lgr.c

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/*
 * Linux Guest Relocation (LGR) detection
 *
 * Copyright IBM Corp. 2012
 * Author(s): Michael Holzheu <[email protected]>
 */

#include <linux/module.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));
    memcpy(&lgr_info->lpar_number, &si->lpar_number,
           sizeof(lgr_info->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(unsigned long ignored)
{
    lgr_info_log();
    lgr_timer_set();
}

static struct timer_list lgr_timer =
    TIMER_DEFERRED_INITIALIZER(lgr_timer_fn, 0, 0);

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

/*
 * 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));
    lgr_timer_set();
    return 0;
}
module_init(lgr_init);