cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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lgr.c (4393B)

      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	lgr_info->lpar_number = si->lpar_number;
     92}
     93
     94/*
     95 * Fill LGR info with 3.2.2 stsi data
     96 */
     97static void lgr_stsi_3_2_2(struct lgr_info *lgr_info)
     98{
     99	struct sysinfo_3_2_2 *si = (void *) lgr_page;
    100	int i;
    101
    102	if (stsi(si, 3, 2, 2))
    103		return;
    104	for (i = 0; i < min_t(u8, si->count, VM_LEVEL_MAX); i++) {
    105		cpascii(lgr_info->vm[i].name, si->vm[i].name,
    106			sizeof(si->vm[i].name));
    107		cpascii(lgr_info->vm[i].cpi, si->vm[i].cpi,
    108			sizeof(si->vm[i].cpi));
    109	}
    110	lgr_info->vm_count = si->count;
    111}
    112
    113/*
    114 * Fill LGR info with current data
    115 */
    116static void lgr_info_get(struct lgr_info *lgr_info)
    117{
    118	int level;
    119
    120	memset(lgr_info, 0, sizeof(*lgr_info));
    121	stfle(lgr_info->stfle_fac_list, ARRAY_SIZE(lgr_info->stfle_fac_list));
    122	level = stsi(NULL, 0, 0, 0);
    123	lgr_info->level = level;
    124	if (level >= 1)
    125		lgr_stsi_1_1_1(lgr_info);
    126	if (level >= 2)
    127		lgr_stsi_2_2_2(lgr_info);
    128	if (level >= 3)
    129		lgr_stsi_3_2_2(lgr_info);
    130}
    131
    132/*
    133 * Check if LGR info has changed and if yes log new LGR info to s390dbf
    134 */
    135void lgr_info_log(void)
    136{
    137	static DEFINE_SPINLOCK(lgr_info_lock);
    138	unsigned long flags;
    139
    140	if (!spin_trylock_irqsave(&lgr_info_lock, flags))
    141		return;
    142	lgr_info_get(&lgr_info_cur);
    143	if (memcmp(&lgr_info_last, &lgr_info_cur, sizeof(lgr_info_cur)) != 0) {
    144		debug_event(lgr_dbf, 1, &lgr_info_cur, sizeof(lgr_info_cur));
    145		lgr_info_last = lgr_info_cur;
    146	}
    147	spin_unlock_irqrestore(&lgr_info_lock, flags);
    148}
    149EXPORT_SYMBOL_GPL(lgr_info_log);
    150
    151static void lgr_timer_set(void);
    152
    153/*
    154 * LGR timer callback
    155 */
    156static void lgr_timer_fn(struct timer_list *unused)
    157{
    158	lgr_info_log();
    159	lgr_timer_set();
    160}
    161
    162static struct timer_list lgr_timer;
    163
    164/*
    165 * Setup next LGR timer
    166 */
    167static void lgr_timer_set(void)
    168{
    169	mod_timer(&lgr_timer, jiffies + msecs_to_jiffies(LGR_TIMER_INTERVAL_SECS * MSEC_PER_SEC));
    170}
    171
    172/*
    173 * Initialize LGR: Add s390dbf, write initial lgr_info and setup timer
    174 */
    175static int __init lgr_init(void)
    176{
    177	lgr_dbf = debug_register("lgr", 1, 1, sizeof(struct lgr_info));
    178	if (!lgr_dbf)
    179		return -ENOMEM;
    180	debug_register_view(lgr_dbf, &debug_hex_ascii_view);
    181	lgr_info_get(&lgr_info_last);
    182	debug_event(lgr_dbf, 1, &lgr_info_last, sizeof(lgr_info_last));
    183	timer_setup(&lgr_timer, lgr_timer_fn, TIMER_DEFERRABLE);
    184	lgr_timer_set();
    185	return 0;
    186}
    187device_initcall(lgr_init);