From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752809AbeEGQHz (ORCPT ); Mon, 7 May 2018 12:07:55 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:43488 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752751AbeEGQHv (ORCPT ); Mon, 7 May 2018 12:07:51 -0400 From: Nayna Jain To: linux-integrity@vger.kernel.org Cc: zohar@linux.vnet.ibm.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, peterhuewe@gmx.de, jarkko.sakkinen@linux.intel.com, tpmdd@selhorst.net, jgunthorpe@obsidianresearch.com, patrickc@us.ibm.com, Nayna Jain Subject: [PATCH v3 1/2] tpm: reduce poll sleep time in tpm_transmit() Date: Mon, 7 May 2018 12:07:32 -0400 X-Mailer: git-send-email 2.13.3 In-Reply-To: <20180507160733.8817-1-nayna@linux.vnet.ibm.com> References: <20180507160733.8817-1-nayna@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18050716-0040-0000-0000-000004560696 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18050716-0041-0000-0000-000020FA4246 Message-Id: <20180507160733.8817-2-nayna@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-05-07_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805070162 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org tpm_try_transmit currently checks TPM status every 5 msecs between send and recv. It does so in a loop for the maximum timeout as defined in the TPM Interface Specification. However, the TPM may return before 5 msecs. Thus the polling interval for each iteration can be reduced, which improves overall performance. This patch changes the polling sleep time from 5 msecs to 1 msec. Additionally, this patch renames TPM_POLL_SLEEP to TPM_TIMEOUT_POLL and moves it to tpm.h as an enum value. After this change, performance on a system[1] with a TPM 1.2 with an 8 byte burstcount for 1000 extends improved from ~14 sec to ~10.7 sec. [1] All tests are performed on an x86 based, locked down, single purpose closed system. It has Infineon TPM 1.2 using LPC Bus. Signed-off-by: Nayna Jain --- drivers/char/tpm/tpm-interface.c | 2 +- drivers/char/tpm/tpm.h | 3 ++- drivers/char/tpm/tpm_tis_core.c | 10 ++-------- 3 files changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 6201aab374e6..e32f6e85dc6d 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -489,7 +489,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, goto out; } - tpm_msleep(TPM_TIMEOUT); + tpm_msleep(TPM_TIMEOUT_POLL); rmb(); } while (time_before(jiffies, stop)); diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index eedcd9cf30bc..ca05828b6981 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -53,7 +53,8 @@ enum tpm_const { enum tpm_timeout { TPM_TIMEOUT = 5, /* msecs */ TPM_TIMEOUT_RETRY = 100, /* msecs */ - TPM_TIMEOUT_RANGE_US = 300 /* usecs */ + TPM_TIMEOUT_RANGE_US = 300, /* usecs */ + TPM_TIMEOUT_POLL = 1 /* msecs */ }; /* TPM addresses */ diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 5a1f47b43947..493401f5fd39 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -31,12 +31,6 @@ #include "tpm.h" #include "tpm_tis_core.h" -/* This is a polling delay to check for status and burstcount. - * As per ddwg input, expectation is that status check and burstcount - * check should return within few usecs. - */ -#define TPM_POLL_SLEEP 1 /* msec */ - static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value); static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, @@ -90,7 +84,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, } } else { do { - tpm_msleep(TPM_POLL_SLEEP); + tpm_msleep(TPM_TIMEOUT_POLL); status = chip->ops->status(chip); if ((status & mask) == mask) return 0; @@ -234,7 +228,7 @@ static int get_burstcount(struct tpm_chip *chip) burstcnt = (value >> 8) & 0xFFFF; if (burstcnt) return burstcnt; - tpm_msleep(TPM_POLL_SLEEP); + tpm_msleep(TPM_TIMEOUT_POLL); } while (time_before(jiffies, stop)); return -EBUSY; } -- 2.13.3 From mboxrd@z Thu Jan 1 00:00:00 1970 From: nayna@linux.vnet.ibm.com (Nayna Jain) Date: Mon, 7 May 2018 12:07:32 -0400 Subject: [PATCH v3 1/2] tpm: reduce poll sleep time in tpm_transmit() In-Reply-To: <20180507160733.8817-1-nayna@linux.vnet.ibm.com> References: <20180507160733.8817-1-nayna@linux.vnet.ibm.com> Message-ID: <20180507160733.8817-2-nayna@linux.vnet.ibm.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org tpm_try_transmit currently checks TPM status every 5 msecs between send and recv. It does so in a loop for the maximum timeout as defined in the TPM Interface Specification. However, the TPM may return before 5 msecs. Thus the polling interval for each iteration can be reduced, which improves overall performance. This patch changes the polling sleep time from 5 msecs to 1 msec. Additionally, this patch renames TPM_POLL_SLEEP to TPM_TIMEOUT_POLL and moves it to tpm.h as an enum value. After this change, performance on a system[1] with a TPM 1.2 with an 8 byte burstcount for 1000 extends improved from ~14 sec to ~10.7 sec. [1] All tests are performed on an x86 based, locked down, single purpose closed system. It has Infineon TPM 1.2 using LPC Bus. Signed-off-by: Nayna Jain --- drivers/char/tpm/tpm-interface.c | 2 +- drivers/char/tpm/tpm.h | 3 ++- drivers/char/tpm/tpm_tis_core.c | 10 ++-------- 3 files changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 6201aab374e6..e32f6e85dc6d 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -489,7 +489,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, goto out; } - tpm_msleep(TPM_TIMEOUT); + tpm_msleep(TPM_TIMEOUT_POLL); rmb(); } while (time_before(jiffies, stop)); diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index eedcd9cf30bc..ca05828b6981 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -53,7 +53,8 @@ enum tpm_const { enum tpm_timeout { TPM_TIMEOUT = 5, /* msecs */ TPM_TIMEOUT_RETRY = 100, /* msecs */ - TPM_TIMEOUT_RANGE_US = 300 /* usecs */ + TPM_TIMEOUT_RANGE_US = 300, /* usecs */ + TPM_TIMEOUT_POLL = 1 /* msecs */ }; /* TPM addresses */ diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 5a1f47b43947..493401f5fd39 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -31,12 +31,6 @@ #include "tpm.h" #include "tpm_tis_core.h" -/* This is a polling delay to check for status and burstcount. - * As per ddwg input, expectation is that status check and burstcount - * check should return within few usecs. - */ -#define TPM_POLL_SLEEP 1 /* msec */ - static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value); static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, @@ -90,7 +84,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, } } else { do { - tpm_msleep(TPM_POLL_SLEEP); + tpm_msleep(TPM_TIMEOUT_POLL); status = chip->ops->status(chip); if ((status & mask) == mask) return 0; @@ -234,7 +228,7 @@ static int get_burstcount(struct tpm_chip *chip) burstcnt = (value >> 8) & 0xFFFF; if (burstcnt) return burstcnt; - tpm_msleep(TPM_POLL_SLEEP); + tpm_msleep(TPM_TIMEOUT_POLL); } while (time_before(jiffies, stop)); return -EBUSY; } -- 2.13.3 -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html