mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 13:46:39 +07:00
37185b3324
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
169 lines
3.6 KiB
C
169 lines
3.6 KiB
C
/* 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.h>
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/delay.h>
|
|
#include <asm/uaccess.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_task_state(current, TASK_INTERRUPTIBLE);
|
|
|
|
schedule();
|
|
set_task_state(current, TASK_RUNNING);
|
|
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 __exit rng_cleanup (void)
|
|
{
|
|
os_close_file(random_fd);
|
|
misc_deregister (&rng_miscdev);
|
|
}
|
|
|
|
module_init (rng_init);
|
|
module_exit (rng_cleanup);
|
|
|
|
MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
|
|
MODULE_LICENSE("GPL");
|