+ iommu-io-pgtable-arm-v7s-request-dma32-memory-and-improve-debugging.patch added to -mm tree - Linux-stable-mirror

19 Mar 2019

The patch titled
     Subject: iommu/io-pgtable-arm-v7s: request DMA32 memory, and improve debugging
has been added to the -mm tree.  Its filename is
     iommu-io-pgtable-arm-v7s-request-dma32-memory-and-improve-debugging.patch
This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/iommu-io-pgtable-arm-v7s-request-dm...
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/iommu-io-pgtable-arm-v7s-request-dm...
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------------------------------------------------------
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
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: Will Deacon will.deacon@arm.com
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;
_
Patches currently in -mm which might be from drinkcat@chromium.org are
mm-add-support-for-kmem-caches-in-dma32-zone.patch
iommu-io-pgtable-arm-v7s-request-dma32-memory-and-improve-debugging.patch
mm-add-sys-kernel-slab-cache-cache_dma32.patch

    