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mm stuff

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slinky55
2026-06-14 00:34:11 -05:00
parent 4e8de774ef
commit 53c5d7d40c
12 changed files with 527 additions and 51 deletions
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2
.gitignore vendored
View File

@@ -9,3 +9,5 @@
build
isodir
compiler*/

303
compile_commands.json
View File

@@ -1,19 +1,308 @@
[
{
"file": "kernel/kmain.c",
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"kernel/kmain.c",
"-o",
"obj/kernel/kmain.o",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel"
"-Ikernel",
"-o",
"obj/kernel/globals.o",
"kernel/globals.c"
],
"directory": "/home/slinky/source/RockOS",
"output": "obj/kernel/kmain.o"
"file": "/home/slinky/source/RockOS/kernel/globals.c",
"output": "/home/slinky/source/RockOS/obj/kernel/globals.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/kmain.o",
"kernel/kmain.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/kmain.c",
"output": "/home/slinky/source/RockOS/obj/kernel/kmain.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/idt.o",
"kernel/idt.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/idt.c",
"output": "/home/slinky/source/RockOS/obj/kernel/idt.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/drivers/pic/pic.o",
"kernel/drivers/pic/pic.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/drivers/pic/pic.c",
"output": "/home/slinky/source/RockOS/obj/kernel/drivers/pic/pic.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/drivers/vga/vga_stream_writer.o",
"kernel/drivers/vga/vga_stream_writer.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/drivers/vga/vga_stream_writer.c",
"output": "/home/slinky/source/RockOS/obj/kernel/drivers/vga/vga_stream_writer.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/drivers/ps2/ps2.o",
"kernel/drivers/ps2/ps2.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/drivers/ps2/ps2.c",
"output": "/home/slinky/source/RockOS/obj/kernel/drivers/ps2/ps2.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/gdt.o",
"kernel/gdt.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/gdt.c",
"output": "/home/slinky/source/RockOS/obj/kernel/gdt.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/memory/mm.o",
"kernel/memory/mm.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/memory/mm.c",
"output": "/home/slinky/source/RockOS/obj/kernel/memory/mm.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/interrupts.o",
"kernel/interrupts.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/interrupts.c",
"output": "/home/slinky/source/RockOS/obj/kernel/interrupts.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/lib/stream.o",
"kernel/lib/stream.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/lib/stream.c",
"output": "/home/slinky/source/RockOS/obj/kernel/lib/stream.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/lib/print.o",
"kernel/lib/print.c"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/lib/print.c",
"output": "/home/slinky/source/RockOS/obj/kernel/lib/print.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/drivers/pic/pic_stubs.o",
"kernel/drivers/pic/pic_stubs.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/drivers/pic/pic_stubs.S",
"output": "/home/slinky/source/RockOS/obj/kernel/drivers/pic/pic_stubs.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/drivers/pit/pit_stubs.o",
"kernel/drivers/pit/pit_stubs.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/drivers/pit/pit_stubs.S",
"output": "/home/slinky/source/RockOS/obj/kernel/drivers/pit/pit_stubs.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/drivers/ps2/ps2_stubs.o",
"kernel/drivers/ps2/ps2_stubs.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/drivers/ps2/ps2_stubs.S",
"output": "/home/slinky/source/RockOS/obj/kernel/drivers/ps2/ps2_stubs.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/boot/boot.o",
"kernel/boot/boot.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/boot/boot.S",
"output": "/home/slinky/source/RockOS/obj/kernel/boot/boot.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/gdt_stubs.o",
"kernel/gdt_stubs.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/gdt_stubs.S",
"output": "/home/slinky/source/RockOS/obj/kernel/gdt_stubs.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/common_stubs.o",
"kernel/common_stubs.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/common_stubs.S",
"output": "/home/slinky/source/RockOS/obj/kernel/common_stubs.o"
},
{
"arguments": [
"/home/slinky/opt/cross/bin/i686-elf-gcc",
"-c",
"-ffreestanding",
"-O2",
"-Wall",
"-Wextra",
"-Ikernel",
"-o",
"obj/kernel/idt_stubs.o",
"kernel/idt_stubs.S"
],
"directory": "/home/slinky/source/RockOS",
"file": "/home/slinky/source/RockOS/kernel/idt_stubs.S",
"output": "/home/slinky/source/RockOS/obj/kernel/idt_stubs.o"
}
]
]

2
kernel/boot/boot.S
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@@ -21,6 +21,8 @@ stack_top:
_start:
cli
mov $stack_top, %esp
push %ebx
push %eax
call kmain
loop:
jmp loop

12
kernel/common_stubs.S
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@@ -13,14 +13,4 @@ enable_interrupts:
.global io_wait
io_wait:
outb %al, $0x80
ret
.global load_grub_boot_struct
load_grub_boot_struct:
mov %ebx, grub_boot_struct_ptr
.section .bss
.align 4
.global grub_boot_struct_ptr
grub_boot_struct_ptr:
.int 0
ret

11
kernel/globals.c
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@@ -1,3 +1,12 @@
#include <lib/stream.h>
#include <stddef.h>
#include "multiboot.h"
print_stream_t* kout;
print_stream_t* kout;
multiboot_info* grub_boot_struct_ptr = NULL;
extern char __kernel_start;
extern char __kernel_end;
size_t kernel_size() {
return (size_t)(&__kernel_end - &__kernel_start);
}

6
kernel/interrupts.c
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@@ -44,9 +44,7 @@ void common_interrupt_handler(struct registers *args) {
case 14:
case 15:
case 16:
kprint("CPU Error: ");
kprint(err_messages[args->int_no]);
kprint("\n");
kprintf("CPU Error: %s", err_messages[args->int_no]);
break;
case 32:
// wake the PIT timer driver
@@ -58,7 +56,7 @@ void common_interrupt_handler(struct registers *args) {
break;
}
default:
kprint("Received unhandled interrupt\n");
kprintf("Received unhandled interrupt: %d\n", args->int_no);
return;
}
}

41
kernel/kmain.c
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@@ -1,10 +1,14 @@
#include "multiboot.h"
#include <lib/print.h>
#include <lib/stream.h>
#include <idt.h>
#include <stddef.h>
#include <stdint.h>
#include "memory/mm.h"
extern void init_idt();
extern void init_gdt();
extern void init_pic();
@@ -12,40 +16,51 @@ extern void init_pit();
extern int init_ps2();
extern void enable_interrupts();
extern void load_grub_boot_struct(void);
void* page = NULL;
extern void* grub_boot_struct_ptr;
void kmain(void)
{
void kmain(uint32_t magic, multiboot_info* mbi) {
extern print_stream_t vga_print_stream;
extern print_stream_t* kout;
kout = &vga_print_stream;
kout->trunc();
kprint("RockOS booting...\n");
kprintf("RockOS booting...\n");
init_gdt();
kprint("GDT set\n");
kprintf("GDT set\n");
init_idt();
kprint("IDT set\n");
kprintf("IDT set\n");
init_pic();
kprint("PIC initialized\n");
kprintf("PIC initialized\n");
init_pit();
kprint("PIT initialized\n");
kprintf("PIT initialized\n");
int result = init_ps2();
if (result == -1) {
kprint("PS2 init failed\n");
kprintf("PS2 init failed\n");
return;
}
kprint("PS2 initialized\n");
kprintf("PS2 initialized\n");
if (!(mbi->flags & (1 << 6))) {
return;
}
init_mm((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);
page = alloc_page();
kprintf("Allocated page at: 0x%x\n", (uint32_t)page);
free_page(page);
kprintf("Freed page");
enable_interrupts();
kprint("Interrupts enabled\n");
kprintf("Interrupts enabled\n");
while(1);
}

78
kernel/lib/print.c
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@@ -1,15 +1,91 @@
#include "print.h"
#include "stream.h"
#include <stdarg.h>
extern print_stream_t* kout;
static char* hex_chars = "0123456789abcdef";
void kprint(const char *str) {
static void kprint(const char *str) {
while (*str) {
kout->putchar(*str);
str++;
}
}
static void kputd(int d) {
if (d == 0) {
kout->putchar('0');
return;
}
char buffer[12];
int i = 0;
while (d > 0) {
buffer[i++] = '0' + (d % 10);
d /= 10;
}
for (int j = i - 1; j >= 0; j--) {
kout->putchar(buffer[j]);
}
}
static void kputx(unsigned int x) {
if (x == 0) {
kout->putchar('0');
return;
}
char buffer[8];
int i = 0;
while (x > 0) {
buffer[i++] = hex_chars[x & 0xF];
x >>= 4;
}
for (int j = i - 1; j >= 0; j--) {
kout->putchar(buffer[j]);
}
}
void kputc(const char c) {
kout->putchar(c);
}
void kprintf(const char* fmt, ...) {
va_list args;
va_start(args, fmt);
while (*fmt) {
if (*fmt == '%') {
fmt++;
switch (*fmt) {
case 's': {
const char* str = va_arg(args, const char*);
kprint(str);
break;
}
case 'd': {
int d = va_arg(args, int);
kputd(d);
break;
}
case 'x': {
unsigned int x = va_arg(args, unsigned int);
kputx(x);
break;
}
case '%':
kout->putchar('%');
break;
default:
kout->putchar('%');
kout->putchar(*fmt);
break;
}
fmt++;
} else {
kout->putchar(*fmt);
fmt++;
}
}
va_end(args);
}

2
kernel/lib/print.h
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@@ -1,7 +1,7 @@
#ifndef KLIBPRINT_H
#define KLIBPRINT_H
void kprint(const char* str);
void kputc(const char c);
void kprintf(const char* fmt, ...);
#endif

2
kernel/linker.ld
View File

@@ -3,6 +3,7 @@ ENTRY(_start)
SECTIONS
{
. = 2M;
__kernel_start = .;
.text BLOCK(4K) : ALIGN(4K)
{
@@ -25,4 +26,5 @@ SECTIONS
*(COMMON)
*(.bss)
}
__kernel_end = .;
}

103
kernel/memory/mm.c
View File

@@ -1,13 +1,46 @@
#include "multiboot.h"
#include <stddef.h>
extern uint8_t __kernel_start;
extern uint8_t __kernel_end;
#define PAGE_SIZE 4096
#define MAX_RAM 0xFFFFFFFF // 4GB
#define BITMAP_SIZE ((MAX_RAM / PAGE_SIZE) / 8)
static uint32_t max_address = 0;
static uint32_t total_available_memory = 0;
static uint8_t memory_bitmap[BITMAP_SIZE];
void parse_mmap(void* base, uint32_t limit) {
static void mark_free(uint32_t addr) {
uint32_t page_index = addr / PAGE_SIZE;
uint32_t byte_index = page_index / 8;
uint32_t bit_index = page_index % 8;
memory_bitmap[byte_index] &= ~(1 << bit_index);
}
static void mark_used(uint32_t addr) {
uint32_t page_index = addr / PAGE_SIZE;
uint32_t byte_index = page_index / 8;
uint32_t bit_index = page_index % 8;
memory_bitmap[byte_index] |= (1 << bit_index);
}
static uint32_t align(uint32_t addr, uint32_t len, uint32_t* usable_start, uint32_t* usable_end) {
uint32_t start = addr;
uint32_t end = addr + len;
*usable_start = (start + 4095) & ~0xFFF;
*usable_end = end & ~0xFFF;
return *usable_end - *usable_start;
}
static void parse_multiboot_mmap(void* base, uint32_t limit) {
multiboot_mmap_entry* entry = (multiboot_mmap_entry*)base;
void* end = (void*)((uint32_t)base + limit);
total_available_memory = 0;
while ((void*)entry < end) {
uint32_t entry_size = entry->size + sizeof(entry->size);
if (entry->type == 1) {
uint32_t region_start = (uint32_t)(entry->addr);
uint32_t region_end = (uint32_t)(entry->addr + entry->len);
@@ -15,23 +48,67 @@ void parse_mmap(void* base, uint32_t limit) {
max_address = region_end;
}
total_available_memory += entry->len;
// start breaking up the address range
// if it's safe (not kernel, not BIOS structures, etc..), find the corresponding page in our PMM, mark it free
// need to align start and end to 4kb
if (entry->len < 4096) {
uint32_t usable_start, usable_end, usable_size;
usable_size = align(region_start, entry->len, &usable_start, &usable_end);
if (usable_size <= 4096) {
continue;
}
for (uint32_t addr = region_start; addr < region_end; addr += 4096) {
// check for physical kernel address range
for (uint32_t addr = usable_start; addr < usable_end; addr += 4096) {
if (addr <= (uint32_t)&__kernel_end && addr >= (uint32_t)&__kernel_start) {
continue;
}
// check if this address range contains our multiboot structure
if (addr >= (uint32_t)entry && addr <= (uint32_t)entry + entry_size) {
continue;
}
// don't allow pages under 1MB
if (addr <= 0x200000) {
continue;
}
total_available_memory += 4096;
mark_free(addr);
}
}
entry = (multiboot_mmap_entry*)((uint32_t)entry + entry->size + sizeof(entry->size));
entry = (multiboot_mmap_entry*)((uint32_t)entry + entry_size);
}
}
void init_mm(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);
}
}
uint32_t total_free_memory() {
return total_available_memory;
}
void* alloc_page() {
for (uint32_t i = 0; i < BITMAP_SIZE; i++) {
uint8_t b = memory_bitmap[i];
if (b == 0xFF) {
continue;
}
for (int bit = 0; bit < 8; bit++) {
if ((b & (1 << bit)) == 0) {
uint32_t page_addr = (i * 8 + bit) * PAGE_SIZE;
mark_used(page_addr);
return (void*)page_addr;
}
}
}
return 0;
}
void free_page(void* addr) {
mark_free((uint32_t)addr);
}

16
kernel/memory/mm.h Normal file
View File

@@ -0,0 +1,16 @@
#ifndef KMM_H
#define KMM_H
#include <stdint.h>
typedef struct __attribute__((packed)) {
uint32_t addr;
} mem_page_t;
void init_mm(void* mmap_base, uint32_t mmap_limit);
uint32_t total_free_memory();
void* alloc_page();
void free_page(void* addr);
#endif