arch/um/kernel/physmem.c

   1 /*
   2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/mm.h"
   7 #include "linux/rbtree.h"
   8 #include "linux/slab.h"
   9 #include "linux/vmalloc.h"
  10 #include "linux/bootmem.h"
  11 #include "linux/module.h"
  12 #include "linux/pfn.h"
  13 #include "asm/types.h"
  14 #include "asm/pgtable.h"
  15 #include "kern_util.h"
  16 #include "as-layout.h"
  17 #include "mode_kern.h"
  18 #include "mem.h"
  19 #include "mem_user.h"
  20 #include "os.h"
  21 #include "kern.h"
  22 #include "init.h"
  23
  24 static int physmem_fd = -1;
  25
  26 /* Changed during early boot */
  27 unsigned long high_physmem;
  28
  29 extern unsigned long long physmem_size;
  30
  31 int __init init_maps(unsigned long physmem, unsigned long iomem,
  32                      unsigned long highmem)
  33 {
  34         struct page *p, *map;
  35         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
  36         unsigned long iomem_len, iomem_pages, total_len, total_pages;
  37         int i;
  38
  39         phys_pages = physmem >> PAGE_SHIFT;
  40         phys_len = phys_pages * sizeof(struct page);
  41
  42         iomem_pages = iomem >> PAGE_SHIFT;
  43         iomem_len = iomem_pages * sizeof(struct page);
  44
  45         highmem_pages = highmem >> PAGE_SHIFT;
  46         highmem_len = highmem_pages * sizeof(struct page);
  47
  48         total_pages = phys_pages + iomem_pages + highmem_pages;
  49         total_len = phys_len + iomem_len + highmem_len;
  50
  51         map = alloc_bootmem_low_pages(total_len);
  52         if(map == NULL)
  53                 return -ENOMEM;
  54
  55         for(i = 0; i < total_pages; i++){
  56                 p = &map[i];
  57                 memset(p, 0, sizeof(struct page));
  58                 SetPageReserved(p);
  59                 INIT_LIST_HEAD(&p->lru);
  60         }
  61
  62         max_mapnr = total_pages;
  63         return 0;
  64 }
  65
  66 /* Changed during early boot */
  67 static unsigned long kmem_top = 0;
  68
  69 unsigned long get_kmem_end(void)
  70 {
  71         if(kmem_top == 0)
  72                 kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
  73         return kmem_top;
  74 }
  75
  76 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
  77                 int r, int w, int x)
  78 {
  79         __u64 offset;
  80         int fd, err;
  81
  82         fd = phys_mapping(phys, &offset);
  83         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
  84         if(err) {
  85                 if(err == -ENOMEM)
  86                         printk("try increasing the host's "
  87                                "/proc/sys/vm/max_map_count to <physical "
  88                                "memory size>/4096\n");
  89                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
  90                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
  91         }
  92 }
  93
  94 extern int __syscall_stub_start;
  95
  96 void __init setup_physmem(unsigned long start, unsigned long reserve_end,
  97                           unsigned long len, unsigned long long highmem)
  98 {
  99         unsigned long reserve = reserve_end - start;
 100         int pfn = PFN_UP(__pa(reserve_end));
 101         int delta = (len - reserve) >> PAGE_SHIFT;
 102         int err, offset, bootmap_size;
 103
 104         physmem_fd = create_mem_file(len + highmem);
 105
 106         offset = uml_reserved - uml_physmem;
 107         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 108                             len - offset, 1, 1, 1);
 109         if(err < 0){
 110                 os_print_error(err, "Mapping memory");
 111                 exit(1);
 112         }
 113
 114         /* Special kludge - This page will be mapped in to userspace processes
 115          * from physmem_fd, so it needs to be written out there.
 116          */
 117         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 118         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
 119
 120         bootmap_size = init_bootmem(pfn, pfn + delta);
 121         free_bootmem(__pa(reserve_end) + bootmap_size,
 122                      len - bootmap_size - reserve);
 123 }
 124
 125 int phys_mapping(unsigned long phys, __u64 *offset_out)
 126 {
 127         int fd = -1;
 128
 129         if(phys < physmem_size){
 130                 fd = physmem_fd;
 131                 *offset_out = phys;
 132         }
 133         else if(phys < __pa(end_iomem)){
 134                 struct iomem_region *region = iomem_regions;
 135
 136                 while(region != NULL){
 137                         if((phys >= region->phys) &&
 138                            (phys < region->phys + region->size)){
 139                                 fd = region->fd;
 140                                 *offset_out = phys - region->phys;
 141                                 break;
 142                         }
 143                         region = region->next;
 144                 }
 145         }
 146         else if(phys < __pa(end_iomem) + highmem){
 147                 fd = physmem_fd;
 148                 *offset_out = phys - iomem_size;
 149         }
 150
 151         return fd;
 152 }
 153
 154 static int __init uml_mem_setup(char *line, int *add)
 155 {
 156         char *retptr;
 157         physmem_size = memparse(line,&retptr);
 158         return 0;
 159 }
 160 __uml_setup("mem=", uml_mem_setup,
 161 "mem=<Amount of desired ram>\n"
 162 "    This controls how much \"physical\" memory the kernel allocates\n"
 163 "    for the system. The size is specified as a number followed by\n"
 164 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 165 "    This is not related to the amount of memory in the host.  It can\n"
 166 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 167 "       Example: mem=64M\n\n"
 168 );
 169
 170 extern int __init parse_iomem(char *str, int *add);
 171
 172 __uml_setup("iomem=", parse_iomem,
 173 "iomem=<name>,<file>\n"
 174 "    Configure <file> as an IO memory region named <name>.\n\n"
 175 );
 176
 177 /*
 178  * This list is constructed in parse_iomem and addresses filled in in
 179  * setup_iomem, both of which run during early boot.  Afterwards, it's
 180  * unchanged.
 181  */
 182 struct iomem_region *iomem_regions = NULL;
 183
 184 /* Initialized in parse_iomem */
 185 int iomem_size = 0;
 186
 187 unsigned long find_iomem(char *driver, unsigned long *len_out)
 188 {
 189         struct iomem_region *region = iomem_regions;
 190
 191         while(region != NULL){
 192                 if(!strcmp(region->driver, driver)){
 193                         *len_out = region->size;
 194                         return region->virt;
 195                 }
 196
 197                 region = region->next;
 198         }
 199
 200         return 0;
 201 }
 202
 203 int setup_iomem(void)
 204 {
 205         struct iomem_region *region = iomem_regions;
 206         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 207         int err;
 208
 209         while(region != NULL){
 210                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 211                                     region->size, 1, 1, 0);
 212                 if(err)
 213                         printk("Mapping iomem region for driver '%s' failed, "
 214                                "errno = %d\n", region->driver, -err);
 215                 else {
 216                         region->virt = iomem_start;
 217                         region->phys = __pa(region->virt);
 218                 }
 219
 220                 iomem_start += region->size + PAGE_SIZE;
 221                 region = region->next;
 222         }
 223
 224         return 0;
 225 }
 226
 227 __initcall(setup_iomem);