Linux Kernel Markers - Samples

[linux-2.6-omap-h63xx.git] / samples / markers / probe-example.c

diff --git a/samples/markers/probe-example.c b/samples/markers/probe-example.c
new file mode 100644 (file)
index 0000000..238b2e3
--- /dev/null
+++ b/samples/markers/probe-example.c
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+/* probe-example.c
+ *
+ * Connects two functions to marker call sites.
+ *
+ * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/marker.h>
+#include <asm/atomic.h>
+
+struct probe_data {
+       const char *name;
+       const char *format;
+       marker_probe_func *probe_func;
+};
+
+void probe_subsystem_event(const struct marker *mdata, void *private,
+       const char *format, ...)
+{
+       va_list ap;
+       /* Declare args */
+       unsigned int value;
+       const char *mystr;
+
+       /* Assign args */
+       va_start(ap, format);
+       value = va_arg(ap, typeof(value));
+       mystr = va_arg(ap, typeof(mystr));
+
+       /* Call printk */
+       printk(KERN_DEBUG "Value %u, string %s\n", value, mystr);
+
+       /* or count, check rights, serialize data in a buffer */
+
+       va_end(ap);
+}
+
+atomic_t eventb_count = ATOMIC_INIT(0);
+
+void probe_subsystem_eventb(const struct marker *mdata, void *private,
+       const char *format, ...)
+{
+       /* Increment counter */
+       atomic_inc(&eventb_count);
+}
+
+static struct probe_data probe_array[] =
+{
+       {       .name = "subsystem_event",
+               .format = "%d %s",
+               .probe_func = probe_subsystem_event },
+       {       .name = "subsystem_eventb",
+               .format = MARK_NOARGS,
+               .probe_func = probe_subsystem_eventb },
+};
+
+static int __init probe_init(void)
+{
+       int result;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
+               result = marker_probe_register(probe_array[i].name,
+                               probe_array[i].format,
+                               probe_array[i].probe_func, &probe_array[i]);
+               if (result)
+                       printk(KERN_INFO "Unable to register probe %s\n",
+                               probe_array[i].name);
+               result = marker_arm(probe_array[i].name);
+               if (result)
+                       printk(KERN_INFO "Unable to arm probe %s\n",
+                               probe_array[i].name);
+       }
+       return 0;
+}
+
+static void __exit probe_fini(void)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(probe_array); i++)
+               marker_probe_unregister(probe_array[i].name);
+       printk(KERN_INFO "Number of event b : %u\n",
+                       atomic_read(&eventb_count));
+}
+
+module_init(probe_init);
+module_exit(probe_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("SUBSYSTEM Probe");