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 A7D87C433EF for ; Thu, 17 Feb 2022 06:14:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235225AbiBQGOh (ORCPT ); Thu, 17 Feb 2022 01:14:37 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:40418 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230254AbiBQGOh (ORCPT ); Thu, 17 Feb 2022 01:14:37 -0500 Received: from fllv0016.ext.ti.com (fllv0016.ext.ti.com [198.47.19.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24E1D2A2284; Wed, 16 Feb 2022 22:14:22 -0800 (PST) Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 21H6EEYB041371; Thu, 17 Feb 2022 00:14:14 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1645078454; bh=aLTZogrRpGo1Uu1bmA0UH4iVsPcFR2kuNZvj/aRW3Vw=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=F/+dQ9QTp4akMJ1cLEPJNXKg8PQKf3YgHg3DagIEJRct/7EB9Rw47liR/2UljsxwQ 5aAdBAyaw1YvJjw9lYOUfRorlAG3S7rCC3PTcOwKQ6nSMYQE9OXV4rBAeNC4DlyoU5 V7K3FNQpZHPHJNUR3FwdJOXk1h5JDVUijRWIsNls= Received: from DFLE112.ent.ti.com (dfle112.ent.ti.com [10.64.6.33]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 21H6EErd104575 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 17 Feb 2022 00:14:14 -0600 Received: from DFLE109.ent.ti.com (10.64.6.30) by DFLE112.ent.ti.com (10.64.6.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14; Thu, 17 Feb 2022 00:14:14 -0600 Received: from fllv0040.itg.ti.com (10.64.41.20) by DFLE109.ent.ti.com (10.64.6.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14 via Frontend Transport; Thu, 17 Feb 2022 00:14:13 -0600 Received: from [10.250.233.253] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0040.itg.ti.com (8.15.2/8.15.2) with ESMTP id 21H6E5NJ116873; Thu, 17 Feb 2022 00:14:06 -0600 Message-ID: Date: Thu, 17 Feb 2022 11:44:04 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v5 1/2] remoteproc: Introduce sysfs_read_only flag Content-Language: en-US To: Bjorn Andersson CC: , , , , , , References: <20220216081224.9956-1-p-mohan@ti.com> <20220216081224.9956-2-p-mohan@ti.com> From: Puranjay Mohan In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org Hi Bjorn, On 17/02/22 01:34, Bjorn Andersson wrote: > On Wed 16 Feb 02:12 CST 2022, Puranjay Mohan wrote: > >> The remoteproc framework provides sysfs interfaces for changing >> the firmware name and for starting/stopping a remote processor >> through the sysfs files 'state' and 'firmware'. The 'coredump' >> file is used to set the coredump configuration. The 'recovery' >> sysfs file can also be used similarly to control the error recovery >> state machine of a remoteproc. These interfaces are currently >> allowed irrespective of how the remoteprocs were booted (like >> remoteproc self auto-boot, remoteproc client-driven boot etc). >> These interfaces can adversely affect a remoteproc and its clients >> especially when a remoteproc is being controlled by a remoteproc >> client driver(s). Also, not all remoteproc drivers may want to >> support the sysfs interfaces by default. >> >> Add support to make the remoteproc sysfs files read only by >> introducing a state flag 'sysfs_read_only' that the individual >> remoteproc drivers can set based on their usage needs. The default >> behavior is to allow the sysfs operations as before. >> >> Implement attribute_group->is_visible() to make the sysfs >> entries read only when 'sysfs_read_only' flag is set. >> >> Signed-off-by: Puranjay Mohan >> Reviewed-by: Mathieu Poirier >> --- >> Changes in v4->v5: >> Rename deny_sysfs_ops to sysfs_read_only. >> Make coredump readonly with other files. >> >> Changes in v3->v4: >> Use mode = 0444 in rproc_is_visible() to make the sysfs entries >> read-only when the deny_sysfs_ops flag is set. >> --- >> drivers/remoteproc/remoteproc_sysfs.c | 19 ++++++++++++++++++- >> include/linux/remoteproc.h | 2 ++ >> 2 files changed, 20 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c >> index ea8b89f97d7b..abf0cd05d5e1 100644 >> --- a/drivers/remoteproc/remoteproc_sysfs.c >> +++ b/drivers/remoteproc/remoteproc_sysfs.c >> @@ -230,6 +230,22 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr, >> } >> static DEVICE_ATTR_RO(name); >> >> +static umode_t rproc_is_visible(struct kobject *kobj, struct attribute *attr, >> + int n) >> +{ >> + struct device *dev = kobj_to_dev(kobj); >> + struct rproc *rproc = to_rproc(dev); >> + umode_t mode = attr->mode; >> + >> + if (rproc->sysfs_read_only && (attr == &dev_attr_recovery.attr || >> + attr == &dev_attr_firmware.attr || >> + attr == &dev_attr_state.attr || >> + attr == &dev_attr_coredump.attr)) >> + mode = 0444; > > Change looks good now, but just to make sure, you actually care about > the content of these files for the Wakup M3? Read-only vs hiding them... Yes, it is useful for debugging purposes, hence making it read-only is the correct approach. Also, I will be re-sending PRU remoteproc consumer API patch series[1] that depends on this change. [1]https://patchwork.kernel.org/project/linux-remoteproc/cover/20201216165239.2744-1-grzegorz.jaszczyk@linaro.org/ Thanks, Puranjay Mohan > > regards, > Bjorn > >> + >> + return mode; >> +} >> + >> static struct attribute *rproc_attrs[] = { >> &dev_attr_coredump.attr, >> &dev_attr_recovery.attr, >> @@ -240,7 +256,8 @@ static struct attribute *rproc_attrs[] = { >> }; >> >> static const struct attribute_group rproc_devgroup = { >> - .attrs = rproc_attrs >> + .attrs = rproc_attrs, >> + .is_visible = rproc_is_visible, >> }; >> >> static const struct attribute_group *rproc_devgroups[] = { >> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h >> index e0600e1e5c17..93a1d0050fbc 100644 >> --- a/include/linux/remoteproc.h >> +++ b/include/linux/remoteproc.h >> @@ -523,6 +523,7 @@ struct rproc_dump_segment { >> * @table_sz: size of @cached_table >> * @has_iommu: flag to indicate if remote processor is behind an MMU >> * @auto_boot: flag to indicate if remote processor should be auto-started >> + * @sysfs_read_only: flag to make remoteproc sysfs files read only >> * @dump_segments: list of segments in the firmware >> * @nb_vdev: number of vdev currently handled by rproc >> * @elf_class: firmware ELF class >> @@ -562,6 +563,7 @@ struct rproc { >> size_t table_sz; >> bool has_iommu; >> bool auto_boot; >> + bool sysfs_read_only; >> struct list_head dump_segments; >> int nb_vdev; >> u8 elf_class; >> -- >> 2.17.1 >>