mm stuff

.gitignore

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

compile_commands.json

@@ -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"
   }
 ]

kernel/boot/boot.S

@@ -21,6 +21,8 @@ stack_top:
 _start:
 	cli
 	mov $stack_top, %esp
+	push %ebx
+	push %eax
 	call kmain
 loop:
 	jmp loop

kernel/common_stubs.S

@@ -14,13 +14,3 @@ enable_interrupts:
 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

kernel/globals.c

@@ -1,3 +1,12 @@
 #include <lib/stream.h>
+#include <stddef.h>
+#include "multiboot.h"
 
 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);
+}

kernel/interrupts.c

@@ -44,9 +44,7 @@ void common_interrupt_handler(struct registers *args) {
         case 14:
         case 15:
         case 16:
-            kprint("CPU Error: ");
+            kprintf("CPU Error: %s", err_messages[args->int_no]);
-            kprint(err_messages[args->int_no]);
-            kprint("\n");
             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;
     }
 }

kernel/kmain.c

@@ -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(uint32_t magic, multiboot_info* mbi)  {
-
-void kmain(void) 
-{
   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);
 }

kernel/lib/print.c

@@ -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);
+}

kernel/lib/print.h

@@ -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

kernel/linker.ld

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

kernel/memory/mm.c

@@ -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;
+            uint32_t usable_start, usable_end, usable_size;
-
+            usable_size = align(region_start, entry->len, &usable_start, &usable_end);
-            // start breaking up the address range
+            if (usable_size <=  4096) {
-            // 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) {
                 continue;
             }
 
-            for (uint32_t addr = region_start; addr < region_end; addr += 4096) {
+            for (uint32_t addr = usable_start; addr < usable_end; addr += 4096) {
-                // check for physical kernel address range 
+                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);
+}

kernel/memory/mm.h

@@ -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