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Commit b9bc10e9 authored by Jordan Crouse's avatar Jordan Crouse
Browse files

iommu: io-pgtable-arm: Fix unmap optimization for pagetable boundaries 



The last level optimization for __arm_lpae_unmap assumes that
consecutive blocks of 2MB addresses are located in the same
1GB mapping but this isn't always true - if the address spans
a 1GB boundary the next iova is in a different pagetable.

Only perform the optimization for the current pagetable entry and
then kick it back for the loop in arm_lpae_unmap to try again
with the updated iova.  All this means that __arm_lpae_unmap may
not unmap all of the size that it was given. This is okay assuming
at least something was unmapped so don't jump out of the loop
in arm_lpae_unmap until the child function returns 0 or the entire
block is freed, whichever comes first.

CRs-Fixed: 867143
Change-Id: Ic0dedbad407d60365a95afdaf03ec3b91f53960d
Signed-off-by: default avatarJordan Crouse <jcrouse@codeaurora.org>
parent cdecac51

drivers/iommu/io-pgtable-arm.c

+16 −25
Original line number Diff line number Diff line
@@ -494,36 +494,27 @@ static int __arm_lpae_unmap(struct arm_lpae_io_pgtable *data, 


		return size;

	} else if ((lvl == ARM_LPAE_MAX_LEVELS - 2) && !iopte_leaf(pte, lvl)) {

		size_t remaining = size;

		arm_lpae_iopte *table = iopte_deref(pte, data);

		int tl_offset = ARM_LPAE_LVL_IDX(iova, lvl + 1, data);

		int entry_size = (1 << data->pg_shift);

		int max_entries = ARM_LPAE_BLOCK_SIZE(lvl, data) / entry_size;

		int entries = min_t(int, size / entry_size,

			max_entries - tl_offset);

		int table_len = entries * sizeof(*table);



		/*

		 * This isn't a block mapping so it must be a table mapping

		 * and since it's the 2nd-to-last level the next level has

		 * to be all page mappings.  Zero them all out in one fell

		 * swoop.

		 */

		for (;;) {

			arm_lpae_iopte *table = iopte_deref(pte, data);

			int table_len;

			size_t unmapped;

			int tl_offset = ARM_LPAE_LVL_IDX(iova, lvl + 1, data);

			int entry_size = (1 << data->pg_shift);

			int max_entries =

				ARM_LPAE_BLOCK_SIZE(lvl, data) / entry_size;

			int entries = min_t(int, remaining / entry_size,

					    max_entries - tl_offset);



		table += tl_offset;

			table_len = entries * sizeof(*table);



		memset(table, 0, table_len);

		tlb->flush_pgtable(table, table_len, cookie);

			unmapped = entries * entry_size;

			iova += unmapped;

			remaining -= unmapped;

			if (!remaining)

				break;

			pte = *++ptep;

		}

		return size;



		return entries * entry_size;

	} else if (iopte_leaf(pte, lvl)) {

		/*

		 * Insert a table at the next level to map the old region,
@@ -556,7 +547,7 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova, 
			? remaining

			: iommu_pgsize(data->iop.cfg.pgsize_bitmap, iova, size);

		ret = __arm_lpae_unmap(data, iova, size_to_unmap, lvl, ptep);

		if (ret != size_to_unmap)

		if (ret == 0)

			break;

		unmapped += ret;

		iova += ret;