kernel.git/drivers/cpufreq/cpufreq.c, branch linux-4.10.y

cpufreq: Bring CPUs up even if cpufreq_online() failed

2017-04-21T07:32:40Z

commit c4a3fa261b16858416f1fd7db03a33d7ef5fc0b3 upstream. There is a report that after commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine"), the normal CPU offline/online cycle fails on some platforms. According to the ftrace result, this problem was triggered on platforms using acpi-cpufreq as the default cpufreq driver, and due to the lack of some ACPI freq method (eg. _PCT), cpufreq_online() failed and returned a negative value, so the CPU hotplug state machine rolled back the CPU online process. Actually, from the user's perspective, the failure of cpufreq_online() should not prevent that CPU from being brought up, although cpufreq might not work on that CPU. BTW, during system startup cpufreq_online() is not invoked via CPU online but by the cpufreq device creation process, so the APs can be brought up even though cpufreq_online() fails in that stage. This patch ignores the return value of cpufreq_online/offline() and lets the cpufreq framework deal with the failure. cpufreq_online() itself will do a proper rollback in that case and if _PCT is missing, the ACPI cpufreq driver will print a warning if the corresponding debug options have been enabled. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=194581 Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine") Reported-and-tested-by: Tomasz Maciej Nowak Signed-off-by: Chen Yu Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

cpufreq: Restore policy min/max limits on CPU online

2017-03-30T07:44:08Z

commit ff010472fb75670cb5c08671e820eeea3af59c87 upstream. On CPU online the cpufreq core restores the previous governor (or the previous "policy" setting for ->setpolicy drivers), but it does not restore the min/max limits at the same time, which is confusing, inconsistent and real pain for users who set the limits and then suspend/resume the system (using full suspend), in which case the limits are reset on all CPUs except for the boot one. Fix this by making cpufreq_online() restore the limits when an inactive policy is brought online. The commit log and patch are inspired from Rafael's earlier work. Reported-by: Rafael J. Wysocki Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

cpufreq: Fix and clean up show_cpuinfo_cur_freq()

2017-03-26T11:08:11Z

commit 9b4f603e7a9f4282aec451063ffbbb8bb410dcd9 upstream. There is a missing newline in show_cpuinfo_cur_freq(), so add it, but while at it clean that function up somewhat too. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Greg Kroah-Hartman

cpufreq: Make cpufreq_update_policy() void

2016-11-21T13:35:43Z

The return value of cpufreq_update_policy() is never used, so make it void. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar

cpufreq: Avoid using inactive policies

2016-11-21T13:35:42Z

There are two places in the cpufreq core in which low-level driver callbacks may be invoked for an inactive cpufreq policy, which isn't guaranteed to work in general. Both are due to possible races with CPU offline. First, in cpufreq_get(), the policy may become inactive after the check against policy->cpus in cpufreq_cpu_get() and before policy->rwsem is acquired, in which case using it going forward may not be correct. Second, an analogous situation is possible in cpufreq_update_policy(). Avoid using inactive policies by adding policy_is_inactive() checks to the code in the above places. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar

Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-10-04T02:43:08Z

Pull CPU hotplug updates from Thomas Gleixner: "Yet another batch of cpu hotplug core updates and conversions: - Provide core infrastructure for multi instance drivers so the drivers do not have to keep custom lists. - Convert custom lists to the new infrastructure. The block-mq custom list conversion comes through the block tree and makes the diffstat tip over to more lines removed than added. - Handle unbalanced hotplug enable/disable calls more gracefully. - Remove the obsolete CPU_STARTING/DYING notifier support. - Convert another batch of notifier users. The relayfs changes which conflicted with the conversion have been shipped to me by Andrew. The remaining lot is targeted for 4.10 so that we finally can remove the rest of the notifiers" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits) cpufreq: Fix up conversion to hotplug state machine blk/mq: Reserve hotplug states for block multiqueue x86/apic/uv: Convert to hotplug state machine s390/mm/pfault: Convert to hotplug state machine mips/loongson/smp: Convert to hotplug state machine mips/octeon/smp: Convert to hotplug state machine fault-injection/cpu: Convert to hotplug state machine padata: Convert to hotplug state machine cpufreq: Convert to hotplug state machine ACPI/processor: Convert to hotplug state machine virtio scsi: Convert to hotplug state machine oprofile/timer: Convert to hotplug state machine block/softirq: Convert to hotplug state machine lib/irq_poll: Convert to hotplug state machine x86/microcode: Convert to hotplug state machine sh/SH-X3 SMP: Convert to hotplug state machine ia64/mca: Convert to hotplug state machine ARM/OMAP/wakeupgen: Convert to hotplug state machine ARM/shmobile: Convert to hotplug state machine arm64/FP/SIMD: Convert to hotplug state machine ...

cpufreq: Fix up conversion to hotplug state machine

2016-09-20T14:59:21Z

The function cpufreq_register_driver() returns zero on success and since commit 27622b061eb4 ("cpufreq: Convert to hotplug state machine") erroneously a positive number. Due to the "if (x) assume_error" construct all callers assumed an error and as a consequence the cpu freq kworker crashes with a NULL pointer dereference. Reset the return value back to zero in the success case. Fixes: 27622b061eb4 ("cpufreq: Convert to hotplug state machine") Reported-by: Borislav Petkov Reported-and-tested-by: Ingo Molnar Signed-off-by: Sebastian Andrzej Siewior Cc: peterz@infradead.org Cc: rjw@rjwysocki.net Link: http://lkml.kernel.org/r/20160920145628.lp2bmq72ip3oiash@linutronix.de Signed-off-by: Thomas Gleixner

cpufreq: Convert to hotplug state machine

2016-09-19T19:44:29Z

Install the callbacks via the state machine. Signed-off-by: Sebastian Andrzej Siewior Acked-by: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra Cc: Viresh Kumar

cpufreq: create link to policy only for registered CPUs

2016-09-13T00:41:15Z

If a cpufreq driver is registered very early in the boot stage (e.g. registered from postcore_initcall()), then cpufreq core may generate kernel warnings for it. In this case, the CPUs are brought online, then the cpufreq driver is registered, and then the CPU topology devices are registered. However, by the time cpufreq_add_dev() gets called, the cpu device isn't stored in the per-cpu variable (cpu_sys_devices,) which is read by get_cpu_device(). So the cpufreq core fails to get device for the CPU, for which cpufreq_add_dev() was called in the first place and we will hit a WARN_ON(!cpu_dev). Even if we reuse the 'dev' parameter passed to cpufreq_add_dev() to avoid that warning, there might be other CPUs online that share the policy with the cpu for which cpufreq_add_dev() is called. Eventually get_cpu_device() will return NULL for them as well, and we will hit the same WARN_ON() again. In order to fix these issues, change cpufreq core to create links to the policy for a cpu only when cpufreq_add_dev() is called for that CPU. Reuse the 'real_cpus' mask to track that as well. Note that cpufreq_remove_dev() already handles removal of the links for individual CPUs and cpufreq_add_dev() has aligned with that now. Reported-by: Russell King Tested-by: Russell King Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Drop unnecessary check from cpufreq_policy_alloc()

2016-08-31T22:29:10Z

Since cpufreq_policy_alloc() doesn't use its dev variable for anything useful, drop that variable from there along with the NULL check against it. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar