// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Simple stack backtrace regression test module
   *
   * (C) Copyright 2008 Intel Corporation
   * Author: Arjan van de Ven <arjan@linux.intel.com>

   */

  #include <linux/completion.h>

  #include <linux/delay.h>

  #include <linux/interrupt.h>

  #include <linux/module.h>
  #include <linux/sched.h>

  #include <linux/stacktrace.h>

  static void backtrace_test_normal(void)
  {

  	pr_info("Testing a backtrace from process context.
  ");
  	pr_info("The following trace is a kernel self test and not a bug!
  ");

  
  	dump_stack();
  }
  
  static DECLARE_COMPLETION(backtrace_work);
  
  static void backtrace_test_irq_callback(unsigned long data)
  {
  	dump_stack();
  	complete(&backtrace_work);
  }
  
  static DECLARE_TASKLET(backtrace_tasklet, &backtrace_test_irq_callback, 0);

  static void backtrace_test_irq(void)

  {

  	pr_info("Testing a backtrace from irq context.
  ");
  	pr_info("The following trace is a kernel self test and not a bug!
  ");

  
  	init_completion(&backtrace_work);
  	tasklet_schedule(&backtrace_tasklet);
  	wait_for_completion(&backtrace_work);

  }

  
  #ifdef CONFIG_STACKTRACE
  static void backtrace_test_saved(void)
  {

  	unsigned long entries[8];

  	unsigned int nr_entries;

  	pr_info("Testing a saved backtrace.
  ");
  	pr_info("The following trace is a kernel self test and not a bug!
  ");

  	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
  	stack_trace_print(entries, nr_entries, 0);

  }
  #else
  static void backtrace_test_saved(void)
  {

  	pr_info("Saved backtrace test skipped.
  ");

  }
  #endif

  static int backtrace_regression_test(void)
  {

  	pr_info("====[ backtrace testing ]===========
  ");

  	backtrace_test_normal();
  	backtrace_test_irq();

  	backtrace_test_saved();

  	pr_info("====[ end of backtrace testing ]====
  ");

  	return 0;
  }
  
  static void exitf(void)
  {
  }
  
  module_init(backtrace_regression_test);
  module_exit(exitf);
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");