[patch 2/6] New Generic HW RNG (#2)

Michael Buesch
2006-05-07T14:38:51Z

[-- Attachment #1: add-hw-random-core.patch --]
[-- Type: text/plain, Size: 11544 bytes --]

Add a new generic H/W RNG core.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Index: hwrng/drivers/char/Kconfig
===================================================================
--- hwrng.orig/drivers/char/Kconfig 2006-05-07 01:53:30.000000000 +0200
+++ hwrng/drivers/char/Kconfig 2006-05-07 01:55:11.000000000 +0200
@@ -670,6 +670,8 @@

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
Index: hwrng/drivers/char/Makefile
===================================================================
--- hwrng.orig/drivers/char/Makefile 2006-05-07 01:53:30.000000000 +0200
+++ hwrng/drivers/char/Makefile 2006-05-07 01:55:11.000000000 +0200
@@ -75,6 +75,7 @@
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-$(CONFIG_PPDEV) += ppdev.o
Index: hwrng/drivers/char/hw_random/Kconfig
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ hwrng/drivers/char/hw_random/Kconfig 2006-05-07 16:29:03.000000000 +0200
@@ -0,0 +1,11 @@
+#
+# Hardware Random Number Generator (RNG) configuration
+#
+
+config HW_RANDOM
+ bool "Hardware Random Number Generator Core support"
+ default y
+ ---help---
+ Hardware Random Number Generator Core infrastructure.
+
+ If unsure, say Y.
Index: hwrng/drivers/char/hw_random/Makefile
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ hwrng/drivers/char/hw_random/Makefile 2006-05-07 16:29:03.000000000 +0200
@@ -0,0 +1,5 @@
+#
+# Makefile for HW Random Number Generator (RNG) device drivers.
+#
+
+obj-$(CONFIG_HW_RANDOM) += core.o
Index: hwrng/drivers/char/hw_random/core.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ hwrng/drivers/char/hw_random/core.c 2006-05-07 16:26:43.000000000 +0200
@@ -0,0 +1,337 @@
+/*
+ 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 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)
+{
+ unsigned int have_data;
+ u32 data = 0;
+ ssize_t ret = 0;
+ int i, err;
+
+ while (size) {
+ err = mutex_lock_interruptible(&rng_mutex);
+ if (err)
+ return ret ? : -ERESTARTSYS;
+ if (!current_rng) {
+ mutex_unlock(&rng_mutex);
+ return ret ? : -ENODEV;
+ }
+ have_data = 0;
+ if (current_rng->data_present == NULL ||
+ current_rng->data_present(current_rng))
+ have_data = current_rng->data_read(current_rng, &data);
+ mutex_unlock(&rng_mutex);
+
+ while (have_data && size) {
+ if (put_user((u8)data, buf++)) {
+ ret = ret ? : -EFAULT;
+ break;
+ }
+ size--;
+ ret++;
+ have_data--;
+ data>>=8;
+ }
+
+ if (filp->f_flags & O_NONBLOCK)
+ return ret ? : -EAGAIN;
+
+ if (need_resched()) {
+ if (schedule_timeout_interruptible(1))
+ return ret ? : -ERESTARTSYS;
+ } else {
+ err = mutex_lock_interruptible(&rng_mutex);
+ if (err)
+ return ret ? : -ERESTARTSYS;
+ if (!current_rng) {
+ mutex_unlock(&rng_mutex);
+ return ret ? : -ENODEV;
+ }
+ for (i = 0; i < 20; i++) {
+ if (current_rng->data_present == NULL ||
+ current_rng->data_present(current_rng))
+ break;
+ udelay(10);
+ }
+ mutex_unlock(&rng_mutex);
+ }
+
+ if (signal_pending(current))
+ return ret ? : -ERESTARTSYS;
+ }
+ return ret;
+}
+
+
+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;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ 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;
+ }
+ if (rng->init) {
+ err = rng->init(rng);
+ if (err)
+ break;
+ }
+ if (current_rng && current_rng->cleanup)
+ current_rng->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;
+ struct hwrng *old_rng, *tmp;
+
+ if (rng->name == NULL)
+ return -EINVAL;
+ if (rng->data_read == NULL)
+ return -EINVAL;
+
+ mutex_lock(&rng_mutex);
+
+ /* Must not register two RNGs with the same name. */
+ list_for_each_entry(tmp, &rng_list, list) {
+ if (strcmp(tmp->name, rng->name) == 0)
+ return -EEXIST;
+ }
+
+ must_register_misc = (current_rng == NULL);
+ old_rng = current_rng;
+ if (!old_rng) {
+ if (rng->init) {
+ err = rng->init(rng);
+ if (err) {
+ mutex_unlock(&rng_mutex);
+ return err;
+ }
+ }
+ current_rng = rng;
+ }
+ INIT_LIST_HEAD(&rng->list);
+ list_add_tail(&rng->list, &rng_list);
+ err = 0;
+ if (must_register_misc) {
+ err = register_miscdev();
+ if (err) {
+ list_del(&rng->list);
+ if (!old_rng) {
+ if (rng->cleanup)
+ rng->cleanup(rng);
+ current_rng = NULL;
+ }
+ }
+ }
+
+ mutex_unlock(&rng_mutex);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(hwrng_register);
+
+void hwrng_unregister(struct hwrng *rng)
+{
+ mutex_lock(&rng_mutex);
+
+ list_del(&rng->list);
+ if (current_rng == rng) {
+ if (rng->cleanup)
+ rng->cleanup(rng);
+ if (list_empty(&rng_list))
+ current_rng = NULL;
+ else
+ current_rng = list_entry(rng_list.prev, struct hwrng, list);
+ }
+ if (list_empty(&rng_list))
+ unregister_miscdev();
+
+ mutex_unlock(&rng_mutex);
+}
+EXPORT_SYMBOL_GPL(hwrng_unregister);
+
+
+MODULE_AUTHOR("The Linux Kernel team");
+MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");
+MODULE_LICENSE("GPL");
Index: hwrng/include/linux/hw_random.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ hwrng/include/linux/hw_random.h 2006-05-06 23:56:06.000000000 +0200
@@ -0,0 +1,50 @@
+/*
+ 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_ */

--