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authorStefan Berger <stefanb@linux.vnet.ibm.com>2015-12-09 08:52:01 -0500
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2015-12-20 15:27:12 +0200
commit6674ff145eef1f158e3d1d065cb1e19f315d909b (patch)
tree82eb29e89966d0638edb5edbd0991a7ff5a2320e /drivers/char
parentb8ba1e744445d65dad7dd61db909e7f2b89df35e (diff)
downloadlinux-6674ff145eef1f158e3d1d065cb1e19f315d909b.tar.bz2
tpm_ibmvtpm: properly handle interrupted packet receptions
When the TPM response reception is interrupted in the wait_event_interruptable call, the TPM is still busy processing the command and will only deliver the response later. So we have to wait for an outstanding response before sending a new request to avoid trying to put a 2nd request into the CRQ. Also reset the res_len before sending a command so we will end up in that wait_event_interruptable() waiting for the response rather than reading the command packet as a response. The easiest way to trigger the problem is to run the following cd /sys/device/vio/71000004 while :; cat pcrs >/dev/null; done And press Ctrl-C. This will then display an error tpm_ibmvtpm 71000004: tpm_transmit: tpm_recv: error -4 followed by several other errors once interaction with the TPM resumes. tpm_ibmvtpm 71000004: A TPM error (101) occurred attempting to determine the number of PCRS. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> Tested-by: Hon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Reviewed-by: Ashley Lai <ashley@ashleylai.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Acked-by: Peter Huewe <peterhuewe@gmx.de>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tpm/tpm_ibmvtpm.c22
-rw-r--r--drivers/char/tpm/tpm_ibmvtpm.h1
2 files changed, 21 insertions, 2 deletions
diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 3e6a22658b63..b0a9a9e34241 100644
--- 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:
diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h
index 6af92890518f..91dfe766d080 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.h
+++ b/drivers/char/tpm/tpm_ibmvtpm.h
@@ -45,6 +45,7 @@ struct ibmvtpm_dev {
wait_queue_head_t wq;
u16 res_len;
u32 vtpm_version;
+ bool tpm_processing_cmd;
};
#define CRQ_RES_BUF_SIZE PAGE_SIZE