Commit 748935ee authored by Nayna Jain's avatar Nayna Jain Committed by Jarkko Sakkinen
Browse files

tpm: have event log use the tpm_chip 



Move the backing memory for the event log into tpm_chip and push
the tpm_chip into read_log. This optimizes read_log processing by
only doing it once and prepares things for the next patches in the
series which require the tpm_chip to locate the event log via
ACPI and OF handles instead of searching.

This is straightfoward except for the issue of passing a kref through
i_private with securityfs. Since securityfs_remove does not have any
removal fencing like sysfs we use the inode lock to safely get a
kref on the tpm_chip.

Suggested-by: default avatarJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: default avatarNayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent 7518a21a

drivers/char/tpm/tpm-chip.c

+2 −1
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ static void tpm_dev_release(struct device *dev) 
	idr_remove(&dev_nums_idr, chip->dev_num);

	mutex_unlock(&idr_lock);



	kfree(chip->log.bios_event_log);

	kfree(chip);

}
@@ -345,7 +346,7 @@ int tpm_chip_register(struct tpm_chip *chip) 
	tpm_sysfs_add_device(chip);



	rc = tpm_bios_log_setup(chip);

	if (rc)

	if (rc == -ENODEV)

		return rc;



	tpm_add_ppi(chip);

drivers/char/tpm/tpm.h

+11 −0
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ 
#include <linux/cdev.h>

#include <linux/highmem.h>



#include "tpm_eventlog.h"



enum tpm_const {

	TPM_MINOR = 224,	/* officially assigned */

	TPM_BUFSIZE = 4096,
@@ -146,6 +148,11 @@ enum tpm_chip_flags { 
	TPM_CHIP_FLAG_HAVE_TIMEOUTS	= BIT(4),

};



struct tpm_chip_seqops {

	struct tpm_chip *chip;

	const struct seq_operations *seqops;

};



struct tpm_chip {

	struct device dev;

	struct cdev cdev;
@@ -157,6 +164,10 @@ struct tpm_chip { 
	struct rw_semaphore ops_sem;

	const struct tpm_class_ops *ops;



	struct tpm_bios_log log;

	struct tpm_chip_seqops bin_log_seqops;

	struct tpm_chip_seqops ascii_log_seqops;



	unsigned int flags;



	int dev_num;		/* /dev/tpm# */

drivers/char/tpm/tpm_acpi.c

+11 −4
Original line number Diff line number Diff line
@@ -45,13 +45,15 @@ struct acpi_tcpa { 
};



/* read binary bios log */

int read_log(struct tpm_bios_log *log)

int read_log(struct tpm_chip *chip)

{

	struct acpi_tcpa *buff;

	acpi_status status;

	void __iomem *virt;

	u64 len, start;

	struct tpm_bios_log *log;



	log = &chip->log;

	if (log->bios_event_log != NULL) {

		printk(KERN_ERR

		       "%s: ERROR - Eventlog already initialized\n",
@@ -97,13 +99,18 @@ int read_log(struct tpm_bios_log *log) 


	virt = acpi_os_map_iomem(start, len);

	if (!virt) {

		kfree(log->bios_event_log);

		printk("%s: ERROR - Unable to map memory\n", __func__);

		return -EIO;

		goto err;

	}



	memcpy_fromio(log->bios_event_log, virt, len);



	acpi_os_unmap_iomem(virt, len);

	return 0;



err:

	kfree(log->bios_event_log);

	log->bios_event_log = NULL;

	return -EIO;



}

drivers/char/tpm/tpm_eventlog.c

+56 −30
Original line number Diff line number Diff line
@@ -73,7 +73,8 @@ static const char* tcpa_pc_event_id_strings[] = { 
static void *tpm_bios_measurements_start(struct seq_file *m, loff_t *pos)

{

	loff_t i;

	struct tpm_bios_log *log = m->private;

	struct tpm_chip *chip = m->private;

	struct tpm_bios_log *log = &chip->log;

	void *addr = log->bios_event_log;

	void *limit = log->bios_event_log_end;

	struct tcpa_event *event;
@@ -120,7 +121,8 @@ static void *tpm_bios_measurements_next(struct seq_file *m, void *v, 
					loff_t *pos)

{

	struct tcpa_event *event = v;

	struct tpm_bios_log *log = m->private;

	struct tpm_chip *chip = m->private;

	struct tpm_bios_log *log = &chip->log;

	void *limit = log->bios_event_log_end;

	u32 converted_event_size;

	u32 converted_event_type;
@@ -261,13 +263,10 @@ static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v) 
static int tpm_bios_measurements_release(struct inode *inode,

					 struct file *file)

{

	struct seq_file *seq = file->private_data;

	struct tpm_bios_log *log = seq->private;

	struct seq_file *seq = (struct seq_file *)file->private_data;

	struct tpm_chip *chip = (struct tpm_chip *)seq->private;



	if (log) {

		kfree(log->bios_event_log);

		kfree(log);

	}

	put_device(&chip->dev);



	return seq_release(inode, file);

}
@@ -323,33 +322,30 @@ static int tpm_bios_measurements_open(struct inode *inode, 
					    struct file *file)

{

	int err;

	struct tpm_bios_log *log;

	struct seq_file *seq;

	const struct seq_operations *seqops =

		(const struct seq_operations *)inode->i_private;



	log = kzalloc(sizeof(struct tpm_bios_log), GFP_KERNEL);

	if (!log)

		return -ENOMEM;



	if ((err = read_log(log)))

		goto out_free;

	struct tpm_chip_seqops *chip_seqops;

	const struct seq_operations *seqops;

	struct tpm_chip *chip;



	inode_lock(inode);

	if (!inode->i_private) {

		inode_unlock(inode);

		return -ENODEV;

	}

	chip_seqops = (struct tpm_chip_seqops *)inode->i_private;

	seqops = chip_seqops->seqops;

	chip = chip_seqops->chip;

	get_device(&chip->dev);

	inode_unlock(inode);



	/* now register seq file */

	err = seq_open(file, seqops);

	if (!err) {

		seq = file->private_data;

		seq->private = log;

	} else {

		goto out_free;

		seq->private = chip;

	}



out:

	return err;

out_free:

	kfree(log->bios_event_log);

	kfree(log);

	goto out;

}



static const struct file_operations tpm_bios_measurements_ops = {
@@ -363,10 +359,22 @@ int tpm_bios_log_setup(struct tpm_chip *chip) 
{

	const char *name = dev_name(&chip->dev);

	unsigned int cnt;

	int rc = 0;



	if (chip->flags & TPM_CHIP_FLAG_TPM2)

		return 0;



	rc = read_log(chip);

	/*

	 * read_log failure means event log is not supported except for ENOMEM.

	 */

	if (rc < 0) {

		if (rc == -ENOMEM)

			return -ENODEV;

		else

			return rc;

	}



	cnt = 0;

	chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);

	/* NOTE: securityfs_create_dir can return ENODEV if securityfs is
@@ -376,19 +384,25 @@ int tpm_bios_log_setup(struct tpm_chip *chip) 
		goto err;

	cnt++;



	chip->bin_log_seqops.chip = chip;

	chip->bin_log_seqops.seqops = &tpm_binary_b_measurements_seqops;



	chip->bios_dir[cnt] =

	    securityfs_create_file("binary_bios_measurements",

				   0440, chip->bios_dir[0],

				   (void *)&tpm_binary_b_measurements_seqops,

				   (void *)&chip->bin_log_seqops,

				   &tpm_bios_measurements_ops);

	if (IS_ERR(chip->bios_dir[cnt]))

		goto err;

	cnt++;



	chip->ascii_log_seqops.chip = chip;

	chip->ascii_log_seqops.seqops = &tpm_ascii_b_measurements_seqops;



	chip->bios_dir[cnt] =

	    securityfs_create_file("ascii_bios_measurements",

				   0440, chip->bios_dir[0],

				   (void *)&tpm_ascii_b_measurements_seqops,

				   (void *)&chip->ascii_log_seqops,

				   &tpm_bios_measurements_ops);

	if (IS_ERR(chip->bios_dir[cnt]))

		goto err;
@@ -405,7 +419,19 @@ err: 
void tpm_bios_log_teardown(struct tpm_chip *chip)

{

	int i;

	struct inode *inode;



	for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--)

	/* securityfs_remove currently doesn't take care of handling sync

	 * between removal and opening of pseudo files. To handle this, a

	 * workaround is added by making i_private = NULL here during removal

	 * and to check it during open(), both within inode_lock()/unlock().

	 * This design ensures that open() either safely gets kref or fails.

	 */

	for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {

		inode = d_inode(chip->bios_dir[i]);

		inode_lock(inode);

		inode->i_private = NULL;

		inode_unlock(inode);

		securityfs_remove(chip->bios_dir[i]);

	}

}

drivers/char/tpm/tpm_eventlog.h

+1 −1
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ enum tcpa_pc_event_ids { 
	HOST_TABLE_OF_DEVICES,

};



int read_log(struct tpm_bios_log *log);

int read_log(struct tpm_chip *chip);



#if defined(CONFIG_TCG_IBMVTPM) || defined(CONFIG_TCG_IBMVTPM_MODULE) || \

	defined(CONFIG_ACPI)

CRA Git | Maintained and supported by SUSTech CRA and CCSE