mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
a9c4e8f74b
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
350 lines
7.2 KiB
C
350 lines
7.2 KiB
C
/*
|
|
Added support for the AMD Geode LX RNG
|
|
(c) Copyright 2004-2005 Advanced Micro Devices, Inc.
|
|
|
|
derived from
|
|
|
|
Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
|
|
(c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
|
|
|
|
derived from
|
|
|
|
Hardware driver for the AMD 768 Random Number Generator (RNG)
|
|
(c) Copyright 2001 Red Hat Inc <alan@redhat.com>
|
|
|
|
derived from
|
|
|
|
Hardware driver for Intel i810 Random Number Generator (RNG)
|
|
Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
|
|
Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
|
|
|
|
Added generic RNG API
|
|
Copyright 2006 Michael Buesch <mbuesch@freenet.de>
|
|
Copyright 2005 (c) MontaVista Software, Inc.
|
|
|
|
Please read Documentation/hw_random.txt for details on use.
|
|
|
|
----------------------------------------------------------
|
|
This software may be used and distributed according to the terms
|
|
of the GNU General Public License, incorporated herein by reference.
|
|
|
|
*/
|
|
|
|
|
|
#include <linux/device.h>
|
|
#include <linux/hw_random.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/init.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/delay.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
|
|
#define RNG_MODULE_NAME "hw_random"
|
|
#define PFX RNG_MODULE_NAME ": "
|
|
#define RNG_MISCDEV_MINOR 183 /* official */
|
|
|
|
|
|
static struct hwrng *current_rng;
|
|
static LIST_HEAD(rng_list);
|
|
static DEFINE_MUTEX(rng_mutex);
|
|
|
|
|
|
static inline int hwrng_init(struct hwrng *rng)
|
|
{
|
|
if (!rng->init)
|
|
return 0;
|
|
return rng->init(rng);
|
|
}
|
|
|
|
static inline void hwrng_cleanup(struct hwrng *rng)
|
|
{
|
|
if (rng && rng->cleanup)
|
|
rng->cleanup(rng);
|
|
}
|
|
|
|
static inline int hwrng_data_present(struct hwrng *rng, int wait)
|
|
{
|
|
if (!rng->data_present)
|
|
return 1;
|
|
return rng->data_present(rng, wait);
|
|
}
|
|
|
|
static inline int hwrng_data_read(struct hwrng *rng, u32 *data)
|
|
{
|
|
return rng->data_read(rng, data);
|
|
}
|
|
|
|
|
|
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)
|
|
return -EINVAL;
|
|
cycle_kernel_lock();
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t rng_dev_read(struct file *filp, char __user *buf,
|
|
size_t size, loff_t *offp)
|
|
{
|
|
u32 data;
|
|
ssize_t ret = 0;
|
|
int err = 0;
|
|
int bytes_read;
|
|
|
|
while (size) {
|
|
err = -ERESTARTSYS;
|
|
if (mutex_lock_interruptible(&rng_mutex))
|
|
goto out;
|
|
if (!current_rng) {
|
|
mutex_unlock(&rng_mutex);
|
|
err = -ENODEV;
|
|
goto out;
|
|
}
|
|
|
|
bytes_read = 0;
|
|
if (hwrng_data_present(current_rng,
|
|
!(filp->f_flags & O_NONBLOCK)))
|
|
bytes_read = hwrng_data_read(current_rng, &data);
|
|
mutex_unlock(&rng_mutex);
|
|
|
|
err = -EAGAIN;
|
|
if (!bytes_read && (filp->f_flags & O_NONBLOCK))
|
|
goto out;
|
|
if (bytes_read < 0) {
|
|
err = bytes_read;
|
|
goto out;
|
|
}
|
|
|
|
err = -EFAULT;
|
|
while (bytes_read && size) {
|
|
if (put_user((u8)data, buf++))
|
|
goto out;
|
|
size--;
|
|
ret++;
|
|
bytes_read--;
|
|
data >>= 8;
|
|
}
|
|
|
|
if (need_resched())
|
|
schedule_timeout_interruptible(1);
|
|
err = -ERESTARTSYS;
|
|
if (signal_pending(current))
|
|
goto out;
|
|
}
|
|
out:
|
|
return ret ? : err;
|
|
}
|
|
|
|
|
|
static const struct file_operations rng_chrdev_ops = {
|
|
.owner = THIS_MODULE,
|
|
.open = rng_dev_open,
|
|
.read = rng_dev_read,
|
|
};
|
|
|
|
static struct miscdevice rng_miscdev = {
|
|
.minor = RNG_MISCDEV_MINOR,
|
|
.name = RNG_MODULE_NAME,
|
|
.fops = &rng_chrdev_ops,
|
|
};
|
|
|
|
|
|
static ssize_t hwrng_attr_current_store(struct device *dev,
|
|
struct device_attribute *attr,
|
|
const char *buf, size_t len)
|
|
{
|
|
int err;
|
|
struct hwrng *rng;
|
|
|
|
err = mutex_lock_interruptible(&rng_mutex);
|
|
if (err)
|
|
return -ERESTARTSYS;
|
|
err = -ENODEV;
|
|
list_for_each_entry(rng, &rng_list, list) {
|
|
if (strcmp(rng->name, buf) == 0) {
|
|
if (rng == current_rng) {
|
|
err = 0;
|
|
break;
|
|
}
|
|
err = hwrng_init(rng);
|
|
if (err)
|
|
break;
|
|
hwrng_cleanup(current_rng);
|
|
current_rng = rng;
|
|
err = 0;
|
|
break;
|
|
}
|
|
}
|
|
mutex_unlock(&rng_mutex);
|
|
|
|
return err ? : len;
|
|
}
|
|
|
|
static ssize_t hwrng_attr_current_show(struct device *dev,
|
|
struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
int err;
|
|
ssize_t ret;
|
|
const char *name = "none";
|
|
|
|
err = mutex_lock_interruptible(&rng_mutex);
|
|
if (err)
|
|
return -ERESTARTSYS;
|
|
if (current_rng)
|
|
name = current_rng->name;
|
|
ret = snprintf(buf, PAGE_SIZE, "%s\n", name);
|
|
mutex_unlock(&rng_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t hwrng_attr_available_show(struct device *dev,
|
|
struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
int err;
|
|
ssize_t ret = 0;
|
|
struct hwrng *rng;
|
|
|
|
err = mutex_lock_interruptible(&rng_mutex);
|
|
if (err)
|
|
return -ERESTARTSYS;
|
|
buf[0] = '\0';
|
|
list_for_each_entry(rng, &rng_list, list) {
|
|
strncat(buf, rng->name, PAGE_SIZE - ret - 1);
|
|
ret += strlen(rng->name);
|
|
strncat(buf, " ", PAGE_SIZE - ret - 1);
|
|
ret++;
|
|
}
|
|
strncat(buf, "\n", PAGE_SIZE - ret - 1);
|
|
ret++;
|
|
mutex_unlock(&rng_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
|
|
hwrng_attr_current_show,
|
|
hwrng_attr_current_store);
|
|
static DEVICE_ATTR(rng_available, S_IRUGO,
|
|
hwrng_attr_available_show,
|
|
NULL);
|
|
|
|
|
|
static void unregister_miscdev(void)
|
|
{
|
|
device_remove_file(rng_miscdev.this_device, &dev_attr_rng_available);
|
|
device_remove_file(rng_miscdev.this_device, &dev_attr_rng_current);
|
|
misc_deregister(&rng_miscdev);
|
|
}
|
|
|
|
static int register_miscdev(void)
|
|
{
|
|
int err;
|
|
|
|
err = misc_register(&rng_miscdev);
|
|
if (err)
|
|
goto out;
|
|
err = device_create_file(rng_miscdev.this_device,
|
|
&dev_attr_rng_current);
|
|
if (err)
|
|
goto err_misc_dereg;
|
|
err = device_create_file(rng_miscdev.this_device,
|
|
&dev_attr_rng_available);
|
|
if (err)
|
|
goto err_remove_current;
|
|
out:
|
|
return err;
|
|
|
|
err_remove_current:
|
|
device_remove_file(rng_miscdev.this_device, &dev_attr_rng_current);
|
|
err_misc_dereg:
|
|
misc_deregister(&rng_miscdev);
|
|
goto out;
|
|
}
|
|
|
|
int hwrng_register(struct hwrng *rng)
|
|
{
|
|
int must_register_misc;
|
|
int err = -EINVAL;
|
|
struct hwrng *old_rng, *tmp;
|
|
|
|
if (rng->name == NULL ||
|
|
rng->data_read == NULL)
|
|
goto out;
|
|
|
|
mutex_lock(&rng_mutex);
|
|
|
|
/* Must not register two RNGs with the same name. */
|
|
err = -EEXIST;
|
|
list_for_each_entry(tmp, &rng_list, list) {
|
|
if (strcmp(tmp->name, rng->name) == 0)
|
|
goto out_unlock;
|
|
}
|
|
|
|
must_register_misc = (current_rng == NULL);
|
|
old_rng = current_rng;
|
|
if (!old_rng) {
|
|
err = hwrng_init(rng);
|
|
if (err)
|
|
goto out_unlock;
|
|
current_rng = rng;
|
|
}
|
|
err = 0;
|
|
if (must_register_misc) {
|
|
err = register_miscdev();
|
|
if (err) {
|
|
if (!old_rng) {
|
|
hwrng_cleanup(rng);
|
|
current_rng = NULL;
|
|
}
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
INIT_LIST_HEAD(&rng->list);
|
|
list_add_tail(&rng->list, &rng_list);
|
|
out_unlock:
|
|
mutex_unlock(&rng_mutex);
|
|
out:
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hwrng_register);
|
|
|
|
void hwrng_unregister(struct hwrng *rng)
|
|
{
|
|
int err;
|
|
|
|
mutex_lock(&rng_mutex);
|
|
|
|
list_del(&rng->list);
|
|
if (current_rng == rng) {
|
|
hwrng_cleanup(rng);
|
|
if (list_empty(&rng_list)) {
|
|
current_rng = NULL;
|
|
} else {
|
|
current_rng = list_entry(rng_list.prev, struct hwrng, list);
|
|
err = hwrng_init(current_rng);
|
|
if (err)
|
|
current_rng = NULL;
|
|
}
|
|
}
|
|
if (list_empty(&rng_list))
|
|
unregister_miscdev();
|
|
|
|
mutex_unlock(&rng_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hwrng_unregister);
|
|
|
|
|
|
MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");
|
|
MODULE_LICENSE("GPL");
|