[PATCH kernel v6 10/29] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE
From: Alexey Kardashevskiy <hidden>
Date: 2015-03-13 08:10:09
Also in:
kvm, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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. 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 <redacted> --- arch/powerpc/include/asm/iommu.h | 1 + arch/powerpc/kernel/iommu.c | 15 +++++++++++++++ arch/powerpc/platforms/powernv/pci.c | 7 +------ 3 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index ed69b7d..2af2d70 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h@@ -203,6 +203,7 @@ extern int iommu_take_ownership(struct iommu_table *tbl); extern void iommu_release_ownership(struct iommu_table *tbl); extern enum dma_data_direction iommu_tce_direction(unsigned long tce); +extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir); #endif /* __KERNEL__ */ #endif /* _ASM_IOMMU_H */
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 1b4a178..865beef 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c@@ -916,6 +916,21 @@ enum dma_data_direction iommu_tce_direction(unsigned long tce) } EXPORT_SYMBOL_GPL(iommu_tce_direction); +unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir) +{ + switch (dir) { + case DMA_BIDIRECTIONAL: + return TCE_PCI_READ | TCE_PCI_WRITE; + case DMA_FROM_DEVICE: + return TCE_PCI_WRITE; + case DMA_TO_DEVICE: + return TCE_PCI_READ; + default: + return 0; + } +} +EXPORT_SYMBOL_GPL(iommu_direction_to_tce_perm); + void iommu_flush_tce(struct iommu_table *tbl) { /* Flush/invalidate TLB caches if necessary */
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 54323d6..609f5b1 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c@@ -593,15 +593,10 @@ static int pnv_tce_build(struct iommu_table *tbl, long index, long npages, unsigned long uaddr, enum dma_data_direction direction, struct dma_attrs *attrs, bool rm) { - u64 proto_tce; + u64 proto_tce = iommu_direction_to_tce_perm(direction); __be64 *tcep, *tces; u64 rpn; - proto_tce = TCE_PCI_READ; // Read allowed - - if (direction != DMA_TO_DEVICE) - proto_tce |= TCE_PCI_WRITE; - tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset; rpn = __pa(uaddr) >> tbl->it_page_shift;
--
2.0.0