits to it.
  */
-void vboot2_verify_firmware(void)
+void *vboot2_verify_firmware(void)
 {
 	void *entry;
 	struct vb2_working_data *wd;
@@ -67,7 +67,6 @@ void vboot2_verify_firmware(void)
 		if (entry == (void *)-1)
 			die("failed to load verstage");
 
-		timestamp_add_now(TS_END_COPYVER);
 		/* verify and select a slot */
 		stage_exit(entry);
 	} else {
@@ -76,7 +75,7 @@ void vboot2_verify_firmware(void)
 
 	/* jump to the selected slot */
 	timestamp_add_now(TS_START_COPYROM);
-	entry = NULL;
+	entry = (void *)-1;
 	if (vboot_is_slot_selected(wd)) {
 		/* RW A or B */
 		struct vboot_region fw_main;
@@ -94,8 +93,5 @@ void vboot2_verify_firmware(void)
 	}
 	timestamp_add_now(TS_END_COPYROM);
 
-	if (entry != NULL && entry != (void *)-1)
-		stage_exit(entry);
-
-	die("failed to exit from stage\n");
+	return entry;
 }