5128da3235
parisc is the only architecture that sets ARCH_NO_COHERENT_DMA_MMAP when an MMU is enabled. AFAIK this is because parisc CPUs use VIVT caches, which means exporting normally cachable memory to userspace is relatively dangrous due to cache aliasing. But normally cachable memory is only allocated by dma_alloc_coherent on parisc when using the sba_iommu or ccio_iommu drivers, so just remove the .mmap implementation for them so that we don't have to set ARCH_NO_COHERENT_DMA_MMAP, which I plan to get rid of. Signed-off-by: Christoph Hellwig <hch@lst.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.