From 72465736adf2aade263a9475a1d42007fd49e703 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 12 Dec 2017 16:56:43 +0000 Subject: [PATCH] regmap: Disable debugfs when locking is disabled The recently added support for disabling the regmap internal locking left debugfs enabled for devices with the locking disabled. This is a problem since debugfs allows userspace to do things like initiate reads from the hardware which will use the scratch buffers protected by the regmap locking so could cause data corruption. For safety address this by just disabling debugfs for these devices. That is overly conservative since some of the debugfs files just read internal data structures but it's much simpler to implmement and less likely to lead to problems with tooling that works with debugfs. Reported-by: Lars-Peter Clausen Signed-off-by: Mark Brown --- drivers/base/regmap/internal.h | 8 ++++++++ drivers/base/regmap/regmap-debugfs.c | 3 +++ drivers/base/regmap/regmap.c | 1 + 3 files changed, 12 insertions(+) diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h index 8641183cac2f..53785e0e297a 100644 --- a/drivers/base/regmap/internal.h +++ b/drivers/base/regmap/internal.h @@ -77,6 +77,7 @@ struct regmap { int async_ret; #ifdef CONFIG_DEBUG_FS + bool debugfs_disable; struct dentry *debugfs; const char *debugfs_name; @@ -215,10 +216,17 @@ struct regmap_field { extern void regmap_debugfs_initcall(void); extern void regmap_debugfs_init(struct regmap *map, const char *name); extern void regmap_debugfs_exit(struct regmap *map); + +static inline void regmap_debugfs_disable(struct regmap *map) +{ + map->debugfs_disable = true; +} + #else static inline void regmap_debugfs_initcall(void) { } static inline void regmap_debugfs_init(struct regmap *map, const char *name) { } static inline void regmap_debugfs_exit(struct regmap *map) { } +static inline void regmap_debugfs_disable(struct regmap *map) { } #endif /* regcache core declarations */ diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 36ce3511c733..c8ecefd75d6f 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -529,6 +529,9 @@ void regmap_debugfs_init(struct regmap *map, const char *name) struct regmap_range_node *range_node; const char *devname = "dummy"; + if (map->debugfs_disable) + return; + /* If we don't have the debugfs root yet, postpone init */ if (!regmap_debugfs_root) { struct regmap_debugfs_node *node; diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 54b1aa371c61..df9ca36753ff 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -676,6 +676,7 @@ struct regmap *__regmap_init(struct device *dev, if (config->disable_locking) { map->lock = map->unlock = regmap_lock_unlock_none; + regmap_debugfs_disable(map); } else if (config->lock && config->unlock) { map->lock = config->lock; map->unlock = config->unlock; -- GitLab