Merge tag 'dmaengine-fix-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul...

[linux.git] / drivers / gpu / drm / amd / amdgpu / amdgpu_gem.c

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index d0d9bc445d7bc8e7c712f27df880d0149102b183..854fc497844b88fbc4c34321fcf7536364f79a4b 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -255,6 +255,15 @@ static int amdgpu_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_str
        if (bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)
                return -EPERM;
 
+       /* Workaround for Thunk bug creating PROT_NONE,MAP_PRIVATE mappings
+        * for debugger access to invisible VRAM. Should have used MAP_SHARED
+        * instead. Clearing VM_MAYWRITE prevents the mapping from ever
+        * becoming writable and makes is_cow_mapping(vm_flags) false.
+        */
+       if (is_cow_mapping(vma->vm_flags) &&
+           !(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
+               vma->vm_flags &= ~VM_MAYWRITE;
+
        return drm_gem_ttm_mmap(obj, vma);
 }