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Message-Id: <1305651819-25660-2-git-send-email-mjg@redhat.com>
Date: Tue, 17 May 2011 13:03:36 -0400
From: Matthew Garrett <mjg@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: borislav.petkov@....com, davej@...hat.com, mark.langsdorf@....com,
cpufreq@...r.kernel.org, Matthew Garrett <mjg@...hat.com>
Subject: [PATCH 2/5] acpi-cpufreq: Add support for disabling dynamic overclocking
One feature present in powernow-k8 that isn't present in acpi-cpufreq is
support for enabling or disabling AMD's core performance boost technology.
This patch adds that support to acpi-cpufreq, but also extends it to allow
Intel's dynamic acceleration to be disabled via the same interface. The
sysfs entry retains the cpb name for compatibility purposes.
Signed-off-by: Matthew Garrett <mjg@...hat.com>
---
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 160 ++++++++++++++++++++++++++++
1 files changed, 160 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index f3dd3b1..f55e082 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -79,6 +79,86 @@ static struct acpi_processor_performance __percpu *acpi_perf_data;
static struct cpufreq_driver acpi_cpufreq_driver;
static unsigned int acpi_pstate_strict;
+static bool cpb_enabled, cpb_supported;
+static struct msr __percpu *msrs;
+
+static void _cpb_toggle_msrs(unsigned int cpu, bool t)
+{
+ struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
+
+ get_online_cpus();
+
+ switch (data->cpu_feature) {
+ case SYSTEM_INTEL_MSR_CAPABLE:
+ rdmsr_on_cpus(cpu_online_mask, MSR_IA32_MISC_ENABLE, msrs);
+
+ for_each_cpu(cpu, cpu_online_mask) {
+ struct msr *reg = per_cpu_ptr(msrs, cpu);
+ if (t)
+ reg->q &= ~MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
+ else
+ reg->q |= MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
+ }
+
+ wrmsr_on_cpus(cpu_online_mask, MSR_IA32_MISC_ENABLE, msrs);
+ break;
+ case SYSTEM_AMD_MSR_CAPABLE:
+ rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
+
+ for_each_cpu(cpu, cpu_online_mask) {
+ struct msr *reg = per_cpu_ptr(msrs, cpu);
+ if (t)
+ reg->l &= ~BIT(25);
+ else
+ reg->l |= BIT(25);
+ }
+
+ wrmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
+ break;
+ }
+
+ put_online_cpus();
+}
+
+static void cpb_toggle(unsigned int cpu, bool t)
+{
+ if (t && !cpb_enabled) {
+ cpb_enabled = true;
+ _cpb_toggle_msrs(cpu, t);
+ dprintk("Core Boosting enabled.\n");
+ } else if (!t && cpb_enabled) {
+ cpb_enabled = false;
+ _cpb_toggle_msrs(cpu, t);
+ dprintk("Core Boosting disabled.\n");
+ }
+}
+
+static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
+ size_t count)
+{
+ int ret = -EINVAL;
+ unsigned long val = 0;
+ unsigned int cpu = policy->cpu;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (!ret && (val == 0 || val == 1) && cpb_supported)
+ cpb_toggle(cpu, val);
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf)
+{
+ return sprintf(buf, "%u\n", cpb_enabled);
+}
+
+#define define_one_rw(_name) \
+static struct freq_attr _name = \
+ __ATTR(_name, 0644, show_##_name, store_##_name)
+
+define_one_rw(cpb);
static int check_est_cpu(unsigned int cpuid)
{
@@ -449,6 +529,63 @@ static void free_acpi_perf_data(void)
free_percpu(acpi_perf_data);
}
+static int cpb_notify(struct notifier_block *nb, unsigned long action,
+ void *hcpu)
+{
+ unsigned cpu = (long)hcpu;
+ u32 lo, hi;
+ struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
+ int msr;
+ u64 bit;
+
+ switch (data->cpu_feature) {
+ case SYSTEM_INTEL_MSR_CAPABLE:
+ msr = MSR_IA32_MISC_ENABLE;
+ bit = MSR_IA32_MISC_ENABLE_TURBO_DISABLE;
+ break;
+ case SYSTEM_AMD_MSR_CAPABLE:
+ msr = MSR_K7_HWCR;
+ bit = BIT(25);
+ break;
+ default:
+ return NOTIFY_OK;
+ }
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ if (!cpb_enabled) {
+ rdmsr_on_cpu(cpu, msr, &lo, &hi);
+ if (bit < BIT(32))
+ lo |= bit;
+ else
+ hi |= (bit >> 32);
+ wrmsr_on_cpu(cpu, msr, lo, hi);
+ }
+ break;
+
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ rdmsr_on_cpu(cpu, msr, &lo, &hi);
+ if (bit < BIT(32))
+ lo &= ~bit;
+ else
+ hi &= ~(bit >> 32);
+ wrmsr_on_cpu(cpu, msr, lo, hi);
+ break;
+
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+
+static struct notifier_block cpb_nb = {
+ .notifier_call = cpb_notify,
+};
+
/*
* acpi_cpufreq_early_init - initialize ACPI P-States library
*
@@ -669,6 +806,21 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
if (result)
goto err_freqfree;
+ if (boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA)) {
+ msrs = msrs_alloc();
+
+ if (!msrs) {
+ result = -ENOMEM;
+ goto err_freqfree;
+ }
+
+ cpb_supported = true;
+
+ register_cpu_notifier(&cpb_nb);
+
+ cpb_toggle(0, true);
+ }
+
if (perf->states[0].core_frequency * 1000 != policy->cpuinfo.max_freq)
printk(KERN_WARNING FW_WARN "P-state 0 is not max freq\n");
@@ -752,6 +904,7 @@ static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
static struct freq_attr *acpi_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
+ &cpb,
NULL,
};
@@ -791,6 +944,13 @@ static void __exit acpi_cpufreq_exit(void)
{
dprintk("acpi_cpufreq_exit\n");
+ if (msrs) {
+ unregister_cpu_notifier(&cpb_nb);
+
+ msrs_free(msrs);
+ msrs = NULL;
+ }
+
cpufreq_unregister_driver(&acpi_cpufreq_driver);
free_percpu(acpi_perf_data);
--
1.7.5
--
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