kernel/trace/trace_boot.c

   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
  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
  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
 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
 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
 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
 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
 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         xbc_node_for_each_array_value(enode, "actions", anode, p) {
 209                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 210                         pr_err("action string is too long: %s\n", p);
 211                 else if (trigger_process_regex(file, buf) < 0)
 212                         pr_err("Failed to apply an action: %s\n", buf);
 213         }
 214
 215         if (xbc_node_find_value(enode, "enable", NULL)) {
 216                 if (trace_event_enable_disable(file, 1, 0) < 0)
 217                         pr_err("Failed to enable event node: %s:%s\n",
 218                                 group, event);
 219         }
 220 out:
 221         mutex_unlock(&event_mutex);
 222 }
 223
 224 static void __init
 225 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
 226 {
 227         struct xbc_node *gnode, *enode;
 228         bool enable, enable_all = false;
 229         const char *data;
 230
 231         node = xbc_node_find_child(node, "event");
 232         if (!node)
 233                 return;
 234         /* per-event key starts with "event.GROUP.EVENT" */
 235         xbc_node_for_each_child(node, gnode) {
 236                 data = xbc_node_get_data(gnode);
 237                 if (!strcmp(data, "enable")) {
 238                         enable_all = true;
 239                         continue;
 240                 }
 241                 enable = false;
 242                 xbc_node_for_each_child(gnode, enode) {
 243                         data = xbc_node_get_data(enode);
 244                         if (!strcmp(data, "enable")) {
 245                                 enable = true;
 246                                 continue;
 247                         }
 248                         trace_boot_init_one_event(tr, gnode, enode);
 249                 }
 250                 /* Event enablement must be done after event settings */
 251                 if (enable) {
 252                         data = xbc_node_get_data(gnode);
 253                         trace_array_set_clr_event(tr, data, NULL, true);
 254                 }
 255         }
 256         /* Ditto */
 257         if (enable_all)
 258                 trace_array_set_clr_event(tr, NULL, NULL, true);
 259 }
 260 #else
 261 #define trace_boot_enable_events(tr, node) do {} while (0)
 262 #define trace_boot_init_events(tr, node) do {} while (0)
 263 #endif
 264
 265 #ifdef CONFIG_DYNAMIC_FTRACE
 266 static void __init
 267 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
 268 {
 269         struct xbc_node *anode;
 270         const char *p;
 271         char *q;
 272
 273         xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
 274                 q = kstrdup(p, GFP_KERNEL);
 275                 if (!q)
 276                         return;
 277                 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
 278                         pr_err("Failed to add %s to ftrace filter\n", p);
 279                 else
 280                         ftrace_filter_param = true;
 281                 kfree(q);
 282         }
 283         xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
 284                 q = kstrdup(p, GFP_KERNEL);
 285                 if (!q)
 286                         return;
 287                 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
 288                         pr_err("Failed to add %s to ftrace filter\n", p);
 289                 else
 290                         ftrace_filter_param = true;
 291                 kfree(q);
 292         }
 293 }
 294 #else
 295 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
 296 #endif
 297
 298 static void __init
 299 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
 300 {
 301         const char *p;
 302
 303         trace_boot_set_ftrace_filter(tr, node);
 304
 305         p = xbc_node_find_value(node, "tracer", NULL);
 306         if (p && *p != '\0') {
 307                 if (tracing_set_tracer(tr, p) < 0)
 308                         pr_err("Failed to set given tracer: %s\n", p);
 309         }
 310
 311         /* Since tracer can free snapshot buffer, allocate snapshot here.*/
 312         if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
 313                 if (tracing_alloc_snapshot_instance(tr) < 0)
 314                         pr_err("Failed to allocate snapshot buffer\n");
 315         }
 316 }
 317
 318 static void __init
 319 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
 320 {
 321         trace_boot_set_instance_options(tr, node);
 322         trace_boot_init_events(tr, node);
 323         trace_boot_enable_events(tr, node);
 324         trace_boot_enable_tracer(tr, node);
 325 }
 326
 327 static void __init
 328 trace_boot_init_instances(struct xbc_node *node)
 329 {
 330         struct xbc_node *inode;
 331         struct trace_array *tr;
 332         const char *p;
 333
 334         node = xbc_node_find_child(node, "instance");
 335         if (!node)
 336                 return;
 337
 338         xbc_node_for_each_child(node, inode) {
 339                 p = xbc_node_get_data(inode);
 340                 if (!p || *p == '\0')
 341                         continue;
 342
 343                 tr = trace_array_get_by_name(p);
 344                 if (!tr) {
 345                         pr_err("Failed to get trace instance %s\n", p);
 346                         continue;
 347                 }
 348                 trace_boot_init_one_instance(tr, inode);
 349                 trace_array_put(tr);
 350         }
 351 }
 352
 353 static int __init trace_boot_init(void)
 354 {
 355         struct xbc_node *trace_node;
 356         struct trace_array *tr;
 357
 358         trace_node = xbc_find_node("ftrace");
 359         if (!trace_node)
 360                 return 0;
 361
 362         tr = top_trace_array();
 363         if (!tr)
 364                 return 0;
 365
 366         /* Global trace array is also one instance */
 367         trace_boot_init_one_instance(tr, trace_node);
 368         trace_boot_init_instances(trace_node);
 369
 370         disable_tracing_selftest("running boot-time tracing");
 371
 372         return 0;
 373 }
 374 /*
 375  * Start tracing at the end of core-initcall, so that it starts tracing
 376  * from the beginning of postcore_initcall.
 377  */
 378 core_initcall_sync(trace_boot_init);