From patchwork Mon Nov 9 12:56:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 322676 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 45C6FC56201 for ; Mon, 9 Nov 2020 13:26:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EED3F2076E for ; Mon, 9 Nov 2020 13:26:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604928410; bh=eWAXtWlHbL+UEXQDDC840B9t1tX3td866nAML6WaOj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=M/zHO/LnRsGHxojHGdHlh+UmsvRPHivYQFOmGhcsMJ5OGPj0pXcS5GaRvWfLZdr+g /NznRjEsJgex3hewDfpVHXlt2lQ/QvulyCQ0OmCGKaHlGVxPoYHHZFhLxlm4YchOtt bBoJPxpgOxXcty07KPYNiiKnNb5qML8yxGFxOVnk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732881AbgKINP2 (ORCPT ); Mon, 9 Nov 2020 08:15:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:42258 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732913AbgKINP1 (ORCPT ); Mon, 9 Nov 2020 08:15:27 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B3ECB208FE; Mon, 9 Nov 2020 13:15:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927726; bh=eWAXtWlHbL+UEXQDDC840B9t1tX3td866nAML6WaOj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jjA0cYZcIgDhtYB6KeB2u2eFZlxcJROQsNi2yJtCEaBO2zccDnWxCtQVqRlNIF6bt 1N60EeXBTXFmKLZMZcnnE13RWHql4tXI3t+utIVRG3PsXQ0O4PByuJ0CzBpQWLYEvW kQpbI18911t9AHNwlALWToyKrmXXtZHyzMuqxZhY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sasha Levin Subject: [PATCH 5.4 63/85] Revert "coresight: Make sysfs functional on topologies with per core sink" Date: Mon, 9 Nov 2020 13:56:00 +0100 Message-Id: <20201109125025.591630329@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125022.614792961@linuxfoundation.org> References: <20201109125022.614792961@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This reverts commit 8fd52a21ab570e80f84f39e12affce42a5300e91. Guenter Roeck writes: I get the following build warning in v5.4.75. drivers/hwtracing/coresight/coresight-etm-perf.c: In function 'etm_setup_aux': drivers/hwtracing/coresight/coresight-etm-perf.c:226:37: warning: passing argument 1 of 'coresight_get_enabled_sink' makes pointer from integer without a cast Actually, the warning is fatal, since the call is sink = coresight_get_enabled_sink(true); However, the argument to coresight_get_enabled_sink() is now a pointer. The parameter change was introduced with commit 8fd52a21ab57 ("coresight: Make sysfs functional on topologies with per core sink"). In the upstream kernel, the call is removed with commit bb1860efc817 ("coresight: etm: perf: Sink selection using sysfs is deprecated"). That commit alone would, however, likely not solve the problem. It looks like at least two more commits would be needed. 716f5652a131 coresight: etm: perf: Fix warning caused by etm_setup_aux failure 8e264c52e1da coresight: core: Allow the coresight core driver to be built as a module 39a7661dcf65 coresight: Fix uninitialised pointer bug in etm_setup_aux() Looking into the coresight code, I see several additional commits affecting the sysfs interface since v5.4. I have no idea what would actually be needed for stable code in v5.4.y, short of applying them all. With all this in mind, I would suggest to revert commit 8fd52a21ab57 ("coresight: Make sysfs functional on topologies with per core sink") from v5.4.y, especially since it is not marked as bug fix or for stable. Signed-off-by: Sasha Levin --- drivers/hwtracing/coresight/coresight-priv.h | 3 +- drivers/hwtracing/coresight/coresight.c | 62 +++++++++++--------- 2 files changed, 36 insertions(+), 29 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index dfd24b85a5775..82e563cdc8794 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -147,8 +147,7 @@ static inline void coresight_write_reg_pair(void __iomem *addr, u64 val, void coresight_disable_path(struct list_head *path); int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data); struct coresight_device *coresight_get_sink(struct list_head *path); -struct coresight_device * -coresight_get_enabled_sink(struct coresight_device *source); +struct coresight_device *coresight_get_enabled_sink(bool reset); struct coresight_device *coresight_get_sink_by_id(u32 id); struct list_head *coresight_build_path(struct coresight_device *csdev, struct coresight_device *sink); diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 90ecd04a2f20b..0bbce0d291582 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -481,46 +481,50 @@ struct coresight_device *coresight_get_sink(struct list_head *path) return csdev; } -static struct coresight_device * -coresight_find_enabled_sink(struct coresight_device *csdev) +static int coresight_enabled_sink(struct device *dev, const void *data) { - int i; - struct coresight_device *sink; + const bool *reset = data; + struct coresight_device *csdev = to_coresight_device(dev); if ((csdev->type == CORESIGHT_DEV_TYPE_SINK || csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) && - csdev->activated) - return csdev; - - /* - * Recursively explore each port found on this element. - */ - for (i = 0; i < csdev->pdata->nr_outport; i++) { - struct coresight_device *child_dev; + csdev->activated) { + /* + * Now that we have a handle on the sink for this session, + * disable the sysFS "enable_sink" flag so that possible + * concurrent perf session that wish to use another sink don't + * trip on it. Doing so has no ramification for the current + * session. + */ + if (*reset) + csdev->activated = false; - child_dev = csdev->pdata->conns[i].child_dev; - if (child_dev) - sink = coresight_find_enabled_sink(child_dev); - if (sink) - return sink; + return 1; } - return NULL; + return 0; } /** - * coresight_get_enabled_sink - returns the first enabled sink using - * connection based search starting from the source reference + * coresight_get_enabled_sink - returns the first enabled sink found on the bus + * @deactivate: Whether the 'enable_sink' flag should be reset * - * @source: Coresight source device reference + * When operated from perf the deactivate parameter should be set to 'true'. + * That way the "enabled_sink" flag of the sink that was selected can be reset, + * allowing for other concurrent perf sessions to choose a different sink. + * + * When operated from sysFS users have full control and as such the deactivate + * parameter should be set to 'false', hence mandating users to explicitly + * clear the flag. */ -struct coresight_device * -coresight_get_enabled_sink(struct coresight_device *source) +struct coresight_device *coresight_get_enabled_sink(bool deactivate) { - if (!source) - return NULL; + struct device *dev = NULL; + + dev = bus_find_device(&coresight_bustype, NULL, &deactivate, + coresight_enabled_sink); - return coresight_find_enabled_sink(source); + return dev ? to_coresight_device(dev) : NULL; } static int coresight_sink_by_id(struct device *dev, const void *data) @@ -760,7 +764,11 @@ int coresight_enable(struct coresight_device *csdev) goto out; } - sink = coresight_get_enabled_sink(csdev); + /* + * Search for a valid sink for this session but don't reset the + * "enable_sink" flag in sysFS. Users get to do that explicitly. + */ + sink = coresight_get_enabled_sink(false); if (!sink) { ret = -EINVAL; goto out;