Implemented Higher Half Kernel!

- Minor makefile chnages
- stage3.c "prekernel", sets up memory stuff and jumps to kernel
- kernel is now at 0xC0000000 - 3GB+ "higher half"
- Added some global variables in memory/addresses.h

Makefile

@@ -24,12 +24,12 @@ filesystem: bootloader kernel $(C_FILES) $(FONTS)
 	@dd if=/dev/zero of=kern.iso bs=512 count=2880 status=none
 # TODO: Make this not so manual
 	@dd if=$(BUILD)/boot.bin      of=kern.iso bs=512 seek=0  conv=notrunc status=none
-	@dd if=$(BUILD)/filetable.bin of=kern.iso bs=512 seek=5  conv=notrunc status=none
+	@dd if=$(BUILD)/filetable.bin of=kern.iso bs=512 seek=15 conv=notrunc status=none
-	@dd if=$(BUILD)/kernel.bin    of=kern.iso bs=512 seek=6  conv=notrunc status=none
+	@dd if=$(BUILD)/kernel.bin    of=kern.iso bs=512 seek=16 conv=notrunc status=none
-	@dd if=$(BUILD)/term16n.bin   of=kern.iso bs=512 seek=46 conv=notrunc status=none
+	@dd if=$(BUILD)/term16n.bin   of=kern.iso bs=512 seek=56 conv=notrunc status=none
-	@dd if=$(BUILD)/testfont.bin  of=kern.iso bs=512 seek=50 conv=notrunc status=none
+	@dd if=$(BUILD)/testfont.bin  of=kern.iso bs=512 seek=60 conv=notrunc status=none
-	@dd if=$(SRC)/fs/test.txt     of=kern.iso bs=512 seek=54 conv=notrunc status=none
+	@dd if=$(SRC)/fs/test.txt     of=kern.iso bs=512 seek=64 conv=notrunc status=none
-	@dd if=$(BUILD)/calc.bin      of=kern.iso bs=512 seek=55 conv=notrunc status=none
+	@dd if=$(BUILD)/calc.bin      of=kern.iso bs=512 seek=65 conv=notrunc status=none
 
 $(BUILD):
 	@[ -d $(BUILD) ] || mkdir $(BUILD)
@@ -41,14 +41,18 @@ bootloader: $(SRC)/stage1.asm $(SRC)/stage2.asm
 	@$(AS) -fbin -o $(BUILD)/stage1.bin $(SRC)/stage1.asm
 	@echo "Assembling $(SRC)/stage2.asm..."
 	@$(AS) -fbin -o $(BUILD)/stage2.bin $(SRC)/stage2.asm
-	@cat $(BUILD)/stage1.bin $(BUILD)/stage2.bin > $(BUILD)/boot.bin
+	@echo "Compiling $(SRC)/stage3.c..."
+	@$(CC) $(CFLAGS) -Iinclude -o $(BUILD)/stage3.o -c $(SRC)/stage3.c
+	@$(LD) -T$(SRC)/stage3.ld -z notext --oformat binary -o $(BUILD)/stage3.bin $(BUILD)/stage3.o
+	@cat $(BUILD)/stage1.bin $(BUILD)/stage2.bin $(BUILD)/stage3.bin > $(BUILD)/boot.bin
+	@rm $(BUILD)/stage3.o
 
 # Kernel: This target is responsible for creating kernel.bin
 kernel: $(SRC)/kernel.c
 	@echo "Compiling $(SRC)/kernel.c..."
 	@$(CC) $(CFLAGS) -Iinclude -o $(BUILD)/kernel.o -c $(SRC)/kernel.c
 	@$(LD) -T$(SRC)/kernel.ld -z notext --oformat binary -o $(BUILD)/kernel.bin $(BUILD)/kernel.o
-	@rm $(BUILD)/*.o
+	@rm $(BUILD)/kernel.o
 
 $(C_FILES):
 	@echo "Compiling $(SRC)/$@.c..."

README.md

@@ -53,9 +53,10 @@ Graphics test: \
 _These images may be outdated, Idk_
 
 ## Known issues
-- If you run kernel.bin from shell, it will clear the memory map so when you load anything it will override the kernel code
+- If you run any of the bootloader stages or kernel form the shell, it will most likely break. (Maybe add an executable flag?)
 - fillCircle() in graphics.h is broken. No idea why, so no filled circles for you (i commented out the boundaryFill call in the function)
 - convertColor() doesn't work right, because i should be using floating point, but -mgeneral-regs-only doesn't let me :(
+- The soundtest command is very likely to get stuck on a note and play it forever. (Maybe a Sleep() bug?)
 - Not really an issue, bit QEMU's PIT is really slow and inacurate
 
 ## [Old Version](https://github.com/Tom-on64/old-kern)

include/disk/filesys.h

@@ -48,14 +48,15 @@ void updateFiletable() {
     // TODO: Update the filetable by writing data from memory to disk!
 }
 
-void readFile(char* filename, void* buffer) { // Hopefully the buffer is large enought :/
+uint8_t readFile(char* filename, void* buffer) { // Hopefully the buffer is large enought :/
     fileEntry_t* file = findFile(filename);
-    if (file == NULL) { return; } // File doesn't exist!
+    if (file == NULL) { return 1; } // File doesn't exist!
 
     diskRead(file->startAddress, file->length, buffer);
+    return 0; // Success
 }
 
-void writeFile(char* filename, void* buffer) { // TODO: Add length so we don't write too much/too little
+uint8_t writeFile(char* filename, void* buffer) { // TODO: Add length so we don't write too much/too little
     fileEntry_t* file = findFile(filetable);
     if (file == NULL) { // File exists -> override
         // File doesn't exist -> create new file
@@ -74,6 +75,7 @@ void writeFile(char* filename, void* buffer) { // TODO: Add length so we don't w
     }
 
     diskWrite(file->startAddress, file->length, buffer); // Write the file
+    return 0; // Success
 }
 
 void printFiletable(char* ft) {

include/memory/addresses.h

@@ -1,10 +1,18 @@
 #ifndef ADDRESSES_H
 #define ADDRESSES_H
 
-#define MEMMAP_AREA 0x30000
+// Locations
-#define KERNEL_LOC 0x50000
+#define KERNEL_LOC              0x100000
-#define FILETABLE_LOC 0x7000
+#define FILETABLE_LOC           0x7000
-#define SMAP_ENTRY_COUNT 0x8500
+
-#define SMAP_ENTRIES 0x8504
+// Physical memory manager
+#define MEMMAP_AREA             0x30000
+#define SMAP_ENTRY_COUNT        0x8500
+#define SMAP_ENTRIES            0x8504
+#define PHYS_MEM_MAX_BLOCKS     0x1804
+#define PHYS_MEM_USED_BLOCKS    0x1808
+
+// Virtual memory manager
+#define CURRENT_PAGE_DIR_ADDR   0x1800
 
 #endif

src/filetable.asm

@@ -10,13 +10,15 @@
 ;;
 
 filetable:
-    db "boot",0,0,0,0,0,0, "bin",0,0,5
+    db "boot",0,0,0,0,0,0, "bin",0,0,1
-    db "filetable",0,      "tab",0,5,1
+    db "stage2",0,0,0,0,   "bin",0,1,4
-    db "kernel",0,0,0,0,   "bin",0,6,40
+    db "stage3",0,0,0,0,   "bin",0,5,10
-    db "term16n",0,0,0,    "fnt",0,46,4
+    db "filetable",0,      "tab",0,15,1
-    db "testfont",0,0,     "fnt",0,50,4
+    db "kernel",0,0,0,0,   "bin",0,16,40
-    db "test",0,0,0,0,0,0, "txt",0,54,1
+    db "term16n",0,0,0,    "fnt",0,56,4
-    db "calc",0,0,0,0,0,0, "bin",0,55,2
+    db "testfont",0,0,     "fnt",0,60,4
+    db "test",0,0,0,0,0,0, "txt",0,64,1
+    db "calc",0,0,0,0,0,0, "bin",0,65,2
 
 times 512-($-$$) db 0
 

src/kernel.c

@@ -29,7 +29,12 @@ void printPhysicalMemmap();
 
 __attribute__ ((section("entry")))
 void main() {
-    diskRead(5, 1, filetable);
+    // Retrieve global variables
+    currentPd = (pageDirectory_t*)*(uint32_t*)CURRENT_PAGE_DIR_ADDR; // Don't ask
+    memoryMap = (uint32_t*)MEMMAP_AREA;
+    maxBlocks = *(uint32_t*)PHYS_MEM_MAX_BLOCKS;
+    usedBlocks = *(uint32_t*)PHYS_MEM_USED_BLOCKS;
+
     // Interrupt setup
     setupIdt();
     setupExceptions();
@@ -42,40 +47,11 @@ void main() {
     setupTimer();
     setupRtc();
     setupKeyboard();
-
+ 
-    // Physical memory manager setup
-    uint32_t smapEntryCount = *(uint32_t*)SMAP_ENTRY_COUNT;
-    smapEntry_t* smapEntries = (smapEntry_t*)SMAP_ENTRIES; // After a unit32_t
-    uint32_t totalMemory = smapEntries[smapEntryCount - 1].baseAddress + smapEntries[smapEntryCount - 1].length - 1;
-
-    setupPhysicalMemoryManager(MEMMAP_AREA, totalMemory);
-
-    for (uint32_t i = 0; i < smapEntryCount; i++) {
-        if (smapEntries[i].type == 1) {
-            initMemoryRegion(smapEntries[i].baseAddress, smapEntries[i].length);
-        }
-    }
-
-    deinitMemoryRegion(0x1000, 0x9000); // Reserve kernel memory (under 0xa000)
-    deinitMemoryRegion(MEMMAP_AREA, maxBlocks / BLOCKS_PER_BYTE);
-
-    // Virtual memory manager setup
-    setupVirtualMemoryManager(); // TODO: Check if it succeeds
-
-    // Identity map VBE framebuffer
-    uint32_t fbSize = (gfxMode->yRes * gfxMode->linearBytesPerScanline) / PAGE_SIZE;
-    if (fbSize % PAGE_SIZE > 0) { fbSize++; }
-    fbSize *= 2; // Double for hardware
-    for (uint32_t i = 0, fbStart = gfxMode->physicalBasePtr; i < fbSize; i++, fbStart += PAGE_SIZE) {
-        mapPage((void*)fbStart, (void*)fbStart);
-    }
-    deinitMemoryRegion(gfxMode->physicalBasePtr, fbSize * BLOCK_SIZE);
-
     // Screen setup
     readFile("term16n.fnt", font);
     clear();
     print("kern.\n\n");
-
     
     // Run Interactive Shell Program
     // TODO: Make it in another file

src/kernel.ld

@@ -1,5 +1,5 @@
 SECTIONS {
-    .text 0x50000 : {
+    .text 0xC0000000 : {
         *(entry);
         *(.text*);
     }

src/stage1.asm

@@ -3,8 +3,7 @@
 [global start]
 
 %define VIDMEM 0xb800
-%define FILETAB_LOC 0x7000 ; TODO: Read kernel size and location from ft
+%define FILETAB_LOC 0x7000
-%define KERNEL_SIZE 40 ; 20kB
 
 start:
     mov [driveNum], dl   ; Store the drive number
@@ -37,7 +36,7 @@ start:
     mov ah, 2   ; Read from disk
     int 0x13    ; Read interrupt
 
-    jnc loadKernel
+    jnc loadPrekernel
 
     dec byte [counter]
     jnz .read
@@ -58,20 +57,20 @@ diskErr:
     cli
     hlt
 
-loadKernel:
+loadPrekernel:
     mov byte [counter], 3
 
 .read:
     ; Location
-    mov ax, 0x5000 ; Making es 0x5000 will load the kernel at 0x50000
+    mov ax, 0x5000 ; Making es 0x5000 will load the prekernel at 0x50000
     mov es, ax
     xor bx, bx
     
     ; CHS Location
-    mov al, KERNEL_SIZE
+    mov al, 10  ; Prekernel size
     mov ch, 0   ; Cylinder
     mov dh, 0   ; Head
-    mov cl, 7   ; Sector
+    mov cl, 6   ; Sector
     mov dl, [driveNum]
 
     mov ah, 2   ; Read from disk

src/stage2.asm

@@ -1,7 +1,7 @@
 [bits 16]
 [org 0x7e00]
 
-%define KERNEL_LOC 0x50000
+%define STAGE3_LOC 0x50000
 %define VIDMEM 0xb800
 
 start:
@@ -324,7 +324,7 @@ protected_start:
     rep movsd
 
     ; Perform The far jump
-    jmp CODE_SEG:KERNEL_LOC
+    jmp CODE_SEG:STAGE3_LOC
 
 ;; Data
 driveNum: db 0

src/stage3.c

@@ -0,0 +1,62 @@
+#include <memory/physical.h>
+#include <memory/virtual.h>
+#include <memory/addresses.h>
+#include <disk/disk.h>
+#include <disk/filesys.h>
+#include <screen/text.h>
+
+__attribute__ ((section("entry")))
+void main() {
+    diskRead(15, 1, filetable); // Load filetable into memory; TODO: Make a filetableUpdate() function that just keeps the stored and memory verisons in sync
+    
+    // Physical memory manager setup
+    uint32_t smapEntryCount = *(uint32_t*)SMAP_ENTRY_COUNT;
+    smapEntry_t* smapEntries = (smapEntry_t*)SMAP_ENTRIES; // After a unit32_t
+    uint32_t totalMemory = smapEntries[smapEntryCount - 1].baseAddress + smapEntries[smapEntryCount - 1].length - 1;
+
+    setupPhysicalMemoryManager(MEMMAP_AREA, totalMemory);
+
+    for (uint32_t i = 0; i < smapEntryCount; i++) {
+        if (smapEntries[i].type == 1) {
+            initMemoryRegion(smapEntries[i].baseAddress, smapEntries[i].length);
+        }
+    }
+
+    deinitMemoryRegion(0x1000, 0x9000); // Reserve kernel memory (under 0xa000)
+    deinitMemoryRegion(MEMMAP_AREA, maxBlocks / BLOCKS_PER_BYTE);
+
+    // Load kernel into memory
+    if (readFile("kernel.bin", (void*)KERNEL_LOC) != 0) { // Check if kernel.bin was loaded
+        // TODO: Add error messages
+        while (1);
+    }
+
+    // Virtual memory manager setup
+    if (setupVirtualMemoryManager() != 0) {
+        while (1);
+    }
+
+    // Identity map VBE framebuffer
+    uint32_t fbSize = (gfxMode->yRes * gfxMode->linearBytesPerScanline) / PAGE_SIZE;
+    if (fbSize % PAGE_SIZE > 0) { fbSize++; }
+    fbSize *= 2; // Double for hardware
+    for (uint32_t i = 0, fbStart = gfxMode->physicalBasePtr; i < fbSize; i++, fbStart += PAGE_SIZE) {
+        mapPage((void*)fbStart, (void*)fbStart);
+    }
+    deinitMemoryRegion(gfxMode->physicalBasePtr, fbSize * BLOCK_SIZE);
+
+    *(uint32_t*)PHYS_MEM_MAX_BLOCKS = maxBlocks;
+    *(uint32_t*)PHYS_MEM_USED_BLOCKS = usedBlocks;
+
+    for (uint32_t virt = KERNEL_LOC; virt < 0x400000; virt += PAGE_SIZE) {
+        unmapPage((void*)virt);
+    }
+
+    __asm__ volatile ("movl %cr3, %ecx; movl %ecx, %cr3");
+
+    *(uint32_t*)CURRENT_PAGE_DIR_ADDR = (uint32_t)currentPd;
+
+    // Call/jump to kernel
+    ((void(*)(void))0xC0000000)();
+}
+

src/stage3.ld

@@ -0,0 +1,16 @@
+/* Third stage "prekernel" */
+SECTIONS {
+    .text 0x50000 : {
+        *(entry);
+        *(.text*);
+    }
+    .data : {
+        *(.data*);
+    }
+    .rodata : {
+        *(.rodata*);
+    }
+    .bss : {
+        *(.bss*);
+    }
+}