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/physmem_info.h>
19 #include <asm/maccess.h>
20 #include <asm/asm-offsets.h>
21 #include <asm/ipl.h>
22
23 /*
24 * OS info structure has to be page aligned
25 */
26 static struct os_info os_info __page_aligned_data;
27
28 /*
29 * Compute checksum over OS info structure
30 */
os_info_csum(struct os_info * os_info)31 u32 os_info_csum(struct os_info *os_info)
32 {
33 int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
34 return (__force u32)cksm(&os_info->version_major, size, 0);
35 }
36
37 /*
38 * Add crashkernel info to OS info and update checksum
39 */
os_info_crashkernel_add(unsigned long base,unsigned long size)40 void os_info_crashkernel_add(unsigned long base, unsigned long size)
41 {
42 os_info.crashkernel_addr = (u64)(unsigned long)base;
43 os_info.crashkernel_size = (u64)(unsigned long)size;
44 os_info.csum = os_info_csum(&os_info);
45 }
46
47 /*
48 * Add OS info data entry and update checksum
49 */
os_info_entry_add_data(int nr,void * ptr,u64 size)50 void os_info_entry_add_data(int nr, void *ptr, u64 size)
51 {
52 os_info.entry[nr].addr = __pa(ptr);
53 os_info.entry[nr].size = size;
54 os_info.entry[nr].csum = (__force u32)cksm(ptr, size, 0);
55 os_info.csum = os_info_csum(&os_info);
56 }
57
58 /*
59 * Add OS info value entry and update checksum
60 */
os_info_entry_add_val(int nr,u64 value)61 void os_info_entry_add_val(int nr, u64 value)
62 {
63 os_info.entry[nr].val = value;
64 os_info.entry[nr].size = 0;
65 os_info.entry[nr].csum = 0;
66 os_info.csum = os_info_csum(&os_info);
67 }
68
69 /*
70 * Initialize OS info structure and set lowcore pointer
71 */
os_info_init(void)72 void __init os_info_init(void)
73 {
74 struct lowcore *abs_lc;
75
76 BUILD_BUG_ON(sizeof(struct os_info) != PAGE_SIZE);
77 os_info.version_major = OS_INFO_VERSION_MAJOR;
78 os_info.version_minor = OS_INFO_VERSION_MINOR;
79 os_info.magic = OS_INFO_MAGIC;
80 os_info_entry_add_val(OS_INFO_IDENTITY_BASE, __identity_base);
81 os_info_entry_add_val(OS_INFO_KASLR_OFFSET, kaslr_offset());
82 os_info_entry_add_val(OS_INFO_KASLR_OFF_PHYS, __kaslr_offset_phys);
83 os_info_entry_add_val(OS_INFO_VMEMMAP, (unsigned long)vmemmap);
84 os_info_entry_add_val(OS_INFO_AMODE31_START, AMODE31_START);
85 os_info_entry_add_val(OS_INFO_AMODE31_END, AMODE31_END);
86 os_info_entry_add_val(OS_INFO_IMAGE_START, (unsigned long)_stext);
87 os_info_entry_add_val(OS_INFO_IMAGE_END, (unsigned long)_end);
88 os_info_entry_add_val(OS_INFO_IMAGE_PHYS, __pa_symbol(_stext));
89 os_info.csum = os_info_csum(&os_info);
90 abs_lc = get_abs_lowcore();
91 abs_lc->os_info = __pa(&os_info);
92 put_abs_lowcore(abs_lc);
93 }
94
95 #ifdef CONFIG_CRASH_DUMP
96
97 static struct os_info *os_info_old;
98
99 /*
100 * Allocate and copy OS info entry from oldmem
101 */
os_info_old_alloc(int nr,int align)102 static void os_info_old_alloc(int nr, int align)
103 {
104 unsigned long addr, size = 0;
105 char *buf, *buf_align, *msg;
106 u32 csum;
107
108 addr = os_info_old->entry[nr].addr;
109 if (!addr) {
110 msg = "not available";
111 goto fail;
112 }
113 size = os_info_old->entry[nr].size;
114 buf = kmalloc(size + align - 1, GFP_KERNEL);
115 if (!buf) {
116 msg = "alloc failed";
117 goto fail;
118 }
119 buf_align = PTR_ALIGN(buf, align);
120 if (copy_oldmem_kernel(buf_align, addr, size)) {
121 msg = "copy failed";
122 goto fail_free;
123 }
124 csum = (__force u32)cksm(buf_align, size, 0);
125 if (csum != os_info_old->entry[nr].csum) {
126 msg = "checksum failed";
127 goto fail_free;
128 }
129 os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
130 msg = "copied";
131 goto out;
132 fail_free:
133 kfree(buf);
134 fail:
135 os_info_old->entry[nr].addr = 0;
136 out:
137 pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
138 nr, msg, addr, size);
139 }
140
141 /*
142 * Initialize os info and os info entries from oldmem
143 */
os_info_old_init(void)144 static void os_info_old_init(void)
145 {
146 static int os_info_init;
147 unsigned long addr;
148
149 if (os_info_init)
150 return;
151 if (!oldmem_data.start && !is_ipl_type_dump())
152 goto fail;
153 if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
154 goto fail;
155 if (addr == 0 || addr % PAGE_SIZE)
156 goto fail;
157 os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
158 if (!os_info_old)
159 goto fail;
160 if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
161 goto fail_free;
162 if (os_info_old->magic != OS_INFO_MAGIC)
163 goto fail_free;
164 if (os_info_old->csum != os_info_csum(os_info_old))
165 goto fail_free;
166 if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
167 goto fail_free;
168 os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
169 os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
170 pr_info("crashkernel: addr=0x%lx size=%lu\n",
171 (unsigned long) os_info_old->crashkernel_addr,
172 (unsigned long) os_info_old->crashkernel_size);
173 os_info_init = 1;
174 return;
175 fail_free:
176 kfree(os_info_old);
177 fail:
178 os_info_init = 1;
179 os_info_old = NULL;
180 }
181
182 /*
183 * Return pointer to os infor entry and its size
184 */
os_info_old_entry(int nr,unsigned long * size)185 void *os_info_old_entry(int nr, unsigned long *size)
186 {
187 os_info_old_init();
188
189 if (!os_info_old)
190 return NULL;
191 if (!os_info_old->entry[nr].addr)
192 return NULL;
193 *size = (unsigned long) os_info_old->entry[nr].size;
194 return (void *)(unsigned long)os_info_old->entry[nr].addr;
195 }
196 #endif
197