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/abs_lowcore.h>
  17 #include <asm/os_info.h>
  18 #include <asm/maccess.h>
  19 #include <asm/asm-offsets.h>
  20
  21 /*
  22  * OS info structure has to be page aligned
  23  */
  24 static struct os_info os_info __page_aligned_data;
  25
  26 /*
  27  * Compute checksum over OS info structure
  28  */
  29 u32 os_info_csum(struct os_info *os_info)
  30 {
  31         int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
  32         return (__force u32)csum_partial(&os_info->version_major, size, 0);
  33 }
  34
  35 /*
  36  * Add crashkernel info to OS info and update checksum
  37  */
  38 void os_info_crashkernel_add(unsigned long base, unsigned long size)
  39 {
  40         os_info.crashkernel_addr = (u64)(unsigned long)base;
  41         os_info.crashkernel_size = (u64)(unsigned long)size;
  42         os_info.csum = os_info_csum(&os_info);
  43 }
  44
  45 /*
  46  * Add OS info entry and update checksum
  47  */
  48 void os_info_entry_add(int nr, void *ptr, u64 size)
  49 {
  50         os_info.entry[nr].addr = __pa(ptr);
  51         os_info.entry[nr].size = size;
  52         os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);
  53         os_info.csum = os_info_csum(&os_info);
  54 }
  55
  56 /*
  57  * Initialize OS info structure and set lowcore pointer
  58  */
  59 void __init os_info_init(void)
  60 {
  61         struct lowcore *abs_lc;
  62
  63         os_info.version_major = OS_INFO_VERSION_MAJOR;
  64         os_info.version_minor = OS_INFO_VERSION_MINOR;
  65         os_info.magic = OS_INFO_MAGIC;
  66         os_info.csum = os_info_csum(&os_info);
  67         abs_lc = get_abs_lowcore();
  68         abs_lc->os_info = __pa(&os_info);
  69         put_abs_lowcore(abs_lc);
  70 }
  71
  72 #ifdef CONFIG_CRASH_DUMP
  73
  74 static struct os_info *os_info_old;
  75
  76 /*
  77  * Allocate and copy OS info entry from oldmem
  78  */
  79 static void os_info_old_alloc(int nr, int align)
  80 {
  81         unsigned long addr, size = 0;
  82         char *buf, *buf_align, *msg;
  83         u32 csum;
  84
  85         addr = os_info_old->entry[nr].addr;
  86         if (!addr) {
  87                 msg = "not available";
  88                 goto fail;
  89         }
  90         size = os_info_old->entry[nr].size;
  91         buf = kmalloc(size + align - 1, GFP_KERNEL);
  92         if (!buf) {
  93                 msg = "alloc failed";
  94                 goto fail;
  95         }
  96         buf_align = PTR_ALIGN(buf, align);
  97         if (copy_oldmem_kernel(buf_align, addr, size)) {
  98                 msg = "copy failed";
  99                 goto fail_free;
 100         }
 101         csum = (__force u32)csum_partial(buf_align, size, 0);
 102         if (csum != os_info_old->entry[nr].csum) {
 103                 msg = "checksum failed";
 104                 goto fail_free;
 105         }
 106         os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
 107         msg = "copied";
 108         goto out;
 109 fail_free:
 110         kfree(buf);
 111 fail:
 112         os_info_old->entry[nr].addr = 0;
 113 out:
 114         pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
 115                 nr, msg, addr, size);
 116 }
 117
 118 /*
 119  * Initialize os info and os info entries from oldmem
 120  */
 121 static void os_info_old_init(void)
 122 {
 123         static int os_info_init;
 124         unsigned long addr;
 125
 126         if (os_info_init)
 127                 return;
 128         if (!oldmem_data.start)
 129                 goto fail;
 130         if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
 131                 goto fail;
 132         if (addr == 0 || addr % PAGE_SIZE)
 133                 goto fail;
 134         os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
 135         if (!os_info_old)
 136                 goto fail;
 137         if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
 138                 goto fail_free;
 139         if (os_info_old->magic != OS_INFO_MAGIC)
 140                 goto fail_free;
 141         if (os_info_old->csum != os_info_csum(os_info_old))
 142                 goto fail_free;
 143         if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
 144                 goto fail_free;
 145         os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
 146         os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
 147         pr_info("crashkernel: addr=0x%lx size=%lu\n",
 148                 (unsigned long) os_info_old->crashkernel_addr,
 149                 (unsigned long) os_info_old->crashkernel_size);
 150         os_info_init = 1;
 151         return;
 152 fail_free:
 153         kfree(os_info_old);
 154 fail:
 155         os_info_init = 1;
 156         os_info_old = NULL;
 157 }
 158
 159 /*
 160  * Return pointer to os infor entry and its size
 161  */
 162 void *os_info_old_entry(int nr, unsigned long *size)
 163 {
 164         os_info_old_init();
 165
 166         if (!os_info_old)
 167                 return NULL;
 168         if (!os_info_old->entry[nr].addr)
 169                 return NULL;
 170         *size = (unsigned long) os_info_old->entry[nr].size;
 171         return (void *)(unsigned long)os_info_old->entry[nr].addr;
 172 }
 173 #endif