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 <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  */
  20 static struct os_info os_info __page_aligned_data;
  21
  22 /*
  23  * Compute checksum over OS info structure
  24  */
  25 u32 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  */
  34 void 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  */
  44 void 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  */
  55 void __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         mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
  64 }
  65
  66 #ifdef CONFIG_CRASH_DUMP
  67
  68 static struct os_info *os_info_old;
  69
  70 /*
  71  * Allocate and copy OS info entry from oldmem
  72  */
  73 static 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;
 103 fail_free:
 104         kfree(buf);
 105 fail:
 106         os_info_old->entry[nr].addr = 0;
 107 out:
 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  */
 115 static 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         pr_info("crashkernel: addr=0x%lx size=%lu\n",
 142                 (unsigned long) os_info_old->crashkernel_addr,
 143                 (unsigned long) os_info_old->crashkernel_size);
 144         os_info_init = 1;
 145         return;
 146 fail_free:
 147         kfree(os_info_old);
 148 fail:
 149         os_info_init = 1;
 150         os_info_old = NULL;
 151 }
 152
 153 /*
 154  * Return pointer to os infor entry and its size
 155  */
 156 void *os_info_old_entry(int nr, unsigned long *size)
 157 {
 158         os_info_old_init();
 159
 160         if (!os_info_old)
 161                 return NULL;
 162         if (!os_info_old->entry[nr].addr)
 163                 return NULL;
 164         *size = (unsigned long) os_info_old->entry[nr].size;
 165         return (void *)(unsigned long)os_info_old->entry[nr].addr;
 166 }
 167 #endif