[PATCH v2 4/5] tpm: migrate tpm2_get_tpm_pt() to use struct tpm_buf

[Jarkko Sakkinen]

In order to make struct tpm_buf the first class object for constructing TPM
commands, migrate tpm2_get_tpm_pt() to use it.

Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
---
 drivers/char/tpm/tpm2-cmd.c | 63 +++++++++++++++++----------------------------
 1 file changed, 23 insertions(+), 40 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 890d83c5c78b..e02f7d46e9ac 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -27,20 +27,6 @@ enum tpm2_session_attributes {
        TPM2_SA_CONTINUE_SESSION        = BIT(0),
 };
 
-struct tpm2_get_tpm_pt_in {
-       __be32  cap_id;
-       __be32  property_id;
-       __be32  property_cnt;
-} __packed;
-
-struct tpm2_get_tpm_pt_out {
-       u8      more_data;
-       __be32  subcap_id;
-       __be32  property_cnt;
-       __be32  property_id;
-       __be32  value;
-} __packed;
-
 struct tpm2_get_random_in {
        __be16  size;
 } __packed;
@@ -51,8 +37,6 @@ struct tpm2_get_random_out {
 } __packed;
 
 union tpm2_cmd_params {
-       struct  tpm2_get_tpm_pt_in      get_tpm_pt_in;
-       struct  tpm2_get_tpm_pt_out     get_tpm_pt_out;
        struct  tpm2_get_random_in      getrandom_in;
        struct  tpm2_get_random_out     getrandom_out;
 };
@@ -377,19 +361,6 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t 
max)
        return total ? total : -EIO;
 }
 
-#define TPM2_GET_TPM_PT_IN_SIZE \
-       (sizeof(struct tpm_input_header) + \
-        sizeof(struct tpm2_get_tpm_pt_in))
-
-#define TPM2_GET_TPM_PT_OUT_BODY_SIZE \
-        sizeof(struct tpm2_get_tpm_pt_out)
-
-static const struct tpm_input_header tpm2_get_tpm_pt_header = {
-       .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
-       .length = cpu_to_be32(TPM2_GET_TPM_PT_IN_SIZE),
-       .ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
-};
-
 /**
  * tpm2_flush_context_cmd() - execute a TPM2_FlushContext command
  * @chip: TPM chip to use
@@ -723,6 +694,14 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
        return rc;
 }
 
+struct tpm2_get_cap_out {
+       u8 more_data;
+       __be32 subcap_id;
+       __be32 property_cnt;
+       __be32 property_id;
+       __be32 value;
+} __packed;
+
 /**
  * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
  * @chip:              TPM chip to use.
@@ -735,19 +714,23 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
 ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
                        const char *desc)
 {
-       struct tpm2_cmd cmd;
+       struct tpm2_get_cap_out *out;
+       struct tpm_buf buf;
        int rc;
 
-       cmd.header.in = tpm2_get_tpm_pt_header;
-       cmd.params.get_tpm_pt_in.cap_id = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
-       cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(property_id);
-       cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
-
-       rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
-                             TPM2_GET_TPM_PT_OUT_BODY_SIZE, 0, desc);
-       if (!rc)
-               *value = be32_to_cpu(cmd.params.get_tpm_pt_out.value);
-
+       rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+       if (rc)
+               return rc;
+       tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
+       tpm_buf_append_u32(&buf, property_id);
+       tpm_buf_append_u32(&buf, 1);
+       rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0, NULL);
+       if (!rc) {
+               out = (struct tpm2_get_cap_out *)
+                       &buf.data[TPM_HEADER_SIZE];
+               *value = be32_to_cpu(out->value);
+       }
+       tpm_buf_destroy(&buf);
        return rc;
 }
 EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
-- 
2.15.1