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