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[68.147.0.187]) by smtp.gmail.com with ESMTPSA id oa10sm964695pjb.54.2022.02.10.10.48.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Feb 2022 10:48:04 -0800 (PST) Date: Thu, 10 Feb 2022 11:48:02 -0700 From: Mathieu Poirier To: Puranjay Mohan Cc: puranjay12@gmail.com, kishon@ti.com, vigneshr@ti.com, s-anna@ti.com, bjorn.andersson@linaro.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4 1/2] remoteproc: Introduce deny_sysfs_ops flag Message-ID: <20220210184802.GB3603040@p14s> References: <20220209090342.13220-1-p-mohan@ti.com> <20220209090342.13220-2-p-mohan@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220209090342.13220-2-p-mohan@ti.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Puranjay, On Wed, Feb 09, 2022 at 02:33:41PM +0530, 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 '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. > > Implement attribute_group->is_visible() to hide the sysfs > state/firmware/recovery entries when deny_sysfs_ops flag is set. > > Signed-off-by: Puranjay Mohan > --- > 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 | 18 +++++++++++++++++- > include/linux/remoteproc.h | 2 ++ > 2 files changed, 19 insertions(+), 1 deletion(-) > > diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c > index ea8b89f97d7b..da2d0eecfa44 100644 > --- a/drivers/remoteproc/remoteproc_sysfs.c > +++ b/drivers/remoteproc/remoteproc_sysfs.c > @@ -230,6 +230,21 @@ 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->deny_sysfs_ops && (attr == &dev_attr_recovery.attr || > + attr == &dev_attr_firmware.attr || > + attr == &dev_attr_state.attr)) I was wondering if we should also add coredump to this group to make it an all or nothing option (name is already read only). > + mode = 0444; Much better. > + > + return mode; > +} > + > static struct attribute *rproc_attrs[] = { > &dev_attr_coredump.attr, > &dev_attr_recovery.attr, > @@ -240,7 +255,8 @@ 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..3849c66ce38f 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 > + * @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 > * @elf_class: firmware ELF class > @@ -562,6 +563,7 @@ struct rproc { > size_t table_sz; > bool has_iommu; > bool auto_boot; > + bool deny_sysfs_ops; Wouldn't "sysfs_read_only" make more sense? With or without the above and for this set: Reviewed-by: Mathieu Poirier > struct list_head dump_segments; > int nb_vdev; > u8 elf_class; > -- > 2.17.1 >