This is a note to let you know that I've just added the patch titled

tpm_tis_spi: Use DMA-safe memory for SPI transfers

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: tpm_tis_spi-use-dma-safe-memory-for-spi-transfers.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 6b3a13173f23e798e1ba213dd4a2c065a3b8d751 Mon Sep 17 00:00:00 2001

From: Alexander Steffen Alexander.Steffen@infineon.com Date: Mon, 11 Sep 2017 12:26:52 +0200 Subject: tpm_tis_spi: Use DMA-safe memory for SPI transfers

From: Alexander Steffen Alexander.Steffen@infineon.com

commit 6b3a13173f23e798e1ba213dd4a2c065a3b8d751 upstream.

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 Reviewed-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Alexander Steffen Alexander.Steffen@infineon.com Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/char/tpm/tpm_tis_spi.c | 45 ++++++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 18 deletions(-)

--- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -47,9 +47,7 @@ struct tpm_tis_spi_phy { struct tpm_tis_data priv; struct spi_device *spi_device; - - u8 tx_buf[4]; - u8 rx_buf[4]; + u8 *iobuf; };

static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data) @@ -72,14 +70,14 @@ static int tpm_tis_spi_transfer(struct t while (len) { transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);

- phy->tx_buf[0] = (in ? 0x80 : 0) | (transfer_len - 1); - phy->tx_buf[1] = 0xd4; - phy->tx_buf[2] = addr >> 8; - phy->tx_buf[3] = addr; + phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1); + phy->iobuf[1] = 0xd4; + phy->iobuf[2] = addr >> 8; + phy->iobuf[3] = addr;

memset(&spi_xfer, 0, sizeof(spi_xfer)); - spi_xfer.tx_buf = phy->tx_buf; - spi_xfer.rx_buf = phy->rx_buf; + spi_xfer.tx_buf = phy->iobuf; + spi_xfer.rx_buf = phy->iobuf; spi_xfer.len = 4; spi_xfer.cs_change = 1;

@@ -89,9 +87,9 @@ static int tpm_tis_spi_transfer(struct t if (ret < 0) goto exit;

- if ((phy->rx_buf[3] & 0x01) == 0) { + if ((phy->iobuf[3] & 0x01) == 0) { // handle SPI wait states - phy->tx_buf[0] = 0; + phy->iobuf[0] = 0;

for (i = 0; i < TPM_RETRY; i++) { spi_xfer.len = 1; @@ -100,7 +98,7 @@ static int tpm_tis_spi_transfer(struct t ret = spi_sync_locked(phy->spi_device, &m); if (ret < 0) goto exit; - if (phy->rx_buf[0] & 0x01) + if (phy->iobuf[0] & 0x01) break; }

@@ -113,8 +111,14 @@ static int tpm_tis_spi_transfer(struct t spi_xfer.cs_change = 0; spi_xfer.len = transfer_len; spi_xfer.delay_usecs = 5; - spi_xfer.tx_buf = out; - spi_xfer.rx_buf = in; + + if (in) { + spi_xfer.tx_buf = NULL; + } else if (out) { + spi_xfer.rx_buf = NULL; + memcpy(phy->iobuf, out, transfer_len); + out += transfer_len; + }

spi_message_init(&m); spi_message_add_tail(&spi_xfer, &m); @@ -122,11 +126,12 @@ static int tpm_tis_spi_transfer(struct t if (ret < 0) goto exit;

- len -= transfer_len; - if (in) + if (in) { + memcpy(in, phy->iobuf, transfer_len); in += transfer_len; - if (out) - out += transfer_len; + } + + len -= transfer_len; }

exit: @@ -192,6 +197,10 @@ static int tpm_tis_spi_probe(struct spi_

phy->spi_device = dev;

+ phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + if (!phy->iobuf) + return -ENOMEM; + return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops, NULL); }

Patches currently in stable-queue which might be from Alexander.Steffen@infineon.com are

queue-4.9/tpm-dev-common-reject-too-short-writes.patch queue-4.9/tpm_tis_spi-use-dma-safe-memory-for-spi-transfers.patch