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Wed, 30 Apr 2025 15:47:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746028076; bh=f9vaf9DxyD8z2Q/o/BFiff3Umf0tnskp9fmVY7CIEio=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FXBvLp6VaHaLbGjkaQGyLkJzrWelTgowFyf6dEbcMDnAPXlZFroKnPnvlVGddJGql GhFs0xAfajb4Gjn468c0b9R/xF1Flcij0QP0dpVVvwrImu3E6kKQGaAE9CKzZPUhBK oAq8kC9DYOEDDN9iGyapTrEkeFf7wQi6xVgepEk9AdukT/N0DN4UnRjV6ZjO1ErRUz GUeL37ZEeI0+L6OP1xzXkZ19/C8OO31TyU9KexphopScF3vqgyu4Oj2kuZ9NVicrqU /0OroxEC5eN/dE3orF050V8wyyh24kcf9Ij5nCUXTqZOQ9srxGAkKtLxl8eExN0GTo ZdRXDxOc+IKRw== Date: Wed, 30 Apr 2025 18:47:51 +0300 From: Jarkko Sakkinen To: Stefano Garzarella Cc: Christophe Leroy , Peter Huewe , Alexandre Belloni , Jens Wiklander , Claudiu Beznea , Naveen N Rao , Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Nicolas Ferre , Michael Ellerman , Madhavan Srinivasan , James Bottomley , linux-integrity@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sumit Garg , linux-kernel@vger.kernel.org, Jason Gunthorpe Subject: Re: [PATCH v3 3/4] tpm/tpm_ftpm_tee: support TPM_CHIP_FLAG_SYNC Message-ID: References: <20250414145653.239081-1-sgarzare@redhat.com> <20250414145653.239081-4-sgarzare@redhat.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250414145653.239081-4-sgarzare@redhat.com> On Mon, Apr 14, 2025 at 04:56:52PM +0200, Stefano Garzarella wrote: > From: Stefano Garzarella > > This driver does not support interrupts, and receiving the response is > synchronous with sending the command. > > So we can set TPM_CHIP_FLAG_SYNC to support synchronous send() and "Enable synchronous send() with TPM_CHIP_FLAG_SYNC, which implies that ->send() already fills the provided buffer with a reponse, and ->recv() is not implemented." So, instead of jargon it is better to explicitly state what the heck is going on. > return responses in the same buffer used for commands. This way we > don't need the 4KB internal buffer used to cache the response before > .send() and .recv(). Also we don't need to implement recv() op. > > Signed-off-by: Stefano Garzarella > --- > v2: > - set TPM_CHIP_FLAG_SYNC and support it in the new send() > - removed Jens' T-b > v1: > - added Jens' T-b > --- > drivers/char/tpm/tpm_ftpm_tee.h | 4 --- > drivers/char/tpm/tpm_ftpm_tee.c | 64 ++++++++++----------------------- > 2 files changed, 19 insertions(+), 49 deletions(-) > > diff --git a/drivers/char/tpm/tpm_ftpm_tee.h b/drivers/char/tpm/tpm_ftpm_tee.h > index e39903b7ea07..8d5c3f0d2879 100644 > --- 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; > }; > diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c > index 637cc8b6599e..b9adc040ca6d 100644 > --- a/drivers/char/tpm/tpm_ftpm_tee.c > +++ b/drivers/char/tpm/tpm_ftpm_tee.c > @@ -31,46 +31,18 @@ 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. > - * @len: the number of bytes to send. > + * @buf: the buffer to send and to store the response. > + * @cmd_len: the number of bytes to send. > * @buf_size: the size of the buffer. > * > * 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 len, > +static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t cmd_len, > size_t buf_size) > { > struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent); > @@ -82,16 +54,15 @@ static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len, > 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 len, > .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 len, > 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 len, > __func__, resp_len); > return -EIO; > } > + if (resp_len > buf_size) { > + dev_err(&chip->dev, > + "%s: resp_len=%zd exceeds buf_size=%zd\n", > + __func__, resp_len, buf_size); > + 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); > -- > 2.49.0 > BR, Jarkko