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#include <toxic/errno.h>
#include <toxic/string.h>
#include <toxic/math.h>
#include <toxic/kernel.h>
#include <mm/heap.h>
static int
heap_validate_table(
struct heap_table *tbl,
void *start,
void *end)
{
int ret = 0;
size_t tbl_size = (size_t)(end - start);
size_t tbl_pages = tbl_size / PAGE_SIZE;
if (tbl->count != tbl_pages)
ret = -EINVAL;
return ret;
}
static int
heap_validate_alignment(void *ptr)
{
return ((uint32_t)ptr % PAGE_SIZE) == 0;
}
int
heap_create(
struct heap *heap,
void *start,
void *end,
struct heap_table *tbl)
{
int ret = -EINVAL;
size_t tbl_size = HEAP_ENTRY_SIZE * tbl->count;
if (!heap_validate_alignment(start) ||
!heap_validate_alignment(end))
goto out;
memset(heap, 0, sizeof(struct heap));
heap->start_addr = start;
heap->table = tbl;
ret = heap_validate_table(tbl, start, end);
if (ret)
goto out;
memset(tbl->entries, 0, tbl_size);
out:
return ret;
}
static int
heap_entry_is_used(unsigned char entry)
{
return (entry & HEAP_ENTRY_USED_MASK) == HEAP_ENTRY_INUSE;
}
int
heap_get_start_page(
struct heap *heap,
uint32_t pages)
{
struct heap_table *tbl = heap->table;
int start_page = -1;
int cur_page = 0;
size_t i;
for (i = 0; i < tbl->count; i++) {
if (heap_entry_is_used(tbl->entries[i])) {
start_page = -1;
cur_page = 0;
continue;
}
if (start_page < 0)
start_page = i;
/* Did we find enough blocks? */
if (++cur_page == pages)
break;
}
if (start_page < 0)
return -ENOMEM;
return start_page;
}
void *
heap_page_to_addr(struct heap *heap, uint32_t page)
{
return heap->start_addr + (page * PAGE_SIZE);
}
uint32_t
heap_addr_to_page(struct heap *heap, void *ptr)
{
return (uint32_t)(ptr - heap->start_addr) / PAGE_SIZE;
}
void
heap_mark_pages_used(struct heap *heap, uint32_t start_page, uint32_t page_count)
{
int i;
uint32_t end = start_page + page_count - 1;
unsigned char cur = HEAP_ENTRY_IS_FIRST | HEAP_ENTRY_INUSE;
if (page_count > 1)
cur |= HEAP_ENTRY_HAS_NEXT;
for (i = start_page; i <= end; i++) {
heap->table->entries[i] = cur;
cur = HEAP_ENTRY_INUSE;
if (i != (end - 1))
cur |= HEAP_ENTRY_HAS_NEXT;
}
}
void
heap_mark_pages_free(struct heap *heap, uint32_t start_page)
{
int i;
struct heap_table *tbl = heap->table;
for (i = start_page; i < tbl->count; i++) {
unsigned char e = tbl->entries[i];
tbl->entries[i] = HEAP_ENTRY_FREE;
if (!(e & HEAP_ENTRY_HAS_NEXT))
break;
}
}
void *
heap_malloc_pages(struct heap *heap, uint32_t pages)
{
void *addr = 0;
uint32_t start_page = heap_get_start_page(heap, pages);
if (start_page < 0)
goto out;
addr = heap_page_to_addr(heap, start_page);
heap_mark_pages_used(heap, start_page, pages);
out:
return addr;
}
void *
heap_malloc(struct heap *heap, size_t size)
{
size_t aligned = roundup32((uint32_t) size, PAGE_SIZE);
uint32_t pages = aligned / PAGE_SIZE;
return heap_malloc_pages(heap, pages);
}
void
heap_free(struct heap *heap, void *ptr)
{
heap_mark_pages_free(heap, heap_addr_to_page(heap, ptr));
}
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