iommu/io-pgtable-arm: Fix self-test WARNs on i386

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.wu@intel.com>
Reported-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 5a500edf00cc146805d0a346525e0b9169c816c5..b610a8dee23820573b6362472b4ab5ec31c4003f 100644 (file)
--- 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. */