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