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  */
25 struct 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  */
50 static char lgr_page[PAGE_SIZE] __aligned(PAGE_SIZE);
51 static struct lgr_info lgr_info_last;
52 static struct lgr_info lgr_info_cur;
53 static struct debug_info *lgr_dbf;
54 
55 /*
56  * Copy buffer and then convert it to ASCII
57  */
cpascii(char * dst,char * src,int size)58 static 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  */
lgr_stsi_1_1_1(struct lgr_info * lgr_info)67 static 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  */
lgr_stsi_2_2_2(struct lgr_info * lgr_info)84 static 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  */
lgr_stsi_3_2_2(struct lgr_info * lgr_info)98 static 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  */
lgr_info_get(struct lgr_info * lgr_info)117 static 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  */
lgr_info_log(void)136 void 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 }
150 EXPORT_SYMBOL_GPL(lgr_info_log);
151 
152 static void lgr_timer_set(void);
153 
154 /*
155  * LGR timer callback
156  */
lgr_timer_fn(struct timer_list * unused)157 static void lgr_timer_fn(struct timer_list *unused)
158 {
159 	lgr_info_log();
160 	lgr_timer_set();
161 }
162 
163 static struct timer_list lgr_timer;
164 
165 /*
166  * Setup next LGR timer
167  */
lgr_timer_set(void)168 static 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  */
lgr_init(void)176 static 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 }
188 device_initcall(lgr_init);
189