From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCA18C433EF for ; Thu, 30 Jun 2022 23:29:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231316AbiF3X3z (ORCPT ); Thu, 30 Jun 2022 19:29:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229531AbiF3X3v (ORCPT ); Thu, 30 Jun 2022 19:29:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4D5F44A26; Thu, 30 Jun 2022 16:29:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6EA1861976; Thu, 30 Jun 2022 23:29:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EA59C341C8; Thu, 30 Jun 2022 23:29:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656631787; bh=8zDDjljtuKH3a9AgBRxpKjei6gBVIIFR7+gDI3NefmA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kE8+B/IVSYN+lmjrK1jVUxKOa2NnjWCmwEJsjs3jP1IMl1x7l5mLHXw91DcBfAf6q VlmkHnXdnwJr4bIzhgv/+z1Nc3+8t7tFx/NlVbsxCNKX7/mG+EgvNIkYav0KOu07Fe MIuQ32T0/zSjbSHKA5Ja1LvcD6i6hiUDA8h74llQhdq0TZffxelSqpV2ZqKu8NEeaY YWmHJNU2kKd/QcxLpGU4GWSR0XACUbdqx5XAwDJCkrNcMD14lYc2BPSlMzvZt27Pat Wwa9y3xj0SpKbZEhqkxVMgh3k1ZDiIXjeKKX2d4OX/X+UMqs9vwS1teSpII6PRdnuv HKdJfDn0wIM9g== Date: Fri, 1 Jul 2022 02:29:44 +0300 From: Jarkko Sakkinen To: Lino Sanfilippo Cc: peterhuewe@gmx.de, jgg@ziepe.ca, stefanb@linux.vnet.ibm.com, linux@mniewoehner.de, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, l.sanfilippo@kunbus.com, lukas@wunner.de, p.rosenberger@kunbus.com Subject: Re: [PATCH v7 07/10] tmp, tmp_tis: Implement usage counter for locality Message-ID: References: <20220629232653.1306735-1-LinoSanfilippo@gmx.de> <20220629232653.1306735-8-LinoSanfilippo@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220629232653.1306735-8-LinoSanfilippo@gmx.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 30, 2022 at 01:26:50AM +0200, Lino Sanfilippo wrote: > From: Lino Sanfilippo > > Implement a usage counter for the (default) locality used by the TPM TIS > driver: > Request the locality from the TPM if it has not been claimed yet, otherwise > only increment the counter. Also release the locality if the counter is 0 > otherwise only decrement the counter. Ensure thread-safety by protecting > the counter with a mutex. > > This allows to request and release the locality from a thread and the > interrupt handler at the same time without the danger to interfere with > each other. > > By doing this refactor the names of the amended functions to use the proper > prefix. > > Signed-off-by: Lino Sanfilippo > Tested-by: Michael Niew??hner > --- > drivers/char/tpm/tpm_tis_core.c | 75 ++++++++++++++++++++++----------- > drivers/char/tpm/tpm_tis_core.h | 2 + > 2 files changed, 53 insertions(+), 24 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index bd4eeb0b2192..e50a2c78de9f 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -165,16 +165,27 @@ static bool check_locality(struct tpm_chip *chip, int l) > return false; > } > > -static int release_locality(struct tpm_chip *chip, int l) > +static int tpm_tis_release_locality_locked(struct tpm_tis_data *priv, int l) > +{ > + tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY); > + > + return 0; > +} > + > +static int tpm_tis_release_locality(struct tpm_chip *chip, int l) > { > struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > > - tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY); > + mutex_lock(&priv->locality_count_mutex); > + priv->locality_count--; > + if (priv->locality_count == 0) > + tpm_tis_release_locality_locked(priv, l); > + mutex_unlock(&priv->locality_count_mutex); > > return 0; > } > > -static int request_locality(struct tpm_chip *chip, int l) > +static int tpm_tis_request_locality_locked(struct tpm_chip *chip, int l) > { > struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > unsigned long stop, timeout; > @@ -215,6 +226,20 @@ static int request_locality(struct tpm_chip *chip, int l) > return -1; > } > > +static int tpm_tis_request_locality(struct tpm_chip *chip, int l) > +{ > + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > + int ret = 0; > + > + mutex_lock(&priv->locality_count_mutex); > + if (priv->locality_count == 0) > + ret = tpm_tis_request_locality_locked(chip, l); > + if (!ret) > + priv->locality_count++; > + mutex_unlock(&priv->locality_count_mutex); > + return ret; > +} > + > static u8 tpm_tis_status(struct tpm_chip *chip) > { > struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > @@ -668,7 +693,7 @@ static int probe_itpm(struct tpm_chip *chip) > if (vendor != TPM_VID_INTEL) > return 0; > > - if (request_locality(chip, 0) != 0) > + if (tpm_tis_request_locality(chip, 0) != 0) > return -EBUSY; > > rc = tpm_tis_send_data(chip, cmd_getticks, len); > @@ -689,7 +714,7 @@ static int probe_itpm(struct tpm_chip *chip) > > out: > tpm_tis_ready(chip); > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > > return rc; > } > @@ -751,7 +776,7 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip) > cap_t cap; > int ret; > > - ret = request_locality(chip, 0); > + ret = tpm_tis_request_locality(chip, 0); > if (ret < 0) > return ret; > > @@ -760,7 +785,7 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip) > else > ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc, 0); > > - release_locality(chip, 0); > + tpm_tis_release_locality(chip, 0); > > return ret; > } > @@ -785,33 +810,33 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask, > } > priv->irq = irq; > > - rc = request_locality(chip, 0); > + rc = tpm_tis_request_locality(chip, 0); > if (rc < 0) > return rc; > > rc = tpm_tis_read8(priv, TPM_INT_VECTOR(priv->locality), > &original_int_vec); > if (rc < 0) { > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > return rc; > } > > rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), irq); > if (rc < 0) { > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > return rc; > } > > rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &int_status); > if (rc < 0) { > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > return rc; > } > > /* Clear all existing */ > rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), int_status); > if (rc < 0) { > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > return rc; > } > > @@ -819,11 +844,11 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask, > rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), > intmask | TPM_GLOBAL_INT_ENABLE); > if (rc < 0) { > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > return rc; > } > > - release_locality(chip, priv->locality); > + tpm_tis_release_locality(chip, priv->locality); > clear_bit(TPM_TIS_IRQ_TESTED, &priv->flags); > > /* Generate an interrupt by having the core call through to > @@ -959,8 +984,8 @@ static const struct tpm_class_ops tpm_tis = { > .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID, > .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID, > .req_canceled = tpm_tis_req_canceled, > - .request_locality = request_locality, > - .relinquish_locality = release_locality, > + .request_locality = tpm_tis_request_locality, > + .relinquish_locality = tpm_tis_release_locality, > .clk_enable = tpm_tis_clkrun_enable, > }; > > @@ -994,6 +1019,8 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > priv->timeout_min = TPM_TIMEOUT_USECS_MIN; > priv->timeout_max = TPM_TIMEOUT_USECS_MAX; > priv->phy_ops = phy_ops; > + priv->locality_count = 0; > + mutex_init(&priv->locality_count_mutex); > > dev_set_drvdata(&chip->dev, priv); > > @@ -1071,14 +1098,14 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > > intmask &= ~TPM_GLOBAL_INT_ENABLE; > > - rc = request_locality(chip, 0); > + rc = tpm_tis_request_locality(chip, 0); > if (rc < 0) { > rc = -ENODEV; > goto out_err; > } > > tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask); > - release_locality(chip, 0); > + tpm_tis_release_locality(chip, 0); > > rc = tpm_chip_start(chip); > if (rc) > @@ -1112,13 +1139,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > * proper timeouts for the driver. > */ > > - rc = request_locality(chip, 0); > + rc = tpm_tis_request_locality(chip, 0); > if (rc < 0) > goto out_err; > > rc = tpm_get_timeouts(chip); > > - release_locality(chip, 0); > + tpm_tis_release_locality(chip, 0); > > if (rc) { > dev_err(dev, "Could not get TPM timeouts and durations\n"); > @@ -1138,11 +1165,11 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > dev_err(&chip->dev, FW_BUG > "TPM interrupt not working, polling instead\n"); > > - rc = request_locality(chip, 0); > + rc = tpm_tis_request_locality(chip, 0); > if (rc < 0) > goto out_err; > disable_interrupts(chip); > - release_locality(chip, 0); > + tpm_tis_release_locality(chip, 0); > } > } > > @@ -1209,13 +1236,13 @@ int tpm_tis_resume(struct device *dev) > * an error code but for unknown reason it isn't handled. > */ > if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { > - ret = request_locality(chip, 0); > + ret = tpm_tis_request_locality(chip, 0); > if (ret < 0) > return ret; > > tpm1_do_selftest(chip); > > - release_locality(chip, 0); > + tpm_tis_release_locality(chip, 0); > } > > return 0; > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index e005eb99480e..7c6c14707e31 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -91,6 +91,8 @@ enum tpm_tis_flags { > > struct tpm_tis_data { > u16 manufacturer_id; > + struct mutex locality_count_mutex; > + unsigned int locality_count; > int locality; > int irq; > unsigned int int_mask; > -- > 2.25.1 > I'm kind of thinking that should tpm_tis_data have a lock for its contents? I kind of doubt that we would ever need more than one lock for it, and it would give some more ensurance to not be race, especially when re-enabling interrupts this feels important to be "extra safe". I looked at this commit, and did not see anything that would prevent using a spin lock instead of mutex. With a spin lock priv can be accessed also in the interrupt context. So instead prepend this patch with a patch that adds: struct spin_lock lock; And something like: static inline struct tpm_tis_data *tpm_tis_priv_get(struct tpm_chip *chip) { struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); spin_lock(&priv->lock); return priv; } static inline void tpm_tis_priv_put(struct tpm_tis_data *priv) { spin_unlock(&priv->lock); } And change the sites where priv is used to acquire the instance with this. BR, Jarkko