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boot page table works

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slinky55
2026-06-15 23:35:01 -05:00
parent 25da0f6a71
commit fe3725db99
7 changed files with 100 additions and 58 deletions
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2
kernel/boot/boot.S
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@@ -31,6 +31,8 @@ _start:
jmp *%ecx jmp *%ecx
higher: higher:
mov $stack_top, %esp mov $stack_top, %esp
mov $0xC0000000, %eax
add %eax, %ebx
push %ebx push %ebx
push %eax push %eax
call kmain call kmain

4
kernel/drivers/pic/pic.h
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@@ -1,5 +1,5 @@
#define PIC1_ADDR 0x20 #define PIC1_ADDR 0x20 + 0xC0000000
#define PIC2_ADDR 0xA0 #define PIC2_ADDR 0xA0 + 0xC0000000
#define PIC1_COMMAND PIC1_ADDR #define PIC1_COMMAND PIC1_ADDR
#define PIC1_DATA (PIC1_ADDR+1) #define PIC1_DATA (PIC1_ADDR+1)
#define PIC2_COMMAND PIC2_ADDR #define PIC2_COMMAND PIC2_ADDR

2
kernel/drivers/vga/vga_stream_writer.c
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@@ -5,7 +5,7 @@
#define VGA_WIDTH 80 #define VGA_WIDTH 80
#define VGA_HEIGHT 25 #define VGA_HEIGHT 25
#define VGA_MEMORY 0xB8000 #define VGA_MEMORY (0xB8000 + 0xC0000000)
enum vga_color { enum vga_color {
VGA_COLOR_BLACK = 0, VGA_COLOR_BLACK = 0,

52
kernel/kmain.c
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@@ -27,13 +27,30 @@ void kmain(uint32_t magic, multiboot_info* mbi) {
kout = &vga_print_stream; kout = &vga_print_stream;
kout->trunc(); kout->trunc();
kprintf("RockOS booting...\n"); kprintf("kernel start: 0x%x\n", &__kernel_start);
kprintf("kernel end: 0x%x\n", &__kernel_end);
uint32_t size = (&__kernel_end - &__kernel_start) / 1024;
kprintf("kernel size: %dKB\n", size);
if (!(mbi->flags & (1 << 6))) {
return;
}
kprintf("multiboot virtual address: 0x%x\n", mbi);
uint32_t mmap_virtual_addr = mbi->mmap_addr + 0xC0000000;
kprintf("mmap virtual address: 0x%x\n", mmap_virtual_addr);
init_pmm((void*)mmap_virtual_addr, mbi->mmap_length);
uint32_t mem_size = total_free_memory();
kprintf("Total available memory: %d MB\n", mem_size / 1024 / 1024);
kprintf("RockOS booting...\n");
init_gdt(); init_gdt();
kprintf("GDT set\n"); extern uint64_t gdt[5];
kprintf("GDT set @ 0x%x\n", &gdt);
init_idt(); init_idt();
kprintf("IDT set\n"); extern idt_entry idt[256];
kprintf("IDT set @ 0x%x\n", &idt);
init_pic(); init_pic();
kprintf("PIC initialized\n"); kprintf("PIC initialized\n");
@@ -41,30 +58,15 @@ void kmain(uint32_t magic, multiboot_info* mbi) {
init_pit(); init_pit();
kprintf("PIT initialized\n"); kprintf("PIT initialized\n");
int result = init_ps2(); // int result = init_ps2();
if (result == -1) { // if (result == -1) {
kprintf("PS2 init failed\n"); // kprintf("PS2 init failed\n");
return; // return;
} // }
kprintf("PS2 initialized\n"); // kprintf("PS2 initialized\n");
if (!(mbi->flags & (1 << 6))) {
return;
}
init_pmm((void*)mbi->mmap_addr, mbi->mmap_length);
uint32_t mem_size = total_free_memory();
kprintf("Total available memory: %d MB\n", mem_size / 1024 / 1024);
kprintf("__kernel_start: 0x%x\n", &__kernel_start);
kprintf("__kernel_end: 0x%x\n", &__kernel_end);
extern uint32_t page_directory[1024];
kprintf("page directory: 0x%x\n", &page_directory);
uint32_t size = (&__kernel_end - &__kernel_start) / 1024;
kprintf("kernel size: %dKB\n", size);
init_page_tables(); init_page_tables();
kprintf("Page tables reloaded"); kprintf("Page tables initialized\n");
while(1); while(1);
} }

87
kernel/memory/mm.c
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@@ -1,3 +1,4 @@
#include "lib/print.h"
#include "multiboot.h" #include "multiboot.h"
#include <stddef.h> #include <stddef.h>
@@ -5,10 +6,21 @@
extern uint8_t __kernel_start; extern uint8_t __kernel_start;
extern uint8_t __kernel_end; extern uint8_t __kernel_end;
extern uint32_t page_directory[1024];
extern void flush_tlb();
extern void disable_pae();
#define PAGE_SIZE 4096 #define PAGE_SIZE 4096
#define MAX_RAM 0xFFFFFFFF // 4GB #define MAX_RAM 0xFFFFFFFF // 4GB
#define BITMAP_SIZE ((MAX_RAM / PAGE_SIZE) / 8) #define BITMAP_SIZE ((MAX_RAM / PAGE_SIZE) / 8)
#define PAGE_TABLES 0xFFC00000
#define PAGE_DIRECTORY 0xFFFFF000
#define PAGE_PRESENT 0x1
#define PAGE_WRITABLE 0x2
#define PAGE_USER 0x4
static uint32_t max_address = 0; static uint32_t max_address = 0;
static uint32_t total_available_memory = 0; static uint32_t total_available_memory = 0;
static uint8_t memory_bitmap[BITMAP_SIZE]; static uint8_t memory_bitmap[BITMAP_SIZE];
@@ -57,7 +69,7 @@ static void parse_multiboot_mmap(void* base, uint32_t limit) {
uint32_t kernel_phys_start = (uint32_t)&__kernel_start - 0xC0000000; uint32_t kernel_phys_start = (uint32_t)&__kernel_start - 0xC0000000;
uint32_t kernel_phys_end = (uint32_t)&__kernel_end - 0xC0000000; uint32_t kernel_phys_end = (uint32_t)&__kernel_end - 0xC0000000;
for (uint32_t addr = usable_start; addr < usable_end; addr += 4096) { for (uint32_t addr = usable_start; addr < usable_end; addr += 4096) {
if (addr <= (uint32_t)&kernel_phys_end && addr >= (uint32_t)&kernel_phys_start) { if (addr <= kernel_phys_end && addr >= kernel_phys_start) {
continue; continue;
} }
@@ -78,22 +90,7 @@ static void parse_multiboot_mmap(void* base, uint32_t limit) {
} }
} }
void init_pmm(void* mmap_base, uint32_t mmap_limit) { static void* p_alloc_frame() {
for (int i = 0; i < BITMAP_SIZE; i++) {
memory_bitmap[i] = 0xFF;
}
if (mmap_base != NULL && mmap_limit > 0) {
parse_multiboot_mmap(mmap_base, mmap_limit);
}
}
uint32_t total_free_memory() {
return total_available_memory;
}
// this returns the virtual address of the physical page allocated
void* alloc_phys_page() {
for (uint32_t i = 0; i < BITMAP_SIZE; i++) { for (uint32_t i = 0; i < BITMAP_SIZE; i++) {
uint8_t b = memory_bitmap[i]; uint8_t b = memory_bitmap[i];
if (b == 0xFF) { if (b == 0xFF) {
@@ -104,7 +101,7 @@ void* alloc_phys_page() {
if ((b & (1 << bit)) == 0) { if ((b & (1 << bit)) == 0) {
uint32_t page_addr = (i * 8 + bit) * PAGE_SIZE; uint32_t page_addr = (i * 8 + bit) * PAGE_SIZE;
mark_used(page_addr); mark_used(page_addr);
return (void*)(page_addr + 0xC0000000); return (void*)page_addr;
} }
} }
} }
@@ -112,19 +109,59 @@ void* alloc_phys_page() {
return 0; return 0;
} }
void free_phys_page(void* addr) { static void p_free_frame(void* addr) {
mark_free((uint32_t)addr); mark_free((uint32_t)addr);
} }
extern uint32_t page_directory[1024]; static void map_page(uint32_t vaddr, uint32_t paddr, uint32_t flags) {
extern void flush_tlb(); uint32_t pde_entry = vaddr >> 22;
extern void disable_pae(); uint32_t pte_entry = (vaddr >> 12) & 0x3FF;
uint32_t* page_directory = (uint32_t*)PAGE_DIRECTORY;
if (page_directory[pde_entry] & PAGE_PRESENT == 0) {
uint32_t* new_table = (uint32_t*)p_alloc_frame();
page_directory[pde_entry] = (uint32_t)new_table | flags;
}
}
static void* p_alloc(uint32_t size_b, uint32_t vstart) {
uint32_t pages = (size_b + PAGE_SIZE - 1) / PAGE_SIZE;
for (uint32_t i = 0; i < pages; i++) {
uint32_t vaddr = vstart + i * PAGE_SIZE;
uint32_t paddr = (uint32_t)p_alloc_frame();
map_page(vaddr, paddr, PAGE_PRESENT | PAGE_WRITABLE);
}
return (void*)vstart;
}
void init_pmm(void* mmap_base, uint32_t mmap_limit) {
for (int i = 0; i < BITMAP_SIZE; i++) {
memory_bitmap[i] = 0xFF;
}
if (mmap_base != NULL && mmap_limit > 0) {
parse_multiboot_mmap(mmap_base, mmap_limit);
}
}
void init_page_tables() { void init_page_tables() {
uint32_t* kernel_table = alloc_phys_page(); uint32_t* kernel_table = p_alloc_frame();
for (int i = 0; i < 1024; i++) { for (int i = 0; i < 1024; i++) {
kernel_table[i] = (i * PAGE_SIZE) | 0x3; kernel_table[i] = (i * PAGE_SIZE) | 0x3;
} }
uint32_t* phys_table = kernel_table - 0xC000000; page_directory[768] = (uint32_t)(kernel_table) | 0x3;
page_directory[768] = (uint32_t)(phys_table) | 0x3; page_directory[0] = 0;
disable_pae();
flush_tlb(); flush_tlb();
} }
void* init_kheap() {
}
uint32_t total_free_memory() {
return total_available_memory;
}

8
kernel/memory/mm.h
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@@ -8,11 +8,9 @@ typedef struct __attribute__((packed)) {
} mem_page_t; } mem_page_t;
void init_pmm(void* mmap_base, uint32_t mmap_limit); void init_pmm(void* mmap_base, uint32_t mmap_limit);
void init_page_tables();
void* init_kheap();
uint32_t total_free_memory(); uint32_t total_free_memory();
void* alloc_page();
void free_page(void* addr);
void init_page_tables();
#endif #endif

3
kernel/memory/mm_stubs.S
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@@ -7,5 +7,8 @@ flush_tlb:
.global disable_pae .global disable_pae
disable_pae: disable_pae:
mov %cr4, %edx
and $0xFFFFFFEF, %edx
mov %edx, %cr4
ret ret