drm/panfrost: Add BO labelling to Panfrost

Functions for labelling UM-exposed an internal BOs are provided. An
example of the latter would be the Perfcnt sample buffer.

This commit is done in preparation of a following one that will allow
UM to set BO labels through a new ioctl().

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250520174634.353267-2-adrian.larumbe@collabora.com

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 963f04ba2de6547b4b01beee93edc45d0fb83653..4c5be7ccc9ccdaaae9d3308620a8f9875effcab0 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
 
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/dma-buf.h>
@@ -35,6 +36,9 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj)
         */
        WARN_ON_ONCE(!list_empty(&bo->mappings.list));
 
+       kfree_const(bo->label.str);
+       mutex_destroy(&bo->label.lock);
+
        if (bo->sgts) {
                int i;
                int n_sgt = bo->base.base.size / SZ_2M;
@@ -260,6 +264,7 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t
        mutex_init(&obj->mappings.lock);
        obj->base.base.funcs = &panfrost_gem_funcs;
        obj->base.map_wc = !pfdev->coherent;
+       mutex_init(&obj->label.lock);
 
        return &obj->base.base;
 }
@@ -302,3 +307,40 @@ panfrost_gem_prime_import_sg_table(struct drm_device *dev,
 
        return obj;
 }
+
+void
+panfrost_gem_set_label(struct drm_gem_object *obj, const char *label)
+{
+       struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+       const char *old_label;
+
+       scoped_guard(mutex, &bo->label.lock) {
+               old_label = bo->label.str;
+               bo->label.str = label;
+       }
+
+       kfree_const(old_label);
+}
+
+void
+panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label)
+{
+       struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+       const char *str;
+
+       /* We should never attempt labelling a UM-exposed GEM object */
+       if (drm_WARN_ON(bo->base.base.dev, bo->base.base.handle_count > 0))
+               return;
+
+       if (!label)
+               return;
+
+       str = kstrdup_const(label, GFP_KERNEL);
+       if (!str) {
+               /* Failing to allocate memory for a label isn't a fatal condition */
+               drm_warn(bo->base.base.dev, "Not enough memory to allocate BO label");
+               return;
+       }
+
+       panfrost_gem_set_label(obj, str);
+}

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
index 7516b7ecf7feab416491a0cdeba01ceaded16c54..6c187b9b66fcfda84c2dd6274e4136fed68fb5bf 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
@@ -41,6 +41,20 @@ struct panfrost_gem_object {
         */
        size_t heap_rss_size;
 
+       /**
+        * @label: BO tagging fields. The label can be assigned within the
+        * driver itself or through a specific IOCTL.
+        */
+       struct {
+               /**
+                * @label.str: Pointer to NULL-terminated string,
+                */
+               const char *str;
+
+               /** @lock.str: Protects access to the @label.str field. */
+               struct mutex lock;
+       } label;
+
        bool noexec             :1;
        bool is_heap            :1;
 };
@@ -89,4 +103,7 @@ void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo);
 int panfrost_gem_shrinker_init(struct drm_device *dev);
 void panfrost_gem_shrinker_cleanup(struct drm_device *dev);
 
+void panfrost_gem_set_label(struct drm_gem_object *obj, const char *label);
+void panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label);
+
 #endif /* __PANFROST_GEM_H__ */