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 on the debugger.
Signed-off-by: Guilherme G. Piccoli <gpicc...@linux.vnet.ibm.com>
---
v2: dropped the custom parser by using simple attributes [mpe suggestion].
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 03f5d65..5f03b3c 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -29,6 +29,10 @@
#include <linux/nmi.h>
#include <linux/ctype.h>
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#endif
+
#include <asm/ptrace.h>
#include <asm/string.h>
#include <asm/prom.h>
@@ -3275,6 +3279,33 @@ 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_off = !val;
+ xmon_init(!xmon_off);
+
+ return 0;
+}
+
+static int xmon_dbgfs_get(void *data, u64 *val)
+{
+ *val = !xmon_off;
+ 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
