1 /*
2 * OS info memory interface
3 *
4 * Copyright IBM Corp. 2012
5 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
6 */
7
8 #define KMSG_COMPONENT "os_info"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10
11 #include <linux/crash_dump.h>
12 #include <linux/kernel.h>
13 #include <asm/checksum.h>
14 #include <asm/lowcore.h>
15 #include <asm/os_info.h>
16
17 /*
18 * OS info structure has to be page aligned
19 */
20 static struct os_info os_info __page_aligned_data;
21
22 /*
23 * Compute checksum over OS info structure
24 */
os_info_csum(struct os_info * os_info)25 u32 os_info_csum(struct os_info *os_info)
26 {
27 int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
28 return csum_partial(&os_info->version_major, size, 0);
29 }
30
31 /*
32 * Add crashkernel info to OS info and update checksum
33 */
os_info_crashkernel_add(unsigned long base,unsigned long size)34 void os_info_crashkernel_add(unsigned long base, unsigned long size)
35 {
36 os_info.crashkernel_addr = (u64)(unsigned long)base;
37 os_info.crashkernel_size = (u64)(unsigned long)size;
38 os_info.csum = os_info_csum(&os_info);
39 }
40
41 /*
42 * Add OS info entry and update checksum
43 */
os_info_entry_add(int nr,void * ptr,u64 size)44 void os_info_entry_add(int nr, void *ptr, u64 size)
45 {
46 os_info.entry[nr].addr = (u64)(unsigned long)ptr;
47 os_info.entry[nr].size = size;
48 os_info.entry[nr].csum = csum_partial(ptr, size, 0);
49 os_info.csum = os_info_csum(&os_info);
50 }
51
52 /*
53 * Initialize OS info struture and set lowcore pointer
54 */
os_info_init(void)55 void __init os_info_init(void)
56 {
57 void *ptr = &os_info;
58
59 os_info.version_major = OS_INFO_VERSION_MAJOR;
60 os_info.version_minor = OS_INFO_VERSION_MINOR;
61 os_info.magic = OS_INFO_MAGIC;
62 os_info.csum = os_info_csum(&os_info);
63 copy_to_absolute_zero(&S390_lowcore.os_info, &ptr, sizeof(ptr));
64 }
65
66 #ifdef CONFIG_CRASH_DUMP
67
68 static struct os_info *os_info_old;
69
70 /*
71 * Allocate and copy OS info entry from oldmem
72 */
os_info_old_alloc(int nr,int align)73 static void os_info_old_alloc(int nr, int align)
74 {
75 unsigned long addr, size = 0;
76 char *buf, *buf_align, *msg;
77 u32 csum;
78
79 addr = os_info_old->entry[nr].addr;
80 if (!addr) {
81 msg = "not available";
82 goto fail;
83 }
84 size = os_info_old->entry[nr].size;
85 buf = kmalloc(size + align - 1, GFP_KERNEL);
86 if (!buf) {
87 msg = "alloc failed";
88 goto fail;
89 }
90 buf_align = PTR_ALIGN(buf, align);
91 if (copy_from_oldmem(buf_align, (void *) addr, size)) {
92 msg = "copy failed";
93 goto fail_free;
94 }
95 csum = csum_partial(buf_align, size, 0);
96 if (csum != os_info_old->entry[nr].csum) {
97 msg = "checksum failed";
98 goto fail_free;
99 }
100 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
101 msg = "copied";
102 goto out;
103 fail_free:
104 kfree(buf);
105 fail:
106 os_info_old->entry[nr].addr = 0;
107 out:
108 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
109 nr, msg, addr, size);
110 }
111
112 /*
113 * Initialize os info and os info entries from oldmem
114 */
os_info_old_init(void)115 static void os_info_old_init(void)
116 {
117 static int os_info_init;
118 unsigned long addr;
119
120 if (os_info_init)
121 return;
122 if (!OLDMEM_BASE)
123 goto fail;
124 if (copy_from_oldmem(&addr, &S390_lowcore.os_info, sizeof(addr)))
125 goto fail;
126 if (addr == 0 || addr % PAGE_SIZE)
127 goto fail;
128 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
129 if (!os_info_old)
130 goto fail;
131 if (copy_from_oldmem(os_info_old, (void *) addr, sizeof(*os_info_old)))
132 goto fail_free;
133 if (os_info_old->magic != OS_INFO_MAGIC)
134 goto fail_free;
135 if (os_info_old->csum != os_info_csum(os_info_old))
136 goto fail_free;
137 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
138 goto fail_free;
139 os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
140 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
141 os_info_old_alloc(OS_INFO_INIT_FN, PAGE_SIZE);
142 pr_info("crashkernel: addr=0x%lx size=%lu\n",
143 (unsigned long) os_info_old->crashkernel_addr,
144 (unsigned long) os_info_old->crashkernel_size);
145 os_info_init = 1;
146 return;
147 fail_free:
148 kfree(os_info_old);
149 fail:
150 os_info_init = 1;
151 os_info_old = NULL;
152 }
153
154 /*
155 * Return pointer to os infor entry and its size
156 */
os_info_old_entry(int nr,unsigned long * size)157 void *os_info_old_entry(int nr, unsigned long *size)
158 {
159 os_info_old_init();
160
161 if (!os_info_old)
162 return NULL;
163 if (!os_info_old->entry[nr].addr)
164 return NULL;
165 *size = (unsigned long) os_info_old->entry[nr].size;
166 return (void *)(unsigned long)os_info_old->entry[nr].addr;
167 }
168 #endif
169