tpm: Fix handling of missing event log

The event log is an optional firmware feature, if the firmware
does not support it then the securityfs files should not be created
and no other notification given.

- Uniformly return -ENODEV from the tpm_bios_log_setup cone if
  no event log is detected.
- Check in ACPI if this node was discovered via ACPI.
- Improve the check in OF to make sure there is a parent and to
  fail detection if the two log properties are not declared
- Pass through all other error codes instead of filtering just some

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 3f27753..7a48691 100644 (file)
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -346,7 +346,7 @@ int tpm_chip_register(struct tpm_chip *chip)
        tpm_sysfs_add_device(chip);
 
        rc = tpm_bios_log_setup(chip);
-       if (rc == -ENODEV)
+       if (rc != 0 && rc != -ENODEV)
                return rc;
 
        tpm_add_ppi(chip);

diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c
index 0cb43ef..b7718c9 100644 (file)
--- a/drivers/char/tpm/tpm_acpi.c
+++ b/drivers/char/tpm/tpm_acpi.c
@@ -56,12 +56,18 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
 
        log = &chip->log;
 
+       /* Unfortuntely ACPI does not associate the event log with a specific
+        * TPM, like PPI. Thus all ACPI TPMs will read the same log.
+        */
+       if (!chip->acpi_dev_handle)
+               return -ENODEV;
+
        /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
        status = acpi_get_table(ACPI_SIG_TCPA, 1,
                                (struct acpi_table_header **)&buff);
 
        if (ACPI_FAILURE(status))
-               return -EIO;
+               return -ENODEV;
 
        switch(buff->platform_class) {
        case BIOS_SERVER:

diff --git a/drivers/char/tpm/tpm_eventlog.c b/drivers/char/tpm/tpm_eventlog.c
index 34f0921..c73f88c 100644 (file)
--- a/drivers/char/tpm/tpm_eventlog.c
+++ b/drivers/char/tpm/tpm_eventlog.c
@@ -368,14 +368,21 @@ static int tpm_read_log(struct tpm_chip *chip)
        }
 
        rc = tpm_read_log_acpi(chip);
-       if ((rc == 0) || (rc == -ENOMEM))
+       if (rc != -ENODEV)
                return rc;
 
-       rc = tpm_read_log_of(chip);
-
-       return rc;
+       return tpm_read_log_of(chip);
 }
 
+/*
+ * tpm_bios_log_setup() - Read the event log from the firmware
+ * @chip: TPM chip to use.
+ *
+ * If an event log is found then the securityfs files are setup to
+ * export it to userspace, otherwise nothing is done.
+ *
+ * Returns -ENODEV if the firmware has no event log.
+ */
 int tpm_bios_log_setup(struct tpm_chip *chip)
 {
        const char *name = dev_name(&chip->dev);
@@ -386,15 +393,8 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
                return 0;
 
        rc = tpm_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;
-       }
+       if (rc)
+               return rc;
 
        cnt = 0;
        chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);

diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 36df9df..7dee42d 100644 (file)
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -29,13 +29,16 @@ int tpm_read_log_of(struct tpm_chip *chip)
        struct tpm_bios_log *log;
 
        log = &chip->log;
-       if (chip->dev.parent->of_node)
+       if (chip->dev.parent && chip->dev.parent->of_node)
                np = chip->dev.parent->of_node;
        else
                return -ENODEV;
 
        sizep = of_get_property(np, "linux,sml-size", NULL);
-       if (sizep == NULL)
+       basep = of_get_property(np, "linux,sml-base", NULL);
+       if (sizep == NULL && basep == NULL)
+               return -ENODEV;
+       if (sizep == NULL || basep == NULL)
                return -EIO;
 
        if (*sizep == 0) {
@@ -43,10 +46,6 @@ int tpm_read_log_of(struct tpm_chip *chip)
                return -EIO;
        }
 
-       basep = of_get_property(np, "linux,sml-base", NULL);
-       if (basep == NULL)
-               return -EIO;
-
        log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
        if (!log->bios_event_log)
                return -ENOMEM;