1 /*
2 * Copyright (c) 2019 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34 #include <sys/cdefs.h>
35
36 #include <sys/condvar.h>
37 #include <sys/queue.h>
38 #include <sys/lock.h>
39
40 #include <linux/compiler.h>
41
42 #include <linux/atomic.h>
43 #include <linux/errno.h>
44 #include <linux/kref.h>
45 #include <linux/dma-fence.h>
46 #include <linux/sched.h>
47 #include <linux/slab.h>
48 #include <linux/spinlock.h>
49
50 /*
51 * Called when curthread->td_linux_task is NULL. We must allocated, initialize,
52 * and install a task_struct in td (the current thread).
53 *
54 * All threads belonging to the same process have a common mm_struct which
55 * is stored as p->p_linux_mm. This must be allocated, initialized, and
56 * and installed if necessary.
57 */
58 struct task_struct *
linux_task_alloc(struct thread * td)59 linux_task_alloc(struct thread *td)
60 {
61 struct task_struct *task;
62 struct mm_struct *mm;
63 struct proc *p;
64
65 task = kzalloc(sizeof(*task), GFP_KERNEL);
66 task->dfly_td = td;
67 task->pid = -1;
68 spin_init(&task->kt_spin, "tspin2");
69
70 if ((p = td->td_proc) != NULL) {
71 task->pid = td->td_proc->p_pid;
72 if ((mm = p->p_linux_mm) == NULL) {
73 mm = kzalloc(sizeof(*mm), GFP_KERNEL);
74 mm->refs = 1;
75 lockinit(&mm->mmap_sem, "drmmms", 0, LK_CANRECURSE);
76 lwkt_gettoken(&p->p_token);
77 if (p->p_linux_mm == NULL) {
78 p->p_linux_mm = mm;
79 } else {
80 linux_mm_drop(mm);
81 mm = p->p_linux_mm;
82 }
83 lwkt_reltoken(&p->p_token);
84 }
85 task->mm = mm;
86 atomic_add_long(&mm->refs, 1);
87 }
88 td->td_linux_task = task;
89
90 return task;
91 }
92
93 /*
94 * Called at thread exit
95 */
96 void
linux_task_drop(struct thread * td)97 linux_task_drop(struct thread *td)
98 {
99 struct task_struct *task;
100 struct mm_struct *mm;
101
102 task = td->td_linux_task;
103 td->td_linux_task = NULL;
104 if ((mm = task->mm) != NULL) {
105 atomic_add_long(&mm->refs, -1); /* proc ref always remains */
106 task->mm = NULL;
107 }
108 kfree(task);
109 }
110
111 void
linux_proc_drop(struct proc * p)112 linux_proc_drop(struct proc *p)
113 {
114 struct mm_struct *mm;
115
116 if ((mm = p->p_linux_mm) != NULL) {
117 p->p_linux_mm = NULL;
118 linux_mm_drop(mm);
119 }
120 }
121
122 void
linux_mm_drop(struct mm_struct * mm)123 linux_mm_drop(struct mm_struct *mm)
124 {
125 long refs;
126
127 refs = atomic_fetchadd_long(&mm->refs, -1);
128 KKASSERT(refs > 0);
129 if (refs == 1) {
130 lockuninit(&mm->mmap_sem);
131 kfree(mm);
132 }
133 }
134