Hibernation: New testing facility (rev. 2)

Make it possible to test the hibernation core code with the help of the
/sys/power/pm_test attribute introduced for suspend testing in the previous
patch.

Writing an appropriate string to this file causes the hibernation code to work
in one of the test modes defined as follows:

freezer
- test the freezing of processes

devices
- test the freezing of processes and suspending of devices

platform
- test the freezing of processes, suspending of devices and platform global
  control methods(*)

processors
- test the freezing of processes, suspending of devices, platform global
  control methods(*) and the disabling of nonboot CPUs

core
- test the freezing of processes, suspending of devices, platform global
  control methods(*), the disabling of nonboot CPUs and suspending of
  platform/system devices

(*) - the platform global control methods are only available on ACPI systems
      and are only tested if the hibernation mode is set to "platform"

Then, if a hibernation is started by normal means, the hibernation core will
perform its normal operations up to the point indicated by given test level.
Next, it will wait for 5 seconds and carry out the resume operations needed to
transition the system back to the fully functional state.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 6597365..0866b16 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -70,6 +70,35 @@
 	mutex_unlock(&pm_mutex);
 }
 
+#ifdef CONFIG_PM_DEBUG
+static void hibernation_debug_sleep(void)
+{
+	printk(KERN_INFO "hibernation debug: Waiting for 5 seconds.\n");
+	mdelay(5000);
+}
+
+static int hibernation_testmode(int mode)
+{
+	if (hibernation_mode == mode) {
+		hibernation_debug_sleep();
+		return 1;
+	}
+	return 0;
+}
+
+static int hibernation_test(int level)
+{
+	if (pm_test_level == level) {
+		hibernation_debug_sleep();
+		return 1;
+	}
+	return 0;
+}
+#else /* !CONFIG_PM_DEBUG */
+static int hibernation_testmode(int mode) { return 0; }
+static int hibernation_test(int level) { return 0; }
+#endif /* !CONFIG_PM_DEBUG */
+
 /**
  *	platform_start - tell the platform driver that we're starting
  *	hibernation
@@ -167,6 +196,10 @@
 		goto Enable_irqs;
 	}
 
+	if (hibernation_test(TEST_CORE))
+		goto Power_up;
+
+	in_suspend = 1;
 	save_processor_state();
 	error = swsusp_arch_suspend();
 	if (error)
@@ -175,6 +208,7 @@
 	restore_processor_state();
 	if (!in_suspend)
 		platform_leave(platform_mode);
+ Power_up:
 	/* NOTE:  device_power_up() is just a resume() for devices
 	 * that suspended with irqs off ... no overall powerup.
 	 */
@@ -211,24 +245,29 @@
 	if (error)
 		goto Resume_console;
 
-	error = platform_pre_snapshot(platform_mode);
-	if (error)
+	if (hibernation_test(TEST_DEVICES))
 		goto Resume_devices;
 
+	error = platform_pre_snapshot(platform_mode);
+	if (error || hibernation_test(TEST_PLATFORM))
+		goto Finish;
+
 	error = disable_nonboot_cpus();
 	if (!error) {
-		if (hibernation_mode != HIBERNATION_TEST) {
-			in_suspend = 1;
-			error = create_image(platform_mode);
-			/* Control returns here after successful restore */
-		} else {
-			printk("swsusp debug: Waiting for 5 seconds.\n");
-			mdelay(5000);
-		}
+		if (hibernation_test(TEST_CPUS))
+			goto Enable_cpus;
+
+		if (hibernation_testmode(HIBERNATION_TEST))
+			goto Enable_cpus;
+
+		error = create_image(platform_mode);
+		/* Control returns here after successful restore */
 	}
+ Enable_cpus:
 	enable_nonboot_cpus();
- Resume_devices:
+ Finish:
 	platform_finish(platform_mode);
+ Resume_devices:
 	device_resume();
  Resume_console:
 	resume_console();
@@ -406,11 +445,12 @@
 	if (error)
 		goto Finish;
 
-	if (hibernation_mode == HIBERNATION_TESTPROC) {
-		printk("swsusp debug: Waiting for 5 seconds.\n");
-		mdelay(5000);
+	if (hibernation_test(TEST_FREEZER))
 		goto Thaw;
-	}
+
+	if (hibernation_testmode(HIBERNATION_TESTPROC))
+		goto Thaw;
+
 	error = hibernation_snapshot(hibernation_mode == HIBERNATION_PLATFORM);
 	if (in_suspend && !error) {
 		unsigned int flags = 0;