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_maps(unsigned long physmem, unsigned long iomem, unsigned long highmem)
  32 {
  33         struct page *p, *map;
  34         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
  35         unsigned long iomem_len, iomem_pages, total_len, total_pages;
  36         int i;
  37
  38         phys_pages = physmem >> PAGE_SHIFT;
  39         phys_len = phys_pages * sizeof(struct page);
  40
  41         iomem_pages = iomem >> PAGE_SHIFT;
  42         iomem_len = iomem_pages * sizeof(struct page);
  43
  44         highmem_pages = highmem >> PAGE_SHIFT;
  45         highmem_len = highmem_pages * sizeof(struct page);
  46
  47         total_pages = phys_pages + iomem_pages + highmem_pages;
  48         total_len = phys_len + iomem_len + highmem_len;
  49
  50         if(kmalloc_ok){
  51                 map = kmalloc(total_len, GFP_KERNEL);
  52                 if(map == NULL)
  53                         map = vmalloc(total_len);
  54         }
  55         else map = alloc_bootmem_low_pages(total_len);
  56
  57         if(map == NULL)
  58                 return -ENOMEM;
  59
  60         for(i = 0; i < total_pages; i++){
  61                 p = &map[i];
  62                 memset(p, 0, sizeof(struct page));
  63                 SetPageReserved(p);
  64                 INIT_LIST_HEAD(&p->lru);
  65         }
  66
  67         max_mapnr = total_pages;
  68         return 0;
  69 }
  70
  71 /* Changed during early boot */
  72 static unsigned long kmem_top = 0;
  73
  74 unsigned long get_kmem_end(void)
  75 {
  76         if(kmem_top == 0)
  77                 kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
  78         return kmem_top;
  79 }
  80
  81 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
  82                 int r, int w, int x)
  83 {
  84         __u64 offset;
  85         int fd, err;
  86
  87         fd = phys_mapping(phys, &offset);
  88         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
  89         if(err) {
  90                 if(err == -ENOMEM)
  91                         printk("try increasing the host's "
  92                                "/proc/sys/vm/max_map_count to <physical "
  93                                "memory size>/4096\n");
  94                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
  95                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
  96         }
  97 }
  98
  99 extern int __syscall_stub_start;
 100
 101 void setup_physmem(unsigned long start, unsigned long reserve_end,
 102                    unsigned long len, unsigned long long highmem)
 103 {
 104         unsigned long reserve = reserve_end - start;
 105         int pfn = PFN_UP(__pa(reserve_end));
 106         int delta = (len - reserve) >> PAGE_SHIFT;
 107         int err, offset, bootmap_size;
 108
 109         physmem_fd = create_mem_file(len + highmem);
 110
 111         offset = uml_reserved - uml_physmem;
 112         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 113                             len - offset, 1, 1, 0);
 114         if(err < 0){
 115                 os_print_error(err, "Mapping memory");
 116                 exit(1);
 117         }
 118
 119         /* Special kludge - This page will be mapped in to userspace processes
 120          * from physmem_fd, so it needs to be written out there.
 121          */
 122         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 123         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
 124
 125         bootmap_size = init_bootmem(pfn, pfn + delta);
 126         free_bootmem(__pa(reserve_end) + bootmap_size,
 127                      len - bootmap_size - reserve);
 128 }
 129
 130 int phys_mapping(unsigned long phys, __u64 *offset_out)
 131 {
 132         int fd = -1;
 133
 134         if(phys < physmem_size){
 135                 fd = physmem_fd;
 136                 *offset_out = phys;
 137         }
 138         else if(phys < __pa(end_iomem)){
 139                 struct iomem_region *region = iomem_regions;
 140
 141                 while(region != NULL){
 142                         if((phys >= region->phys) &&
 143                            (phys < region->phys + region->size)){
 144                                 fd = region->fd;
 145                                 *offset_out = phys - region->phys;
 146                                 break;
 147                         }
 148                         region = region->next;
 149                 }
 150         }
 151         else if(phys < __pa(end_iomem) + highmem){
 152                 fd = physmem_fd;
 153                 *offset_out = phys - iomem_size;
 154         }
 155
 156         return fd;
 157 }
 158
 159 static int __init uml_mem_setup(char *line, int *add)
 160 {
 161         char *retptr;
 162         physmem_size = memparse(line,&retptr);
 163         return 0;
 164 }
 165 __uml_setup("mem=", uml_mem_setup,
 166 "mem=<Amount of desired ram>\n"
 167 "    This controls how much \"physical\" memory the kernel allocates\n"
 168 "    for the system. The size is specified as a number followed by\n"
 169 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 170 "    This is not related to the amount of memory in the host.  It can\n"
 171 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 172 "       Example: mem=64M\n\n"
 173 );
 174
 175 extern int __init parse_iomem(char *str, int *add);
 176
 177 __uml_setup("iomem=", parse_iomem,
 178 "iomem=<name>,<file>\n"
 179 "    Configure <file> as an IO memory region named <name>.\n\n"
 180 );
 181
 182 /*
 183  * This list is constructed in parse_iomem and addresses filled in in
 184  * setup_iomem, both of which run during early boot.  Afterwards, it's
 185  * unchanged.
 186  */
 187 struct iomem_region *iomem_regions = NULL;
 188
 189 /* Initialized in parse_iomem */
 190 int iomem_size = 0;
 191
 192 unsigned long find_iomem(char *driver, unsigned long *len_out)
 193 {
 194         struct iomem_region *region = iomem_regions;
 195
 196         while(region != NULL){
 197                 if(!strcmp(region->driver, driver)){
 198                         *len_out = region->size;
 199                         return region->virt;
 200                 }
 201
 202                 region = region->next;
 203         }
 204
 205         return 0;
 206 }
 207
 208 int setup_iomem(void)
 209 {
 210         struct iomem_region *region = iomem_regions;
 211         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 212         int err;
 213
 214         while(region != NULL){
 215                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 216                                     region->size, 1, 1, 0);
 217                 if(err)
 218                         printk("Mapping iomem region for driver '%s' failed, "
 219                                "errno = %d\n", region->driver, -err);
 220                 else {
 221                         region->virt = iomem_start;
 222                         region->phys = __pa(region->virt);
 223                 }
 224
 225                 iomem_start += region->size + PAGE_SIZE;
 226                 region = region->next;
 227         }
 228
 229         return 0;
 230 }
 231
 232 __initcall(setup_iomem);