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