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 <[email protected]>
---
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..4a41abdd1f7b 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))
+ mode = 0;
+
+ 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;
struct list_head dump_segments;
int nb_vdev;
u8 elf_class;
--
2.24.3
Hi Bjorn,
On Fri, Feb 4, 2022 at 2:12 AM Bjorn Andersson
<[email protected]> wrote:
>
> On Thu 03 Feb 10:37 PST 2022, Mathieu Poirier wrote:
>
> > Hi Puranjay,
> >
> > On Mon, Jan 31, 2022 at 07:41:51PM +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.
> > >
> >
> > The address in the "To:" field of this email doesn't match the one in the SoB,
> > Something that makes checkpatch angry.
> >
> > > Signed-off-by: Puranjay Mohan <[email protected]>
> > > ---
> > > 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..4a41abdd1f7b 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 toyed with this solution for a little while. I think the use case is valid
> > but hiding the above options will also result in a system that is difficult to
> > use (and debug) because they convey important information.
> >
> > I suggest introducing a new kernel configuration options to make the attributes
> > of the rproc_devgroup return -EINVAL when it is set. So in remoteproc_sysfs.c
> > do something like:
> >
> > #if CONFIG_REMOTEPROC_SYSFS_RO
>
> We should assume that people runs the common multi_v7_defconfig for arm,
> or defconfig for arm64, and still want this support.
>
> Based on Puranjay's proposed patch I think it's also reasonable to
> assume that we might have platforms with a mixture of "read-only" and
> "normal" remoteprocs (e.g. some power-management uC + some DSP).
>
I will send another version with mode = 0444 in the .is_visible(), to
make it read-only when deny_sysfs_ops is true.
Also, this patch should technically be v3 as previous series ended with v2.
So, I will mark my next patch as v4.
Please let me know if any other changes are required to this patch.
> > static bool option_is_read_only()
> > {
> > return true;
> > }
> > #else
> > static bool option_is_read_only()
> > {
> > return false;
> > }
> > #endif
> >
> > [...]
> >
> > static ssize_t recovery_store(struct device *dev,
> > struct device_attribute *attr,
> > const char *buf, size_t count)
> > {
> > struct rproc *rproc = to_rproc(dev);
> >
> > if (option_is_read_only())
>
> struct attribute_group has a .is_visible callback which I think is
> better to base this on.
>
> Regards,
> Bjorn
>
> > return -EINVAL;
> >
> > if (sysfs_streq(buf, "enabled")) {
> > /* change the flag and begin the recovery process if needed */
> > rproc->recovery_disabled = false;
> > rproc_trigger_recovery(rproc);
> > } else if (sysfs_streq(buf, "disabled")) {
> > rproc->recovery_disabled = true;
> > } else if (sysfs_streq(buf, "recover")) {
> > /* begin the recovery process without changing the flag */
> > rproc_trigger_recovery(rproc);
> > } else {
> > return -EINVAL;
> > }
> >
> > return count;
> > }
> >
> > Thanks,
> > Mathieu
> >
> > > + mode = 0;
> > > +
> > > + 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;
> > > struct list_head dump_segments;
> > > int nb_vdev;
> > > u8 elf_class;
> > > --
> > > 2.24.3
> > >
Thanks,
Puranjay Mohan
On Fri, Feb 04, 2022 at 01:40:23AM +0530, Puranjay Mohan wrote:
> Hi Mathieu,
>
> On Fri, Feb 4, 2022 at 12:07 AM Mathieu Poirier
> <[email protected]> wrote:
> >
> > Hi Puranjay,
> >
> > On Mon, Jan 31, 2022 at 07:41:51PM +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.
> > >
> >
> > The address in the "To:" field of this email doesn't match the one in the SoB,
> > Something that makes checkpatch angry.
>
> I will try to figure this out.
>
> >
> > > Signed-off-by: Puranjay Mohan <[email protected]>
> > > ---
> > > 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..4a41abdd1f7b 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 toyed with this solution for a little while. I think the use case is valid
> > but hiding the above options will also result in a system that is difficult to
> > use (and debug) because they convey important information.
>
> I feel most use cases will require it to be read-only and not hidden,
> so, we can set mode = 0444 in place of mode = 0 below.
Perfect.
> It will make these files read-only without the extra code.
I haven't looked the specifics but even better if that is the case.
> Actually, the idea to implement is_visble() was given by Bjorn in a
> reply to the patch in the previous series[1].
>
I missed Bjorn's reply, which can happen given the high traffic on this mailing
list. And having different views on how to address problems is a good thing.
It gives us an opportunity to discuss different avenues and pick out the best
one.
> >
> > I suggest introducing a new kernel configuration options to make the attributes
>
> We want to do it dynamically and on a per driver basis, hence,
> implementing is_visble() would be apt, which can be controlled by the
> specific driver using the deny_sysfs_ops flag.
I agree that if you need that kind of granularity then a kernel configuration
option is not the right approach.
>
> > of the rproc_devgroup return -EINVAL when it is set. So in remoteproc_sysfs.c
> > do something like:
> >
> > #if CONFIG_REMOTEPROC_SYSFS_RO
> > static bool option_is_read_only()
> > {
> > return true;
> > }
> > #else
> > static bool option_is_read_only()
> > {
> > return false;
> > }
> > #endif
> >
> > [...]
> >
> > static ssize_t recovery_store(struct device *dev,
> > struct device_attribute *attr,
> > const char *buf, size_t count)
> > {
> > struct rproc *rproc = to_rproc(dev);
> >
> > if (option_is_read_only())
> > return -EINVAL;
> >
> > if (sysfs_streq(buf, "enabled")) {
> > /* change the flag and begin the recovery process if needed */
> > rproc->recovery_disabled = false;
> > rproc_trigger_recovery(rproc);
> > } else if (sysfs_streq(buf, "disabled")) {
> > rproc->recovery_disabled = true;
> > } else if (sysfs_streq(buf, "recover")) {
> > /* begin the recovery process without changing the flag */
> > rproc_trigger_recovery(rproc);
> > } else {
> > return -EINVAL;
> > }
> >
> > return count;
> > }
> >
> > Thanks,
> > Mathieu
> >
> > > + mode = 0;
>
> ^^ here we can put mode = 0444; for read-only.
>
> > > +
> > > + 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;
> > > struct list_head dump_segments;
> > > int nb_vdev;
> > > u8 elf_class;
> > > --
> > > 2.24.3
> > >
>
> [1] https://patchwork.kernel.org/project/linux-remoteproc/patch/[email protected]/
>
> Thanks,
> Puranjay Mohan
Hi Mathieu,
On Fri, Feb 4, 2022 at 12:07 AM Mathieu Poirier
<[email protected]> wrote:
>
> Hi Puranjay,
>
> On Mon, Jan 31, 2022 at 07:41:51PM +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.
> >
>
> The address in the "To:" field of this email doesn't match the one in the SoB,
> Something that makes checkpatch angry.
I will try to figure this out.
>
> > Signed-off-by: Puranjay Mohan <[email protected]>
> > ---
> > 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..4a41abdd1f7b 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 toyed with this solution for a little while. I think the use case is valid
> but hiding the above options will also result in a system that is difficult to
> use (and debug) because they convey important information.
I feel most use cases will require it to be read-only and not hidden,
so, we can set mode = 0444 in place of mode = 0 below.
It will make these files read-only without the extra code.
Actually, the idea to implement is_visble() was given by Bjorn in a
reply to the patch in the previous series[1].
>
> I suggest introducing a new kernel configuration options to make the attributes
We want to do it dynamically and on a per driver basis, hence,
implementing is_visble() would be apt, which can be controlled by the
specific driver using the deny_sysfs_ops flag.
> of the rproc_devgroup return -EINVAL when it is set. So in remoteproc_sysfs.c
> do something like:
>
> #if CONFIG_REMOTEPROC_SYSFS_RO
> static bool option_is_read_only()
> {
> return true;
> }
> #else
> static bool option_is_read_only()
> {
> return false;
> }
> #endif
>
> [...]
>
> static ssize_t recovery_store(struct device *dev,
> struct device_attribute *attr,
> const char *buf, size_t count)
> {
> struct rproc *rproc = to_rproc(dev);
>
> if (option_is_read_only())
> return -EINVAL;
>
> if (sysfs_streq(buf, "enabled")) {
> /* change the flag and begin the recovery process if needed */
> rproc->recovery_disabled = false;
> rproc_trigger_recovery(rproc);
> } else if (sysfs_streq(buf, "disabled")) {
> rproc->recovery_disabled = true;
> } else if (sysfs_streq(buf, "recover")) {
> /* begin the recovery process without changing the flag */
> rproc_trigger_recovery(rproc);
> } else {
> return -EINVAL;
> }
>
> return count;
> }
>
> Thanks,
> Mathieu
>
> > + mode = 0;
^^ here we can put mode = 0444; for read-only.
> > +
> > + 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;
> > struct list_head dump_segments;
> > int nb_vdev;
> > u8 elf_class;
> > --
> > 2.24.3
> >
[1] https://patchwork.kernel.org/project/linux-remoteproc/patch/[email protected]/
Thanks,
Puranjay Mohan
On Thu 03 Feb 10:37 PST 2022, Mathieu Poirier wrote:
> Hi Puranjay,
>
> On Mon, Jan 31, 2022 at 07:41:51PM +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.
> >
>
> The address in the "To:" field of this email doesn't match the one in the SoB,
> Something that makes checkpatch angry.
>
> > Signed-off-by: Puranjay Mohan <[email protected]>
> > ---
> > 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..4a41abdd1f7b 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 toyed with this solution for a little while. I think the use case is valid
> but hiding the above options will also result in a system that is difficult to
> use (and debug) because they convey important information.
>
> I suggest introducing a new kernel configuration options to make the attributes
> of the rproc_devgroup return -EINVAL when it is set. So in remoteproc_sysfs.c
> do something like:
>
> #if CONFIG_REMOTEPROC_SYSFS_RO
We should assume that people runs the common multi_v7_defconfig for arm,
or defconfig for arm64, and still want this support.
Based on Puranjay's proposed patch I think it's also reasonable to
assume that we might have platforms with a mixture of "read-only" and
"normal" remoteprocs (e.g. some power-management uC + some DSP).
> static bool option_is_read_only()
> {
> return true;
> }
> #else
> static bool option_is_read_only()
> {
> return false;
> }
> #endif
>
> [...]
>
> static ssize_t recovery_store(struct device *dev,
> struct device_attribute *attr,
> const char *buf, size_t count)
> {
> struct rproc *rproc = to_rproc(dev);
>
> if (option_is_read_only())
struct attribute_group has a .is_visible callback which I think is
better to base this on.
Regards,
Bjorn
> return -EINVAL;
>
> if (sysfs_streq(buf, "enabled")) {
> /* change the flag and begin the recovery process if needed */
> rproc->recovery_disabled = false;
> rproc_trigger_recovery(rproc);
> } else if (sysfs_streq(buf, "disabled")) {
> rproc->recovery_disabled = true;
> } else if (sysfs_streq(buf, "recover")) {
> /* begin the recovery process without changing the flag */
> rproc_trigger_recovery(rproc);
> } else {
> return -EINVAL;
> }
>
> return count;
> }
>
> Thanks,
> Mathieu
>
> > + mode = 0;
> > +
> > + 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;
> > struct list_head dump_segments;
> > int nb_vdev;
> > u8 elf_class;
> > --
> > 2.24.3
> >
Hi Puranjay,
On Mon, Jan 31, 2022 at 07:41:51PM +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.
>
The address in the "To:" field of this email doesn't match the one in the SoB,
Something that makes checkpatch angry.
> Signed-off-by: Puranjay Mohan <[email protected]>
> ---
> 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..4a41abdd1f7b 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 toyed with this solution for a little while. I think the use case is valid
but hiding the above options will also result in a system that is difficult to
use (and debug) because they convey important information.
I suggest introducing a new kernel configuration options to make the attributes
of the rproc_devgroup return -EINVAL when it is set. So in remoteproc_sysfs.c
do something like:
#if CONFIG_REMOTEPROC_SYSFS_RO
static bool option_is_read_only()
{
return true;
}
#else
static bool option_is_read_only()
{
return false;
}
#endif
[...]
static ssize_t recovery_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct rproc *rproc = to_rproc(dev);
if (option_is_read_only())
return -EINVAL;
if (sysfs_streq(buf, "enabled")) {
/* change the flag and begin the recovery process if needed */
rproc->recovery_disabled = false;
rproc_trigger_recovery(rproc);
} else if (sysfs_streq(buf, "disabled")) {
rproc->recovery_disabled = true;
} else if (sysfs_streq(buf, "recover")) {
/* begin the recovery process without changing the flag */
rproc_trigger_recovery(rproc);
} else {
return -EINVAL;
}
return count;
}
Thanks,
Mathieu
> + mode = 0;
> +
> + 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;
> struct list_head dump_segments;
> int nb_vdev;
> u8 elf_class;
> --
> 2.24.3
>