Re: [PATCH v2 0/3] Expose recovery/coredump configuration from sysfs

From: Arnaud POULIQUEN
Date: Tue Sep 15 2020 - 05:51:23 EST

Hi Rishabh,

On 8/27/20 9:48 PM, Rishabh Bhatnagar wrote:
> From Android R onwards Google has restricted access to debugfs in user
> and user-debug builds. This restricts access to most of the features
> exposed through debugfs. This patch series adds a configurable option
> to move the recovery/coredump interfaces to sysfs. If the feature
> flag is selected it would move these interfaces to sysfs and remove
> the equivalent debugfs interface. 'Coredump' and 'Recovery' are critical
> interfaces that are required for remoteproc to work on Qualcomm Chipsets.
> Coredump configuration needs to be set to "inline" in debug/test build
> and "disabled" in production builds. Whereas recovery needs to be
> "disabled" for debugging purposes and "enabled" on production builds.

The remoteproc_cdev had been created to respond to some sysfs limitations.
I wonder if this evolution should not also be implemented in the cdev.
In this case an additional event could be addedd to inform the application
that a crash occurred and that a core dump is available.

Of course it's only a suggestion... As it would be a redesign.
I let Björn and Mathieu comment.


> Changelog:
> v1 -> v2:
> - Correct the contact name in the sysfs documentation.
> - Remove the redundant write documentation for coredump/recovery sysfs
> - Add a feature flag to make this interface switch configurable.
> Rishabh Bhatnagar (3):
> remoteproc: Expose remoteproc configuration through sysfs
> remoteproc: Add coredump configuration to sysfs
> remoteproc: Add recovery configuration to sysfs
> Documentation/ABI/testing/sysfs-class-remoteproc | 44 ++++++++
> drivers/remoteproc/Kconfig | 12 +++
> drivers/remoteproc/remoteproc_debugfs.c | 10 +-
> drivers/remoteproc/remoteproc_sysfs.c | 126 +++++++++++++++++++++++
> 4 files changed, 190 insertions(+), 2 deletions(-)