[PATCH v2 3/4] drm/panthor: show device-wide list of DRM GEM objects over DebugFS
From: Adrián Larumbe
Date: Wed Mar 19 2025 - 11:37:49 EST
Add a device DebugFS file that displays a complete list of all the DRM GEM
objects that are exposed to UM through a DRM handle.
Since leaking object identifiers that might belong to a different NS is
inadmissible, this functionality is only made available in debug builds
with DEBUGFS support enabled.
File format is that of a table, with each entry displaying a variety of
fields with information about each GEM object.
Each GEM object entry in the file displays the following information
fields: Client PID, BO's global name, reference count, BO virtual size, BO
resize size, VM address in its DRM-managed range, BO label and a flag
bitmask.
Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panthor/panthor_device.c | 5 +
drivers/gpu/drm/panthor/panthor_device.h | 11 ++
drivers/gpu/drm/panthor/panthor_drv.c | 26 +++++
drivers/gpu/drm/panthor/panthor_gem.c | 130 +++++++++++++++++++++++
drivers/gpu/drm/panthor/panthor_gem.h | 29 +++++
5 files changed, 201 insertions(+)
diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index a9da1d1eeb70..bae1a74d7111 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -263,6 +263,11 @@ int panthor_device_init(struct panthor_device *ptdev)
pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
pm_runtime_use_autosuspend(ptdev->base.dev);
+#ifdef CONFIG_DEBUG_FS
+ drmm_mutex_init(&ptdev->base, &ptdev->gems.lock);
+ INIT_LIST_HEAD(&ptdev->gems.node);
+#endif
+
ret = drm_dev_register(&ptdev->base, 0);
if (ret)
goto err_disable_autosuspend;
diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index da6574021664..86206a961b38 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -205,6 +205,17 @@ struct panthor_device {
/** @fast_rate: Maximum device clock frequency. Set by DVFS */
unsigned long fast_rate;
+
+#ifdef CONFIG_DEBUG_FS
+ /** @gems: Device-wide list of GEM objects owned by at least one file. */
+ struct {
+ /** @gems.lock: Protects the device-wide list of GEM objects. */
+ struct mutex lock;
+
+ /** @node: Used to keep track of all the device's DRM objects */
+ struct list_head node;
+ } gems;
+#endif
};
struct panthor_gpu_usage {
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index e91acf132e06..61ebf87f2946 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1531,9 +1531,35 @@ static const struct file_operations panthor_drm_driver_fops = {
};
#ifdef CONFIG_DEBUG_FS
+static int panthor_gems_show(struct seq_file *m, void *data)
+{
+ struct drm_info_node *node = m->private;
+ struct drm_device *dev = node->minor->dev;
+ struct panthor_device *ptdev = container_of(dev, struct panthor_device, base);
+
+ panthor_gem_debugfs_print_bos(ptdev, m);
+
+ return 0;
+}
+
+
+static struct drm_info_list panthor_debugfs_list[] = {
+ {"gems", panthor_gems_show, 0, NULL},
+};
+
+static int panthor_gems_debugfs_init(struct drm_minor *minor)
+{
+ drm_debugfs_create_files(panthor_debugfs_list,
+ ARRAY_SIZE(panthor_debugfs_list),
+ minor->debugfs_root, minor);
+
+ return 0;
+}
+
static void panthor_debugfs_init(struct drm_minor *minor)
{
panthor_mmu_debugfs_init(minor);
+ panthor_gems_debugfs_init(minor);
}
#endif
diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c
index 165c7f4eb920..f7eb413d88e7 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.c
+++ b/drivers/gpu/drm/panthor/panthor_gem.c
@@ -2,6 +2,7 @@
/* Copyright 2019 Linaro, Ltd, Rob Herring <robh@xxxxxxxxxx> */
/* Copyright 2023 Collabora ltd. */
+#include <linux/cleanup.h>
#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
@@ -13,11 +14,49 @@
#include "panthor_gem.h"
#include "panthor_mmu.h"
+#ifdef CONFIG_DEBUG_FS
+static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo)
+{
+ INIT_LIST_HEAD(&bo->gems.node);
+ bo->gems.creator.tgid = current->group_leader->pid;
+ get_task_comm(bo->gems.creator.process_name, current->group_leader);
+}
+
+static void panthor_gem_debugfs_bo_add(struct panthor_gem_object *bo)
+{
+ struct panthor_device *ptdev = container_of(bo->base.base.dev,
+ struct panthor_device, base);
+
+ mutex_lock(&ptdev->gems.lock);
+ list_add_tail(&bo->gems.node, &ptdev->gems.node);
+ mutex_unlock(&ptdev->gems.lock);
+}
+
+static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo)
+{
+ struct panthor_device *ptdev = container_of(bo->base.base.dev,
+ struct panthor_device, base);
+
+ if (list_empty(&bo->gems.node))
+ return;
+
+ mutex_lock(&ptdev->gems.lock);
+ list_del_init(&bo->gems.node);
+ mutex_unlock(&ptdev->gems.lock);
+}
+#else
+static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo) {}
+static void panthor_gem_debugfs_bo_add(struct panthor_gem_object *bo) {}
+static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo) {}
+#endif
+
static void panthor_gem_free_object(struct drm_gem_object *obj)
{
struct panthor_gem_object *bo = to_panthor_bo(obj);
struct drm_gem_object *vm_root_gem = bo->exclusive_vm_root_gem;
+ panthor_gem_debugfs_bo_rm(bo);
+
kfree(bo->label.str);
mutex_destroy(&bo->label.lock);
@@ -201,6 +240,8 @@ struct drm_gem_object *panthor_gem_create_object(struct drm_device *ddev, size_t
drm_gem_gpuva_set_lock(&obj->base.base, &obj->gpuva_list_lock);
mutex_init(&obj->label.lock);
+ panthor_gem_debugfs_bo_init(obj);
+
return &obj->base.base;
}
@@ -249,6 +290,8 @@ panthor_gem_create_with_handle(struct drm_file *file,
/* drop reference from allocate - handle holds it now. */
drm_gem_object_put(&shmem->base);
+ panthor_gem_debugfs_bo_add(bo);
+
return ret;
}
@@ -271,3 +314,90 @@ panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo *bo, const char *label)
{
panthor_gem_bo_set_label(bo->obj, kstrdup_const(label, GFP_KERNEL));
}
+
+#ifdef CONFIG_DEBUG_FS
+static bool panfrost_gem_print_flag(const char *name,
+ bool is_set,
+ bool other_flags_printed,
+ struct seq_file *m)
+{
+ if (is_set)
+ seq_printf(m, "%s%s", other_flags_printed ? "," : "", name);
+
+ return is_set | other_flags_printed;
+}
+
+struct gem_size_totals {
+ size_t size;
+ size_t resident;
+ size_t reclaimable;
+};
+
+static void panthor_gem_debugfs_bo_print(struct panthor_gem_object *bo,
+ struct seq_file *m,
+ struct gem_size_totals *totals)
+{
+ unsigned int refcount = kref_read(&bo->base.base.refcount);
+ char creator_info[32] = {};
+ bool has_flags = false;
+ size_t resident_size;
+
+ /* Skip BOs being destroyed. */
+ if (!refcount)
+ return;
+
+ resident_size = bo->base.pages != NULL ? bo->base.base.size : 0;
+
+ snprintf(creator_info, sizeof(creator_info),
+ "%s/%d", bo->gems.creator.process_name, bo->gems.creator.tgid);
+ seq_printf(m, "%-32s%-16d%-16d%-16zd%-16zd%-16lx",
+ creator_info,
+ bo->base.base.name,
+ refcount,
+ bo->base.base.size,
+ resident_size,
+ drm_vma_node_start(&bo->base.base.vma_node));
+
+ seq_puts(m, "(");
+ has_flags = panfrost_gem_print_flag("imported", bo->base.base.import_attach != NULL,
+ has_flags, m);
+ has_flags = panfrost_gem_print_flag("exported", bo->base.base.dma_buf != NULL,
+ has_flags, m);
+ if (bo->base.madv < 0)
+ has_flags = panfrost_gem_print_flag("purged", true, has_flags, m);
+ else if (bo->base.madv > 0)
+ has_flags = panfrost_gem_print_flag("purgeable", true, has_flags, m);
+ if (!has_flags)
+ seq_puts(m, "none");
+ seq_puts(m, ")");
+
+ mutex_lock(&bo->label.lock);
+ seq_printf(m, "%-16s%-60s", "", bo->label.str ? : NULL);
+ mutex_unlock(&bo->label.lock);
+ seq_puts(m, "\n");
+
+ totals->size += bo->base.base.size;
+ totals->resident += resident_size;
+ if (bo->base.madv > 0)
+ totals->reclaimable += resident_size;
+}
+
+void panthor_gem_debugfs_print_bos(struct panthor_device *ptdev,
+ struct seq_file *m)
+{
+ struct gem_size_totals totals = {0};
+ struct panthor_gem_object *bo;
+
+ seq_puts(m, "created-by global-name refcount size resident-size file-offset flags label\n");
+ seq_puts(m, "------------------------------------------------------------------------------------------------------------------------------------------------\n");
+
+ scoped_guard(mutex, &ptdev->gems.lock) {
+ list_for_each_entry(bo, &ptdev->gems.node, gems.node)
+ panthor_gem_debugfs_bo_print(bo, m, &totals);
+ }
+
+ seq_puts(m, "================================================================================================================================================\n");
+ seq_printf(m, "Total size: %zd, Total resident: %zd, Total reclaimable: %zd\n",
+ totals.size, totals.resident, totals.reclaimable);
+}
+#endif
diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
index 0582826b341a..7c896ec35801 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.h
+++ b/drivers/gpu/drm/panthor/panthor_gem.h
@@ -13,6 +13,26 @@
struct panthor_vm;
+/**
+ * struct panthor_gem_debugfs - GEM object's DebugFS list information
+ */
+struct panthor_gem_debugfs {
+ /**
+ * @node: Node used to insert the object in the device-wide list of
+ * GEM objects, to display information about it through a DebugFS file.
+ */
+ struct list_head node;
+
+ /** @creator: Information about the UM process which created the GEM. */
+ struct {
+ /** @creator.process_name: Group leader name in owning thread's process */
+ char process_name[TASK_COMM_LEN];
+
+ /** @creator.tgid: PID of the thread's group leader within its process */
+ pid_t tgid;
+ } creator;
+};
+
/**
* struct panthor_gem_object - Driver specific GEM object.
*/
@@ -60,6 +80,10 @@ struct panthor_gem_object {
/** @lock.str: Protects access to the @label.str field. */
struct mutex lock;
} label;
+
+#ifdef CONFIG_DEBUG_FS
+ struct panthor_gem_debugfs gems;
+#endif
};
/**
@@ -155,4 +179,9 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
+#ifdef CONFIG_DEBUG_FS
+void panthor_gem_debugfs_print_bos(struct panthor_device *pfdev,
+ struct seq_file *m);
+#endif
+
#endif /* __PANTHOR_GEM_H__ */
--
2.48.1