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 <linux/slab.h>
14 #include <asm/checksum.h>
15 #include <asm/lowcore.h>
16 #include <asm/os_info.h>
17
18 /*
19 * OS info structure has to be page aligned
20 */
21 static struct os_info os_info __page_aligned_data;
22
23 /*
24 * Compute checksum over OS info structure
25 */
os_info_csum(struct os_info * os_info)26 u32 os_info_csum(struct os_info *os_info)
27 {
28 int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
29 return csum_partial(&os_info->version_major, size, 0);
30 }
31
32 /*
33 * Add crashkernel info to OS info and update checksum
34 */
os_info_crashkernel_add(unsigned long base,unsigned long size)35 void os_info_crashkernel_add(unsigned long base, unsigned long size)
36 {
37 os_info.crashkernel_addr = (u64)(unsigned long)base;
38 os_info.crashkernel_size = (u64)(unsigned long)size;
39 os_info.csum = os_info_csum(&os_info);
40 }
41
42 /*
43 * Add OS info entry and update checksum
44 */
os_info_entry_add(int nr,void * ptr,u64 size)45 void os_info_entry_add(int nr, void *ptr, u64 size)
46 {
47 os_info.entry[nr].addr = (u64)(unsigned long)ptr;
48 os_info.entry[nr].size = size;
49 os_info.entry[nr].csum = csum_partial(ptr, size, 0);
50 os_info.csum = os_info_csum(&os_info);
51 }
52
53 /*
54 * Initialize OS info struture and set lowcore pointer
55 */
os_info_init(void)56 void __init os_info_init(void)
57 {
58 void *ptr = &os_info;
59
60 os_info.version_major = OS_INFO_VERSION_MAJOR;
61 os_info.version_minor = OS_INFO_VERSION_MINOR;
62 os_info.magic = OS_INFO_MAGIC;
63 os_info.csum = os_info_csum(&os_info);
64 mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
65 }
66
67 #ifdef CONFIG_CRASH_DUMP
68
69 static struct os_info *os_info_old;
70
71 /*
72 * Allocate and copy OS info entry from oldmem
73 */
os_info_old_alloc(int nr,int align)74 static void os_info_old_alloc(int nr, int align)
75 {
76 unsigned long addr, size = 0;
77 char *buf, *buf_align, *msg;
78 u32 csum;
79
80 addr = os_info_old->entry[nr].addr;
81 if (!addr) {
82 msg = "not available";
83 goto fail;
84 }
85 size = os_info_old->entry[nr].size;
86 buf = kmalloc(size + align - 1, GFP_KERNEL);
87 if (!buf) {
88 msg = "alloc failed";
89 goto fail;
90 }
91 buf_align = PTR_ALIGN(buf, align);
92 if (copy_from_oldmem(buf_align, (void *) addr, size)) {
93 msg = "copy failed";
94 goto fail_free;
95 }
96 csum = csum_partial(buf_align, size, 0);
97 if (csum != os_info_old->entry[nr].csum) {
98 msg = "checksum failed";
99 goto fail_free;
100 }
101 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
102 msg = "copied";
103 goto out;
104 fail_free:
105 kfree(buf);
106 fail:
107 os_info_old->entry[nr].addr = 0;
108 out:
109 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
110 nr, msg, addr, size);
111 }
112
113 /*
114 * Initialize os info and os info entries from oldmem
115 */
os_info_old_init(void)116 static void os_info_old_init(void)
117 {
118 static int os_info_init;
119 unsigned long addr;
120
121 if (os_info_init)
122 return;
123 if (!OLDMEM_BASE)
124 goto fail;
125 if (copy_from_oldmem(&addr, &S390_lowcore.os_info, sizeof(addr)))
126 goto fail;
127 if (addr == 0 || addr % PAGE_SIZE)
128 goto fail;
129 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
130 if (!os_info_old)
131 goto fail;
132 if (copy_from_oldmem(os_info_old, (void *) addr, sizeof(*os_info_old)))
133 goto fail_free;
134 if (os_info_old->magic != OS_INFO_MAGIC)
135 goto fail_free;
136 if (os_info_old->csum != os_info_csum(os_info_old))
137 goto fail_free;
138 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
139 goto fail_free;
140 os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
141 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
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