drm/vc4: Revert "drm/vc4: Evict user mappings of shaders while they're being executed."

This reverts commit cd95e2a4feb4cf7a5e47da3e320f9fc3336899e4.

This appears to be broken on 3.18 on rpi2, and I haven't figured out
why yet.  It causes a system lockup with sometimes an angry RCU
complaint beforehand.

5 files changed, 3 insertions, 118 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index 0cdfdd98b5e5..c39413f6bcbc 100644
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -254,113 +254,6 @@ vc4_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags)
 	return drm_gem_prime_export(dev, obj, flags);
 }
 
-
-/* vc4_gem_fault - fault handler for user mappings of objects.
- *
- * We don't just use the GEM helpers because we have to make sure that
- * the user can't touch shader contents while they're being executed.
- */
-static int
-vc4_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
-	struct drm_gem_object *gem_bo = vma->vm_private_data;
-	struct vc4_bo *bo = to_vc4_bo(gem_bo);
-	struct drm_device *dev = gem_bo->dev;
-	pgoff_t page_offset;
-	unsigned long pfn;
-	int ret = 0;
-
-	/* We don't use vmf->pgoff since that has the fake offset */
-	page_offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >>
-		PAGE_SHIFT;
-
-	ret = mutex_lock_interruptible(&dev->struct_mutex);
-	if (ret)
-		goto out;
-
-	if (bo->validated_shader) {
-		ret = vc4_wait_for_seqno(dev, bo->seqno, ~0ull);
-		if (ret)
-			goto unlock;
-
-		kfree(bo->validated_shader);
-		bo->validated_shader = NULL;
-	}
-
-	pfn = (bo->base.paddr >> PAGE_SHIFT) + page_offset;
-
-	ret = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address, pfn);
-unlock:
-	mutex_unlock(&dev->struct_mutex);
-out:
-	switch (ret) {
-	case 0:
-	case -ERESTARTSYS:
-	case -EINTR:
-	case -EBUSY:
-		ret = VM_FAULT_NOPAGE;
-		break;
-	case -ENOMEM:
-		ret = VM_FAULT_OOM;
-		break;
-	case -ENOSPC:
-	case -EFAULT:
-		ret = VM_FAULT_SIGBUS;
-		break;
-	default:
-		WARN_ONCE(ret, "unhandled error in vc4_gem_fault: %i\n", ret);
-		ret = VM_FAULT_SIGBUS;
-		break;
-	}
-
-	return ret;
-}
-
-const struct vm_operations_struct vc4_vm_ops = {
-	.fault = vc4_gem_fault,
-	.open = drm_gem_vm_open,
-	.close = drm_gem_vm_close,
-};
-
-int
-vc4_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	int ret;
-
-	ret = drm_gem_mmap(filp, vma);
-	if (ret)
-		return ret;
-
-	/* Since our objects all come from normal system memory, clear
-	 * PFNMAP that was defaulted by drm_gem_mmap_obj() to indicate
-	 * that they have a "struct page" managing them.
-	 */
-	vma->vm_flags &= ~VM_PFNMAP;
-
-	/* Not sure why we need to do this. */
-	vma->vm_flags |= VM_MIXEDMAP;
-
-	/* We only do whole-object mappings. */
-	vma->vm_pgoff = 0;
-
-	return 0;
-}
-
-/* Removes all user mappings of the object.
- *
- * This is used to ensure that the user can't modify shaders while the
- * GPU is executing them.  If the user tries to access these unmapped
- * pages, they'll hit a pagefault and end up in vc4_gem_fault(), which
- * then can wait for execution to finish.
- */
-void
-vc4_force_user_unmap(struct drm_gem_object *gem_obj)
-{
-	struct drm_device *dev = gem_obj->dev;
-
-	drm_vma_node_unmap(&gem_obj->vma_node, dev->anon_inode->i_mapping);
-}
-
 int
 vc4_create_bo_ioctl(struct drm_device *dev, void *data,
 		    struct drm_file *file_priv)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 9fbd3b949479..a0fdd1a0d387 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -100,7 +100,7 @@ static const struct file_operations vc4_drm_fops = {
 	.open = drm_open,
 	.release = drm_release,
 	.unlocked_ioctl = drm_ioctl,
-	.mmap = vc4_mmap,
+	.mmap = drm_gem_cma_mmap,
 	.poll = drm_poll,
 	.read = drm_read,
 #ifdef CONFIG_COMPAT
@@ -117,7 +117,6 @@ static const struct drm_ioctl_desc vc4_drm_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(VC4_MMAP_BO, vc4_mmap_bo_ioctl, 0),
 };
 
-
 static struct drm_driver vc4_drm_driver = {
 	.driver_features = (DRIVER_MODESET |
 			    DRIVER_GEM |
@@ -142,7 +141,7 @@ static struct drm_driver vc4_drm_driver = {
 #endif
 
 	.gem_free_object = vc4_free_object,
-	.gem_vm_ops = &vc4_vm_ops,
+	.gem_vm_ops = &drm_gem_cma_vm_ops,
 
 	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 3226ef432e32..28f9f58c4dd9 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -352,7 +352,6 @@ void vc4_disable_vblank(struct drm_device *dev, int crtc_id);
 #define wait_for(COND, MS) _wait_for(COND, MS, 1)
 
 /* vc4_bo.c */
-extern const struct vm_operations_struct vc4_vm_ops;
 void vc4_bo_cache_init(struct drm_device *dev);
 void vc4_free_object(struct drm_gem_object *gem_obj);
 struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t size);
@@ -363,8 +362,6 @@ struct drm_gem_object *vc4_prime_import(struct drm_device *dev,
 					struct dma_buf *dma_buf);
 struct dma_buf *vc4_prime_export(struct drm_device *dev,
 				 struct drm_gem_object *obj, int flags);
-int vc4_mmap(struct file *filp, struct vm_area_struct *vma);
-void vc4_force_user_unmap(struct drm_gem_object *gem_obj);
 int vc4_create_bo_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
 int vc4_mmap_bo_ioctl(struct drm_device *dev, void *data,
@@ -386,8 +383,6 @@ int vc4_wait_seqno_ioctl(struct drm_device *dev, void *data,
 int vc4_wait_bo_ioctl(struct drm_device *dev, void *data,
 		      struct drm_file *file_priv);
 void vc4_submit_next_job(struct drm_device *dev);
-int vc4_wait_for_seqno(struct drm_device *dev, uint64_t seqno,
-		       uint64_t timeout_ns);
 
 /* vc4_hdmi.c */
 void vc4_hdmi_register(void);
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 34036c3f0f50..8843c4cf9948 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -117,7 +117,7 @@ submit_cl(struct drm_device *dev, uint32_t thread, uint32_t start, uint32_t end)
 	barrier();
 }
 
-int
+static int
 vc4_wait_for_seqno(struct drm_device *dev, uint64_t seqno, uint64_t timeout_ns)
 {
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
diff --git a/drivers/gpu/drm/vc4/vc4_validate_shaders.c b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
index 2b4a4ec64f7a..839d5521cfe5 100644
--- a/drivers/gpu/drm/vc4/vc4_validate_shaders.c
+++ b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
@@ -382,8 +382,6 @@ vc4_validate_shader(struct drm_gem_cma_object *shader_obj)
 	if (shader_bo->validated_shader)
 		return shader_bo->validated_shader;
 
-	vc4_force_user_unmap(&shader_obj->base);
-
 	/* Our validation relies on nothing modifying the shader
 	 * contents after us, so just ban sending us busy BOs.
 	 */