lkml.org 
[lkml]   [2018]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v5 2/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging
Date
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.

Fixes: ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
---

Changes since v2:
- Commit message

(v3 used the page_frag approach)

Changes since v4:
- Do not pass ARM_V7S_TABLE_GFP_DMA to kmem_cache_zalloc, as this
is unnecessary, and would trigger a warning.

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

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 445c3bde04800c..f311fe1dfa47b7 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -161,6 +161,14 @@

#define ARM_V7S_TCR_PD1 BIT(5)

+#ifdef CONFIG_ZONE_DMA32
+#define ARM_V7S_TABLE_GFP_DMA GFP_DMA32
+#define ARM_V7S_TABLE_SLAB_CACHE SLAB_CACHE_DMA32
+#else
+#define ARM_V7S_TABLE_GFP_DMA GFP_DMA
+#define ARM_V7S_TABLE_SLAB_CACHE SLAB_CACHE_DMA
+#endif
+
typedef u32 arm_v7s_iopte;

static bool selftest_running;
@@ -198,13 +206,16 @@ 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))
@@ -737,7 +748,7 @@ 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_CACHE, NULL);
if (!data->l2_tables)
goto out_free_data;

--
2.20.0.rc2.403.gdbc3b29805-goog
\
 
 \ /
  Last update: 2018-12-07 07:17    [W:0.087 / U:0.412 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site