From 21e018235d99bc86249b034c06646df8757b2852 Mon Sep 17 00:00:00 2001 From: Christian Loehle Date: Wed, 16 Sep 2026 17:28:04 +0100 Subject: cpufreq: CPPC: Select the frequency-invariance callback per CPU cppc_cpufreq_cpu_fie_init() initializes deferred work only for CPUs whose feedback counters use PCC. However, if any CPU in a shared policy uses PCC, it installs the PCC tick callback for the entire policy. With FIE enabled, a non-PCC CPU then queues an uninitialized irq_work and can call a NULL function pointer when that work runs. Choose the frequency-invariance callback separately for each CPU using the recorded work-initialization state. Processor removal can unpublish the CPC descriptor before callback registration, so querying its counter transport again can incorrectly select direct reads for a PCC CPU. Register the callbacks after all counter initialization has completed, so a failed initial read for an online CPU cannot leave a partially registered policy. PCC CPUs use their initialized deferred work, while non-PCC CPUs read their own counters directly from the tick. Fixes: 997c021abc6e ("cpufreq: CPPC: Update FIE arch_freq_scale in ticks for non-PCC regs") Cc: All applicable Signed-off-by: Christian Loehle Tested-by: Sumit Gupta Link: https://patch.msgid.link/20260916162805.1039247-20-christian.loehle@arm.com Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cppc_cpufreq.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'drivers/cpufreq') diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 9dde24d3e645..c0fa9073e4d3 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -150,7 +150,7 @@ static struct scale_freq_data cppc_sftd_pcc = { static void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy) { - struct scale_freq_data *sftd = &cppc_sftd; + struct scale_freq_data *sftd; struct cppc_freq_invariance *cppc_fi; int cpu, ret; @@ -165,7 +165,6 @@ static void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy) kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn); init_irq_work(&cppc_fi->irq_work, cppc_irq_work); cppc_fi->pcc_work_initialized = true; - sftd = &cppc_sftd_pcc; } ret = cppc_get_perf_ctrs(cpu, &cppc_fi->prev_perf_fb_ctrs); @@ -181,8 +180,15 @@ static void cppc_cpufreq_cpu_fie_init(struct cpufreq_policy *policy) } } - /* Register for freq-invariance */ - topology_set_scale_freq_source(sftd, policy->cpus); + /* A shared policy may contain both PCC and non-PCC counters. */ + for_each_cpu(cpu, policy->cpus) { + cppc_fi = &per_cpu(cppc_freq_inv, cpu); + if (cppc_fi->pcc_work_initialized) + sftd = &cppc_sftd_pcc; + else + sftd = &cppc_sftd; + topology_set_scale_freq_source(sftd, cpumask_of(cpu)); + } } /* -- cgit v1.2.3