From de78ae6c9ef55d9ded036c8e29d9364e1ce5f6b7 Mon Sep 17 00:00:00 2001 From: "Guilherme G. Piccoli" Date: Wed, 22 Mar 2017 16:27:51 -0300 Subject: [PATCH] powerpc/xmon: add debugfs entry for xmon Currently the xmon debugger is set only via kernel boot command-line. It's disabled by default, and can be enabled with "xmon=on" on the command-line. Also, xmon may be accessed via sysrq mechanism. But we cannot enable/disable xmon in runtime, it needs kernel reload. This patch introduces a debugfs entry for xmon, allowing user to query its current state and change it if desired. Basically, the "xmon" file to read from/write to is under the debugfs mount point, on powerpc directory. It's a simple attribute, value 0 meaning xmon is disabled and value 1 the opposite. Writing these states to the file will take immediate effect in the debugger. Signed-off-by: Guilherme G. Piccoli Signed-off-by: Michael Ellerman --- arch/powerpc/xmon/xmon.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 25a3281..0fab9d7 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -29,6 +29,10 @@ #include #include +#ifdef CONFIG_DEBUG_FS +#include +#endif + #include #include #include @@ -3316,6 +3320,33 @@ static int __init setup_xmon_sysrq(void) device_initcall(setup_xmon_sysrq); #endif /* CONFIG_MAGIC_SYSRQ */ +#ifdef CONFIG_DEBUG_FS +static int xmon_dbgfs_set(void *data, u64 val) +{ + xmon_on = !!val; + xmon_init(xmon_on); + + return 0; +} + +static int xmon_dbgfs_get(void *data, u64 *val) +{ + *val = xmon_on; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(xmon_dbgfs_ops, xmon_dbgfs_get, + xmon_dbgfs_set, "%llu\n"); + +static int __init setup_xmon_dbgfs(void) +{ + debugfs_create_file("xmon", 0600, powerpc_debugfs_root, NULL, + &xmon_dbgfs_ops); + return 0; +} +device_initcall(setup_xmon_dbgfs); +#endif /* CONFIG_DEBUG_FS */ + static int xmon_early __initdata; static int __init early_parse_xmon(char *p) -- 2.7.4