82 lines
2.7 KiB
C
82 lines
2.7 KiB
C
/**************************************
|
|
* VulcanOS Kernel *
|
|
* Developed by Marco 'icebit' Cetica *
|
|
* (c) 2019-2021 *
|
|
* Released under GPLv3 *
|
|
* https://github.com/ice-bit/iceOS *
|
|
***************************************/
|
|
#ifndef PAGING_H
|
|
#define PAGING_H
|
|
|
|
#include <stdint.h>
|
|
#include "../drivers/isr.h"
|
|
#include "kheap.h"
|
|
|
|
#define FRAME_SIZE 4096
|
|
#define PAGE_TABLE_SIZE 1024
|
|
#define PAGE_DIRECTORY_SIZE 1024
|
|
#define PAGE_NOT_PRESENT 0
|
|
#define PAGE_PRESENT 1
|
|
#define PAGE_READ_ONLY 0
|
|
#define PAGE_READ_WRITE 1
|
|
#define PAGE_USER 0
|
|
#define PAGE_SUPERVISOR 0
|
|
#define PAGE_SIZE_4KB 0
|
|
#define PAGE_SIZE_4MB 1
|
|
// Frames macros
|
|
#define FRAME_ALLOCATIONS_SECTION_SIZE 32
|
|
#define USED_FRAME_SECTION 0xFFFFFFFF
|
|
#define FREE_FRAME_SECTION 0x00000000
|
|
|
|
#define FRAME(addr) (addr/FRAME_SIZE)
|
|
#define FRAME_SECTION(frame) (frame/FRAME_ALLOCATIONS_SECTION_SIZE)
|
|
#define FRAME_OFFSET(frame) (frame%FRAME_ALLOCATIONS_SECTION_SIZE)
|
|
|
|
// Set physical memory to 15 MiB
|
|
#define PHYSICAL_MEM_SIZE 0x10000000
|
|
|
|
struct page { // Single page structure, from intel's developer manual
|
|
uint8_t pr : 1; // Present: 1 to map 4KB page
|
|
uint8_t rw : 1; // Read/Write mode
|
|
uint8_t us : 1; // if 0, user mode access aren't allowed to the page
|
|
uint8_t pw : 1; // Page-level write through
|
|
uint8_t pc : 1; // Page-level cache disable
|
|
uint8_t ac : 1; // 1 if we have accessed 4kb page
|
|
uint8_t di : 1; // 1 if page has been written(dirty)
|
|
uint8_t pa : 1; // Unused bit
|
|
uint8_t gl : 1; // 1 if page is global
|
|
uint8_t ig : 3; // Unused bit
|
|
uint32_t fr: 20; // Physical address of frame
|
|
} __attribute__((packed));
|
|
typedef struct page page_t;
|
|
|
|
typedef struct page_table {
|
|
page_t pages[PAGE_TABLE_SIZE];
|
|
} page_table_t;
|
|
|
|
/* Holds 2 arrays for each page directory
|
|
* one holds the physical address, while
|
|
* the other one holds the virtual address
|
|
* (to write/read to it) */
|
|
typedef struct page_directory {
|
|
page_table_t *page_tables_virtual[PAGE_DIRECTORY_SIZE];
|
|
uint32_t page_tables_physical[PAGE_DIRECTORY_SIZE];
|
|
} page_directory_t;
|
|
|
|
// Setup environment, page directories and enable paging
|
|
void init_paging();
|
|
// Perform the "enable-paging" operation to the right register
|
|
void enable_paging(page_directory_t *dir);
|
|
// Retrieve a pointer from the given page
|
|
page_t *get_page(uint32_t address, int32_t make, page_directory_t *dir);
|
|
// Identity map(phys = virtual addr) to access it as if paging wasn't enabled
|
|
void identity_map();
|
|
// Delete a frame
|
|
void free_frame(page_t *page);
|
|
// Allocate a new frame
|
|
void alloc_frame(page_t *page, int32_t is_super, int32_t is_write);
|
|
// Page faults handler(ISR recorder)
|
|
void page_fault(registers_t regs);
|
|
|
|
#endif
|