From patchwork Thu Aug 26 12:30:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Wiklander X-Patchwork-Id: 503009 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 81D62C4320A for ; Thu, 26 Aug 2021 12:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 608B5610C9 for ; Thu, 26 Aug 2021 12:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241822AbhHZMbf (ORCPT ); Thu, 26 Aug 2021 08:31:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241514AbhHZMbd (ORCPT ); Thu, 26 Aug 2021 08:31:33 -0400 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0A3DC0617AE for ; Thu, 26 Aug 2021 05:30:45 -0700 (PDT) Received: by mail-lj1-x236.google.com with SMTP id p15so4821171ljn.3 for ; Thu, 26 Aug 2021 05:30:45 -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=1nZh1D/vgfD/yG7MqBv8BFt2r+KBCfUf2rl9x11f65A=; b=kNBNiY4UKsmHZRbM99Vhd8h7GG/a9o6r1qngDP9tv1c2c7dYn161AjY9hvR9Wkg1xn B5RbLp9v662Oup9rkPC1iG6jTCQYctTlE+CP6c8SJWkudo6RgocexfxrpQOOczp3d36e iekhWD8PT/0u3JtFStgT83ARy+svf3XZWQYb6f3e+5xKNkRhkROtco7XdXzCnaaZRnCc pf12smkNjNNThPhq8hZq2e/WYQ5vu3MzeYNBhHsVf8VIpbjD6BBo1r37kplxKskrLyTK 1mPsykQL7M23aBamYB3QXlco98GP18j7T0+ed6iIq0biKyLckk5qNbFWiIr8BOGSWOfK upig== 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=1nZh1D/vgfD/yG7MqBv8BFt2r+KBCfUf2rl9x11f65A=; b=F5r5KwhPSBSJFzciNczFRy284shL/P9uC1Vc3WmweWJxVFOvdzk21dLxqwGxJC608O vXl1VB6qKmn63TI5AE3S+Hu19S91MqF+sVZjXI6s1hKWpduymSF1KvenGTUGfM/gnKRh ysqu5L5I/B31m+ZHR2oihD/dAb3s5ub8E05nDcpG52ulDMM4BitP23X6x2L7VDe5pytq HU8AGbzkNVSwq2ouO72oB5p9788DwGAuytzb8XPHSLLK8pIqM0rBm3ITCDjGlE0lS3sG Tk6AzOc2idNLygHeVOI/IrSpnFgtIC8+CfHYhFzm7weZRcm+Uf0b5Aba2daMCVlHPtHe 8jLQ== X-Gm-Message-State: AOAM531E6f7J5pG5uVWD2ZJxTXup4A3tsfR/6Gws7GK/rUJ2VNj/zV2x lS8QxsE9LwClQZxlWDrezTDRZw== X-Google-Smtp-Source: ABdhPJynXFjAEzvIhb7rgJmxnTlvzFE7/PKd9Xj72TVumnAIAtDL6snB6W6EV9yC3qBRMEbKSYXApQ== X-Received: by 2002:a2e:b042:: with SMTP id d2mr2881688ljl.279.1629981043906; Thu, 26 Aug 2021 05:30:43 -0700 (PDT) Received: from jade.ideon.se ([85.235.10.227]) by smtp.gmail.com with ESMTPSA id j21sm332283ljh.87.2021.08.26.05.30.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Aug 2021 05:30:43 -0700 (PDT) From: Jens Wiklander To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org Cc: Jerome Forissier , Etienne Carriere , Sumit Garg , Vincent Guittot , Rob Herring , Jonathan Corbet , Ard Biesheuvel , Marc Zyngier , Jens Wiklander Subject: [PATCH v5 4/6] tee: add tee_dev_open_helper() primitive Date: Thu, 26 Aug 2021 14:30:30 +0200 Message-Id: <20210826123032.1732926-5-jens.wiklander@linaro.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210826123032.1732926-1-jens.wiklander@linaro.org> References: <20210826123032.1732926-1-jens.wiklander@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.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 85102d12d716..3beb682684a8 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 3ebfea0781f1..00a31ff03049 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -458,6 +458,33 @@ 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