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 <[email protected]>
   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 #include <asm/asm-offsets.h>
  19
  20 /*
  21  * OS info structure has to be page aligned
  22  */
  23 static struct os_info os_info __page_aligned_data;
  24
  25 /*
  26  * Compute checksum over OS info structure
  27  */
  28 u32 os_info_csum(struct os_info *os_info)
  29 {
  30         int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
  31         return (__force u32)csum_partial(&os_info->version_major, size, 0);
  32 }
  33
  34 /*
  35  * Add crashkernel info to OS info and update checksum
  36  */
  37 void os_info_crashkernel_add(unsigned long base, unsigned long size)
  38 {
  39         os_info.crashkernel_addr = (u64)(unsigned long)base;
  40         os_info.crashkernel_size = (u64)(unsigned long)size;
  41         os_info.csum = os_info_csum(&os_info);
  42 }
  43
  44 /*
  45  * Add OS info entry and update checksum
  46  */
  47 void os_info_entry_add(int nr, void *ptr, u64 size)
  48 {
  49         os_info.entry[nr].addr = __pa(ptr);
  50         os_info.entry[nr].size = size;
  51         os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
  52         os_info.csum = os_info_csum(&os_info);
  53 }
  54
  55 /*
  56  * Initialize OS info structure and set lowcore pointer
  57  */
  58 void __init os_info_init(void)
  59 {
  60         void *ptr = &os_info;
  61
  62         os_info.version_major = OS_INFO_VERSION_MAJOR;
  63         os_info.version_minor = OS_INFO_VERSION_MINOR;
  64         os_info.magic = OS_INFO_MAGIC;
  65         os_info.csum = os_info_csum(&os_info);
  66         put_abs_lowcore(os_info, __pa(ptr));
  67 }
  68
  69 #ifdef CONFIG_CRASH_DUMP
  70
  71 static struct os_info *os_info_old;
  72
  73 /*
  74  * Allocate and copy OS info entry from oldmem
  75  */
  76 static void os_info_old_alloc(int nr, int align)
  77 {
  78         unsigned long addr, size = 0;
  79         char *buf, *buf_align, *msg;
  80         u32 csum;
  81
  82         addr = os_info_old->entry[nr].addr;
  83         if (!addr) {
  84                 msg = "not available";
  85                 goto fail;
  86         }
  87         size = os_info_old->entry[nr].size;
  88         buf = kmalloc(size + align - 1, GFP_KERNEL);
  89         if (!buf) {
  90                 msg = "alloc failed";
  91                 goto fail;
  92         }
  93         buf_align = PTR_ALIGN(buf, align);
  94         if (copy_oldmem_kernel(buf_align, addr, size)) {
  95                 msg = "copy failed";
  96                 goto fail_free;
  97         }
  98         csum = (__force u32)csum_partial(buf_align, size, 0);
  99         if (csum != os_info_old->entry[nr].csum) {
 100                 msg = "checksum failed";
 101                 goto fail_free;
 102         }
 103         os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
 104         msg = "copied";
 105         goto out;
 106 fail_free:
 107         kfree(buf);
 108 fail:
 109         os_info_old->entry[nr].addr = 0;
 110 out:
 111         pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
 112                 nr, msg, addr, size);
 113 }
 114
 115 /*
 116  * Initialize os info and os info entries from oldmem
 117  */
 118 static void os_info_old_init(void)
 119 {
 120         static int os_info_init;
 121         unsigned long addr;
 122
 123         if (os_info_init)
 124                 return;
 125         if (!oldmem_data.start)
 126                 goto fail;
 127         if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
 128                 goto fail;
 129         if (addr == 0 || addr % PAGE_SIZE)
 130                 goto fail;
 131         os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
 132         if (!os_info_old)
 133                 goto fail;
 134         if (copy_oldmem_kernel(os_info_old, addr, 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