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);
99