[PATCH v5 4/4] drm/panthor: show device-wide list of DRM GEM objects over DebugFS
From: Adrián Larumbe
Date: Tue Apr 08 2025 - 18:33:44 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 GEM
state flags.
There's also a kflags field for the type of BO, which tells us whether
it's a kernel BO and/or mapped onto the FW's address space.
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 | 168 +++++++++++++++++++++++
drivers/gpu/drm/panthor/panthor_gem.h | 65 +++++++++
5 files changed, 275 insertions(+)
diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index a9da1d1eeb70..b776e1a2e4f3 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -184,6 +184,11 @@ int panthor_device_init(struct panthor_device *ptdev)
if (ret)
return ret;
+#ifdef CONFIG_DEBUG_FS
+ drmm_mutex_init(&ptdev->base, &ptdev->gems.lock);
+ INIT_LIST_HEAD(&ptdev->gems.node);
+#endif
+
atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED);
p = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!p)
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 163c027562aa..935ca9e6138e 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1534,9 +1534,35 @@ 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 742192c42f58..439f2ae4e6bb 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>
@@ -10,14 +11,51 @@
#include <drm/panthor_drm.h>
#include "panthor_device.h"
+#include "panthor_fw.h"
#include "panthor_gem.h"
#include "panthor_mmu.h"
+#ifdef CONFIG_DEBUG_FS
+static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,
+ struct panthor_gem_object *bo)
+{
+ INIT_LIST_HEAD(&bo->debugfs.node);
+
+ bo->debugfs.creator.tgid = current->group_leader->pid;
+ get_task_comm(bo->debugfs.creator.process_name, current->group_leader);
+
+ mutex_lock(&ptdev->gems.lock);
+ list_add_tail(&bo->debugfs.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->debugfs.node))
+ return;
+
+ mutex_lock(&ptdev->gems.lock);
+ list_del_init(&bo->debugfs.node);
+ mutex_unlock(&ptdev->gems.lock);
+}
+
+#else
+static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,
+ 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);
+
/*
* Label might have been allocated with kstrdup_const(),
* we need to take that into account when freeing the memory
@@ -86,6 +124,7 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
struct drm_gem_shmem_object *obj;
struct panthor_kernel_bo *kbo;
struct panthor_gem_object *bo;
+ u32 debug_flags = PANTHOR_DEBUGFS_BO_FLAGS_KERNEL;
int ret;
if (drm_WARN_ON(&ptdev->base, !vm))
@@ -105,7 +144,11 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
kbo->obj = &obj->base;
bo->flags = bo_flags;
+ if (vm == panthor_fw_vm(ptdev))
+ debug_flags |= PANTHOR_DEBUGFS_BO_FW_FLAG_MAPPED;
+
panthor_gem_kernel_bo_set_label(kbo, name);
+ panthor_gem_debugfs_bo_set_mask(to_panthor_bo(kbo->obj), debug_flags);
/* The system and GPU MMU page size might differ, which becomes a
* problem for FW sections that need to be mapped at explicit address
@@ -208,6 +251,8 @@ 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_add(ptdev, obj);
+
return &obj->base.base;
}
@@ -256,6 +301,8 @@ 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_set_mask(bo, 0);
+
return ret;
}
@@ -287,3 +334,124 @@ panthor_gem_kernel_bo_set_label(struct panthor_kernel_bo *bo, const char *label)
panthor_gem_bo_set_label(bo->obj, kstrdup_const(str, GFP_KERNEL));
}
+
+#ifdef CONFIG_DEBUG_FS
+static void
+panthor_gem_debugfs_print_flags(struct seq_file *m,
+ const char *names[],
+ u32 name_count,
+ u32 flags)
+{
+ bool first = true;
+
+ seq_puts(m, "(");
+
+ if (!flags)
+ seq_puts(m, "none");
+
+ while (flags) {
+ u32 bit = fls(flags) - 1;
+
+ if (!first)
+ seq_puts(m, ",");
+
+ if (bit >= name_count || !names[bit])
+ seq_printf(m, "unknown-bit%d", bit);
+ else
+ seq_printf(m, "%s", names[bit]);
+
+ first = false;
+ flags &= ~BIT(bit);
+ }
+
+ seq_puts(m, ")");
+}
+
+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] = {};
+ u32 gem_state_flags = 0;
+ size_t resident_size;
+
+ static const char *gem_status_flags[] = {
+ "imported", "exported", "purged", "purgeable"
+ };
+
+ static const char *panthor_bo_flags[] = {
+ "kernel", "fw"
+ };
+
+ /* 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->debugfs.creator.process_name, bo->debugfs.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));
+
+
+ if (bo->base.base.import_attach != NULL)
+ gem_state_flags |= PANTHOR_DEBUGFS_GEM_IMPORTED;
+ if (bo->base.base.dma_buf != NULL)
+ gem_state_flags |= PANTHOR_DEBUGFS_GEM_EXPORTED;
+ if (bo->base.madv < 0)
+ gem_state_flags |= PANTHOR_DEBUGFS_GEM_PURGED;
+ if (bo->base.madv)
+ gem_state_flags |= PANTHOR_DEBUGFS_GEM_PURGEABLE;
+
+ panthor_gem_debugfs_print_flags(m, gem_status_flags,
+ sizeof(gem_status_flags), gem_state_flags);
+ seq_printf(m, "%-4s", "");
+ panthor_gem_debugfs_print_flags(m, panthor_bo_flags, sizeof(panthor_bo_flags),
+ bo->debugfs.flags & (u32)~PANTHOR_DEBUGFS_BO_FLAG_INITIALISED);
+
+ mutex_lock(&bo->label.lock);
+ seq_printf(m, "%-6s%-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 state kflags label\n");
+ seq_puts(m, "------------------------------------------------------------------------------------------------------------------------------------------------\n");
+
+ scoped_guard(mutex, &ptdev->gems.lock) {
+ list_for_each_entry(bo, &ptdev->gems.node, debugfs.node) {
+ if (bo->debugfs.flags & PANTHOR_DEBUGFS_BO_FLAG_INITIALISED)
+ 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 49daa5088a0d..58575f38ee26 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.h
+++ b/drivers/gpu/drm/panthor/panthor_gem.h
@@ -15,6 +15,54 @@ struct panthor_vm;
#define PANTHOR_BO_LABEL_MAXLEN PAGE_SIZE
+enum panthor_debugfs_gem_state_flags {
+ /** @PANTHOR_DEBUGFS_GEM_IMPORTED: GEM BO is PRIME imported. */
+ PANTHOR_DEBUGFS_GEM_IMPORTED = BIT(0),
+
+ /** @PANTHOR_DEBUGFS_GEM_EXPORTED: GEM BO is PRIME exported. */
+ PANTHOR_DEBUGFS_GEM_EXPORTED = BIT(1),
+
+ /** @PANTHOR_DEBUGFS_GEM_PURGED: GEM BO was reclaimed by the shrinker. */
+ PANTHOR_DEBUGFS_GEM_PURGED = BIT(2),
+
+ /** @PANTHOR_DEBUGFS_GEM_PURGEABLE: GEM BO can be reclaimed by the shrinker. */
+ PANTHOR_DEBUGFS_GEM_PURGEABLE = BIT(3),
+};
+
+enum panthor_debugfs_bo_flags {
+ /** @PANTHOR_DEBUGFS_BO_KERNEL: BO is for kernel use only. */
+ PANTHOR_DEBUGFS_BO_FLAGS_KERNEL = BIT(0),
+
+ /** @PANTHOR_DEBUGFS_BO_FW_MAPPED: BO is mapped on the FW VM. */
+ PANTHOR_DEBUGFS_BO_FW_FLAG_MAPPED = BIT(1),
+
+ /** @PANTHOR_DEBUGFS_BO_INITIALISED: BO is ready for DebugFS display. */
+ PANTHOR_DEBUGFS_BO_FLAG_INITIALISED = BIT(31),
+};
+
+/**
+ * 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;
+
+ /** @bo_mask: Combination of panthor_debugfs_bo_flags flags */
+ u32 flags;
+};
+
/**
* struct panthor_gem_object - Driver specific GEM object.
*/
@@ -62,6 +110,10 @@ 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 debugfs;
+#endif
};
/**
@@ -157,4 +209,17 @@ 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);
+static inline void
+panthor_gem_debugfs_bo_set_mask(struct panthor_gem_object *bo, u32 type_mask)
+{
+ bo->debugfs.flags = type_mask | PANTHOR_DEBUGFS_BO_FLAG_INITIALISED;
+}
+
+#else
+void panthor_gem_debugfs_bo_set_mask(struct panthor_gem_object *bo, u32 type_mask) {};
+#endif
+
#endif /* __PANTHOR_GEM_H__ */
--
2.48.1