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/[email protected]
Fixes: ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32")
Signed-off-by: Nicolas Boichat <[email protected]>
Acked-by: Will Deacon <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Hsin-Yi Wang <[email protected]>
Cc: Huaisheng Ye <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Tomasz Figa <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Yingjoe Chen <[email protected]>
Cc: Yong Wu <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index f101afc315abb8da199fa1a9d2bd4df3d44d82e9..9a8a8870e26727e7398afffd5286860b0e8581d9 100644 (file)
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/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 lvl, gfp_t gfp,
        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_pgtable(struct io_pgtable_cfg *cfg,
        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;