core/mem/malloc.h

   1 /*
   2  * malloc.h
   3  *
   4  * Internals for the memory allocator
   5  */
   6
   7 #include <stdint.h>
   8 #include <stddef.h>
   9 #include "core.h"
  10
  11 /*
  12  * This is a temporary hack.  In Syslinux 5 this will be a pointer to
  13  * the owner module.
  14  */
  15 typedef size_t malloc_tag_t;
  16 enum malloc_owner {
  17     MALLOC_FREE,
  18     MALLOC_HEAD,
  19     MALLOC_CORE,
  20     MALLOC_MODULE,
  21 };
  22
  23 struct free_arena_header;
  24
  25 /*
  26  * This structure should be a power of two.  This becomes the
  27  * alignment unit.
  28  */
  29 struct arena_header {
  30     malloc_tag_t tag;
  31     size_t attrs;                       /* Bits 0..1:  Type
  32                                                 2..3:  Heap,
  33                                                 4..31: MSB of the size  */
  34     struct free_arena_header *next, *prev;
  35 };
  36
  37 enum arena_type {
  38     ARENA_TYPE_USED = 0,
  39     ARENA_TYPE_FREE = 1,
  40     ARENA_TYPE_HEAD = 2,
  41     ARENA_TYPE_DEAD = 3,
  42 };
  43 enum heap {
  44     HEAP_MAIN,
  45     HEAP_LOWMEM,
  46     NHEAP
  47 };
  48
  49 #define ARENA_SIZE_MASK (~(uintptr_t)(sizeof(struct arena_header)-1))
  50 #define ARENA_HEAP_MASK ((size_t)0xc)
  51 #define ARENA_HEAP_POS  2
  52 #define ARENA_TYPE_MASK ((size_t)0x3)
  53
  54 #define ARENA_ALIGN_UP(p)       ((char *)(((uintptr_t)(p) + ~ARENA_SIZE_MASK) \
  55                                           & ARENA_SIZE_MASK))
  56 #define ARENA_ALIGN_DOWN(p)     ((char *)((uintptr_t)(p) & ARENA_SIZE_MASK))
  57
  58 #define ARENA_SIZE_GET(attrs)   ((attrs) & ARENA_SIZE_MASK)
  59 #define ARENA_HEAP_GET(attrs)   (((attrs) & ARENA_HEAP_MASK) >> ARENA_HEAP_POS)
  60 #define ARENA_TYPE_GET(attrs)   ((attrs) & ARENA_TYPE_MASK)
  61
  62 #define ARENA_SIZE_SET(attrs, size)     \
  63         ((attrs) = ((size) & ARENA_SIZE_MASK) | ((attrs) & ~ARENA_SIZE_MASK))
  64 #define ARENA_HEAP_SET(attrs, heap)     \
  65         ((attrs) = (((heap) << ARENA_HEAP_POS) & ARENA_HEAP_MASK) | \
  66          ((attrs) & ~ARENA_HEAP_MASK))
  67 #define ARENA_TYPE_SET(attrs, type) \
  68         ((attrs) = ((attrs) & ~ARENA_TYPE_MASK) | \
  69          ((type) & ARENA_TYPE_MASK))
  70
  71 /*
  72  * This structure should be no more than twice the size of the
  73  * previous structure.
  74  */
  75 struct free_arena_header {
  76     struct arena_header a;
  77     struct free_arena_header *next_free, *prev_free;
  78     size_t _pad[2];             /* Pad to 2*sizeof(struct arena_header) */
  79 };
  80
  81 extern struct free_arena_header __malloc_head[NHEAP];
  82 void __inject_free_block(struct free_arena_header *ah);