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: 12459643 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=-17.5 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,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 A7948C432BE for ; Thu, 26 Aug 2021 12:33:18 +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 6EF646109E for ; Thu, 26 Aug 2021 12:33:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6EF646109E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=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=wLMs2y+mpy9tJ0/3jMrwqgefi7uHfzxzJ7P30ok++k8=; b=Lidq5UE1AQQXnI aIeow4dqG0QjY0E+oHcwNNfqGCcgj53OIpc03CBg8ZuNHjimxPlItVgMezg3/E+wMqHmCPY7kSikF 6dVrwV2YqSaQe8dMGifFsRly+5QzlhVp//RlSO89/KPb+iqNTjp+FJXitH8Nwb+6AicejJZRBfeHw CLQ4eQ+YXh1xetRgRkmMmDIQ2nRRIgImPty5KGTDAgJwxgNMla8/XAtuYsXSepep1whUWXRz+QVXB HhUU6HD013nxrdb4ECupFjs2qp+7NNaumrgyPZA4pVcAHrvPqQ3pS0YV6moTKbJQgyFA82IqfQxkt 5K5NnqrvmLxdHFZYFIrQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mJEXS-00A3zM-VZ; Thu, 26 Aug 2021 12:31:23 +0000 Received: from mail-lj1-x22d.google.com ([2a00:1450:4864:20::22d]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mJEWr-00A3qy-8m for linux-arm-kernel@lists.infradead.org; Thu, 26 Aug 2021 12:30:50 +0000 Received: by mail-lj1-x22d.google.com with SMTP id d16so4815494ljq.4 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=cSbclwX7S4dU56Zy24LreRO1veEnpiI1yA+F9Cec4rMcblxQG72EdlXm0hx9kqnH59 tcV/HNZvwNfRGxbmZrJ5931KB8YT+CyhcHlxO3gkr37Jp81xkx56NYYBiYLooDxksoSu 13tigKrsAQFrWPplHtiws1g1PKjogiOebs2hTyUBYdltrBcam5HKGMUxaMW6tLIMhwtv 7W7ABcWHchAzPlkslVFaUbbC18fACTFaPpTJG+2XACbuppiG9EZVrorHTAL1DiiNSL5I EtNb3KnasGA8c6QHBIjdo+J/wnKpq15vrzilrPXWrwo+GG80Xw4oYKwt7mFKcOnmUVrC J4jA== X-Gm-Message-State: AOAM533c9/vRF0gCthCERWHFjCqiHRsyzh1QR0q7xI5OortPY/a8kU2j /Hx1sk41UoicuD0EkfB8SJ3L+Q== 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210826_053045_335067_0871E118 X-CRM114-Status: GOOD ( 20.56 ) 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 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