Hibernation: Check if ACPI is enabled during restore in the right place

The following scenario leads to total confusion of the platform firmware on
some boxes (eg. HPC nx6325):
* Hibernate with ACPI enabled
* Resume passing "acpi=off" to the boot kernel

To prevent this from happening it's necessary to check if ACPI is enabled (and
enable it if that's not the case) _right_ _after_ control has been transfered
from the boot kernel to the image kernel, before device_power_up() is called
(ie.  with interrupts disabled).   Enabling ACPI after calling
device_power_up() turns out to be insufficient.

For this reason, introduce new hibernation callback ->leave() that will be
executed before device_power_up() by the restored image kernel.   To make it
work, it also is necessary to move swsusp_suspend() from swsusp.c to disk.c
(it's name is changed to "create_image", which is more up to the point).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 74 insertions, 35 deletions

diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c
index acfb01b8ec82..048295ec3707 100644
--- a/drivers/acpi/sleep/main.c
+++ b/drivers/acpi/sleep/main.c
@@ -257,6 +257,15 @@ static int acpi_hibernation_enter(void)
         return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 }
 
+static void acpi_hibernation_leave(void)
+{
+        /*
+         * If ACPI is not enabled by the BIOS and the boot kernel, we need to
+         * enable it here.
+         */
+        acpi_enable();
+}
+
 static void acpi_hibernation_finish(void)
 {
         acpi_leave_sleep_state(ACPI_STATE_S4);
@@ -288,6 +297,7 @@ static struct platform_hibernation_ops acpi_hibernation_ops = {
         .finish = acpi_hibernation_finish,
         .prepare = acpi_hibernation_prepare,
         .enter = acpi_hibernation_enter,
+        .leave = acpi_hibernation_leave,
         .pre_restore = acpi_hibernation_pre_restore,
         .restore_cleanup = acpi_hibernation_restore_cleanup,
 };
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 9fd2b9acf7d9..4360e0816956 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -156,6 +156,12 @@ extern void mark_free_pages(struct zone *zone);
  *      Called after the nonboot CPUs have been disabled and all of the low
  *      level devices have been shut down (runs with IRQs off).
  *
+ * @leave: Perform the first stage of the cleanup after the system sleep state
+ *      indicated by @set_target() has been left.
+ *      Called right after the control has been passed from the boot kernel to
+ *      the image kernel, before the nonboot CPUs are enabled and before devices
+ *      are resumed.  Executed with interrupts disabled.
+ *
  * @pre_restore: Prepare system for the restoration from a hibernation image.
  *      Called right after devices have been frozen and before the nonboot
  *      CPUs are disabled (runs with IRQs on).
@@ -170,6 +176,7 @@ struct platform_hibernation_ops {
         void (*finish)(void);
         int (*prepare)(void);
         int (*enter)(void);
+        void (*leave)(void);
         int (*pre_restore)(void);
         void (*restore_cleanup)(void);
 };
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 555c0f0b2f7e..e50f4da18fd5 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -93,6 +93,17 @@ static int platform_pre_snapshot(int platform_mode)
 }
 
 /**
+ *      platform_leave - prepare the machine for switching to the normal mode
+ *      of operation using the platform driver (called with interrupts disabled)
+ */
+
+static void platform_leave(int platform_mode)
+{
+        if (platform_mode && hibernation_ops)
+                hibernation_ops->leave();
+}
+
+/**
  *      platform_finish - switch the machine to the normal mode of operation
  *      using the platform driver (must be called after platform_prepare())
  */
@@ -129,6 +140,51 @@ static void platform_restore_cleanup(int platform_mode)
 }
 
 /**
+ *      create_image - freeze devices that need to be frozen with interrupts
+ *      off, create the hibernation image and thaw those devices.  Control
+ *      reappears in this routine after a restore.
+ */
+
+int create_image(int platform_mode)
+{
+        int error;
+
+        error = arch_prepare_suspend();
+        if (error)
+                return error;
+
+        local_irq_disable();
+        /* At this point, device_suspend() has been called, but *not*
+         * device_power_down(). We *must* call device_power_down() now.
+         * Otherwise, drivers for some devices (e.g. interrupt controllers)
+         * become desynchronized with the actual state of the hardware
+         * at resume time, and evil weirdness ensues.
+         */
+        error = device_power_down(PMSG_FREEZE);
+        if (error) {
+                printk(KERN_ERR "Some devices failed to power down, "
+                        KERN_ERR "aborting suspend\n");
+                goto Enable_irqs;
+        }
+
+        save_processor_state();
+        error = swsusp_arch_suspend();
+        if (error)
+                printk(KERN_ERR "Error %d while creating the image\n", error);
+        /* Restore control flow magically appears here */
+        restore_processor_state();
+        if (!in_suspend)
+                platform_leave(platform_mode);
+        /* NOTE:  device_power_up() is just a resume() for devices
+         * that suspended with irqs off ... no overall powerup.
+         */
+        device_power_up();
+ Enable_irqs:
+        local_irq_enable();
+        return error;
+}
+
+/**
  *      hibernation_snapshot - quiesce devices and create the hibernation
  *      snapshot image.
  *      @platform_mode - if set, use the platform driver, if available, to
@@ -163,7 +219,7 @@ int hibernation_snapshot(int platform_mode)
         if (!error) {
                 if (hibernation_mode != HIBERNATION_TEST) {
                         in_suspend = 1;
-                        error = swsusp_suspend();
+                        error = create_image(platform_mode);
                         /* Control returns here after successful restore */
                 } else {
                         printk("swsusp debug: Waiting for 5 seconds.\n");
diff --git a/kernel/power/power.h b/kernel/power/power.h
index a0204dfc6c4c..195dc4611764 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -183,7 +183,6 @@ extern int swsusp_swap_in_use(void);
 extern int swsusp_check(void);
 extern int swsusp_shrink_memory(void);
 extern void swsusp_free(void);
-extern int swsusp_suspend(void);
 extern int swsusp_resume(void);
 extern int swsusp_read(unsigned int *flags_p);
 extern int swsusp_write(unsigned int flags);
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 5da304c8f1f6..e1722d3155f1 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -270,39 +270,6 @@ int swsusp_shrink_memory(void)
         return 0;
 }
 
-int swsusp_suspend(void)
-{
-        int error;
-
-        if ((error = arch_prepare_suspend()))
-                return error;
-
-        local_irq_disable();
-        /* At this point, device_suspend() has been called, but *not*
-         * device_power_down(). We *must* device_power_down() now.
-         * Otherwise, drivers for some devices (e.g. interrupt controllers)
-         * become desynchronized with the actual state of the hardware
-         * at resume time, and evil weirdness ensues.
-         */
-        if ((error = device_power_down(PMSG_FREEZE))) {
-                printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
-                goto Enable_irqs;
-        }
-
-        save_processor_state();
-        if ((error = swsusp_arch_suspend()))
-                printk(KERN_ERR "Error %d suspending\n", error);
-        /* Restore control flow magically appears here */
-        restore_processor_state();
-        /* NOTE:  device_power_up() is just a resume() for devices
-         * that suspended with irqs off ... no overall powerup.
-         */
-        device_power_up();
- Enable_irqs:
-        local_irq_enable();
-        return error;
-}
-
 int swsusp_resume(void)
 {
         int error;