[PATCH v6 5/9] tpm: have event log use the tpm_chip
From: Nayna Jain
Date: Mon Nov 14 2016 - 05:02:49 EST
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: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Nayna Jain <nayna@xxxxxxxxxxxxxxxxxx>
---
drivers/char/tpm/tpm-chip.c | 3 +-
drivers/char/tpm/tpm.h | 11 ++++++
drivers/char/tpm/tpm_acpi.c | 15 +++++--
drivers/char/tpm/tpm_eventlog.c | 88 ++++++++++++++++++++++++++---------------
drivers/char/tpm/tpm_eventlog.h | 2 +-
drivers/char/tpm/tpm_of.c | 4 +-
6 files changed, 85 insertions(+), 38 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 250a651..3f27753 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -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);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 9d69580..1ae9768 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -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# */
diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c
index 565a947..01dfb35 100644
--- a/drivers/char/tpm/tpm_acpi.c
+++ b/drivers/char/tpm/tpm_acpi.c
@@ -9,7 +9,7 @@
*
* Maintained by: <tpmdd-devel@xxxxxxxxxxxxxxxxxxxxx>
*
- * Access to the eventlog extended by the TCG BIOS of PC platform
+ * Access to the event log extended by the TCG BIOS of PC platform
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -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;
+
}
diff --git a/drivers/char/tpm/tpm_eventlog.c b/drivers/char/tpm/tpm_eventlog.c
index 57ac862..f8c42fe 100644
--- a/drivers/char/tpm/tpm_eventlog.c
+++ b/drivers/char/tpm/tpm_eventlog.c
@@ -11,7 +11,7 @@
*
* Maintained by: <tpmdd-devel@xxxxxxxxxxxxxxxxxxxxx>
*
- * Access to the eventlog created by a system's firmware / BIOS
+ * Access to the event log created by a system's firmware / BIOS
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -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 = {
@@ -372,29 +368,47 @@ 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);
if (is_bad(chip->bios_dir[cnt]))
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_bad(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_bad(chip->bios_dir[cnt]))
goto err;
@@ -411,7 +425,19 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
void tpm_bios_log_teardown(struct tpm_chip *chip)
{
int i;
-
- for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--)
+ struct inode *inode;
+
+ /* 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]);
+ }
}
diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h
index fd3357e..6df2f8e 100644
--- a/drivers/char/tpm/tpm_eventlog.h
+++ b/drivers/char/tpm/tpm_eventlog.h
@@ -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)
diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 570f30c..68d891a 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -20,12 +20,14 @@
#include "tpm.h"
#include "tpm_eventlog.h"
-int read_log(struct tpm_bios_log *log)
+int read_log(struct tpm_chip *chip)
{
struct device_node *np;
const u32 *sizep;
const u64 *basep;
+ struct tpm_bios_log *log;
+ log = &chip->log;
if (log->bios_event_log != NULL) {
pr_err("%s: ERROR - Eventlog already initialized\n", __func__);
return -EFAULT;
--
2.5.0