diff mbox series

[v2,01/12] drm/panfrost: Make sure MMU context lifetime is not bound to panfrost_priv

Message ID 20210621133907.1683899-2-boris.brezillon@collabora.com (mailing list archive)
State New, archived
Headers show
Series drm/panfrost: Misc fixes/improvements | expand

Commit Message

Boris Brezillon June 21, 2021, 1:38 p.m. UTC
Jobs can be in-flight when the file descriptor is closed (either because
the process did not terminate properly, or because it didn't wait for
all GPU jobs to be finished), and apparently panfrost_job_close() does
not cancel already running jobs. Let's refcount the MMU context object
so it's lifetime is no longer bound to the FD lifetime and running jobs
can finish properly without generating spurious page faults.

Reported-by: Icecream95 <ixn@keemail.me>
Fixes: 7282f7645d06 ("drm/panfrost: Implement per FD address spaces")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
---
 drivers/gpu/drm/panfrost/panfrost_device.h |   8 +-
 drivers/gpu/drm/panfrost/panfrost_drv.c    |  50 ++-----
 drivers/gpu/drm/panfrost/panfrost_gem.c    |  20 ++-
 drivers/gpu/drm/panfrost/panfrost_job.c    |   4 +-
 drivers/gpu/drm/panfrost/panfrost_mmu.c    | 160 ++++++++++++++-------
 drivers/gpu/drm/panfrost/panfrost_mmu.h    |   5 +-
 6 files changed, 136 insertions(+), 111 deletions(-)

Comments

Alyssa Rosenzweig June 21, 2021, 1:57 p.m. UTC | #1
> Jobs can be in-flight when the file descriptor is closed (either because
> the process did not terminate properly, or because it didn't wait for
> all GPU jobs to be finished), and apparently panfrost_job_close() does
> not cancel already running jobs. Let's refcount the MMU context object
> so it's lifetime is no longer bound to the FD lifetime and running jobs
> can finish properly without generating spurious page faults.

Remind me - why can't we hard stop in-flight jobs when the fd is closed?
I've seen cases where kill -9'ing a badly behaved process doesn't end
the fault storm, or unfreeze the desktop.
Steven Price June 21, 2021, 2:29 p.m. UTC | #2
On 21/06/2021 14:57, Alyssa Rosenzweig wrote:
>> Jobs can be in-flight when the file descriptor is closed (either because
>> the process did not terminate properly, or because it didn't wait for
>> all GPU jobs to be finished), and apparently panfrost_job_close() does
>> not cancel already running jobs. Let's refcount the MMU context object
>> so it's lifetime is no longer bound to the FD lifetime and running jobs
>> can finish properly without generating spurious page faults.
> 
> Remind me - why can't we hard stop in-flight jobs when the fd is closed?
> I've seen cases where kill -9'ing a badly behaved process doesn't end
> the fault storm, or unfreeze the desktop.
> 

Hard-stopping the in-flight jobs would also make sense. But unless we
want to actually hang the close() then there will be a period between
issuing the hard-stop and actually having completed all jobs in the context.

But equally to be fair I've been cherry-picking this patch myself for
quite some time, so we should just merge it and improve from there. So
you can have my:

Reviewed-by: Steven Price <steven.price@arm.com>
Boris Brezillon June 21, 2021, 2:44 p.m. UTC | #3
On Mon, 21 Jun 2021 15:29:55 +0100
Steven Price <steven.price@arm.com> wrote:

> On 21/06/2021 14:57, Alyssa Rosenzweig wrote:
> >> Jobs can be in-flight when the file descriptor is closed (either because
> >> the process did not terminate properly, or because it didn't wait for
> >> all GPU jobs to be finished), and apparently panfrost_job_close() does
> >> not cancel already running jobs. Let's refcount the MMU context object
> >> so it's lifetime is no longer bound to the FD lifetime and running jobs
> >> can finish properly without generating spurious page faults.  
> > 
> > Remind me - why can't we hard stop in-flight jobs when the fd is closed?
> > I've seen cases where kill -9'ing a badly behaved process doesn't end
> > the fault storm, or unfreeze the desktop.
> >   
> 
> Hard-stopping the in-flight jobs would also make sense. But unless we
> want to actually hang the close() then there will be a period between
> issuing the hard-stop and actually having completed all jobs in the context.

Patch 10 is doing that, I just didn't want to backport all the
dependencies, so I kept it split in 2 halves: one patch fixing the
use-after-free bug, and the other part killing in-flight jobs.

> 
> But equally to be fair I've been cherry-picking this patch myself for
> quite some time, so we should just merge it and improve from there. So
> you can have my:
> 
> Reviewed-by: Steven Price <steven.price@arm.com>
Boris Brezillon June 24, 2021, 8:03 a.m. UTC | #4
On Mon, 21 Jun 2021 15:38:56 +0200
Boris Brezillon <boris.brezillon@collabora.com> wrote:

> Jobs can be in-flight when the file descriptor is closed (either because
> the process did not terminate properly, or because it didn't wait for
> all GPU jobs to be finished), and apparently panfrost_job_close() does
> not cancel already running jobs. Let's refcount the MMU context object
> so it's lifetime is no longer bound to the FD lifetime and running jobs
> can finish properly without generating spurious page faults.
> 
> Reported-by: Icecream95 <ixn@keemail.me>
> Fixes: 7282f7645d06 ("drm/panfrost: Implement per FD address spaces")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>

Queued this patch to drm-misc-next. I'll respin the rest of this series.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index f614e98771e4..8b2cdb8c701d 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -121,8 +121,12 @@  struct panfrost_device {
 };
 
 struct panfrost_mmu {
+	struct panfrost_device *pfdev;
+	struct kref refcount;
 	struct io_pgtable_cfg pgtbl_cfg;
 	struct io_pgtable_ops *pgtbl_ops;
+	struct drm_mm mm;
+	spinlock_t mm_lock;
 	int as;
 	atomic_t as_count;
 	struct list_head list;
@@ -133,9 +137,7 @@  struct panfrost_file_priv {
 
 	struct drm_sched_entity sched_entity[NUM_JOB_SLOTS];
 
-	struct panfrost_mmu mmu;
-	struct drm_mm mm;
-	spinlock_t mm_lock;
+	struct panfrost_mmu *mmu;
 };
 
 static inline struct panfrost_device *to_panfrost_device(struct drm_device *ddev)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 075ec0ef746c..945133db1857 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -417,7 +417,7 @@  static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
 		 * anyway, so let's not bother.
 		 */
 		if (!list_is_singular(&bo->mappings.list) ||
-		    WARN_ON_ONCE(first->mmu != &priv->mmu)) {
+		    WARN_ON_ONCE(first->mmu != priv->mmu)) {
 			ret = -EINVAL;
 			goto out_unlock_mappings;
 		}
@@ -449,32 +449,6 @@  int panfrost_unstable_ioctl_check(void)
 	return 0;
 }
 
-#define PFN_4G		(SZ_4G >> PAGE_SHIFT)
-#define PFN_4G_MASK	(PFN_4G - 1)
-#define PFN_16M		(SZ_16M >> PAGE_SHIFT)
-
-static void panfrost_drm_mm_color_adjust(const struct drm_mm_node *node,
-					 unsigned long color,
-					 u64 *start, u64 *end)
-{
-	/* Executable buffers can't start or end on a 4GB boundary */
-	if (!(color & PANFROST_BO_NOEXEC)) {
-		u64 next_seg;
-
-		if ((*start & PFN_4G_MASK) == 0)
-			(*start)++;
-
-		if ((*end & PFN_4G_MASK) == 0)
-			(*end)--;
-
-		next_seg = ALIGN(*start, PFN_4G);
-		if (next_seg - *start <= PFN_16M)
-			*start = next_seg + 1;
-
-		*end = min(*end, ALIGN(*start, PFN_4G) - 1);
-	}
-}
-
 static int
 panfrost_open(struct drm_device *dev, struct drm_file *file)
 {
@@ -489,15 +463,11 @@  panfrost_open(struct drm_device *dev, struct drm_file *file)
 	panfrost_priv->pfdev = pfdev;
 	file->driver_priv = panfrost_priv;
 
-	spin_lock_init(&panfrost_priv->mm_lock);
-
-	/* 4G enough for now. can be 48-bit */
-	drm_mm_init(&panfrost_priv->mm, SZ_32M >> PAGE_SHIFT, (SZ_4G - SZ_32M) >> PAGE_SHIFT);
-	panfrost_priv->mm.color_adjust = panfrost_drm_mm_color_adjust;
-
-	ret = panfrost_mmu_pgtable_alloc(panfrost_priv);
-	if (ret)
-		goto err_pgtable;
+	panfrost_priv->mmu = panfrost_mmu_ctx_create(pfdev);
+	if (IS_ERR(panfrost_priv->mmu)) {
+		ret = PTR_ERR(panfrost_priv->mmu);
+		goto err_free;
+	}
 
 	ret = panfrost_job_open(panfrost_priv);
 	if (ret)
@@ -506,9 +476,8 @@  panfrost_open(struct drm_device *dev, struct drm_file *file)
 	return 0;
 
 err_job:
-	panfrost_mmu_pgtable_free(panfrost_priv);
-err_pgtable:
-	drm_mm_takedown(&panfrost_priv->mm);
+	panfrost_mmu_ctx_put(panfrost_priv->mmu);
+err_free:
 	kfree(panfrost_priv);
 	return ret;
 }
@@ -521,8 +490,7 @@  panfrost_postclose(struct drm_device *dev, struct drm_file *file)
 	panfrost_perfcnt_close(file);
 	panfrost_job_close(panfrost_priv);
 
-	panfrost_mmu_pgtable_free(panfrost_priv);
-	drm_mm_takedown(&panfrost_priv->mm);
+	panfrost_mmu_ctx_put(panfrost_priv->mmu);
 	kfree(panfrost_priv);
 }
 
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 3e0723bc36bd..23377481f4e3 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -60,7 +60,7 @@  panfrost_gem_mapping_get(struct panfrost_gem_object *bo,
 
 	mutex_lock(&bo->mappings.lock);
 	list_for_each_entry(iter, &bo->mappings.list, node) {
-		if (iter->mmu == &priv->mmu) {
+		if (iter->mmu == priv->mmu) {
 			kref_get(&iter->refcount);
 			mapping = iter;
 			break;
@@ -74,16 +74,13 @@  panfrost_gem_mapping_get(struct panfrost_gem_object *bo,
 static void
 panfrost_gem_teardown_mapping(struct panfrost_gem_mapping *mapping)
 {
-	struct panfrost_file_priv *priv;
-
 	if (mapping->active)
 		panfrost_mmu_unmap(mapping);
 
-	priv = container_of(mapping->mmu, struct panfrost_file_priv, mmu);
-	spin_lock(&priv->mm_lock);
+	spin_lock(&mapping->mmu->mm_lock);
 	if (drm_mm_node_allocated(&mapping->mmnode))
 		drm_mm_remove_node(&mapping->mmnode);
-	spin_unlock(&priv->mm_lock);
+	spin_unlock(&mapping->mmu->mm_lock);
 }
 
 static void panfrost_gem_mapping_release(struct kref *kref)
@@ -94,6 +91,7 @@  static void panfrost_gem_mapping_release(struct kref *kref)
 
 	panfrost_gem_teardown_mapping(mapping);
 	drm_gem_object_put(&mapping->obj->base.base);
+	panfrost_mmu_ctx_put(mapping->mmu);
 	kfree(mapping);
 }
 
@@ -143,11 +141,11 @@  int panfrost_gem_open(struct drm_gem_object *obj, struct drm_file *file_priv)
 	else
 		align = size >= SZ_2M ? SZ_2M >> PAGE_SHIFT : 0;
 
-	mapping->mmu = &priv->mmu;
-	spin_lock(&priv->mm_lock);
-	ret = drm_mm_insert_node_generic(&priv->mm, &mapping->mmnode,
+	mapping->mmu = panfrost_mmu_ctx_get(priv->mmu);
+	spin_lock(&mapping->mmu->mm_lock);
+	ret = drm_mm_insert_node_generic(&mapping->mmu->mm, &mapping->mmnode,
 					 size >> PAGE_SHIFT, align, color, 0);
-	spin_unlock(&priv->mm_lock);
+	spin_unlock(&mapping->mmu->mm_lock);
 	if (ret)
 		goto err;
 
@@ -176,7 +174,7 @@  void panfrost_gem_close(struct drm_gem_object *obj, struct drm_file *file_priv)
 
 	mutex_lock(&bo->mappings.lock);
 	list_for_each_entry(iter, &bo->mappings.list, node) {
-		if (iter->mmu == &priv->mmu) {
+		if (iter->mmu == priv->mmu) {
 			mapping = iter;
 			list_del(&iter->node);
 			break;
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 2df3e999a38d..3757c6eb3023 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -165,7 +165,7 @@  static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
 		return;
 	}
 
-	cfg = panfrost_mmu_as_get(pfdev, &job->file_priv->mmu);
+	cfg = panfrost_mmu_as_get(pfdev, job->file_priv->mmu);
 
 	job_write(pfdev, JS_HEAD_NEXT_LO(js), jc_head & 0xFFFFFFFF);
 	job_write(pfdev, JS_HEAD_NEXT_HI(js), jc_head >> 32);
@@ -527,7 +527,7 @@  static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
 			if (job) {
 				pfdev->jobs[j] = NULL;
 
-				panfrost_mmu_as_put(pfdev, &job->file_priv->mmu);
+				panfrost_mmu_as_put(pfdev, job->file_priv->mmu);
 				panfrost_devfreq_record_idle(&pfdev->pfdevfreq);
 
 				dma_fence_signal_locked(job->done_fence);
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 0581186ebfb3..569509c2ba27 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -1,5 +1,8 @@ 
 // SPDX-License-Identifier:	GPL-2.0
 /* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
+
+#include <drm/panfrost_drm.h>
+
 #include <linux/atomic.h>
 #include <linux/bitfield.h>
 #include <linux/delay.h>
@@ -337,7 +340,7 @@  static void mmu_tlb_inv_context_s1(void *cookie)
 
 static void mmu_tlb_sync_context(void *cookie)
 {
-	//struct panfrost_device *pfdev = cookie;
+	//struct panfrost_mmu *mmu = cookie;
 	// TODO: Wait 1000 GPU cycles for HW_ISSUE_6367/T60X
 }
 
@@ -352,57 +355,10 @@  static const struct iommu_flush_ops mmu_tlb_ops = {
 	.tlb_flush_walk = mmu_tlb_flush_walk,
 };
 
-int panfrost_mmu_pgtable_alloc(struct panfrost_file_priv *priv)
-{
-	struct panfrost_mmu *mmu = &priv->mmu;
-	struct panfrost_device *pfdev = priv->pfdev;
-
-	INIT_LIST_HEAD(&mmu->list);
-	mmu->as = -1;
-
-	mmu->pgtbl_cfg = (struct io_pgtable_cfg) {
-		.pgsize_bitmap	= SZ_4K | SZ_2M,
-		.ias		= FIELD_GET(0xff, pfdev->features.mmu_features),
-		.oas		= FIELD_GET(0xff00, pfdev->features.mmu_features),
-		.coherent_walk	= pfdev->coherent,
-		.tlb		= &mmu_tlb_ops,
-		.iommu_dev	= pfdev->dev,
-	};
-
-	mmu->pgtbl_ops = alloc_io_pgtable_ops(ARM_MALI_LPAE, &mmu->pgtbl_cfg,
-					      priv);
-	if (!mmu->pgtbl_ops)
-		return -EINVAL;
-
-	return 0;
-}
-
-void panfrost_mmu_pgtable_free(struct panfrost_file_priv *priv)
-{
-	struct panfrost_device *pfdev = priv->pfdev;
-	struct panfrost_mmu *mmu = &priv->mmu;
-
-	spin_lock(&pfdev->as_lock);
-	if (mmu->as >= 0) {
-		pm_runtime_get_noresume(pfdev->dev);
-		if (pm_runtime_active(pfdev->dev))
-			panfrost_mmu_disable(pfdev, mmu->as);
-		pm_runtime_put_autosuspend(pfdev->dev);
-
-		clear_bit(mmu->as, &pfdev->as_alloc_mask);
-		clear_bit(mmu->as, &pfdev->as_in_use_mask);
-		list_del(&mmu->list);
-	}
-	spin_unlock(&pfdev->as_lock);
-
-	free_io_pgtable_ops(mmu->pgtbl_ops);
-}
-
 static struct panfrost_gem_mapping *
 addr_to_mapping(struct panfrost_device *pfdev, int as, u64 addr)
 {
 	struct panfrost_gem_mapping *mapping = NULL;
-	struct panfrost_file_priv *priv;
 	struct drm_mm_node *node;
 	u64 offset = addr >> PAGE_SHIFT;
 	struct panfrost_mmu *mmu;
@@ -415,11 +371,10 @@  addr_to_mapping(struct panfrost_device *pfdev, int as, u64 addr)
 	goto out;
 
 found_mmu:
-	priv = container_of(mmu, struct panfrost_file_priv, mmu);
 
-	spin_lock(&priv->mm_lock);
+	spin_lock(&mmu->mm_lock);
 
-	drm_mm_for_each_node(node, &priv->mm) {
+	drm_mm_for_each_node(node, &mmu->mm) {
 		if (offset >= node->start &&
 		    offset < (node->start + node->size)) {
 			mapping = drm_mm_node_to_panfrost_mapping(node);
@@ -429,7 +384,7 @@  addr_to_mapping(struct panfrost_device *pfdev, int as, u64 addr)
 		}
 	}
 
-	spin_unlock(&priv->mm_lock);
+	spin_unlock(&mmu->mm_lock);
 out:
 	spin_unlock(&pfdev->as_lock);
 	return mapping;
@@ -542,6 +497,107 @@  static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 	return ret;
 }
 
+static void panfrost_mmu_release_ctx(struct kref *kref)
+{
+	struct panfrost_mmu *mmu = container_of(kref, struct panfrost_mmu,
+						refcount);
+	struct panfrost_device *pfdev = mmu->pfdev;
+
+	spin_lock(&pfdev->as_lock);
+	if (mmu->as >= 0) {
+		pm_runtime_get_noresume(pfdev->dev);
+		if (pm_runtime_active(pfdev->dev))
+			panfrost_mmu_disable(pfdev, mmu->as);
+		pm_runtime_put_autosuspend(pfdev->dev);
+
+		clear_bit(mmu->as, &pfdev->as_alloc_mask);
+		clear_bit(mmu->as, &pfdev->as_in_use_mask);
+		list_del(&mmu->list);
+	}
+	spin_unlock(&pfdev->as_lock);
+
+	free_io_pgtable_ops(mmu->pgtbl_ops);
+	drm_mm_takedown(&mmu->mm);
+	kfree(mmu);
+}
+
+void panfrost_mmu_ctx_put(struct panfrost_mmu *mmu)
+{
+	kref_put(&mmu->refcount, panfrost_mmu_release_ctx);
+}
+
+struct panfrost_mmu *panfrost_mmu_ctx_get(struct panfrost_mmu *mmu)
+{
+	kref_get(&mmu->refcount);
+
+	return mmu;
+}
+
+#define PFN_4G		(SZ_4G >> PAGE_SHIFT)
+#define PFN_4G_MASK	(PFN_4G - 1)
+#define PFN_16M		(SZ_16M >> PAGE_SHIFT)
+
+static void panfrost_drm_mm_color_adjust(const struct drm_mm_node *node,
+					 unsigned long color,
+					 u64 *start, u64 *end)
+{
+	/* Executable buffers can't start or end on a 4GB boundary */
+	if (!(color & PANFROST_BO_NOEXEC)) {
+		u64 next_seg;
+
+		if ((*start & PFN_4G_MASK) == 0)
+			(*start)++;
+
+		if ((*end & PFN_4G_MASK) == 0)
+			(*end)--;
+
+		next_seg = ALIGN(*start, PFN_4G);
+		if (next_seg - *start <= PFN_16M)
+			*start = next_seg + 1;
+
+		*end = min(*end, ALIGN(*start, PFN_4G) - 1);
+	}
+}
+
+struct panfrost_mmu *panfrost_mmu_ctx_create(struct panfrost_device *pfdev)
+{
+	struct panfrost_mmu *mmu;
+
+	mmu = kzalloc(sizeof(*mmu), GFP_KERNEL);
+	if (!mmu)
+		return ERR_PTR(-ENOMEM);
+
+	mmu->pfdev = pfdev;
+	spin_lock_init(&mmu->mm_lock);
+
+	/* 4G enough for now. can be 48-bit */
+	drm_mm_init(&mmu->mm, SZ_32M >> PAGE_SHIFT, (SZ_4G - SZ_32M) >> PAGE_SHIFT);
+	mmu->mm.color_adjust = panfrost_drm_mm_color_adjust;
+
+	INIT_LIST_HEAD(&mmu->list);
+	mmu->as = -1;
+
+	mmu->pgtbl_cfg = (struct io_pgtable_cfg) {
+		.pgsize_bitmap	= SZ_4K | SZ_2M,
+		.ias		= FIELD_GET(0xff, pfdev->features.mmu_features),
+		.oas		= FIELD_GET(0xff00, pfdev->features.mmu_features),
+		.coherent_walk	= pfdev->coherent,
+		.tlb		= &mmu_tlb_ops,
+		.iommu_dev	= pfdev->dev,
+	};
+
+	mmu->pgtbl_ops = alloc_io_pgtable_ops(ARM_MALI_LPAE, &mmu->pgtbl_cfg,
+					      mmu);
+	if (!mmu->pgtbl_ops) {
+		kfree(mmu);
+		return ERR_PTR(-EINVAL);
+	}
+
+	kref_init(&mmu->refcount);
+
+	return mmu;
+}
+
 static const char *access_type_name(struct panfrost_device *pfdev,
 		u32 fault_status)
 {
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.h b/drivers/gpu/drm/panfrost/panfrost_mmu.h
index 44fc2edf63ce..cc2a0d307feb 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.h
@@ -18,7 +18,8 @@  void panfrost_mmu_reset(struct panfrost_device *pfdev);
 u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
 void panfrost_mmu_as_put(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
 
-int panfrost_mmu_pgtable_alloc(struct panfrost_file_priv *priv);
-void panfrost_mmu_pgtable_free(struct panfrost_file_priv *priv);
+struct panfrost_mmu *panfrost_mmu_ctx_get(struct panfrost_mmu *mmu);
+void panfrost_mmu_ctx_put(struct panfrost_mmu *mmu);
+struct panfrost_mmu *panfrost_mmu_ctx_create(struct panfrost_device *pfdev);
 
 #endif