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 #include <asm/asm-offsets.h>
19
20 /*
21 * OS info structure has to be page aligned
22 */
23 static struct os_info os_info __page_aligned_data;
24
25 /*
26 * Compute checksum over OS info structure
27 */
os_info_csum(struct os_info * os_info)28 u32 os_info_csum(struct os_info *os_info)
29 {
30 int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
31 return (__force u32)csum_partial(&os_info->version_major, size, 0);
32 }
33
34 /*
35 * Add crashkernel info to OS info and update checksum
36 */
os_info_crashkernel_add(unsigned long base,unsigned long size)37 void os_info_crashkernel_add(unsigned long base, unsigned long size)
38 {
39 os_info.crashkernel_addr = (u64)(unsigned long)base;
40 os_info.crashkernel_size = (u64)(unsigned long)size;
41 os_info.csum = os_info_csum(&os_info);
42 }
43
44 /*
45 * Add OS info entry and update checksum
46 */
os_info_entry_add(int nr,void * ptr,u64 size)47 void os_info_entry_add(int nr, void *ptr, u64 size)
48 {
49 os_info.entry[nr].addr = (u64)(unsigned long)ptr;
50 os_info.entry[nr].size = size;
51 os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
52 os_info.csum = os_info_csum(&os_info);
53 }
54
55 /*
56 * Initialize OS info struture and set lowcore pointer
57 */
os_info_init(void)58 void __init os_info_init(void)
59 {
60 void *ptr = &os_info;
61
62 os_info.version_major = OS_INFO_VERSION_MAJOR;
63 os_info.version_minor = OS_INFO_VERSION_MINOR;
64 os_info.magic = OS_INFO_MAGIC;
65 os_info.csum = os_info_csum(&os_info);
66 mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
67 }
68
69 #ifdef CONFIG_CRASH_DUMP
70
71 static struct os_info *os_info_old;
72
73 /*
74 * Allocate and copy OS info entry from oldmem
75 */
os_info_old_alloc(int nr,int align)76 static void os_info_old_alloc(int nr, int align)
77 {
78 unsigned long addr, size = 0;
79 char *buf, *buf_align, *msg;
80 u32 csum;
81
82 addr = os_info_old->entry[nr].addr;
83 if (!addr) {
84 msg = "not available";
85 goto fail;
86 }
87 size = os_info_old->entry[nr].size;
88 buf = kmalloc(size + align - 1, GFP_KERNEL);
89 if (!buf) {
90 msg = "alloc failed";
91 goto fail;
92 }
93 buf_align = PTR_ALIGN(buf, align);
94 if (copy_oldmem_kernel(buf_align, (void *) addr, size)) {
95 msg = "copy failed";
96 goto fail_free;
97 }
98 csum = (__force u32)csum_partial(buf_align, size, 0);
99 if (csum != os_info_old->entry[nr].csum) {
100 msg = "checksum failed";
101 goto fail_free;
102 }
103 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
104 msg = "copied";
105 goto out;
106 fail_free:
107 kfree(buf);
108 fail:
109 os_info_old->entry[nr].addr = 0;
110 out:
111 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
112 nr, msg, addr, size);
113 }
114
115 /*
116 * Initialize os info and os info entries from oldmem
117 */
os_info_old_init(void)118 static void os_info_old_init(void)
119 {
120 static int os_info_init;
121 unsigned long addr;
122
123 if (os_info_init)
124 return;
125 if (!OLDMEM_BASE)
126 goto fail;
127 if (copy_oldmem_kernel(&addr, (void *)__LC_OS_INFO, sizeof(addr)))
128 goto fail;
129 if (addr == 0 || addr % PAGE_SIZE)
130 goto fail;
131 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
132 if (!os_info_old)
133 goto fail;
134 if (copy_oldmem_kernel(os_info_old, (void *) addr,
135 sizeof(*os_info_old)))
136 goto fail_free;
137 if (os_info_old->magic != OS_INFO_MAGIC)
138 goto fail_free;
139 if (os_info_old->csum != os_info_csum(os_info_old))
140 goto fail_free;
141 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
142 goto fail_free;
143 os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
144 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
145 pr_info("crashkernel: addr=0x%lx size=%lu\n",
146 (unsigned long) os_info_old->crashkernel_addr,
147 (unsigned long) os_info_old->crashkernel_size);
148 os_info_init = 1;
149 return;
150 fail_free:
151 kfree(os_info_old);
152 fail:
153 os_info_init = 1;
154 os_info_old = NULL;
155 }
156
157 /*
158 * Return pointer to os infor entry and its size
159 */
os_info_old_entry(int nr,unsigned long * size)160 void *os_info_old_entry(int nr, unsigned long *size)
161 {
162 os_info_old_init();
163
164 if (!os_info_old)
165 return NULL;
166 if (!os_info_old->entry[nr].addr)
167 return NULL;
168 *size = (unsigned long) os_info_old->entry[nr].size;
169 return (void *)(unsigned long)os_info_old->entry[nr].addr;
170 }
171 #endif
172