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-rw-r--r--kernel/trace/trace_boot.c186
1 files changed, 186 insertions, 0 deletions
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
new file mode 100644
index 00000000000..3ccebde2848
--- /dev/null
+++ b/kernel/trace/trace_boot.c
@@ -0,0 +1,186 @@
+/*
+ * ring buffer based initcalls tracer
+ *
+ * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/ftrace.h>
+#include <linux/kallsyms.h>
+
+#include "trace.h"
+
+static struct trace_array *boot_trace;
+static bool pre_initcalls_finished;
+
+/* Tells the boot tracer that the pre_smp_initcalls are finished.
+ * So we are ready .
+ * It doesn't enable sched events tracing however.
+ * You have to call enable_boot_trace to do so.
+ */
+void start_boot_trace(void)
+{
+ pre_initcalls_finished = true;
+}
+
+void enable_boot_trace(void)
+{
+ if (pre_initcalls_finished)
+ tracing_start_sched_switch_record();
+}
+
+void disable_boot_trace(void)
+{
+ if (pre_initcalls_finished)
+ tracing_stop_sched_switch_record();
+}
+
+static int boot_trace_init(struct trace_array *tr)
+{
+ int cpu;
+ boot_trace = tr;
+
+ for_each_cpu_mask(cpu, cpu_possible_map)
+ tracing_reset(tr, cpu);
+
+ tracing_sched_switch_assign_trace(tr);
+ return 0;
+}
+
+static enum print_line_t
+initcall_call_print_line(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+ struct trace_seq *s = &iter->seq;
+ struct trace_boot_call *field;
+ struct boot_trace_call *call;
+ u64 ts;
+ unsigned long nsec_rem;
+ int ret;
+
+ trace_assign_type(field, entry);
+ call = &field->boot_call;
+ ts = iter->ts;
+ nsec_rem = do_div(ts, 1000000000);
+
+ ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
+ (unsigned long)ts, nsec_rem, call->func, call->caller);
+
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ else
+ return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t
+initcall_ret_print_line(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+ struct trace_seq *s = &iter->seq;
+ struct trace_boot_ret *field;
+ struct boot_trace_ret *init_ret;
+ u64 ts;
+ unsigned long nsec_rem;
+ int ret;
+
+ trace_assign_type(field, entry);
+ init_ret = &field->boot_ret;
+ ts = iter->ts;
+ nsec_rem = do_div(ts, 1000000000);
+
+ ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
+ "returned %d after %llu msecs\n",
+ (unsigned long) ts,
+ nsec_rem,
+ init_ret->func, init_ret->result, init_ret->duration);
+
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ else
+ return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t initcall_print_line(struct trace_iterator *iter)
+{
+ struct trace_entry *entry = iter->ent;
+
+ switch (entry->type) {
+ case TRACE_BOOT_CALL:
+ return initcall_call_print_line(iter);
+ case TRACE_BOOT_RET:
+ return initcall_ret_print_line(iter);
+ default:
+ return TRACE_TYPE_UNHANDLED;
+ }
+}
+
+struct tracer boot_tracer __read_mostly =
+{
+ .name = "initcall",
+ .init = boot_trace_init,
+ .reset = tracing_reset_online_cpus,
+ .print_line = initcall_print_line,
+};
+
+void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
+{
+ struct ring_buffer_event *event;
+ struct trace_boot_call *entry;
+ unsigned long irq_flags;
+ struct trace_array *tr = boot_trace;
+
+ if (!pre_initcalls_finished)
+ return;
+
+ /* Get its name now since this function could
+ * disappear because it is in the .init section.
+ */
+ sprint_symbol(bt->func, (unsigned long)fn);
+ preempt_disable();
+
+ event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+ &irq_flags);
+ if (!event)
+ goto out;
+ entry = ring_buffer_event_data(event);
+ tracing_generic_entry_update(&entry->ent, 0, 0);
+ entry->ent.type = TRACE_BOOT_CALL;
+ entry->boot_call = *bt;
+ ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+ trace_wake_up();
+
+ out:
+ preempt_enable();
+}
+
+void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
+{
+ struct ring_buffer_event *event;
+ struct trace_boot_ret *entry;
+ unsigned long irq_flags;
+ struct trace_array *tr = boot_trace;
+
+ if (!pre_initcalls_finished)
+ return;
+
+ sprint_symbol(bt->func, (unsigned long)fn);
+ preempt_disable();
+
+ event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+ &irq_flags);
+ if (!event)
+ goto out;
+ entry = ring_buffer_event_data(event);
+ tracing_generic_entry_update(&entry->ent, 0, 0);
+ entry->ent.type = TRACE_BOOT_RET;
+ entry->boot_ret = *bt;
+ ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+ trace_wake_up();
+
+ out:
+ preempt_enable();
+}