From 336e51283ae376835b30b9edfcddd8e7b7615798 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 26 May 2022 17:21:19 +0530 Subject: [PATCH 1/3] cpufreq: Optimize cpufreq_show_cpus() Instead of specially adding a space for each CPU, except the first one, lets add space for each of them and remove it at the end. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 2cad42774164..e24aa5d4bca5 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -843,12 +843,14 @@ ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf) unsigned int cpu; for_each_cpu(cpu, mask) { - if (i) - i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " "); - i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu); + i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u ", cpu); if (i >= (PAGE_SIZE - 5)) break; } + + /* Remove the extra space at the end */ + i--; + i += sprintf(&buf[i], "\n"); return i; } From 9ab9b9d3fb9231cdcfda8e0fb3d9c24a2f95ed26 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 26 May 2022 17:21:21 +0530 Subject: [PATCH 2/3] cpufreq: Drop unnecessary cpus locking from store() This change was introduced long back by commit 4f750c930822 ("cpufreq: Synchronize the cpufreq store_*() routines with CPU hotplug"). Since then, both cpufreq and hotplug core have been reworked and have much better locking in place. The race mentioned in commit 4f750c930822 isn't possible anymore. Drop the unnecessary locking. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index e24aa5d4bca5..73432360e6e9 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -973,21 +973,10 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, if (!fattr->store) return -EIO; - /* - * cpus_read_trylock() is used here to work around a circular lock - * dependency problem with respect to the cpufreq_register_driver(). - */ - if (!cpus_read_trylock()) - return -EBUSY; - - if (cpu_online(policy->cpu)) { - down_write(&policy->rwsem); - if (likely(!policy_is_inactive(policy))) - ret = fattr->store(policy, buf, count); - up_write(&policy->rwsem); - } - - cpus_read_unlock(); + down_write(&policy->rwsem); + if (likely(!policy_is_inactive(policy))) + ret = fattr->store(policy, buf, count); + up_write(&policy->rwsem); return ret; } From d6f895965592d5cd2771860639219964df85d555 Mon Sep 17 00:00:00 2001 From: Tony W Wang-oc Date: Thu, 23 Jun 2022 09:21:26 +0800 Subject: [PATCH 3/3] cpufreq: ACPI: Add Zhaoxin/Centaur turbo boost control interface support Recent Zhaoxin/Centaur CPUs support X86_FEATURE_IDA and the turbo boost can be dynamically enabled or disabled through MSR 0x1a0[38] in the same way as Intel. So add turbo boost control support for these CPUs too. Signed-off-by: Tony W Wang-oc Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/acpi-cpufreq.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index 3d514b82d055..1bb2b90ebb21 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -78,6 +78,8 @@ static bool boost_state(unsigned int cpu) switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: + case X86_VENDOR_CENTAUR: + case X86_VENDOR_ZHAOXIN: rdmsr_on_cpu(cpu, MSR_IA32_MISC_ENABLE, &lo, &hi); msr = lo | ((u64)hi << 32); return !(msr & MSR_IA32_MISC_ENABLE_TURBO_DISABLE); @@ -97,6 +99,8 @@ static int boost_set_msr(bool enable) switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: + case X86_VENDOR_CENTAUR: + case X86_VENDOR_ZHAOXIN: msr_addr = MSR_IA32_MISC_ENABLE; msr_mask = MSR_IA32_MISC_ENABLE_TURBO_DISABLE; break;