[PATCH kernel v10 13/34] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE
From: Alexey Kardashevskiy <hidden>
Date: 2015-05-11 15:45:58
Also in:
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 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 <redacted> Reviewed-by: David Gibson <redacted> --- Changes: v9: * added comment why we must put only valid permission bits --- 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 e94a5e3..d91bd69 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h@@ -200,6 +200,7 @@ 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 8673c94..31319f8 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c@@ -863,6 +863,21 @@ void iommu_free_coherent(struct iommu_table *tbl, size_t size, } } +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); + #ifdef CONFIG_IOMMU_API /* * SPAPR TCE API
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index bca2aeb..b7ea245 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c@@ -576,15 +576,10 @@ 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;
--
2.4.0.rc3.8.gfb3e7d5