From 0a10d3fe3e5c601031676e81b41fb2977650b4d4 Mon Sep 17 00:00:00 2001 From: Ionela Voinescu Date: Tue, 1 Sep 2020 21:55:45 +0100 Subject: arch_topology: validate input frequencies to arch_set_freq_scale() The current frequency passed to arch_set_freq_scale() could end up being 0, signaling an error in setting a new frequency. Also, if the maximum frequency in 0, this will result in a division by 0 error. Therefore, validate these input values before using them for the setting of the frequency scale factor. Signed-off-by: Ionela Voinescu Acked-by: Viresh Kumar Reviewed-by: Sudeep Holla Signed-off-by: Rafael J. Wysocki --- drivers/base/arch_topology.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/base') diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 75f72d684294..42a08ef693ae 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -33,6 +33,9 @@ void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, unsigned long scale; int i; + if (WARN_ON_ONCE(!cur_freq || !max_freq)) + return; + /* * If the use of counters for FIE is enabled, just return as we don't * want to update the scale factor with information from CPUFREQ. -- cgit v1.2.3 From ecddc3a0d5d752071c627aa1a1d4d7b529ddae67 Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Tue, 1 Sep 2020 21:55:48 +0100 Subject: arch_topology, cpufreq: constify arch_* cpumasks The passed cpumask arguments to arch_set_freq_scale() and arch_freq_counters_available() are only iterated over, so reflect this in the prototype. This also allows to pass system cpumasks like cpu_online_mask without getting a warning. Signed-off-by: Valentin Schneider Signed-off-by: Ionela Voinescu Acked-by: Catalin Marinas Acked-by: Viresh Kumar Reviewed-by: Sudeep Holla Signed-off-by: Rafael J. Wysocki --- drivers/base/arch_topology.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 42a08ef693ae..91de5331ac8a 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -21,13 +21,13 @@ #include #include -__weak bool arch_freq_counters_available(struct cpumask *cpus) +__weak bool arch_freq_counters_available(const struct cpumask *cpus) { return false; } DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE; -void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, +void arch_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq, unsigned long max_freq) { unsigned long scale; -- cgit v1.2.3 From 15e5d5b45b2b7072214af519357a1c0af078c50b Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Tue, 1 Sep 2020 21:55:49 +0100 Subject: arch_topology, arm, arm64: define arch_scale_freq_invariant() arch_scale_freq_invariant() is used by schedutil to determine whether the scheduler's load-tracking signals are frequency invariant. Its definition is overridable, though by default it is hardcoded to 'true' if arch_scale_freq_capacity() is defined ('false' otherwise). This behaviour is not overridden on arm, arm64 and other users of the generic arch topology driver, which is somewhat precarious: arch_scale_freq_capacity() will always be defined, yet not all cpufreq drivers are guaranteed to drive the frequency invariance scale factor setting. In other words, the load-tracking signals may very well *not* be frequency invariant. Now that cpufreq can be queried on whether the current driver is driving the Frequency Invariance (FI) scale setting, the current situation can be improved. This combines the query of whether cpufreq supports the setting of the frequency scale factor, with whether all online CPUs are counter-based FI enabled. While cpufreq FI enablement applies at system level, for all CPUs, counter-based FI support could also be used for only a subset of CPUs to set the invariance scale factor. Therefore, if cpufreq-based FI support is present, we consider the system to be invariant. If missing, we require all online CPUs to be counter-based FI enabled in order for the full system to be considered invariant. If the system ends up not being invariant, a new condition is needed in the counter initialization code that disables all scale factor setting based on counters. Precedence of counters over cpufreq use is not important here. The invariant status is only given to the system if all CPUs have at least one method of setting the frequency scale factor. Signed-off-by: Valentin Schneider Signed-off-by: Ionela Voinescu Acked-by: Catalin Marinas Acked-by: Viresh Kumar Reviewed-by: Sudeep Holla Signed-off-by: Rafael J. Wysocki --- drivers/base/arch_topology.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/base') diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 91de5331ac8a..89cae168b076 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -21,6 +21,12 @@ #include #include +bool topology_scale_freq_invariant(void) +{ + return cpufreq_supports_freq_invariance() || + arch_freq_counters_available(cpu_online_mask); +} + __weak bool arch_freq_counters_available(const struct cpumask *cpus) { return false; -- cgit v1.2.3