From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54728 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753170AbeFZRXo (ORCPT ); Tue, 26 Jun 2018 13:23:44 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5QHJThd063813 for ; Tue, 26 Jun 2018 13:23:44 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jusqwr7jc-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 26 Jun 2018 13:23:43 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 26 Jun 2018 11:23:43 -0600 From: Stefan Berger To: linux-integrity@vger.kernel.org, jarkko.sakkinen@linux.intel.com, zohar@linux.vnet.ibm.com Cc: jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Stefan Berger Subject: [PATCH v6 2/5] tpm: Implement tpm_default_chip() to find a TPM chip Date: Tue, 26 Jun 2018 13:23:28 -0400 In-Reply-To: <20180626172331.2505541-1-stefanb@linux.vnet.ibm.com> References: <20180626172331.2505541-1-stefanb@linux.vnet.ibm.com> Message-Id: <20180626172331.2505541-3-stefanb@linux.vnet.ibm.com> Sender: linux-integrity-owner@vger.kernel.org List-ID: Implement tpm_default_chip() to find the first TPM chip and return it to the caller while increasing the reference count on its device. This function can be used by other subsystems, such as IMA, to find the system's default TPM chip and use it for all subsequent TPM operations. Signed-off-by: Stefan Berger --- drivers/char/tpm/tpm-chip.c | 27 +++++++++++++++++++++++++++ include/linux/tpm.h | 5 +++++ 2 files changed, 32 insertions(+) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 242b716aed5e..f551061262c9 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -80,6 +80,33 @@ void tpm_put_ops(struct tpm_chip *chip) } EXPORT_SYMBOL_GPL(tpm_put_ops); +/** + * tpm_default_chip() - find a TPM chip and get a reference to it + */ +struct tpm_chip *tpm_default_chip(void) +{ + struct tpm_chip *chip, *res = NULL; + int chip_num = 0; + int chip_prev; + + mutex_lock(&idr_lock); + + do { + chip_prev = chip_num; + chip = idr_get_next(&dev_nums_idr, &chip_num); + if (chip) { + get_device(&chip->dev); + res = chip; + break; + } + } while (chip_prev != chip_num); + + mutex_unlock(&idr_lock); + + return res; +} +EXPORT_SYMBOL_GPL(tpm_default_chip); + /** * tpm_find_get_ops() - find and reserve a TPM chip * @chip: a &struct tpm_chip instance, %NULL for the default chip diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 06639fb6ab85..e0e51c49a0e6 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -61,6 +61,7 @@ extern int tpm_seal_trusted(struct tpm_chip *chip, extern int tpm_unseal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload, struct trusted_key_options *options); +extern struct tpm_chip *tpm_default_chip(void); #else static inline int tpm_is_tpm2(struct tpm_chip *chip) { @@ -96,5 +97,9 @@ static inline int tpm_unseal_trusted(struct tpm_chip *chip, { return -ENODEV; } +static inline struct tpm_chip *tpm_default_chip(void) +{ + return NULL; +} #endif #endif -- 2.17.1