From: Nicolas Boichat drinkcat@chromium.org Subject: 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: ad67f5a6545f ("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 ---

drivers/iommu/io-pgtable-arm-v7s.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)

--- a/drivers/iommu/io-pgtable-arm-v7s.c~iommu-io-pgtable-arm-v7s-request-dma32-memory-and-improve-debugging +++ a/drivers/iommu/io-pgtable-arm-v7s.c @@ -160,6 +160,14 @@

#define ARM_V7S_TCR_PD1 BIT(5)

+#ifdef CONFIG_ZONE_DMA32 +#define ARM_V7S_TABLE_GFP_DMA GFP_DMA32 +#define ARM_V7S_TABLE_SLAB_FLAGS SLAB_CACHE_DMA32 +#else +#define ARM_V7S_TABLE_GFP_DMA GFP_DMA +#define ARM_V7S_TABLE_SLAB_FLAGS SLAB_CACHE_DMA +#endif + typedef u32 arm_v7s_iopte;

static bool selftest_running; @@ -197,13 +205,16 @@ static void *__arm_v7s_alloc_table(int l void *table = NULL;

if (lvl == 1) - table = (void *)__get_dma_pages(__GFP_ZERO, get_order(size)); + table = (void *)__get_free_pages( + __GFP_ZERO | ARM_V7S_TABLE_GFP_DMA, get_order(size)); else if (lvl == 2) - table = kmem_cache_zalloc(data->l2_tables, gfp | GFP_DMA); + table = kmem_cache_zalloc(data->l2_tables, gfp); phys = virt_to_phys(table); - if (phys != (arm_v7s_iopte)phys) + if (phys != (arm_v7s_iopte)phys) { /* Doesn't fit in PTE */ + dev_err(dev, "Page table does not fit in PTE: %pa", &phys); goto out_free; + } if (table && !(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA)) { dma = dma_map_single(dev, table, size, DMA_TO_DEVICE); if (dma_mapping_error(dev, dma)) @@ -733,7 +744,7 @@ static struct io_pgtable *arm_v7s_alloc_ data->l2_tables = kmem_cache_create("io-pgtable_armv7s_l2", ARM_V7S_TABLE_SIZE(2), ARM_V7S_TABLE_SIZE(2), - SLAB_CACHE_DMA, NULL); + ARM_V7S_TABLE_SLAB_FLAGS, NULL); if (!data->l2_tables) goto out_free_data;

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