rom/kernel/kernel_mm.c

   1 /*
   2     Copyright © 2010-2017, 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_intern.h>
  19 #include <kernel_debug.h>
  20 #include <kernel_mm.h>
  21
  22 #define D(x)
  23
  24 void *mm_AllocPages(void *addr, uintptr_t length, uint32_t flags, struct KernelBase *KernelBase)
  25 {
  26     APTR res = NULL;
  27     struct MemHeader *mh;
  28     ULONG physFlags = flags & MEMF_PHYSICAL_MASK;
  29
  30     /*
  31      * Loop over MemHeader structures.
  32      * We only add MemHeaders and never remove them, so i hope Forbid()/Permit()
  33      * is not really necessary here.
  34      */
  35     ForeachNode(&SysBase->MemList, mh)
  36     {
  37         /*
  38          * Check for the right requirements and enough free memory.
  39          * The requirements are OK if there's no bit in the
  40          * 'physFlags' that isn't set in the 'mh->mh_Attributes'.
  41          */
  42         if ((physFlags & ~mh->mh_Attributes) || mh->mh_Free < length)
  43            continue;
  44
  45         if (addr)
  46         {
  47             /*
  48              * If we have starting address, only one MemHeader can be
  49              * appropriate for us. We look for it and attempt to allocate
  50              * the given region from it.
  51              */
  52             if (addr >= mh->mh_Lower || addr + length <= mh->mh_Upper)
  53             {
  54                 res = mm_AllocAbs(mh, addr, length);
  55                 break;
  56             }
  57         }
  58         else
  59         {
  60             /*
  61              * Otherwise try to allocate pages from every MemHeader.
  62              * Note that we still may fail if the memory is fragmented too much.
  63              */
  64             res = mm_Allocate(mh, length, flags);
  65             if (res)
  66                 break;
  67         }
  68     }
  69
  70     return res;
  71 }
  72
  73 void mm_FreePages(void *addr, uintptr_t length, struct KernelBase *KernelBase)
  74 {
  75     struct MemHeader *mh;
  76
  77     ForeachNode(&SysBase->MemList, mh)
  78     {
  79         D(bug("[KrnFreePages] Checking MemHeader 0x%p... ", mh));
  80
  81         /* Test if the memory belongs to this MemHeader. */
  82         if (mh->mh_Lower <= addr && mh->mh_Upper > addr)
  83         {
  84             D(bug("[KrnFreePages] Match!\n"));
  85
  86             /* Test if it really fits into this MemHeader. */
  87             if ((addr + length) > mh->mh_Upper)
  88                 /* Something is completely wrong. */
  89                 Alert(AN_MemCorrupt|AT_DeadEnd);
  90
  91             mm_Free(mh, addr, length);
  92             break;
  93         }
  94
  95         D(bug("[KrnFreePages] No match!\n"));
  96     }
  97 }
  98
  99 /* Allocate a space usable by exec.library/Allocate() inside kernel's MemHeader. */
 100 struct MemHeader *mm_AllocExecHeader(struct MemHeader *mh, STRPTR name, IPTR maxsize)
 101 {
 102     struct MemHeader *bootmh = mm_Allocate(mh, maxsize, MEMF_ANY);
 103
 104     if (bootmh)
 105     {
 106         bootmh->mh_Node.ln_Succ    = NULL;
 107         bootmh->mh_Node.ln_Pred    = NULL;
 108         bootmh->mh_Node.ln_Name    = name;
 109         bootmh->mh_Node.ln_Type    = mh->mh_Node.ln_Type;
 110         bootmh->mh_Node.ln_Pri     = mh->mh_Node.ln_Pri;
 111         bootmh->mh_Attributes      = mh->mh_Attributes;
 112         bootmh->mh_First           = (APTR)((IPTR)bootmh + MEMHEADER_TOTAL);
 113         bootmh->mh_First->mc_Next  = NULL;
 114         bootmh->mh_First->mc_Bytes = maxsize - MEMHEADER_TOTAL;
 115
 116         /*
 117          * mh_Lower and mh_Upper are informational only. Since our MemHeader resides
 118          * inside the region it describes, the region includes MemHeader.
 119          */
 120         bootmh->mh_Lower           = (APTR)((IPTR)bootmh);
 121         bootmh->mh_Upper           = (APTR)((IPTR)bootmh + maxsize);
 122         bootmh->mh_Free            = bootmh->mh_First->mc_Bytes;
 123     }
 124
 125     return bootmh;
 126 }