diff mbox

[v3,7/7] tpm: Adds securityfs support for TPM2.0 eventlog

Message ID 1472532619-22170-8-git-send-email-nayna@linux.vnet.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Nayna Aug. 30, 2016, 4:50 a.m. UTC 
Adds securityfs support for TPM2.0.
This patch add supports only for binary_bios_measurements.

Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
---
 drivers/char/tpm/Makefile            |   2 +-
 drivers/char/tpm/tpm2.h              |  85 +++++++++++++
 drivers/char/tpm/tpm2_eventlog.c     | 224 +++++++++++++++++++++++++++++++++++
 drivers/char/tpm/tpm_eventlog_init.c |  28 +++--
 drivers/char/tpm/tpm_of.c            |  42 ++++---
 5 files changed, 357 insertions(+), 24 deletions(-)
 create mode 100644 drivers/char/tpm/tpm2.h
 create mode 100644 drivers/char/tpm/tpm2_eventlog.c

Comments

Jarkko Sakkinen Aug. 30, 2016, 8:21 a.m. UTC | #1 
On Tue, Aug 30, 2016 at 12:50:19AM -0400, Nayna Jain wrote:
> Adds securityfs support for TPM2.0.
> This patch add supports only for binary_bios_measurements.

You should use more time to your commit messages. Descriptions like
this are unacceptable.

> Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
> ---
>  drivers/char/tpm/Makefile            |   2 +-
>  drivers/char/tpm/tpm2.h              |  85 +++++++++++++
>  drivers/char/tpm/tpm2_eventlog.c     | 224 +++++++++++++++++++++++++++++++++++
>  drivers/char/tpm/tpm_eventlog_init.c |  28 +++--
>  drivers/char/tpm/tpm_of.c            |  42 ++++---
>  5 files changed, 357 insertions(+), 24 deletions(-)
>  create mode 100644 drivers/char/tpm/tpm2.h
>  create mode 100644 drivers/char/tpm/tpm2_eventlog.c
> 
> diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
> index 200b957..b10316d 100644
> --- a/drivers/char/tpm/Makefile
> +++ b/drivers/char/tpm/Makefile
> @@ -3,7 +3,7 @@
>  #
>  obj-$(CONFIG_TCG_TPM) += tpm.o
>  tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
> -	tpm_eventlog.o tpm_eventlog_init.o
> +	tpm_eventlog.o tpm_eventlog_init.o tpm2_eventlog.o
>  
>  tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
>  tpm-$(CONFIG_OF) += tpm_of.o
> diff --git a/drivers/char/tpm/tpm2.h b/drivers/char/tpm/tpm2.h
> new file mode 100644
> index 0000000..38a8073
> --- /dev/null
> +++ b/drivers/char/tpm/tpm2.h
> @@ -0,0 +1,85 @@
> +#ifndef __TPM2_H__
> +#define __TPM2_H__
> +
> +#define TPM_ALG_SHA1_DIGEST_SIZE	20
> +#define TPM_ALG_SHA256_DIGEST_SIZE	32
> +#define TPM_ALG_SHA384_DIGEST_SIZE	48
> +
> +#define HASH_COUNT	3
> +#define MAX_TPM_LOG_MSG	128
> +
> +/**
> + * All the structures related to Event Log are taken from TCG EFI Protocol
> + * Specification, Family "2.0". Document is available on link
> + * http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/
> + * Information is also available on TCG PC Client Platform Firmware Profile
> + * Specification, Family "2.0"
> + * Detailed digest structures for TPM2.0 are defined in document
> + * Trusted Platform Module Library Part 2: Structures, Family "2.0".
> + */
> +
> +/* Event log header algorithm spec. */
> +struct tcg_efispecideventalgorithmsize {
> +	u16	algorithm_id;
> +	u16	digest_size;
> +} __packed;
> +
> +/* Event log header data. */
> +struct tcg_efispecideventstruct {
> +	u8					signature[16];
> +	u32					platform_class;
> +	u8					spec_version_minor;
> +	u8					spec_version_major;
> +	u8					spec_errata;
> +	u8					uintnsize;
> +	u32					num_algs;
> +	struct tcg_efispecideventalgorithmsize	digest_sizes[HASH_COUNT];
> +	u8					vendor_info_size;
> +	u8					vendor_info[0];
> +} __packed;
> +
> +/* Header entry for eventlog. */
> +struct tcg_pcr_event {
> +	u32	pcr_index;
> +	u32	event_type;
> +	u8	digest[20];
> +	u32	event_size;
> +	u8	event[MAX_TPM_LOG_MSG];
> +} __packed;
> +
> +/* Digest union for crypto agility. */
> +union tpmu_ha {
> +	u8	 sha1[TPM_ALG_SHA1_DIGEST_SIZE];
> +	u8	 sha256[TPM_ALG_SHA256_DIGEST_SIZE];
> +	u8	 sha384[TPM_ALG_SHA384_DIGEST_SIZE];
> +} __packed;
> +
> +/* Crypto Agile algorithm and respective digest. */
> +struct tpmt_ha {
> +	u16		algorithm_id;
> +	union tpmu_ha	digest;
> +} __packed;
> +
> +/* Crypto agile digests list. */
> +struct tpml_digest_values {
> +	u32		count;
> +	struct tpmt_ha	digests[HASH_COUNT];
> +} __packed;
> +
> +/* Event field structure. */
> +struct tcg_event_field {
> +	u32	event_size;
> +	u8      event[MAX_TPM_LOG_MSG];
> +} __packed;
> +
> +/* Crypto agile log entry format for TPM 2.0. */
> +struct tcg_pcr_event2 {
> +	u32				pcr_index;
> +	u32				event_type;
> +	struct tpml_digest_values	digests;
> +	struct tcg_event_field		event;
> +} __packed;
> +
> +extern const struct seq_operations tpm2_binary_b_measurments_seqops;
> +
> +#endif
> diff --git a/drivers/char/tpm/tpm2_eventlog.c b/drivers/char/tpm/tpm2_eventlog.c
> new file mode 100644
> index 0000000..f1e8c4a
> --- /dev/null
> +++ b/drivers/char/tpm/tpm2_eventlog.c
> @@ -0,0 +1,224 @@
> +/*
> + * Copyright (C) 2016 IBM Corporation
> + *
> + * Authors:
> + *      Nayna Jain <nayna@linux.vnet.ibm.com>
> +
> + * Access to TPM2.0 event log as written by Firmware.
> + * It assumes that writer of event log has followed TCG Spec 2.0
> + * has written the event struct data in little endian. With that,
> + * it doesn't need any endian conversion for structure content.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version
> + * 2 of the License, or (at your option) any later version.
> + */
> +
> +#include <linux/seq_file.h>
> +#include <linux/fs.h>
> +#include <linux/security.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +#include "tpm.h"
> +#include "tpm2.h"
> +#include "tpm_eventlog.h"
> +
> +
> +static int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
> +		struct tcg_pcr_event *event_header)
> +{
> +	struct tcg_efispecideventstruct *efispecid;
> +	struct tcg_event_field *event_field;
> +	void *marker, *marker_start;
> +	int j;
> +	size_t size = 0;
> +
> +	/*
> +	 * NOTE: TPM2.0 allows support for extend to multiple PCR Banks.
> +	 * This implies that eventlog also has multiple digest values
> +	 * one for each PCR Bank. This is called Crypto Agile Log Entry
> +	 * Format. Current support implementation is for SHA1 and SHA256.
> +	 * Number of digest values are identified by parsing first
> +	 * structure stored in event log also called event header.
> +	 * Further, the eventlog is written in packed form so to calculate
> +	 * offset it is important to know the type of algorithm used.
> +	 * Eg. 1:
> +	 * digest_values.count = 1;
> +	 * digest_values.digest[0].algorithm_id = sha1;
> +	 * digest_values.digest[0].digest.sha1 = {20 bytes raw data};
> +	 * Offset of eventsize is sizeof(count) + sizeof(algorithm_id) + 20
> +	 *
> +	 * Eg. 2:
> +	 * digest_values.count = 1;
> +	 * digest_values.digest[0].algorithm_id = sha256;
> +	 * digest_values.digest[0].digest.sha1 = {32 bytes raw data};
> +	 * Offset of eventsize is sizeof(count) + sizeof(algorithm_id) + 32
> +
> +	 * Eg. 3:
> +	 * digest_values.count = 2;
> +	 * digest_values.digest[0].algorithm_id = sha1;
> +	 * digest_values.digest[0].digest.sha1 = {20 bytes raw data};
> +	 * digest_values.digest[1].algorithm_id = sha256;
> +	 * digest_values.digest[1].digest.sha256 = {32 bytes raw data};
> +	 * Offset of eventsize is sizeof(count) + sizeof(algorithm_id) + 20
> +	 *			+ sizeof(algorithm_id) + 32;
> +	 *
> +	 * So, it implies that offset of event_size can vary based on digest
> +	 * values as defined by vendor. And so we have to calculate the
> +	 * offset by parsing through number and type of digests being used.
> +	 * And this is the purpose of using *marker to traverse the structure
> +	 * and calculate the offset of event_size. This function uses *marker
> +	 * to parse and calculate the dynamic size of the whole event structure.
> +	 */
> +
> +	marker = event;
> +	marker_start = marker;
> +	marker = marker + sizeof(event->pcr_index) + sizeof(event->event_type)
> +		+ sizeof(event->digests.count);
> +
> +	efispecid = (struct tcg_efispecideventstruct *) event_header->event;
> +
> +	for (j = 0; (j < efispecid->num_algs) && (j < HASH_COUNT); j++) {
> +		marker = marker
> +			+ sizeof(efispecid->digest_sizes[j].algorithm_id);
> +		marker = marker + efispecid->digest_sizes[j].digest_size;
> +	}
> +
> +	event_field = (struct tcg_event_field *) marker;
> +	marker = marker + sizeof(event_field->event_size)
> +		+ event_field->event_size;
> +	size = marker - marker_start;
> +
> +	if ((event->event_type == 0) && (event_field->event_size == 0))
> +		return 0;
> +
> +	return size;
> +}
> +
> +static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
> +{
> +	struct tpm_bios_log *log = m->private;
> +	void *addr = log->bios_event_log;
> +	void *limit = log->bios_event_log_end;
> +	struct tcg_pcr_event *event_header;
> +	struct tcg_pcr_event2 *event;
> +	int i;
> +	size_t size = 0;
> +
> +	event_header = addr;
> +
> +	size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event)
> +		+ event_header->event_size;
> +
> +
> +	if (*pos == 0) {
> +		if (addr + size < limit) {
> +			if ((event_header->event_type == 0) &&
> +					(event_header->event_size == 0))
> +				return NULL;
> +			return SEQ_START_TOKEN;
> +		}
> +	}
> +
> +	if (*pos > 0) {
> +		addr += size;
> +		event = addr;
> +		size = calc_tpm2_event_size(event, event_header);
> +		if ((addr + size >=  limit) || (size == 0))
> +			return NULL;
> +	}
> +
> +	/* read over *pos measurements */
> +	for (i = 0; i < (*pos - 1); i++) {
> +		event = addr;
> +		size = calc_tpm2_event_size(event, event_header);
> +
> +		if ((addr + size >= limit) || (size == 0))
> +			return NULL;
> +		addr += size;
> +	}
> +
> +	return addr;
> +}
> +
> +static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
> +		loff_t *pos)
> +{
> +	struct tcg_pcr_event *event_header;
> +	struct tcg_pcr_event2 *event;
> +	struct tpm_bios_log *log = m->private;
> +	void *limit = log->bios_event_log_end;
> +	void *marker;
> +	size_t event_size = 0;
> +
> +	event_header = log->bios_event_log;
> +
> +	if (v == SEQ_START_TOKEN) {
> +		event_size = sizeof(struct tcg_pcr_event)
> +			- sizeof(event_header->event)
> +			+ event_header->event_size;
> +		marker = event_header;
> +	} else {
> +		event = v;
> +		event_size = calc_tpm2_event_size(event, event_header);
> +		if (event_size == 0)
> +			return NULL;
> +		marker =  event;
> +	}
> +
> +	marker = marker + event_size;
> +	if (marker >= limit)
> +		return NULL;
> +	v = marker;
> +	event = v;
> +
> +	event_size = calc_tpm2_event_size(event, event_header);
> +	if (((v + event_size) >= limit) || (event_size == 0))
> +		return NULL;
> +
> +	(*pos)++;
> +	return v;
> +}
> +
> +static void tpm2_bios_measurements_stop(struct seq_file *m, void *v)
> +{
> +}
> +
> +static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
> +{
> +	struct tpm_bios_log *log = m->private;
> +	struct tcg_pcr_event *event_header = log->bios_event_log;
> +	struct tcg_pcr_event2 *event = v;
> +	void *temp_ptr;
> +	size_t size = 0;
> +
> +	if (v == SEQ_START_TOKEN) {
> +
> +		size = sizeof(struct tcg_pcr_event)
> +			- sizeof(event_header->event)
> +			+ event_header->event_size;
> +
> +		temp_ptr = event_header;
> +
> +		if (size > 0)
> +			seq_write(m, temp_ptr, size);
> +	} else {
> +
> +		size = calc_tpm2_event_size(event, event_header);
> +
> +		temp_ptr = event;
> +		if (size > 0)
> +			seq_write(m, temp_ptr, size);
> +	}
> +
> +	return 0;
> +}
> +
> +const struct seq_operations tpm2_binary_b_measurments_seqops = {
> +	.start = tpm2_bios_measurements_start,
> +	.next = tpm2_bios_measurements_next,
> +	.stop = tpm2_bios_measurements_stop,
> +	.show = tpm2_binary_bios_measurements_show,
> +};
> diff --git a/drivers/char/tpm/tpm_eventlog_init.c b/drivers/char/tpm/tpm_eventlog_init.c
> index 038771a..9afeb3d 100644
> --- a/drivers/char/tpm/tpm_eventlog_init.c
> +++ b/drivers/char/tpm/tpm_eventlog_init.c
> @@ -28,6 +28,7 @@
>  #include <linux/slab.h>
>  
>  #include "tpm.h"
> +#include "tpm2.h"
>  #include "tpm_eventlog.h"
>  
>  static int tpm_bios_measurements_release(struct inode *inode,
> @@ -94,6 +95,7 @@ int read_log(struct tpm_chip *chip)
>  void tpm_bios_log_setup(struct tpm_chip *chip)
>  {
>  	const char *name = dev_name(&chip->dev);
> +	void *seq_ops;
>  	int rc = 0;
>  
>  	rc = read_log(chip);
> @@ -108,23 +110,31 @@ void tpm_bios_log_setup(struct tpm_chip *chip)
>  	chip->bios_dir[chip->bios_dir_count]->d_inode->i_private = chip;
>  	chip->bios_dir_count++;
>  
> +	if (chip->flags & TPM_CHIP_FLAG_TPM2)
> +		seq_ops = (void *)&tpm2_binary_b_measurments_seqops;
> +	else
> +		seq_ops = (void *)&tpm_binary_b_measurments_seqops;
> +
> +
>  	chip->bios_dir[chip->bios_dir_count] =
>  	    securityfs_create_file("binary_bios_measurements",
>  				   S_IRUSR | S_IRGRP, chip->bios_dir[0],
> -				   (void *)&tpm_binary_b_measurments_seqops,
> +				   seq_ops,
>  				   &tpm_bios_measurements_ops);
>  	if (is_bad(chip->bios_dir[chip->bios_dir_count]))
>  		goto err;
>  	chip->bios_dir_count++;
>  
> -	chip->bios_dir[chip->bios_dir_count] =
> -	    securityfs_create_file("ascii_bios_measurements",
> -				   S_IRUSR | S_IRGRP, chip->bios_dir[0],
> -				   (void *)&tpm_ascii_b_measurments_seqops,
> -				   &tpm_bios_measurements_ops);
> -	if (is_bad(chip->bios_dir[chip->bios_dir_count]))
> -		goto err;
> -	chip->bios_dir_count++;
> +	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
> +		chip->bios_dir[chip->bios_dir_count] =
> +			securityfs_create_file("ascii_bios_measurements",
> +					S_IRUSR | S_IRGRP, chip->bios_dir[0],
> +					(void *)&tpm_ascii_b_measurments_seqops,
> +					&tpm_bios_measurements_ops);
> +		if (is_bad(chip->bios_dir[chip->bios_dir_count]))
> +			goto err;
> +		chip->bios_dir_count++;
> +	}
>  
>  	return;
>  
> diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
> index 4e4eed7..2fc58fe 100644
> --- a/drivers/char/tpm/tpm_of.c
> +++ b/drivers/char/tpm/tpm_of.c
> @@ -15,12 +15,10 @@
>   *
>   */
>  
> -#include <linux/seq_file.h>
> -#include <linux/fs.h>
> -#include <linux/security.h>
> -#include <linux/module.h>
>  #include <linux/slab.h>
> +#include <linux/of_device.h>
>  #include <linux/of.h>
> +#include <linux/string.h>
>  
>  #include "tpm.h"
>  #include "tpm_eventlog.h"
> @@ -30,44 +28,60 @@ int read_log_of(struct tpm_chip *chip)
>  	struct device_node *np;
>  	const u32 *sizep;
>  	const u64 *basep;
> +	const struct of_device_id *of_id;
> +	const char *compat;
> +	u32 log_size;
>  
>  	if (chip->dev.of_node)
>  		np = chip->dev.of_node;
>  	if (!np) {
> -		dev_dbg(&chip->dev, "%s: ERROR - IBMVTPM not supported\n",
> +		dev_dbg(&chip->dev, "%s: ERROR - TPM not supported\n",
>  			__func__);
>  		return -ENODEV;
>  	}
>  
> +	compat = of_get_property(np, "compatible", NULL);
> +	if (compat == NULL) {
> +		dev_dbg(&chip->dev, "%s: ERROR - Compatible device not found",
> +			__func__);
> +		return -EIO;
> +	}
> +
>  	sizep = of_get_property(np, "linux,sml-size", NULL);
>  	if (sizep == NULL) {
>  		dev_dbg(&chip->dev, "%s: ERROR - SML size not found\n",
>  			__func__);
> -		goto cleanup_eio;
> +		return -EIO;
>  	}
>  	if (*sizep == 0) {
>  		dev_dbg(&chip->dev, "%s: ERROR - event log area empty\n",
>  			__func__);
> -		goto cleanup_eio;
> +		return -EIO;
>  	}
>  
> +	if (!strcasecmp(compat, "IBM,vtpm"))
> +		log_size = *sizep;
> +	else
> +		log_size = be32_to_cpup(sizep);
> +
>  	basep = of_get_property(np, "linux,sml-base", NULL);
>  	if (basep == NULL) {
>  		dev_dbg(&chip->dev, "%s: ERROR - SML not found\n", __func__);
> -		goto cleanup_eio;
> +		return -EIO;
>  	}
>  
> -	chip->log.bios_event_log = kmalloc(*sizep, GFP_KERNEL);
> +	chip->log.bios_event_log = kmalloc(log_size, GFP_KERNEL);
>  	if (!chip->log.bios_event_log) {
>  		return -ENOMEM;
>  	}
>  
> -	chip->log.bios_event_log_end = chip->log.bios_event_log + *sizep;
> +	chip->log.bios_event_log_end = chip->log.bios_event_log + log_size;
>  
> -	memcpy(chip->log.bios_event_log, __va(*basep), *sizep);
> +	if (!strcasecmp(compat, "IBM,vtpm"))
> +		memcpy(chip->log.bios_event_log, __va(*basep), log_size);
> +	else
> +		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
> +				log_size);
>  
>  	return 0;
> -
> -cleanup_eio:
> -	return -EIO;
>  }
> -- 
> 2.5.0
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> tpmdd-devel mailing list
> tpmdd-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/tpmdd-devel

/Jarkko

------------------------------------------------------------------------------
Jason Gunthorpe Aug. 30, 2016, 5:59 p.m. UTC | #2 
On Tue, Aug 30, 2016 at 12:50:19AM -0400, Nayna Jain wrote:
>  	if (chip->dev.of_node)
>  		np = chip->dev.of_node;
>  	if (!np) {
> -		dev_dbg(&chip->dev, "%s: ERROR - IBMVTPM not supported\n",
> +		dev_dbg(&chip->dev, "%s: ERROR - TPM not supported\n",
>  			__func__);

ERm, this is a mistake in the earlier patch that adds OF and ACPI
together.

Do not print anything if OF is present but no event log is
defined. Ditto for ACPI.

Do not print anything if there is no OF node either.

> +	if (!strcasecmp(compat, "IBM,vtpm"))

No, this is the wrong way to work with compatible lists. I'm pretty
sure there is an OF helper to do this.

> +		log_size = *sizep;

???

All DT values should be big endian. Please include a comment
explaining why this is would not be the case.

Are you certain this isn't just a pre-existing bug - the code assumed
host endian because it was always running on big endian PPC?

Jason

------------------------------------------------------------------------------
diff mbox

Patch

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 200b957..b10316d 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -3,7 +3,7 @@ 
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
 tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
-	tpm_eventlog.o tpm_eventlog_init.o
+	tpm_eventlog.o tpm_eventlog_init.o tpm2_eventlog.o
 
 tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
 tpm-$(CONFIG_OF) += tpm_of.o
diff --git a/drivers/char/tpm/tpm2.h b/drivers/char/tpm/tpm2.h
new file mode 100644
index 0000000..38a8073
--- /dev/null
+++ b/drivers/char/tpm/tpm2.h
@@ -0,0 +1,85 @@ 
+#ifndef __TPM2_H__
+#define __TPM2_H__
+
+#define TPM_ALG_SHA1_DIGEST_SIZE	20
+#define TPM_ALG_SHA256_DIGEST_SIZE	32
+#define TPM_ALG_SHA384_DIGEST_SIZE	48
+
+#define HASH_COUNT	3
+#define MAX_TPM_LOG_MSG	128
+
+/**
+ * All the structures related to Event Log are taken from TCG EFI Protocol
+ * Specification, Family "2.0". Document is available on link
+ * http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/
+ * Information is also available on TCG PC Client Platform Firmware Profile
+ * Specification, Family "2.0"
+ * Detailed digest structures for TPM2.0 are defined in document
+ * Trusted Platform Module Library Part 2: Structures, Family "2.0".
+ */
+
+/* Event log header algorithm spec. */
+struct tcg_efispecideventalgorithmsize {
+	u16	algorithm_id;
+	u16	digest_size;
+} __packed;
+
+/* Event log header data. */
+struct tcg_efispecideventstruct {
+	u8					signature[16];
+	u32					platform_class;
+	u8					spec_version_minor;
+	u8					spec_version_major;
+	u8					spec_errata;
+	u8					uintnsize;
+	u32					num_algs;
+	struct tcg_efispecideventalgorithmsize	digest_sizes[HASH_COUNT];
+	u8					vendor_info_size;
+	u8					vendor_info[0];
+} __packed;
+
+/* Header entry for eventlog. */
+struct tcg_pcr_event {
+	u32	pcr_index;
+	u32	event_type;
+	u8	digest[20];
+	u32	event_size;
+	u8	event[MAX_TPM_LOG_MSG];
+} __packed;
+
+/* Digest union for crypto agility. */
+union tpmu_ha {
+	u8	 sha1[TPM_ALG_SHA1_DIGEST_SIZE];
+	u8	 sha256[TPM_ALG_SHA256_DIGEST_SIZE];
+	u8	 sha384[TPM_ALG_SHA384_DIGEST_SIZE];
+} __packed;
+
+/* Crypto Agile algorithm and respective digest. */
+struct tpmt_ha {
+	u16		algorithm_id;
+	union tpmu_ha	digest;
+} __packed;
+
+/* Crypto agile digests list. */
+struct tpml_digest_values {
+	u32		count;
+	struct tpmt_ha	digests[HASH_COUNT];
+} __packed;
+
+/* Event field structure. */
+struct tcg_event_field {
+	u32	event_size;
+	u8      event[MAX_TPM_LOG_MSG];
+} __packed;
+
+/* Crypto agile log entry format for TPM 2.0. */
+struct tcg_pcr_event2 {
+	u32				pcr_index;
+	u32				event_type;
+	struct tpml_digest_values	digests;
+	struct tcg_event_field		event;
+} __packed;
+
+extern const struct seq_operations tpm2_binary_b_measurments_seqops;
+
+#endif
diff --git a/drivers/char/tpm/tpm2_eventlog.c b/drivers/char/tpm/tpm2_eventlog.c
new file mode 100644
index 0000000..f1e8c4a
--- /dev/null
+++ b/drivers/char/tpm/tpm2_eventlog.c
@@ -0,0 +1,224 @@ 
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ *      Nayna Jain <nayna@linux.vnet.ibm.com>
+
+ * Access to TPM2.0 event log as written by Firmware.
+ * It assumes that writer of event log has followed TCG Spec 2.0
+ * has written the event struct data in little endian. With that,
+ * it doesn't need any endian conversion for structure content.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "tpm.h"
+#include "tpm2.h"
+#include "tpm_eventlog.h"
+
+
+static int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
+		struct tcg_pcr_event *event_header)
+{
+	struct tcg_efispecideventstruct *efispecid;
+	struct tcg_event_field *event_field;
+	void *marker, *marker_start;
+	int j;
+	size_t size = 0;
+
+	/*
+	 * NOTE: TPM2.0 allows support for extend to multiple PCR Banks.
+	 * This implies that eventlog also has multiple digest values
+	 * one for each PCR Bank. This is called Crypto Agile Log Entry
+	 * Format. Current support implementation is for SHA1 and SHA256.
+	 * Number of digest values are identified by parsing first
+	 * structure stored in event log also called event header.
+	 * Further, the eventlog is written in packed form so to calculate
+	 * offset it is important to know the type of algorithm used.
+	 * Eg. 1:
+	 * digest_values.count = 1;
+	 * digest_values.digest[0].algorithm_id = sha1;
+	 * digest_values.digest[0].digest.sha1 = {20 bytes raw data};
+	 * Offset of eventsize is sizeof(count) + sizeof(algorithm_id) + 20
+	 *
+	 * Eg. 2:
+	 * digest_values.count = 1;
+	 * digest_values.digest[0].algorithm_id = sha256;
+	 * digest_values.digest[0].digest.sha1 = {32 bytes raw data};
+	 * Offset of eventsize is sizeof(count) + sizeof(algorithm_id) + 32
+
+	 * Eg. 3:
+	 * digest_values.count = 2;
+	 * digest_values.digest[0].algorithm_id = sha1;
+	 * digest_values.digest[0].digest.sha1 = {20 bytes raw data};
+	 * digest_values.digest[1].algorithm_id = sha256;
+	 * digest_values.digest[1].digest.sha256 = {32 bytes raw data};
+	 * Offset of eventsize is sizeof(count) + sizeof(algorithm_id) + 20
+	 *			+ sizeof(algorithm_id) + 32;
+	 *
+	 * So, it implies that offset of event_size can vary based on digest
+	 * values as defined by vendor. And so we have to calculate the
+	 * offset by parsing through number and type of digests being used.
+	 * And this is the purpose of using *marker to traverse the structure
+	 * and calculate the offset of event_size. This function uses *marker
+	 * to parse and calculate the dynamic size of the whole event structure.
+	 */
+
+	marker = event;
+	marker_start = marker;
+	marker = marker + sizeof(event->pcr_index) + sizeof(event->event_type)
+		+ sizeof(event->digests.count);
+
+	efispecid = (struct tcg_efispecideventstruct *) event_header->event;
+
+	for (j = 0; (j < efispecid->num_algs) && (j < HASH_COUNT); j++) {
+		marker = marker
+			+ sizeof(efispecid->digest_sizes[j].algorithm_id);
+		marker = marker + efispecid->digest_sizes[j].digest_size;
+	}
+
+	event_field = (struct tcg_event_field *) marker;
+	marker = marker + sizeof(event_field->event_size)
+		+ event_field->event_size;
+	size = marker - marker_start;
+
+	if ((event->event_type == 0) && (event_field->event_size == 0))
+		return 0;
+
+	return size;
+}
+
+static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
+{
+	struct tpm_bios_log *log = m->private;
+	void *addr = log->bios_event_log;
+	void *limit = log->bios_event_log_end;
+	struct tcg_pcr_event *event_header;
+	struct tcg_pcr_event2 *event;
+	int i;
+	size_t size = 0;
+
+	event_header = addr;
+
+	size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event)
+		+ event_header->event_size;
+
+
+	if (*pos == 0) {
+		if (addr + size < limit) {
+			if ((event_header->event_type == 0) &&
+					(event_header->event_size == 0))
+				return NULL;
+			return SEQ_START_TOKEN;
+		}
+	}
+
+	if (*pos > 0) {
+		addr += size;
+		event = addr;
+		size = calc_tpm2_event_size(event, event_header);
+		if ((addr + size >=  limit) || (size == 0))
+			return NULL;
+	}
+
+	/* read over *pos measurements */
+	for (i = 0; i < (*pos - 1); i++) {
+		event = addr;
+		size = calc_tpm2_event_size(event, event_header);
+
+		if ((addr + size >= limit) || (size == 0))
+			return NULL;
+		addr += size;
+	}
+
+	return addr;
+}
+
+static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
+		loff_t *pos)
+{
+	struct tcg_pcr_event *event_header;
+	struct tcg_pcr_event2 *event;
+	struct tpm_bios_log *log = m->private;
+	void *limit = log->bios_event_log_end;
+	void *marker;
+	size_t event_size = 0;
+
+	event_header = log->bios_event_log;
+
+	if (v == SEQ_START_TOKEN) {
+		event_size = sizeof(struct tcg_pcr_event)
+			- sizeof(event_header->event)
+			+ event_header->event_size;
+		marker = event_header;
+	} else {
+		event = v;
+		event_size = calc_tpm2_event_size(event, event_header);
+		if (event_size == 0)
+			return NULL;
+		marker =  event;
+	}
+
+	marker = marker + event_size;
+	if (marker >= limit)
+		return NULL;
+	v = marker;
+	event = v;
+
+	event_size = calc_tpm2_event_size(event, event_header);
+	if (((v + event_size) >= limit) || (event_size == 0))
+		return NULL;
+
+	(*pos)++;
+	return v;
+}
+
+static void tpm2_bios_measurements_stop(struct seq_file *m, void *v)
+{
+}
+
+static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
+{
+	struct tpm_bios_log *log = m->private;
+	struct tcg_pcr_event *event_header = log->bios_event_log;
+	struct tcg_pcr_event2 *event = v;
+	void *temp_ptr;
+	size_t size = 0;
+
+	if (v == SEQ_START_TOKEN) {
+
+		size = sizeof(struct tcg_pcr_event)
+			- sizeof(event_header->event)
+			+ event_header->event_size;
+
+		temp_ptr = event_header;
+
+		if (size > 0)
+			seq_write(m, temp_ptr, size);
+	} else {
+
+		size = calc_tpm2_event_size(event, event_header);
+
+		temp_ptr = event;
+		if (size > 0)
+			seq_write(m, temp_ptr, size);
+	}
+
+	return 0;
+}
+
+const struct seq_operations tpm2_binary_b_measurments_seqops = {
+	.start = tpm2_bios_measurements_start,
+	.next = tpm2_bios_measurements_next,
+	.stop = tpm2_bios_measurements_stop,
+	.show = tpm2_binary_bios_measurements_show,
+};
diff --git a/drivers/char/tpm/tpm_eventlog_init.c b/drivers/char/tpm/tpm_eventlog_init.c
index 038771a..9afeb3d 100644
--- a/drivers/char/tpm/tpm_eventlog_init.c
+++ b/drivers/char/tpm/tpm_eventlog_init.c
@@ -28,6 +28,7 @@ 
 #include <linux/slab.h>
 
 #include "tpm.h"
+#include "tpm2.h"
 #include "tpm_eventlog.h"
 
 static int tpm_bios_measurements_release(struct inode *inode,
@@ -94,6 +95,7 @@  int read_log(struct tpm_chip *chip)
 void tpm_bios_log_setup(struct tpm_chip *chip)
 {
 	const char *name = dev_name(&chip->dev);
+	void *seq_ops;
 	int rc = 0;
 
 	rc = read_log(chip);
@@ -108,23 +110,31 @@  void tpm_bios_log_setup(struct tpm_chip *chip)
 	chip->bios_dir[chip->bios_dir_count]->d_inode->i_private = chip;
 	chip->bios_dir_count++;
 
+	if (chip->flags & TPM_CHIP_FLAG_TPM2)
+		seq_ops = (void *)&tpm2_binary_b_measurments_seqops;
+	else
+		seq_ops = (void *)&tpm_binary_b_measurments_seqops;
+
+
 	chip->bios_dir[chip->bios_dir_count] =
 	    securityfs_create_file("binary_bios_measurements",
 				   S_IRUSR | S_IRGRP, chip->bios_dir[0],
-				   (void *)&tpm_binary_b_measurments_seqops,
+				   seq_ops,
 				   &tpm_bios_measurements_ops);
 	if (is_bad(chip->bios_dir[chip->bios_dir_count]))
 		goto err;
 	chip->bios_dir_count++;
 
-	chip->bios_dir[chip->bios_dir_count] =
-	    securityfs_create_file("ascii_bios_measurements",
-				   S_IRUSR | S_IRGRP, chip->bios_dir[0],
-				   (void *)&tpm_ascii_b_measurments_seqops,
-				   &tpm_bios_measurements_ops);
-	if (is_bad(chip->bios_dir[chip->bios_dir_count]))
-		goto err;
-	chip->bios_dir_count++;
+	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
+		chip->bios_dir[chip->bios_dir_count] =
+			securityfs_create_file("ascii_bios_measurements",
+					S_IRUSR | S_IRGRP, chip->bios_dir[0],
+					(void *)&tpm_ascii_b_measurments_seqops,
+					&tpm_bios_measurements_ops);
+		if (is_bad(chip->bios_dir[chip->bios_dir_count]))
+			goto err;
+		chip->bios_dir_count++;
+	}
 
 	return;
 
diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 4e4eed7..2fc58fe 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -15,12 +15,10 @@ 
  *
  */
 
-#include <linux/seq_file.h>
-#include <linux/fs.h>
-#include <linux/security.h>
-#include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/of_device.h>
 #include <linux/of.h>
+#include <linux/string.h>
 
 #include "tpm.h"
 #include "tpm_eventlog.h"
@@ -30,44 +28,60 @@  int read_log_of(struct tpm_chip *chip)
 	struct device_node *np;
 	const u32 *sizep;
 	const u64 *basep;
+	const struct of_device_id *of_id;
+	const char *compat;
+	u32 log_size;
 
 	if (chip->dev.of_node)
 		np = chip->dev.of_node;
 	if (!np) {
-		dev_dbg(&chip->dev, "%s: ERROR - IBMVTPM not supported\n",
+		dev_dbg(&chip->dev, "%s: ERROR - TPM not supported\n",
 			__func__);
 		return -ENODEV;
 	}
 
+	compat = of_get_property(np, "compatible", NULL);
+	if (compat == NULL) {
+		dev_dbg(&chip->dev, "%s: ERROR - Compatible device not found",
+			__func__);
+		return -EIO;
+	}
+
 	sizep = of_get_property(np, "linux,sml-size", NULL);
 	if (sizep == NULL) {
 		dev_dbg(&chip->dev, "%s: ERROR - SML size not found\n",
 			__func__);
-		goto cleanup_eio;
+		return -EIO;
 	}
 	if (*sizep == 0) {
 		dev_dbg(&chip->dev, "%s: ERROR - event log area empty\n",
 			__func__);
-		goto cleanup_eio;
+		return -EIO;
 	}
 
+	if (!strcasecmp(compat, "IBM,vtpm"))
+		log_size = *sizep;
+	else
+		log_size = be32_to_cpup(sizep);
+
 	basep = of_get_property(np, "linux,sml-base", NULL);
 	if (basep == NULL) {
 		dev_dbg(&chip->dev, "%s: ERROR - SML not found\n", __func__);
-		goto cleanup_eio;
+		return -EIO;
 	}
 
-	chip->log.bios_event_log = kmalloc(*sizep, GFP_KERNEL);
+	chip->log.bios_event_log = kmalloc(log_size, GFP_KERNEL);
 	if (!chip->log.bios_event_log) {
 		return -ENOMEM;
 	}
 
-	chip->log.bios_event_log_end = chip->log.bios_event_log + *sizep;
+	chip->log.bios_event_log_end = chip->log.bios_event_log + log_size;
 
-	memcpy(chip->log.bios_event_log, __va(*basep), *sizep);
+	if (!strcasecmp(compat, "IBM,vtpm"))
+		memcpy(chip->log.bios_event_log, __va(*basep), log_size);
+	else
+		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
+				log_size);
 
 	return 0;
-
-cleanup_eio:
-	return -EIO;
 }