powerpc/powernv: Do not set "read" flag if direction==DMA_NONE

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Normally a bitmap from the iommu_table is used to track what TCE entry
is in use. Since we are going to use iommu_table without its locks and
do xchg() instead, it becomes essential not to put bits which are not
implied in the direction flag as the old TCE value (more precisely -
the permission bits) will be used to decide whether to put the page or not.

This adds iommu_direction_to_tce_perm() (its counterpart is there already)
and uses it for powernv's pnv_tce_build().

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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This commit is contained in:

Alexey Kardashevskiy 2015-06-05 16:35:05 +10:00 • committed by Michael Ellerman

parent 22af48596e

commit 10b35b2b74

3 changed files with 17 additions and 6 deletions

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1

arch/powerpc/include/asm/iommu.h

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15

arch/powerpc/kernel/iommu.c

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7

arch/powerpc/platforms/powernv/pci.c

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