1 files changed, 86 insertions, 59 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 379c5d465579..187bcdaf7bf6 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -119,17 +119,57 @@ out:
 }
 
 #define TPM_DIGEST_SIZE 20
-#define CAP_PCR_RESULT_SIZE 18
-static const u8 cap_pcr[] = {
+#define TPM_ERROR_SIZE 10
+#define TPM_RET_CODE_IDX 6
+#define TPM_GET_CAP_RET_SIZE_IDX 10
+#define TPM_GET_CAP_RET_UINT32_1_IDX 14
+#define TPM_GET_CAP_RET_UINT32_2_IDX 18
+#define TPM_GET_CAP_RET_UINT32_3_IDX 22
+#define TPM_GET_CAP_RET_UINT32_4_IDX 26
+
+#define TPM_CAP_IDX 13
+#define TPM_CAP_SUBCAP_IDX 21
+
+enum tpm_capabilities {
+        TPM_CAP_PROP = 5,
+};
+
+enum tpm_sub_capabilities {
+        TPM_CAP_PROP_PCR = 0x1,
+        TPM_CAP_PROP_MANUFACTURER = 0x3,
+};
+
+/*
+ * This is a semi generic GetCapability command for use
+ * with the capability type TPM_CAP_PROP or TPM_CAP_FLAG
+ * and their associated sub_capabilities.
+ */
+
+static const u8 tpm_cap[] = {
         0, 193,                 /* TPM_TAG_RQU_COMMAND */
         0, 0, 0, 22,            /* length */
         0, 0, 0, 101,           /* TPM_ORD_GetCapability */
-        0, 0, 0, 5,
-        0, 0, 0, 4,
-        0, 0, 1, 1
+        0, 0, 0, 0,             /* TPM_CAP_<TYPE> */
+        0, 0, 0, 4,             /* TPM_CAP_SUB_<TYPE> size */
+        0, 0, 1, 0              /* TPM_CAP_SUB_<TYPE> */
 };
 
-#define READ_PCR_RESULT_SIZE 30
+static ssize_t transmit_cmd(struct tpm_chip *chip, u8 *data, int len,
+                            char *desc)
+{
+        int err;
+
+        len = tpm_transmit(chip, data, len);
+        if (len <  0)
+                return len;
+        if (len == TPM_ERROR_SIZE) {
+                err = be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX)));
+                dev_dbg(chip->dev, "A TPM error (%d) occurred %s\n", err, desc);
+                return err;
+        }
+        return 0;
+}
+
 static const u8 pcrread[] = {
         0, 193,                 /* TPM_TAG_RQU_COMMAND */
         0, 0, 0, 14,            /* length */
@@ -140,8 +180,8 @@ static const u8 pcrread[] = {
 ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
                       char *buf)
 {
-        u8 data[READ_PCR_RESULT_SIZE];
-        ssize_t len;
+        u8 data[30];
+        ssize_t rc;
         int i, j, num_pcrs;
         __be32 index;
         char *str = buf;
@@ -150,29 +190,24 @@ ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
         if (chip == NULL)
                 return -ENODEV;
 
-        memcpy(data, cap_pcr, sizeof(cap_pcr));
-        if ((len = tpm_transmit(chip, data, sizeof(data)))
-            < CAP_PCR_RESULT_SIZE) {
-                dev_dbg(chip->dev, "A TPM error (%d) occurred "
-                                "attempting to determine the number of PCRS\n",
-                        be32_to_cpu(*((__be32 *) (data + 6))));
+        memcpy(data, tpm_cap, sizeof(tpm_cap));
+        data[TPM_CAP_IDX] = TPM_CAP_PROP;
+        data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_PCR;
+
+        rc = transmit_cmd(chip, data, sizeof(data),
+                        "attempting to determine the number of PCRS");
+        if (rc)
                 return 0;
-        }
 
         num_pcrs = be32_to_cpu(*((__be32 *) (data + 14)));
-
         for (i = 0; i < num_pcrs; i++) {
                 memcpy(data, pcrread, sizeof(pcrread));
                 index = cpu_to_be32(i);
                 memcpy(data + 10, &index, 4);
-                if ((len = tpm_transmit(chip, data, sizeof(data)))
-                    < READ_PCR_RESULT_SIZE){
-                        dev_dbg(chip->dev, "A TPM error (%d) occurred"
-                                " attempting to read PCR %d of %d\n",
-                                be32_to_cpu(*((__be32 *) (data + 6))),
-                                i, num_pcrs);
+                rc = transmit_cmd(chip, data, sizeof(data),
+                                "attempting to read a PCR");
+                if (rc)
                         goto out;
-                }
                 str += sprintf(str, "PCR-%02d: ", i);
                 for (j = 0; j < TPM_DIGEST_SIZE; j++)
                         str += sprintf(str, "%02X ", *(data + 10 + j));
@@ -194,7 +229,7 @@ ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
                        char *buf)
 {
         u8 *data;
-        ssize_t len;
+        ssize_t err;
         int i, rc;
         char *str = buf;
 
@@ -208,14 +243,10 @@ ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
 
         memcpy(data, readpubek, sizeof(readpubek));
 
-        if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <
-            READ_PUBEK_RESULT_SIZE) {
-                dev_dbg(chip->dev, "A TPM error (%d) occurred "
-                                "attempting to read the PUBEK\n",
-                            be32_to_cpu(*((__be32 *) (data + 6))));
-                rc = 0;
+        err = transmit_cmd(chip, data, READ_PUBEK_RESULT_SIZE,
+                        "attempting to read the PUBEK");
+        if (err)
                 goto out;
-        }
 
         /* 
            ignore header 10 bytes
@@ -245,63 +276,59 @@ ssize_t tpm_show_pubek(struct device *dev, struct device_attribute *attr,
                 if ((i + 1) % 16 == 0)
                         str += sprintf(str, "\n");
         }
-        rc = str - buf;
 out:
+        rc = str - buf;
         kfree(data);
         return rc;
 }
 EXPORT_SYMBOL_GPL(tpm_show_pubek);
 
-#define CAP_VER_RESULT_SIZE 18
+#define CAP_VERSION_1_1 6
+#define CAP_VERSION_IDX 13
 static const u8 cap_version[] = {
         0, 193,                 /* TPM_TAG_RQU_COMMAND */
         0, 0, 0, 18,            /* length */
         0, 0, 0, 101,           /* TPM_ORD_GetCapability */
-        0, 0, 0, 6,
+        0, 0, 0, 0,
         0, 0, 0, 0
 };
 
-#define CAP_MANUFACTURER_RESULT_SIZE 18
-static const u8 cap_manufacturer[] = {
-        0, 193,                 /* TPM_TAG_RQU_COMMAND */
-        0, 0, 0, 22,            /* length */
-        0, 0, 0, 101,           /* TPM_ORD_GetCapability */
-        0, 0, 0, 5,
-        0, 0, 0, 4,
-        0, 0, 1, 3
-};
-
 ssize_t tpm_show_caps(struct device *dev, struct device_attribute *attr,
                       char *buf)
 {
-        u8 data[sizeof(cap_manufacturer)];
-        ssize_t len;
+        u8 data[30];
+        ssize_t rc;
         char *str = buf;
 
         struct tpm_chip *chip = dev_get_drvdata(dev);
         if (chip == NULL)
                 return -ENODEV;
 
-        memcpy(data, cap_manufacturer, sizeof(cap_manufacturer));
+        memcpy(data, tpm_cap, sizeof(tpm_cap));
+        data[TPM_CAP_IDX] = TPM_CAP_PROP;
+        data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_MANUFACTURER;
 
-        if ((len = tpm_transmit(chip, data, sizeof(data))) <
-            CAP_MANUFACTURER_RESULT_SIZE)
-                return len;
+        rc = transmit_cmd(chip, data, sizeof(data),
+                        "attempting to determine the manufacturer");
+        if (rc)
+                return 0;
 
         str += sprintf(str, "Manufacturer: 0x%x\n",
-                       be32_to_cpu(*((__be32 *) (data + 14))));
+                       be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_UINT32_1_IDX))));
 
         memcpy(data, cap_version, sizeof(cap_version));
+        data[CAP_VERSION_IDX] = CAP_VERSION_1_1;
+        rc = transmit_cmd(chip, data, sizeof(data),
+                        "attempting to determine the 1.1 version");
+        if (rc)
+                goto out;
 
-        if ((len = tpm_transmit(chip, data, sizeof(data))) <
-            CAP_VER_RESULT_SIZE)
-                return len;
-
-        str +=
-            sprintf(str, "TCG version: %d.%d\nFirmware version: %d.%d\n",
-                    (int) data[14], (int) data[15], (int) data[16],
-                    (int) data[17]);
+        str += sprintf(str,
+                       "TCG version: %d.%d\nFirmware version: %d.%d\n",
+                       (int) data[14], (int) data[15], (int) data[16],
+                       (int) data[17]);
 
+out:
         return str - buf;
 }
 EXPORT_SYMBOL_GPL(tpm_show_caps);