aboutsummaryrefslogtreecommitdiff
path: root/samples/trace_printk
diff options
context:
space:
mode:
authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2016-06-17 14:50:23 -0400
committerSteven Rostedt <rostedt@goodmis.org>2016-06-20 09:54:21 -0400
commitaad108aa9d1aca5be178ef40325dcc99b448e866 (patch)
tree0f86ba6921d86ac462dc3db3e484a1a08de70e0f /samples/trace_printk
parente2ace001176dc9745a472fe8bda1f0b28a4d7351 (diff)
downloadlinux-stericsson-aad108aa9d1aca5be178ef40325dcc99b448e866.tar.gz
tracing: Add trace_printk sample code
Add sample code to test trace_printk(). The trace_printk() functions should never be used in production code. This makes testing it a bit more difficult. Having a sample module that can test use cases of trace_printk() can help out. Currently it just tests trace_printk() where it will be converted into: trace_bputs() trace_puts() trace_bprintk() as well as staying as the normal _trace_printk(). It also tests its use in interrupt context as that will test the auxilery buffers. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'samples/trace_printk')
-rw-r--r--samples/trace_printk/Makefile6
-rw-r--r--samples/trace_printk/trace-printk.c56
2 files changed, 62 insertions, 0 deletions
diff --git a/samples/trace_printk/Makefile b/samples/trace_printk/Makefile
new file mode 100644
index 000000000000..19900ab2b00d
--- /dev/null
+++ b/samples/trace_printk/Makefile
@@ -0,0 +1,6 @@
+# builds a module that calls various trace_printk routines
+# then to use one (as root): insmod <module_name.ko>
+
+# This module can also be used to test the trace_printk code.
+
+obj-$(CONFIG_SAMPLE_TRACE_PRINTK) += trace-printk.o
diff --git a/samples/trace_printk/trace-printk.c b/samples/trace_printk/trace-printk.c
new file mode 100644
index 000000000000..e9e0040ff7be
--- /dev/null
+++ b/samples/trace_printk/trace-printk.c
@@ -0,0 +1,56 @@
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/irq_work.h>
+
+/* Must not be static to force gcc to consider these non constant */
+char *trace_printk_test_global_str =
+ "This is a dynamic string that will use trace_puts\n";
+
+char *trace_printk_test_global_str_irq =
+ "(irq) This is a dynamic string that will use trace_puts\n";
+
+char *trace_printk_test_global_str_fmt =
+ "%sThis is a %s that will use trace_printk\n";
+
+static struct irq_work irqwork;
+
+static void trace_printk_irq_work(struct irq_work *work)
+{
+ trace_printk("(irq) This is a static string that will use trace_bputs\n");
+ trace_printk(trace_printk_test_global_str_irq);
+
+ trace_printk("(irq) This is a %s that will use trace_bprintk()\n",
+ "static string");
+
+ trace_printk(trace_printk_test_global_str_fmt,
+ "(irq) ", "dynamic string");
+}
+
+static int __init trace_printk_init(void)
+{
+ init_irq_work(&irqwork, trace_printk_irq_work);
+
+ trace_printk("This is a static string that will use trace_bputs\n");
+ trace_printk(trace_printk_test_global_str);
+
+ /* Kick off printing in irq context */
+ irq_work_queue(&irqwork);
+
+ trace_printk("This is a %s that will use trace_bprintk()\n",
+ "static string");
+
+ trace_printk(trace_printk_test_global_str_fmt, "", "dynamic string");
+
+ return 0;
+}
+
+static void __exit trace_printk_exit(void)
+{
+}
+
+module_init(trace_printk_init);
+module_exit(trace_printk_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("trace-printk");
+MODULE_LICENSE("GPL");