Marek Szyprowski wrote:
> When IOMMU support was enabled, dma-buf import in Exynos DRM was broken
> since commit f43c35966a5a ("drm/exynos: use real device for DMA-mapping
> operations") due to using wrong struct device in drm_gem_prime_import()
> function. This patch fixes following kernel BUG caused by incorrect buffer
> mapping to DMA address space:
>
> exynos-sysmmu 1465.sysmmu: 1445.mixer: PAGE FAULT occurred at
> 0xb2e0
> [ cut here ]
> kernel BUG at drivers/iommu/exynos-iommu.c:449!
> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted
> 4.14.0-rc4-next-20171016-00033-g990d723669fd #3165
> Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
> task: c0e0b7c0 task.stack: c0e0
> PC is at exynos_sysmmu_irq+0x1d0/0x24c
> LR is at exynos_sysmmu_irq+0x154/0x24c
> [ cut here ]
Reviewed-by: Tobias Jakobi
- Tobias
> Reported-by: Marian Mihailescu
> Fixes: f43c35966a5a ("drm/exynos: use real device for DMA-mapping operations")
> Signed-off-by: Marek Szyprowski
> ---
> drivers/gpu/drm/exynos/exynos_drm_drv.c | 2 +-
> drivers/gpu/drm/exynos/exynos_drm_gem.c | 6 ++
> drivers/gpu/drm/exynos/exynos_drm_gem.h | 2 ++
> 3 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c
> b/drivers/gpu/drm/exynos/exynos_drm_drv.c
> index e651a58c18cf..0822c5341ba4 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
> @@ -148,7 +148,7 @@ static struct drm_driver exynos_drm_driver = {
> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> .gem_prime_export = drm_gem_prime_export,
> - .gem_prime_import = drm_gem_prime_import,
> + .gem_prime_import = exynos_drm_gem_prime_import,
> .gem_prime_get_sg_table = exynos_drm_gem_prime_get_sg_table,
> .gem_prime_import_sg_table = exynos_drm_gem_prime_import_sg_table,
> .gem_prime_vmap = exynos_drm_gem_prime_vmap,
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> index 077de014d610..ef35bc23bb36 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> @@ -506,6 +506,12 @@ int exynos_drm_gem_mmap(struct file *filp, struct
> vm_area_struct *vma)
> }
>
> /* low-level interface prime helpers */
> +struct drm_gem_object *exynos_drm_gem_prime_import(struct drm_device *dev,
> + struct dma_buf *dma_buf)
> +{
> + return drm_gem_prime_import_dev(dev, dma_buf, to_dma_dev(dev));
> +}
> +
> struct sg_table *exynos_drm_gem_prime_get_sg_table(struct drm_gem_object
> *obj)
> {
> struct exynos_drm_gem *exynos_gem = to_exynos_gem(obj);
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h
> b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> index e86d1a9518c3..5a4c7de80f65 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> @@ -117,6 +117,8 @@ int exynos_drm_gem_fault(struct vm_fault *vmf);
> int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
>
> /* low-level interface prime helpers */
> +struct drm_gem_object *exynos_drm_gem_prime_import(struct drm_device *dev,
> + struct dma_buf *dma_buf);
> struct sg_table *exynos_drm_gem_prime_get_sg_table(struct drm_gem_object
> *obj);
> struct drm_gem_object *
> exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
>
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