• Haggai Abramovsky's avatar
    net/mlx4: Avoid wrong virtual mappings · 73898db0
    Haggai Abramovsky authored
    The dma_alloc_coherent() function returns a virtual address which can
    be used for coherent access to the underlying memory.  On some
    architectures, like arm64, undefined behavior results if this memory is
    also accessed via virtual mappings that are not coherent.  Because of
    their undefined nature, operations like virt_to_page() return garbage
    when passed virtual addresses obtained from dma_alloc_coherent().  Any
    subsequent mappings via vmap() of the garbage page values are unusable
    and result in bad things like bus errors (synchronous aborts in ARM64
    The mlx4 driver contains code that does the equivalent of:
    vmap(virt_to_page(dma_alloc_coherent)), this results in an OOPs when the
    device is opened.
    Prevent Ethernet driver to run this problematic code by forcing it to
    allocate contiguous memory. As for the Infiniband driver, at first we
    are trying to allocate contiguous memory, but in case of failure roll
    back to work with fragmented memory.
    Signed-off-by: default avatarHaggai Abramovsky <hagaya@mellanox.com>
    Signed-off-by: default avatarYishai Hadas <yishaih@mellanox.com>
    Reported-by: default avatarDavid Daney <david.daney@cavium.com>
    Tested-by: default avatarSinan Kaya <okaya@codeaurora.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>