rom/kernel/allocpages.c

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