RNG device is registered as soon as tpm-rng module is loaded even if
there are no TPM chip available. Call hwrng_register once tpm chip has
registered.
Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx>
---
drivers/char/hw_random/tpm-rng.c | 50 ----------------------------------------
drivers/char/tpm/tpm-chip.c | 24 +++++++++++++++++++
drivers/char/tpm/tpm.h | 3 +++
3 files changed, 27 insertions(+), 50 deletions(-)
delete mode 100644 drivers/char/hw_random/tpm-rng.c
diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c
deleted file mode 100644
index d6d4482..0000000
--- a/drivers/char/hw_random/tpm-rng.c
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Copyright (C) 2012 Kent Yoder IBM Corporation
- *
- * HWRNG interfaces to pull RNG data from a TPM
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-#include <linux/module.h>
-#include <linux/hw_random.h>
-#include <linux/tpm.h>
-
-#define MODULE_NAME "tpm-rng"
-
-static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
-{
- return tpm_get_random(TPM_ANY_NUM, data, max);
-}
-
-static struct hwrng tpm_rng = {
- .name = MODULE_NAME,
- .read = tpm_rng_read,
-};
-
-static int __init rng_init(void)
-{
- return hwrng_register(&tpm_rng);
-}
-module_init(rng_init);
-
-static void __exit rng_exit(void)
-{
- hwrng_unregister(&tpm_rng);
-}
-module_exit(rng_exit);
-
-MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Kent Yoder <key@xxxxxxxxxxxxxxxxxx>");
-MODULE_DESCRIPTION("RNG driver for TPM devices");
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 0eca20c..bf9c2ad 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -26,6 +26,7 @@
#include <linux/spinlock.h>
#include <linux/freezer.h>
#include <linux/major.h>
+#include <linux/hw_random.h>
#include "tpm.h"
#include "tpm_eventlog.h"
@@ -387,6 +388,15 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
return 0;
}
+
+static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+ int chip_num = 0;
+
+ kstrtoint(&rng->name[8], 10, &chip_num);
+ return tpm_get_random(chip_num, data, max);
+}
+
/*
* tpm_chip_register() - create a character device for the TPM chip
* @chip: TPM chip to use.
@@ -401,6 +411,7 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
int tpm_chip_register(struct tpm_chip *chip)
{
int rc;
+ char *tpm_rng_name;
if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
if (chip->flags & TPM_CHIP_FLAG_TPM2)
@@ -431,6 +442,14 @@ int tpm_chip_register(struct tpm_chip *chip)
return rc;
}
+ tpm_rng_name = kmalloc(64, GFP_KERNEL);
+
+ if (tpm_rng_name) {
+ sprintf(tpm_rng_name, "tpm-rng-%d", chip->dev_num);
+ tpm_rng.name = tpm_rng_name;
+ tpm_rng.read = tpm_rng_read;
+ hwrng_register(&tpm_rng);
+ }
return 0;
}
EXPORT_SYMBOL_GPL(tpm_chip_register);
@@ -450,6 +469,11 @@ EXPORT_SYMBOL_GPL(tpm_chip_register);
*/
void tpm_chip_unregister(struct tpm_chip *chip)
{
+ if (chip->tpm_rng.name[0] != 0) {
+ hwrng_unregister(&tpm_rng);
+ kfree(chip->tpm_rng.name);
+ chip->tpm_rng.name[0] = 0;
+ }
tpm_del_legacy_sysfs(chip);
tpm_bios_log_teardown(chip);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index b50e92f..ca042f7 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -26,6 +26,7 @@
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/fs.h>
+#include <linux/hw_random.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/platform_device.h>
@@ -210,6 +211,8 @@ struct tpm_chip {
int dev_num; /* /dev/tpm# */
unsigned long is_open; /* only one allowed */
+ struct hwrng tpm_rng;
+
struct mutex tpm_mutex; /* tpm is processing */
unsigned long timeout_a; /* jiffies */
--
2.10.0
