linux/arch/s390/kernel/lgr.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Linux Guest Relocation (LGR) detection
   4 *
   5 * Copyright IBM Corp. 2012
   6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
   7 */
   8
   9#include <linux/init.h>
  10#include <linux/export.h>
  11#include <linux/timer.h>
  12#include <linux/slab.h>
  13#include <asm/facility.h>
  14#include <asm/sysinfo.h>
  15#include <asm/ebcdic.h>
  16#include <asm/debug.h>
  17#include <asm/ipl.h>
  18
  19#define LGR_TIMER_INTERVAL_SECS (30 * 60)
  20#define VM_LEVEL_MAX 2 /* Maximum is 8, but we only record two levels */
  21
  22/*
  23 * LGR info: Contains stfle and stsi data
  24 */
  25struct lgr_info {
  26        /* Bit field with facility information: 4 DWORDs are stored */
  27        u64 stfle_fac_list[4];
  28        /* Level of system (1 = CEC, 2 = LPAR, 3 = z/VM */
  29        u32 level;
  30        /* Level 1: CEC info (stsi 1.1.1) */
  31        char manufacturer[16];
  32        char type[4];
  33        char sequence[16];
  34        char plant[4];
  35        char model[16];
  36        /* Level 2: LPAR info (stsi 2.2.2) */
  37        u16 lpar_number;
  38        char name[8];
  39        /* Level 3: VM info (stsi 3.2.2) */
  40        u8 vm_count;
  41        struct {
  42                char name[8];
  43                char cpi[16];
  44        } vm[VM_LEVEL_MAX];
  45} __packed __aligned(8);
  46
  47/*
  48 * LGR globals
  49 */
  50static char lgr_page[PAGE_SIZE] __aligned(PAGE_SIZE);
  51static struct lgr_info lgr_info_last;
  52static struct lgr_info lgr_info_cur;
  53static struct debug_info *lgr_dbf;
  54
  55/*
  56 * Copy buffer and then convert it to ASCII
  57 */
  58static void cpascii(char *dst, char *src, int size)
  59{
  60        memcpy(dst, src, size);
  61        EBCASC(dst, size);
  62}
  63
  64/*
  65 * Fill LGR info with 1.1.1 stsi data
  66 */
  67static void lgr_stsi_1_1_1(struct lgr_info *lgr_info)
  68{
  69        struct sysinfo_1_1_1 *si = (void *) lgr_page;
  70
  71        if (stsi(si, 1, 1, 1))
  72                return;
  73        cpascii(lgr_info->manufacturer, si->manufacturer,
  74                sizeof(si->manufacturer));
  75        cpascii(lgr_info->type, si->type, sizeof(si->type));
  76        cpascii(lgr_info->model, si->model, sizeof(si->model));
  77        cpascii(lgr_info->sequence, si->sequence, sizeof(si->sequence));
  78        cpascii(lgr_info->plant, si->plant, sizeof(si->plant));
  79}
  80
  81/*
  82 * Fill LGR info with 2.2.2 stsi data
  83 */
  84static void lgr_stsi_2_2_2(struct lgr_info *lgr_info)
  85{
  86        struct sysinfo_2_2_2 *si = (void *) lgr_page;
  87
  88        if (stsi(si, 2, 2, 2))
  89                return;
  90        cpascii(lgr_info->name, si->name, sizeof(si->name));
  91        memcpy(&lgr_info->lpar_number, &si->lpar_number,
  92               sizeof(lgr_info->lpar_number));
  93}
  94
  95/*
  96 * Fill LGR info with 3.2.2 stsi data
  97 */
  98static void lgr_stsi_3_2_2(struct lgr_info *lgr_info)
  99{
 100        struct sysinfo_3_2_2 *si = (void *) lgr_page;
 101        int i;
 102
 103        if (stsi(si, 3, 2, 2))
 104                return;
 105        for (i = 0; i < min_t(u8, si->count, VM_LEVEL_MAX); i++) {
 106                cpascii(lgr_info->vm[i].name, si->vm[i].name,
 107                        sizeof(si->vm[i].name));
 108                cpascii(lgr_info->vm[i].cpi, si->vm[i].cpi,
 109                        sizeof(si->vm[i].cpi));
 110        }
 111        lgr_info->vm_count = si->count;
 112}
 113
 114/*
 115 * Fill LGR info with current data
 116 */
 117static void lgr_info_get(struct lgr_info *lgr_info)
 118{
 119        int level;
 120
 121        memset(lgr_info, 0, sizeof(*lgr_info));
 122        stfle(lgr_info->stfle_fac_list, ARRAY_SIZE(lgr_info->stfle_fac_list));
 123        level = stsi(NULL, 0, 0, 0);
 124        lgr_info->level = level;
 125        if (level >= 1)
 126                lgr_stsi_1_1_1(lgr_info);
 127        if (level >= 2)
 128                lgr_stsi_2_2_2(lgr_info);
 129        if (level >= 3)
 130                lgr_stsi_3_2_2(lgr_info);
 131}
 132
 133/*
 134 * Check if LGR info has changed and if yes log new LGR info to s390dbf
 135 */
 136void lgr_info_log(void)
 137{
 138        static DEFINE_SPINLOCK(lgr_info_lock);
 139        unsigned long flags;
 140
 141        if (!spin_trylock_irqsave(&lgr_info_lock, flags))
 142                return;
 143        lgr_info_get(&lgr_info_cur);
 144        if (memcmp(&lgr_info_last, &lgr_info_cur, sizeof(lgr_info_cur)) != 0) {
 145                debug_event(lgr_dbf, 1, &lgr_info_cur, sizeof(lgr_info_cur));
 146                lgr_info_last = lgr_info_cur;
 147        }
 148        spin_unlock_irqrestore(&lgr_info_lock, flags);
 149}
 150EXPORT_SYMBOL_GPL(lgr_info_log);
 151
 152static void lgr_timer_set(void);
 153
 154/*
 155 * LGR timer callback
 156 */
 157static void lgr_timer_fn(struct timer_list *unused)
 158{
 159        lgr_info_log();
 160        lgr_timer_set();
 161}
 162
 163static struct timer_list lgr_timer;
 164
 165/*
 166 * Setup next LGR timer
 167 */
 168static void lgr_timer_set(void)
 169{
 170        mod_timer(&lgr_timer, jiffies + msecs_to_jiffies(LGR_TIMER_INTERVAL_SECS * MSEC_PER_SEC));
 171}
 172
 173/*
 174 * Initialize LGR: Add s390dbf, write initial lgr_info and setup timer
 175 */
 176static int __init lgr_init(void)
 177{
 178        lgr_dbf = debug_register("lgr", 1, 1, sizeof(struct lgr_info));
 179        if (!lgr_dbf)
 180                return -ENOMEM;
 181        debug_register_view(lgr_dbf, &debug_hex_ascii_view);
 182        lgr_info_get(&lgr_info_last);
 183        debug_event(lgr_dbf, 1, &lgr_info_last, sizeof(lgr_info_last));
 184        timer_setup(&lgr_timer, lgr_timer_fn, TIMER_DEFERRABLE);
 185        lgr_timer_set();
 186        return 0;
 187}
 188device_initcall(lgr_init);
 189
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