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/ftrace.h>
  10 #include <linux/init.h>
  11 #include <linux/bootconfig.h>
  12
  13 #include "trace.h"
  14
  15 #define MAX_BUF_LEN 256
  16
  17 extern int trace_set_options(struct trace_array *tr, char *option);
  18 extern int tracing_set_tracer(struct trace_array *tr, const char *buf);
  19 extern ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
  20                                           unsigned long size, int cpu_id);
  21 extern int tracing_set_cpumask(struct trace_array *tr,
  22                                 cpumask_var_t tracing_cpumask_new);
  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 extern int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set);
  73 extern int trigger_process_regex(struct trace_event_file *file, char *buff);
  74
  75 static void __init
  76 trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
  77 {
  78         struct xbc_node *anode;
  79         char buf[MAX_BUF_LEN];
  80         const char *p;
  81
  82         xbc_node_for_each_array_value(node, "events", anode, p) {
  83                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
  84                         pr_err("String is too long: %s\n", p);
  85                         continue;
  86                 }
  87
  88                 if (ftrace_set_clr_event(tr, buf, 1) < 0)
  89                         pr_err("Failed to enable event: %s\n", p);
  90         }
  91 }
  92
  93 #ifdef CONFIG_KPROBE_EVENTS
  94 extern int trace_kprobe_run_command(const char *command);
  95
  96 static int __init
  97 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
  98 {
  99         struct xbc_node *anode;
 100         char buf[MAX_BUF_LEN];
 101         const char *val;
 102         char *p;
 103         int len;
 104
 105         len = snprintf(buf, ARRAY_SIZE(buf) - 1, "p:kprobes/%s ", event);
 106         if (len >= ARRAY_SIZE(buf)) {
 107                 pr_err("Event name is too long: %s\n", event);
 108                 return -E2BIG;
 109         }
 110         p = buf + len;
 111         len = ARRAY_SIZE(buf) - len;
 112
 113         xbc_node_for_each_array_value(node, "probes", anode, val) {
 114                 if (strlcpy(p, val, len) >= len) {
 115                         pr_err("Probe definition is too long: %s\n", val);
 116                         return -E2BIG;
 117                 }
 118                 if (trace_kprobe_run_command(buf) < 0) {
 119                         pr_err("Failed to add probe: %s\n", buf);
 120                         return -EINVAL;
 121                 }
 122         }
 123
 124         return 0;
 125 }
 126 #else
 127 static inline int __init
 128 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
 129 {
 130         pr_err("Kprobe event is not supported.\n");
 131         return -ENOTSUPP;
 132 }
 133 #endif
 134
 135 #ifdef CONFIG_HIST_TRIGGERS
 136 extern int synth_event_run_command(const char *command);
 137
 138 static int __init
 139 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 140 {
 141         struct xbc_node *anode;
 142         char buf[MAX_BUF_LEN], *q;
 143         const char *p;
 144         int len, delta, ret;
 145
 146         len = ARRAY_SIZE(buf);
 147         delta = snprintf(buf, len, "%s", event);
 148         if (delta >= len) {
 149                 pr_err("Event name is too long: %s\n", event);
 150                 return -E2BIG;
 151         }
 152         len -= delta; q = buf + delta;
 153
 154         xbc_node_for_each_array_value(node, "fields", anode, p) {
 155                 delta = snprintf(q, len, " %s;", p);
 156                 if (delta >= len) {
 157                         pr_err("fields string is too long: %s\n", p);
 158                         return -E2BIG;
 159                 }
 160                 len -= delta; q += delta;
 161         }
 162
 163         ret = synth_event_run_command(buf);
 164         if (ret < 0)
 165                 pr_err("Failed to add synthetic event: %s\n", buf);
 166
 167
 168         return ret;
 169 }
 170 #else
 171 static inline int __init
 172 trace_boot_add_synth_event(struct xbc_node *node, const char *event)
 173 {
 174         pr_err("Synthetic event is not supported.\n");
 175         return -ENOTSUPP;
 176 }
 177 #endif
 178
 179 static void __init
 180 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
 181                           struct xbc_node *enode)
 182 {
 183         struct trace_event_file *file;
 184         struct xbc_node *anode;
 185         char buf[MAX_BUF_LEN];
 186         const char *p, *group, *event;
 187
 188         group = xbc_node_get_data(gnode);
 189         event = xbc_node_get_data(enode);
 190
 191         if (!strcmp(group, "kprobes"))
 192                 if (trace_boot_add_kprobe_event(enode, event) < 0)
 193                         return;
 194         if (!strcmp(group, "synthetic"))
 195                 if (trace_boot_add_synth_event(enode, event) < 0)
 196                         return;
 197
 198         mutex_lock(&event_mutex);
 199         file = find_event_file(tr, group, event);
 200         if (!file) {
 201                 pr_err("Failed to find event: %s:%s\n", group, event);
 202                 goto out;
 203         }
 204
 205         p = xbc_node_find_value(enode, "filter", NULL);
 206         if (p && *p != '\0') {
 207                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 208                         pr_err("filter string is too long: %s\n", p);
 209                 else if (apply_event_filter(file, buf) < 0)
 210                         pr_err("Failed to apply filter: %s\n", buf);
 211         }
 212
 213         xbc_node_for_each_array_value(enode, "actions", anode, p) {
 214                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 215                         pr_err("action string is too long: %s\n", p);
 216                 else if (trigger_process_regex(file, buf) < 0)
 217                         pr_err("Failed to apply an action: %s\n", buf);
 218         }
 219
 220         if (xbc_node_find_value(enode, "enable", NULL)) {
 221                 if (trace_event_enable_disable(file, 1, 0) < 0)
 222                         pr_err("Failed to enable event node: %s:%s\n",
 223                                 group, event);
 224         }
 225 out:
 226         mutex_unlock(&event_mutex);
 227 }
 228
 229 static void __init
 230 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
 231 {
 232         struct xbc_node *gnode, *enode;
 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_child(node, gnode)
 239                 xbc_node_for_each_child(gnode, enode)
 240                         trace_boot_init_one_event(tr, gnode, enode);
 241 }
 242 #else
 243 #define trace_boot_enable_events(tr, node) do {} while (0)
 244 #define trace_boot_init_events(tr, node) do {} while (0)
 245 #endif
 246
 247 #ifdef CONFIG_DYNAMIC_FTRACE
 248 extern bool ftrace_filter_param __initdata;
 249 extern int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 250                              int len, int reset);
 251 extern int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 252                               int len, int reset);
 253 static void __init
 254 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
 255 {
 256         struct xbc_node *anode;
 257         const char *p;
 258         char *q;
 259
 260         xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
 261                 q = kstrdup(p, GFP_KERNEL);
 262                 if (!q)
 263                         return;
 264                 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
 265                         pr_err("Failed to add %s to ftrace filter\n", p);
 266                 else
 267                         ftrace_filter_param = true;
 268                 kfree(q);
 269         }
 270         xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
 271                 q = kstrdup(p, GFP_KERNEL);
 272                 if (!q)
 273                         return;
 274                 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
 275                         pr_err("Failed to add %s to ftrace filter\n", p);
 276                 else
 277                         ftrace_filter_param = true;
 278                 kfree(q);
 279         }
 280 }
 281 #else
 282 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
 283 #endif
 284
 285 static void __init
 286 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
 287 {
 288         const char *p;
 289
 290         trace_boot_set_ftrace_filter(tr, node);
 291
 292         p = xbc_node_find_value(node, "tracer", NULL);
 293         if (p && *p != '\0') {
 294                 if (tracing_set_tracer(tr, p) < 0)
 295                         pr_err("Failed to set given tracer: %s\n", p);
 296         }
 297 }
 298
 299 static void __init
 300 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
 301 {
 302         trace_boot_set_instance_options(tr, node);
 303         trace_boot_init_events(tr, node);
 304         trace_boot_enable_events(tr, node);
 305         trace_boot_enable_tracer(tr, node);
 306 }
 307
 308 static void __init
 309 trace_boot_init_instances(struct xbc_node *node)
 310 {
 311         struct xbc_node *inode;
 312         struct trace_array *tr;
 313         const char *p;
 314
 315         node = xbc_node_find_child(node, "instance");
 316         if (!node)
 317                 return;
 318
 319         xbc_node_for_each_child(node, inode) {
 320                 p = xbc_node_get_data(inode);
 321                 if (!p || *p == '\0')
 322                         continue;
 323
 324                 tr = trace_array_get_by_name(p);
 325                 if (!tr) {
 326                         pr_err("Failed to get trace instance %s\n", p);
 327                         continue;
 328                 }
 329                 trace_boot_init_one_instance(tr, inode);
 330                 trace_array_put(tr);
 331         }
 332 }
 333
 334 static int __init trace_boot_init(void)
 335 {
 336         struct xbc_node *trace_node;
 337         struct trace_array *tr;
 338
 339         trace_node = xbc_find_node("ftrace");
 340         if (!trace_node)
 341                 return 0;
 342
 343         tr = top_trace_array();
 344         if (!tr)
 345                 return 0;
 346
 347         /* Global trace array is also one instance */
 348         trace_boot_init_one_instance(tr, trace_node);
 349         trace_boot_init_instances(trace_node);
 350
 351         return 0;
 352 }
 353
 354 fs_initcall(trace_boot_init);