vboot: Change VbExEc implementations to support RO update

This change will be used to support EC-RO software sync by allowing for
access to the readonly region of firmware. Currently only the writable
section is accessed by vboot using VB_SELECT_FIRMWARE_A and B.

BUG=chrome-os-partner:48703
BRANCH=none
TEST=built on jerry and check that the RO hash can be read and the image
can be updated.
CQ-DEPEND=CL:319185,CL:320425,CL:320598

Change-Id: Ic3942d86b65da3123798cfd11a78056f5dab6699
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/319213
Reviewed-by: Randall Spangler <rspangler@chromium.org>

3 files changed, 41 insertions, 37 deletions

diff --git a/firmware/include/vboot_api.h b/firmware/include/vboot_api.h
index 95ef21d8..4b7f1798 100644
--- a/firmware/include/vboot_api.h
+++ b/firmware/include/vboot_api.h
@@ -891,34 +891,37 @@ VbError_t VbExEcJumpToRW(int devidx);
 VbError_t VbExEcDisableJump(int devidx);
 
 /**
- * Read the SHA-256 hash of the rewriteable EC image.
+ * Read the SHA-256 hash of the selected EC image.
  */
-VbError_t VbExEcHashRW(int devidx, const uint8_t **hash, int *hash_size);
+VbError_t VbExEcHashImage(int devidx, enum VbSelectFirmware_t select,
+			  const uint8_t **hash, int *hash_size);
 
 /**
  * Get the expected contents of the EC image associated with the main firmware
  * specified by the "select" argument.
  */
-VbError_t VbExEcGetExpectedRW(int devidx, enum VbSelectFirmware_t select,
-                              const uint8_t **image, int *image_size);
+VbError_t VbExEcGetExpectedImage(int devidx, enum VbSelectFirmware_t select,
+				 const uint8_t **image, int *image_size);
 
 /**
  * Read the SHA-256 hash of the expected contents of the EC image associated
  * with the main firmware specified by the "select" argument.
  */
-VbError_t VbExEcGetExpectedRWHash(int devidx, enum VbSelectFirmware_t select,
-		       const uint8_t **hash, int *hash_size);
+VbError_t VbExEcGetExpectedImageHash(int devidx, enum VbSelectFirmware_t select,
+				     const uint8_t **hash, int *hash_size);
 
 /**
- * Update the EC rewritable image.
+ * Update the selected EC image.
  */
-VbError_t VbExEcUpdateRW(int devidx, const uint8_t *image, int image_size);
+VbError_t VbExEcUpdateImage(int devidx, enum VbSelectFirmware_t select,
+			    const uint8_t *image, int image_size);
 
 /**
- * Lock the EC code to prevent updates until the EC is rebooted.
- * Subsequent calls to VbExEcUpdateRW() this boot will fail.
+ * Lock the selected EC code to prevent updates until the EC is rebooted.
+ * Subsequent calls to VbExEcUpdateImage() with the same region this boot will
+ * fail.
  */
-VbError_t VbExEcProtectRW(int devidx);
+VbError_t VbExEcProtect(int devidx, enum VbSelectFirmware_t select);
 
 /**
  * Info the EC of the boot mode selected by the AP.
diff --git a/firmware/lib/vboot_api_kernel.c b/firmware/lib/vboot_api_kernel.c
index 2bf183b3..903055b7 100644
--- a/firmware/lib/vboot_api_kernel.c
+++ b/firmware/lib/vboot_api_kernel.c
@@ -639,16 +639,16 @@ VbError_t VbBootRecovery(VbCommonParams *cparams, LoadKernelParams *p)
 }
 
 /**
- * Wrapper around VbExEcProtectRW() which sets recovery reason on error.
+ * Wrapper around VbExEcProtect() which sets recovery reason on error.
  */
-static VbError_t EcProtectRW(int devidx)
+static VbError_t EcProtect(int devidx, enum VbSelectFirmware_t select)
 {
-	int rv = VbExEcProtectRW(devidx);
+	int rv = VbExEcProtect(devidx, select);
 
 	if (rv == VBERROR_EC_REBOOT_TO_RO_REQUIRED) {
-		VBDEBUG(("VbExEcProtectRW() needs reboot\n"));
+		VBDEBUG(("VbExEcProtect() needs reboot\n"));
 	} else if (rv != VBERROR_SUCCESS) {
-		VBDEBUG(("VbExEcProtectRW() returned %d\n", rv));
+		VBDEBUG(("VbExEcProtect() returned %d\n", rv));
 		VbSetRecoveryRequest(VBNV_RECOVERY_EC_PROTECT);
 	}
 	return rv;
@@ -658,6 +658,7 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 {
 	VbSharedDataHeader *shared =
 		(VbSharedDataHeader *)cparams->shared_data_blob;
+	enum VbSelectFirmware_t rw;
 	int in_rw = 0;
 	int rv;
 	const uint8_t *ec_hash = NULL;
@@ -671,6 +672,8 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 	int i;
 
 	VBDEBUG(("VbEcSoftwareSync(devidx=%d)\n", devidx));
+	rw = shared->firmware_index ? VB_SELECT_FIRMWARE_B :
+	     VB_SELECT_FIRMWARE_A;
 
 	/* Determine whether the EC is in RO or RW */
 	rv = VbExEcRunningRW(devidx, &in_rw);
@@ -719,7 +722,7 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 		}
 
 		/* Protect the RW flash and stay in EC-RO */
-		rv = EcProtectRW(devidx);
+		rv = EcProtect(devidx, rw);
 		if (rv != VBERROR_SUCCESS)
 			return rv;
 
@@ -736,16 +739,16 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 	}
 
 	/* Get hash of EC-RW */
-	rv = VbExEcHashRW(devidx, &ec_hash, &ec_hash_size);
+	rv = VbExEcHashImage(devidx, rw, &ec_hash, &ec_hash_size);
 	if (rv) {
 		VBDEBUG(("VbEcSoftwareSync() - "
-			 "VbExEcHashRW() returned %d\n", rv));
+			 "VbExEcHashImage() returned %d\n", rv));
 		VbSetRecoveryRequest(VBNV_RECOVERY_EC_HASH_FAILED);
 		return VBERROR_EC_REBOOT_TO_RO_REQUIRED;
 	}
 	if (ec_hash_size != SHA256_DIGEST_SIZE) {
 		VBDEBUG(("VbEcSoftwareSync() - "
-			 "VbExEcHashRW() says size %d, not %d\n",
+			 "VbExEcHashImage() says size %d, not %d\n",
 			 ec_hash_size, SHA256_DIGEST_SIZE));
 		VbSetRecoveryRequest(VBNV_RECOVERY_EC_HASH_SIZE);
 		return VBERROR_EC_REBOOT_TO_RO_REQUIRED;
@@ -761,9 +764,7 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 	 * RO_NORMAL, so we know that the BIOS must be RW-A or RW-B, and
 	 * therefore the EC must match.
 	 */
-	rv = VbExEcGetExpectedRWHash(devidx, shared->firmware_index ?
-				 VB_SELECT_FIRMWARE_B : VB_SELECT_FIRMWARE_A,
-				 &rw_hash, &rw_hash_size);
+	rv = VbExEcGetExpectedImageHash(devidx, rw, &rw_hash, &rw_hash_size);
 
 	if (rv == VBERROR_EC_GET_EXPECTED_HASH_FROM_IMAGE) {
 		/*
@@ -799,10 +800,8 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 	 */
 	if (need_update || !rw_hash) {
 		/* Get expected EC-RW image */
-		rv = VbExEcGetExpectedRW(devidx, shared->firmware_index ?
-					 VB_SELECT_FIRMWARE_B :
-					 VB_SELECT_FIRMWARE_A,
-					 &expected, &expected_size);
+		rv = VbExEcGetExpectedImage(devidx, rw, &expected,
+					    &expected_size);
 		if (rv) {
 			VBDEBUG(("VbEcSoftwareSync() - "
 				 "VbExEcGetExpectedRW() returned %d\n", rv));
@@ -891,11 +890,11 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 			VbDisplayScreen(cparams, VB_SCREEN_WAIT, 0, &vnc);
 		}
 
-		rv = VbExEcUpdateRW(devidx, expected, expected_size);
+		rv = VbExEcUpdateImage(devidx, rw, expected, expected_size);
 
 		if (rv != VBERROR_SUCCESS) {
 			VBDEBUG(("VbEcSoftwareSync() - "
-				 "VbExEcUpdateRW() returned %d\n", rv));
+				 "VbExEcUpdateImage() returned %d\n", rv));
 
 			/*
 			 * The EC may know it needs a reboot.  It may need to
@@ -919,7 +918,7 @@ VbError_t VbEcSoftwareSync(int devidx, VbCommonParams *cparams)
 	}
 
 	/* Protect EC-RW flash */
-	rv = EcProtectRW(devidx);
+	rv = EcProtect(devidx, rw);
 	if (rv != VBERROR_SUCCESS)
 		return rv;
 
diff --git a/firmware/stub/vboot_api_stub.c b/firmware/stub/vboot_api_stub.c
index 23e3dfbe..2299a033 100644
--- a/firmware/stub/vboot_api_stub.c
+++ b/firmware/stub/vboot_api_stub.c
@@ -115,7 +115,8 @@ VbError_t VbExEcDisableJump(int devidx)
 
 #define SHA256_HASH_SIZE 32
 
-VbError_t VbExEcHashRW(int devidx, const uint8_t **hash, int *hash_size)
+VbError_t VbExEcHashImage(int devidx, enum VbSelectFirmware_t select,
+			  const uint8_t **hash, int *hash_size)
 {
 	static const uint8_t fake_hash[32] = {1, 2, 3, 4};
 
@@ -124,8 +125,8 @@ VbError_t VbExEcHashRW(int devidx, const uint8_t **hash, int *hash_size)
 	return VBERROR_SUCCESS;
 }
 
-VbError_t VbExEcGetExpectedRW(int devidx, enum VbSelectFirmware_t select,
-                              const uint8_t **image, int *image_size)
+VbError_t VbExEcGetExpectedImage(int devidx, enum VbSelectFirmware_t select,
+				 const uint8_t **image, int *image_size)
 {
 	static uint8_t fake_image[64] = {5, 6, 7, 8};
 	*image = fake_image;
@@ -133,8 +134,8 @@ VbError_t VbExEcGetExpectedRW(int devidx, enum VbSelectFirmware_t select,
 	return VBERROR_SUCCESS;
 }
 
-VbError_t VbExEcGetExpectedRWHash(int devidx, enum VbSelectFirmware_t select,
-				  const uint8_t **hash, int *hash_size)
+VbError_t VbExEcGetExpectedImageHash(int devidx, enum VbSelectFirmware_t select,
+				     const uint8_t **hash, int *hash_size)
 {
 	static const uint8_t fake_hash[32] = {1, 2, 3, 4};
 
@@ -143,12 +144,13 @@ VbError_t VbExEcGetExpectedRWHash(int devidx, enum VbSelectFirmware_t select,
 	return VBERROR_SUCCESS;
 }
 
-VbError_t VbExEcUpdateRW(int devidx, const uint8_t *image, int image_size)
+VbError_t VbExEcUpdateImage(int devidx, enum VbSelectFirmware_t select,
+			    const uint8_t *image, int image_size)
 {
 	return VBERROR_SUCCESS;
 }
 
-VbError_t VbExEcProtectRW(int devidx)
+VbError_t VbExEcProtect(int devidx, enum VbSelectFirmware_t select)
 {
 	return VBERROR_SUCCESS;
 }