rom/kernel/kernel_mm.c

   1 /*
   2     Copyright © 2010-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Page-based memory allocator, low-level routines.
   6     Lang: english
   7 */
   8
   9 #include <aros/config.h>
  10 #include <exec/alerts.h>
  11 #include <exec/execbase.h>
  12 #include <proto/arossupport.h>
  13 #include <proto/exec.h>
  14
  15 #include <inttypes.h>
  16
  17 #include <kernel_base.h>
  18 #include <kernel_debug.h>
  19 #include <kernel_mm.h>
  20
  21 #define D(x)
  22
  23 void *mm_AllocPages(void *addr, uintptr_t length, uint32_t flags, struct KernelBase *KernelBase)
  24 {
  25     APTR res = NULL;
  26     struct MemHeader *mh;
  27     ULONG physFlags = flags & MEMF_PHYSICAL_MASK;
  28
  29     /*
  30      * Loop over MemHeader structures.
  31      * We only add MemHeaders and never remove them, so i hope Forbid()/Permit()
  32      * is not really necessary here.
  33      */
  34     ForeachNode(&SysBase->MemList, mh)
  35     {
  36         /*
  37          * Check for the right requirements and enough free memory.
  38          * The requirements are OK if there's no bit in the
  39          * 'physFlags' that isn't set in the 'mh->mh_Attributes'.
  40          */
  41         if ((physFlags & ~mh->mh_Attributes) || mh->mh_Free < length)
  42            continue;
  43
  44         if (addr)
  45         {
  46             /*
  47              * If we have starting address, only one MemHeader can be
  48              * appropriate for us. We look for it and attempt to allocate
  49              * the given region from it.
  50              */
  51             if (addr >= mh->mh_Lower || addr + length <= mh->mh_Upper)
  52             {
  53                 res = mm_AllocAbs(mh, addr, length);
  54                 break;
  55             }
  56         }
  57         else
  58         {
  59             /*
  60              * Otherwise try to allocate pages from every MemHeader.
  61              * Note that we still may fail if the memory is fragmented too much.
  62              */
  63             res = mm_Allocate(mh, length, flags);
  64             if (res)
  65                 break;
  66         }
  67     }
  68
  69     return res;
  70 }
  71
  72 void mm_FreePages(void *addr, uintptr_t length, struct KernelBase *KernelBase)
  73 {
  74     struct MemHeader *mh;
  75
  76     ForeachNode(&SysBase->MemList, mh)
  77     {
  78         D(bug("[KrnFreePages] Checking MemHeader 0x%p... ", mh));
  79
  80         /* Test if the memory belongs to this MemHeader. */
  81         if (mh->mh_Lower <= addr && mh->mh_Upper > addr)
  82         {
  83             D(bug("[KrnFreePages] Match!\n"));
  84
  85             /* Test if it really fits into this MemHeader. */
  86             if ((addr + length) > mh->mh_Upper)
  87                 /* Something is completely wrong. */
  88                 Alert(AN_MemCorrupt|AT_DeadEnd);
  89
  90             mm_Free(mh, addr, length);
  91             break;
  92         }
  93
  94         D(bug("[KrnFreePages] No match!\n"));
  95     }
  96 }
  97
  98 /* Allocate a space usable by exec.library/Allocate() inside kernel's MemHeader. */
  99 struct MemHeader *mm_AllocExecHeader(struct MemHeader *mh, STRPTR name, IPTR maxsize)
 100 {
 101     struct MemHeader *bootmh = mm_Allocate(mh, maxsize, MEMF_ANY);
 102
 103     if (bootmh)
 104     {
 105         bootmh->mh_Node.ln_Succ    = NULL;
 106         bootmh->mh_Node.ln_Pred    = NULL;
 107         bootmh->mh_Node.ln_Name    = name;
 108         bootmh->mh_Node.ln_Type    = mh->mh_Node.ln_Type;
 109         bootmh->mh_Node.ln_Pri     = mh->mh_Node.ln_Pri;
 110         bootmh->mh_Attributes      = mh->mh_Attributes;
 111         bootmh->mh_First           = (APTR)((IPTR)bootmh + MEMHEADER_TOTAL);
 112         bootmh->mh_First->mc_Next  = NULL;
 113         bootmh->mh_First->mc_Bytes = maxsize - MEMHEADER_TOTAL;
 114
 115         /*
 116          * mh_Lower and mh_Upper are informational only. Since our MemHeader resides
 117          * inside the region it describes, the region includes MemHeader.
 118          */
 119         bootmh->mh_Lower           = (APTR)((IPTR)bootmh);
 120         bootmh->mh_Upper           = (APTR)((IPTR)bootmh + maxsize);
 121         bootmh->mh_Free            = bootmh->mh_First->mc_Bytes;
 122     }
 123
 124     return bootmh;
 125 }