* [PATCH RESEND v3 1/2] tpm_tis_spi: Use DMA-safe memory for SPI transfers
2017-08-31 16:58 [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Alexander Steffen
@ 2017-08-31 16:58 ` Alexander Steffen
2017-08-31 16:58 ` [PATCH RESEND v3 2/2] tpm_tis_spi: Use a single buffer " Alexander Steffen
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Alexander Steffen @ 2017-08-31 16:58 UTC (permalink / raw)
To: jarkko.sakkinen, tpmdd-devel, benoit.houyere
Cc: linux-kernel, linux-security-module, Alexander Steffen, stable
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 <Alexander.Steffen@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH RESEND v3 2/2] tpm_tis_spi: Use a single buffer for SPI transfers
2017-08-31 16:58 [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Alexander Steffen
2017-08-31 16:58 ` [PATCH RESEND v3 1/2] tpm_tis_spi: Use DMA-safe memory for SPI transfers Alexander Steffen
@ 2017-08-31 16:58 ` Alexander Steffen
2017-09-02 10:54 ` [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Jarkko Sakkinen
2017-09-06 12:54 ` Jarkko Sakkinen
3 siblings, 0 replies; 6+ messages in thread
From: Alexander Steffen @ 2017-08-31 16:58 UTC (permalink / raw)
To: jarkko.sakkinen, tpmdd-devel, benoit.houyere
Cc: linux-kernel, linux-security-module, Alexander Steffen
A single buffer is sufficient for both tx and rx, since bytes that have
already been sent are not used anymore and can safely be overwritten with
the received bytes.
Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
drivers/char/tpm/tpm_tis_spi.c | 34 ++++++++++++++--------------------
1 file changed, 14 insertions(+), 20 deletions(-)
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
index 05ce841..5321245 100644
--- a/drivers/char/tpm/tpm_tis_spi.c
+++ b/drivers/char/tpm/tpm_tis_spi.c
@@ -46,9 +46,7 @@
struct tpm_tis_spi_phy {
struct tpm_tis_data priv;
struct spi_device *spi_device;
-
- u8 *tx_buf;
- u8 *rx_buf;
+ u8 *iobuf;
};
static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
@@ -71,14 +69,14 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
while (len) {
transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
- phy->tx_buf[0] = direction | (transfer_len - 1);
- phy->tx_buf[1] = 0xd4;
- phy->tx_buf[2] = addr >> 8;
- phy->tx_buf[3] = addr;
+ phy->iobuf[0] = direction | (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;
@@ -88,9 +86,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
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;
@@ -99,7 +97,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
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;
}
@@ -117,7 +115,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
spi_xfer.tx_buf = NULL;
} else {
spi_xfer.rx_buf = NULL;
- memcpy(phy->tx_buf, buffer, transfer_len);
+ memcpy(phy->iobuf, buffer, transfer_len);
}
spi_message_init(&m);
@@ -127,7 +125,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
goto exit;
if (direction)
- memcpy(buffer, phy->rx_buf, transfer_len);
+ memcpy(buffer, phy->iobuf, transfer_len);
len -= transfer_len;
buffer += transfer_len;
@@ -196,12 +194,8 @@ 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)
+ 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,
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory
2017-08-31 16:58 [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Alexander Steffen
2017-08-31 16:58 ` [PATCH RESEND v3 1/2] tpm_tis_spi: Use DMA-safe memory for SPI transfers Alexander Steffen
2017-08-31 16:58 ` [PATCH RESEND v3 2/2] tpm_tis_spi: Use a single buffer " Alexander Steffen
@ 2017-09-02 10:54 ` Jarkko Sakkinen
2017-09-06 12:54 ` Jarkko Sakkinen
3 siblings, 0 replies; 6+ messages in thread
From: Jarkko Sakkinen @ 2017-09-02 10:54 UTC (permalink / raw)
To: Alexander Steffen
Cc: tpmdd-devel, benoit.houyere, linux-kernel, linux-security-module
On Thu, Aug 31, 2017 at 06:58:17PM +0200, Alexander Steffen wrote:
> The documentation says that DMA-safe memory is required for SPI transfers.
> The I/O buffers passed in by the caller can be allocated anywhere,
> including on the stack, which is not DMA-safe. So the data needs to be
> copied to separate, DMA-safe buffers.
>
> We did not see any DMA-related issues on our test systems, even without
> DMA-safe buffers. But this might simply be due to the fact that the SPI
> transfer size is rather small, so our systems do not bother to set up DMA
> transfers. Other systems might do so.
>
> v2:
> - Updated commit message with more explanations.
>
> v3:
> - Split into two patches, one for making the buffers DMA-safe and another
> for using only a single buffer.
>
> Alexander Steffen (2):
> tpm_tis_spi: Use DMA-safe memory for SPI transfers
> tpm_tis_spi: Use a single buffer for SPI transfers
>
> drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++--------------
> 1 file changed, 18 insertions(+), 14 deletions(-)
>
> --
> 2.7.4
>
Great, I'll try to get means to test this!
/Jarkko
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory
2017-08-31 16:58 [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Alexander Steffen
` (2 preceding siblings ...)
2017-09-02 10:54 ` [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory Jarkko Sakkinen
@ 2017-09-06 12:54 ` Jarkko Sakkinen
2017-09-08 12:11 ` Jarkko Sakkinen
3 siblings, 1 reply; 6+ messages in thread
From: Jarkko Sakkinen @ 2017-09-06 12:54 UTC (permalink / raw)
To: Alexander Steffen
Cc: tpmdd-devel, benoit.houyere, linux-kernel, linux-security-module
On Thu, Aug 31, 2017 at 06:58:17PM +0200, Alexander Steffen wrote:
> The documentation says that DMA-safe memory is required for SPI transfers.
> The I/O buffers passed in by the caller can be allocated anywhere,
> including on the stack, which is not DMA-safe. So the data needs to be
> copied to separate, DMA-safe buffers.
>
> We did not see any DMA-related issues on our test systems, even without
> DMA-safe buffers. But this might simply be due to the fact that the SPI
> transfer size is rather small, so our systems do not bother to set up DMA
> transfers. Other systems might do so.
>
> v2:
> - Updated commit message with more explanations.
>
> v3:
> - Split into two patches, one for making the buffers DMA-safe and another
> for using only a single buffer.
>
> Alexander Steffen (2):
> tpm_tis_spi: Use DMA-safe memory for SPI transfers
> tpm_tis_spi: Use a single buffer for SPI transfers
>
> drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++--------------
> 1 file changed, 18 insertions(+), 14 deletions(-)
>
> --
> 2.7.4
>
Applied to my bleeding edge master brach for more convenient testing.
Have not yet applied to my next branch.
/Jarkko
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory
2017-09-06 12:54 ` Jarkko Sakkinen
@ 2017-09-08 12:11 ` Jarkko Sakkinen
0 siblings, 0 replies; 6+ messages in thread
From: Jarkko Sakkinen @ 2017-09-08 12:11 UTC (permalink / raw)
To: Alexander Steffen
Cc: tpmdd-devel, benoit.houyere, linux-kernel, linux-security-module
On Wed, Sep 06, 2017 at 03:54:58PM +0300, Jarkko Sakkinen wrote:
> On Thu, Aug 31, 2017 at 06:58:17PM +0200, Alexander Steffen wrote:
> > The documentation says that DMA-safe memory is required for SPI transfers.
> > The I/O buffers passed in by the caller can be allocated anywhere,
> > including on the stack, which is not DMA-safe. So the data needs to be
> > copied to separate, DMA-safe buffers.
> >
> > We did not see any DMA-related issues on our test systems, even without
> > DMA-safe buffers. But this might simply be due to the fact that the SPI
> > transfer size is rather small, so our systems do not bother to set up DMA
> > transfers. Other systems might do so.
> >
> > v2:
> > - Updated commit message with more explanations.
> >
> > v3:
> > - Split into two patches, one for making the buffers DMA-safe and another
> > for using only a single buffer.
> >
> > Alexander Steffen (2):
> > tpm_tis_spi: Use DMA-safe memory for SPI transfers
> > tpm_tis_spi: Use a single buffer for SPI transfers
> >
> > drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++--------------
> > 1 file changed, 18 insertions(+), 14 deletions(-)
> >
> > --
> > 2.7.4
> >
>
> Applied to my bleeding edge master brach for more convenient testing.
> Have not yet applied to my next branch.
>
> /Jarkko
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
My XP13 happened to have suitable TPM.
/Jarkko
^ permalink raw reply [flat|nested] 6+ messages in thread