// SPDX-License-Identifier: GPL-2.0-only
/*
* Hardware Feedback Interface Driver
*
* Copyright (c) 2021, Intel Corporation.
*
* Authors: Aubrey Li <[email protected]>
* Ricardo Neri <[email protected]>
*
*
* The Hardware Feedback Interface provides a performance and energy efficiency
* capability information for each CPU in the system. Depending on the processor
* model, hardware may periodically update these capabilities as a result of
* changes in the operating conditions (e.g., power limits or thermal
* constraints). On other processor models, there is a single HFI update
* at boot.
*
* This file provides functionality to process HFI updates and relay these
* updates to userspace.
*/
#define pr_fmt(fmt) "intel-hfi: " fmt
#include <linux/bitops.h>
#include <linux/cpufeature.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/math.h>
#include <linux/mutex.h>
#include <linux/percpu-defs.h>
#include <linux/printk.h>
#include <linux/processor.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/suspend.h>
#include <linux/string.h>
#include <linux/syscore_ops.h>
#include <linux/topology.h>
#include <linux/workqueue.h>
#include <asm/msr.h>
#include "intel_hfi.h"
#include "thermal_interrupt.h"
#include "../thermal_netlink.h"
/* Hardware Feedback Interface MSR configuration bits */
#define HW_FEEDBACK_PTR_VALID_BIT BIT(0)
#define HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT BIT(0)
/* CPUID detection and enumeration definitions for HFI */
#define CPUID_HFI_LEAF 6
union hfi_capabilities {
struct {
u8 performance:1;
u8 energy_efficiency:1;
u8 __reserved:6;
} split;
u8 bits;
};
union cpuid6_edx {
struct {
union hfi_capabilities capabilities;
u32 table_pages:4;
u32 __reserved:4;
s32 index:16;
} split;
u32 full;
};
/**
* struct hfi_cpu_data - HFI capabilities per CPU
* @perf_cap: Performance capability
* @ee_cap: Energy efficiency capability
*
* Capabilities of a logical processor in the HFI table. These capabilities are
* unitless.
*/
struct hfi_cpu_data {
u8 perf_cap;
u8 ee_cap;
} __packed;
/**
* struct hfi_hdr - Header of the HFI table
* @perf_updated: Hardware updated performance capabilities
* @ee_updated: Hardware updated energy efficiency capabilities
*
* Properties of the data in an HFI table.
*/
struct hfi_hdr {
u8 perf_updated;
u8 ee_updated;
} __packed;
/**
* struct hfi_instance - Representation of an HFI instance (i.e., a table)
* @local_table: Base of the local copy of the HFI table
* @timestamp: Timestamp of the last update of the local table.
* Located at the base of the local table.
* @hdr: Base address of the header of the local table
* @data: Base address of the data of the local table
* @cpus: CPUs represented in this HFI table instance
* @hw_table: Pointer to the HFI table of this instance
* @update_work: Delayed work to process HFI updates
* @table_lock: Lock to protect acceses to the table of this instance
* @event_lock: Lock to process HFI interrupts
*
* A set of parameters to parse and navigate a specific HFI table.
*/
struct hfi_instance {
union {
void *local_table;
u64 *timestamp;
};
void *hdr;
void *data;
cpumask_var_t cpus;
void *hw_table;
struct delayed_work update_work;
raw_spinlock_t table_lock;
raw_spinlock_t event_lock;
};
/**
* struct hfi_features - Supported HFI features
* @nr_table_pages: Size of the HFI table in 4KB pages
* @cpu_stride: Stride size to locate the capability data of a logical
* processor within the table (i.e., row stride)
* @hdr_size: Size of the table header
*
* Parameters and supported features that are common to all HFI instances
*/
struct hfi_features {
size_t nr_table_pages;
unsigned int cpu_stride;
unsigned int hdr_size;
};
/**
* struct hfi_cpu_info - Per-CPU attributes to consume HFI data
* @index: Row of this CPU in its HFI table
* @hfi_instance: Attributes of the HFI table to which this CPU belongs
*
* Parameters to link a logical processor to an HFI table and a row within it.
*/
struct hfi_cpu_info {
s16 index;
struct hfi_instance *hfi_instance;
};
static DEFINE_PER_CPU(struct hfi_cpu_info, hfi_cpu_info) = { .index = -1 };
static int max_hfi_instances;
static int hfi_clients_nr;
static struct hfi_instance *hfi_instances;
static struct hfi_features hfi_features;
static DEFINE_MUTEX(hfi_instance_lock);
static struct workqueue_struct *hfi_updates_wq;
#define HFI_UPDATE_DELAY_MS 100
#define HFI_THERMNL_CAPS_PER_EVENT 64
static void get_hfi_caps(struct hfi_instance *hfi_instance,
struct thermal_genl_cpu_caps *cpu_caps)
{
int cpu, i = 0;
raw_spin_lock_irq(&hfi_instance->table_lock);
for_each_cpu(cpu, hfi_instance->cpus) {
struct hfi_cpu_data *caps;
s16 index;
index = per_cpu(hfi_cpu_info, cpu).index;
caps = hfi_instance->data + index * hfi_features.cpu_stride;
cpu_caps[i].cpu = cpu;
/*
* Scale performance and energy efficiency to
* the [0, 1023] interval that thermal netlink uses.
*/
cpu_caps[i].performance = caps->perf_cap << 2;
cpu_caps[i].efficiency = caps->ee_cap << 2;
++i;
}
raw_spin_unlock_irq(&hfi_instance->table_lock);
}
/*
* Call update_capabilities() when there are changes in the HFI table.
*/
static void update_capabilities(struct hfi_instance *hfi_instance)
{
struct thermal_genl_cpu_caps *cpu_caps;
int i = 0, cpu_count;
/* CPUs may come online/offline while processing an HFI update. */
mutex_lock(&hfi_instance_lock);
cpu_count = cpumask_weight(hfi_instance->cpus);
/* No CPUs to report in this hfi_instance. */
if (!cpu_count)
goto out;
cpu_caps = kcalloc(cpu_count, sizeof(*cpu_caps), GFP_KERNEL);
if (!cpu_caps)
goto out;
get_hfi_caps(hfi_instance, cpu_caps);
if (cpu_count < HFI_THERMNL_CAPS_PER_EVENT)
goto last_cmd;
/* Process complete chunks of HFI_THERMNL_CAPS_PER_EVENT capabilities. */
for (i = 0;
(i + HFI_THERMNL_CAPS_PER_EVENT) <= cpu_count;
i += HFI_THERMNL_CAPS_PER_EVENT)
thermal_genl_cpu_capability_event(HFI_THERMNL_CAPS_PER_EVENT,
&cpu_caps[i]);
cpu_count = cpu_count - i;
last_cmd:
/* Process the remaining capabilities if any. */
if (cpu_count)
thermal_genl_cpu_capability_event(cpu_count, &cpu_caps[i]);
kfree(cpu_caps);
out:
mutex_unlock(&hfi_instance_lock);
}
static void hfi_update_work_fn(struct work_struct *work)
{
struct hfi_instance *hfi_instance;
hfi_instance = container_of(to_delayed_work(work), struct hfi_instance,
update_work);
update_capabilities(hfi_instance);
}
void intel_hfi_process_event(__u64 pkg_therm_status_msr_val)
{
struct hfi_instance *hfi_instance;
int cpu = smp_processor_id();
struct hfi_cpu_info *info;
u64 new_timestamp, msr, hfi;
if (!pkg_therm_status_msr_val)
return;
info = &per_cpu(hfi_cpu_info, cpu);
if (!info)
return;
/*
* A CPU is linked to its HFI instance before the thermal vector in the
* local APIC is unmasked. Hence, info->hfi_instance cannot be NULL
* when receiving an HFI event.
*/
hfi_instance = info->hfi_instance;
if (unlikely(!hfi_instance)) {
pr_debug("Received event on CPU %d but instance was null", cpu);
return;
}
/*
* On most systems, all CPUs in the package receive a package-level
* thermal interrupt when there is an HFI update. It is sufficient to
* let a single CPU to acknowledge the update and queue work to
* process it. The remaining CPUs can resume their work.
*/
if (!raw_spin_trylock(&hfi_instance->event_lock))
return;
rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr);
hfi = msr & PACKAGE_THERM_STATUS_HFI_UPDATED;
if (!hfi) {
raw_spin_unlock(&hfi_instance->event_lock);
return;
}
/*
* Ack duplicate update. Since there is an active HFI
* status from HW, it must be a new event, not a case
* where a lagging CPU entered the locked region.
*/
new_timestamp = *(u64 *)hfi_instance->hw_table;
if (*hfi_instance->timestamp == new_timestamp) {
thermal_clear_package_intr_status(PACKAGE_LEVEL, PACKAGE_THERM_STATUS_HFI_UPDATED);
raw_spin_unlock(&hfi_instance->event_lock);
return;
}
raw_spin_lock(&hfi_instance->table_lock);
/*
* Copy the updated table into our local copy. This includes the new
* timestamp.
*/
memcpy(hfi_instance->local_table, hfi_instance->hw_table,
hfi_features.nr_table_pages << PAGE_SHIFT);
/*
* Let hardware know that we are done reading the HFI table and it is
* free to update it again.
*/
thermal_clear_package_intr_status(PACKAGE_LEVEL, PACKAGE_THERM_STATUS_HFI_UPDATED);
raw_spin_unlock(&hfi_instance->table_lock);
raw_spin_unlock(&hfi_instance->event_lock);
queue_delayed_work(hfi_updates_wq, &hfi_instance->update_work,
msecs_to_jiffies(HFI_UPDATE_DELAY_MS));
}
static void init_hfi_cpu_index(struct hfi_cpu_info *info)
{
union cpuid6_edx edx;
/* Do not re-read @cpu's index if it has already been initialized. */
if (info->index > -1)
return;
edx.full = cpuid_edx(CPUID_HFI_LEAF);
info->index = edx.split.index;
}
/*
* The format of the HFI table depends on the number of capabilities that the
* hardware supports. Keep a data structure to navigate the table.
*/
static void init_hfi_instance(struct hfi_instance *hfi_instance)
{
/* The HFI header is below the time-stamp. */
hfi_instance->hdr = hfi_instance->local_table +
sizeof(*hfi_instance->timestamp);
/* The HFI data starts below the header. */
hfi_instance->data = hfi_instance->hdr + hfi_features.hdr_size;
}
/* Caller must hold hfi_instance_lock. */
static void hfi_enable(void)
{
u64 msr_val;
rdmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
msr_val |= HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT;
wrmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
}
static void hfi_set_hw_table(struct hfi_instance *hfi_instance)
{
phys_addr_t hw_table_pa;
u64 msr_val;
hw_table_pa = virt_to_phys(hfi_instance->hw_table);
msr_val = hw_table_pa | HW_FEEDBACK_PTR_VALID_BIT;
wrmsrl(MSR_IA32_HW_FEEDBACK_PTR, msr_val);
}
/* Caller must hold hfi_instance_lock. */
static void hfi_disable(void)
{
u64 msr_val;
int i;
rdmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
msr_val &= ~HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT;
wrmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
/*
* Wait for hardware to acknowledge the disabling of HFI. Some
* processors may not do it. Wait for ~2ms. This is a reasonable
* time for hardware to complete any pending actions on the HFI
* memory.
*/
for (i = 0; i < 2000; i++) {
rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr_val);
if (msr_val & PACKAGE_THERM_STATUS_HFI_UPDATED)
break;
udelay(1);
cpu_relax();
}
}
/**
* intel_hfi_online() - Enable HFI on @cpu
* @cpu: CPU in which the HFI will be enabled
*
* Enable the HFI to be used in @cpu. The HFI is enabled at the package
* level. The first CPU in the package to come online does the full HFI
* initialization. Subsequent CPUs will just link themselves to the HFI
* instance of their package.
*
* This function is called before enabling the thermal vector in the local APIC
* in order to ensure that @cpu has an associated HFI instance when it receives
* an HFI event.
*/
void intel_hfi_online(unsigned int cpu)
{
struct hfi_instance *hfi_instance;
struct hfi_cpu_info *info;
u16 pkg_id;
/* Nothing to do if hfi_instances are missing. */
if (!hfi_instances)
return;
/*
* Link @cpu to the HFI instance of its package. It does not
* matter whether the instance has been initialized.
*/
info = &per_cpu(hfi_cpu_info, cpu);
pkg_id = topology_logical_package_id(cpu);
hfi_instance = info->hfi_instance;
if (!hfi_instance) {
if (pkg_id >= max_hfi_instances)
return;
hfi_instance = &hfi_instances[pkg_id];
info->hfi_instance = hfi_instance;
}
init_hfi_cpu_index(info);
/*
* Now check if the HFI instance of the package of @cpu has been
* initialized (by checking its header). In such case, all we have to
* do is to add @cpu to this instance's cpumask and enable the instance
* if needed.
*/
mutex_lock(&hfi_instance_lock);
if (hfi_instance->hdr)
goto enable;
/*
* Hardware is programmed with the physical address of the first page
* frame of the table. Hence, the allocated memory must be page-aligned.
*
* Some processors do not forget the initial address of the HFI table
* even after having been reprogrammed. Keep using the same pages. Do
* not free them.
*/
hfi_instance->hw_table = alloc_pages_exact(hfi_features.nr_table_pages,
GFP_KERNEL | __GFP_ZERO);
if (!hfi_instance->hw_table)
goto unlock;
/*
* Allocate memory to keep a local copy of the table that
* hardware generates.
*/
hfi_instance->local_table = kzalloc(hfi_features.nr_table_pages << PAGE_SHIFT,
GFP_KERNEL);
if (!hfi_instance->local_table)
goto free_hw_table;
init_hfi_instance(hfi_instance);
INIT_DELAYED_WORK(&hfi_instance->update_work, hfi_update_work_fn);
raw_spin_lock_init(&hfi_instance->table_lock);
raw_spin_lock_init(&hfi_instance->event_lock);
enable:
cpumask_set_cpu(cpu, hfi_instance->cpus);
/*
* Enable this HFI instance if this is its first online CPU and
* there are user-space clients of thermal events.
*/
if (cpumask_weight(hfi_instance->cpus) == 1 && hfi_clients_nr > 0) {
hfi_set_hw_table(hfi_instance);
hfi_enable();
}
unlock:
mutex_unlock(&hfi_instance_lock);
return;
free_hw_table:
free_pages_exact(hfi_instance->hw_table, hfi_features.nr_table_pages);
goto unlock;
}
/**
* intel_hfi_offline() - Disable HFI on @cpu
* @cpu: CPU in which the HFI will be disabled
*
* Remove @cpu from those covered by its HFI instance.
*
* On some processors, hardware remembers previous programming settings even
* after being reprogrammed. Thus, keep HFI enabled even if all CPUs in the
* package of @cpu are offline. See note in intel_hfi_online().
*/
void intel_hfi_offline(unsigned int cpu)
{
struct hfi_cpu_info *info = &per_cpu(hfi_cpu_info, cpu);
struct hfi_instance *hfi_instance;
/*
* Check if @cpu as an associated, initialized (i.e., with a non-NULL
* header). Also, HFI instances are only initialized if X86_FEATURE_HFI
* is present.
*/
hfi_instance = info->hfi_instance;
if (!hfi_instance)
return;
if (!hfi_instance->hdr)
return;
mutex_lock(&hfi_instance_lock);
cpumask_clear_cpu(cpu, hfi_instance->cpus);
if (!cpumask_weight(hfi_instance->cpus))
hfi_disable();
mutex_unlock(&hfi_instance_lock);
}
static __init int hfi_parse_features(void)
{
unsigned int nr_capabilities;
union cpuid6_edx edx;
if (!boot_cpu_has(X86_FEATURE_HFI))
return -ENODEV;
/*
* If we are here we know that CPUID_HFI_LEAF exists. Parse the
* supported capabilities and the size of the HFI table.
*/
edx.full = cpuid_edx(CPUID_HFI_LEAF);
if (!edx.split.capabilities.split.performance) {
pr_debug("Performance reporting not supported! Not using HFI\n");
return -ENODEV;
}
/*
* The number of supported capabilities determines the number of
* columns in the HFI table. Exclude the reserved bits.
*/
edx.split.capabilities.split.__reserved = 0;
nr_capabilities = hweight8(edx.split.capabilities.bits);
/* The number of 4KB pages required by the table */
hfi_features.nr_table_pages = edx.split.table_pages + 1;
/*
* The header contains change indications for each supported feature.
* The size of the table header is rounded up to be a multiple of 8
* bytes.
*/
hfi_features.hdr_size = DIV_ROUND_UP(nr_capabilities, 8) * 8;
/*
* Data of each logical processor is also rounded up to be a multiple
* of 8 bytes.
*/
hfi_features.cpu_stride = DIV_ROUND_UP(nr_capabilities, 8) * 8;
return 0;
}
/*
* If concurrency is not prevented by other means, the HFI enable/disable
* routines must be called under hfi_instance_lock."
*/
static void hfi_enable_instance(void *ptr)
{
hfi_set_hw_table(ptr);
hfi_enable();
}
static void hfi_disable_instance(void *ptr)
{
hfi_disable();
}
static void hfi_syscore_resume(void)
{
/* This code runs only on the boot CPU. */
struct hfi_cpu_info *info = &per_cpu(hfi_cpu_info, 0);
struct hfi_instance *hfi_instance = info->hfi_instance;
/* No locking needed. There is no concurrency with CPU online. */
if (hfi_clients_nr > 0)
hfi_enable_instance(hfi_instance);
}
static int hfi_syscore_suspend(void)
{
/* No locking needed. There is no concurrency with CPU offline. */
hfi_disable();
return 0;
}
static struct syscore_ops hfi_pm_ops = {
.resume = hfi_syscore_resume,
.suspend = hfi_syscore_suspend,
};
static int hfi_thermal_notify(struct notifier_block *nb, unsigned long state,
void *_notify)
{
struct thermal_genl_notify *notify = _notify;
struct hfi_instance *hfi_instance;
smp_call_func_t func = NULL;
unsigned int cpu;
int i;
if (notify->mcgrp != THERMAL_GENL_EVENT_GROUP)
return NOTIFY_DONE;
if (state != THERMAL_NOTIFY_BIND && state != THERMAL_NOTIFY_UNBIND)
return NOTIFY_DONE;
mutex_lock(&hfi_instance_lock);
switch (state) {
case THERMAL_NOTIFY_BIND:
if (++hfi_clients_nr == 1)
func = hfi_enable_instance;
break;
case THERMAL_NOTIFY_UNBIND:
if (--hfi_clients_nr == 0)
func = hfi_disable_instance;
break;
}
if (!func)
goto out;
for (i = 0; i < max_hfi_instances; i++) {
hfi_instance = &hfi_instances[i];
if (cpumask_empty(hfi_instance->cpus))
continue;
cpu = cpumask_any(hfi_instance->cpus);
smp_call_function_single(cpu, func, hfi_instance, true);
}
out:
mutex_unlock(&hfi_instance_lock);
return NOTIFY_OK;
}
static struct notifier_block hfi_thermal_nb = {
.notifier_call = hfi_thermal_notify,
};
void __init intel_hfi_init(void)
{
struct hfi_instance *hfi_instance;
int i, j;
if (hfi_parse_features())
return;
/*
* Note: HFI resources are managed at the physical package scope.
* There could be platforms that enumerate packages as Linux dies.
* Special handling would be needed if this happens on an HFI-capable
* platform.
*/
max_hfi_instances = topology_max_packages();
/*
* This allocation may fail. CPU hotplug callbacks must check
* for a null pointer.
*/
hfi_instances = kcalloc(max_hfi_instances, sizeof(*hfi_instances),
GFP_KERNEL);
if (!hfi_instances)
return;
for (i = 0; i < max_hfi_instances; i++) {
hfi_instance = &hfi_instances[i];
if (!zalloc_cpumask_var(&hfi_instance->cpus, GFP_KERNEL))
goto err_nomem;
}
hfi_updates_wq = create_singlethread_workqueue("hfi-updates");
if (!hfi_updates_wq)
goto err_nomem;
/*
* Both thermal core and Intel HFI can not be build as modules.
* As kernel build-in drivers they are initialized before user-space
* starts, hence we can not miss BIND/UNBIND events when applications
* add/remove thermal multicast group to/from a netlink socket.
*/
if (thermal_genl_register_notifier(&hfi_thermal_nb))
goto err_nl_notif;
register_syscore_ops(&hfi_pm_ops);
return;
err_nl_notif:
destroy_workqueue(hfi_updates_wq);
err_nomem:
for (j = 0; j < i; ++j) {
hfi_instance = &hfi_instances[j];
free_cpumask_var(hfi_instance->cpus);
}
kfree(hfi_instances);
hfi_instances = NULL;
}
Codebase Browser
linux