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physmem.c

/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include "linux/bootmem.h"
#include "linux/mm.h"
#include "linux/pfn.h"
#include "asm/page.h"
#include "as-layout.h"
#include "init.h"
#include "kern.h"
#include "mem_user.h"
#include "os.h"

static int physmem_fd = -1;

/* Changed during early boot */
unsigned long high_physmem;

extern unsigned long long physmem_size;

int __init init_maps(unsigned long physmem, unsigned long iomem,
                 unsigned long highmem)
{
      struct page *p, *map;
      unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
      unsigned long iomem_len, iomem_pages, total_len, total_pages;
      int i;

      phys_pages = physmem >> PAGE_SHIFT;
      phys_len = phys_pages * sizeof(struct page);

      iomem_pages = iomem >> PAGE_SHIFT;
      iomem_len = iomem_pages * sizeof(struct page);

      highmem_pages = highmem >> PAGE_SHIFT;
      highmem_len = highmem_pages * sizeof(struct page);

      total_pages = phys_pages + iomem_pages + highmem_pages;
      total_len = phys_len + iomem_len + highmem_len;

      map = alloc_bootmem_low_pages(total_len);
      if (map == NULL)
            return -ENOMEM;

      for (i = 0; i < total_pages; i++) {
            p = &map[i];
            memset(p, 0, sizeof(struct page));
            SetPageReserved(p);
            INIT_LIST_HEAD(&p->lru);
      }

      max_mapnr = total_pages;
      return 0;
}

/* Changed during early boot */
static unsigned long kmem_top = 0;

unsigned long get_kmem_end(void)
{
      if (kmem_top == 0)
            kmem_top = host_task_size - 1024 * 1024;
      return kmem_top;
}

void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
            int r, int w, int x)
{
      __u64 offset;
      int fd, err;

      fd = phys_mapping(phys, &offset);
      err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
      if (err) {
            if (err == -ENOMEM)
                  printk(KERN_ERR "try increasing the host's "
                         "/proc/sys/vm/max_map_count to <physical "
                         "memory size>/4096\n");
            panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
                  "err = %d\n", virt, fd, offset, len, r, w, x, err);
      }
}

extern int __syscall_stub_start;

void __init setup_physmem(unsigned long start, unsigned long reserve_end,
                    unsigned long len, unsigned long long highmem)
{
      unsigned long reserve = reserve_end - start;
      int pfn = PFN_UP(__pa(reserve_end));
      int delta = (len - reserve) >> PAGE_SHIFT;
      int err, offset, bootmap_size;

      physmem_fd = create_mem_file(len + highmem);

      offset = uml_reserved - uml_physmem;
      err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
                      len - offset, 1, 1, 1);
      if (err < 0) {
            printf("setup_physmem - mapping %ld bytes of memory at 0x%p "
                   "failed - errno = %d\n", len - offset,
                   (void *) uml_reserved, err);
            exit(1);
      }

      /*
       * Special kludge - This page will be mapped in to userspace processes
       * from physmem_fd, so it needs to be written out there.
       */
      os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
      os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);

      bootmap_size = init_bootmem(pfn, pfn + delta);
      free_bootmem(__pa(reserve_end) + bootmap_size,
                 len - bootmap_size - reserve);
}

int phys_mapping(unsigned long phys, unsigned long long *offset_out)
{
      int fd = -1;

      if (phys < physmem_size) {
            fd = physmem_fd;
            *offset_out = phys;
      }
      else if (phys < __pa(end_iomem)) {
            struct iomem_region *region = iomem_regions;

            while (region != NULL) {
                  if ((phys >= region->phys) &&
                      (phys < region->phys + region->size)) {
                        fd = region->fd;
                        *offset_out = phys - region->phys;
                        break;
                  }
                  region = region->next;
            }
      }
      else if (phys < __pa(end_iomem) + highmem) {
            fd = physmem_fd;
            *offset_out = phys - iomem_size;
      }

      return fd;
}

static int __init uml_mem_setup(char *line, int *add)
{
      char *retptr;
      physmem_size = memparse(line,&retptr);
      return 0;
}
__uml_setup("mem=", uml_mem_setup,
"mem=<Amount of desired ram>\n"
"    This controls how much \"physical\" memory the kernel allocates\n"
"    for the system. The size is specified as a number followed by\n"
"    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
"    This is not related to the amount of memory in the host.  It can\n"
"    be more, and the excess, if it's ever used, will just be swapped out.\n"
"     Example: mem=64M\n\n"
);

extern int __init parse_iomem(char *str, int *add);

__uml_setup("iomem=", parse_iomem,
"iomem=<name>,<file>\n"
"    Configure <file> as an IO memory region named <name>.\n\n"
);

/*
 * This list is constructed in parse_iomem and addresses filled in in
 * setup_iomem, both of which run during early boot.  Afterwards, it's
 * unchanged.
 */
struct iomem_region *iomem_regions = NULL;

/* Initialized in parse_iomem */
int iomem_size = 0;

unsigned long find_iomem(char *driver, unsigned long *len_out)
{
      struct iomem_region *region = iomem_regions;

      while (region != NULL) {
            if (!strcmp(region->driver, driver)) {
                  *len_out = region->size;
                  return region->virt;
            }

            region = region->next;
      }

      return 0;
}

int setup_iomem(void)
{
      struct iomem_region *region = iomem_regions;
      unsigned long iomem_start = high_physmem + PAGE_SIZE;
      int err;

      while (region != NULL) {
            err = os_map_memory((void *) iomem_start, region->fd, 0,
                            region->size, 1, 1, 0);
            if (err)
                  printk(KERN_ERR "Mapping iomem region for driver '%s' "
                         "failed, errno = %d\n", region->driver, -err);
            else {
                  region->virt = iomem_start;
                  region->phys = __pa(region->virt);
            }

            iomem_start += region->size + PAGE_SIZE;
            region = region->next;
      }

      return 0;
}

__initcall(setup_iomem);

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