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/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         unsigned long flags;
  63
  64         os_info.version_major = OS_INFO_VERSION_MAJOR;
  65         os_info.version_minor = OS_INFO_VERSION_MINOR;
  66         os_info.magic = OS_INFO_MAGIC;
  67         os_info.csum = os_info_csum(&os_info);
  68         abs_lc = get_abs_lowcore(&flags);
  69         abs_lc->os_info = __pa(&os_info);
  70         put_abs_lowcore(abs_lc, flags);
  71 }
  72
  73 #ifdef CONFIG_CRASH_DUMP
  74
  75 static struct os_info *os_info_old;
  76
  77 /*
  78  * Allocate and copy OS info entry from oldmem
  79  */
  80 static void os_info_old_alloc(int nr, int align)
  81 {
  82         unsigned long addr, size = 0;
  83         char *buf, *buf_align, *msg;
  84         u32 csum;
  85
  86         addr = os_info_old->entry[nr].addr;
  87         if (!addr) {
  88                 msg = "not available";
  89                 goto fail;
  90         }
  91         size = os_info_old->entry[nr].size;
  92         buf = kmalloc(size + align - 1, GFP_KERNEL);
  93         if (!buf) {
  94                 msg = "alloc failed";
  95                 goto fail;
  96         }
  97         buf_align = PTR_ALIGN(buf, align);
  98         if (copy_oldmem_kernel(buf_align, addr, size)) {
  99                 msg = "copy failed";
 100                 goto fail_free;
 101         }
 102         csum = (__force u32)csum_partial(buf_align, size, 0);
 103         if (csum != os_info_old->entry[nr].csum) {
 104                 msg = "checksum failed";
 105                 goto fail_free;
 106         }
 107         os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
 108         msg = "copied";
 109         goto out;
 110 fail_free:
 111         kfree(buf);
 112 fail:
 113         os_info_old->entry[nr].addr = 0;
 114 out:
 115         pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
 116                 nr, msg, addr, size);
 117 }
 118
 119 /*
 120  * Initialize os info and os info entries from oldmem
 121  */
 122 static void os_info_old_init(void)
 123 {
 124         static int os_info_init;
 125         unsigned long addr;
 126
 127         if (os_info_init)
 128                 return;
 129         if (!oldmem_data.start)
 130                 goto fail;
 131         if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
 132                 goto fail;
 133         if (addr == 0 || addr % PAGE_SIZE)
 134                 goto fail;
 135         os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
 136         if (!os_info_old)
 137                 goto fail;
 138         if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
 139                 goto fail_free;
 140         if (os_info_old->magic != OS_INFO_MAGIC)
 141                 goto fail_free;
 142         if (os_info_old->csum != os_info_csum(os_info_old))
 143                 goto fail_free;
 144         if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
 145                 goto fail_free;
 146         os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
 147         os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
 148         pr_info("crashkernel: addr=0x%lx size=%lu\n",
 149                 (unsigned long) os_info_old->crashkernel_addr,
 150                 (unsigned long) os_info_old->crashkernel_size);
 151         os_info_init = 1;
 152         return;
 153 fail_free:
 154         kfree(os_info_old);
 155 fail:
 156         os_info_init = 1;
 157         os_info_old = NULL;
 158 }
 159
 160 /*
 161  * Return pointer to os infor entry and its size
 162  */
 163 void *os_info_old_entry(int nr, unsigned long *size)
 164 {
 165         os_info_old_init();
 166
 167         if (!os_info_old)
 168                 return NULL;
 169         if (!os_info_old->entry[nr].addr)
 170                 return NULL;
 171         *size = (unsigned long) os_info_old->entry[nr].size;
 172         return (void *)(unsigned long)os_info_old->entry[nr].addr;
 173 }
 174 #endif