linux-kernel - [PATCH v2 06/10] platform/chrome: cros_ec_proto: separate cros_ec_wait_until

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220718050914.2267370-7-tzungbi@kernel.org>
Date:   Mon, 18 Jul 2022 05:09:10 +0000
From:   Tzung-Bi Shih <tzungbi@...nel.org>
To:     bleung@...omium.org, groeck@...omium.org
Cc:     chrome-platform@...ts.linux.dev, tzungbi@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 06/10] platform/chrome: cros_ec_proto: separate cros_ec_wait_until_complete()

EC returns EC_RES_IN_PROGRESS if the host command needs more time to
complete.  Whenever receives the return code, cros_ec_send_command()
sends EC_CMD_GET_COMMS_STATUS to query the command status.

Separate cros_ec_wait_until_complete() from cros_ec_send_command().
It sends EC_CMD_GET_COMMS_STATUS and waits until the previous command
was completed, or encountered error, or timed out.

Signed-off-by: Tzung-Bi Shih <tzungbi@...nel.org>
---
Changes from v1:
- Allocate buffer in cros_ec_wait_until_complete() statically.
- Use `return ret` instead of `break` to make the intent explicit.

 drivers/platform/chrome/cros_ec_proto.c | 74 ++++++++++++-------------
 1 file changed, 35 insertions(+), 39 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 0cec013be3d3..a6ad7f7956e6 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -134,56 +134,52 @@ static int cros_ec_xfer_command(struct cros_ec_device *ec_dev, struct cros_ec_co
 	return ret;
 }
 
-static int cros_ec_send_command(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
+static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t *result)
 {
-	int ret = cros_ec_xfer_command(ec_dev, msg);
+	struct {
+		struct cros_ec_command msg;
+		struct ec_response_get_comms_status status;
+	} __packed buf;
+	struct cros_ec_command *msg = &buf.msg;
+	struct ec_response_get_comms_status *status = &buf.status;
+	int ret = 0, i;
 
-	if (msg->result == EC_RES_IN_PROGRESS) {
-		int i;
-		struct cros_ec_command *status_msg;
-		struct ec_response_get_comms_status *status;
+	msg->version = 0;
+	msg->command = EC_CMD_GET_COMMS_STATUS;
+	msg->insize = sizeof(*status);
+	msg->outsize = 0;
 
-		status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
-				     GFP_KERNEL);
-		if (!status_msg)
-			return -ENOMEM;
+	/* Query the EC's status until it's no longer busy or we encounter an error. */
+	for (i = 0; i < EC_COMMAND_RETRIES; ++i) {
+		usleep_range(10000, 11000);
 
-		status_msg->version = 0;
-		status_msg->command = EC_CMD_GET_COMMS_STATUS;
-		status_msg->insize = sizeof(*status);
-		status_msg->outsize = 0;
+		ret = cros_ec_xfer_command(ec_dev, msg);
+		if (ret == -EAGAIN)
+			continue;
+		if (ret < 0)
+			return ret;
 
-		/*
-		 * Query the EC's status until it's no longer busy or
-		 * we encounter an error.
-		 */
-		for (i = 0; i < EC_COMMAND_RETRIES; i++) {
-			usleep_range(10000, 11000);
-
-			trace_cros_ec_request_start(status_msg);
-			ret = (*xfer_fxn)(ec_dev, status_msg);
-			trace_cros_ec_request_done(status_msg, ret);
-			if (ret == -EAGAIN)
-				continue;
-			if (ret < 0)
-				break;
-
-			msg->result = status_msg->result;
-			if (status_msg->result != EC_RES_SUCCESS)
-				break;
-
-			status = (struct ec_response_get_comms_status *)
-				 status_msg->data;
-			if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
-				break;
-		}
+		*result = msg->result;
+		if (msg->result != EC_RES_SUCCESS)
+			return ret;
 
-		kfree(status_msg);
+		if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
+			return ret;
 	}
 
 	return ret;
 }
 
+static int cros_ec_send_command(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
+{
+	int ret = cros_ec_xfer_command(ec_dev, msg);
+
+	if (msg->result == EC_RES_IN_PROGRESS)
+		ret = cros_ec_wait_until_complete(ec_dev, &msg->result);
+
+	return ret;
+}
+
 /**
  * cros_ec_prepare_tx() - Prepare an outgoing message in the output buffer.
  * @ec_dev: Device to register.
-- 
2.37.0.170.g444d1eabd0-goog