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'. 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 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. Signed-off-by: Suman Anna <[email protected]> --- drivers/remoteproc/remoteproc_sysfs.c | 8 ++++++++ include/linux/remoteproc.h | 2 ++ 2 files changed, 10 insertions(+) diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c index ce93f4d710f3..b2d8c11b89d0 100644 --- a/drivers/remoteproc/remoteproc_sysfs.c +++ b/drivers/remoteproc/remoteproc_sysfs.c @@ -36,6 +36,10 @@ static ssize_t firmware_store(struct device *dev, char *p; int err, len = count; + /* restrict sysfs operations if not allowed by remoteproc drivers */ + if (rproc->deny_sysfs_ops) + return -EPERM; + err = mutex_lock_interruptible(&rproc->lock); if (err) { dev_err(dev, "can't lock rproc %s: %d\n", rproc->name, err); @@ -102,6 +106,10 @@ static ssize_t state_store(struct device *dev, struct rproc *rproc = to_rproc(dev); int ret = 0; + /* restrict sysfs operations if not allowed by remoteproc drivers */ + if (rproc->deny_sysfs_ops) + return -EPERM; + if (sysfs_streq(buf, "start")) { if (rproc->state == RPROC_RUNNING) return -EBUSY; diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h index 75f9ca05b865..d21252b4f758 100644 --- a/include/linux/remoteproc.h +++ b/include/linux/remoteproc.h @@ -440,6 +440,7 @@ 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 and firmware * @dump_segments: list of segments in the firmware */ struct rproc { @@ -472,6 +473,7 @@ struct rproc { size_t table_sz; bool has_iommu; bool auto_boot; + bool deny_sysfs_ops; struct list_head dump_segments; }; -- 2.18.0
