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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
24static void __init
25trace_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
82static void __init
83trace_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
101static int __init
102trace_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
129static inline int __init
130trace_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
138static int __init
139trace_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
166static inline int __init
167trace_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
174static void __init
175trace_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 }
223out:
224 mutex_unlock(&event_mutex);
225}
226
227static void __init
228trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
229{
230 struct xbc_node *gnode, *enode;
231 bool enable, enable_all = false;
232 const char *data;
233
234 node = xbc_node_find_child(node, "event");
235 if (!node)
236 return;
237 /* per-event key starts with "event.GROUP.EVENT" */
238 xbc_node_for_each_subkey(node, gnode) {
239 data = xbc_node_get_data(gnode);
240 if (!strcmp(data, "enable")) {
241 enable_all = true;
242 continue;
243 }
244 enable = false;
245 xbc_node_for_each_subkey(gnode, enode) {
246 data = xbc_node_get_data(enode);
247 if (!strcmp(data, "enable")) {
248 enable = true;
249 continue;
250 }
251 trace_boot_init_one_event(tr, gnode, enode);
252 }
253 /* Event enablement must be done after event settings */
254 if (enable) {
255 data = xbc_node_get_data(gnode);
256 trace_array_set_clr_event(tr, data, NULL, true);
257 }
258 }
259 /* Ditto */
260 if (enable_all)
261 trace_array_set_clr_event(tr, NULL, NULL, true);
262}
263#else
264#define trace_boot_enable_events(tr, node) do {} while (0)
265#define trace_boot_init_events(tr, node) do {} while (0)
266#endif
267
268#ifdef CONFIG_DYNAMIC_FTRACE
269static void __init
270trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
271{
272 struct xbc_node *anode;
273 const char *p;
274 char *q;
275
276 xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
277 q = kstrdup(p, GFP_KERNEL);
278 if (!q)
279 return;
280 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
281 pr_err("Failed to add %s to ftrace filter\n", p);
282 else
283 ftrace_filter_param = true;
284 kfree(q);
285 }
286 xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
287 q = kstrdup(p, GFP_KERNEL);
288 if (!q)
289 return;
290 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
291 pr_err("Failed to add %s to ftrace filter\n", p);
292 else
293 ftrace_filter_param = true;
294 kfree(q);
295 }
296}
297#else
298#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
299#endif
300
301static void __init
302trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
303{
304 const char *p;
305
306 trace_boot_set_ftrace_filter(tr, node);
307
308 p = xbc_node_find_value(node, "tracer", NULL);
309 if (p && *p != '\0') {
310 if (tracing_set_tracer(tr, p) < 0)
311 pr_err("Failed to set given tracer: %s\n", p);
312 }
313
314 /* Since tracer can free snapshot buffer, allocate snapshot here.*/
315 if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
316 if (tracing_alloc_snapshot_instance(tr) < 0)
317 pr_err("Failed to allocate snapshot buffer\n");
318 }
319}
320
321static void __init
322trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
323{
324 trace_boot_set_instance_options(tr, node);
325 trace_boot_init_events(tr, node);
326 trace_boot_enable_events(tr, node);
327 trace_boot_enable_tracer(tr, node);
328}
329
330static void __init
331trace_boot_init_instances(struct xbc_node *node)
332{
333 struct xbc_node *inode;
334 struct trace_array *tr;
335 const char *p;
336
337 node = xbc_node_find_child(node, "instance");
338 if (!node)
339 return;
340
341 xbc_node_for_each_subkey(node, inode) {
342 p = xbc_node_get_data(inode);
343 if (!p || *p == '\0')
344 continue;
345
346 tr = trace_array_get_by_name(p);
347 if (!tr) {
348 pr_err("Failed to get trace instance %s\n", p);
349 continue;
350 }
351 trace_boot_init_one_instance(tr, inode);
352 trace_array_put(tr);
353 }
354}
355
356static int __init trace_boot_init(void)
357{
358 struct xbc_node *trace_node;
359 struct trace_array *tr;
360
361 trace_node = xbc_find_node("ftrace");
362 if (!trace_node)
363 return 0;
364
365 tr = top_trace_array();
366 if (!tr)
367 return 0;
368
369 /* Global trace array is also one instance */
370 trace_boot_init_one_instance(tr, trace_node);
371 trace_boot_init_instances(trace_node);
372
373 disable_tracing_selftest("running boot-time tracing");
374
375 return 0;
376}
377/*
378 * Start tracing at the end of core-initcall, so that it starts tracing
379 * from the beginning of postcore_initcall.
380 */
381core_initcall_sync(trace_boot_init);