• Will Deacon's avatar
    iommu/arm-smmu: Fix CMDQ error handling · aef62956
    Will Deacon authored
    commit aea2037e upstream.
    
    In the unlikely event of a global command queue error, the ARM SMMUv3
    driver attempts to convert the problematic command into a CMD_SYNC and
    resume the command queue. Unfortunately, this code is pretty badly
    broken:
    
      1. It uses the index into the error string table as the CMDQ index,
         so we probably read the wrong entry out of the queue
    
      2. The arguments to queue_write are the wrong way round, so we end up
         writing from the queue onto the stack.
    
    These happily cancel out, so the kernel is likely to stay alive, but
    the command queue will probably fault again when we resume.
    
    This patch fixes the error handling code to use the correct queue index
    and write back the CMD_SYNC to the faulting entry.
    
    Fixes: 48ec83bc ("iommu/arm-smmu: Add initial driver support for ARM SMMUv3 devices")
    Reported-by: default avatarDiwakar Subraveti <Diwakar.Subraveti@arm.com>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    aef62956
arm-smmu-v3.c 70.1 KB