dynamic_debug: allow to work if debugfs is disabled
With the realization that having debugfs enabled on "production" systems
is generally not a good idea, debugfs is being disabled from more and
more platforms over time. However, the functionality of dynamic
debugging still is needed at times, and since it relies on debugfs for
its user api, having debugfs disabled also forces dynamic debug to be
disabled.
To get around this, also create the "control" file for dynamic_debug in
procfs. This allows people turn on debugging as needed at runtime for
individual driverfs and subsystems.
Reported-by: many different companies
Cc: Jason Baron <jbaron@akamai.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200210211142.GB1373304@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 69def4a..7f4992f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -98,7 +98,7 @@
bool "Enable dynamic printk() support"
default n
depends on PRINTK
- depends on DEBUG_FS
+ depends on (DEBUG_FS || PROC_FS)
help
Compiles debug level messages into the kernel, which would not
@@ -116,8 +116,9 @@
Usage:
Dynamic debugging is controlled via the 'dynamic_debug/control' file,
- which is contained in the 'debugfs' filesystem. Thus, the debugfs
- filesystem must first be mounted before making use of this feature.
+ which is contained in the 'debugfs' filesystem or procfs.
+ Thus, the debugfs or procfs filesystem must first be mounted before
+ making use of this feature.
We refer the control file as: <debugfs>/dynamic_debug/control. This
file contains a list of the debug statements that can be enabled. The
format for each line of the file is: