arch/um/include/asm/fixmap.h

   1 #ifndef __UM_FIXMAP_H
   2 #define __UM_FIXMAP_H
   3
   4 #include <asm/processor.h>
   5 #include <asm/kmap_types.h>
   6 #include <asm/archparam.h>
   7 #include <asm/page.h>
   8 #include <linux/threads.h>
   9
  10 /*
  11  * Here we define all the compile-time 'special' virtual
  12  * addresses. The point is to have a constant address at
  13  * compile time, but to set the physical address only
  14  * in the boot process. We allocate these special  addresses
  15  * from the end of virtual memory (0xfffff000) backwards.
  16  * Also this lets us do fail-safe vmalloc(), we
  17  * can guarantee that these special addresses and
  18  * vmalloc()-ed addresses never overlap.
  19  *
  20  * these 'compile-time allocated' memory buffers are
  21  * fixed-size 4k pages. (or larger if used with an increment
  22  * highger than 1) use fixmap_set(idx,phys) to associate
  23  * physical memory with fixmap indices.
  24  *
  25  * TLB entries of such buffers will not be flushed across
  26  * task switches.
  27  */
  28
  29 /*
  30  * on UP currently we will have no trace of the fixmap mechanizm,
  31  * no page table allocations, etc. This might change in the
  32  * future, say framebuffers for the console driver(s) could be
  33  * fix-mapped?
  34  */
  35 enum fixed_addresses {
  36         __end_of_fixed_addresses
  37 };
  38
  39 extern void __set_fixmap (enum fixed_addresses idx,
  40                           unsigned long phys, pgprot_t flags);
  41
  42 /*
  43  * used by vmalloc.c.
  44  *
  45  * Leave one empty page between vmalloc'ed areas and
  46  * the start of the fixmap, and leave one page empty
  47  * at the top of mem..
  48  */
  49
  50 #define FIXADDR_TOP     (TASK_SIZE - 2 * PAGE_SIZE)
  51 #define FIXADDR_SIZE    (__end_of_fixed_addresses << PAGE_SHIFT)
  52 #define FIXADDR_START   (FIXADDR_TOP - FIXADDR_SIZE)
  53
  54 #include <asm-generic/fixmap.h>
  55
  56 #endif