linux/samples/trace_printk/trace-printk.c
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   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 */
   7char *trace_printk_test_global_str =
   8        "This is a dynamic string that will use trace_puts\n";
   9
  10char *trace_printk_test_global_str_irq =
  11        "(irq) This is a dynamic string that will use trace_puts\n";
  12
  13char *trace_printk_test_global_str_fmt =
  14        "%sThis is a %s that will use trace_printk\n";
  15
  16static struct irq_work irqwork;
  17
  18static 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
  30static 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
  49static void __exit trace_printk_exit(void)
  50{
  51}
  52
  53module_init(trace_printk_init);
  54module_exit(trace_printk_exit);
  55
  56MODULE_AUTHOR("Steven Rostedt");
  57MODULE_DESCRIPTION("trace-printk");
  58MODULE_LICENSE("GPL");
  59