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dma-mapping: add an arch_dma_supported hook 

To implement the x86 forbid_dac and iommu_sac_force we want an arch hook
so that it can apply the global options across all dma_map_ops
implementations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Christoph Hellwig 2017-12-23 11:01:41 +01:00
parent 57bf5a8963
commit cea9d03c82
3 changed files with 26 additions and 7 deletions
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3
arch/x86/include/asm/dma-mapping.h
View File

@ -30,6 +30,9 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
return dma_ops;
}
int arch_dma_supported(struct device *dev, u64 mask);
#define arch_dma_supported arch_dma_supported
bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp);
#define arch_dma_alloc_attrs arch_dma_alloc_attrs

19
arch/x86/kernel/pci-dma.c
View File

@ -215,7 +215,7 @@ static __init int iommu_setup(char *p)
}
early_param("iommu", iommu_setup);
int x86_dma_supported(struct device *dev, u64 mask)
int arch_dma_supported(struct device *dev, u64 mask)
{
#ifdef CONFIG_PCI
if (mask > 0xffffffff && forbid_dac > 0) {
@ -224,12 +224,6 @@ int x86_dma_supported(struct device *dev, u64 mask)
}
#endif
/* Copied from i386. Doesn't make much sense, because it will
only work for pci_alloc_coherent.
The caller just has to use GFP_DMA in this case. */
if (mask < DMA_BIT_MASK(24))
return 0;
/* Tell the device to use SAC when IOMMU force is on. This
allows the driver to use cheaper accesses in some cases.
@ -249,6 +243,17 @@ int x86_dma_supported(struct device *dev, u64 mask)
return 1;
}
EXPORT_SYMBOL(arch_dma_supported);
int x86_dma_supported(struct device *dev, u64 mask)
{
/* Copied from i386. Doesn't make much sense, because it will
only work for pci_alloc_coherent.
The caller just has to use GFP_DMA in this case. */
if (mask < DMA_BIT_MASK(24))
return 0;
return 1;
}
static int __init pci_iommu_init(void)
{

11
include/linux/dma-mapping.h
View File

@ -576,6 +576,14 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
return 0;
}
/*
* This is a hack for the legacy x86 forbid_dac and iommu_sac_force. Please
* don't use this is new code.
*/
#ifndef arch_dma_supported
#define arch_dma_supported(dev, mask) (1)
#endif
static inline void dma_check_mask(struct device *dev, u64 mask)
{
if (sme_active() && (mask < (((u64)sme_get_me_mask() << 1) - 1)))
@ -588,6 +596,9 @@ static inline int dma_supported(struct device *dev, u64 mask)
if (!ops)
return 0;
if (!arch_dma_supported(dev, mask))
return 0;
if (!ops->dma_supported)
return 1;
return ops->dma_supported(dev, mask);