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 #include "thread.h"
  11
  12 extern struct semaphore __malloc_semaphore;
  13
  14 /*
  15  * This is a temporary hack.  In Syslinux 5 this will be a pointer to
  16  * the owner module.
  17  */
  18 typedef size_t malloc_tag_t;
  19 enum malloc_owner {
  20     MALLOC_FREE,
  21     MALLOC_HEAD,
  22     MALLOC_CORE,
  23     MALLOC_MODULE,
  24 };
  25
  26 enum arena_type {
  27     ARENA_TYPE_USED = 0,
  28     ARENA_TYPE_FREE = 1,
  29     ARENA_TYPE_HEAD = 2,
  30     ARENA_TYPE_DEAD = 3,
  31 };
  32 enum heap {
  33     HEAP_MAIN,
  34     HEAP_LOWMEM,
  35     NHEAP
  36 };
  37
  38 #define ARENA_MAGIC 0x20130117
  39
  40 struct free_arena_header;
  41
  42 /*
  43  * This structure should be a power of two.  This becomes the
  44  * alignment unit.
  45  */
  46 struct arena_header {
  47     malloc_tag_t tag;
  48     size_t attrs;                       /* Bits 0..1:  Type
  49                                                 2..3:  Heap,
  50                                                 4..31: MSB of the size  */
  51     struct free_arena_header *next, *prev;
  52
  53 #ifdef DEBUG_MALLOC
  54     unsigned long _pad[3];
  55     unsigned int magic;
  56 #endif
  57 };
  58
  59 /* Pad to 2*sizeof(struct arena_header) */
  60 #define ARENA_PADDING ((2 * sizeof(struct arena_header)) - \
  61                        (sizeof(struct arena_header) + \
  62                         sizeof(struct free_arena_header *) +    \
  63                         sizeof(struct free_arena_header *)))
  64
  65 /*
  66  * This structure should be no more than twice the size of the
  67  * previous structure.
  68  */
  69 struct free_arena_header {
  70     struct arena_header a;
  71     struct free_arena_header *next_free, *prev_free;
  72     size_t _pad[ARENA_PADDING];
  73 };
  74
  75 #define ARENA_SIZE_MASK (~(uintptr_t)(sizeof(struct arena_header)-1))
  76 #define ARENA_HEAP_MASK ((size_t)0xc)
  77 #define ARENA_HEAP_POS  2
  78 #define ARENA_TYPE_MASK ((size_t)0x3)
  79
  80 #define ARENA_ALIGN_UP(p)       ((char *)(((uintptr_t)(p) + ~ARENA_SIZE_MASK) \
  81                                           & ARENA_SIZE_MASK))
  82 #define ARENA_ALIGN_DOWN(p)     ((char *)((uintptr_t)(p) & ARENA_SIZE_MASK))
  83
  84 #define ARENA_SIZE_GET(attrs)   ((attrs) & ARENA_SIZE_MASK)
  85 #define ARENA_HEAP_GET(attrs)   (((attrs) & ARENA_HEAP_MASK) >> ARENA_HEAP_POS)
  86 #define ARENA_TYPE_GET(attrs)   ((attrs) & ARENA_TYPE_MASK)
  87
  88 #define ARENA_SIZE_SET(attrs, size)     \
  89         ((attrs) = ((size) & ARENA_SIZE_MASK) | ((attrs) & ~ARENA_SIZE_MASK))
  90 #define ARENA_HEAP_SET(attrs, heap)     \
  91         ((attrs) = (((heap) << ARENA_HEAP_POS) & ARENA_HEAP_MASK) | \
  92          ((attrs) & ~ARENA_HEAP_MASK))
  93 #define ARENA_TYPE_SET(attrs, type) \
  94         ((attrs) = ((attrs) & ~ARENA_TYPE_MASK) | \
  95          ((type) & ARENA_TYPE_MASK))
  96
  97 extern struct free_arena_header __core_malloc_head[NHEAP];
  98 void __inject_free_block(struct free_arena_header *ah);