ee08c6eccb
Provide basic callbacks to do syscall tracing. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <1236401580-5758-2-git-send-email-fweisbec@gmail.com> [ simplified it to a trace_printk() for now. ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
113 lines
2.1 KiB
C
113 lines
2.1 KiB
C
#include <linux/ftrace.h>
|
|
#include <linux/kernel.h>
|
|
|
|
#include <asm/syscall.h>
|
|
|
|
#include "trace_output.h"
|
|
#include "trace.h"
|
|
|
|
static atomic_t refcount;
|
|
|
|
void start_ftrace_syscalls(void)
|
|
{
|
|
unsigned long flags;
|
|
struct task_struct *g, *t;
|
|
|
|
if (atomic_inc_return(&refcount) != 1)
|
|
goto out;
|
|
|
|
read_lock_irqsave(&tasklist_lock, flags);
|
|
|
|
do_each_thread(g, t) {
|
|
set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
|
|
} while_each_thread(g, t);
|
|
|
|
read_unlock_irqrestore(&tasklist_lock, flags);
|
|
out:
|
|
atomic_dec(&refcount);
|
|
}
|
|
|
|
void stop_ftrace_syscalls(void)
|
|
{
|
|
unsigned long flags;
|
|
struct task_struct *g, *t;
|
|
|
|
if (atomic_dec_return(&refcount))
|
|
goto out;
|
|
|
|
read_lock_irqsave(&tasklist_lock, flags);
|
|
|
|
do_each_thread(g, t) {
|
|
clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
|
|
} while_each_thread(g, t);
|
|
|
|
read_unlock_irqrestore(&tasklist_lock, flags);
|
|
out:
|
|
atomic_inc(&refcount);
|
|
}
|
|
|
|
void ftrace_syscall_enter(struct pt_regs *regs)
|
|
{
|
|
int syscall_nr;
|
|
|
|
syscall_nr = syscall_get_nr(current, regs);
|
|
|
|
trace_printk("syscall %d enter\n", syscall_nr);
|
|
}
|
|
|
|
void ftrace_syscall_exit(struct pt_regs *regs)
|
|
{
|
|
int syscall_nr;
|
|
|
|
syscall_nr = syscall_get_nr(current, regs);
|
|
|
|
trace_printk("syscall %d exit\n", syscall_nr);
|
|
}
|
|
|
|
static int init_syscall_tracer(struct trace_array *tr)
|
|
{
|
|
start_ftrace_syscalls();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void reset_syscall_tracer(struct trace_array *tr)
|
|
{
|
|
stop_ftrace_syscalls();
|
|
}
|
|
|
|
static struct trace_event syscall_enter_event = {
|
|
.type = TRACE_SYSCALL_ENTER,
|
|
};
|
|
|
|
static struct trace_event syscall_exit_event = {
|
|
.type = TRACE_SYSCALL_EXIT,
|
|
};
|
|
|
|
static struct tracer syscall_tracer __read_mostly = {
|
|
.name = "syscall",
|
|
.init = init_syscall_tracer,
|
|
.reset = reset_syscall_tracer
|
|
};
|
|
|
|
__init int register_ftrace_syscalls(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = register_ftrace_event(&syscall_enter_event);
|
|
if (!ret) {
|
|
printk(KERN_WARNING "event %d failed to register\n",
|
|
syscall_enter_event.type);
|
|
WARN_ON_ONCE(1);
|
|
}
|
|
|
|
ret = register_ftrace_event(&syscall_exit_event);
|
|
if (!ret) {
|
|
printk(KERN_WARNING "event %d failed to register\n",
|
|
syscall_exit_event.type);
|
|
WARN_ON_ONCE(1);
|
|
}
|
|
|
|
return register_tracer(&syscall_tracer);
|
|
}
|
|
device_initcall(register_ftrace_syscalls);
|