[PATCH 21/33] dma-mapping: add an arch_dma_supported hook
From: Christoph Hellwig <hch@lst.de>
Date: 2018-01-10 08:01:46
Also in:
linux-alpha, linux-arch, linux-arm-kernel, linux-iommu, linux-mips, linux-s390, linux-sh, lkml, sparclinux
Subsystem:
dma mapping helpers, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Marek Szyprowski, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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> --- arch/x86/include/asm/dma-mapping.h | 3 +++ arch/x86/kernel/pci-dma.c | 19 ++++++++++++------- include/linux/dma-mapping.h | 11 +++++++++++ 3 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index dfdc9357a349..6277c83c0eb1 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h@@ -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
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 61a8f1cb3829..df7ab02f959f 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c@@ -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) {
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 88bcb1a8211d..d67742dad904 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h@@ -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);
--
2.14.2