vulcanos/kernel/mem/kheap.c

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2021-02-03 15:59:42 +01:00
#include "kheap.h"
#include "paging.h"
#include "../libc/panic.h"
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) {
// First check if new size is greater than older one
ASSERT(new_size > heap->end_address - heap->start_address);
// Get nearest page boundary
if((new_size&0xFFFFF000) != 0) {
new_size &= 0xFFFFF000;
new_size += 0x1000;
}
// Check if new size is not greater than maximum size
ASSERT(heap->start_address+new_size <= heap->max_address);
uint32_t old_size = heap->end_address - 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_address = heap->start_address+new_size;
}
static uint32_t contract(uint32_t new_size, heap_t *heap) {
ASSERT(new_size < heap->end_address-heap->start_address);
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_address - 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_address = 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) {
// 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));
ASSERT(start%0x1000 == 0);
ASSERT(end_addr%0x1000 == 0);
// Initialize the index
heap->index = place_ordered_array((void*)start, HEAP_INDEX_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_address = end_addr;
heap->max_address = max;
heap->supervisor = supervisor;
heap->readonly = readonly;
header_t *hole = (header_t*)start;
hole->size = end_addr - 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_address - heap->start_address;
uint32_t old_end_addr = heap->end_address;
// Allocate more space
expand(old_len+new_size, heap);
uint32_t new_len = heap->end_address - 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);
}
header_t *origin_hole_head = (header_t*)lookup_ordered_array(it, &heap->index);
uint32_t origin_hole_p = (uint32_t)origin_hole_head;
uint32_t origin_hole_s = origin_hole_head->size;
// Check if we should split the hole into two parts
if(origin_hole_s-new_size < sizeof(header_t)+sizeof(footer_t)) {
// Increase the requested size to the size of the hole we found
size += origin_hole_s-new_size;
new_size = origin_hole_s;
}
// Check if we need to page-align data
if(page_align && origin_hole_p&0xFFFFF000) {
uint32_t new_loc = origin_hole_p + 0x1000 - (origin_hole_p&0xFFF) - sizeof(header_t);
header_t *hole_header = (header_t*)origin_hole_p;
hole_header->size = 0x1000 - (origin_hole_p&0xFFF) - sizeof(header_t);
hole_header->magic = HEAP_MAGIC;
hole_header->is_hole = 1;
footer_t *hole_footer = (footer_t*)((uint32_t)new_loc - sizeof(header_t));
hole_footer->magic = HEAP_MAGIC;
hole_footer->header = hole_header;
origin_hole_p = new_loc;
origin_hole_s = origin_hole_s - hole_header->size;
} else
remove_ordered_array(it, &heap->index); // Remove hole, since we don't need it anymore
// Rewrite original header
header_t *block_head = (header_t*)origin_hole_p;
block_head->magic = HEAP_MAGIC;
block_head->is_hole = 0;
block_head->size = new_size;
// and the footer
footer_t *block_foot = (footer_t*)(origin_hole_p + sizeof(header_t) + size);
block_foot->magic = HEAP_MAGIC;
block_foot->header = block_head;
// Check if we need to write a new hole after the allocated block
if(origin_hole_s - new_size > 0) {
header_t *hole_head = (header_t*)(origin_hole_p + sizeof(header_t) + size + sizeof(footer_t));
hole_head->magic = HEAP_MAGIC;
hole_head->is_hole = 1;
hole_head->size = origin_hole_s - new_size;
footer_t *hole_foot = (footer_t*)((uint32_t)hole_head + origin_hole_s - new_size - sizeof(footer_t));
if((uint32_t)hole_foot < heap->end_address) {
hole_foot->magic = HEAP_MAGIC;
hole_foot->header = hole_head;
}
// Add new hole to the data structure
insert_ordered_array((void*)hole_head, &heap->index);
}
// Return the block header
return (void*)((uint32_t)block_head+sizeof(header_t));
}
void free(void *p, heap_t *heap) {
// Check null pointers
if(p == 0)
return;
// Retrieve data
header_t *head = (header_t*)((uint32_t)p - sizeof(header_t));
footer_t *foot = (footer_t*)((uint32_t)head + head->size - sizeof(footer_t));
ASSERT(head->magic == HEAP_MAGIC);
ASSERT(foot->magic == HEAP_MAGIC);
head->is_hole = 1; // Make this a hole
int8_t add_to_free_hole = 1; // Add this header to free holes
// Left unify
footer_t *test_foot = (footer_t*)((uint32_t)head - sizeof(footer_t));
if(test_foot->magic == HEAP_MAGIC && test_foot->header->is_hole == 1 ) {
uint32_t cache_s = head->size; // Store current size
head = test_foot->header; // Rewrite header into new one
foot->header = head; // Point footer to the new header
head->size += cache_s; // Increase size
add_to_free_hole = 0; // Header already in the structure.
}
// Right unify
header_t *test_head = (header_t*)((uint32_t)foot + sizeof(footer_t));
if(test_head->magic == HEAP_MAGIC && test_head->is_hole) {
head->size += test_head->size; // Increase size
test_foot = (footer_t*)((uint32_t)test_foot + test_head->size - sizeof(footer_t));
foot = test_foot;
// Find and remove this header from the structure
uint32_t it = 0;
while((it < heap->index.size) && (lookup_ordered_array(it, &heap->index) != (void*)test_head))
it++;
// Check if we actually found something
ASSERT(it < heap->index.size);
// Remove that item
remove_ordered_array(it, &heap->index);
}
// If footer is located at the end, we can contract the heap
if((uint32_t)foot+sizeof(footer_t) == heap->end_address) {
uint32_t old_len = heap->end_address-heap->start_address;
uint32_t new_len = contract((uint32_t)head - heap->start_address, heap);
// Check dimensions after resizing
if(head->size - (old_len-new_len) > 0) {
// Dimensions is still a positive value, so we can resize
head->size -= old_len-new_len;
foot = (footer_t*)((uint32_t)head + head->size - sizeof(footer_t));
foot->magic = HEAP_MAGIC;
foot->header = head;
} else {
// Remove block from the structure
uint32_t it = 0;
while((it < heap->index.size) && (lookup_ordered_array(it, &heap->index) != (void*)test_head))
it++;
// If we didn't find that block we haven't nothing to remove
if(it < heap->index.size)
remove_ordered_array(it, &heap->index);
}
}
// If required by the user, add that block to the structure
if(add_to_free_hole == 1)
insert_ordered_array((void*)head, &heap->index);
}