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