From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Steffen Subject: [PATCH RESEND v3 1/2] tpm_tis_spi: Use DMA-safe memory for SPI transfers Date: Thu, 31 Aug 2017 18:58:18 +0200 Message-ID: <20170831165819.13544-2-Alexander.Steffen@infineon.com> References: <20170831165819.13544-1-Alexander.Steffen@infineon.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <20170831165819.13544-1-Alexander.Steffen@infineon.com> Sender: owner-linux-security-module@vger.kernel.org To: jarkko.sakkinen@linux.intel.com, tpmdd-devel@lists.sourceforge.net, benoit.houyere@st.com Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Alexander Steffen , stable@vger.kernel.org List-Id: tpmdd-devel@lists.sourceforge.net The buffers used as tx_buf/rx_buf in a SPI transfer need to be DMA-safe. This cannot be guaranteed for the buffers passed to tpm_tis_spi_read_bytes and tpm_tis_spi_write_bytes. Therefore, we need to use our own DMA-safe buffer and copy the data to/from it. The buffer needs to be allocated separately, to ensure that it is cacheline-aligned and not shared with other data, so that DMA can work correctly. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Cc: stable@vger.kernel.org Signed-off-by: Alexander Steffen Reviewed-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_tis_spi.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 88fe72a..05ce841 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -47,8 +47,8 @@ struct tpm_tis_spi_phy { struct tpm_tis_data priv; struct spi_device *spi_device; - u8 tx_buf[4]; - u8 rx_buf[4]; + u8 *tx_buf; + u8 *rx_buf; }; static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data) @@ -115,10 +115,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (direction) { spi_xfer.tx_buf = NULL; - spi_xfer.rx_buf = buffer; } else { - spi_xfer.tx_buf = buffer; spi_xfer.rx_buf = NULL; + memcpy(phy->tx_buf, buffer, transfer_len); } spi_message_init(&m); @@ -127,6 +126,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; + if (direction) + memcpy(buffer, phy->rx_buf, transfer_len); + len -= transfer_len; buffer += transfer_len; } @@ -194,6 +196,14 @@ static int tpm_tis_spi_probe(struct spi_device *dev) phy->spi_device = dev; + phy->tx_buf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + if (!phy->tx_buf) + return -ENOMEM; + + phy->rx_buf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + if (!phy->rx_buf) + return -ENOMEM; + return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops, NULL); } -- 2.7.4