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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#define pr_fmt(fmt) "trace_boot: " fmt
#include <linux/bootconfig.h>#include <linux/cpumask.h>#include <linux/ftrace.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/mutex.h>#include <linux/string.h>#include <linux/slab.h>#include <linux/trace.h>#include <linux/trace_events.h>
#include "trace.h"
#define MAX_BUF_LEN 256
static void __inittrace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node){ struct xbc_node *anode; const char *p; char buf[MAX_BUF_LEN]; unsigned long v = 0;
/* Common ftrace options */ xbc_node_for_each_array_value(node, "options", anode, p) { if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) { pr_err("String is too long: %s\n", p); continue; }
if (trace_set_options(tr, buf) < 0) pr_err("Failed to set option: %s\n", buf); }
p = xbc_node_find_value(node, "tracing_on", NULL); if (p && *p != '\0') { if (kstrtoul(p, 10, &v)) pr_err("Failed to set tracing on: %s\n", p); if (v) tracer_tracing_on(tr); else tracer_tracing_off(tr); }
p = xbc_node_find_value(node, "trace_clock", NULL); if (p && *p != '\0') { if (tracing_set_clock(tr, p) < 0) pr_err("Failed to set trace clock: %s\n", p); }
p = xbc_node_find_value(node, "buffer_size", NULL); if (p && *p != '\0') { v = memparse(p, NULL); if (v < PAGE_SIZE) pr_err("Buffer size is too small: %s\n", p); if (trace_array_is_readonly(tr) || tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0) pr_err("Failed to resize trace buffer to %s\n", p); }
p = xbc_node_find_value(node, "cpumask", NULL); if (p && *p != '\0') { cpumask_var_t new_mask;
if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) { if (cpumask_parse(p, new_mask) < 0 || tracing_set_cpumask(tr, new_mask) < 0) pr_err("Failed to set new CPU mask %s\n", p); free_cpumask_var(new_mask); } }}
#ifdef CONFIG_EVENT_TRACINGstatic void __inittrace_boot_enable_events(struct trace_array *tr, struct xbc_node *node){ struct xbc_node *anode; char buf[MAX_BUF_LEN]; const char *p;
xbc_node_for_each_array_value(node, "events", anode, p) { if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) { pr_err("String is too long: %s\n", p); continue; }
if (ftrace_set_clr_event(tr, buf, 1) < 0) pr_err("Failed to enable event: %s\n", p); }}
#ifdef CONFIG_KPROBE_EVENTSstatic int __inittrace_boot_add_kprobe_event(struct xbc_node *node, const char *event){ struct dynevent_cmd cmd; struct xbc_node *anode; char buf[MAX_BUF_LEN]; const char *val; int ret = 0;
xbc_node_for_each_array_value(node, "probes", anode, val) { kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
ret = kprobe_event_gen_cmd_start(&cmd, event, val); if (ret) { pr_err("Failed to generate probe: %s\n", buf); break; }
ret = kprobe_event_gen_cmd_end(&cmd); if (ret) { pr_err("Failed to add probe: %s\n", buf); break; } }
return ret;}#elsestatic inline int __inittrace_boot_add_kprobe_event(struct xbc_node *node, const char *event){ pr_err("Kprobe event is not supported.\n"); return -ENOTSUPP;}#endif
#ifdef CONFIG_SYNTH_EVENTSstatic int __inittrace_boot_add_synth_event(struct xbc_node *node, const char *event){ struct dynevent_cmd cmd; struct xbc_node *anode; char buf[MAX_BUF_LEN]; const char *p; int ret;
synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);
ret = synth_event_gen_cmd_start(&cmd, event, NULL); if (ret) return ret;
xbc_node_for_each_array_value(node, "fields", anode, p) { ret = synth_event_add_field_str(&cmd, p); if (ret) return ret; }
ret = synth_event_gen_cmd_end(&cmd); if (ret < 0) pr_err("Failed to add synthetic event: %s\n", buf);
return ret;}#elsestatic inline int __inittrace_boot_add_synth_event(struct xbc_node *node, const char *event){ pr_err("Synthetic event is not supported.\n"); return -ENOTSUPP;}#endif
#ifdef CONFIG_HIST_TRIGGERSstatic int __init __printf(3, 4)append_printf(char **bufp, char *end, const char *fmt, ...){ va_list args; int ret;
if (*bufp == end) return -ENOSPC;
va_start(args, fmt); ret = vsnprintf(*bufp, end - *bufp, fmt, args); if (ret < end - *bufp) { *bufp += ret; } else { *bufp = end; ret = -ERANGE; } va_end(args);
return ret;}
static int __initappend_str_nospace(char **bufp, char *end, const char *str){ char *p = *bufp; int len;
while (p < end - 1 && *str != '\0') { if (!isspace(*str)) *(p++) = *str; str++; } *p = '\0'; if (p == end - 1) { *bufp = end; return -ENOSPC; } len = p - *bufp; *bufp = p; return (int)len;}
static int __inittrace_boot_hist_add_array(struct xbc_node *hnode, char **bufp, char *end, const char *key){ struct xbc_node *anode; const char *p; char sep;
p = xbc_node_find_value(hnode, key, &anode); if (p) { if (!anode) { pr_err("hist.%s requires value(s).\n", key); return -EINVAL; }
append_printf(bufp, end, ":%s", key); sep = '='; xbc_array_for_each_value(anode, p) { append_printf(bufp, end, "%c%s", sep, p); if (sep == '=') sep = ','; } } else return -ENOENT;
return 0;}
static int __inittrace_boot_hist_add_one_handler(struct xbc_node *hnode, char **bufp, char *end, const char *handler, const char *param){ struct xbc_node *knode, *anode; const char *p; char sep;
/* Compose 'handler' parameter */ p = xbc_node_find_value(hnode, param, NULL); if (!p) { pr_err("hist.%s requires '%s' option.\n", xbc_node_get_data(hnode), param); return -EINVAL; } append_printf(bufp, end, ":%s(%s)", handler, p);
/* Compose 'action' parameter */ knode = xbc_node_find_subkey(hnode, "trace"); if (!knode) knode = xbc_node_find_subkey(hnode, "save");
if (knode) { anode = xbc_node_get_child(knode); if (!anode || !xbc_node_is_value(anode)) { pr_err("hist.%s.%s requires value(s).\n", xbc_node_get_data(hnode), xbc_node_get_data(knode)); return -EINVAL; }
append_printf(bufp, end, ".%s", xbc_node_get_data(knode)); sep = '('; xbc_array_for_each_value(anode, p) { append_printf(bufp, end, "%c%s", sep, p); if (sep == '(') sep = ','; } append_printf(bufp, end, ")"); } else if (xbc_node_find_subkey(hnode, "snapshot")) { append_printf(bufp, end, ".snapshot()"); } else { pr_err("hist.%s requires an action.\n", xbc_node_get_data(hnode)); return -EINVAL; }
return 0;}
static int __inittrace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp, char *end, const char *param){ struct xbc_node *node; const char *p, *handler; int ret = 0;
handler = xbc_node_get_data(hnode);
xbc_node_for_each_subkey(hnode, node) { p = xbc_node_get_data(node); if (!isdigit(p[0])) continue; /* All digit started node should be instances. */ ret = trace_boot_hist_add_one_handler(node, bufp, end, handler, param); if (ret < 0) break; }
if (xbc_node_find_subkey(hnode, param)) ret = trace_boot_hist_add_one_handler(hnode, bufp, end, handler, param);
return ret;}
/* * Histogram boottime tracing syntax. * * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] { * keys = <KEY>[,...] * values = <VAL>[,...] * sort = <SORT-KEY>[,...] * size = <ENTRIES> * name = <HISTNAME> * var { <VAR> = <EXPR> ... } * pause|continue|clear * onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] } * onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] } * filter = <FILTER> * } * * Where <ACTION> are; * * trace = <EVENT>, <ARG1>[, ...] * save = <ARG1>[, ...] * snapshot */static int __inittrace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size){ struct xbc_node *node, *knode; char *end = buf + size; const char *p; int ret = 0;
append_printf(&buf, end, "hist");
ret = trace_boot_hist_add_array(hnode, &buf, end, "keys"); if (ret < 0) { if (ret == -ENOENT) pr_err("hist requires keys.\n"); return -EINVAL; }
ret = trace_boot_hist_add_array(hnode, &buf, end, "values"); if (ret == -EINVAL) return ret; ret = trace_boot_hist_add_array(hnode, &buf, end, "sort"); if (ret == -EINVAL) return ret;
p = xbc_node_find_value(hnode, "size", NULL); if (p) append_printf(&buf, end, ":size=%s", p);
p = xbc_node_find_value(hnode, "name", NULL); if (p) append_printf(&buf, end, ":name=%s", p);
node = xbc_node_find_subkey(hnode, "var"); if (node) { xbc_node_for_each_key_value(node, knode, p) { /* Expression must not include spaces. */ append_printf(&buf, end, ":%s=", xbc_node_get_data(knode)); append_str_nospace(&buf, end, p); } }
/* Histogram control attributes (mutual exclusive) */ if (xbc_node_find_value(hnode, "pause", NULL)) append_printf(&buf, end, ":pause"); else if (xbc_node_find_value(hnode, "continue", NULL)) append_printf(&buf, end, ":continue"); else if (xbc_node_find_value(hnode, "clear", NULL)) append_printf(&buf, end, ":clear");
/* Histogram handler and actions */ node = xbc_node_find_subkey(hnode, "onmax"); if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0) return -EINVAL; node = xbc_node_find_subkey(hnode, "onchange"); if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0) return -EINVAL; node = xbc_node_find_subkey(hnode, "onmatch"); if (node && trace_boot_hist_add_handlers(node, &buf, end, "event") < 0) return -EINVAL;
p = xbc_node_find_value(hnode, "filter", NULL); if (p) append_printf(&buf, end, " if %s", p);
if (buf == end) { pr_err("hist exceeds the max command length.\n"); return -E2BIG; }
return 0;}
static void __inittrace_boot_init_histograms(struct trace_event_file *file, struct xbc_node *hnode, char *buf, size_t size){ struct xbc_node *node; const char *p; char *tmp;
xbc_node_for_each_subkey(hnode, node) { p = xbc_node_get_data(node); if (!isdigit(p[0])) continue; /* All digit started node should be instances. */ if (trace_boot_compose_hist_cmd(node, buf, size) == 0) { tmp = kstrdup(buf, GFP_KERNEL); if (!tmp) return; if (trigger_process_regex(file, buf) < 0) pr_err("Failed to apply hist trigger: %s\n", tmp); kfree(tmp); } }
if (xbc_node_find_subkey(hnode, "keys")) { if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) { tmp = kstrdup(buf, GFP_KERNEL); if (!tmp) return; if (trigger_process_regex(file, buf) < 0) pr_err("Failed to apply hist trigger: %s\n", tmp); kfree(tmp); } }}#elsestatic void __inittrace_boot_init_histograms(struct trace_event_file *file, struct xbc_node *hnode, char *buf, size_t size){ /* do nothing */}#endif
static void __inittrace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode, struct xbc_node *enode){ struct trace_event_file *file; struct xbc_node *anode; char buf[MAX_BUF_LEN]; const char *p, *group, *event;
group = xbc_node_get_data(gnode); event = xbc_node_get_data(enode);
if (!strcmp(group, "kprobes")) if (trace_boot_add_kprobe_event(enode, event) < 0) return; if (!strcmp(group, "synthetic")) if (trace_boot_add_synth_event(enode, event) < 0) return;
mutex_lock(&event_mutex); file = find_event_file(tr, group, event); if (!file) { pr_err("Failed to find event: %s:%s\n", group, event); goto out; }
p = xbc_node_find_value(enode, "filter", NULL); if (p && *p != '\0') { if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) pr_err("filter string is too long: %s\n", p); else if (apply_event_filter(file, buf) < 0) pr_err("Failed to apply filter: %s\n", buf); }
if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) { xbc_node_for_each_array_value(enode, "actions", anode, p) { if (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) pr_err("action string is too long: %s\n", p); else if (trigger_process_regex(file, buf) < 0) pr_err("Failed to apply an action: %s\n", p); } anode = xbc_node_find_subkey(enode, "hist"); if (anode) trace_boot_init_histograms(file, anode, buf, ARRAY_SIZE(buf)); } else if (xbc_node_find_value(enode, "actions", NULL)) pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
if (xbc_node_find_value(enode, "enable", NULL)) { if (trace_event_enable_disable(file, 1, 0) < 0) pr_err("Failed to enable event node: %s:%s\n", group, event); }out: mutex_unlock(&event_mutex);}
static void __inittrace_boot_init_events(struct trace_array *tr, struct xbc_node *node){ struct xbc_node *gnode, *enode; bool enable, enable_all = false; const char *data;
node = xbc_node_find_subkey(node, "event"); if (!node) return; /* per-event key starts with "event.GROUP.EVENT" */ xbc_node_for_each_subkey(node, gnode) { data = xbc_node_get_data(gnode); if (!strcmp(data, "enable")) { enable_all = true; continue; } enable = false; xbc_node_for_each_subkey(gnode, enode) { data = xbc_node_get_data(enode); if (!strcmp(data, "enable")) { enable = true; continue; } trace_boot_init_one_event(tr, gnode, enode); } /* Event enablement must be done after event settings */ if (enable) { data = xbc_node_get_data(gnode); trace_array_set_clr_event(tr, data, NULL, true); } } /* Ditto */ if (enable_all) trace_array_set_clr_event(tr, NULL, NULL, true);}#else#define trace_boot_enable_events(tr, node) do {} while (0)#define trace_boot_init_events(tr, node) do {} while (0)#endif
#ifdef CONFIG_DYNAMIC_FTRACEstatic void __inittrace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node){ struct xbc_node *anode; const char *p; char *q;
xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) { q = kstrdup(p, GFP_KERNEL); if (!q) return; if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0) pr_err("Failed to add %s to ftrace filter\n", p); else ftrace_filter_param = true; kfree(q); } xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) { q = kstrdup(p, GFP_KERNEL); if (!q) return; if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0) pr_err("Failed to add %s to ftrace filter\n", p); else ftrace_filter_param = true; kfree(q); }}#else#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)#endif
static void __inittrace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node){ const char *p;
trace_boot_set_ftrace_filter(tr, node);
p = xbc_node_find_value(node, "tracer", NULL); if (p && *p != '\0') { if (trace_array_is_readonly(tr) || tracing_set_tracer(tr, p) < 0) pr_err("Failed to set given tracer: %s\n", p); }
/* Since tracer can free snapshot buffer, allocate snapshot here.*/ if (xbc_node_find_value(node, "alloc_snapshot", NULL)) { if (tracing_alloc_snapshot_instance(tr) < 0) pr_err("Failed to allocate snapshot buffer\n"); }}
static void __inittrace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node){ trace_boot_set_instance_options(tr, node); trace_boot_init_events(tr, node); trace_boot_enable_events(tr, node); trace_boot_enable_tracer(tr, node);}
static void __inittrace_boot_init_instances(struct xbc_node *node){ struct xbc_node *inode; struct trace_array *tr; const char *p;
node = xbc_node_find_subkey(node, "instance"); if (!node) return;
xbc_node_for_each_subkey(node, inode) { p = xbc_node_get_data(inode); if (!p || *p == '\0') continue;
tr = trace_array_get_by_name(p, NULL); if (!tr) { pr_err("Failed to get trace instance %s\n", p); continue; } trace_boot_init_one_instance(tr, inode); trace_array_put(tr); }}
static int __init trace_boot_init(void){ struct xbc_node *trace_node; struct trace_array *tr;
trace_node = xbc_find_node("ftrace"); if (!trace_node) return 0;
tr = top_trace_array(); if (!tr) return 0;
/* Global trace array is also one instance */ trace_boot_init_one_instance(tr, trace_node); trace_boot_init_instances(trace_node);
disable_tracing_selftest("running boot-time tracing");
return 0;}/* * Start tracing at the end of core-initcall, so that it starts tracing * from the beginning of postcore_initcall. */core_initcall_sync(trace_boot_init);