samples/trace_printk/trace-printk.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/module.h>
   3 #include <linux/kthread.h>
   4 #include <linux/irq_work.h>
   5
   6 /* Must not be static to force gcc to consider these non constant */
   7 char *trace_printk_test_global_str =
   8         "This is a dynamic string that will use trace_puts\n";
   9
  10 char *trace_printk_test_global_str_irq =
  11         "(irq) This is a dynamic string that will use trace_puts\n";
  12
  13 char *trace_printk_test_global_str_fmt =
  14         "%sThis is a %s that will use trace_printk\n";
  15
  16 static struct irq_work irqwork;
  17
  18 static void trace_printk_irq_work(struct irq_work *work)
  19 {
  20         trace_printk("(irq) This is a static string that will use trace_bputs\n");
  21         trace_printk(trace_printk_test_global_str_irq);
  22
  23         trace_printk("(irq) This is a %s that will use trace_bprintk()\n",
  24                      "static string");
  25
  26         trace_printk(trace_printk_test_global_str_fmt,
  27                      "(irq) ", "dynamic string");
  28 }
  29
  30 static int __init trace_printk_init(void)
  31 {
  32         init_irq_work(&irqwork, trace_printk_irq_work);
  33
  34         trace_printk("This is a static string that will use trace_bputs\n");
  35         trace_printk(trace_printk_test_global_str);
  36
  37         /* Kick off printing in irq context */
  38         irq_work_queue(&irqwork);
  39         irq_work_sync(&irqwork);
  40
  41         trace_printk("This is a %s that will use trace_bprintk()\n",
  42                      "static string");
  43
  44         trace_printk(trace_printk_test_global_str_fmt, "", "dynamic string");
  45
  46         return 0;
  47 }
  48
  49 static void __exit trace_printk_exit(void)
  50 {
  51 }
  52
  53 module_init(trace_printk_init);
  54 module_exit(trace_printk_exit);
  55
  56 MODULE_AUTHOR("Steven Rostedt");
  57 MODULE_DESCRIPTION("trace-printk");
  58 MODULE_LICENSE("GPL");