1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
/*
* Heap Handler
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/score/sysstate.h>
#include <rtems/score/heap.h>
#if defined(RTEMS_HEAP_DEBUG)
static void
check_result(
Heap_Control* the_heap,
Heap_Block* the_block,
_H_uptr_t user_addr,
_H_uptr_t aligned_user_addr,
uint32_t size)
{
_H_uptr_t const user_area = _H_p2u(_Heap_User_area(the_block));
_H_uptr_t const block_end = _H_p2u(the_block)
+ _Heap_Block_size(the_block) + HEAP_BLOCK_HEADER_OFFSET;
_H_uptr_t const user_end = aligned_user_addr + size;
_H_uptr_t const heap_start = _H_p2u(the_heap->start) + HEAP_OVERHEAD;
_H_uptr_t const heap_end = _H_p2u(the_heap->final)
+ HEAP_BLOCK_HEADER_OFFSET;
uint32_t const page_size = the_heap->page_size;
_HAssert(user_addr == user_area);
_HAssert(aligned_user_addr - user_area < page_size);
_HAssert(aligned_user_addr >= user_area);
_HAssert(aligned_user_addr < block_end);
_HAssert(user_end > user_area);
_HAssert(user_end <= block_end);
_HAssert(aligned_user_addr >= heap_start);
_HAssert(aligned_user_addr < heap_end);
_HAssert(user_end > heap_start);
_HAssert(user_end <= heap_end);
}
#else /* !defined(RTEMS_HEAP_DEBUG) */
#define check_result(a, b, c, d, e) ((void)0)
#endif /* !defined(RTEMS_HEAP_DEBUG) */
/*PAGE
*
* _Heap_Allocate_aligned
*
* This kernel routine allocates the requested size of memory
* from the specified heap so that returned address is aligned according to
* the 'alignment'.
*
* Input parameters:
* the_heap - pointer to the heap control block.
* size - size in bytes of the memory block to allocate.
* alignment - required user pointer alignment in bytes
*
* Output parameters:
* returns - starting address of memory block allocated. The address is
* aligned on specified boundary.
*/
void *_Heap_Allocate_aligned(
Heap_Control *the_heap,
size_t size,
uint32_t alignment
)
{
uint32_t search_count;
Heap_Block *the_block;
void *user_ptr = NULL;
uint32_t const page_size = the_heap->page_size;
Heap_Statistics *const stats = &the_heap->stats;
Heap_Block *const tail = _Heap_Tail(the_heap);
uint32_t const end_to_user_offs = size - HEAP_BLOCK_HEADER_OFFSET;
uint32_t const the_size =
_Heap_Calc_block_size(size, page_size, the_heap->min_block_size);
if(the_size == 0)
return NULL;
if(alignment == 0)
alignment = CPU_ALIGNMENT;
/* Find large enough free block that satisfies the alignment requirements. */
for(the_block = _Heap_Head(the_heap)->next, search_count = 0;
the_block != tail;
the_block = the_block->next, ++search_count)
{
uint32_t const block_size = _Heap_Block_size(the_block);
/* As we always coalesce free blocks, prev block must have been used. */
_HAssert(_Heap_Is_prev_used(the_block));
if(block_size >= the_size) { /* the_block is large enough. */
_H_uptr_t user_addr;
_H_uptr_t aligned_user_addr;
_H_uptr_t const user_area = _H_p2u(_Heap_User_area(the_block));
/* Calculate 'aligned_user_addr' that will become the user pointer we
return. It should be at least 'end_to_user_offs' bytes less than the
the 'block_end' and should be aligned on 'alignment' boundary.
Calculations are from the 'block_end' as we are going to split free
block so that the upper part of the block becomes used block. */
_H_uptr_t const block_end = _H_p2u(the_block) + block_size;
aligned_user_addr = block_end - end_to_user_offs;
_Heap_Align_down_uptr(&aligned_user_addr, alignment);
/* 'user_addr' is the 'aligned_user_addr' further aligned down to the
'page_size' boundary. We need it as blocks' user areas should begin
only at 'page_size' aligned addresses */
user_addr = aligned_user_addr;
_Heap_Align_down_uptr(&user_addr, page_size);
/* Make sure 'user_addr' calculated didn't run out of 'the_block. */
if(user_addr >= user_area) {
/* The block seems to be acceptable. Check if the remainder of
'the_block' is less than 'min_block_size' so that 'the_block' won't
actually be split at the address we assume. */
if(user_addr - user_area < the_heap->min_block_size) {
/* The block won't be split, so 'user_addr' will be equal to the
'user_area'. */
user_addr = user_area;
/* We can't allow the distance between 'user_addr' and
'aligned_user_addr' to be outside of [0,page_size) range. If we do,
we will need to store this distance somewhere to be able to
resurrect the block address from the user pointer. (Having the
distance within [0,page_size) range allows resurrection by
aligning user pointer down to the nearest 'page_size' boundary.) */
if(aligned_user_addr - user_addr >= page_size) {
/* The user pointer will be too far from 'user_addr'. See if we
can make 'aligned_user_addr' to be close enough to the
'user_addr'. */
aligned_user_addr = user_addr;
_Heap_Align_up_uptr(&aligned_user_addr, alignment);
if(aligned_user_addr - user_addr >= page_size) {
/* No, we can't use the block */
aligned_user_addr = 0;
}
}
}
if(aligned_user_addr) {
/* The block is indeed acceptable: calculate the size of the block
to be allocated and perform allocation. */
uint32_t const alloc_size =
block_end - user_addr + HEAP_BLOCK_USER_OFFSET;
_HAssert(_Heap_Is_aligned_ptr((void*)aligned_user_addr, alignment));
(void)_Heap_Block_allocate(the_heap, the_block, alloc_size);
stats->searches += search_count + 1;
stats->allocs += 1;
check_result(the_heap, the_block, user_addr,
aligned_user_addr, size);
user_ptr = (void*)aligned_user_addr;
break;
}
}
}
}
if(stats->max_search < search_count)
stats->max_search = search_count;
return user_ptr;
}
|
