72 lines
2.4 KiB
Diff
72 lines
2.4 KiB
Diff
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From 2c7e4a1ac8ec1f908927793e893566aac3dcb9df Mon Sep 17 00:00:00 2001
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From: Merlijn Wajer <merlijn@wizzup.org>
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Date: Sun, 12 Dec 2021 02:23:36 +0100
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Subject: [PATCH] wip: Revert "dma-direct: Fix potential NULL pointer
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dereference"
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This reverts commit f959dcd6ddfd29235030e8026471ac1b022ad2b0.
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We will need to find a proper fix for this - but it looks like the
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dma_capable change in include/linux/dma-direct.h makes the ssi code
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always take the DMA path, which causes various problems. I am not 100%
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sure that is case, but I have a hunch that pio was always used on the
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N900 for this. If this is not the case, we'll have figure out what else
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is required to make DMA work again.
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---
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include/linux/dma-direct.h | 4 ++++
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kernel/dma/mapping.c | 9 ---------
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2 files changed, 4 insertions(+), 9 deletions(-)
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diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
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index 18aade195884..6eb8f8ae76da 100644
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--- a/include/linux/dma-direct.h
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+++ b/include/linux/dma-direct.h
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@@ -103,6 +103,10 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
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if (addr == DMA_MAPPING_ERROR)
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return false;
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+
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+ if (!dev->dma_mask)
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+ return false;
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+
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if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
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min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
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return false;
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diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
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index 8349a9f2c345..899e6fbb9f40 100644
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--- a/kernel/dma/mapping.c
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+++ b/kernel/dma/mapping.c
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@@ -148,9 +148,6 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
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BUG_ON(!valid_dma_direction(dir));
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- if (WARN_ON_ONCE(!dev->dma_mask))
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- return DMA_MAPPING_ERROR;
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-
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if (dma_map_direct(dev, ops) ||
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arch_dma_map_page_direct(dev, page_to_phys(page) + offset + size))
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addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
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@@ -185,9 +182,6 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
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BUG_ON(!valid_dma_direction(dir));
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- if (WARN_ON_ONCE(!dev->dma_mask))
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- return 0;
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-
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if (dma_map_direct(dev, ops) ||
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arch_dma_map_sg_direct(dev, sg, nents))
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ents = dma_direct_map_sg(dev, sg, nents, dir, attrs);
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@@ -293,9 +287,6 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
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BUG_ON(!valid_dma_direction(dir));
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- if (WARN_ON_ONCE(!dev->dma_mask))
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- return DMA_MAPPING_ERROR;
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-
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/* Don't allow RAM to be mapped */
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if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
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return DMA_MAPPING_ERROR;
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--
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2.34.1
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