Merge tag 'pm-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These add support for new processors (Sierra Forest, Grand Ridge and
  Meteor Lake) to the intel_idle driver, make intel_pstate run on
  Emerald Rapids without HWP support and adjust it to utilize EPP values
  supplied by the platform firmware, fix issues, clean up code and
  improve documentation.

  The most significant fix addresses deadlocks in the core system-wide
  resume code that occur if async_schedule_dev() attempts to run its
  argument function synchronously (for example, due to a memory
  allocation failure). It rearranges the code in question which may
  increase the system resume time in some cases, but this basically is a
  removal of a premature optimization. That optimization will be added
  back later, but properly this time.

  Specifics:

   - Add support for the Sierra Forest, Grand Ridge and Meteorlake SoCs
     to the intel_idle cpuidle driver (Artem Bityutskiy, Zhang Rui)

   - Do not enable interrupts when entering idle in the haltpoll cpuidle
     driver (Borislav Petkov)

   - Add Emerald Rapids support in no-HWP mode to the intel_pstate
     cpufreq driver (Zhenguo Yao)

   - Use EPP values programmed by the platform firmware as balanced
     performance ones by default in intel_pstate (Srinivas Pandruvada)

   - Add a missing function return value check to the SCMI cpufreq
     driver to avoid unexpected behavior (Alexandra Diupina)

   - Fix parameter type warning in the armada-8k cpufreq driver (Gregory
     CLEMENT)

   - Rework trans_stat_show() in the devfreq core code to avoid buffer
     overflows (Christian Marangi)

   - Synchronize devfreq_monitor_[start/stop] so as to prevent a timer
     list corruption from occurring when devfreq governors are switched
     frequently (Mukesh Ojha)

   - Fix possible deadlocks in the core system-wide PM code that occur
     if device-handling functions cannot be executed asynchronously
     during resume from system-wide suspend (Rafael J. Wysocki)

   - Clean up unnecessary local variable initializations in multiple
     places in the hibernation code (Wang chaodong, Li zeming)

   - Adjust core hibernation code to avoid missing wakeup events that
     occur after saving an image to persistent storage (Chris Feng)

   - Update hibernation code to enforce correct ordering during image
     compression and decompression (Hongchen Zhang)

   - Use kmap_local_page() instead of kmap_atomic() in copy_data_page()
     during hibernation and restore (Chen Haonan)

   - Adjust documentation and code comments to reflect recent tasks
     freezer changes (Kevin Hao)

   - Repair excess function parameter description warning in the
     hibernation image-saving code (Randy Dunlap)

   - Fix _set_required_opps when opp is NULL (Bryan O'Donoghue)

   - Use device_get_match_data() in the OPP code for TI (Rob Herring)

   - Clean up OPP level and other parts and call dev_pm_opp_set_opp()
     recursively for required OPPs (Viresh Kumar)"

* tag 'pm-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (35 commits)
  OPP: Rename 'rate_clk_single'
  OPP: Pass rounded rate to _set_opp()
  OPP: Relocate dev_pm_opp_sync_regulators()
  PM: sleep: Fix possible deadlocks in core system-wide PM code
  OPP: Move dev_pm_opp_icc_bw to internal opp.h
  async: Introduce async_schedule_dev_nocall()
  async: Split async_schedule_node_domain()
  cpuidle: haltpoll: Do not enable interrupts when entering idle
  OPP: Fix _set_required_opps when opp is NULL
  OPP: The level field is always of unsigned int type
  PM: hibernate: Repair excess function parameter description warning
  PM: sleep: Remove obsolete comment from unlock_system_sleep()
  cpufreq: intel_pstate: Add Emerald Rapids support in no-HWP mode
  Documentation: PM: Adjust freezing-of-tasks.rst to the freezer changes
  PM: hibernate: Use kmap_local_page() in copy_data_page()
  intel_idle: add Sierra Forest SoC support
  intel_idle: add Grand Ridge SoC support
  PM / devfreq: Synchronize devfreq_monitor_[start/stop]
  cpufreq: armada-8k: Fix parameter type warning
  PM: hibernate: Enforce ordering during image compression/decompression
  ...

2 files changed, 51 insertions, 37 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index 5e6b74f30406..1e7e0bb4c14e 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -52,6 +52,9 @@ Description:
 
 			echo 0 > /sys/class/devfreq/.../trans_stat
 
+		If the transition table is bigger than PAGE_SIZE, reading
+		this will return an -EFBIG error.
+
 What:		/sys/class/devfreq/.../available_frequencies
 Date:		October 2012
 Contact:	Nishanth Menon <nm@ti.com>
diff --git a/Documentation/power/freezing-of-tasks.rst b/Documentation/power/freezing-of-tasks.rst
index 53b6a56c4635..df9755bfbd94 100644
--- a/Documentation/power/freezing-of-tasks.rst
+++ b/Documentation/power/freezing-of-tasks.rst
@@ -14,27 +14,28 @@ architectures).
 II. How does it work?
 =====================
 
-There are three per-task flags used for that, PF_NOFREEZE, PF_FROZEN
-and PF_FREEZER_SKIP (the last one is auxiliary).  The tasks that have
-PF_NOFREEZE unset (all user space processes and some kernel threads) are
-regarded as 'freezable' and treated in a special way before the system enters a
-suspend state as well as before a hibernation image is created (in what follows
-we only consider hibernation, but the description also applies to suspend).
+There is one per-task flag (PF_NOFREEZE) and three per-task states
+(TASK_FROZEN, TASK_FREEZABLE and __TASK_FREEZABLE_UNSAFE) used for that.
+The tasks that have PF_NOFREEZE unset (all user space tasks and some kernel
+threads) are regarded as 'freezable' and treated in a special way before the
+system enters a sleep state as well as before a hibernation image is created
+(hibernation is directly covered by what follows, but the description applies
+to system-wide suspend too).
 
 Namely, as the first step of the hibernation procedure the function
 freeze_processes() (defined in kernel/power/process.c) is called.  A system-wide
-variable system_freezing_cnt (as opposed to a per-task flag) is used to indicate
-whether the system is to undergo a freezing operation. And freeze_processes()
-sets this variable.  After this, it executes try_to_freeze_tasks() that sends a
-fake signal to all user space processes, and wakes up all the kernel threads.
-All freezable tasks must react to that by calling try_to_freeze(), which
-results in a call to __refrigerator() (defined in kernel/freezer.c), which sets
-the task's PF_FROZEN flag, changes its state to TASK_UNINTERRUPTIBLE and makes
-it loop until PF_FROZEN is cleared for it. Then, we say that the task is
-'frozen' and therefore the set of functions handling this mechanism is referred
-to as 'the freezer' (these functions are defined in kernel/power/process.c,
-kernel/freezer.c & include/linux/freezer.h). User space processes are generally
-frozen before kernel threads.
+static key freezer_active (as opposed to a per-task flag or state) is used to
+indicate whether the system is to undergo a freezing operation. And
+freeze_processes() sets this static key.  After this, it executes
+try_to_freeze_tasks() that sends a fake signal to all user space processes, and
+wakes up all the kernel threads. All freezable tasks must react to that by
+calling try_to_freeze(), which results in a call to __refrigerator() (defined
+in kernel/freezer.c), which changes the task's state to TASK_FROZEN, and makes
+it loop until it is woken by an explicit TASK_FROZEN wakeup. Then, that task
+is regarded as 'frozen' and so the set of functions handling this mechanism is
+referred to as 'the freezer' (these functions are defined in
+kernel/power/process.c, kernel/freezer.c & include/linux/freezer.h). User space
+tasks are generally frozen before kernel threads.
 
 __refrigerator() must not be called directly.  Instead, use the
 try_to_freeze() function (defined in include/linux/freezer.h), that checks
@@ -43,31 +44,40 @@ if the task is to be frozen and makes the task enter __refrigerator().
 For user space processes try_to_freeze() is called automatically from the
 signal-handling code, but the freezable kernel threads need to call it
 explicitly in suitable places or use the wait_event_freezable() or
-wait_event_freezable_timeout() macros (defined in include/linux/freezer.h)
-that combine interruptible sleep with checking if the task is to be frozen and
-calling try_to_freeze().  The main loop of a freezable kernel thread may look
+wait_event_freezable_timeout() macros (defined in include/linux/wait.h)
+that put the task to sleep (TASK_INTERRUPTIBLE) or freeze it (TASK_FROZEN) if
+freezer_active is set. The main loop of a freezable kernel thread may look
 like the following one::
 
 	set_freezable();
-	do {
-		hub_events();
-		wait_event_freezable(khubd_wait,
-				!list_empty(&hub_event_list) ||
-				kthread_should_stop());
-	} while (!kthread_should_stop() || !list_empty(&hub_event_list));
-
-(from drivers/usb/core/hub.c::hub_thread()).
-
-If a freezable kernel thread fails to call try_to_freeze() after the freezer has
-initiated a freezing operation, the freezing of tasks will fail and the entire
-hibernation operation will be cancelled.  For this reason, freezable kernel
-threads must call try_to_freeze() somewhere or use one of the
+
+	while (true) {
+		struct task_struct *tsk = NULL;
+
+		wait_event_freezable(oom_reaper_wait, oom_reaper_list != NULL);
+		spin_lock_irq(&oom_reaper_lock);
+		if (oom_reaper_list != NULL) {
+			tsk = oom_reaper_list;
+			oom_reaper_list = tsk->oom_reaper_list;
+		}
+		spin_unlock_irq(&oom_reaper_lock);
+
+		if (tsk)
+			oom_reap_task(tsk);
+	}
+
+(from mm/oom_kill.c::oom_reaper()).
+
+If a freezable kernel thread is not put to the frozen state after the freezer
+has initiated a freezing operation, the freezing of tasks will fail and the
+entire system-wide transition will be cancelled.  For this reason, freezable
+kernel threads must call try_to_freeze() somewhere or use one of the
 wait_event_freezable() and wait_event_freezable_timeout() macros.
 
 After the system memory state has been restored from a hibernation image and
 devices have been reinitialized, the function thaw_processes() is called in
-order to clear the PF_FROZEN flag for each frozen task.  Then, the tasks that
-have been frozen leave __refrigerator() and continue running.
+order to wake up each frozen task.  Then, the tasks that have been frozen leave
+__refrigerator() and continue running.
 
 
 Rationale behind the functions dealing with freezing and thawing of tasks
@@ -96,7 +106,8 @@ III. Which kernel threads are freezable?
 Kernel threads are not freezable by default.  However, a kernel thread may clear
 PF_NOFREEZE for itself by calling set_freezable() (the resetting of PF_NOFREEZE
 directly is not allowed).  From this point it is regarded as freezable
-and must call try_to_freeze() in a suitable place.
+and must call try_to_freeze() or variants of wait_event_freezable() in a
+suitable place.
 
 IV. Why do we do that?
 ======================