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Espresso 0.0.0e

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This commit is contained in:
David Goeke
2025-06-13 18:03:39 -05:00
parent 6d366537dd
commit 1e5b4a765b
40 changed files with 742 additions and 718 deletions
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47
lib/mm/paging.c
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@ -3,6 +3,7 @@
#include <mm/paging.h>
#include <mm/pmm.h>
#include <mm/heap.h>
#define PAGE_DIRECTORY_ENTRIES 1024
#define PAGE_TABLE_ENTRIES 1024
@ -11,7 +12,7 @@
typedef uint32_t page_directory_entry_t;
typedef uint32_t page_table_entry_t;
static page_directory_entry_t* page_directory = (page_directory_entry_t*)0x9C000; /* Must be page-aligned */
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);
@ -19,37 +20,37 @@ extern void _enable_paging_asm(void);
void paging_init(void)
{
/* Allocate and clear the page directory */
page_directory = (uint32_t*)alloc_page();
memset(page_directory, 0, 4096);
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) */
uint32_t* first_table = (uint32_t*)alloc_page();
memset(first_table, 0, 4096);
for (uint32_t i = 0; i < 1024; i++)
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++)
{
first_table[i] = (i * 0x1000) | 3; /* Present | RW */
page_tables[0][i] = (i * PAGE_SIZE) | 3; /* Present | RW */
}
page_directory[0] = ((uint32_t)first_table) | 3;
page_directory[0] = ((uint32_t)page_tables[0]) | 3;
/* --- Map 4MB heap at 0xC0000000 --- */
uint32_t* heap_table = (uint32_t*)alloc_page();
memset(heap_table, 0, 4096);
for (uint32_t i = 0; i < 1024; i++) /* 256 pages = 1MB */
/* 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 */
{
uint32_t phys = (uint32_t)alloc_page();
void* phys = alloc_page();
if (phys == 0)
{
printf("Out of physical memory during heap mapping!\n");
while (1);
}
heap_table[i] = phys | 3; /* Present | RW */
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;
/* 0xC0000000 >> 22 == 768 */
page_directory[768] = ((uint32_t)heap_table) | 3;
// Load page directory
/* Load page directory */
asm volatile ("mov %0, %%cr3" : : "r"(page_directory));
/* Enable paging */
@ -67,16 +68,14 @@ void map_page(void* phys_addr, void* virt_addr)
void* pt_phys = alloc_page();
page_tables[pd_index] = (page_table_entry_t*)((uint32_t)pt_phys + 0xC0000000); /* Map it higher */
for (int i = 0; i < PAGE_TABLE_ENTRIES; i++)
{
page_tables[pd_index][i] = 0x00000002; /* Not present */
}
memset(page_tables[pd_index], 0, PAGE_SIZE);
page_directory[pd_index] = ((uint32_t)pt_phys) | 0x3; /* Present, R/W */
}
page_table_entry_t* page_table = (page_table_entry_t*)((page_directory[pd_index] & 0xFFFFF000) | 0xC0000000);
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");
}