* [PATCH] dma-mapping: do not mapping module memory
@ 2019-11-29 11:03 lijiazi
2019-12-02 7:22 ` Christoph Hellwig
0 siblings, 1 reply; 2+ messages in thread
From: lijiazi @ 2019-11-29 11:03 UTC (permalink / raw)
To: Christoph Hellwig, Marek Szyprowski, Robin Murphy, Andrew Morton
Cc: lijiazi, iommu, linux-mm
On ARM, x86_64, sparc64 platform, virt_to_page only convert a
_valid_ virtual address to struct page *, virt_addr_valid(x)
indicates whether a virtual address is valid. If ptr is point
to a static variable in module area, virt_to_page will return
a invalid value.
Signed-off-by: lijiazi <lijiazi@xiaomi.com>
---
include/linux/dma-mapping.h | 10 +++++++---
mm/vmalloc.c | 1 +
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 330ad58..37e645d 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -580,9 +580,13 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev)
static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
- /* DMA must never operate on areas that might be remapped. */
- if (dev_WARN_ONCE(dev, is_vmalloc_addr(ptr),
- "rejecting DMA map of vmalloc memory\n"))
+ /* DMA must never operate on areas that might be remapped.
+ * ARM, X86_64, sparc64 put module in a special place, if ptr
+ * point to static variable in module area, virt_to_page will
+ * return err page *.
+ */
+ if (dev_WARN_ONCE(dev, is_vmalloc_or_module_addr(ptr),
+ "rejecting DMA map of vmalloc or module memory\n"))
return DMA_MAPPING_ERROR;
debug_dma_map_single(dev, ptr, size);
return dma_map_page_attrs(dev, virt_to_page(ptr), offset_in_page(ptr),
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 588303a..71ce6dc 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -262,6 +262,7 @@ int is_vmalloc_or_module_addr(const void *x)
#endif
return is_vmalloc_addr(x);
}
+EXPORT_SYMBOL(is_vmalloc_or_module_addr);
/*
* Walk a vmap address to the struct page it maps.
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] dma-mapping: do not mapping module memory
2019-11-29 11:03 [PATCH] dma-mapping: do not mapping module memory lijiazi
@ 2019-12-02 7:22 ` Christoph Hellwig
0 siblings, 0 replies; 2+ messages in thread
From: Christoph Hellwig @ 2019-12-02 7:22 UTC (permalink / raw)
To: lijiazi
Cc: Christoph Hellwig, Marek Szyprowski, Robin Murphy, Andrew Morton,
lijiazi, iommu, linux-mm
On Fri, Nov 29, 2019 at 07:03:40PM +0800, lijiazi wrote:
> On ARM, x86_64, sparc64 platform, virt_to_page only convert a
> _valid_ virtual address to struct page *, virt_addr_valid(x)
> indicates whether a virtual address is valid. If ptr is point
> to a static variable in module area, virt_to_page will return
> a invalid value.
While the path isn't wrong, why bother?
^ permalink raw reply [flat|nested] 2+ messages in thread
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2019-12-02 7:22 ` Christoph Hellwig
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