From 6674ff145eef1f158e3d1d065cb1e19f315d909b Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Wed, 9 Dec 2015 08:52:01 -0500 Subject: 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 Tested-by: Hon Ching(Vicky) Lo Reviewed-by: Jarkko Sakkinen Reviewed-by: Ashley Lai Signed-off-by: Jarkko Sakkinen Acked-by: Peter Huewe --- drivers/char/tpm/tpm_ibmvtpm.c | 22 ++++++++++++++++++++-- drivers/char/tpm/tpm_ibmvtpm.h | 1 + 2 files changed, 21 insertions(+), 2 deletions(-) (limited to 'drivers/char') 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 -- cgit v1.2.3