tpm: fix raciness of PPI interface lookup

Traversal of the ACPI device tree was not done right. PPI interface
should be looked up only from the ACPI device that is the platform
device for the TPM. This could cause problems with systems with
two TPM chips such as 4th gen Intel systems.

In addition, added the missing license and copyright platter to
the tpm_ppi.c.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jasob Gunthorpe <jason.gunthorpe@obsidianresearch.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

1 files changed, 87 insertions, 54 deletions

diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index 61dcc8011ec7..af48c56f642f 100644
--- a/drivers/char/tpm/tpm_ppi.c
+++ b/drivers/char/tpm/tpm_ppi.c
@@ -1,3 +1,22 @@
+/*
+ * Copyright (C) 2012-2014 Intel Corporation
+ *
+ * Authors:
+ * Xiaoyan Zhang <xiaoyan.zhang@intel.com>
+ * Jiang Liu <jiang.liu@linux.intel.com>
+ * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * This file contains implementation of the sysfs interface for PPI.
+ *
+ * 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; version 2
+ * of the License.
+ */
+
+
 #include <linux/acpi.h>
 #include "tpm.h"
 
@@ -12,7 +31,6 @@
 #define PPI_TPM_REQ_MAX		22
 #define PPI_VS_REQ_START	128
 #define PPI_VS_REQ_END		255
-#define PPI_VERSION_LEN		3
 
 static const u8 tpm_ppi_uuid[] = {
 	0xA6, 0xFA, 0xDD, 0x3D,
@@ -22,45 +40,22 @@ static const u8 tpm_ppi_uuid[] = {
 	0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
 };
 
-static char tpm_ppi_version[PPI_VERSION_LEN + 1];
-static acpi_handle tpm_ppi_handle;
-
-static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
-				void **return_value)
-{
-	union acpi_object *obj;
-
-	if (!acpi_check_dsm(handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
-			    1 << TPM_PPI_FN_VERSION))
-		return AE_OK;
-
-	/* Cache version string */
-	obj = acpi_evaluate_dsm_typed(handle, tpm_ppi_uuid,
-				      TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
-				      NULL, ACPI_TYPE_STRING);
-	if (obj) {
-		strlcpy(tpm_ppi_version, obj->string.pointer,
-			PPI_VERSION_LEN + 1);
-		ACPI_FREE(obj);
-	}
-
-	*return_value = handle;
-
-	return AE_CTRL_TERMINATE;
-}
-
 static inline union acpi_object *
-tpm_eval_dsm(int func, acpi_object_type type, union acpi_object *argv4)
+tpm_eval_dsm(acpi_handle ppi_handle, int func, acpi_object_type type,
+	     union acpi_object *argv4)
 {
-	BUG_ON(!tpm_ppi_handle);
-	return acpi_evaluate_dsm_typed(tpm_ppi_handle, tpm_ppi_uuid,
-				       TPM_PPI_REVISION_ID, func, argv4, type);
+	BUG_ON(!ppi_handle);
+	return acpi_evaluate_dsm_typed(ppi_handle, tpm_ppi_uuid,
+				       TPM_PPI_REVISION_ID,
+				       func, argv4, type);
 }
 
 static ssize_t tpm_show_ppi_version(struct device *dev,
 				    struct device_attribute *attr, char *buf)
 {
-	return scnprintf(buf, PAGE_SIZE, "%s\n", tpm_ppi_version);
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
 }
 
 static ssize_t tpm_show_ppi_request(struct device *dev,
@@ -68,8 +63,10 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
 {
 	ssize_t size = -EINVAL;
 	union acpi_object *obj;
+	struct tpm_chip *chip = dev_get_drvdata(dev);
 
-	obj = tpm_eval_dsm(TPM_PPI_FN_GETREQ, ACPI_TYPE_PACKAGE, NULL);
+	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
+			   ACPI_TYPE_PACKAGE, NULL);
 	if (!obj)
 		return -ENXIO;
 
@@ -103,14 +100,15 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
 	int func = TPM_PPI_FN_SUBREQ;
 	union acpi_object *obj, tmp;
 	union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);
+	struct tpm_chip *chip = dev_get_drvdata(dev);
 
 	/*
 	 * the function to submit TPM operation request to pre-os environment
 	 * is updated with function index from SUBREQ to SUBREQ2 since PPI
 	 * version 1.1
 	 */
-	if (acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
-			   1 << TPM_PPI_FN_SUBREQ2))
+	if (acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
+			   TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_SUBREQ2))
 		func = TPM_PPI_FN_SUBREQ2;
 
 	/*
@@ -119,7 +117,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
 	 * string/package type. For PPI version 1.0 and 1.1, use buffer type
 	 * for compatibility, and use package type since 1.2 according to spec.
 	 */
-	if (strcmp(tpm_ppi_version, "1.2") < 0) {
+	if (strcmp(chip->ppi_version, "1.2") < 0) {
 		if (sscanf(buf, "%d", &req) != 1)
 			return -EINVAL;
 		argv4.type = ACPI_TYPE_BUFFER;
@@ -131,7 +129,8 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
 			return -EINVAL;
 	}
 
-	obj = tpm_eval_dsm(func, ACPI_TYPE_INTEGER, &argv4);
+	obj = tpm_eval_dsm(chip->acpi_dev_handle, func, ACPI_TYPE_INTEGER,
+			   &argv4);
 	if (!obj) {
 		return -ENXIO;
 	} else {
@@ -157,6 +156,7 @@ static ssize_t tpm_show_ppi_transition_action(struct device *dev,
 		.buffer.length = 0,
 		.buffer.pointer = NULL
 	};
+	struct tpm_chip *chip = dev_get_drvdata(dev);
 
 	static char *info[] = {
 		"None",
@@ -171,9 +171,10 @@ static ssize_t tpm_show_ppi_transition_action(struct device *dev,
 	 * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
 	 * compatibility, define params[3].type as buffer, if PPI version < 1.2
 	 */
-	if (strcmp(tpm_ppi_version, "1.2") < 0)
+	if (strcmp(chip->ppi_version, "1.2") < 0)
 		obj = &tmp;
-	obj = tpm_eval_dsm(TPM_PPI_FN_GETACT, ACPI_TYPE_INTEGER, obj);
+	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETACT,
+			   ACPI_TYPE_INTEGER, obj);
 	if (!obj) {
 		return -ENXIO;
 	} else {
@@ -196,8 +197,10 @@ static ssize_t tpm_show_ppi_response(struct device *dev,
 	acpi_status status = -EINVAL;
 	union acpi_object *obj, *ret_obj;
 	u64 req, res;
+	struct tpm_chip *chip = dev_get_drvdata(dev);
 
-	obj = tpm_eval_dsm(TPM_PPI_FN_GETRSP, ACPI_TYPE_PACKAGE, NULL);
+	obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
+			   ACPI_TYPE_PACKAGE, NULL);
 	if (!obj)
 		return -ENXIO;
 
@@ -248,7 +251,8 @@ cleanup:
 	return status;
 }
 
-static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
+static ssize_t show_ppi_operations(acpi_handle dev_handle, char *buf, u32 start,
+				   u32 end)
 {
 	int i;
 	u32 ret;
@@ -264,14 +268,15 @@ static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
 		"User not required",
 	};
 
-	if (!acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
+	if (!acpi_check_dsm(dev_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
 			    1 << TPM_PPI_FN_GETOPR))
 		return -EPERM;
 
 	tmp.integer.type = ACPI_TYPE_INTEGER;
 	for (i = start; i <= end; i++) {
 		tmp.integer.value = i;
-		obj = tpm_eval_dsm(TPM_PPI_FN_GETOPR, ACPI_TYPE_INTEGER, &argv);
+		obj = tpm_eval_dsm(dev_handle, TPM_PPI_FN_GETOPR,
+				   ACPI_TYPE_INTEGER, &argv);
 		if (!obj) {
 			return -ENOMEM;
 		} else {
@@ -291,14 +296,20 @@ static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
 					   struct device_attribute *attr,
 					   char *buf)
 {
-	return show_ppi_operations(buf, 0, PPI_TPM_REQ_MAX);
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+
+	return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
+				   PPI_TPM_REQ_MAX);
 }
 
 static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
 					  struct device_attribute *attr,
 					  char *buf)
 {
-	return show_ppi_operations(buf, PPI_VS_REQ_START, PPI_VS_REQ_END);
+	struct tpm_chip *chip = dev_get_drvdata(dev);
+
+	return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
+				   PPI_VS_REQ_END);
 }
 
 static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
@@ -323,16 +334,38 @@ static struct attribute_group ppi_attr_grp = {
 	.attrs = ppi_attrs
 };
 
-int tpm_add_ppi(struct kobject *parent)
+int tpm_add_ppi(struct tpm_chip *chip)
 {
-	/* Cache TPM ACPI handle and version string */
-	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
-			    ppi_callback, NULL, NULL, &tpm_ppi_handle);
-	return tpm_ppi_handle ? sysfs_create_group(parent, &ppi_attr_grp) : 0;
+	union acpi_object *obj;
+	int rc;
+
+	if (!chip->acpi_dev_handle)
+		return 0;
+
+	if (!acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
+			    TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_VERSION))
+		return 0;
+
+	/* Cache PPI version string. */
+	obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, tpm_ppi_uuid,
+				      TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
+				      NULL, ACPI_TYPE_STRING);
+	if (obj) {
+		strlcpy(chip->ppi_version, obj->string.pointer,
+			sizeof(chip->ppi_version));
+		ACPI_FREE(obj);
+	}
+
+	rc = sysfs_create_group(&chip->dev->kobj, &ppi_attr_grp);
+
+	if (!rc)
+		chip->flags |= TPM_CHIP_FLAG_PPI;
+
+	return rc;
 }
 
-void tpm_remove_ppi(struct kobject *parent)
+void tpm_remove_ppi(struct tpm_chip *chip)
 {
-	if (tpm_ppi_handle)
-		sysfs_remove_group(parent, &ppi_attr_grp);
+	if (chip->flags & TPM_CHIP_FLAG_PPI)
+		sysfs_remove_group(&chip->dev->kobj, &ppi_attr_grp);
 }