Commit 844dd05f authored by Michael Buesch's avatar Michael Buesch Committed by Linus Torvalds

[PATCH] Add new generic HW RNG core

Signed-off-by: default avatarMichael Buesch <mb@bu3sch.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 59f5d35f
......@@ -1118,6 +1118,11 @@ L: lm-sensors@lm-sensors.org
W: http://www.lm-sensors.nu/
S: Maintained
HARDWARE RANDOM NUMBER GENERATOR CORE
P: Michael Buesch
M: mb@bu3sch.de
S: Maintained
HARD DRIVE ACTIVE PROTECTION SYSTEM (HDAPS) DRIVER
P: Robert Love
M: rlove@rlove.org
......@@ -1436,6 +1441,11 @@ P: Tigran Aivazian
M: tigran@veritas.com
S: Maintained
INTEL IXP4XX RANDOM NUMBER GENERATOR SUPPORT
P: Deepak Saxena
M: dsaxena@plexity.net
S: Maintained
INTEL PRO/100 ETHERNET SUPPORT
P: John Ronciak
M: john.ronciak@intel.com
......@@ -2725,6 +2735,11 @@ P: Christoph Hellwig
M: hch@infradead.org
S: Maintained
TI OMAP RANDOM NUMBER GENERATOR SUPPORT
P: Deepak Saxena
M: dsaxena@plexity.net
S: Maintained
TI PARALLEL LINK CABLE DRIVER
P: Romain Lievin
M: roms@lpg.ticalc.org
......
......@@ -670,6 +670,8 @@ config NWFLASH
If you're not sure, say N.
source "drivers/char/hw_random/Kconfig"
config NVRAM
tristate "/dev/nvram support"
depends on ATARI || X86 || ARM || GENERIC_NVRAM
......
......@@ -75,6 +75,7 @@ endif
obj-$(CONFIG_TOSHIBA) += toshiba.o
obj-$(CONFIG_I8K) += i8k.o
obj-$(CONFIG_DS1620) += ds1620.o
obj-$(CONFIG_HW_RANDOM) += hw_random/
obj-$(CONFIG_FTAPE) += ftape/
obj-$(CONFIG_COBALT_LCD) += lcd.o
obj-$(CONFIG_PPDEV) += ppdev.o
......
#
# Hardware Random Number Generator (RNG) configuration
#
config HW_RANDOM
bool "Hardware Random Number Generator Core support"
default y
---help---
Hardware Random Number Generator Core infrastructure.
If unsure, say Y.
#
# Makefile for HW Random Number Generator (RNG) device drivers.
#
obj-$(CONFIG_HW_RANDOM) += core.o
/*
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/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)
{
if (!rng->data_present)
return 1;
return rng->data_present(rng);
}
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;
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 i, err = 0;
int data_present;
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;
}
if (filp->f_flags & O_NONBLOCK) {
data_present = hwrng_data_present(current_rng);
} else {
/* Some RNG require some time between data_reads to gather
* new entropy. Poll it.
*/
for (i = 0; i < 20; i++) {
data_present = hwrng_data_present(current_rng);
if (data_present)
break;
udelay(10);
}
}
bytes_read = 0;
if (data_present)
bytes_read = hwrng_data_read(current_rng, &data);
mutex_unlock(&rng_mutex);
err = -EAGAIN;
if (!bytes_read && (filp->f_flags & O_NONBLOCK))
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 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 class_device *class,
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 class_device *class,
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 class_device *class,
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 CLASS_DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
hwrng_attr_current_show,
hwrng_attr_current_store);
static CLASS_DEVICE_ATTR(rng_available, S_IRUGO,
hwrng_attr_available_show,
NULL);
static void unregister_miscdev(void)
{
class_device_remove_file(rng_miscdev.class,
&class_device_attr_rng_available);
class_device_remove_file(rng_miscdev.class,
&class_device_attr_rng_current);
misc_deregister(&rng_miscdev);
}
static int register_miscdev(void)
{
int err;
err = misc_register(&rng_miscdev);
if (err)
goto out;
err = class_device_create_file(rng_miscdev.class,
&class_device_attr_rng_current);
if (err)
goto err_misc_dereg;
err = class_device_create_file(rng_miscdev.class,
&class_device_attr_rng_available);
if (err)
goto err_remove_current;
out:
return err;
err_remove_current:
class_device_remove_file(rng_miscdev.class,
&class_device_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");
/*
Hardware Random Number Generator
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.
*/
#ifndef LINUX_HWRANDOM_H_
#define LINUX_HWRANDOM_H_
#ifdef __KERNEL__
#include <linux/types.h>
#include <linux/list.h>
/**
* struct hwrng - Hardware Random Number Generator driver
* @name: Unique RNG name.
* @init: Initialization callback (can be NULL).
* @cleanup: Cleanup callback (can be NULL).
* @data_present: Callback to determine if data is available
* on the RNG. If NULL, it is assumed that
* there is always data available.
* @data_read: Read data from the RNG device.
* Returns the number of lower random bytes in "data".
* Must not be NULL.
* @priv: Private data, for use by the RNG driver.
*/
struct hwrng {
const char *name;
int (*init)(struct hwrng *rng);
void (*cleanup)(struct hwrng *rng);
int (*data_present)(struct hwrng *rng);
int (*data_read)(struct hwrng *rng, u32 *data);
unsigned long priv;
/* internal. */
struct list_head list;
};
/** Register a new Hardware Random Number Generator driver. */
extern int hwrng_register(struct hwrng *rng);
/** Unregister a Hardware Random Number Generator driver. */
extern void hwrng_unregister(struct hwrng *rng);
#endif /* __KERNEL__ */
#endif /* LINUX_HWRANDOM_H_ */
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