summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/os_info.c
blob: 753ba63182b966eced22c3723e7c263077ed72ed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
/*
 * OS info memory interface
 *
 * Copyright IBM Corp. 2012
 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
 */

#define KMSG_COMPONENT "os_info"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/crash_dump.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <asm/checksum.h>
#include <asm/lowcore.h>
#include <asm/os_info.h>

/*
 * OS info structure has to be page aligned
 */
static struct os_info os_info __page_aligned_data;

/*
 * Compute checksum over OS info structure
 */
u32 os_info_csum(struct os_info *os_info)
{
	int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
	return (__force u32)csum_partial(&os_info->version_major, size, 0);
}

/*
 * Add crashkernel info to OS info and update checksum
 */
void os_info_crashkernel_add(unsigned long base, unsigned long size)
{
	os_info.crashkernel_addr = (u64)(unsigned long)base;
	os_info.crashkernel_size = (u64)(unsigned long)size;
	os_info.csum = os_info_csum(&os_info);
}

/*
 * Add OS info entry and update checksum
 */
void os_info_entry_add(int nr, void *ptr, u64 size)
{
	os_info.entry[nr].addr = (u64)(unsigned long)ptr;
	os_info.entry[nr].size = size;
	os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
	os_info.csum = os_info_csum(&os_info);
}

/*
 * Initialize OS info struture and set lowcore pointer
 */
void __init os_info_init(void)
{
	void *ptr = &os_info;

	os_info.version_major = OS_INFO_VERSION_MAJOR;
	os_info.version_minor = OS_INFO_VERSION_MINOR;
	os_info.magic = OS_INFO_MAGIC;
	os_info.csum = os_info_csum(&os_info);
	mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
}

#ifdef CONFIG_CRASH_DUMP

static struct os_info *os_info_old;

/*
 * Allocate and copy OS info entry from oldmem
 */
static void os_info_old_alloc(int nr, int align)
{
	unsigned long addr, size = 0;
	char *buf, *buf_align, *msg;
	u32 csum;

	addr = os_info_old->entry[nr].addr;
	if (!addr) {
		msg = "not available";
		goto fail;
	}
	size = os_info_old->entry[nr].size;
	buf = kmalloc(size + align - 1, GFP_KERNEL);
	if (!buf) {
		msg = "alloc failed";
		goto fail;
	}
	buf_align = PTR_ALIGN(buf, align);
	if (copy_oldmem_kernel(buf_align, (void *) addr, size)) {
		msg = "copy failed";
		goto fail_free;
	}
	csum = (__force u32)csum_partial(buf_align, size, 0);
	if (csum != os_info_old->entry[nr].csum) {
		msg = "checksum failed";
		goto fail_free;
	}
	os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
	msg = "copied";
	goto out;
fail_free:
	kfree(buf);
fail:
	os_info_old->entry[nr].addr = 0;
out:
	pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
		nr, msg, addr, size);
}

/*
 * Initialize os info and os info entries from oldmem
 */
static void os_info_old_init(void)
{
	static int os_info_init;
	unsigned long addr;

	if (os_info_init)
		return;
	if (!OLDMEM_BASE)
		goto fail;
	if (copy_oldmem_kernel(&addr, &S390_lowcore.os_info, sizeof(addr)))
		goto fail;
	if (addr == 0 || addr % PAGE_SIZE)
		goto fail;
	os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
	if (!os_info_old)
		goto fail;
	if (copy_oldmem_kernel(os_info_old, (void *) addr,
			       sizeof(*os_info_old)))
		goto fail_free;
	if (os_info_old->magic != OS_INFO_MAGIC)
		goto fail_free;
	if (os_info_old->csum != os_info_csum(os_info_old))
		goto fail_free;
	if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
		goto fail_free;
	os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
	os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
	pr_info("crashkernel: addr=0x%lx size=%lu\n",
		(unsigned long) os_info_old->crashkernel_addr,
		(unsigned long) os_info_old->crashkernel_size);
	os_info_init = 1;
	return;
fail_free:
	kfree(os_info_old);
fail:
	os_info_init = 1;
	os_info_old = NULL;
}

/*
 * Return pointer to os infor entry and its size
 */
void *os_info_old_entry(int nr, unsigned long *size)
{
	os_info_old_init();

	if (!os_info_old)
		return NULL;
	if (!os_info_old->entry[nr].addr)
		return NULL;
	*size = (unsigned long) os_info_old->entry[nr].size;
	return (void *)(unsigned long)os_info_old->entry[nr].addr;
}
#endif