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 extern int synth_event_run_command(const char *command);
 129
 130 static int __init
 131 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 132 {
 133         struct xbc_node *anode;
 134         char buf[MAX_BUF_LEN], *q;
 135         const char *p;
 136         int len, delta, ret;
 137
 138         len = ARRAY_SIZE(buf);
 139         delta = snprintf(buf, len, "%s", event);
 140         if (delta >= len) {
 141                 pr_err("Event name is too long: %s\n", event);
 142                 return -E2BIG;
 143         }
 144         len -= delta; q = buf + delta;
 145
 146         xbc_node_for_each_array_value(node, "fields", anode, p) {
 147                 delta = snprintf(q, len, " %s;", p);
 148                 if (delta >= len) {
 149                         pr_err("fields string is too long: %s\n", p);
 150                         return -E2BIG;
 151                 }
 152                 len -= delta; q += delta;
 153         }
 154
 155         ret = synth_event_run_command(buf);
 156         if (ret < 0)
 157                 pr_err("Failed to add synthetic event: %s\n", buf);
 158
 159
 160         return ret;
 161 }
 162 #else
 163 static inline int __init
 164 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 165 {
 166         pr_err("Synthetic event is not supported.\n");
 167         return -ENOTSUPP;
 168 }
 169 #endif
 170
 171 static void __init
 172 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
 173                           struct xbc_node *enode)
 174 {
 175         struct trace_event_file *file;
 176         struct xbc_node *anode;
 177         char buf[MAX_BUF_LEN];
 178         const char *p, *group, *event;
 179
 180         group = xbc_node_get_data(gnode);
 181         event = xbc_node_get_data(enode);
 182
 183         if (!strcmp(group, "kprobes"))
 184                 if (trace_boot_add_kprobe_event(enode, event) < 0)
 185                         return;
 186         if (!strcmp(group, "synthetic"))
 187                 if (trace_boot_add_synth_event(enode, event) < 0)
 188                         return;
 189
 190         mutex_lock(&event_mutex);
 191         file = find_event_file(tr, group, event);
 192         if (!file) {
 193                 pr_err("Failed to find event: %s:%s\n", group, event);
 194                 goto out;
 195         }
 196
 197         p = xbc_node_find_value(enode, "filter", NULL);
 198         if (p && *p != '\0') {
 199                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 200                         pr_err("filter string is too long: %s\n", p);
 201                 else if (apply_event_filter(file, buf) < 0)
 202                         pr_err("Failed to apply filter: %s\n", buf);
 203         }
 204
 205         xbc_node_for_each_array_value(enode, "actions", anode, p) {
 206                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 207                         pr_err("action string is too long: %s\n", p);
 208                 else if (trigger_process_regex(file, buf) < 0)
 209                         pr_err("Failed to apply an action: %s\n", buf);
 210         }
 211
 212         if (xbc_node_find_value(enode, "enable", NULL)) {
 213                 if (trace_event_enable_disable(file, 1, 0) < 0)
 214                         pr_err("Failed to enable event node: %s:%s\n",
 215                                 group, event);
 216         }
 217 out:
 218         mutex_unlock(&event_mutex);
 219 }
 220
 221 static void __init
 222 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
 223 {
 224         struct xbc_node *gnode, *enode;
 225
 226         node = xbc_node_find_child(node, "event");
 227         if (!node)
 228                 return;
 229         /* per-event key starts with "event.GROUP.EVENT" */
 230         xbc_node_for_each_child(node, gnode)
 231                 xbc_node_for_each_child(gnode, enode)
 232                         trace_boot_init_one_event(tr, gnode, enode);
 233 }
 234 #else
 235 #define trace_boot_enable_events(tr, node) do {} while (0)
 236 #define trace_boot_init_events(tr, node) do {} while (0)
 237 #endif
 238
 239 #ifdef CONFIG_DYNAMIC_FTRACE
 240 static void __init
 241 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
 242 {
 243         struct xbc_node *anode;
 244         const char *p;
 245         char *q;
 246
 247         xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
 248                 q = kstrdup(p, GFP_KERNEL);
 249                 if (!q)
 250                         return;
 251                 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
 252                         pr_err("Failed to add %s to ftrace filter\n", p);
 253                 else
 254                         ftrace_filter_param = true;
 255                 kfree(q);
 256         }
 257         xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
 258                 q = kstrdup(p, GFP_KERNEL);
 259                 if (!q)
 260                         return;
 261                 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
 262                         pr_err("Failed to add %s to ftrace filter\n", p);
 263                 else
 264                         ftrace_filter_param = true;
 265                 kfree(q);
 266         }
 267 }
 268 #else
 269 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
 270 #endif
 271
 272 static void __init
 273 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
 274 {
 275         const char *p;
 276
 277         trace_boot_set_ftrace_filter(tr, node);
 278
 279         p = xbc_node_find_value(node, "tracer", NULL);
 280         if (p && *p != '\0') {
 281                 if (tracing_set_tracer(tr, p) < 0)
 282                         pr_err("Failed to set given tracer: %s\n", p);
 283         }
 284 }
 285
 286 static void __init
 287 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
 288 {
 289         trace_boot_set_instance_options(tr, node);
 290         trace_boot_init_events(tr, node);
 291         trace_boot_enable_events(tr, node);
 292         trace_boot_enable_tracer(tr, node);
 293 }
 294
 295 static void __init
 296 trace_boot_init_instances(struct xbc_node *node)
 297 {
 298         struct xbc_node *inode;
 299         struct trace_array *tr;
 300         const char *p;
 301
 302         node = xbc_node_find_child(node, "instance");
 303         if (!node)
 304                 return;
 305
 306         xbc_node_for_each_child(node, inode) {
 307                 p = xbc_node_get_data(inode);
 308                 if (!p || *p == '\0')
 309                         continue;
 310
 311                 tr = trace_array_get_by_name(p);
 312                 if (!tr) {
 313                         pr_err("Failed to get trace instance %s\n", p);
 314                         continue;
 315                 }
 316                 trace_boot_init_one_instance(tr, inode);
 317                 trace_array_put(tr);
 318         }
 319 }
 320
 321 static int __init trace_boot_init(void)
 322 {
 323         struct xbc_node *trace_node;
 324         struct trace_array *tr;
 325
 326         trace_node = xbc_find_node("ftrace");
 327         if (!trace_node)
 328                 return 0;
 329
 330         tr = top_trace_array();
 331         if (!tr)
 332                 return 0;
 333
 334         /* Global trace array is also one instance */
 335         trace_boot_init_one_instance(tr, trace_node);
 336         trace_boot_init_instances(trace_node);
 337
 338         return 0;
 339 }
 340
 341 fs_initcall(trace_boot_init);