42_KFS/headers/memory.h

#pragma once

#include <stddef.h>
#include <stdint.h>

#define PRESENT    (1 << 0)
#define RW         (1 << 1)
#define SUPERVISOR (0 << 2)
#define ACCESSED   (1 << 4)
#define INIT_FLAGS (PRESENT | RW | SUPERVISOR)
#define PAGE_SIZE  4096
#define PT_SIZE    1024
#define PD_SIZE    1024
#define PAGE_MASK  0xFFFFF000
#define HEAP_END   0xC0000000
#define HEAP_START ((uint32_t) & _kernel_end - HEAP_END)
#define PT_START   256

#define GET_PAGE_ADDR(pd_index, pt_index)                                      \
	(((pd_index * 1024) + pt_index) * 4096)

extern uint32_t _kernel_end;
extern uint32_t boot_page_directory;
extern uint32_t *page_directory;
extern uint32_t page_table_default[1024];

uint32_t *virt_to_phys(uint32_t *virt_addr);
void init_memory(void);
void *alloc_frames(size_t size);
int free_frames(void *frame_ptr, size_t size);
void *alloc_pages(size_t size);
int free_pages(void *page_ptr, size_t size);
void init_page_table(uint32_t page_table[1024], uint16_t start);
int16_t add_page_table(uint16_t pd_index);