Commit 38e480d4 authored by Beata Michalska's avatar Beata Michalska Committed by Catalin Marinas
Browse files

cpufreq: Allow arch_freq_get_on_cpu to return an error 



Allow arch_freq_get_on_cpu to return an error for cases when retrieving
current CPU frequency is not possible, whether that being due to lack of
required arch support or due to other circumstances when the current
frequency cannot be determined at given point of time.

Signed-off-by: default avatarBeata Michalska <beata.michalska@arm.com>
Reviewed-by: default avatarPrasanna Kumar T S M <ptsm@linux.microsoft.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Acked-by: default avatarRafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20250131162439.3843071-2-beata.michalska@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 004b500a

arch/x86/kernel/cpu/aperfmperf.c

+1 −1
Original line number Diff line number Diff line
@@ -498,7 +498,7 @@ void arch_scale_freq_tick(void) 
 */

#define MAX_SAMPLE_AGE	((unsigned long)HZ / 50)



unsigned int arch_freq_get_on_cpu(int cpu)

int arch_freq_get_on_cpu(int cpu)

{

	struct aperfmperf *s = per_cpu_ptr(&cpu_samples, cpu);

	unsigned int seq, freq;

arch/x86/kernel/cpu/proc.c

+5 −2
Original line number Diff line number Diff line
@@ -86,8 +86,11 @@ static int show_cpuinfo(struct seq_file *m, void *v) 
		seq_printf(m, "microcode\t: 0x%x\n", c->microcode);



	if (cpu_has(c, X86_FEATURE_TSC)) {

		unsigned int freq = arch_freq_get_on_cpu(cpu);

		int freq = arch_freq_get_on_cpu(cpu);



		if (freq < 0)

			seq_puts(m, "cpu MHz\t\t: Unknown\n");

		else

			seq_printf(m, "cpu MHz\t\t: %u.%03u\n", freq / 1000, (freq % 1000));

	}

drivers/cpufreq/cpufreq.c

+4 −4
Original line number Diff line number Diff line
@@ -729,18 +729,18 @@ show_one(cpuinfo_transition_latency, cpuinfo.transition_latency); 
show_one(scaling_min_freq, min);

show_one(scaling_max_freq, max);



__weak unsigned int arch_freq_get_on_cpu(int cpu)

__weak int arch_freq_get_on_cpu(int cpu)

{

	return 0;

	return -EOPNOTSUPP;

}



static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)

{

	ssize_t ret;

	unsigned int freq;

	int freq;



	freq = arch_freq_get_on_cpu(policy->cpu);

	if (freq)

	if (freq > 0)

		ret = sysfs_emit(buf, "%u\n", freq);

	else if (cpufreq_driver->setpolicy && cpufreq_driver->get)

		ret = sysfs_emit(buf, "%u\n", cpufreq_driver->get(policy->cpu));

include/linux/cpufreq.h

+1 −1
Original line number Diff line number Diff line
@@ -1184,7 +1184,7 @@ static inline int of_perf_domain_get_sharing_cpumask(int pcpu, const char *list_ 
}

#endif



extern unsigned int arch_freq_get_on_cpu(int cpu);

extern int arch_freq_get_on_cpu(int cpu);



#ifndef arch_set_freq_scale

static __always_inline