// SPDX-License-Identifier: GPL-2.0
/*
 * Data gathering module for Linux-VM Monitor Stream, Stage 1.
 * Collects misc. OS related data (CPU utilization, running processes).
 *
 * Copyright IBM Corp. 2003, 2006
 *
 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
 */

#define KMSG_COMPONENT  "appldata"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/netdevice.h>
#include <linux/sched.h>
#include <linux/sched/loadavg.h>
#include <linux/sched/stat.h>
#include <asm/appldata.h>
#include <asm/smp.h>

#include "appldata.h"


#define LOAD_INT(x) ((x) >> FSHIFT)
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)

/*
 * OS data
 *
 * This is accessed as binary data by z/VM. If changes to it can't be avoided,
 * the structure version (product ID, see appldata_base.c) needs to be changed
 * as well and all documentation and z/VM applications using it must be
 * updated.
 *
 * The record layout is documented in the Linux for zSeries Device Drivers
 * book:
 * http://oss.software.ibm.com/developerworks/opensource/linux390/index.shtml
 */
struct appldata_os_per_cpu {
        u32 per_cpu_user;       /* timer ticks spent in user mode   */
        u32 per_cpu_nice;       /* ... spent with modified priority */
        u32 per_cpu_system;     /* ... spent in kernel mode         */
        u32 per_cpu_idle;       /* ... spent in idle mode           */

        /* New in 2.6 */
        u32 per_cpu_irq;        /* ... spent in interrupts          */
        u32 per_cpu_softirq;    /* ... spent in softirqs            */
        u32 per_cpu_iowait;     /* ... spent while waiting for I/O  */

        /* New in modification level 01 */
        u32 per_cpu_steal;      /* ... stolen by hypervisor         */
        u32 cpu_id;             /* number of this CPU               */
} __attribute__((packed));

struct appldata_os_data {
        u64 timestamp;
        u32 sync_count_1;       /* after VM collected the record data, */
        u32 sync_count_2;       /* sync_count_1 and sync_count_2 should be the
                                   same. If not, the record has been updated on
                                   the Linux side while VM was collecting the
                                   (possibly corrupt) data */

        u32 nr_cpus;            /* number of (virtual) CPUs        */
        u32 per_cpu_size;       /* size of the per-cpu data struct */
        u32 cpu_offset;         /* offset of the first per-cpu data struct */

        u32 nr_running;         /* number of runnable threads      */
        u32 nr_threads;         /* number of threads               */
        u32 avenrun[3];         /* average nr. of running processes during */
                                /* the last 1, 5 and 15 minutes */

        /* New in 2.6 */
        u32 nr_iowait;          /* number of blocked threads
                                   (waiting for I/O)               */

        /* per cpu data */
        struct appldata_os_per_cpu os_cpu[0];
} __attribute__((packed));

static struct appldata_os_data *appldata_os_data;

static struct appldata_ops ops = {
        .name      = "os",
        .record_nr = APPLDATA_RECORD_OS_ID,
        .owner     = THIS_MODULE,
        .mod_lvl   = {0xF0, 0xF1},              /* EBCDIC "01" */
};


/*
 * appldata_get_os_data()
 *
 * gather OS data
 */
static void appldata_get_os_data(void *data)
{
        int i, j, rc;
        struct appldata_os_data *os_data;
        unsigned int new_size;

        os_data = data;
        os_data->sync_count_1++;

        os_data->nr_threads = nr_threads;
        os_data->nr_running = nr_running();
        os_data->nr_iowait  = nr_iowait();
        os_data->avenrun[0] = avenrun[0] + (FIXED_1/200);
        os_data->avenrun[1] = avenrun[1] + (FIXED_1/200);
        os_data->avenrun[2] = avenrun[2] + (FIXED_1/200);

        j = 0;
        for_each_online_cpu(i) {
                os_data->os_cpu[j].per_cpu_user =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_USER]);
                os_data->os_cpu[j].per_cpu_nice =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_NICE]);
                os_data->os_cpu[j].per_cpu_system =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM]);
                os_data->os_cpu[j].per_cpu_idle =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_IDLE]);
                os_data->os_cpu[j].per_cpu_irq =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_IRQ]);
                os_data->os_cpu[j].per_cpu_softirq =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ]);
                os_data->os_cpu[j].per_cpu_iowait =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_IOWAIT]);
                os_data->os_cpu[j].per_cpu_steal =
                        nsecs_to_jiffies(kcpustat_cpu(i).cpustat[CPUTIME_STEAL]);
                os_data->os_cpu[j].cpu_id = i;
                j++;
        }

        os_data->nr_cpus = j;

        new_size = sizeof(struct appldata_os_data) +
                   (os_data->nr_cpus * sizeof(struct appldata_os_per_cpu));
        if (ops.size != new_size) {
                if (ops.active) {
                        rc = appldata_diag(APPLDATA_RECORD_OS_ID,
                                           APPLDATA_START_INTERVAL_REC,
                                           (unsigned long) ops.data, new_size,
                                           ops.mod_lvl);
                        if (rc != 0)
                                pr_err("Starting a new OS data collection "
                                       "failed with rc=%d\n", rc);

                        rc = appldata_diag(APPLDATA_RECORD_OS_ID,
                                           APPLDATA_STOP_REC,
                                           (unsigned long) ops.data, ops.size,
                                           ops.mod_lvl);
                        if (rc != 0)
                                pr_err("Stopping a faulty OS data "
                                       "collection failed with rc=%d\n", rc);
                }
                ops.size = new_size;
        }
        os_data->timestamp = get_tod_clock();
        os_data->sync_count_2++;
}


/*
 * appldata_os_init()
 *
 * init data, register ops
 */
static int __init appldata_os_init(void)
{
        int rc, max_size;

        max_size = sizeof(struct appldata_os_data) +
                   (num_possible_cpus() * sizeof(struct appldata_os_per_cpu));
        if (max_size > APPLDATA_MAX_REC_SIZE) {
                pr_err("Maximum OS record size %i exceeds the maximum "
                       "record size %i\n", max_size, APPLDATA_MAX_REC_SIZE);
                rc = -ENOMEM;
                goto out;
        }

        appldata_os_data = kzalloc(max_size, GFP_KERNEL | GFP_DMA);
        if (appldata_os_data == NULL) {
                rc = -ENOMEM;
                goto out;
        }

        appldata_os_data->per_cpu_size = sizeof(struct appldata_os_per_cpu);
        appldata_os_data->cpu_offset   = offsetof(struct appldata_os_data,
                                                        os_cpu);

        ops.data = appldata_os_data;
        ops.callback  = &appldata_get_os_data;
        rc = appldata_register_ops(&ops);
        if (rc != 0)
                kfree(appldata_os_data);
out:
        return rc;
}

/*
 * appldata_os_exit()
 *
 * unregister ops
 */
static void __exit appldata_os_exit(void)
{
        appldata_unregister_ops(&ops);
        kfree(appldata_os_data);
}


module_init(appldata_os_init);
module_exit(appldata_os_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Gerald Schaefer");
MODULE_DESCRIPTION("Linux-VM Monitor Stream, OS statistics");