LXR linux/arch/s390/kernel/os

   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
 170