tpm/tpm_ftpm_tee: support TPM_CHIP_FLAG_SYNC

This driver does not support interrupts, and receiving the response is
synchronous with sending the command.

Enable synchronous send() with TPM_CHIP_FLAG_SYNC, which implies that
->send() already fills the provided buffer with a response, and ->recv()
is not implemented.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c
index dbad83bf798edcba1e8191523abda8cad147aa73..4e63c30aeaf147e0e2d397507858dfee39152b53 100644 (file)
--- a/drivers/char/tpm/tpm_ftpm_tee.c
+++ b/drivers/char/tpm/tpm_ftpm_tee.c
@@ -31,47 +31,19 @@ static const uuid_t ftpm_ta_uuid =
                  0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96);
 
 /**
- * ftpm_tee_tpm_op_recv() - retrieve fTPM response.
- * @chip:      the tpm_chip description as specified in driver/char/tpm/tpm.h.
- * @buf:       the buffer to store data.
- * @count:     the number of bytes to read.
- *
- * Return:
- *     In case of success the number of bytes received.
- *     On failure, -errno.
- */
-static int ftpm_tee_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
-{
-       struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
-       size_t len;
-
-       len = pvt_data->resp_len;
-       if (count < len) {
-               dev_err(&chip->dev,
-                       "%s: Invalid size in recv: count=%zd, resp_len=%zd\n",
-                       __func__, count, len);
-               return -EIO;
-       }
-
-       memcpy(buf, pvt_data->resp_buf, len);
-       pvt_data->resp_len = 0;
-
-       return len;
-}
-
-/**
- * ftpm_tee_tpm_op_send() - send TPM commands through the TEE shared memory.
+ * ftpm_tee_tpm_op_send() - send TPM commands through the TEE shared memory
+ * and retrieve the response.
  * @chip:      the tpm_chip description as specified in driver/char/tpm/tpm.h
- * @buf:       the buffer to send.
+ * @buf:       the buffer to send and to store the response.
  * @bufsiz:    the size of the buffer.
- * @len:       the number of bytes to send.
+ * @cmd_len:   the number of bytes to send.
  *
  * Return:
- *     In case of success, returns 0.
+ *     In case of success, returns the number of bytes received.
  *     On failure, -errno
  */
 static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
-                               size_t len)
+                               size_t cmd_len)
 {
        struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
        size_t resp_len;
@@ -82,16 +54,15 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
        struct tee_param command_params[4];
        struct tee_shm *shm = pvt_data->shm;
 
-       if (len > MAX_COMMAND_SIZE) {
+       if (cmd_len > MAX_COMMAND_SIZE) {
                dev_err(&chip->dev,
                        "%s: len=%zd exceeds MAX_COMMAND_SIZE supported by fTPM TA\n",
-                       __func__, len);
+                       __func__, cmd_len);
                return -EIO;
        }
 
        memset(&transceive_args, 0, sizeof(transceive_args));
        memset(command_params, 0, sizeof(command_params));
-       pvt_data->resp_len = 0;
 
        /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */
        transceive_args = (struct tee_ioctl_invoke_arg) {
@@ -105,7 +76,7 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
                .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
                .u.memref = {
                        .shm = shm,
-                       .size = len,
+                       .size = cmd_len,
                        .shm_offs = 0,
                },
        };
@@ -117,7 +88,7 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
                return PTR_ERR(temp_buf);
        }
        memset(temp_buf, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE));
-       memcpy(temp_buf, buf, len);
+       memcpy(temp_buf, buf, cmd_len);
 
        command_params[1] = (struct tee_param) {
                .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT,
@@ -158,17 +129,20 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
                        __func__, resp_len);
                return -EIO;
        }
+       if (resp_len > bufsiz) {
+               dev_err(&chip->dev,
+                       "%s: resp_len=%zd exceeds bufsiz=%zd\n",
+                       __func__, resp_len, bufsiz);
+               return -EIO;
+       }
 
-       /* sanity checks look good, cache the response */
-       memcpy(pvt_data->resp_buf, temp_buf, resp_len);
-       pvt_data->resp_len = resp_len;
+       memcpy(buf, temp_buf, resp_len);
 
-       return 0;
+       return resp_len;
 }
 
 static const struct tpm_class_ops ftpm_tee_tpm_ops = {
        .flags = TPM_OPS_AUTO_STARTUP,
-       .recv = ftpm_tee_tpm_op_recv,
        .send = ftpm_tee_tpm_op_send,
 };
 
@@ -253,7 +227,7 @@ static int ftpm_tee_probe(struct device *dev)
        }
 
        pvt_data->chip = chip;
-       pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2;
+       pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_SYNC;
 
        /* Create a character device for the fTPM */
        rc = tpm_chip_register(pvt_data->chip);

diff --git a/drivers/char/tpm/tpm_ftpm_tee.h b/drivers/char/tpm/tpm_ftpm_tee.h
index e39903b7ea071ea5d9066ae2affe8f370cd33cb6..8d5c3f0d287948dd60f26f3bfe823d163282fa17 100644 (file)
--- a/drivers/char/tpm/tpm_ftpm_tee.h
+++ b/drivers/char/tpm/tpm_ftpm_tee.h
@@ -22,16 +22,12 @@
  * struct ftpm_tee_private - fTPM's private data
  * @chip:     struct tpm_chip instance registered with tpm framework.
  * @session:  fTPM TA session identifier.
- * @resp_len: cached response buffer length.
- * @resp_buf: cached response buffer.
  * @ctx:      TEE context handler.
  * @shm:      Memory pool shared with fTPM TA in TEE.
  */
 struct ftpm_tee_private {
        struct tpm_chip *chip;
        u32 session;
-       size_t resp_len;
-       u8 resp_buf[MAX_RESPONSE_SIZE];
        struct tee_context *ctx;
        struct tee_shm *shm;
 };