xen-acpi-processor.c

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/*
 * Copyright 2012 by Oracle Inc
 * Author: Konrad Rzeszutek Wilk <[email protected]>
 *
 * This code borrows ideas from https://lkml.org/lkml/2011/11/30/249
 * so many thanks go to Kevin Tian <[email protected]>
 * and Yu Ke <[email protected]>.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#include <linux/cpumask.h>
#include <linux/cpufreq.h>
#include <linux/freezer.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <acpi/processor.h>

#include <xen/xen.h>
#include <xen/interface/platform.h>
#include <asm/xen/hypercall.h>

#define DRV_NAME "xen-acpi-processor: "

static int no_hypercall;
MODULE_PARM_DESC(off, "Inhibit the hypercall.");
module_param_named(off, no_hypercall, int, 0400);

/*
 * Note: Do not convert the acpi_id* below to cpumask_var_t or use cpumask_bit
 * - as those shrink to nr_cpu_bits (which is dependent on possible_cpu), which
 * can be less than what we want to put in. Instead use the 'nr_acpi_bits'
 * which is dynamically computed based on the MADT or x2APIC table.
 */
static unsigned int nr_acpi_bits;
/* Mutex to protect the acpi_ids_done - for CPU hotplug use. */
static DEFINE_MUTEX(acpi_ids_mutex);
/* Which ACPI ID we have processed from 'struct acpi_processor'. */
static unsigned long *acpi_ids_done;
/* Which ACPI ID exist in the SSDT/DSDT processor definitions. */
static unsigned long __initdata *acpi_id_present;
/* And if there is an _CST definition (or a PBLK) for the ACPI IDs */
static unsigned long __initdata *acpi_id_cst_present;

static int push_cxx_to_hypervisor(struct acpi_processor *_pr)
{
    struct xen_platform_op op = {
        .cmd            = XENPF_set_processor_pminfo,
        .interface_version  = XENPF_INTERFACE_VERSION,
        .u.set_pminfo.id    = _pr->acpi_id,
        .u.set_pminfo.type  = XEN_PM_CX,
    };
    struct xen_processor_cx *dst_cx, *dst_cx_states = NULL;
    struct acpi_processor_cx *cx;
    unsigned int i, ok;
    int ret = 0;

    dst_cx_states = kcalloc(_pr->power.count,
                sizeof(struct xen_processor_cx), GFP_KERNEL);
    if (!dst_cx_states)
        return -ENOMEM;

    for (ok = 0, i = 1; i <= _pr->power.count; i++) {
        cx = &_pr->power.states[i];
        if (!cx->valid)
            continue;

        dst_cx = &(dst_cx_states[ok++]);

        dst_cx->reg.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
        if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
            dst_cx->reg.bit_width = 8;
            dst_cx->reg.bit_offset = 0;
            dst_cx->reg.access_size = 1;
        } else {
            dst_cx->reg.space_id = ACPI_ADR_SPACE_FIXED_HARDWARE;
            if (cx->entry_method == ACPI_CSTATE_FFH) {
                /* NATIVE_CSTATE_BEYOND_HALT */
                dst_cx->reg.bit_offset = 2;
                dst_cx->reg.bit_width = 1; /* VENDOR_INTEL */
            }
            dst_cx->reg.access_size = 0;
        }
        dst_cx->reg.address = cx->address;

        dst_cx->type = cx->type;
        dst_cx->latency = cx->latency;

        dst_cx->dpcnt = 0;
        set_xen_guest_handle(dst_cx->dp, NULL);
    }
    if (!ok) {
        pr_debug(DRV_NAME "No _Cx for ACPI CPU %u\n", _pr->acpi_id);
        kfree(dst_cx_states);
        return -EINVAL;
    }
    op.u.set_pminfo.power.count = ok;
    op.u.set_pminfo.power.flags.bm_control = _pr->flags.bm_control;
    op.u.set_pminfo.power.flags.bm_check = _pr->flags.bm_check;
    op.u.set_pminfo.power.flags.has_cst = _pr->flags.has_cst;
    op.u.set_pminfo.power.flags.power_setup_done =
        _pr->flags.power_setup_done;

    set_xen_guest_handle(op.u.set_pminfo.power.states, dst_cx_states);

    if (!no_hypercall)
        ret = HYPERVISOR_dom0_op(&op);

    if (!ret) {
        pr_debug("ACPI CPU%u - C-states uploaded.\n", _pr->acpi_id);
        for (i = 1; i <= _pr->power.count; i++) {
            cx = &_pr->power.states[i];
            if (!cx->valid)
                continue;
            pr_debug("     C%d: %s %d uS\n",
                 cx->type, cx->desc, (u32)cx->latency);
        }
    } else if (ret != -EINVAL)
        /* EINVAL means the ACPI ID is incorrect - meaning the ACPI
         * table is referencing a non-existing CPU - which can happen
         * with broken ACPI tables. */
        pr_err(DRV_NAME "(CX): Hypervisor error (%d) for ACPI CPU%u\n",
               ret, _pr->acpi_id);

    kfree(dst_cx_states);

    return ret;
}
static struct xen_processor_px *
xen_copy_pss_data(struct acpi_processor *_pr,
          struct xen_processor_performance *dst_perf)
{
    struct xen_processor_px *dst_states = NULL;
    unsigned int i;

    BUILD_BUG_ON(sizeof(struct xen_processor_px) !=
             sizeof(struct acpi_processor_px));

    dst_states = kcalloc(_pr->performance->state_count,
                 sizeof(struct xen_processor_px), GFP_KERNEL);
    if (!dst_states)
        return ERR_PTR(-ENOMEM);

    dst_perf->state_count = _pr->performance->state_count;
    for (i = 0; i < _pr->performance->state_count; i++) {
        /* Fortunatly for us, they are both the same size */
        memcpy(&(dst_states[i]), &(_pr->performance->states[i]),
               sizeof(struct acpi_processor_px));
    }
    return dst_states;
}
static int xen_copy_psd_data(struct acpi_processor *_pr,
                 struct xen_processor_performance *dst)
{
    struct acpi_psd_package *pdomain;

    BUILD_BUG_ON(sizeof(struct xen_psd_package) !=
             sizeof(struct acpi_psd_package));

    /* This information is enumerated only if acpi_processor_preregister_performance
     * has been called.
     */
    dst->shared_type = _pr->performance->shared_type;

    pdomain = &(_pr->performance->domain_info);

    /* 'acpi_processor_preregister_performance' does not parse if the
     * num_processors <= 1, but Xen still requires it. Do it manually here.
     */
    if (pdomain->num_processors <= 1) {
        if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
            dst->shared_type = CPUFREQ_SHARED_TYPE_ALL;
        else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
            dst->shared_type = CPUFREQ_SHARED_TYPE_HW;
        else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
            dst->shared_type = CPUFREQ_SHARED_TYPE_ANY;

    }
    memcpy(&(dst->domain_info), pdomain, sizeof(struct acpi_psd_package));
    return 0;
}
static int xen_copy_pct_data(struct acpi_pct_register *pct,
                 struct xen_pct_register *dst_pct)
{
    /* It would be nice if you could just do 'memcpy(pct, dst_pct') but
     * sadly the Xen structure did not have the proper padding so the
     * descriptor field takes two (dst_pct) bytes instead of one (pct).
     */
    dst_pct->descriptor = pct->descriptor;
    dst_pct->length = pct->length;
    dst_pct->space_id = pct->space_id;
    dst_pct->bit_width = pct->bit_width;
    dst_pct->bit_offset = pct->bit_offset;
    dst_pct->reserved = pct->reserved;
    dst_pct->address = pct->address;
    return 0;
}
static int push_pxx_to_hypervisor(struct acpi_processor *_pr)
{
    int ret = 0;
    struct xen_platform_op op = {
        .cmd            = XENPF_set_processor_pminfo,
        .interface_version  = XENPF_INTERFACE_VERSION,
        .u.set_pminfo.id    = _pr->acpi_id,
        .u.set_pminfo.type  = XEN_PM_PX,
    };
    struct xen_processor_performance *dst_perf;
    struct xen_processor_px *dst_states = NULL;

    dst_perf = &op.u.set_pminfo.perf;

    dst_perf->platform_limit = _pr->performance_platform_limit;
    dst_perf->flags |= XEN_PX_PPC;
    xen_copy_pct_data(&(_pr->performance->control_register),
              &dst_perf->control_register);
    xen_copy_pct_data(&(_pr->performance->status_register),
              &dst_perf->status_register);
    dst_perf->flags |= XEN_PX_PCT;
    dst_states = xen_copy_pss_data(_pr, dst_perf);
    if (!IS_ERR_OR_NULL(dst_states)) {
        set_xen_guest_handle(dst_perf->states, dst_states);
        dst_perf->flags |= XEN_PX_PSS;
    }
    if (!xen_copy_psd_data(_pr, dst_perf))
        dst_perf->flags |= XEN_PX_PSD;

    if (dst_perf->flags != (XEN_PX_PSD | XEN_PX_PSS | XEN_PX_PCT | XEN_PX_PPC)) {
        pr_warn(DRV_NAME "ACPI CPU%u missing some P-state data (%x), skipping.\n",
            _pr->acpi_id, dst_perf->flags);
        ret = -ENODEV;
        goto err_free;
    }

    if (!no_hypercall)
        ret = HYPERVISOR_dom0_op(&op);

    if (!ret) {
        struct acpi_processor_performance *perf;
        unsigned int i;

        perf = _pr->performance;
        pr_debug("ACPI CPU%u - P-states uploaded.\n", _pr->acpi_id);
        for (i = 0; i < perf->state_count; i++) {
            pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",
            (i == perf->state ? '*' : ' '), i,
            (u32) perf->states[i].core_frequency,
            (u32) perf->states[i].power,
            (u32) perf->states[i].transition_latency);
        }
    } else if (ret != -EINVAL)
        /* EINVAL means the ACPI ID is incorrect - meaning the ACPI
         * table is referencing a non-existing CPU - which can happen
         * with broken ACPI tables. */
        pr_warn(DRV_NAME "(_PXX): Hypervisor error (%d) for ACPI CPU%u\n",
               ret, _pr->acpi_id);
err_free:
    if (!IS_ERR_OR_NULL(dst_states))
        kfree(dst_states);

    return ret;
}
static int upload_pm_data(struct acpi_processor *_pr)
{
    int err = 0;

    mutex_lock(&acpi_ids_mutex);
    if (__test_and_set_bit(_pr->acpi_id, acpi_ids_done)) {
        mutex_unlock(&acpi_ids_mutex);
        return -EBUSY;
    }
    if (_pr->flags.power)
        err = push_cxx_to_hypervisor(_pr);

    if (_pr->performance && _pr->performance->states)
        err |= push_pxx_to_hypervisor(_pr);

    mutex_unlock(&acpi_ids_mutex);
    return err;
}
static unsigned int __init get_max_acpi_id(void)
{
    struct xenpf_pcpuinfo *info;
    struct xen_platform_op op = {
        .cmd = XENPF_get_cpuinfo,
        .interface_version = XENPF_INTERFACE_VERSION,
    };
    int ret = 0;
    unsigned int i, last_cpu, max_acpi_id = 0;

    info = &op.u.pcpu_info;
    info->xen_cpuid = 0;

    ret = HYPERVISOR_dom0_op(&op);
    if (ret)
        return NR_CPUS;

    /* The max_present is the same irregardless of the xen_cpuid */
    last_cpu = op.u.pcpu_info.max_present;
    for (i = 0; i <= last_cpu; i++) {
        info->xen_cpuid = i;
        ret = HYPERVISOR_dom0_op(&op);
        if (ret)
            continue;
        max_acpi_id = max(info->acpi_id, max_acpi_id);
    }
    max_acpi_id *= 2; /* Slack for CPU hotplug support. */
    pr_debug(DRV_NAME "Max ACPI ID: %u\n", max_acpi_id);
    return max_acpi_id;
}
/*
 * The read_acpi_id and check_acpi_ids are there to support the Xen
 * oddity of virtual CPUs != physical CPUs in the initial domain.
 * The user can supply 'xen_max_vcpus=X' on the Xen hypervisor line
 * which will band the amount of CPUs the initial domain can see.
 * In general that is OK, except it plays havoc with any of the
 * for_each_[present|online]_cpu macros which are banded to the virtual
 * CPU amount.
 */
static acpi_status __init
read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
{
    u32 acpi_id;
    acpi_status status;
    acpi_object_type acpi_type;
    unsigned long long tmp;
    union acpi_object object = { 0 };
    struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
    acpi_io_address pblk = 0;

    status = acpi_get_type(handle, &acpi_type);
    if (ACPI_FAILURE(status))
        return AE_OK;

    switch (acpi_type) {
    case ACPI_TYPE_PROCESSOR:
        status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
        if (ACPI_FAILURE(status))
            return AE_OK;
        acpi_id = object.processor.proc_id;
        pblk = object.processor.pblk_address;
        break;
    case ACPI_TYPE_DEVICE:
        status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
        if (ACPI_FAILURE(status))
            return AE_OK;
        acpi_id = tmp;
        break;
    default:
        return AE_OK;
    }
    /* There are more ACPI Processor objects than in x2APIC or MADT.
     * This can happen with incorrect ACPI SSDT declerations. */
    if (acpi_id > nr_acpi_bits) {
        pr_debug(DRV_NAME "We only have %u, trying to set %u\n",
             nr_acpi_bits, acpi_id);
        return AE_OK;
    }
    /* OK, There is a ACPI Processor object */
    __set_bit(acpi_id, acpi_id_present);

    pr_debug(DRV_NAME "ACPI CPU%u w/ PBLK:0x%lx\n", acpi_id,
         (unsigned long)pblk);

    status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
    if (ACPI_FAILURE(status)) {
        if (!pblk)
            return AE_OK;
    }
    /* .. and it has a C-state */
    __set_bit(acpi_id, acpi_id_cst_present);

    return AE_OK;
}
static int __init check_acpi_ids(struct acpi_processor *pr_backup)
{

    if (!pr_backup)
        return -ENODEV;

    /* All online CPUs have been processed at this stage. Now verify
     * whether in fact "online CPUs" == physical CPUs.
     */
    acpi_id_present = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
    if (!acpi_id_present)
        return -ENOMEM;

    acpi_id_cst_present = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
    if (!acpi_id_cst_present) {
        kfree(acpi_id_present);
        return -ENOMEM;
    }

    acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
                ACPI_UINT32_MAX,
                read_acpi_id, NULL, NULL, NULL);
    acpi_get_devices("ACPI0007", read_acpi_id, NULL, NULL);

    if (!bitmap_equal(acpi_id_present, acpi_ids_done, nr_acpi_bits)) {
        unsigned int i;
        for_each_set_bit(i, acpi_id_present, nr_acpi_bits) {
            pr_backup->acpi_id = i;
            /* Mask out C-states if there are no _CST or PBLK */
            pr_backup->flags.power = test_bit(i, acpi_id_cst_present);
            (void)upload_pm_data(pr_backup);
        }
    }
    kfree(acpi_id_present);
    acpi_id_present = NULL;
    kfree(acpi_id_cst_present);
    acpi_id_cst_present = NULL;
    return 0;
}
static int __init check_prereq(void)
{
    struct cpuinfo_x86 *c = &cpu_data(0);

    if (!xen_initial_domain())
        return -ENODEV;

    if (!acpi_gbl_FADT.smi_command)
        return -ENODEV;

    if (c->x86_vendor == X86_VENDOR_INTEL) {
        if (!cpu_has(c, X86_FEATURE_EST))
            return -ENODEV;

        return 0;
    }
    if (c->x86_vendor == X86_VENDOR_AMD) {
        /* Copied from powernow-k8.h, can't include ../cpufreq/powernow
         * as we get compile warnings for the static functions.
         */
#define CPUID_FREQ_VOLT_CAPABILITIES    0x80000007
#define USE_HW_PSTATE                   0x00000080
        u32 eax, ebx, ecx, edx;
        cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
        if ((edx & USE_HW_PSTATE) != USE_HW_PSTATE)
            return -ENODEV;
        return 0;
    }
    return -ENODEV;
}
/* acpi_perf_data is a pointer to percpu data. */
static struct acpi_processor_performance __percpu *acpi_perf_data;

static void free_acpi_perf_data(void)
{
    unsigned int i;

    /* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
    for_each_possible_cpu(i)
        free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
                 ->shared_cpu_map);
    free_percpu(acpi_perf_data);
}

static int __init xen_acpi_processor_init(void)
{
    struct acpi_processor *pr_backup = NULL;
    unsigned int i;
    int rc = check_prereq();

    if (rc)
        return rc;

    nr_acpi_bits = get_max_acpi_id() + 1;
    acpi_ids_done = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
    if (!acpi_ids_done)
        return -ENOMEM;

    acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
    if (!acpi_perf_data) {
        pr_debug(DRV_NAME "Memory allocation error for acpi_perf_data.\n");
        kfree(acpi_ids_done);
        return -ENOMEM;
    }
    for_each_possible_cpu(i) {
        if (!zalloc_cpumask_var_node(
            &per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
            GFP_KERNEL, cpu_to_node(i))) {
            rc = -ENOMEM;
            goto err_out;
        }
    }

    /* Do initialization in ACPI core. It is OK to fail here. */
    (void)acpi_processor_preregister_performance(acpi_perf_data);

    for_each_possible_cpu(i) {
        struct acpi_processor_performance *perf;

        perf = per_cpu_ptr(acpi_perf_data, i);
        rc = acpi_processor_register_performance(perf, i);
        if (rc)
            goto err_out;
    }
    rc = acpi_processor_notify_smm(THIS_MODULE);
    if (rc)
        goto err_unregister;

    for_each_possible_cpu(i) {
        struct acpi_processor *_pr;
        _pr = per_cpu(processors, i /* APIC ID */);
        if (!_pr)
            continue;

        if (!pr_backup) {
            pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
            if (pr_backup)
                memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
        }
        (void)upload_pm_data(_pr);
    }
    rc = check_acpi_ids(pr_backup);

    kfree(pr_backup);
    pr_backup = NULL;

    if (rc)
        goto err_unregister;

    return 0;
err_unregister:
    for_each_possible_cpu(i) {
        struct acpi_processor_performance *perf;
        perf = per_cpu_ptr(acpi_perf_data, i);
        acpi_processor_unregister_performance(perf, i);
    }
err_out:
    /* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
    free_acpi_perf_data();
    kfree(acpi_ids_done);
    return rc;
}
static void __exit xen_acpi_processor_exit(void)
{
    int i;

    kfree(acpi_ids_done);
    for_each_possible_cpu(i) {
        struct acpi_processor_performance *perf;
        perf = per_cpu_ptr(acpi_perf_data, i);
        acpi_processor_unregister_performance(perf, i);
    }
    free_acpi_perf_data();
}

MODULE_AUTHOR("Konrad Rzeszutek Wilk <[email protected]>");
MODULE_DESCRIPTION("Xen ACPI Processor P-states (and Cx) driver which uploads PM data to Xen hypervisor");
MODULE_LICENSE("GPL");

/* We want to be loaded before the CPU freq scaling drivers are loaded.
 * They are loaded in late_initcall. */
device_initcall(xen_acpi_processor_init);
module_exit(xen_acpi_processor_exit);