From 7641842164c34b672ef3e70e881e8a72735305c1 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 2 Nov 2016 07:12:47 -0400 Subject: swiotlb-xen: Enforce return of DMA_ERROR_CODE in mapping function The mapping function should always return DMA_ERROR_CODE when a mapping has failed as this is what the DMA API expects when a DMA error has occurred. The current function for mapping a page in Xen was returning either DMA_ERROR_CODE or 0 depending on where it failed. On x86 DMA_ERROR_CODE is 0, but on other architectures such as ARM it is ~0. We need to make sure we return the same error value if either the mapping failed or the device is not capable of accessing the mapping. If we are returning DMA_ERROR_CODE as our error value we can drop the function for checking the error code as the default is to compare the return value against DMA_ERROR_CODE if no function is defined. Cc: Konrad Rzeszutek Wilk Signed-off-by: Alexander Duyck Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/swiotlb-xen.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 87e6035c9e81..b8014bf2b2ed 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -416,11 +416,12 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, /* * Ensure that the address returned is DMA'ble */ - if (!dma_capable(dev, dev_addr, size)) { - swiotlb_tbl_unmap_single(dev, map, size, dir); - dev_addr = 0; - } - return dev_addr; + if (dma_capable(dev, dev_addr, size)) + return dev_addr; + + swiotlb_tbl_unmap_single(dev, map, size, dir); + + return DMA_ERROR_CODE; } EXPORT_SYMBOL_GPL(xen_swiotlb_map_page); @@ -648,13 +649,6 @@ xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, } EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device); -int -xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr) -{ - return !dma_addr; -} -EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error); - /* * Return whether the given device DMA address mask can be supported * properly. For example, if your device can only drive the low 24-bits -- cgit v1.2.3 From 0443fa003fa199f41bfbed3012f314d02c5b1f24 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Wed, 2 Nov 2016 07:13:02 -0400 Subject: swiotlb: Add support for DMA_ATTR_SKIP_CPU_SYNC As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures beyond just ARM I need to make it so that the swiotlb will respect the flag. In order to do that I also need to update the swiotlb-xen since it heavily makes use of the functionality. Cc: Konrad Rzeszutek Wilk Signed-off-by: Alexander Duyck Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/swiotlb-xen.c | 11 +++++---- include/linux/swiotlb.h | 6 +++-- lib/swiotlb.c | 59 ++++++++++++++++++++++++++++++----------------- 3 files changed, 49 insertions(+), 27 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index b8014bf2b2ed..3d048afcee38 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -405,7 +405,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, */ trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); - map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir); + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir, + attrs); if (map == SWIOTLB_MAP_ERROR) return DMA_ERROR_CODE; @@ -419,7 +420,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, if (dma_capable(dev, dev_addr, size)) return dev_addr; - swiotlb_tbl_unmap_single(dev, map, size, dir); + swiotlb_tbl_unmap_single(dev, map, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); return DMA_ERROR_CODE; } @@ -445,7 +447,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, /* NOTE: We use dev_addr here, not paddr! */ if (is_xen_swiotlb_buffer(dev_addr)) { - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); return; } @@ -558,11 +560,12 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, start_dma_addr, sg_phys(sg), sg->length, - dir); + dir, attrs); if (map == SWIOTLB_MAP_ERROR) { dev_warn(hwdev, "swiotlb buffer is full\n"); /* Don't panic here, we expect map_sg users to do proper error handling. */ + attrs |= DMA_ATTR_SKIP_CPU_SYNC; xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, attrs); sg_dma_len(sgl) = 0; diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index f0d258967869..183f37c8a5e1 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -44,11 +44,13 @@ enum dma_sync_target { extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, phys_addr_t phys, size_t size, - enum dma_data_direction dir); + enum dma_data_direction dir, + unsigned long attrs); extern void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, - size_t size, enum dma_data_direction dir); + size_t size, enum dma_data_direction dir, + unsigned long attrs); extern void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, diff --git a/lib/swiotlb.c b/lib/swiotlb.c index bdcc0d8a7405..8e883c762728 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -425,7 +425,8 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, phys_addr_t orig_addr, size_t size, - enum dma_data_direction dir) + enum dma_data_direction dir, + unsigned long attrs) { unsigned long flags; phys_addr_t tlb_addr; @@ -526,7 +527,8 @@ found: */ for (i = 0; i < nslots; i++) io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT); - if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && + (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE); return tlb_addr; @@ -539,18 +541,20 @@ EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single); static phys_addr_t map_single(struct device *hwdev, phys_addr_t phys, size_t size, - enum dma_data_direction dir) + enum dma_data_direction dir, unsigned long attrs) { dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start); - return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir); + return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, + dir, attrs); } /* * dma_addr is the kernel virtual address of the bounce buffer to unmap. */ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, - size_t size, enum dma_data_direction dir) + size_t size, enum dma_data_direction dir, + unsigned long attrs) { unsigned long flags; int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; @@ -561,6 +565,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, * First, sync the memory before unmapping the entry */ if (orig_addr != INVALID_PHYS_ADDR && + !(attrs & DMA_ATTR_SKIP_CPU_SYNC) && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))) swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE); @@ -654,7 +659,8 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size, * GFP_DMA memory; fall back on map_single(), which * will grab memory from the lowest available address range. */ - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE); + phys_addr_t paddr = map_single(hwdev, 0, size, + DMA_FROM_DEVICE, 0); if (paddr == SWIOTLB_MAP_ERROR) goto err_warn; @@ -667,9 +673,13 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size, (unsigned long long)dma_mask, (unsigned long long)dev_addr); - /* DMA_TO_DEVICE to avoid memcpy in unmap_single */ + /* + * DMA_TO_DEVICE to avoid memcpy in unmap_single. + * The DMA_ATTR_SKIP_CPU_SYNC is optional. + */ swiotlb_tbl_unmap_single(hwdev, paddr, - size, DMA_TO_DEVICE); + size, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); goto err_warn; } } @@ -698,8 +708,12 @@ swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, if (!is_swiotlb_buffer(paddr)) free_pages((unsigned long)vaddr, get_order(size)); else - /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */ - swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE); + /* + * DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single. + * DMA_ATTR_SKIP_CPU_SYNC is optional. + */ + swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); } EXPORT_SYMBOL(swiotlb_free_coherent); @@ -755,7 +769,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); /* Oh well, have to allocate and map a bounce buffer. */ - map = map_single(dev, phys, size, dir); + map = map_single(dev, phys, size, dir, attrs); if (map == SWIOTLB_MAP_ERROR) { swiotlb_full(dev, size, dir, 1); return phys_to_dma(dev, io_tlb_overflow_buffer); @@ -764,12 +778,13 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, dev_addr = phys_to_dma(dev, map); /* Ensure that the address returned is DMA'ble */ - if (!dma_capable(dev, dev_addr, size)) { - swiotlb_tbl_unmap_single(dev, map, size, dir); - return phys_to_dma(dev, io_tlb_overflow_buffer); - } + if (dma_capable(dev, dev_addr, size)) + return dev_addr; + + swiotlb_tbl_unmap_single(dev, map, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); - return dev_addr; + return phys_to_dma(dev, io_tlb_overflow_buffer); } EXPORT_SYMBOL_GPL(swiotlb_map_page); @@ -782,14 +797,15 @@ EXPORT_SYMBOL_GPL(swiotlb_map_page); * whatever the device wrote there. */ static void unmap_single(struct device *hwdev, dma_addr_t dev_addr, - size_t size, enum dma_data_direction dir) + size_t size, enum dma_data_direction dir, + unsigned long attrs) { phys_addr_t paddr = dma_to_phys(hwdev, dev_addr); BUG_ON(dir == DMA_NONE); if (is_swiotlb_buffer(paddr)) { - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); return; } @@ -809,7 +825,7 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, size_t size, enum dma_data_direction dir, unsigned long attrs) { - unmap_single(hwdev, dev_addr, size, dir); + unmap_single(hwdev, dev_addr, size, dir, attrs); } EXPORT_SYMBOL_GPL(swiotlb_unmap_page); @@ -891,7 +907,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems, if (swiotlb_force || !dma_capable(hwdev, dev_addr, sg->length)) { phys_addr_t map = map_single(hwdev, sg_phys(sg), - sg->length, dir); + sg->length, dir, attrs); if (map == SWIOTLB_MAP_ERROR) { /* Don't panic here, we expect map_sg users to do proper error handling. */ @@ -925,7 +941,8 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, BUG_ON(dir == DMA_NONE); for_each_sg(sgl, sg, nelems, i) - unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir); + unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, + attrs); } EXPORT_SYMBOL(swiotlb_unmap_sg_attrs); -- cgit v1.2.3 From d29fa0cb7602fa3e96c9eee05e14d14d3e823c89 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Thu, 10 Nov 2016 07:05:31 -0500 Subject: swiotlb: Minor fix-ups for DMA_ATTR_SKIP_CPU_SYNC support I am updating the paths so that instead of trying to pass "attr | DMA_ATTR_SKIP_CPU_SYNC" we instead just OR the value into attr and then pass it since attr will not be used after we make the unmap call. I realized there was one spot I had missed when I was applying the DMA attribute to the DMA mapping exception handling. This change corrects that. Finally it looks like there is a stray blank line at the end of the swiotlb_unmap_sg_attrs function that can be dropped. Signed-off-by: Alexander Duyck Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/swiotlb-xen.c | 4 ++-- lib/swiotlb.c | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/xen') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 3d048afcee38..478fb91e3df2 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -420,8 +420,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, if (dma_capable(dev, dev_addr, size)) return dev_addr; - swiotlb_tbl_unmap_single(dev, map, size, dir, - attrs | DMA_ATTR_SKIP_CPU_SYNC); + attrs |= DMA_ATTR_SKIP_CPU_SYNC; + swiotlb_tbl_unmap_single(dev, map, size, dir, attrs); return DMA_ERROR_CODE; } diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 8e883c762728..cb1b54ee8527 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -781,8 +781,8 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, if (dma_capable(dev, dev_addr, size)) return dev_addr; - swiotlb_tbl_unmap_single(dev, map, size, dir, - attrs | DMA_ATTR_SKIP_CPU_SYNC); + attrs |= DMA_ATTR_SKIP_CPU_SYNC; + swiotlb_tbl_unmap_single(dev, map, size, dir, attrs); return phys_to_dma(dev, io_tlb_overflow_buffer); } @@ -912,6 +912,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems, /* Don't panic here, we expect map_sg users to do proper error handling. */ swiotlb_full(hwdev, sg->length, dir, 0); + attrs |= DMA_ATTR_SKIP_CPU_SYNC; swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, attrs); sg_dma_len(sgl) = 0; @@ -943,7 +944,6 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, for_each_sg(sgl, sg, nelems, i) unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, attrs); - } EXPORT_SYMBOL(swiotlb_unmap_sg_attrs); -- cgit v1.2.3