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 99D5BC433EF for ; Fri, 18 Feb 2022 05:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230265AbiBRFBe (ORCPT ); Fri, 18 Feb 2022 00:01:34 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:48432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230294AbiBRFBO (ORCPT ); Fri, 18 Feb 2022 00:01:14 -0500 Received: from fllv0016.ext.ti.com (fllv0016.ext.ti.com [198.47.19.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CF6F1948C0; Thu, 17 Feb 2022 21:00:49 -0800 (PST) Received: from fllv0035.itg.ti.com ([10.64.41.0]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 21I50gcG048386; Thu, 17 Feb 2022 23:00:42 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1645160442; bh=XGAzAtgoKWZ6S5U7XK/NOYPT+W1ou+JL2nNvHqVts1Y=; h=Subject:To:References:From:Date:In-Reply-To; b=Ekk2BHG/TSnoRB7UpXvAJjV/RvPpFaQmHyEpXJ3pXG0suZVhkZXXTbsdDa6iCMXZN 7VmZNHMyxyIzjZEJ1BhJqCaAWXG6nvUtdfvTqgScoF6VRcYClk/Z2RwwBbGcWLTxHU ZtCixYKb4/ICcH6MOaXrUvYlUlGs4lQUiTa44PO0= Received: from DFLE111.ent.ti.com (dfle111.ent.ti.com [10.64.6.32]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 21I50gZG033477 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 17 Feb 2022 23:00:42 -0600 Received: from DFLE113.ent.ti.com (10.64.6.34) by DFLE111.ent.ti.com (10.64.6.32) 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 23:00:41 -0600 Received: from fllv0040.itg.ti.com (10.64.41.20) by DFLE113.ent.ti.com (10.64.6.34) 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 23:00:41 -0600 Received: from [10.250.233.137] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0040.itg.ti.com (8.15.2/8.15.2) with ESMTP id 21I50cmP087458; Thu, 17 Feb 2022 23:00:38 -0600 Subject: Re: [PATCH v5 1/2] remoteproc: Introduce sysfs_read_only flag To: Puranjay Mohan , , , , , , , References: <20220216081224.9956-1-p-mohan@ti.com> <20220216081224.9956-2-p-mohan@ti.com> From: Kishon Vijay Abraham I Message-ID: <0d44d73f-d882-83db-9cf2-09f7cdc91ab2@ti.com> Date: Fri, 18 Feb 2022 10:30:37 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20220216081224.9956-2-p-mohan@ti.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US 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 On 16/02/22 1:42 pm, 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; Nitpick: use S_IRUGO instead of 0444. Thanks, Kishon > + > + 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; >