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Unverified Commit 72465736 authored by Mark Brown's avatar Mark Brown
Browse files

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: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 81e30b18

drivers/base/regmap/internal.h

+8 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/base/regmap/regmap-debugfs.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

drivers/base/regmap/regmap.c

+1 −0
Original line number Diff line number Diff line
@@ -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;