/**
 * @file nmi_int.c
 *
 * @remark Copyright 2002-2009 OProfile authors
 * @remark Read the file COPYING
 *
 * @author John Levon <levon@movementarian.org>
 * @author Robert Richter <robert.richter@amd.com>
 * @author Barry Kasindorf <barry.kasindorf@amd.com>
 * @author Jason Yeh <jason.yeh@amd.com>
 * @author Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
 */

#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#include <linux/oprofile.h>
#include <linux/syscore_ops.h>
#include <linux/slab.h>
#include <linux/moduleparam.h>
#include <linux/kdebug.h>
#include <linux/cpu.h>
#include <asm/nmi.h>
#include <asm/msr.h>
#include <asm/apic.h>

#include "op_counter.h"
#include "op_x86_model.h"

static struct op_x86_model_spec *model;
static DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
static DEFINE_PER_CPU(unsigned long, saved_lvtpc);

/* must be protected with get_online_cpus()/put_online_cpus(): */
static int nmi_enabled;
static int ctr_running;

struct op_counter_config counter_config[OP_MAX_COUNTER];

/* common functions */

u64 op_x86_get_ctrl(struct op_x86_model_spec const *model,
                    struct op_counter_config *counter_config)
{
        u64 val = 0;
        u16 event = (u16)counter_config->event;

        val |= ARCH_PERFMON_EVENTSEL_INT;
        val |= counter_config->user ? ARCH_PERFMON_EVENTSEL_USR : 0;
        val |= counter_config->kernel ? ARCH_PERFMON_EVENTSEL_OS : 0;
        val |= (counter_config->unit_mask & 0xFF) << 8;
        counter_config->extra &= (ARCH_PERFMON_EVENTSEL_INV |
                                  ARCH_PERFMON_EVENTSEL_EDGE |
                                  ARCH_PERFMON_EVENTSEL_CMASK);
        val |= counter_config->extra;
        event &= model->event_mask ? model->event_mask : 0xFF;
        val |= event & 0xFF;
        val |= (u64)(event & 0x0F00) << 24;

        return val;
}


static int profile_exceptions_notify(unsigned int val, struct pt_regs *regs)
{
        if (ctr_running)
                model->check_ctrs(regs, this_cpu_ptr(&cpu_msrs));
        else if (!nmi_enabled)
                return NMI_DONE;
        else
                model->stop(this_cpu_ptr(&cpu_msrs));
        return NMI_HANDLED;
}

static void nmi_cpu_save_registers(struct op_msrs *msrs)
{
        struct op_msr *counters = msrs->counters;
        struct op_msr *controls = msrs->controls;
        unsigned int i;

        for (i = 0; i < model->num_counters; ++i) {
                if (counters[i].addr)
                        rdmsrl(counters[i].addr, counters[i].saved);
        }

        for (i = 0; i < model->num_controls; ++i) {
                if (controls[i].addr)
                        rdmsrl(controls[i].addr, controls[i].saved);
        }
}

static void nmi_cpu_start(void *dummy)
{
        struct op_msrs const *msrs = this_cpu_ptr(&cpu_msrs);
        if (!msrs->controls)
                WARN_ON_ONCE(1);
        else
                model->start(msrs);
}

static int nmi_start(void)
{
        get_online_cpus();
        ctr_running = 1;
        /* make ctr_running visible to the nmi handler: */
        smp_mb();
        on_each_cpu(nmi_cpu_start, NULL, 1);
        put_online_cpus();
        return 0;
}

static void nmi_cpu_stop(void *dummy)
{
        struct op_msrs const *msrs = this_cpu_ptr(&cpu_msrs);
        if (!msrs->controls)
                WARN_ON_ONCE(1);
        else
                model->stop(msrs);
}

static void nmi_stop(void)
{
        get_online_cpus();
        on_each_cpu(nmi_cpu_stop, NULL, 1);
        ctr_running = 0;
        put_online_cpus();
}

#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX

static DEFINE_PER_CPU(int, switch_index);

static inline int has_mux(void)
{
        return !!model->switch_ctrl;
}

inline int op_x86_phys_to_virt(int phys)
{
        return __this_cpu_read(switch_index) + phys;
}

inline int op_x86_virt_to_phys(int virt)
{
        return virt % model->num_counters;
}

static void nmi_shutdown_mux(void)
{
        int i;

        if (!has_mux())
                return;

        for_each_possible_cpu(i) {
                kfree(per_cpu(cpu_msrs, i).multiplex);
                per_cpu(cpu_msrs, i).multiplex = NULL;
                per_cpu(switch_index, i) = 0;
        }
}

static int nmi_setup_mux(void)
{
        size_t multiplex_size =
                sizeof(struct op_msr) * model->num_virt_counters;
        int i;

        if (!has_mux())
                return 1;

        for_each_possible_cpu(i) {
                per_cpu(cpu_msrs, i).multiplex =
                        kzalloc(multiplex_size, GFP_KERNEL);
                if (!per_cpu(cpu_msrs, i).multiplex)
                        return 0;
        }

        return 1;
}

static void nmi_cpu_setup_mux(int cpu, struct op_msrs const * const msrs)
{
        int i;
        struct op_msr *multiplex = msrs->multiplex;

        if (!has_mux())
                return;

        for (i = 0; i < model->num_virt_counters; ++i) {
                if (counter_config[i].enabled) {
                        multiplex[i].saved = -(u64)counter_config[i].count;
                } else {
                        multiplex[i].saved = 0;
                }
        }

        per_cpu(switch_index, cpu) = 0;
}

static void nmi_cpu_save_mpx_registers(struct op_msrs *msrs)
{
        struct op_msr *counters = msrs->counters;
        struct op_msr *multiplex = msrs->multiplex;
        int i;

        for (i = 0; i < model->num_counters; ++i) {
                int virt = op_x86_phys_to_virt(i);
                if (counters[i].addr)
                        rdmsrl(counters[i].addr, multiplex[virt].saved);
        }
}

static void nmi_cpu_restore_mpx_registers(struct op_msrs *msrs)
{
        struct op_msr *counters = msrs->counters;
        struct op_msr *multiplex = msrs->multiplex;
        int i;

        for (i = 0; i < model->num_counters; ++i) {
                int virt = op_x86_phys_to_virt(i);
                if (counters[i].addr)
                        wrmsrl(counters[i].addr, multiplex[virt].saved);
        }
}

static void nmi_cpu_switch(void *dummy)
{
        int cpu = smp_processor_id();
        int si = per_cpu(switch_index, cpu);
        struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);

        nmi_cpu_stop(NULL);
        nmi_cpu_save_mpx_registers(msrs);

        /* move to next set */
        si += model->num_counters;
        if ((si >= model->num_virt_counters) || (counter_config[si].count == 0))
                per_cpu(switch_index, cpu) = 0;
        else
                per_cpu(switch_index, cpu) = si;

        model->switch_ctrl(model, msrs);
        nmi_cpu_restore_mpx_registers(msrs);

        nmi_cpu_start(NULL);
}


/*
 * Quick check to see if multiplexing is necessary.
 * The check should be sufficient since counters are used
 * in ordre.
 */
static int nmi_multiplex_on(void)
{
        return counter_config[model->num_counters].count ? 0 : -EINVAL;
}

static int nmi_switch_event(void)
{
        if (!has_mux())
                return -ENOSYS;         /* not implemented */
        if (nmi_multiplex_on() < 0)
                return -EINVAL;         /* not necessary */

        get_online_cpus();
        if (ctr_running)
                on_each_cpu(nmi_cpu_switch, NULL, 1);
        put_online_cpus();

        return 0;
}

static inline void mux_init(struct oprofile_operations *ops)
{
        if (has_mux())
                ops->switch_events = nmi_switch_event;
}

static void mux_clone(int cpu)
{
        if (!has_mux())
                return;

        memcpy(per_cpu(cpu_msrs, cpu).multiplex,
               per_cpu(cpu_msrs, 0).multiplex,
               sizeof(struct op_msr) * model->num_virt_counters);
}

#else

inline int op_x86_phys_to_virt(int phys) { return phys; }
inline int op_x86_virt_to_phys(int virt) { return virt; }
static inline void nmi_shutdown_mux(void) { }
static inline int nmi_setup_mux(void) { return 1; }
static inline void
nmi_cpu_setup_mux(int cpu, struct op_msrs const * const msrs) { }
static inline void mux_init(struct oprofile_operations *ops) { }
static void mux_clone(int cpu) { }

#endif

static void free_msrs(void)
{
        int i;
        for_each_possible_cpu(i) {
                kfree(per_cpu(cpu_msrs, i).counters);
                per_cpu(cpu_msrs, i).counters = NULL;
                kfree(per_cpu(cpu_msrs, i).controls);
                per_cpu(cpu_msrs, i).controls = NULL;
        }
        nmi_shutdown_mux();
}

static int allocate_msrs(void)
{
        size_t controls_size = sizeof(struct op_msr) * model->num_controls;
        size_t counters_size = sizeof(struct op_msr) * model->num_counters;

        int i;
        for_each_possible_cpu(i) {
                per_cpu(cpu_msrs, i).counters = kzalloc(counters_size,
                                                        GFP_KERNEL);
                if (!per_cpu(cpu_msrs, i).counters)
                        goto fail;
                per_cpu(cpu_msrs, i).controls = kzalloc(controls_size,
                                                        GFP_KERNEL);
                if (!per_cpu(cpu_msrs, i).controls)
                        goto fail;
        }

        if (!nmi_setup_mux())
                goto fail;

        return 1;

fail:
        free_msrs();
        return 0;
}

static void nmi_cpu_setup(void)
{
        int cpu = smp_processor_id();
        struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);

        nmi_cpu_save_registers(msrs);
        raw_spin_lock(&oprofilefs_lock);
        model->setup_ctrs(model, msrs);
        nmi_cpu_setup_mux(cpu, msrs);
        raw_spin_unlock(&oprofilefs_lock);
        per_cpu(saved_lvtpc, cpu) = apic_read(APIC_LVTPC);
        apic_write(APIC_LVTPC, APIC_DM_NMI);
}

static void nmi_cpu_restore_registers(struct op_msrs *msrs)
{
        struct op_msr *counters = msrs->counters;
        struct op_msr *controls = msrs->controls;
        unsigned int i;

        for (i = 0; i < model->num_controls; ++i) {
                if (controls[i].addr)
                        wrmsrl(controls[i].addr, controls[i].saved);
        }

        for (i = 0; i < model->num_counters; ++i) {
                if (counters[i].addr)
                        wrmsrl(counters[i].addr, counters[i].saved);
        }
}

static void nmi_cpu_shutdown(void)
{
        unsigned int v;
        int cpu = smp_processor_id();
        struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);

        /* restoring APIC_LVTPC can trigger an apic error because the delivery
         * mode and vector nr combination can be illegal. That's by design: on
         * power on apic lvt contain a zero vector nr which are legal only for
         * NMI delivery mode. So inhibit apic err before restoring lvtpc
         */
        v = apic_read(APIC_LVTERR);
        apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
        apic_write(APIC_LVTPC, per_cpu(saved_lvtpc, cpu));
        apic_write(APIC_LVTERR, v);
        nmi_cpu_restore_registers(msrs);
}

static int nmi_cpu_online(unsigned int cpu)
{
        local_irq_disable();
        if (nmi_enabled)
                nmi_cpu_setup();
        if (ctr_running)
                nmi_cpu_start(NULL);
        local_irq_enable();
        return 0;
}

static int nmi_cpu_down_prep(unsigned int cpu)
{
        local_irq_disable();
        if (ctr_running)
                nmi_cpu_stop(NULL);
        if (nmi_enabled)
                nmi_cpu_shutdown();
        local_irq_enable();
        return 0;
}

static int nmi_create_files(struct dentry *root)
{
        unsigned int i;

        for (i = 0; i < model->num_virt_counters; ++i) {
                struct dentry *dir;
                char buf[4];

                /* quick little hack to _not_ expose a counter if it is not
                 * available for use.  This should protect userspace app.
                 * NOTE:  assumes 1:1 mapping here (that counters are organized
                 *        sequentially in their struct assignment).
                 */
                if (!avail_to_resrv_perfctr_nmi_bit(op_x86_virt_to_phys(i)))
                        continue;

                snprintf(buf,  sizeof(buf), "%d", i);
                dir = oprofilefs_mkdir(root, buf);
                oprofilefs_create_ulong(dir, "enabled", &counter_config[i].enabled);
                oprofilefs_create_ulong(dir, "event", &counter_config[i].event);
                oprofilefs_create_ulong(dir, "count", &counter_config[i].count);
                oprofilefs_create_ulong(dir, "unit_mask", &counter_config[i].unit_mask);
                oprofilefs_create_ulong(dir, "kernel", &counter_config[i].kernel);
                oprofilefs_create_ulong(dir, "user", &counter_config[i].user);
                oprofilefs_create_ulong(dir, "extra", &counter_config[i].extra);
        }

        return 0;
}

static enum cpuhp_state cpuhp_nmi_online;

static int nmi_setup(void)
{
        int err = 0;
        int cpu;

        if (!allocate_msrs())
                return -ENOMEM;

        /* We need to serialize save and setup for HT because the subset
         * of msrs are distinct for save and setup operations
         */

        /* Assume saved/restored counters are the same on all CPUs */
        err = model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
        if (err)
                goto fail;

        for_each_possible_cpu(cpu) {
                if (!IS_ENABLED(CONFIG_SMP) || !cpu)
                        continue;

                memcpy(per_cpu(cpu_msrs, cpu).counters,
                       per_cpu(cpu_msrs, 0).counters,
                       sizeof(struct op_msr) * model->num_counters);

                memcpy(per_cpu(cpu_msrs, cpu).controls,
                       per_cpu(cpu_msrs, 0).controls,
                       sizeof(struct op_msr) * model->num_controls);

                mux_clone(cpu);
        }

        nmi_enabled = 0;
        ctr_running = 0;
        /* make variables visible to the nmi handler: */
        smp_mb();
        err = register_nmi_handler(NMI_LOCAL, profile_exceptions_notify,
                                        0, "oprofile");
        if (err)
                goto fail;

        nmi_enabled = 1;
        /* make nmi_enabled visible to the nmi handler: */
        smp_mb();
        err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/oprofile:online",
                                nmi_cpu_online, nmi_cpu_down_prep);
        if (err < 0)
                goto fail_nmi;
        cpuhp_nmi_online = err;
        return 0;
fail_nmi:
        unregister_nmi_handler(NMI_LOCAL, "oprofile");
fail:
        free_msrs();
        return err;
}

static void nmi_shutdown(void)
{
        struct op_msrs *msrs;

        cpuhp_remove_state(cpuhp_nmi_online);
        nmi_enabled = 0;
        ctr_running = 0;

        /* make variables visible to the nmi handler: */
        smp_mb();
        unregister_nmi_handler(NMI_LOCAL, "oprofile");
        msrs = &get_cpu_var(cpu_msrs);
        model->shutdown(msrs);
        free_msrs();
        put_cpu_var(cpu_msrs);
}

#ifdef CONFIG_PM

static int nmi_suspend(void)
{
        /* Only one CPU left, just stop that one */
        if (nmi_enabled == 1)
                nmi_cpu_stop(NULL);
        return 0;
}

static void nmi_resume(void)
{
        if (nmi_enabled == 1)
                nmi_cpu_start(NULL);
}

static struct syscore_ops oprofile_syscore_ops = {
        .resume         = nmi_resume,
        .suspend        = nmi_suspend,
};

static void __init init_suspend_resume(void)
{
        register_syscore_ops(&oprofile_syscore_ops);
}

static void exit_suspend_resume(void)
{
        unregister_syscore_ops(&oprofile_syscore_ops);
}

#else

static inline void init_suspend_resume(void) { }
static inline void exit_suspend_resume(void) { }

#endif /* CONFIG_PM */

static int __init p4_init(char **cpu_type)
{
        __u8 cpu_model = boot_cpu_data.x86_model;

        if (cpu_model > 6 || cpu_model == 5)
                return 0;

#ifndef CONFIG_SMP
        *cpu_type = "i386/p4";
        model = &op_p4_spec;
        return 1;
#else
        switch (smp_num_siblings) {
        case 1:
                *cpu_type = "i386/p4";
                model = &op_p4_spec;
                return 1;

        case 2:
                *cpu_type = "i386/p4-ht";
                model = &op_p4_ht2_spec;
                return 1;
        }
#endif

        printk(KERN_INFO "oprofile: P4 HyperThreading detected with > 2 threads\n");
        printk(KERN_INFO "oprofile: Reverting to timer mode.\n");
        return 0;
}

enum __force_cpu_type {
        reserved = 0,           /* do not force */
        timer,
        arch_perfmon,
};

static int force_cpu_type;

static int set_cpu_type(const char *str, const struct kernel_param *kp)
{
        if (!strcmp(str, "timer")) {
                force_cpu_type = timer;
                printk(KERN_INFO "oprofile: forcing NMI timer mode\n");
        } else if (!strcmp(str, "arch_perfmon")) {
                force_cpu_type = arch_perfmon;
                printk(KERN_INFO "oprofile: forcing architectural perfmon\n");
        } else {
                force_cpu_type = 0;
        }

        return 0;
}
module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);

static int __init ppro_init(char **cpu_type)
{
        __u8 cpu_model = boot_cpu_data.x86_model;
        struct op_x86_model_spec *spec = &op_ppro_spec; /* default */

        if (force_cpu_type == arch_perfmon && boot_cpu_has(X86_FEATURE_ARCH_PERFMON))
                return 0;

        /*
         * Documentation on identifying Intel processors by CPU family
         * and model can be found in the Intel Software Developer's
         * Manuals (SDM):
         *
         *  http://www.intel.com/products/processor/manuals/
         *
         * As of May 2010 the documentation for this was in the:
         * "Intel 64 and IA-32 Architectures Software Developer's
         * Manual Volume 3B: System Programming Guide", "Table B-1
         * CPUID Signature Values of DisplayFamily_DisplayModel".
         */
        switch (cpu_model) {
        case 0 ... 2:
                *cpu_type = "i386/ppro";
                break;
        case 3 ... 5:
                *cpu_type = "i386/pii";
                break;
        case 6 ... 8:
        case 10 ... 11:
                *cpu_type = "i386/piii";
                break;
        case 9:
        case 13:
                *cpu_type = "i386/p6_mobile";
                break;
        case 14:
                *cpu_type = "i386/core";
                break;
        case 0x0f:
        case 0x16:
        case 0x17:
        case 0x1d:
                *cpu_type = "i386/core_2";
                break;
        case 0x1a:
        case 0x1e:
        case 0x2e:
                spec = &op_arch_perfmon_spec;
                *cpu_type = "i386/core_i7";
                break;
        case 0x1c:
                *cpu_type = "i386/atom";
                break;
        default:
                /* Unknown */
                return 0;
        }

        model = spec;
        return 1;
}

int __init op_nmi_init(struct oprofile_operations *ops)
{
        __u8 vendor = boot_cpu_data.x86_vendor;
        __u8 family = boot_cpu_data.x86;
        char *cpu_type = NULL;
        int ret = 0;

        if (!boot_cpu_has(X86_FEATURE_APIC))
                return -ENODEV;

        if (force_cpu_type == timer)
                return -ENODEV;

        switch (vendor) {
        case X86_VENDOR_AMD:
                /* Needs to be at least an Athlon (or hammer in 32bit mode) */

                switch (family) {
                case 6:
                        cpu_type = "i386/athlon";
                        break;
                case 0xf:
                        /*
                         * Actually it could be i386/hammer too, but
                         * give user space an consistent name.
                         */
                        cpu_type = "x86-64/hammer";
                        break;
                case 0x10:
                        cpu_type = "x86-64/family10";
                        break;
                case 0x11:
                        cpu_type = "x86-64/family11h";
                        break;
                case 0x12:
                        cpu_type = "x86-64/family12h";
                        break;
                case 0x14:
                        cpu_type = "x86-64/family14h";
                        break;
                case 0x15:
                        cpu_type = "x86-64/family15h";
                        break;
                default:
                        return -ENODEV;
                }
                model = &op_amd_spec;
                break;

        case X86_VENDOR_INTEL:
                switch (family) {
                        /* Pentium IV */
                case 0xf:
                        p4_init(&cpu_type);
                        break;

                        /* A P6-class processor */
                case 6:
                        ppro_init(&cpu_type);
                        break;

                default:
                        break;
                }

                if (cpu_type)
                        break;

                if (!boot_cpu_has(X86_FEATURE_ARCH_PERFMON))
                        return -ENODEV;

                /* use arch perfmon as fallback */
                cpu_type = "i386/arch_perfmon";
                model = &op_arch_perfmon_spec;
                break;

        default:
                return -ENODEV;
        }

        /* default values, can be overwritten by model */
        ops->create_files       = nmi_create_files;
        ops->setup              = nmi_setup;
        ops->shutdown           = nmi_shutdown;
        ops->start              = nmi_start;
        ops->stop               = nmi_stop;
        ops->cpu_type           = cpu_type;

        if (model->init)
                ret = model->init(ops);
        if (ret)
                return ret;

        if (!model->num_virt_counters)
                model->num_virt_counters = model->num_counters;

        mux_init(ops);

        init_suspend_resume();

        printk(KERN_INFO "oprofile: using NMI interrupt.\n");
        return 0;
}

void op_nmi_exit(void)
{
        exit_suspend_resume();
}