From patchwork Wed Jun 9 06:09:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Wiklander X-Patchwork-Id: 12309025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18C83C47095 for ; Wed, 9 Jun 2021 06:11:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DB177610A5 for ; Wed, 9 Jun 2021 06:11:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB177610A5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+9svEeV73ulULO1cMKAq3KZqckAUwmNzv/Mv8N4gNrs=; b=m0l6XyD64W3HJT z+gLvWj7/E5zqgg9Kr2WX75Dy/kOTe4NrCNz1Yds6C53wT57YKXgL2llS4slhub9hdxPF4cyFaNKF yg+HqToNA/lrOdHPdZ3NmcpDAmV8BjCHH7za7+ebPmTVRShT2F2zmETIRAXMzE2K4kK5+PHpqxwal QW40tZkBsIRmXWDGf9tgy2r9DYnH0is0eKt8G5Mq/tJH+SS+tIJSVydZquYUHwOjDP1EcI3bGIWl9 lqWM2yMtwGhGix4OCs3wh0zdkEJH5GgFs+NfY+xPKejxIbOfskIOMGRxgE3EkNSw8HE6j9Yd2vFon kPUIAgF+vXvks8vlfWPA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqrPD-00BrXM-53; Wed, 09 Jun 2021 06:09:35 +0000 Received: from mail-lj1-x235.google.com ([2a00:1450:4864:20::235]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqrP0-00BrUx-8Q for linux-arm-kernel@lists.infradead.org; Wed, 09 Jun 2021 06:09:23 +0000 Received: by mail-lj1-x235.google.com with SMTP id r14so11008485ljd.10 for ; Tue, 08 Jun 2021 23:09:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=nE0O5cQU8hO3PBDLKhrY8XOB0KUsBuVPprzerF6bl2k=; b=J74fga/z7TlVhMK6Na5wwQmghWcMwhzIFoe+ZCd9kG9iCmWkcDx82EslEpikoqGc0t ICi+C7P0wei4NTr1oQnNYuR3qEGuK02ma+fambTC1nueLMZBlNIch5VLAlXTf61LcoI2 9LMWmrfq8zeBirMsJIGXIDscwNSr3Ecs9o8NlBLziOhByGwvfS/8VKhx2VJ5awTB/e5A YBnlExfAAxINrnBbRtr6Xp3cMIKHD+KweY2nQ9mwep5acZXhbHOGiB+rkIqxXg3j7B40 GltJKR1OzSgBA0XIJsc+5360S5W0ZTW2Ew++nDg9cgCL+Z9z9MBsUi2No+fQK9ElD/ki A97g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=nE0O5cQU8hO3PBDLKhrY8XOB0KUsBuVPprzerF6bl2k=; b=N55JP60/MyBZAxvLQncBBp90OegB9VMbqkl/FOWDWSWHqTatf9Lo0t0YR2vPUrlKgX 6OazB7BGhGsIyKG9goLWfXJM7yGtE1z1+e5tCyd04XOTgmxnTgbkUGz+evMkweEtxz0d Lw1ZDdlTPAmUQ/8HtkwdmOFeIWno7IP0Byi9+iwVjyR72v7uH5F13GJfybA89Z4ywc/m TZbIErn+3/pn3BEOZknpFAavL7yxjNblPpLBcdMrr97LEpKB1LeoEkAfYgtCw47+WcST 0OBrakJVj7l315/FO5hrop0ti2HgouK1SvTC47LMa+WvLILp6UikCTMqou5lcefvIqoA At9A== X-Gm-Message-State: AOAM530Khr2o3+DUovpl5uT+xlcrAgCfalwgd0WB/RZDugk8GLnKPjhx sRVXIONILE/4S3Y7D3fZRkFM2j+DuU3fvw== X-Google-Smtp-Source: ABdhPJyvd6YO+nxaZONxLcnWYv/Dvs+Q46kPYvQyG9wnXM2O2vFU8cNnt+LDOdiEB77NEseVcecR4A== X-Received: by 2002:a2e:9cd:: with SMTP id 196mr20309790ljj.457.1623218959561; Tue, 08 Jun 2021 23:09:19 -0700 (PDT) Received: from jade.urgonet (h-79-136-85-3.A175.priv.bahnhof.se. [79.136.85.3]) by smtp.gmail.com with ESMTPSA id l26sm213735ljg.87.2021.06.08.23.09.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Jun 2021 23:09:19 -0700 (PDT) From: Jens Wiklander To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, op-tee@lists.trustedfirmware.org Cc: Jerome Forissier , Etienne Carriere , Sumit Garg , Vincent Guittot , Jens Wiklander Subject: [PATCH 2/4] tee: add tee_dev_open_helper() primitive Date: Wed, 9 Jun 2021 08:09:08 +0200 Message-Id: <20210609060910.1500481-3-jens.wiklander@linaro.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210609060910.1500481-1-jens.wiklander@linaro.org> References: <20210609060910.1500481-1-jens.wiklander@linaro.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210608_230922_318590_A9C3DFCD X-CRM114-Status: GOOD ( 20.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Adds tee_dev_open_helper() and tee_dev_ctx_put() to make it easier to create a driver internal struct tee_context without the usual tee_device_get() on the struct tee_device as that adds a circular reference counter dependency and would prevent the struct tee_device from ever being released again. Signed-off-by: Jens Wiklander --- drivers/tee/tee_core.c | 33 ++++++++++++++++++++++++--------- include/linux/tee_drv.h | 27 +++++++++++++++++++++++++++ 2 files changed, 51 insertions(+), 9 deletions(-) diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index f97d95b50773..6d81f6268b99 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -43,14 +43,11 @@ static DEFINE_SPINLOCK(driver_lock); static struct class *tee_class; static dev_t tee_devt; -static struct tee_context *teedev_open(struct tee_device *teedev) +struct tee_context *tee_dev_open_helper(struct tee_device *teedev) { int rc; struct tee_context *ctx; - if (!tee_device_get(teedev)) - return ERR_PTR(-EINVAL); - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) { rc = -ENOMEM; @@ -66,10 +63,30 @@ static struct tee_context *teedev_open(struct tee_device *teedev) return ctx; err: kfree(ctx); - tee_device_put(teedev); return ERR_PTR(rc); } +EXPORT_SYMBOL_GPL(tee_dev_open_helper); + +void tee_dev_ctx_put(struct tee_context *ctx) +{ + teedev_ctx_put(ctx); +} +EXPORT_SYMBOL_GPL(tee_dev_ctx_put); + +static struct tee_context *teedev_open(struct tee_device *teedev) +{ + struct tee_context *ctx; + + if (!tee_device_get(teedev)) + return ERR_PTR(-EINVAL); + + ctx = tee_dev_open_helper(teedev); + if (IS_ERR(ctx)) + tee_device_put(teedev); + + return ctx; +} void teedev_ctx_get(struct tee_context *ctx) { @@ -90,10 +107,8 @@ static void teedev_ctx_release(struct kref *ref) void teedev_ctx_put(struct tee_context *ctx) { - if (ctx->releasing) - return; - - kref_put(&ctx->refcount, teedev_ctx_release); + if (ctx && !ctx->releasing) + kref_put(&ctx->refcount, teedev_ctx_release); } static void teedev_close_context(struct tee_context *ctx) diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 54269e47ac9a..f592ba4e9561 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -456,6 +456,33 @@ static inline int tee_shm_get_id(struct tee_shm *shm) */ struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id); +/** + * tee_dev_open_helper() - helper function to make a struct tee_context + * @teedev: Device to open + * + * Creates the struct tee_context without increasing the reference counter + * on @teedev. This is needed for instance when a driver need an internal + * struct tee_context to operate on. By skipping the reference counter + * the circular dependency is broken. + * + * Note that this struct tee_context need special care when freeing in + * order to avoid the normal put on the struct tee_device. + * tee_dev_ctx_put() is the best choice for this. + * + * @returns a pointer 'struct tee_context' on success or an ERR_PTR on failure + */ +struct tee_context *tee_dev_open_helper(struct tee_device *teedev); + +/** + * tee_dev_ctx_put() - helper function to release a struct tee_context + * @ctx: The struct tee_context to release + * + * Note that this function doesn't do a tee_device_put() on the internal + * struct tee_device so this function should normal only be used when + * releasing a struct tee_context obtained with tee_dev_open_helper(). + */ +void tee_dev_ctx_put(struct tee_context *ctx); + /** * tee_client_open_context() - Open a TEE context * @start: if not NULL, continue search after this context