1 | /* |
---|
2 | * Heap Handler |
---|
3 | * |
---|
4 | * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. |
---|
5 | * On-Line Applications Research Corporation (OAR). |
---|
6 | * All rights assigned to U.S. Government, 1994. |
---|
7 | * |
---|
8 | * This material may be reproduced by or for the U.S. Government pursuant |
---|
9 | * to the copyright license under the clause at DFARS 252.227-7013. This |
---|
10 | * notice must appear in all copies of this file and its derivatives. |
---|
11 | * |
---|
12 | * $Id$ |
---|
13 | */ |
---|
14 | |
---|
15 | |
---|
16 | #include <rtems/system.h> |
---|
17 | #include <rtems/core/heap.h> |
---|
18 | #include <rtems/sysstate.h> |
---|
19 | |
---|
20 | /*PAGE |
---|
21 | * |
---|
22 | * _Heap_Initialize |
---|
23 | * |
---|
24 | * This kernel routine initializes a heap. |
---|
25 | * |
---|
26 | * Input parameters: |
---|
27 | * the_heap - pointer to heap header |
---|
28 | * starting_address - starting address of heap |
---|
29 | * size - size of heap |
---|
30 | * page_size - allocatable unit of memory |
---|
31 | * |
---|
32 | * Output parameters: |
---|
33 | * returns - maximum memory available if successfully initialized |
---|
34 | * 0 - otherwise |
---|
35 | * |
---|
36 | * This is what a heap looks like in memory immediately |
---|
37 | * after initialization: |
---|
38 | * |
---|
39 | * +--------------------------------+ |
---|
40 | * 0 | size = 0 | status = used | a.k.a. dummy back flag |
---|
41 | * +--------------------------------+ |
---|
42 | * 4 | size = size-8 | status = free | a.k.a. front flag |
---|
43 | * +--------------------------------+ |
---|
44 | * 8 | next = PERM HEAP_TAIL | |
---|
45 | * +--------------------------------+ |
---|
46 | * 12 | previous = PERM HEAP_HEAD | |
---|
47 | * +--------------------------------+ |
---|
48 | * | | |
---|
49 | * | memory available | |
---|
50 | * | for allocation | |
---|
51 | * | | |
---|
52 | * +--------------------------------+ |
---|
53 | * size - 8 | size = size-8 | status = free | a.k.a. back flag |
---|
54 | * +--------------------------------+ |
---|
55 | * size - 4 | size = 0 | status = used | a.k.a. dummy front flag |
---|
56 | * +--------------------------------+ |
---|
57 | */ |
---|
58 | |
---|
59 | unsigned32 _Heap_Initialize( |
---|
60 | Heap_Control *the_heap, |
---|
61 | void *starting_address, |
---|
62 | unsigned32 size, |
---|
63 | unsigned32 page_size |
---|
64 | ) |
---|
65 | { |
---|
66 | Heap_Block *the_block; |
---|
67 | unsigned32 the_size; |
---|
68 | |
---|
69 | if ( !_Heap_Is_page_size_valid( page_size ) || |
---|
70 | (size < HEAP_MINIMUM_SIZE) ) |
---|
71 | return 0; |
---|
72 | |
---|
73 | the_heap->page_size = page_size; |
---|
74 | the_size = size - HEAP_OVERHEAD; |
---|
75 | |
---|
76 | the_block = (Heap_Block *) starting_address; |
---|
77 | the_block->back_flag = HEAP_DUMMY_FLAG; |
---|
78 | the_block->front_flag = the_size; |
---|
79 | the_block->next = _Heap_Tail( the_heap ); |
---|
80 | the_block->previous = _Heap_Head( the_heap ); |
---|
81 | |
---|
82 | the_heap->start = the_block; |
---|
83 | the_heap->first = the_block; |
---|
84 | the_heap->permanent_null = NULL; |
---|
85 | the_heap->last = the_block; |
---|
86 | |
---|
87 | the_block = _Heap_Next_block( the_block ); |
---|
88 | the_block->back_flag = the_size; |
---|
89 | the_block->front_flag = HEAP_DUMMY_FLAG; |
---|
90 | the_heap->final = the_block; |
---|
91 | |
---|
92 | return ( the_size - HEAP_BLOCK_USED_OVERHEAD ); |
---|
93 | } |
---|
94 | |
---|
95 | /*PAGE |
---|
96 | * |
---|
97 | * _Heap_Extend |
---|
98 | * |
---|
99 | * This routine grows the_heap memory area using the size bytes which |
---|
100 | * begin at starting_address. |
---|
101 | * |
---|
102 | * Input parameters: |
---|
103 | * the_heap - pointer to heap header. |
---|
104 | * starting_address - pointer to the memory area. |
---|
105 | * size - size in bytes of the memory block to allocate. |
---|
106 | * |
---|
107 | * Output parameters: |
---|
108 | * *amount_extended - amount of memory added to the_heap |
---|
109 | */ |
---|
110 | |
---|
111 | Heap_Extend_status _Heap_Extend( |
---|
112 | Heap_Control *the_heap, |
---|
113 | void *starting_address, |
---|
114 | unsigned32 size, |
---|
115 | unsigned32 *amount_extended |
---|
116 | ) |
---|
117 | { |
---|
118 | Heap_Block *the_block; |
---|
119 | |
---|
120 | /* |
---|
121 | * The overhead was taken from the original heap memory. |
---|
122 | */ |
---|
123 | |
---|
124 | Heap_Block *old_final; |
---|
125 | Heap_Block *new_final; |
---|
126 | |
---|
127 | /* |
---|
128 | * There are five possibilities for the location of starting |
---|
129 | * address: |
---|
130 | * |
---|
131 | * 1. non-contiguous lower address (NOT SUPPORTED) |
---|
132 | * 2. contiguous lower address (NOT SUPPORTED) |
---|
133 | * 3. in the heap (ERROR) |
---|
134 | * 4. contiguous higher address (SUPPORTED) |
---|
135 | * 5. non-contiguous higher address (NOT SUPPORTED) |
---|
136 | * |
---|
137 | * As noted, this code only supports (4). |
---|
138 | */ |
---|
139 | |
---|
140 | if ( starting_address >= (void *) the_heap->start && /* case 3 */ |
---|
141 | starting_address <= (void *) the_heap->final |
---|
142 | ) |
---|
143 | return HEAP_EXTEND_ERROR; |
---|
144 | |
---|
145 | if ( starting_address < (void *) the_heap->start ) { /* cases 1 and 2 */ |
---|
146 | |
---|
147 | return HEAP_EXTEND_NOT_IMPLEMENTED; /* cases 1 and 2 */ |
---|
148 | |
---|
149 | } else { /* cases 4 and 5 */ |
---|
150 | |
---|
151 | the_block = (Heap_Block *) (starting_address - HEAP_OVERHEAD); |
---|
152 | if ( the_block != the_heap->final ) |
---|
153 | return HEAP_EXTEND_NOT_IMPLEMENTED; /* case 5 */ |
---|
154 | } |
---|
155 | |
---|
156 | /* |
---|
157 | * Currently only case 4 should make it to this point. |
---|
158 | * The basic trick is to make the extend area look like a used |
---|
159 | * block and free it. |
---|
160 | */ |
---|
161 | |
---|
162 | *amount_extended = size; |
---|
163 | |
---|
164 | old_final = the_heap->final; |
---|
165 | new_final = _Addresses_Add_offset( old_final, size ); |
---|
166 | /* SAME AS: _Addresses_Add_offset( starting_address, size-HEAP_OVERHEAD ); */ |
---|
167 | |
---|
168 | the_heap->final = new_final; |
---|
169 | |
---|
170 | old_final->front_flag = |
---|
171 | new_final->back_flag = _Heap_Build_flag( size, HEAP_BLOCK_USED ); |
---|
172 | new_final->front_flag = HEAP_DUMMY_FLAG; |
---|
173 | |
---|
174 | /* |
---|
175 | * Must pass in address of "user" area |
---|
176 | */ |
---|
177 | |
---|
178 | _Heap_Free( the_heap, &old_final->next ); |
---|
179 | |
---|
180 | return HEAP_EXTEND_SUCCESSFUL; |
---|
181 | } |
---|
182 | |
---|
183 | /*PAGE |
---|
184 | * |
---|
185 | * _Heap_Allocate |
---|
186 | * |
---|
187 | * This kernel routine allocates the requested size of memory |
---|
188 | * from the specified heap. |
---|
189 | * |
---|
190 | * Input parameters: |
---|
191 | * the_heap - pointer to heap header. |
---|
192 | * size - size in bytes of the memory block to allocate. |
---|
193 | * |
---|
194 | * Output parameters: |
---|
195 | * returns - starting address of memory block allocated |
---|
196 | */ |
---|
197 | |
---|
198 | void *_Heap_Allocate( |
---|
199 | Heap_Control *the_heap, |
---|
200 | unsigned32 size |
---|
201 | ) |
---|
202 | { |
---|
203 | unsigned32 excess; |
---|
204 | unsigned32 the_size; |
---|
205 | Heap_Block *the_block; |
---|
206 | Heap_Block *next_block; |
---|
207 | Heap_Block *temporary_block; |
---|
208 | |
---|
209 | excess = size % the_heap->page_size; |
---|
210 | the_size = size + HEAP_BLOCK_USED_OVERHEAD; |
---|
211 | |
---|
212 | if ( excess ) |
---|
213 | the_size += the_heap->page_size - excess; |
---|
214 | |
---|
215 | if ( the_size < sizeof( Heap_Block ) ) |
---|
216 | the_size = sizeof( Heap_Block ); |
---|
217 | |
---|
218 | for ( the_block = the_heap->first; |
---|
219 | ; |
---|
220 | the_block = the_block->next ) { |
---|
221 | if ( the_block == _Heap_Tail( the_heap ) ) |
---|
222 | return( NULL ); |
---|
223 | if ( the_block->front_flag >= the_size ) |
---|
224 | break; |
---|
225 | } |
---|
226 | |
---|
227 | if ( (the_block->front_flag - the_size) > |
---|
228 | (the_heap->page_size + HEAP_BLOCK_USED_OVERHEAD) ) { |
---|
229 | the_block->front_flag -= the_size; |
---|
230 | next_block = _Heap_Next_block( the_block ); |
---|
231 | next_block->back_flag = the_block->front_flag; |
---|
232 | |
---|
233 | temporary_block = _Heap_Block_at( next_block, the_size ); |
---|
234 | temporary_block->back_flag = |
---|
235 | next_block->front_flag = _Heap_Build_flag( the_size, |
---|
236 | HEAP_BLOCK_USED ); |
---|
237 | return( _Heap_Start_of_user_area( next_block ) ); |
---|
238 | } else { |
---|
239 | next_block = _Heap_Next_block( the_block ); |
---|
240 | next_block->back_flag = _Heap_Build_flag( the_block->front_flag, |
---|
241 | HEAP_BLOCK_USED ); |
---|
242 | the_block->front_flag = next_block->back_flag; |
---|
243 | the_block->next->previous = the_block->previous; |
---|
244 | the_block->previous->next = the_block->next; |
---|
245 | return( _Heap_Start_of_user_area( the_block ) ); |
---|
246 | } |
---|
247 | } |
---|
248 | |
---|
249 | /*PAGE |
---|
250 | * |
---|
251 | * _Heap_Size_of_user_area |
---|
252 | * |
---|
253 | * This kernel routine returns the size of the memory area |
---|
254 | * given heap block. |
---|
255 | * |
---|
256 | * Input parameters: |
---|
257 | * the_heap - pointer to heap header |
---|
258 | * starting_address - starting address of the memory block to free. |
---|
259 | * size - pointer to size of area |
---|
260 | * |
---|
261 | * Output parameters: |
---|
262 | * size - size of area filled in |
---|
263 | * TRUE - if starting_address is valid heap address |
---|
264 | * FALSE - if starting_address is invalid heap address |
---|
265 | */ |
---|
266 | |
---|
267 | boolean _Heap_Size_of_user_area( |
---|
268 | Heap_Control *the_heap, |
---|
269 | void *starting_address, |
---|
270 | unsigned32 *size |
---|
271 | ) |
---|
272 | { |
---|
273 | Heap_Block *the_block; |
---|
274 | Heap_Block *next_block; |
---|
275 | unsigned32 the_size; |
---|
276 | |
---|
277 | the_block = _Heap_Block_at( starting_address, - (sizeof( void * ) * 2) ); |
---|
278 | |
---|
279 | if ( !_Heap_Is_block_in( the_heap, the_block ) || |
---|
280 | _Heap_Is_block_free( the_block ) ) |
---|
281 | return( FALSE ); |
---|
282 | |
---|
283 | the_size = _Heap_Block_size( the_block ); |
---|
284 | next_block = _Heap_Block_at( the_block, the_size ); |
---|
285 | |
---|
286 | if ( !_Heap_Is_block_in( the_heap, next_block ) || |
---|
287 | (the_block->front_flag != next_block->back_flag) ) |
---|
288 | return( FALSE ); |
---|
289 | |
---|
290 | *size = the_size; |
---|
291 | return( TRUE ); |
---|
292 | } |
---|
293 | |
---|
294 | /*PAGE |
---|
295 | * |
---|
296 | * _Heap_Free |
---|
297 | * |
---|
298 | * This kernel routine returns the memory designated by the |
---|
299 | * given heap and given starting address to the memory pool. |
---|
300 | * |
---|
301 | * Input parameters: |
---|
302 | * the_heap - pointer to heap header |
---|
303 | * starting_address - starting address of the memory block to free. |
---|
304 | * |
---|
305 | * Output parameters: |
---|
306 | * TRUE - if starting_address is valid heap address |
---|
307 | * FALSE - if starting_address is invalid heap address |
---|
308 | */ |
---|
309 | |
---|
310 | boolean _Heap_Free( |
---|
311 | Heap_Control *the_heap, |
---|
312 | void *starting_address |
---|
313 | ) |
---|
314 | { |
---|
315 | Heap_Block *the_block; |
---|
316 | Heap_Block *next_block; |
---|
317 | Heap_Block *new_next_block; |
---|
318 | Heap_Block *previous_block; |
---|
319 | Heap_Block *temporary_block; |
---|
320 | unsigned32 the_size; |
---|
321 | |
---|
322 | the_block = _Heap_Block_at( starting_address, - (sizeof( void * ) * 2) ); |
---|
323 | |
---|
324 | if ( !_Heap_Is_block_in( the_heap, the_block ) || |
---|
325 | _Heap_Is_block_free( the_block ) ) { |
---|
326 | return( FALSE ); |
---|
327 | } |
---|
328 | |
---|
329 | the_size = _Heap_Block_size( the_block ); |
---|
330 | next_block = _Heap_Block_at( the_block, the_size ); |
---|
331 | |
---|
332 | if ( !_Heap_Is_block_in( the_heap, next_block ) || |
---|
333 | (the_block->front_flag != next_block->back_flag) ) { |
---|
334 | return( FALSE ); |
---|
335 | } |
---|
336 | |
---|
337 | if ( _Heap_Is_previous_block_free( the_block ) ) { |
---|
338 | previous_block = _Heap_Previous_block( the_block ); |
---|
339 | |
---|
340 | if ( !_Heap_Is_block_in( the_heap, previous_block ) ) { |
---|
341 | return( FALSE ); |
---|
342 | } |
---|
343 | |
---|
344 | if ( _Heap_Is_block_free( next_block ) ) { /* coalesce both */ |
---|
345 | previous_block->front_flag += next_block->front_flag + the_size; |
---|
346 | temporary_block = _Heap_Next_block( previous_block ); |
---|
347 | temporary_block->back_flag = previous_block->front_flag; |
---|
348 | next_block->next->previous = next_block->previous; |
---|
349 | next_block->previous->next = next_block->next; |
---|
350 | } |
---|
351 | else { /* coalesce prev */ |
---|
352 | previous_block->front_flag = |
---|
353 | next_block->back_flag = previous_block->front_flag + the_size; |
---|
354 | } |
---|
355 | } |
---|
356 | else if ( _Heap_Is_block_free( next_block ) ) { /* coalesce next */ |
---|
357 | the_block->front_flag = the_size + next_block->front_flag; |
---|
358 | new_next_block = _Heap_Next_block( the_block ); |
---|
359 | new_next_block->back_flag = the_block->front_flag; |
---|
360 | the_block->next = next_block->next; |
---|
361 | the_block->previous = next_block->previous; |
---|
362 | next_block->previous->next = the_block; |
---|
363 | next_block->next->previous = the_block; |
---|
364 | |
---|
365 | if (the_heap->first == next_block) |
---|
366 | the_heap->first = the_block; |
---|
367 | } |
---|
368 | else { /* no coalesce */ |
---|
369 | next_block->back_flag = |
---|
370 | the_block->front_flag = the_size; |
---|
371 | the_block->previous = _Heap_Head( the_heap ); |
---|
372 | the_block->next = the_heap->first; |
---|
373 | the_heap->first = the_block; |
---|
374 | the_block->next->previous = the_block; |
---|
375 | } |
---|
376 | |
---|
377 | return( TRUE ); |
---|
378 | } |
---|
379 | |
---|
380 | /*PAGE |
---|
381 | * |
---|
382 | * _Heap_Walk |
---|
383 | * |
---|
384 | * This kernel routine walks the heap and verifies its correctness. |
---|
385 | * |
---|
386 | * Input parameters: |
---|
387 | * the_heap - pointer to heap header |
---|
388 | * source - a numeric indicator of the invoker of this routine |
---|
389 | * do_dump - when TRUE print the information |
---|
390 | * |
---|
391 | * Output parameters: NONE |
---|
392 | */ |
---|
393 | |
---|
394 | #include <stdio.h> |
---|
395 | #include <unistd.h> |
---|
396 | |
---|
397 | void _Heap_Walk( |
---|
398 | Heap_Control *the_heap, |
---|
399 | int source, |
---|
400 | boolean do_dump |
---|
401 | ) |
---|
402 | { |
---|
403 | Heap_Block *the_block = 0; /* avoid warnings */ |
---|
404 | Heap_Block *next_block = 0; /* avoid warnings */ |
---|
405 | int notdone = 1; |
---|
406 | |
---|
407 | /* |
---|
408 | * We don't want to allow walking the heap until we have |
---|
409 | * transferred control to the user task so we watch the |
---|
410 | * system state. |
---|
411 | */ |
---|
412 | |
---|
413 | if ( !_System_state_Is_up( _System_state_Get() ) ) |
---|
414 | return; |
---|
415 | |
---|
416 | the_block = the_heap->start; |
---|
417 | |
---|
418 | if (do_dump == TRUE) { |
---|
419 | printf("\nPASS: %d start @ 0x%p final 0x%p, first 0x%p last 0x%p\n", |
---|
420 | source, the_heap->start, the_heap->final, |
---|
421 | the_heap->first, the_heap->last |
---|
422 | ); |
---|
423 | } |
---|
424 | |
---|
425 | /* |
---|
426 | * Handle the 1st block |
---|
427 | */ |
---|
428 | |
---|
429 | if (the_block->back_flag != HEAP_DUMMY_FLAG) { |
---|
430 | printf("PASS: %d Back flag of 1st block isn't HEAP_DUMMY_FLAG\n", source); |
---|
431 | } |
---|
432 | |
---|
433 | while (notdone) { |
---|
434 | if (do_dump == TRUE) { |
---|
435 | printf("PASS: %d Block @ 0x%p Back %d, Front %d", |
---|
436 | source, the_block, |
---|
437 | the_block->back_flag, the_block->front_flag); |
---|
438 | if ( _Heap_Is_block_free(the_block) ) { |
---|
439 | printf( " Prev 0x%p, Next 0x%p\n", |
---|
440 | the_block->previous, the_block->next); |
---|
441 | } else { |
---|
442 | printf("\n"); |
---|
443 | } |
---|
444 | } |
---|
445 | |
---|
446 | /* |
---|
447 | * Handle the last block |
---|
448 | */ |
---|
449 | |
---|
450 | if ( the_block->front_flag != HEAP_DUMMY_FLAG ) { |
---|
451 | next_block = _Heap_Next_block(the_block); |
---|
452 | if ( the_block->front_flag != next_block->back_flag ) { |
---|
453 | printf("PASS: %d Front and back flags don't match\n", source); |
---|
454 | printf(" Current Block: Back - %d, Front - %d", |
---|
455 | the_block->back_flag, the_block->front_flag); |
---|
456 | if (do_dump == TRUE) { |
---|
457 | if (_Heap_Is_block_free(the_block)) { |
---|
458 | printf(" Prev 0x%p, Next 0x%p\n", |
---|
459 | the_block->previous, the_block->next); |
---|
460 | } else { |
---|
461 | printf("\n"); |
---|
462 | } |
---|
463 | } else { |
---|
464 | printf("\n"); |
---|
465 | } |
---|
466 | printf(" Next Block: Back - %d, Front - %d", |
---|
467 | next_block->back_flag, next_block->front_flag); |
---|
468 | if (do_dump == TRUE) { |
---|
469 | if (_Heap_Is_block_free(next_block)) { |
---|
470 | printf(" Prev 0x%p, Next 0x%p\n", |
---|
471 | the_block->previous, the_block->next); |
---|
472 | } else { |
---|
473 | printf("\n"); |
---|
474 | } |
---|
475 | } else { |
---|
476 | printf("\n"); |
---|
477 | } |
---|
478 | } |
---|
479 | } |
---|
480 | |
---|
481 | if (the_block->front_flag == HEAP_DUMMY_FLAG) |
---|
482 | notdone = 0; |
---|
483 | else |
---|
484 | the_block = next_block; |
---|
485 | } |
---|
486 | } |
---|