diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index 252e5ef324e5..0dc2eb8e44e5 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -54,6 +54,9 @@ If you make a mistake with the syntax, the write will fail thus:: /dynamic_debug/control -bash: echo: write error: Invalid argument +Note, for systems without 'debugfs' enabled, the control file can be +found in ``/proc/dynamic_debug/control``. + Viewing Dynamic Debug Behaviour =============================== diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 69def4a9df00..7f4992fd8a2e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -98,7 +98,7 @@ config DYNAMIC_DEBUG 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 @@ config DYNAMIC_DEBUG 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: /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: diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index c60409138e13..aae17d9522e5 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -876,6 +876,14 @@ static const struct file_operations ddebug_proc_fops = { .write = ddebug_proc_write }; +static const struct proc_ops proc_fops = { + .proc_open = ddebug_proc_open, + .proc_read = seq_read, + .proc_lseek = seq_lseek, + .proc_release = seq_release_private, + .proc_write = ddebug_proc_write +}; + /* * Allocate a new ddebug_table for the given module * and add it to the global list. @@ -991,15 +999,25 @@ static void ddebug_remove_all_tables(void) static __initdata int ddebug_init_success; -static int __init dynamic_debug_init_debugfs(void) +static int __init dynamic_debug_init_control(void) { - struct dentry *dir; + struct proc_dir_entry *procfs_dir; + struct dentry *debugfs_dir; if (!ddebug_init_success) return -ENODEV; - dir = debugfs_create_dir("dynamic_debug", NULL); - debugfs_create_file("control", 0644, dir, NULL, &ddebug_proc_fops); + /* Create the control file in debugfs if it is enabled */ + if (debugfs_initialized()) { + debugfs_dir = debugfs_create_dir("dynamic_debug", NULL); + debugfs_create_file("control", 0644, debugfs_dir, NULL, + &ddebug_proc_fops); + } + + /* Also create the control file in procfs */ + procfs_dir = proc_mkdir("dynamic_debug", NULL); + if (procfs_dir) + proc_create("control", 0644, procfs_dir, &proc_fops); return 0; } @@ -1077,4 +1095,4 @@ out_err: early_initcall(dynamic_debug_init); /* Debugfs setup must be done later */ -fs_initcall(dynamic_debug_init_debugfs); +fs_initcall(dynamic_debug_init_control);