The tpm-rng.c approach is completely inconsistent with how the kernel
handles hotplug. Instead manage a hwrng device for each TPM. This will
cause the kernel to read entropy from the TPM when it is plugged in,
and allow access to the TPM rng via /dev/hwrng.
Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/hw_random/Kconfig | 13 -----------
drivers/char/hw_random/Makefile | 1 -
drivers/char/hw_random/tpm-rng.c | 50 ----------------------------------------
drivers/char/tpm/Kconfig | 13 +++++++++++
drivers/char/tpm/tpm-chip.c | 41 ++++++++++++++++++++++++++++----
drivers/char/tpm/tpm-interface.c | 37 ++++++++++++++++-------------
drivers/char/tpm/tpm.h | 5 ++++
7 files changed, 76 insertions(+), 84 deletions(-)
delete mode 100644 drivers/char/hw_random/tpm-rng.c
All,
It is such a good idea, I took PrasannaKumar's patch, reviewed and
revised it to the level it could be merged.
This is compile tested only.
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 95a031e9eced07..a20fed182cbcce 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -306,19 +306,6 @@ config HW_RANDOM_POWERNV
If unsure, say Y.
-config HW_RANDOM_TPM
- tristate "TPM HW Random Number Generator support"
- depends on TCG_TPM
- default HW_RANDOM
- ---help---
- This driver provides kernel-side support for the Random Number
- Generator in the Trusted Platform Module
-
- To compile this driver as a module, choose M here: the
- module will be called tpm-rng.
-
- If unsure, say Y.
-
config HW_RANDOM_HISI
tristate "Hisilicon Random Number Generator support"
depends on HW_RANDOM && ARCH_HISI
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 39a67defac67cb..91cb8e8213e7c1 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -26,7 +26,6 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
obj-$(CONFIG_HW_RANDOM_HISI) += hisi-rng.o
-obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o
diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c
deleted file mode 100644
index d6d448266f0752..00000000000000
--- 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/Kconfig b/drivers/char/tpm/Kconfig
index a30352202f1fdc..a95725fa77789e 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -26,6 +26,19 @@ menuconfig TCG_TPM
if TCG_TPM
+config HW_RANDOM_TPM
+ tristate "TPM HW Random Number Generator support"
+ depends on TCG_TPM && HW_RANDOM
+ default HW_RANDOM
+ ---help---
+ This driver provides kernel-side support for the Random Number
+ Generator in the Trusted Platform Module
+
+ To compile this driver as a module, choose M here: the
+ module will be called tpm-rng.
+
+ If unsure, say Y.
+
config TCG_TIS_CORE
tristate
---help---
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 0eca20c5a80cf2..f3571406fb2995 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 +388,26 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
return 0;
}
+
+static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+ struct tpm_chip *chip = container_of(rng, struct tpm_chip, tpm_hwrng);
+
+ return tpm_get_random_dev(chip, data, max);
+}
+
+static int tpm_add_hwrng(struct tpm_chip *chip)
+{
+ if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
+ return 0;
+
+ snprintf(chip->tpm_hwrng_name, sizeof(chip->tpm_hwrng_name),
+ "tpm-rng-%d", chip->dev_num);
+ chip->tpm_hwrng.name = chip->tpm_hwrng_name;
+ chip->tpm_hwrng.read = tpm_hwrng_read;
+ return hwrng_register(&chip->tpm_hwrng);
+}
+
/*
* tpm_chip_register() - create a character device for the TPM chip
* @chip: TPM chip to use.
@@ -419,11 +440,13 @@ int tpm_chip_register(struct tpm_chip *chip)
tpm_add_ppi(chip);
+ rc = tpm_add_hwrng(chip);
+ if (rc)
+ goto out_ppi;
+
rc = tpm_add_char_device(chip);
- if (rc) {
- tpm_bios_log_teardown(chip);
- return rc;
- }
+ if (rc)
+ goto out_hwrng;
rc = tpm_add_legacy_sysfs(chip);
if (rc) {
@@ -432,6 +455,14 @@ int tpm_chip_register(struct tpm_chip *chip)
}
return 0;
+
+out_hwrng:
+ if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
+ hwrng_unregister(&chip->tpm_hwrng);
+out_ppi:
+ tpm_bios_log_teardown(chip);
+
+ return rc;
}
EXPORT_SYMBOL_GPL(tpm_chip_register);
@@ -451,6 +482,8 @@ EXPORT_SYMBOL_GPL(tpm_chip_register);
void tpm_chip_unregister(struct tpm_chip *chip)
{
tpm_del_legacy_sysfs(chip);
+ if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
+ hwrng_unregister(&chip->tpm_hwrng);
tpm_bios_log_teardown(chip);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
cdev_device_del(&chip->cdevs, &chip->devs);
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1d6729be4cd637..310de288549818 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1194,9 +1194,8 @@ static const struct tpm_input_header tpm_getrandom_header = {
*
* Returns < 0 on error and the number of bytes read on success
*/
-int tpm_get_random(u32 chip_num, u8 *out, size_t max)
+int tpm_get_random_dev(struct tpm_chip *chip, u8 *out, size_t max)
{
- struct tpm_chip *chip;
struct tpm_cmd_t tpm_cmd;
u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA), rlength;
int err, total = 0, retries = 5;
@@ -1205,15 +1204,8 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
return -EINVAL;
- chip = tpm_chip_find_get(chip_num);
- if (chip == NULL)
- return -ENODEV;
-
- if (chip->flags & TPM_CHIP_FLAG_TPM2) {
- err = tpm2_get_random(chip, out, max);
- tpm_put_ops(chip);
- return err;
- }
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ return tpm2_get_random(chip, out, max);
do {
tpm_cmd.header.in = tpm_getrandom_header;
@@ -1231,10 +1223,9 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
rlength = be32_to_cpu(tpm_cmd.header.out.length);
if (rlength < offsetof(struct tpm_getrandom_out, rng_data) +
- recd) {
- total = -EFAULT;
- break;
- }
+ recd)
+ return -EFAULT;
+
memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd);
dest += recd;
@@ -1242,9 +1233,23 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
num_bytes -= recd;
} while (retries-- && total < max);
- tpm_put_ops(chip);
return total ? total : -EIO;
}
+
+int tpm_get_random(u32 chip_num, u8 *out, size_t max)
+{
+ int rc;
+ struct tpm_chip *chip;
+
+ chip = tpm_chip_find_get(chip_num);
+ if (chip == NULL)
+ return -ENODEV;
+
+ rc = tpm_get_random_dev(chip, out, max);
+
+ tpm_put_ops(chip);
+ return rc;
+}
EXPORT_SYMBOL_GPL(tpm_get_random);
/**
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 2d5466a72e40f8..0e41e044d81be2 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 +211,9 @@ struct tpm_chip {
int dev_num; /* /dev/tpm# */
unsigned long is_open; /* only one allowed */
+ char tpm_hwrng_name[64];
+ struct hwrng tpm_hwrng;
+
struct mutex tpm_mutex; /* tpm is processing */
unsigned long timeout_a; /* jiffies */
@@ -548,6 +552,7 @@ void tpm_chip_unregister(struct tpm_chip *chip);
void tpm_sysfs_add_device(struct tpm_chip *chip);
int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
+int tpm_get_random_dev(struct tpm_chip *chip, u8 *out, size_t max);
#ifdef CONFIG_ACPI
extern void tpm_add_ppi(struct tpm_chip *chip);
--
2.7.4
