ftrace: fix boot trace sched startup

[firefly-linux-kernel-4.4.55.git] / kernel / trace / trace_boot.c

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 7c15f3e68ba35e25c114e4ed09e017bc27c81d31..662cb9198906e2684b05742327355ff56fda3268 100644 (file)
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -8,22 +8,43 @@
 #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;
+static bool pre_initcalls_finished;
 
-
-/* Should be started after do_pre_smp_initcalls() in init/main.c */
+/* 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)
 {
-       trace_boot_enabled = 1;
+       pre_initcalls_finished = true;
+}
+
+void enable_boot_trace(void)
+{
+       if (pre_initcalls_finished)
+               tracing_start_cmdline_record();
 }
 
-void stop_boot_trace(struct trace_array *tr)
+void disable_boot_trace(void)
 {
-       trace_boot_enabled = 0;
+       if (pre_initcalls_finished)
+               tracing_stop_cmdline_record();
+}
+
+static void reset_boot_trace(struct trace_array *tr)
+{
+       int cpu;
+
+       tr->time_start = ftrace_now(tr->cpu);
+
+       for_each_online_cpu(cpu)
+               tracing_reset(tr, cpu);
 }
 
 static void boot_trace_init(struct trace_array *tr)
@@ -31,18 +52,18 @@ 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);
+
+       tracing_cmdline_assign_trace(tr);
 }
 
 static void boot_trace_ctrl_update(struct trace_array *tr)
 {
        if (tr->ctrl)
-               start_boot_trace();
+               enable_boot_trace();
        else
-               stop_boot_trace(tr);
+               disable_boot_trace();
 }
 
 static enum print_line_t initcall_print_line(struct trace_iterator *iter)
@@ -56,17 +77,19 @@ static enum print_line_t initcall_print_line(struct trace_iterator *iter)
        struct timespec rettime = ktime_to_timespec(it->rettime);
 
        if (entry->type == TRACE_BOOT) {
-               ret = trace_seq_printf(s, "[%5ld.%06ld] calling  %pF @ %i\n",
+               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.%06ld] initcall %pF "
+
+               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;
@@ -78,13 +101,12 @@ struct tracer boot_tracer __read_mostly =
 {
        .name           = "initcall",
        .init           = boot_trace_init,
-       .reset          = stop_boot_trace,
+       .reset          = reset_boot_trace,
        .ctrl_update    = boot_trace_ctrl_update,
        .print_line     = initcall_print_line,
 };
 
-
-void trace_boot(struct boot_trace *it)
+void trace_boot(struct boot_trace *it, initcall_t fn)
 {
        struct ring_buffer_event *event;
        struct trace_boot *entry;
@@ -92,9 +114,13 @@ void trace_boot(struct boot_trace *it)
        unsigned long irq_flags;
        struct trace_array *tr = boot_trace;
 
-       if (!trace_boot_enabled)
+       if (!pre_initcalls_finished)
                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()];