kernel/arch/x86/multiboot.cc

   1 // arch/x86/multiboot.cc -- Code to interpret multiboot data and initialize
   2 //                          free memory regions based thereupon.
   3 //
   4 // This software is copyright (c) 2006 Scott Wood <scott@buserror.net>.
   5 //
   6 // Permission is hereby granted, free of charge, to any person obtaining a copy of
   7 // this software and associated documentation files (the "Software"), to deal with
   8 // the Software without restriction, including without limitation the rights to
   9 // use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  10 // of the Software, and to permit persons to whom the Software is furnished to do
  11 // so, subject to the following condition:
  12 //
  13 // The above copyright notice and this permission notice shall be
  14 // included in all copies or substantial portions of the Software.
  15 //
  16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  18 // FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  19 // CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
  22 // SOFTWARE.
  23
  24 #include <kern/libc.h>
  25 #include <kern/pagealloc.h>
  26
  27 #include <arch/multiboot.h>
  28 #include <arch/addrs.h>
  29 #include <arch/paging.h>
  30 #include <arch/mem.h>
  31
  32 #include <util/misc.h>
  33 #include <limits.h>
  34
  35 u32 x86_boot_info_phys;
  36 extern int _start;
  37
  38 namespace Arch {
  39 namespace Priv {
  40 namespace MultiBoot {
  41         BootInfo *boot_info;
  42
  43         void parse_mmap()
  44         {
  45         }
  46
  47         using Util::round_up;
  48         using Util::round_down;
  49
  50         void make_mem_avail(u64 start, u64 end)
  51         {
  52                 using Mem::pages;
  53
  54                 if (start > end)
  55                         return;
  56
  57                 for (int i = 0; i < num_zones; i++) {
  58                         u64 rstart = mem_zone_regions[i].start;
  59                         u64 rend = mem_zone_regions[i].end;
  60
  61                         if (start <= rend && end >= rstart) {
  62                                 if (rstart < start)
  63                                         rstart = start;
  64                                 if (rend > end)
  65                                         rend = end;
  66
  67                                 ulong page_len = (rend - rstart + 1) / page_size;
  68                                 pagezones[i].free(Mem::phys_to_page(rstart), page_len);
  69                         }
  70                 }
  71         }
  72
  73         void process_info()
  74         {
  75                 if (x86_boot_info_phys > max_ktext_map) {
  76                         printf("Cannot access boot info at %#.8x\n", x86_boot_info_phys);
  77                         for(;;);
  78                 }
  79
  80                 boot_info = (BootInfo *)phys_to_kvirt(x86_boot_info_phys);
  81                 mem_end = 0;
  82
  83                 if (!(boot_info->flags & (1 << BootInfo::flag_mmap))) {
  84                         // FIXME: use mem_lower and mem_upper in this case.
  85                         printf("MultiBoot info does not contain a memory map.\n");
  86                         for(;;);
  87                 }
  88
  89                 printf("BIOS Memory Map:\n");
  90
  91                 uint off = 0;
  92                 while (off < boot_info->mmap_length) {
  93                         u32 phys = boot_info->mmap_addr + off;
  94
  95                         if (phys > max_ktext_map) {
  96                                 printf("Cannot access BIOS memory map entry at %#.8x\n", phys);
  97                                 for(;;);
  98                         }
  99
 100                         MemMap *mmap = (MemMap *)phys_to_kvirt(phys);
 101
 102                         printf("0x%016llx - 0x%016llx, type %d\n",
 103                                mmap->base, mmap->base + mmap->len - 1, mmap->type);
 104
 105                         off += mmap->size + 4;
 106
 107                         if (mmap->type == MemMap::Available) {
 108                                 u64 end = mmap->base + mmap->len;
 109
 110                                 if (end > mem_end)
 111                                         mem_end = end;
 112                         }
 113                 }
 114
 115                 map_physmem();
 116
 117                 // Don't make available any pages that overlap the
 118                 // kernel text/data or bootmem allocations.
 119
 120                 u64 kernelstart = round_down(kvirt_to_phys(&_start), page_shift);
 121                 u64 kernelend = round_up(kvirt_to_phys((void *)next_free_bootmem),
 122                                          page_shift) - 1;
 123
 124                 off = 0;
 125                 while (off < boot_info->mmap_length) {
 126                         u32 phys = boot_info->mmap_addr + off;
 127                         MemMap *mmap = (MemMap *)phys_to_kvirt(phys);
 128                         off += mmap->size + 4;
 129
 130                         if (mmap->type == MemMap::Available) {
 131                                 // Don't use any page that isn't fully in this entry.
 132
 133                                 u64 start = round_up(mmap->base, page_shift);
 134                                 u64 end = round_down(mmap->base + mmap->len, page_shift) - 1;
 135
 136                                 // Don't overwrite page 1; the BIOS will need it for later calls in
 137                                 // emulation, and at least the BIOS I'm testing on doesn't mark
 138                                 // it as reserved.
 139
 140                                 if (start < page_size)
 141                                         start = page_size;
 142
 143                                 if (start <= kernelend && end >= kernelstart) {
 144                                         if (start < kernelstart)
 145                                                 make_mem_avail(start, kernelstart - 1);
 146
 147                                         if (end > kernelend)
 148                                                 make_mem_avail(kernelend + 1, end);
 149                                 } else {
 150                                         make_mem_avail(start, end);
 151                                 }
 152                         }
 153                 }
 154         }
 155 }
 156 }
 157 }