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 00000000000..d0a5e50eeff
--- /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();
+}