1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * trace_boot.c
4 * Tracing kernel boot-time
5 */
6
7 #define pr_fmt(fmt) "trace_boot: " fmt
8
9 #include <linux/bootconfig.h>
10 #include <linux/cpumask.h>
11 #include <linux/ftrace.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/mutex.h>
15 #include <linux/string.h>
16 #include <linux/slab.h>
17 #include <linux/trace.h>
18 #include <linux/trace_events.h>
19
20 #include "trace.h"
21
22 #define MAX_BUF_LEN 256
23
24 static void __init
trace_boot_set_instance_options(struct trace_array * tr,struct xbc_node * node)25 trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
26 {
27 struct xbc_node *anode;
28 const char *p;
29 char buf[MAX_BUF_LEN];
30 unsigned long v = 0;
31
32 /* Common ftrace options */
33 xbc_node_for_each_array_value(node, "options", anode, p) {
34 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
35 pr_err("String is too long: %s\n", p);
36 continue;
37 }
38
39 if (trace_set_options(tr, buf) < 0)
40 pr_err("Failed to set option: %s\n", buf);
41 }
42
43 p = xbc_node_find_value(node, "tracing_on", NULL);
44 if (p && *p != '\0') {
45 if (kstrtoul(p, 10, &v))
46 pr_err("Failed to set tracing on: %s\n", p);
47 if (v)
48 tracer_tracing_on(tr);
49 else
50 tracer_tracing_off(tr);
51 }
52
53 p = xbc_node_find_value(node, "trace_clock", NULL);
54 if (p && *p != '\0') {
55 if (tracing_set_clock(tr, p) < 0)
56 pr_err("Failed to set trace clock: %s\n", p);
57 }
58
59 p = xbc_node_find_value(node, "buffer_size", NULL);
60 if (p && *p != '\0') {
61 v = memparse(p, NULL);
62 if (v < PAGE_SIZE)
63 pr_err("Buffer size is too small: %s\n", p);
64 if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
65 pr_err("Failed to resize trace buffer to %s\n", p);
66 }
67
68 p = xbc_node_find_value(node, "cpumask", NULL);
69 if (p && *p != '\0') {
70 cpumask_var_t new_mask;
71
72 if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
73 if (cpumask_parse(p, new_mask) < 0 ||
74 tracing_set_cpumask(tr, new_mask) < 0)
75 pr_err("Failed to set new CPU mask %s\n", p);
76 free_cpumask_var(new_mask);
77 }
78 }
79 }
80
81 #ifdef CONFIG_EVENT_TRACING
82 static void __init
trace_boot_enable_events(struct trace_array * tr,struct xbc_node * node)83 trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
84 {
85 struct xbc_node *anode;
86 char buf[MAX_BUF_LEN];
87 const char *p;
88
89 xbc_node_for_each_array_value(node, "events", anode, p) {
90 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
91 pr_err("String is too long: %s\n", p);
92 continue;
93 }
94
95 if (ftrace_set_clr_event(tr, buf, 1) < 0)
96 pr_err("Failed to enable event: %s\n", p);
97 }
98 }
99
100 #ifdef CONFIG_KPROBE_EVENTS
101 static int __init
trace_boot_add_kprobe_event(struct xbc_node * node,const char * event)102 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
103 {
104 struct dynevent_cmd cmd;
105 struct xbc_node *anode;
106 char buf[MAX_BUF_LEN];
107 const char *val;
108 int ret = 0;
109
110 xbc_node_for_each_array_value(node, "probes", anode, val) {
111 kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
112
113 ret = kprobe_event_gen_cmd_start(&cmd, event, val);
114 if (ret) {
115 pr_err("Failed to generate probe: %s\n", buf);
116 break;
117 }
118
119 ret = kprobe_event_gen_cmd_end(&cmd);
120 if (ret) {
121 pr_err("Failed to add probe: %s\n", buf);
122 break;
123 }
124 }
125
126 return ret;
127 }
128 #else
129 static inline int __init
trace_boot_add_kprobe_event(struct xbc_node * node,const char * event)130 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
131 {
132 pr_err("Kprobe event is not supported.\n");
133 return -ENOTSUPP;
134 }
135 #endif
136
137 #ifdef CONFIG_SYNTH_EVENTS
138 static int __init
trace_boot_add_synth_event(struct xbc_node * node,const char * event)139 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
140 {
141 struct dynevent_cmd cmd;
142 struct xbc_node *anode;
143 char buf[MAX_BUF_LEN];
144 const char *p;
145 int ret;
146
147 synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
148
149 ret = synth_event_gen_cmd_start(&cmd, event, NULL);
150 if (ret)
151 return ret;
152
153 xbc_node_for_each_array_value(node, "fields", anode, p) {
154 ret = synth_event_add_field_str(&cmd, p);
155 if (ret)
156 return ret;
157 }
158
159 ret = synth_event_gen_cmd_end(&cmd);
160 if (ret < 0)
161 pr_err("Failed to add synthetic event: %s\n", buf);
162
163 return ret;
164 }
165 #else
166 static inline int __init
trace_boot_add_synth_event(struct xbc_node * node,const char * event)167 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
168 {
169 pr_err("Synthetic event is not supported.\n");
170 return -ENOTSUPP;
171 }
172 #endif
173
174 static void __init
trace_boot_init_one_event(struct trace_array * tr,struct xbc_node * gnode,struct xbc_node * enode)175 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
176 struct xbc_node *enode)
177 {
178 struct trace_event_file *file;
179 struct xbc_node *anode;
180 char buf[MAX_BUF_LEN];
181 const char *p, *group, *event;
182
183 group = xbc_node_get_data(gnode);
184 event = xbc_node_get_data(enode);
185
186 if (!strcmp(group, "kprobes"))
187 if (trace_boot_add_kprobe_event(enode, event) < 0)
188 return;
189 if (!strcmp(group, "synthetic"))
190 if (trace_boot_add_synth_event(enode, event) < 0)
191 return;
192
193 mutex_lock(&event_mutex);
194 file = find_event_file(tr, group, event);
195 if (!file) {
196 pr_err("Failed to find event: %s:%s\n", group, event);
197 goto out;
198 }
199
200 p = xbc_node_find_value(enode, "filter", NULL);
201 if (p && *p != '\0') {
202 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
203 pr_err("filter string is too long: %s\n", p);
204 else if (apply_event_filter(file, buf) < 0)
205 pr_err("Failed to apply filter: %s\n", buf);
206 }
207
208 if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
209 xbc_node_for_each_array_value(enode, "actions", anode, p) {
210 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
211 pr_err("action string is too long: %s\n", p);
212 else if (trigger_process_regex(file, buf) < 0)
213 pr_err("Failed to apply an action: %s\n", buf);
214 }
215 } else if (xbc_node_find_value(enode, "actions", NULL))
216 pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
217
218 if (xbc_node_find_value(enode, "enable", NULL)) {
219 if (trace_event_enable_disable(file, 1, 0) < 0)
220 pr_err("Failed to enable event node: %s:%s\n",
221 group, event);
222 }
223 out:
224 mutex_unlock(&event_mutex);
225 }
226
227 static void __init
trace_boot_init_events(struct trace_array * tr,struct xbc_node * node)228 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
229 {
230 struct xbc_node *gnode, *enode;
231
232 node = xbc_node_find_child(node, "event");
233 if (!node)
234 return;
235 /* per-event key starts with "event.GROUP.EVENT" */
236 xbc_node_for_each_subkey(node, gnode)
237 xbc_node_for_each_subkey(gnode, enode)
238 trace_boot_init_one_event(tr, gnode, enode);
239 }
240 #else
241 #define trace_boot_enable_events(tr, node) do {} while (0)
242 #define trace_boot_init_events(tr, node) do {} while (0)
243 #endif
244
245 #ifdef CONFIG_DYNAMIC_FTRACE
246 static void __init
trace_boot_set_ftrace_filter(struct trace_array * tr,struct xbc_node * node)247 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
248 {
249 struct xbc_node *anode;
250 const char *p;
251 char *q;
252
253 xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
254 q = kstrdup(p, GFP_KERNEL);
255 if (!q)
256 return;
257 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
258 pr_err("Failed to add %s to ftrace filter\n", p);
259 else
260 ftrace_filter_param = true;
261 kfree(q);
262 }
263 xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
264 q = kstrdup(p, GFP_KERNEL);
265 if (!q)
266 return;
267 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
268 pr_err("Failed to add %s to ftrace filter\n", p);
269 else
270 ftrace_filter_param = true;
271 kfree(q);
272 }
273 }
274 #else
275 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
276 #endif
277
278 static void __init
trace_boot_enable_tracer(struct trace_array * tr,struct xbc_node * node)279 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
280 {
281 const char *p;
282
283 trace_boot_set_ftrace_filter(tr, node);
284
285 p = xbc_node_find_value(node, "tracer", NULL);
286 if (p && *p != '\0') {
287 if (tracing_set_tracer(tr, p) < 0)
288 pr_err("Failed to set given tracer: %s\n", p);
289 }
290
291 /* Since tracer can free snapshot buffer, allocate snapshot here.*/
292 if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
293 if (tracing_alloc_snapshot_instance(tr) < 0)
294 pr_err("Failed to allocate snapshot buffer\n");
295 }
296 }
297
298 static void __init
trace_boot_init_one_instance(struct trace_array * tr,struct xbc_node * node)299 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
300 {
301 trace_boot_set_instance_options(tr, node);
302 trace_boot_init_events(tr, node);
303 trace_boot_enable_events(tr, node);
304 trace_boot_enable_tracer(tr, node);
305 }
306
307 static void __init
trace_boot_init_instances(struct xbc_node * node)308 trace_boot_init_instances(struct xbc_node *node)
309 {
310 struct xbc_node *inode;
311 struct trace_array *tr;
312 const char *p;
313
314 node = xbc_node_find_child(node, "instance");
315 if (!node)
316 return;
317
318 xbc_node_for_each_subkey(node, inode) {
319 p = xbc_node_get_data(inode);
320 if (!p || *p == '\0')
321 continue;
322
323 tr = trace_array_get_by_name(p);
324 if (!tr) {
325 pr_err("Failed to get trace instance %s\n", p);
326 continue;
327 }
328 trace_boot_init_one_instance(tr, inode);
329 trace_array_put(tr);
330 }
331 }
332
trace_boot_init(void)333 static int __init trace_boot_init(void)
334 {
335 struct xbc_node *trace_node;
336 struct trace_array *tr;
337
338 trace_node = xbc_find_node("ftrace");
339 if (!trace_node)
340 return 0;
341
342 tr = top_trace_array();
343 if (!tr)
344 return 0;
345
346 /* Global trace array is also one instance */
347 trace_boot_init_one_instance(tr, trace_node);
348 trace_boot_init_instances(trace_node);
349
350 disable_tracing_selftest("running boot-time tracing");
351
352 return 0;
353 }
354 /*
355 * Start tracing at the end of core-initcall, so that it starts tracing
356 * from the beginning of postcore_initcall.
357 */
358 core_initcall_sync(trace_boot_init);
359