pmm.h

#pragma once
 
// Scyther Physical Memory Manager by NDRAEY (c) 2023
// for SayoriOS
 
#include    "common.h"
#include    "multiboot.h"
 
typedef uint32_t pt_entry;
typedef uint32_t pd_entry;
 
extern size_t phys_memory_size;
extern size_t used_phys_memory_size;
 
extern size_t kernel_start;
extern size_t kernel_end;
 
#define     PAGE_SIZE               0x1000
#define     PAGE_OFFSET_MASK        0xFFF   
#define     PAGE_TABLE_INDEX_BITS   10  
#define     PAGE_TABLE_INDEX_MASK   0x3FF
 
#define     PAGE_PRESENT        (1U << 0)
#define     PAGE_WRITEABLE      (1U << 1)
#define     PAGE_USER           (1U << 2)
#define     PAGE_WRITE_THROUGH  (1U << 3)
#define     PAGE_CACHE_DISABLE  (1U << 4)
#define     PAGE_ACCESSED       (1U << 5)
#define     PAGE_DIRTY          (1U << 6)
#define     PAGE_GLOBAL         (1U << 8)
 
#define     PAGE_BITMAP_SIZE (131072 * 4)
 
#define     PD_INDEX(virt_addr) ((virt_addr) >> 22)
#define     PT_INDEX(virt_addr) (((virt_addr) >> 12) & 0x3ff)
 
typedef     uint32_t            virtual_addr_t;
typedef     uint32_t            physical_addr_t;
 
// The space where first page table starts
static uint32_t* page_directory_start = (uint32_t*)(0xffffffff - (4 * MB) + 1);
 
// The space where we can modify page directory
static uint32_t* page_directory_virt = (uint32_t*)(0xffffffff - (4 * KB) + 1);
 
 
extern void load_page_directory(size_t addr);
extern void enable_paging();
 
physical_addr_t phys_alloc_single_page();
physical_addr_t phys_alloc_multi_pages(size_t count);
void phys_free_single_page(physical_addr_t addr);
void phys_free_multi_pages(physical_addr_t addr, size_t count);
void map_single_page(physical_addr_t* page_dir, physical_addr_t physical, virtual_addr_t virtual, uint32_t flags);
void unmap_single_page(uint32_t* page_dir, virtual_addr_t virtual);
void map_pages(uint32_t* page_dir, physical_addr_t physical, virtual_addr_t virtual, size_t size, uint32_t flags);
void phys_not_enough_memory();
void blank_page_directory(uint32_t* pagedir_addr);
bool phys_is_used_page(physical_addr_t addr);
void phys_mark_page_entry(physical_addr_t addr, uint8_t used);
uint32_t phys_get_page_data(uint32_t* page_dir, virtual_addr_t virtual);
uint32_t virt2phys(const uint32_t *page_dir, virtual_addr_t virtual);
void init_paging();
uint32_t* get_kernel_page_directory();
 
void map_pages_overlapping(physical_addr_t* page_directory, size_t physical_start, size_t virtual_start, size_t size, uint32_t flags);
void unmap_pages_overlapping(physical_addr_t* page_directory, size_t virtual, size_t size);
void phys_set_flags(uint32_t* page_dir, virtual_addr_t virtual, uint32_t flags);