arch/um/kernel/physmem.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/bootmem.h"
   7 #include "linux/mm.h"
   8 #include "linux/pfn.h"
   9 #include "asm/page.h"
  10 #include "as-layout.h"
  11 #include "init.h"
  12 #include "kern.h"
  13 #include "mem_user.h"
  14 #include "os.h"
  15
  16 static int physmem_fd = -1;
  17
  18 /* Changed during early boot */
  19 unsigned long high_physmem;
  20
  21 extern unsigned long long physmem_size;
  22
  23 int __init init_maps(unsigned long physmem, unsigned long iomem,
  24                      unsigned long highmem)
  25 {
  26         struct page *p, *map;
  27         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
  28         unsigned long iomem_len, iomem_pages, total_len, total_pages;
  29         int i;
  30
  31         phys_pages = physmem >> PAGE_SHIFT;
  32         phys_len = phys_pages * sizeof(struct page);
  33
  34         iomem_pages = iomem >> PAGE_SHIFT;
  35         iomem_len = iomem_pages * sizeof(struct page);
  36
  37         highmem_pages = highmem >> PAGE_SHIFT;
  38         highmem_len = highmem_pages * sizeof(struct page);
  39
  40         total_pages = phys_pages + iomem_pages + highmem_pages;
  41         total_len = phys_len + iomem_len + highmem_len;
  42
  43         map = alloc_bootmem_low_pages(total_len);
  44         if (map == NULL)
  45                 return -ENOMEM;
  46
  47         for (i = 0; i < total_pages; i++) {
  48                 p = &map[i];
  49                 memset(p, 0, sizeof(struct page));
  50                 SetPageReserved(p);
  51                 INIT_LIST_HEAD(&p->lru);
  52         }
  53
  54         max_mapnr = total_pages;
  55         return 0;
  56 }
  57
  58 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
  59                 int r, int w, int x)
  60 {
  61         __u64 offset;
  62         int fd, err;
  63
  64         fd = phys_mapping(phys, &offset);
  65         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
  66         if (err) {
  67                 if (err == -ENOMEM)
  68                         printk(KERN_ERR "try increasing the host's "
  69                                "/proc/sys/vm/max_map_count to <physical "
  70                                "memory size>/4096\n");
  71                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
  72                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
  73         }
  74 }
  75
  76 extern int __syscall_stub_start;
  77
  78 void __init setup_physmem(unsigned long start, unsigned long reserve_end,
  79                           unsigned long len, unsigned long long highmem)
  80 {
  81         unsigned long reserve = reserve_end - start;
  82         int pfn = PFN_UP(__pa(reserve_end));
  83         int delta = (len - reserve) >> PAGE_SHIFT;
  84         int err, offset, bootmap_size;
  85
  86         physmem_fd = create_mem_file(len + highmem);
  87
  88         offset = uml_reserved - uml_physmem;
  89         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
  90                             len - offset, 1, 1, 1);
  91         if (err < 0) {
  92                 printf("setup_physmem - mapping %ld bytes of memory at 0x%p "
  93                        "failed - errno = %d\n", len - offset,
  94                        (void *) uml_reserved, err);
  95                 exit(1);
  96         }
  97
  98         /*
  99          * Special kludge - This page will be mapped in to userspace processes
 100          * from physmem_fd, so it needs to be written out there.
 101          */
 102         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 103         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
 104
 105         bootmap_size = init_bootmem(pfn, pfn + delta);
 106         free_bootmem(__pa(reserve_end) + bootmap_size,
 107                      len - bootmap_size - reserve);
 108 }
 109
 110 int phys_mapping(unsigned long phys, unsigned long long *offset_out)
 111 {
 112         int fd = -1;
 113
 114         if (phys < physmem_size) {
 115                 fd = physmem_fd;
 116                 *offset_out = phys;
 117         }
 118         else if (phys < __pa(end_iomem)) {
 119                 struct iomem_region *region = iomem_regions;
 120
 121                 while (region != NULL) {
 122                         if ((phys >= region->phys) &&
 123                             (phys < region->phys + region->size)) {
 124                                 fd = region->fd;
 125                                 *offset_out = phys - region->phys;
 126                                 break;
 127                         }
 128                         region = region->next;
 129                 }
 130         }
 131         else if (phys < __pa(end_iomem) + highmem) {
 132                 fd = physmem_fd;
 133                 *offset_out = phys - iomem_size;
 134         }
 135
 136         return fd;
 137 }
 138
 139 static int __init uml_mem_setup(char *line, int *add)
 140 {
 141         char *retptr;
 142         physmem_size = memparse(line,&retptr);
 143         return 0;
 144 }
 145 __uml_setup("mem=", uml_mem_setup,
 146 "mem=<Amount of desired ram>\n"
 147 "    This controls how much \"physical\" memory the kernel allocates\n"
 148 "    for the system. The size is specified as a number followed by\n"
 149 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 150 "    This is not related to the amount of memory in the host.  It can\n"
 151 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 152 "       Example: mem=64M\n\n"
 153 );
 154
 155 extern int __init parse_iomem(char *str, int *add);
 156
 157 __uml_setup("iomem=", parse_iomem,
 158 "iomem=<name>,<file>\n"
 159 "    Configure <file> as an IO memory region named <name>.\n\n"
 160 );
 161
 162 /*
 163  * This list is constructed in parse_iomem and addresses filled in in
 164  * setup_iomem, both of which run during early boot.  Afterwards, it's
 165  * unchanged.
 166  */
 167 struct iomem_region *iomem_regions;
 168
 169 /* Initialized in parse_iomem and unchanged thereafter */
 170 int iomem_size;
 171
 172 unsigned long find_iomem(char *driver, unsigned long *len_out)
 173 {
 174         struct iomem_region *region = iomem_regions;
 175
 176         while (region != NULL) {
 177                 if (!strcmp(region->driver, driver)) {
 178                         *len_out = region->size;
 179                         return region->virt;
 180                 }
 181
 182                 region = region->next;
 183         }
 184
 185         return 0;
 186 }
 187
 188 int setup_iomem(void)
 189 {
 190         struct iomem_region *region = iomem_regions;
 191         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 192         int err;
 193
 194         while (region != NULL) {
 195                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 196                                     region->size, 1, 1, 0);
 197                 if (err)
 198                         printk(KERN_ERR "Mapping iomem region for driver '%s' "
 199                                "failed, errno = %d\n", region->driver, -err);
 200                 else {
 201                         region->virt = iomem_start;
 202                         region->phys = __pa(region->virt);
 203                 }
 204
 205                 iomem_start += region->size + PAGE_SIZE;
 206                 region = region->next;
 207         }
 208
 209         return 0;
 210 }
 211
 212 __initcall(setup_iomem);