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 void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
  26                      unsigned long highmem)
  27 {
  28         unsigned long phys_pages, highmem_pages;
  29         unsigned long iomem_pages, total_pages;
  30
  31         phys_pages    = physmem >> PAGE_SHIFT;
  32         iomem_pages   = iomem   >> PAGE_SHIFT;
  33         highmem_pages = highmem >> PAGE_SHIFT;
  34
  35         total_pages   = phys_pages + iomem_pages + highmem_pages;
  36
  37         max_mapnr = total_pages;
  38 }
  39
  40 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
  41                 int r, int w, int x)
  42 {
  43         __u64 offset;
  44         int fd, err;
  45
  46         fd = phys_mapping(phys, &offset);
  47         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
  48         if (err) {
  49                 if (err == -ENOMEM)
  50                         printk(KERN_ERR "try increasing the host's "
  51                                "/proc/sys/vm/max_map_count to <physical "
  52                                "memory size>/4096\n");
  53                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
  54                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
  55         }
  56 }
  57
  58 extern int __syscall_stub_start;
  59
  60 /**
  61  * setup_physmem() - Setup physical memory for UML
  62  * @start:      Start address of the physical kernel memory,
  63  *              i.e start address of the executable image.
  64  * @reserve_end:        end address of the physical kernel memory.
  65  * @len:        Length of total physical memory that should be mapped/made
  66  *              available, in bytes.
  67  * @highmem:    Number of highmem bytes that should be mapped/made available.
  68  *
  69  * Creates an unlinked temporary file of size (len + highmem) and memory maps
  70  * it on the last executable image address (uml_reserved).
  71  *
  72  * The offset is needed as the length of the total physical memory
  73  * (len + highmem) includes the size of the memory used be the executable image,
  74  * but the mapped-to address is the last address of the executable image
  75  * (uml_reserved == end address of executable image).
  76  *
  77  * The memory mapped memory of the temporary file is used as backing memory
  78  * of all user space processes/kernel tasks.
  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         unsigned long pfn = PFN_UP(__pa(reserve_end));
  85         unsigned long delta = (len - reserve) >> PAGE_SHIFT;
  86         unsigned long offset, bootmap_size;
  87         long map_size;
  88         int err;
  89
  90         offset = uml_reserved - uml_physmem;
  91         map_size = len - offset;
  92         if(map_size <= 0) {
  93                 printf("Too few physical memory! Needed=%d, given=%d\n",
  94                        offset, len);
  95                 exit(1);
  96         }
  97
  98         physmem_fd = create_mem_file(len + highmem);
  99
 100         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 101                             map_size, 1, 1, 1);
 102         if (err < 0) {
 103                 printf("setup_physmem - mapping %ld bytes of memory at 0x%p "
 104                        "failed - errno = %d\n", map_size,
 105                        (void *) uml_reserved, err);
 106                 exit(1);
 107         }
 108
 109         /*
 110          * Special kludge - This page will be mapped in to userspace processes
 111          * from physmem_fd, so it needs to be written out there.
 112          */
 113         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 114         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
 115         os_fsync_file(physmem_fd);
 116
 117         bootmap_size = init_bootmem(pfn, pfn + delta);
 118         free_bootmem(__pa(reserve_end) + bootmap_size,
 119                      len - bootmap_size - reserve);
 120 }
 121
 122 int phys_mapping(unsigned long phys, unsigned long long *offset_out)
 123 {
 124         int fd = -1;
 125
 126         if (phys < physmem_size) {
 127                 fd = physmem_fd;
 128                 *offset_out = phys;
 129         }
 130         else if (phys < __pa(end_iomem)) {
 131                 struct iomem_region *region = iomem_regions;
 132
 133                 while (region != NULL) {
 134                         if ((phys >= region->phys) &&
 135                             (phys < region->phys + region->size)) {
 136                                 fd = region->fd;
 137                                 *offset_out = phys - region->phys;
 138                                 break;
 139                         }
 140                         region = region->next;
 141                 }
 142         }
 143         else if (phys < __pa(end_iomem) + highmem) {
 144                 fd = physmem_fd;
 145                 *offset_out = phys - iomem_size;
 146         }
 147
 148         return fd;
 149 }
 150
 151 static int __init uml_mem_setup(char *line, int *add)
 152 {
 153         char *retptr;
 154         physmem_size = memparse(line,&retptr);
 155         return 0;
 156 }
 157 __uml_setup("mem=", uml_mem_setup,
 158 "mem=<Amount of desired ram>\n"
 159 "    This controls how much \"physical\" memory the kernel allocates\n"
 160 "    for the system. The size is specified as a number followed by\n"
 161 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 162 "    This is not related to the amount of memory in the host.  It can\n"
 163 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 164 "       Example: mem=64M\n\n"
 165 );
 166
 167 extern int __init parse_iomem(char *str, int *add);
 168
 169 __uml_setup("iomem=", parse_iomem,
 170 "iomem=<name>,<file>\n"
 171 "    Configure <file> as an IO memory region named <name>.\n\n"
 172 );
 173
 174 /*
 175  * This list is constructed in parse_iomem and addresses filled in in
 176  * setup_iomem, both of which run during early boot.  Afterwards, it's
 177  * unchanged.
 178  */
 179 struct iomem_region *iomem_regions;
 180
 181 /* Initialized in parse_iomem and unchanged thereafter */
 182 int iomem_size;
 183
 184 unsigned long find_iomem(char *driver, unsigned long *len_out)
 185 {
 186         struct iomem_region *region = iomem_regions;
 187
 188         while (region != NULL) {
 189                 if (!strcmp(region->driver, driver)) {
 190                         *len_out = region->size;
 191                         return region->virt;
 192                 }
 193
 194                 region = region->next;
 195         }
 196
 197         return 0;
 198 }
 199 EXPORT_SYMBOL(find_iomem);
 200
 201 static int setup_iomem(void)
 202 {
 203         struct iomem_region *region = iomem_regions;
 204         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 205         int err;
 206
 207         while (region != NULL) {
 208                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 209                                     region->size, 1, 1, 0);
 210                 if (err)
 211                         printk(KERN_ERR "Mapping iomem region for driver '%s' "
 212                                "failed, errno = %d\n", region->driver, -err);
 213                 else {
 214                         region->virt = iomem_start;
 215                         region->phys = __pa(region->virt);
 216                 }
 217
 218                 iomem_start += region->size + PAGE_SIZE;
 219                 region = region->next;
 220         }
 221
 222         return 0;
 223 }
 224
 225 __initcall(setup_iomem);