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[23.128.96.18]) by mx.google.com with ESMTP id j16si3750726edj.439.2020.11.20.19.48.42; Fri, 20 Nov 2020 19:49:05 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@ti.com header.s=ti-com-17Q1 header.b=n6GnvdCe; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=ti.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727347AbgKUDow (ORCPT + 99 others); Fri, 20 Nov 2020 22:44:52 -0500 Received: from fllv0015.ext.ti.com ([198.47.19.141]:58004 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726189AbgKUDov (ORCPT ); Fri, 20 Nov 2020 22:44:51 -0500 Received: from fllv0035.itg.ti.com ([10.64.41.0]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 0AL3ijoY094916; Fri, 20 Nov 2020 21:44:45 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1605930285; bh=mtcGcwe0UhnAjow/hTtbrFuVmQZBu7wLypOdw0kHT5c=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=n6GnvdCea1FI2LQXKeqjYGi7BbpzUPkF+1B6FjWrcIa8r92NHeJ+BWWk2YLI/Xjw7 iR3LZmR/PC7qRfEvdG1LmpgZiMrPAMfa2XgmmwcRUqw00fo51el3ViYuSdHaaWUqOs r7CB9gJcf8gQjEZuOIE/u+onZ1dE84XqVaN58QZY= Received: from DFLE107.ent.ti.com (dfle107.ent.ti.com [10.64.6.28]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 0AL3iiHF068496 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 20 Nov 2020 21:44:44 -0600 Received: from DFLE104.ent.ti.com (10.64.6.25) by DFLE107.ent.ti.com (10.64.6.28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Fri, 20 Nov 2020 21:44:44 -0600 Received: from fllv0040.itg.ti.com (10.64.41.20) by DFLE104.ent.ti.com (10.64.6.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Fri, 20 Nov 2020 21:44:44 -0600 Received: from [10.250.68.46] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0040.itg.ti.com (8.15.2/8.15.2) with ESMTP id 0AL3iiBl060339; Fri, 20 Nov 2020 21:44:44 -0600 Subject: Re: [PATCH v2 2/3] remoteproc: Introduce deny_sysfs_ops flag To: Bjorn Andersson CC: Mathieu Poirier , Arnaud Pouliquen , Loic Pallardy , Grzegorz Jaszczyk , Tony Lindgren , , , References: <20201121030156.22857-1-s-anna@ti.com> <20201121030156.22857-3-s-anna@ti.com> <20201121033810.GG9177@builder.lan> From: Suman Anna Message-ID: Date: Fri, 20 Nov 2020 21:44:44 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201121033810.GG9177@builder.lan> 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-kernel@vger.kernel.org On 11/20/20 9:38 PM, Bjorn Andersson wrote: > On Fri 20 Nov 21:01 CST 2020, Suman Anna 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 '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 deny the sysfs state/firmware/recovery change by >> introducing a state flag 'deny_sysfs_ops' that the individual >> remoteproc drivers can set based on their usage needs. The default >> behavior is to allow the sysfs operations as before. >> > > This makes sense, but can't we implement attribute_group->is_visible to > simply hide these entries from userspace instead of leaving them > "broken"? I would have to look into that, but can that be changed dynamically? Also, note that the enforcement is only on the writes/stores which impact the state-machine, but not the reads/shows. For PRU usecases, we will be setting this dynamically. regards Suman > > Regards, > Bjorn > >> Signed-off-by: Suman Anna >> --- >> v2: revised to account for the 'recovery' sysfs file as well, patch >> description updated accordingly >> v1: https://patchwork.kernel.org/project/linux-remoteproc/patch/20180915003725.17549-5-s-anna@ti.com/ >> >> drivers/remoteproc/remoteproc_sysfs.c | 12 ++++++++++++ >> include/linux/remoteproc.h | 2 ++ >> 2 files changed, 14 insertions(+) >> >> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c >> index bd2950a246c9..3fd18a71c188 100644 >> --- a/drivers/remoteproc/remoteproc_sysfs.c >> +++ b/drivers/remoteproc/remoteproc_sysfs.c >> @@ -49,6 +49,10 @@ static ssize_t recovery_store(struct device *dev, >> { >> struct rproc *rproc = to_rproc(dev); >> >> + /* restrict sysfs operations if not allowed by remoteproc drivers */ >> + if (rproc->deny_sysfs_ops) >> + return -EPERM; >> + >> if (sysfs_streq(buf, "enabled")) { >> /* change the flag and begin the recovery process if needed */ >> rproc->recovery_disabled = false; >> @@ -158,6 +162,10 @@ static ssize_t firmware_store(struct device *dev, >> char *p; >> int err, len = count; >> >> + /* restrict sysfs operations if not allowed by remoteproc drivers */ >> + if (rproc->deny_sysfs_ops) >> + return -EPERM; >> + >> err = mutex_lock_interruptible(&rproc->lock); >> if (err) { >> dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err); >> @@ -225,6 +233,10 @@ static ssize_t state_store(struct device *dev, >> struct rproc *rproc = to_rproc(dev); >> int ret = 0; >> >> + /* restrict sysfs operations if not allowed by remoteproc drivers */ >> + if (rproc->deny_sysfs_ops) >> + return -EPERM; >> + >> if (sysfs_streq(buf, "start")) { >> if (rproc->state == RPROC_RUNNING) >> return -EBUSY; >> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h >> index 3fa3ba6498e8..dbc3767f7d0e 100644 >> --- a/include/linux/remoteproc.h >> +++ b/include/linux/remoteproc.h >> @@ -508,6 +508,7 @@ struct rproc_dump_segment { >> * @has_iommu: flag to indicate if remote processor is behind an MMU >> * @auto_boot: flag to indicate if remote processor should be auto-started >> * @autonomous: true if an external entity has booted the remote processor >> + * @deny_sysfs_ops: flag to not permit sysfs operations on state, firmware and recovery >> * @dump_segments: list of segments in the firmware >> * @nb_vdev: number of vdev currently handled by rproc >> * @char_dev: character device of the rproc >> @@ -545,6 +546,7 @@ struct rproc { >> bool has_iommu; >> bool auto_boot; >> bool autonomous; >> + bool deny_sysfs_ops; >> struct list_head dump_segments; >> int nb_vdev; >> u8 elf_class; >> -- >> 2.28.0 >>