CHERRY-PICK: Fix autotest support for a new TPM class directory.

Kernel TPM patches from 4.x moved /sys/class/misc/tpm0 to /sys/class/tpm/tpm0.
The last attempt to support both paths in firmware_TPMExtend failed to
differentiate between host and device operation.  Rather than add a second
device operation to check the path, simply use the wildcard to find the
right file.
This assumes (safely, I think) that the system has only one tpm0.

TEST=Confirm firmware_TPMExtend gives valid "Dumping PCRs read from device"
     data in both 3.18 and 3.14 kernels.

Original Change-Id: I06626370c8ae90fd8fb754a9b2a6bd895e46ad62
Original Reviewed-on:
Original Commit-Ready: Bryan Freed <>
Original Tested-by: Bryan Freed <>
Original Reviewed-by: Julius Werner <>

Change-Id: Id6571af86335d3e2603301ad12451540ed4b17d5
Signed-off-by: <>
Reviewed-by: Bernie Thompson <>
Commit-Queue: Bernie Thompson <>
diff --git a/server/site_tests/firmware_TPMExtend/ b/server/site_tests/firmware_TPMExtend/
index 44b355f..842a679 100644
--- a/server/site_tests/firmware_TPMExtend/
+++ b/server/site_tests/firmware_TPMExtend/
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
-import hashlib, logging, os
+import hashlib, logging
 from autotest_lib.client.common_lib import error
 from autotest_lib.server.cros.faft.firmware_test import FirmwareTest
@@ -19,9 +19,7 @@
     def _check_pcr(self, num, hash_obj):
         """Returns true iff PCR |num| was extended with hashlib |hash_obj|."""
-        pcrs_file='/sys/class/misc/tpm0/device/pcrs'
-        if not os.path.exists(pcrs_file):
-            pcrs_file='/sys/class/tpm/tpm0/device/pcrs'
+        pcrs_file='/sys/class/*/tpm0/device/pcrs'
         pcrs = '\n'.join(self.faft_client.system.run_shell_command_get_output(
                         'cat %s' % pcrs_file))
         logging.debug('Dumping PCRs read from device: \n%s', pcrs)