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