iommu/io-pgtable-arm-v7s: request DMA32 memory, and improve debugging

IOMMUs using ARMv7 short-descriptor format require page tables (level 1
and 2) to be allocated within the first 4GB of RAM, even on 64-bit
systems.

For level 1/2 pages, ensure GFP_DMA32 is used if CONFIG_ZONE_DMA32 is
defined (e.g.  on arm64 platforms).

For level 2 pages, allocate a slab cache in SLAB_CACHE_DMA32.  Note that
we do not explicitly pass GFP_DMA[32] to kmem_cache_zalloc, as this is
not strictly necessary, and would cause a warning in mm/sl*b.c, as we
did not update GFP_SLAB_BUG_MASK.

Also, print an error when the physical address does not fit in
32-bit, to make debugging easier in the future.

Link: http://lkml.kernel.org/r/20181210011504.122604-3-drinkcat@chromium.org


Fixes: ad67f5a6 ("arm64: replace ZONE_DMA with ZONE_DMA32")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Huaisheng Ye <yehs1@lenovo.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sasha Levin <Alexander.Levin@microsoft.com>
Cc: Tomasz Figa <tfiga@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yong Wu <yong.wu@mediatek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>