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[68.147.0.187]) by smtp.gmail.com with ESMTPSA id l20-20020a056a00141400b004f65cedfb09sm6451193pfu.48.2022.03.04.08.53.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Mar 2022 08:53:48 -0800 (PST) Date: Fri, 4 Mar 2022 09:53:46 -0700 From: Mathieu Poirier To: Puranjay Mohan Cc: Bjorn Andersson , Kishon Vijay Abraham I , vigneshr@ti.com, s-anna@ti.com, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [EXTERNAL] Re: [PATCH v5 1/2] remoteproc: Introduce sysfs_read_only flag Message-ID: <20220304165346.GA1646337@p14s> References: <20220216081224.9956-1-p-mohan@ti.com> <20220216081224.9956-2-p-mohan@ti.com> <0d44d73f-d882-83db-9cf2-09f7cdc91ab2@ti.com> <869aa1ad-e3ed-cd0b-ab5e-a4b7d1d23311@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <869aa1ad-e3ed-cd0b-ab5e-a4b7d1d23311@ti.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 03, 2022 at 01:30:08PM +0530, Puranjay Mohan wrote: > Hi Bjorn, > Hi Mathieu, > > When is this series expected to be applied? > > I am going to post another series titled "PRU Consumer API". > One patch from that series depends on this "Introduce sysfs_read_only > flag" patch. > > Please let me know so I can rebase and post that series. Applied and pushed. Thanks, Mathieu > > Thanks, > Puranjay Mohan > > On 18/02/22 11:24, Bjorn Andersson wrote: > > On Thu 17 Feb 21:00 PST 2022, Kishon Vijay Abraham I wrote: > > > >> > >> > >> 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 for the suggestion Kishon, but I like 0444, it has direct meaning > > to me. > > > > So unless there's some directive to use S_I*** throughout the kernel I > > would prefer this. > > > > Regards, > > Bjorn > > > >> 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; > >>>