// SPDX-License-Identifier: GPL-2.0
/*
 * Linux Guest Relocation (LGR) detection
 *
 * Copyright IBM Corp. 2012
 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
 */

#include <linux/init.h>
#include <linux/export.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <asm/facility.h>
#include <asm/sysinfo.h>
#include <asm/ebcdic.h>
#include <asm/debug.h>
#include <asm/ipl.h>

#define LGR_TIMER_INTERVAL_SECS (30 * 60)
#define VM_LEVEL_MAX 2 /* Maximum is 8, but we only record two levels */

/*
 * LGR info: Contains stfle and stsi data
 */
struct lgr_info {
        /* Bit field with facility information: 4 DWORDs are stored */
        u64 stfle_fac_list[4];
        /* Level of system (1 = CEC, 2 = LPAR, 3 = z/VM */
        u32 level;
        /* Level 1: CEC info (stsi 1.1.1) */
        char manufacturer[16];
        char type[4];
        char sequence[16];
        char plant[4];
        char model[16];
        /* Level 2: LPAR info (stsi 2.2.2) */
        u16 lpar_number;
        char name[8];
        /* Level 3: VM info (stsi 3.2.2) */
        u8 vm_count;
        struct {
                char name[8];
                char cpi[16];
        } vm[VM_LEVEL_MAX];
} __packed __aligned(8);

/*
 * LGR globals
 */
static char lgr_page[PAGE_SIZE] __aligned(PAGE_SIZE);
static struct lgr_info lgr_info_last;
static struct lgr_info lgr_info_cur;
static struct debug_info *lgr_dbf;

/*
 * Copy buffer and then convert it to ASCII
 */
static void cpascii(char *dst, char *src, int size)
{
        memcpy(dst, src, size);
        EBCASC(dst, size);
}

/*
 * Fill LGR info with 1.1.1 stsi data
 */
static void lgr_stsi_1_1_1(struct lgr_info *lgr_info)
{
        struct sysinfo_1_1_1 *si = (void *) lgr_page;

        if (stsi(si, 1, 1, 1))
                return;
        cpascii(lgr_info->manufacturer, si->manufacturer,
                sizeof(si->manufacturer));
        cpascii(lgr_info->type, si->type, sizeof(si->type));
        cpascii(lgr_info->model, si->model, sizeof(si->model));
        cpascii(lgr_info->sequence, si->sequence, sizeof(si->sequence));
        cpascii(lgr_info->plant, si->plant, sizeof(si->plant));
}

/*
 * Fill LGR info with 2.2.2 stsi data
 */
static void lgr_stsi_2_2_2(struct lgr_info *lgr_info)
{
        struct sysinfo_2_2_2 *si = (void *) lgr_page;

        if (stsi(si, 2, 2, 2))
                return;
        cpascii(lgr_info->name, si->name, sizeof(si->name));
        lgr_info->lpar_number = si->lpar_number;
}

/*
 * Fill LGR info with 3.2.2 stsi data
 */
static void lgr_stsi_3_2_2(struct lgr_info *lgr_info)
{
        struct sysinfo_3_2_2 *si = (void *) lgr_page;
        int i;

        if (stsi(si, 3, 2, 2))
                return;
        for (i = 0; i < min_t(u8, si->count, VM_LEVEL_MAX); i++) {
                cpascii(lgr_info->vm[i].name, si->vm[i].name,
                        sizeof(si->vm[i].name));
                cpascii(lgr_info->vm[i].cpi, si->vm[i].cpi,
                        sizeof(si->vm[i].cpi));
        }
        lgr_info->vm_count = si->count;
}

/*
 * Fill LGR info with current data
 */
static void lgr_info_get(struct lgr_info *lgr_info)
{
        int level;

        memset(lgr_info, 0, sizeof(*lgr_info));
        stfle(lgr_info->stfle_fac_list, ARRAY_SIZE(lgr_info->stfle_fac_list));
        level = stsi(NULL, 0, 0, 0);
        lgr_info->level = level;
        if (level >= 1)
                lgr_stsi_1_1_1(lgr_info);
        if (level >= 2)
                lgr_stsi_2_2_2(lgr_info);
        if (level >= 3)
                lgr_stsi_3_2_2(lgr_info);
}

/*
 * Check if LGR info has changed and if yes log new LGR info to s390dbf
 */
void lgr_info_log(void)
{
        static DEFINE_SPINLOCK(lgr_info_lock);
        unsigned long flags;

        if (!spin_trylock_irqsave(&lgr_info_lock, flags))
                return;
        lgr_info_get(&lgr_info_cur);
        if (memcmp(&lgr_info_last, &lgr_info_cur, sizeof(lgr_info_cur)) != 0) {
                debug_event(lgr_dbf, 1, &lgr_info_cur, sizeof(lgr_info_cur));
                lgr_info_last = lgr_info_cur;
        }
        spin_unlock_irqrestore(&lgr_info_lock, flags);
}
EXPORT_SYMBOL_GPL(lgr_info_log);

static void lgr_timer_set(void);

/*
 * LGR timer callback
 */
static void lgr_timer_fn(struct timer_list *unused)
{
        lgr_info_log();
        lgr_timer_set();
}

static struct timer_list lgr_timer;

/*
 * Setup next LGR timer
 */
static void lgr_timer_set(void)
{
        mod_timer(&lgr_timer, jiffies + secs_to_jiffies(LGR_TIMER_INTERVAL_SECS));
}

/*
 * Initialize LGR: Add s390dbf, write initial lgr_info and setup timer
 */
static int __init lgr_init(void)
{
        lgr_dbf = debug_register("lgr", 1, 1, sizeof(struct lgr_info));
        if (!lgr_dbf)
                return -ENOMEM;
        debug_register_view(lgr_dbf, &debug_hex_ascii_view);
        lgr_info_get(&lgr_info_last);
        debug_event(lgr_dbf, 1, &lgr_info_last, sizeof(lgr_info_last));
        timer_setup(&lgr_timer, lgr_timer_fn, TIMER_DEFERRABLE);
        lgr_timer_set();
        return 0;
}
device_initcall(lgr_init);