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1/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */
2
3/* Much of this ripped from drivers/char/hw_random.c, see there for other
4 * copyright.
5 *
6 * This software may be used and distributed according to the terms
7 * of the GNU General Public License, incorporated herein by reference.
8 */
9#include <linux/sched/signal.h>
10#include <linux/module.h>
11#include <linux/fs.h>
12#include <linux/interrupt.h>
13#include <linux/miscdevice.h>
14#include <linux/hw_random.h>
15#include <linux/delay.h>
16#include <linux/uaccess.h>
17#include <init.h>
18#include <irq_kern.h>
19#include <os.h>
20
21/*
22 * core module information
23 */
24#define RNG_MODULE_NAME "hw_random"
25
26/* Changed at init time, in the non-modular case, and at module load
27 * time, in the module case. Presumably, the module subsystem
28 * protects against a module being loaded twice at the same time.
29 */
30static int random_fd = -1;
31static struct hwrng hwrng;
32static DECLARE_COMPLETION(have_data);
33
34static int rng_dev_read(struct hwrng *rng, void *buf, size_t max, bool block)
35{
36 int ret;
37
38 for (;;) {
39 ret = os_read_file(random_fd, buf, max);
40 if (block && ret == -EAGAIN) {
41 add_sigio_fd(random_fd);
42
43 ret = wait_for_completion_killable(&have_data);
44
45 ignore_sigio_fd(random_fd);
46 deactivate_fd(random_fd, RANDOM_IRQ);
47
48 if (ret < 0)
49 break;
50 } else {
51 break;
52 }
53 }
54
55 return ret != -EAGAIN ? ret : 0;
56}
57
58static irqreturn_t random_interrupt(int irq, void *data)
59{
60 complete(&have_data);
61
62 return IRQ_HANDLED;
63}
64
65/*
66 * rng_init - initialize RNG module
67 */
68static int __init rng_init (void)
69{
70 int err;
71
72 err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0);
73 if (err < 0)
74 goto out;
75
76 random_fd = err;
77 err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
78 0, "random", NULL);
79 if (err < 0)
80 goto err_out_cleanup_hw;
81
82 sigio_broken(random_fd);
83 hwrng.name = RNG_MODULE_NAME;
84 hwrng.read = rng_dev_read;
85
86 err = hwrng_register(&hwrng);
87 if (err) {
88 pr_err(RNG_MODULE_NAME " registering failed (%d)\n", err);
89 goto err_out_cleanup_hw;
90 }
91out:
92 return err;
93
94err_out_cleanup_hw:
95 os_close_file(random_fd);
96 random_fd = -1;
97 goto out;
98}
99
100/*
101 * rng_cleanup - shutdown RNG module
102 */
103
104static void cleanup(void)
105{
106 free_irq_by_fd(random_fd);
107 os_close_file(random_fd);
108}
109
110static void __exit rng_cleanup(void)
111{
112 hwrng_unregister(&hwrng);
113 os_close_file(random_fd);
114}
115
116module_init (rng_init);
117module_exit (rng_cleanup);
118__uml_exitcall(cleanup);
119
120MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
121MODULE_LICENSE("GPL");
1/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */
2
3/* Much of this ripped from drivers/char/hw_random.c, see there for other
4 * copyright.
5 *
6 * This software may be used and distributed according to the terms
7 * of the GNU General Public License, incorporated herein by reference.
8 */
9#include <linux/sched/signal.h>
10#include <linux/module.h>
11#include <linux/fs.h>
12#include <linux/interrupt.h>
13#include <linux/miscdevice.h>
14#include <linux/delay.h>
15#include <linux/uaccess.h>
16#include <init.h>
17#include <irq_kern.h>
18#include <os.h>
19
20/*
21 * core module and version information
22 */
23#define RNG_VERSION "1.0.0"
24#define RNG_MODULE_NAME "hw_random"
25
26#define RNG_MISCDEV_MINOR 183 /* official */
27
28/* Changed at init time, in the non-modular case, and at module load
29 * time, in the module case. Presumably, the module subsystem
30 * protects against a module being loaded twice at the same time.
31 */
32static int random_fd = -1;
33static DECLARE_WAIT_QUEUE_HEAD(host_read_wait);
34
35static int rng_dev_open (struct inode *inode, struct file *filp)
36{
37 /* enforce read-only access to this chrdev */
38 if ((filp->f_mode & FMODE_READ) == 0)
39 return -EINVAL;
40 if ((filp->f_mode & FMODE_WRITE) != 0)
41 return -EINVAL;
42
43 return 0;
44}
45
46static atomic_t host_sleep_count = ATOMIC_INIT(0);
47
48static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
49 loff_t *offp)
50{
51 u32 data;
52 int n, ret = 0, have_data;
53
54 while (size) {
55 n = os_read_file(random_fd, &data, sizeof(data));
56 if (n > 0) {
57 have_data = n;
58 while (have_data && size) {
59 if (put_user((u8) data, buf++)) {
60 ret = ret ? : -EFAULT;
61 break;
62 }
63 size--;
64 ret++;
65 have_data--;
66 data >>= 8;
67 }
68 }
69 else if (n == -EAGAIN) {
70 DECLARE_WAITQUEUE(wait, current);
71
72 if (filp->f_flags & O_NONBLOCK)
73 return ret ? : -EAGAIN;
74
75 atomic_inc(&host_sleep_count);
76 reactivate_fd(random_fd, RANDOM_IRQ);
77 add_sigio_fd(random_fd);
78
79 add_wait_queue(&host_read_wait, &wait);
80 set_current_state(TASK_INTERRUPTIBLE);
81
82 schedule();
83 remove_wait_queue(&host_read_wait, &wait);
84
85 if (atomic_dec_and_test(&host_sleep_count)) {
86 ignore_sigio_fd(random_fd);
87 deactivate_fd(random_fd, RANDOM_IRQ);
88 }
89 }
90 else
91 return n;
92
93 if (signal_pending (current))
94 return ret ? : -ERESTARTSYS;
95 }
96 return ret;
97}
98
99static const struct file_operations rng_chrdev_ops = {
100 .owner = THIS_MODULE,
101 .open = rng_dev_open,
102 .read = rng_dev_read,
103 .llseek = noop_llseek,
104};
105
106/* rng_init shouldn't be called more than once at boot time */
107static struct miscdevice rng_miscdev = {
108 RNG_MISCDEV_MINOR,
109 RNG_MODULE_NAME,
110 &rng_chrdev_ops,
111};
112
113static irqreturn_t random_interrupt(int irq, void *data)
114{
115 wake_up(&host_read_wait);
116
117 return IRQ_HANDLED;
118}
119
120/*
121 * rng_init - initialize RNG module
122 */
123static int __init rng_init (void)
124{
125 int err;
126
127 err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0);
128 if (err < 0)
129 goto out;
130
131 random_fd = err;
132
133 err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
134 0, "random", NULL);
135 if (err)
136 goto err_out_cleanup_hw;
137
138 sigio_broken(random_fd, 1);
139
140 err = misc_register (&rng_miscdev);
141 if (err) {
142 printk (KERN_ERR RNG_MODULE_NAME ": misc device register "
143 "failed\n");
144 goto err_out_cleanup_hw;
145 }
146out:
147 return err;
148
149err_out_cleanup_hw:
150 os_close_file(random_fd);
151 random_fd = -1;
152 goto out;
153}
154
155/*
156 * rng_cleanup - shutdown RNG module
157 */
158
159static void cleanup(void)
160{
161 free_irq_by_fd(random_fd);
162 os_close_file(random_fd);
163}
164
165static void __exit rng_cleanup(void)
166{
167 os_close_file(random_fd);
168 misc_deregister (&rng_miscdev);
169}
170
171module_init (rng_init);
172module_exit (rng_cleanup);
173__uml_exitcall(cleanup);
174
175MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
176MODULE_LICENSE("GPL");