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, "trace_clock", NULL);
  44         if (p && *p != '\0') {
  45                 if (tracing_set_clock(tr, p) < 0)
  46                         pr_err("Failed to set trace clock: %s\n", p);
  47         }
  48
  49         p = xbc_node_find_value(node, "buffer_size", NULL);
  50         if (p && *p != '\0') {
  51                 v = memparse(p, NULL);
  52                 if (v < PAGE_SIZE)
  53                         pr_err("Buffer size is too small: %s\n", p);
  54                 if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
  55                         pr_err("Failed to resize trace buffer to %s\n", p);
  56         }
  57
  58         p = xbc_node_find_value(node, "cpumask", NULL);
  59         if (p && *p != '\0') {
  60                 cpumask_var_t new_mask;
  61
  62                 if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
  63                         if (cpumask_parse(p, new_mask) < 0 ||
  64                             tracing_set_cpumask(tr, new_mask) < 0)
  65                                 pr_err("Failed to set new CPU mask %s\n", p);
  66                         free_cpumask_var(new_mask);
  67                 }
  68         }
  69 }
  70
  71 #ifdef CONFIG_EVENT_TRACING
  72 static void __init
  73 trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
  74 {
  75         struct xbc_node *anode;
  76         char buf[MAX_BUF_LEN];
  77         const char *p;
  78
  79         xbc_node_for_each_array_value(node, "events", anode, p) {
  80                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
  81                         pr_err("String is too long: %s\n", p);
  82                         continue;
  83                 }
  84
  85                 if (ftrace_set_clr_event(tr, buf, 1) < 0)
  86                         pr_err("Failed to enable event: %s\n", p);
  87         }
  88 }
  89
  90 #ifdef CONFIG_KPROBE_EVENTS
  91 static int __init
  92 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
  93 {
  94         struct dynevent_cmd cmd;
  95         struct xbc_node *anode;
  96         char buf[MAX_BUF_LEN];
  97         const char *val;
  98         int ret;
  99
 100         kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
 101
 102         ret = kprobe_event_gen_cmd_start(&cmd, event, NULL);
 103         if (ret)
 104                 return ret;
 105
 106         xbc_node_for_each_array_value(node, "probes", anode, val) {
 107                 ret = kprobe_event_add_field(&cmd, val);
 108                 if (ret)
 109                         return ret;
 110         }
 111
 112         ret = kprobe_event_gen_cmd_end(&cmd);
 113         if (ret)
 114                 pr_err("Failed to add probe: %s\n", buf);
 115
 116         return ret;
 117 }
 118 #else
 119 static inline int __init
 120 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
 121 {
 122         pr_err("Kprobe event is not supported.\n");
 123         return -ENOTSUPP;
 124 }
 125 #endif
 126
 127 #ifdef CONFIG_HIST_TRIGGERS
 128 static int __init
 129 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 130 {
 131         struct dynevent_cmd cmd;
 132         struct xbc_node *anode;
 133         char buf[MAX_BUF_LEN];
 134         const char *p;
 135         int ret;
 136
 137         synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
 138
 139         ret = synth_event_gen_cmd_start(&cmd, event, NULL);
 140         if (ret)
 141                 return ret;
 142
 143         xbc_node_for_each_array_value(node, "fields", anode, p) {
 144                 ret = synth_event_add_field_str(&cmd, p);
 145                 if (ret)
 146                         return ret;
 147         }
 148
 149         ret = synth_event_gen_cmd_end(&cmd);
 150         if (ret < 0)
 151                 pr_err("Failed to add synthetic event: %s\n", buf);
 152
 153         return ret;
 154 }
 155 #else
 156 static inline int __init
 157 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 158 {
 159         pr_err("Synthetic event is not supported.\n");
 160         return -ENOTSUPP;
 161 }
 162 #endif
 163
 164 static void __init
 165 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
 166                           struct xbc_node *enode)
 167 {
 168         struct trace_event_file *file;
 169         struct xbc_node *anode;
 170         char buf[MAX_BUF_LEN];
 171         const char *p, *group, *event;
 172
 173         group = xbc_node_get_data(gnode);
 174         event = xbc_node_get_data(enode);
 175
 176         if (!strcmp(group, "kprobes"))
 177                 if (trace_boot_add_kprobe_event(enode, event) < 0)
 178                         return;
 179         if (!strcmp(group, "synthetic"))
 180                 if (trace_boot_add_synth_event(enode, event) < 0)
 181                         return;
 182
 183         mutex_lock(&event_mutex);
 184         file = find_event_file(tr, group, event);
 185         if (!file) {
 186                 pr_err("Failed to find event: %s:%s\n", group, event);
 187                 goto out;
 188         }
 189
 190         p = xbc_node_find_value(enode, "filter", NULL);
 191         if (p && *p != '\0') {
 192                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 193                         pr_err("filter string is too long: %s\n", p);
 194                 else if (apply_event_filter(file, buf) < 0)
 195                         pr_err("Failed to apply filter: %s\n", buf);
 196         }
 197
 198         xbc_node_for_each_array_value(enode, "actions", anode, p) {
 199                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 200                         pr_err("action string is too long: %s\n", p);
 201                 else if (trigger_process_regex(file, buf) < 0)
 202                         pr_err("Failed to apply an action: %s\n", buf);
 203         }
 204
 205         if (xbc_node_find_value(enode, "enable", NULL)) {
 206                 if (trace_event_enable_disable(file, 1, 0) < 0)
 207                         pr_err("Failed to enable event node: %s:%s\n",
 208                                 group, event);
 209         }
 210 out:
 211         mutex_unlock(&event_mutex);
 212 }
 213
 214 static void __init
 215 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
 216 {
 217         struct xbc_node *gnode, *enode;
 218
 219         node = xbc_node_find_child(node, "event");
 220         if (!node)
 221                 return;
 222         /* per-event key starts with "event.GROUP.EVENT" */
 223         xbc_node_for_each_child(node, gnode)
 224                 xbc_node_for_each_child(gnode, enode)
 225                         trace_boot_init_one_event(tr, gnode, enode);
 226 }
 227 #else
 228 #define trace_boot_enable_events(tr, node) do {} while (0)
 229 #define trace_boot_init_events(tr, node) do {} while (0)
 230 #endif
 231
 232 #ifdef CONFIG_DYNAMIC_FTRACE
 233 static void __init
 234 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
 235 {
 236         struct xbc_node *anode;
 237         const char *p;
 238         char *q;
 239
 240         xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
 241                 q = kstrdup(p, GFP_KERNEL);
 242                 if (!q)
 243                         return;
 244                 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
 245                         pr_err("Failed to add %s to ftrace filter\n", p);
 246                 else
 247                         ftrace_filter_param = true;
 248                 kfree(q);
 249         }
 250         xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
 251                 q = kstrdup(p, GFP_KERNEL);
 252                 if (!q)
 253                         return;
 254                 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
 255                         pr_err("Failed to add %s to ftrace filter\n", p);
 256                 else
 257                         ftrace_filter_param = true;
 258                 kfree(q);
 259         }
 260 }
 261 #else
 262 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
 263 #endif
 264
 265 static void __init
 266 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
 267 {
 268         const char *p;
 269
 270         trace_boot_set_ftrace_filter(tr, node);
 271
 272         p = xbc_node_find_value(node, "tracer", NULL);
 273         if (p && *p != '\0') {
 274                 if (tracing_set_tracer(tr, p) < 0)
 275                         pr_err("Failed to set given tracer: %s\n", p);
 276         }
 277 }
 278
 279 static void __init
 280 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
 281 {
 282         trace_boot_set_instance_options(tr, node);
 283         trace_boot_init_events(tr, node);
 284         trace_boot_enable_events(tr, node);
 285         trace_boot_enable_tracer(tr, node);
 286 }
 287
 288 static void __init
 289 trace_boot_init_instances(struct xbc_node *node)
 290 {
 291         struct xbc_node *inode;
 292         struct trace_array *tr;
 293         const char *p;
 294
 295         node = xbc_node_find_child(node, "instance");
 296         if (!node)
 297                 return;
 298
 299         xbc_node_for_each_child(node, inode) {
 300                 p = xbc_node_get_data(inode);
 301                 if (!p || *p == '\0')
 302                         continue;
 303
 304                 tr = trace_array_get_by_name(p);
 305                 if (!tr) {
 306                         pr_err("Failed to get trace instance %s\n", p);
 307                         continue;
 308                 }
 309                 trace_boot_init_one_instance(tr, inode);
 310                 trace_array_put(tr);
 311         }
 312 }
 313
 314 static int __init trace_boot_init(void)
 315 {
 316         struct xbc_node *trace_node;
 317         struct trace_array *tr;
 318
 319         trace_node = xbc_find_node("ftrace");
 320         if (!trace_node)
 321                 return 0;
 322
 323         tr = top_trace_array();
 324         if (!tr)
 325                 return 0;
 326
 327         /* Global trace array is also one instance */
 328         trace_boot_init_one_instance(tr, trace_node);
 329         trace_boot_init_instances(trace_node);
 330
 331         return 0;
 332 }
 333
 334 fs_initcall(trace_boot_init);