drivers/gpu/drm/amd/amdkfd/kfd_process.c - third_party/kernel - Git at Google

 /*
  * Copyright 2014 Advanced Micro Devices, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */

 #include <linux/mutex.h>
 #include <linux/log2.h>
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/task.h>
 #include <linux/slab.h>
 #include <linux/amd-iommu.h>
 #include <linux/notifier.h>
 #include <linux/compat.h>
 #include <linux/mman.h>

 struct mm_struct;

 #include "kfd_priv.h"
 #include "kfd_dbgmgr.h"

 /*
  * List of struct kfd_process (field kfd_process).
  * Unique/indexed by mm_struct*
  */
 #define KFD_PROCESS_TABLE_SIZE 5 /* bits: 32 entries */
 static DEFINE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
 static DEFINE_MUTEX(kfd_processes_mutex);

 DEFINE_STATIC_SRCU(kfd_processes_srcu);

 static struct workqueue_struct *kfd_process_wq;

 static struct kfd_process *find_process(const struct task_struct *thread);
 static void kfd_process_ref_release(struct kref *ref);
 static struct kfd_process *create_process(const struct task_struct *thread,
 					struct file *filep);
 static int kfd_process_init_cwsr(struct kfd_process *p, struct file *filep);


 void kfd_process_create_wq(void)
 {
 	if (!kfd_process_wq)
 		kfd_process_wq = alloc_workqueue("kfd_process_wq", 0, 0);
 }

 void kfd_process_destroy_wq(void)
 {
 	if (kfd_process_wq) {
 		destroy_workqueue(kfd_process_wq);
 		kfd_process_wq = NULL;
 	}
 }

 struct kfd_process *kfd_create_process(struct file *filep)
 {
 	struct kfd_process *process;
 	struct task_struct *thread = current;

 	if (!thread->mm)
 		return ERR_PTR(-EINVAL);

 	/* Only the pthreads threading model is supported. */
 	if (thread->group_leader->mm != thread->mm)
 		return ERR_PTR(-EINVAL);

 	/*
 	 * take kfd processes mutex before starting of process creation
 	 * so there won't be a case where two threads of the same process
 	 * create two kfd_process structures
 	 */
 	mutex_lock(&kfd_processes_mutex);

 	/* A prior open of /dev/kfd could have already created the process. */
 	process = find_process(thread);
 	if (process)
 		pr_debug("Process already found\n");
 	else
 		process = create_process(thread, filep);

 	mutex_unlock(&kfd_processes_mutex);

 	return process;
 }

 struct kfd_process *kfd_get_process(const struct task_struct *thread)
 {
 	struct kfd_process *process;

 	if (!thread->mm)
 		return ERR_PTR(-EINVAL);

 	/* Only the pthreads threading model is supported. */
 	if (thread->group_leader->mm != thread->mm)
 		return ERR_PTR(-EINVAL);

 	process = find_process(thread);

 	return process;
 }

 static struct kfd_process *find_process_by_mm(const struct mm_struct *mm)
 {
 	struct kfd_process *process;

 	hash_for_each_possible_rcu(kfd_processes_table, process,
 					kfd_processes, (uintptr_t)mm)
 		if (process->mm == mm)
 			return process;

 	return NULL;
 }

 static struct kfd_process *find_process(const struct task_struct *thread)
 {
 	struct kfd_process *p;
 	int idx;

 	idx = srcu_read_lock(&kfd_processes_srcu);
 	p = find_process_by_mm(thread->mm);
 	srcu_read_unlock(&kfd_processes_srcu, idx);

 	return p;
 }

 void kfd_unref_process(struct kfd_process *p)
 {
 	kref_put(&p->ref, kfd_process_ref_release);
 }

 static void kfd_process_destroy_pdds(struct kfd_process *p)
 {
 	struct kfd_process_device *pdd, *temp;

 	list_for_each_entry_safe(pdd, temp, &p->per_device_data,
 				 per_device_list) {
 		pr_debug("Releasing pdd (topology id %d) for process (pasid %d)\n",
 				pdd->dev->id, p->pasid);

 		list_del(&pdd->per_device_list);

 		if (pdd->qpd.cwsr_kaddr)
 			free_pages((unsigned long)pdd->qpd.cwsr_kaddr,
 				get_order(KFD_CWSR_TBA_TMA_SIZE));

 		kfree(pdd);
 	}
 }

 /* No process locking is needed in this function, because the process
  * is not findable any more. We must assume that no other thread is
  * using it any more, otherwise we couldn't safely free the process
  * structure in the end.
  */
 static void kfd_process_wq_release(struct work_struct *work)
 {
 	struct kfd_process *p = container_of(work, struct kfd_process,
 					     release_work);
 	struct kfd_process_device *pdd;

 	pr_debug("Releasing process (pasid %d) in workqueue\n", p->pasid);

 	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
 		if (pdd->bound == PDD_BOUND)
 			amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
 	}

 	kfd_process_destroy_pdds(p);

 	kfd_event_free_process(p);

 	kfd_pasid_free(p->pasid);
 	kfd_free_process_doorbells(p);

 	mutex_destroy(&p->mutex);

 	put_task_struct(p->lead_thread);

 	kfree(p);
 }

 static void kfd_process_ref_release(struct kref *ref)
 {
 	struct kfd_process *p = container_of(ref, struct kfd_process, ref);

 	INIT_WORK(&p->release_work, kfd_process_wq_release);
 	queue_work(kfd_process_wq, &p->release_work);
 }

 static void kfd_process_destroy_delayed(struct rcu_head *rcu)
 {
 	struct kfd_process *p = container_of(rcu, struct kfd_process, rcu);

 	kfd_unref_process(p);
 }

 static void kfd_process_notifier_release(struct mmu_notifier *mn,
 					struct mm_struct *mm)
 {
 	struct kfd_process *p;
 	struct kfd_process_device *pdd = NULL;

 	/*
 	 * The kfd_process structure can not be free because the
 	 * mmu_notifier srcu is read locked
 	 */
 	p = container_of(mn, struct kfd_process, mmu_notifier);
 	if (WARN_ON(p->mm != mm))
 		return;

 	mutex_lock(&kfd_processes_mutex);
 	hash_del_rcu(&p->kfd_processes);
 	mutex_unlock(&kfd_processes_mutex);
 	synchronize_srcu(&kfd_processes_srcu);

 	mutex_lock(&p->mutex);

 	/* Iterate over all process device data structures and if the
 	 * pdd is in debug mode, we should first force unregistration,
 	 * then we will be able to destroy the queues
 	 */
 	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
 		struct kfd_dev *dev = pdd->dev;

 		mutex_lock(kfd_get_dbgmgr_mutex());
 		if (dev && dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
 			if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
 				kfd_dbgmgr_destroy(dev->dbgmgr);
 				dev->dbgmgr = NULL;
 			}
 		}
 		mutex_unlock(kfd_get_dbgmgr_mutex());
 	}

 	kfd_process_dequeue_from_all_devices(p);
 	pqm_uninit(&p->pqm);

 	/* Indicate to other users that MM is no longer valid */
 	p->mm = NULL;

 	mutex_unlock(&p->mutex);

 	mmu_notifier_unregister_no_release(&p->mmu_notifier, mm);
 	mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
 }

 static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
 	.release = kfd_process_notifier_release,
 };

 static int kfd_process_init_cwsr(struct kfd_process *p, struct file *filep)
 {
 	unsigned long  offset;
 	struct kfd_process_device *pdd = NULL;
 	struct kfd_dev *dev = NULL;
 	struct qcm_process_device *qpd = NULL;

 	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
 		dev = pdd->dev;
 		qpd = &pdd->qpd;
 		if (!dev->cwsr_enabled || qpd->cwsr_kaddr)
 			continue;
 		offset = (dev->id | KFD_MMAP_RESERVED_MEM_MASK) << PAGE_SHIFT;
 		qpd->tba_addr = (int64_t)vm_mmap(filep, 0,
 			KFD_CWSR_TBA_TMA_SIZE, PROT_READ | PROT_EXEC,
 			MAP_SHARED, offset);

 		if (IS_ERR_VALUE(qpd->tba_addr)) {
 			int err = qpd->tba_addr;

 			pr_err("Failure to set tba address. error %d.\n", err);
 			qpd->tba_addr = 0;
 			qpd->cwsr_kaddr = NULL;
 			return err;
 		}

 		memcpy(qpd->cwsr_kaddr, dev->cwsr_isa, dev->cwsr_isa_size);

 		qpd->tma_addr = qpd->tba_addr + KFD_CWSR_TMA_OFFSET;
 		pr_debug("set tba :0x%llx, tma:0x%llx, cwsr_kaddr:%p for pqm.\n",
 			qpd->tba_addr, qpd->tma_addr, qpd->cwsr_kaddr);
 	}

 	return 0;
 }

 static struct kfd_process *create_process(const struct task_struct *thread,
 					struct file *filep)
 {
 	struct kfd_process *process;
 	int err = -ENOMEM;

 	process = kzalloc(sizeof(*process), GFP_KERNEL);

 	if (!process)
 		goto err_alloc_process;

 	process->pasid = kfd_pasid_alloc();
 	if (process->pasid == 0)
 		goto err_alloc_pasid;

 	if (kfd_alloc_process_doorbells(process) < 0)
 		goto err_alloc_doorbells;

 	kref_init(&process->ref);

 	mutex_init(&process->mutex);

 	process->mm = thread->mm;

 	/* register notifier */
 	process->mmu_notifier.ops = &kfd_process_mmu_notifier_ops;
 	err = mmu_notifier_register(&process->mmu_notifier, process->mm);
 	if (err)
 		goto err_mmu_notifier;

 	hash_add_rcu(kfd_processes_table, &process->kfd_processes,
 			(uintptr_t)process->mm);

 	process->lead_thread = thread->group_leader;
 	get_task_struct(process->lead_thread);

 	INIT_LIST_HEAD(&process->per_device_data);

 	kfd_event_init_process(process);

 	err = pqm_init(&process->pqm, process);
 	if (err != 0)
 		goto err_process_pqm_init;

 	/* init process apertures*/
 	process->is_32bit_user_mode = in_compat_syscall();
 	err = kfd_init_apertures(process);
 	if (err != 0)
 		goto err_init_apertures;

 	err = kfd_process_init_cwsr(process, filep);
 	if (err)
 		goto err_init_cwsr;

 	return process;

 err_init_cwsr:
 	kfd_process_destroy_pdds(process);
 err_init_apertures:
 	pqm_uninit(&process->pqm);
 err_process_pqm_init:
 	hash_del_rcu(&process->kfd_processes);
 	synchronize_rcu();
 	mmu_notifier_unregister_no_release(&process->mmu_notifier, process->mm);
 err_mmu_notifier:
 	mutex_destroy(&process->mutex);
 	kfd_free_process_doorbells(process);
 err_alloc_doorbells:
 	kfd_pasid_free(process->pasid);
 err_alloc_pasid:
 	kfree(process);
 err_alloc_process:
 	return ERR_PTR(err);
 }

 struct kfd_process_device *kfd_get_process_device_data(struct kfd_dev *dev,
 							struct kfd_process *p)
 {
 	struct kfd_process_device *pdd = NULL;

 	list_for_each_entry(pdd, &p->per_device_data, per_device_list)
 		if (pdd->dev == dev)
 			return pdd;

 	return NULL;
 }

 struct kfd_process_device *kfd_create_process_device_data(struct kfd_dev *dev,
 							struct kfd_process *p)
 {
 	struct kfd_process_device *pdd = NULL;

 	pdd = kzalloc(sizeof(*pdd), GFP_KERNEL);
 	if (!pdd)
 		return NULL;

 	pdd->dev = dev;
 	INIT_LIST_HEAD(&pdd->qpd.queues_list);
 	INIT_LIST_HEAD(&pdd->qpd.priv_queue_list);
 	pdd->qpd.dqm = dev->dqm;
 	pdd->qpd.pqm = &p->pqm;
 	pdd->process = p;
 	pdd->bound = PDD_UNBOUND;
 	pdd->already_dequeued = false;
 	list_add(&pdd->per_device_list, &p->per_device_data);

 	return pdd;
 }

 /*
  * Direct the IOMMU to bind the process (specifically the pasid->mm)
  * to the device.
  * Unbinding occurs when the process dies or the device is removed.
  *
  * Assumes that the process lock is held.
  */
 struct kfd_process_device *kfd_bind_process_to_device(struct kfd_dev *dev,
 							struct kfd_process *p)
 {
 	struct kfd_process_device *pdd;
 	int err;

 	pdd = kfd_get_process_device_data(dev, p);
 	if (!pdd) {
 		pr_err("Process device data doesn't exist\n");
 		return ERR_PTR(-ENOMEM);
 	}

 	if (pdd->bound == PDD_BOUND) {
 		return pdd;
 	} else if (unlikely(pdd->bound == PDD_BOUND_SUSPENDED)) {
 		pr_err("Binding PDD_BOUND_SUSPENDED pdd is unexpected!\n");
 		return ERR_PTR(-EINVAL);
 	}

 	err = amd_iommu_bind_pasid(dev->pdev, p->pasid, p->lead_thread);
 	if (err < 0)
 		return ERR_PTR(err);

 	pdd->bound = PDD_BOUND;

 	return pdd;
 }

 /*
  * Bind processes do the device that have been temporarily unbound
  * (PDD_BOUND_SUSPENDED) in kfd_unbind_processes_from_device.
  */
 int kfd_bind_processes_to_device(struct kfd_dev *dev)
 {
 	struct kfd_process_device *pdd;
 	struct kfd_process *p;
 	unsigned int temp;
 	int err = 0;

 	int idx = srcu_read_lock(&kfd_processes_srcu);

 	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
 		mutex_lock(&p->mutex);
 		pdd = kfd_get_process_device_data(dev, p);

 		if (WARN_ON(!pdd) || pdd->bound != PDD_BOUND_SUSPENDED) {
 			mutex_unlock(&p->mutex);
 			continue;
 		}

 		err = amd_iommu_bind_pasid(dev->pdev, p->pasid,
 				p->lead_thread);
 		if (err < 0) {
 			pr_err("Unexpected pasid %d binding failure\n",
 					p->pasid);
 			mutex_unlock(&p->mutex);
 			break;
 		}

 		pdd->bound = PDD_BOUND;
 		mutex_unlock(&p->mutex);
 	}

 	srcu_read_unlock(&kfd_processes_srcu, idx);

 	return err;
 }

 /*
  * Mark currently bound processes as PDD_BOUND_SUSPENDED. These
  * processes will be restored to PDD_BOUND state in
  * kfd_bind_processes_to_device.
  */
 void kfd_unbind_processes_from_device(struct kfd_dev *dev)
 {
 	struct kfd_process_device *pdd;
 	struct kfd_process *p;
 	unsigned int temp;

 	int idx = srcu_read_lock(&kfd_processes_srcu);

 	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
 		mutex_lock(&p->mutex);
 		pdd = kfd_get_process_device_data(dev, p);

 		if (WARN_ON(!pdd)) {
 			mutex_unlock(&p->mutex);
 			continue;
 		}

 		if (pdd->bound == PDD_BOUND)
 			pdd->bound = PDD_BOUND_SUSPENDED;
 		mutex_unlock(&p->mutex);
 	}

 	srcu_read_unlock(&kfd_processes_srcu, idx);
 }

 void kfd_process_iommu_unbind_callback(struct kfd_dev *dev, unsigned int pasid)
 {
 	struct kfd_process *p;
 	struct kfd_process_device *pdd;

 	/*
 	 * Look for the process that matches the pasid. If there is no such
 	 * process, we either released it in amdkfd's own notifier, or there
 	 * is a bug. Unfortunately, there is no way to tell...
 	 */
 	p = kfd_lookup_process_by_pasid(pasid);
 	if (!p)
 		return;

 	pr_debug("Unbinding process %d from IOMMU\n", pasid);

 	mutex_lock(kfd_get_dbgmgr_mutex());

 	if (dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
 		if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
 			kfd_dbgmgr_destroy(dev->dbgmgr);
 			dev->dbgmgr = NULL;
 		}
 	}

 	mutex_unlock(kfd_get_dbgmgr_mutex());

 	mutex_lock(&p->mutex);

 	pdd = kfd_get_process_device_data(dev, p);
 	if (pdd)
 		/* For GPU relying on IOMMU, we need to dequeue here
 		 * when PASID is still bound.
 		 */
 		kfd_process_dequeue_from_device(pdd);

 	mutex_unlock(&p->mutex);

 	kfd_unref_process(p);
 }

 struct kfd_process_device *kfd_get_first_process_device_data(
 						struct kfd_process *p)
 {
 	return list_first_entry(&p->per_device_data,
 				struct kfd_process_device,
 				per_device_list);
 }

 struct kfd_process_device *kfd_get_next_process_device_data(
 						struct kfd_process *p,
 						struct kfd_process_device *pdd)
 {
 	if (list_is_last(&pdd->per_device_list, &p->per_device_data))
 		return NULL;
 	return list_next_entry(pdd, per_device_list);
 }

 bool kfd_has_process_device_data(struct kfd_process *p)
 {
 	return !(list_empty(&p->per_device_data));
 }

 /* This increments the process->ref counter. */
 struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid)
 {
 	struct kfd_process *p, *ret_p = NULL;
 	unsigned int temp;

 	int idx = srcu_read_lock(&kfd_processes_srcu);

 	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
 		if (p->pasid == pasid) {
 			kref_get(&p->ref);
 			ret_p = p;
 			break;
 		}
 	}

 	srcu_read_unlock(&kfd_processes_srcu, idx);

 	return ret_p;
 }

 int kfd_reserved_mem_mmap(struct kfd_process *process,
 			  struct vm_area_struct *vma)
 {
 	struct kfd_dev *dev = kfd_device_by_id(vma->vm_pgoff);
 	struct kfd_process_device *pdd;
 	struct qcm_process_device *qpd;

 	if (!dev)
 		return -EINVAL;
 	if ((vma->vm_end - vma->vm_start) != KFD_CWSR_TBA_TMA_SIZE) {
 		pr_err("Incorrect CWSR mapping size.\n");
 		return -EINVAL;
 	}

 	pdd = kfd_get_process_device_data(dev, process);
 	if (!pdd)
 		return -EINVAL;
 	qpd = &pdd->qpd;

 	qpd->cwsr_kaddr = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 					get_order(KFD_CWSR_TBA_TMA_SIZE));
 	if (!qpd->cwsr_kaddr) {
 		pr_err("Error allocating per process CWSR buffer.\n");
 		return -ENOMEM;
 	}

 	vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND
 		| VM_NORESERVE | VM_DONTDUMP | VM_PFNMAP;
 	/* Mapping pages to user process */
 	return remap_pfn_range(vma, vma->vm_start,
 			       PFN_DOWN(__pa(qpd->cwsr_kaddr)),
 			       KFD_CWSR_TBA_TMA_SIZE, vma->vm_page_prot);
 }

 #if defined(CONFIG_DEBUG_FS)

 int kfd_debugfs_mqds_by_process(struct seq_file *m, void *data)
 {
 	struct kfd_process *p;
 	unsigned int temp;
 	int r = 0;

 	int idx = srcu_read_lock(&kfd_processes_srcu);

 	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
 		seq_printf(m, "Process %d PASID %d:\n",
 			   p->lead_thread->tgid, p->pasid);

 		mutex_lock(&p->mutex);
 		r = pqm_debugfs_mqds(m, &p->pqm);
 		mutex_unlock(&p->mutex);

 		if (r)
 			break;
 	}

 	srcu_read_unlock(&kfd_processes_srcu, idx);

 	return r;
 }

 #endif
	/*
	* Copyright 2014 Advanced Micro Devices, Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*/

	#include <linux/mutex.h>
	#include <linux/log2.h>
	#include <linux/sched.h>
	#include <linux/sched/mm.h>
	#include <linux/sched/task.h>
	#include <linux/slab.h>
	#include <linux/amd-iommu.h>
	#include <linux/notifier.h>
	#include <linux/compat.h>
	#include <linux/mman.h>

	struct mm_struct;

	#include "kfd_priv.h"
	#include "kfd_dbgmgr.h"

	/*
	* List of struct kfd_process (field kfd_process).
	* Unique/indexed by mm_struct*
	*/
	#define KFD_PROCESS_TABLE_SIZE 5 /* bits: 32 entries */
	static DEFINE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
	static DEFINE_MUTEX(kfd_processes_mutex);

	DEFINE_STATIC_SRCU(kfd_processes_srcu);

	static struct workqueue_struct *kfd_process_wq;

	static struct kfd_process find_process(const struct task_struct thread);
	static void kfd_process_ref_release(struct kref *ref);
	static struct kfd_process create_process(const struct task_struct thread,
	struct file *filep);
	static int kfd_process_init_cwsr(struct kfd_process p, struct file filep);


	void kfd_process_create_wq(void)
	{
	if (!kfd_process_wq)
	kfd_process_wq = alloc_workqueue("kfd_process_wq", 0, 0);
	}

	void kfd_process_destroy_wq(void)
	{
	if (kfd_process_wq) {
	destroy_workqueue(kfd_process_wq);
	kfd_process_wq = NULL;
	}
	}

	struct kfd_process kfd_create_process(struct file filep)
	{
	struct kfd_process *process;
	struct task_struct *thread = current;

	if (!thread->mm)
	return ERR_PTR(-EINVAL);

	/* Only the pthreads threading model is supported. */
	if (thread->group_leader->mm != thread->mm)
	return ERR_PTR(-EINVAL);

	/*
	* take kfd processes mutex before starting of process creation
	* so there won't be a case where two threads of the same process
	* create two kfd_process structures
	*/
	mutex_lock(&kfd_processes_mutex);

	/* A prior open of /dev/kfd could have already created the process. */
	process = find_process(thread);
	if (process)
	pr_debug("Process already found\n");
	else
	process = create_process(thread, filep);

	mutex_unlock(&kfd_processes_mutex);

	return process;
	}

	struct kfd_process kfd_get_process(const struct task_struct thread)
	{
	struct kfd_process *process;

	if (!thread->mm)
	return ERR_PTR(-EINVAL);

	/* Only the pthreads threading model is supported. */
	if (thread->group_leader->mm != thread->mm)
	return ERR_PTR(-EINVAL);

	process = find_process(thread);

	return process;
	}

	static struct kfd_process find_process_by_mm(const struct mm_struct mm)
	{
	struct kfd_process *process;

	hash_for_each_possible_rcu(kfd_processes_table, process,
	kfd_processes, (uintptr_t)mm)
	if (process->mm == mm)
	return process;

	return NULL;
	}

	static struct kfd_process find_process(const struct task_struct thread)
	{
	struct kfd_process *p;
	int idx;

	idx = srcu_read_lock(&kfd_processes_srcu);
	p = find_process_by_mm(thread->mm);
	srcu_read_unlock(&kfd_processes_srcu, idx);

	return p;
	}

	void kfd_unref_process(struct kfd_process *p)
	{
	kref_put(&p->ref, kfd_process_ref_release);
	}

	static void kfd_process_destroy_pdds(struct kfd_process *p)
	{
	struct kfd_process_device pdd, temp;

	list_for_each_entry_safe(pdd, temp, &p->per_device_data,
	per_device_list) {
	pr_debug("Releasing pdd (topology id %d) for process (pasid %d)\n",
	pdd->dev->id, p->pasid);

	list_del(&pdd->per_device_list);

	if (pdd->qpd.cwsr_kaddr)
	free_pages((unsigned long)pdd->qpd.cwsr_kaddr,
	get_order(KFD_CWSR_TBA_TMA_SIZE));

	kfree(pdd);
	}
	}

	/* No process locking is needed in this function, because the process
	* is not findable any more. We must assume that no other thread is
	* using it any more, otherwise we couldn't safely free the process
	* structure in the end.
	*/
	static void kfd_process_wq_release(struct work_struct *work)
	{
	struct kfd_process *p = container_of(work, struct kfd_process,
	release_work);
	struct kfd_process_device *pdd;

	pr_debug("Releasing process (pasid %d) in workqueue\n", p->pasid);

	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
	if (pdd->bound == PDD_BOUND)
	amd_iommu_unbind_pasid(pdd->dev->pdev, p->pasid);
	}

	kfd_process_destroy_pdds(p);

	kfd_event_free_process(p);

	kfd_pasid_free(p->pasid);
	kfd_free_process_doorbells(p);

	mutex_destroy(&p->mutex);

	put_task_struct(p->lead_thread);

	kfree(p);
	}

	static void kfd_process_ref_release(struct kref *ref)
	{
	struct kfd_process *p = container_of(ref, struct kfd_process, ref);

	INIT_WORK(&p->release_work, kfd_process_wq_release);
	queue_work(kfd_process_wq, &p->release_work);
	}

	static void kfd_process_destroy_delayed(struct rcu_head *rcu)
	{
	struct kfd_process *p = container_of(rcu, struct kfd_process, rcu);

	kfd_unref_process(p);
	}

	static void kfd_process_notifier_release(struct mmu_notifier *mn,
	struct mm_struct *mm)
	{
	struct kfd_process *p;
	struct kfd_process_device *pdd = NULL;

	/*
	* The kfd_process structure can not be free because the
	* mmu_notifier srcu is read locked
	*/
	p = container_of(mn, struct kfd_process, mmu_notifier);
	if (WARN_ON(p->mm != mm))
	return;

	mutex_lock(&kfd_processes_mutex);
	hash_del_rcu(&p->kfd_processes);
	mutex_unlock(&kfd_processes_mutex);
	synchronize_srcu(&kfd_processes_srcu);

	mutex_lock(&p->mutex);

	/* Iterate over all process device data structures and if the
	* pdd is in debug mode, we should first force unregistration,
	* then we will be able to destroy the queues
	*/
	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
	struct kfd_dev *dev = pdd->dev;

	mutex_lock(kfd_get_dbgmgr_mutex());
	if (dev && dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
	if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
	kfd_dbgmgr_destroy(dev->dbgmgr);
	dev->dbgmgr = NULL;
	}
	}
	mutex_unlock(kfd_get_dbgmgr_mutex());
	}

	kfd_process_dequeue_from_all_devices(p);
	pqm_uninit(&p->pqm);

	/* Indicate to other users that MM is no longer valid */
	p->mm = NULL;

	mutex_unlock(&p->mutex);

	mmu_notifier_unregister_no_release(&p->mmu_notifier, mm);
	mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
	}

	static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
	.release = kfd_process_notifier_release,
	};

	static int kfd_process_init_cwsr(struct kfd_process p, struct file filep)
	{
	unsigned long offset;
	struct kfd_process_device *pdd = NULL;
	struct kfd_dev *dev = NULL;
	struct qcm_process_device *qpd = NULL;

	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
	dev = pdd->dev;
	qpd = &pdd->qpd;
	if (!dev->cwsr_enabled \|\| qpd->cwsr_kaddr)
	continue;
	offset = (dev->id \| KFD_MMAP_RESERVED_MEM_MASK) << PAGE_SHIFT;
	qpd->tba_addr = (int64_t)vm_mmap(filep, 0,
	KFD_CWSR_TBA_TMA_SIZE, PROT_READ \| PROT_EXEC,
	MAP_SHARED, offset);

	if (IS_ERR_VALUE(qpd->tba_addr)) {
	int err = qpd->tba_addr;

	pr_err("Failure to set tba address. error %d.\n", err);
	qpd->tba_addr = 0;
	qpd->cwsr_kaddr = NULL;
	return err;
	}

	memcpy(qpd->cwsr_kaddr, dev->cwsr_isa, dev->cwsr_isa_size);

	qpd->tma_addr = qpd->tba_addr + KFD_CWSR_TMA_OFFSET;
	pr_debug("set tba :0x%llx, tma:0x%llx, cwsr_kaddr:%p for pqm.\n",
	qpd->tba_addr, qpd->tma_addr, qpd->cwsr_kaddr);
	}

	return 0;
	}

	static struct kfd_process create_process(const struct task_struct thread,
	struct file *filep)
	{
	struct kfd_process *process;
	int err = -ENOMEM;

	process = kzalloc(sizeof(*process), GFP_KERNEL);

	if (!process)
	goto err_alloc_process;

	process->pasid = kfd_pasid_alloc();
	if (process->pasid == 0)
	goto err_alloc_pasid;

	if (kfd_alloc_process_doorbells(process) < 0)
	goto err_alloc_doorbells;

	kref_init(&process->ref);

	mutex_init(&process->mutex);

	process->mm = thread->mm;

	/* register notifier */
	process->mmu_notifier.ops = &kfd_process_mmu_notifier_ops;
	err = mmu_notifier_register(&process->mmu_notifier, process->mm);
	if (err)
	goto err_mmu_notifier;

	hash_add_rcu(kfd_processes_table, &process->kfd_processes,
	(uintptr_t)process->mm);

	process->lead_thread = thread->group_leader;
	get_task_struct(process->lead_thread);

	INIT_LIST_HEAD(&process->per_device_data);

	kfd_event_init_process(process);

	err = pqm_init(&process->pqm, process);
	if (err != 0)
	goto err_process_pqm_init;

	/* init process apertures*/
	process->is_32bit_user_mode = in_compat_syscall();
	err = kfd_init_apertures(process);
	if (err != 0)
	goto err_init_apertures;

	err = kfd_process_init_cwsr(process, filep);
	if (err)
	goto err_init_cwsr;

	return process;

	err_init_cwsr:
	kfd_process_destroy_pdds(process);
	err_init_apertures:
	pqm_uninit(&process->pqm);
	err_process_pqm_init:
	hash_del_rcu(&process->kfd_processes);
	synchronize_rcu();
	mmu_notifier_unregister_no_release(&process->mmu_notifier, process->mm);
	err_mmu_notifier:
	mutex_destroy(&process->mutex);
	kfd_free_process_doorbells(process);
	err_alloc_doorbells:
	kfd_pasid_free(process->pasid);
	err_alloc_pasid:
	kfree(process);
	err_alloc_process:
	return ERR_PTR(err);
	}

	struct kfd_process_device kfd_get_process_device_data(struct kfd_dev dev,
	struct kfd_process *p)
	{
	struct kfd_process_device *pdd = NULL;

	list_for_each_entry(pdd, &p->per_device_data, per_device_list)
	if (pdd->dev == dev)
	return pdd;

	return NULL;
	}

	struct kfd_process_device kfd_create_process_device_data(struct kfd_dev dev,
	struct kfd_process *p)
	{
	struct kfd_process_device *pdd = NULL;

	pdd = kzalloc(sizeof(*pdd), GFP_KERNEL);
	if (!pdd)
	return NULL;

	pdd->dev = dev;
	INIT_LIST_HEAD(&pdd->qpd.queues_list);
	INIT_LIST_HEAD(&pdd->qpd.priv_queue_list);
	pdd->qpd.dqm = dev->dqm;
	pdd->qpd.pqm = &p->pqm;
	pdd->process = p;
	pdd->bound = PDD_UNBOUND;
	pdd->already_dequeued = false;
	list_add(&pdd->per_device_list, &p->per_device_data);

	return pdd;
	}

	/*
	* Direct the IOMMU to bind the process (specifically the pasid->mm)
	* to the device.
	* Unbinding occurs when the process dies or the device is removed.
	*
	* Assumes that the process lock is held.
	*/
	struct kfd_process_device kfd_bind_process_to_device(struct kfd_dev dev,
	struct kfd_process *p)
	{
	struct kfd_process_device *pdd;
	int err;

	pdd = kfd_get_process_device_data(dev, p);
	if (!pdd) {
	pr_err("Process device data doesn't exist\n");
	return ERR_PTR(-ENOMEM);
	}

	if (pdd->bound == PDD_BOUND) {
	return pdd;
	} else if (unlikely(pdd->bound == PDD_BOUND_SUSPENDED)) {
	pr_err("Binding PDD_BOUND_SUSPENDED pdd is unexpected!\n");
	return ERR_PTR(-EINVAL);
	}

	err = amd_iommu_bind_pasid(dev->pdev, p->pasid, p->lead_thread);
	if (err < 0)
	return ERR_PTR(err);

	pdd->bound = PDD_BOUND;

	return pdd;
	}

	/*
	* Bind processes do the device that have been temporarily unbound
	* (PDD_BOUND_SUSPENDED) in kfd_unbind_processes_from_device.
	*/
	int kfd_bind_processes_to_device(struct kfd_dev *dev)
	{
	struct kfd_process_device *pdd;
	struct kfd_process *p;
	unsigned int temp;
	int err = 0;

	int idx = srcu_read_lock(&kfd_processes_srcu);

	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
	mutex_lock(&p->mutex);
	pdd = kfd_get_process_device_data(dev, p);

	if (WARN_ON(!pdd) \|\| pdd->bound != PDD_BOUND_SUSPENDED) {
	mutex_unlock(&p->mutex);
	continue;
	}

	err = amd_iommu_bind_pasid(dev->pdev, p->pasid,
	p->lead_thread);
	if (err < 0) {
	pr_err("Unexpected pasid %d binding failure\n",
	p->pasid);
	mutex_unlock(&p->mutex);
	break;
	}

	pdd->bound = PDD_BOUND;
	mutex_unlock(&p->mutex);
	}

	srcu_read_unlock(&kfd_processes_srcu, idx);

	return err;
	}

	/*
	* Mark currently bound processes as PDD_BOUND_SUSPENDED. These
	* processes will be restored to PDD_BOUND state in
	* kfd_bind_processes_to_device.
	*/
	void kfd_unbind_processes_from_device(struct kfd_dev *dev)
	{
	struct kfd_process_device *pdd;
	struct kfd_process *p;
	unsigned int temp;

	int idx = srcu_read_lock(&kfd_processes_srcu);

	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
	mutex_lock(&p->mutex);
	pdd = kfd_get_process_device_data(dev, p);

	if (WARN_ON(!pdd)) {
	mutex_unlock(&p->mutex);
	continue;
	}

	if (pdd->bound == PDD_BOUND)
	pdd->bound = PDD_BOUND_SUSPENDED;
	mutex_unlock(&p->mutex);
	}

	srcu_read_unlock(&kfd_processes_srcu, idx);
	}

	void kfd_process_iommu_unbind_callback(struct kfd_dev *dev, unsigned int pasid)
	{
	struct kfd_process *p;
	struct kfd_process_device *pdd;

	/*
	* Look for the process that matches the pasid. If there is no such
	* process, we either released it in amdkfd's own notifier, or there
	* is a bug. Unfortunately, there is no way to tell...
	*/
	p = kfd_lookup_process_by_pasid(pasid);
	if (!p)
	return;

	pr_debug("Unbinding process %d from IOMMU\n", pasid);

	mutex_lock(kfd_get_dbgmgr_mutex());

	if (dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
	if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
	kfd_dbgmgr_destroy(dev->dbgmgr);
	dev->dbgmgr = NULL;
	}
	}

	mutex_unlock(kfd_get_dbgmgr_mutex());

	mutex_lock(&p->mutex);

	pdd = kfd_get_process_device_data(dev, p);
	if (pdd)
	/* For GPU relying on IOMMU, we need to dequeue here
	* when PASID is still bound.
	*/
	kfd_process_dequeue_from_device(pdd);

	mutex_unlock(&p->mutex);

	kfd_unref_process(p);
	}

	struct kfd_process_device *kfd_get_first_process_device_data(
	struct kfd_process *p)
	{
	return list_first_entry(&p->per_device_data,
	struct kfd_process_device,
	per_device_list);
	}

	struct kfd_process_device *kfd_get_next_process_device_data(
	struct kfd_process *p,
	struct kfd_process_device *pdd)
	{
	if (list_is_last(&pdd->per_device_list, &p->per_device_data))
	return NULL;
	return list_next_entry(pdd, per_device_list);
	}

	bool kfd_has_process_device_data(struct kfd_process *p)
	{
	return !(list_empty(&p->per_device_data));
	}

	/* This increments the process->ref counter. */
	struct kfd_process *kfd_lookup_process_by_pasid(unsigned int pasid)
	{
	struct kfd_process p, ret_p = NULL;
	unsigned int temp;

	int idx = srcu_read_lock(&kfd_processes_srcu);

	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
	if (p->pasid == pasid) {
	kref_get(&p->ref);
	ret_p = p;
	break;
	}
	}

	srcu_read_unlock(&kfd_processes_srcu, idx);

	return ret_p;
	}

	int kfd_reserved_mem_mmap(struct kfd_process *process,
	struct vm_area_struct *vma)
	{
	struct kfd_dev *dev = kfd_device_by_id(vma->vm_pgoff);
	struct kfd_process_device *pdd;
	struct qcm_process_device *qpd;

	if (!dev)
	return -EINVAL;
	if ((vma->vm_end - vma->vm_start) != KFD_CWSR_TBA_TMA_SIZE) {
	pr_err("Incorrect CWSR mapping size.\n");
	return -EINVAL;
	}

	pdd = kfd_get_process_device_data(dev, process);
	if (!pdd)
	return -EINVAL;
	qpd = &pdd->qpd;

	qpd->cwsr_kaddr = (void *)__get_free_pages(GFP_KERNEL \| __GFP_ZERO,
	get_order(KFD_CWSR_TBA_TMA_SIZE));
	if (!qpd->cwsr_kaddr) {
	pr_err("Error allocating per process CWSR buffer.\n");
	return -ENOMEM;
	}

	vma->vm_flags \|= VM_IO \| VM_DONTCOPY \| VM_DONTEXPAND
	\| VM_NORESERVE \| VM_DONTDUMP \| VM_PFNMAP;
	/* Mapping pages to user process */
	return remap_pfn_range(vma, vma->vm_start,
	PFN_DOWN(__pa(qpd->cwsr_kaddr)),
	KFD_CWSR_TBA_TMA_SIZE, vma->vm_page_prot);
	}

	#if defined(CONFIG_DEBUG_FS)

	int kfd_debugfs_mqds_by_process(struct seq_file m, void data)
	{
	struct kfd_process *p;
	unsigned int temp;
	int r = 0;

	int idx = srcu_read_lock(&kfd_processes_srcu);

	hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
	seq_printf(m, "Process %d PASID %d:\n",
	p->lead_thread->tgid, p->pasid);

	mutex_lock(&p->mutex);
	r = pqm_debugfs_mqds(m, &p->pqm);
	mutex_unlock(&p->mutex);

	if (r)
	break;
	}

	srcu_read_unlock(&kfd_processes_srcu, idx);

	return r;
	}

	#endif