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Espresso 0.0.2a

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This commit is contained in:
David Goeke
2025-10-20 21:57:30 -05:00
parent 102d517097
commit ff6cba1164
59 changed files with 29272 additions and 773 deletions
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110
lib/mm/paging.c
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@ -1,82 +1,60 @@
#include <mm/pmm.h>
#include <string.h>
#include <mm_macros.h>
#include <stdio.h>
#include <mm/paging.h>
#include <mm/pmm.h>
#include <mm/heap.h>
#define PAGE_DIRECTORY_ENTRIES 1024
#define PAGE_TABLE_ENTRIES 1024
#define PAGE_SIZE 4096
#define PAGE_PRESENT 0x1
#define PAGE_WRITE 0x2
#define PAGE_SIZE 4096
typedef uint32_t page_directory_entry_t;
typedef uint32_t page_table_entry_t;
static page_directory_entry_t* page_directory = NULL; /* Will be allocated */
static page_table_entry_t* page_tables[PAGE_DIRECTORY_ENTRIES];
extern void _enable_paging_asm(void);
void paging_init(void)
{
/* Allocate and clear the page directory */
page_directory = (page_directory_entry_t*)alloc_page();
memset(page_directory, 0, PAGE_SIZE);
/* Allocate and set up the first identity-mapped page table (0-4MB) */
page_tables[0] = (page_table_entry_t*)alloc_page();
memset(page_tables[0], 0, PAGE_SIZE);
for (uint32_t i = 0; i < PAGE_TABLE_ENTRIES; i++)
{
page_tables[0][i] = (i * PAGE_SIZE) | 3; /* Present | RW */
}
page_directory[0] = ((uint32_t)page_tables[0]) | 3;
/* Allocate and clear the heap page table */
uint32_t heap_pd_index = HEAP_START >> 22; /* 0xC0000000 >> 22 = 768 */
page_tables[heap_pd_index] = (page_table_entry_t*)alloc_page();
memset(page_tables[heap_pd_index], 0, PAGE_SIZE);
/* Map 4MB heap pages */
for (uint32_t i = 0; i < PAGE_TABLE_ENTRIES; i++) /* 1024 pages = 4MB */
{
void* phys = alloc_page();
if (phys == 0)
{
printf("Out of physical memory during heap mapping!\n");
while (1);
}
page_tables[heap_pd_index][i] = ((uint32_t)phys & 0xFFFFF000) | 3; /* Present | RW */
}
page_directory[heap_pd_index] = ((uint32_t)page_tables[heap_pd_index]) | 3;
/* Load page directory */
asm volatile ("mov %0, %%cr3" : : "r"(page_directory));
/* Enable paging */
_enable_paging_asm();
}
static uint32_t* page_directory;
void map_page(void* phys_addr, void* virt_addr)
{
uint32_t pd_index = ((uint32_t)virt_addr >> 22) & 0x3FF;
uint32_t pt_index = ((uint32_t)virt_addr >> 12) & 0x3FF;
uint32_t pd_idx = ((uint32_t)virt_addr >> 22) & 0x3FF;
uint32_t pt_idx = ((uint32_t)virt_addr >> 12) & 0x3FF;
/* Allocate page table if necessary */
if (!(page_directory[pd_index] & 1))
uint32_t* page_table;
if (!(page_directory[pd_idx] & PAGE_PRESENT))
{
void* pt_phys = alloc_page();
page_tables[pd_index] = (page_table_entry_t*)((uint32_t)pt_phys + 0xC0000000); /* Map it higher */
memset(page_tables[pd_index], 0, PAGE_SIZE);
page_directory[pd_index] = ((uint32_t)pt_phys) | 0x3; /* Present, R/W */
page_table = (uint32_t*) pmm_alloc_page();
MEMSET(page_table, 0, PAGE_SIZE);
page_directory[pd_idx] = ((uint32_t)page_table) | PAGE_PRESENT | PAGE_WRITE;
}
else
{
page_table = (uint32_t*)(page_directory[pd_idx] & ~0xFFF);
}
page_table_entry_t* page_table = (page_table_entry_t*)((page_directory[pd_index] & 0xFFFFF000) + 0xC0000000);
page_table[pt_index] = ((uint32_t)phys_addr & 0xFFFFF000) | 0x3; /* Present, R/W */
asm volatile ("invlpg (%0)" :: "r" (virt_addr) : "memory");
page_table[pt_idx] = ((uint32_t)phys_addr) | PAGE_PRESENT | PAGE_WRITE;
}
void paging_init(void)
{
#ifdef _DEBUG
printf("[ PAGING ] Initializing paging...\n");
#endif
page_directory = (uint32_t*)pmm_alloc_page();
MEMSET(page_directory, 0, PAGE_SIZE);
for (uint32_t addr = 0; addr < 0x800000; addr += PAGE_SIZE)
{
map_page((void*) addr, (void*) addr); /* identity map first 8MB */
}
asm volatile("mov %0, %%cr3" :: "r"(page_directory));
uint32_t cr0;
asm volatile("mov %%cr0, %0" : "=r"(cr0));
cr0 |= 0x80000000;
asm volatile("mov %0, %%cr0" :: "r"(cr0));
#ifdef _DEBUG
printf("[ PAGING ] Paging initialized\n");
#endif
}