samples/trace_printk/trace-printk.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 #include <linux/module.h>
0003 #include <linux/kthread.h>
0004 #include <linux/irq_work.h>
0005
0006 /* Must not be static to force gcc to consider these non constant */
0007 char *trace_printk_test_global_str =
0008     "This is a dynamic string that will use trace_puts\n";
0009
0010 char *trace_printk_test_global_str_irq =
0011     "(irq) This is a dynamic string that will use trace_puts\n";
0012
0013 char *trace_printk_test_global_str_fmt =
0014     "%sThis is a %s that will use trace_printk\n";
0015
0016 static struct irq_work irqwork;
0017
0018 static void trace_printk_irq_work(struct irq_work *work)
0019 {
0020     trace_printk("(irq) This is a static string that will use trace_bputs\n");
0021     trace_printk(trace_printk_test_global_str_irq);
0022
0023     trace_printk("(irq) This is a %s that will use trace_bprintk()\n",
0024              "static string");
0025
0026     trace_printk(trace_printk_test_global_str_fmt,
0027              "(irq) ", "dynamic string");
0028 }
0029
0030 static int __init trace_printk_init(void)
0031 {
0032     init_irq_work(&irqwork, trace_printk_irq_work);
0033
0034     trace_printk("This is a static string that will use trace_bputs\n");
0035     trace_printk(trace_printk_test_global_str);
0036
0037     /* Kick off printing in irq context */
0038     irq_work_queue(&irqwork);
0039     irq_work_sync(&irqwork);
0040
0041     trace_printk("This is a %s that will use trace_bprintk()\n",
0042              "static string");
0043
0044     trace_printk(trace_printk_test_global_str_fmt, "", "dynamic string");
0045
0046     return 0;
0047 }
0048
0049 static void __exit trace_printk_exit(void)
0050 {
0051 }
0052
0053 module_init(trace_printk_init);
0054 module_exit(trace_printk_exit);
0055
0056 MODULE_AUTHOR("Steven Rostedt");
0057 MODULE_DESCRIPTION("trace-printk");
0058 MODULE_LICENSE("GPL");