// SPDX-License-Identifier: GPL-2.0
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/*
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* trace_boot.c
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* Tracing kernel boot-time
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*/
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#define pr_fmt(fmt) "trace_boot: " fmt
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#include <linux/bootconfig.h>
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#include <linux/cpumask.h>
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#include <linux/ftrace.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/mutex.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/trace.h>
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#include <linux/trace_events.h>
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#include "trace.h"
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#define MAX_BUF_LEN 256
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static void __init
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trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *anode;
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const char *p;
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char buf[MAX_BUF_LEN];
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unsigned long v = 0;
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/* Common ftrace options */
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xbc_node_for_each_array_value(node, "options", anode, p) {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
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pr_err("String is too long: %s\n", p);
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continue;
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}
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if (trace_set_options(tr, buf) < 0)
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pr_err("Failed to set option: %s\n", buf);
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}
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p = xbc_node_find_value(node, "tracing_on", NULL);
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if (p && *p != '\0') {
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if (kstrtoul(p, 10, &v))
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pr_err("Failed to set tracing on: %s\n", p);
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if (v)
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tracer_tracing_on(tr);
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else
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tracer_tracing_off(tr);
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}
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p = xbc_node_find_value(node, "trace_clock", NULL);
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if (p && *p != '\0') {
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if (tracing_set_clock(tr, p) < 0)
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pr_err("Failed to set trace clock: %s\n", p);
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}
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p = xbc_node_find_value(node, "buffer_size", NULL);
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if (p && *p != '\0') {
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v = memparse(p, NULL);
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if (v < PAGE_SIZE)
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pr_err("Buffer size is too small: %s\n", p);
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if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
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pr_err("Failed to resize trace buffer to %s\n", p);
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}
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p = xbc_node_find_value(node, "cpumask", NULL);
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if (p && *p != '\0') {
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cpumask_var_t new_mask;
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if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
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if (cpumask_parse(p, new_mask) < 0 ||
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tracing_set_cpumask(tr, new_mask) < 0)
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pr_err("Failed to set new CPU mask %s\n", p);
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free_cpumask_var(new_mask);
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}
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}
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}
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#ifdef CONFIG_EVENT_TRACING
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static void __init
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trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *p;
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xbc_node_for_each_array_value(node, "events", anode, p) {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
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pr_err("String is too long: %s\n", p);
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continue;
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}
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if (ftrace_set_clr_event(tr, buf, 1) < 0)
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pr_err("Failed to enable event: %s\n", p);
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}
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}
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#ifdef CONFIG_KPROBE_EVENTS
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static int __init
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trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
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{
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struct dynevent_cmd cmd;
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *val;
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int ret = 0;
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xbc_node_for_each_array_value(node, "probes", anode, val) {
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kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
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ret = kprobe_event_gen_cmd_start(&cmd, event, val);
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if (ret) {
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pr_err("Failed to generate probe: %s\n", buf);
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break;
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}
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ret = kprobe_event_gen_cmd_end(&cmd);
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if (ret) {
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pr_err("Failed to add probe: %s\n", buf);
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break;
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}
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}
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return ret;
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}
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#else
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static inline int __init
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trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
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{
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pr_err("Kprobe event is not supported.\n");
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return -ENOTSUPP;
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}
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#endif
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#ifdef CONFIG_SYNTH_EVENTS
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static int __init
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trace_boot_add_synth_event(struct xbc_node *node, const char *event)
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{
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struct dynevent_cmd cmd;
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *p;
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int ret;
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synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
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ret = synth_event_gen_cmd_start(&cmd, event, NULL);
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if (ret)
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return ret;
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xbc_node_for_each_array_value(node, "fields", anode, p) {
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ret = synth_event_add_field_str(&cmd, p);
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if (ret)
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return ret;
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}
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ret = synth_event_gen_cmd_end(&cmd);
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if (ret < 0)
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pr_err("Failed to add synthetic event: %s\n", buf);
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return ret;
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}
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#else
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static inline int __init
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trace_boot_add_synth_event(struct xbc_node *node, const char *event)
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{
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pr_err("Synthetic event is not supported.\n");
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return -ENOTSUPP;
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}
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#endif
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static void __init
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trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
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struct xbc_node *enode)
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{
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struct trace_event_file *file;
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struct xbc_node *anode;
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char buf[MAX_BUF_LEN];
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const char *p, *group, *event;
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group = xbc_node_get_data(gnode);
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event = xbc_node_get_data(enode);
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if (!strcmp(group, "kprobes"))
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if (trace_boot_add_kprobe_event(enode, event) < 0)
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return;
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if (!strcmp(group, "synthetic"))
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if (trace_boot_add_synth_event(enode, event) < 0)
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return;
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mutex_lock(&event_mutex);
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file = find_event_file(tr, group, event);
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if (!file) {
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pr_err("Failed to find event: %s:%s\n", group, event);
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goto out;
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}
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p = xbc_node_find_value(enode, "filter", NULL);
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if (p && *p != '\0') {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
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pr_err("filter string is too long: %s\n", p);
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else if (apply_event_filter(file, buf) < 0)
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pr_err("Failed to apply filter: %s\n", buf);
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}
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if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
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xbc_node_for_each_array_value(enode, "actions", anode, p) {
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if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
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pr_err("action string is too long: %s\n", p);
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else if (trigger_process_regex(file, buf) < 0)
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pr_err("Failed to apply an action: %s\n", buf);
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}
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} else if (xbc_node_find_value(enode, "actions", NULL))
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pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
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if (xbc_node_find_value(enode, "enable", NULL)) {
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if (trace_event_enable_disable(file, 1, 0) < 0)
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pr_err("Failed to enable event node: %s:%s\n",
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group, event);
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}
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out:
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mutex_unlock(&event_mutex);
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}
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static void __init
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trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *gnode, *enode;
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node = xbc_node_find_child(node, "event");
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if (!node)
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return;
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/* per-event key starts with "event.GROUP.EVENT" */
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xbc_node_for_each_subkey(node, gnode)
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xbc_node_for_each_subkey(gnode, enode)
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trace_boot_init_one_event(tr, gnode, enode);
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}
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#else
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#define trace_boot_enable_events(tr, node) do {} while (0)
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#define trace_boot_init_events(tr, node) do {} while (0)
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#endif
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#ifdef CONFIG_DYNAMIC_FTRACE
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static void __init
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trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
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{
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struct xbc_node *anode;
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const char *p;
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char *q;
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xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
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q = kstrdup(p, GFP_KERNEL);
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if (!q)
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return;
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if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
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pr_err("Failed to add %s to ftrace filter\n", p);
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else
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ftrace_filter_param = true;
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kfree(q);
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}
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xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
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q = kstrdup(p, GFP_KERNEL);
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if (!q)
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return;
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if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
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pr_err("Failed to add %s to ftrace filter\n", p);
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else
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ftrace_filter_param = true;
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kfree(q);
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}
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}
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#else
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#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
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#endif
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static void __init
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trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
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{
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const char *p;
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trace_boot_set_ftrace_filter(tr, node);
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p = xbc_node_find_value(node, "tracer", NULL);
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if (p && *p != '\0') {
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if (tracing_set_tracer(tr, p) < 0)
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pr_err("Failed to set given tracer: %s\n", p);
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}
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/* Since tracer can free snapshot buffer, allocate snapshot here.*/
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if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
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if (tracing_alloc_snapshot_instance(tr) < 0)
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pr_err("Failed to allocate snapshot buffer\n");
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}
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}
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static void __init
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trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
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{
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trace_boot_set_instance_options(tr, node);
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trace_boot_init_events(tr, node);
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trace_boot_enable_events(tr, node);
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trace_boot_enable_tracer(tr, node);
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}
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static void __init
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trace_boot_init_instances(struct xbc_node *node)
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{
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struct xbc_node *inode;
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struct trace_array *tr;
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const char *p;
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node = xbc_node_find_child(node, "instance");
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if (!node)
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return;
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xbc_node_for_each_subkey(node, inode) {
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p = xbc_node_get_data(inode);
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if (!p || *p == '\0')
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continue;
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tr = trace_array_get_by_name(p);
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if (!tr) {
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pr_err("Failed to get trace instance %s\n", p);
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continue;
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}
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trace_boot_init_one_instance(tr, inode);
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trace_array_put(tr);
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}
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}
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static int __init trace_boot_init(void)
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{
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struct xbc_node *trace_node;
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struct trace_array *tr;
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trace_node = xbc_find_node("ftrace");
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if (!trace_node)
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return 0;
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tr = top_trace_array();
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if (!tr)
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return 0;
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/* Global trace array is also one instance */
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trace_boot_init_one_instance(tr, trace_node);
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trace_boot_init_instances(trace_node);
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disable_tracing_selftest("running boot-time tracing");
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return 0;
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}
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/*
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* Start tracing at the end of core-initcall, so that it starts tracing
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* from the beginning of postcore_initcall.
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*/
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core_initcall_sync(trace_boot_init);
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