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 <asm/checksum.h>
14#include <asm/lowcore.h>
15#include <asm/os_info.h>
16
17/*
18 * OS info structure has to be page aligned
19 */
20static struct os_info os_info __page_aligned_data;
21
22/*
23 * Compute checksum over OS info structure
24 */
25u32 os_info_csum(struct os_info *os_info)
26{
27	int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
28	return csum_partial(&os_info->version_major, size, 0);
29}
30
31/*
32 * Add crashkernel info to OS info and update checksum
33 */
34void os_info_crashkernel_add(unsigned long base, unsigned long size)
35{
36	os_info.crashkernel_addr = (u64)(unsigned long)base;
37	os_info.crashkernel_size = (u64)(unsigned long)size;
38	os_info.csum = os_info_csum(&os_info);
39}
40
41/*
42 * Add OS info entry and update checksum
43 */
44void os_info_entry_add(int nr, void *ptr, u64 size)
45{
46	os_info.entry[nr].addr = (u64)(unsigned long)ptr;
47	os_info.entry[nr].size = size;
48	os_info.entry[nr].csum = csum_partial(ptr, size, 0);
49	os_info.csum = os_info_csum(&os_info);
50}
51
52/*
53 * Initialize OS info struture and set lowcore pointer
54 */
55void __init os_info_init(void)
56{
57	void *ptr = &os_info;
58
59	os_info.version_major = OS_INFO_VERSION_MAJOR;
60	os_info.version_minor = OS_INFO_VERSION_MINOR;
61	os_info.magic = OS_INFO_MAGIC;
62	os_info.csum = os_info_csum(&os_info);
63	copy_to_absolute_zero(&S390_lowcore.os_info, &ptr, sizeof(ptr));
64}
65
66#ifdef CONFIG_CRASH_DUMP
67
68static struct os_info *os_info_old;
69
70/*
71 * Allocate and copy OS info entry from oldmem
72 */
73static void os_info_old_alloc(int nr, int align)
74{
75	unsigned long addr, size = 0;
76	char *buf, *buf_align, *msg;
77	u32 csum;
78
79	addr = os_info_old->entry[nr].addr;
80	if (!addr) {
81		msg = "not available";
82		goto fail;
83	}
84	size = os_info_old->entry[nr].size;
85	buf = kmalloc(size + align - 1, GFP_KERNEL);
86	if (!buf) {
87		msg = "alloc failed";
88		goto fail;
89	}
90	buf_align = PTR_ALIGN(buf, align);
91	if (copy_from_oldmem(buf_align, (void *) addr, size)) {
92		msg = "copy failed";
93		goto fail_free;
94	}
95	csum = csum_partial(buf_align, size, 0);
96	if (csum != os_info_old->entry[nr].csum) {
97		msg = "checksum failed";
98		goto fail_free;
99	}
100	os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
101	msg = "copied";
102	goto out;
103fail_free:
104	kfree(buf);
105fail:
106	os_info_old->entry[nr].addr = 0;
107out:
108	pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
109		nr, msg, addr, size);
110}
111
112/*
113 * Initialize os info and os info entries from oldmem
114 */
115static void os_info_old_init(void)
116{
117	static int os_info_init;
118	unsigned long addr;
119
120	if (os_info_init)
121		return;
122	if (!OLDMEM_BASE)
123		goto fail;
124	if (copy_from_oldmem(&addr, &S390_lowcore.os_info, sizeof(addr)))
125		goto fail;
126	if (addr == 0 || addr % PAGE_SIZE)
127		goto fail;
128	os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
129	if (!os_info_old)
130		goto fail;
131	if (copy_from_oldmem(os_info_old, (void *) addr, sizeof(*os_info_old)))
132		goto fail_free;
133	if (os_info_old->magic != OS_INFO_MAGIC)
134		goto fail_free;
135	if (os_info_old->csum != os_info_csum(os_info_old))
136		goto fail_free;
137	if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
138		goto fail_free;
139	os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
140	os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
141	os_info_old_alloc(OS_INFO_INIT_FN, PAGE_SIZE);
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;
147fail_free:
148	kfree(os_info_old);
149fail:
150	os_info_init = 1;
151	os_info_old = NULL;
152}
153
154/*
155 * Return pointer to os infor entry and its size
156 */
157void *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