vulcanos/kernel/mem/kheap.c

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2019-09-27 20:24:29 +02:00
#include "kheap.h"
#include "paging.h"
// TODO: add assert
extern uint32_t end;
uint32_t placement_addr = (uint32_t)&end;
extern page_directory_t *kernel_directory;
heap_t *kheap = 0;
uint32_t kmalloc_int(uint32_t sz, int32_t align, uint32_t *phys) {
if(kheap != 0) {
void *addr = alloc(sz, (uint8_t)align, kheap);
if(phys != 0) {
page_t *page = get_page((uint32_t)addr, 0, kernel_directory);
*phys = page->fr*0x1000 + ((uint32_t)addr&0xFFF);
}
return (uint32_t)addr;
} else {
if(align == 1 && (placement_addr & 0xFFFFF000)) {
placement_addr &= 0xFFFFF000;
placement_addr += 0x1000;
}
if(phys)
*phys = placement_addr;
uint32_t tmp = placement_addr;
placement_addr += sz;
return tmp;
}
}
void kfree(void *p) {
free(p, kheap);
}
uint32_t kmalloc_a(uint32_t sz) {
return kmalloc_int(sz, 1, 0);
}
uint32_t kmalloc_p(uint32_t sz, uint32_t *phys) {
return kmalloc_int(sz, 0, phys);
}
uint32_t kmalloc_ap(uint32_t sz, uint32_t *phys) {
return kmalloc_int(sz, 1, phys);
}
uint32_t kmalloc(uint32_t sz) {
return kmalloc_int(sz, 0, 0);
}
static void expand(uint32_t new_size, heap_t *heap) {
// Get nearest page boundary
if((new_size&0xFFFFF000) != 0) {
new_size &= 0xFFFFF000;
new_size += 0x1000;
}
uint32_t old_size = heap->end_adddress - heap->start_address;
uint32_t it = old_size;
while(it < new_size) {
alloc_frame(get_page(heap->start_address+it, 1, kernel_directory),
(heap->supervisor) ? 1 : 0, (heap->readonly) ? 0 : 1);
it += 0x1000; // Page size
}
heap->end_adddress = heap->start_address+new_size;
}
static uint32_t contract(uint32_t new_size, heap_t *heap) {
if(new_size&0x1000) {
new_size &= 0x1000;
new_size += 0x1000;
}
if(new_size < HEAP_MIN_SIZE)
new_size = HEAP_MIN_SIZE;
uint32_t old_size = heap->end_adddress - heap->start_address;
uint32_t it = old_size - 0x1000;
while(new_size < it) {
free_frame(get_page(heap->start_address+it,0, kernel_directory));
it -= 0x1000;
}
heap->end_adddress = heap->start_address + new_size;
return new_size;
}
static uint32_t find_smallest_hole(uint32_t size, uint8_t page_align, heap_t *heap) {
uint32_t it = 0;
// Find smallest hole that fit our request
while(it < heap->index.size) {
header_t *head = (header_t*)lookup_ordered_array(it, &heap->index);
if(page_align > 0) {
// IF page must be aligned
uint32_t location = (uint32_t)head;
uint32_t offset = 0;
if((((location+sizeof(header_t)) & 0xFFFFF000) != 0))
offset = 0x1000 - (location+sizeof(header_t))%0x1000;
uint32_t hole_size = (uint32_t)head->size - offset;
// Check if we can fit this page in that hole
if(hole_size >= (uint32_t)size)
break;
} else if(head->size >= size)
break;
it++;
}
// If we didn't find anything
if(it == heap->index.size)
return -1;
else
return it;
}
static uint8_t header_t_less_than(void *a, void *b) {
return (((header_t*)a)->size < ((header_t*)b)->size)?1:0;
}
heap_t *create_heap(uint32_t start, uint32_t end_addr, uint32_t max, uint8_t supervisor, uint8_t readonly) {
heap_t *heap = (heap_t*)kmalloc(sizeof(heap_t));
// Initialize the index
heap->index = place_ordered_array((void*)start, HEAP_MIN_SIZE, &header_t_less_than);
// Shift start address to the right
start += sizeof(type_t) * HEAP_INDEX_SIZE;
// Check if start address is page-aligned
if ((start & 0xFFFFF000) != 0) {
start &= 0xFFFFF000;
start += 0x1000;
}
// Store vars into heap
heap->start_address = start;
heap->end_adddress = end_addr;
heap->max_address = max;
heap->supervisor = supervisor;
heap->readonly = readonly;
header_t *hole = (header_t*)start;
hole->size = end - start;
hole->magic = HEAP_MAGIC;
hole->is_hole = 1;
insert_ordered_array((void*)hole, &heap->index);
return heap;
}
void *alloc(uint32_t size, uint8_t page_align, heap_t *heap) {
uint32_t new_size = size + sizeof(header_t) + sizeof(footer_t);
// Find smallest hole suitable
uint32_t it = find_smallest_hole(new_size, page_align, heap);
if((int32_t)it == -1) {
uint32_t old_len = heap->end_adddress - heap->start_address;
uint32_t old_end_addr = heap->end_adddress;
// Allocate more space
expand(old_len+new_size, heap);
uint32_t new_len = heap->end_adddress - heap->start_address;
it = 0;
uint32_t idx = -1; uint32_t value = 0x0;
while(it < heap->index.size) {
uint32_t tmp = (uint32_t)lookup_ordered_array(it, &heap->index);
if(tmp > value) {
value = tmp;
idx = it;
}
it++;
}
// If no headers has been found, add a new one
if((int32_t)idx == -1) {
header_t *head = (header_t*)old_end_addr;
head->magic = HEAP_MAGIC;
head->size = new_len - old_len;
head->is_hole = 1;
footer_t *foot = (footer_t*)(old_end_addr + head->size - sizeof(footer_t));
foot->magic = HEAP_MAGIC;
foot->header = head;
insert_ordered_array((void*)head, &heap->index);
} else {
header_t *head = lookup_ordered_array(idx, &heap->index);
head->size += new_len - old_len;
// Update the footer
footer_t *foot = (footer_t*)((uint32_t)head + head->size - sizeof(footer_t));
foot->header = head;
foot->magic = HEAP_MAGIC;
}
// Now we have enough space, so recall this function again
return alloc(size, page_align, heap);
}
}