diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index b9a772b26fa1..ad95e8b9852b 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -381,6 +381,33 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo, return (!map->virtual) ? -ENOMEM : 0; } +/** + * + * ttm_bo_kmap_try_from_panic + * + * @bo: The buffer object + * @page: The page to map + * + * Sets up a kernel virtual mapping using kmap_local_page_try_from_panic(). + * This should only be called from the panic handler, if you make sure the bo + * is the one being displayed, so is properly allocated, and protected. + * + * Returns the vaddr, that you can use to write to the bo, and that you should + * pass to kunmap_local() when you're done with this page, or NULL if the bo + * is in iomem. + */ +void *ttm_bo_kmap_try_from_panic(struct ttm_buffer_object *bo, unsigned long page) +{ + if (page + 1 > PFN_UP(bo->resource->size)) + return NULL; + + if (!bo->resource->bus.is_iomem && bo->ttm->pages && bo->ttm->pages[page]) + return kmap_local_page_try_from_panic(bo->ttm->pages[page]); + + return NULL; +} +EXPORT_SYMBOL(ttm_bo_kmap_try_from_panic); + /** * ttm_bo_kmap * diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h index 8ad6e2713625..5332ee74d95b 100644 --- a/include/drm/ttm/ttm_bo.h +++ b/include/drm/ttm/ttm_bo.h @@ -401,6 +401,7 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo, int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page, unsigned long num_pages, struct ttm_bo_kmap_obj *map); void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map); +void *ttm_bo_kmap_try_from_panic(struct ttm_buffer_object *bo, unsigned long page); int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map); void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct iosys_map *map); int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo);