Commit 6e592a06 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Jarkko Sakkinen
Browse files

tpm: Move Linux RNG connection to hwrng 



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: default avatarJason Gunthorpe <jgg@ziepe.ca>
Tested-by: default avatarPrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Tested-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent aad887f6

drivers/char/hw_random/Kconfig

+0 −13
Original line number Diff line number Diff line
@@ -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

drivers/char/hw_random/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 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

drivers/char/hw_random/tpm-rng.c

deleted100644 → 0
+0 −50
Original line number Diff line number Diff line 
/*

 * 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(NULL, 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@linux.vnet.ibm.com>");

MODULE_DESCRIPTION("RNG driver for TPM devices");

drivers/char/tpm/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -26,6 +26,17 @@ menuconfig TCG_TPM 


if TCG_TPM



config HW_RANDOM_TPM

	bool "TPM HW Random Number Generator support"

	depends on TCG_TPM && HW_RANDOM && !(TCG_TPM=y && HW_RANDOM=m)

	default y

	---help---

	  This setting exposes the TPM's Random Number Generator as a hwrng

	  device. This allows the kernel to collect randomness from the TPM at

	  boot, and provides the TPM randomines in /dev/hwrng.



	  If unsure, say Y.



config TCG_TIS_CORE

	tristate

	---help---

drivers/char/tpm/tpm-chip.c

+37 −5
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#include <linux/freezer.h>

#include <linux/major.h>

#include <linux/tpm_eventlog.h>



#include <linux/hw_random.h>

#include "tpm.h"



DEFINE_IDR(dev_nums_idr);
@@ -392,6 +392,26 @@ 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, hwrng);



	return tpm_get_random(chip, data, max);

}



static int tpm_add_hwrng(struct tpm_chip *chip)

{

	if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))

		return 0;



	snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),

		 "tpm-rng-%d", chip->dev_num);

	chip->hwrng.name = chip->hwrng_name;

	chip->hwrng.read = tpm_hwrng_read;

	return hwrng_register(&chip->hwrng);

}



/*

 * tpm_chip_register() - create a character device for the TPM chip

 * @chip: TPM chip to use.
@@ -424,11 +444,13 @@ 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) {
@@ -437,6 +459,14 @@ int tpm_chip_register(struct tpm_chip *chip) 
	}



	return 0;



out_hwrng:

	if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))

		hwrng_unregister(&chip->hwrng);

out_ppi:

	tpm_bios_log_teardown(chip);



	return rc;

}

EXPORT_SYMBOL_GPL(tpm_chip_register);
@@ -456,6 +486,8 @@ 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->hwrng);

	tpm_bios_log_teardown(chip);

	if (chip->flags & TPM_CHIP_FLAG_TPM2)

		cdev_device_del(&chip->cdevs, &chip->devs);

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