arch/s390/kernel/os_info.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * OS info memory interface
   4  *
   5  * Copyright IBM Corp. 2012
   6  * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
   7  */
   8
   9 #define KMSG_COMPONENT "os_info"
  10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  11
  12 #include <linux/crash_dump.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <asm/checksum.h>
  16 #include <asm/lowcore.h>
  17 #include <asm/os_info.h>
  18
  19 /*
  20  * OS info structure has to be page aligned
  21  */
  22 static struct os_info os_info __page_aligned_data;
  23
  24 /*
  25  * Compute checksum over OS info structure
  26  */
  27 u32 os_info_csum(struct os_info *os_info)
  28 {
  29         int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
  30         return (__force u32)csum_partial(&os_info->version_major, size, 0);
  31 }
  32
  33 /*
  34  * Add crashkernel info to OS info and update checksum
  35  */
  36 void os_info_crashkernel_add(unsigned long base, unsigned long size)
  37 {
  38         os_info.crashkernel_addr = (u64)(unsigned long)base;
  39         os_info.crashkernel_size = (u64)(unsigned long)size;
  40         os_info.csum = os_info_csum(&os_info);
  41 }
  42
  43 /*
  44  * Add OS info entry and update checksum
  45  */
  46 void os_info_entry_add(int nr, void *ptr, u64 size)
  47 {
  48         os_info.entry[nr].addr = (u64)(unsigned long)ptr;
  49         os_info.entry[nr].size = size;
  50         os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
  51         os_info.csum = os_info_csum(&os_info);
  52 }
  53
  54 /*
  55  * Initialize OS info struture and set lowcore pointer
  56  */
  57 void __init os_info_init(void)
  58 {
  59         void *ptr = &os_info;
  60
  61         os_info.version_major = OS_INFO_VERSION_MAJOR;
  62         os_info.version_minor = OS_INFO_VERSION_MINOR;
  63         os_info.magic = OS_INFO_MAGIC;
  64         os_info.csum = os_info_csum(&os_info);
  65         mem_assign_absolute(S390_lowcore.os_info, (unsigned long) ptr);
  66 }
  67
  68 #ifdef CONFIG_CRASH_DUMP
  69
  70 static struct os_info *os_info_old;
  71
  72 /*
  73  * Allocate and copy OS info entry from oldmem
  74  */
  75 static void os_info_old_alloc(int nr, int align)
  76 {
  77         unsigned long addr, size = 0;
  78         char *buf, *buf_align, *msg;
  79         u32 csum;
  80
  81         addr = os_info_old->entry[nr].addr;
  82         if (!addr) {
  83                 msg = "not available";
  84                 goto fail;
  85         }
  86         size = os_info_old->entry[nr].size;
  87         buf = kmalloc(size + align - 1, GFP_KERNEL);
  88         if (!buf) {
  89                 msg = "alloc failed";
  90                 goto fail;
  91         }
  92         buf_align = PTR_ALIGN(buf, align);
  93         if (copy_oldmem_kernel(buf_align, (void *) addr, size)) {
  94                 msg = "copy failed";
  95                 goto fail_free;
  96         }
  97         csum = (__force u32)csum_partial(buf_align, size, 0);
  98         if (csum != os_info_old->entry[nr].csum) {
  99                 msg = "checksum failed";
 100                 goto fail_free;
 101         }
 102         os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
 103         msg = "copied";
 104         goto out;
 105 fail_free:
 106         kfree(buf);
 107 fail:
 108         os_info_old->entry[nr].addr = 0;
 109 out:
 110         pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
 111                 nr, msg, addr, size);
 112 }
 113
 114 /*
 115  * Initialize os info and os info entries from oldmem
 116  */
 117 static void os_info_old_init(void)
 118 {
 119         static int os_info_init;
 120         unsigned long addr;
 121
 122         if (os_info_init)
 123                 return;
 124         if (!OLDMEM_BASE)
 125                 goto fail;
 126         if (copy_oldmem_kernel(&addr, &S390_lowcore.os_info, sizeof(addr)))
 127                 goto fail;
 128         if (addr == 0 || addr % PAGE_SIZE)
 129                 goto fail;
 130         os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
 131         if (!os_info_old)
 132                 goto fail;
 133         if (copy_oldmem_kernel(os_info_old, (void *) addr,
 134                                sizeof(*os_info_old)))
 135                 goto fail_free;
 136         if (os_info_old->magic != OS_INFO_MAGIC)
 137                 goto fail_free;
 138         if (os_info_old->csum != os_info_csum(os_info_old))
 139                 goto fail_free;
 140         if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
 141                 goto fail_free;
 142         os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
 143         os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
 144         pr_info("crashkernel: addr=0x%lx size=%lu\n",
 145                 (unsigned long) os_info_old->crashkernel_addr,
 146                 (unsigned long) os_info_old->crashkernel_size);
 147         os_info_init = 1;
 148         return;
 149 fail_free:
 150         kfree(os_info_old);
 151 fail:
 152         os_info_init = 1;
 153         os_info_old = NULL;
 154 }
 155
 156 /*
 157  * Return pointer to os infor entry and its size
 158  */
 159 void *os_info_old_entry(int nr, unsigned long *size)
 160 {
 161         os_info_old_init();
 162
 163         if (!os_info_old)
 164                 return NULL;
 165         if (!os_info_old->entry[nr].addr)
 166                 return NULL;
 167         *size = (unsigned long) os_info_old->entry[nr].size;
 168         return (void *)(unsigned long)os_info_old->entry[nr].addr;
 169 }
 170 #endif