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/abs_lowcore.h>
17 #include <asm/os_info.h>
18 #include <asm/maccess.h>
19 #include <asm/asm-offsets.h>
20
21 /*
22 * OS info structure has to be page aligned
23 */
24 static struct os_info os_info __page_aligned_data;
25
26 /*
27 * Compute checksum over OS info structure
28 */
os_info_csum(struct os_info * os_info)29 u32 os_info_csum(struct os_info *os_info)
30 {
31 int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
32 return (__force u32)csum_partial(&os_info->version_major, size, 0);
33 }
34
35 /*
36 * Add crashkernel info to OS info and update checksum
37 */
os_info_crashkernel_add(unsigned long base,unsigned long size)38 void os_info_crashkernel_add(unsigned long base, unsigned long size)
39 {
40 os_info.crashkernel_addr = (u64)(unsigned long)base;
41 os_info.crashkernel_size = (u64)(unsigned long)size;
42 os_info.csum = os_info_csum(&os_info);
43 }
44
45 /*
46 * Add OS info entry and update checksum
47 */
os_info_entry_add(int nr,void * ptr,u64 size)48 void os_info_entry_add(int nr, void *ptr, u64 size)
49 {
50 os_info.entry[nr].addr = __pa(ptr);
51 os_info.entry[nr].size = size;
52 os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
53 os_info.csum = os_info_csum(&os_info);
54 }
55
56 /*
57 * Initialize OS info structure and set lowcore pointer
58 */
os_info_init(void)59 void __init os_info_init(void)
60 {
61 struct lowcore *abs_lc;
62 unsigned long flags;
63
64 os_info.version_major = OS_INFO_VERSION_MAJOR;
65 os_info.version_minor = OS_INFO_VERSION_MINOR;
66 os_info.magic = OS_INFO_MAGIC;
67 os_info.csum = os_info_csum(&os_info);
68 abs_lc = get_abs_lowcore(&flags);
69 abs_lc->os_info = __pa(&os_info);
70 put_abs_lowcore(abs_lc, flags);
71 }
72
73 #ifdef CONFIG_CRASH_DUMP
74
75 static struct os_info *os_info_old;
76
77 /*
78 * Allocate and copy OS info entry from oldmem
79 */
os_info_old_alloc(int nr,int align)80 static void os_info_old_alloc(int nr, int align)
81 {
82 unsigned long addr, size = 0;
83 char *buf, *buf_align, *msg;
84 u32 csum;
85
86 addr = os_info_old->entry[nr].addr;
87 if (!addr) {
88 msg = "not available";
89 goto fail;
90 }
91 size = os_info_old->entry[nr].size;
92 buf = kmalloc(size + align - 1, GFP_KERNEL);
93 if (!buf) {
94 msg = "alloc failed";
95 goto fail;
96 }
97 buf_align = PTR_ALIGN(buf, align);
98 if (copy_oldmem_kernel(buf_align, addr, size)) {
99 msg = "copy failed";
100 goto fail_free;
101 }
102 csum = (__force u32)csum_partial(buf_align, size, 0);
103 if (csum != os_info_old->entry[nr].csum) {
104 msg = "checksum failed";
105 goto fail_free;
106 }
107 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
108 msg = "copied";
109 goto out;
110 fail_free:
111 kfree(buf);
112 fail:
113 os_info_old->entry[nr].addr = 0;
114 out:
115 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
116 nr, msg, addr, size);
117 }
118
119 /*
120 * Initialize os info and os info entries from oldmem
121 */
os_info_old_init(void)122 static void os_info_old_init(void)
123 {
124 static int os_info_init;
125 unsigned long addr;
126
127 if (os_info_init)
128 return;
129 if (!oldmem_data.start)
130 goto fail;
131 if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
132 goto fail;
133 if (addr == 0 || addr % PAGE_SIZE)
134 goto fail;
135 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
136 if (!os_info_old)
137 goto fail;
138 if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
139 goto fail_free;
140 if (os_info_old->magic != OS_INFO_MAGIC)
141 goto fail_free;
142 if (os_info_old->csum != os_info_csum(os_info_old))
143 goto fail_free;
144 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
145 goto fail_free;
146 os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
147 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
148 pr_info("crashkernel: addr=0x%lx size=%lu\n",
149 (unsigned long) os_info_old->crashkernel_addr,
150 (unsigned long) os_info_old->crashkernel_size);
151 os_info_init = 1;
152 return;
153 fail_free:
154 kfree(os_info_old);
155 fail:
156 os_info_init = 1;
157 os_info_old = NULL;
158 }
159
160 /*
161 * Return pointer to os infor entry and its size
162 */
os_info_old_entry(int nr,unsigned long * size)163 void *os_info_old_entry(int nr, unsigned long *size)
164 {
165 os_info_old_init();
166
167 if (!os_info_old)
168 return NULL;
169 if (!os_info_old->entry[nr].addr)
170 return NULL;
171 *size = (unsigned long) os_info_old->entry[nr].size;
172 return (void *)(unsigned long)os_info_old->entry[nr].addr;
173 }
174 #endif
175