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-rw-r--r--kernel/trace/trace_boot.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
new file mode 100644
index 0000000..d0a5e50
--- /dev/null
+++ b/kernel/trace/trace_boot.c
@@ -0,0 +1,126 @@
+/*
+ * 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 int trace_boot_enabled;
+
+
+/* Should be started after do_pre_smp_initcalls() in init/main.c */
+void start_boot_trace(void)
+{
+ trace_boot_enabled = 1;
+}
+
+void stop_boot_trace(void)
+{
+ trace_boot_enabled = 0;
+}
+
+void reset_boot_trace(struct trace_array *tr)
+{
+ stop_boot_trace();
+}
+
+static void boot_trace_init(struct trace_array *tr)
+{
+ int cpu;
+ boot_trace = tr;
+
+ trace_boot_enabled = 0;
+
+ for_each_cpu_mask(cpu, cpu_possible_map)
+ tracing_reset(tr, cpu);
+}
+
+static void boot_trace_ctrl_update(struct trace_array *tr)
+{
+ if (tr->ctrl)
+ start_boot_trace();
+ else
+ stop_boot_trace();
+}
+
+static enum print_line_t initcall_print_line(struct trace_iterator *iter)
+{
+ int ret;
+ struct trace_entry *entry = iter->ent;
+ struct trace_boot *field = (struct trace_boot *)entry;
+ struct boot_trace *it = &field->initcall;
+ struct trace_seq *s = &iter->seq;
+ struct timespec calltime = ktime_to_timespec(it->calltime);
+ struct timespec rettime = ktime_to_timespec(it->rettime);
+
+ if (entry->type == TRACE_BOOT) {
+ ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
+ calltime.tv_sec,
+ calltime.tv_nsec,
+ it->func, it->caller);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+
+ ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
+ "returned %d after %lld msecs\n",
+ rettime.tv_sec,
+ rettime.tv_nsec,
+ it->func, it->result, it->duration);
+
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ return TRACE_TYPE_HANDLED;
+ }
+ return TRACE_TYPE_UNHANDLED;
+}
+
+struct tracer boot_tracer __read_mostly =
+{
+ .name = "initcall",
+ .init = boot_trace_init,
+ .reset = reset_boot_trace,
+ .ctrl_update = boot_trace_ctrl_update,
+ .print_line = initcall_print_line,
+};
+
+void trace_boot(struct boot_trace *it, initcall_t fn)
+{
+ struct ring_buffer_event *event;
+ struct trace_boot *entry;
+ struct trace_array_cpu *data;
+ unsigned long irq_flags;
+ struct trace_array *tr = boot_trace;
+
+ if (!trace_boot_enabled)
+ return;
+
+ /* Get its name now since this function could
+ * disappear because it is in the .init section.
+ */
+ sprint_symbol(it->func, (unsigned long)fn);
+ preempt_disable();
+ data = tr->data[smp_processor_id()];
+
+ 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;
+ entry->initcall = *it;
+ ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+ trace_wake_up();
+
+ out:
+ preempt_enable();
+}