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/physmem_info.h>
  19 #include <asm/maccess.h>
  20 #include <asm/asm-offsets.h>
  21 #include <asm/ipl.h>
  22
  23 /*
  24  * OS info structure has to be page aligned
  25  */
  26 static struct os_info os_info __page_aligned_data;
  27
  28 /*
  29  * Compute checksum over OS info structure
  30  */
  31 u32 os_info_csum(struct os_info *os_info)
  32 {
  33         int size = sizeof(*os_info) - offsetof(struct os_info, version_major);
  34         return (__force u32)cksm(&os_info->version_major, size, 0);
  35 }
  36
  37 /*
  38  * Add crashkernel info to OS info and update checksum
  39  */
  40 void os_info_crashkernel_add(unsigned long base, unsigned long size)
  41 {
  42         os_info.crashkernel_addr = (u64)(unsigned long)base;
  43         os_info.crashkernel_size = (u64)(unsigned long)size;
  44         os_info.csum = os_info_csum(&os_info);
  45 }
  46
  47 /*
  48  * Add OS info data entry and update checksum
  49  */
  50 void os_info_entry_add_data(int nr, void *ptr, u64 size)
  51 {
  52         os_info.entry[nr].addr = __pa(ptr);
  53         os_info.entry[nr].size = size;
  54         os_info.entry[nr].csum = (__force u32)cksm(ptr, size, 0);
  55         os_info.csum = os_info_csum(&os_info);
  56 }
  57
  58 /*
  59  * Add OS info value entry and update checksum
  60  */
  61 void os_info_entry_add_val(int nr, u64 value)
  62 {
  63         os_info.entry[nr].val = value;
  64         os_info.entry[nr].size = 0;
  65         os_info.entry[nr].csum = 0;
  66         os_info.csum = os_info_csum(&os_info);
  67 }
  68
  69 /*
  70  * Initialize OS info structure and set lowcore pointer
  71  */
  72 void __init os_info_init(void)
  73 {
  74         struct lowcore *abs_lc;
  75
  76         BUILD_BUG_ON(sizeof(struct os_info) != PAGE_SIZE);
  77         os_info.version_major = OS_INFO_VERSION_MAJOR;
  78         os_info.version_minor = OS_INFO_VERSION_MINOR;
  79         os_info.magic = OS_INFO_MAGIC;
  80         os_info_entry_add_val(OS_INFO_IDENTITY_BASE, __identity_base);
  81         os_info_entry_add_val(OS_INFO_KASLR_OFFSET, kaslr_offset());
  82         os_info_entry_add_val(OS_INFO_KASLR_OFF_PHYS, __kaslr_offset_phys);
  83         os_info_entry_add_val(OS_INFO_VMEMMAP, (unsigned long)vmemmap);
  84         os_info_entry_add_val(OS_INFO_AMODE31_START, AMODE31_START);
  85         os_info_entry_add_val(OS_INFO_AMODE31_END, AMODE31_END);
  86         os_info_entry_add_val(OS_INFO_IMAGE_START, (unsigned long)_stext);
  87         os_info_entry_add_val(OS_INFO_IMAGE_END, (unsigned long)_end);
  88         os_info_entry_add_val(OS_INFO_IMAGE_PHYS, __pa_symbol(_stext));
  89         os_info.csum = os_info_csum(&os_info);
  90         abs_lc = get_abs_lowcore();
  91         abs_lc->os_info = __pa(&os_info);
  92         put_abs_lowcore(abs_lc);
  93 }
  94
  95 #ifdef CONFIG_CRASH_DUMP
  96
  97 static struct os_info *os_info_old;
  98
  99 /*
 100  * Allocate and copy OS info entry from oldmem
 101  */
 102 static void os_info_old_alloc(int nr, int align)
 103 {
 104         unsigned long addr, size = 0;
 105         char *buf, *buf_align, *msg;
 106         u32 csum;
 107
 108         addr = os_info_old->entry[nr].addr;
 109         if (!addr) {
 110                 msg = "not available";
 111                 goto fail;
 112         }
 113         size = os_info_old->entry[nr].size;
 114         buf = kmalloc(size + align - 1, GFP_KERNEL);
 115         if (!buf) {
 116                 msg = "alloc failed";
 117                 goto fail;
 118         }
 119         buf_align = PTR_ALIGN(buf, align);
 120         if (copy_oldmem_kernel(buf_align, addr, size)) {
 121                 msg = "copy failed";
 122                 goto fail_free;
 123         }
 124         csum = (__force u32)cksm(buf_align, size, 0);
 125         if (csum != os_info_old->entry[nr].csum) {
 126                 msg = "checksum failed";
 127                 goto fail_free;
 128         }
 129         os_info_old->entry[nr].addr = (u64)(unsigned long)buf_align;
 130         msg = "copied";
 131         goto out;
 132 fail_free:
 133         kfree(buf);
 134 fail:
 135         os_info_old->entry[nr].addr = 0;
 136 out:
 137         pr_info("entry %i: %s (addr=0x%lx size=%lu)\n",
 138                 nr, msg, addr, size);
 139 }
 140
 141 /*
 142  * Initialize os info and os info entries from oldmem
 143  */
 144 static void os_info_old_init(void)
 145 {
 146         static int os_info_init;
 147         unsigned long addr;
 148
 149         if (os_info_init)
 150                 return;
 151         if (!oldmem_data.start && !is_ipl_type_dump())
 152                 goto fail;
 153         if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
 154                 goto fail;
 155         if (addr == 0 || addr % PAGE_SIZE)
 156                 goto fail;
 157         os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
 158         if (!os_info_old)
 159                 goto fail;
 160         if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
 161                 goto fail_free;
 162         if (os_info_old->magic != OS_INFO_MAGIC)
 163                 goto fail_free;
 164         if (os_info_old->csum != os_info_csum(os_info_old))
 165                 goto fail_free;
 166         if (os_info_old->version_major > OS_INFO_VERSION_MAJOR)
 167                 goto fail_free;
 168         os_info_old_alloc(OS_INFO_VMCOREINFO, 1);
 169         os_info_old_alloc(OS_INFO_REIPL_BLOCK, 1);
 170         pr_info("crashkernel: addr=0x%lx size=%lu\n",
 171                 (unsigned long) os_info_old->crashkernel_addr,
 172                 (unsigned long) os_info_old->crashkernel_size);
 173         os_info_init = 1;
 174         return;
 175 fail_free:
 176         kfree(os_info_old);
 177 fail:
 178         os_info_init = 1;
 179         os_info_old = NULL;
 180 }
 181
 182 /*
 183  * Return pointer to os info entry and its size
 184  */
 185 void *os_info_old_entry(int nr, unsigned long *size)
 186 {
 187         os_info_old_init();
 188
 189         if (!os_info_old)
 190                 return NULL;
 191         if (!os_info_old->entry[nr].addr)
 192                 return NULL;
 193         *size = (unsigned long) os_info_old->entry[nr].size;
 194         return (void *)(unsigned long)os_info_old->entry[nr].addr;
 195 }
 196 #endif