// SPDX-License-Identifier: GPL-2.0-only
/*
 * intel_idle.c - native hardware idle loop for modern Intel processors
 *
 * Copyright (c) 2013 - 2020, Intel Corporation.
 * Len Brown <len.brown@intel.com>
 * Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 */

/*
 * intel_idle is a cpuidle driver that loads on all Intel CPUs with MWAIT
 * in lieu of the legacy ACPI processor_idle driver.  The intent is to
 * make Linux more efficient on these processors, as intel_idle knows
 * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
 */

/*
 * Design Assumptions
 *
 * All CPUs have same idle states as boot CPU
 *
 * Chipset BM_STS (bus master status) bit is a NOP
 *      for preventing entry into deep C-states
 *
 * CPU will flush caches as needed when entering a C-state via MWAIT
 *      (in contrast to entering ACPI C3, in which case the WBINVD
 *      instruction needs to be executed to flush the caches)
 */

/*
 * Known limitations
 *
 * ACPI has a .suspend hack to turn off deep c-statees during suspend
 * to avoid complications with the lapic timer workaround.
 * Have not seen issues with suspend, but may need same workaround here.
 *
 */

/* un-comment DEBUG to enable pr_debug() statements */
/* #define DEBUG */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/tick.h>
#include <trace/events/power.h>
#include <linux/sched.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
#include <asm/mwait.h>
#include <asm/msr.h>

#define INTEL_IDLE_VERSION "0.5.1"

static struct cpuidle_driver intel_idle_driver = {
        .name = "intel_idle",
        .owner = THIS_MODULE,
};
/* intel_idle.max_cstate=0 disables driver */
static int max_cstate = CPUIDLE_STATE_MAX - 1;
static unsigned int disabled_states_mask;

static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;

static unsigned long auto_demotion_disable_flags;
static bool disable_promotion_to_c1e;

struct idle_cpu {
        struct cpuidle_state *state_table;

        /*
         * Hardware C-state auto-demotion may not always be optimal.
         * Indicate which enable bits to clear here.
         */
        unsigned long auto_demotion_disable_flags;
        bool byt_auto_demotion_disable_flag;
        bool disable_promotion_to_c1e;
        bool use_acpi;
};

static const struct idle_cpu *icpu __initdata;
static struct cpuidle_state *cpuidle_state_table __initdata;

static unsigned int mwait_substates __initdata;

/*
 * Enable this state by default even if the ACPI _CST does not list it.
 */
#define CPUIDLE_FLAG_ALWAYS_ENABLE      BIT(15)

/*
 * MWAIT takes an 8-bit "hint" in EAX "suggesting"
 * the C-state (top nibble) and sub-state (bottom nibble)
 * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc.
 *
 * We store the hint at the top of our "flags" for each state.
 */
#define flg2MWAIT(flags) (((flags) >> 24) & 0xFF)
#define MWAIT2flg(eax) ((eax & 0xFF) << 24)

/**
 * intel_idle - Ask the processor to enter the given idle state.
 * @dev: cpuidle device of the target CPU.
 * @drv: cpuidle driver (assumed to point to intel_idle_driver).
 * @index: Target idle state index.
 *
 * Use the MWAIT instruction to notify the processor that the CPU represented by
 * @dev is idle and it can try to enter the idle state corresponding to @index.
 *
 * If the local APIC timer is not known to be reliable in the target idle state,
 * enable one-shot tick broadcasting for the target CPU before executing MWAIT.
 *
 * Optionally call leave_mm() for the target CPU upfront to avoid wakeups due to
 * flushing user TLBs.
 *
 * Must be called under local_irq_disable().
 */
static __cpuidle int intel_idle(struct cpuidle_device *dev,
                                struct cpuidle_driver *drv, int index)
{
        struct cpuidle_state *state = &drv->states[index];
        unsigned long eax = flg2MWAIT(state->flags);
        unsigned long ecx = 1; /* break on interrupt flag */

        mwait_idle_with_hints(eax, ecx);

        return index;
}

/**
 * intel_idle_s2idle - Ask the processor to enter the given idle state.
 * @dev: cpuidle device of the target CPU.
 * @drv: cpuidle driver (assumed to point to intel_idle_driver).
 * @index: Target idle state index.
 *
 * Use the MWAIT instruction to notify the processor that the CPU represented by
 * @dev is idle and it can try to enter the idle state corresponding to @index.
 *
 * Invoked as a suspend-to-idle callback routine with frozen user space, frozen
 * scheduler tick and suspended scheduler clock on the target CPU.
 */
static __cpuidle int intel_idle_s2idle(struct cpuidle_device *dev,
                                       struct cpuidle_driver *drv, int index)
{
        unsigned long eax = flg2MWAIT(drv->states[index].flags);
        unsigned long ecx = 1; /* break on interrupt flag */

        mwait_idle_with_hints(eax, ecx);

        return 0;
}

/*
 * States are indexed by the cstate number,
 * which is also the index into the MWAIT hint array.
 * Thus C0 is a dummy.
 */
static struct cpuidle_state nehalem_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 3,
                .target_residency = 6,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 20,
                .target_residency = 80,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 200,
                .target_residency = 800,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state snb_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 80,
                .target_residency = 211,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 104,
                .target_residency = 345,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7",
                .desc = "MWAIT 0x30",
                .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 109,
                .target_residency = 345,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state byt_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6N",
                .desc = "MWAIT 0x58",
                .flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 300,
                .target_residency = 275,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6S",
                .desc = "MWAIT 0x52",
                .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 500,
                .target_residency = 560,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 1200,
                .target_residency = 4000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7S",
                .desc = "MWAIT 0x64",
                .flags = MWAIT2flg(0x64) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 10000,
                .target_residency = 20000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state cht_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6N",
                .desc = "MWAIT 0x58",
                .flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 80,
                .target_residency = 275,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6S",
                .desc = "MWAIT 0x52",
                .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 200,
                .target_residency = 560,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 1200,
                .target_residency = 4000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7S",
                .desc = "MWAIT 0x64",
                .flags = MWAIT2flg(0x64) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 10000,
                .target_residency = 20000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state ivb_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 59,
                .target_residency = 156,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 80,
                .target_residency = 300,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7",
                .desc = "MWAIT 0x30",
                .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 87,
                .target_residency = 300,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state ivt_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 80,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 59,
                .target_residency = 156,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 82,
                .target_residency = 300,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state ivt_cstates_4s[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 250,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 59,
                .target_residency = 300,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 84,
                .target_residency = 400,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state ivt_cstates_8s[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 500,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 59,
                .target_residency = 600,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 88,
                .target_residency = 700,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state hsw_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 33,
                .target_residency = 100,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 133,
                .target_residency = 400,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7s",
                .desc = "MWAIT 0x32",
                .flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 166,
                .target_residency = 500,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C8",
                .desc = "MWAIT 0x40",
                .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 300,
                .target_residency = 900,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C9",
                .desc = "MWAIT 0x50",
                .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 600,
                .target_residency = 1800,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C10",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 2600,
                .target_residency = 7700,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};
static struct cpuidle_state bdw_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 40,
                .target_residency = 100,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 133,
                .target_residency = 400,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7s",
                .desc = "MWAIT 0x32",
                .flags = MWAIT2flg(0x32) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 166,
                .target_residency = 500,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C8",
                .desc = "MWAIT 0x40",
                .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 300,
                .target_residency = 900,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C9",
                .desc = "MWAIT 0x50",
                .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 600,
                .target_residency = 1800,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C10",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 2600,
                .target_residency = 7700,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state skl_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C3",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 70,
                .target_residency = 100,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 85,
                .target_residency = 200,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7s",
                .desc = "MWAIT 0x33",
                .flags = MWAIT2flg(0x33) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 124,
                .target_residency = 800,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C8",
                .desc = "MWAIT 0x40",
                .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 200,
                .target_residency = 800,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C9",
                .desc = "MWAIT 0x50",
                .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 480,
                .target_residency = 5000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C10",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 890,
                .target_residency = 5000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state skx_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 133,
                .target_residency = 600,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state icx_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 1,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 4,
                .target_residency = 4,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 128,
                .target_residency = 384,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state atom_cstates[] __initdata = {
        {
                .name = "C1E",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C2",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10),
                .exit_latency = 20,
                .target_residency = 80,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C4",
                .desc = "MWAIT 0x30",
                .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 100,
                .target_residency = 400,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x52",
                .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 140,
                .target_residency = 560,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};
static struct cpuidle_state tangier_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 4,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C4",
                .desc = "MWAIT 0x30",
                .flags = MWAIT2flg(0x30) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 100,
                .target_residency = 400,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x52",
                .flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 140,
                .target_residency = 560,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 1200,
                .target_residency = 4000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C9",
                .desc = "MWAIT 0x64",
                .flags = MWAIT2flg(0x64) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 10000,
                .target_residency = 20000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};
static struct cpuidle_state avn_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x51",
                .flags = MWAIT2flg(0x51) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 15,
                .target_residency = 45,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};
static struct cpuidle_state knl_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 1,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle },
        {
                .name = "C6",
                .desc = "MWAIT 0x10",
                .flags = MWAIT2flg(0x10) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 120,
                .target_residency = 500,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle },
        {
                .enter = NULL }
};

static struct cpuidle_state bxt_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 133,
                .target_residency = 133,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C7s",
                .desc = "MWAIT 0x31",
                .flags = MWAIT2flg(0x31) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 155,
                .target_residency = 155,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C8",
                .desc = "MWAIT 0x40",
                .flags = MWAIT2flg(0x40) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 1000,
                .target_residency = 1000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C9",
                .desc = "MWAIT 0x50",
                .flags = MWAIT2flg(0x50) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 2000,
                .target_residency = 2000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C10",
                .desc = "MWAIT 0x60",
                .flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 10000,
                .target_residency = 10000,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static struct cpuidle_state dnv_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 10,
                .target_residency = 20,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 50,
                .target_residency = 500,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

/*
 * Note, depending on HW and FW revision, SnowRidge SoC may or may not support
 * C6, and this is indicated in the CPUID mwait leaf.
 */
static struct cpuidle_state snr_cstates[] __initdata = {
        {
                .name = "C1",
                .desc = "MWAIT 0x00",
                .flags = MWAIT2flg(0x00),
                .exit_latency = 2,
                .target_residency = 2,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C1E",
                .desc = "MWAIT 0x01",
                .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
                .exit_latency = 15,
                .target_residency = 25,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .name = "C6",
                .desc = "MWAIT 0x20",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
                .exit_latency = 130,
                .target_residency = 500,
                .enter = &intel_idle,
                .enter_s2idle = intel_idle_s2idle, },
        {
                .enter = NULL }
};

static const struct idle_cpu idle_cpu_nehalem __initconst = {
        .state_table = nehalem_cstates,

        .auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_nhx __initconst = {
        .state_table = nehalem_cstates,
        .auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_atom __initconst = {
        .state_table = atom_cstates,
};

static const struct idle_cpu idle_cpu_tangier __initconst = {
        .state_table = tangier_cstates,
};

static const struct idle_cpu idle_cpu_lincroft __initconst = {
        .state_table = atom_cstates,
        .auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE,
};

static const struct idle_cpu idle_cpu_snb __initconst = {
        .state_table = snb_cstates,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_snx __initconst = {
        .state_table = snb_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_byt __initconst = {
        .state_table = byt_cstates,
        .disable_promotion_to_c1e = true,
        .byt_auto_demotion_disable_flag = true,
};

static const struct idle_cpu idle_cpu_cht __initconst = {
        .state_table = cht_cstates,
        .disable_promotion_to_c1e = true,
        .byt_auto_demotion_disable_flag = true,
};

static const struct idle_cpu idle_cpu_ivb __initconst = {
        .state_table = ivb_cstates,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_ivt __initconst = {
        .state_table = ivt_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_hsw __initconst = {
        .state_table = hsw_cstates,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_hsx __initconst = {
        .state_table = hsw_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_bdw __initconst = {
        .state_table = bdw_cstates,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_bdx __initconst = {
        .state_table = bdw_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_skl __initconst = {
        .state_table = skl_cstates,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_skx __initconst = {
        .state_table = skx_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_icx __initconst = {
        .state_table = icx_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_avn __initconst = {
        .state_table = avn_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_knl __initconst = {
        .state_table = knl_cstates,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_bxt __initconst = {
        .state_table = bxt_cstates,
        .disable_promotion_to_c1e = true,
};

static const struct idle_cpu idle_cpu_dnv __initconst = {
        .state_table = dnv_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct idle_cpu idle_cpu_snr __initconst = {
        .state_table = snr_cstates,
        .disable_promotion_to_c1e = true,
        .use_acpi = true,
};

static const struct x86_cpu_id intel_idle_ids[] __initconst = {
        X86_MATCH_INTEL_FAM6_MODEL(NEHALEM_EP,          &idle_cpu_nhx),
        X86_MATCH_INTEL_FAM6_MODEL(NEHALEM,             &idle_cpu_nehalem),
        X86_MATCH_INTEL_FAM6_MODEL(NEHALEM_G,           &idle_cpu_nehalem),
        X86_MATCH_INTEL_FAM6_MODEL(WESTMERE,            &idle_cpu_nehalem),
        X86_MATCH_INTEL_FAM6_MODEL(WESTMERE_EP,         &idle_cpu_nhx),
        X86_MATCH_INTEL_FAM6_MODEL(NEHALEM_EX,          &idle_cpu_nhx),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_BONNELL,        &idle_cpu_atom),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_BONNELL_MID,    &idle_cpu_lincroft),
        X86_MATCH_INTEL_FAM6_MODEL(WESTMERE_EX,         &idle_cpu_nhx),
        X86_MATCH_INTEL_FAM6_MODEL(SANDYBRIDGE,         &idle_cpu_snb),
        X86_MATCH_INTEL_FAM6_MODEL(SANDYBRIDGE_X,       &idle_cpu_snx),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_SALTWELL,       &idle_cpu_atom),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT,     &idle_cpu_byt),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT_MID, &idle_cpu_tangier),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_AIRMONT,        &idle_cpu_cht),
        X86_MATCH_INTEL_FAM6_MODEL(IVYBRIDGE,           &idle_cpu_ivb),
        X86_MATCH_INTEL_FAM6_MODEL(IVYBRIDGE_X,         &idle_cpu_ivt),
        X86_MATCH_INTEL_FAM6_MODEL(HASWELL,             &idle_cpu_hsw),
        X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X,           &idle_cpu_hsx),
        X86_MATCH_INTEL_FAM6_MODEL(HASWELL_L,           &idle_cpu_hsw),
        X86_MATCH_INTEL_FAM6_MODEL(HASWELL_G,           &idle_cpu_hsw),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT_D,   &idle_cpu_avn),
        X86_MATCH_INTEL_FAM6_MODEL(BROADWELL,           &idle_cpu_bdw),
        X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_G,         &idle_cpu_bdw),
        X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X,         &idle_cpu_bdx),
        X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_D,         &idle_cpu_bdx),
        X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_L,           &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE,             &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L,          &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE,            &idle_cpu_skl),
        X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X,           &idle_cpu_skx),
        X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,           &idle_cpu_icx),
        X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,           &idle_cpu_icx),
        X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL,        &idle_cpu_knl),
        X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM,        &idle_cpu_knl),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_GOLDMONT,       &idle_cpu_bxt),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_GOLDMONT_PLUS,  &idle_cpu_bxt),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_GOLDMONT_D,     &idle_cpu_dnv),
        X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_D,      &idle_cpu_snr),
        {}
};

static const struct x86_cpu_id intel_mwait_ids[] __initconst = {
        X86_MATCH_VENDOR_FAM_FEATURE(INTEL, 6, X86_FEATURE_MWAIT, NULL),
        {}
};

static bool __init intel_idle_max_cstate_reached(int cstate)
{
        if (cstate + 1 > max_cstate) {
                pr_info("max_cstate %d reached\n", max_cstate);
                return true;
        }
        return false;
}

static bool __init intel_idle_state_needs_timer_stop(struct cpuidle_state *state)
{
        unsigned long eax = flg2MWAIT(state->flags);

        if (boot_cpu_has(X86_FEATURE_ARAT))
                return false;

        /*
         * Switch over to one-shot tick broadcast if the target C-state
         * is deeper than C1.
         */
        return !!((eax >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK);
}

#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
#include <acpi/processor.h>

static bool no_acpi __read_mostly;
module_param(no_acpi, bool, 0444);
MODULE_PARM_DESC(no_acpi, "Do not use ACPI _CST for building the idle states list");

static bool force_use_acpi __read_mostly; /* No effect if no_acpi is set. */
module_param_named(use_acpi, force_use_acpi, bool, 0444);
MODULE_PARM_DESC(use_acpi, "Use ACPI _CST for building the idle states list");

static struct acpi_processor_power acpi_state_table __initdata;

/**
 * intel_idle_cst_usable - Check if the _CST information can be used.
 *
 * Check if all of the C-states listed by _CST in the max_cstate range are
 * ACPI_CSTATE_FFH, which means that they should be entered via MWAIT.
 */
static bool __init intel_idle_cst_usable(void)
{
        int cstate, limit;

        limit = min_t(int, min_t(int, CPUIDLE_STATE_MAX, max_cstate + 1),
                      acpi_state_table.count);

        for (cstate = 1; cstate < limit; cstate++) {
                struct acpi_processor_cx *cx = &acpi_state_table.states[cstate];

                if (cx->entry_method != ACPI_CSTATE_FFH)
                        return false;
        }

        return true;
}

static bool __init intel_idle_acpi_cst_extract(void)
{
        unsigned int cpu;

        if (no_acpi) {
                pr_debug("Not allowed to use ACPI _CST\n");
                return false;
        }

        for_each_possible_cpu(cpu) {
                struct acpi_processor *pr = per_cpu(processors, cpu);

                if (!pr)
                        continue;

                if (acpi_processor_evaluate_cst(pr->handle, cpu, &acpi_state_table))
                        continue;

                acpi_state_table.count++;

                if (!intel_idle_cst_usable())
                        continue;

                if (!acpi_processor_claim_cst_control())
                        break;

                return true;
        }

        acpi_state_table.count = 0;
        pr_debug("ACPI _CST not found or not usable\n");
        return false;
}

static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
{
        int cstate, limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count);

        /*
         * If limit > 0, intel_idle_cst_usable() has returned 'true', so all of
         * the interesting states are ACPI_CSTATE_FFH.
         */
        for (cstate = 1; cstate < limit; cstate++) {
                struct acpi_processor_cx *cx;
                struct cpuidle_state *state;

                if (intel_idle_max_cstate_reached(cstate - 1))
                        break;

                cx = &acpi_state_table.states[cstate];

                state = &drv->states[drv->state_count++];

                snprintf(state->name, CPUIDLE_NAME_LEN, "C%d_ACPI", cstate);
                strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
                state->exit_latency = cx->latency;
                /*
                 * For C1-type C-states use the same number for both the exit
                 * latency and target residency, because that is the case for
                 * C1 in the majority of the static C-states tables above.
                 * For the other types of C-states, however, set the target
                 * residency to 3 times the exit latency which should lead to
                 * a reasonable balance between energy-efficiency and
                 * performance in the majority of interesting cases.
                 */
                state->target_residency = cx->latency;
                if (cx->type > ACPI_STATE_C1)
                        state->target_residency *= 3;

                state->flags = MWAIT2flg(cx->address);
                if (cx->type > ACPI_STATE_C2)
                        state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;

                if (disabled_states_mask & BIT(cstate))
                        state->flags |= CPUIDLE_FLAG_OFF;

                if (intel_idle_state_needs_timer_stop(state))
                        state->flags |= CPUIDLE_FLAG_TIMER_STOP;

                state->enter = intel_idle;
                state->enter_s2idle = intel_idle_s2idle;
        }
}

static bool __init intel_idle_off_by_default(u32 mwait_hint)
{
        int cstate, limit;

        /*
         * If there are no _CST C-states, do not disable any C-states by
         * default.
         */
        if (!acpi_state_table.count)
                return false;

        limit = min_t(int, CPUIDLE_STATE_MAX, acpi_state_table.count);
        /*
         * If limit > 0, intel_idle_cst_usable() has returned 'true', so all of
         * the interesting states are ACPI_CSTATE_FFH.
         */
        for (cstate = 1; cstate < limit; cstate++) {
                if (acpi_state_table.states[cstate].address == mwait_hint)
                        return false;
        }
        return true;
}
#else /* !CONFIG_ACPI_PROCESSOR_CSTATE */
#define force_use_acpi  (false)

static inline bool intel_idle_acpi_cst_extract(void) { return false; }
static inline void intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) { }
static inline bool intel_idle_off_by_default(u32 mwait_hint) { return false; }
#endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */

/**
 * ivt_idle_state_table_update - Tune the idle states table for Ivy Town.
 *
 * Tune IVT multi-socket targets.
 * Assumption: num_sockets == (max_package_num + 1).
 */
static void __init ivt_idle_state_table_update(void)
{
        /* IVT uses a different table for 1-2, 3-4, and > 4 sockets */
        int cpu, package_num, num_sockets = 1;

        for_each_online_cpu(cpu) {
                package_num = topology_physical_package_id(cpu);
                if (package_num + 1 > num_sockets) {
                        num_sockets = package_num + 1;

                        if (num_sockets > 4) {
                                cpuidle_state_table = ivt_cstates_8s;
                                return;
                        }
                }
        }

        if (num_sockets > 2)
                cpuidle_state_table = ivt_cstates_4s;

        /* else, 1 and 2 socket systems use default ivt_cstates */
}

/**
 * irtl_2_usec - IRTL to microseconds conversion.
 * @irtl: IRTL MSR value.
 *
 * Translate the IRTL (Interrupt Response Time Limit) MSR value to microseconds.
 */
static unsigned long long __init irtl_2_usec(unsigned long long irtl)
{
        static const unsigned int irtl_ns_units[] __initconst = {
                1, 32, 1024, 32768, 1048576, 33554432, 0, 0
        };
        unsigned long long ns;

        if (!irtl)
                return 0;

        ns = irtl_ns_units[(irtl >> 10) & 0x7];

        return div_u64((irtl & 0x3FF) * ns, NSEC_PER_USEC);
}

/**
 * bxt_idle_state_table_update - Fix up the Broxton idle states table.
 *
 * On BXT, trust the IRTL (Interrupt Response Time Limit) MSR to show the
 * definitive maximum latency and use the same value for target_residency.
 */
static void __init bxt_idle_state_table_update(void)
{
        unsigned long long msr;
        unsigned int usec;

        rdmsrl(MSR_PKGC6_IRTL, msr);
        usec = irtl_2_usec(msr);
        if (usec) {
                bxt_cstates[2].exit_latency = usec;
                bxt_cstates[2].target_residency = usec;
        }

        rdmsrl(MSR_PKGC7_IRTL, msr);
        usec = irtl_2_usec(msr);
        if (usec) {
                bxt_cstates[3].exit_latency = usec;
                bxt_cstates[3].target_residency = usec;
        }

        rdmsrl(MSR_PKGC8_IRTL, msr);
        usec = irtl_2_usec(msr);
        if (usec) {
                bxt_cstates[4].exit_latency = usec;
                bxt_cstates[4].target_residency = usec;
        }

        rdmsrl(MSR_PKGC9_IRTL, msr);
        usec = irtl_2_usec(msr);
        if (usec) {
                bxt_cstates[5].exit_latency = usec;
                bxt_cstates[5].target_residency = usec;
        }

        rdmsrl(MSR_PKGC10_IRTL, msr);
        usec = irtl_2_usec(msr);
        if (usec) {
                bxt_cstates[6].exit_latency = usec;
                bxt_cstates[6].target_residency = usec;
        }

}

/**
 * sklh_idle_state_table_update - Fix up the Sky Lake idle states table.
 *
 * On SKL-H (model 0x5e) skip C8 and C9 if C10 is enabled and SGX disabled.
 */
static void __init sklh_idle_state_table_update(void)
{
        unsigned long long msr;
        unsigned int eax, ebx, ecx, edx;


        /* if PC10 disabled via cmdline intel_idle.max_cstate=7 or shallower */
        if (max_cstate <= 7)
                return;

        /* if PC10 not present in CPUID.MWAIT.EDX */
        if ((mwait_substates & (0xF << 28)) == 0)
                return;

        rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr);

        /* PC10 is not enabled in PKG C-state limit */
        if ((msr & 0xF) != 8)
                return;

        ecx = 0;
        cpuid(7, &eax, &ebx, &ecx, &edx);

        /* if SGX is present */
        if (ebx & (1 << 2)) {

                rdmsrl(MSR_IA32_FEAT_CTL, msr);

                /* if SGX is enabled */
                if (msr & (1 << 18))
                        return;
        }

        skl_cstates[5].flags |= CPUIDLE_FLAG_UNUSABLE;  /* C8-SKL */
        skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;  /* C9-SKL */
}

static bool __init intel_idle_verify_cstate(unsigned int mwait_hint)
{
        unsigned int mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint) + 1;
        unsigned int num_substates = (mwait_substates >> mwait_cstate * 4) &
                                        MWAIT_SUBSTATE_MASK;

        /* Ignore the C-state if there are NO sub-states in CPUID for it. */
        if (num_substates == 0)
                return false;

        if (mwait_cstate > 2 && !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
                mark_tsc_unstable("TSC halts in idle states deeper than C2");

        return true;
}

static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
{
        int cstate;

        switch (boot_cpu_data.x86_model) {
        case INTEL_FAM6_IVYBRIDGE_X:
                ivt_idle_state_table_update();
                break;
        case INTEL_FAM6_ATOM_GOLDMONT:
        case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
                bxt_idle_state_table_update();
                break;
        case INTEL_FAM6_SKYLAKE:
                sklh_idle_state_table_update();
                break;
        }

        for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) {
                unsigned int mwait_hint;

                if (intel_idle_max_cstate_reached(cstate))
                        break;

                if (!cpuidle_state_table[cstate].enter &&
                    !cpuidle_state_table[cstate].enter_s2idle)
                        break;

                /* If marked as unusable, skip this state. */
                if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_UNUSABLE) {
                        pr_debug("state %s is disabled\n",
                                 cpuidle_state_table[cstate].name);
                        continue;
                }

                mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
                if (!intel_idle_verify_cstate(mwait_hint))
                        continue;

                /* Structure copy. */
                drv->states[drv->state_count] = cpuidle_state_table[cstate];

                if ((disabled_states_mask & BIT(drv->state_count)) ||
                    ((icpu->use_acpi && force_use_acpi) &&
                     intel_idle_off_by_default(mwait_hint) &&
                     !(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE)))
                        drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF;

                if (intel_idle_state_needs_timer_stop(&drv->states[drv->state_count]))
                        drv->states[drv->state_count].flags |= CPUIDLE_FLAG_TIMER_STOP;

                drv->state_count++;
        }

        if (icpu->byt_auto_demotion_disable_flag) {
                wrmsrl(MSR_CC6_DEMOTION_POLICY_CONFIG, 0);
                wrmsrl(MSR_MC6_DEMOTION_POLICY_CONFIG, 0);
        }
}

/**
 * intel_idle_cpuidle_driver_init - Create the list of available idle states.
 * @drv: cpuidle driver structure to initialize.
 */
static void __init intel_idle_cpuidle_driver_init(struct cpuidle_driver *drv)
{
        cpuidle_poll_state_init(drv);

        if (disabled_states_mask & BIT(0))
                drv->states[0].flags |= CPUIDLE_FLAG_OFF;

        drv->state_count = 1;

        if (icpu)
                intel_idle_init_cstates_icpu(drv);
        else
                intel_idle_init_cstates_acpi(drv);
}

static void auto_demotion_disable(void)
{
        unsigned long long msr_bits;

        rdmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_bits);
        msr_bits &= ~auto_demotion_disable_flags;
        wrmsrl(MSR_PKG_CST_CONFIG_CONTROL, msr_bits);
}

static void c1e_promotion_disable(void)
{
        unsigned long long msr_bits;

        rdmsrl(MSR_IA32_POWER_CTL, msr_bits);
        msr_bits &= ~0x2;
        wrmsrl(MSR_IA32_POWER_CTL, msr_bits);
}

/**
 * intel_idle_cpu_init - Register the target CPU with the cpuidle core.
 * @cpu: CPU to initialize.
 *
 * Register a cpuidle device object for @cpu and update its MSRs in accordance
 * with the processor model flags.
 */
static int intel_idle_cpu_init(unsigned int cpu)
{
        struct cpuidle_device *dev;

        dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);
        dev->cpu = cpu;

        if (cpuidle_register_device(dev)) {
                pr_debug("cpuidle_register_device %d failed!\n", cpu);
                return -EIO;
        }

        if (auto_demotion_disable_flags)
                auto_demotion_disable();

        if (disable_promotion_to_c1e)
                c1e_promotion_disable();

        return 0;
}

static int intel_idle_cpu_online(unsigned int cpu)
{
        struct cpuidle_device *dev;

        if (!boot_cpu_has(X86_FEATURE_ARAT))
                tick_broadcast_enable();

        /*
         * Some systems can hotplug a cpu at runtime after
         * the kernel has booted, we have to initialize the
         * driver in this case
         */
        dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);
        if (!dev->registered)
                return intel_idle_cpu_init(cpu);

        return 0;
}

/**
 * intel_idle_cpuidle_devices_uninit - Unregister all cpuidle devices.
 */
static void __init intel_idle_cpuidle_devices_uninit(void)
{
        int i;

        for_each_online_cpu(i)
                cpuidle_unregister_device(per_cpu_ptr(intel_idle_cpuidle_devices, i));
}

static int __init intel_idle_init(void)
{
        const struct x86_cpu_id *id;
        unsigned int eax, ebx, ecx;
        int retval;

        /* Do not load intel_idle at all for now if idle= is passed */
        if (boot_option_idle_override != IDLE_NO_OVERRIDE)
                return -ENODEV;

        if (max_cstate == 0) {
                pr_debug("disabled\n");
                return -EPERM;
        }

        id = x86_match_cpu(intel_idle_ids);
        if (id) {
                if (!boot_cpu_has(X86_FEATURE_MWAIT)) {
                        pr_debug("Please enable MWAIT in BIOS SETUP\n");
                        return -ENODEV;
                }
        } else {
                id = x86_match_cpu(intel_mwait_ids);
                if (!id)
                        return -ENODEV;
        }

        if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
                return -ENODEV;

        cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);

        if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
            !(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
            !mwait_substates)
                        return -ENODEV;

        pr_debug("MWAIT substates: 0x%x\n", mwait_substates);

        icpu = (const struct idle_cpu *)id->driver_data;
        if (icpu) {
                cpuidle_state_table = icpu->state_table;
                auto_demotion_disable_flags = icpu->auto_demotion_disable_flags;
                disable_promotion_to_c1e = icpu->disable_promotion_to_c1e;
                if (icpu->use_acpi && force_use_acpi)
                        intel_idle_acpi_cst_extract();
        } else if (!intel_idle_acpi_cst_extract()) {
                return -ENODEV;
        }

        pr_debug("v" INTEL_IDLE_VERSION " model 0x%X\n",
                 boot_cpu_data.x86_model);

        intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
        if (!intel_idle_cpuidle_devices)
                return -ENOMEM;

        intel_idle_cpuidle_driver_init(&intel_idle_driver);

        retval = cpuidle_register_driver(&intel_idle_driver);
        if (retval) {
                struct cpuidle_driver *drv = cpuidle_get_driver();
                printk(KERN_DEBUG pr_fmt("intel_idle yielding to %s\n"),
                       drv ? drv->name : "none");
                goto init_driver_fail;
        }

        retval = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "idle/intel:online",
                                   intel_idle_cpu_online, NULL);
        if (retval < 0)
                goto hp_setup_fail;

        pr_debug("Local APIC timer is reliable in %s\n",
                 boot_cpu_has(X86_FEATURE_ARAT) ? "all C-states" : "C1");

        return 0;

hp_setup_fail:
        intel_idle_cpuidle_devices_uninit();
        cpuidle_unregister_driver(&intel_idle_driver);
init_driver_fail:
        free_percpu(intel_idle_cpuidle_devices);
        return retval;

}
device_initcall(intel_idle_init);

/*
 * We are not really modular, but we used to support that.  Meaning we also
 * support "intel_idle.max_cstate=..." at boot and also a read-only export of
 * it at /sys/module/intel_idle/parameters/max_cstate -- so using module_param
 * is the easiest way (currently) to continue doing that.
 */
module_param(max_cstate, int, 0444);
/*
 * The positions of the bits that are set in this number are the indices of the
 * idle states to be disabled by default (as reflected by the names of the
 * corresponding idle state directories in sysfs, "state0", "state1" ...
 * "state<i>" ..., where <i> is the index of the given state).
 */
module_param_named(states_off, disabled_states_mask, uint, 0444);
MODULE_PARM_DESC(states_off, "Mask of disabled idle states");