1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2015-2021, Linaro Limited
4 */
5
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8 #include <linux/arm-smccc.h>
9 #include <linux/errno.h>
10 #include <linux/slab.h>
11 #include <linux/spinlock.h>
12 #include <linux/tee_drv.h>
13 #include "optee_private.h"
14
15 struct notif_entry {
16 struct list_head link;
17 struct completion c;
18 u_int key;
19 };
20
have_key(struct optee * optee,u_int key)21 static bool have_key(struct optee *optee, u_int key)
22 {
23 struct notif_entry *entry;
24
25 list_for_each_entry(entry, &optee->notif.db, link)
26 if (entry->key == key)
27 return true;
28
29 return false;
30 }
31
optee_notif_wait(struct optee * optee,u_int key)32 int optee_notif_wait(struct optee *optee, u_int key)
33 {
34 unsigned long flags;
35 struct notif_entry *entry;
36 int rc = 0;
37
38 if (key > optee->notif.max_key)
39 return -EINVAL;
40
41 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
42 if (!entry)
43 return -ENOMEM;
44 init_completion(&entry->c);
45 entry->key = key;
46
47 spin_lock_irqsave(&optee->notif.lock, flags);
48
49 /*
50 * If the bit is already set it means that the key has already
51 * been posted and we must not wait.
52 */
53 if (test_bit(key, optee->notif.bitmap)) {
54 clear_bit(key, optee->notif.bitmap);
55 goto out;
56 }
57
58 /*
59 * Check if someone is already waiting for this key. If there is
60 * it's a programming error.
61 */
62 if (have_key(optee, key)) {
63 rc = -EBUSY;
64 goto out;
65 }
66
67 list_add_tail(&entry->link, &optee->notif.db);
68
69 /*
70 * Unlock temporarily and wait for completion.
71 */
72 spin_unlock_irqrestore(&optee->notif.lock, flags);
73 wait_for_completion(&entry->c);
74 spin_lock_irqsave(&optee->notif.lock, flags);
75
76 list_del(&entry->link);
77 out:
78 spin_unlock_irqrestore(&optee->notif.lock, flags);
79
80 kfree(entry);
81
82 return rc;
83 }
84
optee_notif_send(struct optee * optee,u_int key)85 int optee_notif_send(struct optee *optee, u_int key)
86 {
87 unsigned long flags;
88 struct notif_entry *entry;
89
90 if (key > optee->notif.max_key)
91 return -EINVAL;
92
93 spin_lock_irqsave(&optee->notif.lock, flags);
94
95 list_for_each_entry(entry, &optee->notif.db, link)
96 if (entry->key == key) {
97 complete(&entry->c);
98 goto out;
99 }
100
101 /* Only set the bit in case there where nobody waiting */
102 set_bit(key, optee->notif.bitmap);
103 out:
104 spin_unlock_irqrestore(&optee->notif.lock, flags);
105
106 return 0;
107 }
108
optee_notif_init(struct optee * optee,u_int max_key)109 int optee_notif_init(struct optee *optee, u_int max_key)
110 {
111 spin_lock_init(&optee->notif.lock);
112 INIT_LIST_HEAD(&optee->notif.db);
113 optee->notif.bitmap = bitmap_zalloc(max_key, GFP_KERNEL);
114 if (!optee->notif.bitmap)
115 return -ENOMEM;
116
117 optee->notif.max_key = max_key;
118
119 return 0;
120 }
121
optee_notif_uninit(struct optee * optee)122 void optee_notif_uninit(struct optee *optee)
123 {
124 bitmap_free(optee->notif.bitmap);
125 }
126