From f4b5ffccc83c82947f5d9f15d6f1b6edb1b71cd7 Mon Sep 17 00:00:00 2001
From: Jason Baron <jbaron@redhat.com>
Date: Mon, 10 Aug 2009 16:53:02 -0400
Subject: tracing: Add perf counter support for syscalls tracing

The perf counter support is automated for usual trace events. But we
have to define specific callbacks for this to handle syscalls trace
events

Make 'perf stat -e syscalls:sys_enter_blah' work with syscall style
tracepoints.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 kernel/trace/trace_syscalls.c | 121 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

(limited to 'kernel/trace/trace_syscalls.c')

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index e58a9c11ba8..f4eaec3d559 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -1,6 +1,7 @@
 #include <trace/syscall.h>
 #include <linux/kernel.h>
 #include <linux/ftrace.h>
+#include <linux/perf_counter.h>
 #include <asm/syscall.h>
 
 #include "trace_output.h"
@@ -252,3 +253,123 @@ struct trace_event event_syscall_enter = {
 struct trace_event event_syscall_exit = {
 	.trace			= print_syscall_exit,
 };
+
+#ifdef CONFIG_EVENT_PROFILE
+static DECLARE_BITMAP(enabled_prof_enter_syscalls, FTRACE_SYSCALL_MAX);
+static DECLARE_BITMAP(enabled_prof_exit_syscalls, FTRACE_SYSCALL_MAX);
+static int sys_prof_refcount_enter;
+static int sys_prof_refcount_exit;
+
+static void prof_syscall_enter(struct pt_regs *regs, long id)
+{
+	struct syscall_metadata *sys_data;
+	int syscall_nr;
+
+	syscall_nr = syscall_get_nr(current, regs);
+	if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	perf_tpcounter_event(sys_data->enter_id, 0, 1, NULL, 0);
+}
+
+int reg_prof_syscall_enter(char *name)
+{
+	int ret = 0;
+	int num;
+
+	num = syscall_name_to_nr(name);
+	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+		return -ENOSYS;
+
+	mutex_lock(&syscall_trace_lock);
+	if (!sys_prof_refcount_enter)
+		ret = register_trace_syscall_enter(prof_syscall_enter);
+	if (ret) {
+		pr_info("event trace: Could not activate"
+				"syscall entry trace point");
+	} else {
+		set_bit(num, enabled_prof_enter_syscalls);
+		sys_prof_refcount_enter++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+void unreg_prof_syscall_enter(char *name)
+{
+	int num;
+
+	num = syscall_name_to_nr(name);
+	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+		return;
+
+	mutex_lock(&syscall_trace_lock);
+	sys_prof_refcount_enter--;
+	clear_bit(num, enabled_prof_enter_syscalls);
+	if (!sys_prof_refcount_enter)
+		unregister_trace_syscall_enter(prof_syscall_enter);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+static void prof_syscall_exit(struct pt_regs *regs, long ret)
+{
+	struct syscall_metadata *sys_data;
+	int syscall_nr;
+
+	syscall_nr = syscall_get_nr(current, regs);
+	if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	perf_tpcounter_event(sys_data->exit_id, 0, 1, NULL, 0);
+}
+
+int reg_prof_syscall_exit(char *name)
+{
+	int ret = 0;
+	int num;
+
+	num = syscall_name_to_nr(name);
+	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+		return -ENOSYS;
+
+	mutex_lock(&syscall_trace_lock);
+	if (!sys_prof_refcount_exit)
+		ret = register_trace_syscall_exit(prof_syscall_exit);
+	if (ret) {
+		pr_info("event trace: Could not activate"
+				"syscall entry trace point");
+	} else {
+		set_bit(num, enabled_prof_exit_syscalls);
+		sys_prof_refcount_exit++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+void unreg_prof_syscall_exit(char *name)
+{
+	int num;
+
+	num = syscall_name_to_nr(name);
+	if (num < 0 || num >= FTRACE_SYSCALL_MAX)
+		return;
+
+	mutex_lock(&syscall_trace_lock);
+	sys_prof_refcount_exit--;
+	clear_bit(num, enabled_prof_exit_syscalls);
+	if (!sys_prof_refcount_exit)
+		unregister_trace_syscall_exit(prof_syscall_exit);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+#endif
+
+
-- 
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