LXR linux/arch/s390/kernel/os

   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 */
  22static struct os_info os_info __page_aligned_data;
  23
  24/*
  25 * Compute checksum over OS info structure
  26 */
  27u32 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 */
  36void 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 */
  46void 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 */
  57void __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
  70static struct os_info *os_info_old;
  71
  72/*
  73 * Allocate and copy OS info entry from oldmem
  74 */
  75static 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;
 105fail_free:
 106        kfree(buf);
 107fail:
 108        os_info_old->entry[nr].addr = 0;
 109out:
 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 */
 117static 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;
 149fail_free:
 150        kfree(os_info_old);
 151fail:
 152        os_info_init = 1;
 153        os_info_old = NULL;
 154}
 155
 156/*
 157 * Return pointer to os infor entry and its size
 158 */
 159void *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
 171