Introduce the 'panfrost.transparent_hugepage' boolean module parameter
(false by default). When the parameter is set to true, a new tmpfs
mount point is created and mounted using the 'huge=within_size'
option. It's then used at GEM object creation instead of the default
'shm_mnt' mount point in order to enable Transparent Hugepage (THP)
for the object (without having to rely on a system wide parameter).

Signed-off-by: Loïc Molinari <loic.molinari@collabora.com>
---
 drivers/gpu/drm/panfrost/panfrost_device.c |  4 +++
 drivers/gpu/drm/panfrost/panfrost_device.h |  2 ++
 drivers/gpu/drm/panfrost/panfrost_drv.c    |  6 +++++
 drivers/gpu/drm/panfrost/panfrost_drv.h    | 11 ++++++++
 drivers/gpu/drm/panfrost/panfrost_gem.c    | 29 +++++++++++++++++++++-
 drivers/gpu/drm/panfrost/panfrost_gem.h    |  3 +++
 6 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/panfrost/panfrost_drv.h

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
index 04bec27449cb..8f551c598a5c 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.c
+++ b/drivers/gpu/drm/panfrost/panfrost_device.c
@@ -12,6 +12,7 @@
 #include "panfrost_device.h"
 #include "panfrost_devfreq.h"
 #include "panfrost_features.h"
+#include "panfrost_gem.h"
 #include "panfrost_issues.h"
 #include "panfrost_gpu.h"
 #include "panfrost_job.h"
@@ -266,6 +267,8 @@ int panfrost_device_init(struct panfrost_device *pfdev)
 	if (err)
 		goto out_job;
 
+	panfrost_gem_init(pfdev);
+
 	return 0;
 out_job:
 	panfrost_job_fini(pfdev);
@@ -288,6 +291,7 @@ int panfrost_device_init(struct panfrost_device *pfdev)
 
 void panfrost_device_fini(struct panfrost_device *pfdev)
 {
+	panfrost_gem_fini(pfdev);
 	panfrost_perfcnt_fini(pfdev);
 	panfrost_job_fini(pfdev);
 	panfrost_mmu_fini(pfdev);
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 1e73efad02a8..b8f368aef9e4 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -177,6 +177,8 @@ struct panfrost_device {
 		spinlock_t lock;
 	} cycle_counter;
 
+	struct vfsmount *huge_mnt;
+
 #ifdef CONFIG_DEBUG_FS
 	struct panfrost_device_debugfs debugfs;
 #endif
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 22350ce8a08f..e376e70a3379 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -862,6 +862,12 @@ static const struct drm_driver panfrost_drm_driver = {
 #endif
 };
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+bool panfrost_transparent_hugepage;
+module_param_named(transparent_hugepage, panfrost_transparent_hugepage, bool, 0400);
+MODULE_PARM_DESC(transparent_hugepage, "Use a dedicated tmpfs mount point with Transparent Hugepage enabled (false = default)");
+#endif
+
 static int panfrost_probe(struct platform_device *pdev)
 {
 	struct panfrost_device *pfdev;
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.h b/drivers/gpu/drm/panfrost/panfrost_drv.h
new file mode 100644
index 000000000000..60454611b6a6
--- /dev/null
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.h
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0 or MIT
+/* Copyright 2025 Amazon.com, Inc. or its affiliates */
+
+#ifndef __PANFROST_DRV_H__
+#define __PANFROST_DRV_H__
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern bool panfrost_transparent_hugepage;
+#endif
+
+#endif
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 85d6289a6eda..e560934bbf76 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
+/* Copyright 2025 Amazon.com, Inc. or its affiliates */
 
 #include <linux/cleanup.h>
 #include <linux/err.h>
@@ -9,9 +10,34 @@
 
 #include <drm/panfrost_drm.h>
 #include "panfrost_device.h"
+#include "panfrost_drv.h"
 #include "panfrost_gem.h"
 #include "panfrost_mmu.h"
 
+void panfrost_gem_init(struct panfrost_device *pfdev)
+{
+	struct vfsmount *huge_mnt;
+
+	if (!panfrost_transparent_hugepage)
+		return;
+
+	huge_mnt = drm_gem_shmem_huge_mnt_create("within_size");
+	if (IS_ERR(huge_mnt)) {
+		drm_warn(pfdev->ddev, "Can't use Transparent Hugepage (%ld)\n",
+			 PTR_ERR(huge_mnt));
+		return;
+	}
+
+	pfdev->huge_mnt = huge_mnt;
+
+	drm_info(pfdev->ddev, "Using Transparent Hugepage\n");
+}
+
+void panfrost_gem_fini(struct panfrost_device *pfdev)
+{
+	drm_gem_shmem_huge_mnt_free(pfdev->huge_mnt);
+}
+
 #ifdef CONFIG_DEBUG_FS
 static void panfrost_gem_debugfs_bo_add(struct panfrost_device *pfdev,
 					struct panfrost_gem_object *bo)
@@ -305,6 +331,7 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t
 struct panfrost_gem_object *
 panfrost_gem_create(struct drm_device *dev, size_t size, u32 flags)
 {
+	struct panfrost_device *pfdev = dev->dev_private;
 	struct drm_gem_shmem_object *shmem;
 	struct panfrost_gem_object *bo;
 
@@ -312,7 +339,7 @@ panfrost_gem_create(struct drm_device *dev, size_t size, u32 flags)
 	if (flags & PANFROST_BO_HEAP)
 		size = roundup(size, SZ_2M);
 
-	shmem = drm_gem_shmem_create(dev, size);
+	shmem = drm_gem_shmem_create_with_mnt(dev, size, pfdev->huge_mnt);
 	if (IS_ERR(shmem))
 		return ERR_CAST(shmem);
 
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
index 8de3e76f2717..0e874d3c1363 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
@@ -124,6 +124,9 @@ drm_mm_node_to_panfrost_mapping(struct drm_mm_node *node)
 	return container_of(node, struct panfrost_gem_mapping, mmnode);
 }
 
+void panfrost_gem_init(struct panfrost_device *pfdev);
+void panfrost_gem_fini(struct panfrost_device *pfdev);
+
 struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t size);
 
 struct drm_gem_object *
-- 
2.47.3