Hi Ørjan, On Thu, Apr 16, 2015 at 10:41 PM, Ørjan Eide <orjan.eide@xxxxxxx> wrote: > arm_iommu_mmap_attrs() ignores the page offset in vma->vm_pgoff that was > specified in the mmap call. Any user of dma_mmap_* will get an > unexpected result when the device uses the IOMMU DMA ops. > > Some DRM driver that use dma_mmap_* seems to depend on it ignoring > vma->vm_pgoff. Both the Samsung Exynos DRM driver before v3.18, and the > current Rockchip DRM driver, use the page offset to pass GEM cookies > that are used to look up the GEM buffers and then call dma_mmap_attrs() > with the cookie value still in vma->vm_pgoff. > > rockchip_gem_mmap_buf() in drivers/gpu/drm/rockchip/rockchip_drm_gem.c > still does this. It should be fixed before fixing > arm_iommu_mmap_attrs(). > > Signed-off-by: Ørjan Eide <orjan.eide@xxxxxxx> Reviewed-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx> I tested this patch on my RK3288 board with the corresponding rockchip_drm patch [0], and it works. So, also: Tested-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx> [0] https://patchwork.kernel.org/patch/6226591/ > --- > arch/arm/mm/dma-mapping.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > index c274476..07d571b 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -1364,6 +1364,9 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, > { > unsigned long uaddr = vma->vm_start; > unsigned long usize = vma->vm_end - vma->vm_start; > + unsigned long nr_vma_pages = usize >> PAGE_SHIFT; > + unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; > + unsigned long off = vma->vm_pgoff; > struct page **pages = __iommu_get_pages(cpu_addr, attrs); > > vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot); > @@ -1371,6 +1374,11 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma, > if (!pages) > return -ENXIO; > > + if (off >= nr_pages || nr_vma_pages > (nr_pages - off)) > + return -ENXIO; > + > + pages += off; > + > do { > int ret = vm_insert_page(vma, uaddr, *pages++); > if (ret) { > -- > 1.9.1 > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
