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root/arch/x86/oprofile/nmi_int.c

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DEFINITIONS

This source file includes following definitions.
  1. oprofile_cpu_notifier
  2. nmi_suspend
  3. nmi_resume
  4. init_sysfs
  5. exit_sysfs
  6. profile_exceptions_notify
  7. nmi_cpu_save_registers
  8. nmi_save_registers
  9. free_msrs
  10. allocate_msrs
  11. nmi_cpu_setup
  12. nmi_setup
  13. nmi_restore_registers
  14. nmi_cpu_shutdown
  15. nmi_shutdown
  16. nmi_cpu_start
  17. nmi_start
  18. nmi_cpu_stop
  19. nmi_stop
  20. nmi_create_files
  21. p4_init
  22. ppro_init
  23. op_nmi_init
  24. op_nmi_exit

/**
 * @file nmi_int.c
 *
 * @remark Copyright 2002-2008 OProfile authors
 * @remark Read the file COPYING
 *
 * @author John Levon <levon@movementarian.org>
 * @author Robert Richter <robert.richter@amd.com>
 */

#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#include <linux/oprofile.h>
#include <linux/sysdev.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 const *model;
static DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
static DEFINE_PER_CPU(unsigned long, saved_lvtpc);

static int nmi_start(void);
static void nmi_stop(void);
static void nmi_cpu_start(void *dummy);
static void nmi_cpu_stop(void *dummy);

/* 0 == registered but off, 1 == registered and on */
static int nmi_enabled = 0;

#ifdef CONFIG_SMP
static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
                                 void *data)
{
        int cpu = (unsigned long)data;
        switch (action) {
        case CPU_DOWN_FAILED:
        case CPU_ONLINE:
                smp_call_function_single(cpu, nmi_cpu_start, NULL, 0);
                break;
        case CPU_DOWN_PREPARE:
                smp_call_function_single(cpu, nmi_cpu_stop, NULL, 1);
                break;
        }
        return NOTIFY_DONE;
}

static struct notifier_block oprofile_cpu_nb = {
        .notifier_call = oprofile_cpu_notifier
};
#endif

#ifdef CONFIG_PM

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

static int nmi_resume(struct sys_device *dev)
{
        if (nmi_enabled == 1)
                nmi_cpu_start(NULL);
        return 0;
}

static struct sysdev_class oprofile_sysclass = {
        .name           = "oprofile",
        .resume         = nmi_resume,
        .suspend        = nmi_suspend,
};

static struct sys_device device_oprofile = {
        .id     = 0,
        .cls    = &oprofile_sysclass,
};

static int __init init_sysfs(void)
{
        int error;

        error = sysdev_class_register(&oprofile_sysclass);
        if (!error)
                error = sysdev_register(&device_oprofile);
        return error;
}

static void exit_sysfs(void)
{
        sysdev_unregister(&device_oprofile);
        sysdev_class_unregister(&oprofile_sysclass);
}

#else
#define init_sysfs() do { } while (0)
#define exit_sysfs() do { } while (0)
#endif /* CONFIG_PM */

static int profile_exceptions_notify(struct notifier_block *self,
                                     unsigned long val, void *data)
{
        struct die_args *args = (struct die_args *)data;
        int ret = NOTIFY_DONE;
        int cpu = smp_processor_id();

        switch (val) {
        case DIE_NMI:
                if (model->check_ctrs(args->regs, &per_cpu(cpu_msrs, cpu)))
                        ret = NOTIFY_STOP;
                break;
        default:
                break;
        }
        return ret;
}

static void nmi_cpu_save_registers(struct op_msrs *msrs)
{
        unsigned int const nr_ctrs = model->num_counters;
        unsigned int const nr_ctrls = model->num_controls;
        struct op_msr *counters = msrs->counters;
        struct op_msr *controls = msrs->controls;
        unsigned int i;

        for (i = 0; i < nr_ctrs; ++i) {
                if (counters[i].addr) {
                        rdmsr(counters[i].addr,
                                counters[i].saved.low,
                                counters[i].saved.high);
                }
        }

        for (i = 0; i < nr_ctrls; ++i) {
                if (controls[i].addr) {
                        rdmsr(controls[i].addr,
                                controls[i].saved.low,
                                controls[i].saved.high);
                }
        }
}

static void nmi_save_registers(void *dummy)
{
        int cpu = smp_processor_id();
        struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
        nmi_cpu_save_registers(msrs);
}

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;
        }
}

static int allocate_msrs(void)
{
        int success = 1;
        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 = kmalloc(counters_size,
                                                                GFP_KERNEL);
                if (!per_cpu(cpu_msrs, i).counters) {
                        success = 0;
                        break;
                }
                per_cpu(cpu_msrs, i).controls = kmalloc(controls_size,
                                                                GFP_KERNEL);
                if (!per_cpu(cpu_msrs, i).controls) {
                        success = 0;
                        break;
                }
        }

        if (!success)
                free_msrs();

        return success;
}

static void nmi_cpu_setup(void *dummy)
{
        int cpu = smp_processor_id();
        struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
        spin_lock(&oprofilefs_lock);
        model->setup_ctrs(msrs);
        spin_unlock(&oprofilefs_lock);
        per_cpu(saved_lvtpc, cpu) = apic_read(APIC_LVTPC);
        apic_write(APIC_LVTPC, APIC_DM_NMI);
}

static struct notifier_block profile_exceptions_nb = {
        .notifier_call = profile_exceptions_notify,
        .next = NULL,
        .priority = 0
};

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

        if (!allocate_msrs())
                return -ENOMEM;

        err = register_die_notifier(&profile_exceptions_nb);
        if (err) {
                free_msrs();
                return err;
        }

        /* 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 */
        model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
        for_each_possible_cpu(cpu) {
                if (cpu != 0) {
                        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);
                }

        }
        on_each_cpu(nmi_save_registers, NULL, 1);
        on_each_cpu(nmi_cpu_setup, NULL, 1);
        nmi_enabled = 1;
        return 0;
}

static void nmi_restore_registers(struct op_msrs *msrs)
{
        unsigned int const nr_ctrs = model->num_counters;
        unsigned int const nr_ctrls = model->num_controls;
        struct op_msr *counters = msrs->counters;
        struct op_msr *controls = msrs->controls;
        unsigned int i;

        for (i = 0; i < nr_ctrls; ++i) {
                if (controls[i].addr) {
                        wrmsr(controls[i].addr,
                                controls[i].saved.low,
                                controls[i].saved.high);
                }
        }

        for (i = 0; i < nr_ctrs; ++i) {
                if (counters[i].addr) {
                        wrmsr(counters[i].addr,
                                counters[i].saved.low,
                                counters[i].saved.high);
                }
        }
}

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

        /* 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_restore_registers(msrs);
}

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

        nmi_enabled = 0;
        on_each_cpu(nmi_cpu_shutdown, NULL, 1);
        unregister_die_notifier(&profile_exceptions_nb);
        msrs = &get_cpu_var(cpu_msrs);
        model->shutdown(msrs);
        free_msrs();
        put_cpu_var(cpu_msrs);
}

static void nmi_cpu_start(void *dummy)
{
        struct op_msrs const *msrs = &__get_cpu_var(cpu_msrs);
        model->start(msrs);
}

static int nmi_start(void)
{
        on_each_cpu(nmi_cpu_start, NULL, 1);
        return 0;
}

static void nmi_cpu_stop(void *dummy)
{
        struct op_msrs const *msrs = &__get_cpu_var(cpu_msrs);
        model->stop(msrs);
}

static void nmi_stop(void)
{
        on_each_cpu(nmi_cpu_stop, NULL, 1);
}

struct op_counter_config counter_config[OP_MAX_COUNTER];

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

        for (i = 0; i < model->num_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 (unlikely(!avail_to_resrv_perfctr_nmi_bit(i)))
                        continue;

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

        return 0;
}

static int p4force;
module_param(p4force, int, 0);

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

        if (!p4force && (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;
}

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

        switch (cpu_model) {
        case 0 ... 2:
                *cpu_type = "i386/ppro";
                break;
        case 3 ... 5:
                *cpu_type = "i386/pii";
                break;
        case 6 ... 8:
                *cpu_type = "i386/piii";
                break;
        case 9:
                *cpu_type = "i386/p6_mobile";
                break;
        case 10 ... 13:
                *cpu_type = "i386/p6";
                break;
        case 14:
                *cpu_type = "i386/core";
                break;
        case 15: case 23:
                *cpu_type = "i386/core_2";
                break;
        case 26:
                *cpu_type = "i386/core_2";
                break;
        default:
                /* Unknown */
                return 0;
        }

        model = &op_ppro_spec;
        return 1;
}

/* in order to get sysfs right */
static int using_nmi;

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;
        int ret = 0;

        if (!cpu_has_apic)
                return -ENODEV;

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

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

        case X86_VENDOR_INTEL:
                switch (family) {
                        /* Pentium IV */
                case 0xf:
                        if (!p4_init(&cpu_type))
                                return -ENODEV;
                        break;

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

                default:
                        return -ENODEV;
                }
                break;

        default:
                return -ENODEV;
        }

#ifdef CONFIG_SMP
        register_cpu_notifier(&oprofile_cpu_nb);
#endif
        /* 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;

        init_sysfs();
        using_nmi = 1;
        printk(KERN_INFO "oprofile: using NMI interrupt.\n");
        return 0;
}

void op_nmi_exit(void)
{
        if (using_nmi) {
                exit_sysfs();
#ifdef CONFIG_SMP
                unregister_cpu_notifier(&oprofile_cpu_nb);
#endif
        }
        if (model->exit)
                model->exit();
}

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