1 #include <trace/syscall.h>
2 #include <linux/kernel.h>
3 #include <asm/syscall.h>
5 #include "trace_output.h"
8 /* Keep a counter of the syscall tracing users */
11 /* Prevent from races on thread flags toggling */
12 static DEFINE_MUTEX(syscall_trace_lock);
14 /* Option to display the parameters types */
16 TRACE_SYSCALLS_OPT_TYPES = 0x1,
19 static struct tracer_opt syscalls_opts[] = {
20 { TRACER_OPT(syscall_arg_type, TRACE_SYSCALLS_OPT_TYPES) },
24 static struct tracer_flags syscalls_flags = {
25 .val = 0, /* By default: no parameters types */
30 print_syscall_enter(struct trace_iterator *iter, int flags)
32 struct trace_seq *s = &iter->seq;
33 struct trace_entry *ent = iter->ent;
34 struct syscall_trace_enter *trace;
35 struct syscall_metadata *entry;
38 trace_assign_type(trace, ent);
42 entry = syscall_nr_to_meta(syscall);
46 ret = trace_seq_printf(s, "%s(", entry->name);
48 return TRACE_TYPE_PARTIAL_LINE;
50 for (i = 0; i < entry->nb_args; i++) {
52 if (syscalls_flags.val & TRACE_SYSCALLS_OPT_TYPES) {
53 ret = trace_seq_printf(s, "%s ", entry->types[i]);
55 return TRACE_TYPE_PARTIAL_LINE;
57 /* parameter values */
58 ret = trace_seq_printf(s, "%s: %lx%s ", entry->args[i],
60 i == entry->nb_args - 1 ? ")" : ",");
62 return TRACE_TYPE_PARTIAL_LINE;
66 trace_seq_printf(s, "\n");
67 return TRACE_TYPE_HANDLED;
71 print_syscall_exit(struct trace_iterator *iter, int flags)
73 struct trace_seq *s = &iter->seq;
74 struct trace_entry *ent = iter->ent;
75 struct syscall_trace_exit *trace;
77 struct syscall_metadata *entry;
80 trace_assign_type(trace, ent);
84 entry = syscall_nr_to_meta(syscall);
86 trace_seq_printf(s, "\n");
87 return TRACE_TYPE_HANDLED;
90 ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
93 return TRACE_TYPE_PARTIAL_LINE;
95 return TRACE_TYPE_HANDLED;
98 void start_ftrace_syscalls(void)
101 struct task_struct *g, *t;
103 mutex_lock(&syscall_trace_lock);
105 /* Don't enable the flag on the tasks twice */
109 read_lock_irqsave(&tasklist_lock, flags);
111 do_each_thread(g, t) {
112 set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
113 } while_each_thread(g, t);
115 read_unlock_irqrestore(&tasklist_lock, flags);
118 mutex_unlock(&syscall_trace_lock);
121 void stop_ftrace_syscalls(void)
124 struct task_struct *g, *t;
126 mutex_lock(&syscall_trace_lock);
128 /* There are perhaps still some users */
132 read_lock_irqsave(&tasklist_lock, flags);
134 do_each_thread(g, t) {
135 clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
136 } while_each_thread(g, t);
138 read_unlock_irqrestore(&tasklist_lock, flags);
141 mutex_unlock(&syscall_trace_lock);
144 void ftrace_syscall_enter(struct pt_regs *regs)
146 struct syscall_trace_enter *entry;
147 struct syscall_metadata *sys_data;
148 struct ring_buffer_event *event;
152 syscall_nr = syscall_get_nr(current, regs);
154 sys_data = syscall_nr_to_meta(syscall_nr);
158 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
160 event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_ENTER, size,
165 entry = ring_buffer_event_data(event);
166 entry->nr = syscall_nr;
167 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
169 trace_current_buffer_unlock_commit(event, 0, 0);
173 void ftrace_syscall_exit(struct pt_regs *regs)
175 struct syscall_trace_exit *entry;
176 struct syscall_metadata *sys_data;
177 struct ring_buffer_event *event;
180 syscall_nr = syscall_get_nr(current, regs);
182 sys_data = syscall_nr_to_meta(syscall_nr);
186 event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_EXIT,
187 sizeof(*entry), 0, 0);
191 entry = ring_buffer_event_data(event);
192 entry->nr = syscall_nr;
193 entry->ret = syscall_get_return_value(current, regs);
195 trace_current_buffer_unlock_commit(event, 0, 0);
199 static int init_syscall_tracer(struct trace_array *tr)
201 start_ftrace_syscalls();
206 static void reset_syscall_tracer(struct trace_array *tr)
208 stop_ftrace_syscalls();
209 tracing_reset_online_cpus(tr);
212 static struct trace_event syscall_enter_event = {
213 .type = TRACE_SYSCALL_ENTER,
214 .trace = print_syscall_enter,
217 static struct trace_event syscall_exit_event = {
218 .type = TRACE_SYSCALL_EXIT,
219 .trace = print_syscall_exit,
222 static struct tracer syscall_tracer __read_mostly = {
224 .init = init_syscall_tracer,
225 .reset = reset_syscall_tracer,
226 .flags = &syscalls_flags,
229 __init int register_ftrace_syscalls(void)
233 ret = register_ftrace_event(&syscall_enter_event);
235 printk(KERN_WARNING "event %d failed to register\n",
236 syscall_enter_event.type);
240 ret = register_ftrace_event(&syscall_exit_event);
242 printk(KERN_WARNING "event %d failed to register\n",
243 syscall_exit_event.type);
247 return register_tracer(&syscall_tracer);
249 device_initcall(register_ftrace_syscalls);