1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * OS info memory interface
4 *
5 * Copyright IBM Corp. 2012
6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
7 */
8
9 #define KMSG_COMPONENT "os_info"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12 #include <linux/crash_dump.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <asm/checksum.h>
16 #include <asm/lowcore.h>
17 #include <asm/os_info.h>
18
19 /*
20 * OS info structure has to be page aligned
21 */
22 static struct os_info os_info __page_aligned_data;
23
24 /*
25 * Compute checksum over OS info structure
26 */
os_info_csum(struct os_info * os_info)27 u32 os_info_csum(struct os_info *os_info)
28 {
29 int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
30 return (__force u32)csum_partial(&os_info->version_major, size, 0);
31 }
32
33 /*
34 * Add crashkernel info to OS info and update checksum
35 */
os_info_crashkernel_add(unsigned long base,unsigned long size)36 void os_info_crashkernel_add(unsigned long base, unsigned long size)
37 {
38 os_info.crashkernel_addr = (u64)(unsigned long)base;
39 os_info.crashkernel_size = (u64)(unsigned long)size;
40 os_info.csum = os_info_csum(&os_info);
41 }
42
43 /*
44 * Add OS info entry and update checksum
45 */
os_info_entry_add(int nr,void * ptr,u64 size)46 void os_info_entry_add(int nr, void *ptr, u64 size)
47 {
48 os_info.entry[nr].addr = (u64)(unsigned long)ptr;
49 os_info.entry[nr].size = size;
50 os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
51 os_info.csum = os_info_csum(&os_info);
52 }
53
54 /*
55 * Initialize OS info structure and set lowcore pointer
56 */
os_info_init(void)57 void __init os_info_init(void)
58 {
59 void *ptr = &os_info;
60
61 os_info.version_major = OS_INFO_VERSION_MAJOR;
62 os_info.version_minor = OS_INFO_VERSION_MINOR;
63 os_info.magic = OS_INFO_MAGIC;
64 os_info.csum = os_info_csum(&os_info);
65 mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
66 }
67
68 #ifdef CONFIG_CRASH_DUMP
69
70 static struct os_info *os_info_old;
71
72 /*
73 * Allocate and copy OS info entry from oldmem
74 */
os_info_old_alloc(int nr,int align)75 static void os_info_old_alloc(int nr, int align)
76 {
77 unsigned long addr, size = 0;
78 char *buf, *buf_align, *msg;
79 u32 csum;
80
81 addr = os_info_old->entry[nr].addr;
82 if (!addr) {
83 msg = "not available";
84 goto fail;
85 }
86 size = os_info_old->entry[nr].size;
87 buf = kmalloc(size + align - 1, GFP_KERNEL);
88 if (!buf) {
89 msg = "alloc failed";
90 goto fail;
91 }
92 buf_align = PTR_ALIGN(buf, align);
93 if (copy_oldmem_kernel(buf_align, (void *) addr, size)) {
94 msg = "copy failed";
95 goto fail_free;
96 }
97 csum = (__force u32)csum_partial(buf_align, size, 0);
98 if (csum != os_info_old->entry[nr].csum) {
99 msg = "checksum failed";
100 goto fail_free;
101 }
102 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
103 msg = "copied";
104 goto out;
105 fail_free:
106 kfree(buf);
107 fail:
108 os_info_old->entry[nr].addr = 0;
109 out:
110 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
111 nr, msg, addr, size);
112 }
113
114 /*
115 * Initialize os info and os info entries from oldmem
116 */
os_info_old_init(void)117 static void os_info_old_init(void)
118 {
119 static int os_info_init;
120 unsigned long addr;
121
122 if (os_info_init)
123 return;
124 if (!oldmem_data.start)
125 goto fail;
126 if (copy_oldmem_kernel(&addr, &S390_lowcore.os_info, sizeof(addr)))
127 goto fail;
128 if (addr == 0 || addr % PAGE_SIZE)
129 goto fail;
130 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
131 if (!os_info_old)
132 goto fail;
133 if (copy_oldmem_kernel(os_info_old, (void *) addr,
134 sizeof(*os_info_old)))
135 goto fail_free;
136 if (os_info_old->magic != OS_INFO_MAGIC)
137 goto fail_free;
138 if (os_info_old->csum != os_info_csum(os_info_old))
139 goto fail_free;
140 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
141 goto fail_free;
142 os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
143 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
144 pr_info("crashkernel: addr=0x%lx size=%lu\n",
145 (unsigned long) os_info_old->crashkernel_addr,
146 (unsigned long) os_info_old->crashkernel_size);
147 os_info_init = 1;
148 return;
149 fail_free:
150 kfree(os_info_old);
151 fail:
152 os_info_init = 1;
153 os_info_old = NULL;
154 }
155
156 /*
157 * Return pointer to os infor entry and its size
158 */
os_info_old_entry(int nr,unsigned long * size)159 void *os_info_old_entry(int nr, unsigned long *size)
160 {
161 os_info_old_init();
162
163 if (!os_info_old)
164 return NULL;
165 if (!os_info_old->entry[nr].addr)
166 return NULL;
167 *size = (unsigned long) os_info_old->entry[nr].size;
168 return (void *)(unsigned long)os_info_old->entry[nr].addr;
169 }
170 #endif
171