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_oldmem_kernel(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_oldmem_kernel(&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_oldmem_kernel(os_info_old, (void *) addr,
133			       sizeof(*os_info_old)))
134		goto fail_free;
135	if (os_info_old->magic != OS_INFO_MAGIC)
136		goto fail_free;
137	if (os_info_old->csum != os_info_csum(os_info_old))
138		goto fail_free;
139	if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
140		goto fail_free;
141	os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
142	os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
143	pr_info("crashkernel: addr=0x%lx size=%lu\n",
144		(unsigned long) os_info_old->crashkernel_addr,
145		(unsigned long) os_info_old->crashkernel_size);
146	os_info_init = 1;
147	return;
148fail_free:
149	kfree(os_info_old);
150fail:
151	os_info_init = 1;
152	os_info_old = NULL;
153}
154
155/*
156 * Return pointer to os infor entry and its size
157 */
158void *os_info_old_entry(int nr, unsigned long *size)
159{
160	os_info_old_init();
161
162	if (!os_info_old)
163		return NULL;
164	if (!os_info_old->entry[nr].addr)
165		return NULL;
166	*size = (unsigned long) os_info_old->entry[nr].size;
167	return (void *)(unsigned long)os_info_old->entry[nr].addr;
168}
169#endif