Various build/boot bots have reported WARNs being triggered by the ARM
iopgtable LPAE self-tests on i386 machines.
This boils down to two instances of right-shifting a 32-bit unsigned
long (i.e. an iova) by more than the size of the type. On 32-bit ARM,
this happens to give us zero, hence my testing didn't catch this
earlier.
This patch fixes the issue by using DIV_ROUND_UP and explicit case to
to avoid the erroneous shifts.
Reported-by: Fengguang Wu <fengguang...@intel.com>
Reported-by: Huang Ying <ying.hu...@intel.com>
Signed-off-by: Will Deacon <will.dea...@arm.com>
---
Joerg -- please can you apply this as a fix for 3.20?
drivers/iommu/io-pgtable-arm.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 5a500edf00cc..b610a8dee238 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -56,7 +56,8 @@
((((d)->levels - ((l) - ARM_LPAE_START_LVL(d) + 1)) \
* (d)->bits_per_level) + (d)->pg_shift)
-#define ARM_LPAE_PAGES_PER_PGD(d) ((d)->pgd_size >> (d)->pg_shift)
+#define ARM_LPAE_PAGES_PER_PGD(d) \
+ DIV_ROUND_UP((d)->pgd_size, 1UL << (d)->pg_shift)
/*
* Calculate the index at level l used to map virtual address a using the
@@ -66,7 +67,7 @@
((l) == ARM_LPAE_START_LVL(d) ? ilog2(ARM_LPAE_PAGES_PER_PGD(d)) : 0)
#define ARM_LPAE_LVL_IDX(a,l,d)
\
- (((a) >> ARM_LPAE_LVL_SHIFT(l,d)) & \
+ (((u64)(a) >> ARM_LPAE_LVL_SHIFT(l,d)) & \
((1 << ((d)->bits_per_level + ARM_LPAE_PGD_IDX(l,d))) - 1))
/* Calculate the block/page mapping size at level l for pagetable in d. */
--
2.1.4
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