diff options
| author | Will Deacon <will@kernel.org> | 2021-06-16 16:38:46 +0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-07-26 13:37:07 +0300 |
| commit | e7d6fff6b3d34230bac1b2c2607646d7b8638cb7 (patch) | |
| tree | 020f9f45d89f6343b0cec7ba27b0f2b6c4f31a55 /drivers/iommu/iommu.c | |
| parent | 910c4406ccc9613de0a54abf910edc4bf8a575c0 (diff) | |
| download | linux-e7d6fff6b3d34230bac1b2c2607646d7b8638cb7.tar.xz | |
iommu: Use bitmap to calculate page size in iommu_pgsize()
Avoid the potential for shifting values by amounts greater than the
width of their type by using a bitmap to compute page size in
iommu_pgsize().
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1623850736-389584-6-git-send-email-quic_c_gdjako@quicinc.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/iommu.c')
| -rw-r--r-- | drivers/iommu/iommu.c | 31 |
1 files changed, 12 insertions, 19 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 5419c4b9f27a..80e471ada358 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -8,6 +8,7 @@ #include <linux/device.h> #include <linux/kernel.h> +#include <linux/bits.h> #include <linux/bug.h> #include <linux/types.h> #include <linux/init.h> @@ -2378,30 +2379,22 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long addr_merge, size_t size) { unsigned int pgsize_idx; + unsigned long pgsizes; size_t pgsize; - /* Max page size that still fits into 'size' */ - pgsize_idx = __fls(size); + /* Page sizes supported by the hardware and small enough for @size */ + pgsizes = domain->pgsize_bitmap & GENMASK(__fls(size), 0); - /* need to consider alignment requirements ? */ - if (likely(addr_merge)) { - /* Max page size allowed by address */ - unsigned int align_pgsize_idx = __ffs(addr_merge); - pgsize_idx = min(pgsize_idx, align_pgsize_idx); - } - - /* build a mask of acceptable page sizes */ - pgsize = (1UL << (pgsize_idx + 1)) - 1; - - /* throw away page sizes not supported by the hardware */ - pgsize &= domain->pgsize_bitmap; + /* Constrain the page sizes further based on the maximum alignment */ + if (likely(addr_merge)) + pgsizes &= GENMASK(__ffs(addr_merge), 0); - /* make sure we're still sane */ - BUG_ON(!pgsize); + /* Make sure we have at least one suitable page size */ + BUG_ON(!pgsizes); - /* pick the biggest page */ - pgsize_idx = __fls(pgsize); - pgsize = 1UL << pgsize_idx; + /* Pick the biggest page size remaining */ + pgsize_idx = __fls(pgsizes); + pgsize = BIT(pgsize_idx); return pgsize; } |