Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 22:21:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

tpm: ibmvtpm: Avoid error message when process gets signal while waiting

Browse Source 
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: 6674ff145e ("tpm_ibmvtpm: properly handle interrupted packet receptions")
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: George Wilson <gcwilson@linux.ibm.com>
Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
This commit is contained in:
Stefan Berger 2021-08-12 22:45:48 +03:00 committed by Jarkko Sakkinen
parent a4aed36ed5
commit 047d4226b0
2 changed files with 16 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/char/tpm/tpm_ibmvtpm.c
View File

@ -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) {
@ -237,7 +232,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
* 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;
ibmvtpm->tpm_processing_cmd = 1;
again:
rc = ibmvtpm_send_crq(ibmvtpm->vdev,
@ -255,7 +250,7 @@ again:
goto again;
}
dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc);
ibmvtpm->tpm_processing_cmd = false;
ibmvtpm->tpm_processing_cmd = 0;
}
spin_unlock(&ibmvtpm->rtce_lock);
@ -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 = 1,
.req_complete_val = 0,
.req_canceled = tpm_ibmvtpm_req_canceled,
};
@ -550,7 +547,7 @@ 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;
ibmvtpm->tpm_processing_cmd = 0;
wake_up_interruptible(&ibmvtpm->wq);
return;
default:
@ -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;

2
drivers/char/tpm/tpm_ibmvtpm.h
View File

@ -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