Merge remote-tracking branch 'origin' into higher-halve-kernel-#25

Makefile

@@ -5,7 +5,7 @@ all:
 	mv kernel bootdir/boot/kernel.elf
 	cp grub.cfg bootdir/boot/grub
 	grub-mkrescue -o kernel.iso bootdir --compress=xz
-	qemu-system-i386 -cdrom kernel.iso -d int,cpu_reset -no-reboot
+	qemu-system-i386 -cdrom kernel.iso -m 1024M
 
 debug:
 	rm -rf kernel.iso
@@ -14,4 +14,4 @@ debug:
 	mv kernel bootdir/boot/kernel.elf
 	cp grub.cfg bootdir/boot/grub
 	grub-mkrescue -o kernel.iso bootdir --compress=xz
-	qemu-system-i386 -cdrom kernel.iso -gdb tcp::1234 -S #-d int,cpu_reset -no-reboot
+	qemu-system-i386 -cdrom kernel.iso -m 1024M -gdb tcp::1234 -S

src/PMM.zig

@@ -0,0 +1,101 @@
+const multiboot = @import("multibootheader.zig");
+const print = @import("print.zig").print;
+const panic = @import("print.zig").panic;
+const panicLevels = @import("print.zig").panicLevel;
+
+// 
+// PMM = Physical Memory Manager
+// 
+const PAGE_SIZE = 4096;
+const FREE = 0;
+const USED = 1;
+
+pub var totalMemory: u32 = 0; // in KiB
+pub var usedBlocks: u32 = 0;
+pub var maxBlocks: u32 = 0;
+var MMAP: [*]u1 = undefined;
+
+pub fn init(mbd: *multiboot.multiboot_info, magic: u32) void {
+    if (mbd.flags & 0x1 == 0)
+        panic("Invalide memory size", panicLevels.HIGH);
+    if (magic != multiboot.MULTIBOOT_BOOTLOADER_MAGIC) 
+        panic("Invalide magic number", panicLevels.HIGH);
+    if (mbd.flags >> 6 & 0x1 == 0) 
+        panic("Invalide memory map", panicLevels.HIGH);
+
+    totalMemory = mbd.mem_lower + mbd.mem_upper;
+    maxBlocks = (totalMemory * 1024) / PAGE_SIZE;
+
+    MMAP = @ptrFromInt(0x200000);
+
+    // set all memory used
+    for (0..maxBlocks) |i| {
+        MMAP[i] = USED;
+    }
+
+    // set all memory that is free to free
+    print("\n", .{});
+    var entry: u32 = mbd.mmap_addr;
+    while (entry < mbd.mmap_addr + mbd.mmap_length) {
+        const entryStruct: *align(8) multiboot.multiboot_mmap_entry = @ptrFromInt(entry);
+        const addr: u32 = @truncate(entryStruct.addr);
+        const len: u32 = @truncate(entryStruct.len);
+        const etype: u32 = entryStruct.type;
+        print("Start Addr: {x} | Length: {x} | Size: {x} | Type: {}\n", .{addr, len, entryStruct.size, etype});
+
+        if (etype == multiboot.MULTIBOOT_MEMORY_AVAILABLE) {
+            const start = addr / PAGE_SIZE;
+            const range = len / PAGE_SIZE;
+
+            for (start..start + range) |i| {
+                MMAP[i] = FREE;
+            }
+        }
+
+        entry = entry + entryStruct.size + @sizeOf(@TypeOf(entryStruct.size));
+    }
+
+    // set the first page as used so address 0 is allways in use
+    MMAP[0] = USED;
+
+    reallocMMAP() catch panic("OUT_OF_MEMORY", panicLevels.HIGH);
+}
+
+fn reallocMMAP() !void {
+    const oldMMAP = MMAP;
+
+    const new = maxBlocks / 8 / PAGE_SIZE + 1;
+    MMAP = @ptrFromInt(try getPages(new));
+
+    for (0..maxBlocks) |i| {
+        MMAP[i] = oldMMAP[i];
+    }
+}
+
+pub fn getPages(amount: usize) !usize {
+    for (0..maxBlocks - amount) |i| {
+        if (MMAP[i] == FREE) { // look for free memory
+            for (0..amount) |j| {
+                if (MMAP[i + j] == USED) { // see if every memory for the amount is free
+                    break;
+                }
+                if (j == amount - 1) {
+                    for (0..amount) |k| {
+                        MMAP[i + k] = USED; // set memory used
+                    }
+                    return i * PAGE_SIZE;
+                }
+            }
+        }
+    }
+    return error.OUT_OF_MEMORY;
+}
+
+pub fn freePages(addr: usize, amount: usize) void {
+    const pos = addr / PAGE_SIZE;
+
+    for (pos..amount) |i| {
+        if (pos + i < maxBlocks)
+            MMAP[pos + i] = FREE;
+    }
+}

src/boot.s

@@ -30,12 +30,14 @@
 	stack_bottom:
 		.skip 4096
 	stack_top:
+
 
 .section .text
 	_start:
-
 		mov $stack_top, %esp
 
+        push %eax
+        push %ebx
 		call kernel_main
 
 		hang:

src/main.zig

@@ -1,3 +1,4 @@
+const multiboot = @import("multibootheader.zig");
 const console = @import("console.zig").Console;
 const port = @import("ports.zig");
 const keyboard = @import("keyboard.zig").Keyboard;
@@ -8,12 +9,14 @@ const print = @import("print.zig").print;
 const printStack = @import("print.zig").printStack;
 const IDT = @import("idt.zig");
 const PIC = @import("pic.zig");
-const MEMORY = @import("memory.zig");
+const mem = @import("PMM.zig");
 
-export fn kernel_main() void {
+export fn kernel_main(mbd: *multiboot.multiboot_info, magic: u32) void {
     GDT.gdt.init();
     PIC.remapPic();
     IDT.idt.init();
+    mem.init(mbd, magic);
+
     console.clear();
     console.setActiveBuffer(0) catch unreachable;
     console.setColor(VGA.DarkGray, VGA.Black);