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 <p-mohan@xxxxxx>
> ---
> 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 <mathieu.poirier@xxxxxxxxxx>
> struct list_head dump_segments;
> int nb_vdev;
> u8 elf_class;
> --
> 2.17.1
>
