linux-kernel - [PATCH v9 2/5] tpm: Add optional logging of TPM command durations

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 13 Jul 2016 09:19:33 -0700
From:	Ed Swierk <eswierk@...portsystems.com>
To:	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org
Cc:	jarkko.sakkinen@...ux.intel.com, jgunthorpe@...idianresearch.com,
	stefanb@...ibm.com, eswierk@...portsystems.com
Subject: [PATCH v9 2/5] tpm: Add optional logging of TPM command durations

Some TPMs violate their own advertised command durations. This is much
easier to debug with data about how long each command actually takes
to complete. Add debug messages that can be enabled by running

  echo -n 'module tpm +p' >/sys/kernel/debug/dynamic_debug/control

on a kernel configured with DYNAMIC_DEBUG=y.

Signed-off-by: Ed Swierk <eswierk@...portsystems.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
 drivers/char/tpm/tpm-interface.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5e3c1b6..a4beb53 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -335,13 +335,14 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
 {
 	ssize_t rc;
 	u32 count, ordinal;
-	unsigned long stop;
+	unsigned long start, stop;
 
 	if (bufsiz > TPM_BUFSIZE)
 		bufsiz = TPM_BUFSIZE;
 
 	count = be32_to_cpu(*((__be32 *) (buf + 2)));
 	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
+	dev_dbg(&chip->dev, "starting command %d count %d\n", ordinal, count);
 	if (count == 0)
 		return -ENODATA;
 	if (count > bufsiz) {
@@ -362,18 +363,23 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
 	if (chip->flags & TPM_CHIP_FLAG_IRQ)
 		goto out_recv;
 
+	start = jiffies;
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		stop = jiffies + tpm2_calc_ordinal_duration(chip, ordinal);
+		stop = start + tpm2_calc_ordinal_duration(chip, ordinal);
 	else
-		stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);
+		stop = start + tpm_calc_ordinal_duration(chip, ordinal);
 	do {
 		u8 status = chip->ops->status(chip);
 		if ((status & chip->ops->req_complete_mask) ==
-		    chip->ops->req_complete_val)
+		    chip->ops->req_complete_val) {
+			dev_dbg(&chip->dev, "completed command %d in %d ms\n",
+				ordinal, jiffies_to_msecs(jiffies - start));
 			goto out_recv;
+		}
 
 		if (chip->ops->req_canceled(chip, status)) {
-			dev_err(&chip->dev, "Operation Canceled\n");
+			dev_err(&chip->dev, "canceled command %d after %d ms\n",
+				ordinal, jiffies_to_msecs(jiffies - start));
 			rc = -ECANCELED;
 			goto out;
 		}
@@ -383,7 +389,8 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
 	} while (time_before(jiffies, stop));
 
 	chip->ops->cancel(chip);
-	dev_err(&chip->dev, "Operation Timed out\n");
+	dev_err(&chip->dev, "command %d timed out after %d ms\n", ordinal,
+		jiffies_to_msecs(jiffies - start));
 	rc = -ETIME;
 	goto out;
 
-- 
1.9.1