From b0fc494fae96a7089f3651cb451f461c7291244c Mon Sep 17 00:00:00 2001
From: Steven Rostedt
Date: Mon, 12 May 2008 21:20:43 +0200
Subject: ftrace: add ftrace_enabled sysctl to disable mcount function

This patch adds back the sysctl ftrace_enabled. This time it is
defaulted to on, if DYNAMIC_FTRACE is configured. When ftrace_enabled
is disabled, the ftrace function is set to the stub return.

If DYNAMIC_FTRACE is also configured, on ftrace_enabled = 0,
the registered ftrace functions will all be set to jmps, but no more
new calls to ftrace recording (used to find the ftrace calling sites)
will be called.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/sysctl.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'kernel/sysctl.c')

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 29116652dca8..efaf7c5500e9 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -46,6 +46,7 @@
 #include <linux/nfs_fs.h>
 #include <linux/acpi.h>
 #include <linux/reboot.h>
+#include <linux/ftrace.h>
 
 #include <asm/uaccess.h>
 #include <asm/processor.h>
@@ -455,6 +456,16 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec,
 	},
+#ifdef CONFIG_FTRACE
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "ftrace_enabled",
+		.data		= &ftrace_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &ftrace_enable_sysctl,
+	},
+#endif
 #ifdef CONFIG_KMOD
 	{
 		.ctl_name	= KERN_MODPROBE,
-- 
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