From 91ef26f914171cf753330f13724fd9142b5b1640 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 3 Feb 2020 18:11:10 +0100 Subject: dma-direct: relax addressability checks in dma_direct_supported dma_direct_supported tries to find the minimum addressable bitmask based on the end pfn and optional magic that architectures can use to communicate the size of the magic ZONE_DMA that can be used for bounce buffering. But between the DMA offsets that can change per device (or sometimes even region), the fact the ZONE_DMA isn't even guaranteed to be the lowest addresses and failure of having proper interfaces to the MM code this fails at least for one arm subarchitecture. As all the legacy DMA implementations have supported 32-bit DMA masks, and 32-bit masks are guranteed to always work by the API contract (using bounce buffers if needed), we can short cut the complicated check and always return true without breaking existing assumptions. Hopefully we can properly clean up the interaction with the arch defined zones and the bootmem allocator eventually. Fixes: ad3c7b18c5b3 ("arm: use swiotlb for bounce buffering on LPAE configs") Reported-by: Peter Ujfalusi Signed-off-by: Christoph Hellwig Tested-by: Peter Ujfalusi --- kernel/dma/direct.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) (limited to 'kernel/dma/direct.c') diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 6af7ae83c4ad..32ec69cdba54 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -472,28 +472,26 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma, } #endif /* CONFIG_MMU */ -/* - * Because 32-bit DMA masks are so common we expect every architecture to be - * able to satisfy them - either by not supporting more physical memory, or by - * providing a ZONE_DMA32. If neither is the case, the architecture needs to - * use an IOMMU instead of the direct mapping. - */ int dma_direct_supported(struct device *dev, u64 mask) { - u64 min_mask; - - if (IS_ENABLED(CONFIG_ZONE_DMA)) - min_mask = DMA_BIT_MASK(zone_dma_bits); - else - min_mask = DMA_BIT_MASK(32); + u64 min_mask = (max_pfn - 1) << PAGE_SHIFT; - min_mask = min_t(u64, min_mask, (max_pfn - 1) << PAGE_SHIFT); + /* + * Because 32-bit DMA masks are so common we expect every architecture + * to be able to satisfy them - either by not supporting more physical + * memory, or by providing a ZONE_DMA32. If neither is the case, the + * architecture needs to use an IOMMU instead of the direct mapping. + */ + if (mask >= DMA_BIT_MASK(32)) + return 1; /* * This check needs to be against the actual bit mask value, so * use __phys_to_dma() here so that the SME encryption mask isn't * part of the check. */ + if (IS_ENABLED(CONFIG_ZONE_DMA)) + min_mask = min_t(u64, min_mask, DMA_BIT_MASK(zone_dma_bits)); return mask >= __phys_to_dma(dev, min_mask); } -- cgit v1.2.3 From 4a47cbae04844f0c5e2365aa6c217b61850bb832 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 3 Feb 2020 14:44:38 +0100 Subject: dma-direct: improve swiotlb error reporting Untangle the way how dma_direct_map_page calls into swiotlb to be able to properly report errors where the swiotlb DMA address overflows the mask separately from overflows in the !swiotlb case. This means that siotlb_map now has to do a little more work that duplicates dma_direct_map_page, but doing so greatly simplifies the calling convention. Signed-off-by: Christoph Hellwig Reviewed-by: Konrad Rzeszutek Wilk --- include/linux/swiotlb.h | 11 +++-------- kernel/dma/direct.c | 16 +++++++--------- kernel/dma/swiotlb.c | 42 +++++++++++++++++++++++------------------- 3 files changed, 33 insertions(+), 36 deletions(-) (limited to 'kernel/dma/direct.c') diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index cde3dc18e21a..046bb94bd4d6 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -64,6 +64,9 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev, size_t size, enum dma_data_direction dir, enum dma_sync_target target); +dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys, + size_t size, enum dma_data_direction dir, unsigned long attrs); + #ifdef CONFIG_SWIOTLB extern enum swiotlb_force swiotlb_force; extern phys_addr_t io_tlb_start, io_tlb_end; @@ -73,8 +76,6 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr) return paddr >= io_tlb_start && paddr < io_tlb_end; } -bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, - size_t size, enum dma_data_direction dir, unsigned long attrs); void __init swiotlb_exit(void); unsigned int swiotlb_max_segment(void); size_t swiotlb_max_mapping_size(struct device *dev); @@ -85,12 +86,6 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr) { return false; } -static inline bool swiotlb_map(struct device *dev, phys_addr_t *phys, - dma_addr_t *dma_addr, size_t size, enum dma_data_direction dir, - unsigned long attrs) -{ - return false; -} static inline void swiotlb_exit(void) { } diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 32ec69cdba54..594bddd04e01 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -357,13 +357,6 @@ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl, EXPORT_SYMBOL(dma_direct_unmap_sg); #endif -static inline bool dma_direct_possible(struct device *dev, dma_addr_t dma_addr, - size_t size) -{ - return swiotlb_force != SWIOTLB_FORCE && - dma_capable(dev, dma_addr, size, true); -} - dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, unsigned long attrs) @@ -371,8 +364,13 @@ dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys); - if (unlikely(!dma_direct_possible(dev, dma_addr, size)) && - !swiotlb_map(dev, &phys, &dma_addr, size, dir, attrs)) { + if (unlikely(swiotlb_force == SWIOTLB_FORCE)) + return swiotlb_map(dev, phys, size, dir, attrs); + + if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + if (swiotlb_force != SWIOTLB_NO_FORCE) + return swiotlb_map(dev, phys, size, dir, attrs); + report_addr(dev, dma_addr, size); return DMA_MAPPING_ERROR; } diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 9280d6f8271e..c19379fabd20 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -22,6 +22,7 @@ #include #include +#include #include #include #include @@ -656,35 +657,38 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, } /* - * Create a swiotlb mapping for the buffer at @phys, and in case of DMAing + * Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing * to the device copy the data into it as well. */ -bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, - size_t size, enum dma_data_direction dir, unsigned long attrs) +dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size, + enum dma_data_direction dir, unsigned long attrs) { - trace_swiotlb_bounced(dev, *dma_addr, size, swiotlb_force); + phys_addr_t swiotlb_addr; + dma_addr_t dma_addr; - if (unlikely(swiotlb_force == SWIOTLB_NO_FORCE)) { - dev_warn_ratelimited(dev, - "Cannot do DMA to address %pa\n", phys); - return false; - } + trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size, + swiotlb_force); - /* Oh well, have to allocate and map a bounce buffer. */ - *phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start), - *phys, size, size, dir, attrs); - if (*phys == (phys_addr_t)DMA_MAPPING_ERROR) - return false; + swiotlb_addr = swiotlb_tbl_map_single(dev, + __phys_to_dma(dev, io_tlb_start), + paddr, size, size, dir, attrs); + if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR) + return DMA_MAPPING_ERROR; /* Ensure that the address returned is DMA'ble */ - *dma_addr = __phys_to_dma(dev, *phys); - if (unlikely(!dma_capable(dev, *dma_addr, size, true))) { - swiotlb_tbl_unmap_single(dev, *phys, size, size, dir, + dma_addr = __phys_to_dma(dev, swiotlb_addr); + if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, size, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC); - return false; + dev_WARN_ONCE(dev, 1, + "swiotlb addr %pad+%zu overflow (mask %llx, bus limit %llx).\n", + &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); + return DMA_MAPPING_ERROR; } - return true; + if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + arch_sync_dma_for_device(swiotlb_addr, size, dir); + return dma_addr; } size_t swiotlb_max_mapping_size(struct device *dev) -- cgit v1.2.3 From 75467ee48a5e04cf3ae3cb39aea6adee73aeff91 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 3 Feb 2020 14:54:50 +0100 Subject: dma-direct: improve DMA mask overflow reporting Remove the unset dma_mask case as that won't get into mapping calls anymore, and also report the other errors unconditonally and with a slightly improved message. Remove the now pointless report_addr helper. Signed-off-by: Christoph Hellwig Reviewed-by: Konrad Rzeszutek Wilk --- kernel/dma/direct.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) (limited to 'kernel/dma/direct.c') diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 594bddd04e01..ac7956c38f69 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -23,18 +23,6 @@ */ unsigned int zone_dma_bits __ro_after_init = 24; -static void report_addr(struct device *dev, dma_addr_t dma_addr, size_t size) -{ - if (!dev->dma_mask) { - dev_err_once(dev, "DMA map on device without dma_mask\n"); - } else if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_limit) { - dev_err_once(dev, - "overflow %pad+%zu of DMA mask %llx bus limit %llx\n", - &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); - } - WARN_ON_ONCE(1); -} - static inline dma_addr_t phys_to_dma_direct(struct device *dev, phys_addr_t phys) { @@ -371,7 +359,9 @@ dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, if (swiotlb_force != SWIOTLB_NO_FORCE) return swiotlb_map(dev, phys, size, dir, attrs); - report_addr(dev, dma_addr, size); + dev_WARN_ONCE(dev, 1, + "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n", + &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); return DMA_MAPPING_ERROR; } @@ -409,7 +399,10 @@ dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr, dma_addr_t dma_addr = paddr; if (unlikely(!dma_capable(dev, dma_addr, size, false))) { - report_addr(dev, dma_addr, size); + dev_err_once(dev, + "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n", + &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); + WARN_ON_ONCE(1); return DMA_MAPPING_ERROR; } -- cgit v1.2.3