1 files changed, 48 insertions, 2 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 140699a9a8a7..d6973dfadb36 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -32,6 +32,7 @@
 #include <trace/events/sched.h>
 
 #include <asm/ftrace.h>
+#include <asm/setup.h>
 
 #include "trace_output.h"
 #include "trace_stat.h"
@@ -598,7 +599,7 @@ function_profile_call(unsigned long ip, unsigned long parent_ip)
         local_irq_save(flags);
 
         stat = &__get_cpu_var(ftrace_profile_stats);
-        if (!stat->hash)
+        if (!stat->hash || !ftrace_profile_enabled)
                 goto out;
 
         rec = ftrace_find_profiled_func(stat, ip);
@@ -629,7 +630,7 @@ static void profile_graph_return(struct ftrace_graph_ret *trace)
 
         local_irq_save(flags);
         stat = &__get_cpu_var(ftrace_profile_stats);
-        if (!stat->hash)
+        if (!stat->hash || !ftrace_profile_enabled)
                 goto out;
 
         calltime = trace->rettime - trace->calltime;
@@ -723,6 +724,10 @@ ftrace_profile_write(struct file *filp, const char __user *ubuf,
                         ftrace_profile_enabled = 1;
                 } else {
                         ftrace_profile_enabled = 0;
+                        /*
+                         * unregister_ftrace_profiler calls stop_machine
+                         * so this acts like an synchronize_sched.
+                         */
                         unregister_ftrace_profiler();
                 }
         }
@@ -2369,6 +2374,45 @@ void ftrace_set_notrace(unsigned char *buf, int len, int reset)
         ftrace_set_regex(buf, len, reset, 0);
 }
 
+/*
+ * command line interface to allow users to set filters on boot up.
+ */
+#define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
+static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
+
+static int __init set_ftrace_notrace(char *str)
+{
+        strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+        return 1;
+}
+__setup("ftrace_notrace=", set_ftrace_notrace);
+
+static int __init set_ftrace_filter(char *str)
+{
+        strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+        return 1;
+}
+__setup("ftrace_filter=", set_ftrace_filter);
+
+static void __init set_ftrace_early_filter(char *buf, int enable)
+{
+        char *func;
+
+        while (buf) {
+                func = strsep(&buf, ",");
+                ftrace_set_regex(func, strlen(func), 0, enable);
+        }
+}
+
+static void __init set_ftrace_early_filters(void)
+{
+        if (ftrace_filter_buf[0])
+                set_ftrace_early_filter(ftrace_filter_buf, 1);
+        if (ftrace_notrace_buf[0])
+                set_ftrace_early_filter(ftrace_notrace_buf, 0);
+}
+
 static int
 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
 {
@@ -2829,6 +2873,8 @@ void __init ftrace_init(void)
         if (ret)
                 pr_warning("Failed to register trace ftrace module notifier\n");
 
+        set_ftrace_early_filters();
+
         return;
  failed:
         ftrace_disabled = 1;