rom/kernel/allocpages.c

   1 /*
   2     Copyright © 1995-2013, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6 */
   7
   8 #include <aros/config.h>
   9
  10 #include <kernel_base.h>
  11 #include <kernel_mm.h>
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <proto/kernel.h>
  17
  18         AROS_LH3(void *, KrnAllocPages,
  19
  20 /*  SYNOPSIS */
  21         AROS_LHA(void *, addr, A0),
  22         AROS_LHA(uintptr_t, length, D0),
  23         AROS_LHA(uint32_t, flags, D1),
  24
  25 /*  LOCATION */
  26         struct KernelBase *, KernelBase, 27, Kernel)
  27
  28 /*  FUNCTION
  29         Allocate physical memory pages
  30
  31     INPUTS
  32         addr   - Starting address of region which must be included in the
  33                  allocated region or NULL for the system to choose the
  34                  starting address. Normally you will supply NULL here.
  35         length - Length of the memory region to allocate
  36         flags  - Flags describing type of needed memory. These are the same
  37                  flags as passed to exec.library/AllocMem().
  38
  39     RESULT
  40         Real starting address of the allocated region.
  41
  42     NOTES
  43         Since this allocator is page-based, length will always be round up
  44         to system's memory page size. The same applies to starting address
  45         (if specified), it will be rounded down to page boundary.
  46
  47         This function works only on systems with MMU support. Without MMU
  48         it will always return NULL.
  49
  50     EXAMPLE
  51
  52     BUGS
  53
  54     SEE ALSO
  55         KrnFreePages()
  56
  57     INTERNALS
  58
  59 ******************************************************************************/
  60 {
  61     AROS_LIBFUNC_INIT
  62
  63     APTR res = NULL;
  64 #if USE_MMU
  65     KRN_MapAttr protection;
  66
  67     /* We can't work if MMU is not up */
  68     if (!KernelBase->kb_PageSize)
  69         return NULL;
  70
  71     /* Get permissions */
  72     protection = MAP_Readable|MAP_Writable;
  73     if (flags & MEMF_EXECUTABLE)
  74         protection |= MAP_Executable;
  75
  76     res = mm_AllocPages(addr, length, flags, KernelBase);
  77
  78     /*
  79      * The pages we've just allocated have no access rights at all.
  80      * Now we need to set requested access rights.
  81      */
  82     if (res)
  83         KrnSetProtection(res, length, protection);
  84 #endif
  85
  86     return res;
  87
  88     AROS_LIBFUNC_EXIT
  89 }