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Subject[PATCH RFC] tpm, tpm_tis: detect TPM2 devices
Date
It turned out that the root cause in b371616b8 was not entirely correct
for https://bugzilla.kernel.org/show_bug.cgi?id=98181.

All TPM 2.0 FIFO and CRB devices have the same HID. For FIFO devices
the start method is 6 as it is defined in

http://www.trustedcomputinggroup.org/resources/tcg_acpi_specification

This patch changes FIFO and CRB drivers so that they check start method
value and initialize only if the start method has a proper value for
that particular interface.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
drivers/char/tpm/tpm.h | 7 +++++++
drivers/char/tpm/tpm_crb.c | 20 +++++---------------
drivers/char/tpm/tpm_tis.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 55 insertions(+), 17 deletions(-)

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index f8319a0..39be5ac 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -115,6 +115,13 @@ enum tpm2_startup_types {
TPM2_SU_STATE = 0x0001,
};

+enum tpm2_start_method {
+ TPM2_START_ACPI = 2,
+ TPM2_START_FIFO = 6,
+ TPM2_START_CRB = 7,
+ TPM2_START_CRB_WITH_ACPI = 8,
+};
+
struct tpm_chip;

struct tpm_vendor_specific {
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 1267322..b4564b6 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -34,12 +34,6 @@ enum crb_defaults {
CRB_ACPI_START_INDEX = 1,
};

-enum crb_start_method {
- CRB_SM_ACPI_START = 2,
- CRB_SM_CRB = 7,
- CRB_SM_CRB_WITH_ACPI_START = 8,
-};
-
struct acpi_tpm2 {
struct acpi_table_header hdr;
u16 platform_class;
@@ -233,13 +227,9 @@ static int crb_acpi_add(struct acpi_device *device)
return -ENODEV;
}

- /* At least some versions of AMI BIOS have a bug that TPM2 table has
- * zero address for the control area and therefore we must fail.
- */
- if (!buf->control_area_pa) {
- dev_err(dev, "TPM2 ACPI table has a zero address for the control area\n");
- return -EINVAL;
- }
+ /* Should the FIFO driver handle this? */
+ if (buf->start_method == TPM2_START_FIFO)
+ return -ENODEV;

if (buf->hdr.length < sizeof(struct acpi_tpm2)) {
dev_err(dev, "TPM2 ACPI table has wrong size");
@@ -259,11 +249,11 @@ static int crb_acpi_add(struct acpi_device *device)
* report only ACPI start but in practice seems to require both
* ACPI start and CRB start.
*/
- if (sm == CRB_SM_CRB || sm == CRB_SM_CRB_WITH_ACPI_START ||
+ if (sm == TPM2_START_CRB || sm == TPM2_START_FIFO ||
!strcmp(acpi_device_hid(device), "MSFT0101"))
priv->flags |= CRB_FL_CRB_START;

- if (sm == CRB_SM_ACPI_START || sm == CRB_SM_CRB_WITH_ACPI_START)
+ if (sm == TPM2_START_ACPI || sm == TPM2_START_CRB_WITH_ACPI)
priv->flags |= CRB_FL_ACPI_START;

priv->cca = (struct crb_control_area __iomem *)
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index f2dffa7..4760804 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -28,6 +28,7 @@
#include <linux/wait.h>
#include <linux/acpi.h>
#include <linux/freezer.h>
+#include <acpi/actbl2.h>
#include "tpm.h"

enum tis_access {
@@ -91,7 +92,7 @@ struct priv_data {
};

#if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
-static int is_itpm(struct pnp_dev *dev)
+static int has_hid(struct pnp_dev *dev, const char *hid)
{
struct acpi_device *acpi = pnp_acpi_device(dev);
struct acpi_hardware_id *id;
@@ -100,17 +101,49 @@ static int is_itpm(struct pnp_dev *dev)
return 0;

list_for_each_entry(id, &acpi->pnp.ids, list) {
- if (!strcmp("INTC0102", id->id))
+ if (!strcmp(hid, id->id))
return 1;
}

return 0;
}
+
+static inline int is_itpm(struct pnp_dev *dev)
+{
+ return has_hid(dev, "INTC0102");
+}
+
+static inline int validate_pnp_dev(struct pnp_dev *dev)
+{
+ struct acpi_table_tpm2 *tbl;
+ acpi_status st;
+
+ if (!has_hid(dev, "MSFT0101"))
+ return 0;
+
+ st = acpi_get_table(ACPI_SIG_TPM2, 1,
+ (struct acpi_table_header **) &tbl);
+ if (ACPI_FAILURE(st)) {
+ dev_err(&dev->dev, "failed to get TPM2 ACPI table\n");
+ return -ENODEV;
+ }
+
+ /* Should the CRB driver handle this? */
+ if (le32_to_cpu(tbl->start_method) != TPM2_START_FIFO)
+ return -ENODEV:
+
+ retuurn 0;
+}
#else
static inline int is_itpm(struct pnp_dev *dev)
{
return 0;
}
+
+static inline int validate_pnp_dev(struct pnp_dev *dev)
+{
+ return 0;
+}
#endif

/* Before we attempt to access the TPM we must see that the valid bit is set.
@@ -893,6 +926,11 @@ static int tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
resource_size_t start, len;
unsigned int irq = 0;
acpi_handle acpi_dev_handle = NULL;
+ int ret;
+
+ ret = validate_pnp_dev(pnp_dev);
+ if (ret)
+ return ret;

start = pnp_mem_start(pnp_dev, 0);
len = pnp_mem_len(pnp_dev, 0);
@@ -921,6 +959,9 @@ static struct pnp_device_id tpm_pnp_tbl[] = {
{"BCM0102", 0}, /* Broadcom */
{"NSC1200", 0}, /* National */
{"ICO0102", 0}, /* Intel */
+#ifdef CONFIG_ACPI
+ {"MSFT0101", 0}, /* TPM 2.0 */
+#endif
/* Add new here */
{"", 0}, /* User Specified */
{"", 0} /* Terminator */
--
2.5.0


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