[PATCH v4 1/2] tpm: ibmvtpm: Avoid error message when process gets signal while waiting
From: Stefan Berger <hidden>
Date: 2021-08-09 19:22:27
Also in:
linux-integrity, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest, tpm device driver · Maintainers:
Madhavan Srinivasan, Linus Torvalds, Peter Huewe, Jarkko Sakkinen
From: Stefan Berger <stefanb@linux.ibm.com> When rngd is run as root then lots of these types of message will appear in the kernel log if the TPM has been configured to provide random bytes: [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4 The issue is caused by the following call that is interrupted while waiting for the TPM's response. sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); Rather than waiting for the response in the low level driver, have it use the polling loop in tpm_try_transmit() that uses a command's duration to poll until a result has been returned by the TPM, thus ending when the timeout has occurred but not responding to signals and ctrl-c anymore. To stay in this polling loop extend tpm_ibmvtpm_status() to return 'true' for as long as the vTPM is indicated as being busy in tpm_processing_cmd. Since the loop requires the TPM's timeouts, get them now using tpm_get_timeouts() after setting the TPM2 version flag on the chip. To recreat the resolved issue start rngd like this: sudo rngd -r /dev/hwrng -t sudo rngd -r /dev/tpm0 -t Link: https://bugzilla.redhat.com/show_bug.cgi?id=1981473 Fixes: 6674ff145eef ("tpm_ibmvtpm: properly handle interrupted packet receptions") Cc: Nayna Jain <nayna@linux.ibm.com> Cc: George Wilson <redacted> Reported-by: Nageswara R Sastry <redacted> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> --- drivers/char/tpm/tpm_ibmvtpm.c | 20 ++++++++++++-------- drivers/char/tpm/tpm_ibmvtpm.h | 2 +- 2 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 903604769de9..7a9eca5768f8 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c@@ -106,17 +106,12 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count) { struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); u16 len; - int sig; if (!ibmvtpm->rtce_buf) { dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n"); return 0; } - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); - if (sig) - return -EINTR; - len = ibmvtpm->res_len; if (count < len) {
@@ -269,7 +264,9 @@ static void tpm_ibmvtpm_cancel(struct tpm_chip *chip) static u8 tpm_ibmvtpm_status(struct tpm_chip *chip) { - return 0; + struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); + + return ibmvtpm->tpm_processing_cmd; } /**
@@ -457,7 +454,7 @@ static const struct tpm_class_ops tpm_ibmvtpm = { .send = tpm_ibmvtpm_send, .cancel = tpm_ibmvtpm_cancel, .status = tpm_ibmvtpm_status, - .req_complete_mask = 0, + .req_complete_mask = true, .req_complete_val = 0, .req_canceled = tpm_ibmvtpm_req_canceled, };
@@ -688,8 +685,15 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev, goto init_irq_cleanup; } - if (!strcmp(id->compat, "IBM,vtpm20")) { + + if (!strcmp(id->compat, "IBM,vtpm20")) chip->flags |= TPM_CHIP_FLAG_TPM2; + + rc = tpm_get_timeouts(chip); + if (rc) + goto init_irq_cleanup; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { rc = tpm2_get_cc_attrs_tbl(chip); if (rc) goto init_irq_cleanup;
diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h
index b92aa7d3e93e..51198b137461 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.h
+++ b/drivers/char/tpm/tpm_ibmvtpm.h@@ -41,7 +41,7 @@ struct ibmvtpm_dev { wait_queue_head_t wq; u16 res_len; u32 vtpm_version; - bool tpm_processing_cmd; + u8 tpm_processing_cmd; }; #define CRQ_RES_BUF_SIZE PAGE_SIZE
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2.31.1