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/slab.h>
21 #include <asm/rheap.h>
24 * Fixup a list_head, needed when copying lists. If the pointers fall
25 * between s and e, apply the delta. This assumes that
26 * sizeof(struct list_head *) == sizeof(unsigned long *).
28 static inline void fixup(unsigned long s
, unsigned long e
, int d
,
33 pp
= (unsigned long *)&l
->next
;
34 if (*pp
>= s
&& *pp
< e
)
37 pp
= (unsigned long *)&l
->prev
;
38 if (*pp
>= s
&& *pp
< e
)
42 /* Grow the allocated blocks */
43 static int grow(rh_info_t
* info
, int max_blocks
)
45 rh_block_t
*block
, *blk
;
48 unsigned long blks
, blke
;
50 if (max_blocks
<= info
->max_blocks
)
53 new_blocks
= max_blocks
- info
->max_blocks
;
55 block
= kmalloc(sizeof(rh_block_t
) * max_blocks
, GFP_KERNEL
);
59 if (info
->max_blocks
> 0) {
61 /* copy old block area */
62 memcpy(block
, info
->block
,
63 sizeof(rh_block_t
) * info
->max_blocks
);
65 delta
= (char *)block
- (char *)info
->block
;
67 /* and fixup list pointers */
68 blks
= (unsigned long)info
->block
;
69 blke
= (unsigned long)(info
->block
+ info
->max_blocks
);
71 for (i
= 0, blk
= block
; i
< info
->max_blocks
; i
++, blk
++)
72 fixup(blks
, blke
, delta
, &blk
->list
);
74 fixup(blks
, blke
, delta
, &info
->empty_list
);
75 fixup(blks
, blke
, delta
, &info
->free_list
);
76 fixup(blks
, blke
, delta
, &info
->taken_list
);
78 /* free the old allocated memory */
79 if ((info
->flags
& RHIF_STATIC_BLOCK
) == 0)
84 info
->empty_slots
+= new_blocks
;
85 info
->max_blocks
= max_blocks
;
86 info
->flags
&= ~RHIF_STATIC_BLOCK
;
88 /* add all new blocks to the free list */
89 blk
= block
+ info
->max_blocks
- new_blocks
;
90 for (i
= 0; i
< new_blocks
; i
++, blk
++)
91 list_add(&blk
->list
, &info
->empty_list
);
97 * Assure at least the required amount of empty slots. If this function
98 * causes a grow in the block area then all pointers kept to the block
101 static int assure_empty(rh_info_t
* info
, int slots
)
105 /* This function is not meant to be used to grow uncontrollably */
110 if (info
->empty_slots
>= slots
)
113 /* Next 16 sized block */
114 max_blocks
= ((info
->max_blocks
+ slots
) + 15) & ~15;
116 return grow(info
, max_blocks
);
119 static rh_block_t
*get_slot(rh_info_t
* info
)
123 /* If no more free slots, and failure to extend. */
124 /* XXX: You should have called assure_empty before */
125 if (info
->empty_slots
== 0) {
126 printk(KERN_ERR
"rh: out of slots; crash is imminent.\n");
130 /* Get empty slot to use */
131 blk
= list_entry(info
->empty_list
.next
, rh_block_t
, list
);
132 list_del_init(&blk
->list
);
143 static inline void release_slot(rh_info_t
* info
, rh_block_t
* blk
)
145 list_add(&blk
->list
, &info
->empty_list
);
149 static void attach_free_block(rh_info_t
* info
, rh_block_t
* blkn
)
156 unsigned long s
, e
, bs
, be
;
159 /* We assume that they are aligned properly */
164 /* Find the blocks immediately before and after the given one
170 list_for_each(l
, &info
->free_list
) {
171 blk
= list_entry(l
, rh_block_t
, list
);
176 if (next
== NULL
&& s
>= bs
)
185 /* If both are not null, break now */
186 if (before
!= NULL
&& after
!= NULL
)
190 /* Now check if they are really adjacent */
191 if (before
&& s
!= (before
->start
+ before
->size
))
194 if (after
&& e
!= after
->start
)
197 /* No coalescing; list insert and return */
198 if (before
== NULL
&& after
== NULL
) {
201 list_add(&blkn
->list
, &next
->list
);
203 list_add(&blkn
->list
, &info
->free_list
);
208 /* We don't need it anymore */
209 release_slot(info
, blkn
);
211 /* Grow the before block */
212 if (before
!= NULL
&& after
== NULL
) {
213 before
->size
+= size
;
217 /* Grow the after block backwards */
218 if (before
== NULL
&& after
!= NULL
) {
219 after
->start
-= size
;
224 /* Grow the before block, and release the after block */
225 before
->size
+= size
+ after
->size
;
226 list_del(&after
->list
);
227 release_slot(info
, after
);
230 static void attach_taken_block(rh_info_t
* info
, rh_block_t
* blkn
)
235 /* Find the block immediately before the given one (if any) */
236 list_for_each(l
, &info
->taken_list
) {
237 blk
= list_entry(l
, rh_block_t
, list
);
238 if (blk
->start
> blkn
->start
) {
239 list_add_tail(&blkn
->list
, &blk
->list
);
244 list_add_tail(&blkn
->list
, &info
->taken_list
);
248 * Create a remote heap dynamically. Note that no memory for the blocks
249 * are allocated. It will upon the first allocation
251 rh_info_t
*rh_create(unsigned int alignment
)
255 /* Alignment must be a power of two */
256 if ((alignment
& (alignment
- 1)) != 0)
257 return ERR_PTR(-EINVAL
);
259 info
= kmalloc(sizeof(*info
), GFP_KERNEL
);
261 return ERR_PTR(-ENOMEM
);
263 info
->alignment
= alignment
;
265 /* Initially everything as empty */
267 info
->max_blocks
= 0;
268 info
->empty_slots
= 0;
271 INIT_LIST_HEAD(&info
->empty_list
);
272 INIT_LIST_HEAD(&info
->free_list
);
273 INIT_LIST_HEAD(&info
->taken_list
);
279 * Destroy a dynamically created remote heap. Deallocate only if the areas
282 void rh_destroy(rh_info_t
* info
)
284 if ((info
->flags
& RHIF_STATIC_BLOCK
) == 0 && info
->block
!= NULL
)
287 if ((info
->flags
& RHIF_STATIC_INFO
) == 0)
292 * Initialize in place a remote heap info block. This is needed to support
293 * operation very early in the startup of the kernel, when it is not yet safe
296 void rh_init(rh_info_t
* info
, unsigned int alignment
, int max_blocks
,
302 /* Alignment must be a power of two */
303 if ((alignment
& (alignment
- 1)) != 0)
306 info
->alignment
= alignment
;
308 /* Initially everything as empty */
310 info
->max_blocks
= max_blocks
;
311 info
->empty_slots
= max_blocks
;
312 info
->flags
= RHIF_STATIC_INFO
| RHIF_STATIC_BLOCK
;
314 INIT_LIST_HEAD(&info
->empty_list
);
315 INIT_LIST_HEAD(&info
->free_list
);
316 INIT_LIST_HEAD(&info
->taken_list
);
318 /* Add all new blocks to the free list */
319 for (i
= 0, blk
= block
; i
< max_blocks
; i
++, blk
++)
320 list_add(&blk
->list
, &info
->empty_list
);
323 /* Attach a free memory region, coalesces regions if adjuscent */
324 int rh_attach_region(rh_info_t
* info
, unsigned long start
, int size
)
327 unsigned long s
, e
, m
;
330 /* The region must be aligned */
333 m
= info
->alignment
- 1;
341 if (IS_ERR_VALUE(e
) || (e
< s
))
344 /* Take final values */
348 /* Grow the blocks, if needed */
349 r
= assure_empty(info
, 1);
353 blk
= get_slot(info
);
358 attach_free_block(info
, blk
);
363 /* Detatch given address range, splits free block if needed. */
364 unsigned long rh_detach_region(rh_info_t
* info
, unsigned long start
, int size
)
367 rh_block_t
*blk
, *newblk
;
368 unsigned long s
, e
, m
, bs
, be
;
372 return (unsigned long) -EINVAL
;
374 /* The region must be aligned */
377 m
= info
->alignment
- 1;
385 if (assure_empty(info
, 1) < 0)
386 return (unsigned long) -ENOMEM
;
389 list_for_each(l
, &info
->free_list
) {
390 blk
= list_entry(l
, rh_block_t
, list
);
391 /* The range must lie entirely inside one free block */
393 be
= blk
->start
+ blk
->size
;
394 if (s
>= bs
&& e
<= be
)
400 return (unsigned long) -ENOMEM
;
403 if (bs
== s
&& be
== e
) {
404 /* Delete from free list, release slot */
405 list_del(&blk
->list
);
406 release_slot(info
, blk
);
410 /* blk still in free list, with updated start and/or size */
411 if (bs
== s
|| be
== e
) {
417 /* The front free fragment */
420 /* the back free fragment */
421 newblk
= get_slot(info
);
423 newblk
->size
= be
- e
;
425 list_add(&newblk
->list
, &blk
->list
);
431 /* Allocate a block of memory at the specified alignment. The value returned
432 * is an offset into the buffer initialized by rh_init(), or a negative number
433 * if there is an error.
435 unsigned long rh_alloc_align(rh_info_t
* info
, int size
, int alignment
, const char *owner
)
440 unsigned long start
, sp_size
;
442 /* Validate size, and alignment must be power of two */
443 if (size
<= 0 || (alignment
& (alignment
- 1)) != 0)
444 return (unsigned long) -EINVAL
;
446 /* Align to configured alignment */
447 size
= (size
+ (info
->alignment
- 1)) & ~(info
->alignment
- 1);
449 if (assure_empty(info
, 2) < 0)
450 return (unsigned long) -ENOMEM
;
453 list_for_each(l
, &info
->free_list
) {
454 blk
= list_entry(l
, rh_block_t
, list
);
455 if (size
<= blk
->size
) {
456 start
= (blk
->start
+ alignment
- 1) & ~(alignment
- 1);
457 if (start
+ size
<= blk
->start
+ blk
->size
)
464 return (unsigned long) -ENOMEM
;
467 if (blk
->size
== size
) {
468 /* Move from free list to taken list */
469 list_del(&blk
->list
);
472 /* Fragment caused, split if needed */
473 /* Create block for fragment in the beginning */
474 sp_size
= start
- blk
->start
;
478 spblk
= get_slot(info
);
479 spblk
->start
= blk
->start
;
480 spblk
->size
= sp_size
;
481 /* add before the blk */
482 list_add(&spblk
->list
, blk
->list
.prev
);
484 newblk
= get_slot(info
);
485 newblk
->start
= start
;
488 /* blk still in free list, with updated start and size
489 * for fragment in the end */
490 blk
->start
= start
+ size
;
491 blk
->size
-= sp_size
+ size
;
492 /* No fragment in the end, remove blk */
493 if (blk
->size
== 0) {
494 list_del(&blk
->list
);
495 release_slot(info
, blk
);
499 newblk
->owner
= owner
;
500 attach_taken_block(info
, newblk
);
505 /* Allocate a block of memory at the default alignment. The value returned is
506 * an offset into the buffer initialized by rh_init(), or a negative number if
509 unsigned long rh_alloc(rh_info_t
* info
, int size
, const char *owner
)
511 return rh_alloc_align(info
, size
, info
->alignment
, owner
);
514 /* Allocate a block of memory at the given offset, rounded up to the default
515 * alignment. The value returned is an offset into the buffer initialized by
516 * rh_init(), or a negative number if there is an error.
518 unsigned long rh_alloc_fixed(rh_info_t
* info
, unsigned long start
, int size
, const char *owner
)
521 rh_block_t
*blk
, *newblk1
, *newblk2
;
522 unsigned long s
, e
, m
, bs
= 0, be
= 0;
526 return (unsigned long) -EINVAL
;
528 /* The region must be aligned */
531 m
= info
->alignment
- 1;
539 if (assure_empty(info
, 2) < 0)
540 return (unsigned long) -ENOMEM
;
543 list_for_each(l
, &info
->free_list
) {
544 blk
= list_entry(l
, rh_block_t
, list
);
545 /* The range must lie entirely inside one free block */
547 be
= blk
->start
+ blk
->size
;
548 if (s
>= bs
&& e
<= be
)
553 return (unsigned long) -ENOMEM
;
556 if (bs
== s
&& be
== e
) {
557 /* Move from free list to taken list */
558 list_del(&blk
->list
);
562 attach_taken_block(info
, blk
);
568 /* blk still in free list, with updated start and/or size */
569 if (bs
== s
|| be
== e
) {
575 /* The front free fragment */
578 /* The back free fragment */
579 newblk2
= get_slot(info
);
581 newblk2
->size
= be
- e
;
583 list_add(&newblk2
->list
, &blk
->list
);
586 newblk1
= get_slot(info
);
588 newblk1
->size
= e
- s
;
589 newblk1
->owner
= owner
;
591 start
= newblk1
->start
;
592 attach_taken_block(info
, newblk1
);
597 /* Deallocate the memory previously allocated by one of the rh_alloc functions.
598 * The return value is the size of the deallocated block, or a negative number
599 * if there is an error.
601 int rh_free(rh_info_t
* info
, unsigned long start
)
603 rh_block_t
*blk
, *blk2
;
607 /* Linear search for block */
609 list_for_each(l
, &info
->taken_list
) {
610 blk2
= list_entry(l
, rh_block_t
, list
);
611 if (start
< blk2
->start
)
616 if (blk
== NULL
|| start
> (blk
->start
+ blk
->size
))
619 /* Remove from taken list */
620 list_del(&blk
->list
);
622 /* Get size of freed block */
624 attach_free_block(info
, blk
);
629 int rh_get_stats(rh_info_t
* info
, int what
, int max_stats
, rh_stats_t
* stats
)
639 h
= &info
->free_list
;
643 h
= &info
->taken_list
;
650 /* Linear search for block */
652 list_for_each(l
, h
) {
653 blk
= list_entry(l
, rh_block_t
, list
);
654 if (stats
!= NULL
&& nr
< max_stats
) {
655 stats
->start
= blk
->start
;
656 stats
->size
= blk
->size
;
657 stats
->owner
= blk
->owner
;
666 int rh_set_owner(rh_info_t
* info
, unsigned long start
, const char *owner
)
668 rh_block_t
*blk
, *blk2
;
672 /* Linear search for block */
674 list_for_each(l
, &info
->taken_list
) {
675 blk2
= list_entry(l
, rh_block_t
, list
);
676 if (start
< blk2
->start
)
681 if (blk
== NULL
|| start
> (blk
->start
+ blk
->size
))
690 void rh_dump(rh_info_t
* info
)
692 static rh_stats_t st
[32]; /* XXX maximum 32 blocks */
696 maxnr
= ARRAY_SIZE(st
);
699 "info @0x%p (%d slots empty / %d max)\n",
700 info
, info
->empty_slots
, info
->max_blocks
);
702 printk(KERN_INFO
" Free:\n");
703 nr
= rh_get_stats(info
, RHGS_FREE
, maxnr
, st
);
706 for (i
= 0; i
< nr
; i
++)
708 " 0x%lx-0x%lx (%u)\n",
709 st
[i
].start
, st
[i
].start
+ st
[i
].size
,
711 printk(KERN_INFO
"\n");
713 printk(KERN_INFO
" Taken:\n");
714 nr
= rh_get_stats(info
, RHGS_TAKEN
, maxnr
, st
);
717 for (i
= 0; i
< nr
; i
++)
719 " 0x%lx-0x%lx (%u) %s\n",
720 st
[i
].start
, st
[i
].start
+ st
[i
].size
,
721 st
[i
].size
, st
[i
].owner
!= NULL
? st
[i
].owner
: "");
722 printk(KERN_INFO
"\n");
725 void rh_dump_blk(rh_info_t
* info
, rh_block_t
* blk
)
728 "blk @0x%p: 0x%lx-0x%lx (%u)\n",
729 blk
, blk
->start
, blk
->start
+ blk
->size
, blk
->size
);