Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / kernel / trace / trace_nop.c

diff --git a/kernel/kernel/trace/trace_nop.c b/kernel/kernel/trace/trace_nop.c
new file mode 100644 (file)
index 0000000..8bb2071
--- /dev/null
+++ b/kernel/kernel/trace/trace_nop.c
@@ -0,0 +1,99 @@
+/*
+ * nop tracer
+ *
+ * Copyright (C) 2008 Steven Noonan <steven@uplinklabs.net>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+/* Our two options */
+enum {
+       TRACE_NOP_OPT_ACCEPT = 0x1,
+       TRACE_NOP_OPT_REFUSE = 0x2
+};
+
+/* Options for the tracer (see trace_options file) */
+static struct tracer_opt nop_opts[] = {
+       /* Option that will be accepted by set_flag callback */
+       { TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) },
+       /* Option that will be refused by set_flag callback */
+       { TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) },
+       { } /* Always set a last empty entry */
+};
+
+static struct tracer_flags nop_flags = {
+       /* You can check your flags value here when you want. */
+       .val = 0, /* By default: all flags disabled */
+       .opts = nop_opts
+};
+
+static struct trace_array      *ctx_trace;
+
+static void start_nop_trace(struct trace_array *tr)
+{
+       /* Nothing to do! */
+}
+
+static void stop_nop_trace(struct trace_array *tr)
+{
+       /* Nothing to do! */
+}
+
+static int nop_trace_init(struct trace_array *tr)
+{
+       ctx_trace = tr;
+       start_nop_trace(tr);
+       return 0;
+}
+
+static void nop_trace_reset(struct trace_array *tr)
+{
+       stop_nop_trace(tr);
+}
+
+/* It only serves as a signal handler and a callback to
+ * accept or refuse tthe setting of a flag.
+ * If you don't implement it, then the flag setting will be
+ * automatically accepted.
+ */
+static int nop_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+       /*
+        * Note that you don't need to update nop_flags.val yourself.
+        * The tracing Api will do it automatically if you return 0
+        */
+       if (bit == TRACE_NOP_OPT_ACCEPT) {
+               printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept."
+                       " Now cat trace_options to see the result\n",
+                       set);
+               return 0;
+       }
+
+       if (bit == TRACE_NOP_OPT_REFUSE) {
+               printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse."
+                       "Now cat trace_options to see the result\n",
+                       set);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+
+struct tracer nop_trace __read_mostly =
+{
+       .name           = "nop",
+       .init           = nop_trace_init,
+       .reset          = nop_trace_reset,
+#ifdef CONFIG_FTRACE_SELFTEST
+       .selftest       = trace_selftest_startup_nop,
+#endif
+       .flags          = &nop_flags,
+       .set_flag       = nop_set_flag,
+       .allow_instances = true,
+};
+