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2019-05-15Merge tag 'pm-5.2-rc1-2' of ↵Linus Torvalds1-60/+80
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more power management updates from Rafael Wysocki: "These fix a recent regression causing kernels built with CONFIG_PM unset to crash on systems that support the Performance and Energy Bias Hint (EPB), clean up the cpufreq core and some users of transition notifiers and introduce a new power domain flag into the generic power domains framework (genpd). Specifics: - Fix recent regression causing kernels built with CONFIG_PM unset to crash on systems that support the Performance and Energy Bias Hint (EPB) by avoiding to compile the EPB-related code depending on CONFIG_PM when it is unset (Rafael Wysocki). - Clean up the transition notifier invocation code in the cpufreq core and change some users of cpufreq transition notifiers accordingly (Viresh Kumar). - Change MAINTAINERS to cover the schedutil governor as part of cpufreq (Viresh Kumar). - Simplify cpufreq_init_policy() to avoid redundant computations (Yue Hu). - Add explanatory comment to the cpufreq core (Rafael Wysocki). - Introduce a new flag, GENPD_FLAG_RPM_ALWAYS_ON, to the generic power domains (genpd) framework along with the first user of it (Leonard Crestez)" * tag 'pm-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: soc: imx: gpc: Use GENPD_FLAG_RPM_ALWAYS_ON for ERR009619 PM / Domains: Add GENPD_FLAG_RPM_ALWAYS_ON flag cpufreq: Update MAINTAINERS to include schedutil governor cpufreq: Don't find governor for setpolicy drivers in cpufreq_init_policy() cpufreq: Explain the kobject_put() in cpufreq_policy_alloc() cpufreq: Call transition notifier only once for each policy x86: intel_epb: Take CONFIG_PM into account
2019-05-13cpufreq: Don't find governor for setpolicy drivers in cpufreq_init_policy()Yue Hu1-51/+65
In cpufreq_init_policy() we will check if there's last_governor for target and setpolicy type. However last_governor is set only if has_target() is true in cpufreq_offline(). That means find last_governor for setpolicy type is pointless. Also new_policy.governor will not be used if ->setpolicy callback is set in cpufreq_set_policy(). Moreover, there's duplicate ->setpolicy check in using default policy path. Let's add a new helper function to avoid it. Also update comments. Signed-off-by: Yue Hu <huyue2@yulong.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-05-13cpufreq: Explain the kobject_put() in cpufreq_policy_alloc()Rafael J. Wysocki1-0/+5
It may not be particularly clear why the kobject_put() after failing kobject_init_and_add() in cpufreq_policy_alloc() is not redundant, so add a comment to explain that. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-05-10cpufreq: Call transition notifier only once for each policyViresh Kumar1-9/+10
Currently, the notifiers are called once for each CPU of the policy->cpus cpumask. It would be more optimal if the notifier can be called only once and all the relevant information be provided to it. Out of the 23 drivers that register for the transition notifiers today, only 4 of them do per-cpu updates and the callback for the rest can be called only once for the policy without any impact. This would also avoid multiple function calls to the notifier callbacks and reduce multiple iterations of notifier core's code (which does locking as well). This patch adds pointer to the cpufreq policy to the struct cpufreq_freqs, so the notifier callback has all the information available to it with a single call. The five drivers which perform per-cpu updates are updated to use the cpufreq policy. The freqs->cpu field is redundant now and is removed. Acked-by: David S. Miller <davem@davemloft.net> (sparc) Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-05-07Merge tag 'printk-for-5.2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - Allow state reset of printk_once() calls. - Prevent crashes when dereferencing invalid pointers in vsprintf(). Only the first byte is checked for simplicity. - Make vsprintf warnings consistent and inlined. - Treewide conversion of obsolete %pf, %pF to %ps, %pF printf modifiers. - Some clean up of vsprintf and test_printf code. * tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: lib/vsprintf: Make function pointer_string static vsprintf: Limit the length of inlined error messages vsprintf: Avoid confusion between invalid address and value vsprintf: Prevent crash when dereferencing invalid pointers vsprintf: Consolidate handling of unknown pointer specifiers vsprintf: Factor out %pO handler as kobject_string() vsprintf: Factor out %pV handler as va_format() vsprintf: Factor out %p[iI] handler as ip_addr_string() vsprintf: Do not check address of well-known strings vsprintf: Consistent %pK handling for kptr_restrict == 0 vsprintf: Shuffle restricted_pointer() printk: Tie printk_once / printk_deferred_once into .data.once for reset treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively lib/test_printf: Switch to bitmap_zalloc()
2019-04-30cpufreq: Fix kobject memleakViresh Kumar1-0/+1
Currently the error return path from kobject_init_and_add() is not followed by a call to kobject_put() - which means we are leaking the kobject. Fix it by adding a call to kobject_put() in the error path of kobject_init_and_add(). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Tobin C. Harding <tobin@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-23cpufreq: Move ->get callback check outside of __cpufreq_get()Yue Hu1-2/+3
Currenly, __cpufreq_get() called by show_cpuinfo_cur_freq() will check ->get callback. That is needless since cpuinfo_cur_freq attribute will not be created if ->get is not set. So let's drop it in __cpufreq_get(). Also keep this check in cpufreq_get(). Signed-off-by: Yue Hu <huyue2@yulong.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-17cpufreq: Remove needless bios_limit check in show_bios_limit()Yue Hu1-5/+3
Initially, bios_limit attribute will be created if driver->bios_limit is set in cpufreq_add_dev_interface(). So remove the redundant check for latter show operation. Signed-off-by: Yue Hu <huyue2@yulong.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-09treewide: Switch printk users from %pf and %pF to %ps and %pS, respectivelySakari Ailus1-1/+1
%pF and %pf are functionally equivalent to %pS and %ps conversion specifiers. The former are deprecated, therefore switch the current users to use the preferred variant. The changes have been produced by the following command: git grep -l '%p[fF]' | grep -v '^\(tools\|Documentation\)/' | \ while read i; do perl -i -pe 's/%pf/%ps/g; s/%pF/%pS/g;' $i; done And verifying the result. Link: http://lkml.kernel.org/r/20190325193229.23390-1-sakari.ailus@linux.intel.com Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: linux-arm-kernel@lists.infradead.org Cc: sparclinux@vger.kernel.org Cc: linux-um@lists.infradead.org Cc: xen-devel@lists.xenproject.org Cc: linux-acpi@vger.kernel.org Cc: linux-pm@vger.kernel.org Cc: drbd-dev@lists.linbit.com Cc: linux-block@vger.kernel.org Cc: linux-mmc@vger.kernel.org Cc: linux-nvdimm@lists.01.org Cc: linux-pci@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: linux-btrfs@vger.kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net Cc: linux-mm@kvack.org Cc: ceph-devel@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: David Sterba <dsterba@suse.com> (for btrfs) Acked-by: Mike Rapoport <rppt@linux.ibm.com> (for mm/memblock.c) Acked-by: Bjorn Helgaas <bhelgaas@google.com> (for drivers/pci) Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-04-09cpufreq: Remove cpufreq_driver check in cpufreq_boost_supported()Yue Hu1-1/+1
Currently there are three calling paths for cpufreq_boost_supported() in all as below, we can see the cpufreq_driver null check is needless since it is already checked before. <path1> cpufreq_enable_boost_support() |-> if (!cpufreq_driver) |-> cpufreq_boost_supported() <path2> cpufreq_register_driver() |-> if (!driver_data ... |-> cpufreq_driver = driver_data |-> cpufreq_boost_supported() |-> remove_boost_sysfs_file() |-> cpufreq_boost_supported() <path3> cpufreq_unregister_driver() |-> if (!cpufreq_driver ... |-> remove_boost_sysfs_file() |-> cpufreq_boost_supported() Signed-off-by: Yue Hu <huyue2@yulong.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-08cpufreq: intel_pstate: Update max frequency on global turbo changesRafael J. Wysocki1-12/+4
While the cpuinfo.max_freq value doesn't really matter for intel_pstate in the active mode, in the passive mode it is used by governors as the maximum physical frequency of the CPU and the results of governor computations generally depend on it. Also it is made available to user space via sysfs and it should match the current HW configuration. For this reason, make intel_pstate update cpuinfo.max_freq for all CPUs if it detects a global change of turbo frequency settings from "disable" to "enable" or the other way associated with a _PPC change notification from the platform firmware. Note that policy_is_inactive(), cpufreq_cpu_acquire(), cpufreq_cpu_release(), and cpufreq_set_policy() need to be made available to it for this purpose. Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759 Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-02cpufreq: Add cpufreq_cpu_acquire() and cpufreq_cpu_release()Rafael J. Wysocki1-9/+47
It sometimes is necessary to find a cpufreq policy for a given CPU and acquire its rwsem (for writing) immediately after that, so introduce cpufreq_cpu_acquire() as a helper for that and the complementary cpufreq_cpu_release(). Make cpufreq_update_policy() use the new functions. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-02cpufreq: intel_pstate: Driver-specific handling of _PPC updatesRafael J. Wysocki1-0/+16
In some cases, the platform firmware disables or enables turbo frequencies for all CPUs globally before triggering a _PPC change notification for one of them. Obviously, that global change affects all CPUs, not just the notified one, and it needs to be acted upon by cpufreq. The intel_pstate driver is able to detect such global changes of the settings, but it also needs to update policy limits for all CPUs if that happens, in particular if turbo frequencies are enabled globally - to allow them to be used. For this reason, introduce a new cpufreq driver callback to be invoked on _PPC notifications, if present, instead of simply calling cpufreq_update_policy() for the notified CPU and make intel_pstate use it to trigger policy updates for all CPUs in the system if global settings change. Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759 Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-03-07cpufreq: Improve kerneldoc comments for cpufreq_cpu_get/put()Rafael J. Wysocki1-15/+9
Fix the formatting of the cpufreq_cpu_get() and cpufreq_cpu_put() kerneldoc comments and rework them to be somewhat easier to follow. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-20cpufreq: Pass updated policy to driver ->setpolicy() callbackRafael J. Wysocki1-1/+1
The invocation of the ->setpolicy() cpufreq driver callback should be equivalent to calling cpufreq_governor_limits(policy) for drivers with internal governors, but in fact it isn't so, because the temporary new_policy object is passed to it instead of the updated policy. That is a bit confusing, so make cpufreq_set_policy() pass the updated policy to the driver ->setpolicy() callback. No intentional changes of behavior. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20cpufreq: Fix two debug messages in cpufreq_set_policy()Rafael J. Wysocki1-2/+2
Remove the redundant "cpufreq:" prefix from two debug messages in cpufreq_set_policy(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20cpufreq: Reorder and simplify cpufreq_update_policy()Rafael J. Wysocki1-12/+7
In cpufreq_update_policy(), instead of updating new_policy.cur separately, which is kind of confusing, because cpufreq_set_policy() doesn't take that value into account directly anyway, make the copy of the existing policy after calling cpufreq_update_current_freq(). No intentional changes of behavior. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20cpufreq: Add kerneldoc comments for two core functionsRafael J. Wysocki1-8/+24
Add kerneldoc comments describing cpufreq_set_policy() and cpufreq_update_policy() as they have not been properly documented so far and they really need to be documented. While at it, fix white space around the cpufreq_set_policy() header. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-14cpufreq: Replace double NOT (!!) with single NOT (!)Viresh Kumar1-1/+1
Double NOT (!!) operation is normally done to convert a non-zero value to 1 and keep zero as is, but that isn't the requirement in this case. All we wanted was to make sure that only one of the two routines isn't set, i.e. either both function pointers are set or both are unset. This can be done with a single NOT (!) operation as well. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-13cpufreq: Allow light-weight tear down and bring up of CPUsViresh Kumar1-20/+38
The cpufreq core doesn't remove the cpufreq policy anymore on CPU offline operation, rather that happens when the CPU device gets unregistered from the kernel. This allows faster recovery when the CPU comes back online. This is also very useful during system wide suspend/resume where we offline all non-boot CPUs during suspend and then bring them back on resume. This commit takes the same idea a step ahead to allow drivers to do light weight tear-down and bring-up during CPU offline and online operations. A new set of callbacks is introduced, online/offline(). online() gets called when the first CPU of an inactive policy is brought up and offline() gets called when all the CPUs of a policy are offlined. The existing init/exit() callback get called on policy creation/destruction. They also get called instead of online/offline() callbacks if the online/offline() callbacks aren't provided. This also moves around some code to get executed only for the new-policy case going forward. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-31cpufreq: Auto-register the driver as a thermal cooling device if askedAmit Kucheria1-0/+11
All cpufreq drivers do similar things to register as a cooling device. Provide a cpufreq driver flag so drivers can just ask the cpufreq core to register the cooling device on their behalf. This allows us to get rid of duplicated code in the drivers. In order to allow this, we add a struct thermal_cooling_device pointer to struct cpufreq_policy so that drivers don't need to store it in a private data structure. Suggested-by: Stephen Boyd <swboyd@chromium.org> Suggested-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Tested-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-29cpufreq: Use struct kobj_attribute instead of struct global_attrViresh Kumar1-3/+3
The cpufreq_global_kobject is created using kobject_create_and_add() helper, which assigns the kobj_type as dynamic_kobj_ktype and show/store routines are set to kobj_attr_show() and kobj_attr_store(). These routines pass struct kobj_attribute as an argument to the show/store callbacks. But all the cpufreq files created using the cpufreq_global_kobject expect the argument to be of type struct attribute. Things work fine currently as no one accesses the "attr" argument. We may not see issues even if the argument is used, as struct kobj_attribute has struct attribute as its first element and so they will both get same address. But this is logically incorrect and we should rather use struct kobj_attribute instead of struct global_attr in the cpufreq core and drivers and the show/store callbacks should take struct kobj_attribute as argument instead. This bug is caught using CFI CLANG builds in android kernel which catches mismatch in function prototypes for such callbacks. Reported-by: Donghee Han <dh.han@samsung.com> Reported-by: Sangkyu Kim <skwith.kim@samsung.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-16cpufreq: Don't update new_policy on failuresViresh Kumar1-2/+0
The local variable "new_policy" hasn't been used in the error path of cpufreq_online() since commit f9f41e3ef99a (cpufreq: Remove policy create/remove notifiers). Don't update it in that error path. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-11Merge branches 'pm-cpuidle', 'pm-cpufreq' and 'pm-sleep'Rafael J. Wysocki1-8/+4
* pm-cpuidle: doc: trace: fix reference to cpuidle documentation file cpuidle / Documentation: Update cpuidle MAINTAINERS entry * pm-cpufreq: cpufreq: scmi: Fix frequency invariance in slow path cpufreq: check if policy is inactive early in __cpufreq_get() cpufreq: scpi/scmi: Fix freeing of dynamic OPPs cpufreq / Documentation: Update cpufreq MAINTAINERS entry * pm-sleep: PM: sleep: call devfreq suspend/resume
2019-01-08cpufreq: check if policy is inactive early in __cpufreq_get()Sudeep Holla1-8/+4
cpuinfo_cur_freq gets current CPU frequency as detected by hardware while scaling_cur_freq last known CPU frequency. Some platforms may not allow checking the CPU frequency of an offline CPU or the associated resources may have been released via cpufreq_exit when the CPU gets offlined, in which case the policy would have been invalidated already. If we attempt to get current frequency from the hardware, it may result in hang or crash. For example on Juno, I see: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188 [0000000000000188] pgd=0000000000000000 Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: CPU: 5 PID: 4202 Comm: cat Not tainted 4.20.0-08251-ga0f2c0318a15-dirty #87 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform pstate: 40000005 (nZcv daif -PAN -UAO) pc : scmi_cpufreq_get_rate+0x34/0xb0 lr : scmi_cpufreq_get_rate+0x34/0xb0 Call trace: scmi_cpufreq_get_rate+0x34/0xb0 __cpufreq_get+0x34/0xc0 show_cpuinfo_cur_freq+0x24/0x78 show+0x40/0x60 sysfs_kf_seq_show+0xc0/0x148 kernfs_seq_show+0x44/0x50 seq_read+0xd4/0x480 kernfs_fop_read+0x15c/0x208 __vfs_read+0x60/0x188 vfs_read+0x94/0x150 ksys_read+0x6c/0xd8 __arm64_sys_read+0x24/0x30 el0_svc_common+0x78/0x100 el0_svc_handler+0x38/0x78 el0_svc+0x8/0xc ---[ end trace 3d1024e58f77f6b2 ]--- So fix the issue by checking if the policy is invalid early in __cpufreq_get before attempting to get the current frequency. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-12-11sched/topology: Make Energy Aware Scheduling depend on schedutilQuentin Perret1-0/+1
Energy Aware Scheduling (EAS) is designed with the assumption that frequencies of CPUs follow their utilization value. When using a CPUFreq governor other than schedutil, the chances of this assumption being true are small, if any. When schedutil is being used, EAS' predictions are at least consistent with the frequency requests. Although those requests have no guarantees to be honored by the hardware, they should at least guide DVFS in the right direction and provide some hope in regards to the EAS model being accurate. To make sure EAS is only used in a sane configuration, create a strong dependency on schedutil being used. Since having sugov compiled-in does not provide that guarantee, make CPUFreq call a scheduler function on governor changes hence letting it rebuild the scheduling domains, check the governors of the online CPUs, and enable/disable EAS accordingly. Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-9-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-09-10cpufreq: remove unnecessary unlikely()Igor Stoppa1-1/+1
WARN_ON() already contains an unlikely(), so it's not necessary to wrap it into another. Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-26cpufreq: Fix a circular lock dependency problemWaiman Long1-1/+6
With lockdep turned on, the following circular lock dependency problem was reported: [ 57.470040] ====================================================== [ 57.502900] WARNING: possible circular locking dependency detected [ 57.535208] 4.18.0-0.rc3.1.el8+7.x86_64+debug #1 Tainted: G [ 57.577761] ------------------------------------------------------ [ 57.609714] tuned/1505 is trying to acquire lock: [ 57.633808] 00000000559deec5 (cpu_hotplug_lock.rw_sem){++++}, at: store+0x27/0x120 [ 57.672880] [ 57.672880] but task is already holding lock: [ 57.702184] 000000002136ca64 (kn->count#118){++++}, at: kernfs_fop_write+0x1d0/0x410 [ 57.742176] [ 57.742176] which lock already depends on the new lock. [ 57.742176] [ 57.785220] [ 57.785220] the existing dependency chain (in reverse order) is: : [ 58.932512] other info that might help us debug this: [ 58.932512] [ 58.973344] Chain exists of: [ 58.973344] cpu_hotplug_lock.rw_sem --> subsys mutex#5 --> kn->count#118 [ 58.973344] [ 59.030795] Possible unsafe locking scenario: [ 59.030795] [ 59.061248] CPU0 CPU1 [ 59.085377] ---- ---- [ 59.108160] lock(kn->count#118); [ 59.124935] lock(subsys mutex#5); [ 59.156330] lock(kn->count#118); [ 59.186088] lock(cpu_hotplug_lock.rw_sem); [ 59.208541] [ 59.208541] *** DEADLOCK *** In the cpufreq_register_driver() function, the lock sequence is: cpus_read_lock --> kn->count For the cpufreq sysfs store method, the lock sequence is: kn->count --> cpus_read_lock These sequences are actually safe as they are taking a share lock on cpu_hotplug_lock. However, the current lockdep code doesn't check for share locking when detecting circular lock dependency. Fixing that could be a substantial effort. Instead, we can work around this problem by using cpus_read_trylock() in the store method which is much simpler. The chance of not getting the read lock is very small. If that happens, the userspace application that writes the sysfs file will get an error. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-26cpufreq: trace frequency limits changeRuchi Kandoi1-0/+1
systrace used for tracing for Android systems has carried a patch for many years in the Android tree that traces when the cpufreq limits change. With the help of this information, systrace can know when the policy limits change and can visually display the data. Lets add upstream support for the same. Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-30cpufreq: Use static SRCU initializerSebastian Andrzej Siewior1-12/+1
Use the static SRCU initializer for `cpufreq_transition_notifier_list'. This avoids the init_cpufreq_transition_notifier_list() initcall. Its only purpose is to initialize the SRCU notifier once during boot and set another variable which is used as an indicator whether the init was perfromed before cpufreq_register_notifier() was used. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-30cpufreq: Fix new policy initialization during limits updates via sysfsTao Wang1-0/+2
If the policy limits are updated via cpufreq_update_policy() and subsequently via sysfs, the limits stored in user_policy may be set incorrectly. For example, if both min and max are set via sysfs to the maximum available frequency, user_policy.min and user_policy.max will also be the maximum. If a policy notifier triggered by cpufreq_update_policy() lowers both the min and the max at this point, that change is not reflected by the user_policy limits, so if the max is updated again via sysfs to the same lower value, then user_policy.max will be lower than user_policy.min which shouldn't happen. In particular, if one of the policy CPUs is then taken offline and back online, cpufreq_set_policy() will fail for it due to a failing limits check. To prevent that from happening, initialize the min and max fields of the new_policy object to the ones stored in user_policy that were previously set via sysfs. Signed-off-by: Kevin Wangtao <kevin.wangtao@hisilicon.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Subject & changelog ] Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-13cpufreq: optimize cpufreq_notify_transition()Viresh Kumar1-31/+32
cpufreq_notify_transition() calls __cpufreq_notify_transition() for each CPU of a policy. There is a lot of code in __cpufreq_notify_transition() though which isn't required to be executed for each CPU, like checking about disabled cpufreq or irqs, adjusting jiffies, updating cpufreq stats and some debug print messages. This commit merges __cpufreq_notify_transition() into cpufreq_notify_transition() and modifies cpufreq_notify_transition() to execute minimum amount of code for each CPU. Also fix the kerneldoc for cpufreq_notify_transition() while at it. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-03-20cpufreq: Don't validate cpufreq table from cpufreq_generic_init()Viresh Kumar1-8/+1
The cpufreq table is already validated by the cpufreq core and none of the users of cpufreq_generic_init() have any dependency on it to validate the table as well. Don't validate the cpufreq table anymore from cpufreq_generic_init(). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-27cpufreq: Validate frequency table in the coreViresh Kumar1-4/+9
By design, cpufreq drivers are responsible for calling cpufreq_frequency_table_cpuinfo() from their ->init() callbacks to validate the frequency table. However, if a cpufreq driver is buggy and fails to do so properly, it lead to unexpected behavior of the driver or the cpufreq core at a later point in time. It would be better if the core could validate the frequency table during driver initialization. To that end, introduce cpufreq_table_validate_and_sort() and make the cpufreq core call it right after invoking the ->init() callback of the driver and destroy the cpufreq policy if the table is invalid. For the time being the validation of the table happens twice, once from the driver and then from the core. The individual drivers will be updated separately to drop table validation if they don't need it for other reasons. The frequency table is marked "sorted" or "unsorted" by the new helper now instead of in cpufreq_table_validate_and_show(), as it should only be done after validating the table (which the drivers won't do going forward). Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Subject/changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-27cpufreq: Reorder cpufreq_online() error code pathViresh Kumar1-3/+3
Ideally the de-allocation of resources should happen in the exact opposite order in which they were allocated. It helps maintain the code in long term, even if nothing really breaks with incorrect ordering. That wasn't followed in cpufreq_online() and it has some inconsistencies. For example, the symlinks were created from within the locked region while they are removed only after putting the locks. Also ->exit() should have been called only after the symlinks are removed and the lock is dropped, as that was the case when ->init() was first called. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-05cpufreq: Skip cpufreq resume if it's not suspendedBo Yan1-0/+3
cpufreq_resume can be called even without preceding cpufreq_suspend. This can happen in following scenario: suspend_devices_and_enter --> dpm_suspend_start --> dpm_prepare --> device_prepare : this function errors out --> dpm_suspend: this is skipped due to dpm_prepare failure this means cpufreq_suspend is skipped over --> goto Recover_platform, due to previous error --> goto Resume_devices --> dpm_resume_end --> dpm_resume --> cpufreq_resume In case schedutil is used as frequency governor, cpufreq_resume will eventually call sugov_start, which does following: memset(sg_cpu, 0, sizeof(*sg_cpu)); .... This effectively erases function pointer for frequency update, causing crash later on. The function pointer would have been set correctly if subsequent cpufreq_add_update_util_hook runs successfully, but that function returns earlier because cpufreq_suspend was not called: if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) return; The fix is to check cpufreq_suspended first, if it's false, that means cpufreq_suspend was not called in the first place, so do not resume cpufreq. Signed-off-by: Bo Yan <byan@nvidia.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Dropped printing a message ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04cpufreq: Fix governor module removal raceRafael J. Wysocki1-0/+6
It is possible to remove a cpufreq governor module after cpufreq_parse_governor() has returned success in store_scaling_governor() and before cpufreq_set_policy() acquires a reference to it, because the governor list is not protected during that period and nothing prevents the governor from being unregistered then. Prevent that from happening by acquiring an extra reference to the governor module temporarily in cpufreq_parse_governor(), under cpufreq_governor_mutex, and dropping it in store_scaling_governor(), when cpufreq_set_policy() returns. Note that the second cpufreq_parse_governor() call site is fine, because it only cares about the policy member of new_policy. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04cpufreq: Drop pointless return statementRafael J. Wysocki1-1/+0
Drop a pointless return statement from cpufreq_unregister_governor(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04cpufreq: Pass policy pointer to cpufreq_parse_governor()Rafael J. Wysocki1-9/+7
Pass policy pointer to cpufreq_parse_governor() instead of passing pointers to two members of it so as to make the code slightly more straightforward. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04cpufreq: Clean up cpufreq_parse_governor()Rafael J. Wysocki1-15/+17
Drop an unnecessary local variable from cpufreq_parse_governor() and rearrange the code in there to make it easier to follow. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-10-03cpufreq: provide default frequency-invariance setter functionDietmar Eggemann1-0/+6
Frequency-invariant accounting support based on the ratio of current frequency and maximum supported frequency is an optional feature an arch can implement. Since there are cpufreq drivers (e.g. cpufreq-dt) which can be build for different arch's a default implementation of the frequency-invariance setter function arch_set_freq_scale() is needed. This default implementation is an empty weak function which will be overwritten by a strong function in case the arch provides one. The setter function passes the cpumask of related (to the frequency change) cpus (online and offline cpus), the (new) current frequency and the maximum supported frequency. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-09-04Merge branch 'pm-cpufreq-sched'Rafael J. Wysocki1-3/+4
* pm-cpufreq-sched: cpufreq: schedutil: Always process remote callback with slow switching cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily cpufreq: Return 0 from ->fast_switch() on errors cpufreq: Simplify cpufreq_can_do_remote_dvfs() cpufreq: Process remote callbacks from any CPU if the platform permits sched: cpufreq: Allow remote cpufreq callbacks cpufreq: schedutil: Use unsigned int for iowait boost cpufreq: schedutil: Make iowait boost more energy efficient
2017-08-22cpufreq: Cap the default transition delay value to 10 msViresh Kumar1-2/+13
If transition_delay_us isn't defined by the cpufreq driver, the default value of transition delay (time after which the cpufreq governor will try updating the frequency again) is currently calculated by multiplying transition_latency (nsec) with LATENCY_MULTIPLIER (1000) and then converting this time to usec. That gives the exact same value as transition_latency, just that the time unit is usec instead of nsec. With acpi-cpufreq for example, transition_latency is set to around 10 usec and we get transition delay as 10 ms. Which seems to be a reasonable amount of time to reevaluate the frequency again. But for platforms where frequency switching isn't that fast (like ARM), the transition_latency varies from 500 usec to 3 ms, and the transition delay becomes 500 ms to 3 seconds. Of course, that is a pretty bad default value to start with. We can try to come across a better formula (instead of multiplying with LATENCY_MULTIPLIER) to solve this problem, but will that be worth it ? This patch tries a simple approach and caps the maximum value of default transition delay to 10 ms. Of course, userspace can still come in and change this value anytime or individual drivers can rather provide transition_delay_us instead. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-10cpufreq: Return 0 from ->fast_switch() on errorsViresh Kumar1-3/+4
CPUFREQ_ENTRY_INVALID is a special symbol which is used to specify that an entry in the cpufreq table is invalid. But using it outside of the scope of the cpufreq table looks a bit incorrect. We can represent an invalid frequency by writing it as 0 instead if we need. Note that it is already done that way for the return value of the ->get() callback. Lets do the same for ->fast_switch() and not use CPUFREQ_ENTRY_INVALID outside of the scope of cpufreq table. Also update the comment over cpufreq_driver_fast_switch() to clearly mention what this returns. None of the drivers return CPUFREQ_ENTRY_INVALID as of now from ->fast_switch() callback and so we don't need to update any of those. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26cpufreq: Allow dynamic switching with CPUFREQ_ETERNAL latencyViresh Kumar1-2/+1
With the recent updates, CPUFREQ_ETERNAL is only used by the drivers which don't know their transition latency but want to use dynamic switching. Anyway, the routine cpufreq_policy_transition_delay_us() caps the value of transition latency to 10 ms now and that can be used safely with such platforms. Remove the check from cpufreq_init_governor() and allow dynamic switching for such configurations as well. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26cpufreq: Add CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING cpufreq driver flagViresh Kumar1-2/+3
The policy->transition_latency field is used for multiple purposes today and its not straight forward at all. This is how it is used: A. Set the correct transition_latency value. B. Set it to CPUFREQ_ETERNAL because: 1. We don't want automatic dynamic switching (with ondemand/conservative) to happen at all. 2. We don't know the transition latency. This patch handles the B.1. case in a more readable way. A new flag for the cpufreq drivers is added to disallow use of cpufreq governors which have dynamic_switching flag set. All the current cpufreq drivers which are setting transition_latency unconditionally to CPUFREQ_ETERNAL are updated to use it. They don't need to set transition_latency anymore. There shouldn't be any functional change after this patch. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26cpufreq: Replace "max_transition_latency" with "dynamic_switching"Viresh Kumar1-4/+4
There is no limitation in the ondemand or conservative governors which disallow the transition_latency to be greater than 10 ms. The max_transition_latency field is rather used to disallow automatic dynamic frequency switching for platforms which didn't wanted these governors to run. Replace max_transition_latency with a boolean (dynamic_switching) and check for transition_latency == CPUFREQ_ETERNAL along with that. This makes it pretty straight forward to read/understand now. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22cpufreq: Use transition_delay_us for legacy governors as wellViresh Kumar1-0/+15
The policy->transition_delay_us field is used only by the schedutil governor currently, and this field describes how fast the driver wants the cpufreq governor to change CPUs frequency. It should rather be a common thing across all governors, as it doesn't have any schedutil dependency here. Create a new helper cpufreq_policy_transition_delay_us() to get the transition delay across all governors. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-04Merge tag 'pm-4.13-rc1' of ↵Linus Torvalds1-1/+11
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "The big ticket items here are the rework of suspend-to-idle in order to add proper support for power button wakeup from it on recent Dell laptops and the rework of interfaces exporting the current CPU frequency on x86. In addition to that, support for a few new pieces of hardware is added, the PCI/ACPI device wakeup infrastructure is simplified significantly and the wakeup IRQ framework is fixed to unbreak the IRQ bus locking infrastructure. Also, there are some functional improvements for intel_pstate, tools updates and small fixes and cleanups all over. Specifics: - Rework suspend-to-idle to allow it to take wakeup events signaled by the EC into account on ACPI-based platforms in order to properly support power button wakeup from suspend-to-idle on recent Dell laptops (Rafael Wysocki). That includes the core suspend-to-idle code rework, support for the Low Power S0 _DSM interface, and support for the ACPI INT0002 Virtual GPIO device from Hans de Goede (required for USB keyboard wakeup from suspend-to-idle to work on some machines). - Stop trying to export the current CPU frequency via /proc/cpuinfo on x86 as that is inaccurate and confusing (Len Brown). - Rework the way in which the current CPU frequency is exported by the kernel (over the cpufreq sysfs interface) on x86 systems with the APERF and MPERF registers by always using values read from these registers, when available, to compute the current frequency regardless of which cpufreq driver is in use (Len Brown). - Rework the PCI/ACPI device wakeup infrastructure to remove the questionable and artificial distinction between "devices that can wake up the system from sleep states" and "devices that can generate wakeup signals in the working state" from it, which allows the code to be simplified quite a bit (Rafael Wysocki). - Fix the wakeup IRQ framework by making it use SRCU instead of RCU which doesn't allow sleeping in the read-side critical sections, but which in turn is expected to be allowed by the IRQ bus locking infrastructure (Thomas Gleixner). - Modify some computations in the intel_pstate driver to avoid rounding errors resulting from them (Srinivas Pandruvada). - Reduce the overhead of the intel_pstate driver in the HWP (hardware-managed P-states) mode and when the "performance" P-state selection algorithm is in use by making it avoid registering scheduler callbacks in those cases (Len Brown). - Rework the energy_performance_preference sysfs knob in intel_pstate by changing the values that correspond to different symbolic hint names used by it (Len Brown). - Make it possible to use more than one cpuidle driver at the same time on ARM (Daniel Lezcano). - Make it possible to prevent the cpuidle menu governor from using the 0 state by disabling it via sysfs (Nicholas Piggin). - Add support for FFH (Fixed Functional Hardware) MWAIT in ACPI C1 on AMD systems (Yazen Ghannam). - Make the CPPC cpufreq driver take the lowest nonlinear performance information into account (Prashanth Prakash). - Add support for hi3660 to the cpufreq-dt driver, fix the imx6q driver and clean up the sfi, exynos5440 and intel_pstate drivers (Colin Ian King, Krzysztof Kozlowski, Octavian Purdila, Rafael Wysocki, Tao Wang). - Fix a few minor issues in the generic power domains (genpd) framework and clean it up somewhat (Krzysztof Kozlowski, Mikko Perttunen, Viresh Kumar). - Fix a couple of minor issues in the operating performance points (OPP) framework and clean it up somewhat (Viresh Kumar). - Fix a CONFIG dependency in the hibernation core and clean it up slightly (Balbir Singh, Arvind Yadav, BaoJun Luo). - Add rk3228 support to the rockchip-io adaptive voltage scaling (AVS) driver (David Wu). - Fix an incorrect bit shift operation in the RAPL power capping driver (Adam Lessnau). - Add support for the EPP field in the HWP (hardware managed P-states) control register, HWP.EPP, to the x86_energy_perf_policy tool and update msr-index.h with HWP.EPP values (Len Brown). - Fix some minor issues in the turbostat tool (Len Brown). - Add support for AMD family 0x17 CPUs to the cpupower tool and fix a minor issue in it (Sherry Hurwitz). - Assorted cleanups, mostly related to the constification of some data structures (Arvind Yadav, Joe Perches, Kees Cook, Krzysztof Kozlowski)" * tag 'pm-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (69 commits) cpufreq: Update scaling_cur_freq documentation cpufreq: intel_pstate: Clean up after performance governor changes PM: hibernate: constify attribute_group structures. cpuidle: menu: allow state 0 to be disabled intel_idle: Use more common logging style PM / Domains: Fix missing default_power_down_ok comment PM / Domains: Fix unsafe iteration over modified list of domains PM / Domains: Fix unsafe iteration over modified list of domain providers PM / Domains: Fix unsafe iteration over modified list of device links PM / Domains: Handle safely genpd_syscore_switch() call on non-genpd device PM / Domains: Call driver's noirq callbacks PM / core: Drop run_wake flag from struct dev_pm_info PCI / PM: Simplify device wakeup settings code PCI / PM: Drop pme_interrupt flag from struct pci_dev ACPI / PM: Consolidate device wakeup settings code ACPI / PM: Drop run_wake from struct acpi_device_wakeup_flags PM / QoS: constify *_attribute_group. PM / AVS: rockchip-io: add io selectors and supplies for rk3228 powercap/RAPL: prevent overridding bits outside of the mask PM / sysfs: Constify attribute groups ...
2017-07-04Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds1-10/+11
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull SMP hotplug updates from Thomas Gleixner: "This update is primarily a cleanup of the CPU hotplug locking code. The hotplug locking mechanism is an open coded RWSEM, which allows recursive locking. The main problem with that is the recursive nature as it evades the full lockdep coverage and hides potential deadlocks. The rework replaces the open coded RWSEM with a percpu RWSEM and establishes full lockdep coverage that way. The bulk of the changes fix up recursive locking issues and address the now fully reported potential deadlocks all over the place. Some of these deadlocks have been observed in the RT tree, but on mainline the probability was low enough to hide them away." * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) cpu/hotplug: Constify attribute_group structures powerpc: Only obtain cpu_hotplug_lock if called by rtasd ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init cpu/hotplug: Remove unused check_for_tasks() function perf/core: Don't release cred_guard_mutex if not taken cpuhotplug: Link lock stacks for hotplug callbacks acpi/processor: Prevent cpu hotplug deadlock sched: Provide is_percpu_thread() helper cpu/hotplug: Convert hotplug locking to percpu rwsem s390: Prevent hotplug rwsem recursion arm: Prevent hotplug rwsem recursion arm64: Prevent cpu hotplug rwsem recursion kprobes: Cure hotplug lock ordering issues jump_label: Reorder hotplug lock and jump_label_lock perf/tracing/cpuhotplug: Fix locking order ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() PCI: Replace the racy recursion prevention PCI: Use cpu_hotplug_disable() instead of get_online_cpus() perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() x86/perf: Drop EXPORT of perf_check_microcode ...