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#include <kernel/kmalloc.h>
#include <kernel/paging.h>
#include <kernel/pmem.h>
#include <kernel/asm.h>
#include <kernel/errno.h>
#include <kernel/panic.h>
#include <stdint.h>
static uintptr_t heap_start = KEND + 0xC0001000;
static uintptr_t heap_end = 0xFFFFF000;
static void *kbrk = NULL;
static struct mem_block *first = NULL;
void _request_page(void) {
uintptr_t paddr = pfa_alloc();
if (paddr == PFA_ALLOC_ERR)
panic("Out of physical memory");
uintptr_t vaddr = PGROUNDDN((uintptr_t)kbrk + PAGE_SIZE);
kbrk += PAGE_SIZE;
map_page(NULL, paddr, vaddr, PD_PRES | PD_RW);
}
void kmalloc_init(void) {
kbrk = (void*)(heap_start & 0xFFFFF000);
_request_page();
first = (struct mem_block*)kbrk;
first->start = (uintptr_t)kbrk + sizeof(struct mem_block);
first->size = 0;
first->alloc = 1;
first->next = NULL;
}
void* kmalloc(size_t sz) {
if (kbrk == NULL)
panic("Attmpted to malloc before initialization");
if ((uintptr_t)kbrk >= heap_end)
return NULL;
struct mem_block *temp = first;
while (temp->next != NULL) {
if (temp->size <= sz && temp->alloc == 0)
return (void*)temp->start;
temp = temp->next;
}
temp->next = (struct mem_block*)((uintptr_t)temp + sizeof(struct mem_block) + temp->size);
temp = temp->next;
temp->start = (uintptr_t)(temp + sizeof(struct mem_block));
temp->size = sz;
temp->alloc = 1;
temp->next = NULL;
return (void*)temp->start;
}
void kfree(void *ptr) {
struct mem_block *temp = first;
while (temp->next != NULL) {
if (temp->start == (uintptr_t)ptr) {
temp->alloc = 0;
return;
}
}
panic("Attempted to free memory not alloc'd");
}
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