diff options
| author | Christian Loehle <christian.loehle@arm.com> | 2026-09-16 17:28:04 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-09-18 17:29:09 +0200 |
| commit | 21e018235d99bc86249b034c06646df8757b2852 (patch) | |
| tree | 948c100fb9bd6240599f7f473a99ad6e8e9d662a /drivers/cpufreq | |
| parent | 4bcc60d326c5acaa28c5913259decb22a33a83a1 (diff) | |
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 <stable@vger.kernel.org>
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Tested-by: Sumit Gupta <sumitg@nvidia.com>
Link: https://patch.msgid.link/20260916162805.1039247-20-christian.loehle@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 14 |
1 files changed, 10 insertions, 4 deletions
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)); + } } /* |