arch/x86/multiboot.c

   1 /* Support for Multiboot */
   2
   3 #include "config.h"
   4 #include "asm/io.h"
   5 #include "libopenbios/sys_info.h"
   6 #include "multiboot.h"
   7
   8 #ifdef CONFIG_DEBUG_BOOT
   9 #define debug printk
  10 #else
  11 #define debug(x...)
  12 #endif
  13
  14 struct mbheader {
  15     unsigned int magic, flags, checksum;
  16 };
  17
  18 static const struct mbheader multiboot_header
  19         __attribute__((section (".hdr"))) =
  20 {
  21     MULTIBOOT_HEADER_MAGIC,
  22     MULTIBOOT_HEADER_FLAGS,
  23     -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
  24 };
  25
  26 /* Multiboot information structure, provided by loader to us */
  27
  28 struct multiboot_mmap {
  29         unsigned entry_size;
  30         unsigned base_lo, base_hi;
  31         unsigned size_lo, size_hi;
  32         unsigned type;
  33 };
  34
  35 #define MULTIBOOT_MEM_VALID       0x01
  36 #define MULTIBOOT_BOOT_DEV_VALID  0x02
  37 #define MULTIBOOT_CMDLINE_VALID   0x04
  38 #define MULTIBOOT_MODS_VALID      0x08
  39 #define MULTIBOOT_AOUT_SYMS_VALID 0x10
  40 #define MULTIBOOT_ELF_SYMS_VALID  0x20
  41 #define MULTIBOOT_MMAP_VALID      0x40
  42
  43 void collect_multiboot_info(struct sys_info *info);
  44 void collect_multiboot_info(struct sys_info *info)
  45 {
  46     struct multiboot_info *mbinfo;
  47     struct multiboot_mmap *mbmem;
  48     unsigned mbcount, mbaddr;
  49     int i;
  50     struct memrange *mmap;
  51     int mmap_count;
  52     module_t *mod;
  53
  54     if (info->boot_type != 0x2BADB002)
  55         return;
  56
  57     debug("Using Multiboot information at %#lx\n", info->boot_data);
  58
  59     mbinfo = phys_to_virt(info->boot_data);
  60
  61     if (mbinfo->mods_count != 1) {
  62             printk("multiboot: no dictionary\n");
  63             return;
  64     }
  65
  66     mod = (module_t *) mbinfo->mods_addr;
  67     info->dict_start=(unsigned long *)mod->mod_start;
  68     info->dict_end=(unsigned long *)mod->mod_end;
  69     debug("multiboot: dictionary at %p-%p\n",
  70                     info->dict_start, info->dict_end);
  71
  72     if (mbinfo->flags & MULTIBOOT_MMAP_VALID) {
  73         /* convert mmap records */
  74         mbmem = phys_to_virt(mbinfo->mmap_addr);
  75         mbcount = mbinfo->mmap_length / (mbmem->entry_size + 4);
  76         mmap = malloc(mbcount * sizeof(struct memrange));
  77         mmap_count = 0;
  78         mbaddr = mbinfo->mmap_addr;
  79         for (i = 0; i < mbcount; i++) {
  80             mbmem = phys_to_virt(mbaddr);
  81             debug("%08x%08x %08x%08x (%d)\n",
  82                     mbmem->base_hi,
  83                     mbmem->base_lo,
  84                     mbmem->size_hi,
  85                     mbmem->size_lo,
  86                     mbmem->type);
  87             if (mbmem->type == 1) { /* Only normal RAM */
  88                 mmap[mmap_count].base = mbmem->base_lo
  89                     + (((unsigned long long) mbmem->base_hi) << 32);
  90                 mmap[mmap_count].size = mbmem->size_lo
  91                     + (((unsigned long long) mbmem->size_hi) << 32);
  92                 mmap_count++;
  93             }
  94             mbaddr += mbmem->entry_size + 4;
  95             if (mbaddr >= mbinfo->mmap_addr + mbinfo->mmap_length)
  96                 break;
  97         }
  98         /* simple sanity check - there should be at least 2 RAM segments
  99          * (base 640k and extended) */
 100         if (mmap_count >= 2)
 101             goto got_it;
 102
 103         printk("Multiboot mmap is broken\n");
 104         free(mmap);
 105         /* fall back to mem_lower/mem_upper */
 106     }
 107
 108     if (mbinfo->flags & MULTIBOOT_MEM_VALID) {
 109         /* use mem_lower and mem_upper */
 110         mmap_count = 2;
 111         mmap = malloc(2 * sizeof(*mmap));
 112         mmap[0].base = 0;
 113         mmap[0].size = mbinfo->mem_lower << 10;
 114         mmap[1].base = 1 << 20; /* 1MB */
 115         mmap[1].size = mbinfo->mem_upper << 10;
 116         goto got_it;
 117     }
 118
 119     printk("Can't get memory information from Multiboot\n");
 120     return;
 121
 122 got_it:
 123     info->memrange = mmap;
 124     info->n_memranges = mmap_count;
 125
 126     return;
 127 }