xref: /openbmc/linux/arch/s390/kernel/lgr.c (revision bb0eb050)
1 /*
2  * Linux Guest Relocation (LGR) detection
3  *
4  * Copyright IBM Corp. 2012
5  * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
6  */
7 
8 #include <linux/init.h>
9 #include <linux/export.h>
10 #include <linux/timer.h>
11 #include <linux/slab.h>
12 #include <asm/facility.h>
13 #include <asm/sysinfo.h>
14 #include <asm/ebcdic.h>
15 #include <asm/debug.h>
16 #include <asm/ipl.h>
17 
18 #define LGR_TIMER_INTERVAL_SECS (30 * 60)
19 #define VM_LEVEL_MAX 2 /* Maximum is 8, but we only record two levels */
20 
21 /*
22  * LGR info: Contains stfle and stsi data
23  */
24 struct lgr_info {
25 	/* Bit field with facility information: 4 DWORDs are stored */
26 	u64 stfle_fac_list[4];
27 	/* Level of system (1 = CEC, 2 = LPAR, 3 = z/VM */
28 	u32 level;
29 	/* Level 1: CEC info (stsi 1.1.1) */
30 	char manufacturer[16];
31 	char type[4];
32 	char sequence[16];
33 	char plant[4];
34 	char model[16];
35 	/* Level 2: LPAR info (stsi 2.2.2) */
36 	u16 lpar_number;
37 	char name[8];
38 	/* Level 3: VM info (stsi 3.2.2) */
39 	u8 vm_count;
40 	struct {
41 		char name[8];
42 		char cpi[16];
43 	} vm[VM_LEVEL_MAX];
44 } __packed __aligned(8);
45 
46 /*
47  * LGR globals
48  */
49 static char lgr_page[PAGE_SIZE] __aligned(PAGE_SIZE);
50 static struct lgr_info lgr_info_last;
51 static struct lgr_info lgr_info_cur;
52 static struct debug_info *lgr_dbf;
53 
54 /*
55  * Copy buffer and then convert it to ASCII
56  */
57 static void cpascii(char *dst, char *src, int size)
58 {
59 	memcpy(dst, src, size);
60 	EBCASC(dst, size);
61 }
62 
63 /*
64  * Fill LGR info with 1.1.1 stsi data
65  */
66 static void lgr_stsi_1_1_1(struct lgr_info *lgr_info)
67 {
68 	struct sysinfo_1_1_1 *si = (void *) lgr_page;
69 
70 	if (stsi(si, 1, 1, 1))
71 		return;
72 	cpascii(lgr_info->manufacturer, si->manufacturer,
73 		sizeof(si->manufacturer));
74 	cpascii(lgr_info->type, si->type, sizeof(si->type));
75 	cpascii(lgr_info->model, si->model, sizeof(si->model));
76 	cpascii(lgr_info->sequence, si->sequence, sizeof(si->sequence));
77 	cpascii(lgr_info->plant, si->plant, sizeof(si->plant));
78 }
79 
80 /*
81  * Fill LGR info with 2.2.2 stsi data
82  */
83 static void lgr_stsi_2_2_2(struct lgr_info *lgr_info)
84 {
85 	struct sysinfo_2_2_2 *si = (void *) lgr_page;
86 
87 	if (stsi(si, 2, 2, 2))
88 		return;
89 	cpascii(lgr_info->name, si->name, sizeof(si->name));
90 	memcpy(&lgr_info->lpar_number, &si->lpar_number,
91 	       sizeof(lgr_info->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(unsigned long ignored)
157 {
158 	lgr_info_log();
159 	lgr_timer_set();
160 }
161 
162 static struct timer_list lgr_timer =
163 	TIMER_DEFERRED_INITIALIZER(lgr_timer_fn, 0, 0);
164 
165 /*
166  * Setup next LGR timer
167  */
168 static void lgr_timer_set(void)
169 {
170 	mod_timer(&lgr_timer, jiffies + LGR_TIMER_INTERVAL_SECS * HZ);
171 }
172 
173 /*
174  * Initialize LGR: Add s390dbf, write initial lgr_info and setup timer
175  */
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 	lgr_timer_set();
185 	return 0;
186 }
187 device_initcall(lgr_init);
188