arch/s390/kernel/os_info.c

   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  */
  21 static struct os_info os_info __page_aligned_data;
  22
  23 /*
  24  * Compute checksum over OS info structure
  25  */
  26 u32 os_info_csum(struct os_info *os_info)
  27 {
  28         int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
  29         return (__force u32)csum_partial(&os_info->version_major, size, 0);
  30 }
  31
  32 /*
  33  * Add crashkernel info to OS info and update checksum
  34  */
  35 void 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  */
  45 void 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 = (__force u32)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  */
  56 void __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
  69 static struct os_info *os_info_old;
  70
  71 /*
  72  * Allocate and copy OS info entry from oldmem
  73  */
  74 static 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 = (__force u32)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;
 104 fail_free:
 105         kfree(buf);
 106 fail:
 107         os_info_old->entry[nr].addr = 0;
 108 out:
 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  */
 116 static 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;
 148 fail_free:
 149         kfree(os_info_old);
 150 fail:
 151         os_info_init = 1;
 152         os_info_old = NULL;
 153 }
 154
 155 /*
 156  * Return pointer to os infor entry and its size
 157  */
 158 void *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