From 2a29e9f6b9b499f1fc5f4a48220dc3f4428499f9 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 3 Apr 2019 21:34:34 +0200 Subject: [PATCH 1/2] sparc64/pci_sun4v: fix ATU checks for large DMA masks Now that we allow drivers to always need to set larger than required DMA masks we need to be a little more careful in the sun4v PCI iommu driver to chose when to select the ATU support - a larger DMA mask can be set even when the platform does not support ATU, so we always have to check if it is avaiable before using it. Add a little helper for that and use it in all the places where we make ATU usage decisions based on the DMA mask. Fixes: 24132a419c68 ("sparc64/pci_sun4v: allow large DMA masks") Reported-by: Meelis Roos Signed-off-by: Christoph Hellwig Tested-by: Meelis Roos Acked-by: David S. Miller --- arch/sparc/kernel/pci_sun4v.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c index a8af6023c126..14b93c5564e3 100644 --- a/arch/sparc/kernel/pci_sun4v.c +++ b/arch/sparc/kernel/pci_sun4v.c @@ -73,6 +73,11 @@ static inline void iommu_batch_start(struct device *dev, unsigned long prot, uns p->npages = 0; } +static inline bool iommu_use_atu(struct iommu *iommu, u64 mask) +{ + return iommu->atu && mask > DMA_BIT_MASK(32); +} + /* Interrupts must be disabled. */ static long iommu_batch_flush(struct iommu_batch *p, u64 mask) { @@ -92,7 +97,7 @@ static long iommu_batch_flush(struct iommu_batch *p, u64 mask) prot &= (HV_PCI_MAP_ATTR_READ | HV_PCI_MAP_ATTR_WRITE); while (npages != 0) { - if (mask <= DMA_BIT_MASK(32) || !pbm->iommu->atu) { + if (!iommu_use_atu(pbm->iommu, mask)) { num = pci_sun4v_iommu_map(devhandle, HV_PCI_TSBID(0, entry), npages, @@ -179,7 +184,6 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size, unsigned long flags, order, first_page, npages, n; unsigned long prot = 0; struct iommu *iommu; - struct atu *atu; struct iommu_map_table *tbl; struct page *page; void *ret; @@ -205,13 +209,11 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size, memset((char *)first_page, 0, PAGE_SIZE << order); iommu = dev->archdata.iommu; - atu = iommu->atu; - mask = dev->coherent_dma_mask; - if (mask <= DMA_BIT_MASK(32) || !atu) + if (!iommu_use_atu(iommu, mask)) tbl = &iommu->tbl; else - tbl = &atu->tbl; + tbl = &iommu->atu->tbl; entry = iommu_tbl_range_alloc(dev, tbl, npages, NULL, (unsigned long)(-1), 0); @@ -333,7 +335,7 @@ static void dma_4v_free_coherent(struct device *dev, size_t size, void *cpu, atu = iommu->atu; devhandle = pbm->devhandle; - if (dvma <= DMA_BIT_MASK(32)) { + if (!iommu_use_atu(iommu, dvma)) { tbl = &iommu->tbl; iotsb_num = 0; /* we don't care for legacy iommu */ } else { @@ -374,7 +376,7 @@ static dma_addr_t dma_4v_map_page(struct device *dev, struct page *page, npages >>= IO_PAGE_SHIFT; mask = *dev->dma_mask; - if (mask <= DMA_BIT_MASK(32)) + if (!iommu_use_atu(iommu, mask)) tbl = &iommu->tbl; else tbl = &atu->tbl; @@ -510,7 +512,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist, IO_PAGE_SIZE) >> IO_PAGE_SHIFT; mask = *dev->dma_mask; - if (mask <= DMA_BIT_MASK(32)) + if (!iommu_use_atu(iommu, mask)) tbl = &iommu->tbl; else tbl = &atu->tbl; From 8c5165430c0194df92369162d1c7f53f8672baa5 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Wed, 10 Apr 2019 16:59:25 -0500 Subject: [PATCH 2/2] dma-debug: only skip one stackframe entry With skip set to 1, I get a traceback like this: [ 106.867637] DMA-API: Mapped at: [ 106.870784] afu_dma_map_region+0x2cd/0x4f0 [dfl_afu] [ 106.875839] afu_ioctl+0x258/0x380 [dfl_afu] [ 106.880108] do_vfs_ioctl+0xa9/0x720 [ 106.883688] ksys_ioctl+0x60/0x90 [ 106.887007] __x64_sys_ioctl+0x16/0x20 With the previous value of 2, afu_dma_map_region was being omitted. I suspect that the code paths have simply changed since the value of 2 was chosen a decade ago, but it's also possible that it varies based on which mapping function was used, compiler inlining choices, etc. In any case, it's best to err on the side of skipping less. Signed-off-by: Scott Wood Signed-off-by: Christoph Hellwig --- kernel/dma/debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c index 45d51e8e26f6..a218e43cc382 100644 --- a/kernel/dma/debug.c +++ b/kernel/dma/debug.c @@ -706,7 +706,7 @@ static struct dma_debug_entry *dma_entry_alloc(void) #ifdef CONFIG_STACKTRACE entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES; entry->stacktrace.entries = entry->st_entries; - entry->stacktrace.skip = 2; + entry->stacktrace.skip = 1; save_stack_trace(&entry->stacktrace); #endif