2 * A Remote Heap. Remote means that we don't touch the memory that the
3 * heap points to. Normal heap implementations use the memory they manage
4 * to place their list. We cannot do that because the memory we manage may
5 * have special properties, for example it is uncachable or of different
8 * Author: Pantelis Antoniou <panto@intracom.gr>
10 * 2004 (c) INTRACOM S.A. Greece. This file is licensed under
11 * the terms of the GNU General Public License version 2. This program
12 * is licensed "as is" without any warranty of any kind, whether express
15 #include <linux/types.h>
16 #include <linux/errno.h>
17 #include <linux/kernel.h>
19 #include <linux/err.h>
20 #include <linux/slab.h>
22 #include <asm/rheap.h>
25 * Fixup a list_head, needed when copying lists. If the pointers fall
26 * between s and e, apply the delta. This assumes that
27 * sizeof(struct list_head *) == sizeof(unsigned long *).
29 static inline void fixup(unsigned long s
, unsigned long e
, int d
,
34 pp
= (unsigned long *)&l
->next
;
35 if (*pp
>= s
&& *pp
< e
)
38 pp
= (unsigned long *)&l
->prev
;
39 if (*pp
>= s
&& *pp
< e
)
43 /* Grow the allocated blocks */
44 static int grow(rh_info_t
* info
, int max_blocks
)
46 rh_block_t
*block
, *blk
;
49 unsigned long blks
, blke
;
51 if (max_blocks
<= info
->max_blocks
)
54 new_blocks
= max_blocks
- info
->max_blocks
;
56 block
= kmalloc(sizeof(rh_block_t
) * max_blocks
, GFP_KERNEL
);
60 if (info
->max_blocks
> 0) {
62 /* copy old block area */
63 memcpy(block
, info
->block
,
64 sizeof(rh_block_t
) * info
->max_blocks
);
66 delta
= (char *)block
- (char *)info
->block
;
68 /* and fixup list pointers */
69 blks
= (unsigned long)info
->block
;
70 blke
= (unsigned long)(info
->block
+ info
->max_blocks
);
72 for (i
= 0, blk
= block
; i
< info
->max_blocks
; i
++, blk
++)
73 fixup(blks
, blke
, delta
, &blk
->list
);
75 fixup(blks
, blke
, delta
, &info
->empty_list
);
76 fixup(blks
, blke
, delta
, &info
->free_list
);
77 fixup(blks
, blke
, delta
, &info
->taken_list
);
79 /* free the old allocated memory */
80 if ((info
->flags
& RHIF_STATIC_BLOCK
) == 0)
85 info
->empty_slots
+= new_blocks
;
86 info
->max_blocks
= max_blocks
;
87 info
->flags
&= ~RHIF_STATIC_BLOCK
;
89 /* add all new blocks to the free list */
90 blk
= block
+ info
->max_blocks
- new_blocks
;
91 for (i
= 0; i
< new_blocks
; i
++, blk
++)
92 list_add(&blk
->list
, &info
->empty_list
);
98 * Assure at least the required amount of empty slots. If this function
99 * causes a grow in the block area then all pointers kept to the block
102 static int assure_empty(rh_info_t
* info
, int slots
)
106 /* This function is not meant to be used to grow uncontrollably */
111 if (info
->empty_slots
>= slots
)
114 /* Next 16 sized block */
115 max_blocks
= ((info
->max_blocks
+ slots
) + 15) & ~15;
117 return grow(info
, max_blocks
);
120 static rh_block_t
*get_slot(rh_info_t
* info
)
124 /* If no more free slots, and failure to extend. */
125 /* XXX: You should have called assure_empty before */
126 if (info
->empty_slots
== 0) {
127 printk(KERN_ERR
"rh: out of slots; crash is imminent.\n");
131 /* Get empty slot to use */
132 blk
= list_entry(info
->empty_list
.next
, rh_block_t
, list
);
133 list_del_init(&blk
->list
);
144 static inline void release_slot(rh_info_t
* info
, rh_block_t
* blk
)
146 list_add(&blk
->list
, &info
->empty_list
);
150 static void attach_free_block(rh_info_t
* info
, rh_block_t
* blkn
)
157 unsigned long s
, e
, bs
, be
;
160 /* We assume that they are aligned properly */
165 /* Find the blocks immediately before and after the given one
171 list_for_each(l
, &info
->free_list
) {
172 blk
= list_entry(l
, rh_block_t
, list
);
177 if (next
== NULL
&& s
>= bs
)
186 /* If both are not null, break now */
187 if (before
!= NULL
&& after
!= NULL
)
191 /* Now check if they are really adjacent */
192 if (before
&& s
!= (before
->start
+ before
->size
))
195 if (after
&& e
!= after
->start
)
198 /* No coalescing; list insert and return */
199 if (before
== NULL
&& after
== NULL
) {
202 list_add(&blkn
->list
, &next
->list
);
204 list_add(&blkn
->list
, &info
->free_list
);
209 /* We don't need it anymore */
210 release_slot(info
, blkn
);
212 /* Grow the before block */
213 if (before
!= NULL
&& after
== NULL
) {
214 before
->size
+= size
;
218 /* Grow the after block backwards */
219 if (before
== NULL
&& after
!= NULL
) {
220 after
->start
-= size
;
225 /* Grow the before block, and release the after block */
226 before
->size
+= size
+ after
->size
;
227 list_del(&after
->list
);
228 release_slot(info
, after
);
231 static void attach_taken_block(rh_info_t
* info
, rh_block_t
* blkn
)
236 /* Find the block immediately before the given one (if any) */
237 list_for_each(l
, &info
->taken_list
) {
238 blk
= list_entry(l
, rh_block_t
, list
);
239 if (blk
->start
> blkn
->start
) {
240 list_add_tail(&blkn
->list
, &blk
->list
);
245 list_add_tail(&blkn
->list
, &info
->taken_list
);
249 * Create a remote heap dynamically. Note that no memory for the blocks
250 * are allocated. It will upon the first allocation
252 rh_info_t
*rh_create(unsigned int alignment
)
256 /* Alignment must be a power of two */
257 if ((alignment
& (alignment
- 1)) != 0)
258 return ERR_PTR(-EINVAL
);
260 info
= kmalloc(sizeof(*info
), GFP_KERNEL
);
262 return ERR_PTR(-ENOMEM
);
264 info
->alignment
= alignment
;
266 /* Initially everything as empty */
268 info
->max_blocks
= 0;
269 info
->empty_slots
= 0;
272 INIT_LIST_HEAD(&info
->empty_list
);
273 INIT_LIST_HEAD(&info
->free_list
);
274 INIT_LIST_HEAD(&info
->taken_list
);
280 * Destroy a dynamically created remote heap. Deallocate only if the areas
283 void rh_destroy(rh_info_t
* info
)
285 if ((info
->flags
& RHIF_STATIC_BLOCK
) == 0 && info
->block
!= NULL
)
288 if ((info
->flags
& RHIF_STATIC_INFO
) == 0)
293 * Initialize in place a remote heap info block. This is needed to support
294 * operation very early in the startup of the kernel, when it is not yet safe
297 void rh_init(rh_info_t
* info
, unsigned int alignment
, int max_blocks
,
303 /* Alignment must be a power of two */
304 if ((alignment
& (alignment
- 1)) != 0)
307 info
->alignment
= alignment
;
309 /* Initially everything as empty */
311 info
->max_blocks
= max_blocks
;
312 info
->empty_slots
= max_blocks
;
313 info
->flags
= RHIF_STATIC_INFO
| RHIF_STATIC_BLOCK
;
315 INIT_LIST_HEAD(&info
->empty_list
);
316 INIT_LIST_HEAD(&info
->free_list
);
317 INIT_LIST_HEAD(&info
->taken_list
);
319 /* Add all new blocks to the free list */
320 for (i
= 0, blk
= block
; i
< max_blocks
; i
++, blk
++)
321 list_add(&blk
->list
, &info
->empty_list
);
324 /* Attach a free memory region, coalesces regions if adjuscent */
325 int rh_attach_region(rh_info_t
* info
, unsigned long start
, int size
)
328 unsigned long s
, e
, m
;
331 /* The region must be aligned */
334 m
= info
->alignment
- 1;
342 if (IS_ERR_VALUE(e
) || (e
< s
))
345 /* Take final values */
349 /* Grow the blocks, if needed */
350 r
= assure_empty(info
, 1);
354 blk
= get_slot(info
);
359 attach_free_block(info
, blk
);
364 /* Detatch given address range, splits free block if needed. */
365 unsigned long rh_detach_region(rh_info_t
* info
, unsigned long start
, int size
)
368 rh_block_t
*blk
, *newblk
;
369 unsigned long s
, e
, m
, bs
, be
;
373 return (unsigned long) -EINVAL
;
375 /* The region must be aligned */
378 m
= info
->alignment
- 1;
386 if (assure_empty(info
, 1) < 0)
387 return (unsigned long) -ENOMEM
;
390 list_for_each(l
, &info
->free_list
) {
391 blk
= list_entry(l
, rh_block_t
, list
);
392 /* The range must lie entirely inside one free block */
394 be
= blk
->start
+ blk
->size
;
395 if (s
>= bs
&& e
<= be
)
401 return (unsigned long) -ENOMEM
;
404 if (bs
== s
&& be
== e
) {
405 /* Delete from free list, release slot */
406 list_del(&blk
->list
);
407 release_slot(info
, blk
);
411 /* blk still in free list, with updated start and/or size */
412 if (bs
== s
|| be
== e
) {
418 /* The front free fragment */
421 /* the back free fragment */
422 newblk
= get_slot(info
);
424 newblk
->size
= be
- e
;
426 list_add(&newblk
->list
, &blk
->list
);
432 /* Allocate a block of memory at the specified alignment. The value returned
433 * is an offset into the buffer initialized by rh_init(), or a negative number
434 * if there is an error.
436 unsigned long rh_alloc_align(rh_info_t
* info
, int size
, int alignment
, const char *owner
)
441 unsigned long start
, sp_size
;
443 /* Validate size, and alignment must be power of two */
444 if (size
<= 0 || (alignment
& (alignment
- 1)) != 0)
445 return (unsigned long) -EINVAL
;
447 /* Align to configured alignment */
448 size
= (size
+ (info
->alignment
- 1)) & ~(info
->alignment
- 1);
450 if (assure_empty(info
, 2) < 0)
451 return (unsigned long) -ENOMEM
;
454 list_for_each(l
, &info
->free_list
) {
455 blk
= list_entry(l
, rh_block_t
, list
);
456 if (size
<= blk
->size
) {
457 start
= (blk
->start
+ alignment
- 1) & ~(alignment
- 1);
458 if (start
+ size
<= blk
->start
+ blk
->size
)
465 return (unsigned long) -ENOMEM
;
468 if (blk
->size
== size
) {
469 /* Move from free list to taken list */
470 list_del(&blk
->list
);
473 /* Fragment caused, split if needed */
474 /* Create block for fragment in the beginning */
475 sp_size
= start
- blk
->start
;
479 spblk
= get_slot(info
);
480 spblk
->start
= blk
->start
;
481 spblk
->size
= sp_size
;
482 /* add before the blk */
483 list_add(&spblk
->list
, blk
->list
.prev
);
485 newblk
= get_slot(info
);
486 newblk
->start
= start
;
489 /* blk still in free list, with updated start and size
490 * for fragment in the end */
491 blk
->start
= start
+ size
;
492 blk
->size
-= sp_size
+ size
;
493 /* No fragment in the end, remove blk */
494 if (blk
->size
== 0) {
495 list_del(&blk
->list
);
496 release_slot(info
, blk
);
500 newblk
->owner
= owner
;
501 attach_taken_block(info
, newblk
);
506 /* Allocate a block of memory at the default alignment. The value returned is
507 * an offset into the buffer initialized by rh_init(), or a negative number if
510 unsigned long rh_alloc(rh_info_t
* info
, int size
, const char *owner
)
512 return rh_alloc_align(info
, size
, info
->alignment
, owner
);
515 /* Allocate a block of memory at the given offset, rounded up to the default
516 * alignment. The value returned is an offset into the buffer initialized by
517 * rh_init(), or a negative number if there is an error.
519 unsigned long rh_alloc_fixed(rh_info_t
* info
, unsigned long start
, int size
, const char *owner
)
522 rh_block_t
*blk
, *newblk1
, *newblk2
;
523 unsigned long s
, e
, m
, bs
= 0, be
= 0;
527 return (unsigned long) -EINVAL
;
529 /* The region must be aligned */
532 m
= info
->alignment
- 1;
540 if (assure_empty(info
, 2) < 0)
541 return (unsigned long) -ENOMEM
;
544 list_for_each(l
, &info
->free_list
) {
545 blk
= list_entry(l
, rh_block_t
, list
);
546 /* The range must lie entirely inside one free block */
548 be
= blk
->start
+ blk
->size
;
549 if (s
>= bs
&& e
<= be
)
554 return (unsigned long) -ENOMEM
;
557 if (bs
== s
&& be
== e
) {
558 /* Move from free list to taken list */
559 list_del(&blk
->list
);
563 attach_taken_block(info
, blk
);
569 /* blk still in free list, with updated start and/or size */
570 if (bs
== s
|| be
== e
) {
576 /* The front free fragment */
579 /* The back free fragment */
580 newblk2
= get_slot(info
);
582 newblk2
->size
= be
- e
;
584 list_add(&newblk2
->list
, &blk
->list
);
587 newblk1
= get_slot(info
);
589 newblk1
->size
= e
- s
;
590 newblk1
->owner
= owner
;
592 start
= newblk1
->start
;
593 attach_taken_block(info
, newblk1
);
598 /* Deallocate the memory previously allocated by one of the rh_alloc functions.
599 * The return value is the size of the deallocated block, or a negative number
600 * if there is an error.
602 int rh_free(rh_info_t
* info
, unsigned long start
)
604 rh_block_t
*blk
, *blk2
;
608 /* Linear search for block */
610 list_for_each(l
, &info
->taken_list
) {
611 blk2
= list_entry(l
, rh_block_t
, list
);
612 if (start
< blk2
->start
)
617 if (blk
== NULL
|| start
> (blk
->start
+ blk
->size
))
620 /* Remove from taken list */
621 list_del(&blk
->list
);
623 /* Get size of freed block */
625 attach_free_block(info
, blk
);
630 int rh_get_stats(rh_info_t
* info
, int what
, int max_stats
, rh_stats_t
* stats
)
640 h
= &info
->free_list
;
644 h
= &info
->taken_list
;
651 /* Linear search for block */
653 list_for_each(l
, h
) {
654 blk
= list_entry(l
, rh_block_t
, list
);
655 if (stats
!= NULL
&& nr
< max_stats
) {
656 stats
->start
= blk
->start
;
657 stats
->size
= blk
->size
;
658 stats
->owner
= blk
->owner
;
667 int rh_set_owner(rh_info_t
* info
, unsigned long start
, const char *owner
)
669 rh_block_t
*blk
, *blk2
;
673 /* Linear search for block */
675 list_for_each(l
, &info
->taken_list
) {
676 blk2
= list_entry(l
, rh_block_t
, list
);
677 if (start
< blk2
->start
)
682 if (blk
== NULL
|| start
> (blk
->start
+ blk
->size
))
691 void rh_dump(rh_info_t
* info
)
693 static rh_stats_t st
[32]; /* XXX maximum 32 blocks */
697 maxnr
= ARRAY_SIZE(st
);
700 "info @0x%p (%d slots empty / %d max)\n",
701 info
, info
->empty_slots
, info
->max_blocks
);
703 printk(KERN_INFO
" Free:\n");
704 nr
= rh_get_stats(info
, RHGS_FREE
, maxnr
, st
);
707 for (i
= 0; i
< nr
; i
++)
709 " 0x%lx-0x%lx (%u)\n",
710 st
[i
].start
, st
[i
].start
+ st
[i
].size
,
712 printk(KERN_INFO
"\n");
714 printk(KERN_INFO
" Taken:\n");
715 nr
= rh_get_stats(info
, RHGS_TAKEN
, maxnr
, st
);
718 for (i
= 0; i
< nr
; i
++)
720 " 0x%lx-0x%lx (%u) %s\n",
721 st
[i
].start
, st
[i
].start
+ st
[i
].size
,
722 st
[i
].size
, st
[i
].owner
!= NULL
? st
[i
].owner
: "");
723 printk(KERN_INFO
"\n");
726 void rh_dump_blk(rh_info_t
* info
, rh_block_t
* blk
)
729 "blk @0x%p: 0x%lx-0x%lx (%u)\n",
730 blk
, blk
->start
, blk
->start
+ blk
->size
, blk
->size
);