!849 drivers/cpufreq: gain accurate CPU frequency from cpufreq/cpuinfo_cur_freq

Merge Pull Request from: @henryze 
 
When users want to get frequency by cpuinfo_cur_freq under cpufreq sysfs,
they often get the invalid result like:

$ cat /sys/devices/system/cpu/cpu6/cpufreq/cpuinfo_cur_freq
4294967295

So this series provides fixes to the concerned issue.

Reference: https://lore.kernel.org/all/20230516133248.712242-3-zengheng4@huawei.com/ 
 
Link:https://gitee.com/openeuler/kernel/pulls/849 

Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> 
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> 

arch/arm64/configs/openeuler_defconfig

@@ -488,7 +488,7 @@ CONFIG_AS_HAS_CFI_NEGATE_RA_STATE=y
 #
 # ARMv8.4 architectural features
 #
-# CONFIG_ARM64_AMU_EXTN is not set
+CONFIG_ARM64_AMU_EXTN=y
 CONFIG_AS_HAS_ARMV8_4=y
 CONFIG_ARM64_TLB_RANGE=y
 # end of ARMv8.4 architectural features

arch/arm64/kernel/cpufeature.c

@@ -1588,6 +1588,7 @@ bool cpu_has_amu_feat(int cpu)
 {
 	return cpumask_test_cpu(cpu, &amu_cpus);
 }
+EXPORT_SYMBOL(cpu_has_amu_feat);
 
 int get_cpu_with_amu_feat(void)
 {

drivers/cpufreq/cppc_cpufreq.c

@@ -350,23 +350,37 @@ static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
 	return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
 }
 
-static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
+static int cppc_get_perf_ctrs_sample(void *val)
 {
-	struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
-	struct cppc_cpudata *cpu = all_cpu_data[cpunum];
+	int cpunum = smp_processor_id();
+	struct cppc_perf_fb_ctrs *fb_ctrs = val;
 	int ret;
 
-	ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
+	ret = cppc_get_perf_ctrs(cpunum, fb_ctrs);
 	if (ret)
 		return ret;
 
 	udelay(2); /* 2usec delay between sampling */
 
-	ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
+	return cppc_get_perf_ctrs(cpunum, fb_ctrs + 1);
+}
+
+static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
+{
+	struct cppc_perf_fb_ctrs fb_ctrs[2] = {0};
+	struct cppc_cpudata *cpu = all_cpu_data[cpunum];
+	int ret;
+
+	if (cpu_has_amu_feat(cpunum))
+		ret = smp_call_on_cpu(cpunum, cppc_get_perf_ctrs_sample,
+				      fb_ctrs, false);
+	else
+		ret = cppc_get_perf_ctrs_sample(fb_ctrs);
+
 	if (ret)
 		return ret;
 
-	return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
+	return cppc_get_rate_from_fbctrs(cpu, fb_ctrs[0], fb_ctrs[1]);
 }
 
 static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)