On Mon, Dec 10, 2018 at 09:15:03AM +0800, Nicolas Boichat wrote:

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.

Cc: stable@vger.kernel.org
Fixes: ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32")
Signed-off-by: Nicolas Boichat <redacted>

Assuming you're routing all of this via akpm:

Acked-by: Will Deacon <redacted>

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel