diff --git a/kernel/paging.c b/kernel/paging.c index 321a404..1bb1f20 100644 --- a/kernel/paging.c +++ b/kernel/paging.c @@ -1,21 +1,17 @@ -#include "paging.h" -#include "io.h" #include -#include +#include +#include "io.h" +#include "paging.h" page_directory_entry_t *page_directory = (page_directory_entry_t *)0x200000; page_table_entry_t *page_table = (page_table_entry_t *)0x201000; -page_table_entry_t *heap_page_table = (page_table_entry_t *)0x202000; // Helper function to set up the page directory entry void set_page_directory(page_directory_entry_t *dir) { - for (int i = 0; i < PAGE_DIRECTORY_SIZE; i++) { - dir[i].present = 0; - } + // Set first PDE dir[0].present = 1; dir[0].rw = 1; - dir[0].user = 0; - dir[0].frame = (uint32_t)page_table >> 12; + dir[0].addr = (uint32_t)page_table >> 12; } // Helper function to set up the page table entry @@ -23,12 +19,8 @@ void set_page_table(page_table_entry_t *table) { for (int i = 0; i < PAGE_TABLE_SIZE; i++) { // Set up page table entries with identity mapping table[i].present = 1; - table[i].rw = 1; // Read/Write - table[i].user = 0; // Kernel mode - table[i].write_through = 0; - table[i].cache_disabled = 0; - table[i].accessed = 0; - table[i].frame = i; // Identity mapping + table[i].rw = 1; // Read/Write + table[i].addr = i; // Identity mapping } } @@ -47,26 +39,13 @@ void enable_paging() { // Initialize paging: set up the page directory and enable paging void paging_init() { + // Zero out the tables + memset(page_directory, 0x00, PAGE_DIRECTORY_SIZE * sizeof *page_directory); + memset(page_table, 0x00, PAGE_TABLE_SIZE * sizeof *page_table); + // Set up identity-mapped page directory + table set_page_directory(page_directory); set_page_table(page_table); - // === Set up heap mapping at 0xC0100000 === - for (int i = 0; i < PAGE_TABLE_SIZE; i++) { - heap_page_table[i].present = 1; - heap_page_table[i].rw = 1; - heap_page_table[i].user = 0; - heap_page_table[i].write_through = 0; - heap_page_table[i].cache_disabled = 0; - heap_page_table[i].accessed = 0; - heap_page_table[i].frame = (256 + i); // Start physical heap at 1MB (256*4KB = 1MB) - } - - // Index 772 = 0xC0100000 / 4MB - page_directory[772].present = 1; - page_directory[772].rw = 1; - page_directory[772].user = 0; - page_directory[772].frame = (uint32_t)heap_page_table >> 12; - enable_paging(); } diff --git a/kernel/paging.h b/kernel/paging.h index 01e73aa..57b2253 100644 --- a/kernel/paging.h +++ b/kernel/paging.h @@ -10,31 +10,31 @@ // Page Directory and Page Table structure typedef struct { - uint32_t present : 1; // Present bit (1: page is present in memory) - uint32_t rw : 1; // Read-Write bit (1: page is read-write) - uint32_t user : 1; // User-supervisor bit (1: user mode access) - uint32_t write_through : 1; // Write-through cache - uint32_t cache_disabled : 1; // Cache disabled - uint32_t accessed : 1; // Accessed bit - uint32_t reserved : 1; // Reserved bit - uint32_t page_size : 1; // Page size (0: 4KB, 1: 4MB) - uint32_t global : 1; // Global page (can be used across different processes) - uint32_t available : 3; // Available bits for the system - uint32_t frame : 20; // Frame address (physical address) + uint32_t present : 1; // Present bit (1: page is present in memory) + uint32_t rw : 1; // Read-Write bit (1: page is read-write) + uint32_t user : 1; // User-supervisor bit (1: user mode access) + uint32_t write_through : 1; // Write-through cache + uint32_t cache_disabled : 1; // Cache disabled + uint32_t accessed : 1; // Accessed bit + uint32_t dirty : 1; // Dirty bit + uint32_t attribute : 1; // Page size (0: 4KB, 1: 4MB) + uint32_t global : 1; // Global page (can be used across different processes) + uint32_t reserved : 3; // Unused + uint32_t addr : 20; // Page frame address (physical address) } __attribute__((packed)) page_table_entry_t; // Define page directory entry typedef struct { - uint32_t present : 1; - uint32_t rw : 1; - uint32_t user : 1; - uint32_t write_through : 1; - uint32_t cache_disabled : 1; - uint32_t accessed : 1; - uint32_t reserved : 1; - uint32_t zero : 5; // Must be zero for page directory - uint32_t reserved_2 : 7; // Reserved bits - uint32_t frame : 20; // Frame address of the page table + uint32_t present : 1; // Present bit (1: PTE is present in memory) + uint32_t rw : 1; // Read-Write bit (1: pages are read-write) + uint32_t user : 1; // User-supervisor bit (1: user mode access) + uint32_t write_through : 1; // Write-through cache + uint32_t cache_disabled : 1; // Cache disabled + uint32_t accessed : 1; // Accessed bit + uint32_t available : 1; // Unused + uint32_t page_size : 1; // Page size (0: 4KB, 1: 4MB) + uint32_t available_2 : 4; // Unused + uint32_t addr : 20; // Page table address } __attribute__((packed)) page_directory_entry_t; extern page_directory_entry_t *page_directory; diff --git a/kernel/threading.c b/kernel/threading.c index c7b6ba5..64e22a7 100644 --- a/kernel/threading.c +++ b/kernel/threading.c @@ -1,9 +1,8 @@ +#include +#include #include "malloc.h" #include "print.h" #include "threading.h" -#include "types.h" -#include "utils.h" -#include #define MAX_THREADS 16 // Maximum number of threads #define THREAD_STACK_SIZE 8192 // Stack size for each thread diff --git a/kernel/utils.h b/kernel/utils.h index 53fab8a..88f5d06 100644 --- a/kernel/utils.h +++ b/kernel/utils.h @@ -11,6 +11,4 @@ char* itoa(int value, char* str, int base); // Convert unsigned integer to string (base is typically 10, 16, etc.) char* utoa(unsigned int value, char* str, int base); -void *memset(void *dest, int value, size_t len); - #endif // UTILS_H