xref: /openbmc/linux/arch/s390/kernel/lgr.c (revision 0a94608f)
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  */
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  */
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  */
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 	lgr_info->lpar_number = si->lpar_number;
92 }
93 
94 /*
95  * Fill LGR info with 3.2.2 stsi data
96  */
97 static 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  */
116 static 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  */
135 void 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 }
149 EXPORT_SYMBOL_GPL(lgr_info_log);
150 
151 static void lgr_timer_set(void);
152 
153 /*
154  * LGR timer callback
155  */
156 static void lgr_timer_fn(struct timer_list *unused)
157 {
158 	lgr_info_log();
159 	lgr_timer_set();
160 }
161 
162 static struct timer_list lgr_timer;
163 
164 /*
165  * Setup next LGR timer
166  */
167 static 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  */
175 static 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 }
187 device_initcall(lgr_init);
188