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Commit | Line | Data |
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ee08c6ec | 1 | #include <linux/kernel.h> |
bed1ffca | 2 | #include <linux/ftrace.h> |
ee08c6ec FW |
3 | #include <asm/syscall.h> |
4 | ||
5 | #include "trace_output.h" | |
6 | #include "trace.h" | |
7 | ||
8 | static atomic_t refcount; | |
9 | ||
bed1ffca FW |
10 | /* Our two options */ |
11 | enum { | |
12 | TRACE_SYSCALLS_OPT_TYPES = 0x1, | |
13 | }; | |
14 | ||
15 | static struct tracer_opt syscalls_opts[] = { | |
16 | { TRACER_OPT(syscall_arg_type, TRACE_SYSCALLS_OPT_TYPES) }, | |
17 | { } | |
18 | }; | |
19 | ||
20 | static struct tracer_flags syscalls_flags = { | |
21 | .val = 0, /* By default: no args types */ | |
22 | .opts = syscalls_opts | |
23 | }; | |
24 | ||
25 | enum print_line_t | |
26 | print_syscall_enter(struct trace_iterator *iter, int flags) | |
27 | { | |
28 | struct trace_seq *s = &iter->seq; | |
29 | struct trace_entry *ent = iter->ent; | |
30 | struct syscall_trace_enter *trace; | |
31 | struct syscall_metadata *entry; | |
32 | int i, ret, syscall; | |
33 | ||
34 | trace_assign_type(trace, ent); | |
35 | ||
36 | syscall = trace->nr; | |
37 | ||
38 | entry = syscall_nr_to_meta(syscall); | |
39 | if (!entry) | |
40 | goto end; | |
41 | ||
42 | ret = trace_seq_printf(s, "%s(", entry->name); | |
43 | if (!ret) | |
44 | return TRACE_TYPE_PARTIAL_LINE; | |
45 | ||
46 | for (i = 0; i < entry->nb_args; i++) { | |
47 | /* parameter types */ | |
48 | if (syscalls_flags.val & TRACE_SYSCALLS_OPT_TYPES) { | |
49 | ret = trace_seq_printf(s, "%s ", entry->types[i]); | |
50 | if (!ret) | |
51 | return TRACE_TYPE_PARTIAL_LINE; | |
52 | } | |
53 | /* parameter values */ | |
54 | ret = trace_seq_printf(s, "%s: %lx%s ", entry->args[i], | |
55 | trace->args[i], | |
56 | i == entry->nb_args - 1 ? ")" : ","); | |
57 | if (!ret) | |
58 | return TRACE_TYPE_PARTIAL_LINE; | |
59 | } | |
60 | ||
61 | end: | |
62 | trace_seq_printf(s, "\n"); | |
63 | return TRACE_TYPE_HANDLED; | |
64 | } | |
65 | ||
66 | enum print_line_t | |
67 | print_syscall_exit(struct trace_iterator *iter, int flags) | |
68 | { | |
69 | struct trace_seq *s = &iter->seq; | |
70 | struct trace_entry *ent = iter->ent; | |
71 | struct syscall_trace_exit *trace; | |
72 | int syscall; | |
73 | struct syscall_metadata *entry; | |
74 | int ret; | |
75 | ||
76 | trace_assign_type(trace, ent); | |
77 | ||
78 | syscall = trace->nr; | |
79 | ||
80 | entry = syscall_nr_to_meta(syscall); | |
81 | if (!entry) { | |
82 | trace_seq_printf(s, "\n"); | |
83 | return TRACE_TYPE_HANDLED; | |
84 | } | |
85 | ||
86 | ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name, | |
87 | trace->ret); | |
88 | if (!ret) | |
89 | return TRACE_TYPE_PARTIAL_LINE; | |
90 | ||
91 | return TRACE_TYPE_HANDLED; | |
92 | } | |
93 | ||
ee08c6ec FW |
94 | void start_ftrace_syscalls(void) |
95 | { | |
96 | unsigned long flags; | |
97 | struct task_struct *g, *t; | |
98 | ||
ac99c58c | 99 | /* Don't enable the flag on the tasks twice */ |
ee08c6ec | 100 | if (atomic_inc_return(&refcount) != 1) |
ac99c58c | 101 | return; |
ee08c6ec | 102 | |
bed1ffca | 103 | arch_init_ftrace_syscalls(); |
ee08c6ec FW |
104 | read_lock_irqsave(&tasklist_lock, flags); |
105 | ||
106 | do_each_thread(g, t) { | |
107 | set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE); | |
108 | } while_each_thread(g, t); | |
109 | ||
110 | read_unlock_irqrestore(&tasklist_lock, flags); | |
ee08c6ec FW |
111 | } |
112 | ||
113 | void stop_ftrace_syscalls(void) | |
114 | { | |
115 | unsigned long flags; | |
116 | struct task_struct *g, *t; | |
117 | ||
ac99c58c | 118 | /* There are perhaps still some users */ |
ee08c6ec | 119 | if (atomic_dec_return(&refcount)) |
ac99c58c | 120 | return; |
ee08c6ec FW |
121 | |
122 | read_lock_irqsave(&tasklist_lock, flags); | |
123 | ||
124 | do_each_thread(g, t) { | |
125 | clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE); | |
126 | } while_each_thread(g, t); | |
127 | ||
128 | read_unlock_irqrestore(&tasklist_lock, flags); | |
ee08c6ec FW |
129 | } |
130 | ||
131 | void ftrace_syscall_enter(struct pt_regs *regs) | |
132 | { | |
bed1ffca FW |
133 | struct syscall_trace_enter *entry; |
134 | struct syscall_metadata *sys_data; | |
135 | struct ring_buffer_event *event; | |
136 | int size; | |
ee08c6ec | 137 | int syscall_nr; |
bed1ffca | 138 | int cpu; |
ee08c6ec FW |
139 | |
140 | syscall_nr = syscall_get_nr(current, regs); | |
141 | ||
bed1ffca FW |
142 | cpu = raw_smp_processor_id(); |
143 | ||
144 | sys_data = syscall_nr_to_meta(syscall_nr); | |
145 | if (!sys_data) | |
146 | return; | |
147 | ||
148 | size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args; | |
149 | ||
150 | event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_ENTER, size, | |
151 | 0, 0); | |
152 | if (!event) | |
153 | return; | |
154 | ||
155 | entry = ring_buffer_event_data(event); | |
156 | entry->nr = syscall_nr; | |
157 | syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); | |
158 | ||
159 | trace_current_buffer_unlock_commit(event, 0, 0); | |
160 | trace_wake_up(); | |
ee08c6ec FW |
161 | } |
162 | ||
163 | void ftrace_syscall_exit(struct pt_regs *regs) | |
164 | { | |
bed1ffca FW |
165 | struct syscall_trace_exit *entry; |
166 | struct syscall_metadata *sys_data; | |
167 | struct ring_buffer_event *event; | |
ee08c6ec | 168 | int syscall_nr; |
bed1ffca | 169 | int cpu; |
ee08c6ec FW |
170 | |
171 | syscall_nr = syscall_get_nr(current, regs); | |
172 | ||
bed1ffca FW |
173 | cpu = raw_smp_processor_id(); |
174 | ||
175 | sys_data = syscall_nr_to_meta(syscall_nr); | |
176 | if (!sys_data) | |
177 | return; | |
178 | ||
179 | event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_EXIT, | |
180 | sizeof(*entry), 0, 0); | |
181 | if (!event) | |
182 | return; | |
183 | ||
184 | entry = ring_buffer_event_data(event); | |
185 | entry->nr = syscall_nr; | |
186 | entry->ret = syscall_get_return_value(current, regs); | |
187 | ||
188 | trace_current_buffer_unlock_commit(event, 0, 0); | |
189 | trace_wake_up(); | |
ee08c6ec FW |
190 | } |
191 | ||
192 | static int init_syscall_tracer(struct trace_array *tr) | |
193 | { | |
194 | start_ftrace_syscalls(); | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
199 | static void reset_syscall_tracer(struct trace_array *tr) | |
200 | { | |
201 | stop_ftrace_syscalls(); | |
ac99c58c | 202 | tracing_reset_online_cpus(tr); |
ee08c6ec FW |
203 | } |
204 | ||
205 | static struct trace_event syscall_enter_event = { | |
bed1ffca FW |
206 | .type = TRACE_SYSCALL_ENTER, |
207 | .trace = print_syscall_enter, | |
ee08c6ec FW |
208 | }; |
209 | ||
210 | static struct trace_event syscall_exit_event = { | |
bed1ffca FW |
211 | .type = TRACE_SYSCALL_EXIT, |
212 | .trace = print_syscall_exit, | |
ee08c6ec FW |
213 | }; |
214 | ||
215 | static struct tracer syscall_tracer __read_mostly = { | |
bed1ffca | 216 | .name = "syscall", |
ee08c6ec | 217 | .init = init_syscall_tracer, |
bed1ffca FW |
218 | .reset = reset_syscall_tracer, |
219 | .flags = &syscalls_flags, | |
ee08c6ec FW |
220 | }; |
221 | ||
222 | __init int register_ftrace_syscalls(void) | |
223 | { | |
224 | int ret; | |
225 | ||
226 | ret = register_ftrace_event(&syscall_enter_event); | |
227 | if (!ret) { | |
228 | printk(KERN_WARNING "event %d failed to register\n", | |
229 | syscall_enter_event.type); | |
230 | WARN_ON_ONCE(1); | |
231 | } | |
232 | ||
233 | ret = register_ftrace_event(&syscall_exit_event); | |
234 | if (!ret) { | |
235 | printk(KERN_WARNING "event %d failed to register\n", | |
236 | syscall_exit_event.type); | |
237 | WARN_ON_ONCE(1); | |
238 | } | |
239 | ||
240 | return register_tracer(&syscall_tracer); | |
241 | } | |
242 | device_initcall(register_ftrace_syscalls); |