| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <0a1cf7fb-5d2a-4737-bbda-cb866270a523@amd.com>
Date: Thu, 13 Jun 2024 12:55:11 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Perry Yuan <perry.yuan@....com>, gautham.shenoy@....com,
Borislav.Petkov@....com
Cc: rafael.j.wysocki@...el.com, viresh.kumar@...aro.org,
Alexander.Deucher@....com, Xinmei.Huang@....com, Xiaojian.Du@....com,
Li.Meng@....com, linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v11 5/9] cpufreq: amd-pstate: implement cpb_boost sysfs
entry for boost control
On 6/13/2024 02:25, Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@....com>
>
> With this new sysfs entry `cpb_boost`created, user can change CPU boost
> state dynamically under `active`, `guided` and `passive` modes.
> And the highest perf and frequency will also be updated as the boost
> state changing.
>
> 0): check current boost state
> cat /sys/devices/system/cpu/amd_pstate/cpb_boost
>
> 1): disable CPU boost
> sudo bash -c "echo 0 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
>
> 2): enable CPU boost
> sudo bash -c "echo 1 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217618
> Signed-off-by: Perry Yuan <Perry.Yuan@....com>
> ---
> drivers/cpufreq/amd-pstate-ut.c | 2 +-
> drivers/cpufreq/amd-pstate.c | 117 +++++++++++++++++++++++++++++++-
> drivers/cpufreq/amd-pstate.h | 1 +
> 3 files changed, 118 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
> index fc275d41d51e..b528f198f4c3 100644
> --- a/drivers/cpufreq/amd-pstate-ut.c
> +++ b/drivers/cpufreq/amd-pstate-ut.c
> @@ -227,7 +227,7 @@ static void amd_pstate_ut_check_freq(u32 index)
> goto skip_test;
> }
>
> - if (cpudata->boost_supported) {
> + if (amd_pstate_global_params.cpb_boost) {
> if ((policy->max == cpudata->max_freq) ||
> (policy->max == cpudata->nominal_freq))
> amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9f42524074a9..fe7c9d3562c5 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -104,6 +104,7 @@ static bool amd_pstate_prefcore = true;
> static struct quirk_entry *quirks;
> struct amd_pstate_global_params amd_pstate_global_params;
> EXPORT_SYMBOL_GPL(amd_pstate_global_params);
> +static int amd_pstate_cpu_boost(int cpu, bool state);
>
> /*
> * AMD Energy Preference Performance (EPP)
> @@ -738,6 +739,7 @@ static int amd_pstate_boost_set(struct amd_cpudata *cpudata)
> if (amd_pstate_global_params.cpb_supported) {
> current_pstate_driver->boost_enabled = true;
> WRITE_ONCE(cpudata->boost_supported, true);
> + WRITE_ONCE(cpudata->boost_state, true);
> }
>
> amd_pstate_global_params.cpb_boost = amd_pstate_global_params.cpb_supported;
> @@ -745,6 +747,7 @@ static int amd_pstate_boost_set(struct amd_cpudata *cpudata)
>
> exit_err:
> WRITE_ONCE(cpudata->boost_supported, false);
> + WRITE_ONCE(cpudata->boost_state, false);
> current_pstate_driver->boost_enabled = false;
> amd_pstate_global_params.cpb_boost = false;
> return ret;
> @@ -1348,6 +1351,116 @@ static ssize_t prefcore_show(struct device *dev,
> return sysfs_emit(buf, "%s\n", str_enabled_disabled(amd_pstate_prefcore));
> }
>
> +static int amd_pstate_cpu_boost_update(struct cpufreq_policy *policy, bool on)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> + struct cppc_perf_ctrls perf_ctrls;
> + u32 highest_perf, nominal_perf, nominal_freq, max_freq;
> + int ret;
> +
> + if (!policy) {
> + pr_err("policy is null\n");
> + return -ENODATA;
> + }
This is dead code that can't possibly be hit, because there would be a
NULL pointer dereference above for this line:
struct amd_cpudata *cpudata = policy->driver_data;
Furthermore, the caller for this function, amd_pstate_cpu_boost() has
the same check already.
So drop the check here.
> +
> + highest_perf = READ_ONCE(cpudata->highest_perf);
> + nominal_perf = READ_ONCE(cpudata->nominal_perf);
> + nominal_freq = READ_ONCE(cpudata->nominal_freq);
> + max_freq = READ_ONCE(cpudata->max_freq);
> +
> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> + u64 value = READ_ONCE(cpudata->cppc_req_cached);
> +
> + value &= ~GENMASK_ULL(7, 0);
> + value |= on ? highest_perf : nominal_perf;
> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> +
> + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> + } else {
> + perf_ctrls.max_perf = on ? highest_perf : nominal_perf;
> + ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls, 1);
> + if (ret) {
> + cpufreq_cpu_release(policy);
> + pr_debug("failed to set energy perf value (%d)\n", ret);
> + return ret;
> + }
> + }
> +
> + if (on)
> + policy->cpuinfo.max_freq = max_freq;
> + else
> + policy->cpuinfo.max_freq = nominal_freq * 1000;
> +
> + policy->max = policy->cpuinfo.max_freq;
> +
> + if (cppc_state == AMD_PSTATE_PASSIVE) {
> + ret = freq_qos_update_request(&cpudata->req[1], policy->cpuinfo.max_freq);
> + if (ret < 0)
> + pr_debug("Failed to update freq constraint: CPU%d\n", cpudata->cpu);
> + }
> +
> + return ret < 0 ? ret : 0;
> +}
> +
> +static int amd_pstate_cpu_boost(int cpu, bool state)
> +{
> + int ret;
> + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> + struct amd_cpudata *cpudata = policy->driver_data;
> +
> + if (!policy) {
> + pr_err("policy is NULL\n");
> + ret = -ENODATA;
> + goto err_exit;
> + }
> +
> + ret = amd_pstate_cpu_boost_update(policy, state);
> + refresh_frequency_limits(policy);
> + WRITE_ONCE(cpudata->boost_state, state);
> + policy->boost_enabled = state;
> +
> +err_exit:
> + cpufreq_cpu_put(policy);
> + return ret < 0 ? ret : 0;
> +}
> +
> +static ssize_t cpb_boost_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return sysfs_emit(buf, "%u\n", amd_pstate_global_params.cpb_boost);
> +}
> +
> +static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
> + const char *buf, size_t count)
> +{
> + bool new_state;
> + ssize_t ret;
> + int cpu;
> +
> + if (!amd_pstate_global_params.cpb_supported) {
> + pr_err("Boost mode is not supported by this processor or SBIOS\n");
> + return -EINVAL;
> + }
> +
> + ret = kstrtobool(buf, &new_state);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&amd_pstate_driver_lock);
> + for_each_present_cpu(cpu) {
> + ret = amd_pstate_cpu_boost(cpu, new_state);
> + if (ret < 0) {
> + pr_warn("failed to update cpu boost for CPU%d (%zd)\n", cpu, ret);
> + goto err_exit;
> + }
> + }
> + amd_pstate_global_params.cpb_boost = !!new_state;
> +
> +err_exit:
> + mutex_unlock(&amd_pstate_driver_lock);
> + return ret < 0 ? ret : count;
> +}
> +
> cpufreq_freq_attr_ro(amd_pstate_max_freq);
> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>
> @@ -1358,6 +1471,7 @@ cpufreq_freq_attr_rw(energy_performance_preference);
> cpufreq_freq_attr_ro(energy_performance_available_preferences);
> static DEVICE_ATTR_RW(status);
> static DEVICE_ATTR_RO(prefcore);
> +static DEVICE_ATTR_RW(cpb_boost);
>
> static struct freq_attr *amd_pstate_attr[] = {
> &amd_pstate_max_freq,
> @@ -1382,6 +1496,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> static struct attribute *pstate_global_attributes[] = {
> &dev_attr_status.attr,
> &dev_attr_prefcore.attr,
> + &dev_attr_cpb_boost.attr,
> NULL
> };
>
> @@ -1420,7 +1535,7 @@ static int amd_pstate_init_boost(struct cpufreq_policy *policy)
> if (ret)
> return ret;
>
> - policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
> + policy->boost_enabled = READ_ONCE(cpudata->boost_state);
>
> return 0;
> }
> diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
> index 0b75a6267fca..9eba854ab7d3 100644
> --- a/drivers/cpufreq/amd-pstate.h
> +++ b/drivers/cpufreq/amd-pstate.h
> @@ -99,6 +99,7 @@ struct amd_cpudata {
> u32 policy;
> u64 cppc_cap1_cached;
> bool suspended;
> + bool boost_state;
> };
>
> /**
Powered by blists - more mailing lists