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| author | Jocelyn Falempe <jfalempe@redhat.com> | 2025-06-24 11:01:14 +0200 |
|---|---|---|
| committer | Maarten Lankhorst <dev@lankhorst.se> | 2025-06-27 11:48:22 +0200 |
| commit | 718370ff283284f191155a5eb9d4f376aaf93bb8 (patch) | |
| tree | 8ec303218effc21b9c097bfaa0378172c10448c5 | |
| parent | drm/i915/display: Add a disable_tiling() for skl planes (diff) | |
| download | linux-718370ff283284f191155a5eb9d4f376aaf93bb8.tar.gz linux-718370ff283284f191155a5eb9d4f376aaf93bb8.zip | |
drm/ttm: Add ttm_bo_kmap_try_from_panic()
If the ttm bo is backed by pages, then it's possible to safely kmap
one page at a time, using kmap_try_from_panic().
Unfortunately there is no way to do the same with ioremap, so it
only supports the kmap case.
This is needed for proper drm_panic support with xe driver.
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20250624091501.257661-6-jfalempe@redhat.com
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo_util.c | 27 | ||||
| -rw-r--r-- | include/drm/ttm/ttm_bo.h | 1 |
2 files changed, 28 insertions, 0 deletions
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 @@ -382,6 +382,33 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo, } /** + * + * 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 * * @bo: The buffer object. 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); |