tpm_ibmvtpm: properly handle interrupted packet receptions

[cascardo/linux.git] / drivers / char / tpm / tpm_ibmvtpm.c

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 3e6a226..b0a9a9e 100644 (file)
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -90,7 +90,7 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
                return 0;
        }
 
-       sig = wait_event_interruptible(ibmvtpm->wq, ibmvtpm->res_len != 0);
+       sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);
        if (sig)
                return -EINTR;
 
@@ -125,7 +125,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
        struct ibmvtpm_dev *ibmvtpm;
        struct ibmvtpm_crq crq;
        __be64 *word = (__be64 *)&crq;
-       int rc;
+       int rc, sig;
 
        ibmvtpm = (struct ibmvtpm_dev *)TPM_VPRIV(chip);
 
@@ -141,18 +141,35 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
                return -EIO;
        }
 
+       if (ibmvtpm->tpm_processing_cmd) {
+               dev_info(ibmvtpm->dev,
+                        "Need to wait for TPM to finish\n");
+               /* wait for previous command to finish */
+               sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);
+               if (sig)
+                       return -EINTR;
+       }
+
        spin_lock(&ibmvtpm->rtce_lock);
+       ibmvtpm->res_len = 0;
        memcpy((void *)ibmvtpm->rtce_buf, (void *)buf, count);
        crq.valid = (u8)IBMVTPM_VALID_CMD;
        crq.msg = (u8)VTPM_TPM_COMMAND;
        crq.len = cpu_to_be16(count);
        crq.data = cpu_to_be32(ibmvtpm->rtce_dma_handle);
 
+       /*
+        * set the processing flag before the Hcall, since we may get the
+        * result (interrupt) before even being able to check rc.
+        */
+       ibmvtpm->tpm_processing_cmd = true;
+
        rc = ibmvtpm_send_crq(ibmvtpm->vdev, be64_to_cpu(word[0]),
                              be64_to_cpu(word[1]));
        if (rc != H_SUCCESS) {
                dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc);
                rc = 0;
+               ibmvtpm->tpm_processing_cmd = false;
        } else
                rc = count;
 
@@ -515,6 +532,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq,
                case VTPM_TPM_COMMAND_RES:
                        /* len of the data in rtce buffer */
                        ibmvtpm->res_len = be16_to_cpu(crq->len);
+                       ibmvtpm->tpm_processing_cmd = false;
                        wake_up_interruptible(&ibmvtpm->wq);
                        return;
                default: