From mboxrd@z Thu Jan 1 00:00:00 1970 From: jarkko.sakkinen@linux.intel.com (Jarkko Sakkinen) Date: Fri, 8 Sep 2017 15:11:22 +0300 Subject: [PATCH RESEND v3 0/2] tpm_tis_spi: Use DMA-safe memory In-Reply-To: <20170906125458.ueqpmokh7bg64olc@linux.intel.com> References: <20170831165819.13544-1-Alexander.Steffen@infineon.com> <20170906125458.ueqpmokh7bg64olc@linux.intel.com> Message-ID: <20170908121122.2frkkcoidoc3u7g2@linux.intel.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org 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 My XP13 happened to have suitable TPM. /Jarkko -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html